3802 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
that the development of HPGR is a by-product of the bal-
ance between HPGR benefits and developmental hurdles
(Tbl. 1). The potential of HPGR’s advantages to address
industry’s financial, environmental, and political pressures
created an investment incentive to overcome HPGR’s ini-
tial hurdles (Baawuah et al., 2020 Napier-Munn 2015).
ADVANTAGES OF HPGR
HPGR’s compressive loading mechanism is the source
of HPGR’s prominent advantages (Saramak et al., 2010
Semsari Parapari et al., 2020). Effective energy transfer
results in more energy being used for particle breakage and
reduces losses in the forms of noise and heat (Saramak et
al., 2010).
Energy Efficient Particle Breakage
The prominent HPGR advantage over AG/SAG milling is
energy savings. The sources of these energy savings are the
comparatively lesser amount of energy needed to achieve
the same particle breakage and energy savings for down-
stream processes (Davaanyam 2015 Patzelt et al., 2001
Seidel et al., 2006). HPGR’s compressive loading circum-
vents tumbling milling’s energy expense of lifting materials
for breakage (van de Vijfeijken et al., 2023). The amount
of energy savings in hard rock are site specific (McIvor
1997). Tradeoff studies show that potential savings in com-
minution circuit energy can range from 5 to 40% when an
HPGR can be installed (Gagnon et al., 2021 Saramak et
al., 2010 Seidel et al., 2006). Specifically, when compared
to ball milling 40 to 60% energy efficiency increases have
been recorded (Burchardt et al., 2011).
High Fines Generation and Microfracture Formation
High fines generation combined with microfracture forma-
tion via compressive loading leads to follow-up comminu-
tion throughput increases and energy savings by reducing
the competence of HPGR’s product particles (Klymowsky
2006 van der Meer &Maphosa, 2012). HPGR product
contains a high content of fines which themselves may be
highly fissured (McIvor 1997). Simulation studies have
shown that the HPGR product has the potential of increas-
ing the grinding capacity of the ball mills by 25% when
HPGR replaces installed tertiary cone crushing (Klymowsky
2003). The larger fines content of HPGR has potential to
increase downstream ball milling throughput by 30–50%
(Klymowsky 2006). At Los Colorados iron operation of
Chile, ball millings after HPGR saw a 27 to 44% increased
capacity and reduced ball milling energy (van der Meer &
Maphosa, 2012). The Nurkazgan of Kazakhstan copper
mine saw reduction in ball milling energy (van der Meer &
Maphosa, 2012).
Concentration Recovery Improvements
Compared to conventional crushing, HPGR comminution
improves metal recoveries by increasing mineral liberation.
Increased liberation is ideal for creating surface area and
activating the material for downstream processing such as
leaching (McIvor 1997). Copper leaching after HPGR com-
minution has shown 60% faster leach kinetics and between
2 to 10% increased recovery (Baum &Ausburn, 2011) and
Zinc leaching has shown potential for 10 to 15% improved
recovery with HPGR (Ghorbani et al., 2013). Laboratory
testing of Gold showed HPGR’s microfracture and high
Table 1. A summary of the hurdles and advantages for HPGR
Primary Advantages Secondary Advantages Hurdles
Energy efficient particle breakage Process stability Lack of experienced personnel
Microfracture formation causing
downstream processing benefits
Greater time availability Roll liner wear leading to significant
downtime
Higher generations of fines Fast start-up to full production Lack of reliable feasibility scale test
for mine planning
Simplified operation with fewer
operating parameters
Requirement of low moisture
content for processing
Savings in grinding media steel costs Processing of ductile and sticky ores
High pebble recycles rates High capital costs
Superior handling of low head grades
Low mill footprint requirement
Higher than predicted throughput
capabilities
Source: Amelunxen 2011 Baawuah et al., 2020 Davaanyam 2015 Klymowsky 2003, 2006 Morrell 2022
Saramak et al., 2010
that the development of HPGR is a by-product of the bal-
ance between HPGR benefits and developmental hurdles
(Tbl. 1). The potential of HPGR’s advantages to address
industry’s financial, environmental, and political pressures
created an investment incentive to overcome HPGR’s ini-
tial hurdles (Baawuah et al., 2020 Napier-Munn 2015).
