FCX operates under a Contract of Work (CoW) agreement with the government of Indonesia, which allows Freeport to conduct exploration, mining and production activities in a 11,100-hectare (27,400-acre) area (Block A).

While there, he made notes of a peculiar black rock with greenish coloring, and spent several weeks estimating the extent of the gold and copper deposits in the area.

He was working for Nederlandsche Nieuw Guinea Petroleum Maatschappij (NNGPM), an exploration company formed in 1935 by Bataafse Petroleum Maatschappij (BPM, a Royal Dutch Shell subsidiary) (40%), Standard Vacuum Oil Company (40%) and Far Pacific investments (a Standard Oil of California subsidiary) (20%).

Although the Dozy report did not mention nickel, Van Gruisen applied to the Netherlands government for an exploration concession for an area of 100 square miles (300 km2) surrounding Ertsberg.

[10] In March 1959, the New York Times published an article revealing the Dutch were searching for the mountain source of alluvial gold that had been washed into the Arafura Sea.

[11] Van Gruisen casually mentioned the Dozy report to Forbes Wilson, geologist and vice president of Freeport Minerals Co.,[12] who immediately recognized the mining potential of Ertsberg.

The directors of Freeport Sulphur at the time included Godfrey Rockefeller, Texaco chairman Augustus Long, George Mealey, and Robert Lovett.

Built at 4,100 metres (14,000 ft) above sea level in one of Papua's most remote areas, it involved a capital and technology input well beyond Indonesia's resources at the time.

The group dynamited the main slurry pipe, which caused tens of millions of dollars in damage, and attacked the mine facilities.

In 1988, Freeport identified reserves valued at $40 billion at Grasberg (Dutch, "Grass Mountain"), 3 kilometres (2 miles) from the Ertsberg mine.

Grasberg's milling and concentrating complex is the largest in the world, with four crushers and two giant semi-autogenous grinding (SAG) units processing a daily average of 240,000 tonnes of ore in 2006.

[22][23] The concentrator's tailings, generated at a rate of 700,000 tonnes per day,[17] are the subject of considerable environmental concern, as they wash into the Aikwa riverine system and Arafura Sea.

[17] 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.

[32][33] Violent ambushes near the Grasberg mine have occurred as early as August 2002, when Rickey Lynn Spier, Leon Edwin Burgon, and Bambang Riwanto, three contract school teachers were killed in the attack.

[34][35] Independent activists alleged multiple incidents such as the August 2002 attack appear to have been instigated by Indonesian forces, some including the TNI, Tentara Nasional Indonesia, who are not fully subsidized by the government, leaving them dependent on being the source of security for extractive companies in an area such as Freeport.

[36] Although investigations by Polda Papua and FBI confirmed the perpetrator to be Antonius Wamang, JH, MK, DM, AA, GM, JK, EO, and YD.

Indonesian police indicated that Grant was killed by five shots he sustained to the neck, chest and stomach by unknown assailants using military-issue weapons.

Causes of friction are the mine's environmental impact on Papua, the perceived low share of profits going to local Papuans (Freeport's annual report shows it made $4.1billion in operating profit on revenue of $6.4billion in 2010) and the questionable legality of the payments made to Indonesian security forces for their services to guard the site.

[44][45] The miners were trapped inside a lower chamber while attending a refresher training course on work safety in underground mining areas.

According to the Freeport McMoran geological team, the collapse at the Big Gossan tunnel was caused by erosion of the ceiling, brought about by the continuous infiltration of the limestone wallrocks by corrosive acidic groundwater.

Seventy percent of Grasberg workers joined the strike, appealing for higher pay September 15, 2011, blocking roads, clashing with police and cutting the pipeline in several places.

[49] In October 2014, around 1,000 workers stayed home and demanded the firing of 50 managers as a result of a fatal accident at the Grasberg mine.