Development of Numerical Models to Investigate Permeability Changes and Gas Emissions Around Longwall Mining Panels

Details

• Personal Author:
  Esterhuizen, Gabriel S. ; Karacan, C. Özgen
• Description:
  Underground longwall mining of coal causes large-scale disturbance of the surrounding rock mass. The disturbance can increase the rock mass permeability through a reduction on the stress, as well as formation of new fractures in the rock. Methane gas contained in the disturbed rock mass can migrate toward the low-pressure mine workings and present an explosion hazard. This paper describes the application of a finite difference program to develop a geomechanical model that predicts permeability changes within the rock mass. The calculated permeabilities are used as input to a reservoir simulator that models methane desorption from the coal matrix, methane release from the rock layers, and flow toward the mine excavations. The model also considers the basic characteristics of the mine ventilation network. The geomechanical model uses empirical relationships between fracture permeability and stress to calculate permeability changes around a longwall face. The extent of rock failure is determined using a strain-softening model that considers both rock matrix and bedding plane failure. The cave rock (gob) is modeled as a compressible, granulated material. The calculated horizontal and vertical permeabilities around the longwall face are averaged and used as one of the inputs to the reservoir model. The reservoir model was developed and calibrated against records of methane flow at a study mine in southwestern Pennsylvania. Good correlation between actual gas production and model outputs has been achieved. The modeling approach provides a basis for estimating methane inflow and optimizing control measures. [Description provided by NIOSH]
• Subjects:
  Coal Coal Mining Explosions Methane Mining Occupational Health Safety
• Keywords:
  Coal-mining Control-technology Hazards Injuries Longwall-mining Methane-control Methanes Mining-industry Models Safety-research Underground-mining

  More +
• Series:
  Mining Publications
• ISBN:
  9781604234541
• Publisher:
  American Rock Mechanics Association (ARMA)
• Document Type:
  Text
• Genre:
  Proceedings
• Place as Subject:
  Alaska ; OSHA Region 10 ; OSHA Region 3 ; 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:
  1-13
• NIOSHTIC Number:
  nn:20028124
• Citation:
  Alaska Rocks 2005, Proceedings of the 40th U.S. Rock Mechanics Symposium, Anchorage, Alaska, June 25-29, 2005. Alexandria, VA: American Rock Mechanics Association (ARMA), Paper No. ARMA/USRMS 05-744, 2005 Jun; :1-13
• CAS Registry Number:
  Methane (CAS RN 74-82-8)
• Editor(s):
  Chen G; Huang S; Zhou W; Tinucci J
• Federal Fiscal Year:
  2005
• NORA Priority Area:
  Disease and Injury: Traumatic Injuries
• Peer Reviewed:
  False
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:48abe7daeaf39c37685f4fc2379d666279b6b3b059feccbfa95cd510a6102f6fd67069049daeca82d1a71f7f67ffef62c8437c6368d303613842ed16276835b4
• Download URL:
  https://stacks.cdc.gov/view/cdc/221090/cdc_221090_DS1.pdf
• File Type:
  [PDF - 410.42 KB ]