An Analysis of Injuries to Haul Truck Operators in the U.S. Mining Industry 

Brenda R. Santos, William L. Porter, Alan G. Mayton
 

National Institute for Occupational Safety and Health, Office of Mine Safety & Health Research, 

626 Cochrans Mill Road, P.O. Box 18070, Pittsburgh, PA 15236 

Because haul trucks are used extensively in mining, the operators of these trucks are exposed to various 

risks and hazards inherent to this occupation. The objective of this work was to profile injuries sustained 

during haul truck operations, to identify priorities for further investigation, and to determine potential 

injury prevention strategies. Data from the Mine Safety and Health Administration (MSHA) annual 

administrative database were sorted and reviewed to select records identifying a subset of injuries sustained 

during haul truck operations. Records covering a 5-year period (2004–2008) involving haul trucks were 

reviewed. The majority of the injury records were for injuries classified as “struck against moving object” 

(STRUCK) (N=613) and “slip or fall of person from an elevation or on the same level” (SLIPFALL) 

(N=359). Each injury narrative was read to determine the activity being performed during the injury (such 

as ingress, egress, driving, maintenance), the incident results (such as operator impact and truck impact), 

contributing factors to the event, and environmental factors. The nature of the injury, body parts affected, 

as well as lost work days were also quantified. The average lost work days for STRUCK and SLIPFALL 

injuries was 60 and 62, respectively. The majority of the total incidents resulted in sprain and strain 

injuries; the back was the most frequently injured body part injured. For STRUCK injuries, the majority of 

activities being performed at the time of the injuries involved driving (63%). More than one-third of the 

total incidents resulted in vertical jarring of the haul truck (36%), and the majority of the total incidents 

caused jolting and jarring to the operator (75%). For SLIPFALL injuries, the majority of incidents occurred 

during egress from the vehicle (46%), and of the total incidents, 32% resulted in the worker falling. Almost 

one-third of the total incidents were due to the operator’s foot slipping (32%). Further investigation should 

focus on the factors contributing to haul truck operators being struck against a moving object and those 

related to operators slipping and falling. 

INTRODUCTION 

The operation of earth-moving equipment often contributes to 

prolonged and high magnitude vibration exposure. Haul 

trucks are used extensively in mining, and the operation of 

these trucks is characterized by repetitive tasks such as driving 

while exposed to whole-body vibration (WBV). Exposure to 

WBV and the postural requirements of the job have been 

identified as important risk factors in the development of 

musculoskeletal disorders of the spine among workers 

(Kittusamy & Buchholz, 2004; Kittusamy, 2002; Bovenzi & 

Zadini, 1992; Johanning, 1991; Bongers, Boshuizen, & 

Hulshof, 1988; Bongers, Hulshof, Dijkstra, & Groenhout, 

1990). 

Haul truck operations are also characterized by non-repetitive 

tasks such as exiting the cab to change a filter or clean a 

window. During some maintenance activities that operators 

perform (as in the latter example), there is a risk of the worker 

falling off of equipment. According to a National Institute for 

Occupational Safety and Health (NIOSH) analysis of Mine 

Safety and Health Administration (MSHA) nonfatal, lost-time 

injuries between 2002 and 2006, slip and fall of a person 

accounted for 25% of mining injuries (NIOSH, 2008). In the 

Spanish mining sector, just over 17% of serious or fatal 

accidents were caused by “people falling down at different 

levels” (Sanmiquel, Freijo, Edo & Rossell, 2010). Some of 

these falls from equipment occur while entering or exiting 

equipment via ladders or stair systems. However, factors 

contributing to these falls are largely unknown. 

Once an incident (whether it be an accident, injury, or illness) 

has occurred, the information that is documented regarding 

the incident is a valuable source. This information leads to 

better understanding of the circumstances or causes of the 

incident, thereby allowing the use of methods (i.e., 

engineering controls, administrative controls, or personal 

protective equipment) to protect from and prevent further 

incidents that are similar in nature. The purpose of this work 

was to profile and describe injuries sustained during haul 

truck operations and to identify priorities for further field 

investigation and any potential injury prevention strategies. 

METHODS 

MSHA provides an annual administrative database containing 

all reportable injuries, illnesses, and fatalities sustained in 

mining. MSHA regulations (30 CFR 50.20) require mine 

operators and contractors to file a Mine Accident, Injury and 

Illness Report (MSHA Form 7000-1) for each accident, 

occupational injury, or occupational illness that occurs at a 

mine site. This comprehensive data set was sorted and 

reviewed to select records that identify the injuries sustained 

during haul truck operations or by haul truck operators during 

tasks related to maintenance. 

