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2 - 43 <br /> <br />• <br />2.4.2 Groundwater Inflow During Mining <br />Prior to the first permit term, numerous drillholes were drilled to an average depth of 50 <br />feet below the Cameo Coal Seam with virtually no water inflow realized and practically no <br />retention capability. The results of geophysical log interpretations in two exploration boreholes <br />(Appendix G) confirm the absence of water inflow potential.. Borehole 7-21.3, located on the <br />west side of the coal storage yard.: The hole was collared about ten feet below the Cameo seam <br />and was dry to the depth of 200 feet from the surface. This indicates that saturated sandstone <br />strata are about 210 feet below the Cameo Coal Seam and therefore beyond any possible <br />impact caused by mining activities. Borehole 7.15-3-3, located in the southwest quarter of <br />Section 15, just northeast of the permit boundary, was drilled about 38 feet below the Cameo <br />Coal Seam and was dry. Minor amounts of groundwater were encountered while mining in the <br />graben. Since the mine was generally progressing downdip, these inflows were pumped from <br />the mine or used in the mining process so that mining would not be hampered. A detailed <br />analysis of the inflows and the probable hydrologic consequence of the mining operation is <br />contained in Appendix N and in Section 2.4.4. Yearly hydrologic impact analysis that Grand <br />Valley submits to the Division are also useful when determining and monitoring any impact the <br />operation may have on the hydrology of the area. <br />As was the case during previous permit terms, all groundwater discharges will be in <br />• <br />accordance with the existing NPDES permit (CO-0038342). Results of sample analysis will be <br />submitted to CMLR as part of the quarterly reporting requirements. <br />NF <br />Volume 1 <br />4-29-96 <br />