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pits, when utilty wastes are disposed in cuts prior to the construction of the cut with the critical pit crest, they will be kept at least twenty feet above the expected critical pit crest elevation. This will provide an extra margin of error if the actual critical pit crest elevation deviates from the expected. All utility wastes will have at least five feet of non-toxic wver plus topsoil (see Section 4.3.4.5). The disposal will be planned and controlled on a continuing basis to ensure that it does not adversely affect achieving approximate original contour (AOC). Trappers disposal plan attempts to preserve the maximum number of disposal options. This will help avoid concentrating large quantdies of utility wastes at a single location, which might affect AOC. Additionally, as discussed in Section 4.3.4.2, an average of 160 acre feet of utility wastes will have to be disposed each year. At this rate, only 32 acres would be required in a years time if the wastes are placed to an average depth of five feet. If d is determined that mining operations will cease for some reason, the Division will be notified in accordance with Sections 3.1.6 and 3.1.7. Utility wastes disposal will be discontinued wdhin 30 days after this notification unless otherwise approved by the Division. A monitoring program will be established as described in Section 4.8.5.2 to determine the occurrence of a leachate and ds movement, if any. Ashmore Pil In Ashmore pit, utility wastes will not be disposed closer than ten feet to the pft floor. Figures 4.3-23, 4.3- 24, 4.3-24a are cross sections of the three cuts in Ashmore pit where the "critical pit crest elevations" will occur. The cross sections show the "no utility wastes disposal zones" for the cuts they represent. How- ever, utility wastes will not be disposed in standing water in the north end of any cut. As an added pre- caution, utility wastes wit{ not be disposed wdhin fifty feet of the post-mining Johnson Guicfi, East and West No-Name and Middle Pyeatt drainages. The locations of post-mining drainages may vary up to 400 feet from the pre-mining locations. (Refer to Section 3.5.3). Therefore, no utility wastes will be disposed within 450 feet of the pre-mining locations (see map M47a) of any of the four drainages listed unless a plan showing the postmining location of the respective drainage is complete. If utilty wastes are disposed within the 450-foot buffer zone, a map showing the postmining drainage location will be avail- able at the mine sde for inspection. • 4-98b Revision: m2 -1 L ~ Approved: Noy i s ~s5a