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6.4.4 EXHIBIT D -Mining Plan This is a new application for a gravel mining operation located in Garfield County. The disturbance created by this mining operation will not require the diversion or impoundment of water. Water used in the mining operation will be for occasional watering of the access roadway, in which case the water will be imported and spread by truck. There is no evidence of ground water in the gravel deposit. However, if ground water is encountered, pit floor projections will be revised to maintain a minimum of 2 feet of undisturbed material above the groundwater. The affected area is illustrated on Exhibit C-1 Pre-Mining Topography. The location of existing features, immediately adjacent structures and other pertinent information are also portrayed on this map. The life of the mine, based on the present demand for materials, is estimated to be about 2 years based on a production rate of 100,000 tons per year; the actual rate of mining will depend on the changing demand for construction materials. Mining will begin in summer or fall of 2005. The material to be mined is weathered sandstone and shale located along the ridge top. Typically, this stratum is weathered up to 20-feet deep. Underlying this weathered strata are hard layers of sandstone and shale. The only commodity to be mined is the weathered sandstone and shale. This material will be used for unclassified fill material, used to plate roadways, drill pads, parking lots and industrial sites. Mining will begin at the northernmost end of the disturbance area and will continue to the southern edge of the permit boundary. The site will be mined to a depth of about 20- feet. Mining will generally create a flat and gently sloping surface with no steeper than 3H:1 V slopes on any edge of the pit. A berm will be maintained around the affected area to contain runoff of stormwater from precipitation events and snowmelt. There are few if any noxious weeds throughout the projected disturbance area. Noxious weeds on the permit area will be controlled as per the prevention plan included in Exhibit J -Vegetation. Available topsoil will be stripped from the area to be disturbed and stockpiled along the west edge of the pit. As a stabilization measure, any topsoil which is to be stockpiled longer than about one growing season will be broadcast seeded with a perennial sod- forming grass cover such as western wheatgrass at a typical rate of 20 pounds/acre. Excavation of the gravel pit will create advancing side slopes. Side slopes will typically be mined no steeper than 3h:1 v slope so no slope flattening will be required before topsoil is applied and graded to depth. The advancing face of the pit will also be mined no steeper than 3h:1 v.