PERMFILE117644 - Laserfiche WebLink

Home Browse Search

• percent slopes) and shallow depth to bedrock. The salvageable topsoil from these units will primarily be utilized, whenever feasible, in postmine dry pastureland areas where postmine contours exceed 10 percent slope. One-lift topsoil will be isolated from the two-lift topsoil during all soil handling operations. Irreversible structural damage would occur to these soils if they were salvaged while saturated. Therefore, topsoil salvage equipment will generally be limited to the drier areas. Wet areas will be dewatered and allowed to dry prior to salvage. Appropriate adjustments will be made to the recovery rate as dictated by actual field conditions and initial topsoil balance reports. The actual amount of topsoil salvaged has been less than the amount estimated in the soil survey. Tables 2.05.4(2)(d)-1 (1988 disturbance) has been revised to reflect the actual salvage and perceived future topsoil salvage quantities. As of July 1994, W FC has experienced an overall recovery of 80 percent. Table 2.05.4(2)(d)-2 reflects estimated salvage quantities for the 1996 disturbance area and Table 2.05.4(2)(d)-3 reflects estimated salvage quantities for the 1999 disturbance area. Topsoil Salvage Techniques -Year 2001 and onward. At the mine's option, The topsoil will be salvaged using the techniques described in the section above, or by the following method: the Lift A topsoil will be stripped in one lift by mine dozers into short-term (<90 days) stockpiles adjacent to the upper pit highwalls. As the shovel nears the topsoil pile during the course of its normal excavation, a dozer will push the topsoil to the shovel for loading into haul trucks. The haul trucks will transport the material to the spoil side for direct laydown or stockpiling. If direct laydown is used, the topsoil is spaced by haultruck dumping for push spreading by a mine dozer. The laydown thickness is determined by the amount of material immediately in front of the pit versus the available spoil area behind the pit, with minimum goal of approximately one foot of laydown thickness. The dozer operater will be guided by either fill stakes in front of the push or by test boring after the push. Because of this process, topsoil redistribution will no longer consist of phased campaigns as in the past, but will be an integral, ongoing portion of the mining operation. The Lift B material will consist of suitable material selected from the upper bench and is essentially the same as the uppermost four foot of regraded spoil as described in an earlier section. • (Revised 24 AUG O6) 2.05.4(2)(d)-13