The supporting of undercut coal with short wedges or chocks. CTD
An English term for chocks, or blocks spiked into the corner of a shaft to
form a bearing for the side-walling piece, or the blocks used in headings
to separate the cap and poling board. See also:collaring
Stauffer
a. In crushing practice, a stoppage of the downward flow in a
rock-crushing chamber. See also:choke point
b. A point in a cave or at the base of a pitch blocked by the influx of
clay, sand, gravel, or similar material. AGI
A recrushing of fine ore due to the fact that the broken material cannot
exit a machine before it is again crushed. CF:free crushing
a. A mine atmosphere that causes choking or suffocation due to
insufficient oxygen. As applied to "air" that causes choking, does not
mean any single gas or combination of gases. Fay
b. A name sometimes given in England to carbon dioxide.
See also:blackdamp; damp. Fay
In comminution, rolls are choke fed when fed all of the material that they
will take. The product of choke-fed rolls is never so uniform as when free
feeding is used. Choke feeding is used only on feed of diameter about 1/4
in (0.6 cm) or less. CF:free fed
A feeding arrangement in which the potential rate of supplying material at
the feed point exceeds the rate at which the conveyor will remove
material.
As deliberately used in roll crushing of ore, feed at a rate greater than
can be discharged at the set of the machine, so that the rolls are sprung
apart, the angle of nip is increased, and the product contains oversize.
Pryor, 3
Bottleneck of any crusher. Pryor, 3
A chain or cable so fastened that it tightens on its load as it is pulled.
Nichols, 2
Stoppage of flow, due to obstructed discharge, sticky material, packed and
compacted fines, or bad control. Pryor, 3
A monoclinic mineral, (Mg,Fe)5 (SiO4 )2 (F,OH) (sub
2) ; humite group; commonly occurs in contact-metamorphosed dolomites.
Also spelled condrodite.
An intrusive mass that is so irregular in form and its relationship to the
invaded formations is so obscure that it cannot be designated a dike,
sill, or laccolith.
a. To break up and drill through boulders, other rock, or lost core
encountered in sinking a drivepipe or casing through overburden. It is
done by impact produced by lifting and dropping a chopping-bit-tipped
string of drill rods.
b. Som. A local term for fault.
To break up boulders and other rock material below the bottom of casing or
drivepipe by using a chopping bit attached to drill rods.
See also:chop
A feeder in which a power-operated, swinging quadrant gate delivers
material at a predetermined rate. The action is similar to a reciprocating
plate feeder.
A term used to describe the digging action of a dragline when excavation
takes place with the bucket heel above the line of the cutting lip. This
term is usually used when referring to an operating method in which the
dragline bucket excavates above the line of the fairlead and fills above
tub level. Austin
A steel, chisel-shaped cutting-edged bit designed to be coupled to a
string of drill rods and used to fragment, by impact, boulders, hardpan,
and lost core in a borehole. Also called chisel bit; chisel-edge bit;
chisel-point bit; long-shank chopping bit. CF:cross-chopping bit
Long
The effect produced by the chain joint centers being forced to follow arcs
instead of chords of a sprocket pitch circle. Jackson, 1
The length of one side of the polygon formed by the lines between the
joint centers as a chain is wrapped on a sprocket. It is a chord of the
sprocket pitch circle and is equal to the chain pitch. Jackson, 1
A general term for a group of mixed rocks, which are the result of the
injection of the crystallization products of intruding magmas into, and/or
the mixture of such material with, the enclosing rocks, sedimentary or
metamorphic. There are several varieties. The term is not widely used.
CF:migmatite