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;,. I~I ~II~I~II~~~~~~I~ RAYE & ASSOCIATES 976 WELCH COURT •,G OLDEN, COLORADO 6040T`~~(303! 2344655 Apri l 24,1984 -RECEIVED. Mr. Uan Mathews APR 2 41984 Reclamation Specialist Colorado Mined Land Reclamation Division 1313 Sherman Street, Room 423 MINED LAND REClJ1MATI0N DIVISION Denver, Colorado 80203 Colo. Dept of Natural Resources Re: The Rockcastle Company - File C-039-81 Grassy Gap Coal Mine Permit Applica~ion Dear Dan: The purpose of this letter is to respond to the six deficiencies listed in your letter of April 3, 1984. The responses are listed below: There were 5 coal riders (numbered 1-5 from top to bottom) at Pit 4. Rider 1 existed only on the west side of Pit 4. It pinched out towa:-d the east and no longer exists. On April 6, 1984, The Rockcastle Company collected 2 samples from the overburden (identified as N (north) and S (south) Between Riders 1&2). Two samples were collected from the in- terburden between Riders 2&3, two from interburden between Riders 3&4, two from interburden between Riders 4&5, and one from the underburden below Rider 5. These nine samples were taken to a commercial laboratory and individually analyzed. Results are herein attached. When mining multiple seams, a stair-step type of mining scheme must be used to efficiently remove overburden and coal sequentially and backfill the void from the lowest removed coal seam with overburden from upper layers. The Rockcastle Company uses such a scheme. Pit 4 presently consists of two stair-steps. The dimensions of each are 900'x120'x15' and 900'x140'x47'. This equals a volume of about 280,000 cubic yards. The map of the active part of Pit 4 presented with responses submitted March 26 was not an accurate representation, but was meant to give a rough plan view of the active pit that could be easily correlated with the cross section provided through the active pit. The Rockcastle Company plans to continue moving up ^it 4 in this stair-step fashion. No detailed mine mip exists for Pit 4. Representative pre and post mining sections for Pit 4 have been prepared and are attached. These cross-sections were taken from the Mining Plan Map and the Reclamation Map. The Rockcastle Company can approximate the post mining contours shown on the Reclamation Map in the permit application. The existing hill is smooth contoured and gently sloping. A final contour that approximates the original contour can easily be achieved. 4. Three complete copies of the AVF reconnaissance map are attached. Progress Within Environments! Tolerances