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<br />,S <br />,~~ <br /> <br />' EXHIBIT D -MINING PLAN <br />Alternative Reclamation Plan <br />SI-B AGRA Project E92-7075 <br />Page 3 <br />Four horizons have been targeted for mining at Dowe Flats based principally on their calcium <br />carbonate content and utilization potential at Southdown's nearby cement plant. The west limb <br />of a southward plunging syncline contains the four beds of interest; all outcrop along a general <br />north/south strike and exhibit gentle dips to the east. The Western most seam (also the <br />stratigraphically lowest) has been somewhat resistant to erosion and is referred to as the Hi-Cal <br />I ridge. Expressions of the other horizons are more subdued and these are known locally as simply <br />the 2nd, 3rd, and 4th ridges (Map E shows the areal extent of mining for the four ridges with the <br />overlaps due to the stratigraphic superposition of the limestone beds). <br />' A primary objective of the mining plan has been to achieve a 25-year project life, given the <br />expected product mix deriving from the four minable seams and the overall annual tonnage that <br />must be delivered to the cement plant. Currently this annual figure is 760,000 tons, with roughly <br />' 40% to 45% of this amount contributed each by the Hi-Cal and 3rd ridges. Because the Hi-Cal <br />ridge, at its outcrop, dips more steeply than the others, the desire is to maximize mining along <br />its strike length and to avoid excessive down-dip extraction; the objective is to minimize waste <br />' handling associated with the removal of the limestone beds. As a result of these factors, it has <br />been determined that the Hi-Cal bed will need to be mined over a strike length of almost 8,000 <br />' feet and that the 2nd and 3rd seams will be extracted over a linear distance of 5,000 feet. Only <br />1,900 feet of the 4th ridge outcrop will be disturbed. <br />' Mining of each of the respective beds is planned to begin at a southern point along the outcrop, <br />with the pit faces advancing toward the north. Since the limestone wilt be transported to the <br />south for delivery to the plant, the southerly starting location should serve to minimize haulage <br />costs during the early years of operation. <br />' Entry into each of the four pits will be from the west; in-pit and mine haulroads are planned with <br />a surface width of 60 feet in order to allow safe two-way traffic, and grades will be held to a <br />' maximum of 8%. This latter figure will be significant only on the Hi-Cal ridge wherein the <br />outcrop dip attains an inclination of nearly 13%. <br />' Mine development will be essentially a box cut operation whereby overburden removed during <br />a given point in mining is placed to backfill a previously mined portion of the mine. As discussed <br />AGRA <br />' Eerth & Environmental Group <br />