Slips, trips, and falls (STFs) pose a significant burden to the U.S. mining industry leading to both fatal and non-fatal incidents. STFs were the second leading cause, at approximately 22 %, of non-fatal incidents reported to the U.S. Mine Safety and Health Administration (MSHA) from 2015 through 2018 (Mine Safety and Health Administration, 2015–2018). Analyses of mining fatal and non-fatal STF incidents conducted over several decades highlight the need to reduce STF incidents, some over 35 years old (Buck and Coleman, 1985; Nasarwanji and Sun, 2019; Radomsky et al., 2001). A recent analysis of surface stone, sand, and gravel mining operations found that STF incidents occur at a rate of 6.2 per 1000 full-time equivalent employees per year, leading to approximately 23,800 total days lost per year, and having an estimated cost of $17.5 million per year to the U.S. mining industry (Nasarwanji and Sun, 2019). In addition, approximately 10 % of surface mining fatalities are related to STFs (Nasarwanji, 2016).

The importance of reducing STF incidents in the mining industry has been recognized, with several surveillance studies providing insight into the most common activities and equipment associated with non-fatal events. Based on MSHA non-fatal injury data (2015–2018), walking or running (35.4 %) and getting on and off equipment (24 %) were the two main activities at the time of the STF event (Mine Safety and Health Administration, 2015–2018). Non-fatal injuries related to getting on and off equipment have been previously investigated (Moore et al., 2009; Nasarwanji et al., 2018; Pollard et al., 2019; Santos et al., 2010). In comparison, the activities of walking and running have not received as much attention, with only one observational field study investigating STF risk factors on walkways, stairs, and ladders (Nasarwanji et al., 2019). Surfaces commonly used for walking and running at mines include walkways and stairways and hence are the focus of this work. Walkways could include both marked designated paths of travel as well as other surfaces traversed commonly. Falls from stairs and ladders also pose a burden in the mining industry (Nasarwanji and Sun, 2019). Walkways, stairs, and fixed ladders are infrastructure components of mine sites, and ergonomics and safety deficiencies can be addressed through engineering controls. Other research has investigated portable and extension ladder safety (e.g. (Simeonov, 2017),), and were not a focus areas of this research.

Checklists and audits have been designed and applied in multiple industrial sectors to identify human factors and ergonomics issues (Drury and Dempsey, 2012). For the mining industry, ErgoMine is a mobile-device application-based audit tool, developed by researchers from the National Institute for Occupational Safety and Health (NIOSH), to identify ergonomics and safety hazards and provide remedial actions in three types of mining operations (Dempsey et al., 2016). The audits were developed based on previously recommended requirements, including being self-explanatory, observable, repeatable, and solution oriented (Dempsey et al., 2017). The ErgoMine tool provides three primary audit sections—maintenance and repair activities, bagging operations, and haul truck activities. STF hazards are briefly covered in several of the maintenance and repair and haul truck modules of the audit. Since the audits were not developed to specifically address STF hazards, there was a need for more detail to comprehensively address STF hazards in mining environments. The development of the taxonomy described herein was a foundational component of a project designed to more comprehensively address STF hazards in mining.

Previous research studies provided significant insight into some aspects of the task, equipment, and environmental characteristics associated with STF incidents in mining. However, there was a need to systematically identify, categorize, and create a framework of mining system features associated with STFs to facilitate the development of relevant research and practical solutions and tools that allow mine workers to efficiently identify and remediate STF risks. The primary advantage of a taxonomy that identifies STF hazards at surface mining sites is the ability to provide a structured approach to communicating the scope of STF hazards to researchers, safety and health practitioners, and miners. As more systematic research efforts are undertaken, the taxonomy can be expanded to include a sociotechnical systems approach that considers broader factors such as organizational and economic influences.

