3626 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
Ga). In this context, the iron formation at Mont Reed is
composed of fine to medium grained magnetite-hematite-
quartz units, associated with quartzite, marble, gneiss and
silicate-carbonate facies (Neal, 2000). The orebody has an
average grade of 30% Fe and extends over an area of about
2 × 3 km, with a thickness ranging from 60 to 100 m.
Geological interpretations describe Mont Reed as primarily
folded in an antiform shape that was later refolded orthog-
onally (Ibrango, 2013). In addition to iron oxides, most
of mineral assemblages of the iron formation consist of
quartz, Mg-Fe orthopyroxenes (enstatite–ferrosilite series),
Ca-clinopyroxenes to a lesser extent (eg diopside–heden-
bergite series) and carbonates (Klein, 1978).
One particularity of the Mont Reed deposit lies in the
fact that the ore contains both magnetite and hematite-rich
ores, with an overall magnetite to hematite ratio of about
2:1, together with the occurrence of a Mn-rich layer that
contaminates the orebody (Belissont, 2021). Furthermore,
the liberation degree of the particles is lower compared to
other deposits in the region. Additionally, the mineralogy
of the gangue is much more complex, characterised by the
presence of pyroxenes, carbonates, silicates, and amphiboles
(Mesquita et al, 2023). Hence, in addition to geological
and resource modelling, one key issue to make the deposit
exploitable is to find an optimal process route to concentrate
the ore, recovering both hematite /magnetite and avoiding
the presence of gangue minerals in the concentrate.
To address this issue, some studies have been carried out
to develop a feasible process route to concentrate the mate-
rial and produce a high-quality pellet feed (SiO2 1.8 %),
which can be fed into a direct reduction furnace (Lu et al.,
2015). Throughout the research process, a comprehensive
characterisation study was conducted using representative
samples from the Mont Reed deposit and showed a consid-
erable liberation of quartz particles below 1mm (Belissont,
2021). Additionally, a thorough series of bench-scale tests
was carried out to evaluate various methodologies for the
concentration of the ore and highlighted the potential of
using a pre-concentration stage in the route (Mesquita,
2021). Building upon the findings from these investiga-
tions, the preliminary flowsheet presented in Figure 3 was
developed.
The flowsheet comprises several stages, beginning with
a primary crushing step to adjust the run-of-mine (ROM)
size before proceeding to the SAG mill circuit (Rodrigues
et al., 2021). The main objective of the SAG circuit is to
liberate a portion of the gangue, producing then a product
with a P80 of 600 µm, which is then subjected to classifica-
tion at 150 µm. The oversize material from the screening
operation is directed to a pre-concentration stage, using
spirals (Sadeghi et al., 2016). Importantly, the classifica-
tion is performed before the pre-concentration stage to pre-
vent any loss of fine iron oxide particles within the spirals
(Mesquita et al, 2019). The concentrate obtained from the
Figure 2. Mont Reed preliminary flowsheet
Ga). In this context, the iron formation at Mont Reed is
composed of fine to medium grained magnetite-hematite-
quartz units, associated with quartzite, marble, gneiss and
silicate-carbonate facies (Neal, 2000). The orebody has an
average grade of 30% Fe and extends over an area of about
2 × 3 km, with a thickness ranging from 60 to 100 m.
Geological interpretations describe Mont Reed as primarily
folded in an antiform shape that was later refolded orthog-
onally (Ibrango, 2013). In addition to iron oxides, most
of mineral assemblages of the iron formation consist of
quartz, Mg-Fe orthopyroxenes (enstatite–ferrosilite series),
Ca-clinopyroxenes to a lesser extent (eg diopside–heden-
bergite series) and carbonates (Klein, 1978).
One particularity of the Mont Reed deposit lies in the
fact that the ore contains both magnetite and hematite-rich
ores, with an overall magnetite to hematite ratio of about
2:1, together with the occurrence of a Mn-rich layer that
contaminates the orebody (Belissont, 2021). Furthermore,
the liberation degree of the particles is lower compared to
other deposits in the region. Additionally, the mineralogy
of the gangue is much more complex, characterised by the
presence of pyroxenes, carbonates, silicates, and amphiboles
(Mesquita et al, 2023). Hence, in addition to geological
and resource modelling, one key issue to make the deposit
exploitable is to find an optimal process route to concentrate
the ore, recovering both hematite /magnetite and avoiding
the presence of gangue minerals in the concentrate.
To address this issue, some studies have been carried out
to develop a feasible process route to concentrate the mate-
rial and produce a high-quality pellet feed (SiO2 1.8 %),
which can be fed into a direct reduction furnace (Lu et al.,
2015). Throughout the research process, a comprehensive
characterisation study was conducted using representative
samples from the Mont Reed deposit and showed a consid-
erable liberation of quartz particles below 1mm (Belissont,
2021). Additionally, a thorough series of bench-scale tests
was carried out to evaluate various methodologies for the
concentration of the ore and highlighted the potential of
using a pre-concentration stage in the route (Mesquita,
2021). Building upon the findings from these investiga-
tions, the preliminary flowsheet presented in Figure 3 was
developed.
The flowsheet comprises several stages, beginning with
a primary crushing step to adjust the run-of-mine (ROM)
size before proceeding to the SAG mill circuit (Rodrigues
et al., 2021). The main objective of the SAG circuit is to
liberate a portion of the gangue, producing then a product
with a P80 of 600 µm, which is then subjected to classifica-
tion at 150 µm. The oversize material from the screening
operation is directed to a pre-concentration stage, using
spirals (Sadeghi et al., 2016). Importantly, the classifica-
tion is performed before the pre-concentration stage to pre-
vent any loss of fine iron oxide particles within the spirals
(Mesquita et al, 2019). The concentrate obtained from the
Figure 2. Mont Reed preliminary flowsheet