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Plant Design Comparison of Dry VRM Milling Plus Magnetic
Separation with AG and Ball Milling Plus Magnetic Separation
for Grange Resources’ Southdown Ore
Dean David
Wood
Dian Olwagen, Chris Stanton, Michael Everitt
Grange Resources
Carsten Gerold, Christian Schmitz, Stefan Baaken
Loesche GmbH
ABSTRACT: Loesche’s Vertical Roller Mill (VRM) has achieved superior pilot plant comminution outcomes
when treating Grange Resources’ Southdown ore. The Southdown magnetite deposit is a competent and abrasive
ore from southern Western Australia, situated in an area with poor access to power and water. From the mid-
2000s to the mid-2010s it was extensively evaluated using pilot scale conventional AG and ball milling coupled
with sequential tailings rejection by magnetic separation. Recent pilot VRM testing has demonstrated several
significant advantages over these wet milling circuits and also over dry milling alternatives, such as the use of
HPGRs in series.
An industrial VRM can accept open-circuit secondary crushed feed, make a single-pass P80 30 μm product,
operate dry, remove significant moisture from damp feed, selectively liberate hard minerals and produce an
ideally classified final product. VRMs are dust free in operation, the throughput and product size are readily
controllable, they are simple to maintain, and they utilize the same hydrostatic breakage mechanism that results
in HPGR power efficiency enhanced by a shear breakage component. When treating magnetite ores a grit frac-
tion, which is an internal dry classifier oversize stream, in case of the Southdown project, sized 1 mm +85 μm,
is intercepted and extracted for dry magnetic separation. Magnetic grits are returned to the VRM for additional
grinding and coarse dry non-magnetic grits are rejected to tailings. The final dry product is also suitable for
emerging fine dry magnetic separation that would further reduce water consumption. Another major advantage
of the technology is that the comminution and classification systems have a 100-year pedigree, having been
developed by Loesche in tandem. Industrial design is achieved with high confidence through Loesche’s extensive
testing and operating database.
Loesche’s “VRM /grit magnetic separation pilot plant” is a novel and unique facility that has demonstrated, in
the Southdown test work, to be up to 41% more energy efficient than pilot AG/Mag/Ball milling. In this paper
VRM milling is compared with wet milling and HPGR alternatives in areas such as test work, scaleup, CAPEX,
OPEX and operability. Special attention is given to the power and water savings, which are “game-changing”
for Southdown.
Plant Design Comparison of Dry VRM Milling Plus Magnetic
Separation with AG and Ball Milling Plus Magnetic Separation
for Grange Resources’ Southdown Ore
Dean David
Wood
Dian Olwagen, Chris Stanton, Michael Everitt
Grange Resources
Carsten Gerold, Christian Schmitz, Stefan Baaken
Loesche GmbH
ABSTRACT: Loesche’s Vertical Roller Mill (VRM) has achieved superior pilot plant comminution outcomes
when treating Grange Resources’ Southdown ore. The Southdown magnetite deposit is a competent and abrasive
ore from southern Western Australia, situated in an area with poor access to power and water. From the mid-
2000s to the mid-2010s it was extensively evaluated using pilot scale conventional AG and ball milling coupled
with sequential tailings rejection by magnetic separation. Recent pilot VRM testing has demonstrated several
significant advantages over these wet milling circuits and also over dry milling alternatives, such as the use of
HPGRs in series.
An industrial VRM can accept open-circuit secondary crushed feed, make a single-pass P80 30 μm product,
operate dry, remove significant moisture from damp feed, selectively liberate hard minerals and produce an
ideally classified final product. VRMs are dust free in operation, the throughput and product size are readily
controllable, they are simple to maintain, and they utilize the same hydrostatic breakage mechanism that results
in HPGR power efficiency enhanced by a shear breakage component. When treating magnetite ores a grit frac-
tion, which is an internal dry classifier oversize stream, in case of the Southdown project, sized 1 mm +85 μm,
is intercepted and extracted for dry magnetic separation. Magnetic grits are returned to the VRM for additional
grinding and coarse dry non-magnetic grits are rejected to tailings. The final dry product is also suitable for
emerging fine dry magnetic separation that would further reduce water consumption. Another major advantage
of the technology is that the comminution and classification systems have a 100-year pedigree, having been
developed by Loesche in tandem. Industrial design is achieved with high confidence through Loesche’s extensive
testing and operating database.
Loesche’s “VRM /grit magnetic separation pilot plant” is a novel and unique facility that has demonstrated, in
the Southdown test work, to be up to 41% more energy efficient than pilot AG/Mag/Ball milling. In this paper
VRM milling is compared with wet milling and HPGR alternatives in areas such as test work, scaleup, CAPEX,
OPEX and operability. Special attention is given to the power and water savings, which are “game-changing”
for Southdown.