Cape York PeninsulaEFFINCUEfar north Queensland


A significant anniversary passed quietly back in July this year – it was 50 years since the Australian Government blew up a significant chunk of far north Queensland. July 18, 1963 was the day a very big bomb brought the Cold War to a very hot part part of the world. It was called Operation Blowdown.

The Government of Prime Minister Robert Menzies had been moved to wonder what the effect of a nuclear explosion would be on a tropical rainforest. Defence scientists from Australia, the UK, US & Canada were engaged to find the answer. This was at the height of the Cold War, when you didn’t need the gift of prophecy to see conflict looming in South-East Asia. Our Government fully expected Australia would be involved and imagined nuclear weapons might be used. What would be the effect on a tropical environment?

The scientists gathered at Iron Range, near the modern day indigenous community of Lockhart River, on eastern Cape York Peninsula. In a highly classified operation, they set up over one thousand instruments to measure an explosion, and dozens of film and stills cameras to capture it. Thankfully, the Government was “reluctant” to use a real nuclear bomb, and instead decided to simulate the destructive power by using what was later reported as a device made with 50 tons of TNT, perched atop a 140 foot tower.

About 17,000 trees had been catalogued, with individual species tested to establish mechanical strength. Four lanes of instrumentation were placed at right angles, intersecting at the site of the tower. A 60-metre wide lane was cleared of all vegetation except for a few large trees at varying distances from ground zero. Military structures, equipment and dummies to simulate troops were placed to replicate operational conditions.

At 8.30am on Thursday 18 July 1963, someone pushed the button and the device exploded. It made a hell of a mess of what was pristine FNQ bushland. Watch the newsreel footage of preparations and the explosion here


The data and images yielded what Defence sources called valuable information about how such a huge blast would affect military material, field fortifications, supply points and foot and vehicle access. The Cold War warriors were no doubt well pleased with the results. But Operation Blowdown had at least one unintended consequence. It became something of a rallying point for environmentalists, this in an age before the very vocal and well organised Green groups that began to form later in the 60s. When news of the explosion got out late in 1963, Alec Chisholm wondered in the Sydney Morning Herald how much damage had been done to flora and fauna in an area renowned for a diversity of plant and bird life.

And there was another chapter in this story just a few years ago. It seems there may have been a secret US military plan to use much the same area to test deadly Sarin gas during the 60s.Details emerged in declassified Australian Defence Department files of a plan to bomb and spray Australian servicemen with the nerve gas. It’s understood that plan never went ahead. Read that story here

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    1. I’d seen a commemorative sign at Lockhart River a couple of years ago but hadn’t really heard the story until now. It’s an amazing tale. The old newsreel is priceless.

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