Safety alert: Response times of gas detectors

A deputy’s gas detector alarmed at 2% methane in an underground roadway at a coal mine. He retreated from the roadway with his gas detector peaking at 3.5%. The deputy had entered a methane concentration greater than 2% without being aware. This was because of the inability of the gas detection instrument to instantaneously measure the actual concentration of methane in this situation. This incident occurred on 5 September 2017.

Recommendations

Mine operators should:

• Identify the response times for gas detectors in use at their mine.
• Review the operational risk assessments relating to the use of gas detectors at the mine to ensure that actions and protocols associated with gas detection are appropriate for the response times of the gas detectors and the environmental conditions that may be encountered. In addition to gas detectors used by deputies undertaking inspections, this review should consider operating speeds of vehicles and the distances travelled by those vehicles if gas is detected.
• Update the mine’s safety management system, as required by the above reviews.
• Ensure all personnel who are required to carry a gas detector are trained in the requirements of the mine’s safety management system relating to their duties, and are aware of the time lag response of gas detectors in use at the mine.
• Refer to SA10-04 Portable gas monitors for additional information relating to response times of gas detectors.

Download the full safety alert Response times of gas detectors.