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Mining Plan Exhibit D <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 <br /> later 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 <br /> lasted 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. Mining will <br /> take place to a total depth averaging 25 feet. Higher overburden exists in the southeast comer of the <br /> property, which will be part of the facilities area which will not be mined. Sand and gravel are the <br /> products mined from this site. Topsoil and overburden are stripped in advance of mining with a track <br /> hoe and truck. Gravel is mined out with a front-end loader, and directly transported into a truck or the <br /> crusher. In any mining phase that has a wetland footprint; material will be excavated via track hoe <br /> directly into a haul truck. No temporary stockpile is created in any phase with wetland footprints. Any <br /> stockpiling that does take place will be on the established processing site on the south side of the pit, <br /> or in mining phases that are free of wetland footprints. <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 Map <br /> C-3. The raw gravel material will be excavated to the bedrock surface and loaded into a crusher& <br /> screening plant and/or washing plant where various sizes of product will be sorted and placed in <br /> separate stockpiles. <br /> Crushing and screening activities will take place in the processing area in the southeast corner of the <br /> mine. <br /> White River City <br /> July 2022 D_1 Lewicki&Associates <br />