At least three workers at Cameco's Cigar Lake mine are confirmed to have the virus and another 100 workers are showing symptoms.
The illness broke out a week ago at the mine site when workers started showing symptoms including diarrhea, vomiting and nausea.
Rob Gereghty with Cameco said the company is taking measures to prevent the virus from spreading by closing recreational facilities.
Dr. Moliehi Kahaketla is the Deputy Medical Health officer for the three northern health regions.
She said the number of cases has been steadily decreasing since the outbreak started.
“Anybody who is having diarrhea and vomiting is not presenting for work, they are pretty much staying in their rooms until at least 48 hours after the last symptoms,” Kahaketla explained.
Kahaketla said the company is educating workers on the importance of proper hand washing.
About 600 people work at the Cigar Lake mine, which is about 660 kilometres north of Saskatoon.