Teck, North America's largest producer of steelmaking - or coking - coal, said that inquiries from buyers had picked up recently and that it expects sales to be weighted toward the second half of this quarter after a slow start.

"I actually feel much better today than I did three weeks ago," Teck Chief Executive Donald Lindsay said on a conference call.

Teck blamed the weaker start on customers drawing down coal inventories following a fourth-quarter buying binge, sparked by global supply worries that were ultimately unfounded. The Lunar New Year holidays also crimped demand in Asia.

Shares of the Vancouver-based company, which also mines copper, gold and silver, were down 9 percent at C$29.70 in mid-afternoon trading. It was the best-performing stock on the Toronto Stock Exchange in 2016.

Teck has reached agreements with the majority of its coal customers for the first quarter, based on a quarterly benchmark price of $285 per tonne.

But since that benchmark was set in early December, spot prices have plunged to about $155 per tonne. Teck expects an average realized price this quarter of about 70 percent to 75 percent of the $285-per-tonne benchmark.

Teck forecast first-quarter steelmaking coal sales of approximately 6 million tonnes, down from 7.3 million tonnes last quarter.

But Lindsay said the miner's top priority was reducing debt, and it was aiming to get debt levels, possibly this year, below $5 billion from $6.1 billion at the end of 2016.

A surge in coal prices last year from below $80 a tonne to above $300 had raised expectations of mine restarts. Real Foley, Teck's coal marketing vice president, said less than 15 million tonnes of coking coal had come online globally and that there had been no restarts since last October.

The company forecast 2017 steelmaking coal production of 27 million to 28 million tonnes, but said output may be adjusted depending on demand. Teck, the world's second-biggest exporter of seaborne coking coal, reported an adjusted profit of C$1.61 per share in the three months to the end of December, ahead of analysts' consensus estimate of C$1.56.

(Reporting by Susan Taylor in Toronto, Nicole Mordant in Vancouver and Vishaka George and Vishal Sridhar in Bengaluru; editing by Sunil Nair, Paul Simao and G Crosse)

By Susan Taylor and Nicole Mordant