Tunnel boring machine

Development will include the use of a tunnel boring machine to excavate a four-kilometer decline.

Did a bit of research into this this morning.

Use of TBM potentially cuts a year off the development time there compared with traditional drilling and blasting of the decline, and it will produce a, a sealed, fully supportable, fully supported decline which will protect against ingress of water, which is, um, a factor here.

David, Robert Friedland obviously a permabull on copper, so no surprise to see an aggressive development timeline to be able to deliver copper cathode into, into the US sooner rather than later, and harnessing technology to do so.

What, what do you make of this, uh, feasibility?

How do you explain time and cost estimates on a giant national project like Snowy 2 being so wildly inaccurate? You're about to hear what went wrong and what could still go wrong.

Much of the risk is around TBMs, Tunnel Boring Machines, giant cylinders with names like Eileen or Monica.

When they go well, that warrants a party.

When they get stuck, that's costly.

Tunnels are rather tall spaces, like especially if you design train tunnels, inevitably you're gonna have a very, very tall space.

If you're dealing with, uh, TBM-borne tunnels, uh, you probably are dealing with quite tall spaces as well.

So in those circumstances, uh, having a back-layering formulated just means that some of the energy of the fire, some of the smoke generated by the fire, is moving upstream, upwards for a specific distance.

This distance could be quite short, 20, 30 meters.

Right.

And it's got overburden on the top because the TBM launchers were very shallow to the ground.

Yeah.

So we have to keep the TBMs down, pointing downwards, 4% grade, until we've reached its ultimate sort of like 25 to 28, 30 metre deep.

It's one of the deepest parts of the railway.

That's just up the Green Parkway shaft at Canterbury Works.

It's carrying a hill on top of it.

Right.