1528 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
composed of the raw Geopyörä breakage and sieving data,
especially the specific comminution energy (Ecs, kWh/t)
and the t10 (%),which are fundamental to calculate the
new Geopyörä Index.
GEOPYORA INDEX
The traditional DWI estimation process involves using the
Ecs and t10 points to perform a fit of the t10 curve, pre-
sented by equation 1, and derive the constants A and b.
Multiplication of these is the Axb rock hardness parameter
with correlations with the DWI (Doll 2024) and presented
by Equation 2.
DWI Axb
100SG =(2)
However, the curve fit process can be complex and
vary significantly depending on the fitting method chosen.
The difficulties increase even more in cases where there is a
mass limitation to compose the test sample. For this reason,
this work aims to present a direct way of calculating a new
breakage resistance parameter equivalent to the DWI, the
GPI, given by Equation 3.
GPI t
EcsSG
10
=(3)
It is important to emphasize that the possibility of
this direct calculation comes from the fact that the applied
breakage energy measured by the Geopyörä device is a
response rather than an input, since in traditional tests
the energy value is predefined through the gravitational
potential energy of a falling weight, while in the Geopyörä
test, even though the energy level is controlled by the gap
between the wheels, the energy measurement itself is a
proportional response to the mechanical properties of the
particles being broken. This feature allows Geopyörä to
produce energy measurements that can be accurately corre-
lated with various industry parameters (Bueno, de Almeida
and Powell, 2023). In this present work, the GPI is intro-
duced as an innovative parameter to directly describe rock
breakage resistance in kWh/m3.
The Geopyörä Index exhibits notable parallels with the
industry-standard parameter obtained through the SMC
test, from the Drop Weight Index as shown in Figure 4.
Due to its similarities with the DWI, the GPI demon-
strates a strong correlation with a mill’s power consump-
tion, mirroring the existing relationship observed with the
DWI. With this correlation, the GPI has the potential to
Table 1. Range of comminution parameters in the database
Axb
DWI,
kWh/m3
BWI,
kWh/t
Minimum 22.7 0.5 6.8
Mean 50.4 6.9 15.1
Maximum 436.6 13.0 26.1
0
5
10
15
20
0 5 10 15 20
GPI (kWh/m³)
Figure 4. DWI vs GPI plot
SMC
Test
DWI
(kWh/m³)
composed of the raw Geopyörä breakage and sieving data,
especially the specific comminution energy (Ecs, kWh/t)
and the t10 (%),which are fundamental to calculate the
new Geopyörä Index.
GEOPYORA INDEX
The traditional DWI estimation process involves using the
Ecs and t10 points to perform a fit of the t10 curve, pre-
sented by equation 1, and derive the constants A and b.
Multiplication of these is the Axb rock hardness parameter
with correlations with the DWI (Doll 2024) and presented
by Equation 2.
DWI Axb
100SG =(2)
However, the curve fit process can be complex and
vary significantly depending on the fitting method chosen.
The difficulties increase even more in cases where there is a
mass limitation to compose the test sample. For this reason,
this work aims to present a direct way of calculating a new
breakage resistance parameter equivalent to the DWI, the
GPI, given by Equation 3.
GPI t
EcsSG
10
=(3)
It is important to emphasize that the possibility of
this direct calculation comes from the fact that the applied
breakage energy measured by the Geopyörä device is a
response rather than an input, since in traditional tests
the energy value is predefined through the gravitational
potential energy of a falling weight, while in the Geopyörä
test, even though the energy level is controlled by the gap
between the wheels, the energy measurement itself is a
proportional response to the mechanical properties of the
particles being broken. This feature allows Geopyörä to
produce energy measurements that can be accurately corre-
lated with various industry parameters (Bueno, de Almeida
and Powell, 2023). In this present work, the GPI is intro-
duced as an innovative parameter to directly describe rock
breakage resistance in kWh/m3.
The Geopyörä Index exhibits notable parallels with the
industry-standard parameter obtained through the SMC
test, from the Drop Weight Index as shown in Figure 4.
Due to its similarities with the DWI, the GPI demon-
strates a strong correlation with a mill’s power consump-
tion, mirroring the existing relationship observed with the
DWI. With this correlation, the GPI has the potential to
Table 1. Range of comminution parameters in the database
Axb
DWI,
kWh/m3
BWI,
kWh/t
Minimum 22.7 0.5 6.8
Mean 50.4 6.9 15.1
Maximum 436.6 13.0 26.1
0
5
10
15
20
0 5 10 15 20
GPI (kWh/m³)
Figure 4. DWI vs GPI plot
SMC
Test
DWI
(kWh/m³)