Results 11 - 19 of 19

• A Retrospective Assessment of Longwall Roof Support with a Focus on Challenging Accepted Roof Support Concepts and Design Premises
  8/1/2006 - Conference papers
  This paper explores the history of longwall shield design over the past 25 years. It also addresses questions such as whether two-legged designs are better than four-legged shields and whether setting pressures should be set as high as possible.
• The NIOSH Shield Hydraulics Inspection and Evaluation of Leg Data (Shield) Computer Program
  8/1/2002 - Conference papers
  A high percentage of longwall shields, which provide ground control in mines, operate well below the rated support capacity due to hydraulic malfunctions. NIOSH developed a computer program to identify shields not performing to rated specifications.
• Laboratory Testing To Quantify Dust Entrainment During Shield Advance
  6/1/2001 - Conference papers
  A series of controlled laboratory tests were conducted in a test stand simulating shield dust entrainment to evaluate changes in airborne respirable dust levels at different air velocities.
• Design Considerations for the Next Generation of Longwall Shields
  6/1/2001 - Conference papers
  The purpose of this paper is to set goals for the future generations of longwall shields.
• Laboratory Evaluation of Shield Dust Entrainment in High-Velocity Airstreams
  2/1/2001 - Conference papers
  Laboratory test to simulate dust liberation during shield movement were conducted.
• Performance and Safety Considerations of Hydraulic Support Systems
  8/1/1998 - Conference papers
  This paper examines the operating principles of hydraulic cylinders and discusses issues pertaining to setting loads, support stiffness, yielding behavior, errors in assessing support loading, and hydraulic failure mechanisms and how to detect them.
• Longwall Retreat of Gate Road Pillars
  1/1/1993 - Reports of Investigations
  This report investigates the removal of gate road chain pillars in conjunction with longwall retreat mining. The objective was to determine how the pillars, supplemental support, and entries were affected by the longwall abutment pressure.
• Examination of Design and Operation Practices for Longwall Shields
  1/1/1992 - Information Circulars
  This report examines shield design, operation practices, and the consequences for using high-capacity shield support systems. An optimization goal is to minimize support loading by using an active shield setting force compatible with strata behavior.
• Canopy and Base Load Distribution on a Longwall Shield
  1/1/1992 - Reports of Investigations
  Roof and floor contact pressure provided by the interaction of a shield with the surrounding strata are examined. Controlled forces were applied to an 800-ton two-leg shield using a mine roof simulator.