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X. Backfilling and Grading - Rule 4.14 <br />BRL's application for a permit for the Bowie No. 1 East Mine proposed a reclaimed final <br />configuration for the surface facilities areas of the mine which consists of a partial <br />backfilling scheme. In the preliminary adequacy reviewof the original permit application, <br />the Division stated that it consideredtheirproposalto be inadequately supportedwithin the <br />application. Further, the Division required the applicant to complete an appropriate <br />geotechnical and stability analysis to demonstrate that the proposed final configuration <br />would be stable and would satisfy the requirements of Rules 4.14 and 4.27, "Operations on <br />Steep Slopes." The results oftheanalyses wouldthen beutilized bythe applicant toprepare <br />a detailed engineering design which conformed to the above regulations. <br />The operator retained the services of Merrick and Company and Geo -Hydro Consultants, <br />Inc. to investigate the slope stability of the entire surface facilities area at the Orchard <br />Valley (Bowie No. 1) Mine. Phase I of this study was completed and a summary report, <br />prepared by Geo -Hydro Consultants, Inc., was submitted to the Division for review on <br />July 21, 1981 (See PAP Volume 6). The analysis, prepared in accordance with the present <br />state-of-the-art of geotechnical analysis, determined that no immediate major hazards <br />existed at the mine site. The report does observe, however, that some local stability <br />problems exist and the factors of safety of individual cuts and fills will have to be increased <br />by redesign and reconstruction to achieve a stable final reclaimed configuration, in <br />accordance with the regulations. <br />Geo -Hydro, Consultants, Inc. completed the Phase II analyses on April 15, 1982, in <br />accordance with the stipulated requirements of the originally approved Permit (See PAP <br />Volume 6). The stipulated tasks of the Phase II analyses included evaluation of nearby <br />landslides mapped by the Colorado Geological Survey, completion of test drilling and test <br />pits, installation of monitor wells, soil and rock testing, and the completion of a series of <br />stability analyses for current slope configurations of the existing surface facility area at the <br />Bowie No. 1 Mine. <br />The operator, in conformance with recommendations made by its geotechnical consultants, <br />has installed sophisticated tilt -metering devices within several of the fill benches which <br />exist within the surface facilities at the Bowie No. 1 Mine. The purpose of these devices <br />was to collect additional geotechnical data with which to verify past analytical assumptions <br />and with which to complete final analysis and design, originally stipulated as Phase III of <br />the surface facility studies, within the approved original permit. <br />Utilizing the results of Geo -Hydro, Consultants, Inc.'s analyses, Merrick & Company, Inc., <br />design consultant to the operator, completed a Phase II amended design for the drainage <br />facilities at the existing surface facility area of the Orchard Valley (Bowie No. 1) Mine. <br />T he operator also completed a detailed stability analysis and redesign of the proposed final <br />reclaimed configuration for the surface facilities at the mine. This design was submitted <br />and approved in Technical Revision No. 28. The cut and fill areas were restored to their <br />approximate original contour except for an access road which will remain following <br />reclamation. The access road will be within a 20 foot wide terrace corridor associated with <br />the access road. <br />31 <br />