Market Survey on Copper - Indian Bureau of Mines

Concentration and separation involves two steps, carried out in a bulk flotation
plant and a molybdenum plant. Bulk flotation involves rougher, scavenger and cleaner
flotation with associated concentrate regrind stages and is optimised by the Metso
Minerals VisioFroth system. Bulk copper-moly concentrate goes to a thickener prior
to treatment in the molybdenum plant. Flotation tails go to tailing thickeners. About
70% of process water is recycled.
The concentrate slurry is piped via Salamanca and Illapel to the purpose-built
port of Los Vilos (Punta Chungo) where it is dewatered for shipment. Los Pelambres
treats the water extracted for use in irrigating a nearby eucalyptus plantation.
In April 2004, the Chilean government approved an Environmental Impact
Statement covering a second tailings disposal site, Mauro. Construction would allow
Los Pelambres to mine an additional 2,000Mt over the life of mine and extend that
life from 22 to 47 years at the current processing rate of 114,000t/d. Alternatively, the
concentrator capacity could be increased to 175,000t/d, possibly in stages.
Construction of the Mauro tailings dam was completed in December 2008 at a cost of
$600m.
Production
In its first full year, 2000, Los Pelambres processed 34Mt of ore to produce
298,900 tonnes of copper-in-concentrate and 5,450 tonnes of molybdenum. In 2003,
the plant treated an average of 113,300 t/d of ore grading 0.91% copper, with average
recovery 89.9%, to produce a total of 826,500 t of concentrate grading 40.9% copper.
Payable copper-in-concentrate totalled 326,700 t and payable molybdenum, 8,700
tonnes.
2004 saw a 7.3% increase in output to 350,600 t payable copper-in-concentrate
despite a lower average ore grade of 0.88% Cu, mainly because of the pebble crusher
added to the grinding circuit during 2003. However, the payable molybdenum
tonnage fell to 7,900 t. In 2005, the copper ore grade fell again to 0.80% and payable
copper-in-concentrate output dropped to 322,800 t as the mine focused on maximising
molybdenum production, which rose to the 2003 level of 8,700 t.
A $192 m expansion project that was completed in 2007, boosting production
capacity of the mine to 130,000 t/d. By the end of 2008, the mine produced 136,000 t
of ore per day, graded at 0.76% ore. A plan for further plant expansion was approved
in July 2008. The expansion will boost copper production to 90,000 t a year from
early 2010. By June 2009, the project was 47% complete and within the allotted $1bn
budget.
8. Morenci Copper Mine, Arizona, USA
The Detroit Copper Company started mining at Morenci, 16km south of Silver
City, Arizona, in 1872. Copper Queen Consolidated Mining bought the property in
1885, with the company name being changed to Phelps Dodge in 1917.
184
Contd…..