U.S. SILICA HOLDINGS, INC. - Annual Report: 2013 (Form 10-K)

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

For the Fiscal Year Ended December 31, 2013

OR

Commission file number 1-35416

U.S. Silica Holdings, Inc.

(Exact name of registrant as specified in its charter)

8490 Progress Drive, Suite 300

Frederick, Maryland 21701

(Address of Principal Executive Offices) (Zip Code)

(301) 682-0600

(Registrant’s telephone number, including area code)

Securities registered pursuant to Section 12(b) of the Securities Act:

Securities registered pursuant to Section 12(g) of the Securities Act:

None

Indicate by a check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.    Yes  þ    No  ¨

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15 (d) of the Act.    Yes  ¨    No  þ

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  þ    No  ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its website, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    Yes  ¨    No  þ

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§229.405 of this chapter) is not contained herein, and will not be contained, to the best of the registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form    10-K.  ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act.

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act).    Yes  ¨    No  þ

The aggregate market value of the outstanding common stock held by non-affiliates of the registrant as of June 28, 2013, the last business day of the registrant’s most recently completed second fiscal quarter, was $735,673,841, based on the closing price of $20.78 per share, as reported on the New York Stock Exchange.

As of February 21, 2014, 53,551,879 shares of the common stock of the registrant were issued and outstanding.

DOCUMENTS INCORPORATED BY REFERENCE

Part III of Form 10-K             Certain sections of the Proxy Statement for the 2014 Annual Meeting of Shareholders for U.S. Silica Holdings, Inc.

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U.S. Silica Holdings, Inc.

FORM 10-K

For the Fiscal Year Ended December 31, 2013

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Forward-Looking Statements

This Annual Report on Form 10-K contains forward-looking statements that are subject to risks and uncertainties. All statements other than statements of historical fact included in this Annual Report on Form 10-K are forward-looking statements. Forward-looking statements give our current expectations and projections relating to our financial condition, results of operations, plans, objectives, future performance and business. You can identify forward-looking statements by the fact that they do not relate strictly to historical or current facts. These statements may include words such as “anticipate,” “estimate,” “expect,” “project,” “plan,” “intend,” “believe,” “may,” “will,” “should,” “can have,” “likely” and other words and terms of similar meaning in connection with any discussion of the timing or nature of future operating or financial performance or other events. For example, all statements we make relating to our estimated and projected costs, expenditures, cash flows, growth rates and financial results, our plans and objectives for future operations, growth or initiatives, strategies or the expected outcome or impact of pending or threatened litigation are forward-looking statements. All forward-looking statements are subject to risks and uncertainties that may cause actual results to differ materially from those that we expected, including:

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We derive many of our forward-looking statements from our operating budgets and forecasts, which are based on many detailed assumptions. While we believe that our assumptions are reasonable, we caution that it is very difficult to predict the impact of known factors, and it is impossible for us to anticipate all factors that could affect our actual results. Important factors that could cause actual results to differ materially from our expectations, or cautionary statements, are disclosed under Item 1A, “Risk Factors” and Item 7, “Management’s Discussion and Analysis of Financial Condition and Results of Operations” in this Annual Report on Form 10-K. All written and oral forward-looking statements attributable to us, or persons acting on our behalf, are expressly qualified in their entirety by these cautionary statements as well as other cautionary statements that are made from time to time in our other filings with the Securities and Exchange Commission (the “SEC”) and public communications. You should evaluate all forward-looking statements made in this Annual Report on Form 10-K in the context of these risks and uncertainties.

We caution you that the important factors referenced above may not contain all of the factors that are important to you. In addition, we cannot assure you that we will realize the results or developments we expect or anticipate or, even if substantially realized, that they will result in the consequences or affect us or our operations in the way we expect. The forward-looking statements included in this Annual Report on Form 10-K are made only as of the date hereof. We undertake no obligation to update or revise any forward-looking statement as a result of new information, future events or otherwise, except as otherwise required by law.

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PART I.

Unless we state otherwise or the context otherwise requires, the terms “we,” “us,” “our,” “U.S. Silica,” “the Company,” “our business,” “our company” refer to U.S. Silica Holdings, Inc. and its consolidated subsidiaries as a combined entity. Adjusted EBITDA as used herein is a non-GAAP measure. For a detailed description of Adjusted EBITDA, please see the discussion under “Management’s Discussion and Analysis of Financial Condition and Results of Operations – How We Evaluate Our Business – Adjusted EBITDA.”

Our Company

Business Overview

We are one of the largest domestic producers of commercial silica, a specialized mineral that is a critical input into a variety of attractive end markets. During our 113-year history, we have developed core competencies in mining, processing, logistics and materials science that enable us to produce and cost-effectively deliver over 250 products to customers across these markets. In our largest end market, oil and gas proppants, our frac sand is used to stimulate and maintain the flow of hydrocarbons in oil and natural gas wells. This segment of our business is experiencing rapid growth due to recent technological advances in the hydraulic fracturing process, which have made the extraction of large volumes of oil and natural gas from U.S. shale formations economically feasible. Our silica is also used as an economically irreplaceable raw material in a wide range of industrial applications, including glassmaking and chemical manufacturing. Additionally, in recent years a number of attractive new end markets have developed for our high-margin, performance silica products, including high-performance glass, specialty coatings, polymer additives and geothermal energy systems.

As of February 26, 2014, we operate 15 production facilities across the United States and control 297 million tons of reserves, including approximately 138 million tons of reserves that can be processed to meet the American Petroleum Institute (“API”) frac sand size specifications. We produce a wide range of frac sand sizes and are one of the few commercial silica producers capable of rail delivery of large quantities of API grade frac sand to most of the major U.S. shale basins. We believe that, due to a combination of these favorable attributes and robust drilling activity in the oil and natural gas industry, we have become a preferred commercial silica supplier to our customers in the oil and gas proppants end market and, consequently, have experienced high demand for our frac sand. To meet this demand, we continue to invest significant resources to increase our proppant production.

Our operations are organized into two segments based on end markets served: (1) Oil & Gas Proppants and (2) Industrial & Specialty Products. Our segments are complementary because our ability to sell to a wide range of customers across end markets allows us to maximize recovery rates in our mining operations, optimize our asset utilization and reduce the cyclicality of our earnings. In 2013, we generated approximately $546.0 million of sales, $160.7 million of Adjusted EBITDA and $75.3 million of net income. These figures represent increases of 24% and 7% and a decrease of 5%, respectively, compared to 2012.

Corporate History

In August 2007, we were acquired by an affiliate of Harvest Partners, LLC. Soon thereafter, in October 2007, we were acquired by Hourglass Acquisition I, LLC, a direct, wholly owned subsidiary of Harbinger Capital Partners. In November 2008, Hourglass Acquisition I, LLC was acquired by U.S. Silica Holdings, Inc., formerly GGC USS Holdings, Inc., a wholly-owned subsidiary of GGC USS Holdings, LLC (“GGC Holdings”), an affiliate of Golden Gate Capital (“Golden Gate Capital”). The Company was formed by Golden Gate Capital as a Delaware corporation to effect the acquisition of Hourglass Acquisition I, LLC, and through that acquisition U.S. Silica Company, our principal operating subsidiary, became an indirect, wholly owned subsidiary of the Company.

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On January 31, 2012, simultaneously with the initial public offering of our common stock, GGC Holdings, our sole stockholder prior to the IPO, contributed to us all of the stock of its wholly-owned subsidiary, GGC RCS Holdings, Inc., and its operating subsidiary, Coated Sand Solutions, LLC. Prior to this transaction, GGC RCS Holdings, Inc. had a $15.0 million note payable to GGC Holdings which, together with accrued interest of $1.7 million, was converted to an equity contribution by GGC Holdings, simultaneously with the IPO. Coated Sand Solutions develops resin-coated sand proppants for sale into the oil and gas proppants market for use in the hydraulic fracturing process and into the foundry market.

As of December, 31, 2013, GGC USS Holdings, LLC held no interest in U.S. Silica after divesting its ownership interest in U.S. Silica during 2013.

Our Strengths

We attribute our success to the following strengths:

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Our Strategy

The key drivers of our growth strategy include:

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Our Industry

The commercial silica industry consists of businesses that are involved in the mining, processing and sale of commercial silica. Commercial silica, also referred to as “silica,” “industrial sand and gravel,” “silica sand” and “quartz sand,” is a term applied to sands and gravels containing a high percentage of silica (silicon dioxide, SiO2) in the form of quartz. Commercial silica deposits occur throughout the United States, but mines and processing facilities are typically located near end markets and in areas with access to transportation infrastructure. Other factors affecting the feasibility of commercial silica production include deposit composition, product quality specifications, land-use and environmental regulation, including permitting requirements, access to electricity, natural gas and water and a producer’s expertise and know-how.

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Market and Industry Data

We obtained the industry, market and competitive position data used in this Annual Report on Form 10-K from our own internal estimates and research as well as from industry and general publications and research, surveys and studies conducted by third parties. We have relied upon publications of The Freedonia Group, Inc. (“Freedonia”) as our primary sources for third-party market and industry data. Industry publications, surveys and studies generally state that the information contained therein has been obtained from sources believed to be reliable, although they do not guarantee the accuracy or completeness of such information. While we believe that each of these publications, surveys and studies is reliable, we have not independently verified market and industry data from third-party sources. While we believe our internal company research is reliable and the definitions of our market and industry are appropriate, neither such research nor these definitions have been verified by any independent source.

Extraction and Production Processes

Commercial silica deposits are formed from a variety of sedimentary processes and have distinct characteristics that range from hard sandstone rock to loose, unconsolidated dune sands. While the specific extraction method utilized depends primarily on the deposit composition, most silica is mined using conventional open-pit bench extraction methods and begins after clearing the deposit of any overlaying soil and organic matter. The silica deposit composition and chemical purity also dictate the processing methods and equipment utilized. For example, broken rock from a sandstone deposit may require one, two or three stages of crushing to liberate the silica grains required for most markets. Unconsolidated deposits may require little or no crushing, as silica grains are not tightly cemented together.

After extracting the ore, the silica is washed with water to remove fine impurities such as clay and organic particles. In some deposits, these fine contaminants or impurities are tightly bonded to the surface of the silica grain and require attrition scrubbing to be removed. Other deposits require the use of flotation to collect and separate contaminants from the silica. When these contaminants are weakly magnetic, special high intensity magnets may be utilized in the process to improve the purity of the final commercial silica product. After the silica has been washed, most output is dried prior to sale.

The final step in the production process involves the classification of commercial silica products according to their chemical purity, particle shape and particle size distribution. Generally, commercial silica is produced and sold in either whole grain (unground) form or ground form. Whole grain silica generally ranges from 12 to 140 mesh. Mesh refers to the number of openings per linear inch on a sizing screen. Whole grain silica products are sold in a range of shapes, sizes and purity levels to be used in a variety of industrial applications, such as glass, foundry, building products, oil and natural gas recovery, filtration and recreation. Some whole grain silica is further processed to ground silica of much smaller particle sizes, ranging from 5 to 250 microns. A micron is one-millionth of a meter.

Product Distribution

Most commercial silica is shipped in bulk to customers by truck or rail. There has been a shift away from truck to rail, as more volumes have been directed to the oil and gas proppants end market, which typically utilizes rail transportation.

For bulk commercial silica, transportation cost represents a significant portion of the overall product cost. Consequently, the majority of production transported by truck is sold within approximately 200 miles of the producing facility. This limitation emphasizes the importance of rail or barge access for low cost delivery outside of the 200-mile truck radius. As a result, facility location is one of the most important considerations for producers and customers. These factors dictate the all-in delivered cost of silica production. Exceptions to this include frac sands used in oil and natural gas recovery and finer grade commercial silica, where transporting the materials long distances is economically feasible due to the relatively high unit values.

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In addition to bulk shipments, commercial silica products can be packaged and shipped in 50 to 100 pound bags or bulk super sacks. Bag shipments are usually made to smaller customers with batch operations, warehouse distributor locations or for ocean container shipments made overseas. The products that are shipped in bags are often higher value products, such as ground and fine ground industrial silica.

Primary End Markets

The special properties of commercial silica—chemistry, purity, grain size, color, inertness, hardness and resistance to high temperatures—make it critical to a variety of industries. Commercial silica is a key input in the well completion process, specifically, in the hydraulic fracturing techniques used in unconventional oil and natural gas wells. In the industrial and specialty products end markets, stringent quality requirements must be met when commercial silica is used as an ingredient to produce thousands of everyday products, including glass, building and foundry products and metal castings, as well as certain specialty applications such high-performance glass, specialty coatings, polymer additives and geothermal energy systems. Due to the unique properties of commercial silica, it is an economically irreplaceable raw material in a wide range of industrial applications. Our major end markets include:

Oil and Gas Proppants

Commercial silica is used as a proppant by companies involved in oil and natural gas recovery in conventional and unconventional resource plays. Unconventional oil and natural gas production requires hydraulic fracturing and other well stimulation techniques to recover oil or natural gas that is trapped in the source rock and typically involves horizontal drilling. Frac sand is pumped down oil and natural gas wells at high pressures to prop open rock fissures in order to increase the flow rate of hydrocarbons from the wells. Additionally, every 4 to 5 years proppants may be used to “re-fracture” the reservoir and keep the fractures open. According to the most recent related Freedonia report dated August 2013, domestic proppant producers are expected to experience annual increases in demand of 11% through 2017. Based on our own internal and other third-party estimates, we believe commercial silica used by the oil and gas proppants end market increased significantly in 2011 and likely accounted for approximately 44% of total commercial silica volumes in the U.S.

Glass

Commercial silica is a critical input into and accounts for 60% to 70% of the raw materials in glass production. The glassmaking markets served by commercial silica producers include containers, flat glass, specialty glass and fiberglass. Demand typically varies within each of these end markets. See “Risk Factors—Risks Related to Our Business—Our operations are subject to the cyclical nature of our customers’ businesses, and we may not be able to mitigate that risk.”

The container glass, flat glass and fiberglass end markets are generally mature end markets. Demand for container glass has historically grown in line with population growth, and we expect similar growth in the future. Flat glass and fiberglass tend to be correlated with construction and automotive production activity, both of which have been improving during the past couple of years. To the extent construction and domestic automotive production activity continues its recovery in the coming years, which is difficult to predict given current economic uncertainty, we expect that demand in these end markets will continue to increase. Specific markets such as those for solar glass have been negatively impacted by generally weak demand. Some of the anticipated growth in the glass markets may be offset through the use of recycled glass. See “Risk Factors—Risks Related to Our Business—Our operations are subject to the cyclical nature of our customers’ businesses, and we may not be able to mitigate that risk.”

Building Products

Commercial silica is used in the manufacturing of building products for commercial and residential construction. Whole grain commercial silica products are used in flooring compounds, mortars and grouts,

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specialty cements, stucco and roofing shingles. Ground commercial silica products are used by building products manufacturers as functional extenders and to add durability and weathering properties to cementious compounds. In addition, geothermal wells are an alternative energy source that requires specialized ground silica products in their well casings for effectiveness. The market for commercial silica used to manufacture building products is driven primarily by the demand in the construction markets. The historical trend for this market has been one of growth, especially in demand for cementious compounds for new construction, renovation and repair. Although the housing construction market experienced a significant decline beginning in 2006 and continuing through 2011, we began to see an increase in permits and housing starts in 2012, gains that have continued during 2013. To the extent the housing market recovery continues in the coming years, which is difficult to predict given current economic uncertainty, we expect that demand in this end market will increase. See “Risk Factors—Risks Related to Our Business—Our operations are subject to the cyclical nature of our customers’ businesses, and we may not be able to mitigate that risk.”

Foundry

Commercial silica products are used in the production of molds for metal castings and in metal casting products. In addition, commercial whole grain silica is sold to coaters of foundry silica who then sell their product to foundries for cores and shell casting processes. The demand for foundry silica primarily depends on the rate of automobile and light truck production, construction and production of heavy equipment like rail cars. Over the past decade, there has been some movement of foundry supply chains to Mexico and other offshore production areas. In 2010, foundry demand decreased significantly as a result of the decrease in automotive and heavy equipment production. However, we began seeing increases in foundry demand in 2011 and throughout 2012. In 2013, the foundry market growth appears to have leveled off, with growth more in line with the general economy. To the extent production levels continue to strengthen in the coming years, which is difficult to predict given current economic uncertainty, we expect foundry demand to continue to increase. See “Risk Factors—Risks Related to Our Business—Our operations are subject to the cyclical nature of our customers’ businesses, and we may not be able to mitigate that risk.”

Chemicals

Both whole grain and ground silica products are used in the manufacturing of silicon-based chemicals, such as sodium silicate, that are used in a variety of applications, including food processing, detergent products, paper textile, specialty foundry applications and as inputs for some precipitated silicas. This end market is driven by the development of new products by the chemicals manufacturers, including specialty coatings and polymer additives as well as the growth of “green” tires. We expect this end market to grow as these manufacturers continue their product and applications development. See “Risk Factors—Risks Related to Our Business—Our operations are subject to the cyclical nature of our customers’ businesses, and we may not be able to mitigate that risk.”

Fillers and Extenders

Commercial silica and kaolin clay products are sold to producers of paints and coating products for use as fillers and extenders in architectural, industrial and traffic paints and are sold to producers of rubber and plastic for use in the production of epoxy molding compounds and silicone rubber. The commercial silica products used in this end market are most often ground silica, including finer ground classifications. The market for fillers and extenders is driven by demand in the construction and automotive production industries as well as by demand for materials in the housing remodeling industry. Although construction, domestic automotive production and housing remodeling demand decreased in 2009, we have continued to see strengthening in these sectors throughout 2013. To the extent these industries continue to recover in the coming years, which is difficult to predict given current economic uncertainty, we expect demand to improve. See “Risk Factors—Risks Related to Our Business—Our operations are subject to the cyclical nature of our customers’ businesses, and we may not be able to mitigate that risk.”

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Demand Trends

U. S. demand for industrial silica has been growing steadily. According to “Freedonia”, demand for industrial silica sand grew at a 4% compound annual growth rate (“CAGR”) from 2001 to 2011. This increase in demand was driven primarily by hydraulic fracturing, which grew at a 27% CAGR from 2001 to 2011, according to the most recent related Freedonia report dated October 2012. More recently, the recovery of the U.S. housing and automotive markets has also positively affected silica demand related to those markets such as glass, building materials, foundry and fillers and extenders. Trends driving the acceleration in demand include:

Supply

During 2013, the market increased supply to meet recent shortages and appears to be balanced, though shortages persist among certain coarse grades and certain surpluses have emerged in other grades. The year was also marked by the entry of multiple new players in the silica mining business, concentrated in Wisconsin and Minnesota. New entrants faced serious hurdles to establish their operations, including:

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Many projects were abandoned, postponed or delayed due to these difficulties. The new entrants who were able to establish themselves often had high cost structures which resulted from these factors. See “Risk Factors—Risks Related to Our Business—Our operations are subject to the cyclical nature of our customers’ businesses, and we may not be able to mitigate that risk.”

