The miner says unless the supply-demand balance improves it may take further steps to reduce production in the fourth quarter.
The warning came as Teck said it earned a profit attributable to shareholders of $63 million or 11 cents per share in the quarter ended June 30, down from $80 million of 14 cents per diluted share in the same quarter last year.
Excluding one-time items, Teck says it earned an adjusted profit of $79 million or 14 cents per share for the quarter, up from $72 million or 13 cents per share a year ago.
Revenue totalled nearly $2 billion, down slightly from just over $$2 billion in the same quarter last year.
Teck said prices for many of the major commodities it produces fell in the quarter, putting pressure on its margins and profits, offset in part by the weaker Canadian dollar.
The company's average realized price for coal in the quarter was US$95 per tonne, down from $111 a year ago, however in Canadian dollars terms the average realized price slipped to $116 per tonne from $122 last year.
The company is one of the country's largest mining companies with major zinc, copper, coal operations in Canada and around the world.
The coal industry has been hit by a glut of supply from low-cost Australian producers as well as dropping demand from a slowing Chinese economy.