A taxonomy of surface mining slip, trip, and fall hazards as a guide to research and practice.

Slips, trips, and falls (STFs) are the second leading cause of non-fatal injuries and can lead to fatal incidents in the mining industry. Hazard identification is an essential first step in remediating STF hazards and creating a safer work environment. Previous research has identified industry-specific risk factors for STFs, evaluated exposures to those risk factors, and developed taxonomies of the hazards for the construction and farming sectors. In comparison, ErgoMine-a mobile device application-based ergonomics audit tool-is the only systematic evaluation tool that covers STF hazards in the mining industry. However, ErgoMine was not specifically developed to address STF hazards. This paper describes the development of a taxonomy that helps identify STF hazards at surface mining sites and provides recommendations to address these hazards to inform future evaluation tools. The objective was to develop a taxonomy that was self-explanatory, observable, repeatable, and solution oriented. In addition to current regulations, standards and guidelines were used to develop the taxonomy to ensure the focus was beyond basic compliance. A detailed description of how the STF hazard taxonomy was created for walkways, stairways, and fixed ladders is provided, along with two specific applications of its use. The STF hazard taxonomy can be used to develop tools like checklists and ergonomics audits to identify and remediate slip, trip, and fall hazards at surface mining facilities, thereby improving worker safety.

Ergonomics assessment methods used by ergonomics professionals.

A web-based survey was conducted of ergonomics practitioners holding certifications in the U.S., Canada, Great Britain, Australia, and New Zealand. The survey follows 12 years after an earlier initial survey reported by Dempsey et al. (2005). Approximately 1221 eligible participants were invited by e-mail to participate, and 405 surveys were included in the final analysis. The survey queried use of basic instruments relevant to ergonomic practice as well as more specific analytical tools such as observational techniques for assessing postural demands of work and instrumentation for direct measurement of such demands. Some ergonomic assessment methods appear to have increased in their overall use by U.S. ergonomists compared to 2005 data. This was observed for: RULA, REBA, Psychophysical Upper Extremity Data, Strain Index, and ACGIH TLV for Hand Activity Level. There is minimal evidence of increased overall use of direct measurement approaches in the U.S. There appear to be geographic differences between countries/continents in terms of use of various methods. The use of mobile device/smart phone "apps" by ergonomists was queried and these technologies presently appear to be in early adoption phase with 24-28% of practitioners reporting use of an app in their ergonomics practice.

Risk assessment of recordable occupational hearing loss in the mining industry.

Objective: To evaluate the hearing loss risk in different sectors and subunits in the mining industry and to identify associated occupations, in an attempt to locate gaps between hearing conservation efforts and hearing loss risks.Design: Descriptive statistics and frequency tables were generated by commodity types, subunit operations, and/or occupations. Temporal trends of the incidences of hearing loss were reported by commodity types.Study Sample: The MSHA Accident/Injury/Illness and MSHA Address/Employment databases from 2000 to 2014 were used.Results: Incidence rate of OHL was reported highest in the coal sector compared to other commodity types. Those members of the workforce that entered the mining industry after the year 2000 accounted for 6.5% and 19.0% of the total hearing loss records for coal and non-coal, respectively. High-risk occupations found in all three commodity sectors (coal; stone, sand, and gravel; and metal/non-metal) were electrician/helper/wireman, mechanic/repairman/helper, bulldozer/tractor operator, and truck driver.Conclusion: Hearing loss risks were not uniform across mining sectors, subunit operations, and occupations. In addition to the continuous efforts of implementing engineering controls to reduce machinery sound level exposure for operators, a multi-level approach may benefit those occupations with a more dynamic exposure profile - e.g., labour/utilityman/bullgang, electrician/helper/wireman, and mechanic/repairman/helper.

Emerging Ergonomics Issues and Opportunities in Mining.

