XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 117
• Mass mining tends to have a low operating cost, due
to the volumes moved
• High resolution mining, where practical and using
existing equipment, will mostly be more expensive
• Ingrained corporate behavior, whereby Key
Performance Indicators (KPIs) often focus on tons
of material movement, which can often be associ-
ated with increased dilution to the detriment of
comminution, beneficiation and other downstream
processes.
In some instances, targeted mining is commonly under-
taken. In small scale underground stoping, ore structures
are often chased by the mining method and the only waste
taken is due to the minimum size of stopes, or excavations
required for safe and efficient operation. Another common
example is the use of longwall shearers in the coal industry.
In this form of mining the longwall device advances into
the seam and the ground surrounding the mined-out seam
is allowed to close in a controlled manner.
Given the attraction of minimizing waste mining, sev-
eral other techniques have been proposed for this purpose.
Some of the methods include:
• Reef mining and mechanized cutting
• Placer Dome – mining method for steeply dipping
ore bodies
• ROES
• SABRE.
The main thrust for mechanical cutting has been to apply
undercut or tensile breakage where possible. Sandvik have
pursued the reef miner concept through the MN3300
(International Mining, 2022), which is able to cut reef as
thin as 1.5m and with a 30degree incline. The MX650,
Sifferlinger et al. (2017), is designed for a wider application
envelope in terms of ore presentation and rate, but as with
the MN3300, both use roller disc undercutting as the exca-
vation mechanism. Komatsu offer a development of the
Oscillating Disc Cutter, which is now incorporated within
the DynaMiner system, Mining3 (2024). The other major
OEM in this area is Epiroc with their Mobile Miner, which
is offered in a range of configurations to suit the required
duty.
Other forms of selective mechanized mining have
also been examined incorporated for remote deployment.
Work from the 1980s by Placer Dome (Hames et al., 2005)
examined how a rock cutting device could be deployed in
steep dipping ore bodies, with the cutting element lowered
down through the orebody.
The CSIRO ROES, Mining3, (2017), system uses
remote, automated horizontal drilling and blasting to
selectively excavate blocks of ore. Also, as a development of
the original concept, there is now a plan to examine how
such technology could be used to create an underground
leach reactor, particularly in low grade ore.
As an alternative to mechanical cutting, the SABRE
system (Orano, 2021) uses high pressure water jet cutting
and air-lifting of slurry to excavate and transport mate-
rial to the surface. It is a selective method which does not
require physical entry. In 2021 it was reported that a five
year program had successfully been completed, but opera-
tional deployment since that date is unknown.
In terms of highly selective mining methods, some
operational examples can be seen in Cameco uranium
operations at Cigar Lake and McArthur River. Cigar Lake
uses jet boring which relies on freezing the ground and
then using high pressure water to loosen and slurry the ore,
which is then pumped to the surface. McArthur River take
a different approach and use a mechanical raise borer. From
a chamber directly above the orebody a series of overlap-
ping raise bore holes are used to cut the ore which flows
down for extraction via remote operated LHD.
It is clear that in the aforementioned examples of highly
selective mining methods, the orebody geometry and pre-
sentation are the main controls over the ability to deploy,
with scalability another major consideration.
Into the future, pursuit of orebodies will inevitably
drive the need for deep underground mining, with all
the associated considerations, i.e., ventilation (inc. refrig-
eration), rock mass stress conditions, access of personnel,
materials handling etc. Such factors all have a major impact
on the energy requirements and the role of comminution is
critical, both in the size reduction of the rock mass, but also
in generating a particle size which can ease transport from
deep levels to the surface. Aspects such as hydraulic hoist-
ing, with the option of energy recovery, have often been
discussed, but to make this a reality, the particle size distri-
bution must be suitable and this would require a specific
comminution solution.
Preconcentration
Preconcentration, or the ability to reject waste material at a
coarse size and therefore reduce the comminution require-
ment, for the same metal output, has received significant
interest, particularly over the last 20 years’. The deployment
point for preconcentration within the overall mine-process-
ing system is dependent on many factors, with the orebody
presentation being paramount. The most commonly cited
deployment conditions are:
• In-bucket
• In-truck
• Mass mining tends to have a low operating cost, due
to the volumes moved
• High resolution mining, where practical and using
existing equipment, will mostly be more expensive
• Ingrained corporate behavior, whereby Key
Performance Indicators (KPIs) often focus on tons
of material movement, which can often be associ-
ated with increased dilution to the detriment of
comminution, beneficiation and other downstream
processes.
