Coroner tyre monitoring call sees pressure mount

By: Steve Skinner


The pressure is on for improved tyre pressure monitoring in the wake of a coroners inquiry, and there is no shortage of technology to choose from.

Coroner tyre monitoring call sees pressure mount
Potentially fatal: a zipper rupture in a tyre sidewall. Photo: US Rubber Manufacturers Association.

 

The death of a truck driver at a Queensland mine site has further increased the interest in improved safety when it comes to tyre pressures and the changing of tyres and wheels.

In 2010 road train driver Wayne MacDonald, 53, was killed at the Foxleigh coal mine in the Bowen Basin.

Last September Queensland coroner David O’Connell delivered his findings on the death of Mr Macdonald. The findings were not widely reported at the time.

The tragedy followed two other tyre blast deaths at Queensland mine sites (including the same one) a few years before.

Mr MacDonald was under a trailer and had released the bottle jack when he was hit by a "percussive shockwave of air" when a replacement tyre exploded as it came under load after contacting the ground.

The coroner found the tyre exploded due to a "zipper failure". It had previously had a puncture repaired, and was marked "SLOW LEAK/OK" with a line crossed through the "slow leak" part.

However an independent expert found no evidence that it was faulty before it was selected, pumped up in a cage and then fitted on the fatal occasion.

Running under-inflated can cause sidewall failure leading to zipper ruptures. But the coroner said it wasn’t possible to know if the replacement tyre had previously run under-inflated for 100 metres or 100 kilometres, or not at all; and that zipper ruptures can happen without warning.

(Bulges and undulations in the sidewall are just two of the giveaway warnings of a potential zipper rupture.)

Coroner O’Connell made recommendations specific to the mining industry, but there are several of them which have provided serious food for thought for the wider trucking industry. They are:

"That every tyre, whether new or repaired, undergo integrity testing by its inflation in a suitable tyre inflation cage, to a pressure of 120 per cent of the tyre’s recommended minimum cold operational inflation pressure, and then left for 20 minutes."

"That any jack used by an operator has a handle of sufficient length to allow the operator to safely use the jack without the operator being in, or under, the truck or trailer, or within close proximity of the vehicle’s tyres whilst jacking occurs.

"That the industry investigate, and implement within two years, remote, or wireless, tyre pressure sensing equipment to allow operators to monitor tyre pressures from within the cabin of the truck.

"That until remote or wireless tyre pressure sensing equipment is introduced for these mine site tyres that the practice of tyre tapping (with a metal bar) should not be continued, and that accurate, calibrated, pressure gauges should be used to check correct tyre inflation…"

Coroner O’Connell acknowledged that going around every tyre with a gauge could take a couple of hours for a road train. He said it’s time which could be saved by a central pressure monitoring system.

He said inquest evidence suggested a rough guide for the cost of a wireless system was $11,000 for a truck and three trailers, plus $3000 fitment.

"The evidence was that a single tyre is worth some $600, and if correct operational pressure is kept of a tyre, its service life will be longer and the $11,000 initial cost quickly recouped."

 

Check out the July issue of ATN for more on tyre pressure monitoring and inflation technology.

 

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