UNDERGROUND AND SURFACE 

MINING FACTS–2008

DEPARTMENT OF HEALTH AND HUMAN SERVICES 

Centers for Disease Control and Prevention 

National Institute for Occupational Safety and Health 

March 2011

Mining Operations 

Data obtained from the Mine Safety and Health 

Administration (MSHA) indicated a total of 925 

underground (6.2%) and 13,982 surface (93.8%) 

mining operations.1

Employees 

A total of 59,922 employees,2 or 62,565 full-time 

equivalent (FTE)3 employees, were reported to MSHA 

as working at underground mining locations in 2008. 

This is in contrast to 332,797 employees (or 278,054 

FTE employees) who were reported as working at 

surface locations.4

Surface work location employee hours accounted for 

81.6% of all hours reported to MSHA, while 18.4% 

of employee hours were reported for underground 

work locations. 

The majority of surface employee hours were for 

mine operator employees (78.3%) as opposed to 

independent contractor employees (21.7%).

5 Coal operators were the mining sector reporting 

the most underground worker employee hours to 

MSHA (n=91,732,062; 73.3%).

0

100

200

300

400

500

600

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 Number of Employee Hours (millions)

Surface Work Locations

Underground Work Locations

Fatalities 

Of the 52 occupational mining fatalities reported to 

MSHA in 2008, 20 occurred at underground work 

locations, while 32 occurred at surface locations. 

The fatality rate of 32.0 [95% confidence interval 

(CI): 19.5, 49.4] per 100,000 FTE employees was 

higher at underground work locations, compared to 

the rate of 12.9 [CI: 8.8, 18.3] for surface work 

locations. 

Coal Operator Metal Operator

Nonmetal Operator Stone Operator

Sand & Gravel Operator Coal Contractor

Noncoal Contractor

Surf UG 61%

39%

Underground Surface

Distribution of Occupational Mining Fatalities

Nonfatal Lost-time Injuries 

Within underground work locations, 2,600 nonfatal losttime injuries were reported, resulting in 152,273 days lost 

from work.6 This compares to 4,748 nonfatal lost-time 

injuries attributed to surface workers resulting in 229,937 

days lost from work. 

The overall underground nonfatal lost-time injury 

rate was greater than the surface injury rate (4.2 [CI: 

4.0, 4.3] vs. 1.9 [CI: 1.9, 2.0] per 100 FTE workers). 

The most frequent classification of nonfatal lost-time 

injuries involved handling materials for both 

underground (n=734; 28.2%) and surface (n=1,566; 

33.0%) work locations. 

The back was the most frequently reported body part 

injured at both underground (n=384; 14.8%) and 

surface (n=856; 18.0%) work locations.

0

2,000

4,000

6,000

8,000

10,000

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 Number of Nonfatal Lost-time Injuries

0

2

4

6

8

10 Nonfatal Lost-time Injury Rate (per 100 Full-time Equivalent Employees)

Underground Surface UG Rate Surf Rate
Mine and Employment Characteristics, 2008

1 2 3 Commodity and Number of Mining Operations Number of Employees Number of FTE Employees

Type of Employer Underground Surface Total Underground Surface Total Underground Surface Total 

Coal Operator 665 1,464 2,129 40,370 49,685 90,055 45,866 54,312 100,178

Metal Operator 105 188 293 5,844 33,282 39,126 5,842 34,840 40,682

Nonmetal Operator 44 676 720 2,579 20,454 23,033 2,725 20,534 23,260

Stone Operator 111 4,522 4,633 1,875 77,100 78,975 2,029 74,720 76,749

Sand and Gravel Operator NA 7,132 7,132 NA 42,307 42,307 NA 33,343 33,343

Operator Total 925 13,982 14,907 50,668 222,828 273,496 56,462 217,750 274,212

Number of Companies

Coal Contractor NA NA 3,467 6,262 37,510 43,772 4,105 22,216 26,321

Noncoal Contractor NA NA 6,128 2,992 72,459 75,451 1,998 38,088 40,086

Contractor Total NA NA 9,595 9,254 109,969 119,223 6,103 60,304 66,407

 59,922 332,797 392,719 62,565 278,054 340,620

Commodity and 

Type of Employer

Coal Operator 12 26.2 6 11.9 18 18.7 2,103 4.6 768 1.5 2,871 3.0

Metal Operator 3 NC 2 NC 5 13.8 163 2.8 649 2.1 812 2.2

Nonmetal Operator 1 NC 1 NC 2 NC 95 3.5 412 2.4 507 2.5

Stone Operator 1 NC 6 9.4 7 10.6 33 1.6 1,593 2.5 1,626 2.5

Sand and Gravel Operator NA NA 3 NC 3 NC NA NA 550 1.9 550 1.9

Operator Total 17 30.1 18 9.4 35 14.2 2,394 4.2 3,972 2.1 6,366 2.6

Coal Contractor 3 NC 9 43.4 12 48.3 168 4.1 313 1.5 481 1.9

Noncoal Contractor 0 NC 5 13.9 5 13.2 38 1.9 463 1.3 501 1.3

Contractor Total 3 NC 14 24.7 17 27.1 206 3.4 776 1.4 982 1.6

TOTAL 20 32.0 32 12.9 52 16.8 2,600 4.2 4,748 1.9 7,348 2.4

Mining Occupational Fatalities and Injuries, 2008

Total Underground Surface Total

Nonfatal Lost-time Injuries (per 100 FTE employees)

Rate Rate No. Rate No. Rate No. Rate 

Occupational Fatalities (per 100,000 FTE employees)

Underground Surface

 No. No. Rate No.

NA Not applicable. NC Not calculated when N is less than 5. 95% CI for rates reported on reverse side. Totals may not sum due to independent rounding. 

Data source: Publicly released employment and accident/injury/illness data collected by MSHA under 30 CFR 50. 

Notes: All analyses of accident data exclude office employees. Occupational fatalities exclude all cases under 17 years of age. Further 

statistical methodology is available on the NIOSH Internet [http://www.cdc.gov/niosh/mining/statistics/method.htm]. Caution should be 

used when interpreting rates based on a small number of events. 

1Mines at which only independent contractors were working and did not show any employment were not counted. 

2Average number of employees working at individual mines during calendar quarters of active operations (includes office workers). 

3

Full-time equivalent employees computed using reported employee hours (2,000 hours = 1 FTE). 

4

Surface work locations include surface operations at underground mines, surface operations (strip or open pit), auger, culm banks, 

 dredge, other surface operations, independent shops and yards, and mills or preparation plants. 

5Mining sectors include coal operators, metal operators, nonmetal operators, stone operators, sand and gravel operators, coal contractors, 

 and noncoal contractors. 

6

Includes actual days away from work and/or days of restricted work activity. For permanently disabling injuries only, statutory days 

charged by MSHA were used if they exceeded the total lost workdays. 

To receive documents or other information about 

occupational safety and health topics, contact NIOSH at 

Telephone: 1–800–CDC–INFO (1–800–232–4636) 

TTY: 1–888–232–6348

E-mail: cdcinfo@cdc.gov

or visit the NIOSH Web site at www.cdc.gov/niosh. 

DHHS (NIOSH) Publication No. 2011–162