Eng. The main cleavage planes or joints in a coalbed. SMRB
Aust. A direction at right angles to the main cleat or facing; i.e., the
length of a bord.
A coal drivage in the pillar-and-stall method of working. Nelson
The marginal portion of an igneous intrusion, which differs in texture and
composition from the main body of the intrusion, possibly because of more
rapid cooling or assimilation of material from the country rock.
AGI
a. A main gate leading and at right angles to a bord face. TIME
b. York. A heading driven generally to the rise, out of which stalls are
opened and worked.
a. A heading driven parallel to the natural joints. Fay
b. The space excavated in driving a bord. Used in connection with the
ridding of the fallen stone in old bords when driving roads across them in
pillar working; thus, "ridding across the old bordroom." Zern
c. Eng. The width across an old bord. Fay
A repairer who cleans and erects supports in old workings in the
bord-and-pillar method of coal mining. Nelson
York. A system of working coal. First, the main levels are started on both
sides of the shaft and carried toward the boundary. Second, the bord gates
are worked in pairs to the rise and continued as far as the boundary, or
to within a short distance of a range of upper levels and other bord
gates. Lastly, the whole of the pillars and remaining coal are worked out
downhill to within a few yards of the levels, and ultimately, all the coal
between the levels is removed. Fay
Eng. The direction of a place or a face being taken at right angles to the
main cleavage planes of a seam. SMRB
The direction at right angles to the main cleavage planes. In some mining
districts it is termed "on face." Zern
a. A tunnel, esp. while being excavated.
b. A circular hole made by boring. Long
a. A hole with a drill, auger, or other tools for exploring strata in
search of minerals, for water supply, for blasting purposes, for proving
the position of old workings and faults, and for releasing accumulations
of gas or water.
b. A circular hole made by boring; esp. a deep hole of small diameter,
such as an oil well or a water well. Also called well bore.
See also:hole
Explosives loaded in the hole bottom at a weight or density in excess of
the main charge in order to fragment difficult to break rock or to break
an excessive toe burden.
Cable designed for vertical suspension in a borehole or shaft and used for
power circuits in the mines. (A borehole cable in mining may also be a
cable containing signal, telephone, or control circuits.)
A steel pipe lining used in a borehole, particularly when passing through
loose, running ground. Flush-jointed casing that is smooth inside and
outside may be either screwed or welded. Nelson
A device for measuring the change in diameter of a hole.
A record, made by the driller or geologist, of the rocks penetrated in the
borehole. In the laboratory, a more detailed log is prepared giving
particulars relating to lithology, paleontology, water analysis, etc.
See also:electric log; well log. Nelson
The determination of the physical, electrical, and radioactive properties
of the rocks traversed by a borehole. BS, 9
The extraction of minerals in the liquid or gaseous state from the Earth's
crust by means of boreholes and suction pumps. Boreholes are used for
mining petroleum, and for the extraction of liquid solutions of salt,
sulfur, etc. See also:well
The pressure that the hot gases of detonation exert on the borehole wall.
It is primarily a function of the density of the explosive and the heat of
explosion. Syn:gas pressure
a. Any pump that can be suspended in a borehole; usually a centrifugal
pump suspended in a borehole by its pipe range and driven by a shaft
inside the pipe. BS, 10
b. A centrifugal pump, electrically driven, and designed in the form of a
vertical narrow chamber. It may be used to provide water, for dewatering
purposes, or for borehole mining. See also:sinking pump
submersible pump. Nelson