The roaster, which is key to reducing the high arsenic levels in Ministro Hales concentrates, has experienced technical problems since it started to operate in mid-2014.
“It is still in the start-up stage,” the world’s largest copper producer said, confirming a comment made to Reuters.
Codelco added that it will inform the market once the roaster reaches its full capacity.
Earlier this year, Codelco’s ceo Nelson Pizarro said that the roaster was “going well”, following planned maintenance in November.
According to him, it was operating almost 20 hours per day, producing 1,000-1,200 tonnes of calcine.
The company did not say whether the roaster is still operating at that level.
Concentrates from the Ministro Hales division typically have an arsenic content level significantly above 0.5%.
That means they have to be treated at the roasting complex to reduce arsenic levels and make them suitable for processing at Codelco’s Chuquicamata to produce copper cathodes.
Given the issues with the roaster, Codelco has been blending
high-arsenic concentrates with clean feeds so it is able to sell the material in China.
There were rumours in the market this week that Chinese smelters have signed a long-term contract
with Codelco for blended materials.