Ergonomics is the scientific discipline that investigates the interactions between humans and systems to optimize both human and system performance for worker safety, health, and productivity. Ergonomics is frequently involved either in the design of emerging technologies or in strategies to alleviate unanticipated human performance problems with emerging technologies. This manuscript explores several such emerging issues and opportunities in the context of the mining sector. In mining, the equipment, tools, and procedures have changed considerably and continue to change. Body-worn technology provides a number of opportunities to advance the safety and health of miners, while teleoperation and autonomous mining equipment stand to benefit significantly from ergonomics applications in other sectors. This manuscript focuses on those issues and opportunities that can impact the safety and health of miners in the near term.

Precision based guidelines for sub-maximal normalisation task selection for trunk extensor EMG.

AIM: The object of this study was to quantify the contribution of sub-maximal normalisation to the overall variance of exposure parameters describing erector spinae (ES) activity, and to provide guidelines for task selection which minimize methodological variance. METHODS: ES EMG was measured from three locations (T9, L1 and L5 levels) on fifteen men performing a manual materials handling task in the laboratory on three separate days. Four repeats of each of eleven sub-maximal normalisation tasks (eight static, three dynamic) were collected, work data were normalised to each task and repeat, and exposure parameters calculated. The unique contribution of normalisation to the overall variance was determined for each task and exposure parameter using variance component analyses. Normalisation tasks were scored according to their relative contributions to the overall variance and coefficients of variation. RESULTS: A prone task, similar to the Biering-Sørensen test posture, was the most repeatable for all electrode locations and across all exposure parameters. Thoracic level normalisation typically showed poorer repeatability than lumbar normalisation. DISCUSSION: To maximize measurement precision, we recommend that future ES EMG studies employing sub-maximal normalisation utilise said prone task. An alternate normalisation task specific to thoracic level ES muscles may be warranted.

Examination of space/volume requirements for US underground coal mine refuge alternatives.

The Mine Safety and Health Administration requires that 1.4 m2 (15 ft2) of floor space is to be provided for each person inside a refuge alternative (RA). However, the amount of floor space needed for a person to reside inside an RA and perform basic tasks is unknown. During testing, participants entered into an RA or a simulated RA of various space/volume configurations and performed several simulated tasks that are representative of the survivability tasks performed within an RA. The results indicate that the floor space requirements were generally adequate for the tasks studied. Certain tasks such as changing scrubber cartridges, using toilets, and moving about the RA were impacted by the minimum height tested (0.6 m). As such, RAs of this height will require critical design consideration as a whole and the supplies provided for use inside of the RA to ensure the ability to use an RA.

Development of ergonomics audits for bagging, haul truck and maintenance and repair operations in mining.

The development and testing of ergonomics and safety audits for small and bulk bag filling, haul truck and maintenance and repair operations in coal preparation and mineral processing plants found at surface mine sites is described. The content for the audits was derived from diverse sources of information on ergonomics and safety deficiencies including: analysis of injury, illness and fatality data and reports; task analysis; empirical laboratory studies of particular tasks; field studies and observations at mine sites; and maintenance records. These diverse sources of information were utilised to establish construct validity of the modular audits that were developed for use by mine safety personnel. User and interrater reliability testing was carried out prior to finalising the audits. The audits can be implemented using downloadable paper versions or with a free mobile NIOSH-developed Android application called ErgoMine. Practitioner Summary: The methodology used to develop ergonomics audits for three types of mining operations is described. Various sources of audit content are compared and contrasted to serve as a guide for developing ergonomics audits for other occupational contexts.

Analysis of physical demands during bulk bag closing and sealing.

