Report on Early Strength Performance of Modern Day Weak Rock Mass Shotcrete Mixes

Details

• Personal Author:
  Clark, Curtis C. ; Martin LA ; Seymour, Joseph B. ; Stepan MA
• Description:
  The National Institute for Occupational Safety and Health (NIOSH), Ground Control Engineering Branch is investigating the use of shotcrete in weak rock mass mines with the objective of reducing fatalities and injuries resulting from rock fall accidents. When shotcrete is used as part of a multi-element ground support system there is a need to know when the material has developed a threshold early compressive strength of approximately 1 MPa (145 psi) for safe re-entry of miner and machine into shotcreted mine workings. This equates to the material having developed enough strength to be self-supporting and allow for emplacement of the remaining support elements that require drilling of the shotcrete layer without degradation. NIOSH researchers have developed methods and portable test equipment to measure shotcrete strength on-site in the first six hours after application using the ASTM C 116-90 (1990) standard. These advances were demonstrated in tests on five commercially available shotcrete mixes, sprayed as dry shotcrete using the field expedient methods and equipment. The strength values from these tests allowed for real-time identification of the early strength threshold and were consistent with strengths reported using laboratory-type equipment. The findings of this NIOSH research for determining shotcrete early strength can improve mine safety by providing a method for determining initial site specific material property values to be used for design and as a means to conduct on-site quality control and monitoring during production. [Description provided by NIOSH]
• Subjects:
  Accident Prevention Accidents Adhesives Coal Coal Mining Environmental Monitoring Mining Occupational Health Safety
• Keywords:
  Accident-prevention Adhesive-bonding Cements Coal-mining Exposure-assessment Exposure-levels Exposure-methods Injury-prevention Mine-workers Mining-industry Rock-falls Rock-mechanics Statistical-analysis Underground-mining

  More +
• Series:
  Mining Publications
• Publisher:
  Society for Mining, Metallurgy, and Exploration, Inc.
• Document Type:
  Text
• Genre:
  Proceedings
• Place as Subject:
  Arizona ; OSHA Region 3 ; OSHA Region 9 ; Pennsylvania
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  OMSHR - Office of Mine Safety and Health Research
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1-6
• NIOSHTIC Number:
  nn:20036557
• Citation:
  2010 SME Annual Meeting and Exhibit, February 28 - March 3, Phoenix, Arizona, Preprint 10-138. Littleton, CO: Society for Mining, Metallurgy, and Exploration, Inc., 2010 Feb; :1-6
• Federal Fiscal Year:
  2010
• NORA Priority Area:
  Mining
• Peer Reviewed:
  False
• Source Full Name:
  2010 SME Annual Meeting and Exhibit, February 28 - March 3, Phoenix, Arizona, Preprint 10-138
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:291e70c984101d4cf2dd7666815193214f905b79564cc60692a2d91996dba9ccb758cc7ad0d1d9d47d77f6b2d0560abf9b58f55d904feaee95f0aded19dba1cf
• Download URL:
  https://stacks.cdc.gov/view/cdc/227190/cdc_227190_DS1.pdf
• File Type:
  [PDF - 506.72 KB ]