1500 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
Current performance testing provides limited informa-
tion on ore characteristics and no details on the bypass fines
fraction. In addition, no information is gathered on ore-
body variability or test results on a large number of samples
from each domain or lithology. (Once again, standard prac-
tice for other forms of met testing.)
In addition, performance testing is largely indepen-
dent of the overall process development design, where an
iterative process is used to optimize the flowsheet. Typical
development testing considers results from many aspects
of testing to guide flowsheet selection. This is difficult to
achieve through performance testing, conducted by an
equipment manufacturer independently of other testwork.
Companies that cannot collect a large sample mass
or cannot afford to complete performance testing, do not
assess their material—and this is a lost opportunity. In
addition, when completing scoping and prefeasibility stud-
ies with associated technical reports, a single pilot plant test
is not sufficient for a Qualified Person to take professional
responsibility and sign off.
It is the authors’ opinion the mining industry would
benefit from a standard protocol for pre-concentration
assessment, performed by independent personnel/laborato-
ries. This will allow test results to be shared and compared
and development of the test to be an industry initiative
rather than considered competitive advantage and some-
thing to be worked on in isolation. With this aim, the
authors are openly presenting a newly-developed testing
protocol with the objective of it being the basis of an indus-
try standard.
SRK TESTING PROTOCOL
The proposed test protocol currently being done by SRK
at Base Metallurgical Labs (BML) in Kamloops BC was
developed over a number of years. Initially, it focussed on
estimating differential breakage and metal upgrading from
crushing and screening alone. This was expanded to include
sensor sorting and in late 2023, included the adoption of a
dual-energy XRT sensor unit. This unit is jointly owned by
SRK and BML and operated independently of any sorter
manufacturer.
It is important to note this protocol provides insight
into the amenability of test samples to pre-concentration.
It does not mimic or replace performance testing currently
being done by manufacturers. The authors believe tremen-
dous value can be provided to projects by completing per-
formance tests at the right time and on the right test samples.
In addition, manufacturers and other specialized engineer-
ing companies have extensive knowledge and experience
in this field. However, as with other types of pilot testing,
performance tests should only be done once preliminary
testing has been done and confidence gained that a large
composite sample will provide meaningful results.
The SRK test protocol focusses on extracting as much
information as possible from a limited sample mass, gen-
erally sourced from half core intervals. This is all that is
available for early-stage studies, and test protocols for com-
minution, flotation, hydrometallurgy and dewatering have
all been developed for such samples. (As mentioned, sam-
ples sourced after primary crushing from existing opera-
tions can be tested).
Because of the close relationship between particle
breakage and coarse pre-concentration, the test protocol
was an extension to the well-established SMC test (SMC
Testing, 2024). A flowsheet outlining the test procedure is
shown in Figure 4 and all elements can be completed by
accredited commercial met labs with appropriate test appa-
ratuses. At this time, the dual-energy XRT sensor scanning
work is done by BML and to continue with the standard
testing approach, particles can be sent to BML for XRT
scanning. Over time, other labs can adopt the same scan-
ning unit and develop the testing expertise.
Sample mass requirements are dictated largely by the
SMC test, which is ideally conducted on 100 particles of
31×26 mm (or smaller fractions) at five energy levels. For
the XRT scanning work, 40 to 120 particles of 22×19 mm
are tested, or other size fraction are suitable for scanning.
For competent material, much less sample mass is required
to generate the combined 160 to 220 particles while softer
material requires a greater mass to generate sufficient par-
ticle numbers in these size fractions.
After crushing to generate the size fractions for test-
ing, the as-received fractions are assayed for baseline metal
deportment. The SMC test is completed on the 31×26 mm
fraction and results sent to JKTech Australia for certifica-
tion and reporting of standard parameters (DWi, Mi values,
A*b, and SCSE). The five specific comminution energy(Ecs)
levels (0.25kWh/t to 3.5kWh/t) generate broken particles
for sizing (and t10 determination) and are also assayed. The
change in grade deportment with Ecs compared with base-
line grade-by-size is used to estimate upgrading from crush-
ing and screening.
For the 22×19 mm fraction, trays of particles are
scanned using the dual-energy XRT unit. To keep test costs
to a minimum (an objective for the protocol), particles are
grouped into four categories based on particle ranking from
XRT response, typically done in duplicate for each sample.
