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<br />equipped with similar control devices. The crusher has spray <br />bars to add additional moisture to the pit run when needed. <br />Noise <br />Colorado state law (Senate Bill 197, 1971) limits the allowable <br />daytime noise level for industrial sites to 80 dB (A) with <br />peaks of 85 dB(A) allowed for 15 minutes of any 60 minute time <br />period. Noise levels are to be measured 25 feet outside the pro- <br />perty line, not at the noise source. When the crusher, the loudest <br />noise source, is located 100 feet inside the property line <br />(zoning requires a 75 foot minimum), the sound pressure level is <br />43.4 dB(A), or less than the 45 dB (A) typical in the average <br />residence with minimum street noise. For comparison, 58 dB (A) <br />is considered typical of the average office. <br />Plant noise will be mitigated in three ways: <br />1) Stockpiles will buffer the crusher noise <br />2) The crusher will be located about 700 feet inside the <br />property ].i.nes, well beyond the distattce needed to meet <br />state law requirements. <br />3) The wind, which carries sound, is primarily from the <br />west and will carry noise toward the mining operations <br />east of the plant, not toward residences or passers-by. <br />Water <br />Site preparation for the concrete plant will include placement <br />of 3 feet of compacted sand and gravel for a base. A 3 foot berm <br />D-11 <br />