CAMECO CORP
For the period ended Dec 31, 2025. Filed Mar 19, 2026.
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The yearly report of certain Canadian companies, filed under a joint US and Canadian system. It is the main yearly account these companies give US investors, largely as filed in Canada.
FY2025 · Filed Mar 19, 2026
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Contents
EX-99.3 · Mining method
Mining method
At Cigar Lake, the permeable sandstone that overlays the deposit and basement rocks, contains large volumes of water at significant pressure. Before we begin mining, we freeze the ore zone and surrounding ground. We use a jet boring system to mine the ore.
Jet boring system (JBS) mining
As a result of the unique geological conditions at Cigar Lake, we are unable to utilize traditional mining methods that require access above the ore, which necessitated the development of anon-entry mining method specifically adapted for this deposit. After many years of test mining, we selected jet boring, and it has been used since mining began in 2014. This method involves:
| • | drilling a pilot hole into the frozen orebody, inserting a high-pressure water jet and cutting a cavity out of the frozen ore; |
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| • | collecting the ore and water mixture (slurry) from the cavity and pumping it to a storage sump, allowing it to settle; |
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| • | using a clamshell, transporting the ore from the storage sump to an underground grinding and processing circuit; |
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| • | once mining is complete, filling each cavity in the orebody with concrete; and |
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| • | starting the process again with the next cavity. |
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We have divided the orebody into production panels and at least three production panels need to be frozen at one time to achieve the annual production rate. A JBS machine is located below a frozen panel with three JBS machines available for operation. Two machines actively mine at any given time while the third is moving, setting up, or undergoing maintenance.
We have successfully packaged approximately 174.5 million pounds (100% basis) since we began mining in 2014.
Initial processing
We carry out initial processing of the extracted ore at Cigar Lake before shipping it to McClean Lake. To accomplish this, we:
| • | grind the ore and mix it with water to form a slurry in our underground circuit; |
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| • | pump the slurry 500 metres to the surface and store it in one of two ore slurry holding tanks, where it is blended and thickened to remove excess water; and |
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| • | the final slurry, at an average grade of approximately 16% U3O8, is pumped into transport truck containers and shipped to McClean Lake mill on a 69-kilometre all-weather road. |
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Water from this process, including water from underground operations, is treated on the surface. Any excess treated water is released into the environment.
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