Detailed in the report released on Friday by the Queensland government, there were 18 recommendations made to the broader underground coal sector from the exercise held between midnight and 5.30am on October 19.

There were a few relating to operations in the communications room during emergency conditions while other recommendations involved Incident Control Team matters.

But the unexpected issues with opening CSE SR 100 self-contained self-rescuer units notably caused a particularly “unnerving” experience for one miner in the exercise.

“The three assessors observed that two of the five units were stuck in their canisters and required forceful removal by hitting them on the ground and using screwdrivers to pry them free,” the government report stated.

“Difficulty taking units out of the canister is mentioned in the training videos for the CSE 100 self-rescuer. This is not surprising, considering the need for an airtight seal in a belt worn unit with a shelf life of 10 years.”

The month following the exercise, the US National Institute for Occupational Safety and Health released a safety alert on this product issue, with end covers found to be extremely difficult to remove from units manufactured between October and December 2008.

The Queensland assessors were also disappointed the difficulties with the canisters were not video recorded to help raise more awareness, as a “suitably configured gas detector” was not available to accompany the camera.

“In this year’s exercise, the problem did not appear to be with lack of training, but rather with a unit that is difficult to open,” the report noted.

“More work needs to be done to develop a self-rescuer that is fit for purpose, or other strategies must be adopted to control this risk.”

The scenario and the response

The emergency scenario designed for Carborough Downs took advantage of several site features, including a portal that was in a remote location to the pit top.

The dip of the target seam also provided a greater risk of runaway vehicles while the thickness of this seam and height of extraction, which leaves a 2-metre coal floor or roof, was deemed to have potential to create a ventilation furnace.

“This can reverse the ventilation, as happened in a fire at Appin colliery in 1976.”

While the scenario started with an LHD crashing into the “Big Harry” transformer, there were several other surprises.

The LHD operator struggled with severe burns and a broken leg as the resulting fire churned out carbon monoxide.

Inconveniently, a severe storm caused a failure of the main ventilation fans by interrupting electrical power to the mine and torrents of water entered the mine’s box cuts and underground workings.

Without a controlled ventilation system, the fire reversed mine ventilation, blocking off the main drift and areas of the primary escapeway with thick smoke, just leaving the belt conveyor roadway as an escapeway for trapped miners.

Another two hours into the scenario, the fire has damaged the gas-monitoring system at the mine along with telephone and other communications systems, including from the surface to underground.

About 50 miners were required to evacuate at this time.

The last twist involved a deputy who was undertaking outbye inspections at the time of the emergency, who is discovered to be missing when he fails to return from an inspection in a remote location of the mine.

As part of the response the assessors found that only one of the evacuating crews looked for the fire, at early stages when it could have been possible to extinguish it.

Other crews decided to escape by foot through the belt drift as soon as they found smoke.

The crew which fought the fire was noted to have used an adequate fire-fighting technique, but did so without breathing apparatus and did not have access to low expansion foam to help their efforts.

No stretcher was near the LHD operator with the broken leg, who was left alone while additional resources were acquired.

The observers were also surprised that more miners did not use vehicles to aid their escape when their initial indications were of low levels of carbon monoxide and no smoke.

“Almost all involved in the exercise appeared to associate using a self-rescuer with walking out,” the report cited.

Issues found with Incident Control Team matters covered the approach to fatigue management, identifying the number of miners underground, and the delegation of tasks as the scenario threw up more challenges.

Mines Rescue participation

The requirements involving Mines Rescue personnel did not meet expectations and resulted in recommendation six of the report: “That the Queensland Mines Rescue Service examines how it would respond if the mine indicates that ‘there may be a problem’.”

Four QMRS members from the mine were onsite by 4am, while the QMRS operations managers were in the office complex by 5.15am, unhelped by a 15-minute delay at the security gate.

There also appears to have been a communication error which resulted in a lack of participation from rescue teams from other mines.

“It is not clear who made the decision to turn the teams around,” the report said.

“Mines Rescue said that it was decided by the mine. There is no record of this in the mine’s logs or from discussions with those most likely to have been involved.

“Mines Rescue team members from other mines have expressed disappointment that they were not mobilised.

“Opportunities were lost to observe the process and time taken for team members to pass through the gate. It was also unfortunate that the decision-making process for rescue teams to enter the mine to deal with a large fire and a missing person could not be monitored.”

The Queensland government aims to take steps to prevent a repeat of discussed “shortcomings” with these matters in the hosting of future exercises.

While emergency exercise scenarios are designed to be very challenging, the mine was noted to have performed strongly with its ventilation monitoring and the procedures followed with restoring power.