DRA Global recently implemented an Advanced Milling Control System, using the MillSlicer instrument, on the Asanko gold mine in Ghana.

Asanko is a large scale, multi-pit asset located on the Asankrangwa belt in Ghana. Built in 2015 by DRA Global, ahead of schedule and within budget, first gold was poured in January 2016 and commercial production commenced in April 2016. The mine is now owned 50:50 by Asanko Gold Mining and Gold Fields.

DRA said: “Operations at Asanko prioritise efficiencies, with minimal downtime. Unplanned or forced mill stoppages and breakdowns can often lead to costly setbacks for overall mine operations.

The DRA Global technical processing specialists collaborated closely with the Asanko owner’s team to develop a control system solution that is able to produce real time reporting and enable the mill operators to better optimise the milling process.”

Val Coetzee, DRA’s Senior Vice President Process, said: “This MillSlicer Control instrument provides accurate signals via a number of strategically positioned vibration sensors that are used by DRA’s comminution and control specialists to develop bespoke control systems, specific to an operation. The programme allows for accurate mill charge toe-angle measurement and real time polar plot determination, which is used in the customised control system.”

The milling control system, which was commissioned by DRA in August 2018, uses propriety “rule-based algorithms” assisting the mine’s operation with superior control, maximising energy efficiency and ensuring continual optimal mill performance despite any changes in mine fragmentation or ore type variances, according to DRA.

Coetzee said: “DRA is able to provide remote operational support, data analysis and reporting to assist clients in reducing liner damage, media consumption and ensure that mill operators efficiently maximise throughput at all times.

“This MillSlicer hardware and the DRA Advanced Control System, in conjunction with a number of other initiatives relating to open circuit modifications, use of cameras and feed blending, have successfully contributed to the performance excellence of the Asanko processing plant in recent months.”

Russell Bradford, SVP Metallurgy at Asanko, said: “The MillSlicer hardware has enabled the Asanko team to optimise the mill’s performance by ensuring we always have the right blend of ore at the right tonnages in the mill. Since this technology was implemented, the Asanko processing plant has consistently delivered above its 5 Mt/y design rate.”

The Asanko mine is a 50:50 joint venture between Asanko Gold Mining and Gold Fields managed and operated by Aasnko. In 2018, the mine is targeting 200,000-220,000 oz of gold at an all-in sustaining cost of $1,050-$1,150/oz.