1993-05-26_REVISION - M1977378 (2)

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WELBORN DUFFORD BROWN 8 TOOLEY, P.C. Mr. J. David Holm May 26, 1993 Page Four through the Sunnyside Mine. Would this be subject to NPDES permitting requirements, or would it be handled under the same 1987 Division policy that covers other historic inactive mining portals in Colorado? Again, we request your position on this issue. (2) American Tunnel Below Property Line. Historic flows have occurred from the first 3500 ' of the lower portion of the American Tunnel since it was first driven in the 1920s. The pH of that water is generally acidic, and the flows derive from fractures and groundwater infiltration into the tunnel from near surface groundwater, snowmelt, and runoff in the surface geologic structures near the portal. There is no addition of pollutants or discharge of pollutants in that circumstance from any human activity, although there may be a "point source" at the portal. There has never been any mining activity in the area of the lower part of the tunnel, only the driving of the tunnel itself in the 1920s . Would an NPDES permit be required for that continuing flow, and who would be responsible for such a permit since it is below the property line of Sunnyside Gold? Alternatively, Sunnyside Gold, in conjunction with the Gold King property owner, could install a second or multiple additional seals in the American Tunnel to cut off flows from the portal. As above, the installation of these additional plugs would eventually result in ground water being backed up in the American Tunnel. The rising water pressure behind the plug would ultimately result in a return to an approximation of pre-mine ground-water flow directions. Ground water which presently flows from the American Tunnel will instead discharge at seeps and springs which were naturally present prior to mining. Would that return to natural hydrologic conditions result in any water quality permit requirements? (3) Lake Emma Reclamation. As part of the ongoing reclamation of the Lake Emma area, at an altitude of approximately 12,200' , surface runoff will be diverted by means of several ditches away from the former Lake Emma area so that it will not enter the mine workings. Additionally, certain "groundwater" in the loose rock near the ground surface in the basin will be intercepted and similarly diverted. Again, this is part of the planned reclamation in order to preclude part of the water in the Lake Emma basin from entering the mine workings. It would seem unrealistic to require a permit for any such structures and to monitor them into the future, given lack of mining activity and also given the climatic and