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olivinophyre

Porphyry containing olivine phenocrysts. Fay

ollenite

A type of hornblende schist characterized by abundant epidote, sphene, and
rutile. Garnet is one of the accessories. AGI

O.L.P. steel process

A steelmaking method similar to the L.D. except that powdered lime is
blown with the oxygen stream (therefore, the letters O.L.P.--oxygen-
lime-powder). See also:L
Nelson

ombrogenous peat

Peat, the nature of which is determined by the amount of rainfall.
Tomkeieff

omnibus

In glassmaking, a sheet-iron cover to protect, from drafts, the glass
articles in a leer. Standard, 2

omnidirectional hydrophone

A hydrophone whose response is essentially independent of angle of arrival
of the incident sound wave. Hy

omphacite

A mineral of the pyroxene group intermediate among aegirine, jadeite, and
augite; i.e., high in aluminum and sodium, and of high-pressure origin;
monoclinic; pale to grass green; occurs in eclogites.

o.m.s.

a. Output (usually in hundredweights) per manshift. It is a method of
expressing the productivity of mines, miners, and management.
Nelson
b. N. of England. Output (usually tons) per manshift. Interpretation
depends on the basis for calculating manshifts, e.g., face o.m.s. is based
on manshifts at the face; seam o.m.s. on piecework and bargain work
manshifts in the seam; overall (pit) o.m.s. on all manshifts underground,
including datal labor. Trist

on air

a. The state of a pump which is operating although having no liquid in its
working parts. BS, 10
b. Scot. Said of a pump when air is drawn at each stroke.

oncosimeter

An instrument for determining the specific gravity of a molten metal by
the immersion of a ball made of another metal and of known weight.
Standard, 2

onegite

A variety of goethite. Hey, 1

one on two

A slope in which the elevation rises 1 ft (m) in 2 horizontal ft (m).
Nichols, 1

one-part line

A single strand of rope or cable. Nichols, 1

one-piece set

A term applied to a single stick of timber, called a post, stull, or prop.
Post and prop are applied to vertical timbers, and stull is applied to
inclined timbers, or those placed horizontally. See also:set
Lewis

one shot

a. A borehole-survey instrument that records a single inclination and/or
bearing reading on each round trip into a borehole. Long
b. Single shot.

one-shot exploder

See:Little Demon exploder

one-spot strip mining

Consists of three operations: the top material is cast out of the way; pay
material is dug and trucked away; and the top is pushed or cast back in.
Nichols, 1

one-way ram

A hydraulic cylinder in which fluid is supplied to one end so that the
piston can be moved only one way by power. Syn:single-acting ram
Nichols, 1

one-way ventilation

See:peripheral ventilation

onion-skin weathering

See:spheroidal weathering

onlap

a. An overlap characterized by the regular and progressive pinching out,
toward the margins or shores of a depositional basin, of the sedimentary
units within a conformable sequence of rocks, in which the boundary of
each unit is transgressed by the next overlying unit and each unit in turn
terminates farther from the point of reference. Also, the successive
extension in the lateral extent of strata (as seen in an upward sequence)
due to their being deposited in an advancing sea or on the margin of a
subsiding landmass. Ant: offlap. Syn:transgressive overlap
CF:overlap
b. The progressive submergence of land by an advancing sea.
CF:transgression