Injury Record Selection 

Records were chosen from the MSHA injury, illness, and 

fatality database if the incident: 
 

1.	 occurred between January 1, 2004 and December 31, 

2008 

2.	 involved the operation of a haulage truck on mine 

property (both surface mines, including coal preparation 

and minerals processing plants, and underground mines) 

by mining company employees or contractors to perform 

a common production task 

3.	 resulted in either 

a.	 a fatality 

b.	 permanent, partial, or total disability 

c.	 days away from work only 

d.	 days away from work and restricted activity 

e.	 days of restricted activity only 

Injury records from the MSHA database were selected based 

on the above criteria. This strategy yielded a data set of 1,382 

records. Cross tabulations of accident type by accident 

injury/illness classification for all records were examined. 

Two subgroups of injury classification accounted for 70% of 

the data set and were identified as needing further analysis. 

All other subgroups accounted for less than 12% of the data 

set and were not further examined. The injury subgroups that 

were not included in the final analysis included: 1) 

overexertion, 2) handling materials, 3) powered haulage, and 

4) machinery. The records retained for the final analysis were 

those where the: 1) accident type was classified as “struck 

against moving object” (STRUCK) (N=613); and 2) accident 

injury illness were classified as “slip or fall of person (from an 

elevation or on the same level)” (SLIPFALL) (N=359). 

Coding of the Records 

In order to have a better understanding of the injuries 

sustained, all of the injury narratives1

1

 Narratives are short summaries prepared by an individual at 

the mine site completing the MSHA Form 7000-1. 

were manually coded 

and reviewed individually by two of the researchers (BRS and 

WLP). A classification system was used to code information 

contained in the narrative. The development of the 

classification system was adapted and modified from 

Wiehagen, Mayton, Jaspal and Turin (2001) and Moore, 

Porter and Dempsey (2009). A list of variables, and various 

descriptor categories associated with each variable, are 

described in the following two paragraphs. 

Struck against moving object. A total of five 

variables were used: 1) activity, 2) truck impact, 3) operator 

impact, 4) contributing factors to the event, and 5) 

contributing events to the severity. Activity was defined to 

code the task being performed by the haul truck operator at 

the time of injury, such as driving, loading or unloading2

2

 The driver was not performing the actual loading and 

unloading. The driver was in the haul truck as these tasks 

were performed by others. 

of 

the haul truck, or performing maintenance. The truck impact 

describes what happened to the haul truck, such as 

fallover/rollover/fall into void, struck by an object, struck an 

object, or vertical jarring. The operator impact describes what 

happened to the operator, such as having been jolted and 

jarred, struck by an object, or having sustained a 

musculoskeletal injury (MSI). Contributing factors to the 

event offered information that may have contributed to the 

occurrence such as an edge or slope failure, hidden void (e.g., 

potholes), or equipment failure. Contributing events to the 

severity were used for cases where information was reported 

about factors that may have either enhanced or decreased the 

severity of the injury, such as whether the operator was 

wearing a seatbelt or not, or if the operator was thrown out or 

jumped out of the cab. 

 

Slip or fall of a person. Four variables were used: 1) 

activity, 2) operator impact, 3) contributing factors to the 

event, 4) environmental factors. Activities included ingress, 

egress, performing maintenance, or regular driving operations. 

The operator impact described what happened to the operator, 

such as fell, slipped (with and without falling), or sustained an 

MSI. Contributing factors to the event offered information 

that may have contributed to the occurrence such as 

equipment failure, foot got caught or slipped, lost balance, lost 

hand grip, or missed a step. Environmental factors reported 

poor environmental conditions that may have contributed to 

the event such as wet, icy, or muddy conditions. 

Once the narratives were read and analyzed by the two 

reviewers (BRS and WLP), the narratives with discordant 

coding were determined. Subsequently, all discrepancies were 

resolved through discussions between the two researchers and 

a third team member (AGM). 

Statistical Analysis 

Descriptive statistics were calculated for the MSHA database 

variables and the coded variables discussed above. 

RESULTS 

The majority of the workers injured were males STRUCK: 

males [n=546, 89%], females [N=67, 11%]; SLIPFALL: 

males [N=338, 94%], females [n=21, 6%]. Table 1 

summarizes the demographic information of the injured haul 

truck operators analyzed for this analysis. For simplicity, the 

results for both genders have been grouped together. 

Table 1: Demographic information of injured haul truck operators. 

