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Roberts/M-77-407 adequacy 10/7/97 page 3 Detail A, shown on both map sheets, indicates slopes of a 3:1 gradient with a series cif runoff control ditches constructed at a specific interval on the slopes. I assume this to mean a commitment by the operator to maintain 3: I slopes throughout all mining phases. Please clarify if this is not correct. Also, please clarify whether the ditches will be built on a level contour or given a certain gradient toward some direction. Exhibit D -Mining Plan The description of the excavation during the phased mining plan is clearly written. M:y questions about the plan are fairly minor. Please describe here (or for Exhibit C, above) what the slope gradient will be during mining. Given the early ridge top method of mining, and the topography of the final parts of F'hase II, there is a good potential for rolling larger material or sloughing finer material down ttie hillslopes, and possibly allowing sediment or collected runoffto leave the site in an uncontrolled manner. Please provide more information about containing these materials, thiough practices or structures. This information may actually be details from the CDPHE discharge permit application. (If necessary, these may have to be indicated on a map also.) Please provide details about future processing, e.g., screening, crushing, hatching, etc., particularly containment of fluids. While topsoil is stockpiled for later use in reclamation, how will it be stabilized or protected? Exhibit E -Reclamation Plan Please clarify the apparently conflicting statements of whether fertilizer will or will not be used. The stated topsoil replacement depth of as little as three inches, and underlain by overt~urden replaced only if available, seems to indicate that "soil" as a mined commodity (see Application, page 1, item 5) may not be the best use of the scarce onsite soils. As requested in more detail below (under Exhibit F) please provide information related to the cobble discharge apron, runoff control ditches and fences. Exhibit F -Reclamation Plan Map Please depict the visual berm at the 6840 contour on the appropriate map (mining and/or reclamation maps) depending on which phase it will be present in. Please examine the stated acreages shown at the margin of the map: the total is more than the permit area. (It may be that the some of the Phase I slopes become Phase II pit floor.)