The name bell pit comes from the shape of the excavation, with a narrow vertical shaft sunk into the coal or iron ore seam, which was then opened out into a small chamber. Little timber was used, so once the roof became unsafe, the pit was abandoned and another shaft sunk nearby. Coal was cut by using picks and shovels. Man and coal were transported by a basket. Candles or lamps were used for illumination. As indicated in the photograph this is the earliest system of underground mining.