A pocket of very rich ore.
A gemstone that has been heated, stained, oiled, or coated; treated by
various types of irradiation, in order to improve or otherwise alter its
color; or laser-drilled to make flaws inconspicuous. Also, a stone that
has been preserved from dehydration, such as an opal whose cracks have
been filled with oil or other liquid; or one in which special effects have
been produced; e.g., amber with "spangles" (tension cracks).
See also:altered stone
The reduction of ores by any process whereby the valuable constituent is
recovered. Fay
Three standard lengths of drill rod or drill pipe connected together and
handled and stacked in a drill tripod or derrick as a unit length of rod
on borehole round trips. Also incorrectly spelled thribble; thrible;
tribble; trible. See also:stand; rod stand. Long
In mining, the system of dividing a ventilating current into three
coursings. Standard, 2
A trigonal mineral, AgAsS2 ; forms minute scarlet-vermillion
rhombohedral crystals; at Binenthal, Switzerland.
a. Visible projection of electrodeposited metal formed at a site of high
current density. ASM, 1
b. A thick log used as a prop in heavy ground. A prop, leg, or puncheon.
See also:treed
c. The fulcrum for the lever used in boring. Fay
d. A treelike aggregate of crystals, which forms from solution on a
suspended substrate that induces crystallization. Webster 2nd
A moss agate with dendritic markings resembling trees. Syn:tree stone
Supported by props, such as a mine roof. See also:tree
See:trilling
A hardwood plug drilled so as to allow a track spike to be driven through
it into a timber sleeper. Hammond
A high-grade uranium ore consisting of buried carbon trash that has been
replaced or enriched with uranium-bearing solutions. AGI
See:tree agate
A monoclinic mineral, 2[Ca2 Mg5 Si8 O22 (OH)
2 ] ; amphibole group with magnesium replaced by iron, and silicon
by aluminum toward actinolite; white to green; long-bladed or stout
prismatic crystals; may show columnar, fibrous, or granular masses or
compact aggregates; in low-grade metamorphic rocks such as dolomitic
limestones and talc schists; the nephrite variety is the gemstone jade;
the asbestiform variety is byssolite. CF:actinolite
Pertaining to or characterized by the presence of tremolite, as tremolitic
marble.
a. An area of intensely jumbled coal and associated beds. The contortions
contain sharp folds, thrusts, and glides. The mode or origin is
controversial. A theory that has gained some favor is that the disturbance
was initiated by a seismic shock, causing the coal seam and beds to crack
and heave. Later, lateral forces appear to have produced the final
complicated structures. Nelson
b. In coal mining, an area of complex folding, faulting, and gliding of
coal seams and associated rocks. It may be formed by seismic shocks during
the deposit's semicompacted state. AGI
a. A long, straight, commonly U-shaped valley or depression between two
mountain ranges. AGI
b. A narrow, steep-sided canyon, gully, or other depression eroded by a
stream. AGI
c. Any long, narrow cut or excavation produced naturally in the Earth's
surface by erosion or tectonic movements. Also, a similar feature produced
artificially, such as a ditch dug in prospecting for minerals. AGI
d. An elongated but proportionally narrow depression, with steeply sloping
longitudinal borders, one of which (the continental) rises higher than the
other (the oceanic). Trenches are the ends of unsymmetrical basins and lie
beside the continental border or island chains. Syn:marginal trench
AGI
e. A long but narrow depression of the deep-sea floor having relatively
steep sides. AGI
f. A long, narrow, intermontane depression occupied by two or more streams
(whether expanded into lakes or not), alternately draining the depression
in opposite directions. AGI
g. A narrow ditch. AGI
h. In geological exploration, a narrow, shallow ditch cut across a mineral
deposit to obtain samples or to observe character.
i. A long, narrow excavation in the ground, as a trench dug for the laying
of pipes. Crispin
j. A temporary scar in which a conduit is placed and then covered over.
CF:ditch
Excavation in which the width of operations and, generally, the depth are
limited. Trenching may be performed in any soil and will sometimes fall
into the category of limited-area, vertical excavation. Carson, 1
A self-propelled machine generally mounted on crawler tracks designed for
digging trenches or ditches. It is equipped with either a bucket ladder or
buckets mounted around the periphery of a circular wheel. Hammond
See:ripper
A slight refinement of grab sampling in which the material to be sampled
is spread out flat and channeled in one direction with a shovel, and the
material for the sample is taken at regular intervals along the channel.
The procedure is repeated with several other channels in different
directions until a sample of the proper size has been secured. Also called
channel sampling. Newton, 1