XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 1201
2022). Tellurium concentrates are produced from mines
at Dashuigou and Majiagou in China from predominantly
bismuth telluride ore (Deng, 2009) and at Kankberg in
Sweden from gold telluride ore (Voigt, 2018 Voigt &
Bradley, 2020). These operations utilise flotation as the pri-
mary recovery process for tellurides followed by a leaching
process to produce a tellurium concentrate (Deng, 2009
Voigt &Bradley, 2020).
The supply of tellurium is clearly dependent on the
production of copper. The global sources of tellurium are
not well defined as it is mostly a byproduct of other metal
deposits. This is compounded by the fact that tellurium
is rarely included in standard assay suites for current and
future orebodies. Gold-telluride deposits represent a poten-
tial source of tellurium as current operations are recovering
gold but few recover the associated tellurium (Goldfarb et
al., 2017).
The production of tellurium from gold telluride ores
on a commercial scale has only occurred in a very small
number of operations around the world, the most notable
being Vatukoula in Fiji (Ellis &Deschênes, 2016). The
Emperor Mine in Vatukoula, Fiji developed a method to
commercially produce tellurium metal via leaching of a
high grade gold telluride flotation concentrate (Cornwall
&Hisshion, 1976). This circuit operated over a five year
period from 1976 to 1980 (Green, 2009).
The Golden Mile deposit in Western Australia is the
largest Archaean orogenic lode gold system in the world
(Bateman &Hagemann, 2004 Shackleton et al., 2003).
Gold in the deposit is mostly native gold in silicates and
sulphides (70–75%), gold-silver tellurides (20%) with the
remaining 5–10% occurring as “invisible gold” (Shackleton
et al., 2003). Currently gold is extracted but not tellurium.
This presents an opportunity to examine co-extraction of
gold and tellurium for the same environmental footprint.
PROCESSING OPTIONS
The successful separation of gold tellurides from other min-
erals in gold ores has been an ambition for many metallur-
gists. The incentive for this lies not just in the added value
of a tellurium byproduct but in the gold leaching process
itself. Gold telluride minerals require specialist leaching
conditions when compared with free milling gold ores. An
oxidative pretreatment stage that includes fine grinding,
high pH, roasting or pressure oxidation is usually required
prior to leaching with cyanide (Dyer et al., 2017 Ellis &
Deschênes, 2016).
If a low tonnage telluride concentrate can be separated
from the main ore stream, the remaining gold ore can be
treated using more conventional, and more cost effective,
gold leaching routes. For example, the leaching of sulphide
concentrate from Golden Mile ores necessitates the use
of pH12 and potable water (Dyer et al., 2017). Locally
sourced water is hypersaline and unsuitable for leaching at
the required pH levels necessitating the additional cost of
potable water. If a telluride concentrate can be produced,
the remainder of the sulphide concentrate can be leached at
lower pH using hypersaline water.
The production of a telluride concentrate also presents
the opportunity to recover tellurium during the leaching
process instead of it reporting to tailings. By capturing tel-
lurium in a concentrated stream, it creates a viable oppor-
tunity to recover tellurium thereby adding value to existing
operations. Two processing routes examining separation of
tellurides via flotation are presented here.
Grinding and Gravity Circuit
When designing grinding circuits, the properties and min-
eralogy of the telluride minerals and the orebody needs to
be considered. The main mechanism for the deposition of
primary telluride minerals in base and precious metal ores is
hydrothermal (Hayes et al., 2013 Missen et al., 2020). This
results in microfracture infill, vein formation and crystalli-
sation along grain boundaries (Clout et al., 1990 Hayes et
al., 2013 Liu et al., 2013). Often the outcome is complex
and fine grained telluride mineralisation.
It would be expected that fine grinding would be
required to achieve liberation, however telluride minerals
are brittle and tend to slime in grinding circuits (Ellis &
Deschênes, 2016 Johnston, 1933). This is seen in labo-
ratory test work conducted on Kalgoorlie ores where up
to 40% of the tellurium was finer than 5 microns for a
feed size of 150 microns (p80) (Weller et al., 1998). The
Emperor Mine in Fiji produced a flotation feed size of 55
per cent minus 74 micron via a rod-ball mill circuit when
operating a telluride flotation circuit (Colbert, 1980). No
data is given for the proportion of fine tellurium generated
by the grinding circuit.
The two circuit options presented in this paper include
a primary milling and gravity circuit. These are assumed to
produce an identical feed for each circuit. The feed prepa-
ration circuit would be optimised to suit the requirements
for the ore, the operating conditions on site and the desired
throughput. Consideration would be given to reducing the
generation of telluride slime material via choice of mill type
and classification system.
