626 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
filtration), and the efficiency of the filtration equipment. In
this study, a conservative assumption of 2.0 kWh/t specific
energy consumption was made for the filter press opera-
tion to achieve a final dry stack tailing moisture content of
~15% by weight.
COMPARISON OF COPPER
PRODUCTION AND WATER AND
ENERGY CONSUMPTION
To compare the conventional base case flowsheet and future
flowsheet, the simplified process design criteria are shown
in Table 4, including solid, metal and water inputs as well
as energy usage. The mine excavates 150,000 tpd of com-
bined ore and waste. For the base case, 50,000 tpd with
a grade of 0.3% Cu is fed to the conventional SABC and
flotation process as presented in Figure 1. As per Figure 2,
for the future flowsheet case, waste is rejected from BOS
and particle sorting. Fines from the particle sorting circuit
are added to the HPGR circuit feed with the assumption
that this stream contains significant copper. The net flow to
HPGR comminution is 47,435 tpd with a grade of 0.40%
Cu. Plant availability was assumed to be the same for both
flowsheets.
For the base case, ball mill grinding reduces particle
size to P80 of 150 microns ahead of rougher flotation,
which produces a mass yield of 15%. The rougher product
is reground in a conventional tumbling ball mill to a P80
of 30 microns ahead of cleaning flotation. For the future
flowsheet, the HPGR product is ground in a coarse stirred
mill to a P80 of 250 microns for coarse particle rougher
flotation with a mass yield of 25% (relative to the coarse
particle flotation feed stream). The coarse particle flotation
concentrate is reground in a stirred mill to the same target
size as the base case of 30 microns. Rougher and cleaner
flotation recoveries are assumed to be the same for both
circuits.
The base case rougher flotation and cleaner scavenger
tailings are pumped to the tailings storage facility. For the
future flowsheet, coarse particle flotation tailings are dewa-
tered using a screw classifier and are either combined with
cleaner scavenger tailings ahead of thickening and filtration
for water recycling and dry stacked.
The main impacts of the future flowsheet in compari-
son to the base case are presented in Table 5. The details
showing the solids, metal, and water balances as well as
energy usage are appended in Table 6 and 7. All results are
based on the data obtained from UBC research programs
and the assumptions made for selected parameters are based
on published information. For water consumption and
energy consumption, results are presented both on a per
tonne of wet ore processed basis as well as on a per tonne of
copper produced basis. The per tonne of wet ore processed
relates to SAG circuit feed and HPGR circuit feed for the
base case and future flowsheet scenarios. The consumptions
represent direct usage and do not consider embodied water
and energy.
As summarized in Table 5, water consumption is sig-
nificantly reduced with the future process. On a per tonne
of wet ore processed basis, the consumption decreased from
0.68 m3/t to 0.20 m3/t which is a 70% reduction in water
Table 4. High level process design criteria for base case and future flowsheet
Capacity Unit Base Flowsheet Future Flowsheet
Mine Throughput tpd 150,000 150,000
Strip Ratio -2 2
Mine Grade, Cu %0.3 0.3
Plant Throughput tpd 50,000 47,435
Plant Feed Grade, Cu %0.30 0.40
Plant Feed Moisture Content %3 3
Crushing Plant Availability %75 75
Crushing Plant Throughput tph 2,778 2,635
Overall Plant Availability %92 92
Overall Plant Throughput tph 2,264 2,148
Primary Grind Size microns 150 250
Regrind Size microns 30 30
Rougher Flotation Mass Pull %15 25
Rougher Flotation Recovery %90 90
Cleaner Flotation Mass Pull %7 4
Cleaner Flotation Recovery %95 95
Recovered Water from Tailings %70 85
filtration), and the efficiency of the filtration equipment. In
this study, a conservative assumption of 2.0 kWh/t specific
energy consumption was made for the filter press opera-
tion to achieve a final dry stack tailing moisture content of
~15% by weight.
COMPARISON OF COPPER
PRODUCTION AND WATER AND
ENERGY CONSUMPTION
To compare the conventional base case flowsheet and future
flowsheet, the simplified process design criteria are shown
in Table 4, including solid, metal and water inputs as well
as energy usage. The mine excavates 150,000 tpd of com-
bined ore and waste. For the base case, 50,000 tpd with
a grade of 0.3% Cu is fed to the conventional SABC and
flotation process as presented in Figure 1. As per Figure 2,
for the future flowsheet case, waste is rejected from BOS
and particle sorting. Fines from the particle sorting circuit
are added to the HPGR circuit feed with the assumption
that this stream contains significant copper. The net flow to
HPGR comminution is 47,435 tpd with a grade of 0.40%
Cu. Plant availability was assumed to be the same for both
flowsheets.
For the base case, ball mill grinding reduces particle
size to P80 of 150 microns ahead of rougher flotation,
which produces a mass yield of 15%. The rougher product
is reground in a conventional tumbling ball mill to a P80
of 30 microns ahead of cleaning flotation. For the future
flowsheet, the HPGR product is ground in a coarse stirred
mill to a P80 of 250 microns for coarse particle rougher
flotation with a mass yield of 25% (relative to the coarse
particle flotation feed stream). The coarse particle flotation
concentrate is reground in a stirred mill to the same target
size as the base case of 30 microns. Rougher and cleaner
flotation recoveries are assumed to be the same for both
circuits.
The base case rougher flotation and cleaner scavenger
tailings are pumped to the tailings storage facility. For the
future flowsheet, coarse particle flotation tailings are dewa-
tered using a screw classifier and are either combined with
cleaner scavenger tailings ahead of thickening and filtration
for water recycling and dry stacked.
The main impacts of the future flowsheet in compari-
son to the base case are presented in Table 5. The details
showing the solids, metal, and water balances as well as
energy usage are appended in Table 6 and 7. All results are
based on the data obtained from UBC research programs
and the assumptions made for selected parameters are based
on published information. For water consumption and
energy consumption, results are presented both on a per
tonne of wet ore processed basis as well as on a per tonne of
copper produced basis. The per tonne of wet ore processed
relates to SAG circuit feed and HPGR circuit feed for the
base case and future flowsheet scenarios. The consumptions
represent direct usage and do not consider embodied water
and energy.
As summarized in Table 5, water consumption is sig-
nificantly reduced with the future process. On a per tonne
of wet ore processed basis, the consumption decreased from
0.68 m3/t to 0.20 m3/t which is a 70% reduction in water
Table 4. High level process design criteria for base case and future flowsheet
Capacity Unit Base Flowsheet Future Flowsheet
Mine Throughput tpd 150,000 150,000
Strip Ratio -2 2
Mine Grade, Cu %0.3 0.3
Plant Throughput tpd 50,000 47,435
Plant Feed Grade, Cu %0.30 0.40
Plant Feed Moisture Content %3 3
Crushing Plant Availability %75 75
Crushing Plant Throughput tph 2,778 2,635
Overall Plant Availability %92 92
Overall Plant Throughput tph 2,264 2,148
Primary Grind Size microns 150 250
Regrind Size microns 30 30
Rougher Flotation Mass Pull %15 25
Rougher Flotation Recovery %90 90
Cleaner Flotation Mass Pull %7 4
Cleaner Flotation Recovery %95 95
Recovered Water from Tailings %70 85