Mean (Standard Deviation) 

STRUCK SLIPFALL 

(N=613) (N=359) 

Age (years) 40 (13) 41 (14) 

Lost work days 60 (75) 62 (78) 

Current job experience (weeks) 567 (967) 564 (821) 

Total experience this mine (weeks) 493 (1101) 404 (718) 

Total mining experience (weeks) 602 (937) 766 (1016) 
Struck Against Moving Object 

More than one-half of the injuries sustained were sprains and 

strains (Table 2). Other injuries (not listed in Table 2) were 

also reported (e.g., concussion, cuts, lacerations, puncture, 

joint inflammation); however, each of these only accounted 

for less than 2 percent of the total injuries. 

Table 2: The nature of “struck against moving object” injuries 

(number and percentage) (N=613) 

N %

Sprain/strain 340 56

Unclassified, not determined 65 11 

Contusion, bruise 63 10 

Fracture, chip 59 10 

Multiple injuries 37 6 

Cut, laceration, puncture 30 5 

The most frequently injured body part was the back (N=221, 

36%), followed by multiple body parts (N=137, 22%), the 

neck (N=82, 13%), and shoulder(s) (N=43, 7%). Injuries to 

other body parts were also reported; however, each of these 

accounted for less than 4 percent of the total injuries. 

Based on the coding of the narratives, almost two-thirds of the 

injuries occurred while the operator was driving (either in the 

forward or backward direction), followed by loading then 

unloading (Table 3). For 5 percent of the narratives, the 

activity was unknown (N=28) and for less than 5 percent of 

the narratives (N=14), other activities were being performed 

(not shown in Table 3). An example of a narrative where 

“other” was coded for the activity is: 

“When loader operator picked up the hauler to set it off the 

rock [which rolled under the hauler], the bucket slipped, 

shaking the hauler and employee.” 

Table 3: Activity being performed while injury was sustained 

(N=613) 

N %

Driving (forward) 229 37 

Loading 137 22

Driving (unknown direction) 97 16 

Driving (backward/reversing) 60 10 

Unloading 48 8

Slightly more than one-third of the incidents causing injury 

resulted in vertical jarring of the haul truck (N=218, 36%) 

occurring mainly during loading and driving (forward) 

activities. Twenty-eight percent resulted in the haul truck 

falling/rolling over or falling in a void (N=171), with the 

majority occurring while driving in the backward direction. 

Incidents also resulted in collisions with other vehicles (N=57, 

9%). For a small percentage of the total incidents, there was 

no apparent impact to the haul truck (N=44, 7%) or it was 

unknown whether or not there was any impact to the haul 

truck (N=36, 6%). 

In terms of the impact to the operator, three-quarters of the 

total incidents resulted in jolting and jarring of the operator 

(N=461). Of these (jolting and jarring injuries), 12% resulted 

in the operator striking against an object inside the cab 

(N=74). Almost one-fifth of the total incidents resulted in an 

MSI (N=115) and the operator impact was unknown for 6 

percent of the total incidents (N=35). 

Forty-three percent (N=264) of the narratives did not offer any 

information regarding the contributing factors to the event. 

Just over one-quarter of the incidents had the contributing 

factors classified as “other” (N=164). An example would be: 

“While returning to the pit area employee fell asleep. 

Equipment crossed over a window, causing the operator to be 

knocked around ... causing injury ...” 

Other contributing factors to the event that were noted were 

equipment failure (N=80, 13%) and hidden voids (e.g., 

potholes) (N=57, 9%). 

The contributing factors to the severity of the event was 

largely coded unknown (N=574, 94%) and it was indicated for 

only approximately 5 percent of the total number of incidents 

whether or not the operator was wearing a seatbelt (N=32). 

Slip or Fall of Person (from an elevation or on the same 

level) 

As with the “struck against moving object” injuries, the most 

common “slip or fall of a person” nature of injury was 

sprains/strains (Table 4). Other injuries (not listed in Table 4) 

each accounted for less than 5 percent of the total injuries. 

Table 4: The nature of “slip or fall of a person” injuries (number and 

percentage) (N=359) 

N %

Sprain/strain 151 42

Fracture, chip 87 24 

Unclassified, not determined 43 12 

Contusion, bruise 42 12 

Multiple injuries 17 5 

The back was the most frequently injured body part (N=64, 

18%), followed by the knee (N =49, 14%), multiple body 

parts (N =41, 11%), ankle (N =39, 11%), shoulder(s) (N =34, 

10%), and chest (N =19, 5%). 

The coding of the narratives revealed that almost one-half of 

the incidents occurred during egress from the vehicle and 

almost one-quarter occurred during ingress (Table 5). Sixteen 

percent (N=58) of these injuries occurred during maintenance 

activities. A small percentage was classified as either being 

“other” or “unknown.” An example of a narrative where 

“other” was coded for the activity is: 

“Employee did not have hold of hand hold that was provided 

to enable him to have 3 point contact.” 
 

