The Diavik Diamond Mine in the Northwest Territories says 450 million litres of wastewater spilled due to a broken pipeline.

The spill took place on Feb. 7 but wasn't reported until late last week.

The Northwest Territories government says pipeline operators did not believe it needed to be reported as the wastewater leaked into a containment pond that was its final destination.

The government says its inspectors have confirmed the spill is within the pond and none has been released into the environment.

The spill report says the water used in mining operations contains sewage and mine tailings and the area of contamination is 5,000 cubic metres.

The Northwest Territories government says it has requested that Diavik divert and repair the pipeline and that the company is addressing the issue appropriately.

The mine is roughly 300 kilometres northeast of Yellowknife and is owned by Rio Tinto, a global mining giant that has head offices in the United Kingdom and Australia.

This report by The Canadian Press was first published March 21, 2023.