XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 3801
copper-gold mining (Seidel et al., 2006). In 1995, Cyprus
Sierrita of USA installed the first HPGR for copper ore
processing (L. G. Thompsen 1997). Cyprus introduced
HPGR as part of a plant modernization program intended
to reduce operational costs (OPEX) while increasing capac-
ity (L. Thompsen et al., 1996). This unit was decommis-
sioned in 1996 due to the ore’s abrasiveness overcoming
available wear protections (Patzelt et al., 2001). Taking les-
sons learned from Cyprus, sufficient improvements allowed
HPGR to be reapplied for copper in Peru at the Cerro
Verde in 2006 (Davaanyam 2015 Patzelt et al., 2001).
2006 proved to be a significant year as it saw the Cerro
Verde application, an upsurge in SAG conference technical
papers and steady growth in HPGR installations (Burchardt
&Mackert, 2019 Davaanyam 2015).
Meanwhile, HPGR saw its first application to iron ores
in 1997 based USA’s Cleveland Cliffs Empire Mine, for
gold in 2003 at USA based Lone Tree mine, and for plati-
num in 2004 at Potgietersrust of South Africa (Davaanyam
2015 Patzelt et al., 2006). In 2009, HPGR was first used
for heap leaching of gold at Goldfields Tarkwa Mine in
Ghana (Burchardt et al., 2011). This operation was consid-
ered the first operation to attempt to prove if HPGR can
achieve faster leaching rates and higher recoveries observed
in the laboratory (Burchardt et al., 2011).
By 2000 there were 45 HPGR installations for dia-
mond and iron operations (M. J. Daniel &Morley, 2010).
By 2010 the number of HPGR totaled 107 consisting of
35 diamond, 42 iron, and 30 split among copper, gold,
and platinum (M. J. Daniel &Morley, 2010). As of 2019,
evidence indicates that installations continued steadily
(Burchardt &Mackert, 2019 M. Daniel, 2007 M. J.
Daniel &Morley, 2010 van der Meer &Maphosa, 2012).
Identifying an exact number of current HPGR installations
has proven elusive.
HPGR’S ROLES IN COMMINUTION
HPGR’s were initially considered a potential tool for replac-
ing ball mills or as pebble crushers in Semi-Autogenous
Ball Mill Crusher (SABC) circuits (Burchardt &Mackert,
2019 Schönert 1988). Now, HPGR is primarily applied
as: (Burchardt et al., 2011 M. J. Daniel &Morley, 2010).
• Tertiary or quaternary crushing
• Pebble crushing
• Secondary and re-crushing for diamonds
• Heap leaching applications
The use of HPGR as tertiary crushing in hard rock was a
milestone for energy and wear cost reductions (Figure 3)
(Burchardt et al., 2011). Quaternary crushing of HPGR
can also allow coarsening of crushing product size reliv-
ing pressure if the crushers are a bottleneck (Burchardt &
Mackert, 2019). The unpredictability of greenfield SAG
pebble rates necessitates oversizing SAG pebble crushing.
Pebble crushing HPGR can be operationally controlled
through the grinding pressure and roll speed to compensate
for the unpredictably greenfield pebble crushing applica-
tions (Burchardt &Mackert, 2019).
Brownfield applications of HPGR are normally
aimed at increased production or reducing operating costs
(Klymowsky 2006). HPGR can improve brownfield plant
capacities or recoveries when increasing ore hardness affects
existing circuits (Burchardt &Mackert, 2019).
ADVANTAGES AND HURDLES TO HPGR
DEVELOPMENT
From HPGR’s inception its performance has been com-
pared to tumbling mills. Tumbling milling’s adaptable
and dominant role in comminution has created a wealth
of information for comparison to HPGR (Chandramohan
et al., 2023). The abundance of tradeoff studies highlights
Figure 3. A standard mineral processing circuit including potential HPGR roles
copper-gold mining (Seidel et al., 2006). In 1995, Cyprus
Sierrita of USA installed the first HPGR for copper ore
processing (L. G. Thompsen 1997). Cyprus introduced
HPGR as part of a plant modernization program intended
to reduce operational costs (OPEX) while increasing capac-
ity (L. Thompsen et al., 1996). This unit was decommis-
sioned in 1996 due to the ore’s abrasiveness overcoming
available wear protections (Patzelt et al., 2001). Taking les-
sons learned from Cyprus, sufficient improvements allowed
HPGR to be reapplied for copper in Peru at the Cerro
Verde in 2006 (Davaanyam 2015 Patzelt et al., 2001).
2006 proved to be a significant year as it saw the Cerro
Verde application, an upsurge in SAG conference technical
papers and steady growth in HPGR installations (Burchardt
&Mackert, 2019 Davaanyam 2015).
Meanwhile, HPGR saw its first application to iron ores
in 1997 based USA’s Cleveland Cliffs Empire Mine, for
gold in 2003 at USA based Lone Tree mine, and for plati-
num in 2004 at Potgietersrust of South Africa (Davaanyam
2015 Patzelt et al., 2006). In 2009, HPGR was first used
for heap leaching of gold at Goldfields Tarkwa Mine in
Ghana (Burchardt et al., 2011). This operation was consid-
ered the first operation to attempt to prove if HPGR can
achieve faster leaching rates and higher recoveries observed
in the laboratory (Burchardt et al., 2011).
By 2000 there were 45 HPGR installations for dia-
mond and iron operations (M. J. Daniel &Morley, 2010).
By 2010 the number of HPGR totaled 107 consisting of
35 diamond, 42 iron, and 30 split among copper, gold,
and platinum (M. J. Daniel &Morley, 2010). As of 2019,
evidence indicates that installations continued steadily
(Burchardt &Mackert, 2019 M. Daniel, 2007 M. J.
Daniel &Morley, 2010 van der Meer &Maphosa, 2012).
Identifying an exact number of current HPGR installations
has proven elusive.
HPGR’S ROLES IN COMMINUTION
HPGR’s were initially considered a potential tool for replac-
ing ball mills or as pebble crushers in Semi-Autogenous
Ball Mill Crusher (SABC) circuits (Burchardt &Mackert,
2019 Schönert 1988). Now, HPGR is primarily applied
as: (Burchardt et al., 2011 M. J. Daniel &Morley, 2010).
• Tertiary or quaternary crushing
• Pebble crushing
• Secondary and re-crushing for diamonds
• Heap leaching applications
The use of HPGR as tertiary crushing in hard rock was a
milestone for energy and wear cost reductions (Figure 3)
(Burchardt et al., 2011). Quaternary crushing of HPGR
can also allow coarsening of crushing product size reliv-
ing pressure if the crushers are a bottleneck (Burchardt &
Mackert, 2019). The unpredictability of greenfield SAG
pebble rates necessitates oversizing SAG pebble crushing.
Pebble crushing HPGR can be operationally controlled
through the grinding pressure and roll speed to compensate
for the unpredictably greenfield pebble crushing applica-
tions (Burchardt &Mackert, 2019).
Brownfield applications of HPGR are normally
aimed at increased production or reducing operating costs
(Klymowsky 2006). HPGR can improve brownfield plant
capacities or recoveries when increasing ore hardness affects
existing circuits (Burchardt &Mackert, 2019).
ADVANTAGES AND HURDLES TO HPGR
DEVELOPMENT
From HPGR’s inception its performance has been com-
pared to tumbling mills. Tumbling milling’s adaptable
and dominant role in comminution has created a wealth
of information for comparison to HPGR (Chandramohan
et al., 2023). The abundance of tradeoff studies highlights
Figure 3. A standard mineral processing circuit including potential HPGR roles