Results 11 - 20 of 48

• Detecting Strata Fracturing and Roof Failures from a Borehole Based Microseismic System
  7/1/2008 - Conference papers
  This paper describes a case study where a surface-based microseismic system, using triaxial geophones in boreholes drilled from the surface, was deployed at a large limestone mine.
• A Case Study Examination of Two Blast Rounds at a Nevada Gold Mine
  1/1/2008 - Conference papers
  NIOSH researchers collected basic data from two blast rounds at the SSX-Steer Mine as a component of a larger study on controlled blasting, the goal of which is to reduce injuries from falling rocks in underground mines.
• An Evaluation of Microseismic Activity Associated with Major Roof Falls in a Limestone Mine: a Case Study
  2/1/2007 - Conference papers
  The goal of this study was to review periods of elevated microseismic activity and determine whether fracture activity rate can be used to anticipate roof falls. The results showed that limited success would be achieved by such a system.
• Load Capacity and Stiffness Characteristics of Screen Materials Used for Surface Control in Underground Coal Mines
  8/1/2006 - Conference papers
  NIOSH conducted an evaluation of screen materials commonly used in U.S. coal mines to determine their support characteristics and identify the parameters that could affect their performance with respect to controlling the fall of rock from the roof.
• Identifying Moisture Sensitive Roof Rocks in Coal Mines
  8/1/2006 - Conference papers
  NIOSH conducted wet/dry immersion cycling of clay-rich rocks, which provides an accurate, quick and inexpensive method for estimating the moisture sensitivity of mudrocks. With this information mine operators can begin to anticipate hazardous ground.
• Field Verification of the Roof Fall Risk Index: a Method to Assess Strata Conditions
  8/1/2006 - Conference papers
  The Roof Fall Risk Index helps the underground stone mine operator to assess defects of the mine strata and rate the relative roof fall risk these defects pose. This paper shows how the defect information is collected and methods to analyze the data.
• Assessing Roof Fall Hazards for Underground Stone Mines: A Proposed Methodology
  3/27/2006 - Conference papers
  A methodology to assess the risk for a roof fall is proposed in a preliminary fashion based on engineering judgment acquired from extensive underground stone mine experience and examination of related literature.
• Forecasting Roof Falls with Monitoring Technologies - A Look at the Moonee Colliery Experience
  8/1/2005 - Conference papers
  Monitoring technology and techniques can provide a means to warn of hazardous roof fall conditions. Measuring roof deflection is the most common method of detecting roof instabilities.
• Assessment of Ground Conditions Near a Mine Portal Using Ground Penetrating Radar
  8/1/2005 - Conference papers
  The objective of this work was to determine if GPR could be used to help assess the mine roof conditions near the No. 4 Portal area of the NIOSH Lake Lynn Experimental Mine (LLEM).
• Characteristics of Mining-Induced Seismicity Associated with Roof Falls and Roof Caving Events
  6/1/2005 - Conference papers
  This study used microseismic emissions to help identify three local rock failure processes. It was also shown that analysis of microseismic emissions can aid in assessing the degree of instability associated with these local rock failure processes.