On 14 September 1957, the British nuclear tests at Maralinga entered their second phase as Operation Antler began. These were the last British tests on mainland Australia.
British nuclear tests at Maralinga were conducted between 1956 and 1963 at the Maralinga site, part of the Woomera Prohibited Area in South Australia about 800 kilometres (500 mi) north west of Adelaide. A total of seven nuclear tests were performed, with approximate yields ranging from 1 to 27 kilotons of TNT (4 to 100 TJ).
Two major test series were conducted at the Maralinga site: Operation Buffalo in 1956 and Operation Antler the following year.
Operation Buffalo consisted of four tests; One Tree (12.9 kilotons of TNT (54 TJ)) and Breakaway (10.8 kilotons of TNT (45 TJ)) were detonated on towers, Marcoo (1.4 kilotons of TNT (5.9 TJ)) at ground level, and the Kite (2.9 kilotons of TNT (12 TJ)) was released by a Royal Air Force (RAF) Vickers Valiant bomber from a height of 11,000 metres (35,000 ft). This was the first drop of a British nuclear weapon from an aircraft.
Operation Buffalo was followed by Operation Antler in 1957, which tested new, light-weight nuclear weapons. Three tests were conducted in this series: Tadje (0.93 kilotons of TNT (3.9 TJ), Biak 5.67 kilotons of TNT (23.7 TJ) and Taranak 26.6 kilotons of TNT (111 TJ).
The first two were conducted from towers, while the last was suspended from balloons. Tadje used cobalt pellets as a tracer for determining yield, resulting in rumours that Britain was developing a cobalt bomb. Between 1956 and 1963, the Maralinga site was also used for minor trials, tests of nuclear weapons components not involving nuclear explosions.
Kittens were trials of neutron initiators; Rats and Tims measured how the fissile core of a nuclear weapon was compressed by the high explosive shock wave; and Vixens investigated the effects of fire or non-nuclear explosions on atomic weapons. Ultimately, the minor trials generated more contamination than the major tests.
The site was left contaminated with radioactive waste, and an initial clean up was attempted in 1967. The McClelland Royal Commission, an examination of the effects of the minor trials and major tests, delivered its report in 1985, and found that significant radiation hazards still existed at many of the Maralinga sites. It recommended another clean up, which was completed in 2000 at a cost of AUD $108 million (equivalent to $171 million in 2018).
Debate continued over the safety of the site and the long-term health effects on the traditional Aboriginal custodians of the land and former personnel. In 1994, the Australian Government paid compensation amounting to $13.5 million (equivalent to $23.7 million in 2018) to the traditional owners, the Maralinga Tjarutja people. The last part of the land remaining in the Woomera Prohibited Area was returned to free access in 2014.
By the late 1970s there was a marked change in how the Australian media covered the British nuclear tests. Some journalists investigated the subject and political scrutiny became more intense. Journalist Brian Toohey ran a series of stories in the Australian Financial Review in October 1978, based in part on a leaked Cabinet submission.
In June 1993, New Scientist journalist Ian Anderson wrote an article titled “Britain’s dirty deeds at Maralinga” and several related articles. In 2007, Maralinga: Australia’s Nuclear Waste Cover-up by Alan Parkinson documented the unsuccessful clean-up at Maralinga. Popular songs about the Maralinga story have been written by Paul Kelly, Midnight Oil and Anderson Bruford Wakeman Howe.