Several tools are sold and recommended for closing and sealing flexible intermediate bulk containers (bulk bags) which are used to transport product that has been mined and processed. However, there is limited information on the risks, physical demands, or the benefits of using one tool over another. The purpose of this study was to evaluate the physical demands involved with two closing methods and several sealing tools in order to provide recommendations for selecting tools to reduce exposure to risk factors for work-related musculoskeletal disorders. In this study, twelve participants completed bag closing and sealing tasks using two different closing methods and eight sealing tools on two types of bulk bags. Physical demands and performance were evaluated using muscle activity, perceived exertion, subjective ratings of use, and time. Results indicate that using the "flowering" method to close bags required on average 32% less muscle activity, 30% less perceived exertion, 42% less time, and was preferred by participants compared to using the "snaking" method. For sealing, there was no single method significantly better across all measures; however, using a pneumatic cable tie gun consistently had the lowest muscle activity and perceived exertion ratings. The pneumatic cable tie gun did require approximately 33% more time to seal the bag compared to methods without a tool, but the amount of time to seal the bag was comparable to using other tools. Further, sealing a spout bulk bag required on average 13% less muscle activity, 18% less perceived exertion, 35% less time, and was preferred by participants compared to sealing a duffle bulk bag. The current results suggest that closing the spout bag using the flowering method and sealing the bag using the pneumatic cable tie gun that is installed with a tool balancer is ergonomically advantageous. Our findings can help organizations select methods and tools that pose the lowest physical demands when closing and sealing bulk bags.

Slip Potential for Commonly Used Inclined Grated Metal Walkways.

BACKGROUND: No specific guidelines or regulations are provided by the Mine Safety and Health Administration for the use of inclined grated metal walkways in mining plants. Mining and other companies may be using walkway materials that do not provide sufficient friction, contributing to slip and fall injuries. PURPOSE: The purpose of this study was to determine if there are significant differences in the required friction for different grated metal walkways during walking in diverse conditions. METHODS: The normalized coefficients of friction were measured for 12 participants while walking up and down an instrumented walkway with different inclinations (0°, 5°, 10°, 15°, and 20°) and with and without the presence of a contaminant (glycerol). Self-reported slip events were recorded and the required coefficients of friction were calculated considering only the anterior/posterior components of the shear forces. Additionally, the available coefficients of friction for these walkway materials were measured at the 0° orientation using a tribometer, with and without the presence of the contaminant, using a boot heel as well as Neolite as the test feet. RESULTS: The number of slips increased when the inclination angle reached 10° and above. Of all materials tested, the diamond weave grating was found to have the best performance at all inclines and when contaminated or dry. A high number of slips occurred for the perforated grating and serrated bar grating at 20° when contaminated. CONCLUSIONS: Results of this study suggest that the diamond weave grating provides significantly better friction compared to serrated bar and perforated gratings, especially at inclines greater than 10°.

Analysis of Fatalities During Maintenance and Repair Operations in the U.S. Mining Sector.

BACKGROUND: Maintenance and repair work in mining is particularly hazardous and yet has received little focus in ergonomics research. PURPOSE: In this article, an attempt has been made to determine if patterns can be identified to categorize maintenance and repair fatalities in mining, to compare occurrence of fatalities between coal and metal/nonmetal sectors, and to use this information to identify safety deficiencies and associated proposed remedial measures. METHODS: A classification scheme was developed to identify patterns in fatalities, including proximal causes, tasks, and contributing factors. This scheme was tested to ensure adequacy of the categories, and fatalities were categorized using the scheme. All testing and categorization were done by two of the authors to ensure reliability of the coding scheme. RESULTS: Patterns were successfully identified to categorize the fatalities, and these patterns were different between coal and metal/nonmetal mines. Coal mines had a greater proportion of electrical-related fatalities, while more fatalities related to potential energy occurred at metal/nonmetal mines. Most of the fatalities were caused by the victim coming into contact with an object or machine or the victim falling from height, and they occurred most often while the victim was performing maintenance or repair on equipment, cleaning, or removing blockages. The most frequent factors contributing to these incidents were failure to properly de-energize or lock out/tag out equipment, violation of work procedures, missing or inadequate safety equipment, and failure to block equipment properly. CONCLUSIONS: The classification approach used was successful in identifying hazard patterns during maintenance and repair fatalities in mining. These patterns identify areas to focus attention when developing interventions to prevent the occurrence of future fatalities.

Maintenance and repair injuries in US mining.

