IC 9475 

INFORMATION CIRCULAR/2004
 

Department of Health and Human Services

Centers for Disease Control and Prevention 

National Institute for Occupational Safety and Health 

Ergonomic Assessment of Musculoskeletal Risk 

Factors at Four Mine Sites: Underground Coal, 

Surface Copper, Surface Phosphate, and 

Underground Limestone 
Information Circular 9475 

Ergonomic Assessment of Musculoskeletal Risk 

Factors at Four Mine Sites: Underground Coal, 

Surface Copper, Surface Phosphate, and Underground 

Limestone 

By William J. Wiehagen and Fred C. Turin 

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES
 Centers for Disease Control and Prevention
 

National Institute for Occupational Safety and Health
 

Pittsburgh Research Laboratory
 

Pittsburgh, PA
 

August 2004 
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DHHS (NIOSH) Publication No. 2004–159 
CONTENTS
 Page 

Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 
 

Acknowledgments .............................................................................. 2 
 

Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 
 

Background ................................................................................... 3 
 

Risk factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 
 

Methods and tools .............................................................................. 4 
 

Site selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 
 

Baseline data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 
 

Incident data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 
 

Nordic questionnaire ........................................................................ 6 
 

Supervisor interview guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 
 

Management concerns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 
 

Job selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 
 

Task analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 
 

Body part discomfort interview guide ............................................................. 7 
 

Brainstorming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 
 

Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 
 

Selecting work activities and tasks ............................................................... 7 
 

MSD risk factors for selected work tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 
 

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 
 

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 
 

Appendix A.—Ergonomic interventions for the mining industry: an overview of planned approach . . . . . . . . . . . . . . . 13 
 

Appendix B.—Nordic questionnaire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 
 

Appendix C.—Front-line supervisor interview guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 
 

Appendix D.—Body part discomfort interview guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 
 

Appendix E.—Sample decision matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 
 

Appendix F.—Underground coal mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 
 

Appendix G.—Surface copper mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 
 

Appendix H.—Surface phosphate mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 
 

Appendix I.—Underground limestone mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 
 

ILLUSTRATIONS 

1. Overall study strategy ...................................................................... 5 
 

TABLES 

1. Mine descriptions, tools used to select tasks, and tasks selected across the four sites . . . . . . . . . . . . . . . . . . . . . . 8 
 

2. Risk factors by observed tasks: underground coal mine ............................................ 9 
 

3. Risk factors by observed tasks: surface copper mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 
 

4. Risk factors by observed tasks: surface phosphate mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 
 

5. Risk factors by observed tasks: underground limestone mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 
 

E–1. Sample decision matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 
 

F–1. Underground coal: number of incidents and employees by job title and incident rate, 1996–1998 . . . . . . . . . . . 23 
 

F–2. Underground coal: incidents by occupational class and incident type, 1996–1998 . . . . . . . . . . . . . . . . . . . . . . . 24 
 

F–3. Underground coal: roof bolter operator – installing bolts and manual materials handling . . . . . . . . . . . . . . . . . . 24 
 

F–4. Underground coal: continuous miner operator – cutting coal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 
 

F–5. Underground coal: shuttle car operator – transporting coal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 
 

F–6. Underground coal: motormen – unloading supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 
 

G–1. Surface copper: number of incidents and employees by work area and incident rate, 1996–1998 . . . . . . . . . . . . 26 
 

G–2. Surface copper: incidents by work group and incident type, 1996–1998 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 
 

G–3. Surface copper: ratings of body part discomfort by work area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 
 
TABLES–Continued 

Page 

G–4. Surface copper: decision matrix for selecting tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 
 

G–5. Surface copper: smelter operator – converter turnaround . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 
 

G–6. Surface copper: smelter operator – 4B–5 gun rebuild . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 
 

G–7. Surface copper: refinery operator – cell checking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 
 

G–8. Surface copper: tank house operator – bar pulling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 
 

H–1. Surface phosphate: number of incidents and employees by job title and incident rate, 1996–1998 . . . . . . . . . . . 30 
 

H–2. Surface phosphate: incidents by job title and incident type, 1996–1998 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 
 

H–3. Surface phosphate: ratings of body part discomfort by work area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 
 

H–4. Surface phosphate: physically demanding jobs identified by supervisors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 
 

H–5. Surface phosphate: float crew – wrenching pipes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 
 

H–6. Surface phosphate: hydraulic pit station operator – operating hydraulic pit station . . . . . . . . . . . . . . . . . . . . . . . 32 
 

H–7. Surface phosphate: dozer operation – moving material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 
 

H–8. Surface phosphate: reagent operator – emptying reagent cars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 
 

I–1. Underground limestone: number of incidents and employees by work area, job title, and incident rate, 

January 1997–May 2000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 
 

I–2. Underground limestone: incidents by work group and incident type, January 1997–May 2000 . . . . . . . . . . . . . 35 
 

I–3. Underground limestone: number of reported body parts with discomfort by work group . . . . . . . . . . . . . . . . . . 35 
 

I–4. Underground limestone: Nordic questionnaire responses by work group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 
 

I–5. Underground limestone: physically demanding jobs identified by supervisors . . . . . . . . . . . . . . . . . . . . . . . . . . 36 
 

I–6. Underground limestone: decision matrix for selecting tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 
 

I–7. Underground limestone: quality control technician – gathering and testing samples . . . . . . . . . . . . . . . . . . . . . . 37 
 

I–8. Underground limestone: blasting crew – handling ANFO and dynamite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 
 

I–9. Underground limestone: blasting crew – hand scaling and clearing bottom holes . . . . . . . . . . . . . . . . . . . . . . . . 38 
 

I–10. Underground limestone: scaling machine operator – mechanical scaling of face and back .............. 38
 

UNIT OF MEASURE ABBREVIATIONS USED IN THIS REPORT 

ft foot ° degree 

in inch °F degree Fahrenheit 

lb pound % percent 

min minute 
 

 

 

ERGONOMIC ASSESSMENT OF MUSCULOSKELETAL RISK FACTORS 

AT FOUR MINE SITES:
 

UNDERGROUND COAL, SURFACE COPPER, SURFACE PHOSPHATE,
 

AND UNDERGROUND LIMESTONE
 

By William J. Wiehagen1 and Fred C. Turin1 

1

Industrial engineer, Pittsburgh Research Laboratory, National Institute for Occupational Safety and Health, Pittsburgh, PA. 

ABSTRACT

 This study examined musculoskeletal injury risk at four mining sites: underground coal, underground 

limestone, surface copper, and surface phosphate. Each site offered opportunities to investigate musculoskeletal 

disorder (MSD) injury risks and how those risks might be identified and categorized. The National Institute 

for Occupational Safety and Health (NIOSH) worked with these sites to (1) identify work activities that showed 

evidence of MSD injury risk, (2) examine physical risk factors that can lead to MSDs for a handful of work 

tasks at each site, and (3) develop a set of ideas for problem-solving to help reduce risk factors for examined 

work tasks. 

For each site, NIOSH implemented a plan that was refined over the time period of this study. The plan 

consisted of four steps. The first step was to use mine injury records, a musculoskeletal discomfort questionnaire, front-line supervisor interviews, and a list of management concerns to identify work groups and work 

activities that have significant evidence of MSD risk factors. The second step was to select work tasks for 

evaluation. The third step was to interview those who do the work and make observations to characterize the 

MSD risk factors and musculoskeletal symptoms that exist for target tasks. The final step was to conduct 

brainstorming sessions with workers who perform the work or have a stake in the production task. The 

brainstorming sessions served to identify general strategies (ideas) for reducing MSD risk factor exposures. 

A final report of findings was presented to mine management and workforce representatives at each site. 

The risk factors and ideas for improvement identified for each site were specific to the target tasks examined. 

These target tasks were diverse, but there were some key similarities. For instance, jobs were found at each 

site that required a significant amount of manual work involving the upper extremities and low back. Handling 

heavy and awkward objects, forceful arm and shoulder exertions, and working in awkward postures were 

common for a variety of jobs across the four sites. 
2 

ACKNOWLEDGMENTS
 

This report is based on the work of four NIOSH teams. The 

efforts involved establishing a plan, visiting mine sites to gather 

site-wide and task-specific information, analyzing and synthesizing information (via observations, interviews, and physical 

measurements), and preparing site-specific feedback reports. 

Contributors to the mine site teams were: 

Underground coal.—Lisa J. Steiner, Eric R. Bauer, Ph.D., 

Kim M. Cornelius,2

2

Now with the National Personal Protective Technology Laboratory, National Institute for Occupational Safety and Health, Pittsburgh, PA. 

Fred C. Turin, Sean Gallagher, Ph.D.; 

Surface copper.—Sean Gallagher, Ph.D., Fred C. Turin, 

William J. Wiehagen, Albert H. Cook; 

Surface phosphate.—Eric R. Bauer, Ph.D., Lisa J. Steiner, 

Lynn L. Rethi,2

 Albert H. Cook, Kim M. Cornelius, Fred C. 

Turin; and 

Underground limestone.—Fred C. Turin, Kim M. Cornelius, 

William J. Wiehagen, Albert H. Cook. 

GLOSSARY
 

Musculoskeletal disorder (MSD).—A condition or disorder 

that involves the muscles, nerves, tendons, ligaments, joints, 

cartilage, or spinal discs. These disorders are not typically the 

result of a distinctive, singular event, but are more gradual in 

their development. Thus, MSDs are cumulative-type injuries. 

Acute injury.—A singular, traumatic event resulting in a disruption of tissues, resulting in pain [Kumar 2001]. 

MSD risk factors.—Actions or conditions that increase the 

likelihood of injury to the musculoskeletal system. Risk factors 

have components of duration, frequency, and level of exposure. 

Exposure to MSD risk factors leads to discomfort and pain, 

which over time can lead to more serious disorders of the musculoskeletal system. 

Ergonomics.—A discipline or science of fitting workplace 

conditions and job demands to the capabilities of the worker. 

Many consider ergonomics a multidisciplinary field of applied 

science where knowledge about human capabilities, skills, limitations, and needs is taken into account when examining the interactions among people, technology, and the work environment 

[Westgaard and Winkel 1997; Cohen et al. 1997]. 
3 

BACKGROUND
 

Mining is often characterized as being very difficult with 

challenging conditions. Whether on the surface or underground, 

the process of extracting minerals can be characterized as 

dynamic [Steiner et al. 1999; Scharf et al. 2001]. Researchers 

suggest that the mining workplace itself is in a state of constant 

change. Dynamic work processes3

3

Examples of dynamic work environments include mining, construction, 

agriculture, and transportation. 

in particular introduce health 

and safety risks, and these risks are not always constant. Furthermore, these risks are not always treatable through hierarchal 

models, suggesting a ranked emphasis on engineering controls, 

administrative controls, and personal protective equipment 

[Scharf et al. 2001]. Hazards are part of the mining process and 

offer challenges to the mining community to research and evaluate strategies to help mitigate the hazards. Realistically, the 

goal is not one of eliminating hazards, but one of reducing the 

risk of injury. For this to happen, hazards and their associated 

risk must be recognized by those who perform, manage, or have 

a stake in the task. 

Musculoskeletal disorders (MSDs) have been identified as a 

significant and costly problem for the mining industry. Stobbe 

and Bobick [1986] reported that strain and sprain injuries in 

1983 and 1984 accounted for 24.0% and 25.2% of all reported 

injuries for underground coal mining, respectively, and 19.4% and 

20.4% of all injuries for underground metal/nonmetal mining, 

respectively. The U.S. Bureau of Labor Statistics [1991] reported 

that mining is among the most hazardous occupations in terms of 

exposure to ergonomic hazards.4

4

The term "ergonomic hazards" refers to musculoskeletal injury risk due to 

extended exposure to MSD risk factors. 

An analysis of results from the 

National Occupational Health Survey of Mining (NOHSM) by 

Zhuang and Groce [1995] found that the magnitude of 

musculoskeletal overload potential exposures for coal mining was 

greater than that for metal/nonmetal mining. In this study, the 

three most common overload conditions for mine workers were 

(1) bending forward, bending to the side, hyperextending or 

twisting the neck or back; (2) unsupported abducted elbows, 

forearms resting on sharp edges, tossing motions at extremes of 

range of motion, working with elbows above shoulders; and 

(3) lifting more than 50 lb, unaided. At least 35% of mine 

workers were potentially exposed to each of these three overload 

conditions. In another study, Winn et al. [1996] analyzed 

NOHSM ergonomic hazard data for 24 commodities associated 

with the metal/nonmetal mining industry. They determined that 

potential exposures to ergonomic hazards were most likely for the 

following body parts: neck and/or back; forearms, arms, and 

shoulders; and fingers and hands. Overall, they believed that the 

potential exposure to ergonomic hazards for metal/nonmetal 

miners was high compared to that for nonmining occupations. 

In addition to these common MSD exposures, the workforce 

is aging in many mining sectors. Fotta and Bockosh [2000] 

found that older (aged 45+) injured workers have the highest 

median number of days lost per injury. They examined injury 

data by type of mining operation and by occupation. The cumulative nature of MSDs suggests that older workers may be 

more at risk because they have potentially many years of 

exposure to physically demanding work. In addition, older 

workers often require a longer period of time to recover from 

injuries. At the same time, older workers usually have a sound 

understanding of the work process and can likely make salient 

suggestions to enhance the process, i.e., make it safer and more 

efficient. Reducing MSD risk factors will enhance the quality 

of life of miners, have a positive effect on the productive capacity of the mining plan, and reduce medical costs associated 

with mine operation. 

The NOHSM studies led to a series of discussions in 1998 

between Mine Safety and Health Administration (MSHA) Technical Support personnel and NIOSH researchers. MSHA was 

interested in learning more about the prevalence of MSDs in the 

mining industry and what might be done to reduce the risk of 

injury. MSHA expressed the need for exploratory field research 

to get a better understanding of MSD risk factors at a variety of 

surface and underground mining sites. These discussions recognized the unique characteristics of mine sites and the wide 

variety of technology, production processes, and conditions that 

typify mining. Injuries to the musculoskeletal system 

(especially back injuries) are common in many mining environments. Identifying and reducing risk factors that can lead to 

MSDs is a proactive approach to prevent acute and chronic 

MSDs. 

