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Evaluating the effectiveness of mine safety enforcement actions in forecasting the lost-days rate at specific worksites (Gernand 2016)

Absence of conflict of interest.

Citation

Gernand, J. M. (2016). Evaluating the effectiveness of mine safety enforcement actions in forecasting the lost-days rate at specific worksites. Journal of Risk and Uncertainty in Engineering Systems, 2(4). https://doi.org/10.1115/1.4032929

Highlights

  • The study’s objective was to examine the impact of Mine Safety and Health Administration (MSHA) inspection violations on future accidents and injuries in underground coal mines.
  • The author used statistical models and publicly available MSHA data to predict whether a non-fatal or severe disabling injury would occur in the 12 months following an infraction.
  • The study found that the rate of lost-time injuries could be significantly predicted by total worker time at the mine and the average penalty assessed by MSHA, with a lower likelihood of injury with increased number of worker days at the mine and higher penalties per violation.
  • The quality of causal evidence presented in this report is moderate because it is based on a well-implemented nonexperimental design. This means we are somewhat confident that the estimated effects are attributable to MSHA inspection violations, but other factors might also have contributed.

Features of the Study

The author used statistical models to predict whether a non-fatal or severe disabling injury would occur in the 12 months following a Mine Safety and Health Administration (MSHA) inspection violation. The study included 310 active underground coal mines in the United States. The author used publicly available MSHA Part 50 data files including the Accident Injuries and Inspections Data Set, the Violations Data Set, and the Mine Information Data Set. The data sets contained information on all injuries, accidents, scheduled and unscheduled inspections, air samples, and recorded violations for the coal mines between 2000 and 2014. The statistical models included mine characteristics (state where the mine is located, number of employees, shift length in hours, average height of the mine, miles from the nearest MSHA office, and number of mining days per week), injured miner characteristics (average months of experience in the mining industry, average months of experience at the mine, and average months of experience at the particular job), and violation variables (total number of violations and total financial penalties for the previous year). The author used rate of total lost work time as measured in days per 100,000 worker-days of operational effort as the outcome.

Findings

Health and safety

  • The study found that the rate of lost-time injuries could be significantly predicted by total worker time at the mine. As the number of worker days at the mine increased, the likelihood of lost-time injuries decreased.
  • The study also found that the rate of lost-time injuries could be significantly predicted by the average penalty assessed by MSHA, with a lower likelihood of lost-time injuries with higher penalties per violation.

Considerations for Interpreting the Findings

The author selected rate of total lost work time as the outcome to evaluate safety-critical incidents; however, it is not the only possible outcome that could be evaluated. Fatality rates are the most important measure regarding mine safety, but as the author notes, the rarity of mine fatalities would be problematic for statistical inference.

Causal Evidence Rating

The quality of causal evidence presented in this report is moderate because it is based on a well-implemented nonexperimental design. This means we are somewhat confident that the estimated effects are attributable to MSHA inspection violations, but other factors might also have contributed.

Reviewed by CLEAR

August 2020