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Memo to PCPC <br /> Re: SUP No. 1999-002 <br /> June 9, 1999 <br /> Page 12 <br /> sedimentation controls such as impounds, silt fencing, and diversion ditches, will <br /> be established to prevent soil erosion and siltation of streams. <br /> Mining of the Limestone and bottom sandstone will continue from this box cut in <br /> a southerly direction. Production panels will be established running from <br /> northwest to southeast along the formation strike (N49OW). The dimension of the <br /> weekly panels must be at least 24 feet wide by 600 feet long, using a 12' on <br /> center blasting pattern. It is anticipated that approximately 4,300 cubic yards of <br /> soil overburden along with 15,000 cubic yards of limestone will be removed in <br /> weekly panels. The yearly panel dimension will be approximately 300 feet wide <br /> by an average of 1800 feet long yielding about 1.5 million tons per year. The <br /> total area affected by mining in a given year will be about 12.5 acres. <br /> As the panels progress, topsoil will be removed from areas to be mined and <br /> deposited in areas that the limestone and sandstone have been removed from. <br /> This 12.5 acre annual quarry area allows that less than 30 total acres of land will <br /> be affected at any given time. <br /> Prior to drilling and blasting, a scraper will remove the soft organic surface soils <br /> and subsoils to a storage area adjacent to the panel for easy reapplication to the <br /> mined area. It is proposed that each 12.5 acre panel be fully reclaimed by <br /> replacing the subsoil and surface organic soils on the floor of the pit and <br /> reseeding with an approved seed mixtures. A roadway will remain open along <br /> the length of the box cut panels to allow vehicle access to the active areas <br /> during mining. <br /> With removal of the limestone, sandstone, and a 25% to 30% swell factor for the <br /> overburden, upon reclamation, the surface elevation in the quarry area will be <br /> lowered an average of 40 feet. <br /> Blasting Methods <br /> It is anticipated that blasting events will occur two to three times per month. A <br /> detailed geological investigation precedes each blasting event and allows for <br /> much tighter control over the blast pattern and charge, which mitigates ground <br /> vibration and atmospheric shock waves. Monitoring of ground movement and <br /> shock waves will ensure they are within guidelines issued by the US Bureau of <br /> Mines. <br />