a. Resistance, R, of a block of specified material in terms of units of
length 1 and cross section a. Unit volume is 1 cm3 of the
material concerned, and the resistivity measurement is made during
electrical prospecting. Specific resistance = (Ra) / 1. Pryor, 3
b. The electrical resistance offered to the passage of a current. Usually
expressed in ohm meters, which is the electrical resistance of a column of
fluid 1 m long and 1 m2 in cross section. Brantly, 1
c. The opposite of conductivity of an electrical current passing through
fluid-bearing rock formations. Wheeler, R.R.
d. The electrical resistance between opposite faces of a 1-cm cube of a
given substance. The unit of resistivity is ohm/centimeter. Hy
e. The reciprocal of conductivity. Syn:thermal resistivity
Strock, 2
Any electrical exploration method in which current is introduced into the
ground by two contact electrodes and potential differences are measured
between two or more other electrodes. AGI
a. A geophysical survey using the resistivity method. An assembly of
electrodes spaced at a constant distance is moved along profiles,
resulting in lateral variations in resistivity being shown. In favorable
terrain, the test shows the existence of faults that have thrown strata of
different resistivity against each other; similar relationships result in
the detection of an anticline, a syncline, or an underground channel.
Nelson
b. A survey by the resistivity method in which an array of electrodes is
moved along profiles to determine lateral variations in resistivity.
AGI
A device to provide resistance in an electric circuit, usually to limit
the current, dissipate energy, or provide heat. Kentucky
The replacement of the original topsoil at an opencast site on completion
of operations to allow the growing of crops.
See also:surface reinstatement
a. A measure of the ability of individual components, and of
remote-sensing systems, to distinguish detail or to define closely spaced
targets. AGI
b. The minimum size of a feature that can be detected.
See also:resolving power
c. The separation of a vector into its components. AGI
d. The sharpness with which the images of two closely adjacent spectrum
lines, etc., may be distinguished. AGI
e. In gravity or magnetic prospecting, the indication in some measured
quantity, such as the vertical component of gravity, of the presence of
two or more close but separate disturbing bodies. AGI
f. In seismic prospecting, the ability to indicate separately two closely
adjacent interfaces. AGI
g. The ability of an optical or radiation system to separate closely
related forms or entities; also, the degree to which they can be
discriminated. ASM, 1
In gravity and magnetic prospecting, the separation of two disturbing
bodies at which some obvious indication in a measured quantity of the
presence of two separate bodies ceases to be visible. AGI
A seismic reflection technique that involves the plotting of reflections
in time and the representation of horizontal distances along the section
in equivalent time units (obtained by dividing the true horizontal
distance by the sub-weathering velocity as determined from first-arrival
times). Once this transformation of the coordinate system is made,
migration is accomplished by swinging arcs of reflection times from
successive shot points and drawing lines which are tangent to the
respective arcs for the same events from adjacent shot points. For the
final mapping of migrated horizons in depth, the times are recorded
directly beneath the shot points. These times are converted to depths by
using the best available velocity information. Dobrin
In optical viewing, the minimum distance possible between two separately
distinguishable objects. Pryor, 3
a. A term denoting a variety of phenomena characterized by the abnormally
large response of a system having a natural vibration period to a stimulus
of the same, or nearly the same, frequency. AGI
b. A buildup of amplitude in a physical system when the frequency of an
applied oscillatory force is close to the natural frequency of the system.
AGI
A high-speed vibrating screen in which the applied force has a frequency
equal to the natural frequency of the suspended mass. In its basic form,
the vibrating frame of the resonance screen is a mass oscillating between
two compression springs, that alternately store and return this energy.
Nelson
Drilling that utilizes longitudinal vibration corresponding to the
resonant frequency of the drill string in order to "fluidize" the
sediments being sampled, thereby achieving efficient penetration.
Padan
A border of secondary minerals, produced by partial resorption and
recrystallization, surrounding an original crystal constituent of a rock.
Syn:corrosion border
A concentration of naturally occurring solid, liquid, or gaseous material
in or on the Earth's crust in such form and amount that economic
extraction of a commodity from the concentration is currently or
potentially feasible. USGS, 2
The determination of the shape, size, quality, quantity, and variability
of the geologic entity and the limits of variable geologic features, so as
to provide the information for synthesis of commonly subtle features into
an accurate, predictive description of the resource environment.
SME, 1
Particulates in a size range that permits them to penetrate deep into the
lungs upon inhalation. NSC, 2
a. A device (such as a gas mask) for protecting the respiratory tract
(against irritating and poisonous gases, fumes, smoke, dusts) with or
without equipment supplying oxygen or air. Webster 3rd
b. A device for maintaining artificial respiration. Webster 3rd
c. The mining-type respirator is a fitting that covers the nose and mouth
to prevent the wearer inhaling excessive quantities of dust. Tunnel miners
and workers at sinter plants and blast furnaces are issued respirators for
use where danger is known to exist. See also:filter-type respirator;
mask. Nelson
d. A device worn over the mouth or nose for protecting the respiratory
tract from noxious gases or dust.
a. A measure of the degree of protection provided by a respirator to the
wearer. FR 166
b. The ratio of the ambient concentration of an airborne substance to the
concentration of the substance inside the respirator at the breathing zone
of the wearer, a measure of the degree of protection provided by a
respirator to the wearer. ANSI
One complete breath--an inspiration followed by an expiration, including
any pause that may occur between the movements. Hunt
Referring to a degree of luster that reflects with brilliancy and gives
well defined images; e.g., hematite and cassiterite.
See:residual liquid