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<br />OVERBURDEN REMOVAL <br />• After the topsoil material is removed and stored or replaced, the overburden above the <br />gravel deposit is removed by scrapers or other suitable equipment. The overburden <br />consists mainly of clay with sandy clay and some brown shales mixed in. The thickness <br />of the overburden ranges from approximately 3 feet to 14 feet. The underburden consists <br />mainly of gray and brown shale and will not be disturbed by mining. See Exhibit D-1 for <br />thicknesses. The overburden material is removed and either backfilled in mined-out <br />areas or stockpiled in locations shown on Exhibit D-1, Mining Plan. <br />It is estimated that approximately 26,000 cubic yards (average) or overburden will be <br />removed each year. SCC may vary slightly from this schedule, depending on the quality <br />of the gravel. If, once the gravel is uncovered, it is found that the deposit contains more <br />fines than anticipated, the marginal gravel will have to be supplemented with better <br />material. This will increase the disturbed area, the overall gravel tonnage removed, and <br />corresponding soil and overburden volumes during the given period. <br />• GRAVEL REMOVAL <br />After overburden material is removed, operations proceed with removal of the gravel <br />material. The gravel reserves, ranging in thickness from 7 to greater than 20 feet, are <br />removed primarily with awheel-loader, supplemented as necessary with other excavation <br />and haulage equipment. The gravel is either loaded directly into haul trucks or fed to a <br />portable crushing/screening plant which processes the gravel and places it in temporary <br />on-site stockpiles for future use. The primary use for the gravel is as base and surfacing <br />material on SCC's roads and facilities in active operating areas. <br /> <br />D-4 Revised May 1998 <br />