What does "spall" mean?

Spall: (Mining) To break into small pieces, as ore, for the purpose of separating from rock. Pryce.

Additional senses

  1. 2.(Masonry) To reduce, as irregular blocks of stone, to an approximately level surface by hammering.
  2. 3.To give off spalls, or wedge-shaped chips; -- said of stone, as when badly set, with the weight thrown too much on the outer surface.

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