The Borehole Monitoring Experiment: Field Measurements of Reservoir Conditions and Responses in Longwall Panel Overburden During Active Mining

Details

• Personal Author:
  Garcia, Fred ; Goodman, Gerrit V. R. ; Karacan, C. Özgen ; Mainiero, Richard J. ; Schatzel, Steven J.
• Description:
  In order to better understand the effects of longwall mining on the methane reservoir overlying the panel, the National Institute for Occupational Safety and Health/Pittsburgh Research Laboratory (NIOSH/PRL) designed and implemented a vertical borehole monitoring experiment (BME) on an active longwall panel. The mine operates in the Pittsburgh Coalbed in Greene County. Pennsylvania. The BME site was located away from either end of the panel to avoid mechanical influences caused by the draping of overburden in this region and was positioned at the same distance from the tailgate gateroad as the mine's gob gas venthole sites. The borehole drilling depths and monitoring intervals were chosen to address a different stratigraphic zone in each of the three planned holes. The monitoring boreholes were positioned perpendicular to face advance using a close spacing pattern of about 15 m (50 ft) between collars. Boreholes were instrumented downhole and on the surface for various measurements. It was observed from the field data that the gob gas venthole fracture network formed 24-46 m (80-150 ft) ahead of the mining face. Overburden permeability's within the same test zones increased 100 to 500 times following undermining. The borehole test interval within the fractured rock responded to overburden gas pressure while the test interval in the caved zone responded to mine ventilation conditions. Eight months after the boreholes were undermined, slug testing indicated permeabilities had increased further in the fractured rock zone. Measurements of surface movement indicate that the permeability development observed in the boreholes is a product of vertical subsidence without lateral movement within the tensional rock mechanics zone on a supercritical longwall panel. Results from this study suggest that maximum permeability in the longwall panel overburden is achieved 58 to 190 m (190 to 620 ft) behind the longwall following maximum compaction of the overburden. PowerPoint and MP3 files are available. Description provided by NIOSH
• Subjects:
  • Copper
  • Metal Workers
  • Metals
  • Mining
  • Occupational Health
  • Safety
• Keywords:
  • Mining-industry; Underground-mining; Coal-mining; Longwall-mining; Methane-control; Methane-drainage; Methanes
• Series:
  Mining Publications
• ISBN:
  9780615200095
• Publisher:
  University of Nevada - Reno
• Document Type:
  Text
• Editor:
  Wallace, K. G. Jr.
• Genre:
  Proceedings
• Place as Subject:
  Nevada ; OSHA Region 3 ; OSHA Region 9 ; Pennsylvania
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  PRL - Pittsburgh Research Laboratory
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  18 pdf pages
• NIOSHTIC Number:
  nn:20034033
• Citation:
  Proceedings of the 12th U.S./North American Mine Ventilation Symposium, Reno, Nevada, June 9-11, 2008. Wallace KG Jr., ed., Reno, NV: University of Nevada - Reno, 2008 Jun; :93-101
• CAS Registry Number:
  • Methane (CAS RN 74-82-8)
• Editor(s):
  Wallace, K. G. Jr.
• Federal Fiscal Year:
  2008
• NORA Priority Area:
  Mining
• Peer Reviewed:
  False
• Source Full Name:
  Proceedings of the 12th U.S./North American Mine Ventilation Symposium, Reno, Nevada, June 9-11, 2008
• Download URL:
  https://stacks.cdc.gov/view/cdc/236576/cdc_236576_DS1.pdf
• File Type:
  [PDF - 52.05 MB]
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:3fbd0fa6b4dd61e3e4c814990f6650151a2a566c7117dd010068a425b3ab8c4436acc8254badc8e396e81a5262cab4bdf1f981c47f06b90dc3d1b600e5e2d353