Pricing

Historically, commercial silica has been characterized by regional markets created by the high weight-to-value ratio of silica. From 2000 to 2012, the increased demand for commercial silica from our customers in both the oil and gas proppants end market and industrial and specialty products end markets and limited supply increases resulted in favorable pricing trends in both of our operating segments. From 2001 to 2011, North America commercial silica prices increased at an average annual rate of 5.9%, according to the most recent related Freedonia report dated October 2012. In December 2012, the U.S. Bureau of Labor Statistics released a Frac Sand Producer Price Index, starting at 100, which measures the average change over time in the selling prices received by domestic producers of hydraulic fracturing sand. For December 2013, the preliminary Frac Sand Producer Price Index was 90.3, a decline of 9.7 points; however, the preliminary index for January 2014 was 92.3, an increase of 2.0 points from the prior month.

See “Risk Factors—Risks Related to Our Business—Our operations are subject to the cyclical nature of our customers’ businesses, and we may not be able to mitigate that risk.”

Our Products

In order to serve a broad range of end markets, we produce and sell a variety of commercial silica products, including whole grain and ground products, as well as other industrial mineral products that we believe complement our commercial silica products.

Whole Grain Silica Products—We sell whole grain commercial silica products in a range of shapes, sizes and purity levels. We sell whole grain silica that has a round shape and high crush strength to be used as frac sand in connection with oil and natural gas recovery, and we have constructed a production facility for resin-coated sand that became fully operational in 2013. We also sell whole grain silica products in a range of size distributions, grain shapes and chemical purity levels to our customers involved in the manufacturing of glass products, including a low-iron whole grain product sold to manufacturers of architectural and solar glass applications. In addition, we sell several grades of whole grain round silica to the foundry industry and provide whole grain commercial silica to the building products industry. Sales of whole grain commercial silica products accounted for approximately 85%, 82% and 78% of our total sales revenue for 2013, 2012 and 2011, respectively.

Ground Silica Products—Our ground commercial silica products are inherently inert, white and bright, with high purity. We market our ground silica in sizes ranging from 40 to 250 microns for use in plastics, rubber, polishes, cleansers, paints, glazes, textile fiberglass and precision castings. We also produce and market fine ground silica in sizes ranging from 5 to 40 microns for use in premium paints, specialty coatings, sealants, silicone rubber and epoxies. We believe we are currently the only commercial silica producer in the United States that manufactures a 5-micron product. Sales of ground silica products accounted for approximately 12%, 14% and 16% of our total sales revenue for 2013, 2012 and 2011, respectively.

Other Industrial Mineral Products—We also produce and sell certain other industrial mineral products, such as aplite, calcined kaolin clay and magnesium silicate. Aplite is a mineral used to produce container glass and insulation fiberglass and is a source of alumina that has a low melting point and a low tendency to form defects in glass. Calcined kaolin clay is a mineral primarily used as a functional extender. Calcined kaolin clay is chemically inert, has a high covering power, gives desirable flow properties and reduces the amount of expensive pigments required. These characteristics make calcined kaolin clay an ideal functional extender in paints, plastics, specialty coatings and rubber. We also produce and sell a highly selective adsorbent made from a

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mixture of silica and magnesium, used extensively in preparative and analytical chromatography. Sales of our other industrial mineral products accounted for approximately 3%, 4% and 6% of our total sales revenue for 2013, 2012 and 2011, respectively.

Our Primary End Markets and Customers

We sell our products to a variety of end markets. At the end of 2008, we began investing heavily in our capacity to supply frac sand to customers in the oil and gas proppants end market. Our high-quality reserves of frac sand have enabled us to quickly build a presence in this market, and we have invested in the production of resin-coated sand for the same purpose. Our customers in the oil and gas proppants end market include, among others, Schlumberger Ltd., Nabors Industries Ltd., Texas Specialty Sands, Calfrac, C&J Energy Services, Inc and Pioneer. Sales to the oil and gas proppants end market comprised approximately 64%, 55% and 36% of our total sales revenue in 2013, 2012 and 2011, respectively.

Our primary markets have historically been core industrial end markets with customers engaged in the production of glass, building products, foundry products, chemicals and fillers and extenders. Our diverse customer base drives high recovery rates across our production. We also benefit from strong and long-standing relationships with our customers in each of the industrial and specialty products end markets we serve. In our industrial and specialty products end markets, our customers include such industry leaders as Owens-Illinois, Inc., Owens Corning, Saint-Gobain Glass, The Sherwin-Williams Company and PPG Industries. Sales to our industrial and specialty products end markets comprised approximately 36%, 45% and 64% of our total sales revenue in 2013, 2012 and 2011, respectively.

We primarily sell our products under short term price agreements or at prevailing market rates. For a limited number of our customers, particularly in the oil and gas proppants end market, we sell under long-term, competitively-bid contracts. Sales under these long-term contracts collectively accounted for 40%, 31% and 17% of total company sales revenue in 2013, 2012 and 2011, respectively. Although these long-term contracts would provide us with some downside protection if there were to be a significant reduction in demand for frac sand, we believe that there is, and that there will continue to be, sufficient demand for frac sand such that we would not experience an adverse effect if these long-term contracts are not renewed or are canceled. Historically we have not entered into long-term contracts with our customers in the industrial and specialty products end markets because of the high cost to our customers of switching providers. We typically renegotiate our price agreements with these customers annually.

The following table provides more detail regarding the end markets that we serve and our significant customer relationships in those markets:

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Production

Our 15 production facilities are located primarily in the eastern half of the United States, with operations in Alabama, Illinois, Louisiana, Michigan, Missouri, New Jersey, Oklahoma, Pennsylvania, South Carolina, Tennessee, Texas, Virginia, West Virginia and Wisconsin.

We conduct only surface mining operations and do not operate any underground mines. Mining methods at our facilities include conventional hard rock mining, hydraulic mining, surface or open-pit mining of loosely consolidated silica deposits and dredge mining. Hard rock mining involves drilling and blasting in order to break up sandstone into sizes suitable for transport to the processing facility by truck, slurry or conveyer. Hydraulic mining involves spraying high-pressure water to break up loosely consolidated sandstone at the mine face. Surface or open-pit mining involves using earthmoving equipment, such as bucket loaders, to gather silica deposits for processing. Lastly, dredging involves gathering silica deposits from mining ponds and transporting them by slurry pipelines for processing. We may also use slurry pipelines in our hydraulic and open-pit mining efforts to expedite processing. Silica mining and processing typically has less of an environmental impact than the mining and processing of other minerals, in part because it uses fewer chemicals.

Our processing plants are equipped to receive the mined sand, wash away impurities, eliminate oversized or undersized particles and remove moisture through a multi-stage drying process. Each of our facilities operates year-round, typically in shift schedules designed to optimize facility utilization in accordance with market demand. Our facilities receive regular preventative maintenance, and we make additional capital investments in our facilities as required to support customer volumes and internal performance goals. For more information related to our production facilities, see Item 2, “Properties”.

In connection with expanding our presence in the oil and gas proppants end market, we finalized construction of a facility to produce resin-coated sand for use in the hydraulic fracturing process, which became fully operational in the first quarter of 2013. In addition, we are constructing a mine and production facility in Utica, Illinois to produce raw sand for use in the hydraulic fracturing process, which we expect to be fully operational by the end of the second quarter of 2014.

Quality Control

We maintain a standard of excellence through our ISO 9001-registered quality systems at our mining and processing facilities. We use automated process control systems that efficiently manage the majority of the mining and processing functions, and we monitor the quality and consistency of our products by conducting hourly tests throughout the production process to detect variances. We generally test each customer load prior to shipment, and all of our major facilities operate a testing laboratory to evaluate and ensure the quality of our products and services. We also provide customers with documentation verifying that all products shipped meet customer specifications. These quality assurance functions ensure that we deliver quality products to our customers and maintain customer trust and loyalty.

In addition, we have certain company-wide quality control mechanisms. We maintain a company-wide quality assurance database that facilitates easy access and analysis of product and process data from all plants. We also have fully staffed and equipped corporate laboratories that provide critical technical expertise, analytical testing resources and application development to promote product value and cost savings. The labs consist of different departments: a foundry lab, a paint and coatings lab, an analytical lab, a minerals-processing lab and an oil and gas lab. The foundry lab is fully equipped for analyzing foundry silica based on grain size distribution, acidity, acid demand value and turbidity, which is a measure of silica cleanliness. The paint and coatings lab provides formulation, application, and testing of paints, coatings and grouts for end use in fillers and extenders as well as building products. The analytical lab performs various analyses on products for quality control assessment. The minerals processing lab models plant production processes to test variations in deposits and improve our ability to meet customer requirements. The oil and gas lab performs testing and provides in-depth analysis of all types of hydraulic fracturing proppants, including frac sand, resin-coated and ceramic

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fracturing proppants, to verify that they meet API size and crush specifications. Additionally, this lab is responsible for the development of new resin-coated products and the technical oversight of our Rochelle, Illinois facility.

Distribution

We ship our commercial silica products direct to our customers by truck, rail or barge. Generally, we utilize trucks for shipments of 200 miles or less from our plant sites and to distribute our bagged products. Given the weight-to-value ratio of most of our products, the majority of our shipments outside this 200-mile radius are by rail. We frequently utilize rail-truck transfer stations to deliver our products to the oil and natural gas industry when this method of transportation provides us with lower delivery costs to specific customers or regions.

Our plant sites are strategically located to provide access to all Class I railroads which enables us to cost effectively send product to each of the strategic shale basins in North America. We can ship product by truck, barge and rail with an ability to connect to short-line railroads as necessary to meet our customers’ evolving in-basin product needs.

We are continuously looking to increase the number of available transload points to which we have access. This approach allows us to provide strong customer service and puts us in a position to take advantage of opportunistic spot market sales. Through our storage facility in San Antonio, Texas, as well as our partnership with Wildcat, we now have storage capacity near all of the major shale basins in the United States. Additionally, we have entered into an agreement with Union Pacific Railroad to build a second storage facility in Odessa, Texas, which is expected to be fully operational by the end of 2014.

All three methods of shipping are typically performed with equipment owned by third parties. Both we and our customers lease a significant number of railcars for shipping purposes, as well as to facilitate the short-term storage of our products, particularly our frac sand products. The railcar leasing market is increasingly tight due to rising demand, and we expect to require additional rail cars as we continue to expand our commercial silica production. As of December 31, 2013, we had a leased fleet of 3,639 rail cars and are currently negotiating additional leases. We believe that we will have access to a sufficient supply of railcars to meet our needs.

For some of our high margin, finer ground commercial silica and other specialty products such as calcined kaolin clay, we can effectively distribute our products nationally and, in some cases, internationally. These sales are typically made through distributors and are shipped by rail to North American locations and by ocean-going barge to international locations.

Our Reserves

We believe we have a broad and high quality mineral reserves base due to our strategically located mines and facilities. At December 31, 2013, we estimate that we had approximately 297 million tons of proven and probable recoverable mineral reserves. The quantity and nature of the mineral reserves at each of our properties are estimated by our internal geologists and mining engineers. Our internal geologists and engineers update our reserve estimates annually, making necessary adjustments for operations at each location during the year and additions or reductions due to property acquisitions and dispositions, quality adjustments and mine plan updates. Before acquiring new reserves, we perform surveying, drill core analysis and other tests to confirm the quantity and quality of the acquired reserves. In some instances, we acquire the mineral rights to reserves without actually taking ownership of the properties. For more information related to our production facilities, deposits and reserves, see Item 2, “Properties”.

Commercial Team

Our commercial team consists of more than 60 individuals responsible for all aspects of our sales process, including pricing, marketing, transportation and logistics, product development and general customer service.

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This necessitates a highly organized staff and extensive coordination between departments. For example, product development requires the collaboration of our sales team, our production facilities and our corporate laboratory. Our sales team interacts directly with our customers in determining their needs, our production facilities fulfill the orders and our corporate laboratory is responsible for ensuring that our products meet those needs.

Our commercial team can be divided into four units:

Many other product analyses are performed locally at our 15 production facilities to support new product development, plant operations and customer quality requirements.

We also have a variety of other technical competencies including process engineering, equipment design, facility construction, maintenance excellence, environmental engineering, geology and mine planning and development. Effective integration of these capabilities has been a critical component of our business success and has allowed us to establish and maintain an extensive, high-quality silica sand reserve base, maximize the value of our reserves by producing and selling a wide range of high-quality products, optimize processing costs to provide strong value to customers and prioritize operating in a safe and environmentally sustainable manner.

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Competition

Both of our reporting segments operate in highly competitive markets that are characterized by a small number of large, national producers and a larger number of small, regional or local producers. According to a January 2013 publication by the United States Geological Survey (“USGS”), in 2012, there were 87 producers of commercial silica with a combined 159 active operations in 33 states within the United States. Competition in the industry across both of our reporting segments is based on price, consistency and quality of product, site location, distribution capability, customer service, reliability of supply, breadth of product offering and technical support. As transportation costs are a significant portion of the total cost to customers of commercial silica—in many instances transportation costs can represent more than 50% of delivered cost—the commercial silica market is typically local, and competition from beyond the local area is limited. Notable exceptions to this are the frac sand and fillers and extenders markets, where certain product characteristics are not available in all deposits and not all plants have the requisite processing capabilities, necessitating that some products be shipped for extended distances.

Because the markets for our products are typically local, we also compete with smaller, regional or local producers. For instance, in recent years there has been an increase in the number of small producers servicing the frac sand market due to an increased demand for hydraulic fracturing services.

Intellectual Property

Other than operating licenses for our mining and processing facilities, there are no third-party patents, licenses or franchises material to our business. Our intellectual property primarily consists of trade secrets, know-how and trademarks, including our name “U.S. Silica” and products such as “OTTAWA WHITE.” We strategically rely on trade secrets, rather than patents, to protect our proprietary processes, methods, documentation and other technologies, as well as certain other business information. Patent protection requires a costly and uncertain federal registration process that would place our confidential information in the public domain. Typically, we utilize trade secrets to protect the formulations and processes we use to manufacture our products and to safeguard our proprietary formulations and methods. We believe we can effectively protect our trade secrets indefinitely through the use of confidentiality agreements and other security measures.

Condition of Physical Assets and Insurance

Our business is capital intensive and requires ongoing capital investment for the replacement, modernization and/or expansion of equipment and facilities. For more information, see Item 7, “Management’s Discussion and Analysis of Financial Condition and Results of Operations – Liquidity and Capital Resources”.

We maintain insurance policies against property loss and business interruption and insure against risks that are typical in the operation of our business, in amounts that we believe to be reasonable. Such insurance, however, contains exclusions and limitations on coverage, particularly with respect to environmental liability and political risk. There can be no assurance that claims would be paid under such insurance policies in connection with a particular event. See Item 1A, “Risk Factors”.

Employees

As of December 31, 2013, we employed a workforce of 844 employees, the majority of whom are hourly wage plant workers living in the areas surrounding our mining facilities. The majority of our hourly employees are represented by labor unions that include the Teamsters, United Steelworkers, Paper Allied-Industrial Chemical & Energy, Glass/Molders/Pottery/Plastics and Laborers. We believe that we maintain good relations with our workers and their respective unions and have not experienced any material strikes or work stoppages since 1987.

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Our employees average approximately 12 years of tenure with us, and we have an annual employee turnover rate of 11%. We believe this low turnover rate has directly contributed to improved process efficiencies and safety, which in turn help drive cost reductions. We believe our labor rates compare favorably to other mining and manufacturing facilities in the same geographic areas. We maintain workers’ compensation coverage in amounts required by law and have no material claims pending. We also offer all full-time employees a competitive package of employee benefits, which includes medical, dental, life and disability coverage.

Seasonality

Our business is affected to some extent by seasonal fluctuations in weather that impact our production levels and our customers’ business needs. For example, in the second and third quarters, we sell more commercial silica to our customers in the building products and recreation end markets due to the seasonal rise in construction driven by more favorable weather conditions. Our sales and sometimes our production levels are lower in the first and fourth quarters due to lower market demand and due to our customers in these end markets experiencing slowdowns largely as a result of adverse weather conditions.

Regulation and Legislation

Mining and Workplace Safety

Federal Regulation

The U.S. Mine Safety and Health Administration (“MSHA”) is the primary regulatory organization governing the commercial silica industry. Accordingly, MSHA regulates quarries, surface mines, underground mines and the industrial mineral processing facilities associated with quarries and mines. The mission of MSHA is to administer the provisions of the Federal Mine Safety and Health Act of 1977 and to enforce compliance with mandatory safety and health standards. MSHA works closely with the Industrial Minerals Association, a trade association in which we have a significant leadership role, in pursuing this mission. As part of MSHA’s oversight, representatives perform at least two unannounced inspections annually for each above-ground facility. To date these inspections have not resulted in any citations for material violations of MSHA standards. For additional information regarding mining and workplace safety, including MSHA safety and health violations and assessments in 2013, see Item 4, “Mine Safety Disclosures”.

We also are subject to the requirements of the U.S. Occupational Safety and Health Act (“OSHA”) and comparable state statutes that regulate the protection of the health and safety of workers. In addition, the OSHA Hazard Communication Standard requires that information be maintained about hazardous materials used or produced in operations and that this information be provided to employees, state and local government authorities and the public. OSHA regulates the customers and users of commercial silica and provides detailed regulations requiring employers to protect employees from overexposure to silica bearing dust through the enforcement of permissible exposure limits and the OSHA Hazard Communication Standard.

Internal Controls

We adhere to a strict occupational health program aimed at controlling exposure to silica bearing dust, which includes dust sampling, a respiratory protection program, medical surveillance, training and other components. Our safety program is designed to ensure compliance with the standards of our Occupational Health and Safety Manual and MSHA regulations. For both health and safety issues, extensive training is provided to employees. We have safety committees at our plants made up of salaried and hourly employees. We perform annual internal health and safety audits and conduct annual crisis management drills to test our plants’ abilities to respond to various situations. Health and safety programs are administered by our corporate health and safety department with the assistance of plant Environmental, Health and Safety Coordinators.

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Environmental Matters

We and the commercial silica industry are subject to extensive governmental regulation on, among other things, matters such as permitting and licensing requirements, plant and wildlife protection, hazardous materials, air and water emissions and environmental contamination and reclamation. A variety of state, local and federal agencies enforce this regulation.

