Gold Road Resources and Gold Fields have reduced the annual production guidance of the Gruyere gold mine joint venture (JV) following a processing plant shutdown last week.
Gold Road stated that high bearing temperatures from the ball mill trunnion bearing caused misalignment to the feed end, resulting in unscheduled maintenance last week.
The ball mill was returned to service on September 30 and the site has progressively ramped up its mill throughput rates.
The JV partners have since cut their production guidance for the 12 months to June 2022 from between 260,000 to 300,000 ounces down to between 250,000 and 260,00 ounces
“Historically the ball mill has typically operated within a 12-13 megawatt power draw range and well below the 15 megawatt mill design,” Gold Road stated.
“Changes to the milling circuit configuration to increase power draw to the design capability of the ball mill forms part of the programme to lift process plant throughput rates towards a targeted 10 million tonnes per annum.
“Further alignment of the trunnion bearings will be completed during a planned shutdown in October when specialist technical personnel and equipment are available.”
The JV partners produced around 59,371 ounces of gold at Gruyere in the September quarter, which was still higher than the June quarter’s 53,132 ounces following a previous processing plant shutdown.
Gold Road’s three-year outlook aims to lift Gruyere’s production to 350,000 ounces by 2023 on a 100 per cent basis.
The company stated that production will increase in the December 2021 quarter due to higher grades and softer oxide ore, with quarterly production slated between 71,000 and 81,000 ounces.
Gold Road stated that all-in sustaining cost guidance for the 2021-22 financial year is under review due to the lower production guidance and will be provided in a quarterly report this month.
The Gruyere gold mine has an 11-year mine life with forecasted annual gold production of 300,000 ounces a year.
Gold Fields and Gold Road both have a 50 per cent interest in the Gruyere gold mine.