PERTH (miningweekly.com) – Copper miner Altona Resources has extended the mine life of its Kylylahti underground mine, in Finland, by more than a year, following an increased resource and reserve estimate.
The ASX-listed Altona reported on Thursday that ore reserves at the Kylylahti mine, which forms part of the Outokumpu project, had increased by some 16%, to 4.2-million tonnes, grading 1.6% copper, 0.73 g/t gold and 0.63% zinc, for 66 700 t of copper, 97 700 oz of gold and 26 100 t of zinc.
Contained copper also increased by 10%, while copper grade decreased by some 5%.
“We are delighted by this latest upgrade at Kylylahti. Since starting mining in early 2012, we have more than replaced mining depletion of reserves and the deposit has consistently delivered better grades once it has been defined by underground drilling and development,” said Altona MD Alistair Cowden.
He added that the deposit had been subject to definition drilling to around 540 m vertical depth, noting that there was potential that definition drilling below this depth would also improve reserve grade.
“The increase in mine life is particularly pleasing as Kylylahti was anticipated to be mined out by June 2019, in the absence of no further extensions to the deposit. Mining is now scheduled for completion in late 2020,” said Cowden.
He added that the deposit remained open at the lower limit of drilling, adding that a programme of deposit-extension drilling had now started.
“Success in this drilling, combined with the reserve upgrade could underpin a higher production rate or a longer mine life,” he said.
The Kylylahti mine produces some 550 000 t/y of ore, which is treated at the refurbished Luikonlahti mill, with yearly production reaching some 8 000 t of copper, 8 400 oz of gold and 1 600 t of zinc.