Market Survey on Copper - Indian Bureau of Mines

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10. Andina Copper Mine, Chile
Situated some 50 km northeast of the capital, Santiago, the Andina mine was
discovered in 1920 but production did not start until 1970. It consists of the Rio
Blanco underground (block cave) mine and the Sur Sur open pit and an underground
concentrator. Unlike other Codelco mines, it does not have its own smelter.
Geologically it consists of about half the Los Bronces-Rio Blanco complex of
mineralised breccias, the other half being owned and mined by the Los Bronces mine
of Compania Minera Disputada de la Condes which is in turn owned by Anglo
American.
Originally owned by the American Cerro De Pasco Corporation, who brought the
mine to production, it has been gradually built up by Codelco and is now the subject of a
major expansion scheme. At the end of 2007, reserves and resources in the mining plan
totalled 5,698 million tonnes grading 0.78% copper containing 44.3 million tonnes of metal
and additional identified resources of 11,342 tonnes grading 0.52% copper containing 59.6
million tonnes of metal.
The orebodies are at considerable heights, between 3,000 and 4,200 metres and
operations can be severely affected by the weather. Originally the mine was only the
underground block cave and an underground concentrator with an 'hotel'/bunkhouse where the
workers live when the Rio Blanco valley is impassable in the winter. Now the Sur Sur and
Don Luis breccias above and to the south of the underground mine are being worked as open
pits. Production in 2007 was 218,322 tonnes of extractable copper and 2,525 tonnes
molybdenum in concentrate from the 72,000 tonnes per day concentrator.
Work is now under way on the Andina Phase I Development Project which aims to
raise mill capacity to 92,000 tonnes per day and is expected to be complete by November
2009.
Pre feasibility studies on raising mill capacity to over 200,000 tonnes per day by 2014
should be complete this year. Deep drilling to prove up resources to sustain such a production
rate continues. No estimates of the likely copper output at a milling rate of 200,000 tonnes per
day have been given and cannot be until the deep drilling campaign is complete.
One of the mysteries of Andina is why it did not buy Compania Minera Disputada de
las Condes when Peñarroya was prepared to sell it for a very low price in 1972. It went to
Enami who subsequently sold it for a handsome profit to Exxon Minerals for US$97 million.
It would have given Codelco complete control of the district. When Exxon finally did decide
to sell in 2002, Codelco expressed interest but were not prepared to match the US$1.3 billion
that Anglo American were prepared to give for it
Rock glaciers have been seriously intervened by Andina since the late 1980s,
when it started to deposit several million tons of waste rock on top of rock glaciers,
resulting in their acceleration and partial destabilisation. Since then, 2.1 km 2 of rock
glaciers with a water equivalent of more than 15 million cubic metres have been
affected by Andina, including the partial removal of rock glaciers.
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