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Memorandum to: Kent Peterson Bituminous Roadways October 7, 2010 Page 2 conditions with the asphalt silo and load -out drum in operation and with trucks on -site loading and hauling asphalt. The results of the noise monitoring from the two existing plants are presented in Table 1. Wenck recorded the noise levels ofa crushing operation during a previous noise monitoring study at a facility in New Brighton. The noise level generated by the crushing operation was 82 dBA at 50 feet (Table 1) while all crushing equipment was in operation. Table 1: Monitored noise data from existing plants Facility Noise Reading Monitored Noise Level (dBA) Inver Grove Heights 30 feet away Between Asphalt 71 2 Drum and Silo Shakopee 20 feet away Between Asphalt 79.4 Drum and Silo Crushing Operation 50 feet away from Crusher 82.0 The noise levels from the Shakopee plant were used in noise calculations to estimate the level of noise at the proposed project site to provide a conservative estimate of future noise levels created by the proposed Roseville plant. The monitored noise levels are considered "average" levels and are compared to the MPCA L50 noise limits. The noise levels at 250 ft intervals from the proposed location of the asphalt silo and Toad -out drum on the proposed project site are presented in Figure 1. The data displayed in Figure 1 supports the conclusions presented within the EAW that the proposed project will comply with MPCA noise standards at properties adjacent to the project site. Under normal operational conditions, the noise created by the proposed project would range from 39.4 to 57.7 dBA at properties within the industrial park (Figure 1). These values are less than the MPCA Daytime and Nighttime L50 noise standard which are both 75 dBA within industrial areas. The nearest residential receptors are located to the south of the proposed project site, approximately 1,500 feet from the proposed asphalt silo and load -out drum. Noise levels produced by the proposed project under normal operating conditions would range from 39.4 to 41.9 dBA within the residential neighborhood south of the project site (Figure I). This is less than the MPCA Daytime L50 residential noise standard of 60 dBA and also Tess than the Nighttime L50 noise standard of 50 dBA. The proposed project will also employ a temporary mobile crushing unit two times a year for up to a three week period each time. While the normal operations of the asphalt plant will be generally from 6:00 am to 8:00 pm and may include 24 -hour operations on some days if required by state highway projects, the operation of the crushing unit will be limited to daytime hours from 7:00 am and 7:00 pm. Wenck recorded the noise levels ofa crushing operation during a previous noise monitoring study at a facility in New Brighton. The noise level generated by the Tb125•Biiurmnous Ril 1 2009 Roseville CtJWoisetnxmo•2OIO.10.06 doe