"The main shaft?"

"Yes."

"I heard the crash. I shouted to you but I didn't hear any answer. Are you hurt?"

"No. I'm all right. I jumped back just in time."

"Where are you now? Can't you reach me?"

"The tunnel caved in, too. I'm trying to dig my way through to you."

There was a moment of silence. Clearly, the news came as a surprise to Frank.

"That's bad," he said, at last. "Do you think you can get through?"

"I think so. I have the crowbar with me." Joe attacked another rock on the heap, edging the end of the crowbar into a crevice.

"How bad is the cave-in?"