Results 161 - 170 of 224

• Pumpable Roof Supports: Developing Design Criteria by Measurement of the Ground Reaction Curve
  8/1/2003 - Conference papers
  Pumpable roof supports provide an alternative longwall tailgate roof support and have grown in usage recently. Despite the success of these supports, questions remain regarding critical design issues for optimizing the use of this technology.
• The Long-term Performance of Surface Support Liners for Ground Control in an Underground Limestone Mine
  8/1/2003 - Conference papers
  The purpose of this paper is to evaluate the preliminary findings of a long-term underground study of various types of surface support liners, and to examine installation practices that are critical for an effective liner material application.
• New Tools for Roof Support Evaluation and Design
  8/1/2003 - Conference papers
  This paper describes two tools NIOSH developed. The miniature data acquisition system (MIDAS) could make geotechnical instruments in underground mines more feasible. The rock strain strip, together with MIDAS, more accurately measures rock movement.
• Shear Origin of Tension in Excavation-Induced Fractures
  6/1/2003 - Conference papers
  The authors hypothesize that excavation-induced extension fractures are caused by elastic shearing displacement that in turn causes tension oblique to a propagating shear zone.
• Longwall Tailgates: The Technology for Roof Support Has Improved, but Optimization is Still Not There
  6/1/2003 - Conference papers
  The primary objective of the paper will be to discuss strata mechanics and ways in which the support and strata interaction can be evaluated to provide an optimized secondary support design, particularly standing support systems, for longwall tailgates.
• Technology News 504 - NIOSH Releases New AHSEM and ARBS Software Programs to Improve Ground Control
  4/1/2003 - Technology News
  The AHSEM computer program contains two modules to improve mine layouts for control of horizontal stress. ARBS is designed to help with selecting the proper roof bolt system from the great variety of available bolt types and patterns.
• Best Practices and Bolting Machine Innovations for Roof Screening
  2/1/2003 - Conference papers, Safety guidelines, tips, and checklists
  Injury data show a dramatic reduction in roof skin injuries when screening is used. Five case studies in which roof screen was used are presented along with the costs of materials, impact on bolting advance rates, and potential ergonomic risks.
• Stability of Underground Openings Adjacent to the Sink Hole at the NIOSH Lake Lynn Research Laboratory
  2/1/2003 - Conference papers
  This paper discusses roof monitoring, roof movement, the large roof fall, propagation of roof failures, and the recent support measures to stabilize the escapeway over a portion of the older limestone mine workings at the NIOSH Lake Lynn Laboratory.
• Roof Screening: Best Practices and Roof Bolting Machines
  8/1/2002 - Conference papers, Safety guidelines, tips, and checklists
  Roof screening has been found to be very effective in controlling the fall of small rocks from the immediate roof surface. Data is presented from two mines that show a dramatic reduction in roof skin injuries when screening is used.
• The Introduction of Roof Bolting to U.S. Underground Coal Mines (1948-1960): A Cautionary Tale
  8/1/2002 - Conference papers
  The story of how roof bolting was implemented by the mining industry, but took so long to live up to its promise, is a fascinating example of the interaction between economics, technology, regulation, and science. It still has important lessons for today.