XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 123
When assembling a flowsheet, a sequential design pro-
cess is followed whereby various types of equipment are
selected and connected depending on the required process
design criteria. Existing equipment and known combina-
tions are the easiest to assemble, as it can effectively be a
“cookie-cutter” form of design, but this does not fit with
the development of innovative circuits.
It could be argued that many flowsheets have some
degree of innovation, but if the industry is to counter the
energy-based criticism, then the magnitude of the change
has to be far greater than just relatively minor improvements.
The only way that innovative solutions are considered,
is if an imperative exists that will drive the mining company
and its engineers to investigate further. The imperative cer-
tainly exists and the industry is now at, or close to, a point
where inaction is not an option and in fact such inaction
presents a greater risk than is perceived to exist is some of
the innovations.
HOW SHOULD COMMINUTION
CIRCUITS BE CONSIDERED?
Although the focus of this paper has been energy, the role
of water in comminution is equally and likely, more impor-
tant. In order to keep this paper as concise as possible, water
has not been specifically addressed, but in consideration
of future circuits it is a critical consideration (Luukkanen
et al., 2022). To take the industry towards newer circuit
designs, there are a range of key steps around energy and
water, including:
• Use detailed test work, precisely defined test meth-
ods and tools for the level of detail required.
• Conduct basic laboratory scale testing for early per-
formance indication and evaluation.
• Understand and challenge liberation size of both ore
and gangue minerals
• Ensure liberation size and distribution is understood,
including proportion of composite particles by size
and the options for Coarse Particle Liberation.
• Preconcentration evaluation as to where and when
to be used and impact on circuit configuration and
project economics.
• Early involvement in projects of key suppliers and
comminution SMEs
– Use known existing (ore characteristics) database,
containing proven references to provide basic
inputs for sizing equipment and OPEX (absorbed
power, wear parts) suitable for desktop comparison.
• Ensure test work is undertaken, not only to generate
test results, but also to demonstrate the practicalities
of operation and where possible access larger scale
vendor test equipment.
• Design the flowsheet using existing proven technolo-
gies in a new application and/or new combination in
the flowsheet
• Target maximum size reduction through compres-
sive grinding and focus on energy drivers in the cir-
cuit and avoidance of steel grinding media.
• Use proven tools, i.e., JKSimMet, SysCAD, IES,
to define the duty requirements and where avail-
able access vendor in-house equipment models and
simulations.
• Develop a comprehensive view and accurate com-
parison for all key metrics.
• Evaluate the benefits through scenario and sensitivity
analysis.
• Define the future-state for an operation using full
representation, i.e., digital twins
When specifically considering equipment and circuits for
dry processing, a range of areas need to be examined:
• Understand moisture content of Run of Mine (mini-
mum to maximum range and average) and site cli-
matic conditions (hot/dry vs cold/humid) and how
this could impact options for wet versus dry process-
ing and overall performance.
• Consider use of air classification to deliver fine prod-
ucts. The performance of classifiers is heavily depen-
dent upon moisture content and variability. Ensure
extensive testwork is undertaken on classifier effi-
ciency over the range of feed moisture.
• As multiple streams can be generated with the air
classifier, explore rejecting gangue through the air
classifier. The option will depend on sufficient differ-
ences in SG between minerals and will need to con-
sider differences is cross sectional area and impact on
drag forces.
• Evaluate circuit combinations with air classifiers,
sorting, magnetic separation and others. e.g., at the
air classifier middlings product stream.
• For full dry circuits review dust suppression and
material transportation of fines (fluidization).
CURRENT STATUS
Outside of the business level speed-humps, the key
aspects of scale, throughput and complexity have all been
highlighted.
In terms of gross scale, front-end comminution plants
exist which can match SAG mill applications. If the Cerro
Verde (5th largest copper mine in the World, based on
When assembling a flowsheet, a sequential design pro-
cess is followed whereby various types of equipment are
selected and connected depending on the required process
design criteria. Existing equipment and known combina-
tions are the easiest to assemble, as it can effectively be a
“cookie-cutter” form of design, but this does not fit with
the development of innovative circuits.
It could be argued that many flowsheets have some
degree of innovation, but if the industry is to counter the
energy-based criticism, then the magnitude of the change
has to be far greater than just relatively minor improvements.
The only way that innovative solutions are considered,
is if an imperative exists that will drive the mining company
and its engineers to investigate further. The imperative cer-
tainly exists and the industry is now at, or close to, a point
where inaction is not an option and in fact such inaction
presents a greater risk than is perceived to exist is some of
the innovations.
HOW SHOULD COMMINUTION
CIRCUITS BE CONSIDERED?
Although the focus of this paper has been energy, the role
of water in comminution is equally and likely, more impor-
tant. In order to keep this paper as concise as possible, water
has not been specifically addressed, but in consideration
of future circuits it is a critical consideration (Luukkanen
et al., 2022). To take the industry towards newer circuit
designs, there are a range of key steps around energy and
water, including:
• Use detailed test work, precisely defined test meth-
ods and tools for the level of detail required.
• Conduct basic laboratory scale testing for early per-
formance indication and evaluation.
• Understand and challenge liberation size of both ore
and gangue minerals
• Ensure liberation size and distribution is understood,
including proportion of composite particles by size
and the options for Coarse Particle Liberation.
• Preconcentration evaluation as to where and when
to be used and impact on circuit configuration and
project economics.
• Early involvement in projects of key suppliers and
comminution SMEs
– Use known existing (ore characteristics) database,
containing proven references to provide basic
inputs for sizing equipment and OPEX (absorbed
power, wear parts) suitable for desktop comparison.
• Ensure test work is undertaken, not only to generate
test results, but also to demonstrate the practicalities
of operation and where possible access larger scale
vendor test equipment.
• Design the flowsheet using existing proven technolo-
gies in a new application and/or new combination in
the flowsheet
• Target maximum size reduction through compres-
sive grinding and focus on energy drivers in the cir-
cuit and avoidance of steel grinding media.
• Use proven tools, i.e., JKSimMet, SysCAD, IES,
to define the duty requirements and where avail-
able access vendor in-house equipment models and
simulations.
• Develop a comprehensive view and accurate com-
parison for all key metrics.
• Evaluate the benefits through scenario and sensitivity
analysis.
• Define the future-state for an operation using full
representation, i.e., digital twins
When specifically considering equipment and circuits for
dry processing, a range of areas need to be examined:
• Understand moisture content of Run of Mine (mini-
mum to maximum range and average) and site cli-
matic conditions (hot/dry vs cold/humid) and how
this could impact options for wet versus dry process-
ing and overall performance.
• Consider use of air classification to deliver fine prod-
ucts. The performance of classifiers is heavily depen-
dent upon moisture content and variability. Ensure
extensive testwork is undertaken on classifier effi-
ciency over the range of feed moisture.
• As multiple streams can be generated with the air
classifier, explore rejecting gangue through the air
classifier. The option will depend on sufficient differ-
ences in SG between minerals and will need to con-
sider differences is cross sectional area and impact on
drag forces.
• Evaluate circuit combinations with air classifiers,
sorting, magnetic separation and others. e.g., at the
air classifier middlings product stream.
• For full dry circuits review dust suppression and
material transportation of fines (fluidization).
CURRENT STATUS
Outside of the business level speed-humps, the key
aspects of scale, throughput and complexity have all been
highlighted.
In terms of gross scale, front-end comminution plants
exist which can match SAG mill applications. If the Cerro
Verde (5th largest copper mine in the World, based on