BHP boosts copper resources at Spence

Resources at BHP Billiton‘s (BHP-N) Spence copper mine in northern Chile has grown by nearly 700%, following a four-year, US$30-million brownfield exploration program.

The increase reflects a hypogene extension of the supergene mineralization of the current resource. As a result, BHP has added 2.3 billion tonnes grading 0.43% copper to the resource. 

An exploration and development report for the quarter ended Dec. 31 notes that the Spence project has 2.69 billion tonnes. 

BHP says this resource boost, plus the previously reported resource increases at the Escondida copper mine in Chile and the Antamina copper-zinc project in Peru, show the fruits of the company’s extensive brownfield exploration program. 

Last July, BHP expanded resources in the Escondida mining complex by 129%, and at Antamina by 32%. 

The increase at the 57.5%-owned Escondida project came after a four-year, US$381-million drill program, which delineated initial resources at the nearby Pampa Escondida and Pinta Verde deposits, and boosted resources at Escondida by 40%.

Escondida contains 3.1 billion tonnes of 0.75% copper in the measured category, and 4.7 billion tonnes of 0.59% copper in indicated. 

The 33.8%-owned Antamina has 187 million measured tonnes at 0.85% copper and 1.01 billion indicated tonnes at 0.91% copper. 

Last year, the miner drilled 542,000 metres across the Pilbara, adding 20% to the Western Australian iron ore project’s resource and bringing it to 19.3 billion tonnes, while completing a 3-D seismic survey and deep drilling on an exploration target in Saskatchewan’s potash basin. 

It also drilled 267,000 metres in Australia’s Bowen basin to increase confidence in the resource underpinning its development coal projects: Daunia and Caval Ridge. 

During 2011’s last half, the diversified producer committed more than US$26 billion to its world-class growth pipeline. 

For the quarter ended Dec. 31, it approved mine development at Caval ridge and expansion of the Peak Downs operation, also in Australia. BHP says the projects will add to its coal capacity. 

It earmarked another US$1.2 billion for the first phase of the Olympic Dam project in Australia following environmental approvals and the indenture agreement by the South Australian parliament. 

On greenfield exploration, BHP spent US$532 million during the half-year, of which US$451 million was expensed.