2016-07-21_REVISION - M1980244 - Laserfiche WebLink

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Adequacy Review (AM-11) – Elliott Russell July 21, 2016 Page 2 of 6 structures/practices that will be installed/implemented to protect the plant growth medium resource from leaving the stockpile during precipitation events (for example: silt fencing, tow berms, etc.). 8. On page 12-1 of Volume I, the applicant states the majority of affected lands will be returned to rangeland and wildlife habitat. Please clarify if lands other than the majority only include the preserved historic resources and interpretive guidance for the public. 9. On page 12-1 of Volume I, the applicant states that roughly six inches on growth medium will be replaced. The Division typically suggests Operators to allow flexibility in their reclamation plans by proposing a range of topsoil replacement (e.g., 6 inches to 12 inches) rather than specific figures. The Division requests the Applicant commit to replacing no less than six inches of topsoil on all reclaimed areas. Please specify the range of depths to which topsoil will be replaced. 10. On page 12-1 of Volume I, the applicant states plant growth medium will be replaced on the overburden storage areas, select haul roads into the surface mines, certain surface mine backfills, the re—contoured valley leach facilities, support facility sites, reclaimed portal area, and other ancillary disturbance areas. Please summarize and specify the size of any areas that will not have plant growth medium replaced for reclamation and indicate these areas on the Exhibit F Reclamation Plan Map (Drawing F-1: Approximate Post Mining Topography). 11. On page 12-1 of Volume I, the applicant specifies that approximately 2.4 million cubic yards of growth medium will be required and approximate 3.21 million cubic yards of growth medium are available from the existing and future development areas. On page 12-1 of Volume I, the applicant specifies that there are 4,667 disturbed acres. If at least 6 inches of topsoil is returned to all disturbed lands, this will require approximate 3.77 million cubic yards. Please clarify this discrepancy. 12. Please commit to replacing all stockpiled plant growth medium. If an excess of stockpiled plant growth medium is available, the Division suggest implementing a variable topsoil replacement project to mimic more natural and pre-mining conditions where at least 6 inches of topsoil will be replaced on the crests of hills and ridges and more would be replaced in the lower portions of hills and valleys. 13. On page 12-1 of Volume I, the applicant discusses that that reclaimed slopes will be graded to 2.5H:1V or gentler unless steeper slopes are required to blend with surrounding topography or to create irregular landforms with a more natural appearance. Please clarify the maximum slope of this blending and irregular landforms and indicate these areas on the Exhibit F Reclamation Plan Map (Drawing F-1: Approximate Post Mining Topography). 14. On page 12-2 of Volume I, the applicant discusses that that reclaimed slopes may be plated with rock to protect against storm water runoff erosion and to emulate historic underground development rock piles in the Mining District. Please clarify the maximum size of a rock-plated area and indicate these areas on the Exhibit F Reclamation Plan Map (Drawing F-1: Approximate Post Mining Topography). 15. On page 12-2 of Volume I, the applicant states that compacted areas from traffic or placement of structures that are identified for reclamation will be ripped prior to topsoil replacement to facilitate revegetation. Please specify to what depth with the compacted areas be ripped to. 16. On page 12-2 of Volume I, the applicant states that in general, approximately six inches of growth medium is intended to be replaced at reclamation sites. Similar to adequacy issue #9 above, the Division requests the Applicant commit to replacing no less than six inches of topsoil on all reclaimed areas.