Hoidas Lake is a remote northern Canadian lake which lies approximately 50 kilometers north of Uranium City, Saskatchewan. Named in honor of Irvin Frank Hoidas, a Royal Canadian Air Force pilot officer killed in action during the Second World War when his Stirling W-7520 crashed near the Belgian town of Saint-Truiden, it is the site of Canada's most advanced rare earth element (REE) mining project.
The mineralogy of the Hoidas Lake rare earth deposit differs from most other such deposits in that it is hosted in veins of apatite and allanite. Hoidas Lake also differs from other deposits in that it contains a significant amount of heavy rare earth elements, such as dysprosium. This abundance of heavy REEs is significant, as there is a growing demand for the heavier rare earths in high-tech manufacturing (such as the use of dysprosium in the manufacturing of hybrid car components.)   Mineralization is presumably hydrothermal, from an alkali or carbonatitic source at depth.
Ongoing work at Hoidas Lake has delineated a vein system (known as the JAK zone), which extends for at least a kilometer along strike. The limits of the system have not been established along strike nor along dip, and the zone's total extension is therefore unknown. The resource zone averages 75 m in width and is composed of individual veins which, though ranging from one to eleven meters in thickness, average about three meters each. Veins are continuous to 300 m depth and follow an anastomosing geometry.
Estimates of the resource given current delineations and assuming a 1.5% total rare earth cutoff, have established a presence of at least 286,000 tonnes of rare earth ore, which is enough to supply more than 10% of the North American market for the foreseeable future.
- Irvin Frank Hoidas
- Hoidas Lake, Saskatchewan
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