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Copper/Mining Process |
| How Rock Comes to
Life: Step-by Step Through the Mining Process |
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Our geologists discovered the Grasberg ore deposit in 1988. Grasberg contains one of the world's largest reserves of copper and gold. PT Freeport Indonesia's share of reserves from Grasberg and other deposits from the surrounding Grasberg Minerals District total more than 40 billion pounds of recoverable copper and more than 46 million ounces of recoverable gold. |
2 An ore sample from the Grasberg mine's high-grade central stockwork zone. The copper sulphide minerals present in the specimen are: chalcopyrite (brassy yellow-orange), bornite (dark blue-purple), covellite (violet/light blue), quartz (clear/round patches). The gold found in these minerals occur as particles too small to see within the copper sulphide minerals. There are 2.8 billion metric tons of ore in Grasberg and the surrounding deposits in the Grasberg Minerals district. While this sample holds higher values, the average ore in the deposits contains 1.09 percent copper and 0.98 grams per metric ton of gold. |
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3 Grasberg open-pit employees operate a fleet of heavy duty equipment and hundreds of vehicles, including huge electric shovels as pictured which fill massive haul trucks with ore. On an average day, these trucks move approximately 700,000 tons of rock, including ore and non-economic waste. The waste, called overburden, is crushed and placed in specially designed overburden deposit sites nearby. The ore is trucked to crushers and delivered to conveyors for transport to our massive mill/concentrator facilities. The Grasberg open-pit mine is in the central highlands of Papua. The highest point of the mine is more than 4,100 meters (approximately 13,500 feet) in elevation and the current deepest pit level is 3,400 meters (11,155 feet) |
4
In the Deep Ore Zone (DOZ) underground mine, an average of 40,000 tons of ore per day is mined, crushed and sent via conveyor belt to the mill. |
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5 The ore from Grasberg and DOZ mines is sent via conveyor and underground ore passes to the mill complex at an elevation of 2,900 meters (9,500 feet) above sea level. The mill facility is where the ore from the mine is crushed and processed to the end product from the PT Freeport Indonesia operation. |
6 The ore is crushed into a fine powder and sent to tanks where the minerals containing copper and gold are physically separated from the other non-economic rock particles in a process called flotation. The rock and water slurry is agitated in the tanks and alcohol based reagents are added to cause the copper and gold-bearing minerals to adhere to air bubbles, which are collected as copper concentrate. The process at PT Freeport Indonesia does not involve the use of cyanide or mercury, nor does it involve chemical alteration of the ore. |
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7 The material not recovered as concentrate in the mill is called "tailings." This finely ground material is transported to a government-approved deposition area in the lowlands portion of the project area called the Modified Deposition Area (see Tailings Management page 30). |
8 On average, the concentrate product contains approximately 30 percent copper and about one ounce of gold per ton. It is sent via a system of pipelines in a slurry of approximately 60- percent rock/40-percent water to the port facility approximately 70 miles away on the coast of the Arafura Sea. |
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9 At the port facility, the water is removed from the concentrate slurry by filters and kiln dryers. The final product - a dark gray powder with a moisture level of approximately 9% - is shipped in bulk carrier ships to smelters around the world. |
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Smelters and refineries process the concentrate, separating the gold from the copper, remove other non-economic minerals and rock particles, and produce copper cathodes and anodes. Material containing gold is shipped to precious metals refineries for further processing. |
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11
The smelters' copper products are sold globally to producers of wire, tubing and other copper products. The copper is then sold to manufacturers and fabricators who use the copper for thousands of different applications for our modern way of life. |
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Copper is a natural element in the environment and ispresent in and essential to the health of just about everyliving organism. Included in many of the foods we eat,copper is naturally regulated by our bodies. The body useswhat it needs and excretes the rest. The metal is notmagnified in living organisms, nor is it bio-accumulated in the food chain. Copper is nearly 100% recyclable and is the most recycled of the metals. Mined copper, however, is still required to keep pace with demand brought on by economic development throughout the world. New copper deposit finds are rare. Most of the operating copper mines around the globe are exploiting deposits that were discovered decades and even more than a century ago.
Demand for copper in 2004 outpaced supply. More than 11 million tons of copper were produced in concentrates from the world's mines in 2004. The PT Freeport Indonesia mine in Indonesia, one of the world's major suppliers, mined, processed and sold concentrates containing approximately 1 billion pounds of copper in 2004. We expect to sell 1.5 billion pounds of copper in 2005.
The world is hungry for copper not only because there is more development taking place, but also because modern technology requires more copper than ever before. Building construction accounts for approximately 40% of all copper use. The average new single family home in the U.S. uses 439 pounds of copper and the average new automobile contains more than 50 pounds of copper. Both of these averages have grown dramatically over the past several decades and demand is expected to continue to rise, especially in fast-developing regions of the globe such as China.
