The Denver-based company, which has two operating mines in British Columbia and other Canadian development properties, had an adjusted net loss of US$28.5 million or 17 cents per share.
Analysts had been looking for a loss of just three cents per share during the quarter.
Thompson Creek's revenue was also below expectations, at US$117.1 million compared with the general estimate of $123.77 million.
A year earlier, Thompson Creek had US$99.4 million of revenue in the fourth quarter of 2012 as well as an $11.9 million adjusted net loss, or seven cents per share.
The adjusted losses exclude non-cash items required under standard U.S. accounting. Including those items, Thompson Creek's net loss was US$120.5 million or $1.24 per share in the fourth quarter.
Thompson Creek produces a variety of commodities including molybdenum and copper — two widely used industrial metals — as well as gold and silver.
Its Thompson Creek moly mine and mill are in Idaho while its new Mt. Milligan copper and gold mine and its Endako molybdenum mines are in British Columbia.
The company said Thursday that it will suspend operations at its Thompson Creek molybdenum mine by the end of this year, due to persistent low prices for the base metal.
The company has also reduced its reserve estimates for the Endako moly mine in British Columbia to reflect a lower price for the metal.
As a result of the two measures, Thompson Creek recognized non-cash impairments to the value of those assets. At the Idaho mine, the pre-tax charge was US$129.4 million and at the B.C. mine the writedown of its 75 per cent share of Endako was $64.7 million.
During the fourth quarter, Mt. Milligan achieved commercial production levels.
"Our most significant achievement in 2013 was the commissioning and start-up of Mt. Milligan Mine," said Jacques Perron, the company's chief executive officer.
"As expected, our financial results were negatively impacted in the fourth quarter of 2013 as a result of Mt. Milligan revenue and costs being reflected in operating income rather than in start-up costs, as required by U.S. GAAP.
"Additionally, as a result of declining molybdenum prices, we had non-cash asset impairments at both of our molybdenum mines, which significantly impacted our non-cash operating results."Suggest a correction