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MMRR Quarry, M-2004-067 Response to Jan. 21 Adequacy Review March 23, 2005 Page 5 that the reclaimed pit floor elevation is achieved after all excess unusable material under the 10-year mining plan has been used as backfill. Realignment of the main access road requires an adjustment of the original estimate of waste rock generated in the start-up of the quarry. The new alignment will generate an additional 400,000 cubic yards of cut, more or less. By virtue of the site layout, this volume of material must be primarily hauled off-site prior to the opening of the access road, processing pad, waste rock pile, and other options for use on-site. Process Fines. As a percentage of quarry rock crushed on the site, the MMRR Quarry is anticipated to yield a typical volume of process fines. Because no sand or fine-grained fraction is anticipated to be significant portion of the pit run at the MMRR Quarry, the typical yield of fines may be less than 1 % of input by weight. For the purposes of Rule 6.4.4(f), the applicant will estimate a maximum volume based on a 3% fine yield by weight. Given reserves of at least 10 million tons under the mining plan, this results in a maximum tonnage of fines generated over the life of the proposed operation of 300,000 tons, or a volume of approximately 200,000 cubic yards. Fines will not be stockpiled for any significant amount of time and will not accumulate beyond the capacity of the processing area. Fines will either be used as a substrate in reclaimed areas (to a depth of 2 feet, see Exhibit E) or classified as unusable and backfilled in the pit floor as described above. Drainage Design. The technical response to this review comment is definitively provided by the memorandum of the project engineer. The revised plans for drainage include an initial diversion around the waste rock pile. This diversion will convey undisturbed area runoff around the waste rock pile and back into the ephemeral drainage downstream of the mining facilities. The diversion ditches will generally be excavated in rock and not subject to erosion. If the ditch is located in earthen substrate, riprap lining will be placed to prevent erosion. Best management practices (BMPs) will be used to minimze sediment production and capture eroded sediments near their source. Sediment ponds will be constructed to capture sediment that could be eroded from operations areas. In addition, porous rock check dams will be installed in the access road drainage ditches to assist in trapping eroded sediment. These measures will effectively minimize the risk of erosion from the site.