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Rifle Gravel Pit#1 July 2023 <br /> • Final Reclamation (Phase 4) <br /> The stratum underlying the material to be mined is bedrock consisting of claystone and <br /> siltstone facies of the Wasatch Formation'. Gravel and sand will be the primary commodities <br /> that will be mined/extracted. These materials will support various construction projects in the <br /> region and will be available for sale. The excess overburden and topsoil will be retained to <br /> fill the pit in the instance mining ceases. The topsoil will be stabilized with an upland seed <br /> mix (minus the shrubs) in a stockpile for final reclamation purposes and sale during the 60% <br /> to 100% mining phases. The overburden excavated during Phase 1 will also be reserved, as <br /> needed, throughout the mining stages, to fill the pit, if mining ceases. See Figure 12, <br /> Exhibit D1 for a cross-section of the strata. <br /> 5.2.1 Site Development and Grading (Phase 1 [P1]) <br /> This section describes the earthmoving, impoundments, and size of the areas to be worked <br /> during Phase 1. <br /> 6.2.1.1 Mining Methods and Earthmoving <br /> No mining will occur during Phase 1. This phase of the project will include minor site grading <br /> and vegetation removal within the Permit Area on the Affected Lands and construction and <br /> topsoil and seeding application of the perimeter berm. The access road and driveway <br /> improvements will also be constructed during this phase, upon issuance of the new CDOT <br /> Access Permit. Specific activities include the following: <br /> • The topsoil and overburden (vary across the site, 1 - 7 feet of fine sediments) will be <br /> removed from the Affected Area (Figure 12, Exhibit D1 for a cross-section of the <br /> strata). The overburden will be used to construct a 5-foot-tall perimeter berm around <br /> the mine area, to control visual and noise impacts in accordance with Garfield <br /> County Land Use Code (LUC) standards, comply with the Garfield County Permit <br /> conditions, and the United States Fish and Wildlife Services' recommendations. The <br /> berm surface will be decompacted, surfaced with topsoil and upland seed mix as <br /> soon thereafter as practical based on seasonal conditions. The excess overburden <br /> (30,423 cubic yards [CY]) will be temporarily stored as mining progresses to provide <br /> fill in the instance mining ceases. This material will be sold as a secondary <br /> commodity, to allow for the expansion of mining during the 60% to the 100% mining <br /> stages during Phase 3. The excess topsoil (9,539 CY) will also be stored and <br /> stabilized with an upland seed mix (minus the shrubs). The topsoil (9,006 CY)will be <br /> sold as a secondary commodity during the 60%to 100% mining stages during Phase <br /> 3, to allow for mining expansion. Approximately 533 CY of the excess topsoil will be <br /> needed to reclaim the greenbelt areas during final reclamation during Phase 3 and <br /> Phase 4. Attachment C includes the typical cross-sections at the boring holes. The <br /> estimated areas and volumes of material excavated and used for the berm <br /> construction and revegetation during Phase 1 (P1) are provided in Table 2 and <br /> summarized below: <br /> • The average centroid to centroid haul and grading push distances for overburden <br /> and topsoil placement to construct the berms is 250 feet- 350 feet. <br /> 'United States Geological Survey.Geology map of the Silt quadrangle,Garfield County,Colorado.Miscellaneous Field <br /> Studies Map MF-2331.Reston,Va: U.S.Department of the Interior.2001 <br /> 22 <br />