RISK PROFILE OF CUMULATIVE TRAUMA DISORDERS OF THE ARM
AND HAND IN THE U.S. MINING INDUSTRY

By S. D. Hudock’ and C. M. Keran?

ABSTRACT

A review of all upper extremity cumulative trauma disorder (UECTD) injuries was conducted by the
U.S. Bureau of Mines for 1985 through 1989, This review was performed by analyzing each injury, as
reported by law and maintained on the U.S. Mine Safety and Health Administration’s accident data
base. This analysis found that incidence rates in mining were lower than in private sector industry,
although the number of reported UECTD injuries increased sevenfold and their percentage of all mining
injuries increased fivefold from 1985 through 1989. Metal-nonmetal mines accounted for 80 pct of
UECTD injuries, while coal mines accounted for 20 pet. Nearly 63 pct of UECTD injuries were
accounted for by only four occupations—mechanics, laborers, boney (crusher) operators, and miners not
elsewhere classified (NEC)—with an incidence rate well above the private sector industry rate.

\Safety engineer (now with National Institute for Occupational Safety and Health, Cincinnati, OH).
Engineering research psychologist.
‘Twin Cities Research Center, U.S. Bureau of Mines, Minneapolis, MN.


80.5 pct of the injuries occurred in metal-nonmetal mines,
whereas 19.5 pet occurred in coal mines. In 1986, there
were an estimated 166,406 metal-nonmetal mine personnel
(excluding office personnel) working in 10,600 metal-
nonmetal mines and an estimated 145,691 coal mine per-
sonnel (excluding office personnel) working in 7,750 coal
mines (19-20). The total number of UECTD injuries for
1989 yields an incidence rate of 6.3 per 10,000 metal-
nonmetal miners and 1.8 per 10,000 coal miners. Inci-
dence rates represent the number of illnesses per 10,000
full-time workers (27) and are calculated as (N/EH) x 20
million, where N = number of illnesses, EH = total hours
worked by all employees during the calendar year, and
20 million = base for 10,000 equivalent full-time em-
ployees working 40 h per week, 50 weeks per year.

The average age of the mining work force in 1986 was
39.5 years (19-20). For that same year, the average age of
miners with CTD injuries was 38.2 (N = 11), and for those
with CTS, the average age was 40.5 years (N = 15).

The average amount of experience at the job for the
entire mining population in 1986 was 4.5 years (19-20).
For that same year, the average years of experience at the

job for miners with CTD injuries was 4.6, and for those
with CTS, the average was 10.3 years.

Of the 45 mining occupations that have experienced a
CTD during the period 1985 through 1989, four occupa-
tions comprise 62.7 pct of all reported CTD’s (N = 263).
Encompassing approximately 13 pet of the mining work
force (19-20), the UECTD injuries that these selected
occupations contribute are mechanics, 14.6 pet; laborers,
15.5 pet; boney (crusher) operators, 24.4 pet; and miners
NEG, 8.2 pet. The total number of UECTD injuries for
1989 for these four occupations yields an incidence rate of
30.4 per 10,000 selected metal-nonmetal miners and 8.7
per 10,000 selected coal miners.

According to the U.S. Bureau of Labor Statistics (21),
the illness incidence rate for disorders associated with
repeated trauma in private sector industry was 19.2 per
10,000 workers. The highest incidence rate was for manu-
facturing, at 68.9. These rates include repeated trauma in-
juries to any affected body part, including the upper and
lower extremities, ear drum (noise-induced hearing loss),
and the back, whereas the mining data only include upper
extremity repeated trauma disorders.

DISCUSSION

The total number of UECTD injuries reported during
the period 1985 through 1989 increased as well as the
percentage of UECTD injuries that comprised all mining
accidents.

Metal-nonmetal mine workers had more than four
times as many UECTD injuries than coal mine workers
from 1985 through 1989.

The existence of a CTD appears to have no relationship
with age nor mining experience, although those with CTS
tended to have more experience than the general mining
work force.

Although the mining sector had low incidence rates,
certain mining occupations did experience higher-than-
normal incidence rates. In fact, almost two-thirds of all
reported CTD injuries during the period 1985 through
1989 were attributed to only four occupations: mechanics,
laborers, boney (crusher) operators, and miners NEC.
These four occupations comprised only about one-seventh
of the mining work force and had an incidence rate well
above the private sector industry rate.

CONCLUSIONS

Awareness of a problem is critical for the alleviation of
it. Awareness of CTD’s in mining is apparently evident,
since more and more injuries are being reported every
year. Although incidence rates for CTD’s in mining are
generally lower than in private sector industry, there are
certain occupations, in metal-nonmetal mines specifically,

that have a greater incidence rate than in private sector
industry. Future investigations should identify the specific
risk factors associated with these occupations in metal-
nonmetal mines [ie., mechanics, laborers, boney (crusher)
operators, and miners NEC] that experience a high inci-
dence rate of CTD’s.


