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EXHIBIT D <br />Mining Plan <br />The basic mining operation method to be employed will involve reduction of the natural surface <br />elevation by open-pit mining extraction of crystalline rock within the mining boundary of the <br />PUD, less the required setbacks per the Colorado Department of Minerals and Geology (DMG) <br />rules. Reduction of the natural surface elevation will be accomplished by removing the <br />crystalline rock in benches (layers) that vary between 20 and 40 feet in height, generally <br />averaging 35 feet in height, until the ultimate lower level of the quarry is reached at the 6,200- <br />foot elevation. As each layer of rock is removed, highwalls and benches are created. All of the <br />highwall inter-bench vertical faces will be limited to maximum slopes of 80 degrees. Benches <br />with a minimum width of 35 feet will intersect the face of the highwall. These benches will be <br />spaced at an average of every 35 feet in elevation. <br />The open-pit mining operation will employ conventional mining equipment comprised of blast <br />hole drills, rubber-tired front-end loaders, off-highway mining trucks, a motor grader, and a <br />bulldozer. The normal mining cycle will involve drilling a series of blast holes, loading the blast <br />holes with explosives, blasting, loading the broken (blasted) material in the off-highway mining <br />trucks, delivering the material to the primary crusher for size reduction and then completing the <br />process of making the various products through a series of screens and secondary crushing units. <br />All of these operations are carried out in compliance with the applicable mining laws and <br />regulations. <br />The mining of the additional area will occur in a similar manner to present mining methods. For <br />instance, the mining will start below the ridgeline and proceed downward in a stair-step manner. <br />Each step or bench is approximately 35 feet high. The bottom of each bench is a horizontal <br />plane and the mining proceeds outward until all the rock is removed. Then a new 35-foot deep <br />cut is made and the excavation again proceeds outward. Therefore, the mining stair steps down <br />the slope until the quarry floor is reached. <br />RECEIVED <br />JUN 0 4 2003 <br />Division ~f Minerals and Geology <br />Specification Aggregn[es <br />DMC 1!2 Permit Amendment <br />-5- <br />