Laserfiche WebLink
2. PHC: Groundwater inflow into the mine will be very low. <br />Mining in the B Seam encountered only small flows of water and the mine is essentially dry. <br />Typical inflows are in the order of 1 to 8 gpm with occasional short term increases when <br />localized perched water tables are encountered. <br />3. PHC: The construction of surface facilities associated with the mine will result in <br />temporary increases in the suspended solids concentration of the adjacent and receiving <br />stream. <br />The temporary increase predicted in the PHC section of the Deserado Mine permit would have <br />most likely occurred during construction of the facilities area. Although the prediction no <br />longer applies, the effect of sedimentation ponds on the site is to reduce TSS to levels lower <br />than they would be during a storm event. Discharge Monitoring Reports during the 2009 water <br />year showed consistently low suspended solids. <br />4. PHC: Mine inflows are predicted not to exceed 5 to 10 gpm. <br />Incidental leakage into the mine site includes leakage from water lines, dust control, and wash- <br />down water. The 2009 AHR lists 6.81 gpm mine inflow from the incidental water. <br />5. PHC: Very little water will be pumped to the surface from the underground mine. <br />No water has been pumped from the underground workings since January 10, 1996. During the <br />1996-1997 periods, Deserado Mine began disposing of the prep plant thickener water in the <br />mined out area of the D-seam. <br />6. PHC: The local groundwater table may be lowered as mining proceeds. <br />The 2009 AHR showed a decline in piezometric level in wells in close proximity to mine <br />workings. Five monitoring wells have turned dry as a result of being mined through. Two <br />monitoring wells showed a rise in water levels from the 2008-2009 water year and ten <br />monitoring wells showed a decrease in the water table, with well 22-3M showing no change. <br />7. PHC: The effects of subsidence in Red Wash and in Scullion Gulch will be shot-lived. <br />As projected, subsidence in Red Wash initially resulted in water ponding in the stream bottom. <br />The high content of silt and clay carried by Red Wash rapidly filled the ponds. The silt and <br />clay layers have sealed any cracks that formed in the alluvium as the result of subsidence. The <br />2009 AHR reports that no surface hydrologic consequences were observed due to subsidence. <br />8. Refuse disposal effects on surface and groundwater systems is expected to be minimal. <br />The 2009 AHR included no data on this prediction. There was no discharge of surface water <br />from ponds RP-1, RP-2/3/4, and RP-5 treating run-off from the waste piles. Seeps and springs <br />are absent in the refuse disposal area and the entire site receives low precipitation. Overall, the