First Nickel said all other workers have reported in safely. The two workers killed were contractors and not unionized, the company added.
Mine Mill 598 Unifor president Anne Marie MacInnis said one of her health and safety representatives is negotiating to be involved in a joint investigation with the company, despite the workers not being members.
All underground activities, except for emergency requirements, have been suspended at the mine.
The Ministry of Labour has inspectors on the scene.
More to come