U.S. Silica's SandBox Unit Wins Again at the Patent Office on Key Patent Claims

KATY, Texas, March 14, 2019 /PRNewswire/ -- U.S. Silica Holdings, Inc. (NYSE: SLCA) announced today that the United States Patent and Trademark Office has confirmed several additional patent claims covering fundamental aspects of technology owned by its SandBox Logistics™ business unit, continuing to validate the strength of the SandBox patent portfolio. These wins mean that Proppant Express Investments, LLC (PropX) is judicially barred from making the same or similar invalidity arguments in any future infringement proceedings involving these patents. 

"We are very pleased that the SandBox patent portfolio continues to hold up so well against challenges from PropX,'' said Bryan Shinn, U.S. Silica president and chief executive officer. ''We've now seen the Patent Office uphold key claims in three of the four IPRs initiated by PropX, including claims central to our underlying infringement action against PropX. Our success rate in these IPRs is well above the statistical norm and positions us extremely well in our ongoing action against PropX,'' he added.

About U.S. Silica

U.S. Silica Holdings, Inc. is a performance materials company and is a member of the Russell 2000. The Company is a leading producer of commercial silica used in the oil and gas industry, and in a wide range of industrial applications. Over its 119-year history, U.S. Silica has developed core competencies in mining, processing, logistics and materials science that enable it to produce and cost-effectively deliver over 1,500 diversified products to customers across our end markets. U.S. Silica's wholly-owned subsidiaries include EP Minerals and SandBox Logistics™. EP Minerals is an industry leader in the production of products derived from diatomaceous earth, perlite, engineered clays, and non-activated clays. SandBox Logistics™ is a state-of-the-art leader in proppant storage, handling and well-site delivery, dedicated to making proppant logistics cleaner, safer and more efficient. The Company currently operates 27 production facilities. The Company is headquartered in Katy, Texas and has offices in Frederick, Maryland, Reno, Nevada and Chicago, Illinois.

U.S. Silica Holdings, Inc.

Michael Lawson
Vice President of Investor Relations and Corporate Communications
(301) 682-0304
lawsonm@ussilica.com

Nick Shaver
Investor Relations Manager
281-394-9630
shavern@ussilica.com    

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SOURCE U.S. Silica Holdings, Inc.