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Operation Blowdown (1963)

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Original classification rating: not rated. This clip chosen to be PG

Clip description

The aims of the Operation Blowdown test are set out and the troops clear a site in the Cape York rainforest for the location of the test team.

Curator’s notes

by Adrienne Parr

This clip is from the film’s opening titles. With oblique but unmistakeable reference to the growing tensions in South East Asia, the narration asks the question: 'What effect would a nuclear explosion have on a tropical rainforest?’ Operation Blowdown involved defence scientific teams from Australia, the UK, Canada and the US, and was designed to answer the question – at least in respect to tactical military operations. Approximately 1,000 testing and monitoring instruments were prepared and eventually set up at the Iron Range test site. Much of the equipment supplied by the US had previously been used in connection with the 1962 Project Plowshare atomic test in Nevada. Operation Blowdown’s remote Cape York location was accessed via Gordon Airstrip. Built by the US during the Second World War, the airstrip had continued to be maintained by the DCA (Department of Civil Aviation). Among the army personnel employed to service the operation were 200 soldiers from the Brisbane-based 24th Construction Squadron Royal Australian Engineers.

Teacher’s notes

provided by The Le@rning FederationEducation Services Australia

This clip shows aspects of Operation Blowdown, which involved the detonation of a 50-tonne conventional (non-nuclear) bomb, intended to simulate a nuclear explosion, in tropical rainforest in north Queensland. It includes footage of scientists from the Defence Standards Laboratories (DSL) conducting tests with equipment designed to monitor the operation, and a meeting at the Department of Defence in Canberra. Soldiers are shown surveying and clearing the site and setting up tents to accommodate the several hundred personnel involved in the operation. The clip is narrated and has a soundtrack of dramatic music.

Educational value points

  • In July 1963, the Australian Army and the DSL, in conjunction with the UK, Canada and the USA, conducted Operation Blowdown which involved the detonation of a huge conventional bomb to replicate the effects of a nuclear explosion on a tropical rainforest. The operation took place in the northern Cape York Peninsula in Queensland. Fifty tonnes of trinitrotoluene (TNT), sourced from obsolete munitions, were used in the explosion. The TNT was filled into special containers and mounted on a 42-m tower.
  • Scientists from the DSL developed advanced electronic equipment to measure the effects of the blast caused by Operation Blowdown. The equipment was used to monitor blast pressures, to examine the effects of a blast in a forest on military material and field fortifications, and to assess the hazards of flying objects (which ranged from splinters to whole trees). Data collected also enabled scientists to gauge what effect the destruction caused by a 10-kiloton tactical nuclear bomb detonated in a jungle might have on troop and vehicle movement.
  • The DSL in Maribyrnong was established by the Department of Defence in 1910 to carry out research to aid the defence industry through the testing and development of weapons, munitions and other defence items. During the Second World War, for example, it was involved in developing gas masks and other counter measures against gas attack. Originally called the Chemical Adviser’s Laboratory, the organisation had several name changes before it became the DSL in 1953.
  • Operation Blowdown may have been designed to test the feasibility of using nuclear weapons to clear the jungles of Vietnam, at a time when Australia, as an ally of the USA, was becoming increasingly involved in the Vietnam War. In 1962 the Australian Government sent 30 military advisers to Vietnam and in 1965 committed troops to the War. The perceived need to conduct an experiment such as Operation Blowdown suggests that in 1963 the Government may have been preparing for the possibility of an escalation of its involvement in the Vietnam War.
  • The film Operation Blowdown may have been intended as propaganda to convince the public of the need to strengthen Australia’s defences and to justify the testing of a bomb. The opening sequence of the film, with soldiers advancing silently towards an unseen foe followed by a plane landing to the accompaniment of heroic music, generates a sense of drama and immediate threat. In the absence of an actual foe, the film uses the language of propaganda to establish the forest as the enemy that 'conceals many secrets’ and resists 'civilisation’ with 'furtive aggressiveness’.
  • In 2001 New Scientist magazine claimed that declassified Australian Government documents indicated that an actual nuclear device was detonated in Operation Blowdown. According to New Scientist, a medal citation for an Australian sergeant involved in Operation Blowdown describes the explosion as 'an airburst nuclear device’. This claim has been denied by the Australian Government as well as personnel who took part in the operation.