PURPOSE ­: The purpose of this paper is to identify key tasks, tools, and equipment associated with maintenance and repair injuries at US mines and to provide some mitigation strategies to reduce these types of injuries. DESIGN/METHODOLOGY/APPROACH ­: This study analyzed incidents resulting in injuries reported to the US Mine Safety and Health Administration from 2002 to 2011. Incident reports were limited to those occurring at mining plants, shops, yards, and aboveground locations. Incident reports were analyzed to determine which activities contributed to injuries and were due to machine maintenance and repair, non-powered hand tools, and powered hand tools. An in-depth analysis of the root causes of these injuries was then performed. FINDINGS ­: Maintenance and repair in mining is associated with a significant number of hand and finger injuries with a range of severities and averaging over 20 amputated fingers, 180 fractured hands and fingers, and 455 hand and finger lacerations per year. Many of these injuries are caused by hands being struck by or caught in tools and equipment. Back and shoulder strains are found to be associated with the most days lost from work and are mostly attributed to materials handling. PRACTICAL IMPLICATIONS ­: Occupational injuries and fatalities still occur with high incidences in the mining sector. The mission of the Office of Mine Safety and Health Research (OMSHR; part of the National Institute for Occupational Safety and Health, NIOSH) is to "eliminate mining fatalities, injuries, and illnesses through research and prevention." As part of this work, OMSHR acquires surveillance data from MSHA to quantify the types and sources of injuries at US mining facilities. The authors evaluated maintenance- and repair-related injuries at US mining sites (excluding underground coal mines). Results of this study suggest a need for improved design of machine guarding, improved hand protection through gloves and equipment design/redesign, and manual materials handling solutions. ORIGINALITY/VALUE ­: The findings indicate that maintenance and repair in mining include occupational risks that may be managed through modifications to machines, proper usage of hand tools and hand protection, and improved manual materials handling processes.

The effect of cap lamp lighting on postural control and stability.

Researchers at the National Institute for Occupational Safety and Health (NIOSH) are conducting mine illumination research with the objective of improving miner safety. Slips, trips, and falls (STFs) are the second leading accident class (18.1%, n = 2,374) of nonfatal lost-time injuries at underground mines (MSHA, 2005-2009). Factors contributing to STFs include recognition of hazards as well as postural balance and age. Improved lighting may enable better hazard recognition and reduce the impact of postural balance and age. Previous research has shown that cap lamp technology that used light-emitting diodes (LEDs) has improved hazard detection. This study was an initial investigation to determine if cap lamp lighting significantly influences measures of static postural stability (displacement and velocity of center of pressure). Results of this investigation showed no significant differences in the balance measures of interest between cap lamps tested. However, balance was shown to significantly decline (p < 0.05) when tested in an underground coal mine compared to the laboratory testing condition. Relevance to industry: Underground coal mine workers wear cap lamps on their hard hats as their primary light source to illuminate nearby areas where their vision is directed. Proper illumination may improve miner safety by improving their STF hazard recognition and balance.

Gender differences in psychophysically determined maximum acceptable weights and forces for industrial workers observed after twenty years.

PURPOSE: In the year 1991, manual materials handling guidelines were published by Liberty Mutual Research Institute for Safety. In these guidelines, maximum acceptable weights (MAWs) and forces (MAFs) for lifting, lowering, pushing, pulling, and carrying were derived from studies conducted in a 20 year span before the above publication date. The question is whether the present generation of workers has retained the same gender differences and absolute values in psychophysically determined MAWs and MAFs as those reflected in the guideline. METHODS: Twenty-four female industrial workers performed 20 variations of lifting, lowering, pushing, pulling, and carrying. A psychophysical methodology was used whereby the workers chose a workload they could sustain for 8 h without "straining themselves or without becoming unusually tired, weakened, overheated or out of breath." RESULTS: In females, MAWs of lifting, lowering, and carrying averaged 53% of the present-day male values, similar to the 55% in the guideline. MAFs of pushing and pulling were 83 and 86% of the present-day male values but slightly higher than the 73 and 78% in the guideline, respectively for initial and sustained forces. CONCLUSIONS: The similarity of gender differences between the guideline and the present findings was coupled with dramatic decreases in MAWs of lifting, lowering, and carrying. Such decreases may reflect a new psychophysical set point; however, considerations about adjusting existing guidelines on lifting, lowering, and carrying may not be appropriate until additional data from other sources inside and outside the US confirm the present findings.

