—v.fôr-pōl', fōr-), [key]
—n., v., -poled, -pol•ing. Mining.
Also called spile, spill. any of a number of boards or timbers driven forward on top of a set to protect miners lengthening a tunnel from falling debris.
to reinforce (the end of an excavated tunnel) with forepoles.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.