Federal Regulation

At the federal level, we may be required to obtain permits under Section 404 of the Clean Water Act from the U.S. Army Corps of Engineers for the discharge of dredged or fill material into waters of the United States, including wetlands and streams, in connection with our operations. We also may be required to obtain permits under Section 402 of the Clean Water Act from the U.S. Environmental Protection Agency (“EPA”) (or the relevant state environmental agency in states where the permit program has been delegated to the state) for discharges of pollutants into waters of the United States, including discharges of wastewater or stormwater runoff associated with construction activities. Failure to obtain these required permits or to comply with their terms could subject us to administrative, civil and criminal penalties as well as injunctive relief.

The U.S. Clean Air Act and comparable state laws regulate emissions of various air pollutants through air emissions permitting programs and the imposition of other requirements. These regulatory programs may require us to install expensive emissions abatement equipment, modify our operational practices and obtain permits for our existing operations, and before commencing construction on a new or modified source of air emissions, such laws may require us to reduce emissions at existing facilities. As a result, we may be required to incur increased capital and operating costs because of these regulations. We could be subject to administrative, civil and criminal penalties as well as injunctive relief for noncompliance with air permits or other requirements of the U.S. Clean Air Act and comparable state laws and regulations.

As part of our operations, we utilize or store petroleum products and other substances such as diesel fuel, lubricating oils and hydraulic fluid. We are subject to applicable requirements regarding the storage, use, transportation and disposal of these substances, including the relevant Spill Prevention, Control and Countermeasure requirements that the EPA imposes on us. Spills or releases may occur in the course of our operations, and we could incur substantial costs and liabilities as a result of such spills or releases, including those relating to claims for damage or injury to property and persons.

Additionally, some of our operations are located on properties that historically have been used in ways that resulted in the release of contaminants, including hazardous substances, into the environment, and we could be held liable for the remediation of such historical contamination. The Comprehensive Environmental Response, Compensation and Liability Act (“CERCLA”), also known as the Superfund law, and comparable state laws impose joint and several liability, without regard to fault or legality of conduct, on classes of persons who are considered to be responsible for the release of hazardous substances into the environment. These persons include the owner or operator of the site where the release occurred and anyone who disposed or arranged for the disposal of a hazardous substance released at the site. Under CERCLA, such persons may be subject to liability for the costs of cleaning up the hazardous substances, for damages to natural resources, and for the costs of certain health studies. In addition, it is not uncommon for neighboring landowners and other third parties to file claims for personal injury and property damage allegedly caused by the hazardous substances released into the environment.

In addition, the Resource Conservation and Recovery Act (“RCRA”) and comparable state statutes regulate the generation, transportation, treatment, storage, disposal and cleanup of hazardous and non-hazardous wastes. Under the auspices of the EPA, the individual states administer some or all of the provisions of RCRA, sometimes in conjunction with their own, more stringent requirements. In the course of our operations, we generate industrial solid wastes that may be regulated as hazardous wastes.

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Our operations may also be subject to broad environmental review under the National Environmental Policy Act (“NEPA”). NEPA requires federal agencies to evaluate the environmental impact of all “major federal actions” significantly affecting the quality of the human environment. The granting of a federal permit for a major development project, such as a mining operation, may be considered a “major federal action” that requires review under NEPA. Therefore, our projects may require review and evaluation under NEPA. As part of this evaluation, the federal agency considers a broad array of environmental impacts, including, among other things, impacts on air quality, water quality, wildlife (including threatened and endangered species), historical and archeological resources, geology, socioeconomics and aesthetics. NEPA also requires the consideration of alternatives to the project. The NEPA review process, especially the preparation of a full environmental impact statement, can be time consuming and expensive. The purpose of the NEPA review process is to inform federal agencies’ decision-making on whether federal approval should be granted for a project and to provide the public with an opportunity to comment on the environmental impacts of a proposed project. While NEPA requires only that an environmental evaluation be conducted and does not mandate a result, a federal agency could decide to deny a permit, or impose certain conditions on its approval, based on its environmental review under NEPA, or a third party may challenge the adequacy of a NEPA review.

Federal agencies granting permits for our operations also must consider impacts to endangered and threatened species and their habitat under the Endangered Species Act. We also must comply with and are subject to liability under the Endangered Species Act, which prohibits and imposes stringent penalties for the harming of endangered or threatened species and their habitat. Federal agencies also must consider a project’s impacts on historic or archeological resources under the National Historic Preservation Act, and we may be required to conduct archeological surveys of project sites and to avoid or preserve historical areas or artifacts.

State and Local Regulation

Because our operations are located in numerous states, we are also subject to a variety of different state and local environmental review and permitting requirements. Some states in which our projects are located or are being developed have state laws similar to NEPA; thus our development of new sites or the expansion of existing sites may be subject to comprehensive state environmental reviews even if they are not subject to NEPA. In some cases, the state environmental review may be more stringent than the federal review. Our operations may require state law based permits in addition to federal permits, requiring state agencies to consider a range of issues, many the same as federal agencies, including, among other things, a project’s impact on wildlife and their habitats, historic and archaeological sites, aesthetics, agricultural operations and scenic areas. Some states also have specific permitting and review processes for commercial silica mining operations, and states may impose different or additional monitoring or mitigation requirements than federal agencies. The development of new sites and our existing operations also are subject to a variety of local environmental and regulatory requirements, including land use, zoning, building and transportation requirements.

As demand for frac sand in the oil and natural gas industry has driven a significant increase in current and expected future production of commercial silica, some local communities have expressed concern regarding silica sand mining operations. These concerns have generally included exposure to ambient silica sand dust, truck traffic, water usage and blasting. In response, certain state and local communities have developed or are in the process of developing regulations or zoning restrictions intended to minimize dust from getting airborne, control the flow of truck traffic, significantly curtail the amount of practicable area for mining activities, provide compensation to local residents for potential impacts of mining activities and, in some cases, ban issuance of new permits for mining activities. To date, we have not experienced any material impact or disruption to our existing mining operations or planned capacity expansions as a result of these types of concerns.

We have a long history of positive engagement with the communities that surround our existing mining operations. We have 11% employee turnover and have had no significant strikes in more than 26 years, evidence of the strong relationship we have with our employees. We believe this strong relationship helps foster good relations with the communities in which we operate. Although additional regulatory requirements could

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negatively impact our business, financial condition and results of operations, we believe our existing operations are less likely to be negatively impacted by virtue of our good community relations.

Planned expansion of our mining and production capacity in new communities could be more significantly impacted by increased regulatory activity. Difficulty or delays in obtaining or inability to obtain new mining permits or increased costs of compliance with future state and local regulatory requirements could have a material negative impact on our ability to grow our business. In an effort to minimize these risks, we continue to be engaged with local communities in order to grow and maintain strong relationships with residents and regulators.

Costs of Compliance

We may incur significant costs and liabilities as a result of environmental, health and safety requirements applicable to our activities. Failure to comply with environmental laws and regulations may result in the assessment of administrative, civil and criminal penalties, imposition of investigatory, cleanup and site restoration costs and liens, the denial or revocation of permits or other authorizations and the issuance of injunctions to limit or cease operations. Compliance with these laws and regulations may also increase the cost of the development, construction and operation of our projects and may prevent or delay the commencement or continuance of a given project. In addition, claims for damages to persons or property may result from environmental and other impacts of our activities.

The process for performing environmental impact studies and reviews for federal, state and local permits for our operations involves a significant investment of time and monetary resources. We cannot control the permit approval process. We cannot predict whether all permits required for a given project will be granted or whether such permits will be the subject of significant opposition. The denial of a permit essential to a project or the imposition of conditions with which it is not practicable or feasible to comply could impair or prevent our ability to develop a project. Significant opposition and delay in the environmental review and permitting process also could impair or delay our ability to develop a project. Additionally, the passage of more stringent environmental laws could impair our ability to develop new operations and have an adverse effect on our financial condition and results of operations.

Availability of Reports; Website Access; Other Information

Our internet address is http://www.ussilica.com. Through “Investor Relations” — “SEC Filings” on our home page, we make available free of charge our Annual Report on Form 10-K, our quarterly reports on Form 10-Q, our proxy statements, our current reports on Form 8-K, SEC Forms 3, 4 and 5 and any amendments to those reports filed or furnished pursuant to Sections 13(a) or 15(d) of the Securities Exchange Act of 1934 as soon as reasonably practicable after we electronically file such material with, or furnish it to, the SEC. Our reports filed with the SEC are also made available to read and copy at the SEC’s Public Reference Room at 100 F Street, N.E., Washington, D.C. 20549. You may obtain information about the Public Reference Room by contacting the SEC at 1-800-SEC-0330. Reports filed with the SEC are also made available on its website at www.sec.gov.

Executive Officers of the Registrant

John P. Blanchard, age 40, has served as our Vice President and General Manager, Industrial and Specialty Products since September 2011. Mr. Blanchard possesses over 17 years’ experience in a variety of industries, including nonwovens, composites, building materials and pharmaceuticals. Prior to joining us, Mr. Blanchard held various positions of increasing responsibility with Johns Manville from 2005 to September 2011, including Global Business Director from December 2010 to September 2011 and Global Business Manager from February 2008 to December 2010. Mr. Blanchard earned a B.S. in Chemical Engineering from Michigan Technological University and an M.B.A. from the University of Michigan.

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Bradford B. Casper, age 39, has served as our Vice President of Strategic Planning since May 2011. Before joining us, Mr. Casper was at Bain & Company, Inc., where he held various positions from 2002 to May 2011 in the United States, Australia and Hong Kong, most recently serving as a Principal from July 2010 to May 2011. Mr. Casper earned a B.S. in Accounting from the University of Illinois at Urbana-Champaign and an M.B.A. from the Wharton School at the University of Pennsylvania.

Christine C. Marshall, age 52, has served as our General Counsel and Corporate Secretary since November 2012. Prior to joining us, Ms. Marshall served as Vice President and General Counsel of the Security Technologies Sector of Ingersoll Rand Company from September 2010 to January 2012. From 2005 to 2010, Ms. Marshall held various positions of increasing responsibility with Tyco International, including General Counsel of Tyco Flow Control Americas from January 2008 to May 2010. Ms. Marshall earned a B.A. degree from Harvard University and a J.D. degree from Georgetown University Law Center.

Donald A. Merril, age 49, has served as our Vice President and Chief Financial Officer since January 2013 and served as our Vice President of Finance from October 2012 until his appointment as Chief Financial Officer. Previously, Mr. Merril had served as Senior Vice President and Chief Financial Officer of Myers Industries Inc. from January 2006 through August 2012. Prior to serving at Myers Industries, Mr. Merril held the role of Vice President and Chief Financial Officer, Rubbermaid Home Products Division at Newell Rubbermaid Inc. from 2003 through 2005. Mr. Merril has a B.S. in Accounting from Miami University.

David D. Murry, age 52, has served as our Vice President of Talent Management and Chief Human Resources Officer since October 2011. Prior to joining us, Mr. Murry was the Director of Human Resources and Talent Management for Arkema, a diversified chemicals company, from October 2005 to October 2011. He has held positions of increasing leadership with Armstrong, Dell, and Alcoa. Mr. Murry oversees our Human Resources, Occupational Health, and Safety team members in the corporate office as well as at all of our operating facilities. Mr. Murry earned a B.S. in Mining Engineering from Texas A&M University and a Master’s of Science in Management from Antioch University.

Bryan A. Shinn, age 52, has served as our President since March 2011 and as our Chief Executive Officer and a member of our Board of Directors (the “Board”) since January 10, 2012. Prior to assuming this position, Mr. Shinn was our Senior Vice President of Sales and Marketing from October 2009 to February 2011. Before joining us, Mr. Shinn was employed by the E. I. du Pont de Nemours and Company from 1983 to September 2009, where he held a variety of key leadership roles in operations, sales, marketing and business management, including Global Business Director and Global Sales Director. Mr. Shinn earned a B.S. in Mechanical Engineering from the University of Delaware. As a result of these and other professional experiences, Mr. Shinn possesses particular knowledge and experience in operations, sales, marketing, management and corporate strategy that strengthen the Board's collective qualifications, skills and experience.

Jason L. Tedrow, age 39, has served as our Vice President of Supply Chain since January 2012. Before joining us, Mr. Tedrow was with Lafarge Cement where he held various distribution and supply chain management roles of increasing responsibility from 2006 through January 2012, most recently serving as the Director of Distribution for Lafarge’s River Business Unit from July 2011 to January 2012. Mr. Tedrow also held various engineering and supply chain management positions with ConAgra Foods from 2000 to January 2006 and The Amway Corporation from 1998 to August 2000. Mr. Tedrow earned a B.S. in Industrial Engineering from Western Michigan University and an M.B.A. from the University of Chicago, Booth School of Business.

Don Weinheimer, age 55, has served as our Vice President and General Manager, Oil & Gas since July 2012. Before joining us, Mr. Weinheimer had served in various executive positions with Key Energy Services since October 2006 including as Senior Vice President, Strategy, Markets and Technology; Senior Vice President of Business Development, Technology and Strategic Planning; Senior Vice President of Product Development, Strategic Planning and Quality; and Senior Vice President, Production Services. Prior to joining Key Energy Services, Mr. Weinheimer held various positions of increasing responsibility with Halliburton Company, a global

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energy services company, since 1981 including as Vice President of Technology Globalization within its Energy Services Group from July 2006 to October 2006 and as Vice President of Innovation and Marketing in its Production Optimization Division from July 2004 to June 2006. Mr. Weinheimer has over 31 years of industry experience, including international operational and business development experience in both the Middle East and Algeria. Mr. Weinheimer earned his B.S. in Agricultural Engineering from Texas A&M University.

Michael L. Winkler, age 49, has served as our Vice President and Chief Operating Officer since December 2013. He served as our Vice President of Operations from June 2011 until December 2013. Before joining us, Mr. Winkler was Vice President of Operations for Campbell Soup Company from August 2007 to June 2011 and held various positions with Mars Inc. from 1996 to August 2007, including Plant Manager—Columbus Plant and Director of Industrial Engineering. Mr. Winkler earned a B.S. in Industrial Engineering from the University of Wisconsin—Platteville and an M.B.A. from the University of North Texas.

Adam S. Yoxtheimer, age 34, joined U.S. Silica in September 2013 as our Vice President and Chief Administrative Officer. Prior to joining us, Mr. Yoxtheimer served as a Principal for Booz & Company in the Energy, Chemical and Utilities practice from May 2007 until September 2013. From 2004 until 2006, Mr. Yoxtheimer held a senior engineering position in the Information Systems & Global Solutions division of Lockheed Martin Corporation. He began his career as a systems engineer at BAE Systems based in Washington, D.C. Mr. Yoxtheimer holds a bachelor’s degree from Princeton University, a master’s degree from University of Virginia and an MBA from the Darden Graduate School of Business at the University of Virginia.

Our operations and financial results are subject to various risks and uncertainties, including those described below and elsewhere in this Annual Report on Form 10-K. You should carefully consider the risk factors set forth below as well as the other information contained in this Annual Report on Form 10-K in connection with evaluating us. Additional risks and uncertainties not currently known to us or that we currently deem to be immaterial may also materially and adversely affect our business, results of operations or financial condition. Certain statements in “Risk Factors” are forward-looking statements.

Risks Related to Our Business

The demand for commercial silica fluctuates, which could adversely affect our results of operations.

Demand in the end markets served by our customers is influenced by many factors, including the following:

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We cannot predict or control the factors that affect demand for our products. Negative developments in the above factors, among others, could cause the demand for commercial silica or other minerals to decline, which could adversely affect our business, financial condition, results of operations, cash flows and prospects.

Our operations are subject to the cyclical nature of our customers’ businesses, and we may not be able to mitigate that risk.

The substantial majority of our sales are to customers in industries that have historically been cyclical, such as glassmaking, building products, foundry and oil and natural gas recovery. During periods of economic slowdown, our customers often reduce their production rates and also reduce capital expenditures and defer or cancel pending projects. Such developments occur even among customers that are not experiencing financial difficulties.

Demand in many of the end markets for commercial silica is driven by the construction and automotive industries. For example, the flat glass market depends on the automotive and commercial and residential construction and remodeling markets. The market for commercial silica used to manufacture building products is driven primarily by demand in the construction markets. The demand for foundry silica depends on the rate of automobile, light truck and heavy equipment production as well as construction. In the automotive industry, North American car and truck production was up 4% in 2013 after being up 17% in 2012, but remains below pre-recession levels. Housing starts in 2013 were approximately 923,400 units, an 18% improvement over 2012 but still only a fraction of the peak rate of 2.1 million units in 2005. The demand for frac sand is driven by demand for oil and natural gas. In periods of lower economic productivity or recession, oil and natural gas prices tend to decrease, as they did during late 2008 and portions of 2009, which, in turn, causes exploration and production companies to reduce their exploration, development, production and well completion activities. The reduced level of such activities could result in a corresponding decline in the demand for frac sand. In addition, given that silica transportation represents one of our customers’ largest costs, if, in response to economic pressures, our customers choose to move their production offshore, the increased logistics costs could reduce demand for our products. Continued weakness in the industries we serve has had, and may in the future have, an adverse effect on sales of our products and our results of operations. A continued or renewed economic downturn in one or more of the industries or geographic regions that we serve, or in the worldwide economy, could cause actual results of operations to differ materially from historical and expected results.

Our operations are subject to operating risks that are often beyond our control and could adversely affect production levels and costs, and such risks may not be covered by insurance.

Our mining, processing and production facilities are subject to risks normally encountered in the commercial silica industry. These risks include:

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Any of these risks could result in damage to, or destruction of, our mining properties or production facilities, personal injury, environmental damage, delays in mining or processing, losses or possible legal liability. Any prolonged downtime or shutdowns at our mining properties or production facilities could have a material adverse effect on us.

Not all of these risks are reasonably insurable, and our insurance coverage contains limits, deductibles, exclusions and endorsements. Our insurance coverage may not be sufficient to meet our needs in the event of loss and any such loss may have a material adverse effect on us.

A significant portion of our sales is generated at three of our plants. Any adverse developments at any of those plants or in the end markets those plants serve could have a material adverse effect on our financial condition and results of operations.

A significant portion of our sales are generated at our plants located in Ottawa, Illinois, Mill Creek, Oklahoma, and Sparta, Wisconsin. These plants represented a combined 63%, 58% and 52% of our total sales volume in 2013, 2012 and 2011, respectively. Any adverse development at these plants or in the end markets these plants serve, including adverse developments due to catastrophic events or weather, decreased demand for commercial silica products, a decrease in the availability of transportation services or adverse developments affecting our customers, could have a material adverse effect on our financial condition and results of operations.

