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• Mining Plan Exhibit D <br />• <br />L <br />1. Geology <br />The site will mine a sand and gravel deposit which is an alluvium of the recent period of Quaternary <br />age. The alluvium is relatively shallow (less than 25 feet thick) and is underlain by the sandstones, <br />siltstones and mudstones of the Wasatch Formation. These sedimentary layers were formed when <br />uplifting Rocky Mountains to the east blocked eastward drainage during Tertiary time and the Uinta <br />Mountains blocked northward drainage and a very large lake formed in northwest Colorado, northeast <br />Utah and southwest Wyoming. This lake is referred to as Lake Uinta and it received all the washout <br />material from river floodplains and deltas from the mountains on all sides of the lake. Some of the later <br />mud which entered the lake became what is now the Green River Shale, which is noted for its oil <br />content. The Green River Shale forms the hills immediately south of the permit area. Lake Uinta lasted <br />for 6,500,000 years until further uplifts drained it. <br />2. General Mining Plan <br />The gravel zone is approximately 21 feet thick in an alluvial deposit and is overlain by topsoil which <br />averages 1.0 to 1.5 feet in thickness with approximately 2-8 feet of overburden until the gravel deposit <br />is reached. In the amendment area the overburden is expected to average 4 feet thick. Higher <br />overburden exists in the southeast corner of the property, which will be part of the facilities area which <br />will not be mined. Sand and gravel are the products mined from this site. Topsoil and overburden are <br />stripped in advance of mining with a track hoe and truck. The track hoe fills the truck directly from <br />excavation, no temporary stockpile is created. Gravel is mined out with a front end loader, and directly <br />transported into a truck or the crusher. Again, no temporary. stockpile is created. <br />The topsoil piles will have slopes no greater than 3H:1V. Overburden will also be removed and <br />stockpiled. Topsoil and overburden will be stockpiled separately but both material stockpiles will be <br />seeded with the dryland seed mix presented in Table E-3 of the Reclamation Plan after placement in <br />order to prevent erosion. No stockpiles will be placed within the wetland footprint areas shown on <br />Map C-3. The raw gravel material will be excavated to the bedrock surface and loaded into a crusher <br />White River City Pit, August 08 D-1