After all the samples, investigations, and reports are in, it's time for contractors to decide the best way to go about building the tunnel. This includes what equipment they want to employ.
There are two basic ways to dig a hole.
a) A Tunnel Boring Machine (TBM): these technological giants cut the tunnel hole and support it in one go. Think of a hand drill, drilling a hole into wood. This is most likely to be the method used for the Toowoomba tunnel.
b) A roadheader: roadheaders are machines that resemble classic excavator, but with a rotating cutter instead of a bucket. They cut away the tunnel progressively and require more machines and more people than a TBM.
Complete the interactive quiz below. It challenges you to connect the facts and research you’ve picked up so far with practical situations in which they would apply. Let's go!