Exhibit 10.18.8

RATIFICATION OF UNLIMITED GUARANTIES

This Ratification of Unlimited Guaranties is signed effective February 9, 2016, by the undersigned guarantors (collectively “Guarantors”) in connection with the Second Term Loan to be made by PLAINSCAPITAL BANK (“Lender”) to MAALT, L.P., a Texas limited partnership, and GHMR OPERATIONS, L.L.C., a Texas limited liability company (collectively “Borrowers”). The Second Term Loan is defined in and governed by the Loan Agreement dated June 15, 2014, among Borrowers and Lender, as now or hereafter amended, restated, replaced, supplemented, or otherwise modified, from time to time (the “Loan Agreement”). Capitalized terms not otherwise defined have the meanings assigned in the Loan Agreement.

Each of the Guarantors is legally obligated under an unlimited guaranty dated June 15, 2014, or dated February 11, 2015, executed by each of the respective Guarantors in favor of Lender in connection with the Loans to Borrowers (collectively the “Guaranties”).

By signing below, each of the Guarantors ratifies and confirms their respective Guaranty, acknowledges that their Guaranty is valid, subsisting, and binding upon the respective Guarantors, and agrees that their Guaranty guarantees payment of the Loans (including the Term Loan, Revolving Loan, and Second Term Loan), and the Notes (including the Term Note, Revolving Note, and Second Term Note).

As of the effective date of this Notice, Borrowers, Guarantors, and Lender have consummated a transaction pursuant to which Lender has agreed to make a loan or loans to Borrowers, to renew and extend an existing loan or loans to Borrowers, and to otherwise extend credit or make financial accommodations to or for the benefit of Borrowers, in an aggregate amount up to $17,807,269.78 (collectively, whether one or more, the “Loans”).

In connection with the Loans, Borrowers and Lender and the undersigned Guarantors have executed and delivered and may hereafter execute and deliver certain agreements, instruments, and documents (collectively hereinafter referred to as the “Written Loan Agreement”).

It is the intention of Borrowers, Lender, and Guarantors that this Notice be incorporated by reference into each of the written agreements, instruments, and documents comprising the Written Loan Agreement. Borrowers, Lender, and Guarantors each warrant and represent that the entire agreement made and existing by or among Borrowers, Lender, and Guarantors with respect to the Loan is and shall be contained within the Written Loan Agreement, as amended and supplemented hereby, and that no agreements or promises exist or shall exist by or among Borrowers, Lender, and Guarantors that are not reflected in the Written Loan Agreement.

THE WRITTEN LOAN AGREEMENT REPRESENTS THE FINAL AGREEMENT BETWEEN THE PARTIES AND MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR, CONTEMPORANEOUS, OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES.

THERE ARE NO UNWRITTEN AGREEMENTS BETWEEN THE PARTIES.

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