PREVENTING EXPOSURE TO 

WHOLE-BODY 

VIBRATION

How vibration from heavy machinery affects operator 

health, and what you can do to minimize the intensity and 

frequency of these common events 

BY ALAN G. MAYTON AND DAN WIBLE

Haul trucks and front-end wheel loaders show the highest number of injuries related to 

jarring/jolting and whole-body vibration.

N

egative health effects of

exposure to whole-body

vibration are prevalent

in the industrial world 

today, particularly in 

mining where heavy 

earth-moving equipment and off-road 

vehicles are necessities. 

Heavy machinery produces whole-body 

vibration and mechanical shock 

exposure to equipment operators when 

operating on rough surfaces and under 

harsh conditions. This places a 

significant burden on the health and 

safety of exposed mine workers.

BASICS OF VIBRATION

Whole-body vibration exposure 

commonly occurs when a person is in 

contact with a vibrating surface – for 

example, while sitting on a vibrating 

seat, standing on a vibrating floor or 

lying on a vibrating bed or mat. Seated 

people exposed to whole-body 

vibration are also often simultaneously 

exposed to local vibration of the head 

(i.e., from a headrest), the hands (i.e., 

from a steering wheel) and the feet 

(i.e., from the floor). Vibration may 

also enter the body from contact with 

the seat backrest.

The primary characteristics of whole 

body vibration are vibration frequency,

magnitude, direction and duration. 

Vibration frequency is expressed as the 

reciprocal of the period in hertz (Hz). 

Magnitude is expressed as displacement, 

velocity or acceleration. In relation to the 

human body, direction is expressed in 

terms of vertical (head to foot), side to 

side (right to left) and back to chest. 

Duration is time interval of the exposure.

Humans are not typically exposed to 

vibration as a static, periodic signal in the 

real world. Instead, exposures include 

many simultaneous waves of varying 

frequency, magnitude, direction and 

duration. Therefore, the effects of wholebody vibration on the body of a mine 

worker are complex and can be 

substantial.

EFFECTS OF 

WHOLE-BODY VIBRATION

Evidence shows that cumulative 

exposure to whole-body vibration 

adversely impacts the health and safety 

of exposed mine workers. Moreover, 

whole-body vibration can contribute to 

the development of musculoskeletal 

disorders of the spine among exposed 

workers. A significant positive 

association between whole-body 

vibration exposure and low-back pain 

was reported by NIOSH in a review of 

19 research studies. A key finding 

showed a strong correlation between 

whole-body vibration and low-back 

pain in 15 of the 19 studies reviewed.

Mining equipment-induced vibration

72 PIT&QUARRY January 2019

KEVIN YANIK

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SAFETY
includes a broad range of frequency content and varies with time, depending on 

such factors as equipment type, task and 

operator skill. Exposure to such vibration 

can also cause fatigue or a lowering of 

motor performance capacity. 

Mechanical shock is an especially 

damaging form of whole-body vibration, 

since the mechanical energy is distributed 

over a range of frequencies. When vibration 

caused by shock is transmitted to a person 

at the natural resonant frequencies of the 

individual body parts or the body overall, 

amplifying resonance occurs. This effect 

causes body parts or the entire body to 

vibrate at a magnitude even greater than 

the applied vibratory force.

The frequency range considered important for whole-body vibration is 0.5 to 

80 Hz. A conventional bulldozer seat can 

show amplification of vibration magnitude 

between 3 and 7 Hz in the vertical (Z-axis) 

direction, from 2 to 20 Hz in the back to 

chest (X-axis) direction, and 4 to 15 Hz in 

the side to side (Y-axis) direction.

 

An illustration exhibits vibration in three directions: vertical (z), 

side to side (y) and back to chest (x).

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 January 2019

Symptoms experienced

Respiration complaints

General discomfort

Abdominal pain

Chest pain

Jaw resonance

Back pain

Constant urge to urinate 

and defecate

Pharynx disturbances

Headache

Increased muscle tension

Speech disturbances

Frequency range (Hz)

4-8

4-9

4-10

5-7

6-8

8-12

10-18

12-15

13-20

13-20

13-20

Source: after Magid and Coermann, 1960

MSHA INJURY STATS ON 

WHOLE-BODY VIBRATION

Injury statistics from the Mine Safety & 

Health Administration reveal important 

information relative to whole-body vibration. Between 2012 and 2016, surface 

mines and quarries reported a total of 523 

non-fatal days lost injuries and no-days-lost 

injuries related to the back, neck and head 

in the surface metal/nonmetal industry. 