Our business and financial performance depend on the level of activity in the oil and natural gas industries.

Our operations that produce frac sand are materially dependent on the levels of activity in natural gas and oil exploration, development and production. More specifically, the demand for the frac sand we produce is closely related to the number of natural gas and oil wells completed in geological formations where sand-based proppants are used in fracture treatments. These activity levels are affected by both short- and long-term trends in natural gas and oil prices. In recent years, natural gas and oil prices and, therefore, the level of exploration, development and production activity, have experienced significant fluctuations. Worldwide economic, political and military events, including war, terrorist activity, events in the Middle East and initiatives by the Organization of the Petroleum Exporting Countries (“OPEC”), have contributed, and are likely to continue to contribute, to price volatility. Additionally, warmer than normal winters in North America and other weather patterns may adversely impact the short-term demand for natural gas and, therefore, demand for our products. Reduction in demand for natural gas to generate electricity could also adversely impact the demand for frac sand. A prolonged

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reduction in natural gas and oil prices would generally depress the level of natural gas and oil exploration, development, production and well completion activity and result in a corresponding decline in the demand for the frac sand we produce. Such a decline could have a material adverse effect on our results of operations and financial condition. In addition, any future decreases in the rate at which oil and natural gas reserves are discovered or developed, whether due to increased governmental regulation, limitations on exploration and drilling activity or other factors, could have a material adverse effect on our business, even in a stronger natural gas and oil price environment.

We may be adversely affected by decreased demand for frac sand or the development of either effective alternative proppants or new processes to replace hydraulic fracturing.

Frac sand is a proppant used in the completion and re-completion of natural gas and oil wells through hydraulic fracturing. Frac sand is the most commonly used proppant and is less expensive than ceramic proppant, which is also used in hydraulic fracturing to stimulate and maintain oil and natural gas production. A significant shift in demand from frac sand to other proppants, such as ceramic proppants, could have a material adverse effect on our financial condition and results of operations. The development and use of other effective alternative proppants, or the development of new processes to replace hydraulic fracturing altogether, could also cause a decline in demand for the frac sand we produce and could have a material adverse effect on our financial condition and results of operations.

Federal, state and local legislative and regulatory initiatives relating to hydraulic fracturing and the potential for related regulatory action or litigation could result in increased costs and additional operating restrictions or delays for our customers, which could negatively impact our business, financial condition and results of operations.

A significant portion of our business supplies frac sand to hydraulic fracturing operators in the oil and natural gas industry. Although we do not directly engage in hydraulic fracturing activities, our customers purchase our frac sand for use in their hydraulic fracturing operations. Increased regulation of hydraulic fracturing may adversely impact our business, financial condition and results of operations.

The federal Safe Drinking Water Act (the “SDWA”) regulates the underground injection of substances through the Underground Injection Control Program (the “UIC Program”). Hydraulic fracturing generally has been exempt from federal regulation under the UIC Program, and the hydraulic fracturing process has been typically regulated by state or local governmental authorities. The EPA, however, has taken the position that certain aspects of hydraulic fracturing with fluids containing diesel fuel may be subject to regulation under the UIC Program, specifically as “Class II” UIC wells. In February 2014, the EPA released an interpretive memorandum to clarify UIC Program requirements under the SDWA for underground injection of diesel fuels in hydraulic fracturing for oil and gas extraction and issued technical guidance containing recommendations for EPA permit writers to consider in implementing these UIC “Class II” requirements. Among other things, the memorandum and technical guidance clarified that any owner or operator who injects diesel fuels in hydraulic fracturing for oil or gas extraction must obtain a UIC “Class II” permit before injection. The EPA also issued final rules in 2012 that included the first federal air standards for natural gas and oil wells that are hydraulically fractured, along with other requirements for several other sources of pollution in the oil and gas industry that had not been regulated at the federal level. In addition, the EPA has commenced a study of the potential environmental impacts of hydraulic fracturing activities, a committee of the U.S. House of Representatives (the “House”) conducted an investigation of hydraulic fracturing practices and a subcommittee of the Secretary of Energy Advisory Board (the “SEAB”) of the U.S. Department of Energy was tasked with recommending steps to improve the safety and environmental performance of hydraulic fracturing. As part of these studies, the EPA, the House committee and the SEAB subcommittee requested that certain companies provide them with information concerning the chemicals used in the hydraulic fracturing process. These studies could potentially spur initiatives to further regulate hydraulic fracturing under the SDWA or otherwise. The SEAB subcommittee issued a preliminary report in August 2011 and a final report in November 2011 recommending, among other things,

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measures to improve and protect air and water quality, improvements in communication among state and federal regulators, elimination of diesel fuel in shale gas production, disclosure of fracturing fluid composition and the creation of a publicly accessible database organizing all publicly disclosed information with respect to hydraulic fracturing operations. Legislation has been introduced before the U.S. Congress to provide for federal regulation of hydraulic fracturing under the SDWA and to require disclosure of the chemicals used in the hydraulic fracturing process. If this or similar legislation becomes law, the legislation could establish an additional level of federal regulation that may lead to additional permitting requirements or other operating restrictions, making it more difficult to complete natural gas and oil wells in shale formations. This could increase our customers’ costs of compliance and doing business or otherwise adversely affect the hydraulic fracturing services they perform, which may negatively impact demand for our frac sand products.

In addition, the federal Bureau of Land Management (the “BLM”) and various state, local and foreign governments have implemented, or are considering, increased regulatory oversight of hydraulic fracturing through additional permitting requirements, operational restrictions, disclosure requirements and temporary or permanent bans on hydraulic fracturing in certain areas such as environmentally sensitive watersheds. For example, Vermont banned hydraulic fracturing in the state in 2012 and certain states such as New York and New Jersey issued moratoriums on hydraulic fracturing while they considered studies of and regulations regarding hydraulic fracturing, although New Jersey’s moratorium expired in 2013. A number of local municipalities across the United States have instituted measures resulting in temporary or permanent bans on or otherwise limiting or delaying hydraulic fracturing in their jurisdictions. Such moratoriums and bans could make it more difficult to conduct hydraulic fracturing operations and increase our customers’ cost of doing business, which could negatively impact demand for our frac sand products. The BLM also proposed and is in the process of reconsidering regulations requiring disclosure of chemicals used in the hydraulic fracturing process both before and after any drilling on federal public land, and Arkansas, Colorado, Idaho, Illinois, Indiana, Louisiana, Michigan, Mississippi, Montana, New Mexico, North Dakota, Ohio, Oklahoma, Pennsylvania, South Dakota, Tennessee, Texas, Utah, West Virginia and Wyoming have enacted legislation or issued regulations which impose various disclosure requirements on hydraulic fracturing operators. The availability of information regarding the constituents of hydraulic fracturing fluids could make it easier for third parties opposing the hydraulic fracturing process to initiate individual or class action legal proceedings based on allegations that specific chemicals used in the hydraulic fracturing process could adversely affect groundwater and drinking water supplies or otherwise cause harm to human health or the environment. Moreover, disclosure to third parties or to the public, even if inadvertent, of our customers’ proprietary chemical formulas could diminish the value of those formulas and result in competitive harm to our customers, which could indirectly impact our business, financial condition and results of operations.

The adoption of new laws or regulations at the federal, state, local or foreign levels imposing reporting obligations on, or otherwise limiting or delaying, the hydraulic fracturing process could make it more difficult to complete natural gas and oil wells in shale formations, increase our customers’ costs of compliance and doing business and otherwise adversely affect the hydraulic fracturing services they perform, which could negatively impact demand for our frac sand products. In addition, heightened political, regulatory and public scrutiny of hydraulic fracturing practices could potentially expose us or our customers to increased legal and regulatory proceedings, and any such proceedings could be time-consuming, costly or result in substantial legal liability or significant reputational harm. Any such developments could have a material adverse effect on our business, financial condition and results of operations, whether directly or indirectly. For example, we could be directly affected by adverse litigation involving us, or indirectly affected if the cost of compliance limits the ability of our customers to operate in the geographic areas we serve.

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Our operations are dependent on our rights and ability to mine our properties and on our having renewed or received the required permits and approvals from governmental authorities and other third parties.

We hold numerous governmental, environmental, mining and other permits, water rights and approvals authorizing operations at each of our facilities. A decision by a governmental agency or other third party to deny or delay issuing a new or renewed permit or approval, or to revoke or substantially modify an existing permit or approval, could have a material adverse effect on our ability to continue operations at the affected facility. Expansion of our existing operations is also predicated on securing the necessary environmental or other permits, water rights or approvals, which we may not receive in a timely manner or at all. In addition, our facilities are located near existing and proposed third-party industrial operations that could affect our ability to fully extract, or the manner in which we extract, the mineral deposits to which we have mining rights.

Title to, and the area of, mineral properties and water rights may also be disputed. Mineral properties sometimes contain claims or transfer histories that examiners cannot verify. A successful claim that we do not have title to one or more of our properties or lack appropriate water rights could cause us to lose any rights to explore, develop and extract any minerals on that property, without compensation for our prior expenditures relating to such property. Our business may suffer a material adverse effect in the event one or more of our properties are determined to have title deficiencies.

In some instances, we have received access rights or easements from third parties, which allow for a more efficient operation than would exist without the access or easement. A third party could take action to suspend the access or easement, and any such action could be materially adverse to our results of operations or financial condition.

We may not be able to successfully implement our capacity expansion plans within our current timetable, the actual costs of the capacity expansion may exceed our current estimated costs and we may not be able to secure demand for the incremental production capacity. In addition, actual operating costs once we have completed the capacity expansion may be higher than anticipated.

In 2013, our new resin-coated sand facility became fully operational, with capacity to resin coat up to 400 million pounds of sand annually and our Sparta, Wisconsin facility became fully operational with an annual raw sand production capacity of 1,700,000 tons. We also made an initial investment in a new Greenfield site near Utica, Illinois, which we expect to become fully operational by the end of the second quarter of 2014 and to have an annual capacity of approximately 1,500,000 tons of raw frac sand. In addition, we are evaluating the potential development of a Greenfield project in Eau Claire County, Wisconsin, which, depending on market conditions, could become operational as early as late 2015 and potentially add 3,000,000 tons of annual frac sand capacity.

Under our current business plan, we expect to fund our expansion plan through a combination of cash on our balance sheet and cash generated from our operations. If the assumptions on which we based our estimated capital expenditures change or are inaccurate, we may require additional funding. Such funding may not be available on terms acceptable to us, or at all. Moreover, actual operating costs once we have completed the capacity expansion may be higher than initially anticipated. We also have not secured off-take commitments for the incremental production from our capacity expansion plans, and we may not be able to secure adequate demand for the incremental production. Furthermore, substantial investments in transportation infrastructure have been and will be required to effectively execute the capacity expansion, and we may not be successful in expanding our logistical capabilities to accommodate the additional production capacity.

Any failure to successfully implement our capacity expansion plans due to an inability to obtain necessary permits, insufficient funding, delays, unanticipated costs or other factors, or failure to realize the anticipated benefits of our capacity expansion plans, including securing demand for the incremental production, could have a material adverse effect on our business, financial condition and results of operations.

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Our future performance will depend on our ability to succeed in competitive markets, and on our ability to appropriately react to potential fluctuations in demand for and supply of our products.

We operate in a highly competitive market that is characterized by a small number of large, national producers and a larger number of small, regional or local producers. Competition in the industry is based on price, consistency and quality of product, site location, distribution capability, customer service, reliability of supply, breadth of product offering and technical support. As transportation costs are a significant portion of the total cost to customers of commercial silica—in many instances transportation costs can represent more than 50% of delivered cost—the commercial silica market is typically local, and competition from beyond the local area is limited. Notable exceptions to this are the frac sand and fillers and extenders markets, where certain product characteristics are not available in all deposits and not all plants have the requisite processing capabilities, necessitating that some products be shipped for extended distances.

We compete with large, national producers such as Unimin Corporation, Fairmount Minerals, Ltd., Badger Mining Corporation and Premier Silica. Our larger competitors may have greater financial and other resources than we do, may develop technology superior to ours or may have production facilities that are located closer to key customers than ours.

Because the markets for our products are typically local, we also compete with smaller, regional or local producers. For instance, in recent years there has been an increase in the number of small producers servicing the frac sand market due to an increased demand for hydraulic fracturing services. Should the demand for hydraulic fracturing services decrease or the supply of frac sand available in the market increase, prices in the frac sand market could materially decrease as less-efficient producers exit the market, selling frac sand at below market prices. In addition, oil and natural gas exploration and production companies and other providers of hydraulic fracturing services could acquire their own frac sand reserves, expand their existing frac sand production capacity or otherwise fulfill their own proppant requirements and existing or new frac sand producers could add to or expand their frac sand production capacity, which would negatively impact demand for our frac sand products. We may not be able to compete successfully against either our larger or smaller competitors in the future, and competition could have a material adverse effect on our business, financial condition, results of operations, cash flows and prospects.

A large portion of our sales is generated by our top ten customers, and the loss of, or a significant reduction in, purchases by our largest customers could adversely affect our operations.

Our top ten customers made up 52%, 37% and 44% of our total sales revenue during the years ended December 31, 2013, 2012, and 2011, respectively, with no single customer accounting for more than 10% of the total sales revenue in any given year. During 2013, we had long-term, competitively-bid supply contracts with seven customers in the oil and gas proppants end market, all of which were among our top ten overall customers, including our top customer for 2013. These agreements have initial terms expiring between 2013 and 2016. As of February 26, 2014, we maintained long-term supply contracts with five customers, all of which were among our top ten overall customers. While some of our largest customers have entered into supply contracts with us, these customers may not continue to purchase the same levels of our commercial silica products in the future due to a variety of reasons, contract requirements notwithstanding. For example, some of our top customers could go out of business or, alternatively, be acquired by other companies that purchase the same products and services provided by us from other third-party providers. Our customers could also seek to capture and develop their own sources of commercial silica. If any of our major customers substantially reduces or altogether ceases purchasing our commercial silica products, we could suffer a material adverse effect on our business, financial condition, results of operations, cash flows and prospects.

In addition, the long-term supply agreements we have may negatively impact our results of operations. Certain of our long-term agreements are for sales at fixed prices that are adjusted only for certain cost increases. As a result, in periods with increasing prices, our sales could grow at a slower rate than industry spot prices.

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Increasing costs or a lack of dependability or availability of transportation services or infrastructure could have an adverse effect on our ability to deliver products at competitive prices.

Because of the relatively low cost of producing commercial silica, transportation and handling costs tend to be a significant component of the total delivered cost of sales. The high relative cost of transportation tends to favor manufacturers located in close proximity to the customer. In addition, as we continue to expand our commercial silica production, we will need increased transportation services, including rail cars. We contract with truck, rail and barge services to move commercial silica from our production facilities to distribution outlets and our customers, and increased costs under these contracts could adversely affect our results of operations if we are unable to pass these costs on to our customers. In addition, we bear the risk of non-delivery under our customer contracts. In certain instances we commit to deliver products to our customers prior to production, under penalty of nonperformance. Labor disputes, derailments, adverse weather conditions or other environmental events, an increasingly tight railcar leasing market and changes to rail freight systems could interrupt or limit available transportation services. A significant increase in transportation service rates, a reduction in the dependability or availability of transportation services or relocation of our customers’ businesses to areas farther from our plants could impair our ability to deliver our products economically to our customers and to expand our markets.

Seasonal and severe weather conditions could have a material adverse impact on our business.

Our business could be materially adversely affected by weather conditions. Severe weather conditions may affect our customers’ operations, thus reducing their need for our products, as was the case in December 2013. Weather conditions may impact our operations, resulting in weather-related damage to our facilities and equipment or an inability to deliver equipment, personnel and products to job sites in accordance with contract schedules. In addition, the EPA has stated that climate change may lead to the increased frequency and severity of extreme weather events. Any such interference with our operations could force us to delay or curtail services and potentially breach our contractual obligations or result in a loss of productivity and an increase in our operating costs.

Our production process consumes large amounts of natural gas and electricity. An increase in the price or a significant interruption in the supply of these or any other energy sources could have a material adverse effect on our financial condition or results of operations.

Energy costs, primarily natural gas and electricity, represented approximately 5% of our total sales in 2013. Natural gas is the primary fuel source used for drying in the commercial silica production process and, as such, our profitability is impacted by the price and availability of natural gas we purchase from third parties. The price and supply of natural gas are unpredictable and can fluctuate significantly based on international, political and economic circumstances, as well as other events outside our control, such as changes in supply and demand due to weather conditions, actions by OPEC and other oil and natural gas producers, regional production patterns and environmental concerns. In addition, potential climate change regulations or carbon or emissions taxes could result in higher production costs for energy, which may be passed on to us in whole or in part. In the past, the price of natural gas has been extremely volatile, and we expect this volatility to continue. For example, during the year ended December 31, 2013, the monthly closing price of natural gas ranged from a high of $4.15 per million British Thermal Units (“BTUs”) to a low of $3.23 per million BTUs. In order to manage this risk, we may hedge natural gas prices through the use of derivative financial instruments, such as forwards, swaps and futures. However, these measures carry risk (including nonperformance by counterparties) and do not in any event entirely eliminate the risk of decreased margins as a result of natural gas price increases. A significant increase in the price of energy that is not recovered through an increase in the price of our products or covered through our hedging arrangements or an extended interruption in the supply of natural gas or electricity to our production facilities could have a material adverse effect on our business, financial condition, results of operations, cash flows and prospects.

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Increases in the price of diesel fuel may adversely affect our results of operations.

Diesel fuel costs generally fluctuate with increasing and decreasing world crude oil prices, and accordingly are subject to political, economic and market factors that are outside of our control. Our operations are dependent on earthmoving equipment, railcars and tractor trailers, and diesel fuel costs are a significant component of the operating expense of these vehicles. We use earthmoving equipment in our mining operations, and we ship the vast majority of our products by either railcar or tractor trailer. To the extent that we perform these services with equipment that we own, we are responsible for buying and supplying the diesel fuel needed to operate these vehicles. To the extent that these services are provided by independent contractors, we may be subject to fuel surcharges that attempt to recoup increased diesel fuel expenses. To the extent we are unable to pass along increased diesel fuel costs to our customers, our results of operations could be adversely affected.

Diminished access to water may adversely affect our operations.

