1982-02-18_GENERAL DOCUMENTS - M1981302

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Staff Recommendation • Docket #SU-81-10 November 13, 1981 Page Nine of daytime working hour ambient levels in the residential areas when no mining operations are in progress compared to noise levels under operating conditions. This continuous monitoring of ambient levels vs. operating levels is felt to be the fairest method to both the applicant and the residents. If ambient levels decrease, the standard for mining noise will decrease. If ambient levels from other sources in the area increase over the years, the mining noise levels would be allowed to increase propor- tionately according to the previously discussed standard of mining levels not exceeding 5dBA above ambient levels. Monitoring frequency and duration should be approached from a common sense standpoint. For in- stance, if the plant site is fully established and monitoring shows that standards are not exceeded at maximum operating levels, less emphasis can be placed on monitoring of the plant site. Monitoring in certain locations, such as the mobile home park when mining begins in the southern stage, will be critical as maximum mining activities shift from one part of the site to another. Monitoring of noise levels which divides noise levels into L LID, L 0, L and L on the "A" scale requires fairly sophisti�� 2d 10 euipm�Rt. Mi�i��Gm requirements for equipment would be an EPA-approved Type II sound level meter and accessories, which is not currently available to the County Health Dept. and is quoted in a 1979 publication as having a cost of about $750. With this minimum amount of equipment, adequate EPA-approved monitoring could be done, but the monitoring would be very time-intensive for Health Dept. personnel . Adequate monitoring techniques would require a minimum of one hour at each monitoring site, with two visits to each site (ambient levels and mining levels) required to obtain one complete set of data. Calculations to arrive at L L L and L levels can be done on an electronic calculator, buTafnis 1wgu1d50 aoipo require a good deal of staff time. Acoustics consultants will generally have Type II meters and some con- sultants have other equipment such as special magnetic tape recorders, multi-filtered octave band equalizers and mini-computers for more sophisticated noise analysis methodologies. The conclusion is that unless the Health Dept. could make arrangements for the equipment and staff time, the monitoring program would have to be conducted by a consultant retained by the applicant. The Health Dept. could be utilized for less sophisticated spot checks and monitoring in response to complaints. The details of the monitoring program can be worked out between the applicant and the Planning and Health Dept. staffs so that the program can be tailored to achieve the results discussed previously. Traffic North Haul Road Based on input from the applicants and their consultants, the City Transportation Dept. and County Public Works, the following conclusions have been reached by staff: