In the Indonesian province of Papua, violence has broken out once again in the area around the Grasberg copper mine. Unidentified gunmen fired on police officers, injuring five.

The officers were patrolling the road that leads to the mine when they were attacked. In the last week, three people have been shot dead on the road: a security guard, a police officer and an Australian mining engineer. Indonesian police suspect that separatists who support Papuan independence may be behind the attack.

Even among those not necessarily calling for independence, the huge Grasberg concern is a source of friction: locals have complained about its environmental impact and their share of the revenue. It is also often seen as a symbol of unfair rule from Jakarta.

Grasberg sits on the world's largest gold and copper reserves on the Indonesian archipelago. It belongs to the US company Freeport Indonesia, which annually pays hundreds of thousands of dollars to the army and police for protection.

In 2002, three people were shot dead at the mine.

Photo of Grasberg open-pit copper/gold mine by SkyTruth