The gravity circuit is designed to remove gravity recov-
erable gold from the circulating load of the grinding circuit
2022). Tellurium concentrates are produced from mines
at Dashuigou and Majiagou in China from predominantly
bismuth telluride ore (Deng, 2009) and at Kankberg in
Sweden from gold telluride ore (Voigt, 2018 Voigt &
Bradley, 2020). These operations utilise flotation as the pri-
mary recovery process for tellurides followed by a leaching
process to produce a tellurium concentrate (Deng, 2009
Voigt &Bradley, 2020).
The supply of tellurium is clearly dependent on the
production of copper. The global sources of tellurium are
not well defined as it is mostly a byproduct of other metal
deposits. This is compounded by the fact that tellurium
is rarely included in standard assay suites for current and
future orebodies. Gold-telluride deposits represent a poten-
tial source of tellurium as current operations are recovering
gold but few recover the associated tellurium (Goldfarb et
al., 2017).
The production of tellurium from gold telluride ores
on a commercial scale has only occurred in a very small
number of operations around the world, the most notable
being Vatukoula in Fiji (Ellis &Deschênes, 2016). The
Emperor Mine in Vatukoula, Fiji developed a method to
commercially produce tellurium metal via leaching of a
high grade gold telluride flotation concentrate (Cornwall
&Hisshion, 1976). This circuit operated over a five year
period from 1976 to 1980 (Green, 2009).
The Golden Mile deposit in Western Australia is the
largest Archaean orogenic lode gold system in the world
(Bateman &Hagemann, 2004 Shackleton et al., 2003).
Gold in the deposit is mostly native gold in silicates and
sulphides (70–75%), gold-silver tellurides (20%) with the
remaining 5–10% occurring as “invisible gold” (Shackleton
et al., 2003). Currently gold is extracted but not tellurium.
This presents an opportunity to examine co-extraction of
gold and tellurium for the same environmental footprint.
PROCESSING OPTIONS
The successful separation of gold tellurides from other min-
erals in gold ores has been an ambition for many metallur-
gists. The incentive for this lies not just in the added value
of a tellurium byproduct but in the gold leaching process
itself. Gold telluride minerals require specialist leaching
conditions when compared with free milling gold ores. An
oxidative pretreatment stage that includes fine grinding,
high pH, roasting or pressure oxidation is usually required
prior to leaching with cyanide (Dyer et al., 2017 Ellis &
Deschênes, 2016).
If a low tonnage telluride concentrate can be separated
from the main ore stream, the remaining gold ore can be
treated using more conventional, and more cost effective,
gold leaching routes. For example, the leaching of sulphide
concentrate from Golden Mile ores necessitates the use
of pH12 and potable water (Dyer et al., 2017). Locally
sourced water is hypersaline and unsuitable for leaching at
the required pH levels necessitating the additional cost of
potable water. If a telluride concentrate can be produced,
the remainder of the sulphide concentrate can be leached at
lower pH using hypersaline water.
The production of a telluride concentrate also presents
the opportunity to recover tellurium during the leaching
process instead of it reporting to tailings. By capturing tel-
lurium in a concentrated stream, it creates a viable oppor-
tunity to recover tellurium thereby adding value to existing
operations. Two processing routes examining separation of
tellurides via flotation are presented here.
Grinding and Gravity Circuit
When designing grinding circuits, the properties and min-
eralogy of the telluride minerals and the orebody needs to
be considered. The main mechanism for the deposition of
primary telluride minerals in base and precious metal ores is
hydrothermal (Hayes et al., 2013 Missen et al., 2020). This
results in microfracture infill, vein formation and crystalli-
sation along grain boundaries (Clout et al., 1990 Hayes et
al., 2013 Liu et al., 2013). Often the outcome is complex
and fine grained telluride mineralisation.
It would be expected that fine grinding would be
required to achieve liberation, however telluride minerals
are brittle and tend to slime in grinding circuits (Ellis &
Deschênes, 2016 Johnston, 1933). This is seen in labo-
ratory test work conducted on Kalgoorlie ores where up
to 40% of the tellurium was finer than 5 microns for a
feed size of 150 microns (p80) (Weller et al., 1998). The
Emperor Mine in Fiji produced a flotation feed size of 55
per cent minus 74 micron via a rod-ball mill circuit when
operating a telluride flotation circuit (Colbert, 1980). No
data is given for the proportion of fine tellurium generated
by the grinding circuit.
The two circuit options presented in this paper include
a primary milling and gravity circuit. These are assumed to
produce an identical feed for each circuit. The feed prepa-
ration circuit would be optimised to suit the requirements
for the ore, the operating conditions on site and the desired
throughput. Consideration would be given to reducing the
generation of telluride slime material via choice of mill type
and classification system.
The gravity circuit is designed to remove gravity recov-
erable gold from the circulating load of the grinding circuit