Spall

• POS: Noun, Verb (usu participle)

CIDE DICTIONARY

Spall, n. [OF. espaule; cf. It. spalla. See Epaule.].

 The shoulder.  Spenser.  [1913 Webster]

Spall, n. [Prov. E. spall, spell. See Spale, Spell a splinter.].

 A chip or fragment, especially a chip of stone as struck off the block by the hammer, having at least one feather-edge.  [1913 Webster]

Spall, v. t. 

•  To break into small pieces, as ore, for the purpose of separating from rock.  Pryce.  [1913 Webster]
•  To reduce, as irregular blocks of stone, to an approximately level surface by hammering.  [1913 Webster]

Spall, v. i. 

 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.  [1913 Webster]

OXFORD DICTIONARY

Spall, n. & v.
--n. a splinter or chip, esp. of rock.
--v.intr. & tr. break up or cause (ore) to break up in preparation for sorting.

Etymology

ME (also spale): orig. unkn.