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0 <br />• Small drain sections should be extended to any seeps or springs found in site <br />specific investigations. When surface mining begins, sandstone seams which may <br />meet drain durability requirements (Fig. 5) will need to be identified and tested. <br />Methods to produce relatively uniform gradations of various sized drain rock will <br />need to be developed. <br />The types of drains desired (smaller drains with smaller rock sizes, or large <br />drains with large rock sizes) will depend on the availability of suitable rock and <br />processing requirements. If suitable rock is scarce, then additional analysis and <br />more refined crushing may be desirable to construct smaller drains. If suitable rock <br />is readily available then construction of large drains from large rock may be the best <br />alternative. <br />Fill Placement <br />CDMG regulations require that spoil be "placed in horizontal lifts in a <br />• controlled manner, concurrently compacted as necessary to ensure mass stability." <br />Maximum lift thicknesses are not specified. We understand current plans are to <br />transport spoil by mine trucks or by pushing downhill with a dozer. Lift thicknesses <br />on the order of 4 to 6 feet are planned. If the spoil consists of relatively coarse, <br />durable particles then thicker lifts may be possible. The general properties of the <br />spoil along with actual placement and compaction procedures will need to be <br />considered to determine if thicker lifts are reasonable. <br />Where spoil placement is performed by dozing the spoil down to the fill, care <br />should be used to place fill in near horizontal layers and not create fill layers which <br />slope down toward the fill face. This could result in adversely orientated layers of <br />finer spoil which could affect stability. <br />Inspection of the fill placement should be performed quarterly as required by <br />regulations to observe and document stripping, drain construction, fill placement, <br />. stability and surface drainage conditions. <br />LORENCITO COAL COMPANY <br />cTVr zs,zsi 14 <br />