a. To bear in; underholing or undermining; driving in at the top or at the
side of a working.
b. Eng. A calcareous or clay ironstone nodule, Derbyshire. Arkell
c. The mass of iron, which, as a result of wear of the refractory
brickwork or blocks in the hearth bottom of a blast furnace, slowly
replaces much of the refractory material in this location.
Dictionary of Mining, Mineral, and Related Terms