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S ZEN )C 0 ?m 4P En YY Seneca Coal Company <br />July 3, 2008 <br />Mr. Dan Mathews <br />Division of Reclamation, Mining and Safety <br />101 South 3rd, Suite 301 <br />Grand Junction, CO 81501 RECEIVED <br />(970) 243-1571 <br />JUL 0 7 2008 <br />RE: Yoast Mine Permit No. C-94=082 _ _-_DiviSion of_Recla0laWn, <br />- - `Addendum -to 2008 Rill 8& Gully Survey Mk" and $2fiity <br />Mr. Mathews, <br />Seneca Coal Company (SCC) is submitting this package in response to items requested in your Yoast Mine Inspection <br />Report, dated 6/18/08. <br />• Please submit an addendum to the 2008 Kill and Guly Survey addressing the following (submit by firly 20, 2008, Repairs ttrill <br />need to be completed during 2008 field season): <br />1. Mining/reclamation practices and/orground conditions that may have caused the 25 foot deep crater on the mine backfill. Address <br />potential subsidence due to highwall mining <br />Response: It is SCC's belief that buried snow/ice near the end wall of the pit is the contributing factors that <br />resulted in this crater. As can be seen along most of the highwalls and endwalls there are slides and slumps <br />occurring due to; small areas of voids along the walls; differential settlement at the contact between consolidated <br />and unconsolidated materials; and the extraordinary amount of moisture from the snowmelt this spring. <br />SCC has reviewed the location of the crater in relation to the highwall miner activity and has determined that the <br />crater is located down-gradient from the nearest hole drilled by the highwall miner <br />-- - SCC-will backfill-and-regrade-theimme'diate Area "and reseed-the diifurbance. The minor amount of regrading <br />needed will not significantly change the overall post-mining topography. <br />2. Repair measures that will be taken to prevent a me umme of the severe erosion along and ai#acent to channel I'PM-8. More <br />generally, address permanent channel construction measures that will be taken to guard against the problem of channel blockage by <br />ice during snovmelt, vhich appears to have resulted in channel excursions and sidecutting in numerous locations along permanent <br />channels. <br />Response: SCC proposes to repair/reconfigure the approved channel YPM-8 and regrade the erosional features <br />outside the channels. As the DRAB inspector saw in the field the channel itself remained intact, the erosion <br />occurred outside the channel itself. <br />Seneca Coal Company e P.O. Box 670 • Hayden, Colorado 81639 <br />Telephone (970) 276-5219 9 FAX (970) 276-5222