Gold Fields is looking to change its mining method at Granny Smith so it can chase higher grade ore.
In a presentation at Denver Gold Forum, Gold Fields CEO Nick Holland said Granny Smith had been the star performer of the three mines the company bought from Barrick last year.
He said the mine’s output last quarter had totalled 85,000oz with all in costs of $US690/oz, The West Australian reported.
"It has surpassed all our expectations. It continues to get better at depth,” Holland said.
Holland said the mine currently used a room and pillar technique that only extracted 55 per cent of the orebody.
"When you're getting up to 8g or 9g (a tonne), we want all of it. So we are doing a study right now to see if we can move to past fill,” Holland explained.
South Africa’s Gold Fields also bought Darlot and Lawlers mines from Barrick last year in a deal worth $US300 million.
The assets will give Gold Fields extra WA yearly gold output of 452,000 ounces, 2.6 million ounces of reserves, and a further 1.9 million ounces in the resources section.
The company also owns the St Ives and Agnew mines in WA.