CONTINUOUS CUTTING looking for ,” Grothen said . “ And , of course , all the mines want to excavate with tight turning radiuses . The MDM was designed around a development drift with conveyors , but we are also looking at what we could offer for excavations on curves .
“ Another consideration is also quick tramming for relocating the machine from one heading to the next .”
In its current form , the MDM5000 still has plenty of potential applications for the mining sector , Grothen says .
“ People like TBMs where they can excavate quickly and handle the material ,” he said . “ Some of the challenges associated with using roadheaders and partial face cutting technology are tied to sacrificing speed for mobility and potentially having issues with material handling . With the MDM5000 , we ’ re looking to give them the best of both worlds by being able to attack the entirety of the face as much as possible while having a proven material handling philosophy .”
Mining companies are more readily familiarising themselves with MRE options at the early stages of projects , he added , with Robbins having been called upon for input on studies relating to TBM and drill & blast tradeoffs .
Home and Grothen have also witnessed more interest from the contractor side of the mining business , with several companies looking to understand the process and the systems-based approach to mine development with TBMs .
“ Cutting technology is , for sure , important , but you also need to consider the muck removal , the ground support and logistics ,” Grothen said . “ You have to manage this system and have a scalable technology in play where no one element becomes a bottleneck .”
The Robbins MDM5000 is capable of cutting hard rock up to 200 MPa UCS while creating a flat invert for access by rubber-tyred vehicles
and bolting section is up front , followed by the transformer and 300 m capacity water and electrical reels on the third unit , and a 14 cu . m capacity storage bunker and discharge system on the fourth unit .
The units are also equipped with conveyors that transport the mucked material along the machine .
Having initially been tested in a quarry in Italy in soft rock in 2018 , the MTB made the trip back to South Africa to start work on a 1.4-km project at Northam Platinum ’ s Eland platinum group metals operation , in harder rock . This project was terminated in March 2020 due to the COVID-19 pandemic .
The MTB was then deployed on the Sandsloot Exploration Decline at Anglo American Platinum ’ s Mogalakwena PGM mine , in South Africa , as part of a turnkey contract with the mining company .
This work was ultimately cut short , with Koos Jordaan , Master Drilling Director telling IM that the company was working through all the learnings with a “ rebuilt and reworked ” MTB likely to be ready for deployments in 2024 .
“ The elements that are holding back the MTB are not necessarily tied to the machine itself ; it is everything that needs to be done with it ,” he said . “ As a contractor , we are looking at working simplicity , reliability and how the whole system works so we can execute the job efficiently and safely .
“ One of the major learnings we had was the need to concurrently carry the services and engineering with you on a decline . With the next iteration , we are expecting better and more consistent performance than we had at Mogalakwena .”
A second-generation MTB is also in the works in partnership with a mining company . This is likely to cater to 6.5-m diameter tunnels and be ideally matched to establishing twin declines .
A square cutter concept for flat roof , side walls and floor – instead of the circular excavations offered by the existing MTB – is also in the Master Drilling innovation pipeline , as are developments around “ cut & break ” technology and reef mining .
Outside of collaborations with mining companies , Master Drilling is opening up to the equipment makers themselves in this sector , with personnel having visited several test sites over the last 12 months to scope out potential partnerships and projects .
“ We have significant experience as both technology maker and contractors ,” Jordaan said . “ You only have to look at our record in the raiseboring space to realise how effectively , efficiently and safely we can cut hard rock over significant distances .
“ We believe we have something unique to offer the sector .” IM
Taking a systems approach
Master Drilling Group has also been looking to dispel the associations of inflexibility often levelled at TBM companies from the mining community .
Its Mobile Tunnel Borer ( MTB ) is equipped with a full-face cutter head with disc cutters adapted from traditional TBMs . Unlike these traditional machines , it is designed to work both on inclines and declines , with the first-generation machine having the ability to navigate around corners and construct 5.5-m diameter decline access tunnels .
The MTB is made up of four track-mounted units containing various parts – the cutter head
The MTB is designed to work on both inclines and declines , with the first generation machine having the ability to navigate around corners and construct 5.5 m diameter decline access tunnels
NOVEMBER / DECEMBER 2023 | International Mining 45