2010-08-02_REVISION - M1977300 (34)

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Environmental Protection Plan, Schwartzwalder Mine 1-2 • Dewatering of the spiral decline ceased in September 1998, when the pumps were shut off at the bottom of the decline (approximately 2,200 feet), and the lower workings of the mine were allowed to refill to the 19 Level. Mining operations continued until May 2000, when the pumps were shut off on the 19 Level and 7 Level, and the mine was allowed to flood. (b) Mine Layout The mine was accessed through the Steve Level, which occurs at approximately 6,602 feet elevation in North American Datum [NADI 27 coordinates or 6,550 feet elevation in mine coordinates . Two portals exist on the Steve Level, which provided for normal mine access (the Steve Portal) and emergency egress (the Pierce Adit). Several older workings were developed above the Steve Level. The Charlie and Minnesota levels, which are 119 and 226 feet above the Steve Level, respectively, intercept the CV glory hole and represent the bulk of the upper workings (Figure 1-1). Additionally, the Upper Level and LBJ Level daylight on the hillside. The elevations of the upper levels are given in Table 1-1. Table 1-1. Elevations of Upper Levels at the Schwartmalder Mine • LEVEL MINE ELEVATION NAD27 ELEVATION Upper 6,895 6,947 LBJ 6,835 6,887 Minnesota 6,776 6,828 CV 6,739 6,791 Charlie 6,669 6,721 Steve 6,550 6,602 Below the Steve Level, the levels are identified according to their depth (in hundreds of feet). The most extensive workings are on the 19 Level, with significant development on the 7, 9, and 15 through 17 levels. The total mine depth is 2,222 feet from the Steve Level portal to the bottom of the spiral decline The mine was ventilated through the Main and Jeffrey Shafts. The Main vent shaft extends from ground surface at the top of the hillside (elevation 7,294 ft, NAD 27) to the 7 Level. The Jeffrey vent shaft extends from ground surface near the Charlie level to the 11 Level. Areas that were not actively worked were typically bulkheaded during operations, to minimize radon gas exposure. During operations, the Schwartzwalder Mine was kept dry by pumping water from the lower levels of the mine. Water was collected on the 19 Level, pumped to the 7 level, and then pumped to the surface where it was treated and discharged to Ralston Creek. The water treatment plant also processed water from four sumps in the alluvium and fill. Combined pumping from the sumps averaged approximately 100 gpm, with seasonal lows of 35 gpm and highs of 400 gpm (Section 8(b)(i).3). 4109C.100731 Whetstone Associates 6