Due to a lack of tools to help with proactive STF hazard assessment in the mining industry, this paper highlights the development of a STF hazard taxonomy which informed the development of STF hazard identification and remediation audit tools. A taxonomy of STF hazards was developed based on the recommendations by Drury and Dempsey (2012), which indicated that regulations, standards, and guidelines can be an excellent source of information to identify hazards when developing audits and checklists. Both mining-specific and general industry regulations in the U.S. along with common standards and guidelines were used for the taxonomy development to ensure validity of the hazards identified. It was convenient that hazard categories lined up with specific elements or features of the walkway, stairway, and fixed ladder. This allowed each feature, such as the tread or handrail, to be completely evaluated before moving on to the next feature. The same can be said about features like clearances, illumination, and slip resistance.

Some elements such as rungs on ladders, platforms and handrails along stairways, and handrails and floor openings along walkways and elevated walkways, specifically have a lot more detail in the STF hazard taxonomy. This can be due to additional detail provided in the standards, potentially due to the risk associated with those elements or the intricacies of design. Appropriate platforms, handrails, and floor openings are key to prevent falls that have already been shown to pose a fatal risk in the mining industry (Nasarwanji, 2016).

The development of the taxonomy could have been simplified if remedial recommendations were not included; however, the utility of the taxonomy would be limited in this case to hazard identification. In addition, its utility as an audit tool, as in the case of the STF hazard checklists developed for the next iteration of ErgoMine (Nasarwanji et al., 2021), would not have met the requirements set forth by Dempsey et al. (2017) that the audit be solution oriented. Hence, the benefits and utility of generating remedial recommendations for each observable hazard outweighed the additional effort to generate the recommendations.

The utility of such a taxonomy for STF hazards has already been described in the earlier section on its application. Although, the systematic hazard assessment was successfully completed, it did involve making significant revisions to the taxonomy to reduce the number of categories for the observational study. The taxonomy’s strengths were more apparent when developing the STF checklists. However, these checklists and their use in the next iteration of ErgoMine (Nasarwanji et al., 2021) still need to be validated through usability testing and an evaluation of inter-rater and test-retest reliability.

The development of the STF taxonomy does have its limitations. The inclusion/exclusion criteria for standards were not specific; however, attempts were made to include all regulatory standards in the United States and commonly referenced guidelines and standards. Standards are likely to evolve and be revised over time. Hence, the taxonomy should also be updated when significant changes are made to standards and guidelines. Although some of the standards used have more recent versions available, the changes made were not significant enough to update the taxonomy at this time, and the versions included in the taxonomy are still representative of the standards. The taxonomy may not be all inclusive, and specific areas excluded are clearly specified and some STF hazards, not clearly identifiable in the current standards, may have also been excluded. Underground operations were excluded due to unique requirements of the work environment. Mobile equipment and portable and extension ladders were previously investigated and hence excluded (Moore et al., 2009; Nasarwanji et al., 2018; Pollard et al., 2019; Santos et al., 2010). Personal fall arrest systems, fall protection, and ladder fall arrest systems were not considered as part of the taxonomy. The importance of fall protection in preventing fall incidents in the mining industry is not trivial (Hrica et al., 2020; Nasarwanji, 2016), and the NIOSH researchers feel it warrants its own dedicated investigation and analysis. Experts, outside of the National Institute for Occupational Safety and Health (NIOSH), were not included as part of the STF hazard taxonomy development; however, the authors have diverse backgrounds with all having some expertise in slip, trip, and fall prevention in the mining industry. Finally, there is a level of subjectivity to the process of the taxonomy development. However, care was taken at each step to ensure that the hazards extracted from the taxonomy were checked against the standards at multiple points and input from multiple researchers with expertise in the mining industry, and STF were combined to develop the final observable hazards and recommendations.

Hazard identification is a critical step in creating safe work environments. The identification and subsequent remediation of slip, trip, and fall hazards may lead to significant injury reductions in the mining industry. Although a number of regulations and standards were used, the goal was to provide specific recommendations for proactive design and reactive assessment of walkways, stairways, and fixed ladders for use by mines. The STF hazard taxonomy developed under this effort can be directly used to inform the development of tools to improve the identification and remediation of slip, trip, and fall hazards at surface mining facilities, thereby improving safety and preventing occupational injuries.