Analysis of non-fatal and fatal injury rates for mine operator and contractor employees and the influence of work location.
BACKGROUND
Mining injury surveillance data are used as the basis for assessing the severity of injuries among operator and contractor employees in the underground and surface mining of various minerals.


METHODS
Injury rates during 1983-2002 derived from Mine Safety and Health Administration (MSHA) database are analyzed using the negative binomial regression model. The logarithmic mean injury rate is expressed as a linear function of seven indicator variables representing Non-Coal Contractor, Metal Operator, Non Metal Operator, Stone Operator, Sand and Gravel Operator, Coal Contractor, and Work Location, and a continuous variable, RelYear, representing the relative year starting with 1983 as the base year.


RESULTS
Based on the model, the mean injury rate declined at a 1.69% annual rate, and the mean injury rate for work on the surface is 52.53% lower compared to the rate for work in the underground. With reference to the Coal Operator mean injury rate: the Non-Coal Contractor rate is 30.34% lower, the Metal Operator rate is 27.18% lower, the Non-Metal Operator rate is 37.51% lower, the Stone Operator rate is 23.44% lower, the Sand and Gravel Operator rate is 16.45% lower, and the Coal Contractor rate is 1.41% lower. Fatality rates during the same 20 year period are analyzed similarly using Poisson regression model. Based on this model, the mean fatality rate declined at a 3.17% annual rate, and the rate for work on the surface is 64.3% lower compared to the rate for work in the underground. With reference to the Coal Operator mean fatality rate: the Non-Coal Contractor rate is 234.81% higher, the Metal Operator rate is 5.79% lower, the Non-Metal Operator rate is 47.36% lower, the Stone Operator rate is 8.29% higher, the Sand and Gravel Operator rate is 60.32% higher, and the Coal Contractor rate is 129.54% higher.
Karra
Vijia K
VK
National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory, Cochrans Mill Road, P.O. Box 18070, Pittsburgh, PA 15236, USA. vkarra@cdc.gov
D000062:Accidents, Occupational / Q000401:mortality / Q000706:statistics & numerical data*; D019992:Databases as Topic; D006801:Humans; D008906:Mining; D015233:Models, Statistical; D012044:Regression Analysis; D014481:United States / Q000453:epidemiology; D014947:Wounds and Injuries / Q000453:epidemiology* / Q000401:mortality