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<br />Since the cessation of mining operations, mine water is no longer being pumped <br />from the underground workings. As a result, the mine workings would <br />eventually fill with water, and the natural flow pattern would be restored. <br />Ground water passing through the abandoned workings would eventually discharge <br />to the glacial/alluvial aquifer. Water passing through the mine workings <br />would be expected to have a degraded water quality. Water found in adjacent <br />old mine workings is degraded (TDS, 10,509 mg/1, and SAR, 27). If water of <br />this quality discharged to the stream/alluvial aquifer system at the same rate <br />as maximum ground water inflow to the mine workings, the resulting water <br />quality in the stream under low flow conditions would be a TDS concentration <br />of 698 mg/1, and an SAR of 4. Water of this quality has a moderate salinity <br />hazard and a low sodium hazard. It is suitable for irrigation. <br />Other possible effects would not be expected to be significant. Increased <br />runoff and erosion from the surface disturbances associated with the mine <br />would be routed to a sediment pond. Water released from the pond would have <br />law sediment concentrations, but in some instances might be erosive. In this <br />case, however, surface flows are infrequent and the amount of water to be <br />released on a continuous basis is small (less than 0.17 cfs) and should not <br />cause significant downstream erosion. The pond contains 1.24 acre-feet of <br />dead storage, but this would normally be filled with water from the <br />underground workings so the pond would not decrease surface flow from the site. <br />Cumulative Hvdrolooic Impact Study Summary <br />The Red Canyon Mine is located in the Ward Creek watershed, two miles east of <br />the Tomahawk Mine, Both mines are located in the Tongue Creek watershed, a <br />tributary of the Gunnison River. <br />The major aquifer of use, the glacial-alluvial deposit is not continuous <br />between the two mines, as it is severed by the Ward Creek drainage. Any <br />projected impacts from either mine would not be cumulative. <br />While degradation of water quality and drawdowns are predicted at both mines <br />and could potentially overlap, material damage is not expected to occur. <br />Furthermore the potentially impacted strata is generally inaccessible for <br />water resource development as the strata dips north, eventually plunging deep <br />below the Piceance Basin. Water at such depths is uneconomical to develop. <br />The Red Canyo and Tomahawk Mines are two linear miles apart from o e another, <br />yet drainage ~rom each must travel four to five mi~es downstream be~ore <br />joining in the Tongue River. Both mines were projected to increase the <br />salinity of the streams in their drainage. Average TDS levels in Ward Creek <br />adjacent to the Red Canyon Mine, doubled from 99 mg/1 upstream of the <br />disturbed area to 194 mg/1 below the mine. Spoils discharges are projected to <br />be of such low quantity that they will have a negligible impact on the water <br />quality. Average TDS levels in Dirty George Creek, below the Tomahawk Mine, <br />average 421 mg/l. Both streams currently have water which is acceptable for <br />irrigation immediately below the mines. Additional dilution within the <br />watershed between the mines and their confluence on the Tongue River can only <br />improve the quality of the water. Should Quinn Coal Company develop an <br />underground mine at Tomahawk, cumulative impacts would need to be reassessed <br />with the advent of mine inflow discharges. <br />-12- <br />