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Sixth Adequacy Letter, Amended CN -01 May Day Idaho Mine Complex, M- 1981 -185 borrow locations for the backfill material. Please identify the locations of the borrow areas for the backfill material. Please clarify the method of highwall reduction to be utilized at the May Day 1, 2 and 3 areas, and at the Chief Portal. 7. The configuration of the repaired channel for Little Deadwood Gulch at May Day 2 is illustrated on Figure D -1 of Attachment D -3, May Day 2 Stormwater Control Plan. Figure D -1 of Attachment D -3, illustrates that mine related debris will be removed from the channel and the impacted channel restored to a stable configuration. However, according to Figure F -3, May Day 2 Reclamation Topography, portions of the repaired channel will be buried in backfill material during final reclamation. As shown on Figure F -3, the backfilling of Little Deadwood Gulch commences at contour line 8835 and continues through contour line 8810. Figure F -3 does not indicate a channel across the backfill material necessary to convey the natural drainage. The proposed Reclamation Plan discusses removal of mine debris from the channel of Little Deadwood Gulch but does not discuss new backfill being placed in Little Deadwood Gulch. Please submit a revised Figure F -3, which shows the final configuration of all portions of Little Deadwood Gulch located within the affected land boundary, and which does not conflict with the proposed Reclamation Plan. 8. Figure F -5A, Chief Portal, Little Deadwood Gulch Reclamation Topography, indicates a near vertical highwall, approximately 30 foot high, which is in conflict with the 2H:1V permit conditions imposed in Exhibit 6.5. Additionally, Figure F -5A indicates the mine debris, inappropriately placed in Little Deadwood Gulch and subject of Violation MV- 2010 -020, will remain as a permanent fill in the channel, which is in conflict with the proposed Reclamation Plan. The Applicant has requested to resolve the issue through a follow -up Technical Revision and /or Amendment process subsequent to the conditional approval of CN -01. 9. Design specifications, certified by a licensed professional engineer, are required for all Environmental Protection Facilities under Rule 6.4.21(10), including the redundant containment measures required under Rule 6.4.21(7)(e). The Division had previously clarified that such designs were required for the following structures: • Mill building • Storage sheds, including Zircon or large shipping containers, in which designated chemicals are stored or utilized • Location of dewatering of tailings • Pipelines for tailings and recycled process water • Recycled process water storage tanks • Tailings disposal and /or storage locations • Sump or pit to contain leachate from stacked tailings 6