XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 3479
savings in CAPEX and OPEX by enabling the use of tail-
ings as a resource. Traditionally, the main dam walls and
significant sections of the auxiliary walls, are constructed
using quarried material. The dual classification feature of
the Cavex ® DE hydrocyclones results in the highly efficient
classification of the coarse tailings stream, meeting the
product specifications for use in dam construction.
Furthermore, the high efficiency of the equipment
allows it to perform effectively with a wide range of tailings
particle size characteristics, thus enabling resource-utilisa-
tion of the full spectrum from relatively fine to relatively
coarse tailings in this type of application.
The data presented in Table 2 shows that Cavex ® DE
hydrocyclones can operate effectively across a range of con-
ventional applications, processing both thickened and non-
thickened tailings, and still achieve the material properties
required for the construction of tailing walls. The permea-
bility of sands and the hydraulic capacity of the basal drains
are key properties for dam stability (Valenzuela, 2016). In
Chile the current practice for tailings dams is to set the
percentage of fines between 15% and 19% in general and
between 15% and 17% for taller dams (Valenzuela, 2016).
Particle size degradation during transport and the potential
for particle segregation when placed from tall dam walls
require a cycloned sand product with a fines content well
below 15%. In most current cyclone applications an under-
flow fines content of less than 9% –200 mesh is applied
(Bruton et al., 2023),(Newman et al., 2023). In traditional
sand dam construction 15% –200 mesh is commonly used
as design parameter (Castro et al., 2009), (Barrera et al.,
2011), (Valenzuela, 2016).
The operational parameters for each application vary
depending on the concentration of solids by weight, the
particle size distribution, the rheology of the slurry, and
other factors as required by the cut point for classifica-
tion and underflow solids concentration for dewatering.
Typically, Cavex ® DE hydrocyclones require a feed pres-
sure from 14 to 22 psi (1 to 1.5 bar) in operations with
fresh, non-thickened tailings, and in some operations with
thickened, water-diluted tailings. With thickened tailings,
a higher energy input is necessary for separation due to the
increased rheology, with operational pressures from 22 to
34 psi (1.5 to 2.3 bar).
An extensive knowledge base has been built from expe-
rience with industrial operations. This knowledge base
supports estimating the performance of the Cavex ® DE
classification technology in more complex applications
such as paste tailings and mine backfill. The technology has
also demonstrated versatility in other applications, ranging
from dewatering to slimes removal.(Lopez et al., 2015)
DISCRETE TAILINGS APPLICATION
Our development has categorized the use of Cavex ® DE
hydrocyclones into four discrete process flowsheets:
1. Cavex ® DE hydrocyclone combined with centri-
fuge equipment for dewatering.
2. Cavex ® DE hydrocyclone combined with a thick-
ener to recover water from the overflow stream.
3. Cavex ® DE hydrocyclone combined with dewater-
ing screens to produce stacking sands or sands with
low fines content.
4. Cavex ® DE hydrocyclone combined with reclas-
sification of sands to produce a fines-free product.
Flowsheets 1 and 2 focus on dewatering the tailings and
delivering a controlled, high-density paste product.
Flowsheets 3 and 4 optimize the water drainage capacity of
the classified product. A short description of each process
flow is presented below, including an indicative mass bal-
ance for each of the four alternatives, and standardized for
medium or large-scale copper mining operations.
Cavex® DE Hydrocyclone Combined with Centrifuge
Equipment for Dewatering
The traditional use of Cavex ® DE hydrocyclones, as shown
in the previous section, can be enhanced for operations
requiring rapid water recovery with high fines content by
incorporating a centrifugal decanter. The basic flowsheet
for this application is shown in Figure 3. This equipment
facilitates highly efficient water recovery from the process
for reuse. Depending on the operating conditions, this type
of circuit can achieve an overall water recovery of 78% with
a make-up 0.45 m3/t. This makes it a good alternative for
locations with limited access to water resources or high
evaporation rates from reservoirs.
Table 2. Measured operational data for Cavex® DE hydrocyclone in copper mine tailings processing
Tailings Feed Type Cw, %w/w F80, µm Mass Split, %
Fines (#–200)
Feed, %
Fines (#–200)
Sands, %
Fresh tailings 25–35 140–250 25–65 44–62 10–15
Thickened Tailings with dilution 45–52 160–250 25–50 44–58 12–15
Thickened Tailings 55–61 180–250 20–38 44–55 13–15
savings in CAPEX and OPEX by enabling the use of tail-
ings as a resource. Traditionally, the main dam walls and
significant sections of the auxiliary walls, are constructed
using quarried material. The dual classification feature of
the Cavex ® DE hydrocyclones results in the highly efficient
classification of the coarse tailings stream, meeting the
product specifications for use in dam construction.
