XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 197
The liberation efficacy of HPSA processing is significantly
influenced by the mineralogy of the feedstock, particularly
favoring materials with multi-modal hardness and surface-
exposed minerals over those with locked mineral. Desired
size reduction and mineral liberation can be further
achieved through process variable controls. These variables
include nozzle exit stream velocity, circuit residence time,
particle size distribution, slurry solids mass fraction, and
other factors that can affect either the collision probability
or fracture probability. The process enables more efficient
liberation at coarser particle sizes than traditional mills.
Studies from Disa Technologies Inc. (Disa) have shown fur-
ther advantages of HPSA including: (1) efficient concentra-
tion of target minerals earlier in the processing sequence,
(2) improved grade and/or recovery, and (3) reduced mate-
rial requiring downstream processing.
On-site and field applications are discussed in this
paper however, there have been lab studies including
chalcopyrite and molybdenite in Cu-Mo bulk sulfide con-
centrates (Harvey, 2023) and gold-bearing pyrite in cya-
nide-leach tailings (Antoniak, 2020). Results for Cu-Mo
suggested that product grades could be obtained with HPSA
and effectively eliminate some, if not all, of the regrind-
ing circuits. Likewise, for pyrite studies, results removed
oxidation products from the pyrite surface which better
enabled pyrite flotation thereby reducing reagent schedule
(Harvey, 2023). Furthermore, simulation and model verifi-
cation studies have been developed by Weaver et al. (2024)
directly related to future development and selective libera-
tion mechanisms of HPSA systems (Weaver, 2024).
HIGH-PRESSURE SLURRY ABLATION
BACKGROUND
HPSA processing found its first application in the remedia-
tion of abandoned uranium mining waste. Initial studies
led to HPSA currently being the only technology validated
by the United States Environmental Protection Agency
(US EPA) as a viable solution for treatment of abandoned
uranium mines (Tetra Tech &Disa Technologies, 2023).
This processing was done on site with batch units at aban-
doned uranium mine sites. The next steps for HPSA sys-
tem development were for continuous unit development
and improved performance and functionality of the sys-
tems. Next generation designs have been developed to
ensure modularity of HPSA units, such that they can be
used as stand-alone system or as a “plug and play” units
in the grinding/regrind stage of any processing circuit.
HPSA technology has the potential to replace some, or all
the grinding achieved by ball mills, rod mills, and attrition
scrubbers. Depending on processing requirements, HPSA
systems can compete with or outperform existing energy
intensive mills to reduce CAPEX, OPEX, and overall emis-
sions in processing circuits.
Both single jet, three phase flow (Weaver et al., 2024)
and opposed jet simulations with three phase flow (Weaver,
2024) using Computational Fluid Dynamic-Volume
of Fluid-Discrete Element Method (CFD-VOF-DEM)
simulations were investigated at the University of British
Columbia. In these studies, various design parameters for
converging nozzle designs were considered and verified
with particle tracking software. These trade studies were
conducted to develop relationships between design param-
eters and performance metrics like collision frequency or
particleparticle collision energies. In the cases tested, it
was found that increasing the nozzle-to-nozzle distance
increases the probability of collision due to spreading of
the jets in the collision region however, the impact energy
decreases as the spreading of the jet occurs reducing the
probability of fracture. Weaver specifically noted “the main
benefit of this machine is that it selectively breaks particles
of different sizes depending on the changes in operating
parameters” (Weaver 2024). Additionally, Weaver (2024)
determined effects that changing the nozzle angle of incli-
nation had on particle size and material properties as well
as subsequent impact on fluid flow, particle flow, and col-
lision behavior. In particular, Weaver (2024) used particle
tracing methodologies to monitor particles in the colliding
jets and was able to discern that particles of different size
classes behave differently in the collision region depending
on their Stokes number. Smaller particles in the jet have
low enough inertia that fluid flow in the jet collision area
can change their trajectories while larger particles deceler-
ate at a reduced rate, allowing for the particles to traverse
the collision boundary between the jets. The difference in
deceleration rates of the particles, creates lower velocities
for smaller particles, and thus lower collision energy for
fracture—demonstrating the mechanism for how the tech-
nology inherently prevents overgrinding of small particles.
In mineral processing, comminution is the reduction
of ore particle size for liberation of minerals, in prepara-
tion for separation and extraction in downstream processes.
