TORONTO (miningweekly.com) – Despite rising output from its North American molybdenum mines, base metals miner Thompson Creek Metals on Thursday announced that it would suspend molybdenum production at its key Thompson Creek (TC) mine, in Idaho, as soon as the current production phase is complete.

Given declines in molybdenum prices and projected operating costs at the TC mine for 2015 and thereafter, Denver, Colorado-based Thompson Creek had in October 2012 suspended waste stripping activity associated with Phase 8.

However, since that time, the molybdenum market had continued to weaken and, as a result, management had decided to put the TC mine on care and maintenance when the mining and processing of Phase 7 ore is complete, which was expected to be in the fourth quarter.

The miner, which had started to diversify its portfolio to include copper and gold, is ramping up output from its new flagship $1.5-billion Mt Milligan copper/gold mine, in British Columbia. The operation reached commercial production on Tuesday.

Thompson Creek said that it would restart operations when the molybdenum market conditions improve, and management would continue to evaluate potential economically viable options for Phase 8.

The decision to place the TC mine on care and maintenance has triggered an asset impairment. During the fourth quarter ended December 31, the company recognised a pre-tax, noncash write-down of the TC mine property, plant, equipment assets and materials and supplies inventories of $129.4-million, representing a write-down to the assets' estimated fair value.

Also during the period, Thompson Creek revised the proven and probable reserves for both of its molybdenum mines using a $10/lb molybdenum oxide price, which resulted in a significant reduction in reserves at the Endako mine, also located in British Columbia.

This revision was another triggering event to evaluate for potential long-lived asset impairment, resulting in an additional pre-tax, noncash property, plant and equipment and materials and supplies inventory write-down of $64.7-million, which represented the company's 75% share of Endako mine assets' estimated fair value as of December 31.

Thompson Creek also on Thursday reported a fourth-quarter net loss of $210.5-million, or $1.24 a share, compared with a loss of $484.4-million, or $2.87, a year earlier.

Revenue rose to $117.1-million from $99.4-million, boosted by increased copper and gold sales.

The adjusted loss widened to $28.5-million, or $0.17 a share, from $11.9-million, or $0.07 a share.

On the TSX, Thompson Creek’s stock rose as high as C$3.33 apiece on Friday morning.