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several engineered seals located within the mine designed to withstand <br />pre-mining head pressures. <br />MCC has conservatively estimated that the B Seam mine, including <br />Jumbo Mountain, and the existing F Seam mine would flood and fill in <br />139.6 yeazs. This estimate assumes no seepage or outflow and the worst <br />case maximum steady inflow for the F Seam mine and the median of the <br />5-year and life-of--mine, worst case maximum steady inflows for the B <br />Seam mine. <br />Water moves downslope and discharges as seeps and springs. It also <br />appears that mine inflows are controlled by the amount of precipitation <br />(mostly snowmelt), depth of overburden and location and extent of <br />fracture zones and not by the extent of the underground workings. <br />Mountain Coal Company predicts that the West Elk Mine will have no <br />significant impact on the quality and quantity of groundwater and <br />springs. Representative water quality samples from wells located in the <br />Lower Coal Member show that groundwater is suitable for dischazge to <br />the North Fork. <br />The B Seam lies ten feet above the Rollins Sandstone unit. The operator <br />states that based on data from the mining and reclamation plan and recent <br />drilling, it is possible that the North Fork of the Gunnison River <br />recharges and receives dischazge from the Rollins Sandstone in a small <br />area on the northern edge of the West Elk property, although evidence <br />from a well in the Rollins down-gradient of the river shows that is <br />unlikely. <br />The Rollins Sandstone is considered a marginal aquifer in terms of yield <br />and water quality and, to the Division's knowledge, has no points of <br />usage in the mine vicinity The Rollins sandstone is monitored by Oxbow <br />Mining LLC at a point up-gradient of their Sanborn Creek operation and <br />down-gradient of West Elk. Since the Somerset Mine has been active <br />since 1906, any potential for severe water quality impact would probably <br />be evident by this time. The water quality data for R-1, a well completed <br />in Rollins Sandstone and drilled by Mountain Coal Company in 1976, <br />indicates total dissolved solids generally outside the range acceptable for <br />drinking water. MCC originally had completed two wells in the Rollins <br />Sandstone to monitor water levels and provide water quality data. Based <br />on information contained in the Annual Hydrology Reports prepazed for <br />the mine, mining activities in both the F and B seams appear to have had <br />no impact on groundwater in the Rollins Sandstone to date. These wells <br />were removed from the program. Data aze now available from the up- <br />gradient Rollins well at the Sanborn Creek mine (SC-1). <br />53 <br />