a. The operation of getting or working out the coal pillars formed by the
first working. Fay
b. In coal mining, unless the pillars of coal are left permanently to
support the surface, they are removed. This phase of mining is called the
second working or pillar working. When the pillars are removed, nearly all
of the coal has been recovered. CF:first working
working. See also:working the broken
A finely ground plastic clay that in proportions not lower than 6% gives
satisfactory green strength when used as a bond with molding sand.
Osborne
a. The act or process by which animals and plants transform mineral
material from solution into skeletal forms. AGI
b. A secondary structure formed of material deposited from solution within
a cavity in a rock, esp. a deposit formed on or parallel to the walls of
the cavity; e.g., a mineral vein, an amygdule, or a geode. The space may
be completely or only partly filled. CF:concretion
a. Capable of being cut with a knife without breaking off in pieces.
AGI
b. Said of a mineral that can be cut with a knife; e.g., argentite.
c. A physical property of minerals permitting shaving of curls with a
knife; e.g., gypsum. CF:malleable
A mineral is said to be sectile when it may be cut with a knife, but is
not malleable, for example, graphite. Nelson
a. A portion of the working area of a mine. BCI
b. Representation of features such as mine workings or geological features
on a vertical (or inclined) plane. A longitudinal section is parallel to
the strike of a vein or geologic plane. A cross section is perpendicular
to the strike. McKinstry
c. Detailed measurement, taken vertically, of a coal vein or of strata
embracing several veins. Hudson
d. A drawing or diagram of the strata sunk through in a shaft or inclined
plane, or proved by boring.
e. The local series of beds constituting a group or formation.
Standard, 2
f. A piece of land that is 1 square mile (2.59 km2 ) or 640 acres
(259 ha) in area forming one of the 36 subdivisions of a township in a
U.S. public-land survey. Webster 3rd
sectionalizing circuit breaker
See:circuit breaker
sectional mining belt conveyor
A belt conveyor so arranged that it can be lengthened or shortened by the
addition or the removal of interchangeable increments or parts.
NEMA, 2
A water tank built up of standardized pressed steel units having external
flanges that are bolted together in an assembly for varying sizes of tank.
Hammond
A conveyor that is lengthened or shortened by adding or removing
intermediate sections. NEMA, 1
A more or less loosely used term applied to the assistant mine foreman in
charge of an area, although used in law in some states in lieu of
assistant foreman and certified as such. BCI
See:section modulus
In anthracite and bituminous coal mining, a foreman who has complete
charge of a section of a mine. Syn:section man
See:caliper log
See:section foreman
The term pertains to the cross section of a beam. The section modulus with
respect to either principal central axis is the moment of inertia with
respect to that axis divided by the distance from that axis to the most
remote point of the section. The section modulus largely determines the
flexural strength of a beam of given material. Also called section factor.
Roark
A part of a rectifier unit with its auxiliaries that may be operated
independently. Coal Age, 1
A roller gate in which the roller is in the form of a sector of a circle
instead of being cylindrical. Hammond
Said of a process or event lasting or persisting for an indefinitely long
period of time, e.g., secular variation; progressive or cumulative rather
than cyclic. AGI
A relatively large, slow change in part of the Earth's magnetic field
caused by the internal state of the planet and having a form roughly to be
expected from a simple, but not quite uniformly polarized sphere.
AGI
A dike that has been intruded into hot country rock. Pegmatites and
aplites commonly occur in this mode. AGI