XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 3805
of lower energy use while maintaining desired circuit func-
tionality (Gognon et al., 2022).
Operations have confirmed that feed moisture con-
tent to be a critical variable. Maintaining this moisture at
a well-defined range ensures an effective size reduction, as
well as steady operating conditions (Klymowsky 2006 van
der Meer &Maphosa, 2012). Pilot testing showed that
10% moisture was the maximum for smooth pilot HPGR
operation and screening (Gagnon et al., 2021). Industrial
examples of HPGR functioning with moisture conditions
exist. Diamonds ore treatment of a soft, sticky ores with
up to 16% moisture and iron ore pellet feed preparation
containing up to 12% moisture (Klymowsky 2003). The
necessitation of low moisture may also be partially advanta-
geous in arid regions (van de Vijfeijken et al., 2023).
Resilience of Soft Ductile Ores to Compression
Evidence has found that ore with soft, ductile, and caking
properties are the most resistive to the compressive break-
age benefits of HPGR (Davaanyam 2015 Klymowsky
2006). The effectiveness of compressive breakage is muted
by ductile and sticky materials because these material char-
acteristics will undergo plastic deformation before causing
compressive breakage (Semsari Parapari et al., 2020).
HPGR’s CAPEX and OPEX Balance
Tradeoff studies often show that the balance of selecting
HPGR or AG/SAG milling comes down the HPGR hav-
ing higher capital costs (CAPEX) with lower OPEX costs
(Amelunxen 2011 Burchardt et al., 2011 Klymowsky
2006 Lovatt et al., 2023 Rosario, 2017 van der Meer &
Maphosa, 2012). There may be misunderstanding about the
CAPEX costs of HGPR. Depending on site characteristics,
the number of necessary HPGR units may be less than AG/
SAG machines affecting the CAPEX balance (Burchardt et
al., 2011 Patzelt et al., 2001). Given that mineral process-
ing circuits are designed on the principle of cost efficiency
(Amelunxen 2011), each operation must use diligent test-
ing and circuit design procedures to determine what circuit
will work (Starkey et al., 2022).
FORWARD OUTLOOK: COMMINUTION
CIRCUITS OF THE FUTURE
Trade-off studies have shown HPGR’s applicability to
greenfield and brownfield debottlenecking circuit designs
(van de Vijfeijken et al., 2023). Industry members have
been working towards developing novel circuit designs to
adapt to the changing mineral processing environment.
These flowsheets reflect the understanding that comminu-
tion equipment does not operate in a vacuum. It is part
of the interlinked mineral processing system. The perfor-
mance of comminution will affect metal recovery (van de
Vijfeijken et al., 2023).
A collaborative work called ‘The flowsheet of the future’
showcases the opportunity for HPGR to be incorporated
into novel circuit designs (Figure 6) (van de Vijfeijken et
al., 2023). This system generates higher metal recoveries
with lower energy demands (van de Vijfeijken et al., 2023).
Microwave pre-treatment before tumbling grinding has
shown potential for microfracture formation allowing for
equivalent recoveries at larger float feed particle sizes which
support the direction of coarse particle flotation (Batchelor
et al., 2016 Tian et al., 2023). The success of microwave
pre-treatment to improve flotation indicates that the micro-
fracture tendency of HPGR may be an attractive option
for additional circuit designs which include coarse particle
Source: van de Vijfeijken et al., 2023
Figure 6. Interlinked mineral processing with HPGR (reprinted with permission)
of lower energy use while maintaining desired circuit func-
tionality (Gognon et al., 2022).
Operations have confirmed that feed moisture con-
tent to be a critical variable. Maintaining this moisture at
a well-defined range ensures an effective size reduction, as
well as steady operating conditions (Klymowsky 2006 van
der Meer &Maphosa, 2012). Pilot testing showed that
10% moisture was the maximum for smooth pilot HPGR
operation and screening (Gagnon et al., 2021). Industrial
examples of HPGR functioning with moisture conditions
exist. Diamonds ore treatment of a soft, sticky ores with
up to 16% moisture and iron ore pellet feed preparation
containing up to 12% moisture (Klymowsky 2003). The
necessitation of low moisture may also be partially advanta-
geous in arid regions (van de Vijfeijken et al., 2023).
Resilience of Soft Ductile Ores to Compression
Evidence has found that ore with soft, ductile, and caking
properties are the most resistive to the compressive break-
age benefits of HPGR (Davaanyam 2015 Klymowsky
2006). The effectiveness of compressive breakage is muted
by ductile and sticky materials because these material char-
acteristics will undergo plastic deformation before causing
compressive breakage (Semsari Parapari et al., 2020).
HPGR’s CAPEX and OPEX Balance
Tradeoff studies often show that the balance of selecting
HPGR or AG/SAG milling comes down the HPGR hav-
ing higher capital costs (CAPEX) with lower OPEX costs
(Amelunxen 2011 Burchardt et al., 2011 Klymowsky
2006 Lovatt et al., 2023 Rosario, 2017 van der Meer &
Maphosa, 2012). There may be misunderstanding about the
CAPEX costs of HGPR. Depending on site characteristics,
the number of necessary HPGR units may be less than AG/
SAG machines affecting the CAPEX balance (Burchardt et
al., 2011 Patzelt et al., 2001). Given that mineral process-
ing circuits are designed on the principle of cost efficiency
(Amelunxen 2011), each operation must use diligent test-
ing and circuit design procedures to determine what circuit
will work (Starkey et al., 2022).
FORWARD OUTLOOK: COMMINUTION
CIRCUITS OF THE FUTURE
Trade-off studies have shown HPGR’s applicability to
greenfield and brownfield debottlenecking circuit designs
(van de Vijfeijken et al., 2023). Industry members have
been working towards developing novel circuit designs to
adapt to the changing mineral processing environment.
These flowsheets reflect the understanding that comminu-
tion equipment does not operate in a vacuum. It is part
of the interlinked mineral processing system. The perfor-
mance of comminution will affect metal recovery (van de
Vijfeijken et al., 2023).
A collaborative work called ‘The flowsheet of the future’
showcases the opportunity for HPGR to be incorporated
into novel circuit designs (Figure 6) (van de Vijfeijken et
al., 2023). This system generates higher metal recoveries
with lower energy demands (van de Vijfeijken et al., 2023).
Microwave pre-treatment before tumbling grinding has
shown potential for microfracture formation allowing for
equivalent recoveries at larger float feed particle sizes which
support the direction of coarse particle flotation (Batchelor
et al., 2016 Tian et al., 2023). The success of microwave
pre-treatment to improve flotation indicates that the micro-
fracture tendency of HPGR may be an attractive option
for additional circuit designs which include coarse particle
Source: van de Vijfeijken et al., 2023
Figure 6. Interlinked mineral processing with HPGR (reprinted with permission)