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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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