CONTINUOUS CUTTING
The larger stopes that Greens Creek offers will be beneficial for manoeuvring the 40V in and out of the areas where cutting could take place , but will require an adaptation to the ground support mechanisms required , Eklind confirmed . This has seen both Epiroc and Hecla work on a suitable rock bolting process to support the areas in and around the machine .
Greens Creek is also accessed via ramp , whereas access to the underground operation at Lucky Friday is through a shaft .
Eklind concluded : “ Hecla and Epiroc remain committed to the project , with certain adaptations to suit the new environment having been worked through over 2022 . We will continue with this process in 2023 .”
The Mobile Miner 22H Epiroc has manufactured , meanwhile , is still in South Africa , with preparations ongoing for a future test .
While Eklind was not able to say anymore on this project at the time IM went to press , he expected to be able to reveal more details in the March quarter .
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 .
Epiroc , Eklind says , remains focused on these two projects , yet the conversations with other mining companies around the concepts and applications for mechanical rock excavation continue to occur .
“ We do see a continuous interest from our customers in various applications in the mechanical rock excavation technology ,” he said . “ As mines go deeper , there are several challenging engineering issues for miners to address . I think using mechanical rock cutting means several of these can be addressed in a safer , much more productive way .
“ We , at Epiroc , are leaders in mining equipment and remain committed to this potential game changer for the mining industry . We will continue to apply this technology through collaboration with partners and , together with our digitalisation , electrification and automation technology solutions , will help transform the industry .”
Progressive excavation
In this same feature last year , IM reported on
progress with Robbins ’ novel TBM solution that uses disc cutter technology proven on traditional , circular machines to excavate rock with a reciprocating cutterhead and swinging cutterhead motion for the creation of a
Robbins has made significant progress with the MDM5000 ’ s first mine site application , having , by September 2021 , clocked up more than 1,700 m of advance at rates up to 52 m in one week and 191 m in one month at the Fresnillo silver mine in Mexico
Earlier this year , Komatsu Ltd , through its subsidiary , Komatsu Cummins Chile Ltda , agreed to trial a new tunnel excavation method using Komatsu ’ s newly developed Mining TBM at Codelco ’ s Chuquicamata Underground mine in Chile . The trial , to start in 2024 , is geared towards speeding up the potential introduction of this innovative technology .
Komatsu developed the first TBM for rock excavation in 1963 for use in civil engineering in Japan . Since that time , the company has introduced a cumulative total of more than 2,300 TBMs ( including its Micro Tunneling Machine ) to the market .
Based on Komatsu ’ s experience in excavation , the Mining TBM is equipped with new technologies that enable adaptability to small curves , reversing and passing intersections in hard-rock tunnel excavation . Use of TBMs has generally been limited to excavating near straight tunnels , but this new technology improves the flexibility of the equipment and enables excavation of tunnels in line with the designs of each mine , according to Komatsu .
The Mining TBM works by continuously performing a series of processes , such as excavating rock with disc cutters and discharging the chipped rock backwards with belt conveyors , while fortifying the excavated tunnel wall . Excavation with disc cutters improves tunnel strength and stability by creating a circular tunnel shape with smooth walls with less damage to the excavated tunnel ( compared with drill and blast ).
To support customer needs for increasingly sustainable ways of mining , the new machine runs off electricity , does not require the use of
Komatsu and Codelco have agreed to trial a new tunnel excavation method using Komatsu ’ s newly developed Mining TBM at the Chuquicamata Underground mine in Chile
blasting and performs a series of tunnel excavation processes with a single machine , reducing the number of vehicles required . The result is a new excavation option that reduces the creation of greenhouse gases and particulate matter emissions for an improved underground environment that requires less ventilation than other methods , it says . At the same time , it significantly increases the productivity of personnel associated with tunnel excavation work compared with conventional methods .
In response to climate change and the need for environmentally friendly solutions , Komatsu has been focusing on the development of equipment for the future of underground hard-rock mining under the
slogan of “ No Blasting ”, “ No Batch ”, “ No Diesel ”. The Mining TBM and the new method embody this forward-looking approach and seek to help
customers improve safety , environmental friendliness and productivity at underground mines , while also helping them achieve a revolution in their mining operations , it said .
16 International Mining | NOVEMBER / DECEMBER 2022