Resolute Mining Ltd (ASX:RSG) (LON:RSG) is expecting its sulphide roaster at the Syama Gold Mine in Mali to be repaired and fully operational in about six weeks’ time.

The roaster was taken offline in early October due to the detection of a crack in the main external shell.

A detailed inspection of the main roaster chamber and structural assessment of the structural shell and related infrastructure has now been completed by Resolute’s technical team assisted by Outotec, the original designer of the Syama roaster.

Schematic diagram of the Syama sulphide roaster

The repair program is underway at Syama and the schedule forecasts completion of all required repair works in about six weeks’ time.

The roaster is expected to be fully operational in early to mid-December.

The preferred repair methodology is to install a secondary steel shell to the defective area where the crack has occurred.

While the roaster repairs are continuing Resolute is conducting a full structural and operational assessment of the roaster and all associated infrastructure and production handling systems.

All planned maintenance work will be advanced where possible.

This work will inform the existing plans for the normal biennial roaster shutdown scheduled during 2020 and is expected to enable a reduction to the planned number of days that the roaster will be offline for maintenance next year.

Syama processing plant

Mining activity at the new Syama Underground Mine is continuing during the roaster repair period.

The ramp-up of mining is progressing well with production ore now being trucked to the surface using Resolute’s fully automated haulage fleet.

This is a key commissioning milestone in the development of the world’s most advanced underground gold mine.

Mined ore tonnages increased to 422,517 tonnes in the September 2019 Quarter from 329,356 tonnes in the June 2019 Quarter.

In addition, caving is occurring to plan with grade profiles of ore mined reconciling to the mine model.

During the roaster repair period, mining activity will allow for the accumulation of ore stockpiles on the run-of-mine (ROM) pad with the expectation that up to 300,000 tonnes of ore will be readily available by the time the roaster is fully operational in December.

The availability of such a significant ROM pad ore stockpile, in addition to available concentrate stocks, will ensure maximum throughput operations are supported during the first quarter of 2020.

Gold production guidance remains unchanged

Resolute estimates the total cost of the roaster repairs at US$5 million.

This amount is expected to be offset by operational cost savings from not operating the roaster during the repair period.

The more important impact of the roaster downtime is lost gold production from the sulphide circuit.

Resolute intends to offset the lost production from the sulphide circuit by processing oxide material through the Syama sulphide circuit carbon in leach (CIL) infrastructure.

This plan entails processing historical stockpiled transitional ore mined from the Beta satellite open pit through the sulphide circuit mill and crusher and then bypassing the concentrator and roaster to feed this material directly into the sulphide circuit float tails leach circuit.

This will allow additional gold production from the Syama sulphide circuit during the period when the roaster is offline.

This additional production is expected to be further augmented by above budget performance from the Syama oxide circuit, the Ravenswood Gold Mine in Queensland, and Resolute’s new Mako Gold Mine in Senegal.

As a result, Resolute is not making any immediate change to its existing FY19 gold production guidance for the twelve months to 31 December 2019 of 400,000 ounces of gold.