The mining and processing activities in which we engage at a number of our facilities require significant amounts of water, and some of our facilities are located in areas that are water-constrained. We have obtained water rights that we currently use to service the activities on our various properties, and we plan to obtain all required water rights to service other properties we may develop or acquire in the future. However, the amount of water that we are entitled to use pursuant to our water rights must be determined by the appropriate regulatory authorities in the jurisdictions in which we operate. Such regulatory authorities may amend the regulations regarding such water rights, increase the cost of maintaining such water rights or eliminate our current water rights, and we may be unable to retain all or a portion of such water rights. For instance, there are proposed regulations reducing water rights per acre for the aquifer accessed by our Mill Creek, Oklahoma facility. These new regulations, which could also affect local municipalities and other industrial operations, could have a material adverse effect on our operating costs and effectiveness if implemented. Such changes in laws, regulations or government policy and related interpretations pertaining to water rights may alter the environment in which we do business, which may negatively affect our financial condition and results of operations.

Title to, and the area of, water rights may also be disputed, including by Native American tribes asserting historical water rights. A successful claim that we lack appropriate water rights on one or more of our properties could cause us to lose any rights to explore, develop and operate mines on that property. Any decrease or disruption in our water rights or available water supply as a result of any of the above factors may adversely affect our operations.

The manufacture of resin-coated sand is a new process for us, and failure to effectively integrate this new process with our existing processes could have a material adverse effect on our financial condition and results of operations.

In 2013, our resin-coating facility in Rochelle, Illinois that produces resin-coated sand, which is a higher-strength alternative to traditional frac sand and involves a manufacturing process with which we are relatively inexperienced, became fully operational. If we are unable to operate this facility effectively or to secure adequate, cost-effective supply commitments for the raw materials associated with resin-coated sand, our ability to sell this product to the marketplace may be adversely impacted. In addition, there are attendant risks of market acceptance and product performance that could result in less demand than anticipated and our having excess capacity. A lack of sales of resin-coated sand could have a material adverse effect on our financial condition and results of operations.

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If we cannot successfully complete acquisitions or integrate acquired businesses, our growth may be limited and our financial condition may be adversely affected.

Our business strategy includes supplementing internal growth by pursuing acquisitions of complementary businesses. Any acquisition involves potential risks, including, among other things:

If we cannot successfully complete acquisitions or integrate acquired businesses, our growth may be limited and our financial condition may be adversely affected.

We will be required to make substantial capital expenditures to maintain, develop and increase our asset base. The inability to obtain needed capital or financing on satisfactory terms, or at all, could have an adverse effect on our growth and profitability.

Although we currently use a significant amount of our cash reserves and cash generated from our operations to fund the maintenance and development of our existing mineral reserves and our acquisitions of new mineral reserves, we may depend on the availability of credit to fund future capital expenditures. Our ability to obtain bank financing or to access the capital markets for future equity or debt offerings may be limited by our financial condition at the time of any such financing or offering, the covenants contained in our existing credit facilities or future debt agreements, adverse market conditions or other contingencies and uncertainties that are beyond our control. Our failure to obtain the funds necessary to maintain, develop and increase our asset base could adversely impact our growth and profitability.

Even if we are able to obtain financing or access the capital markets, incurring additional debt may significantly increase our interest expense and financial leverage, and our level of indebtedness could restrict our ability to fund future development and acquisition activities. In addition, the issuance of additional common stock in an equity offering may result in significant stockholder dilution.

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Our substantial indebtedness and pension obligations could adversely affect our financial flexibility and our competitive position.

We have, and we will continue to have, a significant amount of indebtedness. As of December 31, 2013, we had $371.5 million of outstanding indebtedness. Under our senior secured credit facility, as of December 31, 2013, we had a $50 million line-of-credit, of which $9.0 million is being used for outstanding letters of credit, leaving $41.0 million of borrowing availability. Our substantial level of indebtedness increases the risk that we may be unable to generate cash sufficient to pay amounts due in respect of our indebtedness. We also have, and will continue to have, significant pension obligations. As of December 31, 2013, our unfunded pension obligations totaled $14.5 million. Our substantial indebtedness and pension obligations could have other important consequences to you and significant effects on our business. For example, they could:

Our senior secured credit facility contains certain restrictions and financial covenants that may restrict our business and financing activities

Our existing senior secured credit facility contains, and any future financing agreements that we may enter into will likely contain, operating and financial restrictions and covenants that may restrict our ability to finance future operations or capital needs or to engage in, expand or pursue our business activities.

Our ability to comply with these restrictions and covenants is uncertain and will be affected by the levels of cash flow from our operations and events or circumstances beyond our control. If market or other economic conditions deteriorate, our ability to comply with these covenants may be impaired. If we violate any of the restrictions, covenants, ratios or tests in our senior secured credit facility, a significant portion of our indebtedness may become immediately due and payable and our lenders’ commitment to make further loans to us may terminate. We might not have, or be able to obtain, sufficient funds to make these accelerated payments. In addition, our obligations under our senior secured credit facility are secured by substantially all of our assets, and if we are unable to repay our indebtedness under our senior secured credit facility, the lenders could seek to foreclose on our assets.

We may incur substantial debt in the future to enable us to maintain or increase our production levels and to otherwise pursue our business plan. This debt may impair our ability to operate our business.

Our business plan requires a significant amount of capital expenditures to maintain and grow our production levels. If commercial silica prices were to decline for an extended period of time, if the costs of our acquisition and development operations were to increase substantially or if other events were to occur which reduced our sales or increased our costs, we may be required to borrow significant amounts in the future to enable us to

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finance the expenditures necessary to replace the reserves we produce. The cost of the borrowings and our obligations to repay the borrowings could have important consequences to us, including:

Our ability to service our indebtedness will depend on, among other things, our future financial and operating performance, which will be affected by prevailing economic conditions and financial, business, regulatory and other factors, some of which are beyond our control. If our operating results are not sufficient to service our current or future indebtedness, we will be forced to take actions such as reducing or delaying business activities, acquisitions, investments and/or capital expenditures; selling assets; restructuring or refinancing our indebtedness; or seeking additional equity capital or bankruptcy protection. We may not be able to affect any of these remedies on satisfactory terms or at all.

Inaccuracies in our estimates of mineral reserves and resource deposits could result in lower than expected sales and higher than expected costs.

We base our mineral reserve and resource estimates on engineering, economic and geological data assembled and analyzed by our engineers and geologists, which are reviewed periodically by outside firms. However, commercial silica reserve estimates are necessarily imprecise and depend to some extent on statistical inferences drawn from available drilling data, which may prove unreliable. There are numerous uncertainties inherent in estimating quantities and qualities of commercial silica reserves and non-reserve commercial silica deposits and costs to mine recoverable reserves, including many factors beyond our control. Estimates of economically recoverable commercial silica reserves necessarily depend on a number of factors and assumptions, all of which may vary considerably from actual results, such as:

Any inaccuracy in our estimates related to our mineral reserves and non-reserve mineral deposits could result in lower than expected sales and higher than expected costs.

A shortage of skilled labor together with rising labor costs in the mining industry may further increase operating costs, which could adversely affect our results of operations.

Efficient mining using modern techniques and equipment requires skilled laborers, preferably with several years of experience and proficiency in multiple mining tasks, including processing of mined minerals. If the shortage of experienced labor continues or worsens or if we are unable to train the necessary number of skilled

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laborers, there could be an adverse impact on our labor productivity and costs and our ability to expand production.

As a result of current market conditions and the high demand for skilled labor in certain regions in which we operate, we are experiencing a record level of labor costs, and we expect the cost of labor to increase in the future. If the prices for our products decrease in the future, labor costs may not be commensurately reduced.

Our business may suffer if we lose, or are unable to attract and retain, key personnel.

We depend to a large extent on the services of our senior management team and other key personnel. Members of our senior management and other key employees have extensive experience and expertise in evaluating and analyzing industrial mineral properties, maximizing production from such properties, marketing industrial mineral production and developing and executing financing and hedging strategies. Competition for management and key personnel is intense, and the pool of qualified candidates is limited. The loss of any of these individuals or the failure to attract additional personnel, as needed, could have a material adverse effect on our operations and could lead to higher labor costs or the use of less-qualified personnel. In addition, if any of our executives or other key employees were to join a competitor or form a competing company, we could lose customers, suppliers, know-how and key personnel. We do not maintain key-man life insurance with respect to any of our employees. Our success will be dependent on our ability to continue to attract, employ and retain highly skilled personnel.

Our profitability could be negatively affected if we fail to maintain satisfactory labor relations.

As of December 31, 2013, various labor unions represented approximately 47% of our employees. If we are unable to renegotiate acceptable collective bargaining agreements with these labor unions in the future, we could experience, among other things, strikes, work stoppages or other slowdowns by our workers and increased operating costs as a result of higher wages, health care costs or benefits paid to our employees. An inability to maintain good relations with our workforce could cause a material adverse effect on our business and results of operations.

We rely upon trade secrets and contractual restrictions, and not patents, to protect our proprietary rights. Failure to protect our intellectual property rights may undermine our competitive position, and protecting our rights or defending against third-party allegations of infringement may be costly.

Our commercial success depends on our proprietary information and technologies, know-how and other intellectual property. Because of the technical nature of our business, we rely on trade secrets, trademarks and contractual restrictions to protect our intellectual property rights and currently do not hold any patents related to our business. The measures we take to protect our trade secrets and other intellectual property rights may be insufficient. Failure to protect, monitor and control the use of our existing intellectual property rights could cause us to lose our competitive advantage and incur significant expenses. It is possible that our competitors or others could independently develop the same or similar technologies or otherwise obtain access to our unpatented technologies. In such case, our trade secrets would not prevent third parties from competing with us. As a result, our results of operations may be adversely affected. Furthermore, third parties or employees may infringe or misappropriate our proprietary technologies or other intellectual property rights, which could also harm our business and results of operations. Policing unauthorized use of intellectual property rights can be difficult and expensive, and adequate remedies may not be available.

In addition, third parties may claim that our products infringe or otherwise violate their patents or other proprietary rights and seek corresponding damages or injunctive relief. Defending ourselves against such claims, with or without merit, could be time-consuming and result in costly litigation. An adverse outcome in any such litigation could subject us to significant liability to third parties (potentially including treble damages) or temporary or permanent injunctions prohibiting the manufacture or sale of our products, the use of our

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technologies or the conduct of our business. Any adverse outcome could also require us to seek licenses from third parties (which may not be available on acceptable terms, or at all) or to make substantial one-time or ongoing royalty payments. Protracted litigation could also result in our customers or potential customers deferring or limiting their purchase or use of our products until resolution of such litigation. In addition, we may not have insurance coverage in connection with such litigation and may have to bear all costs arising from any such litigation to the extent we are unable to recover them from other parties. Any of these outcomes could have a material adverse effect on our business, financial condition, results of operations, cash flows and prospects.

We may have to utilize significant cash to meet our unfunded pension obligations and post-retirement health care liabilities and these obligations are subject to increase.

Many of our employees participate in our defined benefit pension plans. In 2013, we made payments totaling $2.3 million toward reducing the unfunded liability of our defined benefit pension plans. Declines in interest rates or the market values of the securities held by the plans, or other adverse changes, could materially increase the underfunded status of our plans and affect the level and timing of required cash contributions. To the extent we use cash to reduce these unfunded liabilities, the amount of cash available for our working capital needs would be reduced. In addition, under the Employee Retirement Income Security Act of 1974, as amended (“ERISA”), the Pension Benefit Guaranty Corporation (“PBGC”) has the authority to institute proceedings to terminate a pension plan if (1) the plan has not met the minimum funding requirements, (2) the plan cannot pay current benefits when due, (3) a lump sum payment has been made to a participant who is a substantial owner of the sponsoring company (and certain other technical conditions exist) or (4) the loss to the PBGC is reasonably expected to increase unreasonably over time if the plan is not terminated. In the event our tax-qualified pension plans are terminated by the PBGC, we could be liable to the PBGC for the underfunded amount, which could trigger default provisions in our credit facilities. As of December 31, 2013, our pension obligation was $99.8 million (with plan assets of $85.4 million). The amount of cash ultimately required to fund these obligations will vary based on a number of factors including future return on assets, mortality rates and other such actuarial assumptions. Based on current assumptions, we expect to pay $4.6 million in the year 2014, a total of $8.5 million for the two-year period from 2015 through 2016 and a total of $5.4 million for the two-year period from 2017 through 2018.

We also have a post-retirement health and life insurance plan for many of our employees. The post-retirement benefit plan is unfunded. We derive post-retirement benefit expense from an actuarial calculation based on the provisions of the plan and a number of assumptions provided by us including information about employee demographics, retirement age, future health care costs, turnover, mortality, discount rate, amount and timing of claims and a health care inflation trend rate. Our post-retirement healthcare obligations were $22.3 million as of December 31, 2013. Based on current assumptions, we expect to pay $1.4 million in the year 2014, a total of $2.8 million for the two-year period from 2015 through 2016, a total of $3.0 million for the two-year period from 2017 through 2018 and a total of $15.1 million thereafter. See “Management’s Discussion and Analysis of Financial Condition and Results of Operations—Contractual Obligations.”

Failure to maintain effective quality control systems at our mining, processing and production facilities could have a material adverse effect on our business and operations.

The performance, quality and safety of our products are critical to the success of our business. These factors depend significantly on the effectiveness of our quality control systems, which, in turn, depends on a number of factors, including the design of our quality control systems, our quality-training program and our ability to ensure that our employees adhere to the quality control policies and guidelines. Any significant failure or deterioration of our quality control systems could have a material adverse effect on our business, financial condition, results of operations and reputation.

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Our sales and profitability fluctuate on a seasonal basis and are affected by a variety of other factors.

Our sales and profitability are affected by a variety of factors, including actions of competitors, changes in general economic conditions, weather conditions and seasonal periods. As a result, our results of operations fluctuate on a quarterly basis and relative to corresponding periods in prior years, and any of these factors could adversely affect our business and cause our results of operations to decline. For example, we sell more of our products in the second and third quarters in the building products and recreation end markets due to the seasonal rise in construction driven by more favorable weather conditions. We sell fewer of our products in the first and fourth quarters due to reduced construction and recreational activity largely as a result of adverse weather conditions. Any unanticipated decrease in demand for our products during the second and third quarters could have a material adverse effect on our sales and profitability.

We may be subject to interruptions or failures in our information technology systems.

We rely on sophisticated information technology systems and infrastructure to support our business, including process control technology. Any of these systems may be susceptible to outages due to fire, floods, power loss, telecommunications failures and similar events. The failure of any of our information technology systems may cause disruptions in our operations, which could adversely affect our sales and profitability.

A terrorist attack or armed conflict could harm our business.

Terrorist activities, anti-terrorist efforts and other armed conflicts involving the United States could adversely affect the U.S. and global economies and could prevent us from meeting financial and other obligations. We could experience loss of business, delays or defaults in payments from payors or disruptions of fuel supplies and markets if pipelines, production facilities, processing plants or refineries are direct targets or indirect casualties of an act of terror or war. Such activities could reduce the overall demand for oil and natural gas, which, in turn, could also reduce the demand for our products and services. Terrorist activities and the threat of potential terrorist activities and any resulting economic downturn could adversely affect our results of operations, impair our ability to raise capital or otherwise adversely impact our ability to realize certain business strategies.

If we fail to maintain adequate internal controls over financial reporting, we may not be able to report our financial results in a timely and reliable manner, which could harm our business and impact the value of our common stock.

We depend on our ability to produce accurate and timely financial statements in order to run our business. If we fail to do so, our business could be negatively affected and our independent registered public accounting firm may be unable to attest to the accuracy of our financial statements and effectiveness of our internal controls.

If we fail to maintain effective internal controls in the future, it could result in a material misstatement of our financial statements that would not be prevented or detected on a timely basis, which could cause investors to lose confidence in our financial information or cause our stock price to decline.

Risks Related to Environmental, Mining and Other Regulation

We and our customers are subject to extensive environmental and health and safety regulations that impose, and will continue to impose, significant costs and liabilities. In addition, future regulations, or more stringent enforcement of existing regulations, could increase those costs and liabilities, which could adversely affect our results of operations.

We are subject to a variety of federal, state and local regulatory environmental requirements affecting the mining and mineral processing industry, including among others, those relating to employee health and safety, environmental permitting and licensing, air and water emissions, greenhouse gas emissions, water pollution, waste management, remediation of soil and groundwater contamination, land use, reclamation and restoration of

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properties, hazardous materials and natural resources. These laws, regulations and permits have had, and will continue to have, a significant effect on our business. Some environmental laws impose substantial penalties for noncompliance, and others, such as CERCLA, impose strict, retroactive and joint and several liability for the remediation of releases of hazardous substances. Liability under CERCLA, or similar state and local laws, may be imposed as a result of conduct that was lawful at the time it occurred or for the conduct of, or conditions caused by, prior operators or other third parties. Failure to properly handle, transport, store or dispose of hazardous materials or otherwise conduct our operations in compliance with environmental laws could expose us to liability for governmental penalties, cleanup costs and civil or criminal liability associated with releases of such materials into the environment, damages to property or natural resources and other damages, as well as potentially impair our ability to conduct our operations. In addition, future environmental laws and regulations could restrict our ability to expand our facilities or extract our mineral deposits or could require us to acquire costly equipment or to incur other significant expenses in connection with our business. Future events, including changes in any environmental requirements (or their interpretation or enforcement) and the costs associated with complying with such requirements, could have a material adverse effect on us.

Any failure by us to comply with applicable environmental laws and regulations may cause governmental authorities to take actions that could adversely impact our operations and financial condition, including:

Moreover, environmental requirements, and the interpretation and enforcement thereof, change frequently and have tended to become more stringent over time. For example, greenhouse gas emission regulation is becoming more rigorous. We expect to be required to report annual greenhouse gas emissions from our operations to the EPA, and additional greenhouse gas emission related requirements at the supranational, federal, state, regional and local levels are in various stages of development. The U.S. Congress has considered, and may adopt in the future, various legislative proposals to address climate change, including a nationwide limit on greenhouse gas emissions. In addition, the EPA has issued regulations, including the “Tailoring Rule,” that subject greenhouse gas emissions from certain stationary sources to the Prevention of Significant Deterioration and Title V provisions of the federal Clean Air Act. Any such regulations could require us to modify existing permits or obtain new permits, implement additional pollution control technology, curtail operations or increase significantly our operating costs. Any regulation of greenhouse gas emissions, including, for example, through a cap-and-trade system, technology mandate, emissions tax, reporting requirement or other program, could adversely affect our business, financial condition, reputation, operating performance and product demand.

