A glossary of mining and metallurgical terms

62 A GLOSSARY OF MIXING AND METALLURGICAL TERMS.
Oil-well. A dug or bored well, from which petroleum Is obtained
by pumping or by natural flow.
Old man. Ancient workings ; goaves.
Old men. The persons who worked a mine at any former period
of which no record remains.
Open cast, Scot, See Open cut.
Open-crib timbering. Shaft timbering with cribs alone, placed at
intervals.
Oj^en cut. A surface-working, open to daylight.
Open-front. The arrangement of a blast furnace with a jore-
hearth.
Open-hearth. See Reverberatory furnace.
Openings. The parts of coal mines between the pillars, or the
pillars and ribs.
Opens. Large caverns.
Open-sand castings. Castings made in moulds simply excavated
in sand, without Jiasks.
Open-work. A quarry or open cut.
Operator, Penn. The person, whether proprietor or lessee, actu-
ally operating a colliery.
Ore. 1. A natural mineral compound, of the elements of which
one at least is a metal. The term is applied more loosely to all
metalliferous rock, though it contain the metals in a free state, and
occasionally to the compounds of non-metallic substances, as sulphur
ore. 2. Corn. Copper-ore; tin-ore being spoken of in Cornwall
as tin.
Ore-hearth. See Scotch hearth.
Ore-washer. A machine for washing clay and earths out of
earthy brown-hematite ores.
Orjjinient. Sesquisulphide of arsenic.
Outbye or Outbycnde, Newc. Nearer to the shaft, and hence
further from the foreu-inning.
Outcrop. The portion of a vein or stratum emerging at the sur-
face, or appearing immediately under the soil and surface-debris.
Outlet. The passage by which the ventilating current goes out of
a mine. See Upcast.
Outpnd. The product of a mine.
Oval groove. A groove of U-section in a roll.
Overburden. 1, Corn. See Burden (1). 2. To charge in a
furnace too much ore and flux in proportion to the amount of fuel.
3. The waste which overlies the good stone iu a quarry.