3623
The Importance of a Pre-Concentration Stage in a Low-Grade
Iron Ore Flowsheet
J. Mesquita
ArcelorMittal Global R&D, Maizières-lès-Metz, France
Université de Lorraine, CNRS, Laboratoire Lorrain de Chimie Moléculaire, Metz, France
Y. Foucaud
GeoRessources, Université de Lorraine, CNRS, Nancy, France
H. Turrer
ArcelorMittal Global R&D, Maizières-lès-Metz, France
M. Badawi
Université de Lorraine, CNRS, Laboratoire Lorrain de Chimie Moléculaire, Metz, France
ABSTRACT: The development of efficient flowsheets able to process low-grade ores is one of the main challenges
faced by the mining industry today. This type of ores obliges high processing plant throughput rates, which
would result in increased energy consumption and operational costs. In this scenario, pre-concentration appears
as a clever technological solution to prevent or minimize these problems through the preliminary discarding of
the liberated gangue, which would be treated in the plant without necessity. In this way, the present work aims
at evaluating the addition of a pre-concentration stage in the mineral processing route of a low-grade iron ore
and assess its benefits in the global process. During the study pilot-scale tests with different pre-concentration
circuit configurations were conducted, and the results showed that a single-stage pre-concentration circuit
effectively removed the free gangue from the material while minimizing iron losses. The chosen circuit achieved
a good balance between gangue removal and iron recovery, leading to a significant increase in the iron grade of
the pre-concentrate (from 32.11% to 39.55% Fe). During the testwork, 32% of the feed mass was removed,
discarding 60% of the silica contained in the original material. Additional Liberation analyses revealed the
effectiveness of the pre-concentration stage in diverting free particles of quartz to the tailings and retaining
most recoverable iron oxides in the concentrate. Estimated annual cost savings of 1.8 million USD are expected
based on planned plant production, energy costs, and specific energy requests for grinding. Overall, the study
underscores the importance of pre-concentration as a sustainable solution for treating low-grade ores in mining
business, addressing both economic and environmental considerations.
Keywords: pre-concentration, iron ore, spiral concentrators, energy savings

Previous Page Next Page

Extracted Text (may have errors)

3623
The Importance of a Pre-Concentration Stage in a Low-Grade
Iron Ore Flowsheet
J. Mesquita
ArcelorMittal Global R&D, Maizières-lès-Metz, France
Université de Lorraine, CNRS, Laboratoire Lorrain de Chimie Moléculaire, Metz, France
Y. Foucaud
GeoRessources, Université de Lorraine, CNRS, Nancy, France
H. Turrer
ArcelorMittal Global R&D, Maizières-lès-Metz, France
M. Badawi
Université de Lorraine, CNRS, Laboratoire Lorrain de Chimie Moléculaire, Metz, France
ABSTRACT: The development of efficient flowsheets able to process low-grade ores is one of the main challenges
faced by the mining industry today. This type of ores obliges high processing plant throughput rates, which
would result in increased energy consumption and operational costs. In this scenario, pre-concentration appears
as a clever technological solution to prevent or minimize these problems through the preliminary discarding of
the liberated gangue, which would be treated in the plant without necessity. In this way, the present work aims
at evaluating the addition of a pre-concentration stage in the mineral processing route of a low-grade iron ore
and assess its benefits in the global process. During the study pilot-scale tests with different pre-concentration
circuit configurations were conducted, and the results showed that a single-stage pre-concentration circuit
effectively removed the free gangue from the material while minimizing iron losses. The chosen circuit achieved
a good balance between gangue removal and iron recovery, leading to a significant increase in the iron grade of
the pre-concentrate (from 32.11% to 39.55% Fe). During the testwork, 32% of the feed mass was removed,
discarding 60% of the silica contained in the original material. Additional Liberation analyses revealed the
effectiveness of the pre-concentration stage in diverting free particles of quartz to the tailings and retaining
most recoverable iron oxides in the concentrate. Estimated annual cost savings of 1.8 million USD are expected
based on planned plant production, energy costs, and specific energy requests for grinding. Overall, the study
underscores the importance of pre-concentration as a sustainable solution for treating low-grade ores in mining
business, addressing both economic and environmental considerations.
Keywords: pre-concentration, iron ore, spiral concentrators, energy savings

