a. The recovery of coal or ore from a mine, or part of a mine, that has
been abandoned because of fire, water, or other cause.
b. Restoration of mined land to original contour, use, or condition.
See:cleaner cell
A circuit breaker that recloses automatically as soon as the demand for
current becomes equal to or less than that for which the circuit breaker
is set. Zern
An 8-h or 10-h time-weighted average or ceiling of exposure to coal dust
concentration; recommended by NIOSH and based on an evaluation of the
health effects data. NIOSH
a. An arkose consisting of consolidated feldspathic residue (produced by
surface weathering of an underlying granitic rock) that has been so little
reworked and so little decomposed that upon cementation the rock looks
very much like the granite itself. It has a faint bedding, an unusual
range of particle sizes (unlike the even-grained or porphyritic texture of
true granite), and a greater percentage of quartz than is normal for
granite. Syn:reconstructed granite
b. A conglomerate that has been recrystallized by metamorphism into a rock
that simulates granite, as in the Lake Superior region. CF:meta-arkose
A rock produced in place by the cementation of the fragmental products of
surface weathering; e.g. a recomposed granite. The term has been applied
to a rock of intermediate character straddling an unconformable surface
between the breccia of the lower formation and the conglomeratic base of
the upper formation. AGI
a. A general, exploratory examination or survey of the main features (or
certain specific features) of a region, usually conducted as a preliminary
to a more detailed survey; e.g. an engineering survey in preparing for
triangulation of a region. It may be performed in the field or office,
depending on the extent of information available. AGI
b. A rapid geologic survey made to gain a broad, general knowledge of the
geologic features of a region. AGI
A map incorporating the information obtained in a reconnaissance survey
and data obtained from other sources.
See:pilot sampling
To make a reconnaissance of; esp. to make a preliminary survey of an area
for military or geologic purposes. AGI
See:pressed amber
An imitation turquoise made of finely powdered ivory which is deposited in
a solution of copper. Fay
The modernization of underground roadways, transport, ventilation systems,
and the layout of mine workings. It may include modernization of shafts
and winding and also the improvement of surface handling and cleaning or
washing equipment. See also:mechanization
An isochemical change in a crystal structure in which chemical bonds are
broken and reformed, e.g., tridymite-quartz or diamond-graphite.
CF:dilational transformation; displacive transformation;
rotational transformation; phase transformation.
See:record hole
The first borehole drilled in an area that is cored so that a detail
record of the formations penetrated can be obtained. Also called test
hole. See also:stratigraphic hole
A gage which automatically records the level of water in a stream or tank,
or velocity and pressure in a pipe. It is operated by a float or by a
submerged air tank fitted with a rubber diaphragm. Hammond
Heavy-duty shaking table used to treat relatively coarse sands. Shaking is
by double-link eccentric motion, with longer and slower throw than with
Wilfley type of table. Pryor, 3
a. To restore a mine or a part of a mine that has been damaged by
explosion, fire, water, or other cause to a working condition. Fay
b. See:recovery
The true mill-head grade of an ore-stream in percent, ounces, or parts per
million of a metal or mineral, less extractive metallurgical losses; the
proportion of an ore material actually recovered.