Influence of three principles of pacing on the temporal organisation of work during cyclic assembly and disassembly tasks.

A study was conducted to investigate the influence of different approaches to arranging the pace and temporal organisation of repetitive assembly and disassembly tasks on both average performance and its variability and to compare assembly and disassembly times derived with psychophysical methods to a more traditional methods-time measurement (MTM) approach. The conditions studied were a traditional assembly line arrangement, where assemblies were started at a pace of 110 MTM (repeated on two occasions), a batch condition, where subjects were required to complete 36 assemblies within the total amount of time allowed at 110, MTM and a psychophysical condition, where subjects were allowed to choose their pace (repeated on two occasions). Overall, the results suggest that the mean time spent working in each cycle (the 'on-time') remained fairly constant across conditions, while the idle 'off-time' in between on-times was shorter and of less varied duration in the more autonomous batch and psychophysical conditions. During the second psychophysical (self-paced) condition, subjects completed a significantly higher number of assemblies than during the 110 MTM line condition. The higher pace was achieved through reduction in mean off-times and the potential implications for musculoskeletal risk are discussed. STATEMENT OF RELEVANCE: Higher levels of autonomy over work pace, which intuitively would be beneficial from an ergonomics standpoint, actually led to subjects selecting to organise work such that off-times (idle times) were reduced. In contrast, active 'on' times were not affected much by autonomy. These results point to a reason that piecework would be associated with increased risk for musculoskeletal disorders.

Gender comparison of psychophysical forces, cardiopulmonary, and muscle metabolic responses during a simulated cart pushing task.

The purpose was to compare psychophysiological responses between healthy male and female workers during dynamic pushing. Using a psychophysical approach, 27 participants chose an acceptable force that they could push over a 7.6m distance at a frequency of 1 push per min on a treadmill. On a separate day, cardiopulmonary (e.g., whole-body oxygen uptake, heart rate, ventilation volume) and muscle metabolic measurements (change in muscle blood volume [ΔtHb] and Tissue Oxygenation Index [TOI]) from the right and left gastrocnemius muscles were collected simultaneously while participants pushed the previously chosen acceptable force on the treadmill at a similar frequency and distance for 2h. Results showed no significant difference between men and women for integrated force exerted on the instrumented treadmill handle and cardiopulmonary responses. In contrast, women demonstrated 45.7% lower ΔtHb but 3.6% higher TOI in the gastrocnemius region as compared to men, suggesting a lower hemoglobin concentration in women and high venous oxygen saturation during pushing. When ΔtHb and TOI were corrected for both body mass and pushing force, the disparity in gender was retained, implying an increased muscle oxygen saturation per force development in women than men during pushing. In the left gastrocnemius region, ΔtHb was 60% lower and TOI was 5.7% higher in women than men, suggesting an uneven muscle loading during pushing. Overall, the gender similarity in cardiopulmonary responses versus disparity in muscle metabolic responses suggest the importance of evaluating human performance during physical work at both whole-body and localized muscle levels.

Accuracy of the Borg CR10 scale for estimating grip forces associated with hand tool tasks.

The gripping of tools is required by many industrial operations, and an important aspect of exposure assessment is determining the grip force output of operators. Ratings of perceived exertion can provide an indirect measure of grip force; however, reports in the literature of the use of Borg CR10 scale ratings as a surrogate measure of grip force have been mixed. During a laboratory study with 16 participants, power grip forces were measured directly during three hand tool task simulations: (1) a screwdriver task, (2) a ratchet task, and (3) a lift and carry task, each performed at four force/load levels. Borg scale ratings reported following each trial were compared with mean, peak, and integrated grip forces for the respective trials. Pearson correlations conducted on an individual basis were greatest for the screwdriver task, r approximately 0.9. Correlations for integrated grip force were generally better than for mean or peak force. Correlations were also performed on data pooled for all participants, simulating a cross-sectional sampling approach. Correlations made with pooled data were weaker than when conducted on an individual basis, ranging from r = 0.26 for peak grip force for the lift and carry task, to r = 0.79 for the screwdriver task. When the pooled data were normalized to individual maximum voluntary grip exertions, correlation generally improved but not to the level of the "individually scaled" data. Based on these findings, a protocol is proposed that could improve the strength of correlations between direct measures of grip force and ratings of perceived exertion. Differences in strength of correlation between task simulations are discussed with respect to differences observed in force distributions about the handle for the three tasks.