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3624 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
INTRODUCTION
The effective administration of mineral resources represents
a crucial concern within contemporary development poli-
cies, manifesting itself as one of the main concerns of the
modern society (Smol et al., 2020). This imperative stems
from the recognition that even the most robust global
economies necessitate consistent and secure access to min-
eral resources to sustain perpetual growth and stable social
development (Gao et al., 2023).
Globally, there is a decline in metallic ore grades due
to the prioritized exploitation of richer reserves, leading to
their gradual depletion. Concurrently, the demand for pri-
mary metals derived from these ores is anticipated to rise,
notwithstanding augmented levels of dematerialization and
recycling (Table 1).
In this context, steel (and consequently iron ore) plays
a foundational role in modern society, serving by one side
as a cornerstone in multiple sectors, including construc-
tion, packaging, transportation, and infrastructure (Birat,
2020), and being responsible for intensive carbon emis-
sions in the other (Pardo and Moya, 2013). Addressing
sustainability concerns underscores the imperative to fulfil
these escalating demands while concurrently minimizing
resource consumption and mitigating environmental emis-
sions (Norgate and Jahanshahi, 2010).
Furthermore, the development of efficient flowsheets
able to process low-grade ores is one of the main challenges
faced by the mining industry today (Sousa et al., 2020).
This type of ores obliges high processing plant throughput
rates, which would result in increased energy consumption
and operational costs (Wills and Finch, 2016). This fact
holds immense significance for the project’s development,
considering that grinding operations are widely recognised
as energetically inefficient, accounting for approximately
34 to 44 per cent of the energy consumption in a mineral
processing plant (Esteves et al., 2021)
In this scenario, pre-concentration is a clever technolog-
ical solution to prevent or minimize the above-mentioned
problems before the most costly stages, more specifically
before grinding and concentration processes.(Sousa et al.,
2020). It consists of the preliminary discarding of the liber-
ated or partially liberated gangue with little or no metal of
interest, reducing the mass to be fed into the mill and in
subsequent operations (José Neto et al., 2019). This brings
a range of benefits for the mining business, as presented in
Table 2.
It worth to mention that the pre-concentration is highly
dependent on the pattern of gangue liberation and ore tex-
ture, which means that characterizations studies play a very
important role in the definition/optimization of these pro-
cesses (Sousa et al., 2020). That said, pre-concentration has
been achieved through consolidated technologies capable
of treating coarse particles, such as screens, dense medium
separators, jigs, spiral concentrators, sorters and magnetic
separators (José Neto et al., 2019). For iron ore operations,
gravity separation is sometimes followed by magnetic sepa-
ration to improve the grade of valuable minerals in mag-
netic concentrates when they are associated with magnetite
particles (Farrokhpay et al., 2019).
In this way, the present work aims at evaluating the
addition of a pre-concentration stage in the mineral pro-
cessing route of a low-grade iron ore from Mont Reed
deposit and assess it benefits in the global process.
The Mont Reed deposit is in the southern section of the
Labrador Trough (Greenville tectonic province), Québec,
Canada. the mining property was initially acquired by
Québec Cartier Mining (QCM -now ArcelorMittal) dur-
ing the 1960s and remains unexploited since (Québec
Cartier Mining Company, 1977) (Figure 1).
The Labrador Trough contains world-class
Palaeoproterozoic, Lake Superior-type, banded iron forma-
tions (BIFs, 1.88 Ga), that were weakly to intensely meta-
morphosed during the late Precambrian orogeny (ca. 1.0
Table 1. General information about common metals (Norgate and Jahanshahi, 2010)
Metal Economic Ore Grade (%w/w)
Reserves
(Mt of metal)
Production in 2006
(Mt/y)*
Years of Supply
†,‡
Iron/steel 30–60 79,000 858 92
Aluminium 27–29 4675 33 142
Copper 0.5–2 480 15.3 31
Lead 5–10 67 3.4 20
Zinc 10–30 220 10 22
Nickel 1.5–3 64 1.6 40
*Includes primary and secondary metal.
† Assumes consumption rate closely balanced to total production rate.
‡ Assumes no recycling.

Previous Page Next Page

Extracted Text (may have errors)

