Mining is one of the most physically demanding occupations. It is also one of the most dangerous in terms of exposure to ergonomic hazards. Musculoskeletal disorders (MSDs) resulting from repetitive manual work have long been identified as a significant and costly problem for the mining industry. Strain and sprain injuries account for 24.0% and 25.2%, respectively, of all reported injuries for underground coal mining. They account for 19.4% and 20.4%, respectively, of all injuries for underground metal/nonmetal mining. In 2003, the Mine Safety and Health Administration (MSHA) reported that 44% of all illnesses were joint, tendon, or muscle inflammation. Using a new process integration and interventions development approach in mining, NIOSH contributed to a 34% overall reduction in lost workdays due to repetitive-type injuries during 1998-2004. This approach focuses on incorporating the ergonomics process in existing safety and health programs of the mining companies and empowering the workers to proactively develop injury prevention solutions to their tasks.

Although the need for intervention and prevention is great, the underground mine environment poses unique barriers to implementing many standard ergonomic "fixes." The mining workplace is a very dynamic work environment. This dynamic nature requires that workers be made aware of risk factors and take early actions to reduce their injury risk. However, mining companies rarely spend the resources to educate workers on ergonomic interventions despite recent evidence that ergonomic considerations can have significant impact in reducing the risk of both MSDs and traumatic injuries. This impact is documented in other industries that voluntarily implemented interventions despite lack of any established ergonomic regulations, standards, and methodology prescribing how that science should be applied in a workplace.

Recent major accomplishments pertain to (1) whole-body vibration and (2) development of ergonomic processes through partnerships with mines. Previous studies have shown that operators of heavy mobile equipment are afflicted by musculoskeletal injuries of the arms, shoulders, neck, and lower back. From this review, it is shown that whole-body vibration (WBV) and the postural requirements of work (both static and awkward postures) are important risk factors that contribute to MSDs among equipment operators. Despite this, very little research has been done to systematically characterize the exposure to these ergonomic hazards. Quantifying vibration and postural requirements in practical settings is needed for a better understanding of the exposure levels present in different equipment while performing various tasks. Furthermore, it is important to evaluate postural instability caused by exposure to WBV and evaluate the availability of proper egress for preventing falls among operators of mobile equipment. As such, our research evaluates exposure to WBV, awkward posture, postural stability, and improper egress from equipment among operators of mobile equipment.

For an ergonomics process to be accepted and effective, it requires working with mining companies, associations, and regulatory agencies (MSHA and the Occupational Safety and Health Administration (OSHA)) in a holistic approach. Science-based education and interventions have led to a rising awareness among mining companies of the benefits of a proactive process addressing MSD risk factors. For example, successful education of 280 management and labor employees and implementation of a proactive ergonomics program at Bridger Coal Co. have resulted in reduced injuries and more than 22 ergonomic interventions in use at the company’s mine. Using results from the Bridger experience, researchers have been able to educate mines such as Badger Mining, Vulcan Materials, Specialty Minerals, Unimin, and Morton Salt in the importance of the abovementioned new approach, which relies on an employee participation process to implement interventions that promote their health and safety at work. This success has led to the request by many mining companies (e.g., U.S. Borax, U.S. Silica, Consol) and organizations (e.g., Industrial Minerals Association (IMA), National Stone, Sand & Gravel Association (NSSGA), United Mine Workers of America (UMWA)) for similar guidance from NIOSH. Currently, three aggregate companies (Vulcan Materials, Hansen, and Luckstone) and two industrial sand companies (Unimin and Badger Mining), as well as two of the largest mining associations (IMA and NSSGA), have joined our effort to develop methods and education that ensure successful integration of ergonomics into their current safety and health programs.

Although several interventions have been developed in the past, the documentation of their effectiveness and use has not been recorded. A new approach of thorough documentation and measurement of usability and effectiveness is our focus as the programs grows over the next decade. NIOSH is attempting to address the lack of ergonomics education, process implementation, surveillance systems, and science-based interventions in mining. In that effort, a significant investment has been made to grow and focus MSD prevention research within the NIOSH Mining Program during recent years. The new MSD Prevention Team is composed of certified professional ergonomists, industrial and mining engineers, training specialists, physiologists, bioengineers, and engineering technicians. A multidisciplinary approach to bringing safety, health, and productivity is afforded through this diverse team and through cooperation with other Mining Program teams, such as training, machine safety, and electrical safety.

Our MSD prevention research has both field and lab components. Field research determines priority problems through direct observations and physical measurements. The physical requirements of any job are not easily measured in the workplace. Lab experiments provide opportunities to study MSD risk factors in a controlled environment. The results add to the science and knowledge base of ergonomics. Recently, a NIOSH researcher conducted studies that defined the physiological demand of performing lifting tasks while the back is in flexion. This study showed that the angle of flexion has a significant effect on resultant low-back pain and injury. Considering the restricted postures used by miners while doing their jobs, the impact of this study is far-reaching. This research directly relates to the importance of the design of physical tasks performed in mining and has contributed to a preliminary assessment tool designed to determine the prevalence of low-back pain as it relates to typical mining tasks.

Other functions of the lab studies are to simulate mining tasks and equipment, determine physical effort, and test possible interventions for better job and equipment design. For example, NIOSH developed an improved low-seam shuttle car seat that reduces worker exposure to damaging jarring and jolting. The seat is now available from Joy Mining Machinery, the largest equipment manufacturer of shuttle cars, and is being ordered by mining companies for both new and retrofit orders. Researchers examine the effects of the mining environment, workforce age, and equipment and tool design on the jobs performed by mine workers. Currently, experiments on ingress/egress of equipment, scaling bar, and roof bolter screening studies are being done in our state-of-the-art labs. These include three physical capabilities labs (strength, vibration, and motion analysis) and a human performance research mine, which simulates an underground mining environment. These new labs are equipped with current technologies, including telemetric electromyography, an infrared motion analysis system, a lumbar motion monitor, force plates, and goniometers. Major equipment manufacturers (Joy, Jeffrey, and Voest-Alpine), universities (Purdue University, University of Pittsburgh, University of Wisconsin, and University of Cincinnati), and mining associations (IMA, NSSGA, and UMWA) are partners in the studies. Interventions are developed, tested, then taken to the field. This comprehensive methodology allows researchers to prioritize, study, and solve the most pressing and costly health and safety problems in the mining industry. Science-based interventions are then shared with the mining industry. The main goal is to reduce risk factors with a high probability of leading to MSDs and lost work.

Because the team is small compared to the required resources for directly addressing the needs of each mining company, leveraging large mining associations and partnering with mine companies, universities, and government agencies will help to integrate the ergonomics process into their existing health and safety programs. Our proactive approach to reduce risk factors on the job instead of waiting for an injury to occur is catching on fast in the mining industry. In view of the current predominantly older workforce, the mining industry is in a unique position to make use of their experience and knowledge to help design better mining methods, tools, equipment, and processes for a new generation of miners. The intermediate- and long-term impacts of our MSD injury prevention research is expected to be visible and significant. As the costs of MSD injuries continue to rise, reduction of risk factors becomes critical to the effective and efficient use of the mining industry’s most valuable asset - its workforce.