Modern Mining May 2018

GOLD

Impressive start-up by Mako

The newMako gold mine of Toro Gold in eastern Senegal is off to a good start, with most metrics ex- ceeding forecasts. Mill throughput for the first three months of operation, for example, was 540 kt at 2,34 g/t Au versus the budget of 460 kt at 2,49 g/t Au while average cash costs (including the ramp up phase) were US$746/oz versus the budget of US$984/oz, excluding royalties.

ore in the pit than expected leading to the likelihood that the trial would be based on non- representative softer ore. Management accordingly took the decision to utilise available lower grade hard/fresh ore for the trial which led to feed grades over the trial period of 1,7 g/t Au versus a budgeted grade for the period of 2,5 g/t Au. This led to a lower than planned average mill feed grade over the period, although this has been off- set by higher than expected mill throughput. Following the Performance Trial, the run of mine ore being fed to the mill is in line with budget forecasts. The Performance Trial was successfully completed during February 2018 and the con- struction team demobilised from the mine site shortly thereafter. Mining operations have been on-going since mid-2017 during the construction phase and have progressed well with good performance from the mining contractor African Mining Services Senegal SARL (AMSS). Grade control reconciliation to date, says Toro, shows good correlation with the forecast reserve model with grade. Given the topography of the deposit, the mining plan developed as part of the feasibil- ity study anticipated very limited weathered/ soft material to be mined with hard/fresh ore anticipated almost from the start of mining operations. During the development of the open pit, however, it became apparent that the weath- ering profile was more extensive than expected resulting in both the availability of free dig material and the use of lower powder factors for blasting – leading to improved operating costs through a reduction in drill and blast costs. A strategic review of the pit sequencing and access layout is underway with the aim of optimising operational flexibility and reducing operating costs through shorter haulage dis- tances. In the short term, there has been a focus on developing available ore benches over the first quarter with mining operations switching focus back to waste stripping during Q2 2018. To this end, ore tonnes mined are 10 % higher than budgeted over this period against waste

C onstruction of Mako, which is 90 % owned by Toro, a Guernsey- registered private gold exploration and development company, start- ed in August 2016 and the first gold pour took place on 26 January this year. Built within its budgeted capex of US$158 million, it will produce 136 koz/a of gold over six years of open-pit operation (although eight years of processing are planned). The ore is treated in a 1,8 Mt/a processing facility built by Lycopodium. Highlights over the period January to April 2018 include a successful transition to steady state operations at design levels of performance within a month of first gold pour; gold sales of 32 556 ounces at US$1 325/oz, slightly ahead of the 32 270 oz target; and metallurgical recover- ies of 94,8 % against the forecast of 91,3 %. Following on from the first gold pour at the end of January, the mine completed a series of operational trials over a 7-day continuous period to confirm operational performance of the metallurgical plant and ensure its ability to meet and maintain design parameters – the Performance Trial. The ore types at Mako are hard and abrasive and a key focus of the Performance Trial was to therefore ensure the comminution circuit could achieve the target grind size at forecast power consumption and circuit wear rates/consum- able use. Mining operations had encountered significantly more ‘weathered/soft’ full grade

The 1,8 Mt/a processing plant of the Mako gold mine (photo: Mako).

28  MODERN MINING  May 2018