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-53- XVI. EXPLOSIVES (2.05.3(6)) The Orchard Valley Mine is an existing underground operation. No regular surface blasting occurs. There is a slim chance that surface blasting will be utilized during construction of the rock slope tunnels. If material larger than what conventional earthmoving equipment can accommodate is found, less than five pounds of explosives would be used to break up the material. The operation is in compliance with all requirements related to explosives use. XVII. BACKFILLING AND GRADING (2.05.3(3)(b). 2.05.3(9), 2.05.4(2)(a). CWI's application fora permit for the Orchard Valley Mine proposes a reclaimed final configuration for the surface facilities areas of the mine which consists of a partial backfilling scheme. In the preliminary adequacy review of the original permit application, the Division stated that it considered their proposal to be inadequately supported within the application. Further, the Division required the applicant to complete an appropriate geotechnical and stability analysis to demonstrate that the proposed final configuration would be stable and would satisfy the requirements of Rule 4.14 and 4.27, "Operations on Steep Slopes". The results of the analyses would then be utilized by the applicant to prepare a detailed engineering design which conforms with the above enumerated regulations. CWI retained the services of Merrick and Campagy and Geo-F(ydro Consultants, Inc. to investigate the slope stability of the entire surface facilities area at the Orchard Valley mine. Phase I of this study was completed and a summary report, prepared by Geo-Hydro Consultants, Inc. was submitted to the Division for review on July 21, 1981 (See Volume 6). The analysis, prepared in accordance with the present state-of-the-art of geotechnical analysis, determined that no immediate major hazards existed at the mine site. The report does observe, however, that some local stability problems exist and the factors of safety of individual cuts and fills will have to be increased by redesign and reconstruction to achieve a stable final reclaimed configuration, in accordance with the regulations. CWI's geotechnical consultants, Geo-Hydro, Consultants, Inc., completed the Phase II analyses on April 15, 1982, in accordance with the stipulated requirements of the originally approved Permit (See Volume 6). The stipulated tasks of the Phase II analyses included evaluation of nearby landslides mapped by the Colorado Geological Survey; completion of test drilling and test pits; installation of monitor wells; soil and rock testing; and the completion of a series of stability analyses for current slope configurations of the existing surface facility area at the Orchard Valley mine. CWI, in conformance with recommendations made by its geotechnical consultants, has installed sophisticated tilt-metering devices within several of the fill benches which exist within the surface facilities at the Orchard Valley mine. The purpose of these devices is to collect additional geotechnical data with which to verify past analytical assumptions and with which to com{~lete final analysis and design, originally stipulated as Phase III of the surface facility studies, within the approved original permit.