PERTH (miningweekly.com) – Australia-managed diversified junior Cleveland Mining has introduced a revised mine plan at its Premier gold joint venture project, in Brazil.

The company - which restarted operations at Premier in July after implementing cost reduction measures, including a 50% reduction in staff numbers - said  that it had taken a more conservative view of the mine’s ramp-up profile.

Cleveland has previously targeted production of some 7 000 oz a quarter from 2014, based on an average monthly production rate of 25 000 t/m of ore, with an average head grade of around 3.2 g/t gold, and assuming a 90% recovery rate. But the company had now made this its longer-term forecast and is instead planning to start processing at a rate of 15 000 t/m from Premier and expand this to 30 000 t/m once an additional ball mill was installed.

Cleveland explained that it had taken a more conservative view of the ramp-up profile, particularly in relation to further investment in the flotation circuit required to increase the gold recovery rate from the forecast 75% under the gravity and in-line leach reactor (ILR) circuit, up to the targeted 90%. While the investment appeared sound, the decision to add the flotation circuit was best made after alterations to the gravity circuit were bedded down and optimised, enabling a better understanding of the scope and scale of the flotation circuit required, the company said.

Under the new mine plan, an average quarterly production rate of around 2 870 oz was forecast, with production sourced mainly from the Metago and Pit 3 openpit mining areas.

Over the medium term, additional tonnes outside of the Metago and Pit 3 mine areas would be introduced into the operation, including higher head grade sourced from O Capitão.

The upgraded throughput rate, at a targeted head grade of 3 g/t and a recovery rate of 90% through the addition of flotation, would align with the longer-term forecast of 7 000 oz a quarter.

The revised mine plan was based on a reviewed mineral resource, which consisted of a resource estimate of 950 000 t, at 1.52 g/t gold for 46 400 oz, of which 18 900 oz was classified as indicated and 27 500 oz as inferred.