exhibit 10. 24 coal valley sales, llc 111 freeport road, pittsburgh, pa 15215 phone # # # - # # # - # # # # — fax # # # - # # # - # # # # june 5, 2017 scrubgrass generating company lp 2151 libson road kennerdell, pa 16374 dear mr. shaffer : reference is made to that certain waste disposal agreement by ant between scrubgrass generating company lp ( “ scrubgrass ” ) and coal valley sales llc ( “ coal valley ” ) dated february 12, 2002, as amended ( the “ agreement ” ). based on our recent discussions, coal valley will commit additional tonnage from the tassa stockpile it controls in irwin township, venango county as described in exhibit h to the agreement. further, any and all tassa waste coal shipped to scrubgrass will be considered part of the minimum payment provisions under section 5. 4 of the second amended agreement as of december 22, 2015. please indicate your acceptance of this waste coal pile to exhibit h by countersigning below. best regards, / s / joe anania joe anania cfo coal valley sales llc accepted and agreed to : scrubgrass generating company lp by : / s / r. j. shaffer r. j shaffer, plant manager third amendment to the waste disposal agreement this third amendment to the waste disposal agreement ( this “ amendment ” ) dated january 31, 2017, is by and between coal valley sales llc of 111 freeport road, pittsburgh, pa 15215, ( hereinafter called “ operator ” ), and scrubgrass generating company lp of 2151 lisbon road, kennerdell, pa 16374 ( hereinafter called “ scrubgrass ” ). whereas, operator and scrubgrass are parties to that certain waste disposal agreement dated february 12, 2002, amended by the letter agreement dated february 22, 2010, extended by facsimile transmission dated june 13, 2011 and amended by the second amendment dated december 22, 2015 ( the “ waste disposal agreement ” ) ; and whereas, operator and scrubgrass desire to amend the terms of the waste disposal agreement as provided herein. now therefore, the parties hereto, intending to be legally bound hereby an in consideration of promises contained herein, do hereby agree as follows : 1. defined terms. capitalized terms used herein without definition shall have the meanings ascribed to them in the waste disposal agreement.