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PAGE TWO <br />March 24, 1992 <br />MS. JANET BINN <br />Berms, two feet wide and one foot high will be constructed around three sides of the drill pad to intercept <br />10-year, 24-hour runoff and direct it to a 10' x 8' x 4.5' deep catch basin. The adequacy of the catch <br />basin volume is shown by the following calculation: <br />Watershed area ............................................. 0.11 acres <br />Universal soil loss equation - 3 year volume ......................... 20 cubic ft. <br />SCS runoff for 10-year, 24-hour storm .............................315 cu. ft. <br />Total required volume ..........................................335 cu. ft. <br />Catch basin volume 10' x 8' x 4.5' .................................360 cu. ft. <br />Raise boring of the ventilation shaft will be preceded by drilling of a 8-3/4 inches diameter vertical hole. <br />This hole will be reamed to a diameter of 13-3/4 inches which will serve as a pilot hole for the raise <br />boring operation. A mud pit approximately 13' x 10' x 3' deep will be used for containing the cutting <br />during the drilling of 8-3/4" hole. Muck generated during the reaming of this hole and during the raise <br />boring operation will fall into the mine. It will be hauled by underground transportation equipment out to <br />the East Portal, and placed in the roof fall storage area located adjacent to the gravel storage bin. This <br />material will then be hauled by truck to the mine refuse area for disposal. The drilling and raise boring <br />task is expected to take about seven days. <br />As stated earlier, the access route and part of the drill pad will be reclaimed soon after the completion <br />of the ventilation shaft. When the mining operations cease, the ventilation shaft cover and the concrete <br />pad will be removed and disposed of. The ventilation shaft will be filled by subsoil material from the <br />existing subsoil stockpile (see map 77 of the permit). Approximately 461 cubic yards of material will be <br />required to fill the ventilation shaft. The drill pad will be graded approximately to the original ground level, <br />covered with topsoil and reseeded with approved seed mix for the east portal area. WFU has estimated <br />the total cost of reclamation as $14,308.00. The area disturbed for the proposed task is estimated to <br />be approximately 0.25 acres. <br />Page III-36A has been added to the permit document to include the drilling of the ventilation shaft. The <br />post-mining bond calculation page of the permit will be revised and submitted once CMLRD finds WFU's <br />bond calculation acceptable or if CMLRD comes up with a different number. Currently, WFU has an <br />excess of $106,513.00 bond with CMLRD. WFU requests that the performance bond required for this <br />minor revision be deducted from the available cushion. <br />