2002-07-03_PERMIT FILE - M2002004

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Exhibit D disturbed for each year of mining will vary, gradually increasing upslope. Figure D-1 illustrates the area • disturbed for each of the first 8 years of mining. A box cut of about 16 acres (1,400 feet long by 450 feet wide) with an average depth of 45 to 50 feet will initiate the operation and be connected to the adjacent plant by an excavated earth incline truck and access ramp oriented approximately parallel to the down-slope pit wall. Portions of this initial opening will remain open to allow equipment access to subsequent mine panels, and for containing the in-pit conveyor, sump, and drainage ditch. Subsequently, as noted above, the initial opening will be closed and the sump, collection drainage ditch, conveyor, and pit access ramp will be moved to the southeast. Material above the limestone from this initial cut will be stored in an area south and south-east of mining year blocks 4 and 5, as noted on Exhibit D-1, and temporarily revegetated for stabilization. (Pre-stripped materials from the Year 6 operating block (not illustrated) will be stored above the Year 15 mining block.) The highwalls at the northern and western edges and the sides of the earthen incline will be excavated with slopes not exceeding 70 percent. Final highwalls will be sloped 4H:1 V and stabilized to control erosion. See the Surface Water Management Plan (Appendix F) for a discussion of storm water controls. Mining of the limestone and up to 5 feet of bottom sandstone will continue from this box cut in a southwesterly direction as shown on Exhibit D-1. Incremental production panels will be established generally along strike. The panels are offset slightly relative to strike to achieve an overall slope along the pit floor in order to facilitate passive drainage to the sump (settling pond) located in the first year mining block. The dimension of weekly panels must be at least 24-feet wide by 600-feet long. There are, regardless of the thickness of the limestone layers, approximately 7,000 to 15,000 cubic yards of limestone to be removed in the weekly panels. The limestone to be removed is covered by an unconsolidated layer (including subsoil and topsoil) and shale approximately 0- to 45-feet thick in the area to be mined. The average yearly panel dimension foi• the first five years of mining will be • approximately 450- to 600-feet wide (upslope) by an average of 1,400-feet long by 20 to 30 feet in thickness of limestone (plus 1 to 6 feet of the Codell Sandstone) to maintain a proposed limestone production level of 1.5 million tons per year. The total area affected by mining in any one given year will be dependant on the thickness of limestone removed in order to maintain the annual production target. Areas undergoing active quarrying subject to wind erosion will be limited to 15.5 acres at any point in time. As each production block progresses, unconsolidated material and shale, along with topsoil and subsoil will be removed from the pre-strip areas and carried behind current production panels and placed on the pit floor from which the limestone and sandstone have been removed, or upon areas at which regraded unconsolidated materials and shale have been placed. This backfill material will be graded prior to subsoil and topsoil placement and seeding, sequenced according to weather conditions and seasonal revegetation periods. The combined area of active mining, processing, stockpiling, and reclamation will vary from year to year based on thickness of the various materials encountered and production requirements. Limestone blasting will occur once or twice per week, by a licensed blasting contractor following standard practices. Most blasting will occur in limestone, but on infrequent occasions the overburden will require low-level blasting. A short summary of blasting practices is listed below and discussed in the Rule 6.5 Exhibit. The specific blasting design detail summarized below represents typical conditions for estimating impacts from blasting and should not be considered permit conditions. Actual blast design will vary depending on the specific rock being broken, equipment on site, technology available, and the most efficient procedures and practices according to the experience and training of the licensed contractor responsible for the blast. 1. To achieve a powder factor of about 0.8 lb/ton, it is anticipated that 6.25-inch diameter holes will contain up to 360 pounds of blasting agents (ANFO) and an accelerator, with an approved delay • interval. 1180-Mine Permit Exhibits (Jul.03.02)FINAL.doe D-3 July 3, 2002