During a field trip along the east arm of
Great Bear Lake in August 1900, James McIntosh Bell of the
Geological Survey of Canada noted evidences of
iron,
copper,
uranium and
cobalt in the vicinity of Echo Bay. Thirty years later, on May 16, 1930,
prospector Gilbert LaBine discovered high-grade
pitchblende and
silver at this site. His company was then known as
Eldorado Gold Mines Limited (later renamed
Eldorado Mining and Refining Limited). Eldorado started off as a
radium mine in 1932, extracting radium from pitchblende. Radium
ores were highly valued at the time because the price of radium
salts, used in
cancer treatment and then monopolized by
Belgium, was US$70,000 per gram. The first concentration plant was a big erection at the site by
Allis-Chalmers of Canada in 1933–1934, with a radium
refinery built at
Port Hope, Ontario. Concentrates and cobbed material were shipped by barge and
airplane to rail head at
Fort McMurray,
Alberta, then by train to Port Hope. In 1940 the mine closed because of the expansion of European markets for radium. In 1939, at the beginning of
World War II, ore from Eldorado had been used in the first
chain reaction experiments, and as soon as the scientists had found out that these ores contained a rich store of
uranium oxide and were useful as a source of
nuclear energy. Gilbert LaBine's company was able to secure a contract with the United States military early in 1942. The Eldorado Mine at Port Radium was secretly
expropriated and transferred to the
Canadian Government in 1943-1944 and renamed Eldorado Mining and Refining Limited. Uranium ore from the mine was used in the
atomic bomb developments of 1945. Uranium mining continued after World War II. The mine was expensive to operate and grade of the ore was declining, so new technology was brought in to make the isolated mine profitable. The discarded
tailings were dredged from the bay when new machinery was installed to recover the uranium content. The underground workings were deepened and the
crown corporation sought out additional deposits of uranium across Canada. But in 1960 the original Eldorado Mine was exhausted and closed. In 1975 the Eldorado Mine was
dewatered by
Echo Bay Mines Limited to recover old silver and copper minerals. All activity ceased in 1982 and Eldorado Mine and the Port Radium settlement was burned and demolished. In 1984 the site was decommissioned as per local standards at the time. In 2006 an agreement was made with the local Deline community about remediation activities, which were completed in 2007. On 31 December 2016, the Canadian Nuclear Safety Commission issued a 10-year license (therefore running until 31 December 2026) to
Crown-Indigenous Relations and Northern Affairs Canada permitting long term monitoring and maintenance of the site. The mine is inspected by the Canadian Nuclear Safety Commission once every three years. The COVID-19 pandemic delayed the 2020 inspection until February 2022. ==Geology==