a. A general term for the direction or bearing of the outcrop of a
geological feature of any dimension, such as a layer, vein, orebody, fold,
or orogenic belt. CF:strike
b. The direction or rate of increase or decrease in magnitude of the
individual members of a time series of data when random fluctuations of
individual members are disregarded; the general movement through a
sufficiently long period of time of some statistical progressive change.
AGI
c. The direction or bearing of a bed, dike, sill, etc., or of the
intersection of the plane of a bed, dike, joint, fault, or other
structural feature with the surface of the ground. Fay
d. The direction or bearing of a fold or series of folds in rocks, of the
axes of the folds, of subsurface structures, of oriented or elongated
structures indicated by geological surveys, or of topographic features
that are consequent on the geologic structure. (As used in either sense,
the trend may or may not coincide with the strike, depending on the
structural relations at the place of observation.) CF:trace
Fay
An agitator with paddle-wheel-type arms; they are hollow, and the pulp
solution or air is discharged from nozzles on these arms, thus causing the
stirrer to rotate. Liddell
a. A subdivision of the American Ordovician sometimes considered as the
equivalent of the whole Middle Ordovician and sometimes restricted to a
portion of this series. Webster 3rd
b. Formerly, a division of the lower Silurian.
Agglomeration process sometimes used in coal cleaning and briquetting. Raw
coal crushed to minus 65 mesh is agitated with water and oil. Coal
agglomerates and ash-forming fraction are removed in aqueous solution.
Pryor, 3
a. A boring tool once used in the Kind-Chaudron shaft-sinking method.
Nelson
b. A boring machine used for shaft sinking through water-bearing strata.
A cutter loader for continuous mining in longwall faces. Its main cutting
unit is the trepanner wheel with cutting arms, one at each end of the
machine to enable it to cut in both directions on the face. Also fitted
are a vertical, back-shearing jib; a floor-cutting jib, duplicated to
enable cutting in either direction; and, if necessary, a roof-cutting
disk. The machine is used in conjunction with an armored flexible conveyor
on a prop-free front face; suitable for seams between 3 ft and 4 ft (0.9 m
and 1.2 m) thick, although it can work in thicker seams if the top coal
falls freely. Nelson
A type of boring in which an annular cut is made into a solid material,
with the coincidental formation of a plug or solid cylinder.
ASM, 1
A cutter loader in which the trepanner head is incorporated into the
shearer-loader while the cutting drum is retained to dress the floor and
back of the cut. Nelson
Working coal from the property or take of another coal mine owner.
See also:encroachment
a. A bridge, usually of timber or steel, that has a number of closely
spaced supports between abutments. Nichols, 1
b. A bent of timber, reinforced concrete, or steel, supporting a temporary
or permanent structure. Hammond
Person who unloads coke, limestone, and ore, and keeps bins poked down.
Fay
Allowance to purchaser for waste. Pryor, 3
An isometric mineral, NiFe2 O4 ; magnetite series of the
spinel group; black with greenish tint; at Barberton, Transvaal, South
Africa.
In crystallography, an element of symmetry characterized by a rotational
axis requiring three operations to return to identity. Isometric symmetry
contains four diagonal triads; trigonal symmetry requires a unique triad.
CF:threefold
A shallow hole, 2 to 3 ft (0.6 to 0.9 m) in diameter, put down to test
shallow minerals or to establish the nature and thickness of superficial
deposits and depth to bedrock. See also:test pit; pit sampling.
Nelson
The experimental shots and rounds fired in a sinking pit, tunnel,
opencast, or quarry to determine the best drill-hole pattern to use. This
is carried out when hard rocks are exposed. Nelson
A chemical compound crystallizing in three different crystal structures.
The characteristic feature of this cut lies in the fact that the drill
holes are arranged in zigzag. In this way a larger opening is obtained
because the drill holes can break out between the preceding rows. Each
vertical row of holes breaks out a layer. If the front holes do not break
out to the full depth, the burnt-out holes indicate the direction of break
for the following row of holes since the holes are arranged in zigzag. The
name, triangle cut, is due to the distribution of the holes at the working
face and the form of the initial opening. Fraenkel
A refraction type of seismic shooting used to facilitate the separation of
intercept times into constituent delay times. Three profiles can be laid
out as sides of a triangle. If intercept times are obtained at each of the
vertices of the triangle from shots at the other two vertices, one can
solve for the delay times at the three corners. Delay times along the
sides of the triangle can be determined by taking differentials in the
intercept times with respect to the delay times established at the
vertices. Dobrin
The strand core of a flattened strand rope. Hammond