Carajas Iron Ore Mine, Brazil

The Carajás Mine is the world's largest iron ore mine and is located in the state of Para in Northern Brazil.

Fully owned by Brazilian miner Vale (CVRD), the mine holds 7.2 billion metric tons of iron ore in proven and probable reserves.

The Carajas region boasts the richest reserves and concentrations of iron ore anywhere in the world and was discovered entirely by accident in the late 60s when a US Steel Helicopter was forced to land on a hill in the area to refuel. Surveyors on board noted the baron state of the hill and subsequently discovered that the iron content was as high as 66%.

Other mineral deposits were discovered later; Carajás is rich not only in iron ore but also ores for manganese, copper, tin, aluminium and even gold.

US Steel wanted to develop the Carajás iron deposit but the Brazilian Government was unwilling to hand control over to a foreign company. Brazil is currently the world's largest exporter of iron ore with annual production of over 200Mt.

In 1970 the Brazilian government opted instead to create a joint venture company, Amazonias Mineração SA (AMZA), of which 51% was owned by Vale and 49% was owned by US Steel.

US Steel subsequently withdrew from the joint venture in 1977 by selling its share to CVRD for $55m. Vale produced 237.9Mt of iron ore at the Carajas Mine for 2009, against 301.7Mt in 2008.

In 2007, Vale approved an expansion project of the Carajas mine. The $2.48bn project, Carajas 130, currently under way, is expected to add 30 million tons a year to the current capacity of 100m tons a year. In 2009, $798m was diverted towards the project. The project will oversee the construction of a new plant including primary crushing, processing and classification units.

Significant investments in logistics will also be made. Originally scheduled for completion in the second half of 2009, the project was postponed. Commissioning has been re-scheduled for the first half of 2012 based on the concession of environmental issues. As of April 2010, work on the fourth car dumper as well as the buying of equipment is making progress.

To compensate for the delay in the completion of Carajas 130 project, another 10Mt/y brownfield project is under construction in the northern range of Carajas. The project, scheduled for completion in the first half of 2010, will increase the capacity of the current iron ore beneficiation plant by 10Mt/y.

Geology and reserves

The Carajás ores are found within Archaean iron formations. The volcanic sequence has been weathered to a depth of between 100m and 150m, while oxidation is observed to a depth of up to 500m in the BIFs of the ore zone.

The upper 80% of the reserve comprises a soft, friable enriched limonite near surface passing down into hematite to a vertical depth of around 300m. Hematite rich, but harder and more siliceous pods occur within the soft hematite, but also as a transition to the un-enriched BIF at depth.

The Carajás District contains known reserves of the order of 18 billion tons with an average grade of 65.4% Fe.

The reserves are distributed in a number of deposit groups, the largest of which is the North Range with - 6,200Mt @ 65.8% Fe, 0.038% P, 1.0% SiO2, 1.05% Al2O3, 0.45% Mn, 0.01% S, 0.02% KO, 0.03% Na2O and 1.88% LOI. The other reserves include: South Range, 35km to the south – 10,400Mt @ 66.3% Fe; East Ridge – 400Mt @ 65.9% Fe; and South Felix Ridge – 600Mt @ 62.8% Fe. The current production contains < 1% Al2O3, < 1% SiO2, < 0.03% P2O5 and < 0.3Mn, with about 10% lump and 90% fines.

The Carajás District contains 7.2 billion metric tons of proven and probable reserves as of 2009 estimates.

Mining

The operation utilises an open pit mining complex with an initial capacity of 35 million tons a year (tpy) – soon to be extended – a deep-water port near the city of Sao Luis, in the Northeastern State of Maranhao, with a handling capacity of vessels of up to 280,000dwt, and a single track 1.6m gauge railway line of approximately 890km interconnecting the mine to the port.

Production

Vale's iron ore production for 2007 at Carajas was 296 million metric tons, an increase of 12% on the previous year.

The Carajas Mine also relinquished: 17.6 million metric tons of pellets; 247,900 metric tons of finished nickel; 9.1 million metric tons of bauxite; 4.3 million tons of alumina; 551,000 metric tons of aluminium; 1.3 million metric tons of kaolin; 2,500 metric tons of cobalt.

In 2009, three new annual records were made in terms of production of coal at 5.4 million metric tons, bauxite that reached 12.5 million metric tons and alumina at 5.9 million metric tons.