5.5. PCSR 02-13-2007 - Laserfiche WebLink

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Tiller Corporation Elk River and Livonia Quarries Noise Assessment . 1.0 INTRODUCTION 1.1. Objectives of this Report This report evaluates existing and future sound levels associated with the mining and processing of sand and gravel at two locations in Sherburne County, Minnesota. One mine ("Livonia Mining Operation" is located in Livonia Township approximately six miles north of Elk River, Minnesota, on the west side of TH 169. The other mine, which is approximately three miles south of the Livonia Mining Operation has two active mining areas. The "Elk River Mining Operation" is located immediately west ofTH 169 and south of the new County Road 33. The "Elk River Washplant Facility" is located west of the Elk River Mining Operation and just east of the Sherburne County recreational trail. This report has two primary objectives: (1) To determine if the existing operations can continue into the nighttime hours as defined in the Minnesota noise standards (10 pm to 7 am) without exceeding the nighttime noise standards at the nearest homes. The L50, or level exceeded 50% of the time (median sound level) is the appropriate metric against which to compare the highest noise levels, which are associated with crushing and screening equipment. (2) To estimate the noise levels from future operations which mining activity is in its closest proximity to adjacent homes. . 1.2. Minnesota Noise Standards Noise impacts are evaluated here relative to the Minnesota noise standards for residential land uses, which are presented below in Table 1.1. It is assumed here that both mobile and stationary equipment may operate in one location for at least 30 minutes of an hour, so that daytime L50 standard of 60 dBA is the limit above which exceedances of the standards will occur. This is the most stringent applicable standard. Table 1.1 Minnesota Noise Standards for Residential Land Uses LIO L50 I Daytime (7:00 am to 10:00 urn) 65 dBA 60 dBA Nighttime 00:00 pm to 7:00 am) 55 dBA 50 dBA L1 0 is that level exceeded 10% or 6 minutes of an hour. L50 is that level exceeded 50% or 30 minutes of an hour 1.3. Organization of this Report Section 2.0 of the report presents assumptions used in this assessment including mine locations and mining activity. Section 3.0 of the report describes noise monitoring that was undertaken on Wednesday, 25 October 2006, before normal mining operations ceased for the calendar year. . Section 4.0 presents estimates of noise levels from future mining activity. Potential impacts and mitigation of noise is also discussed. Section 5.0 summarizes the fmdings and recommendations of the study. David Braslau Associates, Inc. Page 1