. Author manuscript; available in PMC: 2015 Aug 7.

Published in final edited form as: Accid Anal Prev. 2012 Aug 11;50:778–786. doi: 10.1016/j.aap.2012.07.002

Table 1.

Descriptive statistics for variables in the 5669^a mine-year records used.

Variable	Value
Total number of all reported fatal and nonfatal injuries	87,080
Total number of reported nonfatal injuries with lost workdays	58,791
Total number of the most serious injuries reported, including fatalities	3423
Total number of hours worked	1.45 billion
Average incidence of all reported injuries per 100 FTE	12.81
Average incidence of reported injuries with lost workdays per 100 FTE	8.84
Average incidence of the most serious injuries reported per 100 FTE	0.67
Average real revenue per hours worked (indicator of profitability)	$43
Average mine age in years (tracked since 1983^b)	8.26
Unionized (%)	45.84
Longwall mining method (%)	15.86
Region^c (%)
North	15.73
Central	65.71
Midwest	9.74
West	6.44
South	2.38

Data were unbalanced. Information was available for only 25 mines (2.5%) for the entire 17-year-long period from 1992 to 2008.

Publically available MSHA data.

Data were assigned to one of five regions: North (PA, OH, MD, and northern WV), Central (southern WV, VA, TN, and eastern KY), Southern (AL), Midwest (western KY, IL, and IN), and West (all mines west of the Mississippi).