A type of wheel conveyor making use of a series of skate wheels mounted on
common shafts or axles or mounted on parallel spaced bars on individual
axles.
Crystals that develop under conditions of rapid growth and high degrees of
supersaturation so that atoms or ions are added more rapidly to edges and
corners of growing crystals, resulting in branched "dendrites" or hollow
stepped depressions, "hoppers." Ice on windowpanes (frost) and pyrolusite
on agate (moss agate) are dendrites; halite and gold may form hopper
crystals. CF:dendrite; hopper crystal.
Hollow or imperfectly developed crystals formed by rapid crystallization.
Fay
Consists of a continuous wood frame with sheathing planks placed
vertically at intervals, usually of about 4 ft (1.2 m), behind it. Used
where the banks consist of compacted, stable soils, primarily to prevent
initial yield at the top. CF:close sheathing; tight sheathing.
Carson, 1
A temporary method of supporting a circular shaft sinking. It consists
essentially of iron curbs or rings. Each ring consists of segments of
wrought iron, 3 to 5 in (7.62 to 12.7 cm) deep, 5/8 to 7/8 in (1.59 to
2.22 cm) thick, and from 6 to 8 ft (1.82 to 2.44 m) in length. The
segments are bent to the curvature of the shaft and bolted together, each
ring being suspended from the ring above. Laggings or backing deals are
wedged behind the rings. Every fourth ring or so is supported on steel
strata bolts driven into holes drilled in the rock sides.
See also:temporary shaft support
Mild steel strip, often of Bessemer steel, from which tubes are made by
drawing it through a welding bell, at welding temperature, to produce
butt-welded or lap-welded tubes or pipes. See also:butt weld
Hammond
Wrought iron rolled into flat bars suitable for making pipe.
Mersereau, 2
a. An old English term meaning, variously, thin layers of micaceous
sandstone in the Coal Measures, a thin ferruginous sandstone crowded with
fossils, or a hard gritty clay used in making firebricks.
b. Eng. Thin layers of sandstone in the Keuper Marls, Leicestershire, and
Derbyshire coalfield. Arkell
c. Micaceous sandstones in the Coal Measures of Wales and the Midlands.
Arkell
d. Eng. A thin band of ferruginous, micaceous rock, crowded with fossils,
Middle Lias, Sutton Basset, Rutland. Arkell
Mid. Hard, thin-bedded sandstone.
a. An irregular discontinuous vein striking out from the principal vein in
an uncertain direction, lying in a slanting and irregular position.
b. The angled support from which an arch is sprung. AISI
On a horizontal angle, or in an oblique course or direction.
Nichols, 1
A roller conveyor having a series of rolls skewed to direct objects
laterally while being conveyed.
In coal sampling, a lack of symmetry in the particle-size distribution. It
is a tendency of the observed data to extend farther to one side of the
average than to the other. Mitchell
See:bloomery
a. Stones cut to form the coping of a gable. Arkell
b. Cracks on irregular joints in a mine, sometimes indicating danger from
falls. Arkell
A hypothetical garnet "molecule," Fe3 Fe2 (SiO4 )
3 .
A vague remnant of country rock in granite, obscured by the process of
granitization. CF:schlieren; xenolith. AGI
a. An iron shoe or clog attached to a chain and placed under a wheel to
prevent its turning when descending a steep hill; a drag.
Webster 3rd
b. An arrangement upon which certain coal-cutting machines travel along a
working face. Fay
c. A metal slide placed under a mine car wheel temporarily to restrict the
speed of a trip on a descending grade. BCI
d. A metal plate placed under a shortwall cutting machine to control it
while cutting. BCI
e. The sledlike platform forming the base on which a machine or structure
is set and slid or skidded into position; also, the sled runner,
bottom-most part of the base of a drill or other machine. Long
A term applied when a drill or other machine is attached permanently to a
skid. Long
A method of transporting miners to the coal face in special chairs that
move continuously on an endless conveyor. Nelson
A gating arrangement designed to prevent the passage of slag and other
undesirable materials into a casting. ASM, 1