1
25-103
Crushing and Grinding Circuit Availability: Why Is It Important
in Design, and How Can We Increase It Cost-Effectively?
Rajiv Chandramohan
Ausenco, Vancouver BC
Greg Lane
Ausenco, Brisbane QLD
Phil Dakin
Ausenco, Brisbane QLD
John Lo Grande
Ausenco, Brisbane QLD
ABSTRACT
Crushing and grinding circuit availability is a critical design
factor defining the installed equipment selection and the
process buffers required to maintain throughput during
maintenance. The comminution circuit typically accounts
for a process plant’s largest capital expenditure and energy
use. Effective process and equipment selection and layout
optimization are crucial steps when combining the objec-
tives of cost-effective design and high circuit availability
in operation. This paper outlines fit-for-purpose design
principles for optimizing process flow, eliminating standby
equipment and reducing buffer residence time whilst
improving maintainability and operability.
Keywords: Comminution, cost-effective design, energy
efficient design, circuit availability, utilisation, optimisation
STATEMENTS AND DECLARATIONS
All authors are employees of Ausenco, an engineering con-
sultancy that works with the world’s leading mining and
mineral processing companies. This study’s analysis was
completed after all client-funded work was completed.
Data from this manuscript were presented at the
MINEXCHANGE 2025 SME Annual Conference &
Expo, February 23–26, 2025, held in Denver, Colorado.
INTRODUCTION
The comminution circuit is a key component of the min-
eral processing flowsheet. Comminution is the process
of size reduction that increases the liberation of valuable
minerals from gangue minerals. It is well known that com-
minution is a high energy consumer in a typical mineral
processing flowsheet, accounting for approximately 40%
of total power consumption (Chandramohan et al., 2023).
Therefore, selecting the correct flowsheet and equipment
is essential to achieve the desired annual throughput at the
target energy consumption.
Two broad factors drive the selection of preferred com-
minution flowsheet and equipment selection:
• Ore characteristics, for example, competency, hard-
ness, feed size distribution from the mine and pres-
ence of clays
• Target throughput rate, instantaneous and
life-of-mine.
The preferred flowsheet is defined by its value to the
project. Optimizing ‘value’ is essential for long-term project
success, seeking funding from investors, and building share-
holder confidence. The flowsheet selection is driven by:
• The capital cost required to build the project, impact-
ing on the overall net present value
• The operating costs, including
– the reliability of the circuit as it impacts mainte-
nance requirements and associated costs and
– energy efficiency and impact on greenhouse
emissions
Lane et al. (2008) and Lane and Dickie (2009) discuss
the link between design, optimizing the footprint, bulk-
material quantities (concrete, steel, pining, cable, etc.) and
capital cost for mineral processing plants. They defined
a smart and experienced team as one of the key require-
ments for good flowsheet design focused on adding value,
25-103
Crushing and Grinding Circuit Availability: Why Is It Important
in Design, and How Can We Increase It Cost-Effectively?
Rajiv Chandramohan
Ausenco, Vancouver BC
Greg Lane
Ausenco, Brisbane QLD
Phil Dakin
Ausenco, Brisbane QLD
John Lo Grande
Ausenco, Brisbane QLD
ABSTRACT
Crushing and grinding circuit availability is a critical design
factor defining the installed equipment selection and the
process buffers required to maintain throughput during
maintenance. The comminution circuit typically accounts
for a process plant’s largest capital expenditure and energy
use. Effective process and equipment selection and layout
optimization are crucial steps when combining the objec-
tives of cost-effective design and high circuit availability
in operation. This paper outlines fit-for-purpose design
principles for optimizing process flow, eliminating standby
equipment and reducing buffer residence time whilst
improving maintainability and operability.
Keywords: Comminution, cost-effective design, energy
efficient design, circuit availability, utilisation, optimisation
STATEMENTS AND DECLARATIONS
All authors are employees of Ausenco, an engineering con-
sultancy that works with the world’s leading mining and
mineral processing companies. This study’s analysis was
completed after all client-funded work was completed.
Data from this manuscript were presented at the
MINEXCHANGE 2025 SME Annual Conference &
Expo, February 23–26, 2025, held in Denver, Colorado.
INTRODUCTION
The comminution circuit is a key component of the min-
eral processing flowsheet. Comminution is the process
of size reduction that increases the liberation of valuable
minerals from gangue minerals. It is well known that com-
minution is a high energy consumer in a typical mineral
processing flowsheet, accounting for approximately 40%
of total power consumption (Chandramohan et al., 2023).
Therefore, selecting the correct flowsheet and equipment
is essential to achieve the desired annual throughput at the
target energy consumption.
Two broad factors drive the selection of preferred com-
minution flowsheet and equipment selection:
• Ore characteristics, for example, competency, hard-
ness, feed size distribution from the mine and pres-
ence of clays
• Target throughput rate, instantaneous and
life-of-mine.
The preferred flowsheet is defined by its value to the
project. Optimizing ‘value’ is essential for long-term project
success, seeking funding from investors, and building share-
holder confidence. The flowsheet selection is driven by:
• The capital cost required to build the project, impact-
ing on the overall net present value
• The operating costs, including
– the reliability of the circuit as it impacts mainte-
nance requirements and associated costs and
– energy efficiency and impact on greenhouse
emissions
Lane et al. (2008) and Lane and Dickie (2009) discuss
the link between design, optimizing the footprint, bulk-
material quantities (concrete, steel, pining, cable, etc.) and
capital cost for mineral processing plants. They defined
a smart and experienced team as one of the key require-
ments for good flowsheet design focused on adding value,