XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2937
rougher flotation includes the concentrate of the scavenger
and the new feed of cyclone II overflow (Figure 1). The low
Au concentrate grade for fine particles in both scavenger
and rougher flotation demonstrates the limits of fine flota-
tion based on mechanical cells. As shown, a low Au grade
of 4.28 g/t in the fine particle size below 20 µm highlights
the limitation of the recovery of fine particles using existing
mechanical cells (Table 1), especially since this size fraction
contains the highest gold content in the feed.
The size-by-size analysis showed that the existing con-
ventional cells pulled out quite a lot of very fine gangues
into the scavenger concentrate negatively affecting the over-
all Au grade. The scavenger concentrate (feed to the pilot
Imhoflot) contains 78 wt. %of 20 µm with only 4.28 g/t
gold, about 51.8% gold distributes in this fine fraction.
Plant Final Tailings
The average gold content at the time (April 2023) of pilot
testing was about 0.46 g/t Au which discharges to the tail-
ings pond (sampling point 2—Figure 1). Table 2 shows
the gold grade and gold distribution of the scavenger tails
obtained from sieving and chemical analysis. The finest size
fraction 38 µm contains about 65.6% of the gold at a con-
centration of 0.54 g/t.
RESULTS AND DISCUSSIONS
Scavenger Concentrate Streamline
The particle size distribution of existing scavenger concen-
trate (feed to pilot plant), combined concentrate (cell 1 and
cell 2), concentrate cell 1, concentrate cell 2 and tailings
(tails cell 1 and tails cell 2) shows in Figure 3. d80 of the
Figure 1. Simplified process flowsheet of the gold processing plant highlighting the points of modification evaluated in this study
rougher flotation includes the concentrate of the scavenger
and the new feed of cyclone II overflow (Figure 1). The low
Au concentrate grade for fine particles in both scavenger
and rougher flotation demonstrates the limits of fine flota-
tion based on mechanical cells. As shown, a low Au grade
of 4.28 g/t in the fine particle size below 20 µm highlights
the limitation of the recovery of fine particles using existing
mechanical cells (Table 1), especially since this size fraction
contains the highest gold content in the feed.
The size-by-size analysis showed that the existing con-
ventional cells pulled out quite a lot of very fine gangues
into the scavenger concentrate negatively affecting the over-
all Au grade. The scavenger concentrate (feed to the pilot
Imhoflot) contains 78 wt. %of 20 µm with only 4.28 g/t
gold, about 51.8% gold distributes in this fine fraction.
Plant Final Tailings
The average gold content at the time (April 2023) of pilot
testing was about 0.46 g/t Au which discharges to the tail-
ings pond (sampling point 2—Figure 1). Table 2 shows
the gold grade and gold distribution of the scavenger tails
obtained from sieving and chemical analysis. The finest size
fraction 38 µm contains about 65.6% of the gold at a con-
centration of 0.54 g/t.
RESULTS AND DISCUSSIONS
Scavenger Concentrate Streamline
The particle size distribution of existing scavenger concen-
trate (feed to pilot plant), combined concentrate (cell 1 and
cell 2), concentrate cell 1, concentrate cell 2 and tailings
(tails cell 1 and tails cell 2) shows in Figure 3. d80 of the
Figure 1. Simplified process flowsheet of the gold processing plant highlighting the points of modification evaluated in this study