2012-10-04_REVISION - M1995030 - Laserfiche WebLink

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Mr. Gebhart Page 12 October 4, 2012 6.4.3 Exhibit C — Pre - mining and Mining Plan Map(s) of Affected Lands No comment. 6.4.4 Exhibit D — Mining Plan 2. The applicant has stated that the dredge is capable of mining to depths of 60 ft. Exhibit C -1 shows the reclaimed lake in Stage I will be 50 ft. deep. Please clarify if the gravel deposit will be mined to a depth of 60ft. and then backfilled to a depth of 50ft. or if the gravel deposit will only be mined to a depth of 50ft. 3. The applicant has stated that mining with a dredge results in pit walls with a natural angle of repose of 2.5H:1V. The applicant also states that the mining method will result in an overhang which will need to be removed using explosives. Please clarify this discrepancy. 4. The applicant has stated the mining line will be set 75 ft. inside of the 25 ft. mining setback, for a total offset of 100 ft. from the permit boundary. If the gravel deposit is mined to a depth of 60 ft. and sloughing will occur resulting in an angle of repose 2.5H:1 V, then there is the potential the top bank of the mine face could extend 150 ft. from the mining line. Please clarify how the proposed offset of 75 ft. will allow the Operator to maintain the 25 ft. setback from the permit boundary. 5. The Mining Plan states that at any given time no more than 5 acres will need to be revegetated. The Reclamation Plan states that the plant site will be resoiled and revegetated if it does not remain following the completion of reclamation. Until such time as the Operator receives approval to locate an asphalt /concrete batch plant on the site, the total area requiring revegetation must include the 7.22 acre plant site. Please revise Page 9 of the application accordingly. 6. The applicant has identified rangeland as the post- mining land use. In addition, the applicant has stated an asphalt/concrete batch plant may be located on the site and may remain after reclamation is complete. In order for the asphalt/concrete batch plant to remain on site the approved post- mining land use(s) must include industrial /commercial. The applicant may designate industrial /commercial as a post- mining land use during the review of this application. Otherwise, an Amendment would need to be filed and approved to include the industrial /commercial post- mining land use at a later date. Please respond. 7. The applicant has stated that explosives will be used during the mining operation. In accordance with Rule 6.4.4(i), the applicant must demonstrate through appropriate blasting, vibration, geotechnical and structural engineering analyses, that off -site areas will not be adversely affected by blasting.