CONTINUOUS CUTTING
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 dimensions of the required excavation in this trial , with the machine development rates proving very competitive when compared with
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