CONTINUOUS CUTTING
for productivity or safety reasons ,” Grothen said . “ The reality is it is a lot easier to automate a mechanised process than it is a manual one like drill and blast . Step one of this process is getting mining companies comfortable with mechanised boring and step two is automating the process .”
Home added : “ This realisation also stretches to an understanding that if mining companies want to reach deeper mines in a reduced timeframe , they must adopt mechanical excavation .”
Some forward-thinking companies are already embracing this potential , with Home reflecting on one specific study project the company has been working on for over a year .
“ In this instance , they have engaged a contractor as well as us to scope out a mine development plan ,” he said . “ On top of that , they are designing the whole process to leverage mechanical excavation , meaning they will benefit from all the advantages that come with this technology .”
While technologies outside of the traditional TBM-style of machine continue to be tested and considered in a mine development setup , Robbins remains committed to its vision , according to Home .
“ We ’ re convinced that full-face engagement is the only way to go in a mine development scenario ,” he said . “ That conviction hasn ’ t changed from Day One .”
Komatsu out to find the ‘ perfect trifecta ’
Three years after arriving on site at the Garson mine in Sudbury , Canada , Komatsu ’ s MC51 machine is now awaiting a window where the machine can be demobilised .
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 nominal 5 x 5 m profile , according to Komatsu . The machine is also able to cut within 50 mm of plan , with the resultant excavations exhibiting high tunnel quality and a reduction of over break . After the machine cuts the rock – on average 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 has been 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 Newmont ’ s Cadia copper-gold operation in New
South Wales , and Hillgrove Resources ’ Kanmantoo copper project in South Australia . The latter involved the establishment of an underground decline .
The MC51 has also faced up to the civil construction test , with one unit having worked in New South Wales , completing some 400 m of development work in soft-rock conditions . This deployment saw modifications to the existing MC51 design where an onboard conveyor was able to load a 35-t payload truck .
The biggest MC51 news is that after facing up to cutting the Sudbury rock , there are now two MC51s ready to be deployed in short order to new sites .
The three-stages of the trial that took place over the last three years at Garson involved the excavation of a 30 m straight advance ( Stage 1 ), 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 , Stage 2 ), and a 70- m development stretch that included a 25 m radius curve ( turnout ) at increasing grades ( Stage 3 ).
IM reported on the first two stages of the project last year , with Stage 3 having since been carried out successfully .
There was talk in this same feature last year of using the MC51 to develop a tunnel at the 340 level up to 200 level . This could have represented some 300 m of development in total , however both Komatsu and Vale agreed to end the trial due to challenging ground conditions ( tough on cutter discs ). The companies still plan to continue their collaboration around mechanical cutting .
Colin Wade , Sales and Service Manager for Mechanical Hard Rock Cutting Systems at Komatsu Mining , told IM : “ We ended up cutting in ore with a small sliver of the mini McConnell orebody towards the end of our time at Garson , which gave us a glimpse into the sort of rates we could achieve cutting in ore as opposed to waste – where the machine has mostly been positioned .
“ Having then moved into a different area , experienced some difficulty with the ground conditions during the initial preparation stage , taken the production plans of the mine into account and reflected on the progress made over the space of the last three years – improving cutter reliability , software , user operation , etc – we decided to curtail the work on the tunnel pretty early on after cutting commenced .”
The progress made over this period is easy to comprehend when Wade reflects on the development of 10-20 different cutter disc combinations and techniques , a reinforcement of the machine ’ s exciter base , new measures to protect cylinders on the machine , adding a remote operating station underground , creating the foundations for a data acquisition platform , etc .
“ We learned a lot in the civils application , too , where cutting wasn ’ t the real limitation on the machine , but the Garson project has been invaluable ,” Wade said . “ We ’ re convinced if we can cut this Sudbury rock , we can cut any type of rock . It is now a question of how we can apply this knowledge to assess commercial cutting rates in commercial applications .”
This shift has also led to Komatsu further engaging with the mine development contracting community , acknowledging that it needs the Komatsu local support , contracting partner and ‘ open ’ mining company to facilitate a successful commercial MC51 operation .
“ We ’ re not operators ; it is not our core business ,” Wade said . “ As a result , we ’ re now going through the process of working with contractors to find this perfect trifecta .”
Wade couldn ’ t say a lot more about this process , but he did reflect on several opportunities Komatsu was pursuing in both North America and Australia where a support network , contracting partner and mining company alliance could soon form .
More broadly , he saw strong future market adoption for mechanical cutting technologies .
“ As this world becomes more and more conscious of ESG , sustainability and community … there are going to be times where you simply must take people out of harm ’ s way ,” Wade said . “ With traditional drill and blast operations , you will get to a plateau in terms of automation to a point where you need a fully autonomous machine . The MC51 represents such a machine .”
Sandvik MX650 Mk2 in the works
Sandvik Mining and Rock Solutions continues to work with a consortium of major mining companies , through the Canada Mining Innovation Council ( CMIC ), to develop the second generation of its own mechanical rock excavation machine , the MX650 .
This is leveraging the experience from developing the first generation machine , along with extensive testing , Sandvik says . The loading and bolting operations that are part of the mechanised process are just some of the elements under evaluation .
The MX650 has been designed for mine developments in hard rock in excavations from 4 x 4 m to 5.1 x 7 m .
The first iteration of the MX650 was put through its paces during several test programs over the past few years at WOLFRAM ’ s Mittersill tungsten mine in Austria , which is owned by Sandvik Group . Boliden , LKAB and Agnico Eagle Mines were among a list of mining companies to have witnessed some of this testing , with these
58 International Mining | NOVEMBER / DECEMBER 2024