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~~ ACZ Inc. <br />Engineering antl Environmental Services <br />1475 Pine Grove Roatl. Swte t09 <br />P.O. Box 774018 <br />Steamboat Springs, Colorado 80477 <br />303-879-6260 <br />April 3, 1992 <br />III IIIIIIIIIIIIIIII <br />999 <br />F-Sr_~;~`1.. <br />'v L i.,r <br />~~~ d 1997 <br />Ms. Cathy Begej '•Vllrl~+d ~~nC <br />Mined Land Reclamation Division ReC12Rt3tI0n D•„:,;,,n <br />1313 Sherman Street, Room 215 <br />Denver, Colorado 80203 <br />Re: EFC[ Southfield Mine (C-81-014), Technical Revision (TR-l4) for Reevaluation of Coal <br />Refuse Pile Stability <br />Deaz Ms. Begej: <br />Accompanying this letter aze three copies of a Technical Revision Application addressing <br />reevaluation of the stability analysis for the existing coal refuse stockpile. The technical revision <br />(TR-14) responds to specific Division concerns relative to variances in refuse placement practices <br />and consequent effects on refuse pile stability. This submittal is also designed to provide for full <br />abatement of NOV C-92-01. <br />With respect to Condition 1 of the NOV, EFCI completed remedial grading activities prior to the <br />cortesponding February l3, 1992 abatement date to insure effective drainage from the pile surface. <br />This submittal addresses NOV Conditions 2 and 3, providing the results of field sampling, material <br />testing, and revaluation of stability modeling input parameters and results relative to actual <br />measured material physical properties. Reevaluation of refuse pile stability resulted in a <br />determination that the existing pile configuration and placement practices are consistent with <br />applicable regulatory requirements. Modification of the pile and/or changes in refuse placement <br />methods aze, therefore, unwarranted and Condition 4 of the NOV is no longer applicable. <br />This submittal consists of the following specific components and is designed as a complete <br />descriptive package for placement in Exhibit 15, Minor and Technical Revisions: <br />• Technical Revision Application Form; <br />• Proposed Public Notice; <br />• Refuse Pile Stability Report (I/l4/92); <br />- Attachment A, XSTABL Computer Printouts <br />- Attachment B, Proposed Plan for De[ermination and Evaluation of Coal <br />Refuse Plasticity Values <br />- Attachment C, Coal Refuse Plasticity Results and Related Stability <br />Implications <br />Attachment D, 1988 Refuse Pile Stahilit~~ E~alu:ui~~n <br />