At 8pm on Monday July 30 the mine's crews were alerted to a simulated frictional ignition on the longwall face that sparked a gas explosion that had damaged a ventilation control and created an irrespirable atmosphere.
As the night progressed the workers, already under pressure in the exercise, learned that equipment had been damaged in the incident, crew members were injured and required treatment, and man-riding at the No. 1 shaft was temporarily inoperable.
In a detailed report on the incident, assessors from the Queensland Department of Mines and Energy's Simtars, Queensland Mines Rescue Service, the CFMEU and the Minerals Industry Safety and Heath Centre said that while the crews generally responded well in the drill there were noticeable shortfalls in some procedures.
The assessors commended the mine on its implementation of the Mine Emergency Management Systems [MEMS], said the use of non-verbal communication in the exercise was strong enough to allow successful communications between the workers, and the use of vehicles to escape speeded the evacuation process.
Points of concern raised in the mine's exercise, however, included a delay in the deployment of mines rescue; a lack of clarity in the site's emergency response plan duty cards; and the mine's supervisory control and data acquisition (SCADA) system, which proved to complicate the reading of gas levels because it had many other types of alarms attached to it.
In terms of equipment and the mine's rescue facilities, the exercise revealed some of the mine's crews had issues with donning and changeovers of self-contained self-rescuers (SCSRs); compressed air breathing apparatus (CABA) was introduced into the mine but there was no obvious training into its use; and the mine's rescue station lacked equipment and was not clearly identified.
Accessing emergency personnel also proved to be an issue during the drill, with the on-duty mines inspector not attending the drill due to a misunderstanding; the industry health and safety representative not attending the drill; and the site safety and health representative not notified of the exercise.
Rather than the exercise being a pass or fail test for Grasstree, the assessors said it takes a look at the industry as a whole and identifies ongoing weaknesses in mines' emergency response procedures. It is aimed at improving emergency response procedures across the entire industry based on the findings at the mine where the exercise was run.
In its final recommendations to Grasstree's management the report included:
- A review into the mine's emergency response management plan, associated duties, duty cards and forms;
- Training in donning and changeover of SCSRs for all underground personnel;
- Training in use of CABA by underground personnel;
- Review of the layout of changeover bays to reduce congestion at entrance;
- Put in place a more structured and better resourced people control mechanism for the crews when they exit the mine;
- Consider a system for effective transport of persons from Grasstree West to Grasstree and initiate a series of works to ensure the main escape way between the areas is trafficable;
- Improve the SCADA alarm system to flag the Trigger Action Response Plan (TARP) involved;
- Make a readily available list of emergency personnel contacts and consider the use of speed dial for this list;
- Improve facilities in the operations room to include electronic access to forms and mine plans; and
- Review the debrief process to ensure relevant information is delivered to the incident management team.
On an industry level the assessors said all mines should pay attention to the issues revealed in the exercise, including:
- Continued focus on the training of personnel in the donning and changeover of SCSRs;
- Training in the use of changeover bays for underground personnel;
- Mine workers must be trained and demonstrate competency in their mine's evacuation protocols;
- All mines should modify their emergency contact list to contact the Mines Inspectorate via 07 3237 1696, the emergency number;
- All mine management plans, hazard management plans and associated duty cards and forms should be revised;
- Need to establish a standard cross-industry non-verbal communication practice to assist in developing common knowledge across the transient mining workforce;
- Investigate easy and readily available methods to transfer data in an emergency;
- Look at text messaging options for underground phones;
- All mines to ensure they have adequate emergency phone coverage onsite and consider installing a mobile phone repeater dish onsite if required;
- Where mines have CABA deployed all underground personnel must be sufficiently trained; and
- Minesites need a streamlined entry point to record all personnel entering the site in the event of an emergency.
The next Level 1 exercise will be held at Newlands mine next year; however, as always, the timing of the exercise will be a closely guarded secret.