a. A space or division in a shaft formed by cross buntons. The main
compartments in a winding shaft are two for cages or skips.
See also:rectangular shaft
b. One section or unit in a coal- or mineral-treatment plant.
Nelson
a. An instrument or device for indicating horizontal reference directions
relative to the Earth by means of a magnetic needle or group of needles;
specif. magnetic compass. Also, a nonmagnetic device that serves the same
purpose; e.g., a gyrocompass. AGI
b. A simple instrument for describing circles, transferring measurements,
or subdividing distances; usually consisting of two pointed, hinged legs
(one of which generally having a pen or pencil point) joined at the top by
a pivot. AGI
c. A Maas or other compass device formerly used in borehole-survey work.
Long
a. The difference, expressed in degrees, between the direction a magnetic
compass needle points and true or astronomical north. This is termed
magnetic declination. Long
b. Differences, expressed in degrees, between magnetic north directions
and the direction a magnetic compass points, owing to local magnetic
interferences. This is termed magnetic deviation. Long
Direction as indicated by a compass without any allowances for compass
error. The direction indicated by a magnetic compass may differ by a
considerable amount from the true direction referred to a meridian of the
Earth. Hunt
The four principal points of the compass--north, east, south, and
west--are called the cardinal points. Midway between the cardinal points
are the intercardinal points--northeast, southeast, southwest, and
northwest. Midway between each cardinal and intercardinal point is a point
with a name formed by combining that of the cardinal and intercardinal
point, the former being placed first, as north-northeast, east-northeast,
and so forth. Midway between the points already indicated are points
bearing the name of the nearest cardinal or intercardinal point followed
by the word "by" and the name of the cardinal point in the direction in
which it lies, as north by east, northeast by north, and so forth. In all,
there are 32 points separated by intervals of 11-1/4 degrees . Each of
these intervals is subdivided into quarter points. Hunt
Random error equally likely to be plus or minus, and if of small
dimensions, reasonably likely to be compensated by further errors. In
contrast, systematic or biased errors all fall on the same side of correct
measurement and may therefore accumulate and produce serious
discrepancies. Pryor, 3
Balance weight ropes having direct connection with hoisting ropes.
Hammond
A procedure for determining the voltage difference between two points in
the ground by balancing against a voltage that is adjusted in phase and
amplitude to effect the compensation. See also:compensator
An instrument to determine the voltage difference between two points in
the ground by the compensation method. Syn:accessory plate
The ability of a current of water or wind to transport detritus, in terms
of particle size rather than amount, measured as the diameter of the
largest particle transported. It depends on velocity: a small, but swift
stream, e.g., may have greater competence than a larger but slower-moving
stream. Adj: competent. AGI
a. Strata or rock structure combining sufficient firmness and flexibility
to transmit pressure and, by flexure under thrust, to lift a
superincumbent load. Standard, 2
b. Streams able to transport debris of a given size. Standard, 2
c. Rock formations in which no artificial support is needed to maintain a
cave-free borehole. Long
d. Rock capable of withstanding an applied load under given conditions
without falling or collapsing. See also:incompetent
a. A rock formation that, because of massiveness or inherent strength, is
able to lift not only its own weight but also that of the overlying rock.
AGI
b. A bed that has a physical characteristic such that it responds to
tectonic forces by folding and faulting, rather than by crushing and
flowing. A competent bed is relatively strong, an incompetent bed,
relatively weak. See also:incompetent bed
a. Rock that, because of its physical and geological characteristics, is
capable of sustaining openings without structural support, except pillars
and walls left during mining.
b. Rock formations in which no artificial support is needed to maintain a
cave-free borehole. Long
c. Rock capable of withstanding an applied load under given conditions
without falling or collapsing. Long
See:rock fracture
Associated dikes (or other minor intrusions) composed of different, but
related rocks, regarded respectively as leucocratic and melanocratic
differentiation products from a common magma; e.g., aplite and
lamprophyre; bostonite and camptonite. Holmes, 2
In crystallography, two forms combined geometrically to produce a form
having higher symmetry; e.g., two equally developed rhombohedra of quartz
resembling a hexagonal bipyramid.
Occurs when the products of combustion leaving the furnace or appliance do
not contain any gaseous combustible matter. Nelson
a. A large-scale field association or assemblage of different rocks of any
age or origin, having structural relations so intricately involved or
otherwise complicated that the rocks cannot be readily differentiated in
mapping, e.g., a volcanic complex. See also:igneous complex;
basement complex. AGI
b. A unit that consists of a mixture of rocks of two or more genetic
classes, i.e., igneous, sedimentary, or metamorphic, with or without
highly complicated structure; example: Franciscan Complex. AGI
c. Said of an ore that carries several metals difficult to extract.
von Bernewitz
d. An assemblage of rocks of any age or origin that has been folded
together, intricately mixed, involved, or otherwise complicated.
Stokes
Those having many crystal forms and faces.
A fold that is cross-folded; i.e., a fold, the axial line of which is
folded.
a. An ore containing two or more metals, as lead-zinc ore. Many complex
ores are difficult or costly to treat, e.g., gold ore with arsenic or
antimony minerals, or ore composed almost entirely of several sulfide
minerals.
b. An ore containing several metals. Bateman, 2
c. Ores named for two or more valuable metals such as lead-zinc ores,
gold-silver ores, etc. Newton, 1
d. This term has no precise meaning. It generally signifies an ore that is
difficult or costly to treat because of the presence of unusual minerals,
e.g., a gold ore with aresenic and antimony minerals, or an ore containing
two or more metals, or ore composed almost wholly of several sulfide
minerals. Nelson