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The B Seam mine will not cause significant hydrologic impacts to <br /> groundwater systems in the five-year permit area based on the data <br /> provided. <br /> The majority of springs are located at or above the F Seam outcrop. A <br /> few springs have been identified between the E and F Seam outcrops. <br /> No springs have been identified below the E Seam outcrop. <br /> Monitoring of springs for baseline data and to assess impacts of mining <br /> in the F Seam has been carried out for the past fifteen years by MCC. <br /> Evidence to date indicates that mining has very little, if any, impact on <br /> spring flows. <br /> The depth of overburden where the B or the E seams will be mined in <br /> the area of the springs ranges from 400 to in excess of 1,000 feet. <br /> Based on experience in the F Seam and geotechnical work, the springs <br /> will not be affected significantly by mining in the B seam under these <br /> overburden depths. <br /> Some inflows to the mine are expected as mining proceeds under Lone <br /> Pine and Gribble Gulches as the valley features are fracture controlled. <br /> Inflows in these areas are estimated from 2 to 20 gpm. It is anticipated <br /> that the flow will be in the middle or lower end of the range. <br /> If flows into the mine approached the maximum estimated, 20 gpm, this <br /> would only be approximately 14 percent of the peak spring runoff flow. <br /> For this to occur or deplete spring flow, a direct fracture connection to <br /> the mine workings must occur and remain open. To date, this has not <br /> occurred in Lone Pine Gulch in the F Seam under cover as low as 120 <br /> feet. <br /> The water balance will not be significantly affected even if the <br /> maximum estimated inflows occur, since any mine inflows will <br /> ultimately be discharged back to the North Fork of the Gunnison. <br /> i. Refuse Material Disposal Impacts on Groundwater - <br /> Lower Refuse Disposal Area - Refuse is generated through the <br /> mining process and will be disposed of on the Lower Refuse <br /> Disposal and Refuse Pile Expansion sites. The lower refuse pile <br /> is permitted for permanent disposal of 1.09 million cubic yards <br /> of mine development waste, and sediment pond cleanout <br /> material. The refuse pile expansion is designed to hold 1.38 <br /> million tons of material over a life of 9.4 years. (The Refuse <br /> Pile Expansion is discussed in Permit volume 10B.) <br /> 40 <br />