The explosion at Woomera Range created a visible pressure bubble in the atmosphere, seen in this oblique photo. Photo by 92 Wing Photographic

By Darryl Johnston
ALL eyes were fixed on a tiny speck in the horizon shimmering in the desert heat outside Woomera. Two guideposts protruding from the sand pointed toward the object.

At four minutes to detonation Minister for Defence Robert Hill gave the all-clear by hand-held radio to the men positioned in an underground control and firing bunker 800m from Ground Zero.

More than 150 people had travelled to the South Australian outback to witness the blast.

They included Army and Air Force personnel, Defence and industry representatives from the UK, Singapore, the Netherlands and Norway, and observers from Malaysia, Germany and the United Arab Emirates. Representatives from Australian Defence-related industries and Woomera residents joined them.

The large crowd stood at an observation point a safe 6km from Ground Zero. Spectators began jostling for prime locations to witness the impending blast, cameras were fixed into position and everyone waited in an atmosphere of anticipation.

An RAAF aircraft with a film crew on board flew overhead toward ground zero then a muffled countdown came over the speaker: “Five ... four ...three ...two ...one.”

Out of the desert came a bright flash. Red earth heaved into the sky. A huge black cloud formed and grew bigger and bigger. As it rose into the cloudless sky it took on the shape of a giant mushroom.

The soundwave hit 12 seconds later, a loud and low rumble that caught many by surprise. It was greeted with cheers from the crowd.

After more than two years of detailed planning, the 27-tonne Woomera Explosives Trial was over in a matter of seconds.

All that was left at Ground Zero was a giant pile of rubble at the bottom of a huge crater and a large black cloud that gradually dispersed as it drifted to the southeast. Behind the scenes valuable data had been collected that will put to good use in the future.

The site had been extensively instrumented with multiple sensors to measure blast pressure.

The information was relayed by 10km of fibre-optic cable and 35km of data cable laid underground like a giant spider web.

Thirty cameras in protective housings recorded the explosion. The effect of the blast on five fixed domestic structures was also recorded.

The massive explosion resulted from the simultaneous detonation of 1620 8-inch howitzer shells. They were housed in a purpose-built explosive storage house.

The purpose of the trial was to obtain data from which safety criteria for explosive storage and handling can be determined and modelled; including whether NATO-mandated buffer zones around stored explosives should be adjusted.

Army specialists from the Directorate of Trials within DSTO planned and managed the trial. The UK’s Defence Ordnance Safety Group sponsored it. The explosion was the latest in a series of huge static storage blasts conducted under a memorandum of understanding for

Defence research between the UK Ministry of Defence and the Australian Department of Defence.

The Netherlands, Norway and Singapore also participated in the trial. The last trial took place in 1999 and involved 40 tonnes of high explosives.

Another blast took place on October 7 to determine the effects of a detonation of five tonnes of high explosives in field storage conditions.

It gathered data for safety criteria for explosive storage when armed forces are deployed on operations, particularly peacekeeping deployments.

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