Laserfiche WebLink
�', � !%�i. <br />" SHAF�R, N�V�FSOTA <br />December23,2004 <br />Memo to: The File <br />From: Scott Spisak <br />Re: Pavement Recycle Crushing Noise Monitoring <br />On November30,2004, we engaged American Engineeringtesting, Inc. (A.E.T.) to <br />perform noise monitoring of Intex Corporation's crushing equipment that was recycling <br />pavement at our Johnson Pit at 12500 Rich Valley Blvd. In Rosemount. The monitoring <br />was performed on December 2,2004. <br />There were no other operations being conducted on the property that day. Intex <br />equipment included a CAT 988F wheel loader, a jaw type primary crusher, a cone type <br />secondary crusher with vibratory screens, a trailer enclosed diesel generator and several <br />belt conveyors to transfer material from the primary crusher, through the secondary <br />crusher and onto the stockpile. <br />The monitoring accounted for the "worst case", that being downwind from the secondary <br />crusher and generator with no obstructions or vegetation to mitigate the sound. <br />The test results (see report attached) indicate that under similar severe conditions we <br />would meet the MPCA Noise Classification Leve13 (Industrial & Manufacturing <br />Category) Daytime L10 and LSO requirements at a distance of250 feet fiom the- <br />operation. Using the MPCA's "A guide to Noise Control in Minnesota"for the same <br />conditions, we can estimate the decibel level at f�ther distances. The test results indicate <br />that the crushing equipment behaves like a point source where doubling a given distance <br />from the source results in a 6 decibel drop in noise levels. <br />Using this method, we would meet the MPCA Noise ClassificationLevel2 (Retail, <br />Business, Parks category) between a distance of 600 and 800 feet from the operation. We <br />would meet the MPCA Noise Classification Levell (residential) requirements between <br />10U0 and 1200 feet fram the operation. <br />Of course few if any sites would have 600 to 12QQ feet of clear, unimpeded sight line <br />distance in a downwind direction from this type of operation. Urban areas in particular, <br />would have obstructions such as buildings or stands of trees that would deflect, absorb or <br />M Equal Opportunity Employer <br />