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• Mined Land Reclama n Division <br />Department of Natu~ Resources • <br />Mr. Peter V. O'Connor <br />June 11, 1985 Page 3 <br />The attached photocopy made from the DuPont Blaster's Handbook shows <br />the peak particle velocity 2.0 inches per second as safe blasting <br />criteria for residential structures recommended by the U. S. Bureau <br />of Mines. <br />The formula to find peak particle velocity is: <br />Scaled Distance = Distance to Structure <br />Pounds of Powder/Delay <br />The attached photocopy of DuPont's typical borehole densities .of <br />Anfo shows pounds per foot. <br />Assume: 15 holes per row, 20 feet deep, 3 inches in diameter. <br />Therefore: 15 X 20 X 2.60 = 780 pounds per delay. <br />The nearest structure to the quarry is 1300 feet. <br />Scaled Distance = 1300 .46.5 <br />780 <br />Going to the graph, you find the scaled distance 46.5, then follow <br />that line upward to Upper Limit Normal Confinement, and you arrive <br />at an approximate 0.80 peak particle velocity which is far lower <br />than the 2.0 recommended by the U. S. Bureau of Mines. Fly rock <br />may travel 100 to 150 feet. <br />There are no other structures, other than the fish hatchery,within <br />one-half mile. <br />The permit boundary will be posted. <br />The upgraded existing roadway is shown on Exhibit C. <br />Exhibit E - Reclamation Plan, Paragraph 1, Pale 3 <br />The BLM has agreed to the final land use as Wildlife habitat. <br />Paragraph 2, Page 3 <br />The channel on the easterly side and southerly side of the permit <br />area will not be interrupted during reclamation. Sde will stop our <br />mining short of these draws so as to not change the natural drainage <br />of the entire area. Exhibit F reclamation map has been revised. <br />