2004-02-27_REVISION - M1977424 - Laserfiche WebLink

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Logan Wash Mine TR No. 4 welded between the two main angle irons to form a framed square azea that will hold the ventilation pipe. The ventilation pipe will be a 6-inch diameter steel pipe welded directly on to the steel plate cover. The ventilation pipe will extend approximately 5 ft from the steel plate cover and 3 ft above final grade. The vent pipe will have an 90-degree elbow on the top end and the end opening will be covered by welding on grated steel plating. Grade preparation will include 2 feet of cover with asub-soil material (waste-rock from the mine site) and 1 ft of top soil material. The entire disturbed surface will be reseeded in accordance with procedures consistent with Section 3.2 (Roads), or the area will be seeded by hand. Hand seeding will include broadcast seeding, raking of the seed into the soil, and the application of straw mulch (2,000 lbs/acre). The straw will be crimped into the soil using a mechanical crimper or with hand tools, Current Status The vent shafr closure has been reclaimed as described above during the fall of 2003. 6.0 Portal Closure The initial Plan did not discuss the details of portal closure at the mine. The Plan simply stated that the "portals would be blocked and sealed." Several portals have been sealed with earth plugs since the mine became inactive in 1991. These include portals of the U-1 and U-2 drifts on the Upper Bench, and portals of the L-2 and L-3 drifts on the Lower Bench. At the beginning of the summer of 2003 three portals remained open at the mine, the Research Mine Portal, the Daylight Portal, and the L-1 Portal. In September 2003, the Research Mine Portal and the Daylight Portal were sealed with 40-ft earth plugs. The L-1 Portal was sealed in November 2003. The following text describes the rationale and sealing methods used at the Research Mine and Daylight Portals and the L-1 Portal. It is important to note that the portal seal as designed and described for the Reseazch Mine is currently considered an interim closure until further information can be collected. OOSI intends to monitor the seal with regard to its function as a water tight seal. Should the earth plug seal prove to be effective in retaining water in the mine over time, OOSI may propose that the seal become the permanent, revegetated closure to the portal; no access to the mine will be possible. 6.1 Research Mine Portal (Area 4) Background The Research Mine Portal is located at an elevation of 7,700 ft immediately west of the gully forming the northeast-most head of Logan Wash (SE'/a NE'/4 Sec. 25, T. 7 S. R. 97 W.). The portal entrance is approximately 9-ft high and 16-ft wide. The portal is accessible by way of the main mine access road (the road passes over the existing Research Mine waste-rock dump). The Research Mine is the only underground working at the mine site that seasonally discharged mine water to the surface from the portal. This discharge has been and still is under a National Wes4em Water 8 Land, Inc.