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M-98-055/Adequacy letter 7/2/98 page 3 Please indicate what the gradient of the sideslopes of the pit will be maintained at during mining. (Remember, the bond for.the site is calculated based on reclamation costs, which are affected by the number of disturbed acres to revegetate and the amount of earthwork necessary to bring the mined condition to the reclaimed condition, among other things. Therefore, steeper slopes during mining cost more to reclaim to gentler slopes.) The south end of the existing pit is deeper than ten feet (it is about 20 feet deep). Your new mining plan states that mining will go no deeper than ten feet. Will you backfill any part of the existing deeper portion? Please comment. Exhibit D -Reclamation Plan You state that drainage is primarily in the form of sheet flows, and grading will contain and divert these flows around the pit. I will comment on these factors under Exhibit E. The site is surrounded by rangeland and will be returned to rangeland. Please address the potential need for fencing to exclude grazing livestock during revegetation phases of reclamation. It appears that you propose to disturb the full 9.99 acres prior to commencing the final reclamation. Is that correct? Exhibit E - Premining/Mining and Reclamation Maps The Premining/Mining Map does not include any details of the plan within the 9.99-acre boundary. Please indicate the locations of existing and future stockpiles, roads and ramps, direction of mining, pit areas, etc. Also, there are no right-of--way fences shown, or other landowners within 200 feet. Please show the "owner" of the highway and its fences, and the owner(s) of land across the highway. There is scant topographic information depicted. By interpolating from the existing 40-foot interval contours, it seems that there is a uniform slope of about 8% across the slope (west to east). Is this correct? Also, there is an intermittent drainage marked which passes through the center of the site. This is also shown on the vicinity map on that page, which shows this drainage basin as being at least 200 acres in size, without including its off-map area. The diversion ditch drawn on the map sheet will presumably be used for stormwater control, but its location is not shown, nor is its size described in relation to any specified storm event. Please provide these items. The Reclamation Plan Map also does not include much topographic information. The intermittent drainage shown on the premining map is still shown here, unchanged, though it seems that it will not flow the same. Please revise this aspect, with attention given to the stormwater diversion structure as needed.