Reliability of flammable gas detection methods in Japanese coal mines

Japanese mine safety legislation was enacted in 1949. Improvements in safety and production in the mining industry have been achieved to a large extent under this legislation. However, because of the prescriptive legislation style of mine safety regulations, the degree of safety achieved has not been evaluated from a system performance point of view. Articles of the coalmine safety regulations prescribe detailed technical requirements for coalmine safety. In comparison to performance-based legislation, the prescriptive regulations do not require risk assessment and management. There are few criteria to evaluate safety measures. An investigation of the reliability of the flammable gas measurement system at the Kushiro coalmine has been undertaken. The results demonstrate aspects of implementation of risk management concepts into Japanese mine safety regulations in 2005.