When graded roads were built for the Giles Weather Station (part of the Weapons Research Establishment) during 1952–1955, officials learned that Aboriginal people - probably then around 150 - lived west of the sites. Scouting just east of this area to find suitable locations for radiation sensors that would measure the fallout, Len Beadell records stumbling on an "Aboriginal Stonehenge", a geometrical pattern of upturned shale slabs extending for a distance of . An officer, the expert bushman Walter MacDougall was sent to warn them of the impending tests. A total of nine small hydrogen bombs ranging up to 25 kilotons were tested at Emu Junction (2 tests, 1953) and Maralinga (7 tests, 1956–1957). Given that only one officer and an assistant were assigned to warn the Spinifex people who lived across an enormous area far to the west of the test sites, many of the Spinifex were never informed, nor did they leave the area. Officially, all were forced to leave their lands and were not allowed within 200 km of ground zero. Officials made a leaflet drop, but the Spinifex could not read the leaflets and were wary and afraid of the aircraft.