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6.4.4 Exhibit D <br />Mining Plan <br />The Stonewall #1 target gravel deposit lies within the Tecolote soil series <br />(Exhibit C -2) that comprises the entire proposed site. The primary commodity is <br />gravel to produce construction material. The Soil Conservation Survey Tecolote soil <br />series description indicates the very cobbly reserve lies within one inch or less of <br />ground surface. The proposed site is an abandoned air strip (Exhibit C -1) with some <br />range grass growth between surface cobbles and occasional Ponderosa pines (Exhibit <br />C -3). The target deposit is limited to 15 acres. The Soil Conservation Survey <br />indicates the target cobble is more than 80 inches deep, the extent of the survey. <br />Because Division of Water Resources data (Exhibit C -4) indicates depth to <br />groundwater is approximately 30 feet, mining is proposed to a depth of 30 feet or <br />two feet above groundwater whichever is deeper. This will be a dry mining operation <br />and mining methods will be consistent throughout the life of the mine. <br />The mine will be developed in three five -acre (Exhibit C -5) phases beginning <br />Phase 1 at the north end of the site, immediately south of County Road 13.3. Active <br />mining will be limited to one five -acre phase. Each consecutive phase will be <br />developed after reclamation of the previous section. The estimated life of mine is 15 <br />years depending on market demand. <br />Normal hours of operation are proposed from 6 am to 7 pm, five days per <br />week during the summer construction season. Operating hours may extend to <br />Saturdays if a government project or emergency demands. During winter months, <br />hours will be reduced to 7 am to 5 pm, five days per week. <br />Activities at the proposed site will include extraction with front end loaders, <br />screening, crushing, stockpiling and reclamation. If market demands, a portable <br />asphalt and /or concrete plant may operate from the site. Conveyors will transport <br />raw material from the working face to the processing area that will be located at the <br />south end of each phase inside the pit once the pit is developed. During initial mine <br />development, the processing plant will be located on natural ground surface adjacent <br />to the developing pit. <br />The top 18 inches of material will be stockpiled for use during reclamation. <br />Any and all topsoil encountered during mining will remain on site for use in <br />reclamation. Naturals and fines will be stockpiled or immediately used to <br />reconstruct perimeter slopes. In the event naturals and /or fines stockpiles are <br />projected to exist for more than one year, they will be seeded with fast growing <br />grass seed mix. <br />Stormwater berms will be either straw bales, waddles or constructed of <br />overburden as required by Colorado Department of Public Health and Environment's <br />Water Quality Control Division. All diversionary structures will be temporary and will <br />be removed during reclamation. Stormwater in the excavation will percolate within <br />72 hours. <br />Page 4 of 21 <br />