Gruyere joint venture partners Gold Road Resources and Gold Fields have successfully ramped up production at the gold mine near Laverton in Western Australia.
The Gruyere mill has completed 96 continuous hours of safe, steady-state operations, according to the project partners.
Over the period, 73,590 tonnes were processed at an average recovery of 95.8 per cent and an average grade of 1.17 grams per tonne gold, at a conservative rate of 725 tonnes per hour.
With the test completed, the site’s capacity will be ramped up to achieve high utilisation of the process plant to deliver nameplate capacity of 300,000 ounces per year.
Since mining commenced last month, a total of 3.4 million tonnes of ore has been mined at 0.83 grams per tonne gold for 90,700 contained ounces.
Operations have also included 1.7 million tonnes of run-of-mine (ROM) ore at a 1.09 grams per tonne gold, while the other half has been low-grade ore of 0.61 grams per tonne.
The low-grade ore has been used for “initial plant feed in commissioning, final construction and sheeting of the ROM stockpile platform, reclaim stockpile, and planned building of low-grade stockpiles for the long term.”
These results are close to the upper range of expectations. The expected production from the site remains at 75,000 to 100,000 ounces for 2019.
The operations original all-in sustaining costs (AISC) have been between $1050 and $1150 per ounce.
Gruyere’s cost guidance will be reviewed when commercial production is achieved –expected to be mid-way through the six to seven-month ramp-up period as previously stated.