XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 1505
CASE STUDIES
As illustrations of SRK test outcomes, case studies are
briefly summarised for a high-grade gold project and man-
ganese oxide project, both at scoping level stages of study.
All results were generated from half core samples of less
than 30kg and consistent (unoptimized) pre-concentration
flowsheets were simulated: primary crushing followed by
screening at 25 mm with the coarse fraction XRT sensor
tested to achieve high metal recoveries to accepted product.
Gold Project
Figure 10 summarises the lab test results in flowsheet form.
For this very hard material, only 26% of the crusher prod-
uct would bypass the sorter but showed considerable gold
upgrade from 9.5g/t to 19.0g/t Au. The screen oversize
fraction was lower in grade at 5.6g/t, but the XRT sensor
response indicated 20% of the material was very low-grade
at 0.7g/t Au. The final accepted product was 10.5g/t Au at
85% of the circuit feed.
Clearly, alternate circuit conditions and XRT sensor
mass pull options could be simulated and these scenarios
are all considered as part of SRK’s economic evaluations.
Another possible outcome is pre-concentration using varia-
tions of this circuit flowsheet may not be viable for this grade
material instead, lower-grade samples should be tested.
These samples showed limited bypass but there is poten-
tial for high upgrading to the finer fractions. Testwork is
ongoing with additional samples to support this simulation.
Manganese Project
The results in Figure 11 provide a significant contrast to the
hard, gold project discussed above. The manganese oxide
ore and waste were varying in hardness, and for this sample,
50% of the material reported to the bypass fraction with
limited/no metal upgrading. The XRT response indicated
40% of the coarse fraction could be rejected at a low grade
(3.3% Mn). The final accepted product was 80% of the
original sample at 21.8% Mn. A side benefit of the pre-
concentration flowsheet was rejection of calcium minerals
which are costly to process in the downstream plant.
These samples indicated the potential for pre-concen-
tration may be limited more by the degree of crushing/ size
reduction as the bypass material reported limited upgrad-
ing of metal. Alternate crushing strategies (pre-screening
for an example) should be applied to maximize screen over-
size reporting to the XRT sensor. A range of options can be
considered and simulated using the SRK lab test protocol.
In addition, geometallurgical modelling of the pre-concen-
tration results will likely be the next phase due to the wide
range of mineral composition/lithology of the ore samples.
CONCLUDING REMARKS
As part of SRK’s involvement in investigating pre-concen-
tration opportunities for both early-stage studies and exist-
ing operations, a lab test protocol has been developed. This
protocol can be performed on small mass samples of half
core or primary crushed material from existing operations.
Source: SRK 2024
Figure 10. Simulated pre-concentration flowsheet from SRK protocol (gold sample)
CASE STUDIES
As illustrations of SRK test outcomes, case studies are
briefly summarised for a high-grade gold project and man-
ganese oxide project, both at scoping level stages of study.
All results were generated from half core samples of less
than 30kg and consistent (unoptimized) pre-concentration
flowsheets were simulated: primary crushing followed by
screening at 25 mm with the coarse fraction XRT sensor
tested to achieve high metal recoveries to accepted product.
Gold Project
Figure 10 summarises the lab test results in flowsheet form.
For this very hard material, only 26% of the crusher prod-
uct would bypass the sorter but showed considerable gold
upgrade from 9.5g/t to 19.0g/t Au. The screen oversize
fraction was lower in grade at 5.6g/t, but the XRT sensor
response indicated 20% of the material was very low-grade
at 0.7g/t Au. The final accepted product was 10.5g/t Au at
85% of the circuit feed.
Clearly, alternate circuit conditions and XRT sensor
mass pull options could be simulated and these scenarios
are all considered as part of SRK’s economic evaluations.
Another possible outcome is pre-concentration using varia-
tions of this circuit flowsheet may not be viable for this grade
material instead, lower-grade samples should be tested.
These samples showed limited bypass but there is poten-
tial for high upgrading to the finer fractions. Testwork is
ongoing with additional samples to support this simulation.
Manganese Project
The results in Figure 11 provide a significant contrast to the
hard, gold project discussed above. The manganese oxide
ore and waste were varying in hardness, and for this sample,
50% of the material reported to the bypass fraction with
limited/no metal upgrading. The XRT response indicated
40% of the coarse fraction could be rejected at a low grade
(3.3% Mn). The final accepted product was 80% of the
original sample at 21.8% Mn. A side benefit of the pre-
concentration flowsheet was rejection of calcium minerals
which are costly to process in the downstream plant.
These samples indicated the potential for pre-concen-
tration may be limited more by the degree of crushing/ size
reduction as the bypass material reported limited upgrad-
ing of metal. Alternate crushing strategies (pre-screening
for an example) should be applied to maximize screen over-
size reporting to the XRT sensor. A range of options can be
considered and simulated using the SRK lab test protocol.
In addition, geometallurgical modelling of the pre-concen-
tration results will likely be the next phase due to the wide
range of mineral composition/lithology of the ore samples.
CONCLUDING REMARKS
As part of SRK’s involvement in investigating pre-concen-
tration opportunities for both early-stage studies and exist-
ing operations, a lab test protocol has been developed. This
protocol can be performed on small mass samples of half
core or primary crushed material from existing operations.
Source: SRK 2024
Figure 10. Simulated pre-concentration flowsheet from SRK protocol (gold sample)