5.5. PCSR 02-13-2007 - Laserfiche WebLink

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Tiller Corporation Elk River and Livonia Quarries Noise Assessment . 4.4. Elk River Wash Plant Facility The existing locations of the shale jig and wash plant are shown in Figure 4.3. These will remain the same in 2007 and the future, but, as shown in the figure, will be complemented in 2007 and the future with the relocated cone crusher and screens from the Elk River Mining Operation. An earth berm to replace the stockpiles will be located along the western perimeter of the wash plant and processing area. The berm was initially analyzed with a height of 12 feet above grade but was modified as discussed below to keep the noise at the homes to the west below the L50 50 dBA nighttime standard. As seen from the figure, grade increases generally from the south to a high point of 1001 feet before dropping again to the north. Pre L50 levels by source and the overall L50 level at the nearest homes in 2007 and beyond are shown in Table 4.3. Levels with an opening in the berrh are shown to demonstrate the importance of shielding the adjacent homes from process equipment noise. Table 4.3 Elk River Wash Plant Sound Levels (L50 in dBA) . Wash Plant - 12 Foot Berm (with open l!ap for vehicle access) Homel 54.7 Home2 57.5 Home3 48.4 Home4 49.6 Jig 53.9 Cone 54.8 Jig 45.2 Jig 46.4 Cone 44.5 Loader 52.8 Cone 42.6 Cone 43.8 Loader 43.8 Jig 48.6 Loader 42.5 Loader 43.5 Wash Plant - 12 Foot Berm (without open l!a):) Homel 49.8 Home2 51.8 Home3 48.4 Home4 49.6 Jig 46.5 Jig 48.6 Jig 45.2 Jig 46.4 Cone 44.4 Cone 46.4 Cone 42.6 Cone 43.8 Loader 43.8 Loader 45.6 Loader 42.5 Loader 43.5 Wash Plant - 12 Foot Berm with 21 foot center section and no open l!ap Homel 48.1 Home2 49.9 Home3 46.7 Home4 49.0 Jig 44.7 Jig 46.6 Jig 43.4 Jig 45.8 Cone 42.5 Cone 44.2 Cone 41.1 Cone 43.1 Loader 42.4 Loader 44.1 Loader 40.8 Loader 43.0 A continuous 12-foot berm will not be sufficient to bring the L50 at Home2 (with the highest elevation) down to 50 dBA. The analysis suggests that constructing a berm with a 21-foot center section will be needed. Even with an opening in the l2-foot berm, however, sound levels will comply with the L50 60 dBA daytime noise standard. Unless homes are constructed south of Home 1, it may be possible to stop the berm approximately 200 feet from the south property line to provide for vehicle access to the west of the berm. Otherwise, a gap can be provided in the berm provided that the gap is shielded on both sides to prevent a direct noise path through the opening. . y: \jobs\2006jobs\2061 02\report\tiller _quarries_noise _ assessment.doc David Braslau Associates, Inc. Page 17