1390
Application of HIT in Orebody Hardness Domaining Using
Exploration Samples
T Kojovic
SimSAGe Pty Ltd, Australia
C Bucknell, A Lam,
Brisbane Met Lab, Australia
ABSTRACT: One of the challenges in orebody domaining in early exploration stage characterization programs,
is availability of meaningful metallurgical data to target exploration drilling on prospects with a higher confidence
of return. The HIT device has been successfully deployed in early metallurgical testing programs globally to
help focus early resource definition and progress project development. During drilling programs however, access
to larger sample fragments for ore hardness testing, especially related to parameters relevant to crushing and
SAG/AG mill grinding, is generally not possible. To this end, an experimental study has been initiated at
the Brisbane Metallurgical Laboratory in Australia to understand if HIT testing on –2 mm fragments could
provide a solution. The proof-of-concept trial focused on 7 distinct rock samples selected to have a wide range
of hardness ranging from 30 to 330, as defined by the well-known JKDWT Axb index. The standard HIT test
protocol was modified to suit the small fragment constraint, and a wide range of test parameters was investigated
aiming to find the most viable option to estimate the Axb index from tests on an unconfined bed of narrowly
sized fragments below 2 mm. The preliminary results indicate that it is possible to reliably estimate the Axb
index from testing less than 15g of the same material below 2 mm using the modified HIT test. This paper
describes the initial trial and the results obtained for standard and small fragment HIT tests.
INTRODUCTION
The mining industry has for the longest time been testing
ore hardness requiring significant investment in cost and
time, typically Bond ball mill Work Index and SMC test ® /
JKDWT Axb (Bond, 1961 Morrell, 2004). The Axb index
has become well known in the mining industry as a reli-
able measure of ore hardness in impact or crushing, evident
in the numerous case studies reported at mining confer-
ences since the late 1980s. Experimental determination of
Axb using the above devices/tests requires samples, with
sufficient mass, to be sent to designated laboratories, reg-
istered to conduct such tests. This protocol is accepted for
bankable and commercial testing, where material charac-
terisation data is used in conjunction with machine specific
data in modelling and simulation, and power-based calcu-
lations. However, for geometallurgical or orebody domain-
ing in early exploration stage characterization programs,
SMC tests simply do not provide a timely, viable and cost-
effective solution. There is generally insufficient material
available in the required coarser fragment sizes, typically
between 22.4 and 13.2 mm for SMC tests, to perform such
tests. For example, Bond testing typically requires at least
5kg of –3.35 mm material.
Application of HIT in Orebody Hardness Domaining Using
Exploration Samples
T Kojovic
SimSAGe Pty Ltd, Australia
C Bucknell, A Lam,
Brisbane Met Lab, Australia
ABSTRACT: One of the challenges in orebody domaining in early exploration stage characterization programs,
is availability of meaningful metallurgical data to target exploration drilling on prospects with a higher confidence
of return. The HIT device has been successfully deployed in early metallurgical testing programs globally to
help focus early resource definition and progress project development. During drilling programs however, access
to larger sample fragments for ore hardness testing, especially related to parameters relevant to crushing and
SAG/AG mill grinding, is generally not possible. To this end, an experimental study has been initiated at
the Brisbane Metallurgical Laboratory in Australia to understand if HIT testing on –2 mm fragments could
provide a solution. The proof-of-concept trial focused on 7 distinct rock samples selected to have a wide range
of hardness ranging from 30 to 330, as defined by the well-known JKDWT Axb index. The standard HIT test
protocol was modified to suit the small fragment constraint, and a wide range of test parameters was investigated
aiming to find the most viable option to estimate the Axb index from tests on an unconfined bed of narrowly
sized fragments below 2 mm. The preliminary results indicate that it is possible to reliably estimate the Axb
index from testing less than 15g of the same material below 2 mm using the modified HIT test. This paper
describes the initial trial and the results obtained for standard and small fragment HIT tests.
INTRODUCTION
The mining industry has for the longest time been testing
ore hardness requiring significant investment in cost and
time, typically Bond ball mill Work Index and SMC test ® /
JKDWT Axb (Bond, 1961 Morrell, 2004). The Axb index
has become well known in the mining industry as a reli-
able measure of ore hardness in impact or crushing, evident
in the numerous case studies reported at mining confer-
ences since the late 1980s. Experimental determination of
Axb using the above devices/tests requires samples, with
sufficient mass, to be sent to designated laboratories, reg-
istered to conduct such tests. This protocol is accepted for
bankable and commercial testing, where material charac-
terisation data is used in conjunction with machine specific
data in modelling and simulation, and power-based calcu-
lations. However, for geometallurgical or orebody domain-
ing in early exploration stage characterization programs,
SMC tests simply do not provide a timely, viable and cost-
effective solution. There is generally insufficient material
available in the required coarser fragment sizes, typically
between 22.4 and 13.2 mm for SMC tests, to perform such
tests. For example, Bond testing typically requires at least
5kg of –3.35 mm material.