Rio Tinto’s Northparkes copper mine in central west New South Wales, Australia, will provide the backdrop for a full-scale trial of an innovative tunnel boring system for underground mining developed by Aker Wirth with support from the global mining giant.
The Mobile Tunnel Miner (MTM) combines the flexibility of a roadheader with the robustness of a tunnel boring machine. Test results of a previous version developed by Aker Wirth were used to help bring about the final design of the newly-launched MTM.
The self-propelled machine moves on a crawler and a walking mechanism and excavates rock with six hydraulically actuated arms fitted with disc cutters. The muck is conveyed to the rear of the machine by a loading apron with loading disks and via a chain conveyor where it is loaded.
The MTM 6 sets new standards in mining development. In comparison to drill and blast, the MTM 6 is designed to more than double current performance with a potential daily tunnelling rate of 10 metres, and is especially efficient tunnelling in hard rock.
The MTM 6 is able to cut rectangular or horseshoe-shaped cross-sections in addition to circular tunnels with a bore diameter of up to 6 metres. This permits the direct boring of the desired tunnel shape, whereas the lower part of a round cross section usually needs to be backfilled where a conventional tunnel boring machine is used. With a flexible bore diameter of up to 6 metres, the self-propelled Mobile Tunnel Miner can be used for a variety of applications.
“The machine is also an innovation in terms of its mobility: it can move flexibly forward using a walking mechanism and backward with a crawler. Thanks to several swivel joints, the turning radius of the 75 metre-long machine is only 30 metres. This means it can master considerably tighter curves than a classic tunnel boring machine which has a turning radius of approximately 500 metres under comparable conditions of use,” says Aker Wirth chief executive officer Einar Brønlund.
He says the machine offers a significant increase in safety for mine staff because tunnelling with the MTM requires considerably less work from personnel at the tunnel face. The machine is operated from a central control cabin located on the machine itself.
“The high degree of automation minimizes contact between personnel and both moving components and rock. Thanks to its flexibility, the MTM can be easily driven away from the tunnel face for maintenance purposes, which also contributes to the safety of operating personnel.
“We will revolutionize safety and efficiency in underground mining with the new Mobile Tunnel Miner. This innovative technology will improve health, safety and environmental protection significantly and makes working conditions more attractive,” says Einar Brønlund.
The testing of the MTM at Northparkes later this year is part of Rio Tinto’s ‘Mine of the Future’ program.