118 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
• Primary crushed material on a conveyor belt
• In-plant application at appropriate point (size-based,
particle-based, DMS, gravity etc.)
Scott and Amini (2020), examined the impacts of precon-
centration in terms of economic and environmental aspects
for twelve preconcentration options across six operations.
The data shown in Figure 6 shows an average of 6% reduc-
tion in energy intensity, an 8% reduction in emissions and
water intensity and an 11% reduction in steel intensity.
It should be noted that these values do not account for
embedded energy and related emissions.
The appropriate application of preconcentration can
undoubtedly offer direct benefit to downstream commi-
nution and if used in combination with improvements in
comminution equipment and circuits, the energy aspects
can be significantly amplified. A part of the preconcentra-
tion action, that is less beneficial, is that in the case of sul-
phide orebodies, the grade uplift will also see an uplift in
the grade of sulphide-associated minerals, i.e., pyrite. Such
concentration needs to be considered, due to the impact on
downstream corrosion and complications to the flotation
process.
Of all the system methods described above, the in-
situ extraction approach is the only one which effectively
removes comminution from the system. All the rest will still
require some level of comminution per production unit,
albeit, that the comminution demand may be decreased to
a certain extent.
COMMINUTION – CURRENT STATUS
AND OPTIONS
Within the mining and mineral processing context, it is
clear why comminution is a focus. The process of breaking
post-mining scale rock particles involves the application of
energy via equipment, with variable transmission efficiency
into actual useful breakage (Engeco, 2023).
Tumbling mills (SAG, ball, rod) are often the main
target for energy based criticism, as they do not transmit
energy into breakage in an efficient manner. Although a
focus of this paper, energy considerations cannot outweigh
operational practicality. Tumbling mills are work-horse of
the industry and they are able to handle a wide operational
envelope. One of the main considerations in moving away
from tumbling mills, is that the customization of commi-
nution circuits will often use equipment with much nar-
rower operational envelopes. As such, ore characterization
becomes even more critical for the design of effective cir-
cuits that can withstand feed variability.
Improvements may still be beneficially pursued in
direct relationship to tumbling mills, but many other
aspects of the comminution process can deliver improve-
ments, with some significantly outweighing what might be
achieved through fine-tuning tumbling mills themselves.
Some of the key areas that will contribute towards better
energy stewardship in comminution are listed below. It
is important to note that the delivery of the full benefit,
can only be realized through targeted system design and
Source: Scott and Amini 2020
Figure 6. Impact of preconcentration on key metrics
• Primary crushed material on a conveyor belt
• In-plant application at appropriate point (size-based,
particle-based, DMS, gravity etc.)
Scott and Amini (2020), examined the impacts of precon-
centration in terms of economic and environmental aspects
for twelve preconcentration options across six operations.
The data shown in Figure 6 shows an average of 6% reduc-
tion in energy intensity, an 8% reduction in emissions and
water intensity and an 11% reduction in steel intensity.
It should be noted that these values do not account for
embedded energy and related emissions.
The appropriate application of preconcentration can
undoubtedly offer direct benefit to downstream commi-
nution and if used in combination with improvements in
comminution equipment and circuits, the energy aspects
can be significantly amplified. A part of the preconcentra-
tion action, that is less beneficial, is that in the case of sul-
phide orebodies, the grade uplift will also see an uplift in
the grade of sulphide-associated minerals, i.e., pyrite. Such
concentration needs to be considered, due to the impact on
downstream corrosion and complications to the flotation
process.
Of all the system methods described above, the in-
situ extraction approach is the only one which effectively
removes comminution from the system. All the rest will still
require some level of comminution per production unit,
albeit, that the comminution demand may be decreased to
a certain extent.
COMMINUTION – CURRENT STATUS
AND OPTIONS
Within the mining and mineral processing context, it is
clear why comminution is a focus. The process of breaking
post-mining scale rock particles involves the application of
energy via equipment, with variable transmission efficiency
into actual useful breakage (Engeco, 2023).
Tumbling mills (SAG, ball, rod) are often the main
target for energy based criticism, as they do not transmit
energy into breakage in an efficient manner. Although a
focus of this paper, energy considerations cannot outweigh
operational practicality. Tumbling mills are work-horse of
the industry and they are able to handle a wide operational
envelope. One of the main considerations in moving away
from tumbling mills, is that the customization of commi-
nution circuits will often use equipment with much nar-
rower operational envelopes. As such, ore characterization
becomes even more critical for the design of effective cir-
cuits that can withstand feed variability.
Improvements may still be beneficially pursued in
direct relationship to tumbling mills, but many other
aspects of the comminution process can deliver improve-
ments, with some significantly outweighing what might be
achieved through fine-tuning tumbling mills themselves.
Some of the key areas that will contribute towards better
energy stewardship in comminution are listed below. It
is important to note that the delivery of the full benefit,
can only be realized through targeted system design and
Source: Scott and Amini 2020
Figure 6. Impact of preconcentration on key metrics