CONTENTS

Abstract 6.6... e eee e ee eee eee
Introduction . .

Method .
Results
Discussion .
Conclusions .
References

ILLUSTRATIONS

1, UECTD injuries in the U.S. mining industry, 1985 through 1989 ....
2. UECTD injuries per 1,000 injuries in the U.S. mining industry, 1985 through

TABLE

1, Common UECTD’s .....

Page

UbRYONE


INTRODUCTION

Cumulative trauma disorders (CTD’s) are injuries that
develop gradually over a period of time, ranging from
weeks to months, as a result of repeated stress to a par-
ticular body part without adequate time between stresses
for full recovery to occur. CTD’s, also known as repetitive
motion or repetitive strain injuries, have long been thought
to be work related (1-4)3 There is increasing concern
about the long-term effects on clerical personnel working
on word processing equipment for long hours each day.
Automotive assembly personnel often work in awkward
postures to install the same components continuously
throughout the shift. Mine workers are also exposed to a
combination of stressors and work design deficiencies
that result in arm and hand injuries. For example, certain
job tasks and locations, such as that of an underground
jackleg driller, expose miners to cold temperatures and
segmental (hand-arm) vibration. In fact, vibration white
finger syndrome, also known as hand-arm vibration syn-
drome, is an occupational CTD common to underground
hand-held drill operators, especially in hard-rock mining
operations (5). Operators of underground mobile equip-
ment, such as scoops and trams, regularly have their hands
in direct contact with vibrating levers and controls. The
same is true of those operating larger jumbo drills and
raise borers. Workers at mills, particularly in bagging
and palletizing operations, must repetitiously move rock
products weighing from 5 to 75 Ib, which can contribute to
back injuries.

While CTD’s occur primarily to the hands, arms, legs,
and back, this Information Circular (IC) is concerned with
those CTD’s effecting only the hands and arms, referred
to as UECTD injuries. A summary of common UECTD’s
is provided in table 1. The stresses that contribute to
UECTD’s may occur because of the following work com-
ponents: awkward position of wrist or arm, excessive
manual force, high repetitions of manual movement and
effort, cold environment, and vibration (6-9).

Carpal tunnel syndrome (CTS) appears to be the most
widely known UECTD. This disorder occurs in part be-
cause of the anatomical structure of the human wrist. The
major muscles that flex the fingers and allow humans to
grasp and manipulate objects are called flexor forearm
muscles. The tendons that connect these muscles to the
bones in the hands and fingers run through the wrist be-
tween the carpal ligament and the wrist bones. Also run-
ning through this carpal tunnel is the median nerve, which
is responsible for most motor responses and sensations felt
in the thumb and first three fingers of the hand, primarily
on the palm side. CTS develops when any of the sheaths

3{talic numbers in parentheses refer to items in the list of references
at the end of this report.

of the finger flexor tendons within the wrist become irri-
tated and swell, pressing against the median nerve. The
resulting pain, numbness, and tingling of the hands are
often more noticeable while asleep, which wakes the indi-
vidual up and disturbs sleep. Advanced cases of CTS may
include apparent clumsiness and weakness in the hands, as
well as a deterioration of the muscles at the base of the
thumb.

Table 1.—Common UECTD’s (6)

Disorder

Description

Inflammation, fraying, or
tearing of tendon
fibers.

Tendon sheath inflam-
mation and swelling.

Tendon sheath swells
and constricts move-
ment (DeQuervain's
disease),

‘Swollen sheath locks
tendon, resulting in
jerking movement (trig-
ger finger).

‘Sheath swollen with
fluid,

Irritated unsheathed ten-
don on outer side of
elbow (tennis elbow).

Irritated unsheathed ten-
don on inner side of
elbow (golfer’s elbow),

Shoulder tendon
disorder.

Compression of median
nerve by swollen finger
flexor tendons in the
wrist, resulting in pain,
numbness, and tin
gling in hands.

Tenosynovitis...... 02... cece ee

Stenosing tenosynovitis .........

Stenosing tenosynovitis crepitans . .

Ganglionic cyst ...... 26.000 005

Lateral epicondylitis ............

Medial epicondylitis ............

Neurovascular:

Thoracic outlet syndrome ........ Compression of the
nerves and blood ves-
sels between the neck
and shoulder often due
to repeated reaching
above shoulder level.

Numbness, tingling, and
blanching of fingers
due to closure of digi-
tal arteries often
caused by extended
use of vibrating hand
tools and controls.

Vibration white finger syndrome . . .


