Bob cowered in a corner of the shaft, holding his shirt over his mouth and squeezing his eyes shut against the shower of rock and dust that enveloped him.  For several minutes he stayed where he was, hoping against hope that the quake was over.  Slowly the shaking stopped and the sifting sound of sliding sand ground to a stop.  Still he stayed where he was, afraid to move – afraid to breathe.

Sixty-two men had filed down into the Banner Mine shaft that gray October morning.  Sixteen of them had followed Bob when he split off into an abandoned shaft, some eighty feet beneath the surface and well south of the main work force.  The boss wanted this mapped.  They were there to get it done.  None of them had thought, that morning in the pre-dawn haze, that they might not make it back out.  This was mining, and the hazards were known to all.  You didn’t think about it if you wanted to keep your sanity.  You got your orders and you kept your eyes on the work at hand.  That’s how you made it home at night.

The shaft they were mapping had been out of use for at least thirty years.  Nobody even remembered it.  Company records showed the ore they were mining had dried up and the work shifted elsewhere.  But Bob had wondered when they reached the shaft opening.  Why, if it was simply a dry vein, had the barricade been built?  That was not normal procedure.  Barricades were only built on a potential hazard.  No record of a hazard could be found, though, potential or otherwise.  For the better part of an hour they tore at the offending planks before Gus had pulled Bob aside.  “Hey Bob, there’s something real strange here,” he said, and his eyes were big in the lamplight.
“Yeah?  What’s that?” asked Bob.
“Did you pull any nails out of that wood?”
“Nah, they’re all rusted.  Couldn’t find the heads.”
“Yeah, well I found some after we broke through.  Look here,” said Gus, and showed him the wood in question.
“Okay, so what?  What’s eating you, Gus?”
“They’re spikes, Bob.  Six inch spikes, and they’re driven from inside the shaft.  Who uses six inch spikes to nail two-by-sixes together?  And who nailed them from the inside?  The maps don’t show any outlet except the one we came through to get here.” Gus was talking low so the rest wouldn’t overhear, but Bob could see some of the boys were casting questioning looks their way.  He wasn’t really following Gus’s train of thought, but figured they better sit down and think it through.  Gus was a veteran; if he saw a problem, he needed to be heard.