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The underlying geologic formations in the general area of the permit include (from west to east) Early <br /> Tertiary intrusive and Tertiary intrusive rocks, pre-Cambrian schist and gneiss, and Pennsylvanian <br /> sedimentary rock. Groundwater discharge is only through the permitted discharge point from the mine <br /> tunnel. <br /> The groundwater at the London Mine was decreed non-tributary in 1986 under Water Decree W-83-14- <br /> 76 to a maximum flow of 7.4 CFS. MineWater LLC under Consent Order IC-160803 has been methodically <br /> dewatering the Leadville Dolomite formation to reduce intrusion of groundwater to the historic workings <br /> of the London Mine. <br /> MineWater has identified that the South London Dump located near the American Shaft is a source of <br /> contamination to the mine workings.The mining proposal intends to pull back waste from next to the <br /> Shaft and to eliminate run-on to the collapses adjacent to the Shaft,thereby further reducing cadmium <br /> and zinc contamination from the London Mine. <br /> The past 5 years since completion of the initial dewatering and mine tunnel remediation effort has <br /> resulted in large reductions in contamination discharged from the Mine.The graph below is extracted <br /> from the EPA ECHO facility database for the London Mine permit CO0038334 showing the major benefits <br /> achieved from work to-date. (Monthly dissolved zinc levels, in ppb, are shown in this graph, below.) <br /> (e) <br /> Figure 1 Zinc concentronons discharged from the London Mine,post 60 months <br />