In 1936 Dutch geologist Jean-Jacquez Dozy visited Indonesia to scale Jayawijaya Mountain glacier in the Irian Jaya province in western Papua. While there, he made notes of a peculiar black rock with greenishcoloring, and spent several weeks estimating the extent of the gold and copper deposits. In 1939, he filed a report about the Ertsberg (Dutch for "ore mountain"). He was working for Nederlandsche Nieuw Guinea Petroleum Maatschappij (NNGPM), an exploration company formed by Shell in 1935, with 40% Standard Vacuum Oil (Mobil) interest and 20% Far Pacific investments (Chevron subsidiary).
In March 1959 the New York Times published an article's revealing the Dutch were searching for the mountain source of alluvial gold which had been flowing into the Arafura Sea. Geologist Forbes Wilson, working for the Freeport mining company in August 1959 after reading Dozy's 1936 report, immediately prepared to explore the Ertsberg site. In 1960 the expedition, led by Forbes Wilson and Del Flint, confirmed the huge copper deposits at the Ertsberg. It was financed by Freeport Sulphur. At the time the company was implicated in a nickel stockpiling scandal under investigation in the US Senate by John F. Kennedy.. Its directors included Godfrey Rockefeller, Texaco chairman Augustus Long, and Robert Lovett.
With permission from the Indonesian government (though West Papua was not part of the Republic of Indonesia at the time), Freeport built the Ertsberg mine at 4,500 metres (14,000 ft) above sea level. It officially opened in 1973 (although the first ore shipment was in December 1972), and was expanded by Ertsberg East, which opened in 1981.
Steep aerial tramways are used to transport equipment and people. Ore is dropped 600 metres (2,000 ft) from the mine, concentrated and mixed with water to form a 60:40 slurry. The slurry is then pumped through pipelines to the port at Amamapare, dried and shipped. Each tonne of dry concentrate contains 317 kilograms of copper, 30 grams of gold and 30 grams of silver.
In 1977 the rebel group Free Papua Movement attacked the mine. The group dynamited the main slurry pipe, which caused tens of millions of dollars in damage, and attacked the mine facilities. The Indonesian military reacted harshly, killing at least 800 people .
By the mid-1980s, the original mine had been largely depleted. Freeport explored for other deposits in the area. In 1988, Freeport identified reserves valued at $40 billion at Grasberg (Dutch, "Grass Mountain", just three kilometres (two miles) from the Ertsberg mine. The winding road to Grasberg, the H.E.A.T. (Heavy Equipment Access Trail), was estimated to require $12 million to $15 million to be built. An Indonesian road-builder who had contributed to the Ertsberg road took a bulldozer and drove it downhill sketching the path. The road cost just $2 million when completed.
The 2003-2006 boom in copper prices increased the profitability of the mine. The extra consumption of copper for Asian electrical infrastructure overwhelmed copper supply and caused prices to increase from around $1500/ton to $8100/ton ($0.70/lb to $4.00/lb).
Source : en.Wikipedia.org