REFERENCES

1. Agate, J.N. An Outbreak of Cases of Raynaud’s Phenomenon of
Occupational Origin. Brit. J. Ind. Med., v. 6, 1949, pp. 144-163.

2. Ashe, W. F., W. T. Cook, and J. W. Old. Raynaud’s Phenomenon
of Occupational Origin. Arch. Environ. Health, v. 5, 1966, pp. 333-343.

3. Hunter, D., A. I. G. McLaughlin, and K. M. A. Perry. Clinical
Effects of the Use of Pneumatic Tools. Brit. J. Ind. Med,, v. 2, No. 1,
1945, pp. 10-15.

4. McLaren, J. W. Disability of Workers Using Pneumatic Drills.
With Special Reference to the Radiological Changes. Lancet, v. 2, 1937,
Pp. 1296-1299,

5. National Institute for Occupational Safety and Health (Dep.
Health and Human Serv., Cincinatti, OH). Criteria for a Recom-
mended Standard: Occupational Exposure to Hand-Arm Vibration.
DHHS Publ. 89-106, Sept. 1989, 127 pp.

6. Putz-Anderson, V. (ed.). Cumulative Trauma Disorders: A
Manual for Musculoskeletal Diseases of the Upper Limb. Taylor &
Francis (Philadelphia), 1988, 149 pp.

7. Streib, E. W., and S. F. Sun. Distal Ulnar Neuropathy in Meat
Packers: An Occupational Disease. J. Occup. Med., v. 26, No. 11, 1984,
pp. 842-843,

8 Viikari, J. E. Neck and Upper Limb Disorders Among
Slaughterhouse Workers—An Epidemiologic and Clinical Study. Scand.
J. Work, Environ. and Health, v. 9, No. 3, 1983, pp. 283-290.

9. Wallersteiner, U. Workplace Factors Contributing to the Mus-
culoskeletal Disorders of Meat Process Workers. Paper in Proceedings
of the Annual Conference of the Human Factors Association of Canada.
Hum. Factors Assoc. Can., Toronto, 1988, pp. 105-107.

10, Hagberg, M., and D. H. Wegman. Prevalence Rates and Odds
Ratios of Shoulder-Neck Diseases in Different Occupational Groups.
Brit. J. Ind. Med,, v. 44, No. 9, 1987, pp. 370-374.

11. Jonsson, B. G., J. Persson, and A. Kilbom. Disorders of the
Cervicobrachial Region Among Female Workers in the Electronics
Industry. Int. J. Ind. Ergon., v. 3, No. 1, 1988, pp. 1-12.

12. Kumar, S. Upper Extremity Morbidity in a Garment Industry.
‘Adv. in Ind. Ergon. and Saf. I, ed. by A. Mital. Taylor & Francis
(Philadelphia), 1989, pp. 47-55.

13. Schlegel, R. E., and R. Wilcoxon. An Ergonomic Evaluation of
Powered Hand Tool Use in Automobile Assembly. Adv. in Ind. Ergon.
and Saf. I, ed. by A. Mital. Taylor & Francis (Philadelphia), 1989,
PP. 267-274.

14. Soltaniuk, L. A., and I. J. Fraser. An Investigation of Alberta
WCB Claims for the Extent and Nature of Work-Related Repetitive
Strain Injuries of the Upper Extremity and Neck. Paper in Proceedings
of the Annual Conference of the Human Factors Association of Canada.
‘Hum, Factors Assoc. Can., Toronto, 1988, pp. 77-80.

15. Welch, R. The Causes of Tenosynovitis in Industry. Ind. Med.,
v. 41, No. 10, 1972, pp. 16-19.

16. Occupational Health & Safety News. Empire Kosher Will
Develop Ergonomics Pian. V. 5, No. 11, July 15, 1989, p. 3.

17. . ConAgra’s "Low Priority" Prompts OSHA Penalties. V. 5,
No. 11, July 15, 1989, pp. 1-2.

18. . Sara Lee Agrees To Reduce Hazards. V. 5, No. 16, Oct.
1, 1989, p. 11.

19, Butani, S. J, and A. M. Bartholomew. Characterization of the
1986 Coal Mining Workforce. BuMines IC 9192, 1988, 63 pp.

20. . Characterization of the 1986 Metal and Nonmetal Mining
Workforce. BuMines IC 9193, 1988, 5S pp.

21. U.S. Department of Labor. Occupational Injuries and Ilinesses
in the United States by Industry. Labor Stat., 1989, p. 42.



