Microseismic Monitoring and Analysis of Induced Seismicity Source Mechanisms in a Retreating Room and Pillar Coal Mine in the Eastern United States

Details

• Personal Author:
  Conrad WJ ; Ghaychi Afrouz S ; Leake MR ; Molka RJ ; Westman EC
• Description:
  A microseismic monitoring system was installed in an underground room and pillar coal mine in the Eastern United States to analyze the occurrence and characteristics of induced seismicity during the retreat of two panels in the mine. This study is the first microseismic monitoring effort at an underground coal mine in nearly 30 years. During the retreat of the first panel, an array of eight uniaxial geophones, installed 10 ft. into the roof, recorded events and their magnitudes. The second panel was monitored using an array of twelve uniaxial geophones and two triaxial geophones, also installed 10 ft. into the roof. Comparing the results of these studies, it has been found that the magnitude of seismic events is minimally affected by immediate roof geology or depth of cover. However, it was observed in both studies that the rate at which seismic events occurred did vary with changing roof geology and depth of cover. Using the seismic data from the second panel retreat, focal mechanism solutions were generated for 50 hand-picked events in order to determine if the failure was in compression, tension, or shear. Results of the focal mechanism solutions show that stress relief resulting in dilational events occurs at significant depths, 150-200 m in this case, beneath the active mining face. [Description provided by NIOSH]
• Subjects:
  Coal Coal Mining Mining Occupational Health Safety
• Keywords:
  Author Keywords: Deep Mining Coal Mining Geotechnical Engineering Ground Monitoring Ground Subsidence Induced Seismicity Retreat Mining Rock Mechanics Room And Pillar Mining Source Mechanisms Subsidence Underground Mines

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• ISSN:
  2467-9674
• Document Type:
  Text
• Funding:
  Contract
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  115-124
• Volume:
  2
• Issue:
  2
• NIOSHTIC Number:
  nn:20068845
• Citation:
  Undergr Space 2017 Jun; 2(2):115-124
• Contact Point Address:
  Erik C. Westman, Mining and Minerals Engineering Department, Virginia Polytechnic Institute and State University, 445 Old Turner Street, 100 Holden Hall, Blacksburg, VA 24060, USA
• Email:
  ewestman@vt.edu
• Federal Fiscal Year:
  2017
• Performing Organization:
  Virginia Polytechnic Institute & State University
• Peer Reviewed:
  True
• Start Date:
  20110816
• Source Full Name:
  Underground Space
• End Date:
  20160815
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:527450f0fec9b49fdb360d733d1579af7664ae05b6e01512dfaec484235648cb65550a27bc5ee703ef22b642963be10701f22059e6d530423e3269c3f9f94a46
• Download URL:
  https://stacks.cdc.gov/view/cdc/207419/cdc_207419_DS1.pdf
• File Type:
  [PDF - 1.80 MB ]