Self-Contained Self-Rescuer (SCSR) devices play a vital role in keeping underground miners safe in Australia.
These portable devices are designed to provide each individual miner with a short-term supply of oxygen in the event of an emergency.
However, the oxygen supply is finite, so the miners have to safely replace their SCSR units with a longer duration supply before it is exhausted.
Simulations of this changeover procedure have revealed how easy it is for workers to make a potentially fatal mistake.
The Queensland Government’s Safety in Mines Testing and Research Station (SIMTARS) has been working alongside the Australian Coal Association Research Program (ACARP) to report on methods that would guarantee a safe changeover process.
According to Darren Brady, the manager of the SIMTARS’ occupational hygiene, environment and chemistry centre, the SCSRs were developed to replace the old scrubber/filter rescuers that miners wore in the past.
“If an underground mining environment was depleted of oxygen for whatever reason, the scrubber/filter rescuers would not have been any help,” he told Australian Mining.
“These devices did not produce oxygen; all they did was filter out carbon monoxide.
“Currently, the SCSRs are worn on the belt of all underground coal miners and, depending on the activity, will provide around 20 minutes of oxygen.”
Brady said the mine operators are responsible for ensuring that the tunnels and shafts have adequate locations for the miners to changeover their SCSRs.
“The mine needs to ensure the longer duration units are strategically located in changeover stations where the miners can reach them,” he said.
“These stations should also preferably be in a safe environment and ideally the mine will have one at each SCSR supply point.”
According to Brady, the Queensland Government runs an annual exercise simulating a large scale mine emergency.
“We have found, time after time, whenever a crew needs to changeover their SCSRs, some of them will get it wrong,” he said.
“A whole variety of things could happen; the miner might take a breath, put the new device on incorrectly or do something simple like forget to put a nose clip on.
“If the workers get it wrong in the simulation, chances are they will get it wrong in a real event.”
In some of the past simulations, the safety inspectors sprayed things like orange essence into the air during the changeover period.
“If any personnel could smell or taste the essence, it meant they were exposed to the environment,” Brady said.
“So had they been changing over in a toxic atmosphere, they could be dead.”
Some mines also use an ‘air shower,’ or a compressed air outlet, as part of their changeover stations.
According to Brady, the miners are supposed to stand under the outlet and change their apparatus in supposedly clean air.
“Our modelling has shown that this compressed air zone was actually very small, so it may be giving a false sense of security,” he said.
Brady believes the problem has been exacerbated by the fact that many mines rely on training and technique alone.
“We are not trying to take away from training and it will always be needed,” he said.
“But, we have seen that it does not always work on its own.”
In order to develop a safe solution to the issue, the SIMTARS research team examined the range of SCSR and changeover station technology available on the market.
“We were looking for an affordable option that would guarantee that miners would not make a mistake during a changeover underground and if they did, it would not be fatal,” Brady said.
“We were trying to find something that already existed and could be easily implemented.
“We looked outside the mining industry to see what was available, but we did not really find anything suitable.”
As a result, the team decided to develop a prototype.
“We actually came up with a design for a personal changeover station,” Brady said.
“We are hoping our final report will encourage someone in the industry to take that prototype a bit further.
“It is more likely that a combination of different devices will probably be required.”
Brady envisages that the SCSRs will eventually be dock-able, meaning the miners would be able to replace the oxygen supply without having to remove any equipment and therefore expose themselves to the environment.
“That is probably the way of the future, but that is not going to happen in the next year or two,” he said.
“This is why we have been looking for something that is affordable and easy to implement alongside current units, but also guarantees safety.”
While Brady does not think the team’s final report will lead to changes to the safety legislation or training requirements, he hopes it will encourage the industry to take the problem seriously.
“I would like to see the industry recognise the need for this technology and push suppliers and manufacturers to take the next step,” he said.
The report will be tabled by SIMTARS and ACARP later in the year.