Market Survey on Copper - Indian Bureau of Mines

Ministro Alejandro Hales (formerly Mansa Mina)
This is a major discovery that was made between Chuquicamata and Calama. It
was initially estimated to have reserves of over 500 million tonnes grading over 1%
copper but was found to be geologically complex and have a high arsenic content and
work was stopped on it for some years. Work resumed in 2000, as a result of the
development of a process to treat high arsenic ores, the need for sulphide ore feed to
the mill when Chuquicamata's mining goes underground and to test bioleaching
technology. It is also possible that it may enable an expansion of the sulphide mill's
capacity.
Pollution
For many years Chuquicamata, particularly its smelter, was a byword for
pollution and the inhabitants of the Chuquicamata camp and Calama had serious
amounts of arsenic in their blood. This has changed drastically. The camp at
Chuquicamata has been closed and the inhabitants moved to Calama, away from the
dust and general pollution close to the mine.
The off gasses from the flash smelter, Teniente converter and Pierce-Smith
converters have a high enough sulphur dioxide content to allow sulphuric acid
production in a single absorption sulphuric acid plant which has improved sulphur
capture to 98%. The Corporation also planned some years ago to reduce arsenic
emissions by 97% but there have been no recent reports. Pollution of the River Loa,
which flows through Calama is a problem which is being addressed but little has been
reported.
3. Grasberg Open Pit, Indonesia
Located some 60 miles north of Timika, at Tembagapura in Irian Jaya – the
most easterly of Indonesia's provinces – on the western half of the island of New
Guinea, the Grasberg mine has the world's single largest known gold reserve and the
second largest copper reserves.
Copper is the primary commodity, with a proven and provable reserve of 2.8
billion tonnes of 1.09%. The reserve also contains 0.98g/t gold and 3.87g/t silver.
Ownership belongs to Freeport McMoran Copper & Gold (67.3%), Rio Tinto
(13%), Government of Indonesia (9.3%) and PT Indocopper Investama Corporation
(9.3%). Around 18,000 people work at the mine, which is operated by PT Freeport
Indonesia, a subsidiary of Freeport McMoran Copper & Gold.
The mine stands at the collision of the Indo-Australian and the Pacific tectonic
plates. Two distinct phases of intrusion have led to the production of nested coaxial
porphyry ore bodies and sulphide rich skarn at the margins, while sedimentary strata
includes Eocene clastic carbonate limestone with siltstones and sandstones near the
base.
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