(Adds confirmation from Codelco that mine still at 65 pct capacity)
By Anthony Esposito and Fabian Cambero
SANTIAGO, April 21 (Reuters) - World No.1 copper producer Codelco said on Thursday its Andina mine in central Chile was still operating at 65 percent capacity after a tailings duct had ruptured and caused a temporary leak after storms over the weekend.
A mudslide caused by torrential downpours had ruptured the duct, the company said late Wednesday. The rains forced the suspension of operations at a number of mines. Codelco had said on Monday that due to the rains Andina, which is north of the capital Santiago, was operating at 65 percent capacity.
While the storm was still dumping rain on Andina on Sunday, state-run Codelco said it "made the mistake of sending tailings down the duct towards the Ovejeria tailings dam, without having first inspected it, bearing in mind the adverse climatic conditions."
After between half an hour and an hour, the company said it realized the error and stopped the process.
An inspection revealed some tailings "had leaked through the damaged section of the duct, running through a ravine," said Codelco.
Codelco said that mining and plant activities at Andina were operating "normally" but added that "our capacity has been reduced to 65 percent due to the use of another tailings dam." Andina produced 224,000 tonnes of copper in 2015.
Codelco said authorities had been informed and that it was initiating an investigation and sending out specialized crews to clean up the area. In the meantime, those responsible for management of the tailings process had been suspended pending the investigation.
The company said it considered the event "serious", given that it is the second environmental incident at Andina in recent months.
In February, the company temporarily suspended operations at the mine after a copper concentrate duct ruptured. (Additional reporting by Gram Slattery; Writing by Anthony Esposito and Gram Slattery; Editing by Chizu Nomiyama and James Dalgleish)