3624 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
INTRODUCTION
The effective administration of mineral resources represents
a crucial concern within contemporary development poli-
cies, manifesting itself as one of the main concerns of the
modern society (Smol et al., 2020). This imperative stems
from the recognition that even the most robust global
economies necessitate consistent and secure access to min-
eral resources to sustain perpetual growth and stable social
development (Gao et al., 2023).
Globally, there is a decline in metallic ore grades due
to the prioritized exploitation of richer reserves, leading to
their gradual depletion. Concurrently, the demand for pri-
mary metals derived from these ores is anticipated to rise,
notwithstanding augmented levels of dematerialization and
recycling (Table 1).
In this context, steel (and consequently iron ore) plays
a foundational role in modern society, serving by one side
as a cornerstone in multiple sectors, including construc-
tion, packaging, transportation, and infrastructure (Birat,
2020), and being responsible for intensive carbon emis-
sions in the other (Pardo and Moya, 2013). Addressing
sustainability concerns underscores the imperative to fulfil
these escalating demands while concurrently minimizing
resource consumption and mitigating environmental emis-
sions (Norgate and Jahanshahi, 2010).
Furthermore, the development of efficient flowsheets
able to process low-grade ores is one of the main challenges
faced by the mining industry today (Sousa et al., 2020).
This type of ores obliges high processing plant throughput
rates, which would result in increased energy consumption
and operational costs (Wills and Finch, 2016). This fact
holds immense significance for the project’s development,
considering that grinding operations are widely recognised
as energetically inefficient, accounting for approximately
34 to 44 per cent of the energy consumption in a mineral
processing plant (Esteves et al., 2021)
In this scenario, pre-concentration is a clever technolog-
ical solution to prevent or minimize the above-mentioned
problems before the most costly stages, more specifically
before grinding and concentration processes.(Sousa et al.,
2020). It consists of the preliminary discarding of the liber-
ated or partially liberated gangue with little or no metal of
interest, reducing the mass to be fed into the mill and in
subsequent operations (José Neto et al., 2019). This brings
a range of benefits for the mining business, as presented in
Table 2.
It worth to mention that the pre-concentration is highly
dependent on the pattern of gangue liberation and ore tex-
ture, which means that characterizations studies play a very
important role in the definition/optimization of these pro-
cesses (Sousa et al., 2020). That said, pre-concentration has
been achieved through consolidated technologies capable
of treating coarse particles, such as screens, dense medium
separators, jigs, spiral concentrators, sorters and magnetic
separators (José Neto et al., 2019). For iron ore operations,
gravity separation is sometimes followed by magnetic sepa-
ration to improve the grade of valuable minerals in mag-
netic concentrates when they are associated with magnetite
particles (Farrokhpay et al., 2019).
In this way, the present work aims at evaluating the
addition of a pre-concentration stage in the mineral pro-
cessing route of a low-grade iron ore from Mont Reed
deposit and assess it benefits in the global process.
The Mont Reed deposit is in the southern section of the
Labrador Trough (Greenville tectonic province), Québec,
Canada. the mining property was initially acquired by
Québec Cartier Mining (QCM -now ArcelorMittal) dur-
ing the 1960s and remains unexploited since (Québec
Cartier Mining Company, 1977) (Figure 1).
The Labrador Trough contains world-class
Palaeoproterozoic, Lake Superior-type, banded iron forma-
tions (BIFs, 1.88 Ga), that were weakly to intensely meta-
morphosed during the late Precambrian orogeny (ca. 1.0
Table 1. General information about common metals (Norgate and Jahanshahi, 2010)
Metal Economic Ore Grade (%w/w)
Reserves
(Mt of metal)
Production in 2006
(Mt/y)*
Years of Supply
†,‡
Iron/steel 30–60 79,000 858 92
Aluminium 27–29 4675 33 142
Copper 0.5–2 480 15.3 31
Lead 5–10 67 3.4 20
Zinc 10–30 220 10 22
Nickel 1.5–3 64 1.6 40
*Includes primary and secondary metal.
† Assumes consumption rate closely balanced to total production rate.
‡ Assumes no recycling.

3622 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
REFERENCES
Chandra, A. P. and A. R. Gerson (2009). “A review of the
fundamental studies of the copper activation mecha-
nisms for selective flotation of the sulfide minerals,
sphalerite and pyrite.” Adv Colloid Interface Sci 145
(1–2): 97–110.
Chen, J. and K. Chu, et al. (2017). “Systematic study of
the effect of particle density distribution on the flow
and performance of a dense medium cyclone.” Powder
technology 314: 510–523.
Chu, K. and J. Chen, et al. (2016). “Applicability of a
coarse-grained CFD–DEM model on dense medium
cyclone.” Minerals engineering 90: 43–54.
De Bakker, J. (2014). “Energy Use of Fine Grinding in
Mineral Processing.” Metallurgical and materials trans-
actions. E, Materials for energy systems 1 (1): 8–19.
Ejtemaei, M. and A. V. Nguyen (2017). “Characterisation
of sphalerite and pyrite surfaces activated by copper
sulphate.” Minerals engineering 100: 223–232.
Farjana, S. H. and N. Huda, et al. (2019). “A review on
the impact of mining and mineral processing industries
through life cycle assessment.” Journal of cleaner pro-
duction 231: 1200–1217.
Galvin, K. P. and A. M. Callen, et al. (2010). “Gravity sepa-
ration of coarse particles using the Reflux Classifier.”
Minerals engineering 23 (4): 339–349.
Leach, D. L. and R. D. Taylor, et al. (2010). “A deposit
model for Mississippi valley-type lead-zinc ores.”
Scientific Investigations Report.
Mohr, S. and D. Giurco, et al. (2018). “Global Projection of
Lead-Zinc Supply from Known Resources.” Resources
(Basel) 7 (1): 17.
Mudd, G. M. and S. M. Jowitt, et al. (2017). “The world’s
lead-zinc mineral resources scarcity, data, issues and
opportunities.” Ore geology reviews 80: 1160–1190.
Napier-Munn, T. (2018). “The dense medium cyclone—
past, present and future.” Minerals engineering 116:
107–113.
Nápoles Alberro, A. and H. A. González Rojas, et al. (2019).
“Model Based on an Effective Material-Removal Rate
to Evaluate Specific Energy Consumption in Grinding.”
Materials 12 (6): 939.
Robben, C. and J. de Korte, et al. (2014). “Experiences
in Dry Coarse Coal Separation Using X-Ray-
Transmission-Based Sorting.” International journal of
coal preparation and utilization 34 (3-4): 210–219.
Robben, C. and P. Condori, et al. (2020). “X-ray-
transmission based ore sorting at the San Rafael tin
mine.” Minerals engineering 145: 105870.
Syed, N. H. and J. E. Dickinson, et al. (2018). “Continuous,
dynamic and steady state simulation of the reflux clas-
sifier using a segregation-dispersion model.” Minerals
engineering 115: 53–67.
Yang, B. and X. Tong, et al. (2018). “Influence of the
Interaction between Sphalerite and Pyrite on the
Copper Activation of Sphalerite.” Minerals (Basel) 8
(1): 16.
ZHANG, X. and L. YANG, et al. (2011). “Estimation
of lead and zinc emissions from mineral exploitation
based on characteristics of lead/zinc deposits in China.”
Transactions of Nonferrous Metals Society of China 21
(11): 2513–2519.