Based on these discussions, NIOSH initiated a project entitled "Ergonomic Interventions in Mining," which began in the 

summer of 1998. The project consists of two phases. The goal 

of the first phase was to conduct MSD physical risk factor 

assessments at four mining sites: underground coal, underground limestone, surface copper, and surface phosphate. 

NIOSH worked with these sites to (1) identify work tasks that 

could significantly benefit from additional ergonomic evaluation, (2) examine and categorize physical risk factors that can 

lead to MSDs for the identified work tasks, and (3) develop a set 

of ideas for problem-solving to help reduce risk factors for that 

small set of work tasks examined at each of the four sites. 

This report presents the findings from the first phase. Completion was marked by the feedback report being written and 

presented to the fourth mine site. The study results are presented in a series of tables organized by mining sector and the 

work task studied. Appendices are provided to offer more detailed information about the specific methods and tools used and 

additional results from each of the four sites. 
4 

RISK FACTORS
 

Risk and risk factors are common concepts used in safety and 

applied ergonomics literature. Risk includes a component of

 (1) how likely (i.e., what the probability of) an event is and (2) 

the seriousness of the consequence (i.e., what the severity is) if 

something does occur. Risk is often defined in the past 

tense—looking back and deciding on how many injuries or accidents resulted for a given exposure. At the extremes, injury risk 

can be viewed as (1) very low probability but extremely high 

consequence (e.g., multiple fatalities) or (2) higher probability but 

less severe consequence (e.g., a worker slipping and tripping). 

Risk is also intuitively relative within and across work settings. 

Risk implies a probability for injury, and the odds of an injury are 

a function of the level of risk and worker exposure time. It is 

possible for workers at a site not to have injuries for a period of 

time. The absence of injuries does not imply the absence of risk. 

In the context of this study, risk factors are defined as actions 

or conditions that increase the likelihood of injury to the 

musculoskeletal system. Applied ergonomics literature [Cohen 

et al. 1997; Washington State Department of Labor 1994] 

recognizes a small set of common physical risk factors across 

many occupations and work settings. The relationship between 

risk factor exposures and the level of musculoskeletal injury risk 

is not easily defined. Although physical risk factors are important first-line risk factors, there are other plausible factors 

such as organizational and psychosocial factors that may provoke a disorder or indirectly influence the effect of physical risk 

factors [Hagberg et al. 1995]. However, there is general agreement that multiple risk factors put a worker at greater risk, even 

though the increase (via a mathematical probability) in risk 

cannot be specified. Workers vary in their capacity and ability 

to adjust to job demands; thus, some may be more affected than 

others by exposure to the same risk factors [Cohen et al. 1997]. 

Age also has an effect on variability in worker capacity and 

ability to adjust to job demands.5 

5

The effect of "age" was not examined under this study. However, age is a 

consideration, as there are a lot of normative changes that can and do occur with 

aging. For a complete discussion of age and its potential effect on work 

performance capacities and abilities, see Hagglund [1998]. 

Compared to most other work settings, mining offers 

additional risk complexities due to the dynamic nature of the 

work. The environment changes daily, and new hazards are 

introduced as part of the mining process. Work procedures 

often change to accommodate changes in the work environment. 

Thus, risk factor exposure is not a constant; it varies depending 

on the nature of the task, the conditions that surround the task, 

and the people performing the task.6 

6

This is a key reason why training and education in recognizing MSD risk 

factors is very important. 

This study concerns the identification of physical risk factors, 

within a sample of mining tasks, that can contribute to MSDs/ 

injuries. MSD risk factors7

7

Duration of tasks and environmental conditions also contribute to the 

likelihood of injury. 

that are common to mining 

include— 

• Prolonged, awkward postures 

• Forceful exertions (heavy or frequent lifting) 

• Forceful gripping 

• Highly repetitive motions 

• Jolting/jarring 

• Vibration exposure (hand and arm) 

• Contact stress (pressure points/impact stress) 

Risk factor exposure is an early warning of progressively more 

serious problems—physical signs and symptoms that can lead 

to serious injury. Long-term exposure to risk factors (e.g., 

heavy or frequent lifting in awkward postures) will reduce the 

quality of life. 

Every job carries risk. The key issue is relative risk. Organizations and individuals can become better informed to reduce 

MSD injury risk by (1) being aware of risk factors, 

(2) becoming skilled in recognizing and categorizing these 

factors, and (3) examining options to reduce the frequency or 

duration of exposure to the risk factors. Reducing exposure to 

risk factors should make the task smoother and more predictable 

in its outcome. Reducing risk factor exposure should make task 

performance less variable. 

The first step in reducing risk is to identify those work 

activities that involve significant levels of the seven risk factors, 

or combinations of those factors, identified above. Exposure to 

risk factors not only increases the risk of serious injury, but can 

also routinely inhibit orderly production. 

METHODS AND TOOLS
 

A general protocol (see appendix A) was developed and used 

by the NIOSH team. It helped to guide the field research effort 

once a mine had been contacted and expressed interest in 

participating in the study. A NIOSH project team member served 

as the site coordinator, and a site evaluation team was formed for 

each mine. Each of the four NIOSH teams, using the general 

protocol as a guide, developed a site-specific approach tailored to 

the conditions and constraints encountered at each site. 

This section provides a general overview of the study methods and tools. Because of the exploratory nature of this study, 

the data collection activities at each site were slightly and necessarily different. However, figure 1 represents what the NIOSH 

team considers to be one useful strategy for site-wide 

assessment of MSD injury risk. This assessment leads to 

(1) selecting work activities that would be good candidates for 

further study, (2) working with mine site personnel to better 
5 

Figure 1.–Overall study strategy. 
 

6 

define the MSD injury risk for specific tasks, and (3) exploring 

ideas for improving the work process. Improving the work 

process implies reducing injury risk, i.e., helping to make some 

tasks less physically demanding or stressful. 

SITE SELECTION 

From personal contacts, NIOSH team members identified a 

list of potential sites.8

8

Three primary criteria were chosen: (1) mine cooperation – management 

and workforce representatives should be interested and committed to this work; 

(2) mining environment – a variety of surface and underground environments 

should be examined; and (3) industry impact – the activities evaluated should 

be performed by a number of workers or have characteristics common to 

activities performed by a large number of workers at other mine sites or in other 

industries. 

 A member of the NIOSH team communicated with a mine contact to provide an overview of the 

project goals and requirements. If interest was expressed, an 

overview description was sent to the mine contact to brief the 

mine's management team (see appendix A). If the logistics of 

this work appeared to be feasible, an introductory meeting was 

held with management and workforce representatives, along 

with a representative from MSHA's Technical Support group. 

Following this meeting, if a mine agreed to cooperate, the mine 

site contact person and the NIOSH team member planned the 

details to facilitate the study. 

BASELINE DATA 

To establish a baseline at each site, the NIOSH team used 

a combination of data collection tools: (1) incident data, 

(2) Nordic Questionnaires, (3) first-line supervisor interviews, 

and (4) management concerns. The overall intent of gathering 

baseline data was to form a site-wide picture of relative MSD 

injury risk by work activity. To accomplish this, the NIOSH 

team used both qualitative and quantitative data collection tools. 

This met two objectives: (1) it helped the NIOSH team learn 

more about the mining technology, process, and conditions 

present at each site, and (2) it allowed the team to collaborate 

with workers, front-line supervisors, and management to 

develop an objective and logical structure for selecting work 

tasks for in-depth study. 

Incident Data 

At least 3 years of incident data were obtained for each site. 

This included any available information about incidents 

involving (1) near-misses, (2) medical treatment, and (3) injuries 

that were reportable to MSHA or the Occupational Safety and 

Health Administration. Incident data were summarized using 

spreadsheet software. The summary organized the incident data 

by job classification and accident type (e.g., slip/fall, caught 

between/struck by, sprains/strains). Incident rates by job 

classification were prepared for each site. 

Nordic Questionnaire 

Site-wide employee input was requested via response to a 

general discomfort questionnaire—the Nordic Questionnaire 

[Kuorinka et al. 1987]. These data were gathered at three of the 

four sites to identify musculoskeletal aches and pains existing 

within the working population. The goal was to have as much 

of the workforce as possible fill out a questionnaire. Employees 

were asked to complete the questionnaire after a brief overview 

of the instrument and reasons for its use by a safety representative from the mine or a NIOSH team member. The Nordic 

Questionnaire can be found in appendix B. 

Supervisor Interview Guide 

The NIOSH team prepared a set of interview questions to 

obtain relevant information from first-line supervisors. These 

interviews, conducted at three of the four sites, took about 

30 minutes to administer. The purpose was to learn about the 

variety, scope, and context of work performed at the mine site 

and to obtain insights about the jobs and work tasks that the 

front-line supervisors believed to be the most physically 

demanding. The supervisor interview guide can be found in 

appendix C. 

Management Concerns 

As part of the field work, management9

9

Site employees (management and workforce representatives) collaborated 

in this study. Thus, discussions of management concerns were ongoing, 

especially during the early parts of the site-specific work where the goal was to 

come up with a logical means for selecting work tasks for more in-depth study. 

was asked to identify 

work activities that they thought warranted further study to 

reduce MSD injury risk. 

JOB SELECTION 

Baseline data were used to identify work activities 

considered for further study. Several factors were considered in 

selecting a task, but a key factor was evidence of significant 

MSD risk factor exposure. Tasks selected for additional study 

did not necessarily have the highest (within each site) risk factor 

exposure. The extent that each type of data (i.e., the incident 

data, Nordic Questionnaire, supervisor interviews, and 

management concerns) was used varied based on the constraints 

encountered at each site. However, across all four sites, the 

mine's incident data were thoroughly examined and management 

concerns were clearly identified. 

A decision matrix was used at two of the sites to organize the 

baseline data and offer information to help select tasks for 

further study. A discussion of how the decision matrix was used 

is included in appendix E. 
 

 

 

 

7 

TASK ANALYSIS 

Specific tasks that exposed workers to significant MSD risk 

factors were identified for each candidate job. Using job descriptions acquired from supervisor interviews and discussions 

with mine managers, NIOSH researchers interviewed, observed, 

and videotaped work tasks. Team members observed and 

identified a set of risk factors along with relevant measurements 

of worksite dimensions, force exertions, and the size and 

weights of tools and work pieces. Finally, workers' views of 

their physical job stress were obtained using a Body Part 

Discomfort Interview Guide developed by the evaluation team. 

BODY PART DISCOMFORT INTERVIEW GUIDE 

Workers were interviewed to identify symptoms of discomfort and work activities that contribute to discomfort. The 

interview guide inquired about body part discomfort and 

workers' thoughts about the most physically demanding aspects 

of their work. The interview guide was based on concepts from 

the general form of the Nordic Questionnaire and a symptom 

survey presented as tray 4–A in NIOSH's Elements of 

Ergonomics Programs: A Primer Based on Workplace 

Evaluations of Musculoskeletal Disorders [Cohen et al. 1997]. 

The goal was to identify tasks that workers believed were most 

likely to cause physical discomfort and why they are hard to 

perform. The Body Part Discomfort Interview Guide can be 

found in appendix D. 

Task analysis results were used by the NIOSH evaluation 

team to identify a list of demanding tasks. Following reviews 

with mine management, target tasks were chosen for final 

evaluation to develop ideas for improvement. A target task is a 

work activity with evidence of significant potential for MSD 

risk factor exposure. Videotapes were made for each target task 

to aid in the analysis and brainstorming for ideas to improve 

how the task is performed. 

BRAINSTORMING 

The NIOSH team examined all available data to identify risk 

factors. This information was presented at brainstorming sessions to members of the mine work groups and technical staff. 

The aim was to discuss targeted work activities and identify 

health and safety issues, with emphasis on understanding the 

risk factors and discussing practical ideas to reduce risk factors 

in order to make the activities less physically demanding. 

Following the mine brainstorming sessions, a session was 

held with a diverse group of PRL researchers. Videotapes were 

reviewed by the NIOSH team to trigger a discussion of possible 

risk factors and to review the findings of the mine site 

evaluation team. Special emphasis was placed on notes taken 

from the brainstorming sessions conducted at the mine site. The 

aim was to examine the key issues identified and further develop 

or add to the ideas to improve how the target work tasks are 

performed. The risk factors identified and general ideas for job 

improvement were discussed at the closeout meeting held with 

representatives of each mine. 

Ideas for improvement were presented as a listing of all ideas 

generated during brainstorming sessions and discussions with 

mine representatives. These lists were not presented in any 

particular order with regard to likelihood of successfully 

reducing risk factors or ease of implementation. 

RESULTS
 

Appendices F through I provide detailed results for each of 

the four mine sites, respectively. This section provides a set 

of tables summarizing findings within and across each site. 

The tables focus on the seven common MSD risk factors 

discussed earlier. 

SELECTING WORK ACTIVITIES AND TASKS 

Table 1 describes the cooperating mine sites, baseline data 

used to profile MSD risk, and specific work activities/tasks 

identified for further study. The mines selected and studied 

varied with regard to commodity type, geographic location, 

workforce size, and mining methods. 

Work tasks were selected based on the baseline data 

gathered at each site. Results from the analysis of the baseline 

data were summarized for each site. From table 1, it should 

be noted that the definition of an incident and the methods of 

tracking incidents varied for each site. Sites reporting nearmisses, property damage, and minor cuts and scrapes10

10This is a good practice as it brings early attention to potential areas of 

concern. Thus, small problems can remain small problems. 

would 

normally yield significantly more incidents. 

MSD RISK FACTORS FOR SELECTED 

WORK TASKS
 

Once work tasks were identified, the NIOSH team interviewed those performing the tasks and made observations and 

measurements to identify specific MSD risk factors. These 

risk factors are cataloged in tables 2 through 5. 
 

