Report - METEX - exposure to irrespirable atmospheres - November 2024 to March 2026

This report provides the findings of an assessment program at underground metalliferous mines focussing on the ventilation control plan

Sector	Metalliferous - underground
Principal control plan	Ventilation control plan
Material unwanted event	Exposure to irrespirable atmospheres
Topic	Exposure to irrespirable atmospheres

Operation type assessed

Operation type	Number of mines assessed
Underground	12
Total	12

Criteria assessed

Critical control	Criteria
Mine design to manage contaminant generation and/or interaction with contaminants to within safe limits	Has the mine executed their design to minimise generation and interaction with irrespirable conditions, including: Blasting to design Underground areas executed to design Ventilation (type, volume and layout) executed to design
Workers restricted / removed from areas with irrespirable atmospheres	Are personnel aware of the techniques to restrict or remove personnel from areas with irrespirable atmospheres, including: Blast exclusion zones Underground exclusion zones Application of remote mining Ventilation control devices TARPs for the withdrawal of personnel Is there evidence these are being implemented effectively on site?
Ventilation flow rates controlled to remove or minimise contaminants	Verify ventilation flowrates throughout the mine. Does it match the designed flowrates?
Pre-drainage and gas drainage (irrespirable gas reduction)	Is gas drainage being conducted as per design?

Findings with issues identified - underground

Critical control	Findings of concern	Findings of contravention	Findings of immediate risk	Total findings with issues
Mine design to manage contaminant generation and/or interaction with contaminants to within safe limits	1	3	-	4
Workers restricted / removed from areas with irrespirable atmospheres	6	5	1	12
Ventilation flow rates controlled to remove or minimise contaminants	1	4	-	5
Pre-drainage and gas drainage (irrespirable gas reduction)	-	-	-	-
Total findings with issues	8	12	1	21

Compliance notice type issues during the program

Notice type	Notices	Percentage of notices issued
WHS(MPS)A s23 notice of concerns	10	34%
WHSA s191 improvement notice	17	59%
WHSA s195 prohibition notice	2	7%
Total	29	100%

Total of 29 compliance notices issued to 11 mines.

Note: This data represents all notices issued during the program and may include notices other than ventilation control plan topics.

Recommendations

Operators of underground metalliferous mines should review their site principal ventilation control plan and the findings of critical controls assessed by the Regulator for the topic of exposure to irrespirable atmospheres:

Assessed critical controls	Recommendations to mine operators
Mine design to manage contaminant generation and/or interaction with contaminants to within safe limits	Gas monitoring equipment must be maintained and tested to meet with operational design parameters Worker re-entry times must be designed and monitored for compliance with safe exposure limits for noxious gasses Ventilation design to determine the maximum number of diesel powered vehicles permitted to operate within a specified ventilation zone Ventilation plans must be maintained and available to workers in an up-to date and fit for purpose state
Workers restricted / removed from areas with irrespirable atmospheres	Supervisors must ensure testing of atmospheres is under-taken before workers enter previously unventilated parts of the mine. In particular, after blasting operations and occasions when the local area ventilation fan was not operating Ensure adequate warning signage is provided at entry to sumps and dead-end roadways to restrict worker access and provide information about the state of ventilation inbye the sign
Ventilation flow rates controlled to remove or minimise contaminants	Ensure adequate and up to date ventilation status information is readily accessible to all supervisors responsible for inspecting and controlling ventilation in areas of the mine Ensure signage is located at all ventilation control devices to advise workers that only authorised persons are permitted to adjust air quantities passing through the device Ensure ventilation quantities are maintained to design at truck loading tip heads and bogging locations to minimise air contaminants Ensure corrective action reporting is provided in shift reports for any repair or replacement of damaged ventilation sheets and ventilation tubes affecting air flow to work areas
Pre-drainage and gas drainage (irrespirable gas reduction)	Consider potential for worker exposure to noxious gasses emitted into active work areas whilst drilling probe holes into old workings