CONTINUOUS CUTTING AND RAPID DEVELOPMENT
The Sandvik MX650
uses roller-disc
undercutting technology
and is primarily designed for
mine development
in excavations from 4
x 4 m to 5 x 5 m
feasibility and returns of projects
constructed by our future clients. The
technology will provide them with value through
increased productivity, competitive cost, quality
excavations and more industrialised safe
operation and enterprise risk,” he said.
Master Tunnelling already has a positive track
record of horizontal mechanised cutting. Its
Master Drilling parent company previously
carried out a horizontal raisebore drive of 180 m
length and 4.5 m diameter in a kimberlite pipe at
Petra Diamonds’ Cullinan mine in South Africa.
Speaking of Petra, the diamond miner has
agreed to trial Sandvik’s MX650 hard-rock cutting
technology at the Finsch mine in South Africa in
the future.
Sandvik has previously said the machine,
which uses roller-disc undercutting technology, is
primarily designed for mine development in
excavations from 4 x 4 m to 5 x 5 m. The
assembly and functional testing of the MX650
was completed by the end of March 2017,
followed by a first test operation at the
company's tungsten mine in Mittersill, Austria.
The trial at Finsch is expected to take place
next year, but Sandvik is also in discussions with
Goldcorp that could see the machine trialled at
the Canada-based company’s Musselwhite
operation in Ontario.
One of the Sandvik’s rivals in this space –
Komatsu Mining (previously Joy Global) – has
made some headway on a hard-rock cutting
technology of its own.
Komatsu and Mining3’s DynaCut HRCM
technology is used to selectively mine hard-rock
ore and take advantage of natural structural
features to break the rock.
Back in 2016 at MinExpo, the company
introduced a prototype machine, which
incorporated the DynaCut rock-breaking
technology and years of R&D geared towards
finding improvements to the conventional drill
and blast process.
DynaCut combines an undercutting approach
(exploiting tensile and shear failure mechanisms)
with a high-frequency dynamic motion. The
method requires much lower forces than those
associated with conventional roller disc cutting
and can effectively cut rock well beyond the
strength limits of pick-based tools, according to
Komatsu and Mining3.
“The prototype machine has two key parts:
the DynaCut disc that oscillates, which is
mounted to a smart boom and a compact,
lightweight, mobile mining machine which,
42 International Mining | DECEMBER 2018
A similar method of hard-rock cutting is used
on its Rock Straight System, a fully-mechanised
longwall system adopted to hard-rock
conditions for continuous mining of low-
seam deposits.
The system, developed in
partnership with KGHM, combines the
use of Cat’s hard-rock shearer (Hard Rock
Miner HRM220), hard-rock chain
conveyor (Hard Rock Conveyor HRC30)
together, form
part of a continuous
cutting system. It can cut in
any direction and is not limited by the availability
of a free edge, allowing for the development of
flexible, accurate tunnel profiles of any shape,”
the two companies said.
Used in conjunction with haulage devices and
mobile roof bolters, the prototype can make up
part of a hard-rock continuous mining system.
Back at MinExpo, the companies said the
technology was being trialled at Newcrest
Mining’s Cadia East gold mine in New South
Wales, Australia.
Caterpillar, too, has developments in this
space, with its RH55 Rock Header and the Rock
Straight System.
Late last year, the company confirmed the
RH55 was being trialled in an Hagerbach Test
Gallery in Switzerland. The RH55 is designed for
fast, mechanised roadway development in
underground hard-rock mines to help mining
companies accelerate return on investment.
The prototype validation process has included
gathering detailed input from Caterpillar
customers in many different mining districts
around the world. As of December 2017, the
engineering team was still tuning performance
objectives and gearing up to test in different
scenarios.
The Rock Header uses Caterpillar’s Activated
Undercutting Technology
for hard-rock cutting. The
design of the cutting head
enables the picks to
attack the rock from an
optimum angle to exploit
its tensile strength, which
is only 10 to 20% of its
compressive strength. Cat
says. The activation
movement optimises
velocity, momentum and
impact of each pick –
while moving the pick
away quickly, minimising
wear and heating. The
result is reduced energy
consumption and
replacement cost of
cutting tools.
and hydraulic roof support (Hard Rock
Roof Support HRS1220).
Again, it features Activated Undercutting
Technology and has been “specifically designed
for the extraction of bedded hard-rock deposits
(eg platinum, copper, gold)”, Cat says. It aims to
provide economical cutting in the mining of thin
seams – 1.3 to 2 m heights – and narrow veins,
especially when selective mining of ore is
required.
Not breaking with convention
Mechanised cutting might not suit all projects
when it comes to accelerating mine development
and production.
At the Centre for Excellence in Mining
Innovation (CEMI) in Sudbury, Ontario, there is a
Rapid Mine Development project (RMDP) looking
to, eventually, automate the drill and blast
process and improve the advance rates currently
seen in the industry.
CEMI President Doug Morrison told IM:
“Cutting machines have always done very well in
civil engineering projects where the length of
tunnel is very long. Yet, in underground mines, it
is typically much shorter tunnels, with the
geology of the orebody making the layout of the
mine more complex.”
OEMs are producing mechanised cutting
technology to deal with such complexities, but
their ability to quickly and accurately excavate
The RH55, here being trialled
in a Hagerbach Test Gallery in
Switzerland, is designed for
fast, mechanised roadway
development in underground
hard-rock mines