CONTINUOUS CUTTING
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 . Haugen and several of her colleagues witnessed the latest testing of the first-generation prototype at Mittersill , with the mining company and fellow Sweden-based miner LKAB now part of a consortium , led by CMIC , looking at developing a second generation MX650 .
Arne Lewis , Vice President of Hard Rock Continuous Mining at Sandvik Mining and Rock Solutions , told IM last year that some of the ‘ lessons learnt ’ from testing MX650 1.0 being factored into the second generation MX650 are tied to the loading and bolting operations that are part of the mechanised process .
Asked why the company was backing this CMIC-led project , Haugen said : “ For me , I think undercutting is the most energy-efficient way of cutting the rock and achieving the square cross section with the flexibility required .
“ The fact that we believe in this cutting technology and there was a consortium open to help develop this machine made it an easy decision to invest and get this machine to an adequate technology readiness level .”
She added : “ We at Boliden want to be at the forefront and lead this technology development . We want to learn as much as we can – both about capabilities and shortcomings – and see how the machine will behave and how we could potentially operate it .”
Haugen says no specific projects have been identified where the MX650 could potentially be deployed , but the learnings from testing MX650 2.0 could allow Boliden to screen for suitable applications across its project portfolio .
Then there is the potential operation of such a machine to consider .
“ This is the big question we are discussing as we work on this ,” Haugen said . “ Many years ago , Boliden had its own in-house mine development team – like what LKAB had with Bergteamet – who had the skill set to carry out such excavations . We are now weighing up if we could set up an internal team to conduct such work , if we use a contractor , or if the OEM could come in to operate the machine .
“ This is something that will be very important for the success of any project involving these new technologies .”
Mobile Mine ( r ) of the future
When it comes to mining-specific mechanical rock excavation technology , there are few OEMs that can compete with Epiroc in the commitment stakes .
The Sweden-based company launched the Mobile Miner family back in 2017 under the
auspices of Atlas Copco . Upon launch , it invested in the development of three units : the 22H , 40V and 55V .
In the years that have passed , this has been refined into a two-product family featuring the 22H and the 40V – both of which have been designed for specific mining methods and constraints .
These Mobile Miners , consist of two major parts : the rear “ power unit ” and the front “ miner ”.
The miner incorporates the cutterhead and everything needed to excavate ore ; the power unit contains all the motors , pumps , ground support and control systems . Each unit is roughly 10 m in length , with the two parts connected by an articulation joint to improve manoeuvrability for negotiation of tight corners as well as minimise vibration in the operator ’ s cab .
The largest Mobile Miner is the 40V , which is typically used in small-to-medium-sized tunnels and cut-and-fill mining requiring 4 m x 4 m advances .
The V indicates the cutter head is placed vertically – as opposed to the H of the 22H , placed horizontally – with the stated advance rate of the machine being 10-15 m / d depending on the rock type .
Reminiscent of a traditional TBM , the first 40V was scheduled to be deployed at Hecla Mining ’ s Lucky Friday mine in Idaho , USA , after extensive work by both Hecla and Epiroc to tailor the machine to the veins that would be mined at the seismically active operation . Yet , the successful application of a new mining method – Underhand Closed Bench – at the mine recently led to Hecla deciding against the machine ’ s use at Lucky Friday .
Around this time last year , discussions between Epiroc and Hecla continued about deploying the 40V at Greens Creek in Alaska , a Hecla-owned mine that primarily uses cut and fill , and drift and fill techniques , supplemented by longhole stoping where orebody geometry permits . This is different to the primary mining method of underhand stoping with paste backfill that Lucky Friday was leveraging and the 40V had been designed for .
This application of the 40V at Greens Creek
The Epiroc Mobile Miner 40V is currently in Sweden at Epiroc ’ s own test mine where interested mining companies have been visiting
was always hard to reconcile – due , in part , to the different mining method and ramp-only access offered by the operation – and the parties have since decided to look for an alternative site to test the machine .
Markus Eklind , Epiroc Global Business Line Manager – Mechanical Rock Excavation , told IM : “ Hecla and Epiroc remain committed to this project and , together , we are currently investigating potential partners that can get involved with the machine ’ s development and offer up a test site . We are focused on proving the technology on a continuous basis in a reallife operation .”
The machine is currently in Sweden at Epiroc ’ s own test mine where interested mining companies have been visiting .
“ I am optimistic that during 2024 we will be able to communicate something significant on this project ,” Eklind said .
When it comes to the 22H , Epiroc is also expecting a busy 2024 .
This machine – with certain adaptations – was previously tested at the Twickenham PGM mine in Limpopo Province , South Africa , where it advanced at over 10 m / d in 140-150 MPa UCS rock in a trial that was curtailed due to the mine being placed on care and maintenance . It is designed for low-seam or low-profile mining where tunnels as low as 2.2 m are required .
Eklind says the OEM continues to work with Anglo American as part of its FutureSmart Mining™ vision , with the 22H currently at Bentley Park , just outside of Johannesburg , South Africa , at a training facility owned by Murray & Roberts Cementation .
“ Together with Anglo American we are preparing for some tests involving mechanical rock cutting and preconditioning ,” Eklind said .
Speaking along these lines at the recent Bank of America 2023 Smart Mine 4.0 conference , Donovan Waller , Anglo American Group Head of Technology Development , said the company had been testing preconditioning ore technology
NOVEMBER / DECEMBER 2023 | International Mining