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DRAFT <br /> XVII. Backfilling and Grading (2.05.3(3) , 2.05. 3(9) , 2.05.4(2) (a) , 2.05.4(2) (c) , <br /> 4.09, 4.13, 4.14) <br /> (A PORTION) <br /> Rock Tunnel Refuse Pile <br /> The application includes the construction of a rock tunnel to be used to haul <br /> coal from the No. 1 and No. 2 mines to the base of the steep slope portion of <br /> the Basin's road system. This tunnel will allow discontinued hauling of <br /> coal by truck, which will greatly decrease impacts upon the Coal Basin <br /> environment and significantly reduce hazard exposure for the truck drivers <br /> and other mine personnel. The rock tunnel and its associated 320,000 cubic <br /> yard waste pile was reviewed and approved as a technical revision during 1979 <br /> and 1980. The approval of the tunnel and its associated underground development <br /> waste pile stipulated the installation of ground water monitoring wells in and <br /> adjoining the refuse pile. The application has been amended, in response to <br /> Division requests in the Preliminary Adequacy Review, to include monitoring <br /> results collected to date and to state the company's intent to conform with <br /> the original stipulations. The rock tunnel refuse pile is, therefore, in <br /> conformance with the requirements of Rule 2.05.3(9) and 4.09. <br /> Post-Mining Topography <br /> The application has been amended, in response to the Division's Preliminary <br /> Adequacy Review, to include a request for variance from approximate original <br /> contour reconstruction based upon steep slope mining conditions. For a discussion <br /> of this item, see Section XXIV, "Special Categories of Mining". The appli- <br /> cation also includes a request to defer final road reclamation design until <br /> the completion of further observations. For a discussion of this topic, see <br /> Section XX, "Roads". <br /> Insufficient information is contained within the application to judge stability <br /> of the proposed final reclamation backfilling and grading plan for the five <br /> mine portal benches. In accordance with Rules 4.14 and 4.27, the applicant is <br /> required to demonstrate that the proposed regraded configuration will achieve <br /> a minimum static slope safety factor of 1.3. Because the five mine portal <br /> benches now exist in their proposed maximum state of disturbance and reclama- <br /> tion will not occur until cessation of mining (approximately 40 years in the <br /> future) , this topic is amenable to stipulation. The Division finds that the <br /> following stipulation is necessary for a finding of compliance with the <br /> backfill and grading requirements of Rules 2.05.3(3) , 2.05.4(2) (c) and 4.14. <br /> Stipulation: <br /> THE DIVISION DIRECTS MID-CONTINENT RESOURCES, INC. , TO COMPLETE A <br /> THOROUGH GEOTECHNICAL INVESTIGATION AND STABILITY ANALYSIS OF THE <br /> PROPOSED BACKFILLED CONFIGURATIONS FOR THE FIVE PORTAL BENCHES AT <br /> THE COAL BASIN MINES. THE PURPOSE OF THIS PROJECT SHALL BE TO <br /> DEVELOP SPECIFIC BACKFILLING, GRADING, DRAINAGE AND RECLAMATION <br /> PROCEDURES TO ASSURE OPTIMUM STABILITY OF THE FINAL RECLAIMED PORTAL <br /> BENCHES. <br />