Mine Safety and Health Administration
Accident Injury Rates Calculations

Injury rates are calculated by a formula. This formula involves production hours and accidents. Accidents are reported as they occur. By law, production information, to include hours, is due to MSHA on a quarterly basis. It is due within 15 days after the end of the quarter. Quarters run January - March (1), April - June (2), July - September (3), and October - December (4). MSHA then has to process this information. The end result of both of these things is that accidents are real-time data and production is delayed information. If we calculated injury rates using both the current accident information and the available production information incidence rates for "current quarters" would be skewed. We have implemented code that will only provide the actual rates. This is done by only comparing accidents that have occured during the completed production reporting period. Completed for this process is 60 days after the end of the last production reporting period.

Formula for calculating injury rates:

Current Number of Fatals or Nonfatal Accidents for the year X 200,000 hours divided by Current Mine Hours = Injury Rate

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