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• 2) Please submit topsoil redistribution depth information for Pit 4 as previously <br />discussed. <br />Response: Rockcastle completed sampling to document topsoil replacement <br />depths for the Prt 4 reclaimed area during the second week of October, 1991. <br />The Pit 4 disturbance has to this point been erroneously represented as <br />encompassing an area of approximately 135 acres. This acreage <br />corresponds to the Pit 4 disturbance boundary outlined in the original <br />Rockcasile permit application documents. Mining related disturbance in this <br />area is not as extensive as originally anticipated, and based on recent aerial <br />photographs, actual Pit 4 disturbance is approximately 55 acres. <br />Utilizing general guidelines based on conversations with Division Staff, <br />spacing of approximately 400 feet, with a 60 degree offset between sample <br />• rows, was utilized in selecting sample locations. These sampling parameters <br />resulted in collection of 16 samples (One sample per 4.2 acres) for the 55 <br />acre disturbance area. Sampling involved excavation using either a hand <br />shovel or auger to a depth at least six inches below the base of the replaced <br />topsoil. Both color and textural changes were utilized to identify the topsoil- <br />spoil boundary. Topsoil depth was determined by direct measurement and <br />recorded in the field to the nearest inch. <br />Appendix C, Pit 4 Topsoil Replacement Depth Documentation, included in this <br />response package, summarizes sampling results. Based on the sampling <br />data, mean topsoil replacement depth for the Pit 4 area is 21_ inches, with a <br />range of 9 to 37 inches. Standard deviation for the 16 samples is 9, with only <br />6 samples varying from the mean value by more than one standard deviation. <br />3) Maintain all perimeter ditches and culverts to ituure that all disturbed area <br />. drainage is routed to Pond 4. Check previous inspection reports for details. <br />-3- <br />