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San Joaquin County Community Project Description Development Department (backfilling of overburden and unusable fines after maximum excavation depth has been reached in each stage). The South Pit would be excavated to the depth of groundwater. Once excavation at the South Pit has encountered groundwater, excavation of Stage I of the North Pit would begin. Stage I of the North Pit would then be excavated to a depth of _ approximately 20 feet AMSL and would be used for storage of groundwater encountered during excavation of the South Pit. The South Pit would then be mined to design depth and groundwater would be pumped to Stage I of the North Pit. — After the South Pit reaches the maximum design depth, Stage I of the North Pit would be excavated to the depth of groundwater. The overburden and fines — encountered during excavation of Stage I would be used to backfill the South Pit to 15 feet above groundwater(approximately 60 feet deep). The South Pit would then be used for infiltration of groundwater encountered during excavation of — Stages I,II,and III of the North Pit. Once the South Pit has been backfilled, Stage I of the North Pit would be mined — to maximum design depth. Reclamation of Stage I would begin once the maximum design depth of Stage I has been reached. Simultaneous with reclamation of Stage I, excavation at Stage II would begin and the Stage II area — would be mined to the maximum design depth. Reclamation of Stage I would begin with backfilling the Stage with overburden and fines to 15 feet above groundwater. The overburden and fines would be used — to develop 1.5:1 side slopes along the perimeters of Stage I. Topsoil would then be reapplied to Stage I in accordance with the Reclamation Plan. Once the maximum design depth of Stage Il has been reached,excavation of Stage III would begin. Reclamation of Stage II would then begin in a manner similar to that in which operations progressed from Stage I to Stage H. As Stage — II is excavated to the maximum design depth, Stage II would be backfilled with overburden and fines to a depth of approximately 15 feet above groundwater. Topsoil would then be reapplied in accordance with the Reclamation Plan. Once T Stage III has reached the maximum design depth,reclamation of Stage III would begin. Stage III of the North Pit is proposed to be backfilled to groundwater level and used as pond for agricultural water storage. The pond will be _ approximately 25 acres in size. Concurrently, the South Pit would be backfilled to its pre-mining elevation and topsoil would be reapplied in accordance with the Reclamation Plan. In the case of Wet Pit Operations,once excavation at each pit or stage reaches groundwater,material would be removed with a dragline or dredge and no dewatering(pumping of groundwater out of the active pit)would occur. Quarry — slopes would be the same as for dry pit operations. The South Pit would be backfilled to the pre-mining topography and the North Pit would be backfilled to a uniform grade 15 feet above groundwater. Sequencing would be the same as for dry mining,except that no water storage basin would be created for use DeSilva Gates Quarry Project — Draft Environmental Impact Report 2-6 AS 0510505