50K litres of uranium-contaminated water leaks into ground at Cameco's Key Lake mill

The Canadian Nuclear Safety Commission is investigating after a large water spill at a closed uranium mill in northern Saskatchewan.

Workers at Cameco's Key Lake uranium mill had flooded a section of the building to prevent the spread of radon gas. In June, workers noticed that 50,000 litres of water had leaked through the concrete floor into the ground.

Readings from a test well showed groundwater near the spill contained ten times more uranium than is normally allowed to be released under commission guidelines.

"Right now, it appears that uranium is isolated but there is more work that needs to be done," said commission project officer Richard Snider.

Camecosaid it is currently monitoring the area and coming up with a plan to clean up the area. Readings from other test wells in the area have not shown signs of contamination, which suggests the water has not spread far.

In similar cases, the contaminated water has been pumped out of the ground to fix the situation.

"If you have contamination, you're looking at something like pump back wells where you're pulling the groundwater up and then you're treating that water," said Snider. "Particularly if the contamination extends underneath the building. It can be quite difficult or costly to demolish buildings in order to dig up the material."

The leak happened in the mill's molybnenum plant, where waste chemicals are removed from the uranium ore. The area where the leak occurred has been closed off to workers.

The commission said it's not concerned about the leak reaching any surface water or plants or animals in the area. Regardless, Snider said the spill needs to be cleaned up.

"I think it's important to make sure that it's addressed because you know you never like to see contamination groundwater contamination even if it is isolated but it is as far as a risk it does remain low risk," he said.

Cameco closed the Key Lake mill last year due to low uranium prices.

The company is expected to submita plan to the commission over the next few weeks on how it will sink more monitoring wells to better determine the spread of the contaminated water, as well as an action plan to remove it.