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III. COMMENTS -COMPLIANCE Below are comments on the inspection. The comments include discussion of observations made during the inspection. Comments also describe any enforcement actions taken during the inspection and the facts or evidence supporting the enforcement action. slope may experience soil and shallow weathered bedrock veneer failures analogous to the failure occurring on the substation cutslope. This slope will benefit from the installation of tiebacks or piling to prevent failure prior to the installation and backfilling of the surface diversion culvert along it's toe. Ventilation Shaft #3 Collar Elevation Change -cutslope Concerns Mr. Mende accompanied me to the bench constructed to serve as the collaz for the 10 foot diameter ventilation bore #3. The pioneer bore determined that the bedrock surface is approximately 25 feet lower than anticipated. MCC may desire to revise the elevation of the bench to excavate to competent bedrock. In the event this was done, the cutslope southeast of the collar would be increased in height by 25 feet, to approximately 50 feet. A 50 foot high cutslope in colluvium will require geotechnical evaluation to support design of a stable slope configuration. MCC should not excavate to bedrock prior to the submittal of an appropriate revision and subsequent approval from the DMG. Slides and Dama¢e In late March of 1997, a slide occurred within the cut slope above the Materials Storage Bench (MSB). The material bulge at the base of the slide had pushed out the concrete barriers on the uphill side of the road which accesses the bench. According to MCC staff, other sliding activity occurred in April, 1997 below the main Portal Bench and in the vicinity of the Wazehouse and Silos. In April, 1997 the DMG received telephone calls from MCC staff indicating that emergency construction work was required and underway in an effort to control slope movement and to protect various structures around the West Elk Mine. During these telephone conversations, MCC requested verbal approval to utilize subsoil from the cut slope above the MSB as fill material for the emergency construction work. The DMG granted this approval due to the emergency nature of the slide movement with the following conditions: 1) previously undisturbed areas would not be affected and 2) if such new new disturbance had occurred, then topsoil must be properly segregated and salvaged, and the quantities of topsoil and subsoil materials utilized or stockpiled must be quantified and updated in the permit document. ' On May 1, 1997 the DMG received a letter from MCC informing us that they are experiencing spring-time slope movement around various locations at the West Elk Mine. The letter was provided to offer the Division more detail about the emergency work. However, the letter made no mention of the use of or quantities of subsoil material utilized. 6