In addition to environmental regulation, we are subject to laws and regulations relating to human exposure to crystalline silica. Several federal and state regulatory authorities, including the U.S. Mining Safety and Health Administration and the U.S. Occupational Safety and Health Administration, may continue to propose changes in their regulations regarding workplace exposure to crystalline silica, such as permissible exposure limits and required controls and personal protective equipment. For instance, in August 2013, OSHA proposed regulations that would reduce permissible exposure limits to 50 micrograms of respirable crystalline silica per cubic meter of air, averaged over an 8-hour day. Both the North American Industrial Mining Association and the National Industrial Sand Association, both of which we are a member, track silicosis-related issues and aim to work with government policymakers in crafting such regulations.

We may not be able to comply with any new laws and regulations that are adopted, and any new laws and regulations could have a material adverse effect on our operating results by requiring us to modify our operations or equipment or shut down some or all of our plants. Additionally, our customers may not be able to comply with

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any new laws and regulations, and any new laws and regulations could have a material adverse effect on our customers by requiring them to shut down old plants or to relocate plants to locations with less stringent regulations farther away from our facilities. We cannot at this time reasonably estimate our costs of compliance or the timing of any costs associated with any new laws and regulations, or any material adverse effect that any new standards will have on our customers and, consequently, on our operations.

We are subject to various lawsuits relating to the actual or alleged exposure of persons to silica. See “—Risks Related to Our Business—Silica-related health issues and litigation could have a material adverse effect on our business, reputation or results of operations.”

We are subject to the Federal Mine Safety and Health Act of 1977, which imposes stringent health and safety standards on numerous aspects of our operations.

Our operations are subject to the Federal Mine Safety and Health Act of 1977, as amended by the Mine Improvement and New Emergency Response Act of 2006, which imposes stringent health and safety standards on numerous aspects of mineral extraction and processing operations, including the training of personnel, operating procedures, operating equipment and other matters. Our failure to comply with such standards, or changes in such standards or the interpretation or enforcement thereof, could have a material adverse effect on our business and financial condition or otherwise impose significant restrictions on our ability to conduct mineral extraction and processing operations.

Silica-related health issues and litigation could have a material adverse effect on our business, reputation or results of operations.

The inhalation of respirable crystalline silica is associated with the lung disease silicosis. There is recent evidence of an association between crystalline silica exposure or silicosis and lung cancer and a possible association with other diseases, including immune system disorders such as scleroderma. These health risks have been, and may continue to be, a significant issue confronting the commercial silica industry. Concerns over silicosis and other potential adverse health effects, as well as concerns regarding potential liability from the use of silica, may have the effect of discouraging our customers’ use of our silica products. The actual or perceived health risks of mining, processing and handling silica could materially and adversely affect silica producers, including us, through reduced use of silica products, the threat of product liability or employee lawsuits, increased scrutiny by federal, state and local regulatory authorities of us and our customers or reduced financing sources available to the commercial silica industry.

Since at least 1975, we and/or our predecessors have been named as a defendant, usually among many defendants, in numerous products liability lawsuits brought by or on behalf of current or former employees of our customers alleging damages caused by silica exposure. We were the subject of 88 active silica exposure claims and 3,146 inactive claims as of February 26, 2014. Almost all of the claims pending against us arise out of the alleged use of our silica products in foundries or as an abrasive blast media, involve various other defendants and have been filed in the states of Texas, Louisiana and Mississippi, although some cases have been brought in many other jurisdictions over the years.

Prior to the fourth quarter of 2012, we had insurance policies for both our predecessors that covered certain claims for alleged silica exposure for periods prior to certain dates in 1985 and 1986 (with respect to various insurance). As a result of a settlement with a former owner and its insurers in the fourth quarter of 2012, some of these policies are no longer available to us and we will not seek reimbursement for any defense costs or claim payments from these policies. Other insurance policies, however, continue to remain available to us and will continue to make such payments on our behalf. The silica-related litigation brought against us to date and associated litigation costs, settlements and verdicts have not resulted in a material liability to us to date. However, we continue to have silica exposure claims filed against us, including claims that allege silica exposure for periods not covered by insurance, and the costs, outcome and impact to us of any pending or future claims is

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not certain. Any such pending or future claims or inadequacies of our insurance coverage could have a material adverse effect on our business, reputation, financial condition, results of operations, cash flows and prospects. For further information, see “Business—Legal Proceedings.”

We and our customers are subject to other extensive regulations, including licensing, plant and wildlife protection and reclamation regulation, that impose, and will continue to impose, significant costs and liabilities. In addition, future regulations, or more stringent enforcement of existing regulations, could increase those costs and liabilities, which could adversely affect our results of operations.

In addition to the regulatory matters described above, we and our customers are subject to extensive governmental regulation on matters such as permitting and licensing requirements, plant and wildlife protection, wetlands protection, reclamation and restoration of mining properties after mining is completed, the discharge of materials into the environment and the effects that mining and hydraulic fracturing have on groundwater quality and availability. Our future success depends, among other things, on the quantity of our commercial silica and other mineral deposits and our ability to extract these deposits profitably, and our customers being able to operate their businesses as they currently do.

In order to obtain permits and renewals of permits in the future, we may be required to prepare and present data to governmental authorities pertaining to the impact that any proposed exploration or production activities may have on the environment. Certain approval procedures may require preparation of archaeological surveys, endangered species studies and other studies to assess the environmental impact of new sites or the expansion of existing sites. Compliance with these regulatory requirements is expensive and significantly lengthens the time needed to develop a site. Finally, obtaining or renewing required permits is sometimes delayed or prevented due to community opposition and other factors beyond our control. The denial of a permit essential to our operations or the imposition of conditions with which it is not practicable or feasible to comply could impair or prevent our ability to develop or expand a site. Significant opposition to a permit by neighboring property owners, members of the public or other third parties or delay in the environmental review and permitting process also could impair or delay our ability to develop or expand a site. New legal requirements, including those related to the protection of the environment, could be adopted that could materially adversely affect our mining operations (including our ability to extract mineral deposits), our cost structure or our customers’ ability to use our commercial silica products. Such current or future regulations could have a material adverse effect on our business and we may not be able to obtain or renew permits in the future.

Our inability to acquire, maintain or renew financial assurances related to the reclamation and restoration of mining property could have a material adverse effect on our business, financial condition and results of operations.

We are generally obligated to restore property in accordance with regulatory standards and our approved reclamation plan after it has been mined. We are required under federal, state and local laws to maintain financial assurances, such as surety bonds, to secure such obligations. The inability to acquire, maintain or renew such assurances, as required by federal, state and local laws, could subject us to fines and penalties as well as the revocation of our operating permits. Such inability could result from a variety of factors, including:

Our inability to acquire, maintain or renew necessary financial assurances related to the reclamation and restoration of mining property could have a material adverse effect on our business, financial condition and results of operations.

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Mine closures entail substantial costs, and if we close one or more of our mines sooner than anticipated, our results of operations may be adversely affected.

We base our assumptions regarding the life of our mines on detailed studies that we perform from time to time, but our studies and assumptions do not always prove to be accurate. If we close any of our mines sooner than expected, sales will decline unless we are able to increase production at any of our other mines, which may not be possible. The closure of an open pit mine also involves significant fixed closure costs, including accelerated employment legacy costs, severance-related obligations, reclamation and other environmental costs and the costs of terminating long-term obligations, including energy contracts and equipment leases. We accrue for the costs of reclaiming open pits, stockpiles, tailings ponds, roads and other mining support areas over the estimated mining life of our property. If we were to reduce the estimated life of any of our mines, the fixed mine closure costs would be applied to a shorter period of production, which would increase production costs per ton produced and could materially and adversely affect our results of operations and financial condition.

Applicable statutes and regulations require that mining property be reclaimed following a mine closure in accordance with specified standards and an approved reclamation plan. The plan addresses matters such as removal of facilities and equipment, regrading, prevention of erosion and other forms of water pollution, re-vegetation and post-mining land use. We may be required to post a surety bond or other form of financial assurance equal to the cost of reclamation as set forth in the approved reclamation plan. The establishment of the final mine closure reclamation liability is based on permit requirements and requires various estimates and assumptions, principally associated with reclamation costs and production levels. If our accruals for expected reclamation and other costs associated with mine closures for which we will be responsible were later determined to be insufficient, our business, results of operations and financial condition would be adversely affected.

Risks Related to the Ownership of Our Common Stock

Our stock price could be volatile, and you may not be able to resell shares of your common stock at or above the price you paid.

The stock market has and continues to experience extreme price and volume fluctuations that have often been unrelated or disproportionate to the operating performance of the underlying businesses. Given our limited history as a public company, these fluctuations may be even more pronounced in the trading market for our stock. In addition, many industries have experienced a period of significant disruption characterized by the bankruptcy, failure, collapse or sale of various companies, which led to increased volatility in securities prices and a significant level of intervention from the U.S. and other governments in securities markets. These broad market and industry factors may seriously harm the market price of our common stock, regardless of our actual operating performance.

In addition to the risks described in this section, the market price of our common stock may fluctuate significantly in response to a number of factors, most of which we cannot control, including:

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Numerous factors affect our business and cause variations in our operating results and affect our net sales, including overall economic trends, our ability to identify and respond effectively to customer preferences, actions by competitors, pricing, the level of customer service that we provide, changes in product mix or sales channels, our ability to source and distribute products effectively and weather conditions.

Volatility in the market price of our common stock may prevent investors from being able to sell their common stock at or above the price at which you purchased the stock. As a result, you may suffer a loss on your investment.

Securities class action litigation has often been instituted against companies following periods of volatility in the overall market and in the market price of a company’s securities. This litigation, if instituted against us, could result in substantial costs, reduce our profits, divert our management’s attention and resources and harm our business.

Future sales of our common stock, or the perception in the public markets that these sales may occur, may depress our stock price.

Sales of substantial amounts of our common stock in the public market or the perception that these sales could occur, could adversely affect the price of our common stock and could impair our ability to raise capital through the sale of additional shares. As of February 21, 2014, we have 53,551,879 shares of common stock outstanding. These shares of common stock are freely tradable without restriction under the Securities Act, except for any shares of our common stock that may be held or acquired by our directors, executive officers and other affiliates, as that term is defined in the Securities Act, which will be restricted or control shares under the Securities Act. Restricted or control shares may not be sold in the public market unless the sale is registered under the Securities Act or an exemption from registration is available. If a large number of shares are sold on the open market, the price of our common stock could decline.

In the future, we may also issue securities if we need to raise capital in connection with a capital raise or acquisition. The amount of shares of our common stock issued in connection with a capital raise or acquisition could constitute a material portion of our then outstanding shares of common stock.

Anti-takeover provisions in our charter documents and Delaware law might discourage or delay acquisition attempts for us that you might consider favorable.

Our certificate of incorporation and bylaws contain provisions that may make the acquisition of our company more difficult without the approval of our Board. These provisions:

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Our certificate of incorporation also contains a provision that provides us with protections similar to Section 203 of the Delaware General Corporation Law (the “DGCL”), and will prevent us from engaging in a business combination with a person who acquires at least 15% of our common stock for a period of three years from the date such person acquired such common stock, unless Board or stockholder approval is obtained prior to the acquisition. These anti-takeover provisions and other provisions under Delaware law could discourage, delay or prevent a transaction involving a change in control of our company, even if doing so would benefit our stockholders. These provisions could also discourage proxy contests and make it more difficult for you and other stockholders to elect directors of your choosing and to cause us to take other corporate actions you desire.

If securities or industry analysts do not publish research or publish inaccurate or unfavorable research about our business, our stock price and trading volume could decline.

The trading market for our common stock depends in part on the research and reports that securities or industry analysts publish about us or our business. If one or more of the analysts who covers us downgrades our stock or publishes inaccurate or unfavorable research about our business, our stock price would likely decline. If one or more of these analysts ceases coverage of us or fails to publish reports on us regularly, demand for our stock could decrease, which could cause our stock price and trading volume to decline.

Holders of our common stock may not receive dividends on our common stock.

Holders of our common stock are entitled to receive only such dividends as our Board may declare out of funds legally available for such payments. We are incorporated in Delaware and are governed by the DGCL. The DGCL allows a corporation to pay dividends only out of a surplus, as determined under Delaware law or, if there is no surplus, out of net profits for the fiscal year in which the dividend was declared and for the preceding fiscal year. Under the DGCL, however, we cannot pay dividends out of net profits if, after we pay the dividend, our capital would be less than the capital represented by the outstanding stock of all classes having a preference upon the distribution of assets. While management and our Board remain committed to evaluating additional ways of creating shareholder value, any determination to pay dividends and other distributions in cash, stock or property by us in the future will be at the discretion of our Board and will be dependent on then-existing conditions, including business conditions, our financial condition, results of operations, liquidity, capital requirements, contractual restrictions including restrictive covenants contained in debt agreements and other factors. While we have recently declared and paid a quarterly cash dividend on our common stock as described under Part II, Item 5 of this Annual Report on Form 10-K, we are not required to declare future cash dividends on our common stock.

We incur increased costs as a result of being a public company.

As a public company, we incur significant legal, accounting, insurance and other expenses, including costs associated with public company reporting requirements. We also have incurred and will incur costs associated with complying with the requirements of the Sarbanes-Oxley Act of 2002, the Dodd-Frank Act of 2010, and related rules implemented by the SEC and the NYSE. In particular, we have been required to do the following:

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The expenses incurred by public companies generally for reporting and corporate governance purposes have been increasing. We expect these rules and regulations to increase our legal and financial compliance costs and to make some activities more time-consuming and costly, although we are currently unable to estimate these costs with any degree of certainty.

These laws and regulations could also make it more difficult or costly for us to obtain certain types of insurance, including director and officer liability insurance, and we may be forced to accept reduced policy limits and coverage or incur substantially higher costs to obtain the same or similar coverage. These laws and regulations could also make it more difficult for us to attract and retain qualified persons to serve on our Board, our Board committees or as our executive officers. Furthermore, if we are unable to satisfy our obligations as a public company, we could be subject to delisting of our common stock, fines, sanctions and other regulatory action and potentially civil litigation.

None.

Our corporate headquarters is located in Frederick, Maryland. In addition, we maintain corporate support centers and sales offices in Chicago, Illinois, Houston, Texas and Shanghai, China.

As of February 26, 2014, we operate 15 production facilities located primarily in the eastern half of the United States, with operations in Alabama, Illinois (2), Louisiana, Michigan, Missouri, New Jersey, Oklahoma, Pennsylvania, South Carolina, Tennessee, Texas, Virginia, West Virginia and Wisconsin. We also own one undeveloped site in Arkansas and are developing a third production facility in Illinois, which we expect to take ownership of by the end of the second quarter of 2014. We also own a transload site and lease additional transload sites.

Additionally, we operate corporate laboratories located on-site at our Berkeley Springs, West Virginia and Houston, Texas facilities that provide critical technical expertise, analytical testing resources and application development to promote product value and cost savings. The following map shows the locations of our U.S. facilities.

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We generally own our principal production properties, although some land is leased. Substantially all of our owned assets are pledged as security under our senior secured credit facility; for additional information regarding our indebtedness, see Item 7, “Management’s Discussion and Analysis of Financial Condition and Results of Operations–Liquidity and Capital Resources.” Corporate offices, including sales locations are leased. In general, we consider our facilities, taken as a whole, to be suitable and adequate for our current operations. However, we will continue to invest significant resources to increase production capacity through strategic initiatives, including Greenfield projects such as our new facility in Sparta, Wisconsin and Brownfield expansion projects such as the potential expansion of capacity at our existing facilities, including our new resin-coating facility.

Our Facilities

The following is a detailed description of our 15 production facilities and our currently undeveloped site in Batesville, Arkansas.

Ottawa, Illinois

Our surface mines in Ottawa use natural gas and electricity to produce whole grain and ground silica through a variety of mining methods, including hard rock mining, mechanical mining and hydraulic mining. The reserves are part of the St. Peter Sandstone deposit that stretches north-south from Minnesota to Missouri and east-west from Illinois to Nebraska and South Dakota. The facility is located approximately 80 miles southwest of Chicago and is accessible by major highways including U.S. Interstate 80.

We acquired the Ottawa facility in 1987 by merger with the Ottawa Silica Company, which had historically used the property to produce whole grain and ground silica for customers in industrial and specialty products end markets. Since acquiring the facility we have renovated and upgraded its production capabilities to enable it to produce multiple products through various processing methods, including washing, hydraulic sizing, grinding,

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screening and blending. These production techniques allow the Ottawa facility to meet a wide variety of focused specifications on product composition from customers. As such, the Ottawa facility services multiple end markets, such as glass, building products, foundry, fillers and extenders, chemicals and oil and gas proppants. In November 2009, we expanded the frac sand capacity of this facility by 500,000 tons. During the fourth quarter of 2011, we completed a follow-on expansion project that added an additional 900,000 tons of frac sand capacity. Once the product is appropriately processed, it is shipped either in bulk or packaged form by rail by either the CSX Corporation or the BNSF Railway Company (via the Illinois Railway short line), truck or barge through terminals located on the plant site and at a leased site approximately three miles from the plant. In 2013, we purchased a related existing silica sand processing facility from Quality Sand Products, LLC (QSP) in Peru, Illinois.

Mill Creek, Oklahoma

Our surface mines in Mill Creek use natural gas and electricity to produce whole grain, ground and fine ground silica through a variety of mining methods, including hard rock and hydraulic mining. The reserves are part of the Oil Creek Formation in south central Oklahoma. The facility is located approximately 100 miles southeast of Oklahoma City and is accessible by major highways including U.S. Interstate 35.

We acquired the Mill Creek facility in 1987 by merger with the Pennsylvania Glass Sand Corporation, which had historically used the property to produce whole grain silica for customers in industrial and specialty products end markets. Since acquiring the facility we have renovated and upgraded its production capabilities to enable it to produce multiple products through various processing methods, including hydraulic sizing, fluid bed drying, grinding and scalping. These production techniques allow the Mill Creek facility to meet a wide variety of focused specifications on product composition from customers. As such, the Mill Creek facility services multiple end markets, such as glass, foundry, fillers and extenders, building products and oil and gas proppants. Once the product is appropriately processed, it is packaged in bulk and shipped either by rail by BNSF Railway Company or by truck.

Pacific, Missouri

Our surface mines at the Pacific facility use natural gas and electricity to produce whole grain, ground and fine ground silica through a variety of mining methods, including hard rock and hydraulic mining. The reserves are part of the St. Peter Sandstone deposit that stretches north-south from Minnesota to Missouri and east-west from Illinois to Nebraska and South Dakota. The facility is located approximately 50 miles southwest of St. Louis and is accessible by major highways including U.S. Interstate 44.

