FCF Minerals’ Runruno is a sulphide gold operation. Most of the gold is finely grained and disseminated in pyrite hence refractory to direct cyanidation. The Runruno process plant uses single stage SAG milling, gravity separation followed by intensive cyanide leaching of the gravity concentrate, flotation followed by bio-oxidation of the concentrate and cyanide leaching to extract the gold.
Since the beginning of 2019, the mill throughput has gradually increased and reached 26 per cent above the design capacity. Meanwhile, the overall plant gold recovery has also improved significantly, ie from 61 per cent in January to 85 per cent in September, by optimising the flotation operating conditions and eliminating excessive froth in the BiOX circuit.
Further optimisation and improvement projects are currently being developed, including retreatment of the InLine Leach Reactor (ILR) solid residue, commissioning of a variable speed drive for the SAG mill, additional flash flotation and gravity separation inside the grinding circuit, additional pneumatic flotation ahead of the existing conventional flotation bank, and additional air supply for the bioreactors. The aim is to increase Runruno gold production from 48.1 koz in 2018 and 68.6 koz in 2019, to 80 koz in 2020 and beyond.