Item 6: Ordinance on Delta Sand and Gravel

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4. Noise Impacts on Existing Residences The primary source of noise impacts to nearby residences from the mining operation is where heavy equipment digs and breaks rock, loads the rock onto trucks, and transports the rock offsite or to the existing processing facility, where the material is crushed and sorted. The processing facility will not move, so it will cause no increase in noise above current conditions. Therefore, potential increases in noise will be from the extraction and transportation processes, and in the construction of the aquaclude, which is a specialized form of excavation possibly exempt from DEQ regulations as discussed above. There are two phases in the extraction process: first, the top layers of soil and the “first lift” of rocky material (8-10 feet deep) are removed, and second, a series of “second lift” extractions each about 16-18 feet deep. The difference is important because during the second lifts, the equipment will be operating below grade level. The quarry wall itself will act as a noise buffer between the equipment and the nearest surrounding properties and conflicting uses. Regarding transportation of the quarried materials, there are several gates that provide access to/from the site. The direction of travel depends on the materials being transported (e.g., are they first processed?) and the direction of the receiving site. The primary access point is on Division Avenue, near the processing facility. No new gates are proposed, nor are there changes proposed that would inherently affect the use of the existing gates. Therefore staff finds that there is no change proposed in the amount of noise due to the transportation of extracted materials. Daly-Standlee and Associates (DSA), engineers acting on behalf of the applicant, prepared a noise study (Exhibit 1F) and responded to comments during the public hearing. DSA used the more stringent Oregon Department of Environmental Quality (DEQ) Noise Regulations for Industry and Commerce that apply to a “new noise source” on a “previously unused site,” not the more lenient noise limits for “existing noise sources” that could apply to mining expansion sites. The DSA noise study provides recommended mitigations for four zones within the expansion site. The zones are based on proximity of the excavation activities to sensitive receptors off site, such as residences. DSA concluded (after several revisions responding to public testimony) that, with appropriate noise mitigation measures, noise generated by future mining operations in the proposed expansion area will comply with the most demanding interpretation of the DEQ at all residential properties surrounding the proposed expansion area. There is evidence from two peer reviews that the mining operations, with mitigations, could meet DEQ standards. Both Planning Commissions agreed that the noise conflict could be minimized to a level that meets the DEQ standard. The Eugene Planning Commission vote was 3-2 and the Lane County Planning Commission vote was 3-2, with 1 abstention. Most opposing testimony came from Arthur M. Noxon, PE, acoustic engineer. In staff’s view, the more substantive comments pertain to the following issues: 1. Ambient noise levels in residential areas were not measured from the more sheltered, quieter private outdoor spaces that may be most impacted by the expanded quarry. 2. Impulse noises, such as the banging of dump trucks as they unload, were not measured in the DSA study. The aquaclude will involve filling of the trench proximate to residences, presumably with associated impulse noises, inside the DEQ setback for mining operations.