We acquired the Pacific facility in 1987 by merger with the Pennsylvania Glass Sand Corporation, which had historically used the property to produce whole grain silica for customers in industrial and specialty products end markets. Since acquiring the facility we have renovated and upgraded its production capabilities to enable it to produce multiple products through various processing methods, including hydraulic sizing, fluid bed drying, grinding, dry screening, classifying and microsizing. In August 2010, we expanded this facility’s processing capabilities to include the processing of frac sand. These production techniques allow the Pacific facility to meet a wide variety of focused specifications on product composition from customers. As such, the Pacific facility services multiple end markets, such as glass, foundry, fillers and extenders and oil and gas proppants. Once the product is appropriately processed, it is packaged in bulk and shipped either by rail directly by Union Pacific Corporation and through open switching on the same line by BNSF Railway Company or by truck.

Berkeley Springs, West Virginia

Our surface mines at the Berkeley Springs facility use fuel oil and electricity to produce whole grain, ground and fine ground silica and Florisil through hard rock mining. The reserves are part of the Oriskany Sandstone Formation along the Warm Springs Ridge in eastern West Virginia. The facility is located approximately 100 miles northwest of Baltimore and is accessible by major highways including U.S. Interstate 70.

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We acquired the Berkeley Springs facility in 1987 by merger with the Pennsylvania Glass Sand Corporation, which had historically used the property to produce whole grain silica for customers in industrial and specialty products end markets. Since acquiring the facility we have renovated and upgraded its production capabilities to enable it to produce multiple products through various processing methods, including primary, secondary and tertiary crushing, grinding, flotation, de-watering, fluid bed drying, mechanical screening and rotary drying processing. These production techniques allow the Berkeley Springs facility to meet a wide variety of focused specifications from customers producing specialty epoxies, resins and polymers, geothermal energy equipment and fiberglass. As such, the Berkeley Springs facility services multiple end markets, such as glass, building products, foundry, chemicals and fillers and extenders. Once the product is appropriately processed, it is packaged in bulk and shipped by rail by the CSX Corporation or truck.

Rockwood, Michigan

Our surface mines at the Rockwood facility use natural gas and electricity to produce whole grain silica. The reserves are part of the Sylvania Formation and are notable for their low iron content, making them particularly valuable to customers producing specialty glass for architectural or alternative energy applications. The facility is located approximately 30 miles southwest of Detroit and is accessible by major highways including U.S. Interstate 75.

We acquired the Rockwood facility in 1987 by merger with the Ottawa Silica Company, which had historically used the property to produce whole grain and ground silica for customers in industrial and specialty products end markets. Since acquiring the facility we have renovated and upgraded its production capabilities to enable it to produce multiple products through various processing methods, including fluid bed drying, dry screening and classifying. These production techniques allow the Rockwood facility to meet a wide variety of focused specifications on product composition from customers. As such, the Rockwood facility services multiple end markets, such as glass, building products, oil and gas proppants and chemicals. During the fourth quarter of 2011, we completed the addition of 250,000 tons of annual frac sand capacity at the Rockwood facility by installing an entirely new processing circuit. Once the product is appropriately processed, it is packaged in bulk and shipped by rail via the Canadian National Railway or truck.

Mapleton Depot, Pennsylvania

Our surface mines in Mapleton Depot use natural gas, fuel oil and electricity to produce whole grain silica through hard rock mining. The reserves are part of the Oriskany Sandstone Formation deposit in central Pennsylvania. The facility is located approximately 40 miles northwest of Harrisburg and is accessible by major highways including U.S. Interstates 99, 80 and 76.

We acquired the Mapleton Depot facility in 1987 by merger with the Pennsylvania Glass Sand Corporation, which had historically used the property to produce whole grain silica for customers in industrial and specialty products end markets. Since acquiring the facility, we have renovated and upgraded its production capabilities to enable it to produce multiple products through various processing methods, including hydraulic sizing, fluid bed drying, scalping and a low iron circuit. These production techniques allow the Mapleton Depot facility to meet a wide variety of focused specifications on product composition from customers. As such, the Mapleton Depot facility services multiple end markets, such as glass, specialty glass, building products and recreation. Once the product is appropriately processed, it is packaged in bulk and shipped either by rail by Norfolk Southern Corporation or by truck.

Kosse, Texas

Our surface mines in Kosse use natural gas and electricity to produce whole grain silica and kaolin clay through scraping mining. The reserves are part of the Simsboro member of the Rockdale Formation in central Texas. The facility is located approximately 90 miles south of Dallas and is accessible by major highways including U.S. Interstates 45 and 35.

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We acquired the Kosse facility in 1987 by merger with the Ottawa Silica Company, which had historically used the property to produce whole grain silica and kaolin clay for customers in industrial and specialty products end markets. Since acquiring the facility, we have renovated and upgraded its production capabilities to enable it to produce multiple products through various processing methods, including washing, hydraulic sizing, fluid bed drying, dry screening, centrifuging and spray drying. These production techniques allow the Kosse facility to meet a wide variety of focused specifications on product composition from customers. As such, the Kosse facility services multiple end markets, such as glass, building products, fillers and extenders and recreation. Once the product is appropriately processed, it is packaged in bag or bulk and shipped either by rail by Union Pacific Railroad or by truck.

Mauricetown, New Jersey

Our surface mines near the Mauricetown facility use natural gas, fuel oil and electricity, to produce whole grain silica through dredge mining. The reserves are mined from the Maurice River and are similar to those found in the Cohansey, Bridgeton and Cape May deposits. The facility is located approximately 50 miles south of Philadelphia and is accessible by major highways including U.S. Interstate 295 and state Highway 55.

We acquired the Mauricetown facility in 1999 from Unimin Corporation, which had historically used the property to produce whole grain silica for customers in industrial and specialty products end markets. Since acquiring the facility, we have renovated and upgraded its production capabilities, including the construction of a new wet processing plant, to enable it to produce multiple products through various processing methods, including washing, hydraulic sizing, fluid bed drying, rotary drying and scalping. These production techniques allow the Mauricetown facility to meet a wide variety of focused specifications on product composition from customers. As such, the Mauricetown facility services multiple end markets, such as foundry, filtration, building products and recreation. Once the product is appropriately processed, it is packaged in bags or bulk and shipped either by rail by Winchester & Western Railroad or by truck.

Columbia, South Carolina

Our surface mines in Columbia use natural gas, fuel oil and electricity to produce whole grain, ground and fine ground silica through dune mining. The reserves are part of the Tuscaloosa Formation near central South Carolina. The facility is located approximately 10 miles west of Columbia and is accessible by major highways including U.S. Interstates 26 and 20.

We acquired the Columbia facility in 1987 by merger with the Pennsylvania Glass Sand Corporation, which had historically used the property to produce whole grain silica for customers in industrial and specialty products end markets. Since acquiring the facility, we have renovated and upgraded its production capabilities to enable it to produce multiple products through various processing methods, including hydraulic sizing, fluid bed drying, scalping and grinding. These production techniques allow the Columbia facility to meet a wide variety of focused specifications on product composition from customers. As such, the Columbia facility services multiple end markets, such as glass, building products, fillers and extenders, filtration and oil and gas proppants. Once the product is appropriately processed, it is bagged or shipped in bulk either by rail by Norfolk Southern Corporation or by truck.

Montpelier, Virginia

Our surface mine in Montpelier uses fuel oil and electricity to produce aplite through hard rock mining. The reserves are part of igneous rock deposits that are unique to this location. The facility is located approximately 20 miles northwest of Richmond and is accessible by major highways including U.S. Interstates 64 and 95.

We acquired the Montpelier facility in 1993 from The Feldspar Company, which had historically used the property to produce aplite for customers in industrial and specialty products end markets. Since acquiring the facility, we have renovated and upgraded its production capabilities to enable it to produce multiple products

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through various processing methods, including hydraulic crushing and sizing, washing, fluid bed drying and grinding. These production techniques allow the Montpelier facility to meet a wide variety of focused specifications on product composition from customers. As such, the Montpelier facility services multiple end markets, such as glass, building products and recreation. Once the product is appropriately processed, it is packaged in bulk and shipped either by rail by Norfolk Southern Corporation or CSX Corporation or by truck.

Jackson, Tennessee

Our surface mines in Jackson use natural gas and electricity to produce whole grain, ground and fine ground silica through dredge mining. The reserves are part of the Clairborne Formation, which is part of the Gulf Coastal Plain-Upper Mississippi Embayment. The facility is located approximately 75 miles northeast of Memphis and is accessible by major highways including U.S. Interstate 40.

We acquired the Jackson facility in 1997 from Nicks Silica Company, which had historically used the property to produce whole grain and ground silica for customers in industrial and specialty products end markets. Since acquiring the facility, we have renovated and upgraded its production capabilities, turning it into one of our premier grinding facilities and enabling it to produce multiple products through various processing methods, including rotary drying, screening and grinding.

These production techniques allow the Jackson facility to meet a wide variety of focused specifications on product composition from customers. As such, the Jackson facility services multiple end markets, such as fiberglass, building products, ceramics, fillers and extenders and recreation. Once the product is appropriately processed, it is shipped in bulk by truck.

Dubberly, Louisiana

Our surface mines in Dubberly use natural gas and electricity to produce whole grain silica through dredge mining. The reserves are part of the Sparta deposit. The facility is located approximately 30 miles east of Shreveport and is accessible by major highways including U.S. Interstate 20 and state Highway 63.

We acquired the Dubberly facility in 1987 by merger with the Ottawa Silica Company, which had historically used the property to produce whole grain silica for customers in industrial and specialty products end markets. Since acquiring the facility, we have renovated and upgraded its production capabilities to enable it to produce multiple products through various processing methods, including screening, washing, rotary drying and conditioning to remove heavy and iron bearing minerals. These production techniques allow the Dubberly facility to meet a wide variety of focused specifications on product composition from customers. As such, the Dubberly facility services multiple end markets, such as glass, foundry and building products. Once the product is appropriately processed, it is bagged or shipped in bulk by truck.

Hurtsboro, Alabama

Our surface mines in Hurtsboro use propane and electricity, to produce whole grain silica. Sand feed for processing is trucked in from surrounding mine locations. The reserves are mined from the Cusseta member of the lower Ripley deposit Formation. The facility is located approximately 75 miles east of Montgomery and is accessible by major highways including U.S. Interstate 85 and state Highway 431.

We acquired the Hurtsboro facility in 1988 from Warrior Sand & Gravel Company, which had historically used the property to produce whole grain silica for customers in industrial and specialty products end markets. Since acquiring the facility, we have renovated and upgraded its production capabilities to enable it to produce multiple products through various processing methods, including trucking in sand from surrounding locations, hydraulic sizing, screening and fluid bed drying. These production techniques allow the Hurtsboro facility to meet a wide variety of focused specifications on product composition from customers. As such, the Hurtsboro

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facility services multiple end markets, such as foundry, building products and recreation. Once the product is appropriately processed, it is shipped in bulk by truck.

Rochelle, Illinois

The Rochelle property was purchased in 2011, and we spent 2011 and 2012 planning and constructing a resin coating facility on the property.

The Rochelle facility has two process lines, each with the capacity to coat 100,000 tons of substrate. The facility has the flexibility to coat numerous substrates using novolac or resole resin technology. Sand can be received and shipped both by truck and rail to help meet customer requirements. One of the competitive strengths of the facility is the capability to ship by the BNSF and Canadian Pacific railroads both being Class I railroads serving many key locations throughout United States.

By the end of 2012, the Rochelle facility produced and qualified resin coated sand that meets standards for the oil and gas market. The facility has the potential to add process lines and service other markets as customer demands evolve and grow.

In the first quarter of 2014, we completed modifications to the Rochelle facility which enable it to function, in part, as a transload as well as being unit train capable. These changes now enable the plant to ship raw sand to multiple destinations across the country.

Sparta, Wisconsin

The Sparta property was acquired on December 30, 2011, and site development began in April 2012. Sand dredging and the wet process plant operations were launched in September 2012, resulting in an initial production of over 150,000 tons of dryer feed stockpile by December 1, 2012. By mid-December 2012, the first of two planned fluid-bed, natural gas dryers and the dry screening circuit was commissioned. These activities culminated in the loading of our first railcar of finished product on December 30, 2012. Phase 2 construction activities began in January 2013, and the facility became fully operational in the second quarter of 2013.

The Sparta deposit contains over 36 million tons of proven ore reserves. The geology is comprised of high purity sands of the Wonewoc Formation. The Wonewoc Sandstone Formation is known for its round, coarse grains and superior crush strength properties, which makes it an ideal substrate for oil and gas proppants. The Sparta property is located 25 miles northeast of La Crosse, WI; approximately 120 miles northwest of Madison, WI; and is readily accessible by both Interstate 90 and the Canadian Pacific railroad. In accordance with the conditional use permit, finished products will only be shipped in bulk by rail.

Batesville, Arkansas

Whitebuck is a sandstone deposit with over 34 million tons of probable reserves near the town of Batesville, Arkansas. We acquired the reserves in 2010 from White Buck, LLC. There is no facility on the property and it is not currently permitted. We received a mine permit in March 2012. The deposit has high purity sandstone and can provide a long-term supplement to the reserves at our Mill Creek operations. The reserves are part of the St. Peter Sandstone deposit, which is part of the same formation being mined at our Ottawa and Pacific operations. The property is located approximately 85 miles northeast of Little Rock and is accessible by highways including state Highways 67 and 167.

Our Reserves

We believe we have a broad and high-quality mineral reserves base due to our strategically located mines and facilities. “Reserves” are defined by SEC Industry Guide 7 as that part of a mineral deposit which could be

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economically and legally extracted or produced at the time of the reserve determination. Industry Guide 7 divides reserves between “proven (measured) reserves” and “probable (indicated) reserves” which are defined as follows:

We categorize our reserves as proven or probable in accordance with these SEC definitions. We estimate that we had a total of approximately 297 million tons of proven and probable recoverable mineral reserves as of December 31, 2013. The quantity and nature of the mineral reserves at each of our properties are estimated by our internal geologists and mining engineers. Our internal geologists and engineers update our reserve estimates annually, making necessary adjustments for operations at each location during the year and additions or reductions due to property acquisitions and dispositions, quality adjustments and mine plan updates. Before acquiring new reserves, we perform surveying, drill core analysis and other tests to confirm the quantity and quality of the acquired reserves. In some instances, we acquire the mineral rights to reserves without actually taking ownership of the properties.

Description of Deposits

The following is a description of the nature of our silica and aplite deposits for each of our reserve locations:

Ottawa, Illinois

The deposit has a minimum silica (SiO₂) content of 99%. The controlling attributes are iron (Fe₂O₃ ) content and grain size distribution. Iron is concentrated near the surface, where orange iron staining is evident and also increases where the bottom contact becomes concentrated in iron pyrite. Maximum average full face iron content is 0.045%. The deposit tends to run a coarser grain size distribution in top half of deposit.

Mill Creek, Oklahoma

The deposit has a minimum silica (SiO₂) content of 99%. The controlling attributes are iron (Fe₂O ₃) content, calcium (CaO) and grain size distribution. Multiple faces are exposed to average out variability in grain size and iron. The sand/overburden contact is occasionally concentrated in calcium and any sand with greater than 0.30% CaO is removed during the overburden removal process. Sand with iron greater than 0.025% is not mined.

Pacific, Missouri

The deposit has a minimum silica (SiO₂) content of 99%. The controlling attributes are iron (Fe₂O₃) and calcium (CaO). Calcium can be concentrated at upper sand contact with overlying carbonate cap rock. This enriched calcium zone is known from drill sample results and is stripped during the overburden removal process. Average full mining face washed sand samples are less than 0.03% iron and 0.05% calcium.

Berkeley Springs, West Virginia

The deposit has a minimum silica (SiO₂) content of 99%. The controlling attribute is iron (Fe₂O₃ ). Ore that is higher than 0.06% iron is not mined. Ore less than 0.06% iron is mined and blended for feed to plant.

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Mapleton Depot, Pennsylvania

The deposit has a minimum silica (SiO₂) content of 99%. The controlling attribute is iron (Fe₂O₃ ). Ore that is higher than 0.06% iron is not mined. Ore less than 0.06% iron is mined and blended for feed to plant.

Kosse, Texas

The deposit has a minimum silica (SiO₂) content of 99%. The controlling attributes are iron content (Fe₂O₃) for kaolin and sand and size distribution for sand. Up to three different pits are mined at any one time to assure consistency of ore and to smooth out variability of attributes. Maximum sand irons are 0.045% and clay irons are 1.05%.

Mauricetown, New Jersey

The deposit has a minimum silica (SiO₂) content of 99%. There is no critical attribute in the mining of this deposit other than that occasional zones high in clay are avoided in the course of dredge mining.

Columbia, South Carolina

The deposit has a minimum silica (SiO₂) content of 99%. The controlling attributes are iron content (Fe₂O₃) and percentage of clay/slimes. Clay content increases at depth and generally the pit bottom follows a marker bed at 250-foot elevation where clay content is in excess of 11%. Sand having iron values greater than 0.03% are avoided and not mined.

Montpelier, Virginia

Montpelier produces alumina sands (aplite) from an anorthosite, which intruded into the Sabot Gneiss, a Precambrian amphibolite. The ore body is characterized as a dome-like structure and comprised of two general phases: a coarse-grained, non-foliated phase and a granulated, medium-grained, foliated phase.

The deposit is variable in its geologic nature and contains masses of host rock (consisting of granite gneiss, biotite gneiss and amphibolites) along with occasional dikes. The deposit is highly weathered and soft near the surface. Hardness and strength increase with depth.

Aplite is used as a flux agent in glass making and is sold to the same glass end markets and used in the same processes and in a similar manner as our silica product.

The aplite ore (andesine feldspar) deposit is intermixed with an assemblage of other minerals that must be separated out to make an acceptable product. The controlling attributes are titanium (TiO₂), aluminum (AI₂O₃ ), iron (Fe₂O₃) and phosphorous (P₂O₅). Ore is blended from multiple faces to produce a product generally at 21% AI₂O₃, 0.25% Fe₂O₃ , 0.11% TiO₂, and 0.55% P₂O₅.

Rockwood, Michigan

The deposit has a minimum silica (SiO₂) content of 99%. The controlling attribute is iron content (Fe₂O₃). Mineable sand must have less than 0.01% Fe2O3.

Jackson, Tennessee

The deposit has a minimum silica (SiO₂) content of 99%. The controlling attribute of iron (Fe₂O₃ ) content is managed through keeping clay overburden from intermixing with the sand and maintaining adequate washing of sand in the wet processing of the sand.

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Dubberly, Louisiana

The deposit has a minimum silica (SiO₂) content of 99%. The controlling attributes are iron (Fe₂O₃ ) content and grain size distribution. Mining full-face average for iron is 0.045%. The grain size distribution averages greater than 25% plus 50 mesh. Fine and coarse areas are blended to meet the grain size average.