 

8 

Table 1.—Mine descriptions, tools used to select tasks, and tasks selected across the four sites 

Mines selected 

Underground coal Surface copper Surface phosphate Underground limestone 

• Eastern United States 

• Room-and-pillar 

• 44- to 56-in seam height 

• 126 employees:

 118 – mine

 8 – surface 

• Southwestern United States 

• Open-pit operation with

 electrowinning and

 electrorefining 

• 736 employees:

 214 – mine

 522 – processing 

• Southern United States 

• Open-pit operation that

 pumps slurry to a

 cleaning plant 

• 307 employees:

 146 – mine

 161 – processing and

 maintenance 

• Eastern United States 

• Underground room­

 and-pillar quarry with

 a processing plant 

• 43 employees:

 29 – mine

 14 – processing 

BASELINE DATA TO PROFILE MSD RISK 

Incident data1 203 records 460 records 165 records 17 records 

Nordic 

Questionnaire 

Not used2 507 responses (shoulders, 

upper back, and neck were 

most often reported) 

50 responses (neck, knees, 

and shoulders were most 

often reported) 

40 responses (low back, 

neck, wrists, elbows, and 

hands were most often 

reported) 

Front-line 

supervisor 

interviews 

Not used2 55 interviews – 5 tasks rated 

high as very physically 

demanding 

8 interviews – 2 tasks rated 

high as very physically 

demanding 

3 interviews – 3 tasks 

rated high as very 

physically demanding 

TASKS SELECTED FROM THE BASELINE DATA AND CONCERNS IDENTIFIED BY MANAGEMENT 

• Supply delivery

 Motormen 

• Roof bolter

 Bolt installation

 Manual materials

 handling 

• Remote-control continuous miner operator

 Cutting coal (remotely) 

• Smelter operator

 Converter turnaround

 4B–5 gun rebuilds 

• Tank house operator

 Bar pulling

 Banding copper sheets 

• Refinery operator

 Cell checking 

• Dragline operator

 Operating dragline 

• Hydraulic pit station

 operator

 Operating pit station 

• Float crew

 Wrenching 

• Quality control

 technician

 Gathering samples

 Testing samples 

• Blasting crew

 Hand scaling

 Handling ANFO and

 dynamite 

• Scaling machine

 operator

 Operating scaling

 machine 

1

Information on the severity of injuries was not available; therefore, injury risk (rates) was not calculated. 2

The NIOSH team was very familiar with this mine, tasks, and work environment. This negated the need to interview supervisors and 

gather information via the Nordic Questionnaire from the general workforce. 
9 

Table 2.—Risk factors by observed tasks: underground coal mine 

Risk factors 

Tasks 

Supply delivery tasks Roof bolting tasks Continuous 

miner operation 

Motormen Motormen Motormen Roof bolter – Roof bolter – Cutting coal – 

delivering and collecting empty unloading small bolt installation manual mate­ remote-control 

receiving railcars railcars and 

loading refuse 

units of supplies rials handling continuous 

miner 

Prolonged, awkward postures Twisting and 

bending of torso 

more than 20° 

Extended 

forward reaches 

Flexing of the 

neck 

Twisting and 

bending of torso 

more than 20° 

Low roof conditions require 

kneeling or 

stooping during 

material 

handling 

Extended time 

spent in kneeling posture 

Awkward body 

postures – 

in particular, 

twisting of back 

and neck flexion 

near the back 

Forceful hand 

and arm exertions when 

bending bolts 

Repetitive 

extended 

forward reaches 

Repetitive control use 

Lifting and carrying supplies in 

bent or stooped 

postures 

Twisting and 

turning while 

handling 

supplies 

Working in 

cramped work 

space 

Constant load 

on neck and 

shoulders from 

8-lb control box 

Forceful exertions when lifting 

and moving 

power cable 

Extensive 

crawling 

Extended time 

spent in kneeling or stooped 

posture 

Arm or leg 

abduction when 

positioning cable 

Contact stress Low roof condi- Constant load 

(pressure points) tions require 

kneeling or 

stooping during 

material 

handling 

on neck and 

shoulders from 

8-lb control box 

Extensive 

crawling 

Jolting/Jarring Constant jarring 

from riding the 

rails 

Vibration exposure (hand/arm) 

Highly repetitive Repetitive Repetitive conmotions extended forward reaches 

Repetitive control use 

trol use 
10 

Table 3.—Risk factors by observed tasks: surface copper mine 

Risk factors 

Tasks 

Smelter Tank House Refinery 

Smelter operator –

converter turnaround 

Smelter operator – 

4B–5 gun rebuilds 

Tank house operator

– bar pulling 

Tank house operator

– banding copper

sheets 

Refinery operator –

cell checking 

Prolonged, awkward 

postures 

A lot of trunk twisting

while handling 4B–5 

guns 

Reaching for, pulling, and tossing

moderate to heavy

items 

Reaching into bins,

creating high forces

on the low back 

Asymmetric lifting

task with significant

trunk twisting 

Handling (lifting,

carrying, and positioning) of a 40-lb

banding tool 

Prolonged flexing of

the neck due to work 

with low targets 

Arms above shoulder 

height when raking

high nodules 

Forceful exertions 

(heavy or frequent

lifting) 

Lifting and placing 45-lb

guns to and from the

floor 

Repetitive forceful pushing and pulling with a

long bar to clean out

tuyere holes 

Reaching into bins,

creating high forces

on the low back 

Excessive pushing

and pulling forces to

position bin carts 

Variable amounts of 

force are required 

When working alone,

forceful exertions 

required 

Significant force

required to remove

larger nodules 

Hot environment 

Forceful gripping Extended use of unsupported jackhammer Variable amounts of 

force are required 

Contact stress 

(pressure points) 

Jolting/jarring 

Vibration exposure

(hand/arm) 

Extended use of unsupported jackhammer 

Highly repetitive

motions 

Repetitive forceful

pushing and pulling

with a long bar to clean

out tuyere holes 

Repetitive handling

of 45-point guns 

Highly repetitive task

– hundreds of bars 

per day 

Highly repetitive

upper-extremity

exertions 

Other Hot working environment, about 115 °F 

Table 4.—Risk factors by observed tasks: surface phosphate mine 

Risk factors 

Tasks 

Dragline operation Pit station operation 

(water cannons) Float crew 

Operating controls Operating controls Wrenching pipes 

Prolonged, awkward 

postures 

Awkward foot and ankles 

postures 

Extended time in seated posture 

Frequent twisting and turning of 

head and neck 

Awkward seated postures 

(on stools provided) 

Excessive neck extension when 

viewing pump monitors 

Extended time in seated posture 

Awkward postures during pipe 

assembly task 

Forceful exertions 

(heavy or frequent 

lifting) 

Handling heavy and awkward 

materials 

Forceful gripping 

Contact stress (pressure points) Forearm contact on edge of 

work stations 

Jolting/jarring Jolting/jarring while traveling 

over rough terrain in the maintenance truck 

Vibration exposure 

(hand/arm) 

Hand and arm vibration from air 

tool usage 

Highly repetitive 

motions 

Repetitive operation of foot 

pedals 

Repetitive use of joystick 

controls 

Repetitive/continuous use of joystick controls Repetitive hand and wrist 

movements 

Other Noise in operator's compartment Pinch-point exposure 
11 

Table 5.—Risk factors by observed tasks: underground limestone mine 

Risk factors 

Tasks 

Quality control technician Blasting crew Scaler operator 

Gathering samples Testing samples Hand scaling Handling ANFO 

and dynamite Operating scaler 

Prolonged, awkawkward postures Asymmetric load 

handling when 

carrying one bucket 

Ascending and 

descending steps 

while carrying loads 

Twisting, turning, 

and bending while 

handling sample 

pans 

Lifting loads above 

shoulders to dump 

Pulling trays and 

lifting loads from 

below knuckle 

height 

Extended forward 

reaches when 

cleaning face 

Working with arms 

above shoulder 

height 

Working below the 

feet to remove 

material 

Neck flexion when 

working with high 

and low targets 

Wrist flexion/extension when prying 

material 

Bending over, twisting, and reaching to 

lift ANFO in 50- b 

bags and dynamite 

in 55-lb boxes 

Loading ANFO into 

the hopper requires 

twisting and lifting 

with the elbow 

above shoulder 

The neck is flexed 

back when scaling 

the back (when 

scaling the back 

from the bench, 

you must lean forward to look up; 

the neck is not 

well supported) 

Forceful exertions Forceful exertions Forceful exertions Carrying awkward Pushing and pull­

(heavy or frequent with shoulders and with arms, shoul­ and heavy loads ing on controls 

lifting) back while 

shoveling 

Lifting and carrying 

heavy loads, 40- to 

70-lb buckets 

ders, and back; the 

8-ft-long pry bar 

creates a high force 

moment arm 

require frequent 

arm and shoulder 

exertions 

Jolting/jarring Constant bouncing 

and jarring while 

scaling 

Vibration exposure 

(hand/arm) 

Highly repetitive 

motions 

Repetitive control 

usage 

Other Ascending and 

descending steps 

with hands 

occupied 

Dust in the lab 

when analyzing a 

sample 

Environment can be 

noisy, dark, smoky, 

foggy, and humid 

SUMMARY
 

This study focused on identifying MSD risk factors using qualitative and quantitative data. The tools used to assess work tasks 

were effective for quickly identifying risk factors. Brainstorming 

sessions made workers more aware of risk factor significance. 

There were some obvious similarities among the four sites. 

Observations of work tasks and interviews with workers performing those tasks suggested that handling heavy and awkward 

objects, forceful arm and shoulder exertions, and working in 

cumbersome postures were common to all four sites. Tasks requiring a significant amount of manual work involving upper 

extremity and low-back activity were found at each site. Tables 

2 through 5 indicate that awkward postures and forceful exertions are the most common MSD risk factors observed within 

and across the four sites. 

Based on the task analysis, short brainstorming sessions were 

held with a cross-section of mine site personnel who had a stake 

in the task. These sessions were very useful as they generated 

ideas to reduce risk factors—or make the work process less 

physically demanding and less difficult. The sessions also offered an opportunity for the NIOSH team to meet with workers 

and offer comments and feedback on their work process and 

methods. Discussions were aided by the use of videotapes of 

workers performing the target tasks. In some cases, workers 

were surprised at the amount and extent of bending and twisting 

while handling heavy objects. 

This project ended with a report to mine management. It was 

up to the mine to follow up and consider the next step— 

implementation or experimentation with some of the ideas 

generated. Consequently, it is difficult to assess the ultimate 

value of the ideas generated and any impact that they might 

have on reducing risk factors. Logical next steps include: 
12 

1. Obtaining approval from management to further explore 

the ideas generated during the brainstorming. If approved by 

management, the task is to identify resources that would be 

needed to implement certain ideas to reduce the exposure level 

or duration of identified risk factors. Examples include 

(a) getting feedback from the workers on the ideas generated, 

(b) talking with suppliers about where parts or equipment may 

be purchased, (c) talking with maintenance personnel to see if 

a solution can be fabricated in-house, and (d) finding out how 

other mine sites may have dealt with similar issues. 

2. Identifying measures to assess the value of the proposed 

intervention(s) in reducing risk factor exposure levels or duration. Examples include (a) reducing the amount of weight lifted 

or handled, (b) reducing the number of times a task is performed, (c) reducing the amount of time needed to complete a 

task, (d) reducing force needed to activate a control, and 

(e) reducing the time spent in an awkward posture. 

There are several ways of dealing with risk factors. These 

include combinations of engineering changes, improved work 

practices, and increased use of personal protective equipment. 

Risk factor awareness along with a proactive culture, skills, and 

motivation to "problem solve" the process also offer interesting 

solution sets, such as job rotation, a change in routine, or the 

need for extra help. There is often more than one way to solve 

a problem, and those who do the job typically have the best 

understanding of the problems. This was the main motive for 

talking with workers and others (who had a stake in the job) at 

each of the sites, which led to discussion of how MSD risk 

could be reduced for specific tasks. 

The focus for job improvement should be on changes to work 

practices, better tool usage, or the use of new tools. Examples 

include (1) copper mine – methods changes for converter 

turnaround to make the task less physically demanding; 

(2) limestone mine – more frequent bucket moves and the use of 

a new scaling tool to limit the level of heavy work done in 

preparing the face for loading explosives; and (3) phosphate 

mine – better organization of the tools carried on the mechanic's 

pickup trucks to make the task of wrenching less difficult and 

more predictable. In each of these examples, there should be 

some long-term benefit in reducing the risk of sprains and 

strains and "caught between/struck by" injuries. Task analysis 

results indicated that handling heavy and awkward objects, 

forceful arm and shoulder exertions, and working in awkward 

postures were common to the four sites. This knowledge indicated a need for assist devices to help reduce manual tasks and 

for workers to learn more about common ergonomic risk factors 

and how to lessen or avoid them. 

Formal training and education (e.g., identifying risk factors) 

is one way to begin to integrate the science of ergonomics into 

worklife. The objective would be to help mining personnel become better at solving problems related to MSD injury risk. The 

outcome is a more skilled workforce—more knowledgeable of 

risk factors that can impede both production and safety. This 

can help with longer-term organizational goals to reduce cost 

and improve worker safety. 

REFERENCES
 

Cohen AL, Gjessing CC, Fine LJ, Bernard BP, McGlothlin JD [1997]. 

Elements of ergonomics programs: a primer based on workplace evaluations of 

musculoskeletal disorders. Cincinnati, OH: U.S. Department of Health and 

Human Services, Public Health Service, Centers for Disease Control and 

Prevention, National Institute for Occupational Safety and Health, DHHS 

(NIOSH) Publication No. 97–117. 

Cornelius KM, Turin FC, Wiehagen WJ, Gallagher S [2001]. An approach 

to identify jobs for ergonomic analysis. In: Proceedings of the IIE Annual 

Research Conference. Norcross, GA: Institute of Industrial Engineers. 

Fotta B, Bockosh GR [2000]. The aging workforce: an emerging issue in 

the mining industry. In: Bockosh GR, Karmis M, Langton J, McCarter MK, 

Rowe B, eds. Proceedings of the 31st Annual Institute of Mining Health, Safety 

and Research. Blacksburg, VA: Virginia Polytechnic Institute and State 

University, Department of Mining and Minerals Engineering, pp. 33–45. 

Hagberg M, Silverstein B, Wells R, Smith MJ, Hendrick HW, Carayon P, 

et al. [1995]. Work related musculoskeletal disorders (WMSDs): a reference 

book for prevention. Bristol, PA: Taylor and Francis, Inc. 

