The Influence of Depositional Environment on Dynamic Failure Potential in U.S. Coal Seams

Details

• Personal Author:
  Hanson D ; Lawson H
• Description:
  Dynamic failures in underground coal mines can be defined as the violent ejection of coal, rock and debris into the working area of a mine. These events occur suddenly and often without warning. As such, miners often do not have the opportunity to move to safety before an event. Much research has been aimed at identifying risk factors that contribute to dynamic failure events and the development of appropriate mitigative practices. However, identifying similarities in coal lithotypes and associated host rock lithologies that occur in dynamic failure-prone coals has not been directly addressed. Recent research points to compositional similarities in U.S. coals that have experienced dynamic failure suggesting a set of shared depositional conditions that may be used as a predictive framework for assessing known stratigraphic risk factors. This study seeks to concisely identify this set of depositional conditions to improve dynamic failure hazard forecasting. Improved hazard forecasting will facilitate a reduction in rates of associated injury and fatality. The results from this study indicate that depositional conditions that result in dynamic failure-prone coals in U.S. deposits include: 1. An inland depositional setting, more likely to include massive channel sandstones in the immediate or near-immediate overburden, 2. Peat formation in settings with lower tree density, which may result in dull, non-banded coals with blocky textures, capable of retaining significant amounts of energy prior to kinetic release through violent plastic deformation, 3. Isolation from marine inundation both during and immediately post-deposition, 4. Peat formation under ombrotrophic, freshwater conditions, and 5. Lack of significant sediment influx at the time of deposition. Differences in composition and texture of coal arising from different depositional settings may produce regions more prone to fail dynamically under load, where these differences may be attributed to the nature of the originating vegetative debris and chemistry of the peat mire. Alternatively, inland, freshwater depositional conditions and isolation from marine inundation suggest that the coal overburden may be sandstone-rich and have greater prevalence of paleochannels in the immediate roof lithology, which may result in poor caving behind the working face, high abutment stresses, greater friction at bedding interfaces and unfavorable localized stress concentrations. These possibilities may coexist such that the resultant inherent risk is produced by both coal more capable of violent plastic deformation as well as unfavorable sedimentary settings. Implementation of these concepts into engineering design models is required to address these issues and to provide insight into the root causes behind the observed correlation of dynamic failure-prone coals with the identified depositional conditions. [Description provided by NIOSH]
• Subjects:
  Coal Coal Mining Mining Occupational Health Safety
• Keywords:
  Author Keywords: Coal Bounce Bump Burst Coal Mining Dynamic Failure Environmental Stress Failure Analysis Rock Mechanics Structural Failure Underground Mines

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• Series:
  Mining Publications
• Publisher:
  Society for Mining, Metallurgy and Exploration (SME)
• Document Type:
  Text
• Genre:
  Proceedings
• Place as Subject:
  Colorado ; OSHA Region 10 ; OSHA Region 8 ; Washington
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  SMRD - Spokane Mining Research Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1-10
• NIOSHTIC Number:
  nn:20063504
• Citation:
  MineXchange: 2021 SME Annual Conference and Expo and CMA 123rd National Western Mining Conference, March 1-5, 2021, virtual event, preprint 21-024. Englewood, CO: Society for Mining, Metallurgy & Exploration, 2021 Mar; :1-10
• Federal Fiscal Year:
  2021
• Peer Reviewed:
  False
• Source Full Name:
  MineXchange: 2021 SME Annual Conference and Expo and CMA 123rd National Western Mining Conference, March 1-5, 2021, virtual event, preprint 21-024
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:ace444d34846da9963f3a00ef1b6ed710396aa1c34471eb7082b8bee0c0e97719d5810634bafa1d581415807d8564e19023b40a0351f2839631cc4e04b434bcd
• Download URL:
  https://stacks.cdc.gov/view/cdc/215406/cdc_215406_DS1.pdf
• File Type:
  [PDF - 1.01 MB ]