A borehole plugged by debris lodged at some point above the bottom of a
hole. The hole may be bridged deliberately by introducing foreign material
into the hole or accidentally by rock fragments sloughing off the
sidewalls of the borehole. Long
Collapse of a well bore around the drill stem. Williams
Deliberate plugging of a borehole at a point some distance above the
bottom by introduction of some type of foreign material or a plug.
See also:bridge
Consists of two steel bridge trusses braced together so as to form between
them a runway on which a bucket-carrying trolley runs.
Pit and Quarry
A low separating wall, usually made of firebrick, in a furnace.
Webster 3rd
A resistance wire connecting the ends of the leg wire inside an electric
detonator and which is embedded in the ignition charge of the detonator.
a. In crushing practice, the obstruction of the receiving opening by two
or more pieces wedged together, each of which could easily pass through.
Nelson
b. Formation of arches of keyed or jammed particles across the direction
of flow (of rock through apertures or of small particles through filter
pores). Pryor, 3
c. Arching of the charge across the shaft in a blast furnace or cupola.
d. Premature solidification of metal across a mold section before the
metal below or beyond solidifies. ASM, 1
e. Solidification of slag within the cupola at or just above the tuyeres.
ASM, 1
f. Welding or mechanical locking of the charge in a downfeed melting or
smelting furnace. ASM, 1
g. Closing of a section of a drill hole by loose blocks of rock or by
squeezing of plastic shale, etc.
A mechanical device that automatically selects two samples as the ore
passes through.
See:bridle rod
An anchor cable that is at right angles to the line of pull.
Nichols, 1
a. One of the chains used for supporting a cage from the winding rope.
Nelson
b. One of the safety chains used to support the cage if the shackle should
break or to protect a train of cars on a slope should the shackle or
drawbar fail. Fay
A connection between a bridle cable and a cable or sheave block.
Nichols, 1
A steel tie bar used to join the ends of two point rails to hold them to
gage in the proper position. Syn:bridle bar
N. of Eng. A beam or girder fixed across a shaft top.
An instrument used in measuring borehole deviation which transmits
electrical signals, communicating to the surface the position of a plumb
bob fitted with a needle relative to four electrodes arranged N.,S.,E.,
and W.--the needle and electrodes being immersed in the electrolyte.
Signals are matched with a similar arrangement of needle and electrodes at
the surface, and the needle then indicates the deviation and the direction
of deviation. Sinclair, 2
This consists of a head harness, mouthpiece, and noseclip, corrugated
breathing tube, Briggs equalizing device, 120 ft (36.58 m) of reinforced
air tubes, and a strainer and spike. It has neither bellows nor rotary
blower but depends entirely on the action of the equalizer for comfortabIe
respiration. The resistance to breathing is so low that reasonably hard
work can be done by the wearer over a period of 2 h or more. The air
supply tube is attached to the waist by a strong leather body belt.
Mason
A field term to denote the degree of luster of attrital coal compared with
the brilliant luster of associated vitrain. CF:dull attritus
AGI
See:bride cake
a. A type of banded coal defined microscopically as consisting of more
than 5% of anthraxylon and less than 20% of opaque matter; banded coal in
which translucent matter predominates. Bright coal corresponds to the
microlithotypes vitrite and clarite and in part to duroclarite and
vitrinerite. CF:dull coal
b. The constituent of banded coal that is of a jet black, pitchy
appearance, more compact than dull coal, and breaking with a conchoidal
fracture when viewed macroscopically, and that in thin section always
shows preserved cell structure of woody plant tissue, either of stem,
branch, or root. Same as anthraxylon. AGI
c. A coal composed of anthraxylon and attritus, in which the translucent
cell-wall degradation matter or translucent humic matter predominates.
AGI
d. A type of banded coal containing from 100% to 81% pure bright
ingredients (vitrain, clarain, and fusain), the remainder consisting of
clarodurain and durain. AGI
a. York. A smooth parting or joint in coal; a plane of cleavage.
b. The principal cleat in coal. Arkell
The candlepower of a light source divided by the area of the source, and
expressed in candles per square inch or candles per square foot.