Hagglund G [1998]. The effect of age, occupation and experience on 

performance. In: Proceedings of the Global Ergonomics Conference (Cape 

Town, Republic of South Africa, Sept. 8–11, 1998). Amsterdam, Netherlands: 

Elsevier, pp. 239–249. 

Kumar S [2001]. Theories of musculoskeletal causation. Ergonomics 

44(1):17–47. 

Kuorinka I, Jonsson B, Kilborn A, Vinterberg H, Biering-Sorensen F, 

Anderson G, et al. [1987]. Standardized nordic questionnaire for the analysis 

of musculoskeletal symptoms. Appl Ergon 18:233–237. 

Scharf T, Vaught C, Kidd P, Steiner LJ, Kowalski KM, Wiehagen WJ, et al. 

[2001]. Toward a typology of dynamic and hazardous work environments. 

Hum Ecol Risk Assess 7(7):1827–1841. 

Steiner LJ, Cornelius KM, Turin FC [1999]. Predicting system interactions 

in the design process. Am J Ind Med Sep(Suppl 1):58–60. 

Stobbe TJ, Bobick TG [1986]. Musculoskeletal injuries in underground 

mining. Ann ACGIH 14:71–76. 

U.S. Bureau of Labor Statistics [1991]. Occupational injuries and illnesses 

in the United States by industry, 1989. Washington, DC: U.S. Department of 

Labor, Bureau of Labor Statistics, Bulletin 2379. 

Washington State Department of Labor [1994]. Fitting the job to the 

worker: an ergonomics program guideline. Olympia, WA: State of 

Washington Department of Labor, Division of Labor and Industries, 

Division of Consultation and Compliance Services, Workplace Consultation 

Program. 

Westgaard RH, Winkel J [1997]. Ergonomic intervention research for 

improved musculoskeletal health: a critical review. Int J Ind Ergon 20:463–500. 

Winn F, Biersner R, Morrissey S [1996]. Exposure probabilities to 

ergonomic hazards among miners. Int J Ind Ergon 18:417–422. 

Zhuang Z, Groce D [1995]. The national occupational health survey of 

mining: magnitude of potential exposures to musculoskeletal overload 

conditions. In: Bittner AC, Champney PC, eds. Advances in Industrial 

Ergonomics and Safety VII. London: Taylor and Francis, pp. 273–280. 
13 

APPENDIX A.—ERGONOMIC INTERVENTIONS FOR THE MINING INDUSTRY:
 

AN OVERVIEW OF PLANNED APPROACH
 

What:	 A NIOSH collaborative field research project to study ergonomics risk factors at a variety of 

mining operations. 

Objectives: (1) Assess ergonomic risk factors with emphasis on musculoskeletal disorders (MSDs). 

(2) Evaluate the effectiveness of interventions in terms of lowering risk factor exposures and 

reducing injuries. 

Cooperators: The most important cooperators will be participating mine companies. MSHA has a 

nonregulatory, technical interest in this project. MSHA’s interests include (1) learning more about MSD risk 

factors that mine workers are exposed to, (2) identifying the types of intervention strategies that are appropriate 

for mining environments, and (3) disseminating the general findings of this research throughout the mining 

industry. However, MSHA personnel will not be taking part in the collection and analysis of the data for this 

study. 

Why: The dynamic nature of mining environments exposes workers to a number of injury risk factors. 

Commonly encountered risk factors that can lead to the development of MSDs include heavy lifting, repetitive 

materials handling, awkward postures, and uneven walking surfaces. There is evidence that ergonomics 

interventions can help to lower the occurrence of MSDs in a variety of work settings. According to a 1997 

U.S. General Accounting Office study of five private sector ergonomics programs, the reduction in the number 

of reported injuries and illnesses ranged from 2.4 to 6.1 per 100 full-time workers. 

How: A two-phase effort in which objective 1 will be addressed in phase 1 and objectives 1 and 2 will be 

addressed in phase 2. 

Phase 1 will be concerned with gathering MSD health and safety baseline data and identifying general ideas 

for reducing risk factors. The goal is to visit four mine sites: underground coal (lower seam), underground 

nonmetal, surface metal, and surface nonmetal. At each mine, the following protocol is planned: 

(1) Hold introductory meeting with management and workforce representatives. 

(2) Establish safety and health baseline data using mine injury records, a musculoskeletal discomfort 

questionnaire, and supervisor interviews. 

(3) Use baseline data to develop risk factor assessment plan. 

(4) Collect MSD exposure data via worker interviews and job analysis. 

(5) Analyze and interpret MSD exposure data. 

(6) Prepare report of findings that identifies general ways to reduce risk factor exposures. 

(7) Conduct final meeting to present findings to management and workforce representatives. 
14 

Expected phase 1 duration: four mine visits within a 6- to 12-week period. 

Phase 2 will involve development, implementation, and evaluation of mine-specific ergonomics interventions. 

It will require long-term cooperation of one or two mine sites, which may or may not be sites that participated 

in phase 1. Expected duration: 3 to 4 years with many mine site visits. 

Protocol: 

(1) Conducted introductory meeting and site walk-through with management and workforce representatives. 

(2) Established safety and health baseline data using MSHA 30 CFR 50 data, mine injury records, and a 

general discomfort questionnaire. 

(3) Used baseline data to develop exposure assessment plans: 

(a) Prioritized jobs based on evidence of risk. 

(b) Chose jobs with significant risk for further analysis. 

(c) Selected tools for MSD exposure measurement. 

(4) Collected exposure data via mine site interviews and task analysis. 

(5) Analyzed and interpreted MSD exposure data. 

(6) Prepared report of findings that identified risk factors and general ideas to reduce risk factor exposures at 

that particular mine site. 

(7) Conducted final meeting to present findings to management and workforce representatives. 
APPENDIX B.—NORDIC QUESTIONNAIRE 

NIOSH Ergonomics Initiative

Musculoskeletal Discomfort Survey

The purpose of the survey:

You have been selected to participate in a National Institute for Occupational Safety and Health (NIOSH) study of 

pain in the mining industry. We are hoping to detennine what musculoskeletal risk factors exist at this mine and a

industry. We are interested in the type and location of the pain/discomfort symptoms you may be experiencing. T

take no more than 5 minutes to complete. Thank you for your cooperation.

How to answer the questionnaire:

Picture: In this picture you can see the approximate position of the parts of the body referred to in the questionnai

sharply defined, and certain parts overlap. You should decide for yourself in which part you have or have had your 

Table: Please answer by putting an "X" in the appropriate box - one "X" for each question. You may be in doubt a

but please do your best anyway. Note that colunm 1 of the questionnaire is to be answered even if you have never h

part of your body, coluIIll1s 2 and 3 are to be answered if you answered yes in colunm 1.
16 
17 

APPENDIX C.—FRONT-LINE SUPERVISOR INTERVIEW GUIDE 

I am part of a NIOSH research team that is working on a small study to evaluating physical risk factors 

at this mine. In particular, we want to obtain information about the causes of musculoskeletal pain. 

What we mean by “musculoskeletal pain” is pain that may result in injuries that are commonly referred 

to as “sprains” or “strains.” 

I would like to spend a few minutes to interview you about work activities in the area or group that you 

supervise. Our team plans to select three or four work activities for a final analysis, and we need your 

help. This interview should take about 20 minutes. 

Mine: ___ Interviewer:_____________________ Date ____/____/____ 

Initial of first name: __ Initial of last name: __ 

Last 4 digits of social security number: __ __ __ __ 

Title:_____________________________ Work location:_____________________________ 

How long have you been doing this job? _____years _____months 

Shift information: 

Shifts worked in this area: ______________________________ Do you rotate shifts? Y N 

If yes, describe the shift rotation sequence:
 

 

Supervisory responsibility: Number of employees supervised: ____________ 

Are these employees part of a work crew (like a production crew)? Y N 

Do you supervise the same people day in and day out? Y N 

Do you supervise the same job classifications day in and day out? Y N 
18 

Information about the work crew/group:
 

Please describe the jobs, title, and brief description performed by your work crew/group:
 

1. 

For these jobs, which ones seem to be the most physically demanding? Why? 
19 

Are there any tasks or activities within these jobs that are especially difficult or physically 

demanding? 

(Probe for specific factors – environmental factors like heat, humidity, dust, noise ... Or awkward 

postures ... Or handling heavy loads... Or types of tools or equipment used ... Or repetitious work.... 

Or pressures to get the job done... etc.) 

Is there anything else about the work done in your area that you think is relevant? 
20 

APPENDIX D.—BODY PART DISCOMFORT INTERVIEW GUIDE 

 

22 

APPENDIX E.—SAMPLE DECISION MATRIX 

Mine incident data, Nordic Questionnaire responses, and 

supervisor interviews were used to construct a decision matrix 

for identifying work groups appropriate for further evaluation. 

For each source of data, a subjective ranking of "low," 

"medium," or "high" was given by consensus of the NIOSH 

evaluation team. Each ranking for a work group was relative to 

other groups at the site. A ranking of "high" would not indicate 

a high risk level for injury; it would indicate that the comparison 

measure(s) for the given data type was high when compared to 

other work groups at that site. 

For each work group, an incident ratio was calculated to 

provide a relative estimate of incident risk. A work group incident ratio significantly above the site-wide incident ratio was 

given a "high" rating. A work group incident ratio significantly 

below the site-wide incident ratio was given a "low" rating. 

Work group discomfort was evaluated by comparing the 

number of body parts reported and the number of reports of 

discomfort for similar body parts. Work groups reporting higher 

than the site-wide average numbers of body parts and high percentages of workers with discomfort for a body part(s) were 

given a "high" rating. Work groups reporting lower than the 

site-wide average numbers of body parts and low percentages of 

workers with discomfort for a body part(s) were given a "low" 

rating. 

If a supervisor identified a work group as having physically 

demanding work, it was considered for a "high" or "medium" 

rating. Supervisor comments were evaluated for key characteristics of physical stress. The degree of physical stress was based 

on common physical risk factors, which include forceful 

exertions, heavy lifting, awkward postures, repetitive motions, 

and jolting or jarring. If any single or combination of risk factors was described to exist at a significant level, a rating of 

"high" was given. Work groups not identified by a supervisor 

were given a "low" rating. 

For scoring purposes, a rating of "high" was given 3 points, 

"medium" was given 2 points, and "low" was given 1 point. 

One additional point was awarded if management expressed 

concern regarding a particular work group. Work groups having 

the highest scores were deemed suitable for further evaluation. 

Cornelius et al. [2001] provide a more detailed discussion of 

how the decision matrix can be used to identify jobs that could 

be suitable for ergonomic evaluation. Table E–1 shows a 

sample decision matrix. 

Table E–1.—Sample decision matrix 

Work group No. of 

employees 

Incident 

data 

Nordic 

Questionnaire 

Supervisor 

interviews 

Management 

concern 

Final 

score 

Supervisors ............... 

Haul truck operators ......... 

4 

15 

Low 

Medium 

High 

Medium 

Low 

Low Yes 

5 

6 

Driller operators ............ 5 Medium Low Low 4 

Blasting crew . . . . . . . . . . . . . . 

High-lift/loader operators ..... 

4 

4 

High 

Medium 

High 

Medium 

High 

Medium 

Yes 10 

6 

Mechanics ................ 

Water truck operator ......... 

4 

1 

High 

Low 

High 

High 

High 

Low 

9 

5 

Laborers .................. 

Welders . . . . . . . . . . . . . . . . . . 

2 

3 

Low 

Low 

High 

Medium 

High 

Medium 

Yes 8 

4 
 

 

 

23 

APPENDIX F.—UNDERGROUND COAL MINE
 

This mine is an underground bituminous coal operation in 

the Eastern United States with 126 employees. Work activities 

include advance-and-retreat continuous mining using mainly 

shuttle cars and remote-control continuous mining machines. 

Seam height ranged from 44 to 56 in. 

The evaluation plan consisted of four steps. The first step 

was to use mine injury records and a list of management 

concerns to select work groups that had significant evidence of 

MSD risk factors. The NIOSH evaluation team members were 

very familiar with underground coal mine work activities, and 

several members were familiar with this particular mine site. 

For this reason, supervisor interviews and Nordic Questionnaires were not used. The five work groups chosen for evaluation were supply/delivery personnel, roof bolting machine 

operators, continuous mining machine (CMM) operators, shuttle 

car operators, and foremen/mine examiners. 

The second step was to use work task observation data, comments from the mine management team, and responses to the 

Body Part Discomfort Interview Guide to select target tasks for 

final evaluation. Supply motormen had three target tasks: 

delivering railcars to section side tracks, unloading supplies 

from railcars, and loading refuse onto motor cars. The target 

task for the supply yard was the retrieval of garbage and recyclable items from railcars by high-lift operators. Target tasks 

for roof bolter operators were installing roof bolts and retrieving 

supplies. The target task for CMM operators was using the machine to cut coal. The target task for shuttle car operators was 

transporting coal. Target tasks for foreman/mine examiners 

were walking throughout the mine and materials handling. 

The third step was to use tailored task analysis to characterize the ergonomic risk factors and musculoskeletal symptoms 

that exist for target tasks. The final step was to discuss the ergonomic risk factors for each target task with mine management 

and the workers who perform the tasks to identify ways to 

reduce risk factor exposures. 

INCIDENT DATA 

The mine provided 3 years of incident data from January 1, 

1996, to December 31, 1998. These included (1) lost-time 

injuries, (2) medical treatment, and (3) workmen's compensation 

claim data. Incident data were compiled and summarized by the 

NIOSH team. A total of 203 records were obtained. Data were 

categorized by occupation. Table F-1 summarizes these 

incidents by occupational class. CMM operators and scoop 

operators had the highest reported incident rate. 

Table F–1.—Underground coal: number of incidents and 

employeesby job title and incident rate, 1996–1998 

Average 

Occupation Incidents Employees annual 

incident rate1 

Continuous miner

 operators ........... 18 6 1.0 

Scoop operators ....... 

Supply clerks ......... 

18 

7 

6 

4 

1.0 

0.58 

Foremen . . . . . . . . . . . . . 52 30 0.58 

Mechanics ........... 23 16 0.48 

Roof bolter operators . . . 

Shuttle car operators . . . 

