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San Joaquin County Community Environmental Setting,Impacts,and Mitigation Measures <br /> Development Department Noise _ <br /> Table 3.J-6. Mining Equipment Reference Noise Levels <br /> Type of Equipment Maximum Level,dBA at 50 feet Usage Factor' _ <br /> Scrapers' 89 40% <br /> Bulldozers' 85 40% <br /> Heavy Trucks' 88 40% <br /> Excavator' 85 40% <br /> Pump. 76 50% <br /> Loader 85 40% — <br /> Grader' 85 40% <br /> Dredge(for Wet Pit Operations)` 84 50% <br /> Asphalt Concrete and Rock Processing Plant° 84 100% <br /> Batch Plant' 84 100% <br /> Recycling Plant` 84 100% _ <br /> Back-up alarm 85' 20% <br /> Sources: <br /> ' Federal Transit Administration 1995. <br /> b Thalheimer 2000. <br /> ` Geier&Geier Consulting 1997. <br /> d Brown-Buntin 2003. — <br /> ` Estimate based on noise source information from Brown-Buntin 2003. <br /> e Society of Automotive Engineers 2003. <br /> Sound levels at prediction locations attributable to noise from mining equipment <br /> and aggregate processing(stationary sources)are summarized in Tables 3.J-7, <br /> 3.J-8, and 3.J-9. Sound level contributions of the plant and mining pit operations <br /> are shown individually,and as a cumulative noise level for simultaneous plant <br /> and pit operations. As the tables indicate,noise from aggregate plant operations <br /> is the primary cause of high sound levels at receiver locations. If the plant noise — <br /> did not contribute, the noise levels from the pits only would apply(e.g.,the <br /> columns for North Pit Stage I,II, or III only). The sound levels shown in the <br /> tables correspond to different stages of mining operations;Tables 3.J-7,3.J-8, — <br /> and 3.J-9 contain noise levels associated with North Pit Stages I,II,and III, <br /> respectively. For each stage, noise levels were predicted for two scenarios: <br /> equipment operating at existing ground level (breaking ground), and equipment <br /> operating 30 feet below existing ground level. Equipment noise in the mining — <br /> pits would decrease over time during excavation, as pit depth increases. Sound <br /> levels were assumed to be the same for both dry-pit and wet-pit operations under <br /> the assumption that noise levels generated by draglines and dredging would be — <br /> similar. The sound levels are shown in terms of Hourly Leg,for comparison to <br /> the County's noise ordinance standards for stationary sources. <br /> DeSilve Gates Quarry Project — <br /> Draft Environmental Impact Report 3.J-12 <br /> AS 05105.05 <br />