Pilot Testing and Plant Design Comparison of Dry VRM Milling plus Magnetic Separation with AG and Ball Milling plus Magnetic Separation for Grange Resources' Southdown Ore

Pilot Testing and Plant Design Comparison of Dry VRM Milling plus Magnetic Separation with AG and Ball Milling plus Magnetic Separation for Grange Resources' Southdown Ore 

D David1, C Stanton2, D. Olwagen3, Dr C Gerold4, C Schmitz5, S Baaken6, M Everitt7 

1. FAusIMM CP(Met), Senior Consultant, Wood, Perth Western Australia
2. MAusIMM, Process Engineer, Grange Resources, Burnie Tasmania
3. Quality & Process Improvement Manager Grange Resources, Burnie Tasmania
4. Senior Manager, Ore and Minerals Technology, Loesche GmbH, Dusseldorf Germany
5. Senior Process Engineer, Ore and Minerals Technology, Loesche GmbH, Dusseldorf Germany
6. Head of Sales, Cement and Mining Div., Loesche GmbH, Dusseldorf Germany
7. MAusIMM, Geology Manager, Grange Resources, Perth Western Australia

Corresponding Author: Dean David, This email address is being protected from spambots. You need JavaScript enabled to view it.

*This paper was Submitted to Minerals Engineering Journal, 30/12/23

Abstract: 

Loesche’s Vertical Roller Mill (VRM) has achieved superior pilot plant comminution outcomes on hard Southdown Magnetite ore (Grange Resources, WA) compared to a conventional AG, magnetic separation and ball milling pilot circuit. VRMs utilise hydrostatic breakage to emulate HPGR power efficiency and can also achieve selective liberation. For magnetite ores, the dry VRM classifier oversize (“grit”, -3 mm+75 µm) is extracted continuously then magnetically separated. Magnetic grit is returned the VRM and non-magnetic grit is rejected to tailings.  The novel Loesche VRM pilot plant rejected 31 to 41% of feed mass as coarse non-mag grits while recovering between 95 and 97% of the magnetite to the 85 µm P80 product. VRM piloting was 33 to 36% more energy efficient than AG/Mag/Ball pilot milling and after scale up the VRM was 39 to 41% more efficient. There is strong evidence of enhanced selective liberation by VRM milling compared to tumbling milling. This paper will compare the flowsheets, outcomes, scale up difficulties and the industrial benefits of each method. 

Keywords: Southdown, Grange Resources, Loesche, Milling, comminution, VRM, AG Mill, Ball Mill, Magnetite, Magnetic separation, Power saving, Water saving