Low pH trial in the Ernest Henry Mining Copper Rougher Flotation Circuit

B. Kirkwood, J. Kinal, J. Siliezar, H. Sofatzis

Metallurgical Plant Design and Operating Strategies (MetPlant 2013), 15-17 July 2013, Perth WA

Ernest Henry Mining (EHM) is a copper, gold and magnetite mining and processing operation located 38 km north-east of Cloncurry in the Mount Isa-Cloncurry mineral district of north-west Queensland, Australia. The EHM ore body is an iron oxide copper gold deposit with an average grade of 1.1% copper, 0.5 g/tonne gold and 22% magnetite.

At the end of 2009, after a series of promising laboratory test work, EHM converted the ball mill media charge from forged steel to high chrome media. Laboratory test work also indicated that with the use of high chrome media, the pH was able to be reduced with no negative impact on plant performance. At high pH values (above 10.5), the forged media is passivated, so as the pH of the system drops the media corrosion rate increases and floods the system with the corrosion products, affecting flotation. As the high chrome media is much more inert, pH has less of an effect on copper flotation response.

This paper provides an overview of the effects of reducing the pH in the EHM copper rougher flotation circuit. The pH in the roughers was dropped from 10.6 to 9.6 to determine the impact on the rougher performance and the subsequent performance of the whole copper flotation circuit. It was found that there was a slightly increased improvement in copper recovery and no statistical change in either the rougher or final copper concentrate grades for copper and gold.

With the reduction in pH, there was a noticeable reduction in lime usage from 0.85 kg of lime per tonne of ore processed to 0.55 kg/tonne. This reduction in lime is equivalent to approximately $700,000 per annum at current production rates.

AUTHOR DETAILS

B. Kirkwood (1), J. Kinal (2), J. Siliezar (3), H. Sofatzis (4)

1. Plant Metallurgist, Xstrata Copper, Ernest Henry Mine, Cloncurry QLD 4824, This email address is being protected from spambots. You need JavaScript enabled to view it.
2. Metallurgy Manager, Magotteaux Australia, West Perth, WA 6005, This email address is being protected from spambots. You need JavaScript enabled to view it.
3. Metallurgy Superintendent, Glencore Copper, Ernest Henry Mine, Cloncurry QLD 4824, This email address is being protected from spambots. You need JavaScript enabled to view it.
4. Graduate Metallurgist, Glencore Copper, Ernest Henry Mine, Cloncurry QLD 4824, 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 Metallurgical Plant Design and Operating Strategies (MetPlant 2013). 

Abstracts can be found here.