XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 653
during the feasibility study to validate the robustness of the
low-alkaline process. Details of the ore types are not dis-
cussed here mainly to limit content that are not relevant to
the main theme of this paper.
Both Tables 4 and 5 show that the low alkaline scheme
gave significantly better results than the conventional high
lime scheme for almost all ore types. On average, copper
recovery was about 6% higher with better copper concen-
trate grade for the low alkaline scheme based on the locked
cycle test program. These results were validated further
using pilot scale testing for different composites represent-
ing life-of-mine.
The low alkaline process improved project econom-
ics due to a significant increase in copper revenue as the
life-of-mine copper recovery was almost 6% higher for the
low alkaline scheme than for the conventional high lime
scheme.
Other applications of the low-alkaline process
The low alkaline process was further evaluated with vari-
ous non-conventional water sources due to the challenges
encountered in making fresh water available for these proj-
ects. Table 6 demonstrates the benefit of this process for a
major copper-gold deposit using seawater.
Table 6 shows that the low alkaline process improved
copper recovery by about 7% with a significantly better
concentrate grade. Importantly the flotation performance
of the high lime scheme with sea water was poor due to
buffering of slurry pH at around 9 resulting in its inability
to depress pyrite. The low alkaline scheme at natural pH,
however, did not show a significant detrimental effect on
flotation performance. This confirms the robustness of the
low alkaline scheme in depressing pyrite at natural pH even
for poor quality water as previously observed for other ore
bodies.
Table 3. Comparison of the locked cycle results for three ore types using cyanide and AMBS schemes
Samples Schemes
Head
Cu %
Concentrate
Mass pull %
Concentrate
Cu %
Recovery
Cu %
A Low alkaline 0.48 1.36 35.1 92.2
A High lime 0.48 1.31 33.0 86.7
B Low alkaline 0.53 1.62 35.6 91.1
B High lime 0.53 1.73 34.9 88.4
C Low alkaline 0.31 0.90 36.1 90.0
C High lime 0.31 0.84 37.0 84.4
Table 4. Locked cycle test results for the 16 variability samples using the conventional high lime scheme
Comp
No Ore Types
%of Ore
Deposit
Head
Cu %
Concentrate
Cu %
Mass Pull
%
Recovery
Cu %
1 PFB1 -POT 5.0 0.59 28.3 1.90 91.7
2 PFB1 -MIX 2.0 0.42 28.2 1.08 72.2
3 PFB2 -POT 5.0 0.61 32.9 1.51 80.9
4 PFB2 -MIX 3.0 0.51 31.3 1.41 86.1
5 VIN -POT 3.0 0.69 30.5 1.88 83.6
6 VIN -MIX 4.0 0.43 33.3 1.14 88.5
7 VIN -SCC 6.0 0.36 25.4 1.10 78.0
8 VFL -POT 5.0 0.67 29.8 2.01 89.5
9 VFL -MIX 7.0 0.60 34.0 1.59 89.9
10 VFL -SCC 9.0 0.61 32.2 1.70 90.1
11 PFB1 -SCC 4.0 0.56 29.8 1.66 87.5
12 PFB1 -SCC 11.0 0.51 32.9 1.37 88.8
13 PFB2 -SCC 5.0 0.56 26.7 1.64 81.0
14 VIN – MIX 2 1.0 0.64 31.0 1.73 84.5
15 VIN –SCC 2 8.0 0.52 28.7 1.42 78.5
16 VFL – MIX 2 4.0 0.53 30.7 1.49 87.1
Weighted average 100.0 0.55 30.6 1.53 85.7
during the feasibility study to validate the robustness of the
low-alkaline process. Details of the ore types are not dis-
cussed here mainly to limit content that are not relevant to
the main theme of this paper.
Both Tables 4 and 5 show that the low alkaline scheme
gave significantly better results than the conventional high
lime scheme for almost all ore types. On average, copper
recovery was about 6% higher with better copper concen-
trate grade for the low alkaline scheme based on the locked
cycle test program. These results were validated further
using pilot scale testing for different composites represent-
ing life-of-mine.
The low alkaline process improved project econom-
ics due to a significant increase in copper revenue as the
life-of-mine copper recovery was almost 6% higher for the
low alkaline scheme than for the conventional high lime
scheme.
Other applications of the low-alkaline process
The low alkaline process was further evaluated with vari-
ous non-conventional water sources due to the challenges
encountered in making fresh water available for these proj-
ects. Table 6 demonstrates the benefit of this process for a
major copper-gold deposit using seawater.
Table 6 shows that the low alkaline process improved
copper recovery by about 7% with a significantly better
concentrate grade. Importantly the flotation performance
of the high lime scheme with sea water was poor due to
buffering of slurry pH at around 9 resulting in its inability
to depress pyrite. The low alkaline scheme at natural pH,
however, did not show a significant detrimental effect on
flotation performance. This confirms the robustness of the
low alkaline scheme in depressing pyrite at natural pH even
for poor quality water as previously observed for other ore
bodies.
Table 3. Comparison of the locked cycle results for three ore types using cyanide and AMBS schemes
Samples Schemes
Head
Cu %
Concentrate
Mass pull %
Concentrate
Cu %
Recovery
Cu %
A Low alkaline 0.48 1.36 35.1 92.2
A High lime 0.48 1.31 33.0 86.7
B Low alkaline 0.53 1.62 35.6 91.1
B High lime 0.53 1.73 34.9 88.4
C Low alkaline 0.31 0.90 36.1 90.0
C High lime 0.31 0.84 37.0 84.4
Table 4. Locked cycle test results for the 16 variability samples using the conventional high lime scheme
Comp
No Ore Types
%of Ore
Deposit
Head
Cu %
Concentrate
Cu %
Mass Pull
%
Recovery
Cu %
1 PFB1 -POT 5.0 0.59 28.3 1.90 91.7
2 PFB1 -MIX 2.0 0.42 28.2 1.08 72.2
3 PFB2 -POT 5.0 0.61 32.9 1.51 80.9
4 PFB2 -MIX 3.0 0.51 31.3 1.41 86.1
5 VIN -POT 3.0 0.69 30.5 1.88 83.6
6 VIN -MIX 4.0 0.43 33.3 1.14 88.5
7 VIN -SCC 6.0 0.36 25.4 1.10 78.0
8 VFL -POT 5.0 0.67 29.8 2.01 89.5
9 VFL -MIX 7.0 0.60 34.0 1.59 89.9
10 VFL -SCC 9.0 0.61 32.2 1.70 90.1
11 PFB1 -SCC 4.0 0.56 29.8 1.66 87.5
12 PFB1 -SCC 11.0 0.51 32.9 1.37 88.8
13 PFB2 -SCC 5.0 0.56 26.7 1.64 81.0
14 VIN – MIX 2 1.0 0.64 31.0 1.73 84.5
15 VIN –SCC 2 8.0 0.52 28.7 1.42 78.5
16 VFL – MIX 2 4.0 0.53 30.7 1.49 87.1
Weighted average 100.0 0.55 30.6 1.53 85.7