In room and pillar mining, seams of coal are mined partially, leaving large pillars of coal intact to support the overlying layers of rock. Mining by this method creates a network of alternating open spaces and large pillars of coal (Fig. 19.4(a)).

What is the room and pillar mining method?

Room and pillar (variant of breast stoping), is a mining system in which the mined material is extracted across a horizontal plane, creating horizontal arrays of rooms and pillars. To do this, "rooms" of ore are dug out while "pillars" of untouched material are left to support the roof overburden.

Why is room and pillar mining bad?

In room-and-pillar mines, columns of coal are left to support the ground above during the initial mining process, then they are often taken out and the mine is left to collapse, which is known as subsidence. ... It is these effects of mining that nobody sees but are the most troubling of all.