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A. Pit Area <br />• - n.ai ' Pattern B',tabliskmsrt <br />Drainage courses were designed and constructed under the direction of a <br />registered professional engineer in accordance with the approved reclama- <br />tion plan. Drainage patterns were reconstructed using the pre-mine <br />U.S.G.S. topographic configuration as the base map. All disturbed drain- <br />age basins were graded to approximately the same base map configuration. <br />During final reclamation grading activities, the CMLRD requested the <br />Installation of additional drainage ditches to divert surface water runoff <br />from the disturbed area to and through approved sedimentation control <br />structures. Drainage modifications were requested by Mr. Mike Savage <br />(CMLRD Reclamation Specialist) in July of 1984. <br />Sun Coal Company caiq~leted the required modifications pursuant to CMLRD <br />request in late 1984. <br />A. Pit Area <br />- Slope Trrlinatian <br />Slur Coal Company returned the disturbed areas to slopes approved by C6¢,RD. <br />Sim Coal Company returned backfilled areas to slopes equal to or less than <br />3:1 wherever feasible and returned the bench outslopes to 2.5:1 as <br />approved by CMLRD's apprmrimate original contour variance criteria. The <br />• variance was approved by CMLRD based on a report submitted by Fox <br />Coru^ultants dated July 5, 1983. <br />As-built drasvirsls and field investigations were corY3ucted by CMLRD (Mr. <br />Brian Munson) and EnecoTech Inc.(Mr. George M.L. Robinson) to verify <br />compliance with slope requirements. All field and "in-house" slope <br />calculations verified CMLRD slope criteria were met. <br />A. Pit Area <br />- St~ider~oe of Instability <br />During mining (19TT-1980), Sun Coal Company did not encounter mass slope <br />failure in or adjacent to the pit. Prior to reclamation grading activities <br />Fox Consultants Inc (July 5, 1983) conducted a field reconnassance to <br />determine whether slope or pit instability could be a reclamation <br />problem. The results of the field study suggested mine backfilled slopes <br />can be graded to 2.5:1 without significant risk of overall instability. <br />During backfill grading activities and during routine on-going field <br />monitoring, no su~ficial or deep seated slumping has occurred, nor is <br />expected, on the beckfilled area. Sun Coal Company, however, has noted a <br />few areas where rills have formed on the backfilled areas. Sun Coal <br />Company has stablized, backfilled, topsoiled and revegetated these areas, <br />• whenever necessary. <br />- 208 - (Rev. 5/86) <br />