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SANTIAGO, Nov 28 (Reuters) - Copper output at world No. 1 copper producer Codelco rose 4 percent year-on-year in the nine months to end-September, boosted by new mine Ministro Hales, but a continued slide in the price of the base metal ate into profits.
The Chilean state-run miner produced 1.23 million tonnes of copper in January to September, a 4 percent rise from a year ago, it said on Friday.
However, pre-tax profit fell 14 percent to $2.3 bln, which Codelco said was largely due to a slide in the price of copper , down around 14 percent year-to-date.
Codelco is battling falling ore grades at its decades-old flagship mines, and is seeking to implement an ambitious $27 billion multi-year investment plan to open new projects and revamp older ones.
Ministro Hales, which has been in its ramp-up period in 2014, is emblematic in many ways both of Codelco's hopes and its challenges.
The mine produced 109,000 tonnes of copper in the January to September period, the chief contribution to Codelco's rise in production.
But it has been dogged with problems at its key roaster, which is designed to reduce levels of arsenic in the ore to make copper concentrate saleable for the global market.
That led Codelco to cancel some sales to China earlier this year.
The roaster is currently undergoing repair work and will restart around Dec 4, said chief executive Nelson Pizarro at a conference following the results.
Pizarro forecast that copper prices will average around $3.00 per pound in 2015. The price has averaged $3.13 per pound in 2014, according to figures from state copper commission Cochilco. (Reporting by Fabian Cambero, Writing by Rosalba O'Brien; Editing by Chizu Nomiyama)