How Athabasca uranium deposits were discovered from the air
By Dr. Edward Schiller
Encompassing about 100,000 km2, the Athabasca Basin is a region in the Canadian Shield of northern Saskatchewan and, to a smaller extent, Alberta, Canada. It is best known as the world’s leading source of high-grade uranium and currently supplies about 20% of the world’s uranium. The basin is the home of both uranium producers and explorers which are covered elsewhere on the Resource World website.
Uranium in Saskatchewan was discovered in 1934 at Beaverlodge in the northwest corner of the province and produced uranium from underground mines from 1952 to 1982. Saskatchewan’s current status of being the world’s second largest producer of uranium started in the corporate offices of the Dynamic Group of oil companies on the second floor of the Fina building in 1966 in Calgary. *
The Group had an aircraft that they used to go fishing on Vancouver Island that was written off as a business expensive. Their accountants said this must change and you must find some kind of exploration activity to justify owning an aircraft.
Their geologist, Roy Jones, said that he had heard that aircraft equipped with an onboard Geiger counter can detect radioactivity from the air and was being used over the Colorado Plateau where several mines were in production.
The directors responded by agreeing to do the same thing in Canada. But where? Jones replied, In Saskatchewan there is a large sedimentary structure called the Athabasca Basin consisting of sandstone and related stratified rocks as the closest thing to the Colorado Plateau and located next door from Alberta in Saskatchewan and with Beaverlodge at Uranium City an added attraction.
Geophysical airborne surveys were an uncommon mineral exploration tool at that time. Airborne magnetic surveys were used to detect German submarines off the US coast during World War II but not commonly used in mineral exploration until years later.
Off to Saskatchewan the plane went equipped with a Geiger counter and flew a 27,200 line-kilometre survey at a 3.2-kilometre spacing and a 50-metre elevation at a cost of about $100,000 over the entire Athabasca Basin.
The Group received rebates from the Provincial Government through a Precambrian Incentive Program for their northern Saskatchewan program and radioactive anomalies they did find. As an oil company, they needed a knowledgeable partner and they consummated a joint venture agreement with the British American Oil Company which later became Gulf Oil Canada. Gulf optioned five Dynamic Group Exploration permits and proceeded to follow up on 34 high priority radioactive anomalies.
Drilling commenced in the summer of 1968 and anomalies on the west edge of Wollaston Lake led to the discovery of the Rabbit Lake deposit; the equally significant Key Lake, Cluff Lake and Midwest Lake high-grade deposits were later found by others. The result of the world class Rabbit Lake discovery led to the recognition of a unique deposit model to be called Unconformity-type and the Athabasca Basin was the locality of this type of deposit. High-grade pitchblende was found to be concentrated at the base of the sedimentary basin at the contact with the underlying basement rocks at the unconformity.
In 1968, once the rumours of the Gulf discovery was made known, the seven public companies of the Dynamic Group soared and a staking rush to acquire permits and claim blocks reached historic highs totalling some 120,000 km2 by over 50 companies only to be surpassed by the diamond discoveries staking rush at Contwoyto Lake in the Northwest Territories in 1991.
In the events that followed the Rabbit Lake discovery in 1970, the Saskatchewan Mining Development Corporation (SMDC) was formed to later merge with Eldorado Nuclear Ltd. in 1988 to form Cameco Corp., a public company. Cameco and partners discovered the McArthur River and Cigar Lake high-grade uranium deposits that went into production in 1999 and 2014, respectively, replacing the mined-out Key Lake, Cluff Lake and Midwest Lake mines. Currently, McArthur River and Cigar Lake are in a safe state of care maintenance with production suspended due to the prolonged weakness of the uranium market and risks posed by the COVID-19 pandemic.
*New Continental Oil Company, Mill City Oil Company, Royal Canadian Ventures Ltd., Consolidated East Crest Ltd., Dynalta Oil and Gas Ltd., Crusade Oil Company, Dynamic Oil Ltd., and a private company owned by certain principles of the above companies.