34 

22 

24 

18 

0.48 

0.47 

General laborers ....... 9 22 0.14 

Unknown occupations . . 20 NA NA

 Total . . . . . . . . . . . . . . 203 126 NA

 NA Not available. 

1

Average annual incident rate = reported incidents divided by estimated number of employees divided by 3 years. 

Table F–2 summarizes the 203 incidents by occupational 

class and incident type. Each incident record was reviewed and 

classified as one of six types: (1) slip/fall, (2) caught between/struck by, (3) strain/sprain, (4) burn, (5) other, or (6) unknown. Strain/sprain was split into subtypes of overexertion, 

awkward posture, and jarred/bounced/vibrated. The two most 

common incident types were "caught between/struck by" and 

strain/sprain. They were common to each of the occupational 

classes. Of the 203 reported incidents, 92 (45%) were "caught 

between/struck by" incidents and 77 (38%) were sprains/strains. 

TASK-SPECIFIC RESULTS 

Tables F–3 to F–6 summarize information gathered for the 

specific tasks studied at the underground coal mine. Ideas to 

reduce risk factors were developed based on brainstorming 

sessions with those who had a stake in the task, i.e., those who 

performed the task, supervisors, safety representatives, and engineering and maintenance staff. NIOSH personnel facilitated the 

brainstorming sessions. It should be noted that all ideas generated 

during brainstorming are listed. The ideas for improvement are 

not listed in any particular order with regard to likelihood of 

successfully reducing risk factor exposure or ease of 

implementation. These ideas are unique to this mine site and the 

tasks observed and should not be generalized to all mine sites. 
24 

Table F–2.—Underground coal: incidents by occupational class and incident type, 1996–1998 

Incident type 

Continuous 

mining

machine 

operators 

Foremen 

Supply 

and 

laborers 

Roof 

bolter 

operators 

Scoop and

shuttle car 

operators

Mechanics Unknown Total 

Slip/fall . . . . . . . . . . . . . . . . . . . . . . . . 8 1 2 2 1 3 17 

Caught between and struck by ...... 10 23 9 12 13 11 14 92 

Strain/sprain:

 Overexertion . . . . . . . . . . . . . . . . . . 3 8 4 6 14 8 2 45

 Awkward posture . . . . . . . . . . . . . . . 2 8 1 11 4 26

 Jarred/bounced/v brated ......... 3 3 6 
 

Burn . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 1 3 
 

Other . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1 2 4 2 1 13 
 

Unknown . . . . . . . . . . . . . . . . . . . . . . . 1 1

 Total . . . . . . . . . . . . . . . . . . . . . . . 18 52 16 34 40 23 20 203 
 

Table F–3.—Underground coal: roof bolter operator – installing bolts and manual materials handling 

Target tasks Primary risk factors 

Installing roof bolts (N=24) • Awkward body postures, in particular: twisting of back, flexing the neck, and

 extended time spent in kneeling posture 

Operators drill holes in the mine roof and • Forceful work – hand and arm exertions when bending bolts 

install bolts. • Repetitive extended forward reaches 

• Repetitive control use 

Manual materials handling (N=24) • Lifting and carrying supplies in bent or stooped postures 

• Twisting and turning while handling supplies 

Operators must load and handle cable, • Forceful exertions when handling power cable 

resin, bolts, wrenches, and plates. • Extended time spent in awkward and cramped work space 

Part of the body affected: 

Discomfort surveys not done. From NIOSH observations of risk factors: back, shoulders, neck, knees, elbows, and wrists. 

Ideas for improvement 

• Use effective knee padding. Knee pads should allow for mobility; protect the knees from hard, uneven surfaces; and provide

 cushioning (such as a gel lining) where it contacts the knee cap. 

• Consider using folding seats attached to the roof bolting machine to get workers off of their knees and give them the oppor­

 tunity to vary their posture. 

• Use job rotation, which would prevent these workers from constantly being on their knees. 

• Better organize tool and supply trays on the bolting machines. It is important to ensure that there are no barriers in the path

 of handling materials. 

• Redesign control placement to improve operator positioning. 

• To aid in bolt bending, use a pipe mounted on the machine, which can be used to get leverage by placing one end of the bolt

 in the pipe. 

• Ensure that supplies are stored close to the machine and in manageable weights. 

• Supplies should be stored on the machine in an orderly fashion. This decreases the force required to pull out supplies from

 the bottom of a pile or to lift heavier materials to get to something else. 
25 

Table F–4.—Underground coal: continuous mine operator – cutting coal 

Target tasks Primary risk factors 

Cutting coal (N=6) • Contact stress – constant load on neck and shoulders from 8- b control box 

• Forceful exertions when lifting and moving power cable 

Miner operators were responsible for • Awkward postures – extensive crawling, extended time spent in kneeling or

remotely operating the machine that cuts stooped posture, and arm or leg abduction when positioning cable 

coal and loads it into shuttle cars. • Repetitive control use 

Part of the body affected: 

Discomfort surveys not done. From NIOSH observations of risk factors: back, neck, and knees. 

Ideas for improvement 

• Use a support device to stabilize control box and remove the weight from the neck. Operators can use several devices to help

 support the control box. An example is short chains (3–4 in) that can be hooked onto the miners' belt and onto the remotecontrol box. These chains allow the operator to "rest" the remote box by hanging the weight from the belt. Another support

 device is a "pogo stick." It is a single-legged pole (pole height can be changed for different seam heights) that screws onto

 the bottom of the remote box. The stick is balanced by the operator. 

• Use rugged knee pads with soft gel inner linings to help alleviate knee pain from kneeling. 

• Provide operators with a seat or stool to operate from to reduce knee and low back stress. Several continuous mining

 machine operators have used buckets with cushions to sit on. 

• Consider a reel device on the continuous miner to help position cable. 

• Get help when pulling on long lengths of cable. 

Table F–5.—Underground coal: shuttle car operator – transporting coal 

Target task Primary risk factors 

Transporting coal (N=18) 

Shuttle car operators are respons ble for 

hauling coal from the face area to the belt 

for transfer outside. 

• Considerable vibration and jarring 

• Awkward postures and cramped spaces 

• Forceful exertions when handling power cable 

Part of the body affected: 

Discomfort surveys not done. From NIOSH observations of risk factors: back and neck. 

Ideas for improvement 

• Replace the current foam-padded seating on shuttle cars with seats that use lab- and field-tested viscoelastic foams. 

Table F–6.—Underground coal: motormen – unloading supplies 

Target tasks Primary risk factors 

Motormen unloading small units of • Awkward postures: flexing of the neck, extended forward reaches, twisting and

supplies (N=6) bending of torso more than 20°, and low roof conditions require kneeling or

 stooping during material handling 

Most items are unloaded by scoop 

operators, but items such as cap wedge 

bundles and partial rock dust pallets are 

manually unloaded. 

Part of the body affected: 

Discomfort surveys not done. From NIOSH observations of risk factors: neck, shoulders, and back. 

Ideas for improvement 

• The manual handling of supplies should be reduced as much as poss ble. Aim to send all items underground on pallets. If

 there are materials currently delivered by the supplier in bundles that are too large to go underground, then work with sup­

 pliers so that acceptable bundle sizes can be acquired. Try to use frequent and open communication and more underground

 storing to avoid sending partial pallets underground. 

• Because communication is a problem, try to develop a better supply-tracking system. This would involve clearly defining the

 information needs of everyone involved in the supply delivery and receipt process. Then clearly establish a responsibility

 chain for keeping the tracking system up to date so that everyone in the process has current and relevant information. 
26 

APPENDIX G.—SURFACE COPPER MINE
 

This mine is a surface copper operation in the southwestern 

United States with more than 700 employees. The extensive 

operations include an open pit for copper ore extraction, leaching pads and ponds for collecting copper in solution, an electrowinning plant for plating nearly pure copper cathodes from 

solution, a smelting plant for producing copper anodes, an 

electrorefinery for breaking down copper anodes from the 

smelter into solution and plating nearly pure copper cathodes, 

and a rod plant to produce coils of copper rod. 

The evaluation plan consisted of four steps. The first step 

was to use mine incident records, the Nordic Questionnaire, 

supervisor interviews, and a list of management concerns to 

select work areas that have significant evidence of MSD risk 

factors. A decision matrix was developed using the results of an 

evaluation of the data. The three work areas selected for further 

evaluation were smelter operations, refinery operations, and 

tank house operations. The second step was to use work task 

observation data and comments from the mine management 

team to select target tasks for final evaluation. The four target 

tasks were converter turnaround and 4B–5 gun rebuilds at the 

smelter, bar pulling and banding at the tank house, and cell 

checking at the refinery. The third step was to use body part 

discomfort interviews and tailored task analysis to characterize 

the ergonomic risk factors and musculoskeletal symptoms that 

exist for target tasks. The final step was to conduct 

brainstorming sessions with workers who perform target tasks 

to discuss the ergonomic risk factors and to identify general 

ideas to reduce risk factor exposures. 

A brief overview of the baseline data, a copy of the decision 

matrix, risk factors identified, and general ideas for task improvement are presented below. 

INCIDENT DATA 

The mine provided 3 years of incident data from January 1, 

1996, to December 31, 1998. These incidents involved (1) nearmisses, (2) medical treatment, and (3) lost work time. Incident 

data were summarized by the evaluation team. A total of 475 

records were obtained. 

Data were categorized by work area. To determine which 

work areas had higher incident rates, researchers obtained an 

estimated number of employees for each work area. Table G–1 

summarizes these incident rates. Incident rates for areas such as 

administration, land, and the warehouse were not calculated due 

to the small number of employees for each, but the injury types 

for these areas are included in table G–2. The highest reported 

incident rates occurred at smelter operations, smelter maintenance, and rod mill operations. Table G–2 summarizes the 

475 incidents by work area and incident type. Each incident 

record was reviewed and classified as one of six types: (1) burn, 

(2) slip/fall, (3) caught between/struck by, (4) strain/sprain, 

(5) other, or (6) unknown. The two most common incident 

types were "caught between/struck by" and strain/sprain. Of the 

475 incidents, 184 (39%) were "caught between/struck by" 

incidents. Nearly half of the "caught between/struck by" incidents occurred at the smelter. Workers in the smelter and the 

mine areas were found to have the most sprains and strains. 

Most strain/sprain injuries and many "caught between/struck 

by" injuries are indicators of MSD risk factors. 

Table G–1.—Surface copper: number of incidents and 

employees by work area and incident rate, 1996–1998 

Work area Incidents Employees Average annual

 incident rate1 

Mine operations ........ 

Mine maintenance ...... 

Refinery operations . . . . . 

Refinery maintenance .... 

Smelter operations ...... 

Smelter maintenance .... 

Rod mill operations ...... 

Rod mill maintenance .... 

Solution extraction (SX)

operations ........... 

Solution extraction (SX)

maintenance ......... 

Tank house operations . . . 

Tank house maintenance . 

 Total . . . . . . . . . . . . . . . 

70 

30 

32 

7 

144 

87 

32 

3 

22 

9 

13 

11 

460 

144 

70 

73 

22 

153 

96 

40 

12 

43 

21 

39 

23 

736 

0.16 

0.14 

0.15 

0.11 

0.31 

0.30 

0.27 

0.08 

0.17 

0.14 

0.11 

0.16

0.21
 

 1

Average annual incident rate = reported incidents divided by 

estimated number of employees divided by 3 years. 

NORDIC QUESTIONNAIRE 

Table G–3 shows body part discomfort data rated as "above 

average" or "below average" by work area. To be considered 

"above average," ratings had to be in the upper third of all 

ratings. Similarly, "below average" ratings were in the lower 

third of all body part discomfort ratings for a specific body part. 

If a body part does not appear in the table, it can be considered 

to have an "average" rating of discomfort. 

SUPERVISOR INTERVIEWS 

Fifty-one jobs were identified by supervisors as physically 

demanding—17 maintenance jobs and 34 operations jobs. Of 

the 34 operations jobs, 5 were given a "low" exposure rating, 

5 were given a "high" exposure rating, and 24 were given a 

"medium" rating. The five "high"-rated jobs were cell checking 

in the refinery, ISA tapping, converter turnarounds, smelter 

technicians, and bar pullers in the tank house. 

Of particular note are the exposure ratings for maintenance 

jobs. These jobs were the most difficult to rate. It was decided 

to rate them all as "medium." The rationale was that maintenance tasks may vary significantly each day. For each maintenance job identified, there was at least one associated task that 

could have been rated "high." Because this evaluation was to be 

for jobs as a whole, it was believed to be best to rate them all as 

"medium." 
27 

G–2.—Surface copper: incidents by work group and incident type, 1996–1998 

Incident type 

Work group Burn Slip/fall 

Caught 

between/ 

struck by 

Strain/ 

sprain Other Unknown Total 

Administration . . . . . . . . . . . . . . . . . . . . . . 4 1 5 

Land ............................. 2 2 

Mine maintenance .................. 7 14 8 1 30 

Mine operators ..................... 

Project services . . . . . . . . . . . . . . . . . . . . 

9 

1 

19 21 9 13 70 

1 

Quality control lab . . . . . . . . . . . . . . . . . . . 

Refinery maintenance ................ 

1 

1 

1 

2 3 1 

2 

7 

Refinery operators .................. 

Rod plant maintenance .............. 

3 

1 

3 15 

1 

10 

1 

1 32 

3 

Rod plant operators ................. 

Sample plant operators .............. 

5 1 18 

1 

5 2 1 32 

1 

Smelter maintenance ................ 8 10 37 21 3 8 87 

Smelter operators ................... 28 23 51 24 5 13 144 

Solution extraction (SX) maintenance . . . 

Solution extraction (SX) operators ...... 

2 

2 

2 

6 

3 

10 

2 

4 

9 

22 

Tank house maintenance ............. 1 4 2 3 1 11 

Tank house operators ................ 1 2 5 3 2 13 

Warehouse ........................ 1 1 

Other . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3

 Total . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 76 184 103 21 38 475 

Table G–3.—Surface copper: ratings of body part discomfort by work area 

Work area Above average ratings Below average ratings 

Smelter maintenance ................ Knees, ankles ............................. Neck, shoulder, low back. 

Smelter operators ................... 

Mine maintenance .................. 

None . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Hips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

None. 

Neck, wrist, low back, knee, ankle. 

Mine operators ..................... 

Rod plant maintenance .............. 

Upper back ............................... 

None . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

None. 

All. 

Rod plant operators ................. 

Tank house maintenance ............. 

Shoulders, e bows ......................... 

Shoulders, low back ........................ 

All. 

E bows, hips, knees, ankles. 

Tank house operators ................ 

Solution extraction (SX) maintenance . . . 

Shoulders, e bows, upper back, knees, ankles . . . 

Hips .................................... 

None. 

Low back, neck. 

Solution extraction (SX) operators ...... 

Refinery maintenance ................ 

Neck, shoulders, upper back, hips, ankles ....... 

Neck, shoulders, hips, knees ................. 

None. 

None. 

Refinery operators .................. Neck, upper back .......................... None. 

DECISION MATRIX 

Results of the decision matrix are shown in table G–4. The 

ranking procedure identified three areas with a score of 8 or 

higher: refinery operators (9), smelter operators (8), and tank 

house operators (8). 

BODY PART DISCOMFORT INTERVIEWS 

Body part discomfort interviews were conducted with 19 

workers who perform target tasks. The parts of the body most 

cited by converter turnaround workers were shoulder, elbow, 

wrist, midback, and low back. The average severity of reported 

pain was mild to moderate, but the frequency of pain was 

weekly or daily. This indicates that the pain is generally not too 

severe, but is experienced frequently in many parts of the body. 

It should be noted that no more than 5 out of the 11 converter 

turnaround workers reported pain in any one area of the body. 

Similarly, only one of three bar pullers reported mild, but 

frequent pain in the neck and low back. All four cell checkers 

reported pain in the neck, elbow, and low back. The most 

severe pain was reported for the elbow. 

TASK-SPECIFIC RESULTS 

Tables G–5 to G–8 summarize information gathered for the 

specific tasks studied at the surface copper mine. Ideas to 

reduce risk factors were developed based on brainstorming 

sessions with those who had a stake in the task, i.e., those who 

performed the task, supervisors, safety representatives, and 

engineering and maintenance staff. NIOSH personnel facilitated 

the brainstorming sessions. It should be noted that all ideas 

generated during brainstorming are listed. The ideas for 

improvement are not listed in any particular order with regard to 

likelihood of successfully reducing risk factor exposure or ease 

of implementation. These ideas are unique to this mine site and 

the tasks observed and should not be generalized to all 

mine sites. 
28 

Table G–4.—Surface copper: decision matrix for selecting tasks 

Work area No. of 

employees 

Incident 

data 

Nordic

 Questionnaire 

Supervisor 

interviews 

Management 

concern 

Final 

score 

Mine:

 Maintenance ....... 70 (10%) Medium Low Medium 5

 Operators . . . . . . . . . . 144 (20%) Medium Medium Medium 6 

Refinery:

 Maintenance ....... 22 (03%) Low High Medium 6

 Operators . . . . . . . . . . 73 (10%) Medium High High Yes 9 

Rod plant:

 Maintenance ....... 12 (02%) Low Low Medium 4

 Operators . . . . . . . . . . 40 (05%) High Low Medium 6 

Smelter:

 Maintenance ....... 96 (13%) High Medium Medium 7

 Operators . . . . . . . . . . 153 (21%) High Medium High Yes 9 

Solution extraction (SX):

 Maintenance ....... 21 (03%) Medium Medium Medium 6

 Operators . . . . . . . . . . 43 (06%) Medium High Medium 7 

Tank house:

 Maintenance ....... 23 (03%) Medium Medium Medium 6

 Operators . . . . . . . . . . 39 (05%) Low High High Yes 8 

Table G–5.—Surface copper: smelter operator – converter turnaround 

Target task Risk factors 

Converter turnaround (N=11) Primary risk factors: 

This task consisted of removing 4B–5 • Hot working environment, about 115 °F 

guns from the converter, identifying guns • Lifting and placing 45-lb guns to and from the floor 

requiring repair, cleaning out tuyere • A lot of trunk twisting while carrying and placing guns 

holes, and reinstalling 4B–5 guns. • Repetitive, forceful pushing and pulling to clean out holes 

• Extended use of an unsupported (29-lb) jackhammer 

Part of the body affected: 

Discomfort surveys were used. All 11 workers reported pain, with no more than 5 out of 11 respondents reporting pain in any 

particular area of the body. Average to moderate pain: shoulder, e bows, wrists, midback, and low back. Frequency of pain: 

weekly or daily. 

Ideas for improvement 

• Use a rack or cart to hold guns to reduce lifting, especially from the floor. The rack or cart could be positioned to reduce the

 distance that guns are carried. 

• Use a wheeled rack that can be maneuvered into place with guns, then wheeled out to rebuild. 

• Either suspend or support the jackhammer to reduce the amount of force required to position and hold the pneumatic hammer

 while cleaning the holes. 

• Explore replacing the jackhammer and bar with a mobile drill to clean holes. 

• Ensure that there is sufficient air movement to reduce nonradiant heat effects. If the source is radiant heat, control by blocking

 the heat source. 

Table G–6.—Surface copper: smelter operator – 4B–5 gun rebuild 

Target task Risk factors 

4B–5 gun rebuilds (N=1) 

This task consisted of moving, checking, lubricating, testing, and sometimes 

rebuilding 4B–5 guns. 

Primary risk factors: 

• Repetitive handling of 45-lb guns 

• Reaching into bins, creating high forces on the low back 

• Excessive pushing and pulling forces to position bin carts 

Part of the body affected: 

Discomfort survey was used. Worker reported pain in the elbows, hands, and knees. 

Ideas for improvement 

• Use a rack/cart to hold guns so that worker can test more than one gun at a time (set up in sequence). 

• Put the rebuild shop in the converter aisle and deliver guns in a rack/cart ready to be tested. 

• If using a rack to store and work on guns, the guns should be clamped in and racks blocked when testing. 

• Use a ratcheting tool with a better grip to remove O-rings. 
29 

Table G–7.—Surface copper: refinery operator – cell checking 

Target task Risk factors 

Cell checking (N=4) Primary risk factors: 

This task required workers to identify and • Highly repetitive upper-extremity exertions 

correct shorts in plating cells. Cell check­ • Significant force required to remove nodules 

ing requires workers to locate and knock • Hot environment 

off nodules on copper cathodes using a • Prolonged flexing of the neck due to work with low targets 

hand rake. • Awkward shoulder postures while raking 

Part of the body affected: 

Discomfort survey was used. All four workers reporting pain in neck, elbow, and low back. The most severe pain was reported 

for the elbow. 

Ideas for improvement 

• Consider a new power-assisted, spring-loaded, or laser-cutting tool. 

• Put a second handle on the bar to help with posture when removing higher nodules. 

• Use cushioned or dampening material on handles of rakes. 

• Develop a way to allow cell checkers to look forward instead of down while performing the task, e.g., use a mirror to display

 low targets. 

• When checking for shorts, mount the display meter higher or use an audible cue and an earplug. 

• Use footwear that will provide protection from the heat and offer antifatigue properties. 

• Use job rotation in the refinery. 

Table G–8.—Surface copper: tank house operator – bar pulling 

Target task Risk factors 

Bar pulling (N=3) Primary risk factors: 

This task required the worker to pull • Highly repetitive task – hundreds of bars per day 

hanger bars out of the loops attached to a • Variable amounts of force are required 

copper cathode. • When working alone, forceful exertions required 

• Asymmetric lifting task 

• Significant trunk twisting 

Part of the body affected: 

Discomfort surveys were used. One worker reported mild, but frequent pain in the neck and low back 

Ideas for improvement 

• The current bar-pulling task should be a two-person task. 

• Consider using an automated bar-pulling process like that observed at another mine. 

• Adjust the cathode tilt table and bar-receiving table to ensure good posture and minimal transfer distance. 

• Spring load the bar-receiving table. The table cannot be bolted down. It needs to be moved by the forklift when full. 

• Spray the bars with a lubricant. The bars used to be sprayed with oil, but this caused problems with the quality of the copper. 

• The banding tool could be suspended and counterweighted to allow for easier handling. 

• The banding tool could be mounted on a platform. The platform should be roughly the same height as the cathodes. 
 

 

 

 

30 

APPENDIX H.—SURFACE PHOSPHATE MINE
 

This mine is a surface phosphate operation in the Southern 

United States with 307 employees. The operations include a 

cleaning plant and five phosphate pits, each with a dragline, pit 

car, and dozer. Mining operations involve overburden removal, 

phosphate extraction, slurry pits, and pumping and piping slurry 

(referred to as "matrix") back to the plant. The cleaning plant 

removes impurities from the matrix and loads the phosphate into 

railcars for shipment to concentration plants. 

The evaluation plan consisted of three steps. The first step 

was to use mine incident records, the Nordic Questionnaire, 

supervisor interviews, and a list of management concerns to 

select work groups that have significant evidence of MSD risk 

factors. The evaluation team only had time to gather data for 

the following work groups: float crews, pit operators, dragline 

operators, and reagent operators. The second step was to use 

work task observation data and comments from the mine 

management team to select target tasks for more in-depth 

evaluation. The target tasks selected were wrenching and truck 

driving by float crews, operation of the hydraulic pit station, 

operation of the dragline, emptying reagent cars, and general 

dozer operation. The final step was to use body part discomfort 

interviews, video task analysis, and brainstorming sessions with 

mine workers to characterize the ergonomic risk factors and 

develop general risk reduction ideas. 

A brief overview of the baseline data, risk factors identified, 

and general ideas for task improvement are presented below. 

INCIDENT DATA 

The mine provided 3 years of incident data from January 1, 

1996, to December 31, 1998. A total of 165 records were 

obtained. Because of numerous reorganizations that occurred, 

incident rates were calculated based on the total number of 

employees as of January 1, 2000, rather than average numbers 

over the 3-year period. Table H–1 lists job titles, number of 

incidents, and incident rates. Table H–2 summarizes the 165 

incidents by occupational class and incident type. Each incident 

record was reviewed and classified as one of six types: (1) burn, 

(2) slip/fall, (3) caught between/struck by, (4) strain/sprain, 

(5) other, or (6) unknown. "Caught between/struck by" and 

"strain/sprain" were the incidents that occurred most frequently 

and accounted for over 50% of the total. 

Table H–1.—Surface phosphate: number of incidents and 

employees by job titleand incident rate, 1996–1998 

Job title Incidents Employees Average annual 

incident rate1 

Cleaning plant 

operators .......... 22 58 0.13 

Crane operators ...... 

Dozer operators ...... 

4 

2 

4 

13 

0.33 

0.05 

Dragline operators .... 

Electricians . . . . . . . . . . 

4 

5 

20 

18 

0.07 

0.09 

Environmental

 technicians . . . . . . . . 1 8 0.04 

Laborers ............ 7 43 0.05 

Mechanics/repairmen,

 mechanic helpers,

 welders . . . . . . . . . . . 54 45 0.40 

Pit operators ......... 

Wrenchers, truck 

1 16 0.02 

 drivers . . . . . . . . . . . . 28 25 0.37 

All other occupations . . 37 57 0.22

 Total . . . . . . . . . . . . 165 307 0.18 1

Average annual incident rate = reported incidents divided by estimated 

number of employees divided by 3 years. 

NORDIC QUESTIONNAIRE 

Table H–3 shows Nordic Questionnaire responses rated as 

"above average" or "below average" by work group. To be 

considered "above average," response percentages had to be at 

least 50% higher than the mine-wide percentage for reported 

discomfort for either the past year or the past week. Similarly, 

"below average" response percentages had to be at least 50% 

lower than the mine-wide percentage for reported discomfort for 

either the past year or the past week. If a body part does not 

appear in the table, it was considered to have an "average" rating 

of reported discomfort. The low number of respondents (50) 

weakens inferences about reported body part discomfort. The 

results were most useful for those work groups with a larger 

number of respondents, i.e., the preparation plant and the pit 

crew. 

SUPERVISOR INTERVIEWS 

This mine utilizes supervisors for the float crews (float 

supervisor), dragline pits (area supervisor), and flotation plant 

(shift leader). All of these positions can be held by a regular 

supervisor or a "step-up" supervisor, which is a laborer who has 

been temporarily "stepped up" into the supervisory position. 

These employees have a dual role. They perform work group 

coordination and regular job duties. About 35% of the 

supervisors interviewed during all field visits were "step-up" 

supervisors. 

Twelve jobs were identified as physically demanding—seven 

in the mine and five in the plant. Of the seven mine jobs, three 

were given a "low" exposure rating, two were given a "high" 

exposure rating, and two were given a "medium" exposure 

rating. Of the five plant jobs, three were given a "low" rating 

and two were given a "medium" rating. Determination of degree 

of physical stress was predicated on description of common 

physical risk factors, which include forceful exertions, awkward 

postures, repetitive motions, duration of exposure, contact 

stresses, vibration, or combinations of these factors. Table H–4 

lists key responses of supervisors for jobs given a "high" or 

"medium" rating by the NIOSH evaluation team. 
 

31 

Table H–2.—Surface phosphate: incidents by job title and incident type, 1996–1998 

Incident type 

Job title 

Burn Slip/fall 

Caught 

between/ 

struck by 

Strain/ 

sprain Other Unknown Total 

Cleaning plant operators ........................ 8 5 2 7 22 

Crane operators ............................... 1 1 2 4 

Dozer operators ............................... 1 1 2 

Dragline operators ............................. 3 1 4 

Electricians . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1 2 5 

Environmental technicians . . . . . . . . . . . . . . . . . . . . . . . 1 1 

Laborers ..................................... 2 2 2 1 7 

Mechanics/repairmen, mechanic helpers, welders .... 3 2 24 12 13 54 

Pit operators .................................. 1 1 

Wrenchers, truck drivers ........................ 2 9 7 7 3 28 

Other/unknown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 5 9 10 7 5 37

 Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 24 51 36 39 9 165 

Table H–3.—Surface phosphate: ratings of body part discomfort by work area 

Work group Employees Above average ratings Below average ratings 

Preparation plant . . . 

Pit crew . . . . . . . . . . . 

23 

13 

Ankles/feet, knees .................... 

