second mining

second mining

[′sek·ənd ′mīn·iŋ]
(mining engineering)
In underground coal mining, a procedure in which the pillars left for roof support are removed as mining operations move back out of the previously mined area.
References in periodicals archive ?
This is Vulcan's second mining operation in the Azusa area.
The company has started its second mining campaign at LGP.
Investors from Lecanto, Florida are expected to operate the second mining company that will invest US$15 million to produce bauxite.
The new entity, BHP Billiton, which will be quoted on the London and Australian stock exchanges, will be worth some USD28 billion, making it the world's second mining industry behind the American Alcoa group.