PURPOSE:  To reduce mine injuries, work-related musculoskeletal disorders (MSDs), and accidents through studies of roof bolter, continuous miner and load-haul-dump (LHD) machine designs and operator tasks.

RESEARCH SUMMARY:  MSHA injury data from 2000 to 2004 indicates that two of the major sources of injuries in underground mining came from powered machinery and MSDs. For the same reporting period, almost one third of all incidents could be classified as MSD related. Powered machinery comprised almost 42% of the injuries and 62% of the fatalities. Further analysis showed that the two most frequent causes of machinery related accidents were tramming equipment (roof bolters 19% and continuous miners 6%) and jarring and jolting (load-haul- dumps (LHD’s)/scoops and mantrips 14%).

This research consists of four parts: roof bolter appendage speed study, roof bolter operator low back stress analysis, machine tramming study, and jarring/jolting study of (LHD)/scoops & personnel carrier seats. These provide recommendations/interventions for reducing both the underground mine work hazards and MSDs. Mine work hazards and MSDs arise from improperly designed workstations, equipment, and/or work methods. These include machine and human-body appendage impact, operator errors, awkward postures, repetitive and forceful motions, and excessive jarring and jolting.

Vertical and horizontal appendage speeds for a roof bolter are evaluated and recommendations for machine design modifications and job-task procedural changes that maximize the operator’s chances of escaping injury from contacting a moving boom arm are provided. Initial analysis of low back stress experienced by roof bolter operators showed that an operator’s standing posture, compared to a kneeling posture, significantly increases the forward bending moment, compression force and trunk muscle activity. Also, the kneeling postures in a 45-inch seam height, compared to a 60-inch seam height, increase the same muscle activity significantly for lateral movements and torso extension. Using computer models and operator job task analysis, a risk assessment methodology, detailing the relative risk from each of the environmental hazards that affect their safety, is being developed for face equipment workers. For seated workers in LHD/scoops and personnel carriers vibration studies will be conducted to recommending engineering controls and/or ergonomic interventions for reducing the jarring/jolting related injuries.