Underground and Surface Mining Facts - 2008 (HTML)
DHHS (NIOSH) Publication No. 2011–162
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. 
A total of 59,922 employees,  or 62,565 full-time equivalent (FTE)  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. 
- 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%).
- Coal operators were the mining sector  reporting the most underground worker employee hours to MSHA (n=91,732,062; 73.3%).
|Commodity and Type|
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.
|Sand and Gravel Operator||0|
|Sand and Gravel Operator||9|
Nonfatal Lost-time Injuries
Within underground work locations, 2,600 nonfatal lost-time injuries were reported, resulting in 152,273 days lost from work.  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.
|Year||Underground||Surface||Underground Rate||Surface Rate|
Mining operations, 2008
|Commodity and Type of Employer||Underground Mining Operations ||Surface Mining Operations ||Total Mining Operations |
|Sand & Gravel||Not applicable||7,132||7,132|
Contracting companies, 2008
|Commodity and Type of Employer||Number of Companies|
Employment characteristics, 2008
|Commodity and Type of Employer||Underground Employees ||Surface Employees ||Total Employees ||Underground FTE Employees ||Surface FTE Employees ||Total FTE Employees |
|Sand & Gravel Operator||Not applicable||42,307||42,307||Not applicable||33,343||33,343|
Mining Occupational Fatalities (per 100,000 FTE employees), 2008
|Commodity and Type of Employer||Underground Fatalities||Underground Fatality Rate||Surface Fatalities||Surface Fatality Rate||Fatalities||Fatality Rate|
|Metal Operator||3||Not calculated||2||Not calculated||5||13.8|
|Nonmetal Operator||1||Not calculated||1||Not calculated||2||Not calculated|
|Stone Operator||1||Not calculated||6||9.4||7||10.6|
|Sand & Gravel Operator||Not applicable||Not applicable||3||Not calculated||3||Not calculated|
|Coal Contractor||3||Not calculated||9||43.4||12||48.3|
|Noncoal Contractor||0||Not calculated||5||13.9||5||13.2|
|Contractor Total||3||Not calculated||14||24.7||17||27.1|
Nonfatal Lost-time Injuries (per 100 FTE employees), 2008
|Commodity and Type of Employer||Underground Injuries||Underground Injury Rate||Surface Injuries||Surface Injury Rate||Injuries||Injury Rate|
|Sand & Gravel Operator||Not applicable||Not applicable||550||1.9||550||1.9|
Not calculated when N is less than 5. 95% CI for rates reported above. 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. Caution should be used when interpreting rates based on a small number of events.
- Mines at which only independent contractors were working did not show any employment and were not counted.
- Average number of employees working at individual mines during calendar quarters of active operations (includes office workers).
- Full-time equivalent employees computed using reported employee hours (2,000 hours = 1 FTE).
- 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.
- Mining sectors include coal operators, metal operators, nonmetal operators, stone operators, sand and gravel operators, coal contractors, and noncoal contractors.
- 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.
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- Page last reviewed: 3/2/2015
- Page last updated: 3/26/2014
- Content source: National Institute for Occupational Safety and Health, Mining Program