The writedown was mostly related to its stake in the active Fort Hills oil sands mine in landlocked Alberta, while the company warned of another potential $1.13 billion future writedown should its $20.6 billion Frontier project not receive federal permitting expected by next week.

The company wrote off C$910 million on Fort Hills related to lower market expectations for future Canadian oil prices.

CEO Don Lindsay said Friday ongoing global economic uncertainty negatively impacted commodity prices in the most recent quarter, which had continued into 2020. This had been exacerbated by the effect on markets from the coronavirus, along with impacts of severe weather conditions in British Columbia, followed by blockades on rail lines.

Teck said it had lowered production and temporarily shut down its Neptune Bulk Terminals export facility in Vancouver because the virus had weakened demand over the short term and because of First Nation railway blockades in British Columbia.

The company expects 2020 steelmaking coal output of between 23-25 million tonnes, down from 2019 output of 25.7Mt, with a recovery expected in 2021 to 26-27Mt.

Copper production for the full year is expected to be between 285-300Mt, comparable to 2019 output of 297Mt.

"Our focus remains on those aspects of our business within our control including executing on our Quebrada Blanca phase two and Neptune Bulk Terminals expansion projects, taking steps to improve our steelmaking coal logistics chain, controlling costs and implementing our RACE21 programme, which has exceeded initial expectations," said Lindsay.

Headline profit for the December quarter fell 76% year-on-year to C$122 million, or 22c per share, well below market forecasts calling for 39c per share, and compared with profit of $500 million, or 87c per share, in the comparable prior-year period.

Revenue fell 18% year-on-year to about $2.66 billion, compared with nearly $3.25 billion in the same quarter of 2018.

Teck's Toronto-quoted equity (TSX:TECK-B) fell to a fresh 12-month low Friday at $14.55, giving it a market value of $7.9 billion (US$6 billion).