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Tectonic movements have
endowed enormous mineral resources to the Central Andes
region in South America. Consequently, the Central Andes
region attracts major exploration and mining activities.
The region's resources include deposits at Chuquicamata
(largest copper porphyry system) and
Collahuasi.
For all the mineral resources she is endowed with,
Collahuasi is one of the harshest, inaccessible and
almost uninhabitable places on Earth. It is a triumph
therefore that conditions and checks have been installed
in this region, facilitating the mining of the region on
a big scale. In fact, the Collahuasi mine has been
recently listed on the stock markets, further affirming
that the mine has come of age.
At Collahuasi everything is in superlatives: Collahuasi
in the rich Chilean Norte Grande is one of the largest
copper resources known anywhere in the world. The
project represents the single largest copper mining
investment ever at US$ 1.80 billion
* The mine has the largest single investment in Chilean
history
* The site is one of the world's highest and harshest at
4800 meters above mean sea level.
Location:
Collahuasi is located in Tarapaca region in Northern
Chile, 100 kilometers south east of Iquique and 150
kilometers north of
Chuquicamata.
The Chile is a narrow strip west of Andes mountain
chain, which divides it from Argentina. To the west is
Pacific Ocean while the Southern part of Chile faces
Antarctica.
Ownership:
*
Falconbridge
- 44%
* Minorco (now merged with Anglo American Plc) - 44%
* Japanese consortium led by Mitsui & Co - 12%.
Occurrence:
Collahuasi consists of two major copper porphyry
deposits, Rosario and Ujina. Rosario has been known from
1979 and Ujina discovered in 1991. Ujina geologically is
classic
copper porphyry,
resulting in the development of a thick, continuous zone
of secondary enrichment. Rosario, with an area of one
square kilometer is within the five km radius
hydrothermal alteration zone. Bornite and Chalcopyrite
veins occur in the porphyry at Rosario but are absent at
Ujina. Rosario has undergone post-mineralization
faulting
and is structurally complex. It is said that mining at
Collahuasi has a long history dating back to the Incas.
Studies:
Pre-feasibility studies were carried out by
Bechtel
and feasibility studies by Davy (Kvaerner Metals). A
joint venture Bechtel-Davy was formed to handle the
project. The resources as assessed are:
* Measured and indicated resources 2,054 million tonnes
* Inferred resources 1,054 million tonnes with an
average Copper content of 0.82%. The cutoff grade taken
was 0.4%.
Production was planned at 330,000 tonnes of copper and
50,000 tonnes of copper cathode annually.
Environment:
The
location is marked by a fragile environment and harsh
conditions:
*
High altitude
and thin air causing breathing difficulties
* Temperature of about 110C during daytime dipping to
below freezing levels at night
* No trees, rare animal life and no nearby human
settlement
* Lack of adequate water supplies around the deposit
* Blizzards, lightning storms and volcanic activity in
the region.
This kind of reality calls for special measures and some
of the measures taken at Collahuasi are:
* Comprehensive medical checkups before proceeding to
the site and immediately on arrival at the site
* Work adjusted to provide off days on a regular
cyclical basis
* Special non-conducting safety shoes in view of the
lightning storms
* Each employee receives special training in
environmental, health and safety aspects to cope up with
the conditions
* Permanent camp for the employees away from the mine
and at a lower altitude
* Snowmobiles and alpine huts throughout the property to
prevent exposure
* Carrying out hydro geologic investigations in support
of feasibility studies for ground water.
The mine has a regular environmental audit. With no
water-borne effluents this is a zero-discharge
operation. Water, being scarce, is recycled extensively.
Facilities specially developed:
*
Permanent access road to the site
* Slurry pipe line 200 kilometers long
* Deepwater Port
* Water resources from distant internally drained
Salar basin.
The project work was completed between 1996 and 1999 and
plans for
expansion
from the present 450,000 tonnes per year are under
consideration. Concern over the region's limited water
resources in the light of expansion plan has also been
voiced.
Outlook:
Collahuasi has had yet
another good quarter this year meeting the planned
production volumes. In April, Collahuasi also secured
brand registration of its copper products with the
London Metal Exchange (LME). In 2004, mining activities
will move from the Ujina pit to the adjacent Rosario ore
body, which has a lower copper grade. To compensate for
this, a study is under way to explore ways of increasing
milling capacity by 40,000 tonnes per day.
The success story of the Collahuasi mine has been
achieved through overcoming many an obstacle. The
Collahuasi mine is already one of the major copper
producers in the world and it appears that Collahuasi
will continue to hold this esteemed position for a long
time to come.
Maps courtesy of
www.theodora.com/maps
used with permission"
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