Rock: Ore Processability Program
Program Leader – Malcolm Powell
Biography
From a physics background, Malcolm worked at Mintek then established the comminution research and
consulting groups at the University of Cape Town. He has since led the comminution research at the
JKMRC of the University of Queensland for 9 years and is director of the Anglo American Centre for
Sustainable Comminution. Malcolm collaborates extensively, with close compatriots on 5 continents
forming the Global Comminution Collaborative (GCC) providing a comprehensive worldwide research
team. He aims to link fundamental research into applied outputs through the development of
mechanistically correct but practical and robust process models. Malcolm has conducted applied
surveying and site optimisation studies on over 60 plants worldwide. His interests cover liner design,
SAG mill modelling and control, the unified comminution model (UCM), ore characterisation for multicomponent modelling, and Flexible circuits - to utilise today’s equipment while enabling the uptake of
tomorrows technology. These are published in over 150 articles.
Malcolm’s research vision is of integrated total process simulation as a tool for innovation – linking
geology, mining, energy and size reduction, gangue rejection and recovery into flexible process design
and process optimisation.
A central aim is development of flexible circuits - “FlexiCircuits leverage ore variability to maximise
resource utilisation”. The focus of flexible circuits is to investigate processing options that provide extra
capacity through sophistication rather than scale. This requires a combination of smart ore
characterisation, economic modelling and innovative processing plant design. Flexible mineral
processing circuits can respond to variations in feed characteristics (competence, size distribution, grade
and deleterious components) and processing requirements by varying the processing route in order to
maximise recovery within energy usage limitations. The application is via utilising today’s equipment
while enabling the uptake of tomorrow’s technology.
Program Aims
The Ore Processability program is focussed on the link between the intrinsic primary rock properties and
the processing outcomes when the rock is milled and treated. By focussing on the primary rock properties
of ores, their strength, mineral association and texture; a minimal number of strength and fragmentation
tests will be developed to describe the response of the ore particles to all the fragmentation and separation
processes. The resultant distribution of particle properties, based on mineral combinations, provides the
primary input information to any recovery process, plus all process streams such as tailings and waste
rock. The complex particle-based mineral structure information is carried mathematically by a mineral
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liberation model. Additionally, major processing costs including energy and water form a key part of the
valuation process.
Ore processing responses are not an ore characteristic, they are a combination of properties of the particles
and the specific equipment and environment that the particles are subjected to, e.g. mill throughput is
dependent on the blasting, transport, pre-treatment route of the rock in addition to the way the mill is
operated, so throughput can vary considerably for a given original block of rock in the ore body.
Accurate valuation of an ore deposit and to underpin investment and design decisions in developing ore
resources requires sound prediction of the processing amenability. The projects within the program
develop tools and knowledge that support mining and processing decisions in a manner that responds to
changes in ore-property and economic factors. Processing options can be evaluated with respect to
throughput, recovery, concentrate grade, processing energy, water treatment, tailings and waste
requirements. Applying on-line and rapid sensing to measure the minerals and textures of rock, will
provide the same primary properties to assess process control options in both the planning and live
operation of processing plants.
Research Focus Areas
The projects within the program span across the value chain in the areas of geology and geometallurgy,
mineralogical characterisation, process mineralogy, core logging and sensing technologies, ore strength
characterisation, fundamentals of rock breakage, texture and liberation modelling, and integrated process
knowledge. Strong collaborative linkages are envisaged with other SMI programs include the modelling
capabilities of the Processing program, mine planning and economic analysis within the BRC and tailings
management expertise within CMLR.
Impact
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Rationalised and consistent set of rock strength tests that can be applied to core and bulk samples
Predict the end products direct from core tests
Input to ore body processing modelling – a step up from traditional block modelling
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Linking sensing data for process control
Methods
Build a consistent approach to ore characterisation based on an understanding of the primary rock
properties, such that the measures provide the key information that can be used to describe the rock
characteristics relevant to mining and mineral processing. The processing responses are then calculated
on the fly at each point in the process. The key tools are Mineralogy, Physical characterisation, rapid
sensing, ore body modelling, and min planning.
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