pcray1231
Well-known member
Well, a sheet metal pipe, like the one that was on one end, might protect you from the occasional small rock dropping from the ceiling. But any larger rocks are just gonna crush it. And it wouldn't have the strength to add any sort of structural support to prevent total cave in, if that's a concern.
They don't make thick diameter, seamless pipe that large, to my knowledge. These are made by piercing, the metal gets hot and a spinning mandrel essentially drills out the middle. I don't know of any equipment in the world capable of handling something bigger than 4 or 5 ft in diameter. And if it does exist, it'd be very expensive.
I don't know enough about the specifics of the tunnel, rock types, how stable it is, etc. But I would guess the path would be more likely to be placing large rock bolts in the ceiling and maybe walls. Then perhaps some sort of structure, or a sheet metal pipe, to protect from the smaller stuff.
They don't make thick diameter, seamless pipe that large, to my knowledge. These are made by piercing, the metal gets hot and a spinning mandrel essentially drills out the middle. I don't know of any equipment in the world capable of handling something bigger than 4 or 5 ft in diameter. And if it does exist, it'd be very expensive.
I don't know enough about the specifics of the tunnel, rock types, how stable it is, etc. But I would guess the path would be more likely to be placing large rock bolts in the ceiling and maybe walls. Then perhaps some sort of structure, or a sheet metal pipe, to protect from the smaller stuff.