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D.3.1. Noise Impact 4.5.1 Noise generated by mining equipment and excavation activities would result in an increase in the ambient noise levels at the nearest residence(s). (Draft EIR, p. 4.5-12.) Significance Before Mitigation: Significant Facts: Mining equipment and excavation activities would result in an increase in the ambient noise levels at the nearest residence(s). See Draft EIR,pp. 4.5-12 to 4.5-17. Mitigation Measures: Mitigation Measure 4.5.1 a: At the start of stripping operations for each phase, the applicant shall construct an earthen berm along the portions of the project site that face sensitive receptors located within 2,000 feet of mining operations for that phase. This includes residencesR4 and R5 northeast of Phase IV (this earthen berm would also attenuate noise to residences R5,R6, and R7) and residences Rl, R2, and R3,west of Phase III and southwest of Phase V. The sound barriers must be at sufficient height(approximately 10 feet) to block the line of sight to the nearest sensitive receptor. If continuous earthen berms of adequate size are already in place, additional berms would not needed. (Draft EIR,p. 4.5-16.) Mitigation Measure 4.5.1b: The Applicant shall conduct additional noise measurements after the completion of initial stripping activities to evaluate the effectiveness of Mitigation Measure 4.5.1 a in reducing resultant sound levels at outdoor activity areas of nearby sensitive receptors. For those residences requiring additional sound reduction, the Applicant shall fund the construction of solid walls (masonry walls or other similar construction) along those property lines of the residences, existing at the time'ofproject approval, facing the project site, if desired and allowed by the subject property owners. (Draft EIR, p. 4.5-16.) Mitigation Measure 4.5.1 c: For any residences that would exceed an interior noise level of 45 dBA, Leq indoors, the applicant shall upgrade house noise reduction via window and door upgrades on the side of the houses facing the mine, if the landowner desires and allows the work to be done. (Draft EIR,p. 4.5-16.) Mitigation Measure 4.5.1d: Nighttime mining shall be prohibited within 1,000 feet of residences unless noise measurements confirm that noise levels are below 45 dBA, Leq at the outdoor activity areas of adjacent residences. (Draft EIR, p. 4.5-12.) Findings: Implementation of Mitigation Measures 4.5.1a-4.5.Id would help to reduce noise levels, at nearby residences, due to noise generated by mining equipment and excavation activities. The earthen berms constructed pursuant to Mitigation Measure 4.5.1 a could reduce noise levels up to 10 dBA. The resulting maximum exterior noise levels are estimated to be 69 dBA Leq (79- 10) at Residences R4 and R5 immediately to the northeast. The resulting, maximum exterior noise levels are estimated to be 52 dBA Leq (62- 10) at residences R6, R7, and R8 farther to the 32