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Changing the Face of Comminution—Insurmountable Hurdles
or Just Speed-Humps on the Journey?
Richard Bearman
Bear Rock Solutions Pty. Ltd.
ABSTRACT: Comminution has become somewhat of a Piñata for those looking to criticize mining and
processing. The sector is often subject to disparaging comments in relation to the energy and water footprint
of comminution, particularly as it relates to tumbling mills, use of steel media and the speed of change, but
is this fair? – where have we come from?, what are we doing? and what more can be done? Given the rapidity
that is demanded in relation to change, the mining sector does struggle, often due to the long life, capital
intensity and risk-averse nature of both mining companies and investors, but change is happening, albeit not
at the pace that some expect. The rise of compressive grinding, more efficient multi-stage systems, early waste
rejection and customized flowsheets, are all examples of changes in the core thinking, but deployment is slow.
Currently, we do not have all the answers, amongst others, we still need to improve our understanding of ore
and gangue behavior, how complexity is traded-off against non-traditional metrics, the role of non-mechanical
comminution and scalability of concepts. Many of the changes will be uncomfortable, but our sector can, and
has, responded to imperatives in the past and this gives us reason to believe we can continue to do so.
INTRODUCTION
The magnitude and use of energy and water in mining and
mineral processing systems has been a point of continu-
ing interest and concern, even before the acceleration in
interest as part of the focus on sustainability, emissions and
decarbonization.
Energy and the Future
The exact energy consumption in comminution has been
the subject of various estimates over the years. Work by
Daniel (2013) and more recently, Morrell (2023), take
detailed views of the entire mining industry and the con-
tribution from the hard rock sector. Morrell’s conclusion is
that comminution across the entire mining industry is just
over 1% of the global electrical energy consumption, whilst
the hard rock sector accounts for 0.6%.
In the same year, a report commissioned by Weir
(Engeco, 2023), found that across a wide range of com-
modities, comminution represents 25% of the total energy
consumption for an operation. At a global level, the report
states that, similar to Morrell, comminution equates to
approximately 1% of total worldwide energy consumption,
although no split to hard rock was provided by Engeco.
Energy consumption is not the full picture, as the gen-
eration of power is highly dependent upon the source and
also the efficiency of conversion between input materials
and the power outputted. In this regard, CO2 emissions are
a better point of comparison. Morrell, (2023) provides cal-
culations to demonstrate that CO2e emissions represents
0.16% and 0.27%, in hard rock and all mines, respectively,
as a percentage of global CO2e emissions.
Traditionally the focus was on reducing energy con-
sumption, as the provision of energy, regardless of source, is
Changing the Face of Comminution—Insurmountable Hurdles
or Just Speed-Humps on the Journey?
Richard Bearman
Bear Rock Solutions Pty. Ltd.
ABSTRACT: Comminution has become somewhat of a Piñata for those looking to criticize mining and
processing. The sector is often subject to disparaging comments in relation to the energy and water footprint
of comminution, particularly as it relates to tumbling mills, use of steel media and the speed of change, but
is this fair? – where have we come from?, what are we doing? and what more can be done? Given the rapidity
that is demanded in relation to change, the mining sector does struggle, often due to the long life, capital
intensity and risk-averse nature of both mining companies and investors, but change is happening, albeit not
at the pace that some expect. The rise of compressive grinding, more efficient multi-stage systems, early waste
rejection and customized flowsheets, are all examples of changes in the core thinking, but deployment is slow.
Currently, we do not have all the answers, amongst others, we still need to improve our understanding of ore
and gangue behavior, how complexity is traded-off against non-traditional metrics, the role of non-mechanical
comminution and scalability of concepts. Many of the changes will be uncomfortable, but our sector can, and
has, responded to imperatives in the past and this gives us reason to believe we can continue to do so.
INTRODUCTION
The magnitude and use of energy and water in mining and
mineral processing systems has been a point of continu-
ing interest and concern, even before the acceleration in
interest as part of the focus on sustainability, emissions and
decarbonization.
Energy and the Future
The exact energy consumption in comminution has been
the subject of various estimates over the years. Work by
Daniel (2013) and more recently, Morrell (2023), take
detailed views of the entire mining industry and the con-
tribution from the hard rock sector. Morrell’s conclusion is
that comminution across the entire mining industry is just
over 1% of the global electrical energy consumption, whilst
the hard rock sector accounts for 0.6%.
In the same year, a report commissioned by Weir
(Engeco, 2023), found that across a wide range of com-
modities, comminution represents 25% of the total energy
consumption for an operation. At a global level, the report
states that, similar to Morrell, comminution equates to
approximately 1% of total worldwide energy consumption,
although no split to hard rock was provided by Engeco.
Energy consumption is not the full picture, as the gen-
eration of power is highly dependent upon the source and
also the efficiency of conversion between input materials
and the power outputted. In this regard, CO2 emissions are
a better point of comparison. Morrell, (2023) provides cal-
culations to demonstrate that CO2e emissions represents
0.16% and 0.27%, in hard rock and all mines, respectively,
as a percentage of global CO2e emissions.
Traditionally the focus was on reducing energy con-
sumption, as the provision of energy, regardless of source, is