A glossary of mining and metallurgical terms

84 A GLOSSARY OF MIXING AND METALLURGICAL TERMS.
Stempel or Stemple. 1. Derb. One of the cross-bars of wood
placed in a mine-shaft to serve* as steps. 2. A stuU-piece. 3. A cap,
both sides of which are hitched instead of being supported upon legs.
See Stull.
Stenton, Nbwc. A passage between two winning headways. A
stenton-wall is the pillar of coal between them.
Step-grate. A grate made in steps or stairs, to promote complete-
ness of the combustion of the coal burned upon it.
Step-vein. A vein alternately cutting through the strata of
country-rock, and running parallel with them.
Stetefeldt furnace. A shaft-furnace for desulphurizing or chlori-
dizing-roasting, in which the pulverized charge falls freely down the
shaft.
Stirrup. See Temper-screw.
Stockwork (Germ., Stockwerk). An ore-deposit of such a form
that it is worked in floors or stories. It may be a solid mass of ore,
or a rock-mass so interpenetrated by small veins of ore that the
whole must be mined together. Stockwoi'ks are distinguished from
tabular or s^ee^-deposits (veins, beds), which have a small thickness
in comparison with their extension in the main plane of the deposit
(that is, in strike and dip).
Stone-coal. See Coal.
Stone-head, Eng. The solid rock first encountered in sinking a
shaft.
Stoop-and-Rooms, Scot. See Post-and-Stall.
Slope, Corn. To excavate ore in a vein by driving horizontally
upon it a series of workings, one immediately over the other, or vice
versa. Each horizontal working is called a stope (probably a corrup-
tion of step), because when a number of them are in progress, each
workins: face beino- a little in advance of the next above or below, the
whole face under attack assumes the shape of a flight of stairs. When
the first stope is begun at a lower corner of the body of ore to be re-
moved, and, after it has advanced a convenient distance, the next is
commenced above it, and so on, the process is called orey-Aa/K?stoping.
When the first stope begins at an upper corner, and the succeeding
ones are below it, it is under-Jiand stoping. The terra sloping is
loosely applied to any subterranean extraction of ore except that
which is incidentally performed in sinking shafts, driving levels, etc.,
for the purpose of opening the mine.
Slopping. 1. See Sloping. 2. A partition of boards, masonry,