Neck, shoulders ...................... 

E bows. 

None. 

Administrative . . . . . . 

Maintenance ....... 

7 

3 

Neck, elbows, lower back . . . . . . . . . . . . . . . 

Shoulders, e bows, upper back, hips/thighs,

Knees and upper back. 

Ankles/feet. 

knees. 

Other . . . . . . . . . . . . . 3 None . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Shoulders, elbows, wrists/hands, upper

Float crew . . . . . . . . . 1 None . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

back, hips/thighs, knees, ankles/feet. 

None. 

Table H–4.—Surface phosphate: physically demanding jobs identified by supervisors 

Work area Physically demanding job Key comments Rating 

Mine 

Mine

.... 

.... 

Wrencher – moves, rolls, connects, and main-

 tains pipe, pit moves, move power cables. 

Laborer – probationary period, same tasks as

 wrencher. 

Wrenching bolts is hard on back because of awk-

 ward positions and heavy tools; poor footing in

 muddy, uneven terrain. Exposed to pinch points. 

Same as wrencher . . . . . . . . . . . . . . . . . . . . . . . . . 

High. 

High. 

Mine 

Mine 

Plant 

.... 

.... 

.... 

Truck driver – drives float crew truck, handles

 bolts and supplies. 

Pit station operator – operates hydraulic

 cannons. 

Spiral operator (and assistant) – takes care of

 spirals. 

Mentally more demanding, does some wrenching;

 pulling air hose is sometimes difficult. 

Sits a lot, requires constant hand movements to

 manipulate cannons. 

Physical work cleaning spirals with steel wool, vol-

 ume of work and number of spirals, stand on feet,

 constant motion. 

Medium. 

Medium. 

Medium. 

Plant .... Waste system operator – maintains spillways . . Lifting of heavy boards in and out of truck and at

 spillway. 

Medium. 

BODY PART DISCOMFORT INTERVIEWS 

NIOSH researchers interviewed 26 wrenchers/truck drivers, 

7 dragline operators, 3 pit operators, 4 dozer operators, and 

2 reagent operators. The parts of the body with discomfort most 

cited by workers performing wrenching tasks were low back, 

wrists, and shoulders. The average pain severity was mild to 

moderate, and the average frequency of pain was monthly. 

Results for the wrenching task indicate that the pain is generally 

not too severe, but is experienced frequently in many parts of 

the body. Results for dragline operators are more dispersed, 

with no one body part being cited by the majority of operators. 

Average discomfort was mild to moderate. However, the 

average frequency was cited as weekly to daily. Of the four 

dozer operators, all reported neck and low back pain; the pain 

severity was on average mild, but occurred weekly. Among the 

three workers operating the pit station, all indicated that they 

had shoulder pain. The pain severity was mild to moderate and 

occurred almost weekly. Finally, the two reagent operators reported neck, shoulder, wrist, hands, back, and knee discomfort. 

This discomfort was mild to moderate, but was experienced 

daily. 
32 

TASK-SPECIFIC RESULTS 

Tables H–5 to H–8 summarize information gathered for the 

specific tasks studied at the surface phosphate mine. Ideas to 

reduce risk factors were developed based on brainstorming 

sessions with those who had a stake in the task, i.e., those who 

performed the task, supervisors, safety representatives, and 

engineering and maintenance staff. NIOSH personnel facilitated 

the brainstorming sessions. It should be noted that all ideas 

generated during brainstorming are listed. The ideas for 

improvement are not listed in any particular order with regard to 

likelihood of successfully reducing risk factor exposure or ease of 

implementation. These ideas are unique to this mine site and the 

tasks observed and should not be generalized to all mine sites. 

Table H–5.—Surface phosphate: float crew – wrenching pipes 

Target task Risk factors 

Wrenching task (N=26) Primary risk factors: 

The float crew is responsible for most • Handling of heavy and awkward materials 

aspects of pipe maintenance and pipe • Repetitive hand and wrist movements 

relocation from one area of the mine to • Hand and arm v bration from air tool usage 

another. • Awkward postures during pipe assembly tasks 

• Pinch-point exposures 

Part of the body affected: 

Discomfort surveys were used. Workers cited low back, wrists, and shoulders. Pain was mild to moderate. Frequency of pain 

was monthly. 

Ideas for improvement 

• Standardize trucks, preferably a large size, which will provide more comfort for the crew while traveling the site and will allow

 for a more consistent set of tools and supplies to be available. 

• Standardize equipment (wrenches, bars, air guns, etc.), and keep these on each float crew truck. 

• Make pneumatic wrenches available to all float crews. 

• Supply wrenchers with personal protective equipment such as impact gloves, knee pads, and extra-large rain suits that will

 allow them to perform their duties more efficiently. 

• The air hose reel on all trucks should be mounted lower or between elbow and chest height. 

• All bolt hole aligning tools should be equipped with a donut to prevent injury to hands and fingers when aligning pipes. 

Table H–6.—Surface phosphate: hydraulic pit station operator – operating hydraulic pit station 

Target task Risk factors 

Operating hydraulic pit station (N=3) 

Pit station operators are respons ble for 

operating water cannons that break 

down mined material and filter debris. 

Primary risk factors: 

• Repetitive joystick control usage 

• Excessive neck extension when viewing pump monitors 

• Contact stress – forearm and wrist 

• Awkward seated postures 

Part of the body affected: 

Discomfort surveys were used. Workers reported shoulder pain, mild to moderate, weekly. 

Ideas for improvement 

• Fully adjustable chairs would be better in the operator's compartment if the control panel would be redesigned to allow more

 adjustability. 

• Compartments should be standardized so that operators can move from one location to another and work with the same setup. 

• A new control layout design and new joysticks should be considered. 

• Monitors need to be relocated to reduce neck stress. They should be adjustable to accommodate the wide range of users. 
33 

Table H–7.—Surface phosphate: dozer operation – moving material 

Target task Risk factors 

Operating dozer (N=4) Primary risk factors: 

Dozers are used for pit preparation, • Repetitive control usage 

assisting in pit setup, and prep work for • Variable amounts of force required to operate controls 

pipelines. • Whole-body v bration and jolting/jarring 

• Frequent twisting and turning of head and neck 

• Awkward seated postures 

Part of the body affected: 

Discomfort surveys were used. All four workers reported neck and low back pain in which the pain severity was on average mild, 

but occurred weekly. 

Ideas for improvement 

• Proper standardized control handles should be used to reduce hand, arm, and shoulder stress. 

• Better mirror placement would eliminate some neck turning. 

• Additional training of mine workers to alert them of hazards of working around dozers and one-on-one training of dozer opera­

 tors can minimize the hazards of working around dozers and relieve some of the stress experienced by dozer operators. 

• Replace or redesign the dozers to meet the following design issues: suspensions that result in less jolting, jarring, and bounc­

 ing, and equipped with better cutting blades. 

Table H–8.—Surface phosphate: reagent operator – emptying reagent cars 

Target task Risk factors 

Emptying reagent cars (N=2) Primary risk factors: 

Reagent operators unload soda ash • Handling heavy tools 

from carrier cars onto a belt, which • Forceful, jerk-type exertions 

takes it to the processing plant. Their • Working with awkward upper-body postures 

job involves using heavy tools and • Working with hands above head 

working overhead. • Uneven and slippery walking surfaces 

Part of the body affected: 

Discomfort surveys were used. Wrist, hands, shoulders, neck, back, and knees were cited. Mild to moderate pain daily. 

Ideas for improvement 

• Provide operators with a hydraulic tool to turn the gate openings. 

• A vibrating mechanism inside the car or attached to the outside of the car would help to collect materials that stick to the inside

 of the cars. This mechanism would eliminate the need for pounding the cars with the hammer and rubber mallet. 

• A car puller cable system from one end of the car to the other could be developed that would move the cars from one bin door

 to the next. 

• Operators should make sure that their area is clear of debris and watch their footing. 

• Operators need to be more aware of their postures when performing this job. Aligning tools should be equipped with a donut

 to prevent injury to hands and fingers when aligning pipes. 
 

34 

APPENDIX I.—UNDERGROUND LIMESTONE MINE
 

This mine is an underground limestone operation in the 

Eastern United States with 43 employees. The site consists of 

an underground room-and-pillar stone quarry and a stone 

processing plant. At the quarry, faces and backs are scaled, 

faces are drilled and blasted, shot stone is loaded into haul 

trucks, and stone is dumped into plant hoppers or raw material 

stockpiles. At the plant, stone may be crushed and is screened 

to acquire a final product. The final product is inspected and, if 

correct, loaded into haul trucks and added to the proper 

stockpiles. 

The evaluation plan consisted of three steps. The first step 

was to select jobs for further study. A decision matrix was used 

to identify these jobs/work tasks. The matrix considered mine 

incident data, Nordic Questionnaire responses, supervisor 

interviews, and management concerns. Five work groups had 

a decision matrix score of 7 or higher out of a possible score of 

10. They were the blasting crew (9), mechanics (9), scaling 

machine operators (8), quality control technicians (7), and plant 

laborers (7). It was determined that tasks performed by the 

laborer and mechanics vary too much for effective analysis. 

The blasting crew, scaling machine operators, and the quality 

control technicians were chosen for further study. 

The second step was to select target work tasks within the 

blasting crew, mechanical scaling operations, and quality 

control technician jobs. Following work task observations and 

analysis of body part discomfort interviews, primary tasks were 

selected for each work group. They were hand scaling by the 

blasting crew, handling ANFO and dynamite by the blasting 

crew, scaling faces and backs by the scaling machine operators, 

and gathering samples by the quality control technicians. 

The final step was to use video task analysis and brainstorming sessions with mine workers to characterize ergonomic 

risk factors and develop general risk reduction ideas. A brief 

overview of the baseline data, a copy of the decision matrix, risk 

factors identified, and general ideas for task improvement are 

presented below. 

INCIDENT DATA 

The mine provided nearly 31⁄2 years of incident data from 

January 1, 1997, to May 31, 2000. Seventeen records were obtained. These incidents involved near-misses, medical treatment, 

and lost work time. Incident data were reviewed and summarized 

by the evaluation team. An incident ratio was calculated for each 

work group. Table I–1 shows the number of employees and an 

incident ratio for each work group. The incident ratio gives a 

relative estimate of the incident risk for each work group. The 

three groups with the highest incident ratio are the blasting crew, 

crusher operators, and mechanics. Table I–2 summarizes the 

17 incidents by work group and incident type. Each incident narrative was reviewed and classified as one of five types: 

(1) jarred/bounced, (2) slip/fall, (3) caught between/struck by, 

(4) overexertion, or (5) other. The most common incident type, 

which accounted for more than half of the incidents (10 of 17, or 

59%), was "caught between/struck by." 

Table I–1.—Underground limestone: number of incidents and
 

employees by work area, job title, and incident rate,

January 1997–May 2000
 

Work area and

 job title Incidents Employees Average annualincident rate1 

Mine and plant:

 Supervisors ......... 0 3 0

 Haul truck operators . . 3 10 0.09 

Mine:

 Driller operators ...... 1 5 0.06

 Blasting crew . . . . . . . . 3 4 0.21

 High-lift/loader

 operators ......... 1 4 0.07

 Mechanics .......... 3 4 0.21

 Scaling machine

 operators ......... 1 3 0.10

 Water truck operator . . 0 1 0 

Plant:

 Quality control

 technician . . . . . . . . . 0 1 0

 Laborer ............ 0 1 0

 Welder . . . . . . . . . . . . . 0 1 0

 High-lift/loader

 operators ......... 0 3 0

 Crusher operators .... 2 3 0.19

 Total . . . . . . . . . . . . 17 43 0.11 1

Average annual incident rate = reported incidents divided by estimated

number of employees divided by 3 years. 

NORDIC QUESTIONNAIRE 

Questionnaire responses were evaluated by counting the 

number of body parts reported and the number of reports of 

discomfort in similar body parts for each work group. Table I–3 

shows the number of body parts with discomfort reported by each 

work group. Forty of forty-three workers responded to the 

questionnaire. The site-wide average of reported body parts with 

discomfort was about three per person. The average number of 

body parts with discomfort reported by mechanics, the quality 

control technician, the water truck operator, and supervisors was 

somewhat higher. Table I–4 shows reported body part discomfort 

that was rated as "above average" or "below average" by work 

group. To be considered “above average,” response percentages 

had to be at least 50% higher than the overall percentage for 

reported discomfort over the past year or the past week. 

Similarly, “below average” response percentages had to be at least 

50% lower than the overall percentages for reported discomfort 

over the past year or the past week. If a body part does not appear 

in the table, it was considered to have an “average” rating of 

reported discomfort. Work groups that reported higher than 

average body part discomfort were mechanics, scaling machine 

operators, the water truck driver, the quality control technician, 

and supervisors. 

SUPERVISOR INTERVIEWS 

Eight work groups were identified as having physically demanding tasks by three site supervisors. Comparative ratings 

were assigned by the evaluation team and were based on consensus discussions. A rating can be "low," "medium," or "high." The 

blasting crew, mechanics, and the plant laborer were rated as 

having "high" physical demands. Table I–5 summarizes supervisor interview comments for these three work groups. 
35

Table I–2.—Underground limestone: incidents by work group and incident type, 

January 1997–May 2000 

Work group 

Incident type 

Jarred/ Total

bounced 

Caught

Slip/fall between/ 

struck by 

Overexertion Other

Supervisors ................... 0 

Haul truck operators ............. 2 1 3 

Driller operators ................ 1 1 

Blasting crew . . . . . . . . . . . . . . . . . . 1 2 3 

Mine high-lift/loader operators ..... 1 1 

Mechanics .................... 2 1 3 

Scaling machine operators ........ 1 1 

Water truck operator ............. 0 

Quality control technician . . . . . . . . . 0 

Plant laborer ................... 0 

Welder . . . . . . . . . . . . . . . . . . . . . . . 0 

Plant high-lift/loader operators ..... 0 

Crusher operators ............... 1 1 2 

Unknown . . . . . . . . . . . . . . . . . . . . . . 1 2 3

 Total . . . . . . . . . . . . . . . . . . . . . . . 4 1 10 1 1 17 

Table I–3.—Underground limestone: number of reported body parts with discomfort by work group 

Work group No. of 

respondents Mine 

No. of body parts 

Plant Supervisor Total Average 

Supervisors ...................... 

