The work in this topic area is supported by the NIOSH Mining Ground Control program. See the NIOSH Mining Products page for software, guides, training materials or other items related to this topic. |
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Rock Falls Spotlights
Comparative Analysis of Moisture Sensitivity Index Tests for Coal Mine Roof (PDF, 217 KB, 2009) Effects of Specimen Age on the Uniaxial Compressive Strength of Weak Coal Measure Rocks (PDF, 764 KB, 2008) |
Guides
Best Practices to Mitigate Injuries and Fatalities from Rock Falls (PDF, 1971 KB, 2000)
This paper presents an overview of the most significant ground control hazards facing today's mineworkers, as well as best practices to reduce these risks.
A User's Guide for the Bplane, Bstepp, and Bwedge Computer Programs (PDF, 2108 KB, 2007-03)
This user's guide covers the operation of a suite of three computer programs - Bplane, Bstepp, and Bwedge. These programs can be used to evaluate the potential for plane shear, step-path, and wedge failures along the crest of a slope bench. The theoretical basis, application, and operation of these programs are described.
Measurement & analysis
Comparative Analysis of Moisture Sensitivity Index Tests for Coal Mine Roof (PDF, 217 KB, 2009)
This paper describes the work NIOSH has completed in evaluating three moisture-sensitivity index tests on roof rocks from 23 U.S. coal mines.
Effects of Specimen Age on the Uniaxial Compressive Strength of Weak Coal Measure Rocks (PDF, 764 KB, 2008)
This paper presents the results of a NIOSH study to evaluate UCS changes occurring in a broad range of weak coal measure rocks over a one-year time span.
An Evaluation of Microseismic Activity Associated with Major Roof Falls in a Limestone Mine: a Case Study (PDF, 253 KB, 2007)
Roof falls are often preceded by a period of elevated microseismic activity, but not all periods of elevated activity result in a roof fall, nor do all roof falls occur after some amount of elevated activity. The objective of this study is to review periods of elevated microseismic activity and determine whether fracture activity rate can be used to anticipate the initiation of roof falls. The results show that limited success would have been achieved by the microseismic system as a roof fall alarm trigger. However, the trigger would have been successful at warning of the onset of elevated activity, allowing mine employees to respond appropriately.
Failure Characteristics of Roof Falls at an Underground Stone Mine in Southwestern Pennsylvania (PDF, 617 KB, 2001-08)
The location and time of 2,007 microseismic emissions from a limestone mine in southwestern Pennsylvania were compared with the development of mine faces and the characteristics of the mine layout. Based on analyses of these results, the occurrence of roof failure zones appears to be associated with certain characteristics of the mine plan.
Methods for Determining Roof Fall Risk in Underground Mines (PDF, 322 KB, 2007-11)
This paper discusses a method to determine the roof fall risk using a qualitative risk analysis technique.
Engineering controls
Design of Primary Roof Support Systems in U.S. Coal Mines Based on the Analysis of Roof Fall Rates (PDF, 588 KB, 2001-06)
A study is described where information was collected at 37 coal mine on roof falls, and other geotechnical, mining, geologic and roof bolting factors. A statistical analysis was conducted on the data with the roof fall rate being the outcome variable.
Evaluating Techniques for Monitoring Rock Falls and Slope Stability (PDF, 3017 KB, 2002)
Several remote-sensing technologies are being evaluated as tools to monitor slopes for hazards and to assess slope stability.
Ideas to Reduce Roof Fall Injuries (HTM, 1997)
A range of ideas to deal with reducing roof fall injuries from miners, mining safety professionals, and NIOSH research.
Personal Bolter Screen: Surface Control to Protect Underground Workers in Coal Mines (PDF, 297 KB, 2003-08)
The Personal Bolter Screen is simply standard wire mesh, produced in approximately 5-ft square sheets. The small sheets provide much of the same protection as traditional 13-16 ft wide wire mesh, but are much easier to handle, store, and install. The results of the trials conducted underground have been extremely positive.
Roof Screening for Underground Coal Mines: Recent Developments (PDF, 1421 KB, 2007)
This paper describes some successful techniques and machine modifications that were evaluated for ergonomic considerations and are being used in productive mines to assist with roof screen installation.
Roof Screening for Underground Coal Mines: Recent Developments (PDF, 247 KB, 2008-06)
This paper discusses roof screen and its potential to prevent hundreds of injuries caused by the fall of small rocks between permanent roof supports.
Administrative controls
How to Prevent People from Going Under Unsupported Roof (HTM, 2002)
Ground fall accidents have been the leading cause of fatalities in the underground coal mining industry for many years. Statistics from MSHA indicate that approximately one-quarter of the victims of these fatal accidents were in an area where no devices had been installed to support the mine's roof.
Technique to Assess Hazards in Underground Stone Mines: the Roof Fall Risk Index (RFRI) (PDF, 2535 KB, 2007)
A roof-fall hazard-assessment technique was developed based on engineering judgment acquired from extensive underground stone mine experience and on examination of the related literature. This technique utilizes observational processes to determine roof fall likelihood. Case-study scenarios offer a realistic picture of model implementation.
Equipment
Roof Hazard Alert Devices (HTM, 2001-06)
Miners have been known to unknowingly venture beyond the last row of roof bolts in underground coal mines. To help discourage miners from going under unsupported mine roof, NIOSH researchers have developed two flashing light roof hazard alert devices that direct a miners attention to a written message, warning the miner to avoid the hazard beyond the device.
Training exercises
Bulls Double Header: Too Much Unsupported Roof
Pete's Predicament: Unsupported Roof
Roof Fall Entrapment: Eyewitness Account by Dave Garry
Dave, a miner helper, tells about witnessing a roof fall that covered a continuous mining machine. He discusses efforts that were made inby supports to rescue the trapped, but unharmed operator and recognizes that danger could have been minimized by installing temporary supports before continuing rescue.
Roof Fall Entrapment: Eyewitness Account by Dave Murone
Dave tells about the experience of having to recover the body of a friend who was killed by a roof fall. The individual who was killed was inby supports at the time of the accident. Dave speculates on why his friend was under unsupported top and discusses the effect that witnessing this accident had on him.
Roof Fall Entrapment: Eyewitness Account by Larry Strayer
This video consists of an interview with a miner who tells about a fall that occurred while he and another miner were attempting to bar down top just inby the last row of supports.
Roof Support in a Primary Escapeway
Videos
Make it Safer with Roof Screen
Using extensive underground footage, this7-minute video shows how well screens keep loose rock from falling in difficult roof conditions. Techniques for installing screens for both outside-controlled and walk-through roof bolting machines are shown. The video also provides safe handling tips, best practices, and information about machine technology that can greatly improve material handling.
Rock Falls - Preventing Rock Fall Injuries in Underground Mines
This video teaches the importance of proper roof scaling in underground mining to avoid injury and improve work conditions.
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