A glossary of mining and metallurgical terms

78 A GLOSSARY OF MIXING AND METALLURGICAL TERMS.
Sinking-fire.
A forge in which wrought-iron scrap or refined pig-
iron is partially melted or welded together by mean?; of a charcoal-
fire and a blast.
Siphon-tap. See Arendf^' tap.
Sit or Sits. A settling or falling of the top of workings. See
Thrust and Creep.
Sizing. Separating ores according to size of particles, preparatory
to dressing.
Sleep or Ship, Corn. An iron box working between guides, in
which ore or rock is hoisted. It is distinguished from a kibble,'
which hangs free in the shaft.
Skew-plate. See Bloomary.
Skimmings or Skimpings, Corn. The poorest part skimmed off
the jigger.
Skull. A crust of solidified steel lining a Bessemer ladle.
Slack. Small coal ; coal dirt. See Culm (2).
Slag. The vitreous mass separated from the fused metals in
smelting ores.
Slag-hearth. A hearth on the principle of the Scotch-hearth for
the treatment of slags, etc., produced by lead-smelting in the rever-
beratory furnace. The English slag-hearth has one tuyere ; the
Castilian or Spanish, three.
Slag-lead. Lead obtained by a re-smelting of gray slag.
Slag-wool. A finely fibrous mass produced by blowing .steam or
air into molten slag.
Slant. A heading driven diagonally between the dip and the
strike of a coal-seam ; also called a run. See Run and Counter.
Slate. A sedimentary rock splitting into thin plates. The terms
.slate, shale, and schist are not sharply distinguished in common use,
particularly among older writers. Strictly, according to recent
authors, slate may be crystalline; schist is always so ; shale is always
(and slate most frequently) non-crystalline. There is also a notion
of coarser or less complete lamination attached to the term shale, as
of a rock splitting into thicker or less perfect plates than slale. Both
may be argillaceous, arenaceous, calcareous, silicious, etc., according
to their lithological character. The terms shtty, shaly, and .schistose
describe the respective structures.
Sleek, Newc. ]\Iud deposited by water in a mine.
Sleeper. See Sill.
Sleeping-table, Corn. A stationary huddle. For the strict dis-
tinction, sometimes made between huddle and table, see Buddie.