Teck Resources, Canada’s largest producer of coking coal, has lost C$18 billion in value in the last five years, the Institute for Energy Economics and Financial Analysis reported last week.

“Like most coal companies globally, Teck’s share price has declined by 80% in the past five years. That includes a more than 50% decline in the past 12 months alone,” the IEEFA notes. “It is very telling that Teck this week announced a write-down of its coking coal business by C$2 billion, acknowledging a massive and permanent diminution of its core coal business.”

Coal prices were down 20% over the third quarter of 2015 compared to the same period last year. The value of the Canadian dollar has fallen by almost the same amount, so the company’s “operating profits in Canadian dollars were insulated from the collapsing coal price by the combination of a falling currency, lower oil prices, and cost reduction initiatives,” Buckley writes.