The international conservation group says work at the open caste Ok Tedi mine in the mountains of western PNG has polluted rivers, caused flooding and destroyed forests.

WWF says millions of tons of waste material from the mine pour into the Ok Tedi and Fly river systems each year, much of it outside the area originally predicted to be affected.

Broken Hill Proprietary Company Limited (BHP), which operates Ok Tedi and holds a 52% stake, announced earlier in August that it was reconsidering its role, saying that waste management procedures at the mine were not working.

BHP Chief Executive Paul Anderson said that with the benefit of hindsight, the company should never have become involved.

"The mine was not compatible with BHP's environmental values," Mr Anderson said.

BHP and its partner, the part-government owned Ok Tedi Mining Ltd, said they would continue operating the mine until the government, the local community and shareholders decided on its long-term future.

Ecomonic impact

On Wednesday, Prime Minister Sir Mekere Morauta asked the World Bank to help assess the impact of the mine's closure, which could seriously damage the country's fragile economy.

BHP says the Ok Tedi project accounts for 20% of the country's export income and 10% of its annual gross domestic product.

"A comprehensive, independent and balanced approach - one that focuses on all the mine's impacts, not only the environment - is necessary," Sir Mekere said.

But the head of the WWF programme in PNG, Peter Hunnam, accuses BHP-OTML of keeping the government in the dark by producing an environmental impact assessment that is "startlingly short on fundamental detail".

"At the very least, the PNG Government and the local people deserve a report that is complete and takes into consideration the fact that thousands of people will continue to live with this mine's toxic legacy for the next several generations," he said.

Mr Hunnam says BHP-OTML now has three obligations:

• an immediate end to river dumping,
• owning up to moral and environmental obligations to rehabilitate the river system,
• a comprehensive recovery programme to guarantee life and health in the area.

Another group, the Australian Conservation Foundation, said the issue was a test of Mr Anderson's professed ethical policies.