Mining giant, Rio Tinto, has announced full scale trials will begin in 2012 in Australia for the first of three new tunnelling systems that could revolutionise the way mines are excavated today. This first system has been created in partnership with Aker Wirth, whilst Rio Tinto is also partnering Herrenknecht and Atlas Copco in the design of two other excavation systems that could see the tunnelling industry play an integral, and ever increasing part in the multi billion dollar mining industry.
The work is part of Rio Tinto’s Mine of the Future programme, which aims to enable Rio Tinto to more effectively carry out exploration; more efficiently exploit resources; and to allow safer, faster and deeper underground operations whilst economically recovering valuable mineral resources from increasingly difficult deposits.
Rio Tinto Head of Innovation John McGagh said the significant new investment offers the possibility for a step-change improvement over conventional drill and blast practices.
“Depending on rock conditions, this system should provide a capability to excavate at more than double the rate of conventional methods,” Mr McGagh said.
“For example, in a typical deep copper ore body, the rate of horizontal tunnelling could be as high as 10–13m a day, using this new system.”
This new tunnel boring system trial has been integrated into a previously announced US$90M pre-feasibility expansion study at Northparkes in August 2010 by Northparkes’ JV partners Rio Tinto and the Sumitomo Group companies.
Mr McGagh said the trial will complete the final stage of performance verification of the new system.
“This system incorporates continuous mechanical rock excavation that will not damage new tunnel walls, while still providing the ability to mechanically install ground support in parallel with tunnel advance,” he explained.
The new tunnel boring system is expected to arrive in Australia in early 2012. The system is 64m long, and has a maximum boring diameter of 6m. After the trial this technology is destined for use in other Rio Tinto underground mining operations internationally.
The new Aker Wirth equipment is based on the company’s extensive experience in underground hard rock mining and tunnelling. Its machinery will combine the flexibility of a roadheader operation with the robustness of a TBM and leans heavily on the experiences of a previous version from the early 1990s.
Atlas Copco’s new tunnelling machine, the Modular Mining Machine, is based on learnings from its previous Robbins Mobile Miner combined with many years of experience in a wide range of novel rock excavation techniques.
Herrenknecht’s new Shaft Boring Machine combines synchronous mechanical hard rock excavation, muck transport and rock support in a single system. The innovative single-system concept offers significant improvements in shaft construction rates and safety while minimizing technical risks.
All three new concepts are a result of civil tunnelling industry technologies combined with input from Rio Tinto mining experts and contractor partners Redpath and Cementation.