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-2- <br /> FURTHER, MID-CONTINENT RESOURCES, INC. , SHALL PREPARE A DETAILED <br /> MATERIAL BALANCE, DESIGNATING THE PROPOSED SOURCE OF MATERIALS TO <br /> BE UTILIZED IN COMPLETING THE BACKFILLING AND GRADING OF THE MINE <br /> PORTAL AREAS. <br /> MID-CONTINENT RESOURCES, INC. , SHALL SUBMIT THE REPORT OF THE GEO- <br /> TECHNICAL INVESTIGATION AND STABILITY ANALYSIS, THE DETAILED MATERIAL <br /> BALANCE, AND A DETAILED PORTAL BENCH RECLAMATION PLAN TO THE DIVISION <br /> FOR REVIEW PRIOR TO DECEMBER 31, 1983. <br /> XVIII. Coal Processing Waste and Non-Coal Processing Waste (2.05.3(8) , 2.05.4(2) (f) , <br /> 4.10, 4.11) <br /> (A PORTION) <br /> Coal refuse from the coal preparation wash plant at the Coal Basin mines is <br /> currently deposited by conveyor and front end loader in an approved area to <br /> the east of the wash plant. Coal refuse has been deposited at this site <br /> continuously since 1961. As of the spring of 1981, the company estimated that <br /> approximately 1.5 million cubic yards of coal refuse had been deposited within <br /> this pile, attaining a maximum height of 125 feet with a facial angle of 380. <br /> Mid-Continent Resources, Inc. , had a geotec_hnical investigation and stability <br /> analysis prepared for the existing and projected waste pile configurations. <br /> Morrison Knudsen, Inc. , and Whaller and Associates, Inc. , participated in <br /> the performance of these analyses. The stability analysis, completed in <br /> accordance with the prudent state-of-the-art of embankment stability analysis, <br /> determined that the existing pile configuration achieved a static slope safety <br /> factor of 1.5. Further, the analysis projects that a static slope safety <br /> factor in excess of 1.56 will be achieved for the proposed ultimate pile <br /> configuration of a 270 facial slope and a maximum height of 300 feet. This <br /> proposed ultimate configuration will accommodate approximately 10 million cubic <br /> yards of coal refuse waste. <br /> In preparing the stability analysis, Morrison Knudsen, Inc. , employed material <br /> strength test results obtained by testing performed by Whaller and Associates, <br /> Inc. These analyses were performed on specific samples of waste and foundational <br /> materials obtained at the site through test augering and pit sampling. The <br /> material strength testing was performed in accordance with acceptable testing <br /> methods. The analysis assumed that the refuse pile had a sufficiently high <br /> permeability to prevent pore pressure buildup. This assumption must be verified <br /> by appropriate drilling and monitor well installation. The Division finds <br /> that the following stipulation is necessary for a finding of compliance with <br /> the requirements of Rules 2.05.3(8) , 2.05.4(2) (f) , 4.10 and 4.11. <br /> Stipulation: <br /> THE DIVISION DIRECTS MID-CONTINENT RESOURCES, INC. , TO INSTALL AND <br /> MONITOR GROUND WATER MONITORING WELLS ABOVE, WITHIN AND DOWNSLOPE FROM <br /> THE COAL PROCESSING WASTE PILE AT THE COAL BASIN MINES. THE COMPANY <br /> SHALL SUBMIT PROPOSED LOCATIONS FOR THESE MONITORING WELLS TO THE <br /> DIVISION FOR REVIEW AND APPROVAL WITHIN 30 DAYS FOLLOWING THE ISSUANCE <br /> OF THE APPROVED PERMIT. FURTHER, THE COMPANY SHALL COMPLETE INSTAL- <br /> LATION OF THE APPROVED MONITORING WELLS WITHIN 90 DAYS FOLLOWING <br /> ISSUANCE OF THE APPROVED PERMIT. COMMENCING WITH THE INSTALLATION <br />