Table 5: Activity being performed while injury was sustained 

(N=359) 

N %

Egress 165 46

Ingress 81 23

Maintenance 58 16

Other 27 8

Unknown 20 6

Approximately one-third of the total incidents resulted in the 

operator falling (either forward or backward) (N=115, 32%) 

and approximately one-quarter resulted in slipping and falling 

(N=94, 26%). The incidents also resulted in the operator 

sustaining an MSI (N=90, 25%) and slipping (but without 

falling) (N=50, 14%). 

The contributing factors to the event are summarized in Table 

6. The majority of the contributing factors were due to the foot 

slipping, and a large proportion of factors were unknown. 

Other contributing factors not listed in the aforementioned 

table each only accounted for less than 3 percent of the total 

incidents. 

Table 6: Contributing factors leading to an event (N=359). 

N %

Foot slipped 116 32 

Unknown 86 24

Other 30 8

Lost footing/slipped 27 8 

Equipment failure 24 7 

Missed step 22 6 

Lost hand grip/hand slipped 20 6 

Environmental factors were noted for 11% of all incidents 

(N=40). Wet, icy, and muddy conditions were each only 

indicated for less than four percent of the incidents. 

DISCUSSION 

Injuries sustained during haul truck operations were analyzed 

in order to identify priorities for further investigation and 

potential injury prevention strategies. Injury records with 

accident type classified as “struck against moving object” and 

accident injury illness classified as “slip or fall of person 

(from an elevation or on the same level)” accounted for a 

large proportion (70%) of the total injuries recorded between 

2004 and 2008. 

For the “struck against moving object” injuries, the majority 

occurred while the operator was driving the haul truck and the 

majority of operators sustained back injuries. Further 

investigation showed the impact to the haul truck was 

primarily vertical jarring while driving in the forward 

direction, thus causing jolting and jarring to the operator. The 

primary factor contributing to these vertical jarring events 

were hidden voids (e.g., potholes) that were noted on the haul 

roads. Driving in the backward direction, however, resulted in 

different outcomes. A large number of injuries resulted in haul 

truck rollovers, fallovers, or falling into hidden voids. The 

contributing factors to these types of incidents were largely 

unknown. However, equipment failure (e.g., axle housing 

separating, tire rod breaking) was identified as a contributing 

factor. Another factor contributing to a large proportion (38%) 

of these types of incidents (i.e., driving backwards resulting in 

the haul truck rolling over) was the operator having fallen 

asleep. Given the long work duties and possible night shifts, 

driver fatigue and sleepiness are possible. In 1995, a major 

truck and bus safety summit meeting identified driver fatigue 

as the primary truck safety issue (Truck & Bus Safety 

Summit, 1995). Methods to better identify these components 

in haul truck operators could help prevent such incidents. 

More than 60% of the total injuries related to “slip or fall of 

person (from an elevation or on the same level)” occurred 

during egress and ingress, with the majority during egress. 

This concurs with previous work that has shown a large 

proportion of injuries having occurred during ingress or egress 

of large mining vehicles (Moore, Porter & Dempsey, 2009; 

Randolph, 1997). The major contributing factor to these 

incidences is foot slipping. Therefore, reasons why these 

incidences occur, whether it is due to the operator’s decreased 

sense of awareness of surroundings or environmental 

conditions (although our analyses did not demonstrate this) 

are topics for further investigation. 

In 2001, Turin, Wiehagen, Jaspal, & Mayton reported similar 

findings in an examination of haul truck injuries relative to 

dump site safety between 1988 and 1997. Three primary haul 

truck activities were selected: stationary dumping, backing up, 

and moving forward. Greater than 90% of the serious injuries 

occurred during stationary dumping and backing up. Most 

frequently, injuries resulted from the haul truck falling over an 

edge while backing up, the operator being bounced and/or 

jarred while dumping, and the haul truck rolling over while 

dumping. Moreover, injuries were evaluated by effects on the 

operator, and by haul truck activity. For effects on the 

operator, “struck against object” accounted for more than onehalf of all serious injuries, including seven fatalities. For haul 

truck activity, the researchers reported that for just under onequarter of the total injuries, the result was the operator 

“bouncing or jarring.” The researchers highlighted safe work 

practices relevant to haul trucks backing up and stationary 

dumping. These practices included devices such as cameras or 

proximity detection to assist drivers at dump points during 

backing up, or having the haul truck dump short with dozer 

assistance to push the pile over the edge. Other best practices 

include ensuring that a thorough preoperation inspection 

becomes a habit; mud, grease, or ice is cleaned off boots and 

ladders; and seatbelts are used. In summary, it is important to 

highlight these best practices and encourage mines to develop 

and maintain a comprehensive risk reduction strategy, which 

is key to enhancing haul truck dump site safety and efficiency. 

