MBGS geologists undertook assignments relating to a wide range of minerals, particularly in the early years, when the company was seeking to establish a broad client base. In 1974, the exploration section of CRA needed some geological mapping done in the Proterozoic metamorphic strata (Corella Formation) around the Mary Kathleen Uranium Mine. The challenge was to study the sedimentary features of the metamorphic rocks and determine the stratigraphic position of the host of the uranium mineralisation (a cobble conglomerate).
John Bryan spent about ten weeks in the field carrying out the mapping, over an area of about 25 km2. Although the mine had operated from 1958 to 1963, producing 4,000 tonnes of Uranium Oxide (yellow cake), the reason for the location of the deposit was not well understood. This stratigraphic mapping was able to help resolve that and provide data that would assist with the location of other mineral deposits in this geological domain. During the initial five years of production, Mary Kathleen was Australia’s largest uranium producer with “yellow cake” going to the United Kingdom Atomic Energy Authority. The mine re-opened in 1976 after gaining approval to sell uranium oxide to Germany, Japan and the USA. The mine was closed in the 1990s and the town area and the mine was rehabilitated. When the mine was operating, the town had a population of about 1,000, and the facilities included a shop, an orchard, a lawn bowls club , supermarket , tennis courts , a medical centre, school, ambulance station and fire station. The adequate water supply helped maintain lots of gardens and lawns in the town and it was a great example of a mining community for those days.
In the 1980s MBGS’ Kerry Whitby and Kim Bayly ventured to South Australia to the Eucla Basin (just north of the Nullarbor Plain) to explore for low rank coals that exist in that sedimentary basin. The exploration area, held by Investigator Coal (CRA), was extremely remote, with access via the Nullabor Road to Yalata, then north across the Transcontinental rail line at Ooldea siding and further north to Maralinga. From Maralinga, a Suunto compass-bearing was all we had to direct a small dozer to push a “gunbarrel” track to our target amongst the sand dunes of the Great Victoria Desert, about 50 km to the west of Maralinga. Maralinga of course was where the atom bomb tests were carried out by the British in the 1950s – MBGS’ second “brush with Uranium”.
While passing through Maralinga, we took the opportunity to explore some of the remarkable bomb detonation sites, at which our downhole gamma logging equipment went furiously off-scale.
From the outskirts of the Maralinga village our bulldozed track to the drill sites negotiated around “hot spots” of buried radioactive waste and buried equipment such as bulldozers contaminated during the tests. There is a strong probability that the Uranium Yellow Cake from Mary Kathleen was used by the UK Atomic Energy Agency to make the atomic bombs that were tested at Maralinga.
Coal seams in the Eucla Basin were few and far between, so no coal mines eventuated, and the areas affected by the atomic tests have been substantially rehabilitated since our geologists were there. At the time of our working at Maralinga, the very long concrete airstrip, that was used by UK long range military aircraft, was still operational and could be used by light aircraft to access the site from Ceduna. We would order supplies through the Flying Doctor radio and it was delivered by the Port Augusta-Kalgoolie train each week to Ooldea. An interesting adventure into a remote, and at the time, little visited region of Australia.
