Revolution in underground mining

Together with Rio Tinto, one of the world’s largest mining companies, Aker Wirth developed a new, innovative tunnel boring system for underground tunneling and mining  the Mobile Tunnel Miner (MTM). The machine concept combines the flexibility of a roadheader with the robustness of a tunnel boring machine. The knowledge gained from a previous version developed and tested already by Aker Wirth is also exploited.

 

The self-propelled machine moves on a crawler and a walking mechanism and excavates rock with six powerful 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.

 

This new tunneling system is part of Rio Tinto’s Mine of the Future™ programme and will be tested in a full-scale trial at the Rio Tinto Northparkes copper mine in Australia this year.

 

Performance

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 tunneling rate of 10 m per day.

 

Energy efficiency

With undercutting technology, the MTM 6 is especially efficient with tunneling in hard rock (up to max. 300 MPa). The considerably lower tensile strength of the rock when compared to compressive strength is exploited in this respect. The roller cutters are positioned at a slight angle to the cutter arms, thus undercutting the rock and removing pieces about the size of the palm of a hand. The energy required for undercutting is about half that used for conventional disc cutters on traditional tunnel boring machines.

 

Flexibility & mobility

The Mobile Tunnel Miner 6 is able to cut rectangular or horseshoe-shaped cross-sections in addition to circular tunnels with a bore diameter of up to 6 m. 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 m, 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 m long machine is only 30 m. This means it can master considerably tighter curves than a classic tunnel boring machine which has a turning radius of approximately 500 m under comparable conditions of use. 

 

Safety

In contrast to drill and blast, which up until now has been the usual method employed in rock of this strength, tunneling 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 minimises 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 revolutionise safety and efficiency in underground mining with the new Mobile Tunnel Miner”, says Einar Brønlund, CEO at Aker Wirth with absolute conviction. “This innovative technology will improve health, safety and environmental protection significantly and makes working conditions more attractive.”

 

Simone Grönemeyer

Manager Communications

P +49 2431 83-459 

F +49 2431 83-83 459 ½ 
Email: simone.groenemeyer@akersolutions.com