DEPARTMENT OF HEALTH AND HUMAN SERVICES

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health

September 2008

UNDERGROUND AND SURFACE 

MINING FACTS – 2006

Mining Operations

In 2006, data obtained from the Mine Safety and 

Health Administration (MSHA) indicated a total of

935 underground (6.3%) and 13,950 surface (93.7%) 

mining operations.

1

Employees

A total of 53,620 employees,

2

or 56,046 full-time 

equivalent (FTE)3employees, were reported to 

MSHA as working at underground mining locations 

in 2006. This is in contrast to 309,877 employees (or 

275,212 FTE employees) that were reported as 

working at surface locations.4

Surface work location employee hours accounted 

for 83.1% of all hours reported to MSHA, while 

16.9% of employee hours were reported for 

underground work locations.

0

100

200

300

400

500

600

700

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Number of Employee Hours (millions)

All Work Locations

Surface Work Locations

Underground Work Locations

Note: Beginning with the 2006 Mining Fact Sheets, hours reported to MSHA for office 

employees are included in number of employee hours.

The majority of surface employee hours were for 

mine operator employees (81.8%) as opposed to 

independent contractor employees (18.2%).

Coal operators were the mining sector5reporting 

the most underground worker employee hours to 

MSHA (n=85,195,306; 76.0%).

Fatalities

Of the 73 occupational mining fatalities reported to 

MSHA in 2006, 37 occurred at underground work 

locations, while 36 occurred at surface locations.

The fatality rate of 66.0 per 100,000 FTE 

employees was higher at underground work 

locations, compared to the rate of 14.6 for

surface work locations.

Coal Operator Metal Operator

Nonmetal Operator Stone Operator

Sand & Gravel Operator Coal Contractor

Noncoal Contractor

UG

35%

Surf

65%

Underground Surface

Distribution of Mining Fatalities

2002-2006

Nonfatal Lost-time Injuries

Within underground work locations, 2,739 nonfatal 

lost-time injuries were reported, resulting in 172,539

lost workdays.

6

 This compares to 5,249 nonfatal

lost-time injuries attributed to surface workers (total 

days lost=267,203). 

The overall underground nonfatal lost-time 

injury rate was greater than the surface injury

rate (4.9 vs. 2.1 per 100 FTE workers). 

0

2,000

4,000

6,000

8,000

10,000

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 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

The most frequent classifications of nonfatal 

lost-time injuries involved handling materials for 

both underground (n=810; 29.6%) and surface 

(n=1,845; 35.1%) work locations. 

The back was the most frequently reported body 

part injured at both underground (n=503; 18.4%) 

and surface (n=981; 18.7%) work locations. 
To receive NIOSH documents or for more information about

occupational safety and health topics, contact NIOSH at

1–800–CDC–INFO (1–800–232–4636)

1–888–232–6348 (TTY)

e-mail: cdcinfo@cdc.gov

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

DHHS (NIOSH) Publication No. 2008-166

Commodity and 

Type of Employer Surface Total Surface Total Surface Total 

Coal Operator 675 1,438 2,113 38,253 47,440 85,693 42,598 51,897 94,495

Metal Operator 92 188 280 4,539 28,335 32,874 4,575 29,397 33,972

Nonmetal Operator 46 695 741 2,374 20,677 23,051 2,415 20,806 23,221

Stone Operator 122 4,451 4,573 1,877 80,706 82,583 2,154 83,247 85,402

Sand and Gravel Operator NA 7,178 7,178 NA 46,069 46,069 NA 39,796 39,796

Operator Total 935 13,950 14,885 47,043 223,227 270,270 51,742 225,144 276,886

Coal Contractor NA NA 2,724 4,762 32,520 37,282 2,903 20,175 23,078

Noncoal Contractor NA NA 4,686 1,815 54,130 55,945 1,401 29,893 31,294

Contractor Total NA NA 7,410 6,577 86,650 93,227 4,304 50,068 54,372

TOTAL 53,620 309,877 363,497 56,046 275,212 331,258

Number of Mining Operations1 Number of Employees2 Number of FTE Employees3

Mine and Employment Characteristics, 2006

Number of Companies

Underground Underground Underground Commodity and 

Type of Employer

Coal Operator 36 84.5 6 12.4 42 46.2 2,218 5.2 803 1.7 3,021 3.3

Metal Operator 0 0.0 3 11.9 3 10.1 141 3.1 524 2.1 665 2.2

Nonmetal Operator 0 0.0 0 0.0 0 0.0 73 3.0 344 2.0 417 2.1

Stone Operator 0 0.0 10 13.8 10 13.4 43 2.0 2,038 2.8 2,081 2.8

Sand and Gravel Operator NA NA 6 17.2 6 17.2 NA NA 795 2.3 795 2.3

Operator Total 36 69.6 25 12.6 61 24.4 2,475 4.8 4,504 2.3 6,979 2.8

Coal Contractor 1 34.4 4 20.9 5 22.7 215 7.4 342 1.8 557 2.5

Noncoal Contractor 0 0.0 7 24.8 7 23.6 49 3.5 403 1.4 452 1.5

Contractor Total 1 23.2 11 23.2 12 23.2 264 6.1 745 1.6 1,009 2.0

TOTAL 37 66.0 36 14.6 73 24.2 2,739 4.9 5,249 2.1 7,988 2.6

Mining Occupational Fatalities and Injuries, 2006

Total Underground Surface Total

Occupational Fatalities (per 100,000 FTE employees) Nonfatal Lost-time Injuries (per 100 FTE employees)

Underground Surface

 No. Rate No. Rate No. Rate No. Rate No. Rate No. Rate 

NA Not applicable.

Data source: Publicly released data files of employment and accident/injury/illness 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].

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

2Number of employees is the average number of employees working at individual mines during calendar quarters of active operations.

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: 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.