BUREAU OF MINES
IC} 9319 INFORMATION CIRCULAR/1992

Risk Profile of Cumulative Trauma
Disorders of the Arm and Hand in
the U.S. Mining Industry

By S. D. Hudock and C. M. Keran

5S

| | | hil

UNITED STATES DEPARTMENT OF THE INTERIOR



CTD’s to the arm and hand have become an ever grow-
ing concern among safety and health professionals in a
number of different industries and work settings (10-15).
Meatpacking operations, assembly-line work, and key-
boarding have all been associated with the development
of CTS. Numerous substantial fines have recently been
levied by both the Federal Occupational Safety and
Health Administration (OSHA) and State equivalents on

meatpacking operations in an effort to curtail cumulative
trauma injuries to the arm and hand (16-18).

The extent of UECTD’s in the mining industry has not
been previously determined. As part of the U.S. Bureau
of Mines ongoing health and safety research to reduce
CTD’s in mining, prevalence and incidence rates of
UECTD’s in the U.S. mining industry from 1985 through
1989 were determined and comparisons to other industries
were made.

METHOD

Mining accident information is maintained in a com-
puterized data base by the U.S. Mine Safety and Health
Administration’s Denver Safety and Health Technology
Center for all reportable U.S. mining accidents, injuries,
and illnesses that have occurred since 1978. This data
base provides information about the injury: type, severity,
date, time, etc.; the injured: age, occupation, job experi-
ence, and other demographic information; and the mine:
type, location, number of employees, etc. A five-line nar-
rative of each incident is also available.

The 5-year period from 1985 through 1989 was selected
for analysis. The injuries were selected by specifying
irritated tendon injuries and occupational diseases to the
upper extremities for both coal and metal-nonmetal mining
accidents. The narrative from each of the injuries was

then analyzed by the primary author to determine if the
injury was due to an acute incident (i.c., struck by object)
or to a cumulative trauma, Acute injuries were excluded
from all analyses, CTD’s were divided into two groups:
(1) CTS injuries (identified by a CTS diagnosis or surgery
notation within the narrative) and (2) CTD injuries ex-
cluding CTS (hereafter referred to as CTD injuries). To
reduce CTD’s in mining, this study examined whether age,
years of work experience, or job title are significant factors
in the development of UECTD injuries in mining, with
special emphasis on CTS injuries. Also, a comparison was
made of the incidence rates in mining to those of private
sector industry. (Statistical tests of private sector industry
were infeasible since the U.S. Bureau of Labor Statistics
does not report the standard deviation of the mean.)

RESULTS

The number of CTS and CTD’s occurring from 1985
through 1989 are shown in figure 1. The number of re-
ported CTD’s increased from 6 in 1985 to 59 in 1989. The
number of reported CTS injuries increased from 9 in 1985
to 72 in 1989, The ratio of CTS and CTD’s to all mining
accidents is illustrated in figure 2 according to injury and
year. Both curves show an increasing trend.

20 ~
KEY

crs
CTD (without CTS)

NUMBER

This increasing trend may be due to increasing occur-
rences of CTD’s, or more likely, CTD’s are increasingly
being reported. In either case, it is important to know
who the workers are that are being injured. Out of a total
263 reported CTD’s during the period 1985 through 1989,

25 1 T T

KEY
—— Ts

—— ID (without cTs)

NUMBER

L 1

° 1
1985 7986 1387 1988 7989

Figure 1.—UECTD Injuri
through 1989.

in the U.S. mining Industry, 1985

° n
1985 1986 1987 «1988, 1989

Figure 2—UECTD injuries per 1,000 Injuries In the U.S. mining
Industry, 1985 through 1989.


Information Circular 9319

Risk Profile of Cumulative Trauma
Disorders of the Arm and Hand in
the U.S. Mining Industry

By S. D. Hudock and C. M. Keran

UNITED STATES DEPARTMENT OF THE INTERIOR
Manuel Lujan, Jr., Secretary

BUREAU OF MINES
TS Ary, Director


Library of Congress Cataloging in Publication Data:

Hudock, S. D.
Risk profile of cumulative trauma disorders of the arm and hand in the U.S.
mining industry / by S.D. Hudock and C.M. Keran.

p. cm. — (Information circular, 9319)
Includes bibliographical references (p. 5).

Supt. of Docs. no.: I

1. Miners—Health and hygiene. 2. Extremities, Upper—-Wounds and injuries.
3. Occupational diseases. 4. Overuse injuries. 5. Disability evaluation. I. Keran,
C. M. (Christopher M.). II. Title. II. Series: Information circular (United States.
Bureau of Mines); 9319.

[DNLM: 1. Accidents, Occupational—United States. 2. Arm Injuries—
epidemiology—United States. 3. Hand Injuries—epidemiology—United States.
4, Mining—United States. 5. Repetition Strain Injury—epidemiology—Unites States.
6. Risk Factors. WE 805 H884r]

TN295.U4 [RC965.M48] 622 s—dc20 [617.5°74044]
DNLM/DLC for Library of Congress 92-15539 CIP