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State Reg. <br />• OVERBURDEN HANDLING OPERATIONS - <br />2.05.3(1), As mentioned previously (under "Mining Operations <br />2.05.3(6) Life-of-Mine"), the geologic conditions at Seneca II are such <br />that the operation cannot be conducted by utilizing <br />conventional area mining methods. In a conventional area <br />surface mine, the coal seam being mined lies in a relatively <br />level plane with the outcrop at a lower elevation with respect <br />to the surrounding terrain. As the elevation rises, the <br />overburden becomes deeper. During development of a <br />conventional pit progression plan, the mine would be opened <br />along the outcrop with a "box cut" pit generally paralleling <br />the strike of the coal seam. Mining would then progress in the <br />direction of higher surface elevations with each successive pit <br />excavating deeper overburden. Operations then continue until <br />the overburden becomes too deep and exceeds the physical <br />capability of the primary excavation equipment or becomes <br />uneconomical due to the high costs involved. <br />• At Seneca II, the conventional development techniques have been <br />modified with some very beneficial results. With the coal <br />outcrop at the higher elevations, it is virtually impossible to <br />mine along the cropline and progress toward the deeper coal. <br />Far one reason, each successive pit would be made at a lower <br />elevation and the overburden would have to be cast uphill into <br />the adjacent open pit. This would place severe limitations on <br />the dumping height and operating radius of the dragline as well <br />as create a very unstable and unsafe, spoil configuration. <br />Another reason is that coal haulage trucks cannot safely <br />operate on haulage routes that parallel the strike of the coal <br />surface unless considerable extra road building effort is <br />expended in each pit. <br />As mentioned earlier, each pit is oriented approximately <br />perpendicular to the strike of the slope. The main reasons for <br />• this are increased safety, more efficient coal loading and <br />haulage, and relative ease of overburden removal. Two other <br />12-47 Revised 8/27/86 <br />