a. A piece of timber used as a temporary support for a mine roof.
Zern
b. Length of timber used as a roof support in longwall mining. Modern
variants include expandable steel props which can be hydraulically or
mechanically lengthened; used in stratified deposits. Pryor, 3
An openpit quarry sunk below ground level. Access is gained by stairs,
ladders, or mechanical hoists, and material is conveyed from the quarry by
inclined tracks, trucks, derricks, or cableway hoists. These pits may
reach depths of several hundred feet. A drainage scheme will in most cases
be necessary, as the pit will form a natural sump for both surface and
subsoil water. This type of quarry is often used for gravel or soft rock
that can be extracted by some form of digging.
See also:hillside quarry
a. The number of working places, or the length of a longwall face,
available in a mine for coal production. Nelson
b. The extent of the opening in a mine; pit space. Fay
Eng. Winding rope; a hoisting rope. Fay
a. Use of small untimbered pits to gain access to shallow alluvial
deposits or ore dumps for purpose of testing or valuation.
Pryor, 3
b. Sampling shallow deposits by means of trial pits, usually about 2 to 3
ft (0.6 to 0.9 m) in diameter. In reasonably dry ground, depths of 50 ft
(15.2 m) or more may be reached. Pit sampling is often used to assist site
investigations as it provides the maximum of information regarding the
nature of deposits and bedrock. See also:trial pit
a. Sand usually composed of grains that are relatively angular; it often
contains clay and organic matter. When washed and screened it is a good
sand for general purposes. Zern
b. Sand from a pit, as distinct from river or sea sand. Arkell
The name given to the shale from a drift opened in the side of the ravine
at a level 62 ft (18.9 m) below that of the Pittsburgh coal seam.
Rice, 2
The angle at which the wall of an open pit or cut stands as measured along
an imaginary plane extended along the crests of the berms or from the
slope crest to its toe.
An old name give to viscid bitumen. Syn:maltha
See also:mineral tar
The mineral amorphous, hydrous, ferric arsenate sulfate. It is brown to
yellow and red; earthy; occurs as crusts and botryoidal layers; a common
oxidation product of arsenical ores. Also spelled pittizite.
Syn:pitchy iron ore
a. The act of digging or sinking a pit. Fay
b. Testing an alluvial deposit by the systematic sinking of small shafts,
the material recovered being subsequently tested. The practice is confined
to shallow depths; i.e., down to about 50 ft (15.2 m) in fairly dry soft
ground. Nelson
The Pittsburgh coal which outcrops prominently in the vicinity of
Pittsburgh and extends under a large area of western Pennsylvania,
northern West Virginia, northwestern Maryland, and eastern Ohio. It
belongs in the Carboniferous system, Pennsylvanian series, at the base of
the Monongahela formation. Rice, 2
Water from the underground workings of a mine. BS, 5
The various kinds of timber used at a mine, mainly as supports.
Nelson
Cornish pumps and other engineering appliances in and near a mine shaft.
Pryor, 3
A nonrotating axle or hinge pin. Nichols, 1
The highest type of combined elevator and conveyor. It consists of two
long-pitch roller chains joined by crossbars on which are hung the buckets
in such a way that they can be completely turned over.
Pit and Quarry
A type of conveyor using pivoted buckets attached between two endless
chains that operate in suitable guides or casing in horizontal, vertical,
inclined or a combination of these paths over drive-corner and takeup
terminals. The buckets remain in the carrying position until they are
tipped or inverted to discharge. Syn:bucket elevator
A tractor dead axle, or any fixed shaft that acts as a hinge pin.
Nichols, 1
A hollow hinge pin. Nichols, 1
a. See:in situ
b. The part of a mine in which a miner works by contract is known as his
"place" or "working place."
c. A point at which the cutting of coal is being carried on.