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,e <br />-23- <br />The mining and reclamation plan at the Trinidad Basin Mine is designed to insure <br />contemporaneous reclamation and return the mined area to approximate original <br />contour. <br />The Trinidad Basin Mine is a contour strip mine. Briefly described, the operational <br />scheme consists of a series of five pits, one of which has been completed to <br />date. Within each pit, the primary cut is excavated and the overburden material <br />temporarily stored in overburden stockpiles. Successive cuts are then excavated <br />and overburden carried back and placed ifs the preceding cut. Upon completion of <br />the final cut of any pit, material is them transported from the temporary over- <br />burden stockpiles to backfill the remainder of the final pit cut. <br />Trinidad Basin Mining has projected a 16`; inherent swell factor for the overburden <br />encountered at their mine. More than offset by coal extraction, this inherent <br />swell of overburden appears to result in a slight deficit of back filled material. <br />This deficit will result in a post-minincr topography slightly below that of the <br />pre-mining configuration. The applicant has indicated that its projection of <br />overburden swell is based upon the analysis of previous mining results at the <br />Trinidad Basin Mine. In order to allow verification of this analysis, the Division <br />deems it necessary to impose the following stipulation upon approval of the permit: <br />Stipulation No. 14: <br />THE DIVISION DIRECTS TRINIDAD BASIN MINING TO SUBMIT THE DATA AND <br />ANALYSIS OF OVERBURDEN SWELL AND 19RTERIAL BALANCES RELIED UPON BY <br />THE COMPANY TO PROJECT OVERBURDEN SWELL FACTORS FOR THE TRINIDAD <br />BASIN MINE. THIS INFORMATION AND A REPORT OF THE ANALYSIS SHALL <br />BE SUBMITTED TO THE DIVISION FOR REVIEW WITHIN 30 DAYS FOLLOWING <br />APPROVAL OF THE PERMIT. THIS INFORMATION SHALL INCLUDE DISCUSSION <br />OF PP.EVIOUS PIT VOLUMES, PRE- AND POST-MINING TOPOGRAPHY OF <br />PREVIOUSLY MINED AREAS, INCLUDING PROPOSED AND EXISTING ROAD <br />CONFIGURATIONS, APJD OVERBURDEN STRATIGRAPHY AND SWELL CHARACTERISTICS, <br />AT A MINIMUM. MINING SHALL NOT PROCEED BEYOND CUT NO. I3 OF PZT <br />NO. 9 PRIOR TO WRITTEN APPROVAL BY THE DIVISION OF THIS ANALYSIS. <br />The operator has submitted material balance calculations based upon its pro- <br />jections of overburden swell at the Trinidad Basin Mine. The Division's examination <br />of the projections contained upon amended Table V-l, determined that calculation <br />or typographic errors were contained within the amended table. Recalculation of <br />these tabulated material volumes has determined that the company's material balance, <br />assuming the Z6o overburden swell factor, projects an overall material deficit of <br />approximately 52,700 cubic yards of material. The company should amend its post- <br />mining topographic maps and narrative descriptions to depict and describe its plan <br />to accommodate this deficit of backfill rn.sterial. In order to assure resolution <br />of this entire concern prior to a stage in the mining operation which will allow <br />flexibility in accommodating the backfilled deficit among the various pits and <br />stockpiles, the Division deems it appropriate to impose the following stipulation <br />upon permit approval: <br />