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U <br /> <br />The sampling pit should be covered to prevent contamination. The following <br />stipulation is hereby attached to this permit approval: <br />KERB COAL IS DIRECTED TO MONITOR WATER QUALITY FROM THE SPRING AT THE OLD SUDDUTH <br />MINE QUARTERLY FOR ONE YEAR, ACCORDING TO THE SAME PARAMETERS AS OTHER HYDROLOGIC <br />MONITORING. RESULTS ARE TO BE SUBM_TTTED TO THIS DIVISION. <br />VII. Assessment of Probable Cumulative Impacts (2.05.6(3)) <br />Surface Water <br />This aces~ssment is based upon the applicant's statement of probable hydrologic <br />consequences which has been summarized for inclusion in this assessment, and <br />the hydrologic and geologic information contained in the Kerr application. All <br />of the effects identified are assumed to be short-termed. However, the applicant <br />is undertaking a continuing surface and groundwater monitoring program to verify <br />the analysis of probable hydrologic effects. Future reviews will reassess the <br />cumulative hydrologic effects in this area using improved techniques, additional <br />baseline data, new research, and the results of surface and ground water monitor- <br />ing programs. <br />Anticipated coal mining in the general area included the existing and proposed <br />Kerr surface mining operations, and the existing Wyoming Fuels mine. Additional <br />mining assumes that Wyoming Fuels would aquire leases to mine additional coal in <br />Section 10, TBN, R78W, and that Kerr's mining activities would continue along <br />the other limb of the Johnny Moore synline. <br />This scenario involves the disturbance of 846 acres in Bolton Draw, 71 acres in <br />Bush Draw, 200 acres in Williams Draw, and 50 acres in Sudduth Draw. Calculations <br />assume worst case conditions, the drainages are analyzed as if all the proposed <br />disturbances would occur simultaneously. Under actual conditions, mining would <br />be phased. AS a result, the actual effects should be less. <br />Effects <br />Two of the expected hydrologic effects are not quantifiable at present. Surface <br />water monitoring at the Xerr mine siteindicates that the on balance in the surface <br />waters would shift to a sodium-bicarbonate and magnesium-sulfate type water. <br />Water chemistry should return to natural conditions following reclamation. This <br />effect would be most persistentin Bolton Draw which receives most of the Honing <br />activities. In Sudduth Draw which would have the Ieast disturbance the change <br />s/o old provably be undetectable . <br />The effects of releasing sediment deficient waters from sediment ponds would <br />probably not have an additive effect on the receiving streams. Under ephemeral <br />regimes the water released would quickly infiltrate channel alluvium, and any <br />downcutting would be limited to the point of discharge and immediately downstream. <br />Unless large amountsof pit water are discharged through sediment ponds, and the <br />spot effects are left unmitigated, the receiving streams should not be af=ected. <br />Other surface water effects are euantifiable. Under the proposed scenario, Bolton <br />Draw surface flow (annual yield) would be reduced by 2a% because of pond detention <br />during the mining phase of the operations. Following successful reclamation, <br />surface flows would be increased by 6% of the annual yield. During operations, <br />salt loading would occur at a rate of 90.5 kq/yr. <br />In Bush Uraw, sediment pond detention would be 7~ of the annual yield, the post- <br />-6- <br />