Case Study of Sinkholes over a Nebraska Limestone Mine

Details

• Personal Author:
  Powell LR ; Siekmeier, J. A. ; Triplett TL
• Description:
  The USBM responded to a citizen's request for assistance when five sinkholes, each 20 m to 25 m in diameter, developed within a 90 m by 105 m area on agricultural land overlying an abandoned section of an underground limestone mine. It was determined that the subsiding area could enlarge due to three mechanisms: (1) caving and sliding of soil into the existing sinkholes, (2) new roof falls in the mine adjacent to the existing sinkholes, or (3) new pillar failures in the mine adjacent to the existing sinkholes. The safety of agricultural workers was the main consideration at the site and so it was recommended that a buffer zone be created around the subsiding area based on the mechanism that could cause the greatest sudden increase in the subsiding area. Drilling logs were used to create a geologic model from which a simplified computer simulation of the stress distribution in the rock mass was developed. It was determined that the vertical stress had increased in the pillars near the existing sinkholes during sinkhole formation and that this may have weakened the nearby pillars. These pillars are currently stable, but may eventually deform or fail due to this weakening. Subsequent roof failure would then result in enlargement of the existing sinkholes. Therefore a buffer zone extending 43 m from the edge of the existing sinkholes was recommended. [Description provided by NIOSH]
• Subjects:
  Agriculture Case Reports Environmental Health Mining Occupational Health Safety Safety Management
• Keywords:
  Agricultural-industry Case-studies Environmental-factors Mine-shafts Mining-industry Models Rock-mechanics Safety-monitoring Safety-research Soil-analysis Soil-sampling

  More +
• Series:
  Mining Publications
• Publisher:
  U.S. Bureau of Mines
• Document Type:
  Text
• Genre:
  Proceedings ; Abstract
• Place as Subject:
  District of Columbia ; Minnesota ; OSHA Region 3 ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  TCRC - Twin Cities Research Center
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  46
• NIOSHTIC Number:
  nn:20024921
• Citation:
  Abstract Book, U.S. Department of the Interior Conference on the Environment and Safety, April 24-28, 1995. Washington, DC: U.S. Bureau of Mines, 1995 Apr; :46
• Federal Fiscal Year:
  1995
• Peer Reviewed:
  False
• Source Full Name:
  U.S. Bureau of Mines
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:70d3ff171f05025df3a29f394fe131b8b0421d3da9bf0f6345abd3b101e4dba9ba9859b668fb6d74377850913649e56a81282475232d2d077a7e8387e989ca86
• Download URL:
  https://stacks.cdc.gov/view/cdc/220867/cdc_220867_DS1.pdf
• File Type:
  [PDF - 277.78 KB ]