Psychophysically determined forces of dynamic pushing for female industrial workers: Comparison of two apparatuses.

Using psychophysics, the maximum acceptable forces for pushing have been previously developed using a magnetic particle brake (MPB) treadmill at the Liberty Mutual Research Institute for Safety. The objective of this study was to investigate the reproducibility of maximum acceptable initial and sustained forces while performing a pushing task at a frequency of 1min(-1) both on a MPB treadmill and on a high-inertia pushcart. This is important because our pushing guidelines are used extensively as a ergonomic redesign strategy and we would like the information to be as applicable as possible to cart pushing. On two separate days, nineteen female industrial workers performed a 40-min MPB treadmill pushing task and a 2-hr pushcart task, in the context of a larger experiment. During pushing, the subjects were asked to select a workload they could sustain for 8h without "straining themselves or without becoming unusually tired, weakened, overheated or out of breath." The results demonstrated that maximum acceptable initial and sustained forces of pushing determined on the high inertia pushcart were 0.8% and 2.5% lower than the MPB treadmill. The results also show that the maximum acceptable sustained force of the MPB treadmill task was 0.5% higher than the maximum acceptable sustained force of Snook and Ciriello (1991). Overall, the findings confirm that the existing pushing data developed by the Liberty Mutual Research Institute for Safety still provides an accurate estimate of maximal acceptable forces for the selected combination of distance and frequency of push for female industrial workers.

Fall from equipment injuries in U.S. mining: identification of specific research areas for future investigation.

INTRODUCTION: The objective of this study was to evaluate the circumstances leading to fall from equipment injuries in the mining industry. METHOD: The 2006 and 2007 Mine Safety and Health Administration annual injury databases were utilized for this study whereby the injury narrative, nature of injury, body part injured, mine type, age at injury, and days lost were evaluated for each injury. RESULTS: The majority of injuries occurred at surface mining facilities (approximately 60%) with fractures and sprains/strains being the most common injuries occurring to the major joints of the body. Nearly 50% of injuries occurred during ingress/egress, predominantely during egress, and approximately 25% of injuries occurred during maintenance tasks. The majority of injuries occurred in relation to large trucks, wheel loaders, dozers, and conveyors/belts. The severity of injury was independent of age and the median days lost was seven days; however, there was a large range in severity. IMPACT ON INDUSTRY: From the data obtained in this study, several different research areas have been identified for future work, which include balance and stability control when descending ladders and equipment design for maintenance tasks.

An analysis of injury claims from low-seam coal mines.

INTRODUCTION: The restricted workspace present in low-seam coal mines forces workers to adopt awkward working postures (kneeling and stooping), which place high physical demands on the knee and lower back. METHOD: This article provides an analysis of injury claims for eight mining companies operating low-seam coal mines during calendar years 1996-2008. All cost data were normalized using data on the cost of medical care (MPI) as provided by the U.S. Bureau of Labor Statistics. RESULTS: Results of the analysis indicate that the knee was the body part that led in terms of claim cost ($4.2 million), followed by injuries to the lower back ($2.7 million). While the average cost per injury for these body parts was $13,100 and $14,400, respectively (close to the average cost of an injury overall), the high frequency of these injuries resulted in their preeminence in terms of cost. Analysis of data from individual mining companies suggest that knee and lower back injuries were a consistent problem across companies, as these injuries were each among the top five most costly part of body for seven out of eight companies studied. APPLICATION/IMPACT: Results of this investigation suggest that efforts to reduce the frequency of knee and low back injuries in low-seam mines have the potential to create substantial cost savings.