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MINREC, INC. <br />2768 COMPASS DRIVE, SUITE 101 <br />GRAND JUNCTION, COLORADO 81506 <br />PRONE: (303) 245-4101, FA 242-7908 <br />BLUE RIBBON MINE <br />August 12, 1993 <br />C. E. Johnston <br />Division of Minerals and Geology <br />1313 Sherman St., Room 215 <br />Denver, CO 60203 <br />Re: Blue Ribbon Mine <br />NOV C-93-033 - Bench Repair Plan <br />Permit No. C-81-047 <br />Dear Ms. Johnston: <br />III IIIIIIIIIIIIIIII <br />999 <br />gEC-IVEr: <br />AUG 16 1993 <br />DIVIS IDli Of i4one~,,; a uuaioy}. <br />The Division's letter dated July 28, 1993, transmitted its preliminary <br />adequacy review for the mine bench repair plan. Following are Minrec's <br />responses to the Division's concerns: <br />1. No comment required. <br />2. In order to comment about the upward trend in the water table in the <br />bench, one has to look at different areas of the bench. In the area <br />of P-1 the water table has definitely shown an increase over the <br />years. However, even though the water level is quite high, the <br />bench in the area is stable. In the area of P-2 and P-3 a slight <br />increase in the water table is evident. In the area of P-4, again <br />a slight increase in the water table is evident. In the area of P-5 <br />and P-6 the water table has increased. I do not believe the data <br />indicates that the water level in the mine will continue to increase <br />to the point that the stability of the bench is compromised. <br />3. The two sources of water referred to in the discussion of the slope <br />failure were sources of water that were exposed in the coal waste. <br />They were "point" sources draining from the exposed coal waste. The <br />source of the water in the coal waste is believed to originate from <br />upslope along the colluvium bedrock contact. This water source, <br />snowmelt and precipitation, runs down from the slope above the slide <br />and percolates into the reclaimed mine bench. <br />4. The rock intercept drains will daylight on the face of the slope. <br />5. Enclosed are revised pages 113viii and 113ix which revise the <br />schedule to provide for the completion of the repair work by the end <br />of September. <br />Please call if you have any questions. <br />Sincerely, <br />~~ <br />im Stover, P.E. <br />Chief Engineer <br />Enclosures <br />