There were one or two transverse splits, which indicated a heavy mass of rock was ready to come down.

None of the men were near the spot, and he knew they were occupied, but Driscoll had left a few props between the timbers, ready for use where the roof was weak.

Thirlwell found one and dragged it to the spot.
"We'll put this up and then I think I'll get a fresh beam across." Scott helped him to raise the timber.

It was a few inches too long, and crossed the space between floor and roof with a small slant, but it was meant to do so, in order that when its lower end was driven forward until it stood upright it would wedge fast the beam above.

Then Thirlwell brought an ax and struck the prop some heavy blows with its back while Scott steadied the top.