1400 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
CONCLUSIONS
The small fragment HIT test trial results are very encourag-
ing, over a good range of rock impact hardness, as defined
by the JKDWT Axb index. The trial results indicate that
10g of 1.7×1.4 mm material yields the most significant cor-
relation with the HIT Axb index.
Of the two PSD metrics used in the analysis, the
%Unbroken was less reliable, especially using the smaller
fractions. The best option appears to be a normalized %
passing metric, for example, the %passing 1/2 relative size.
More work is required to determine whether there is a bet-
ter metric for the SFH data analysis and subsequent model-
ling against standard ore hardness parameters.
The correlation for Axb with the %passing 1/2 relative
size is very strong across the 7 samples, similar to initial 3
samples which bodes well for the robustness of the rela-
tionship. It is not clear whether the 2.0×1.7 mm fraction
would be just as reliable or better. Further work is required
to confirm.
The trial has yet to consider correlations with other
hardness indices such as the Bond Work Index (BWi), but
this will be part of validation analysis to see if the SFH test
can also be used to reliably estimate the BWi.
The SFH test is much simpler and faster than single par-
ticle tests like JKDWT, SMC and standard HIT, and grind-
ing tests such as the Bond Ball Mill Work Index test, and is
considered an opportunity for early exploration programs to
understand the deposit and target further drilling programs
and areas for advanced metallurgical testing. The SFH test
using 10g of 1.7×1.4 mm fragments quantifies the break-
age response of approximately 1400 fragments, compared to
only 100 fragments in the SMC test. Hence the SFH test is
considerably more representative of the whole sample.
The SFH test requires only 10g, which is easily pre-
pared without the problems of selecting typical coarse par-
ticles, particularly if they are not available as in exploration
programs. The benefit is that the HIT can be deployed on
samples finer than 2 mm generated from exploration drill-
ing, offering the potential for targeted exploration drilling
and focussed geometallurgy sampling, affording potential
costs savings at the front end of a project/resource defini-
tion. The SFH test is a single impact on 10g of narrowly
sized fragments, followed by screening of the product using
5 sieves starting with the top size of the fragments. The total
SFH test time would be less than 10 minutes per sample.
ACKNOWLEDGMENTS
authors would like to acknowledge Debora Araujo from
Rio Tinto Exploration (Exploration Technical Knowledge
Team, Bundoora, Australia) for initiating the work and
contributions to this project. The authors would like to
acknowledge Steve Bradford, for his mentoring in planning
the trial at BML. The SFH test protocol was developed
with the support from Rio Tinto Exploration. However,
any opinions, findings, conclusions, or recommendations
expressed herein are those of the authors and do not neces-
sarily reflect the views of Rio Tinto.
REFERENCES
Bergeron, Y., Kojovic, T., Gagnon, M-d-N., &Okono,
P., 2017. Applicability of the HIT for Evaluating
Comminution and Geomechanical Parameters from
Drill Core Samples—The Odyssey Project Case Study,
Proceedings from COM2017, Vancouver, August.
Bond, F C, 1961. Crushing and grinding calcula-
tions, Brit Chem Eng, part I: 6(6):378–385, part II:
6(8):543–548.
Davaanyam, Z., 2015. Piston Press Test Procedures for
Predicting Energy–Size Reduction of High Pressure
Grinding Rolls, UBC PhD Thesis, July.
Kojovic, T., 2016. HIT -A Portable Field Device for Rapid
Hardness Index Testing at Site. Proceedings AusIMM
Mill Operators’ Conference 2016, October, Perth WA,
pp9–16.
Leetmaa, K., Bergeron, Y. and Kojovic, T., 2019. The value
of Daily HIT Ore Hardness Testing of SAG Feed at the
Meadowbank Gold Mine, Proceedings from SAG2019,
Vancouver, September.
Morrell, S, 2004. Predicting the specific energy of
autogenous and semi-autogenous mills from small
diameter drill core samples, Minerals Engineering,
17(3):447–451.
Napier-Munn, T J, Morrell, S, Morrison, R D and Kojovic,
T, 1996. Mineral Comminution Circuits: Their
Operation and Optimization, (Julius Kruttschnitt
Mineral Research Centre: Brisbane.
Varianemil, D., Kojovic, T., Hakim, D., Dilaga, R. and
Condori, P., 2023. Ore Hardness Mapping of Batu
Hijau Ore Deposit Using the Hardness Index Tester,
Proceedings from SAG2023, Vancouver, September.
Schönert, K. (1988). A first survey of grinding with high-
compression roller mills. International Journal of
Mineral Processing, 22(1‑4):401–412.
Schönert, K. (1996). The influence of particle bed con-
figurations and confinements on particle break-
age. International Journal of Mineral Processing,
44‑45:1–16.
Whiten, W.J., (2020). A simple method for determining
the breakage properties of fine particles. Research Gate
article, doi: 10.13140/RG.2.2.13567.64167, June.
