Results 81 - 90 of 975

• Case History of the Response of a Longwall Entry Subjected to Concentrated Horizontal Stress
  2/1/2007 - Peer reviewed journal articles
  A study of ground behavior, reinforcement performance and stress redistribution looked at a longwall tailgate under severe horizontal stress. Comparison to field results showed that a FLAC-2D model captured the significant roof and support behavior.
• Arc Flash Awareness
  1/1/2007 - NIOSH/USBM numbered publications, Videos and multimedia
  This video focuses on individual and organizational behavior related to arc flash events over an 11-year period in the mining industry.
• A Measurement Method for Determining Absorption Coefficients for Underground Mines
  12/1/2006 - Conference papers
  This paper presents a method using a ray-tracing technique to determine absorption coefficients for underground mines. Absorption coefficients are determined and presented for octave bands from 63 Hz to 8 kHz.
• Threshold Powers and Delays for Igniting Propane and Butane-Air Mixtures by CW Laser-heated Small Particles
  11/1/2006 - Peer reviewed journal articles
  NIOSH researchers studied laser safety in potentially flammable environments. Researchers measured threshold igniting powers as a function of beam diameter for butane and propane-air mixtures by laser-heating targets placed on optical fiber tips.
• Methane-Air Mixtures Ignited by CW Laser-Heated Targets on Optical Fiber Tips: Comparison of Targets, Optical Fibers, and Ignition Delays
  9/1/2006 - Peer reviewed journal articles
  Researchers conducted experiments to estimate the mean and standard deviation of laser powers needed to ignite 6% methane-air atmospheres using single-mode optical fiber tips covered by two types of iron oxide mixed with a ceramic adhesive.
• Detrimental Effects of Capacitance on High-Resistance-Grounded Mine Distribution Systems
  9/1/2006 - Peer reviewed journal articles
  There are potential detrimental effects of capacitance charging currents during line-to-ground faults in mine power distribution systems. A representative mine power system is modeled, and simulations with faults at various locations are conducted.
• Coal Dust Particle Size Survey of U.S. Mines
  8/1/2006 - Conference papers
  NIOSH and MSHA conducted a joint survey to determine the range of coal particle sizes found in dust samples collected from intake airways of U.S. coal mines.
• Effectiveness of Selected Diesel Particulate Matter Control Technologies for Underground Mining Applications: Isolated Zone Study, 2004
  8/1/2006 - Reports of Investigations
  This study evaluated the effectiveness of the state-of-the-art technologies for controlling DPM and gaseous emissions from underground diesel-powered mining equipment using the isolated zone approach.
• Prediction of Longwall Methane Emissions and the Associated Consequences of Increasing Longwall Face Lengths: A Case Study in the Pittsburgh Coalbed
  6/1/2006 - Conference papers
  NIOSH conducted a study with the goal of characterizing methane emissions from increasing face lengths in the Pittsburgh Coalbed and providing a method of predicting emissions increases from longer faces and of planning for more methane control.
• Predicting Methane Emissions from Longer Longwall Faces by Analysis of Emission Contributors
  6/1/2006 - Conference papers
  NIOSH conducted a longwall methane emission and mining time study at a Pittsburgh Coalbed mine to predict emissions from a longer face, and developed and applied mathematical formulas and constants to characterize four emission contributors.