OPTIMISATION OF ASANKO’S OBOTAN SABC CIRCUIT TO ACHIEVE ‘PROJECT 5 MILLION’

R BRADFORD, W GIFT-AGBEY, E GROBLER, P MORGAN AND T VORSTER 

14^thAusIMM Mill Operators’ Conference, 29-31 August 2018, Brisbane, Australia

Africa

ABSTRACT

The Asanko Gold Mine in Ghana started processing ore from the Nkran pit in January 2016 at a production

nameplate of 3 Mt/a. The flowsheet is a conventional SAG, ball mill and pebble crusher (SABC) with gravity gold

and carbon-in-leach (CIL) recovery. The nameplate production was comfortably achieved within 3 months,

so much so, that it was clear the SABC circuit was capable of processing more than the downstream section

of the plant. Consequently, a program of de-bottlenecking was initiated to rectify volumetric capacity

constraints. This program was later referred to as ‘Project 5 Million’ (t/a) or P5M. Having completed the de-bottlenecking

exercise, it became evident that the SABC circuit could not reach 5 Mt/a solely on hard rock from

Nkran. The new challenge was therefore to increase the capacity of the milling circuit through a focused

comminution initiative that would address the following: geometallurgical treatment plan; upfront fragmentation

requirements; installation of feed and mill monitoring equipment; and integration of a knowledge-based control

strategy.

This paper takes the reader through the various measures implemented to increase the milling rates and to

create a stable/sustainable control philosophy. As a result of the implementation of advanced mill performance

monitoring technology (MillSlicer) and the collaboration between a team of experts in comminution, control and

operations, the Asanko Gold Mine process plant feed tonnage has successfully increased from 3 Mt/a to 5

Mt/a.

AUTHOR DETAILS

R BRADFORD (1), W GIFT-AGBEY (2), E GROBLER (3), P MORGAN (4) AND T VORSTER (5)

(1) FAusIMM, Consulting Metallurgist Executive, Asanko Gold, Perth. Email: This email address is being protected from spambots. You need JavaScript enabled to view it.

(2) Process Manager, Asanko Gold Accra, Ghana. Email: This email address is being protected from spambots. You need JavaScript enabled to view it.

(3) H.O.D. DRA Power Systems, DRA Global, Johannesburg. Email: This email address is being protected from spambots. You need JavaScript enabled to view it.

(4) Process Engineer - Comminution Consultant, DRA Global, Scotland. Email: This email address is being protected from spambots. You need JavaScript enabled to view it.

(5) Group Engineer, Asanko Gold, Johannesburg. Email: This email address is being protected from spambots. You need JavaScript enabled to view it.

ACKNOWLEDGEMENTS

CEEC acknowledges and thanks The Australian Institute of Mining and Metallurgy for organising the 14^thAusIMM Mill Operators’ Conference (MillOps 2018). 

Abstracts can be found at the MillOps 2018 website.