CONCLUSIONS
The small fragment HIT test trial results are very encourag-
ing, over a good range of rock impact hardness, as defined
by the JKDWT Axb index. The trial results indicate that
10g of 1.7×1.4 mm material yields the most significant cor-
relation with the HIT Axb index.
Of the two PSD metrics used in the analysis, the
%Unbroken was less reliable, especially using the smaller
fractions. The best option appears to be a normalized %
passing metric, for example, the %passing 1/2 relative size.
More work is required to determine whether there is a bet-
ter metric for the SFH data analysis and subsequent model-
ling against standard ore hardness parameters.
The correlation for Axb with the %passing 1/2 relative
size is very strong across the 7 samples, similar to initial 3
samples which bodes well for the robustness of the rela-
tionship. It is not clear whether the 2.0×1.7 mm fraction
would be just as reliable or better. Further work is required
to confirm.
The trial has yet to consider correlations with other
hardness indices such as the Bond Work Index (BWi), but
this will be part of validation analysis to see if the SFH test
can also be used to reliably estimate the BWi.
The SFH test is much simpler and faster than single par-
ticle tests like JKDWT, SMC and standard HIT, and grind-
ing tests such as the Bond Ball Mill Work Index test, and is
considered an opportunity for early exploration programs to
understand the deposit and target further drilling programs
and areas for advanced metallurgical testing. The SFH test
using 10g of 1.7×1.4 mm fragments quantifies the break-
age response of approximately 1400 fragments, compared to
only 100 fragments in the SMC test. Hence the SFH test is
considerably more representative of the whole sample.
The SFH test requires only 10g, which is easily pre-
pared without the problems of selecting typical coarse par-
ticles, particularly if they are not available as in exploration
programs. The benefit is that the HIT can be deployed on
samples finer than 2 mm generated from exploration drill-
ing, offering the potential for targeted exploration drilling
and focussed geometallurgy sampling, affording potential
costs savings at the front end of a project/resource defini-
tion. The SFH test is a single impact on 10g of narrowly
sized fragments, followed by screening of the product using
5 sieves starting with the top size of the fragments. The total
SFH test time would be less than 10 minutes per sample.
ACKNOWLEDGMENTS
authors would like to acknowledge Debora Araujo from
Rio Tinto Exploration (Exploration Technical Knowledge
Team, Bundoora, Australia) for initiating the work and
contributions to this project. The authors would like to
acknowledge Steve Bradford, for his mentoring in planning
the trial at BML. The SFH test protocol was developed
with the support from Rio Tinto Exploration. However,
any opinions, findings, conclusions, or recommendations
expressed herein are those of the authors and do not neces-
sarily reflect the views of Rio Tinto.
REFERENCES
Bergeron, Y., Kojovic, T., Gagnon, M-d-N., &Okono,
P., 2017. Applicability of the HIT for Evaluating
Comminution and Geomechanical Parameters from
Drill Core Samples—The Odyssey Project Case Study,
Proceedings from COM2017, Vancouver, August.
Bond, F C, 1961. Crushing and grinding calcula-
tions, Brit Chem Eng, part I: 6(6):378–385, part II:
6(8):543–548.
Davaanyam, Z., 2015. Piston Press Test Procedures for
Predicting Energy–Size Reduction of High Pressure
Grinding Rolls, UBC PhD Thesis, July.
Kojovic, T., 2016. HIT -A Portable Field Device for Rapid
Hardness Index Testing at Site. Proceedings AusIMM
Mill Operators’ Conference 2016, October, Perth WA,
pp9–16.
Leetmaa, K., Bergeron, Y. and Kojovic, T., 2019. The value
of Daily HIT Ore Hardness Testing of SAG Feed at the
Meadowbank Gold Mine, Proceedings from SAG2019,
Vancouver, September.
Morrell, S, 2004. Predicting the specific energy of
autogenous and semi-autogenous mills from small
diameter drill core samples, Minerals Engineering,
17(3):447–451.
Napier-Munn, T J, Morrell, S, Morrison, R D and Kojovic,
T, 1996. Mineral Comminution Circuits: Their
Operation and Optimization, (Julius Kruttschnitt
Mineral Research Centre: Brisbane.
Varianemil, D., Kojovic, T., Hakim, D., Dilaga, R. and
Condori, P., 2023. Ore Hardness Mapping of Batu
Hijau Ore Deposit Using the Hardness Index Tester,
Proceedings from SAG2023, Vancouver, September.
Schönert, K. (1988). A first survey of grinding with high-
compression roller mills. International Journal of
Mineral Processing, 22(1‑4):401–412.
Schönert, K. (1996). The influence of particle bed con-
figurations and confinements on particle break-
age. International Journal of Mineral Processing,
44‑45:1–16.
Whiten, W.J., (2020). A simple method for determining
the breakage properties of fine particles. Research Gate
article, doi: 10.13140/RG.2.2.13567.64167, June.