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EXHIBIT D <br />Mining Plan <br />General <br />The proposed Duckworth property permit boundary will encompass 56.5 acres; mining <br />activities are anticipated to disturb approximately 50 acres. An existing mining operation <br />lies immediately to the south of this property. Pastureland lies to the west, low-density <br />residences to the north and east. The property is located North of Wetd County Road 20 ''/z, <br />West of Weld County Road 7. <br />The deposit consists of alluvial sand and gravel overlain by topsoil and overburden. The <br />topsoil and overburden layer ranges in depth from 2 to 5 feet with an average thickness of <br />3.6 feet. The sand and gravel deposit varies in thickness from 13 to 18 feet; the average <br />thickness is 15 feet. The deposit is underlain by a sandy siltstone. The maximum depth of <br />excavation will be 25 feet. Overburden volumes have been calculated at 148,000 bank <br />cubic yards and will be used for reclamation. Resource deposit is estimated to be <br />1,500,000 tons. <br />The groundwater level lies 3 to 6 feet below natural ground level. The deposit is therefore <br />classified as a wet alluvial deposit. However, mining operations will be carried out <br />following dewatering. The sand and gravel is catalogued in the report Sand, Gravel, and <br />Quarry Resources, Colorado Front Range Counties (Colorado Geologic Survey, 1974). <br />Mining Method <br />Dry mining techniques will be used at Duckworth. Initially, a dewatering ditch will be <br />excavated around the perimeter of the active mining area. Groundwater recovered in the <br />dewatering ditch will be dischazged in accordance with Colorado/NPDES dischazge permit <br />regulations. <br />The deposit will be mined in two phases. Topsoil and overburden will be stripped with <br />scrapers or dozers and placed separately in temporary stockpiles within the mining azea <br />limits. <br />The aggregate will be mined using front-end loaders. Mined material will be loaded on a <br />conveyor system for transport to Cottonwood, an existing DMG permitted site (M-1988- <br />042} located immediately south, for processing with a portabie screen and crusher. <br />Additional conveyors maybe constructed inside the mine areas to facilitate transport of the <br />resource. The mining face will be nearly vertical to % : 1 slope. Direction of mining will <br />be from the east to the west, and will progress down to the siltstone bedrock. <br />Access and haulage roads required for the proposed operations aze already in existence. <br />We are not proposing to haul any material from the site. <br />Duckworth Pit <br />OMG 111 Permit <br />Poge 7 of 45 <br />