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With the coal reserves defined and equi pment chosen, it becomes the engineer's task to design a facilities site plan, mining plan, ground co trol plan, haulage road system, surface water control plan, • sediment control plan, power distribution system, postmine contour configuration, and a variety of inter-related projects. The processing an support facilities are generally located at a site near the center of the reserves in order to balan a haulage distances. Factors such as topographic relief, strength of foundation materials, adequac of drainage and accessibility are normally considered in the engineering design. The design of a mini g plan is governed by several factors, including economic considerations, drainage patterns, relief, sl pe, and geologic structures. Normal pit progression would begin at a "cropline" (outcropping) or s allow area and progress toward the deeper coal. The advantage of this technique is a lower prod uction cost in early years. However, the cost of production becomes progressively higher s the pits advance. At Seneca II-W, the, topography and geologic structure dictate pit orientation and progression. In the main II•W area, more uniform overburden depths favor pits oriented perp endicular to the cropline while rapidly increasing overburden depths in the II-W South area favor pits oriented parallel to the cropline. The best techniques for orientation of pits with respect to drainage patterns are to lay out a sequence of pits where the natural drainage is away from or parallel to the its. The techniques used at Seneca II-W to tleal with the relatively high relief, slopes, and geologic tructure will discussed in the following section. A haulage road system is designed with roads of ppropriate width and grade to accommodate the intended traffic. In mountainous terrain the constru lion of switchbacks is sometimes necessary to maintain the flattest possible grade and minimize the area of disturbance. Safety berms will be utilized where required by steep side slopes. Surface water control plans normally utilize ditches for overland • diversion of surface water as well as pit umps for collecting and handling surface and ground water that enter the pit. Sediment ponds are designed for controlling runoff from disturbed areas. All diversions and sediment ponds are desi ned in accordance with the regulations governing such structures and conform to currently accep ed engineering practice. Power distribution at area surface mines such as Seneca II-W, which utilizes high voltage electrical equipment, must be well planned for optimum accessibility. Power for strippin equipment is normally fed from the highwall or undisturbed side of the operation for ease of access a d to alleviate congestion in the pit and on the spoil side. A very important task requiring utilization of the best available engineering techniques is the design of a stable postmine land surface. Determinati n of such factors as spoil swell, stream gradients, postmine land use, spoil character, and foundation aterials will affect the design of a land surface representing the approximate original contour. The cu rently accepted technique is to design a surface with slopes that do not exceed the average premining lope and with a general configuration that approximates the premining surface. Area surface mining is the most efficient method of recovery of a coal resource, especially in areas such as Seneca II-W where the coal is of such a quality that it can be burnetl "raw", that is, without processing. The Wadge Coal seam will b mined to approximately 100 feet in depth (limitation of the stripping equipment) with a resource reco ery rate approaching 95 percent. Table 12-2, Annual Coal • Productions illustrates the actual and nticipated acres mined and actual and proposed annual production of coal from September 1, 1 90 through the currently proposed life-of-operations. It is highly unlikely that the areas proposed PR04 I 4 Revised 04/04