1998-07-02_INSPECTION - M1977493

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MINE ID # OR PROSPECTING ID # M-77-493 INSPECTION DATE 7/2/98 INSPECTOR'S INITIALS ACS OBSERVATIONS This inspection was conducted primarily to assess environmental protection facilities and storm water controls upgradient of Eagle Park Reservoir. These facilities and controls are pertinent to the Division's review of pending permit revision SR-02, which is a request for a finding that the post mining land use of developed water resources has been established in Eagle Park Reservoir. There are two primary areas of seepage of process water below Robinson Lake. The upper seepage area consists of toe seepage from the dam and is most likely related to internal drainage features incorporated into the design and construction of the dam. It was agreed that the operator would search records for a cross section illustrating the internal structure of the dam and provide copies of available information to the Division. Robinson dam toe seepage is collected and routed to the Robinson seep pifmp back sump which has been described in previous inspection reports and is an approved environmental protection facility. The overflow culvert that was previously present in the Robinson seep collection sump has been removed, and the downstream side berm of the sump has been built up and stabilized in the area of the removed culvert. Seep water collected in the sump is returned to Robinson Lake via either or both of two pumps and two return pipelines. The second area of Robinson Lake seepage is located in a low, bowl shaped area below the Robinson seep collection sump, but topographically above the Robinson ground water cutoff wall. These seeps are routed to a basin that has been recently excavated just above the concrete ground water cutoff wall. The collected seeps are impounded against the upstream face of the concrete cut off wall, which has been exposed to a depth of approximately three feet. The seepage impounded in the basin infiltrates into the ground water cut off pump gallery and is returned to Robinson Lake. As a contingency measure, a pump has been placed into the ground water cut of wall basin that can pump water from the basin back the Robinson seep collection sump. At the time of this inspection, there was very little water impounded behind the cut of wall, and it appears that the capacity of the basin and the rate of infiltration to the pump back gallery is adequate to contain the lower Robinson Lake seeps. Since 1998 was a relatively light snowmelt year at Climax, the sizing of the ground water cutoff wall basin has not been subjected to worst case, high runoff conditions. However, with the contingency available to pump out of this basin, containment of Robinson Lake seepage is assured, and the basin can be enlarged or other containment measures implemented if warranted based on observations of performance during normal or high runoff years. Ditchwork and culverts have been installed upgradient of the Robinson seep collection sump and the ground water cutoff wall for the purpose of diverting clean runoff around these facilities. There are areas of non point source pollution, roads and related ground disturbance, in the source areas for the diverted runoff. Roads that are no longer needed are being reclaimed by backfilling and revegetation. One such road was inspected. The backfilling has essentially restored original contour and the second year growth of vegetation was showing a good percentage of cover. The area between the Chalk Mountain intercept and the Eagle Park Reservoir was inspected. This area is located above the steep slopes that are present along the south shore of the reservoir at its east end. In order to enhance the stability of this steep slope, Climax has committed to routing runoff around the steep slope area. However, it was observed that runoff from the road along the south reservoir perimeter would flow on to the steep south shore slope. Since this site inspection triggers the 60 day period during which the Division must make a decision on revision SR-02, it was agreed that storm water control improvements would be implemented along the south reservoir shore within that 60 day period, and the Division would reinspect the site. It was also observed that small amounts of trash, in the form of wood, steel cable, etc. , are scattered in areas that are below the ultimate high water line of Eagle Park Reservoir. It was agreed that these areas would be cleaned-up prior to the Division's reinspection within the next 60 days. Given the current rate of inflows to the reservoir and the water level in the reservoir, it does not appear that it will be filled this season. The 4-Dam seep collection ponds were inspected. It was observed that improved, deepened ditch work had been installed to route runoff around the collection ponds. It was further observed