出典:Wiktionary
出典:Wikipedia
出典:『Wikipedia』 (2011/03/29 02:52 UTC 版)
A bell pit is a primitive method of mining coal, iron ore or other minerals where the coal or ore lies near the surface.. A shaft is sunk to reach the mineral which is excavated by miners transported to the surface by a winch and removed by means of a bucket, much like a well. It gets its name because the pit in cross section resembles a bell.