Testing then demonstrates if assays follow the XRT group-
ings, then metals of interest are associated with atomic
density at this particle size. If requested, a larger number
Current performance testing provides limited informa-
tion on ore characteristics and no details on the bypass fines
fraction. In addition, no information is gathered on ore-
body variability or test results on a large number of samples
from each domain or lithology. (Once again, standard prac-
tice for other forms of met testing.)
In addition, performance testing is largely indepen-
dent of the overall process development design, where an
iterative process is used to optimize the flowsheet. Typical
development testing considers results from many aspects
of testing to guide flowsheet selection. This is difficult to
achieve through performance testing, conducted by an
equipment manufacturer independently of other testwork.
Companies that cannot collect a large sample mass
or cannot afford to complete performance testing, do not
assess their material—and this is a lost opportunity. In
addition, when completing scoping and prefeasibility stud-
ies with associated technical reports, a single pilot plant test
is not sufficient for a Qualified Person to take professional
responsibility and sign off.
It is the authors’ opinion the mining industry would
benefit from a standard protocol for pre-concentration
assessment, performed by independent personnel/laborato-
ries. This will allow test results to be shared and compared
and development of the test to be an industry initiative
rather than considered competitive advantage and some-
thing to be worked on in isolation. With this aim, the
authors are openly presenting a newly-developed testing
protocol with the objective of it being the basis of an indus-
try standard.
SRK TESTING PROTOCOL
The proposed test protocol currently being done by SRK
at Base Metallurgical Labs (BML) in Kamloops BC was
developed over a number of years. Initially, it focussed on
estimating differential breakage and metal upgrading from
crushing and screening alone. This was expanded to include
sensor sorting and in late 2023, included the adoption of a
dual-energy XRT sensor unit. This unit is jointly owned by
SRK and BML and operated independently of any sorter
manufacturer.
It is important to note this protocol provides insight
into the amenability of test samples to pre-concentration.
It does not mimic or replace performance testing currently
being done by manufacturers. The authors believe tremen-
dous value can be provided to projects by completing per-
formance tests at the right time and on the right test samples.
In addition, manufacturers and other specialized engineer-
ing companies have extensive knowledge and experience
in this field. However, as with other types of pilot testing,
performance tests should only be done once preliminary
testing has been done and confidence gained that a large
composite sample will provide meaningful results.
The SRK test protocol focusses on extracting as much
information as possible from a limited sample mass, gen-
erally sourced from half core intervals. This is all that is
available for early-stage studies, and test protocols for com-
minution, flotation, hydrometallurgy and dewatering have
all been developed for such samples. (As mentioned, sam-
ples sourced after primary crushing from existing opera-
tions can be tested).
Because of the close relationship between particle
breakage and coarse pre-concentration, the test protocol
was an extension to the well-established SMC test (SMC
Testing, 2024). A flowsheet outlining the test procedure is
shown in Figure 4 and all elements can be completed by
accredited commercial met labs with appropriate test appa-
ratuses. At this time, the dual-energy XRT sensor scanning
work is done by BML and to continue with the standard
testing approach, particles can be sent to BML for XRT
scanning. Over time, other labs can adopt the same scan-
ning unit and develop the testing expertise.
Sample mass requirements are dictated largely by the
SMC test, which is ideally conducted on 100 particles of
31×26 mm (or smaller fractions) at five energy levels. For
the XRT scanning work, 40 to 120 particles of 22×19 mm
are tested, or other size fraction are suitable for scanning.
For competent material, much less sample mass is required
to generate the combined 160 to 220 particles while softer
material requires a greater mass to generate sufficient par-
ticle numbers in these size fractions.
After crushing to generate the size fractions for test-
ing, the as-received fractions are assayed for baseline metal
deportment. The SMC test is completed on the 31×26 mm
fraction and results sent to JKTech Australia for certifica-
tion and reporting of standard parameters (DWi, Mi values,
A*b, and SCSE). The five specific comminution energy(Ecs)
levels (0.25kWh/t to 3.5kWh/t) generate broken particles
for sizing (and t10 determination) and are also assayed. The
change in grade deportment with Ecs compared with base-
line grade-by-size is used to estimate upgrading from crush-
ing and screening.
For the 22×19 mm fraction, trays of particles are
scanned using the dual-energy XRT unit. To keep test costs
to a minimum (an objective for the protocol), particles are
grouped into four categories based on particle ranking from
XRT response, typically done in duplicate for each sample.
Testing then demonstrates if assays follow the XRT group-
ings, then metals of interest are associated with atomic
density at this particle size. If requested, a larger number