Furthermore, the high efficiency of the equipment
allows it to perform effectively with a wide range of tailings
particle size characteristics, thus enabling resource-utilisa-
tion of the full spectrum from relatively fine to relatively
coarse tailings in this type of application.
The data presented in Table 2 shows that Cavex ® DE
hydrocyclones can operate effectively across a range of con-
ventional applications, processing both thickened and non-
thickened tailings, and still achieve the material properties
required for the construction of tailing walls. The permea-
bility of sands and the hydraulic capacity of the basal drains
are key properties for dam stability (Valenzuela, 2016). In
Chile the current practice for tailings dams is to set the
percentage of fines between 15% and 19% in general and
between 15% and 17% for taller dams (Valenzuela, 2016).
Particle size degradation during transport and the potential
for particle segregation when placed from tall dam walls
require a cycloned sand product with a fines content well
below 15%. In most current cyclone applications an under-
flow fines content of less than 9% –200 mesh is applied
(Bruton et al., 2023),(Newman et al., 2023). In traditional
sand dam construction 15% –200 mesh is commonly used
as design parameter (Castro et al., 2009), (Barrera et al.,
2011), (Valenzuela, 2016).
The operational parameters for each application vary
depending on the concentration of solids by weight, the
particle size distribution, the rheology of the slurry, and
other factors as required by the cut point for classifica-
tion and underflow solids concentration for dewatering.
Typically, Cavex ® DE hydrocyclones require a feed pres-
sure from 14 to 22 psi (1 to 1.5 bar) in operations with
fresh, non-thickened tailings, and in some operations with
thickened, water-diluted tailings. With thickened tailings,
a higher energy input is necessary for separation due to the
increased rheology, with operational pressures from 22 to
34 psi (1.5 to 2.3 bar).
An extensive knowledge base has been built from expe-
rience with industrial operations. This knowledge base
supports estimating the performance of the Cavex ® DE
classification technology in more complex applications
such as paste tailings and mine backfill. The technology has
also demonstrated versatility in other applications, ranging
from dewatering to slimes removal.(Lopez et al., 2015)
DISCRETE TAILINGS APPLICATION
Our development has categorized the use of Cavex ® DE
hydrocyclones into four discrete process flowsheets:
1. Cavex ® DE hydrocyclone combined with centri-
fuge equipment for dewatering.
2. Cavex ® DE hydrocyclone combined with a thick-
ener to recover water from the overflow stream.
3. Cavex ® DE hydrocyclone combined with dewater-
ing screens to produce stacking sands or sands with
low fines content.
4. Cavex ® DE hydrocyclone combined with reclas-
sification of sands to produce a fines-free product.
Flowsheets 1 and 2 focus on dewatering the tailings and
delivering a controlled, high-density paste product.
Flowsheets 3 and 4 optimize the water drainage capacity of
the classified product. A short description of each process
flow is presented below, including an indicative mass bal-
ance for each of the four alternatives, and standardized for
medium or large-scale copper mining operations.
Cavex® DE Hydrocyclone Combined with Centrifuge
Equipment for Dewatering
The traditional use of Cavex ® DE hydrocyclones, as shown
in the previous section, can be enhanced for operations
requiring rapid water recovery with high fines content by
incorporating a centrifugal decanter. The basic flowsheet
for this application is shown in Figure 3. This equipment
facilitates highly efficient water recovery from the process
for reuse. Depending on the operating conditions, this type
of circuit can achieve an overall water recovery of 78% with
a make-up 0.45 m3/t. This makes it a good alternative for
locations with limited access to water resources or high
evaporation rates from reservoirs.
Table 2. Measured operational data for Cavex® DE hydrocyclone in copper mine tailings processing
Tailings Feed Type Cw, %w/w F80, µm Mass Split, %
Fines (#–200)
Feed, %
Fines (#–200)
Sands, %
Fresh tailings 25–35 140–250 25–65 44–62 10–15
Thickened Tailings with dilution 45–52 160–250 25–50 44–58 12–15
Thickened Tailings 55–61 180–250 20–38 44–55 13–15