XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 1501
of groups can be assayed (or even particle-by-particle) to
improve test resolution, but at an added cost.
Before each XRT group is assayed, the breakage prop-
erties are measured using the Hardness Index Test (HIT)
(SimSAGe, 2024) which is done at one Ecs level on the
22×19 mm fraction. This provides information on the
change in hardness (A*b values) resulting from pre-concen-
tration, another possible added benefit to the downstream
process.
One of the most interesting outcomes of this type of
testing is observing the presence of barren (or low-grade)
particles present in the mixture of ore samples and, in con-
trast, the presence of high-grade particles in a mixture of
waste samples. This is something not typically observed,
as “internal dilution” due to ore and waste contacts is not
considered something that can be improved upon and is
only dictated by the smallest minable block, although the
industry is applying more focus and effort at evaluating this
particular aspect of mining.
Another benefit of this protocol is the XRT lab unit can
be used to generate representative samples of concentrated
material for downstream testing (e.g., flotation, leaching,
etc.). This will provide a more integrated assessment, with
design considerations evaluated using downstream testing
results.
Differential Breakage
To estimate differential breakage of metallic minerals (e.g.,
softer sulphides), the change in metal deportment for the
varying Ecs levels is compared with baseline size-by-assay
results. Figure 5 shows normalized SMC test broken prod-
uct size distributions compared to a full-scale primary
crusher product. It is this self-similarity (used to define a
fractal dimension) that suggests grade deportment at the
test scale can be used to estimate deportment for a primary
crusher product distribution.
Figure 6 shows the results of cumulative metal recovery
versus mass results for a test sample broken at 0.1kWh/t
to 0.4kWh/t Ecs levels. Even this copper porphyry sample
measured 80% of the contained copper could be recov-
ered in the finer size fractions that represented 62% of the
material.
The results of this breakage testing are used to esti-
mate the size distributions after crushing and screening and
metal upgrade to fine versus coarse particle size fractions.
Source: SRK 2024
Figure 4. SRK lab testing protocol to assess pre-concentration
of groups can be assayed (or even particle-by-particle) to
improve test resolution, but at an added cost.
Before each XRT group is assayed, the breakage prop-
erties are measured using the Hardness Index Test (HIT)
(SimSAGe, 2024) which is done at one Ecs level on the
22×19 mm fraction. This provides information on the
change in hardness (A*b values) resulting from pre-concen-
tration, another possible added benefit to the downstream
process.
One of the most interesting outcomes of this type of
testing is observing the presence of barren (or low-grade)
particles present in the mixture of ore samples and, in con-
trast, the presence of high-grade particles in a mixture of
waste samples. This is something not typically observed,
as “internal dilution” due to ore and waste contacts is not
considered something that can be improved upon and is
only dictated by the smallest minable block, although the
industry is applying more focus and effort at evaluating this
particular aspect of mining.
Another benefit of this protocol is the XRT lab unit can
be used to generate representative samples of concentrated
material for downstream testing (e.g., flotation, leaching,
etc.). This will provide a more integrated assessment, with
design considerations evaluated using downstream testing
results.
Differential Breakage
To estimate differential breakage of metallic minerals (e.g.,
softer sulphides), the change in metal deportment for the
varying Ecs levels is compared with baseline size-by-assay
results. Figure 5 shows normalized SMC test broken prod-
uct size distributions compared to a full-scale primary
crusher product. It is this self-similarity (used to define a
fractal dimension) that suggests grade deportment at the
test scale can be used to estimate deportment for a primary
crusher product distribution.
Figure 6 shows the results of cumulative metal recovery
versus mass results for a test sample broken at 0.1kWh/t
to 0.4kWh/t Ecs levels. Even this copper porphyry sample
measured 80% of the contained copper could be recov-
ered in the finer size fractions that represented 62% of the
material.
The results of this breakage testing are used to esti-
mate the size distributions after crushing and screening and
metal upgrade to fine versus coarse particle size fractions.
Source: SRK 2024
Figure 4. SRK lab testing protocol to assess pre-concentration