CONTINUOUS CUTTING
application methods with microwaves over the past few years and the effect on in-situ ores in both underground and surface mines .
He said : “ We are currently testing a production cutter in a quarry and , if successful , we will install a first-generation microwave preconditioning system in a production environment at an Anglo American site in 2024 .” Outside of these two developments , Eklind was pleased to see more talk of MRE among the mining community .
“ From my perspective , any progress with MRE equipment benefits MRE in general ,” he said .
“ For us , the concept of the Mobile Miner fits very well into the mine of the future in that it is a continuous process , comes with no diesel emissions , no blast fumes , etc . That is why it is even more important to us to prove these are not just prototypes but are effective machines .
“ I don ’ t think there are doubts about the rock cutting ; we use traditional TBM technology and can predict penetration rates and wear on the tools as there are thousands of metres drilled with these steel discs every year . What we need to prove is the system , the availability and production rates , along with the required personnel to operate it .”
Komatsu MC51 on the up
Komatsu ’ s MC51 machine has already been tested at three mines to date , with the OEM having a bank of data and learnings to work from when it comes to new hard-rock applications .
The latest mining assignment is in Canada at Vale ’ s Garson mine in Sudbury , where the MC51 is working mainly in waste rock around the Mini McConnell orebody as part of the mechanical cutting demonstration within the CMIC Continuous Underground Mining project .
The MC51 leverages DynaCut technology , an undercutting disc technology for mechanical cutting . It has a cutter on a single , five-axis robotic boom that can profile any shape within a 5 x 5 m profile , according to Komatsu . The machine is also able to cut within 50 mm of plan , with the resultant excavations already exhibiting high tunnel quality and a reduction of over break .
After the machine cuts the rock – 200-250 MPa in the case of the rock in Sudbury – into consistently-sized small chunks , the material is gathered into the centre and conveyed to LHDs , trucks or external conveyors to be hauled away . At Garson , it is a 7-t payload Komatsu WX07 carrying out the mucking .
The result of more than 10 years of research and development , the MC51 is fully electric , outputting zero emissions . It also offers increased levels of automation , with the machine able to be operated remotely via line of sight .
Many of these functions have been tested in some form on previous assignments at Newcrest
Mining ’ s Cadia copper-gold operation , in New South Wales , and Hillgrove Resources ’ Kanmantoo copper project , in South Australia .
IM reported on progress in Canada at Garson last year , with Andy Charsley , Principal Mining Engineer at Vale , explaining some 30-40 m of development had been carried out with the machine in waste rock .
In the 12 months that have passed , further progress has been made on what is now a threestage R & D program due for completion by the end of the year .
“ We appear to have figured out many of the kinks that come with any R & D project like this ,” Charsley said . “ Both companies remain committed , and we continue to keep the other CMIC partners ( Glencore and Agnico Eagle Mines ) regularly informed on progress .”
Stage one – which has been completed – saw a 30 m straight advance excavated . This stage exhibited some understandable cutter disc and mechanical challenges .
This was followed by stage two – another 30 m of straight advance in a different area of the mine focused on improving cutter life and reducing the forces exerted on the exciter ( positioned behind the cutter ). This advance was deemed a success , with an increase in the size of the buttons on the cutter head ( each cutter is made up of 92 buttons ), a change in the cutting pattern and upgrades to the on-board positioning system addressing the issues experienced during stage one .
Stage three , which Vale and Komatsu are in the middle of , is even more dynamic , with a 70-m development stretch that includes a 25 m radius curve at increasing grades . Some of this development is also being carried out with operators situated in a remote cabin that will eventually be out of line of sight with the machine .
During this stage , the expectations are for each disc to exhibit a life of , on average , 6 m of development , with development averaging 0.35 m / h . Based on a seven-hour shift , this could see advances average at 2 m / shift .
Reviewing the progress to date at Garson , Colin Wade , Sales and Service Manager for Mechanical Hard Rock Cutting Systems at Komatsu Mining , said : “ The biggest thing we have gained an understanding of is that the rock conditions change drastically from one section to another . We started this trial with one cutter disc design and , more than 18 months in , we have 5-6 disc options , each of which has its own merits in certain applications .
“ This is critically important as the cutter wear is , typically , the driving factor in the cost model mining companies and contractors are looking at . It is all focused on getting the lowest cost per metre .”
Should Komatsu and Vale complete the circa- 130 m , three-stage development successfully , a bigger project could be up next in Sudbury .
Charsley said : “ Our next discussion is to develop this tunnel at the 340 level up to 200 level , which is 60-or-so metres below surface and already in Vale ’ s future production plans . This would represent some 300 m of development in total and , as we envision it , take us through the majority of 2024 .”
In Australia , meanwhile , a second MC51 is currently undergoing an “ engineering evaluation ” after completing the equivalent of 350 m of development work in a civils project in softer rock conditions ( averaging 50-80 MPa ) in New South Wales . This deployment saw modifications to the existing MC51 design to load a 30-t payload truck ( Komatsu HM300 ADT ). Wade said this saw Komatsu create a bolt-on extension conveyor that allows the material to be loaded directly and evenly into the truck .
This same machine is likely to head to another mining application in Australia following the engineering evaluation and minor upgrades .
For Charsley , he sees a bright future ahead for the MC51 in specific mining applications .
“ After two years of seeing it working at Garson , I am getting convinced that this machine is for place-change applications where you come in , do 6-7 m of development , change location and then start cutting again ,” he said . “ It ’ s not about pure speed in a straight heading like a TBM is designed for ; it is about offering flexible mechanical cutting for more complex areas of mine development .”
It shouldn ’ t be forgotten that Komatsu , through its Komatsu Cummins Chile Ltda subsidiary , is collaborating with Codelco on trialling a new tunnel excavation method using the OEM ’ s newly developed Mining Tunnel Boring Machine starting in 2024 at the Chuquicamata underground mine .
Wade was equally positive on the MC51 ’ s potential : “ We ’ re finding this machine to be very versatile . It is nimble enough to move through small spaces of a mine and change direction but is also able to cut large excavations in various conditions – changing cutter heads when encountering tough rock conditions or picking up the pace when the conditions allow .
“ To this point , we have deliberately focused on cutting as we don ’ t want the machine to lose that flexibility and nimbleness .”
This focus has been supported by the base machine ’ s reliability in the trials to date .
“ In the civils application in Australia , we were handling significant tonnage through the material handling system , which proved itself in terms of the dust management and material movement ,” Wade said . “ We were also able to cut different profiles to suit the various
International Mining | NOVEMBER / DECEMBER 2023