Workers in heavy machinery at a Bowen Basin coal mine can continue to work during lightning strikes after the Industrial Court ordered stays be maintained on two directives from Resources, Safety and Health Queensland.
BM Alliance Coal Operations Pty Ltd (BM), which operates the Peak Downs mine near Moranbah, appealed the directives which were issued by Jacques le Roux, Chief Inspector of Coal Mines, following concerns about the use of Heavy Mobile Equipment (HME) during violent electrical storms at the site.
In a 34-page decision delivered on Wednesday, President Davis ordered the stays be maintained and the parties serve submissions on final orders.
The directives, issued under the Coal Mining Safety and Health Act 1999 (Qld) in October last year, related to BM’s Severe Weather Policy and associated Trigger Action Response Plan (TARP). These prescribe actions to be taken in the event of lightning, and operate around triggers identified as levels.
Level 1 is activated when lightning is within 60 to 30km of mine, Level 2 when it is within 30 to 16km, and Level 3 when it is less than 16km from mine.
The TARP allows certain HME to continue operating in level 3 conditions.
Mr Le Roux directed that work by certain HMEs should stop at level 2 conditions, saying the risk of injury to a person may reach an unacceptable level.
BM appealed the directive, arguing the HMEs operated as perfect “Faraday cages” in the event they were struck by lightning.
President Davis identified two concerns about HME management during lightning.
“The first is the prospect of the HME being struck by lightning and some of that electrical charge passing into a person within the vehicle,” he said.
“Secondly, it is common ground that a HME operating on air-filled rubber tyres is in danger if struck by lightning, as the tyres are vulnerable to explosion, leading to a loss of control of the vehicle.
“The answer to this problem is to fill the tyres with nitrogen rather than air which contains oxygen. This avoids the tyres exploding.”
One directive required any HME with rubber tyres to immediately stop work at a level 2 alert, where BM had allowed HMEs with tyres filled with purity of 95 per cent nitrogen or more to continue to operate through both a level 2 and level 3 alert.
In December last year, the court refused BM’s application for a stay of the directive. Last month, BM filed a further application for stay, and orders were made by consent for the directive to apply to level 3 conditions but not level 2, pending the making of final orders.
President Davis said the Act described an acceptable level of risk as being “within acceptable limits” and “as low as reasonably achievable”.
“Those two considerations are quite different,” he said.
“Some operations may be such that whatever safety measures are taken, the risk cannot be brought ‘within acceptable limits’ and therefore operations must cease.
“Mr le Roux considers that operating HMEs at Level 3 conditions is such an example. BM says that operating HMEs at Level 3 conditions is within acceptable limits of risk, provided that the tyres are filled with nitrogen.
“If that is so then the question becomes, by reference to all precautions taken, whether ‘the risk is as low as reasonably achievable’.”
He said it was common ground that HMEs could be struck by lightning when they were operating in coal mines in the Bowen Basin.
“It is also common ground that as a matter of physics, a metal vessel (such as a truck), when struck by lightning, operates (not necessarily perfectly) as a Faraday cage so that lightning which hits the HME will tend not to pass into and through the occupant of the vehicle but will pass across the metal surfaces of the vehicle into the earth,” he said.
“It is common ground that if a truck suffers a lightning strike, there is a danger that air-filled tyres will explode as the electric current passes through them to earth. It is also common ground that nitrogen-filled tyres will not explode.”
President Davis said there were two questions related to each other:
(a) assuming the lightning strike on a HME may cause the tyres of the vehicle to explode, and thereby risk harm to the occupant, is the operation of those vehicles at Level 3 of the TARP an acceptable risk when the tyres are filled with nitrogen; and
(b) assuming that HMEs with rubber tyres may be struck by lightning but the tyres cannot explode, does the prospect of them operating at Level 3 of the TARP otherwise constitute an unacceptable risk to workers within the vehicle.
In ordering the parties to file submissions, President Davis said there were various possibilities to resolving the appeal, including varying the directives consistent with his reasons, having the issue returned to Mr le Roux, and amending the lightning TARP to deal with issues such as insulation within HMEs.
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