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02/05/98 TBl! 16:05 ~~ 6124825232 R\MSEY CO PUBLIC WORKS ~002 . Memorandum To: Dan Soler Bob Paine T my Noonan From: Curtis Pratt SUbject: Sound Level Measurement of Concrete Recycling at Danner, Inc. Gtavel Pit in South Saint Paul Date: February 4, 1998 Sound li:vel measurements were made of the concrete recycling operation at the Danner, Inc. gravel pit in South Saint Paul on February 2, 1998. Equipment in operation during the sound level measurements included a Cedarapids jaw crusher, a Cedarapids impact crusher with screen, a Caterpillar gencrutot, conveyor belts, a front end loader, and a backhoe operating a jackhammer. Sound levels were recorded at a numb!;:T of locations and distantes from the operation. Because there Were a number of other major sound sources in the area, it was not possible to take accurate sound level measurements at greater distances than 260 feet from the operation. Sound levels were measured using a Quest Electronics M-27 Noise Logging Dosimeter, which meets ANSI 8I.4.1983 Type n specjfication~. as required by the MPCA. The MPCA rules are written in terms of Ll 0 and 1.50 ~oUT\d levels. The L- EQ closely approximates the L50 under steady sound levels such as rock crusher or concrete recycling operation. Summari~ed in Table I, below, are the sound level measurements recorded on February 2, 1998 of the concrete recycling operation at the Danner, Inc. gravel pit. TABLEl Sound recording Location Distance (ft.) L-EQ Sound Level in dB(A) West Side 50 84-2 East Side 90 79.7 South Side 130 76.5 North Side 210 75.0 South Side 260 69.9 From tl1e above sound level measurements made at the Danner, Inc. gravel pit. projected sound levels were calculated for the closest residential receptors to the proposed location of the concrete recycling opera.tion at the Ramsey County Kent Street Site. These projected sound levels are tabuJated in Table 2, below, The receptors are, (A) 497