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RULE 4 PERFORMANCE STANDARDS <br />surveyed configuration of the pit and reclaimed areas, the permittee will determine the overall <br />overburden swell and the resultant variation between premining and post-mining topographic <br />elevation for the mined areas. Further, the permittee will ascertain, record and report to the <br />Division the proportions of overburden excavated using truck/shovel and dragline methods. The <br />maps and a report presenting the methodology and results of the required determinations will be <br />submitted to the Division for review and approval on an annual basis. The permittee will <br />continue these monitoring procedures on an annual basis until the Division determines the results <br />sufficient to adequately verify overburden swell factor projections and approves, in writing, <br />cessation of monitoring. The maps will include a comparison of proposed and actual reclaimed <br />contours and will be submitted annually throughout the permit term." Excerpted from Colowyo <br />Findings and Proposed Decision to Approve Permit File No. C-019-81, September 28, 1982. <br />The results of the monitoring can be found in the 1983 - 1982 Annual Reports. <br />In the 1986 Annual Report, Colowyo requested a reduction in the overburden swell factor monitoring <br />from an annual frequency to once every two and on-half years, and in a letter dated May 12, 1987 the <br />MLRD stated that they were prepared to approve the reduction, which was made effective upon permit <br />renewal. <br />In the 1992 Annual Reclamation Report, Colowyo requested that the swell factor monitoring and analysis <br />requirement be terminated. On August 11, 1993, Colowyo submitted a request for a minor revision to C- <br />81-019 to facilitate the termination of this monitoring. <br />The mining plan, as described in Section 2.05.3, is a soundly designed and engineered open pit mining <br />plan, which maximizes coal conservation and recovery while minimizing adverse environmental impacts. <br />Because of the multi-seam mining configuration planned by Colowyo, an exemption from the 180 day or <br />four spoil ridge limitation remains necessary. The mining plan has been designed as a continuously <br />moving open pit operation with the mine advancing approximately parallel to the dip of the numerous <br />coal seams. The initial box cut for the operation was made on the south side of Streeter Draw. The <br />mining operation is designed to progress in a southward direction with shovels/trucks/ proceeding along <br />the entire length of the mining area uncovering the upper coal seams and the draglines uncovering the <br />lower coal seams as shown on the mining range diagram (Map 24). With the numerous benches used in <br />an open pit operation, the mine area will be opened for some time until the equipment comes back to <br />initiate another pass on a designated bench. <br />As the mining operations remove coal seams (In the southward progression), the mining area must be left <br />open until such time as the lower-most coal seam can be recovered. With the mining configuration, the <br />time differences between mining the upper-most seam versus the lower-most seam will obviously be <br />greater than 180 days. As the operation advances, backfilling will be as contemporaneous as practical but <br />not so as to interfere with removal of the lower-most coal seam. Colowyo will rough backfill and grade <br />as shown on the Spoil Grading Map (Map 29) by methodically and actively dumping and backfilling <br />overburden in the West and East pits very close to final contour so that minimal work will be needed to <br />complete final re-grade of these areas in the future. All disturbed areas will be returned to the <br />approximate original contour by grading and backfilling with the use of a dragline, trucks, dozers, <br />scrapers and dozers assisting a dragline. Additional detail of the backfilling and grading for the mining <br />operation is set forth in the discussion under Sections 2.05.3 and 2.05.4. <br />The area to be mined will be restored to a topography approximating premining grades. The outslopes of <br />the completed fill in Streeter Draw and areas backfilled, as necessary, will utilize terraces and/or contour <br />furrows for erosion control and stability. These terraces and contour furrows will be constructed <br />according to the requirements outlined in Section 2.06.2. Where applicable, Colowyo will retain all <br />Rule 4 Performance Standards 4.14-2 Revision Date: 6/5/09 <br />Revision No.: TR-80