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piezometers located above the portals. In all cases the drop was not <br />greater than two feet. Water levels have changed very little since <br />January 1982. <br />MCC has submitted two plans for the sealing of the portals upon <br />closure of the mine. The first plan calls for sealing the portals to allow <br />gravity discharge of mine inflows. MCC anticipated, from water <br />samples taken in the Oliver Mine, and samples from existing inflow, <br />that mine waters will not be toxic. This plan calls for the construction <br />of a block wall at the portal and afour-inch PVC pipe to drain the <br />collected mine waters. The second plan is contingent on the mine <br />producing toxic mine waters. This plan calls for the construction of <br />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 fill in 193 <br />years. This estimate assumes no seepage or outflow and the worst case <br />maximum steady inflow for the F Seam mine and the median of the 5- <br />year and life-of-mine, worst case maximum steady inflows for the B <br />Seam mine based on assumptions from the two large in-flow events. <br />Water moves downslope and discharges as seeps and springs. It also <br />appears [hat some of the mine inflows are controlled by the amount of <br />precipitation (mostly snowmelt), depth of overburden and location and <br />extent of fracture zones and not by the extent of the underground <br />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 discharge to <br />the North Fork. <br />The B Seam, which will be mined during the next five year permit <br />term, lies ten feet above the Rollins Sandstone unit. The operator states <br />that based on data from the mining and reclamation plan and recent <br />drilling, it is reasonable to assume that the North Fork of the Gunnison <br />River recharges and receives discharge from [he Rollins Sandstone in a <br />small area on the northern edge of the West Elk property. It is evident <br />from available data that the Rollins behaves similarly to the Barren <br />Member and Coal members in the permit area except the extreme <br />northern edge where it has an alluvial contact with the North Fork. <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 />36 <br />