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punch prop

A short timber prop for supporting coal in holing or undercutting; a
sprag. Standard, 2

puppet valve

A valve that, in opening, is lifted bodily from its seat by its spindle
instead of being hinged at one side. See also:poppet; poppet valve.
Fay

puppy

An underground set of pumps. Fay

pure bending

In mine subsidence, bending without fracture. Briggs

pure coal

See:vitrain

pure culture

A collection of microbial cells of the same species in a container that is
devoid of any other form of life. Rogoff

pure oxide

Any of a group of refractories including alumina, magnesia, thoria,
zirconia, beryllia, and ceria. Osborne

pure oxide ceramic

Ceramic product made from any of the pure oxides of nonmetallic materials;
i.e., Al2 O3 , MgO, SiO2 , etc.

pure shear

A strain in which a rock body is elongated in one direction and shortened
at right angles to this in such an amount that the volume remains
unchanged. AGI

pure steel

The product of a basic open-hearth furnace refined to a point where the
impurities are reduced to the lowest practicable minimum, after which
copper and molybdenum are added in correct proportions.
Mersereau, 2

purlins

Timbers spanning from truss to truss, and supporting the rafters of a
roof. Crispin

puron

High-purity iron. Osborne

purple blende

An old syn. for kermesite. Fay

purple copper ore

A miners' term for bornite. Syn:bornite

purple ore

Sintered pyritic ore.

purpurite

An orthorhombic mineral, MnPO4 ; forms a series with heterosite;
deep red or reddish purple; forms small, irregular masses as an alteration
product of lithiophilite and triphylite; at Pala, CA; Hill City, SD;
Newry, ME; and the Erongo Mountains, Namibia.

pushbutton coal mining

A fully automatic and remotely controlled system of coal cutting, loading,
and face conveying, including self-advancing roof support systems.
See also:manless coal face

pushbutton winding control

A system in which the operation of the winder is similar to automatic
cyclic winding, but the starting is instigated by the onsetter and
banksman. When everything is ready for winding, the onsetter and banksman
press their respective start pushbuttons and the winder starts,
accelerates, and banks automatically without the intervention of the
winding engineman. With this form of control, loading and discharging of
the skips is fully automatic. See also:automatic cyclic winding;
manual winding control. Nelson

pusher

a. A laborer who pushes loaded mine cars on tracks from underground
working places to haulage roads where they are hooked up to a locomotive
and hauled to the surface, shaft, or slope bottom for hoisting. A pusher
may, at bituminous mines, shift empty and loaded cars in and about the
tipple, where coal is prepared for market. Also called: car puller; car
shifter; headsman; putter; trailer; trammer. Syn:mule; wheeler.
DOT
b. One who encourages or hastens the miners. Also called jigger boss.
Ricketts
c. A tractor that pushes a scraper to help it pick up a load.
Nichols, 1

pusher tractor

A bulldozer exerting pressure on the rear of a scraper loader while the
loader is digging and loading unconsolidated ground being excavated and
moved during opencast mining.

push hole

A hole through which glass is introduced to a flattening furnace.
Standard, 2