Original publication date: March 2017
How Do Mine Workers Search for and Find Worksite Hazards?
by Brianna M. Eiter, Jennica Bellanca, William Helfrich, and Timothy Orr
Researchers at NIOSH are studying how SSG mine workers search for and find hazards in their work environment. In this article, we discuss the background of the study participants, give a description of the Virtual Immersion Simulation Laboratory (VISLab) where the study took place, and describe our hazard recognition data collection methods. We also summarize the results of the hazard recognition accuracy data and provide suggestions for how to address hazards most often missed during the study.
Hazard Recognition Task Participants
To identify differences in hazard recognition abilities among a range of participants, we asked new and experienced mine workers as well as mine safety professionals to take part in the study. Eleven new mine workers (less than two years of experience), 11 experienced mine workers (more than two years of experience), and 13 safety professionals (more than two years of experience in environmental, health, and safety positions) participated in the study.
Virtual Immersion Simulation Laboratory (VISLab)
Study participants were invited to the VISLab—a state-of-the-art virtual reality laboratory located at a NIOSH research facility near Pittsburgh, PA. The VISLab has two data collection spaces; one space features a 360° cylindrical screen 10 feet tall and 33 feet in diameter, and the other houses a 26 feet wide by 10 feet tall screen with a 50° curve.
During this hazard recognition task, participants were able to move around the 360° screen area (Room A) while searching the true-size 2D panoramic images. Participant’s eye movements were monitored using SMI Eye-tracking Glasses. The Eye-tracking Glasses are lightweight and record to a small, laptop carried in a backpack. The participant also held a button that he was asked to press to identify a hazard. Eye movements, along with button presses, were recorded to determine whether a participant accurately identified a hazard.
After searching all of the panoramic images, mine workers moved to Room B for debriefing of the hazard recognition task. During the debrief, mine workers were given feedback on where they looked and which hazards they identified and missed.
Hazard Recognition Accuracy Results
For the purposes of this article, we are focusing on hazard recognition accuracy, which is reported as the percentage of hazards that mine workers accurately identified while searching the panoramic images. The recorded eye movements were used to identify differences in how experienced mine workers and safety professionals searched for hazards compared to new mine workers. Overall, safety professionals accurately identified the greatest number of hazards. They accurately identified 61 percent of hazards compared to the experienced mine workers, who identified 57 percent, and new mine workers, who identified 53 percent.
Looking more closely at the hazard recognition accuracy data, Figure 4 shows differences in how participants with different levels of experience performed for each of the image locations. Accuracy in relation to the pit was approximately the same for all groups – participants identified approximately 54 percent of the hazards. The majority of the hazards in the pit were related to powered haulage and ground control issues (e.g., cracks and sloughing of the highwall, missing catch berms, etc.). However, accuracy in relation to the other three image locations did show differences based on experience. Safety professionals outperformed experienced and new mine workers by at least 10% for both plant and roadway images. This difference is likely due to safety professionals’ ability to more accurately identify hazards related to electricity (e.g., open electrical boxes and downed electrical wires) and handling material (e.g., mine workers using inappropriate lifting postures) in plant images, and hazards related to fire (e.g., missing fire extinguishers) and powered haulage (e.g., a smaller vehicle operating in a larger vehicle’s blind spot) in roadway images. Interestingly, experienced mine workers outperformed both safety professionals and new mine workers when viewing images of the shop. Overall, they accurately identified more hazards related to machinery (e.g., using appropriate PPE when operating power tools) and slips, trips, and falls (e.g., material in the walkway).
During debriefing, NIOSH researchers spent time with all participants discussing the hazards that were and were not identified. It is worth mentioning that safety professionals were more likely to identify ground control concerns as additional hazards beyond what was originally identified by NIOSH researchers. Safety professionals identified inadequate or missing berms to a greater extent than both new and experienced mine workers. They were also more likely to identify inadequate guards (e.g., guards made of inappropriate material such as plywood, and guards that are loose or improperly affixed at various locations along the beltline) and inadequate or missing barriers (e.g., issues related to conveyor counterweights found around the plant).
NIOSH Results Summary and Suggestions
Overall, safety professionals identified a greater number of hazards than both experienced and new mine workers. Regardless of experience level and image location, participants were able to identify hazards related to missing PPE (e.g., not wearing a hard hat or safety glasses, using an improvised work surface, not wearing fall protection, not wearing hearing protection). There were revealing differences, however, in the hazards that safety professionals were able to identify compared to new and experienced mine workers. Safety professionals identified a greater number of hazards categorized as overexertion (e.g., improper lifting and moving techniques). They also more accurately identified electrical and fire hazards. In fact, there was at least a 20% difference in accuracy level for both of these hazard types. It is important to note that the safety professional accuracy cannot be attributed to greater experience alone, in that safety professionals and experienced mine workers both had approximately 10 years of experience on average. The differences are likely attributable to their varied skill set, work history, and training.
These findings underscore that it is critical to improve hazard recognition accuracy for both new and experienced mine workers. As an example, one step that can be taken during a pre-shift safety meeting or toolbox talk is to encourage all mine workers to discuss both typical and atypical hazards found at their work locations. During our debrief, several new mine workers indicated that during New Miner training, the majority of the content related to electrical hazards focused on arc flashes, which is a critical hazard but also an atypical hazard. Not surprisingly, in our hazard recognition study, new mine workers were unable to identify the electrical hazards that are more likely to occur at a mine site (e.g., an electrical box left open). As this example demonstrates, it is important to discuss both atypical hazards (arc flashes) and typical hazards (open electrical boxes).
Discussing both typical and atypical hazards is also a helpful reminder for those who spend a majority of their time in a particular location (e.g., the shop), and a learning tool for those who work intermittently at a location. For instance, front end loader and haul truck operators can be encouraged to discuss potential dangers of working too close to the highwall. This is a typical hazard and a critical issue to be aware of when working in the pit, but something that may not be obvious to a general laborer who spends the majority of his or her time performing maintenance around the plant.
Finally, it is important to recognize that hazard recognition training is not “one size fits all.” Each mine site and each work location at a mine site has its own specific hazards. It is important to highlight those site-specific hazards that are critical for mine workers to know and understand. For example, make sure mine workers are knowledgeable of potential precursors of highwall falls or rockslides, such as cracks or sloughing. This will help them find and potentially fix problems before they happen.
Disclaimer: The findings and conclusions in this article are those of the authors and do not necessarily represent the views of NIOSH.