2012-02-24_REVISION - M1999120 (7)

Home Browse Search

MINING PLAN EXHIBIT D (CONT) perimeter of each additional mine area prior to commencement of mining in the new phases. This isolates each mining area from the surrounding groundwater table and allows for dry- mining of each mine area. However, if a slurry wall is not feasible, the Applicant will utilize a compacted clay liner to seal the pits for the end use as water storage. Design of the liner will follow the State Engineer's Guidelines also. Slurry wall design documents were submitted and deemed adequate to the Division in 1999. Slurry walls installed using this design have been con- structed successfully on the 5 lined areas currently complete. Additional monitoring holes will be installed along the eastern and southern sides of the six stages on the south end of the amendment area. Ground water monitoring is discussed in more detail in EXHIBIT G. Prior to mining moving into those areas just north of WCR 14.5, the Plant Site may be moved to that side of the mine adjacent to the southern access road that now serves the Lupton Meadows Reservoir mine. Mining operations within each new phase area will include topsoil and overburden stripping, and excavation of dewatering trenches, and settling ponds. Raw materials will be excavated with excavators, front -end loaders, scrapers and /or bulldozers. As areas are cleared and stripped, previously mined slopes will receive backfill material to establish the permanent design side slopes. Explosives will not be used at this operation. Adequate amounts of the stripped topsoil and overburden will be stockpiled for later use in reclamation. Topsoil and overbur- den stripped from subsequent mine areas may be placed directly on the seed bed in previous mine areas so it only has to be handled once and the disturbed areas will be concurrently reclaimed. Topsoil berms will be constructed and strategically located around the site for use as noise and visual screening barriers from neighboring properties. The exact location of topsoil and over burden piles are unknown at this time, so we have shown the approximate location on EXHIBIT C -1 - MINE PLAN MAP. Mining within each phase will begin once topsoil and over- burden has been removed from that phase area. Excavated materi- als (pit run) will be removed via front -end loaders, and may be loaded onto a field conveyor and transported back to the process- ing plant, or loaded into off -road haul trucks for transport to the plant site. Mined slopes will range from near vertical to 0.5:1, or as required by the Slope Stability Analysis and Setback Agreements (see EXHIBITS in the 2004 submittal) . As soon as mining limits have been reached in one phase area, reclamation of the pit edges within that phase area will begin. This will allow for concurrent backfilling of the pit perimeter with previously stripped overburden and /or material stripped from the next phase area to be mined. Access roads built during slurry wall con- struction and mining will be left as access roads around the reservoirs or for access to oil and gas wells on the site. Since we are combining two permitted areas we have areas in both mines that are partially mined and reclaimed. This includes 6