The Eldorado Mining and Refining Limited company was originally organized in 1927 as Eldorado Gold Mines Limited to develop a gold mine in Manitoba. Its president Gilbert LaBine later found radioactive deposits at Great Bear Lake, Northwest Territories in 1930, which led to the development of the Eldorado Mine at Port Radium. They built a state-of-the-art refinery in Port Hope, Ontario in 1933.