Hurtsboro, Alabama

The deposit has a minimum silica (SiO₂) content of 99%. The controlling attribute is grain size distribution. Sand reserves are located on the crests of rolling hills and mining occurs from multiple pits and faces within pits to assure optimum grain size distribution is available to meet the market product mix.

Sparta, Wisconsin

The deposit has a minimum silica (SiO₂) content of 99%. The controlling attributes are sand grain crush strength and size distribution. A thin layer of silt overlies 50 to 100 foot thick sand deposit. The deposit is unconsolidated, well sorted and falls predominantly within the 20/70 grain size distribution.

Batesville, Arkansas

The deposit has a minimum silica (SiO₂) content of 99%. The controlling attribute is iron (Fe₂O₃) content. The deposit has two horizons; a low iron horizon where sand has less than 0.009% Fe2O3 and a regular iron horizon where sand has greater than 0.009% Fe₂O₃ .

Mineral Rights

The mineral rights and access to mineral reserves for the majority of our operations are secured through land that is owned in fee. There are no underlying agreements and/or royalties associated with these lands. The operations in this category include: Berkeley Springs, Dubberly, Jackson, Kosse, Mauricetown, Montpelier, Ottawa, Pacific, Batesville, Rockwood and Sparta.

The mineral rights and access to mineral reserves at our Mill Creek operation are a combination of land owned in fee that includes a non-participating royalty payment of $0.11 per saleable ton that was contractually negotiated with and paid to the original sellers of the property that covers 95% of the reserves and a lease agreement on one property that involves an annual minimum payment of $50,000 and a production royalty payment of $0.55 per saleable ton on the remaining 5% of reserves.

The Columbia operation mineral reserves and rights are secured under a long-term mineral lease. The lease expires in 2033 and includes an annual minimum payment of $175,000 and a production royalty of 5.5% of the gross revenue.

The Hurtsboro operation mineral reserves and rights are secured under two mineral leases. The majority of the reserves are under a long-term lease that expires in 2019 and includes an annual minimum payment of $8,000 and a production royalty payment of 3% of weighted average selling price. The second mineral lease expires in 2015 and includes an annual minimum payment of $15,000 and a production royalty of 3.3% of the weighted average selling price, which will escalate to 3.35% on June 1, 2014. The mineral leases have been renewed in the past, and it is expected that if mining is still occurring on this property we will have no problem negotiating an extension of these leases.

The Mapleton Depot operation mineral reserves and rights are secured under two long-term mineral leases that expire in 2025 but may continue thereafter on a year-to-year basis if mining is still occurring. Annual minimums are $1,000, and production royalty payments are either 6.5% of free on board pit price or 0.255 cents per mined ton, whichever is higher.

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None of our operations are on government land and, accordingly, we do not have any mineral rights or associated mining claims.

Summary of Reserves

The following table provides information on our 14 production facilities that have reserves, and a currently undeveloped site in Batesville, Arkansas, as of December 31, 2013. Included is the location and area of the facility; the type, amount and ownership status of its reserves; and the primary end markets that it serves. Our facility in Rochelle, IL has no reserves.

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In addition to the matter described below, we are subject to various legal proceedings, claims, and governmental inspections, audits or investigations arising out of our business which cover matters such as general commercial, governmental regulations, antitrust and trade regulations, product liability, environmental, intellectual property, employment and other actions. Although the outcomes of these routine claims cannot be predicted with certainty, in the opinion of management, the ultimate resolution of these matters will not have a material adverse effect on our financial position or results of operations.

Prolonged inhalation of excessive levels of respirable crystalline silica dust can result in silicosis, a disease of the lungs. Breathing large amounts of respirable silica dust over time may injure a person’s lungs by causing scar tissue to form. Crystalline silica in the form of quartz is a basic component of soil, sand, granite and most other types of rock. Cutting, breaking, crushing, drilling, grinding and abrasive blasting of or with crystalline silica containing materials can produce fine silica dust, the inhalation of which may cause silicosis, lung cancer and possibly other diseases including immune system disorders such as scleroderma. Sources of exposure to respirable crystalline silica dust include sandblasting, foundry manufacturing, crushing and drilling of rock, masonry and concrete work, mining and tunneling, and cement and asphalt pavement manufacturing.

Since at least 1975, we and/or our predecessors have been named as a defendant, usually among many defendants, in numerous lawsuits brought by or on behalf of current or former employees of our customers alleging damages caused by silica exposure. Prior to 2001, the number of silicosis lawsuits filed annually against the commercial silica industry remained relatively stable and was generally below 100, but between 2001 and 2004 the number of silicosis lawsuits filed against the commercial silica industry substantially increased. This increase led to greater scrutiny of the nature of the claims filed, and in June 2005 the U.S. District Court for the Southern District of Texas issued an opinion in the former federal silica multi-district litigation remanding almost all of the 10,000 cases then pending in the multi-district litigation back to the state courts from which they originated for further review and medical qualification, leading to a number of silicosis case dismissals across the United States. In conjunction with this and other favorable court rulings establishing “sophisticated user” and “no duty to warn” defenses for silica producers, several states, including Texas, Ohio and Florida, have passed medical criteria legislation that requires proof of actual impairment before a lawsuit can be filed.

As a result of the above developments, the filing rate of new claims against us over the past few years has decreased to below pre-2001 levels, and we were named as a defendant in three, two and three new silicosis cases filed in 2011, 2012 and 2013, respectively. As of February 26, 2014, there were a total of 88 active silica-related products liability claims pending in which we were a defendant and 3,146 inactive claims. Almost all of the claims pending against us arise out of the alleged use of our silica products in foundries or as an abrasive blast media, and involve various other defendants. Prior to the fourth quarter of 2012, we had insurance policies for both our predecessors that cover certain claims for alleged silica exposure for periods prior to certain dates in 1985 and 1986 (with respect to various insurance). As a result of a settlement with a former owner and its insurers in the fourth quarter of 2012, some of these policies are no longer available to us and we will not seek reimbursement for any defense costs or claim payments from these policies. Other insurance policies, however, continue to remain available to us and will continue to make such payments on our behalf.

The silica-related litigation brought against us to date has not resulted in material liability to us. However, we continue to have silica-related products liability claims filed against us, including claims that allege silica exposure for periods for which we do not have insurance coverage. Any such pending or future claims or inadequacies of our insurance coverage could have a material adverse effect on our business, reputation or results

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of operations. For more information regarding silica-related litigation, see “Risk Factors—Risks Related to Our Business—Silica-related health issues and litigation could have a material adverse effect on our business, reputation or results of operations.”

At U.S. Silica, safety is a core value and we strive for excellence in the achievement of a workplace free of injuries and occupational illnesses. Our health and safety leadership team has developed comprehensive safety policies and standards, which include detailed standards and procedures for safe production, addressing topics such as employee training, risk management, workplace inspection, emergency response, accident investigation and program auditing. We place special emphasis on the importance of continuous improvement in occupational health, personal injury avoidance and prevention, emergency preparedness, and property damage elimination. In addition to strong leadership and involvement from all levels of the organization, these programs and procedures form the cornerstone of safety at U.S. Silica, ensuring that employees are provided a safe and healthy environment and are intended as a means to reduce workplace accidents, incidents and losses, comply with all mining-related regulations and provide support for both regulators and the industry to improve mine safety. While we want to have productive operations in full regulatory compliance, we know it is equally essential that we motivate and train our people to think, practice and feel a personal responsibility for health and safety on and off the job.

All of our production facilities are classified as mines and are subject to regulation by the MSHA under the Federal Mine Safety and Health Act of 1977 (the “Mine Act”). MSHA inspects our mines on a regular basis and issues various citations and orders when it believes a violation has occurred under the Mine Act. Following passage of The Mine Improvement and New Emergency Response Act of 2006, MSHA significantly increased the numbers of citations and orders charged against mining operations. The dollar penalties assessed for citations issued has also increased in recent years. Information concerning mine safety violations or other regulatory matters required by Section 1503(a) of the Dodd-Frank Wall Street Reform and Consumer Protection Act and Item 104 of Regulation S-K (17 CFR 229.104) is included in Exhibit 95.1 to this Annual Report filed on Form 10-K.

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PART II

Market Information

Shares of our common stock, traded under the symbol “SLCA,” have been publicly traded since February 1, 2012, when our common stock was listed and began trading on the NYSE. Accordingly, no market for our stock existed prior to February 1, 2012.

The following table sets forth for the indicated periods, the high and low sales prices, per share, for our common stock on the NYSE.

Holders of Record

On February 21, 2014, there were 53,551,879 shares of our common stock outstanding, which were held by approximately 16 stockholders of record. Because many of our shares of common stock are held by brokers and other institutions on behalf of stockholders, we are unable to estimate the total number of stockholders represented by these record holders. For additional information related to ownership of our stock by certain beneficial owners and management, refer to Item 12, “Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters.”

Dividend

We pay dividends on our common stock after the Board declares them. Management and the Board remain committed to evaluating additional ways of creating shareholder value. Any determination to pay dividends and other distributions in cash, stock, or property by U.S. Silica in the future will be at the discretion of the Board and will be dependent on then-existing conditions, including our business conditions, our financial condition, results of operations, liquidity, capital requirements, contractual restrictions including restrictive covenants contained in debt agreements and other factors.

We declared a special dividend of $0.50 per share in December 2012. In 2013, we declared quarterly dividends as follows:

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Purchase of Equity Securities by the Issuer and Affiliated Purchasers

From time to time, we repurchase our common stock in the open market pursuant to programs approved by the Board. We may repurchase our common stock for a variety of reasons, such as to offset dilution related to equity-based incentives and to optimize our capital structure.

On June 11, 2012, the Board authorized us to repurchase up to $25.0 million of our common stock. The authorization was initially for a period of 18 months, concluding on December 11, 2013, but on November 4, 2013, the Board extended the repurchase program through December 11, 2014. We are authorized to repurchase, from time to time, shares of our outstanding common stock on the open market or in privately negotiated transactions. Stock repurchases will be funded using our available liquidity. The timing and amount of stock repurchases will depend on a variety of factors, including the market conditions as well as corporate and regulatory considerations. The share repurchase program may be suspended, modified or discontinued at any time and we have no obligation to repurchase any additional amount of our common stock under the program. We intend to make all repurchases in compliance with applicable regulatory guidelines and to administer the plan in accordance with applicable laws, including Rule 10b-18 of the Securities Exchange Act of 1934, as amended. As part of the program, as of December 31, 2013, we have repurchased 100,000 shares of our common stock at an average price of $10.72 and are authorized to repurchase up to an additional $23.9 million of our common stock. As of December 31, 2013, all of the 100,000 shares repurchased to date have been re-issued to satisfy employee option exercises.

We consider several factors in determining when to make share repurchases including, among other things, our cash needs, the availability of funding, our future business plans and the market price of our stock. We expect that cash provided by future operating activities, as well as available liquidity, will be the sources of funding for our share repurchase program. Based on the anticipated amounts to be generated from those sources of funds in relation to the remaining authorization approved by our Board under the June 2012 share repurchase program, we do not expect that future share repurchases will have a material impact on our short-term or long-term liquidity.

The following table presents the total number of shares of our common stock that we purchased during the fourth quarter of fiscal 2013, the average price paid per share, the number of shares that we purchased as part of our publicly announced repurchase program, and the approximate dollar value of shares that still could have been purchased at the end of the applicable fiscal period, pursuant to our June 2012 share repurchase program:

Subsequent to December 31, 2013, we repurchased no additional shares of our common stock. As of February 26, 2014, we have the authorization to repurchase up to $23.9 million of our common stock under the program.

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Securities Authorized for Issuance under Equity Compensation Plans

The table below contains information about securities authorized for issuance under our 2011 Incentive Compensation Plan (the “2011 Plan”). The features of the 2011 Plan are disclosed further in Note M to our consolidated Financial Statements in Part II, Item 8 of this Annual Report on Form 10-K.

U.S. Silica Holdings, Inc. Comparative Stock Performance Graph

The information contained in this U.S. Silica Holdings, Inc. Comparative Stock Performance Graph section shall not be deemed to be "soliciting material" or "filed" or incorporated by reference in future filings with the SEC, or subject to the liabilities of Section 18 of the Exchange Act, except to the extent that we specifically incorporate it by reference into a document filed under the Securities Act or the Exchange Act.

The graph below compares the cumulative total shareholder return on our common stock, the cumulative total return on the Russell 3000 Index and the Standard and Poor's SmallCap 600 GICS Oil & Gas Equipment & Services Sub-Industry index since January 31, 2012, the first day our stock traded on the NYSE.

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The graph assumes $100 was invested on January 31, 2012, the first day our stock was traded on the NYSE, in our common stock, the Russell 3000 and the Standard and Poor's SmallCap 600 GICS Oil & Gas Equipment & Services Sub-Industry Index. The cumulative total return assumes the reinvestment of all dividends.

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The following table and discussion sets forth our consolidated statement of operations data for the periods presented. The results of operations by segment are discussed in further detail following this combined overview.

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The following discussion and analysis of our financial condition and results of operations should be read together with Item 6, "Selected Financial Data," the description of the business appearing in Item 1, “Business,” of this report, and the Consolidated Financial Statements in Item 8 of this Annual Report on Form 10-K and the related notes included elsewhere in this report. This discussion contains forward-looking statements as a result of many factors, including those set forth under Item 1, “Business—Forward-Looking Statements” and Item 1A, "Risk Factors," and elsewhere in this Annual Report on Form 10-K. These statements are based on current expectations and assumptions that are subject to risks and uncertainties. Actual results could differ materially from those discussed in or implied by forward-looking statements. Factors that could cause or contribute to these differences include those discussed below and elsewhere in this report, particularly in Item 1A, "Risk Factors."

Management’s discussion and analysis of financial condition and results of operations (“MD&A”), is organized into the following sections:

In addition to disclosing financial results that are determined in accordance with United States generally accepted accounting principles, or GAAP, we also use certain non-GAAP financial information, such as:

Segment contribution margin and Adjusted EBITDA are not recognized measures under GAAP and should not be considered alternatives to or superior to expense and profitability measures derived in accordance with GAAP. For a detailed description of the non-GAAP measures used in this MD&A, please see the discussion under “How We Evaluate Our Business” and “Non-GAAP Financial Performance Measures”.

Overview

We are one of the largest domestic producers of commercial silica, a specialized mineral that is a critical input into a variety of attractive end markets. During our 113-year history, we have developed core competencies in mining, processing, logistics and materials science that enable us to produce and cost-effectively deliver over 250 products to customers across these markets. In our largest end market, oil and gas proppants, our frac sand is used to stimulate and maintain the flow of hydrocarbons in oil and natural gas wells. This segment of our business is experiencing rapid growth due to recent technological advances in the hydraulic fracturing process, which have made the extraction of large volumes of oil and natural gas from U.S. shale formations economically feasible. Our silica is also used as an economically irreplaceable raw material in a wide range of industrial applications, including glassmaking and chemical manufacturing. Additionally, in recent years a number of

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attractive new end markets have developed for our high-margin, performance silica products, including high-performance glass, specialty coatings, polymer additives and geothermal energy systems.

As of February 26, 2014, we operate 15 facilities across the United States and control 297 million tons of reserves. We own one of the largest frac sand processing plants in the United States and control approximately 138 million tons of reserves that can be processed to meet American Petroleum Institute (API) frac sand size specifications. Our operations are organized into two segments based on end markets served: (1) Oil & Gas Proppants and (2) Industrial & Specialty Products. Our segments are complementary because our ability to sell to a wide range of customers across end markets allows us to maximize recovery rates in our mining operations, optimize our asset utilization and reduce the cyclicality of our earnings.

Recent Trends and Outlook

U.S. demand for industrial silica has been growing steadily. According to The Freedonia Group, Inc. (“Freedonia”), demand for industrial silica sand grew at a 4% compound annual growth rate (“CAGR”) from 2001 to 2011. This increase in demand was driven primarily by hydraulic fracturing, which grew at a 27% CAGR from 2001 to 2011, according to the most recent related Freedonia report dated October 2012. More recently, the recovery of the U.S. housing and automotive markets has also positively affected silica related to those markets such as glass, building materials, foundry and fillers and extenders. Trends driving the acceleration in demand include:

Our Strategy

The key drivers of our growth strategy include:

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How We Generate Our Sales

We derive our sales by mining and processing minerals that our customers purchase for various uses. Our sales are primarily a function of the price per ton realized and the volumes sold. In some instances, our sales also include a charge for transportation services we provide to our customers. Our transportation revenue fluctuates based on a number of factors, including the volume of product we transport under contract, service agreements with our customers, the mode of transportation utilized and the distance between our plants and customers.

We primarily sell our products under short-term price agreements or at prevailing market rates. For a limited number of customers, we sell under long-term, competitively-bid contracts. As of February 26, 2014, we have five take-or-pay supply agreements with five of our customers in the Oil & Gas Proppants segment with initial terms expiring between 2014 and 2016. These agreements define, among other commitments, the volume of product that our customers must purchase, the volume of product that we must provide and the price that we will charge and that our customers will pay for each product. As discussed in Part I, Item 1A, “Risk Factors—A large portion of our sales is generated by our top customers, and the loss of, or significant reduction in, purchases by our largest customers could adversely affect our operations,” these customers may not continue to purchase the same levels of product in the future due to a variety of reasons, contract requirements notwithstanding. Prices under these agreements are generally fixed and subject to upward adjustment in response to certain cost increases. As a result, our realized prices may not grow at rates consistent with broader industry pricing. For example, during periods of rapid price growth, our realized prices may grow more slowly than those of competitors, and during periods of price decline, our realized prices may outperform industry averages. Additionally, at the time the take-or-pay supply agreements were signed, two of these customers provided advance payments for future shipments aggregating $27.0 million. A percentage of these advance payments was recognized as revenue with each ton of applicable product shipped to the customer. Collectively, sales to customers with supply agreements accounted for 40%, 31% and 17% of our total sales in 2013, 2012 and 2011, respectively. Although sales under supply agreements, as opposed to short-term price agreements or at prevailing spot market rates, result in us realizing lower margins than we otherwise might during periods of high market prices, we believe such lower margins are offset by the benefits derived from the product mix and sales volume stability afforded by such supply agreements.

We invoice the majority of our clients on a per shipment basis, although for some larger customers, we consolidate invoices weekly or monthly. The amounts invoiced include the amount charged for the product, transportation costs (if paid by us) and costs for additional services as applicable, such as costs related to transload the product from railcars to trucks for delivery to the customer site.

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The Costs of Conducting Our Business