Grinding is the most energy intensive step in most circuits
(Valery, 2016). Traditional comminution techniques such
as SAG mills, ball mills, and rod mills fracture the ore
by applying impact, compressive, and shear forces using
steel balls, rods, or other grinding media. Furthermore,
traditional grinding processes use randomness of impact
to accomplish fracture which inherently wastes potential
energy that could be used in fracture. Figure 1 illustrates
comminution fracture categorization detailed in Parapari et
The liberation efficacy of HPSA processing is significantly
influenced by the mineralogy of the feedstock, particularly
favoring materials with multi-modal hardness and surface-
exposed minerals over those with locked mineral. Desired
size reduction and mineral liberation can be further
achieved through process variable controls. These variables
include nozzle exit stream velocity, circuit residence time,
particle size distribution, slurry solids mass fraction, and
other factors that can affect either the collision probability
or fracture probability. The process enables more efficient
liberation at coarser particle sizes than traditional mills.
Studies from Disa Technologies Inc. (Disa) have shown fur-
ther advantages of HPSA including: (1) efficient concentra-
tion of target minerals earlier in the processing sequence,
(2) improved grade and/or recovery, and (3) reduced mate-
rial requiring downstream processing.
On-site and field applications are discussed in this
paper however, there have been lab studies including
chalcopyrite and molybdenite in Cu-Mo bulk sulfide con-
centrates (Harvey, 2023) and gold-bearing pyrite in cya-
nide-leach tailings (Antoniak, 2020). Results for Cu-Mo
suggested that product grades could be obtained with HPSA
and effectively eliminate some, if not all, of the regrind-
ing circuits. Likewise, for pyrite studies, results removed
oxidation products from the pyrite surface which better
enabled pyrite flotation thereby reducing reagent schedule
(Harvey, 2023). Furthermore, simulation and model verifi-
cation studies have been developed by Weaver et al. (2024)
directly related to future development and selective libera-
tion mechanisms of HPSA systems (Weaver, 2024).
HIGH-PRESSURE SLURRY ABLATION
BACKGROUND
HPSA processing found its first application in the remedia-
tion of abandoned uranium mining waste. Initial studies
led to HPSA currently being the only technology validated
by the United States Environmental Protection Agency
(US EPA) as a viable solution for treatment of abandoned
uranium mines (Tetra Tech &Disa Technologies, 2023).
This processing was done on site with batch units at aban-
doned uranium mine sites. The next steps for HPSA sys-
tem development were for continuous unit development
and improved performance and functionality of the sys-
tems. Next generation designs have been developed to
ensure modularity of HPSA units, such that they can be
used as stand-alone system or as a “plug and play” units
in the grinding/regrind stage of any processing circuit.
HPSA technology has the potential to replace some, or all
the grinding achieved by ball mills, rod mills, and attrition
scrubbers. Depending on processing requirements, HPSA
systems can compete with or outperform existing energy
intensive mills to reduce CAPEX, OPEX, and overall emis-
sions in processing circuits.
Both single jet, three phase flow (Weaver et al., 2024)
and opposed jet simulations with three phase flow (Weaver,
2024) using Computational Fluid Dynamic-Volume
of Fluid-Discrete Element Method (CFD-VOF-DEM)
simulations were investigated at the University of British
Columbia. In these studies, various design parameters for
converging nozzle designs were considered and verified
with particle tracking software. These trade studies were
conducted to develop relationships between design param-
eters and performance metrics like collision frequency or
particleparticle collision energies. In the cases tested, it
was found that increasing the nozzle-to-nozzle distance
increases the probability of collision due to spreading of
the jets in the collision region however, the impact energy
decreases as the spreading of the jet occurs reducing the
probability of fracture. Weaver specifically noted “the main
benefit of this machine is that it selectively breaks particles
of different sizes depending on the changes in operating
parameters” (Weaver 2024). Additionally, Weaver (2024)
determined effects that changing the nozzle angle of incli-
nation had on particle size and material properties as well
as subsequent impact on fluid flow, particle flow, and col-
lision behavior. In particular, Weaver (2024) used particle
tracing methodologies to monitor particles in the colliding
jets and was able to discern that particles of different size
classes behave differently in the collision region depending
on their Stokes number. Smaller particles in the jet have
low enough inertia that fluid flow in the jet collision area
can change their trajectories while larger particles deceler-
ate at a reduced rate, allowing for the particles to traverse
the collision boundary between the jets. The difference in
deceleration rates of the particles, creates lower velocities
for smaller particles, and thus lower collision energy for
fracture—demonstrating the mechanism for how the tech-
nology inherently prevents overgrinding of small particles.
In mineral processing, comminution is the reduction
of ore particle size for liberation of minerals, in prepara-
tion for separation and extraction in downstream processes.
Grinding is the most energy intensive step in most circuits
(Valery, 2016). Traditional comminution techniques such
as SAG mills, ball mills, and rod mills fracture the ore
by applying impact, compressive, and shear forces using
steel balls, rods, or other grinding media. Furthermore,
traditional grinding processes use randomness of impact
to accomplish fracture which inherently wastes potential
energy that could be used in fracture. Figure 1 illustrates
comminution fracture categorization detailed in Parapari et