Mining Topic: Proximity Detection
What is the health and safety problem?
Mine workers perform tasks and control machinery in challenging conditions, often in close proximity to moving machines. At surface mines, large equipment often has limited visibility, making it difficult to see smaller vehicles and pedestrians. In underground mines, confined spaces, remote controlled equipment, and limited visibility due to dust, poor lighting, and the machinery itself make proximity a challenge.
A recent increase in accidents involving remote controlled continuous mining machines has brought this issue to the forefront for the Office of Mine Safety and Health Research (OMSHR).
What is the extent of the problem?
More than 40% of the most serious injuries (fatalities and permanent disabilities, 2000–2007) in the mining industry involve accidents classified as struck-by or caught-in machinery and powered haulage equipment. For surface mining, collisions and driving over an unseen edge contributed to 3 to 4 fatalities per year between 2000 and 2007. For underground coal mining, pinning and striking hazards involving continuous mining machines resulted in 35 fatalities since 1984. Striking and pinning accidents involving shuttle cars and scoops underground also resulted in 16 fatalities between 2000 and 2010.
MSHA has proposed new rules that would require proximity detection systems on continuous mining machines. Find out more at MSHA’s Proximity Detection/Collision Warning Single Source Page.
How is OMSHR addressing the problem?
OMSHR has developed specific research goals for preventing injuries involving powered machinery, and proximity detection is currently the primary research focus in this area. Acting as an impartial third party, OMSHR has evaluated commercially available proximity detection systems for both underground and surface mining. Based on these findings, recommendations for testing and implementing systems have been introduced and improvements are being developed.
Surface mining: OMSHR developed new proximity detection systems through research partnerships, including radar-based technology and one of the first GPS-based systems for mining equipment.
Underground mining: OMSHR is developing a prototype intelligent proximity detection system that continuously monitors mine workers’ positions in relation to machines and established safety zones. Specific machine functions are disabled to prevent unsafe movement toward mine worker while allowing functions that do not put the worker at risk to remain operational.
What are the significant findings?
- After extensive field evaluations, OMSHR made recommendations for the evaluation and implementation of proximity detection systems in surface mines.
- OMSHR investigated the standing positions and visual attention locations for continuous mining machine operators, as well as safe operating speeds for mining machines.
- OMSHR has also developed sophisticated mathematical models of the magnetic fields used in proximity detection systems.
Based on these background studies, the Intelligent Proximity Detection (iPD) system was designed to provide situational protection based on the position of a mine worker relative to the machine. The iPD system has been shown to accurately track the position of mine worker and disable potentially hazardous machine motions.
What are the next steps?
NISOH will focus on developing and testing of the iPD system to provide improved protection around continuous mining machines while minimizing false and nuisance alarms.
Noteworthy Publications & Products
- Engineering Considerations and Selection Criteria for Proximity Warning Systems for Mining Operations (2013-11)
A Proximity Warning System (PWS) marker on each worker that is activated as he or she approaches a dangerous area could alert the operator and prevent a potential injury or fatality.
- Operating Speed Assessments of Underground Mining Equipment (2010-03)
This publication details the results of NIOSH studies to examine operating speeds based on usage and seam height.
- Proximity Warning Systems for Mining Equipment (2013-10)
NIOSH OMSHR sponsored a free, one-day workshop to discuss proximity warning and detection systems for mining equipment.
- Recommendations for Evaluating & Implementing Proximity Warning Systems on Surface Mining Equipment (2007-06)
NIOSH studied technology and methods that could reduce accidents involving surface mining equipment. These proximity warning systems included radar, sonar, GPS, radio transceiver tags, and combinations of radar and cameras.