In a safety alert issued by Rob Regan, director of the Mine Safety Operations Branch under the Department of Industry and Investment, mines have been advised to identify and control risks.
The results of coal dust testing in the Newcastle region revealed that 44 out of 104 samples taken in longwall operations exceeded 10mg/cu.m – a failure rate of 42.3%.
Fifty of the 95 longwall samples in the Hunter region – which is more than half at 52.6% – failed the government limit.
None of the 29 longwall samples in the Western region failed while 25.3% of the samples in the Southern District exceeded the limit.
Non-longwall underground coal mines fared better with a total of 21.8% exceeding the limit for all regions.
Of the 426 surface samples taken at open cut coal operations and coal handling and preparation plants, 2.1% exceeded the state limit.
Examining the sampling reports, Regan outlined the following likely causes of high coal dust levels:
- Inadequate ventilation
- Inadequate water or dust control
- Poor operator positioning
- Damaged equipment
- Poor work practices.
He also suggested the following strategies to combat the problem:
- Isolation or capture of dust at source via sealing of transfer points, BSL, crushers
- Operating water sprays at appropriate locations and as near as possible to the point of breakage with sufficient water volumes, pressure and correct sizing of water jets/droplets
- Ventilation of the correct quantities and at the right location
- Advance ventilation ducting/brattice to mine ventilation standard
- Regular maintenance of dust suppression equipment
- Operator positioning, job rotation and automation
- Control of dust levels along travelling roads
- Respiratory protection by personal protective equipment.
Regan said site-specific safe work procedures needed to be developed in consultation with all relevant people.
“It is possible to hose down pipes, ventilation ducting or belt structure prior to removal and transport,” he said.
“If eliminating the risk is not possible then the remaining hierarchy of controls needs to be applied.
“This can include improved ventilation, dust suppression, maintaining equipment and closer supervision.
“Deputies are not immune from a failed result and are expected to lead by example and implement the control strategies for each activity. Finally, and not as a substitute for the other controls, personal protective equipment can be worn.”
The 10mg/cu.m limit on inhalable dust in coal operations was imposed in December 2007 from notice provided under the Coal Mine Health and Safety Act.
