Metals miner Straits Resources Ltd has officially re-opened the Hillgrove antimony, gold and tungsten mine near Armidale in New South Wales after four years of development.

Chief executive Milan Jerkovic said the Perth-based company had invested $120 million in the project so far.

The mine was acquired from a private company in April 2004 for $8 million.

It had produced more than 720,000 ounces (oz) of gold and 50,000 tonnes of antimony, which is largely used in flame retardant applications.

Straits Resources plans to produce 20,000 oz of gold, 10,000 tonnes of antimony and 30 tonnes of tungsten from the mine each year.

The gold and antimony will be produced as metal ingots and the tungsten as a concentrate.

Straits Resources expects to complete the de-merger of its 47 per cent held subsidiary, coal miner Straits Asia Resources Ltd, by mid October, leaving the parent entity to focus on metals production.

At 1438 AEST, Straits Resources shares were up nine cents, or 2.34 per cent, at $3.93. – Associated Press