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pits, when utility wastes are disposed in cuts prior to the construction of the cut with the critical <br /> pit crest, they will be kept at least twenty feet above the expected critical pit crest elevation. <br /> This will provide an extra margin of error if the actual critical pit crest elevation deviates from the <br /> expected. <br /> All utility wastes will have at least five feet of non-toxic cover plus topsoil. The disposal will be <br /> planned and controlled on a continuing basis to ensure that it does not adversely affect <br /> achieving approximate original contour (AOC). Trapper's disposal plan attempts to preserve the <br /> maximum number of disposal options. This will help avoid concentrating large quantities of utility <br /> wastes at a single location,which might affect AOC. Additionally, as discussed in Section 4.3.4.2, <br /> an average of 160 acre feet of utility wastes will have to be disposed each year. At this rate, <br /> only 32 acres would be required in a year's time if the wastes are placed to an average depth of <br /> five feet. If it is determined that mining operations will cease for some reason, the Division will be <br /> notified in accordance with Sections 3.1.6 and 3.1.7. Utility wastes disposal may be continued <br /> until such time as all mine-related disturbance has been reclaimed. <br /> A monitoring program will be established as described in Section 4.8.5.2 to determine the <br /> occurrence of a leachate and its movement, if any. <br /> Ashmore Pit <br /> In Ashmore pit, utility wastes will not be disposed closer than ten feet to the pit floor. Figures 4.3- <br /> 23, 4.3-24, 4.3-24a are cross sections of the three cuts in Ashmore pit where the "critical pit crest <br /> elevations" will occur. The cross sections show the "no utility wastes disposal zones" for the cuts <br /> they represent. However, utility wastes will not be disposed in standing water in the north end of <br /> any cut. As an added precaution, utility wastes will not be disposed within fifty feet of the post- <br /> mining Johnson Gulch, East and West No-Name and Middle Pyeatt drainages. The locations of <br /> post-mining drainages may vary up to 400 feet from the pre-mining locations. (Refer to Section <br /> 3.5.3). Therefore, no utility wastes will be disposed within 450 feet of the pre-mining locations (see <br /> map M47a) of any of the four drainages listed unless a plan showing the postmining location of <br /> the respective drainage is complete. If utility wastes are disposed within the 450-foot buffer <br /> zone, a map showing the postmining drainage location will be available at the mine site for <br /> inspection. <br /> Revision: 01�L-Z-2- <br /> Approved, , <br />