1982-02-18_GENERAL DOCUMENTS - M1981302

Home Browse Search

Staff Recommendation Docket #SU-81-10 November 13, 1981 Page Six powered trucks and 12-18 dBA noisier than automobiles. Moving diesel truck noise in the area of a gravel pit also rises and falls in frequency and level , which tends to make it more noticeable than a stationary source with a fairly constant level such as a crusher. Because a main component of diesel truck noise is the exhaust stack, which is normally about 8 feet above ground level , truck noise is also difficult to attenuate with noise barriers. For these reasons, it is felt important to preserve the truck mix projected by the applicant in their transportation studies. This would mean that about 30% of total trucks would be unlikely to be diesel-powered. There have been suggestions to prohibit processing on site and/or prohibit trucks other than the applicants' trucks on the site. Eliminating proces- sing on site would require hauling greater volimes of raw pit run off of the site and might require hauling fill materials back to the site for reclamation. Limiting access to only the applicants' trucks would require hauling processed materials to another distribution point. In either case, the applicant would haul the materials in the most efficient manner possible, using the largest trucks available to minimize costs. Either or both of the suggested limitations would increase the percentage of large, noisy, slow-moving diesel trucks. From previous discussion of noise impacts of the plant site, it has been concluded that processing on the site can be made acceptable. The prevention of adverse impacts due to allowing trucks other than the applicants' on the site must be the responsibility of the applicant. All trucks on the site must conform to proper maintenance and operation standards. It should be noted that only the applicants' trucks will be operating in the pit areas , with other trucks being limited to the plant site/loading area. One obvious mitigation method for truck noise is to move haul roads as far as possible from residential areas. In the alternate mining plan, the applicants have proposed moving the north haul road to run approximately through the middle of the widest portion of the site. This would require relocating the haul road as the central area is mined. Staff's recom- mendation is to construct a permanent (life of the operation) paved haul road immediately inside the flood control dike which runs along the eastern boundary of the property. This location would be farthest removed from the residential areas and screened from the north and east Turnpike exposure by the dike and trees on the dike. The haul road area should be mined initially, resulting in a lowered elevation which would partially screen the haul road from residential areas and reduce noise and visual impacts. The worst case for hauling noise is once again the mobile home park adjacent to the Old Marshall Road (County Road #51) . Trucks from the pit would be required to make a left turn from the south haul road onto Marshall Road, proceed past the mobile home park to a point about 400 feet south of the park entrance, make a right turn, stop, and accelerate onto Highway 93. The center of Marshall Road is located approximately 80 feet west of the nearest mobile home.