Haul truck operators ................ 

3 

9 20 2 

15 15 

22 

5.0 

2.4 

Driller operators ................... 

Blasting crew . . . . . . . . . . . . . . . . . . . . . 

5 

4 

8 

8 

8 

8 

1.6 

2.0 

Mine high-lift/loader operators ........ 

Mechanics ....................... 

3 

4 

8 

20 

6 

20 

2.0 

5.0 

Scaling machine operators ........... 

Water truck operator ................ 

2 

1 

9 

12 

7 

12 

3.5 

12 

Quality control technician . . . . . . . . . . . . 

Plant laborer ...................... 

1 

1 

11 

2 

11 

2 

11 

2.0 

Welder . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2 2 2.0 

Plant high-lift/loader operators ........ 3 1 1 0.3 

Crusher operators .................. 

 Total . . . . . . . . . . . . . . . . . . . . . . . . . . 

3 

40 85 

7 

25 15 

7 

125 

2.3

3.1 

Table I–4.—Underground limestone: Nordic Questionnaire responses by work group 

Work group Above average ratings Below average ratings 

Supervisors .................. Neck, wrists/hands, upper back, knees . . . E bows, hips/thighs. 

Haul truck operators ............ 

Driller operators ............... 

None . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

None . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Neck. 

E bows, wrists/hands, hips/thighs, ankles/feet. 

Blasting crew . . . . . . . . . . . . . . . . . 

Mine high-lift/loader operators .... 

E bows . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

E bows . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Neck, upper back, hips/thighs, ankles/feet. 

Wrists/hands, hips/thighs, knees, ankles/feet. 

Mechanics ................... 

Scaling machine operators ....... 

Neck, shoulders, hips/thighs, knees ...... 

Neck, wrists/hands, upper back, knees . . . 

Ankles/feet. 

Shoulders, elbows, hips/thighs. 

Water truck operator ............ 

Quality control technician . . . . . . . . 

All body parts ....................... 

All body parts ....................... 

None. 

None. 

Plant laborer .................. 

Welder . . . . . . . . . . . . . . . . . . . . . . 

Lower back and wrists/hands ........... 

Lower back and knees ................ 

Neck, shoulders, e bows, upper back, hips/

 thighs, knees, ankles/feet. 

Neck, shoulders, e bows, wrists/hands, upper

 back, hips/thighs, ankles/feet. 

Plant high-lift/loader operators .... 

Crusher operators .............. 

None . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Lower back . . . . . . . . . . . . . . . . . . . . . . . . . 

All body parts except lower back. 

Shoulders, elbows, wrists/hands, hips/thighs. 
 

 

 

36 

DECISION MATRIX 

Results of the decision matrix are shown in table I-6. Five 

work groups received a score of 7 or higher: the blasting crew 

(9), mechanics (9), scaling machine operators (8), quality 

control technician (7), and plant laborer (7). It was determined 

that tasks performed by the laborer and mechanics vary a lot 

from day to day. This meant that selecting and studying specific 

tasks would be difficult. For this reason, the blasting crew, 

scaling machine operators, and the quality control technician 

were chosen as the target work groups. 

BODY PART DISCOMFORT INTERVIEWS 

Four blasting crew members, three scaling machine operators, 

and one quality control technician were interviewed. The quality 

control technician had felt pain in his back and knees every day. 

Pain in his upper and midback had been mild, but the low back 

and knee pain had been moderate. He noted that recently he had 

felt unbearable pain in his upper legs and continued to have pain 

in this area. All members of the blasting crew interviewed had 

felt pain in their shoulders. Two members had felt pain in their 

elbows. The average pain severity in these two areas was mild to 

moderate, but the pain occurred at least a couple of times per 

week. In addition, the member of the blasting crew who fills 

ground holes reported daily severe or unbearable pain in his knees 

and ankles. All scaling machine operators had felt pain in their 

neck. Two operators had felt pain in all areas of their back and in 

their knees. Neck pain is felt nearly every week but is considered 

mild. Back pain is felt at least a couple of times per week (upper 

back pain is felt every day). 

TASK-SPECIFIC RESULTS 

Tables I–7 to I–10 summarize information gathered for the 

specific tasks studied at the underground limestone mine. Ideas 

to reduce risk factors were developed based on brainstorming 

sessions with those who had a stake in the task, i.e., those who 

performed the task, supervisors, safety representatives, and 

engineering and maintenance staff. NIOSH personnel facilitated 

the brainstorming sessions. It should be noted that all ideas generated during brainstorming are listed. The ideas for improvement are not listed in any particular order with regard to likelihood of successfully reducing risk factor exposure or ease of 

implementation. These ideas are unique to this mine site and the 

tasks observed and should not be generalized to all mine sites. 

Table I–5.—Underground limestone: physically demanding jobs identified by supervisors 

Work groups with 

physically demanding tasks Key comments Rating 

Blasting crew . . . . . . . . . . . . Hand scaling is physically demanding. Workers use a scaling bar to pull loose rock from 

faces and backs. A high degree of pushing and pulling force must be applied to the pry 

bar. They lift and carry 50- to 55- b bags and boxes of dynamite and ANFO. They clean 

out bottom holes at a drilled face with a handheld hoe while working on a rocky bottom. 

High. 

Mechanics .............. Workers handle heavy crib blocks, 250 lb each. They must lift, carry, and position the 

cr bbing as safety blocks before working on equipment. They do a lot of bending, lifting, 

and crawling around inside machines. This results in awkward postures and work in 

confined spaces. 

High. 

Plant laborer ............. 75% production, 25% maintenance. The most physically demanding tasks are normal 

production cleanup duties. The worker is at risk of trips and falls on catwa ks, where 

there are lots of uneven, muddy, wet, or icy surfaces. He repeatedly uses a grease gun. 

During maintenance he changes screens and bearings, cuts and welds, and does a lot of 

lifting and carrying. 

High. 

Table I–6.—Underground limestone: decision matrix for selecting tasks 

Work group No. of 

employees 

Incident 

data 

Nordic 

Questionnaire 

Supervisor 

interviews 

Management 

concern 

Final

score 

Supervisors .................. 3 Low High Low 5 

Haul truck operators ............ 10 Medium Medium Low 5 

Driller operators ............... 5 Medium Low Low 4 

Blasting crew . . . . . . . . . . . . . . . . . 4 High Medium High Yes 9 

Mine high-lift/loader operators .... 4 Medium Medium Medium 6 

Mechanics ................... 4 High High High 9 

Scaling machine operators ....... 3 Medium High Medium Yes 8 

Water truck operator ............ 1 Low High Low 5 

Quality control technician . . . . . . . . 1 Low High Medium Yes 7 

Plant laborer .................. 1 Low Medium High Yes 7 

Welder . . . . . . . . . . . . . . . . . . . . . . 1 Low Medium Low 4 

Plant high-lift/loader operators .... 3 Low Low Low 3 

Crusher operators .............. 3 High Medium Low 6 
38 

Table I–7.—Underground limestone: quality control technician – gathering and testing samples 

Target task Risk factors 

Gathering samples (N=1) Primary risk factors: 

A sample is shoveled into a bucket at • Forceful exertions with shoulders and back when shoveling 

a stockpile and driven back to the lab. • Concentrated pressure points to hand from a power grip on the bucket handle 

The sample is then carried down • Lifting and carrying heavy loads, 40- to 70-lb buckets 

13 steps to the lab. • Asymmetric load handling when carrying one bucket 

• Ascending and descending steps while carrying loads 

• Ascending and descending steps with hand(s) occupied 

Testing sample (N=1) Primary risk factors: 

A sample is split, weighed, and dried, • Twisting, turning, and bending while handling sample pans 

shaken for 10 min, and weighed again. • Lifting loads above shoulders to dump 

When testing is done, the sample is • Pulling trays and lifting loads from below knuckle height 

dumped back into the bucket. • Dust in the lab when analyzing a sample 

Part of the body affected: 

Discomfort surveys were used. One worker reported pain. Average to moderate pain: upper, mid, and lower back; knees; neck; 

shoulders; and upper legs. 

Ideas for improvement 

• Use a shovel/spade that will push more easily into the sampling pile. 

• Park the truck as close as possible to the sampling pile to reduce carrying distances and worker exposure to equipment traffic. 

• Attach a platform to the rear of the truck to place samples in instead of into the truck bed. 

• Use soft rubber padding around the bucket handle to reduce concentrated pressure to hand. 

• Use a bucket size that holds a maximum of 40 lb without overfilling. 

• When collecting a heavier sample, shovel into two buckets. When carrying two buckets, keep the weight balanced and a maximum of 35 lb per bucket. 

• If possible, place the lab at ground level. This would eliminate the need to go up and down stairs and would significantly

 reduce materials handling. 

• If a ground level lab is not poss ble, develop an electric winch or other conveyance system that would transport samples

 down to and up out of the lab. 

• A better lab layout would improve process flow and reduce handling and twisting. 

• When dumping or transferring samples, try to keep the pan at hip height and do not raise the elbow above shoulder. 

• Antifatigue mats could help reduce aches and pain to lower extremities and lower backs. 

Table I–8.—Underground limestone: blasting crew – handling ANFO and dynamite 

Target task Risk factors 

Handling ANFO and dynamite (N=4) 

The crew unloads bags of ANFO from a 

storage trailer and boxes of dynamite 

from a secure storage shed into the 

back of a truck. ANFO is then loaded 

into the hopper of the blaster's truck. 

Primary risk factors: 

• Bending over, twisting, and reaching to lift ANFO in 50-lb bags and dynamite in

 55- b boxes 

• Carrying awkward and heavy loads 

• Loading ANFO into the hopper requires twisting and lifting with the elbow above

 shoulder 

Part of the body affected: 

Discomfort surveys were used. Four workers reported pain. Average to moderate pain: shoulders, mid and low back. 

Ideas for improvement 

• Increase worker awareness of proper lifting and carrying techniques. This should include a problem-solving component and

 would include ergonomic principles that relate to blasting crew tasks performed at the site. 

• Work with suppliers to provide smaller ANFO and dynamite packaging, no more than 40 lb. 

• Modify the layout of ANFO and dynamite storage to reduce bending, twisting, and lifting distances. Consider spring-loaded

 pallets for ANFO bags. 

• A better, long-term solution would be to eliminate manual loading and unloading of ANFO. Store bu k material in a silo so that

 the ANFO can be directly loaded into the truck hopper. 
39 

Table I–9.—Underground limestone: blasting crew – hand scaling and clearing bottom holes 

Target task Risk factors 

Hand scaling (N=4) Primary risk factors: 

Before loading blast holes, two crew 

members are raised in a basket to 

knock and pry loose stone from the 

back and face using a pry bar. 

• Forceful exertions with arms, shoulders, and back; the 8-ft pry bar creates a high

 force moment arm 

• Impact forces to hands, elbows, and shoulders when hammering with pry bar 

• Extended forward reaches when cleaning face 

• Working with arms above shoulder height 

• Working below the feet to remove material 

• Neck flexion when working with high and low targets 

• Wrist flexion/extension when prying material 

• Environment can be noisy, dark, smoky, foggy, and humid 

Clearing bottom holes (N=4) Primary risk factors: 

After hand scaling, the ground man • Working on rocky, uneven ground, causing twisting and turning of ankles and knees 

clears loose rock from the bottom • Forceful exertions with hands, arms, and shoulders 

holes using a hand shovel. • Working in kneeling or bent-over postures 

Part of the body affected: 

Discomfort surveys were used. All four workers reported pain in the shoulders. Mild to moderate pain in the elbows. Clearing 

bottom holes often results in pain to the knees and ankles. 

Ideas for improvement 

• Try different types of scaling bars to reduce effort required. Ideas for improving the scaling bar: use an s-shaped bar that

 would require less movement when prying; use as much fiberglass as possible with a thin metal center; try to counterbalance

 the bar. 

• Look for ways to eliminate hand scaling using some type of fail-safe extendable canopy. 

• The scaling basket should be repositioned more frequently to reduce reaches and poor postures. 

• Try to level and clean the floor before filling ground holes. A small scoop could be used after the hand scaling is done. 

• Keep the ground holes at least 3 to 4 in off the floor. 

• The ground man should use appropriate kneepads. 

Table I–10.—Underground limestone: scaling machine operator – mechanical scaling of face and back 

Target task Risk factors 

Scaling face and back (N=3) Primary risk factors: 

The operator works two hydraulic joy­ • Constant bouncing and jarring while scaling 

stick controls to scrape the tooth of the • The feet bounce on the floor of the compartment and against control stands 

machine along the face or back, looking • The operator uses repetitive hand and wrist movements to operate controls 

for loose stone. Once loose stone is • Pushing and pulling on controls require frequent arm and shoulder exertions 

found, he pokes and scrapes with the • The neck is flexed back when scaling the back 

tooth to knock the stone free. • When scaling the back from the bench, you must lean forward to look up; the neck

 is not well supported 

Part of the body affected: 

Discomfort surveys were used. Three workers reported pain. Average to moderate pain: neck, upper and mid back, knees, and 

forearms. 

Ideas for improvement 

• The ability of the seat to absorb shock is key. The newer seat that absorbs shock the best should be used in both machines

 unless a better seat is found. 

• There may be a better seat design. Consider the air seats used in some haulage trucks. 

• Any seat will wear out quickly in this situation. Evaluating and replacing the shock absorption system or the entire seat in a

 timely manner is important. 

• Improve the shock-absorbing characteristics of the operator compartment. One example would be to use shock-absorbing

 floor material. A long-term approach would be to work with an original equipment manufacturer (OEM) to build a machine

 with an isolated or free-floating compartment. 

• The seat should have a soft, adjustable support for the neck and head. 

• Consider testing alternate joystick controls to find one that would reduce hand and arm activity. 

• Regular breaks to move about and loosen up should be allowed. Rotating work crews using a split-shift approach would be the

 best way to reduce daily exposures to whole-body vibration. 

• The best long-term approach is to work with an OEM to develop a remote-controlled scaling machine. For this to work, you

 must consider the type of operator feedback needed and the type of controller that will work best and provide adequate

 lighting.