On December 31, 2012, U.S. Silica Holdings, Inc., through certain of its subsidiaries as borrowers and guarantors, entered into Amendment No. 6 to the ABL Loan and Security Agreement with Wells Fargo Bank, National Association, as agent and the lenders named therein. The Amendment increases the commitments under the Agreement from $35 million to $50 million, and the letter of credit sublimit from $15 million to $20 million; provided, however, that the aggregate principal amount of the loans and letters of credit obligations outstanding at any one time shall not exceed the borrowing base as calculated pursuant to the Agreement.

The Amendment also extends the termination date of the Agreement from October 31, 2015 to October 31, 2016, reduces pricing and fees on borrowings, letters of credit and unused commitments and adds an additional subsidiary as a co-borrower.