Results 341 - 350 of 646

• Hydraulic Prestressing Units: An Innovation in Roof Support Technology
  8/1/2004 - Conference papers
  A new generation of hydraulic mine support prestressing devices has been developed. This paper examines the performance capabilities of these inflatable prestressing units and the impact they have on the performance of various support systems.
• 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.
• Damage Delineation in Structures Using Laser Vibrometry and Remote Excitation
  6/1/2004 - Conference papers
  As part of a research program to reduce injuries and fatalities in the U.S. mining workforce, NIOSH is investigating the potential use of noncontact vibration measurements to identify hazardous ground fall conditions.
• Origin of Mining-Induced Fractures Through Macroscale Distortion
  6/1/2004 - Conference papers
  NIOSH researchers have identified a pattern of fracture zone development as an explanation for fracture formation around rectangular openings in underground mines. Two computer modeling codes were used to model different aspects of this pattern.
• 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.
• Raising the Bar of Ventilation for Large-Opening Stone Mines
  5/1/2004 - Conference papers
  Describes the results of a case study where NIOSH demonstrates that significant increases in total mine airflow can be achieved and the ventilation improved in a large-opening stone mine by replacing an axial-vane mine fan with two 12-ft diameter propel...
• Real-time Neural Network Application to Mine Fire - Nuisance Emissions Discrimination
  5/1/2004 - Conference papers
  Discusses implementation of a real-time neural network which can discriminate mine fires from nuisance diesel emissions as part of an atmospheric mine monitoring system in NIOSH's Safety Research Coal Mine.
• Effects of Far-Field Shearing Deformation on Fracturing Around an Underground Opening
  5/1/2004 - Conference papers
  Researchers are investigating the causes and mechanisms of roof failure in underground mines with the goal that better understanding these issues will lead to better layout and support designs to help prevent fall-of-ground accidents and fatalities.
• Use of a Test Box to Measure Response Times for Machine-Mounted Monitors
  5/1/2004 - Conference papers
  This study describes how response times of machine-mounted methane monitors were measured by placing the methane sensor heads in a specially designed box where they were exposed to an atmosphere containing a constant concentration of methane.
• A Computer Software Program that Estimates Air Quantity Requirements in Large Opening Stone Mines
  5/1/2004 - Conference papers
  Describes a computer program developed by NIOSH for estimating the air quantity needed to dilute diesel particulate matter in underground large opening mines.