Results 101 - 110 of 151

• Investigation of Pillar-Roof Contact Failure in Northern Appalachian Stone Mine Workings
  8/1/2004 - Conference papers
  Underground limestone mine roofs in Northern Appalachia can be subject to high horizontal stresses. A case study is presented showing that induced stress changes in the immediate roof are less likely if the pillars contain weak bedding planes.
• UDEC Modeling of an Underground Opening in a Rock Mass of Varying Quality
  5/1/2004 - Conference papers
  This paper describes a project involving modeling rock masses with varying Rock Mass Rating (RMR) values to determine the degree of instability that develops around an underground opening as a function of RMR.
• Design Parameters of Roof Support Systems for Pre-Driven Longwall Recovery Rooms
  2/1/2004 - Conference papers
  A calibrated three-dimensional finite element model, developed in conjunction with an underground test area, provided the critical components and design principals for a comprehensive parametric study.
• Reducing the Risk of Ground Falls During Pillar Recovery
  12/1/2003 - Conference papers
  Pillar recovery has been associated with nearly one third of roof fall fatalities in underground coal mines during the past decade. This paper discusses design methods and technologies that have been transferred and implemented in mining.
• 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.
• 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.
• 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.
• 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.