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2.05.6(6) <br />The visual subsidence monitoring program will continue and survey <br />monitoring will be performed quarterly. The results of the survey monitoring <br />will be studied for abrupt changes in surface levels which might indicate <br />mining impact. <br />The Operator will both survey and visually monitor the effectiveness of the <br />ground control methods implemented during development mining through the <br />fault trace. Any failure of the ground support will be immediately reported to <br />the DRMS. The report will include the Operator's remedial roof support plan. <br />Ground support failure is defined as a cave of debris of over one mining <br />height within the fault trace. Mining has been performed through the fault <br />trace with no problems. Therefore no additional monitoring or reporting is <br />required. <br />The operator installed subsidence monuments over the 1 West Mains where <br />they go under Terror Creek and at or near the transmission line towers <br />located immediately north and south of the 1 West Mains. These monuments <br />will be utilized to verify that subsidence does not occur within the limited <br />extraction zone. <br />At this time there are no plans to mine under the Terror Ditch, or to mine <br />under Terror Creek Reservoir. A subsidence monitoring plan will be <br />developed prior to mining, within the angle of draw of the ditch. <br />The B Seam mine plan had gate road entries for the B -8 through B -11 <br />panels under panels D -7, D -8, and D -9. This area of multiple seam mining <br />has an increased risk to damage the land surface through increased tensile <br />strains. It is expected that this increased strain will cause surface fractures <br />to form. Since this area of multiple seam mining underlies Sheep Corral <br />Gulch, the Forest Service is concerned that surface fractures may cause <br />interruption of surface flows (when present), damage stock ponds or create <br />large fractures that will need to be mitigated. Only B -8 an B -9 panels were <br />mined in this area and the panels was cut short by poor mining conditions so <br />significant surface fractures did not materialize. <br />PR-14 2.05-170- 03/14 <br />