2008-04-15_REVISION - M1980244 (336)

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d e d- 5. Site E-E Receptor E' is 1972 ft. from the mine boundary. Receptor E-E line-of-sight is close to the surface starting at 1400 ft. from the mine boundary and ending at the receptor, which is at 1972 ft. This analysis assumes that there will be no reduction in noise associated with the surface effect along this portion of the direct line-of-sight. The approximate 30 ft. high berm will provide a minimum noise reduction of 10 dB(A) and the distances to the 55 dB(A) and 50 dB(A) contours are shown on Figure E-E. 6. Site F-F Receptor F' is 1245 ft. from the mine boundary. Receptor F-F line-of-sight is unobstructed. A 10 dB(A) reduction will be provided by the approximate 30 ft. high berm. The distances to the 55 dB(A) and 50 dB(A) contours are shown on Figure F-F. 7. Site G-G Site G' is 1777 ft. from the mine boundary. There will bean approximate 30 ft. high berm at the mine boundary, which will provide a minimum noise reduction of 8 dB(A) and both the 55 dB(A) 50 dB(A) contours are shown in Figure G-G. 8. Site H-H Site H' is 2787 ft. from the mine boundary. There is a slight rise in the terrain at about 1800 ft. from the mine boundary. The vertical obstruction to the line-of-sight by the rise in terrain is about 40 ft. and it will provide 6 dB(A) of noise reduction. The 55 dB(A) noise location for the mining equipment extends to the top of the rise in terrain (see Figure H-H). The 50 dB(A) location for the mining equipment is located just beyond the rise. C. OTHER CONSIDERATIONS 1. Growth Medium Salvage Growth medium salvage will take place only during the daytime hours and the noise level limit under these conditions is 55 dB(A) at the closest inhabited structure. A listing of the equipment anticipated to be used during this phase is presented in Table 4. Table 4 Mine Development Equipment and Noise Emission Levels Category Manufacturer Description dB(A) @ 100 ft. Dozer CAT D-10N 76 Haul Truck CAT 777 74 Loader CAT 992 75 One or two CAT D-10 dozers will be used for clearing, grubbing, stripping and piling growth medium into short-term stockpiles. The short-term stockpiles will be within the MLE boundary and the work will only be done during the daytime because the equipment operators need to have a clear view of the surface material. The 55 dB(A) noise level distance for one CAT D-10 dozer is 1122 ft. and when the dozer is pointed in the direction of maximum noise. The dozer may leave the site after the preparation of the temporary stockpiles is completed. Material to be moved to another location will be loaded on a CAT 777 haul truck by a CAT 992 end- loader. Either the loader or the truck will be at maximum noise emission but not both at the same time or at the same location. Under these conditions, the 55 dB(A) contour from each will extend for a distance of 1000 ft. When both the CAT 992 loader and the CAT 777 haul truck are next to each other and operating at maximum power, the combined 55 dB(A) noise footprint or contour distance will be 1400 ft. Work at Site A-A will take place only during the daytime. All of the other sites are more than 1400 ft. from where growth medium salvage will take place. Rev # EDI Job No. C3616 Page 13 of 17 3925 S. Kalamath St., Englewood, Colorado 80110 • voice: 303-761-4367 9 fax: 303-761-4379