Background
Underground mine workers need access to a safe place of refuge in the event of an irrespirable atmosphere. Refuge chambers provide a safe haven to support life, with a supply of breathable air that must be ready for use at all times.
The basic life-support features of a refuge chamber include:
- reliable and clean compressed air supplies
- the capability to totally seal workers from an external irrespirable atmosphere
- a cooling system to prevent heat-related disorders over an extended period of use
- an effective chemical scrubber system(s) to remove expired contaminants (e.g. carbon monoxide, carbon dioxide).
- reliable power or battery supplies.
The department's guideline on refuge chambers in underground mines recommends each refuge chamber have a design operating capacity of no less than 36 hours for occupants when operating as a stand-alone unit. Any refuge chamber not capable of sustaining life for this duration should not be used for emergencies (as defined by r. 4.36, Mines Safety and Inspection Regulations 1995), unless a risk assessment has confirmed its adequacy.
The department have concerns that the capacity for some refuge chambers to support life in an emergency may have been compromised.
Summary of hazard
A compromised refuge chamber may lead to the following issues during an emergency:
- inability to support life for the recommended minimum duration of 36 hours
- ingress of contaminants into the refuge chamber
- failure of life support systems to operate effectively (e.g. contaminant gases, heat)
- reduced battery power capacity.
Contributory factors
A poor understanding of the critical life support system components in a refuge chamber may decrease awareness of the factors that can affect the chamber’s performance and operational time.