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Chapter IV <br /> The impacts incurred by ground water resources as a result of the proposed mining <br /> operations are expected to be insignificant. However, several slight changes in the <br /> hydrologic system are expected: the ground water quality of alluvial ground water <br /> located adjacent to the coal processing waste and tunnel rock piles will become slightly <br /> degraded; and slight mixing of ground waters from previously unconnected aquifers <br /> may occur as a result of the proposed rock tunnel. None of these potential impacts are <br /> expected to cause material damage to ground waters inthe Coal Basin area. Each is <br /> discussed in greater detail below. <br /> The disposal of mine and processing waste materials at the mine have the potential to <br /> degrade the quality of the alluvial ground water of Coal Creek. A geochemical analysis <br /> of the roof and floor rock and coal (see page III-D-37 of the permit application) failed to <br /> indicate any toxic or hazardous materials. In addition, seven years of ground and <br /> surface water monitoring, during which time similar wastes were being disposed of, <br /> indicate that water quality has not been materially damaged. Therefore, presently this <br /> potential impact is insignificant. The alluvial ground waters and surface waters will be <br /> monitored during and after mining to detect any further degradation of water quality if it <br /> occurs. <br /> The Adit/Rock Tunnel cuts through the Cozette and Rollins sandstones and inflows of <br /> ground water from these potential aquifers have entered the Adit/Rock Tunnel, although <br /> the rates of inflow have been insignificant, based on measurements which range from 5 <br /> to 15 GPM. Inflows increase slightly during the spring snowmelt in conjunction with <br /> increases in aquifer recharge. Any inflows from these sandstones will be pumped out <br /> of the tunnel, thus sustaining any base flow losses to the streams. As previously <br /> • discussed these sandstones are too deep to be utilized as a water supply, and <br /> therefore no material damage will occur as the result of dewatering these sandstones. <br /> During low flows, fall and winter, water quality samples indicate some elevation of TDS, <br /> sulfates and SAR. It is believed this is attributable to the Nos. 1 and 2 mine discharges <br /> and the old coal refuse pile. All stream flows are low in the spring/summer, so dilution <br /> is less. None of the numbers are high, but do show an elevation. Dilution does occur <br /> downstream of the mine property before the junction with the Crystal River. See Coal <br /> Creek at mouth MCR station No. 1 and also C.D.H. station CC-1 Vol. 5, Ch. 3, App. <br /> III-E-5. See also CDH stations CR=5 and C-R=6-Crystal-River-above--and-below the-- -- -- -- - <br /> confluence with Coal Creek. <br /> Surface and ground water samples taken in Coal Basin for more than a decade indicate <br /> no significant impact to or degradation of water quality in the Coal Basin drainage. <br /> Further improvement is anticipated in years to come with a decrease of surface activity <br /> as a result of the modernization of operations. <br /> 14 <br />