a. A piece of metal connected to a cable that, when buried in the earth in
a shallow hole or lowered into a well, provides enough contact to permit
the passage of substantial electrical current into the surrounding earth.
AGI
b. A metal contact with the ground used to facilitate current flow through
the ground. AGI
Portion of the firing current bypassing part of the blasting circuit
through unintended paths. Atlas
An electric or electromechanical device that limits current amplitude;
duration of current flow; or total energy of the current delivered to an
electric blasting circuit. Atlas
a. Any one of numerous instruments for measuring the speed alone, or both
speed and direction, of flowing water, as in a stream or the ocean; it is
usually activated by a wheel equipped with a set of revolving vanes or
cups whose rate of turning is proportional to the velocity of the current.
AGI
b. An instrument, as a galvanometer, for measuring the strength of an
electric current. Standard, 2
A graphical representation of currents, usually by 1 degrees quadrangles,
using arrows of different lengths for the cardinal and intercardinal
compass points to show resultant drift and frequency of set for a given
period of time. Hy
Leic. A hole sunk from an upper to a lower portion of a thick seam of coal
through which the return air passes from the stalls to the airway.
Fay
Can. False affidavit of assessment work on mining claims. Hoffman
a. A sheet of brattice cloth hung across an entry in such a way as to
prevent the passage of an air current but not to hinder the passage of
mules or mine cars. In coal mines, curtains are used to deflect the air
from the entries into the working rooms and to hold the air along the
faces. They are usually made of a number of overlapping strips of heavy
curtain material, that should be of fireproof or fire-resistant material.
Syn:check curtain
b. Also called cover. Long
c. A thin sheet of dripstone hanging from the ceiling or projecting from
the wall of a cave. Schieferdecker
d. A rock formation that connects two neighboring bastions. AGI
e. One of a series of steps cut in a valley side and exaggerated by
cultivation. AGI
See:cover hole
a. A crystalline hydrocarbon, found in a form of greenish deposits from a
hot spring in California. Tomkeieff
b. A former name for idrialite.
A vector quantity calculated from torsion-balance data indicating the
shape of the equipotential surface. It points in the direction of the
longer radius of curvature. AGI
A chain coal cutter jib with the outer end bent upward or downward through
90 degrees . Thus, the machine can make a horizontal and also a vertical
cut in one operation. Curved jibs make coal preparation easier, but their
use is limited because of the excessive strain and wear on the cutter
chain. See also:turret jib; multicut chain. Nelson
A unit of waterflow or airflow that equals 1 ft3 /s (0.028 m
3 /s). Nelson
See:cowshut
A course of some compressible substance, such as soft wood, inserted
between more rigid material. In mine support, it can be placed between the
footwall or the hanging wall and the concrete, or internally in the
support. Spalding
A method of blasting in which an airspace is left between the explosive
charge and the stemming, or in which the shothole is of substantially
larger diameter than the cartridge. See also:controlled blasting
BS, 12
A style of faceting gems in which the finished gem is roughly rectangular
in outline but with gently outward curving sides and rounded corners.
Sinkankas
A mill that depends on purchased ores mostly or entirely for processing
rather than on its own organizational source.
Ore bought by a mill or smelter, or treated for customers. Hess