Grasberg Mine - Environment

Environment

The concentrator's tailings, generated at a rate of 230,000 tonnes per day, are the subject of considerable environmental concern, as they wash into the Aikwa riverine system and Arafura Sea. Some 130 square kilometres (50 sq mi) (eventually 230 square kilometres (89 sq mi)) of lowland areas along the Aikwa River, are covered by braided sedimentary channels indicative of high sediment load (similar to glacial runoff). Native fish have nearly disappeared from now-turgid waters of the Aikwa River. The overburden (700 kt/d) remains in the highlands, up to 480 m deep and covering 8 square kilometres (3 sq mi). Its acidic runoff, dissolved copper, and the finer material gets washed into the headwaters of the Wanagon River. It settles out along the river course and then into the ocean, and will continue to do so indefinitely. Freeport's official response is that overburden is placed in the highlands as part of its Overburden Management Plan, at "sites capped with limestone and constantly monitored. Tailings are transported to the lowlands in a designated river system. Once reaching the lowlands, they are captured in an engineered system of levees built for that purpose." Freeport states that its discharges meet regulatory requirements.

In 1995, the Overseas Private Investment Corporation (OPIC) revoked Freeport's insurance policy for environmental violations of a sort that would not be allowed in the US. It was the first action of this sort by OPIC, and Freeport responded with a lawsuit against them. Freeport states that this revocation was based on a misunderstanding, the result of a single 1994 visit to Grasberg; the company later underwent an independent environmental audit by Dames & Moore, and passed. In April 1996, Freeport canceled its policy with the OPIC, stating that their corporate activities had outgrown the policy's limits. However, the OPIC report was later publicly released and exposed gross misrepresentations by Freeport.