XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 3625
Table 2. Benefits of pre-concentration (adapted from José Neto et al., 2019)
Benefits Cause
Reducing energy
consumption/emissions
per ton of metal
produced
With early gangue rejection, there is a reduction in the mass fed into the mill, therefore energy is not
spent grinding material that is not of interest, thus reducing the required power. Furthermore, usually
gangue material is of a higher work index (WI) than that of the ore and as such, once it is discarded, the
specific consumption of the grinding circuit decreases.
Increasing tailings dam
life
When applied in the earlier stages of the process, a smaller volume of gangue is processed consequently,
the quantity of fine tailings generated that must be disposed of in a tailings dam is reduced.
Reusing wate /tailings As the tailings from pre-concentration is coarse and easily dewatered, it can be used, among others, for
paving roads, or filling galleries (backfill), and depending on its characteristics, it can be sold as a by-
product (e.g., gravel, sand, etc), thereby generating profit.
Reducing water
consumption
There is less mass to be slurried /treated resulting in less water consumption.
Increasing mine life By rejecting part of the gangue, the mine cut-off grade decreases, which allows the exploitation of
marginal ores and, consequently, there is an expansion of the reserves.
Positive impact on
flotation
Pre-concentration allows metal recovery improvements and eliminates fluctuations in the grade of the
flotation feed. In such a case, reagent consumption can be optimized, and the circuit can be simplified
through a possible reduction in the usage of cleaner and/or scavenger operations.
Positive impact on the
thickening
Reduction of the thickening unit capacity demand and flocculant consumption, particularly in the
tailings, which has been reduced.
Increasing the
production
When applied in the waste, the feed throughput of the plant is lower but offers a better grade. Thus, it is
possible to produce the same amount of metal at lower feed rates, obtaining a margin for an increase in
production without requiring expansion of the capacity of the grinding and concentration circuits.
Figure 1. Mont Reed location (ArcelorMittal assets in red -Ibrango, 2013)
Table 2. Benefits of pre-concentration (adapted from José Neto et al., 2019)
Benefits Cause
Reducing energy
consumption/emissions
per ton of metal
produced
With early gangue rejection, there is a reduction in the mass fed into the mill, therefore energy is not
spent grinding material that is not of interest, thus reducing the required power. Furthermore, usually
gangue material is of a higher work index (WI) than that of the ore and as such, once it is discarded, the
specific consumption of the grinding circuit decreases.
Increasing tailings dam
life
When applied in the earlier stages of the process, a smaller volume of gangue is processed consequently,
the quantity of fine tailings generated that must be disposed of in a tailings dam is reduced.
Reusing wate /tailings As the tailings from pre-concentration is coarse and easily dewatered, it can be used, among others, for
paving roads, or filling galleries (backfill), and depending on its characteristics, it can be sold as a by-
product (e.g., gravel, sand, etc), thereby generating profit.
Reducing water
consumption
There is less mass to be slurried /treated resulting in less water consumption.
Increasing mine life By rejecting part of the gangue, the mine cut-off grade decreases, which allows the exploitation of
marginal ores and, consequently, there is an expansion of the reserves.
Positive impact on
flotation
Pre-concentration allows metal recovery improvements and eliminates fluctuations in the grade of the
flotation feed. In such a case, reagent consumption can be optimized, and the circuit can be simplified
through a possible reduction in the usage of cleaner and/or scavenger operations.
Positive impact on the
thickening
Reduction of the thickening unit capacity demand and flocculant consumption, particularly in the
tailings, which has been reduced.
Increasing the
production
When applied in the waste, the feed throughput of the plant is lower but offers a better grade. Thus, it is
possible to produce the same amount of metal at lower feed rates, obtaining a margin for an increase in
production without requiring expansion of the capacity of the grinding and concentration circuits.
Figure 1. Mont Reed location (ArcelorMittal assets in red -Ibrango, 2013)