a. A condition of the atmosphere of a mine so contaminated by gases as to
be unfit for respiration. Impure.
b. In a coal seam, a place where the seam was washed out during
deposition, leaving a barren area. Pryor, 3
A suction line in a tunnel ventilation system. Nichols, 1
Coke-oven gas or natural gas containing appreciable amounts of hydrogen
sulfide and similar contaminants. CCD, 2
The assemblage of marine organisms that attach to and grow upon underwater
objects. Hy
The point on any rail beyond which a wagon or mine car cannot proceed
without becoming an obstruction to another wagon or car traveling on the
intersecting rail. Nelson
a. Eng. A condition in which seams of coal disappear for a certain space
and are replaced by some foreign matter. See also:fault
b. The cutting out of portions of the coal seam by wash outs or barren
ground. CTD
a. To form in a mold, such as articles of cast iron, by melting the metal
and pouring; cast. Standard, 2
b. The name for the melting operation that the raw materials undergo in a
furnace. CTD
a. The lower, supporting part of an engineering structure, transmitting
the weight of the structure and its included loads to the underlying soil
or rock material. It is usually below ground level. AGI
b. A term that is sometimes applied to the upper part of the soil or rock
mass in contact with, and supporting the loads of, an engineering
structure; the subsoil. AGI
c. Mid. The shafts, machinery, building, railways, workshop, etc., of a
mine, commonly called a plant.
d. The ground upon which a structure or substructure is supported.
Taylor
e. The lower part of a structure that transmits the load to the earth.
ASCE
f. The base and/or the underlying support, either natural or artificial,
on which a building, dam, or other structure is constructed. Long
g. See:base rock
A fastener for connecting a structure or machine to a permanent base.
See also:anchor bolt
A construction in a sinking shaft that will provide support for the
concrete lining. It consists of a wedge-shaped excavation around the shaft
in solid ground that is filled up completely with wet concrete. Steel
shuttering is used and the concrete is filled in behind. Also called
foundation canch; foundation crib; walling curb. See also:curb;
permanent shaft support. Nelson
A branch of soil mechanics involving the drilling and testing of the
deposits underlying a proposed foundation. It includes the estimation of
bearing capacities, settlements, and the most suitable type of foundation
for the prevailing soil conditions. See also:bearing capacity;
depth of soil exploration. Nelson
Testing in which boreholes are drilled for the purpose of obtaining
samples by means of which the characteristics of overburden and/or the
rock on which the foundation of a structure will rest can be determined.
Long
See:collapse breccia
The act or process of casting metals. Fay
Sand used by founders in making molds for castings. See also:fire sand
See:roller rock bit
An axis of symmetry requiring four repetitions to complete 360 degrees and
return to identity. Syn:tetrad
A mill that contains four rolls arranged one above the other; i.e., two
small-diameter working rolls supported by larger diameter back-up rolls
above and below. Osborne
A crystal twin consisting of four individuals; characteristic twinning
exhibited by some varieties of authigenic microcline. CF:trilling;
fiveling; eightling.
An orthorhombic mineral, PbU4 O13 .4H2 O ; strongly
radioactive; in pegmatites as an alteration product of uraninite.
Squared timber frame used in underground driving to give all around
support to weak ground. A cap is supported by two posts on a sill-piece or
sill. See also:timber set; three-piece set. Pryor, 3