The December quarter Gold Report of Aurum Analytics showed that the average all-in sustaining cost (AISC) for Australian and New Zealand mines was $A1,111/oz ($NZ1,201/oz). which was 5.3% lower than the previous quarter.
The report, supported by PCF Capital, showed that Evolution Mining Ltd’s Ernest Henry mine in Queensland was again the lowest cost producer with an enviable AISC of minus $A627/oz due to the fact gold is produced in association with copper mining.
Ironically Ernest Henry had the lowest grade gold ore to treat at a head grade of 0.56 grams/tonne.
This was followed by Newcrest Mining’s Cadia Valley operations in New South Wales with an AISC of $A168/oz, then Aurelia Metals’ Hera polymetallic mine in NSW ($A452/oz and followed by Evolution’s Mt Carlton mine in Queensland ($A493/oz)
Aurum said all these mines benefited from significant base metal by-products.
The lowest cost “gold only” operations were Kirkland Lake’s Fosterville mine in Victoria ($A613/oz), then Regis Resources’ Duketon North in Western Australia ($A661/oz) and Evolution Mining’s Cowal mine in NSW ($A852/oz).
Top gold producer for the quarter was again the Super Pit in Kalgoorlie for Newmont Mining and Barrick Gold with 196,000 oz, followed by Newcrest’s Cadia Valley in NSW (180,223 oz), then Newmont’s Boddington mine in WA (176,000 oz).
The average reported mill head/feed grade for the quarter was 3.65 g/t – based on 1.94 g/t for open pit and 5.81 g/t for underground.
Kirkland Lake’s Fosterville mine took the honours with the highest average feed grade of 21.5 g/t. followed by St Barbara’s Gwalia underground operation in WA at 10.7 g/t.
On Aurum’s list of AISC detailing companies, OceanaGold Corporation’s Waihi operations on New Zealand’s North Island was ranked ninth with an AISC of $A885/oz and a grade of 9.09 g/t. Production for the three months was 31,761/oz.
New Zealand’s only other major hard rock mining operation is OceanaGold’s Macraes project which has a large bulk mining open pit as well as higher grade underground mine below its big Frasers open pit.
This operation missed a ranking but in the December quarter had an operating margin of about $US200/oz, whereas some of the bottom rung operations in the Aurum report were in the red.
This included Blackham Resources at Wiluna in WA which on open pit and underground operations had an AISC of $A1,882/oz and subsequently underwent management and structural changes.
Wiluna is a major old mining camp where there is refractory and arsenic-laced ores which, in recent years, has proved to be a graveyard for some operators.