See:chalcopyrite
Field name for a drill tripod or derrick lamp, consisting of a metal
container with two spouts holding cotton wicks, on which burning oil gives
a very yellow light. Long
a. Impure yellow ocher. Webster 3rd
b. Loess of northern China.
Eng. The lower subdivision of the Aptian sponge gravel; Faringdon,
Berkshire. Arkell
Oxidized kimberlite of yellowish color found at the surface of diamond
pipes (e.g., South Africa), above the zone of blue ground. AGI
A division of the color scale. generally given as about 2,000 degrees F
(1,090 degrees C).
See:wulfenite
a. A mixture of limonite usually with clay and silica. Used as a pigment.
Webster 3rd
b. A moderate orange yellow that is yellower and darker than deep chrome
yellow. Webster 3rd
c. See:goethite; limonite.
See:carnotite; chalcopyrite.
A product resembling vaseline, but less homogeneous; produced from crude
ozokerite. Fay
See:chalcopyrite
See:orpiment
Eng. The basal part of the Permian, Durham. Arkell
See:sylvanite
A rejected syn. for ilvaite. CTD
a. The proportion of coal or ore obtained in mining; the product of a
metallurgical process; extraction; recovery. Fay
b. The percentage of "run-of-mine" material that is marketable.
Hudson
c. The amount of a product obtained from any operation expressed as a
percentage of the feed material. BS, 5
Steel arch installed in an underground mine. Arches are employed to
support loads caused by changing ground movement or faulted and fractured
rock. They are designed so that when the ground load exceeds the design
load of the arch as installed, yielding takes place in the joint of the
arch, permitting the overburden to settle into a natural arch of its own,
thus tending to bring all forces into equilibrium. Lewis
A soft floor that heaves and flows into open spaces when subjected to
heavy pressure from packs or pillars. See also:creep
An adjustable steel prop that incorporates a sliding or flexible joint
that comes into operation when roof pressure exceeds a set load or value.
See also:hydraulic chock; hydraulic prop. Nelson
A support that incorporates a sliding or flexible joint or stilt to
accommodate early pressure and thus delays damage and distortion of the
support. Friction or hydraulic devices may be used so that a support, when
subjected to a load above its set load, yields mechanically rather than by
distorting. See also:stilt
The difference between the actual yield of a product and the yield
theoretically possible (based on the reconstituted feed) of a product with
the same properties (usually percentage of ash). Also called washing
error. BS, 5