These included cases with accident types 

of struck against a stationary object and 

struck against a moving object. 

Eighty-three percent (434) were non-fatal days lost. Metal operations reported the 

highest percentage at 39.8 percent of the 

523 non-fatal days lost and no-days-lost 

total injuries; stone operations reported 

the second highest percentage at 35.2 

percent; and sand and gravel operations 

at 13.6 percent.

Haul trucks, front-end wheel loaders 

and bulldozers show the highest number 

of injuries related to jarring/jolting and 

whole-body vibration: 330, 129 and 39, 

respectively. The body part most affected 

relative to these injuries was the back 

(426) and secondarily the neck (88). These

injuries can be characterized generally as

sprains and strains, which can result in

costly injury claims.

Using the Safety Pays in Mining website, 

the median cost per claim for a sprained 

back is estimated at $1,400 and could range 

from $540 to $31,800, with an average 

cost of $8,700. Similarly, the median cost 

per claim of a sprained neck is estimated 

at $1,700 and could range from $680 to 

$26,100, with an average cost of $18,000. 

Typical incidents of jarring and jolting 

were caused by running over rocks, ruts 

or potholes, running into other mobile 

machinery or equipment, being struck by 

other machinery and equipment rollovers. 

WAYS TO REDUCE WHOLE-BODY 

VIBRATION EXPOSURE

Researchers have identified preventive 

strategies to reduce vibration exposure to 

decrease the prevalence of musculoskeletal 

disorders for drivers and lower the incidence of low-back pain from whole-body 

vibration exposure. Various factors were 

identified for reducing exposure intensity, 

duration and the number of exposure 

intervals.

Investigators divided the factors into 

two groups: design considerations and 

skills and behavior. The seat and seat 

suspension; cabin suspension; location of 

the cabin; tire condition, pressure and type; 

load of the vehicle; and vehicle maintenance 

were designated as design considerations. 

The weight, posture and experience of the 

driver; seat adjustment; driving speed; track 

condition; working schedule; and fitness 

made up the skills and behavior category.

According to research findings, vibration magnitude is less for drivers who weigh 

more. Still, this finding only applies to 

MOBILE EQUIPMENT

SAFETY

NIOSH
 

smaller vehicles, such as forklifts and taxis.

Reduced vibration exposure levels have 

been reported when vehicle drivers sit in 

a neutral or upright position with their 

backs in full contact with the backrest 

and with lumbar support. Research has 

also shown that driving experience can 

result in lower vibration levels. 

Additionally, driving speed affects 

vibration exposure levels significantly in 

that increased speed results in increased 

vibration exposure levels. Moreover, driving speed appears to influence exposure 

level more so than road surface condition. 

Nevertheless, road surface condition does 

reduce vibration exposure magnitude 

effectively (i.e., a smooth dirt or gravel 

road surface in contrast to a rough road 

laden with potholes).

All factors combined from both categories had a lowering effect on vibration 

magnitude. In comparison to the design 

considerations, factors associated with 

the skills and behavior category were 

highlighted as a preferred option for mine 

and quarry managers and safety personnel 

to explore in the short term. These factors 

are generally less costly, more easily implemented and may provide a better option 

for short-term planning. 

On the other hand, design consideration 

factors may be better suited to the longterm interests and planning of a quarry 

operation.

Ideally, a successful intervention program that lowers exposures would include 

elements from both the design considerations and skills and behavior categories. 

Moreover, an intervention program has a 

greater likelihood of success if the scope 

and focus is limited to a specific group 

of drivers or a single driver or operator.

Thedevelopmentandimplementation 

of effective intervention programs is 

necessary to curtail the incidence of low 

back pain and other struck by/against 

injuriesindrivers andoperators exposed 

towhole-bodyvibration.Evaluatingthese 

programs in relation to both design considerations and skills and behavior is key 

to their success. P&Q

Alan G. Mayton is mining engineer at 

the National Institute for Occupational 

Safety & Health (NIOSH), and Dan 

Wible is safety director at Allegheny 

Mineral Corp. Note: The findings and 

conclusions in this article are those of 

the authors and do not necessarily 

represent the official position of the 

National Institute for Occupational 

Safety and Health, Centers for Disease 

Control and Prevention. Mention of any 

company or product does not constitute endorsement by NIOSH.

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SAFETY

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