Background
Underground mining operations are required to have an alarm system to warn personnel working underground when an emergency is declared. Normally this requirement is fulfilled by the use of stench gas, which contains mercaptans that act as an odourant and may be classified as a flammable gas. The stench gas is introduced into the underground workings from activation stations installed on the surface near mine openings (e.g. portals, shafts, rises) and also from underground locations.
This bulletin clarifies the interpretation of stench gas activation stations in relation to Regulation 4.37 of the Mines Safety Inspection Regulations 1995 (MSIR), which requires the manager of an underground mine to ensure that flammable liquids, flammable materials or explosives are not stored within 50 metres of any entrance to the mine. Desirable features and practices associated with stench gas activation stations are also outlined.
Stench gas activation stations comprised of connected cylinders are regarded as an installation rather than storage of flammable materials. Hence MSIR Regulation 4.37 and the associated 50 metre exclusion zone, is not applicable to such installations. However, cylinders of stench gas not connected to the installation must not be stored within 50 metres of a mine entrance.
Importantly, stench gas activation stations need to be carefully located, constructed and maintained to optimise their effectiveness and reliability as an alarm system and to ensure personnel are not exposed to hazards.
Summary of hazard
Improperly located and installed stench gas activation stations:
- may not perform effectively as an alarm system
- may expose persons working near them to hazards (e.g. mobile equipment, falling objects, slips and trips).
Contributory factors
There is a need to clarify the requirements of MSIR Regulation 4.37 and to reinforce good standards for stench gas activation stations.