2009-12-03_REVISION - C1996083 (5)

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• 2.05.6(6) The Operator will evaluate each rejuvenated or new landslide to determine what the apparent cause of the modern movement might be. If appropriate, mitigation methods will be proposed to minimize hazard to the mine facilities, public health and safety, and the environment. The visual subsidence monitoring program will continue and survey monitoring will be performed quarterly. The results of the survey monitoring will be studied for abrupt changes in surface levels which might indicate mining impact. The Operator will both survey and visually monitor the effectiveness of the ground control methods implemented during development mining through the fault trace. Any failure of the ground support will be immediately reported to the DRMS. The report will include the Operator's remedial roof support plan. Ground support failure is defined as a cave of debris of over one mining height within the fault trace. Mining has been performed through the fault trace with no problems. Therefore no additional monitoring or reporting is required. The operator will install subsidence monuments over the 1 West Mains where they go under Terror Creek and at or near the transmission line towers located immediately north and south of the 1 West Mains. These monuments will be utilized to verify that subsidence does not occur within the limited, extraction zone.' The B Seam mine plan has gate road entries for the B-8 through B11 panels under panels D-7, D-8, and D-9. This area of multiple seam mining has an increased risk to damage the land surface through increased tensile strains. It is expected that this increased strain will cause surface fractures to form. Since this area of multiple seam mining underlies Sheep Corral Gulch, the Forest Service is concerned that surface fractures may cause interruption of surface flows (when present), damage stock ponds or create large fractures that will need to be mitigated. • TR-65 2.05 - 120 - 12/09