BY BRIAN WAWN, PROJECT MONITOR
Situated in the Indonesian province of Papua, Grasberg (“grass mountain”) is the largest copper-gold mine in the world.
Mainly open cut, Grasberg is undergoing a major underground expansion. The operator, Freeport Indonesia (the subsidiary of a US company), plans to spend US$700 million per year over the next five years on the expansion.
Grasberg has been operating since 1990, following the depletion of nearby Ertsberg (“iron mountain”), which operated from 1972 to the late 1980s.
Ertsberg was first discovered in 1936 by a Dutch geologist, Jean-Jacques Dozy, but it took Freeport more than 20 years to become aware of his work. .
The development of the area has been an engineering triumph, led originally by engineering contractor Bechtel.
The mines are at an altitude of around 4,000 metres (nearly 14,000 feet). The initial development required a 120-kilometre road from the coast through thick jungle, followed by an aerial tramway for the final step of the journey to the mine.
Once mined, ore goes through first-stage crushing. It is then transferred by conveyor 600 metres (2,000 feet) down the mountain for additional crushing and then by ore-passes (chutes) to a processing complex a further 1,000 metres (over 3,000 feet) down. This complex includes grinding and flotation facilities. The resulting concentrate is sent in slurry form via three pipelines to Amamapare on the coast, from where it is shipped for smelting overseas.
Production in 2011 (contained metal) was 360,000 tonnes of copper and 1.3 million ounces of gold. The remaining mine life is nearly 40 years.
Ertsberg and Grasberg have been kind financially to both Freeport and the Indonesian government.
But they have been accompanied by controversy.
First, critics (including some in the Indonesian government) allege that mine waste and tailings from processing have been washed into surrounding rivers and wetlands, making them unsuitable for aquatic life.
Second, Freeport has been embroiled in political controversy.
The Free Papua Movement (OPM), an independence group, has attacked the mine several times, starting in 1977. Attacks from other sources (often unknown) also occur from time to time (an Australian Freeport employee was killed in an attack in 2009).
Production was disrupted by a serious strike, marked by violence, in 2011.
The Indonesian military has a long-established presence in the area, receiving payments from Freeport and dealing at times roughly with strikes at the mine and local protests against it.
Freeport and its consultants and contractors have shown enormous technical skill at Ertsberg and Grasberg.
But to realise the full potential of Grasberg, Freeport may need to show increasing political skill as well. And the Indonesian government may need to deal more successfully with festering unrest in Papua than it has to date. And the Indonesian military may need be less opaque and more gentle in its dealings with local people in the area.
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