In some instances, targeted mining is commonly under-
taken. In small scale underground stoping, ore structures
are often chased by the mining method and the only waste
taken is due to the minimum size of stopes, or excavations
required for safe and efficient operation. Another common
example is the use of longwall shearers in the coal industry.
In this form of mining the longwall device advances into
the seam and the ground surrounding the mined-out seam
is allowed to close in a controlled manner.
Given the attraction of minimizing waste mining, sev-
eral other techniques have been proposed for this purpose.
Some of the methods include:
• Reef mining and mechanized cutting
• Placer Dome – mining method for steeply dipping
ore bodies
• ROES
• SABRE.
The main thrust for mechanical cutting has been to apply
undercut or tensile breakage where possible. Sandvik have
pursued the reef miner concept through the MN3300
(International Mining, 2022), which is able to cut reef as
thin as 1.5m and with a 30degree incline. The MX650,
Sifferlinger et al. (2017), is designed for a wider application
envelope in terms of ore presentation and rate, but as with
the MN3300, both use roller disc undercutting as the exca-
vation mechanism. Komatsu offer a development of the
Oscillating Disc Cutter, which is now incorporated within
the DynaMiner system, Mining3 (2024). The other major
OEM in this area is Epiroc with their Mobile Miner, which
is offered in a range of configurations to suit the required
duty.
Other forms of selective mechanized mining have
also been examined incorporated for remote deployment.
Work from the 1980s by Placer Dome (Hames et al., 2005)
examined how a rock cutting device could be deployed in
steep dipping ore bodies, with the cutting element lowered
down through the orebody.
The CSIRO ROES, Mining3, (2017), system uses
remote, automated horizontal drilling and blasting to
selectively excavate blocks of ore. Also, as a development of
the original concept, there is now a plan to examine how
such technology could be used to create an underground
leach reactor, particularly in low grade ore.
As an alternative to mechanical cutting, the SABRE
system (Orano, 2021) uses high pressure water jet cutting
and air-lifting of slurry to excavate and transport mate-
rial to the surface. It is a selective method which does not
require physical entry. In 2021 it was reported that a five
year program had successfully been completed, but opera-
tional deployment since that date is unknown.
In terms of highly selective mining methods, some
operational examples can be seen in Cameco uranium
operations at Cigar Lake and McArthur River. Cigar Lake
uses jet boring which relies on freezing the ground and
then using high pressure water to loosen and slurry the ore,
which is then pumped to the surface. McArthur River take
a different approach and use a mechanical raise borer. From
a chamber directly above the orebody a series of overlap-
ping raise bore holes are used to cut the ore which flows
down for extraction via remote operated LHD.
It is clear that in the aforementioned examples of highly
selective mining methods, the orebody geometry and pre-
sentation are the main controls over the ability to deploy,
with scalability another major consideration.
Into the future, pursuit of orebodies will inevitably
drive the need for deep underground mining, with all
the associated considerations, i.e., ventilation (inc. refrig-
eration), rock mass stress conditions, access of personnel,
materials handling etc. Such factors all have a major impact
on the energy requirements and the role of comminution is
critical, both in the size reduction of the rock mass, but also
in generating a particle size which can ease transport from
deep levels to the surface. Aspects such as hydraulic hoist-
ing, with the option of energy recovery, have often been
discussed, but to make this a reality, the particle size distri-
bution must be suitable and this would require a specific
comminution solution.
Preconcentration
Preconcentration, or the ability to reject waste material at a
coarse size and therefore reduce the comminution require-
ment, for the same metal output, has received significant
interest, particularly over the last 20 years’. The deployment
point for preconcentration within the overall mine-process-
ing system is dependent on many factors, with the orebody
presentation being paramount. The most commonly cited
deployment conditions are:
• In-bucket
• In-truck