Dynamic Failure Classification Within the Context of Regional Geology: A Case Study from the Uinta and Piceance Basins

Details

• Personal Author:
  Hanson D ; Lawson H ; Mastalerz M
• Description:
  Dynamic failure may be defined as the violent ejection of coal or rock within a working area of an underground coal mine. Despite evolving mining techniques and practices, dynamic failures continue to occur. Between 1983 and 2013, American coal mines have experienced nearly 400 cases of reportable dynamic failure accidents, resulting in greater than 20 deaths and 155 lost-time accidents. The precise balance of risk factors and specific failure mechanism(s) may vary from case to case. Lack of consistent hazard prediction may come in part from an oversimplification of dynamic failure phenomena because there is not one type of dynamic failure, but rather several types-each having similar but distinct physical characteristics and driving causes. By clearly demarcating the differences between types of dynamic failure events and their associated characteristics and geologic settings, we can begin to more effectively identify patterns in specific risk factors that contribute to them. In response to this need, researchers at the National Institute for Occupational Safety and Health (NIOSH) developed a hierarchical classification decision tree based upon physical characteristics and potential event source(s), as identified through review of the available literature, historical dynamic failure reports, and Mine Safety and Health Administration (MSHA) accident and fatality reports. The classification hierarchy was applied to a database of 39 dynamic failure events from historical reports (pre-1983) and MSHA fatality reports occurring after 1983 in the Uinta and Piceance Basins. This region was chosen to apply the newly developed classification scheme as it accounts for 74% of reportable dynamic failure events occurring between 1983 and 2019. Application of the dynamic failure classification hierarchy to the Uinta and Piceance Basins show several differences between events occurring in the two basins: 1. Failures initiated by the massive collapse of strata are more prevalent in the Uinta Basin. Dynamic failure linked with the massive collapse of strata, such as bounces, air blasts, and shock bursts, may be the result of relatively rapid basin subsidence in conjunction with an inland depositional setting, resulting in thick competent units surrounding the coal. 2. The loss of confinement failure mechanism is prevalent in both the Piceance and Uinta Basins, in association with coal/mudstone contacts at the roof and floor lithologies and may have its origins in frequent transgressive/regressive events associated with the retreat of the Western Cretaceous Seaway. However, the relative prevalence of mid-pillar bursting with no slip in the Uinta Basin may be the result of the frequency of coal/sandstone contacts, which may be a function of the basin's relatively distant position from the shoreline and preponderance of more inland depositional settings. 3. Gas-driven failures in the Piceance Basin correlate to high vitrinite reflectance in the Colorado B seam and suggest that the primary risk in this area derives to a greater extent from thermal maturity of the seam itself than from strata-driven failures, as is the case in Uinta Basin failures. These findings highlight the differences between regionally based risk factors in contrast to risk factors associated with the seam itself. In the Uinta Basin, risk is clearly related to stratigraphic features. In the Piceance Basin, however, risk was dominated by thermal maturity of the Colorado B seam, although other, more localized, stratigraphically influenced risk factors were not insignificant. These geologic dissimilarities resulted in observable differences in dominant modes of dynamic failure between these two regions and have implications toward the application of more targeted risk mitigation practices. Targeted risk mitigation practices can be enacted only once the sources and mechanisms of failure have been identified. [Description provided by NIOSH]
• Subjects:
  Environment Mining Occupational Health Safety
• Keywords:
  Author Keywords: Coal Bump Burst Coal Mines Dynamic Failure Environmental Factors Environmental Stress Failure Analysis Geologic Strata Piceance Rock Mechanics Structural Failure Subsidence Uinta 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 ; Indiana ; OSHA Region 10 ; OSHA Region 5 ; 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:
  1-9
• NIOSHTIC Number:
  nn:20063511
• Citation:
  MineXchange: 2021 SME Annual Conference and Expo and CMA 123rd National Western Mining Conference, March 1-5, 2021, virtual event, preprint 21-025. Englewood, CO: Society for Mining, Metallurgy & Exploration, 2021 Mar; :1-9
• 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 21-025
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:9023ed3653e95be352e11bf2039bcddc72faf1f905be7fd0d0eb5546ff1cd3752e3a08648f7417f1fb7422b847db2668323a3a206be538624ac0090503c62818
• Download URL:
  https://stacks.cdc.gov/view/cdc/215413/cdc_215413_DS1.pdf
• File Type:
  [PDF - 772.07 KB ]