ADVANTAGES OF HPGR
HPGR’s compressive loading mechanism is the source
of HPGR’s prominent advantages (Saramak et al., 2010
Semsari Parapari et al., 2020). Effective energy transfer
results in more energy being used for particle breakage and
reduces losses in the forms of noise and heat (Saramak et
al., 2010).
Energy Efficient Particle Breakage
The prominent HPGR advantage over AG/SAG milling is
energy savings. The sources of these energy savings are the
comparatively lesser amount of energy needed to achieve
the same particle breakage and energy savings for down-
stream processes (Davaanyam 2015 Patzelt et al., 2001
Seidel et al., 2006). HPGR’s compressive loading circum-
vents tumbling milling’s energy expense of lifting materials
for breakage (van de Vijfeijken et al., 2023). The amount
of energy savings in hard rock are site specific (McIvor
1997). Tradeoff studies show that potential savings in com-
minution circuit energy can range from 5 to 40% when an
HPGR can be installed (Gagnon et al., 2021 Saramak et
al., 2010 Seidel et al., 2006). Specifically, when compared
to ball milling 40 to 60% energy efficiency increases have
been recorded (Burchardt et al., 2011).
High Fines Generation and Microfracture Formation
High fines generation combined with microfracture forma-
tion via compressive loading leads to follow-up comminu-
tion throughput increases and energy savings by reducing
the competence of HPGR’s product particles (Klymowsky
2006 van der Meer &Maphosa, 2012). HPGR product
contains a high content of fines which themselves may be
highly fissured (McIvor 1997). Simulation studies have
shown that the HPGR product has the potential of increas-
ing the grinding capacity of the ball mills by 25% when
HPGR replaces installed tertiary cone crushing (Klymowsky
2003). The larger fines content of HPGR has potential to
increase downstream ball milling throughput by 30–50%
(Klymowsky 2006). At Los Colorados iron operation of
Chile, ball millings after HPGR saw a 27 to 44% increased
capacity and reduced ball milling energy (van der Meer &
Maphosa, 2012). The Nurkazgan of Kazakhstan copper
mine saw reduction in ball milling energy (van der Meer &
Maphosa, 2012).
Concentration Recovery Improvements
Compared to conventional crushing, HPGR comminution
improves metal recoveries by increasing mineral liberation.
Increased liberation is ideal for creating surface area and
activating the material for downstream processing such as
leaching (McIvor 1997). Copper leaching after HPGR com-
minution has shown 60% faster leach kinetics and between
2 to 10% increased recovery (Baum &Ausburn, 2011) and
Zinc leaching has shown potential for 10 to 15% improved
recovery with HPGR (Ghorbani et al., 2013). Laboratory
testing of Gold showed HPGR’s microfracture and high
Table 1. A summary of the hurdles and advantages for HPGR
Primary Advantages Secondary Advantages Hurdles
Energy efficient particle breakage Process stability Lack of experienced personnel
Microfracture formation causing
downstream processing benefits
Greater time availability Roll liner wear leading to significant
downtime
Higher generations of fines Fast start-up to full production Lack of reliable feasibility scale test
for mine planning
Simplified operation with fewer
operating parameters
Requirement of low moisture
content for processing
Savings in grinding media steel costs Processing of ductile and sticky ores
High pebble recycles rates High capital costs
Superior handling of low head grades
Low mill footprint requirement
Higher than predicted throughput
capabilities
Source: Amelunxen 2011 Baawuah et al., 2020 Davaanyam 2015 Klymowsky 2003, 2006 Morrell 2022
Saramak et al., 2010