ABSTRACT
Environmental issues today receive increasing attention the world over. Apart from providing their citizens with fresh water, many cities and municipalities adopt schemes to collect and treat waste water and sewage. Where possible, the collector system is put underground in the form of—preferable bored—tunnels. The often great length of the collectors and the urgency of constructing them as fast and as cost-effectively as possible inevitably leads to the requirement of high speed tunnelling. Modern Tunnel Boring Machines (TBM) themselves are capable of high rates of advance in all but the most disturbed, unstable rock conditions. But the machines are only one part of a total tunnelling system in which the logistical provisions more often than not determine the overall tunnelling speed.
In the Blue Mountains Sewerage Scheme near Sydney, Australia, a continuous belt conveyor system was used to provide a high capacity muck transport facility in long, relatively small diameter, single entry tunnels. Though it allowed the TBM to set a new world record, the author believes that further development of the conveyor system will strengthen the trend towards really high speed tunnelling,
