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trough plane

The plane that joins the troughs of a series of beds in a syncline;
generally, but not necessarily, the same as the axial plane.
See also:trough

trough vein

A trough-shaped ore deposit formed between sedimentary beds in the troughs
of synclinal structures.

trough washer

a. A washer applying the principle of alluviation in troughs.
BS, 5
b. In its simplest form, a trough washer is a sloping wooden trough, 1-1/2
to 2 ft (0.46 to 0.6 m) wide, 8 to 12 ft (2.4 to 3.7 m) long, and 1 ft
(0.9 m) deep, open at the tail end, but closed at the head end. It is used
to float adhering clay or fine material from the coarser portions of ore
or coal. A log washer.

troutstone

See:troctolite

trow

A wooden channel for air or water. Fay

troy ounce

One-twelfth of a pound of 5,760 grains (troy pound), or 480 grains. A troy
ounce equals 20 pennyweights, 1.09714 avoirdupois oz, or 31.1035 g. It is
used in all assay returns for gold, silver, and platinum-group metals.
Fay; Zimmerman

troy pound

A unit of weight that equals 5,760 grains, 12 tr oz, 240 pennyweights,
13.1657 avoirdupois oz, 0.82286 avoirdupois lb, or 373.2509 g.
Fay; Zimmerman

troy weight

These are the weights used for precious metals. The equivalents are 24
grains = 1 pennyweight; 20 pennyweights = 1 oz; 12 oz = 1 lb. The troy
grain is the same as the avoirdupois grain, but the ounce is larger on the
troy scale; 1 tr oz = 31.103 g; 1 avoirdupois oz = 28.35 g.
Anderson

truck

Any wheeled vehicle, usually self-propelled, used to transport heavy
articles or materials. In mining, usually applied to dump and/or
bottom-dump semitrailers used to transport mined waste and ore materials.
The number of types of these haulage units varies widely from the small
2-st (1.8-t) standard dump truck to the unit with capacity 200 st (181 t)
or greater. For larger stripping operations, where the haulage conditions
are not too rugged, a diesel tractor pulling a bottom-dump semitrailer of
capacity 40 to 60 st (36 to 54 t) is most common. The newer trucks are
equipped with power steering, power brakes, torque converters, and
automatic transmissions.

truck mixer

A concrete mixer, generally mounted on a lorry, or crawler-type tracks,
which mixes concrete during the journey from the batching plant to the
construction site. Hammond

truck roller

See:track roller

trudellite

A mixture of chloraluminite and natroalunite.

true azimuth

The azimuth measured clockwise from true north through 360 degrees .
AGI

true bearing

The bearing expressed as a horizontal angle between a geographic meridian
and a line on the Earth; esp. a horizontal angle measured clockwise from
true north. CF:magnetic bearing

true depth

The actual depth of a specific point in a borehole measured vertically
from the surface in which the borehole was collared.
Syn:true vertical depth

true dip

a. A syn. of dip, used in comparison with apparent dip. Syn:full dip
AGI
b. The angle at which veins, strata, etc., dip, as measured vertically
downward from the horizon along a line at right angles to the strike of
the veins, strata, etc.; also, the dip of a vein, strata, etc., as
determined on oriented core. See also:core orientation; oriented core;
apparent dip. Long
c. The maximum angle which an inclined bed makes with a horizontal plane.
It is the direction in which water would flow if poured on the smooth
upper surface of the bed at the outcrop. Also called dip.
See also:level course
d. See:three-dimension dip

true lode

See:fissure vein

true middlings

a. See:bone coal
b. Comparatively high-ash material so nearly homogeneous that its quality
cannot readily be improved by crushing and cleaning. BS, 5

true strain

The integral, over the whole of a finite extension, of each infinitesimal
elongation divided by the corresponding momentary length. It is equal to
loge (1 + epsilon ), where epsilon is the strain as ordinarily
defined. See also:strain

true stress

For an axially loaded bar, the load divided by the corresponding actual
cross-sectional area. It differs from the stress as ordinarily defined
because of the change in area due to loading. See also:stress
Roark

true vein

An occurrence of ore, usually disseminated through a gangue of veinstone,
and having more or less regular development in length, width, and depth.
See also:vein; fissure vein. Fay