Previous Page Next Page

Extracted Text (may have errors)

3622 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
REFERENCES
Chandra, A. P. and A. R. Gerson (2009). “A review of the
fundamental studies of the copper activation mecha-
nisms for selective flotation of the sulfide minerals,
sphalerite and pyrite.” Adv Colloid Interface Sci 145
(1–2): 97–110.
Chen, J. and K. Chu, et al. (2017). “Systematic study of
the effect of particle density distribution on the flow
and performance of a dense medium cyclone.” Powder
technology 314: 510–523.
Chu, K. and J. Chen, et al. (2016). “Applicability of a
coarse-grained CFD–DEM model on dense medium
cyclone.” Minerals engineering 90: 43–54.
De Bakker, J. (2014). “Energy Use of Fine Grinding in
Mineral Processing.” Metallurgical and materials trans-
actions. E, Materials for energy systems 1 (1): 8–19.
Ejtemaei, M. and A. V. Nguyen (2017). “Characterisation
of sphalerite and pyrite surfaces activated by copper
sulphate.” Minerals engineering 100: 223–232.
Farjana, S. H. and N. Huda, et al. (2019). “A review on
the impact of mining and mineral processing industries
through life cycle assessment.” Journal of cleaner pro-
duction 231: 1200–1217.
Galvin, K. P. and A. M. Callen, et al. (2010). “Gravity sepa-
ration of coarse particles using the Reflux Classifier.”
Minerals engineering 23 (4): 339–349.
Leach, D. L. and R. D. Taylor, et al. (2010). “A deposit
model for Mississippi valley-type lead-zinc ores.”
Scientific Investigations Report.
Mohr, S. and D. Giurco, et al. (2018). “Global Projection of
Lead-Zinc Supply from Known Resources.” Resources
(Basel) 7 (1): 17.
Mudd, G. M. and S. M. Jowitt, et al. (2017). “The world’s
lead-zinc mineral resources scarcity, data, issues and
opportunities.” Ore geology reviews 80: 1160–1190.
Napier-Munn, T. (2018). “The dense medium cyclone—
past, present and future.” Minerals engineering 116:
107–113.
Nápoles Alberro, A. and H. A. González Rojas, et al. (2019).
“Model Based on an Effective Material-Removal Rate
to Evaluate Specific Energy Consumption in Grinding.”
Materials 12 (6): 939.
Robben, C. and J. de Korte, et al. (2014). “Experiences
in Dry Coarse Coal Separation Using X-Ray-
Transmission-Based Sorting.” International journal of
coal preparation and utilization 34 (3-4): 210–219.
Robben, C. and P. Condori, et al. (2020). “X-ray-
transmission based ore sorting at the San Rafael tin
mine.” Minerals engineering 145: 105870.
Syed, N. H. and J. E. Dickinson, et al. (2018). “Continuous,
dynamic and steady state simulation of the reflux clas-
sifier using a segregation-dispersion model.” Minerals
engineering 115: 53–67.
Yang, B. and X. Tong, et al. (2018). “Influence of the
Interaction between Sphalerite and Pyrite on the
Copper Activation of Sphalerite.” Minerals (Basel) 8
(1): 16.
ZHANG, X. and L. YANG, et al. (2011). “Estimation
of lead and zinc emissions from mineral exploitation
based on characteristics of lead/zinc deposits in China.”
Transactions of Nonferrous Metals Society of China 21
(11): 2513–2519.