This descriptive analysis of MSHA injury data related to 

injuries sustained during haul truck operations found that the 

majority of injuries were classified as resulting from “struck 

against moving object” or “slip or fall of person from an 
elevation or on the same level.” After reading through the 

narratives, we were able to identify contributing factors to the 

events, the impact on the truck and operator, and 

environmental factors leading to the incidents. These all lead 

to better understanding of the circumstances of the injuries, to 

encourage the development of controls (e.g., engineering, 

administration) to reduce the frequency and severity of such 

injuries, and to prioritize areas for further investigation. 

However, methods of reporting such injuries in the MSHA 

database could be incomplete, and they also vary from one 

person to another. Therefore, an in-depth task analysis and 

additional field investigations should be carried out to fully 

understand injuries related to haul truck operations. 

DISCLAIMER 

The findings and conclusions in this paper are those of the 

authors and do not necessarily represent the views of the 

National Institute for Occupational Safety and Health. 

REFERENCES 

Bongers P.M., Boshuizen H.C., Hulshof C.T.J. & 

Koemeester A.P. (1988). Back disorders in crane 

operators exposed to whole-body vibration. 

International Archives of Occupational and 

Environmental Health 60(2), 129–137. 

Bongers P.M., Hulshof C.T.J., Dijkstra L., Boshuizen H.C., 

Groenhout H.J. & Valken E. (1990). Back pain and 

exposure to whole-body vibration in helicopter 

pilots. Ergonomics, 33(8), 1007–1026. 

Bovenzi M. & Zadini A. (1992). Self-reported low back 

symptoms in urban bus drivers exposed to wholebody vibration. Spine, 17(9), 1048–1059. 

Johanning E. (1991). Back disorders and health problems 

among subway train operators exposed to wholebody vibration. Scandinavian Journal of Work 

Environment and Health, 17(6), 414–419. 

Kittusamy N. (2002). Ergonomic risk factors: A study of 

heavy earthmoving machinery operators. 

Professional Safety—Journal of the American Society 

of Safety Engineers, October, 38-45. 

Kittusamy N.K. & Buchholz B. (2004). Whole-body vibration 

and postural stress among operators of construction 

equipment: A literature review. Journal of Safety 

Research, 35, 255–261. 

Mine Safety and Health Administration (1992). Fatal alert 

bulletins, fatalgrams and fatal investigation reports, 

1997–2000. [Data file]. Available: 

http://www.msha.gov/fatals/fab.htm. 

Moore, S.M., Porter, W.L., & Dempsey, P.G. (2009). Fall 

from equipment injuries in U.S. mining: 

Identification of specific research areas for future 

investigation. Journal of Safety Research, 40, 455-

460. 

National Institute for Occupational Health and Safety (2008). 

Mining Facts, Department of Human and Health 

Services, National Institute for Occupational Health 

and Safety, Publication No. 2008-158. 

Randolph, R. (1997). Safety analysis of surface haulage 

accidents – Part 1. Holmes Safety Association 

Bulletin, May-June, 1-7. 

Sanmiquel, L., Freijo, M., Edo, J., & Rossell, J.M. (2010). 

Analysis of work related accidents in the Spanish 

mining sector from 1982–2006. Journal of Safety 

Research, 41, 1-7. 

Truck and Bus Safety Summit (1995). Report of proceedings, 

Office of Motor Carriers, Federal Highway 

Administration, U.S. Department of Transportation, 

Washington, D.C. 

Turin, F.C., Wiehagen, W.J., Jaspal, J.S. & Mayton, A.G. 

(2001). Haulage truck dump site safety: An 

examination of reported injuries. (DHHS (NIOSH) 

Publication No. 2001–124, Information Circular 

9454). Pittsburgh, PA: U.S. Department of Health 

and Human Services, Public Health Services, Centers 

for Disease Control and Prevention, National 

Institute for Occupational Safety and Health. 

Wiehagen, W.J., Mayton, A.G., Jaspal, J.S. & Turin, F.C. 

(2001). An analysis of serious injuries to dozer 

operators in the U.S. mining industry. (DHHS 

(NIOSH) Publication No. 2001-126, Information 

Circular 9455). Pittsburgh, PA: U.S. Department of 

Health and Health Services, Public Health Services, 

Centers for Disease Control and Prevention, National 

Institute for Occupational Safety and Health.