COMMINUTION & CRUSHING
Nielsen. “There is no point having the most efficient equipment in the world if
it cannot be continuously operated at its most efficient,” he said
The HIGmill also contributes to efficient circuit design by carrying out
internal classification during operation. “Fine particles preferentially flow
upwards through the charge, while coarser particles are driven to the high
intensity grinding zones nearer to the circumference of the mill body,” Nielsen
explained. “This means only a scalping classifier, or even no classifier, is
required while minimising overgrinding, all while reducing the required
pumping capacity for the circuit.”
Outotec has designed the GrindForce™ rotor, meanwhile, to minimise
shear forces at the surface of the rotor, while encouraging high and evenly
distributed shear forces in the charge. This maximises grinding efficiency
while minimising wear on the rotors, Nielsen said.
The HIGmill is also available with the world's highest installed power in
fine grinding technology, according to the company. “For large projects, with
resulting high grinding power requirements, this means that fewer units are
required, reducing plant complexity and footprint,” Nielsen added.
Water balance
The HIGmill is set to play a role in one of the more talked about projects
currently under development.
Jointly owned by Fortescue Metals Group subsidiary FMG Magnetite Pty Ltd
and Formosa Steel IB, the Iron Bridge project, in Western Australia, is notable
for a few reasons.
First, it holds Australia’s largest JORC compliant magnetite resource.
Second, it is a multi-billion-dollar investment project being built at a time
when there is a dearth of new mine developments. Third, and most important
for this discussion, it will use a dry crushing and grinding circuit.
Fortescue says the innovative process design, including the use of this dry
crushing and grinding circuit, will deliver an industry-leading energy efficient
operation with globally competitive capital intensity and operating costs.
A pilot project to verify the Iron Bridge design involved processing 1 Mt of
ore through a full-scale HPGR and air classifier over a 12-month period to
produce a 67% Fe, low impurity concentrate product, according to Fortescue.
The pilot plant verified the wet magnetite processing flowsheet in close
collaboration with key equipment manufacturers, with the demo plant proving
the metallurgical and cost benefits of early waste rejection by using full-scale
dry processing equipment commonly seen in other industries, the miner said.
Extensive data was collected to support the design of the full-scale 22 Mt/y
(wet) ore processing facility, with Fortescue adding that the expected cost and
energy savings “are significant in relation to other existing magnetite
operations”.
The flowsheet shows primary crushing, followed by secondary crushing
into HPGRs (for tertiary crushing) before dry screening, dry separation and air
classification/HPGR primary grinding take place. It is only after these
activities that process water collected from this last step is reintroduced to
take the material through the last grinding and separation stages.
Weir is set to provide Iron Bridge with a range of equipment including
Enduron HPGRs and GEHO ® pumps, which, it says, will reduce energy
consumption and wet tailings waste by more than 30% compared with
traditional mining technologies.
Outotec’s scope, meanwhile, includes the design and delivery of 10
HIGmills, as well as installation and commissioning and site services to
support Iron Bridge with site operation and maintenance.
Both OEMs agree their respective Iron Bridge orders are representative of a
growing trend in the industry.
Dierx said: “The partnership between FMG and Weir has not gone
unnoticed in the industry and we are receiving a substantial amount of
enquiries about this exciting combination of HPGRs and dry air classification
in mining applications.”
In Australia and Latin America, specifically, new deposits are frequently
Grind down your
maintenance costs
Köppern roller presses have been proven successful
throughout the world in plants specializing in the cost-
saving high pressure comminution of various ores like
iron, copper, gold, diamond, molybdenum and lithium ore.
The Köppern Hybridur® tires feature an extremely
wear-resistant surface that provides enhanced roller
protection when grinding abrasive ores.
Köppern – Quality made in Germany.
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State of the art HPGRs and wear protection
Process technology know-how
High plant availability
Low maintenance cost
Pilot HPGR testing capabilities in Australia, Canada,
Germany and Russia
For further information please contact
[email protected]
www.koeppern.de
APRIL 2020 | International Mining 21