2009-04-13_REPORT - C1996083 (6)

Home Browse Search

Introduction This report is for the period from July 2008 through December 2008. Mine Construction of the Bowie No. 2 Mine began during May of 1997, with coal production beginning during August 1997. The mining permit application for the Bowie No. 2 Mine requires the operator to submit the results of the subsidence monitoring programs and the results of the visual inspections of known modern and historic landslides within the permit and adjacent area for stability in June and December of each year and report these results to the Division within 30 days of the ends of the reporting periods. The operator is also required to inspect these landslides, both modern and historic, monthly for six months immediately after retreat mining occurs. This same inspection routine is applied to any spring or pond in the immediate proximity of retreat mining. Longwall mining during the period included finishing the B-7 panel. The longwall operated in the B-7 Panel starting in July and completing in December. The 2nd East Mains were completed during the period. Development for the B-8 panel was approximately 50% complete by the end on the reporting period. Visual Inspection of known historic and modern landslides. A visual inspection of all known historic and modern landslides was conducted during • November 25, 2008 by Brad Lindsay, Rock Logic Consulting LLC. Mr. Lindsay's report is attached. Fiver new subsidence cracks were noted. Increased Inspection activity associated with retreat mining. Accessible subsidence cracks are repaired during coal exploration events and are monitored by both coal exploration supervisors and hydrologic monitoring technicians. The accessible visual results of the subsidence effects associated with the Bowie No. 2 Mine are overlain on Map 27-C Subsidence Features. Map 27-C is enclosed. During this period, Springs 2, 3, 4, 4A and Pond 4 were impacted or re-impacted by the longwall during the period October through December. Springs 5, 5A, 5B and Pond 5 were impacted or re-impacted by 2nd East Main development during May and June. Potentially impacted or re-impacted means the mine workings or angle of draw of the mine workings passed under the monitoring point during the reporting period. No influence to any hydrologic monitoring points was observed during this period. Results of Subsidence Survey Monitoring The results of the October and December 2008 monitoring are attached. As in the past, the survey was performed by Cragg Surveying using GPS methods. Analysis of Subsidence Data The following table presents an analysis of the subsidence survey data. Panel B-6 was • completed in January and February. Following is a summary of the survey data collected during the period. There was no activity near Hubbard Creek or Dove Gulch. 2