A Change in Graphite Depressant to Improve the Recovery of Zinc at MMG Century Mine



Author: Roger Wynn, MMG Century

Co-Authors: Dr. Rolf Andreas Lauten, Pionera; Hans Liang, MMG Century and Nathan Stoitis, Pionera

Published in: 2014

Volume Title: 12th AusIMM Mill Operators’ Conference 2014

Wynn, R, Lauten, R A, Liang, H and  Stoitis, N, 2014. A change in graphite depressant to improve the recovery of  zinc at MMG Century mine, in Proceedings 12th AusIMM Mill Operators’ Conference 2014, pp 179–186 (The Australasian Institute of Mining and Metallurgy: Melbourne). 


At the Century mine in northwest Queensland MMG produces lead and zinc concentrates. The current production is close to 500,000 tons of Zinc per annum.  Graphite is the main gangue in the ore body and a substantial amount of chemicals are used to achieve acceptable depression of graphite and other gangue materials in the current operation.  In the future, it is anticipated that the content of graphite in the ore body will increase while the zinc grade will gradually drop. This scenario illustrates the importance of an optimised suite of flotation chemicals to maximise the grade and recovery. As an alternative to the current reagent suite where dextrin is used to depress graphite, lab testwork and subsequent plant trials where conducted with alternate depressants. These depressants facilitated both graphite depression and elevated zinc grades in the rougher concentrate. As an added benefit, it was also observed that the silica content in the zinc concentrate was reduced in the presence of the biopolymer selected for the plant trials. Results from both laboratory tests and plant trials will be discussed to illustrate how this change of reagent suite improved flotation yield at the MMG Century mine.


The whole article can be downloaded at: http://www.ausimm.com.au/publications/epublication.aspx?ID=16055