See:crocoite
A monoclinic mineral, PbCrO4 ; bright-red, yellowish-red, or
orange. Syn:red lead ore; crocoisite.
A term used in the Milford, NH, quarries to denote gneiss or any other
rock in contact with granite.
A name used for impure red ferric oxide pigments and polishing powders,
usually produced by heating iron sulfate containing calcium sulfate, lime,
or other inert filler. Also sometimes applied more generally to other
impure oxides of red or yellow color. CCD, 2
Brownish-yellow; mainly sodium or potassium thioantimonite; Na3 SbS
3 or K3 SbS3 . Obtained as a slag in refining
antimony. Webster 3rd
A monoclinic or trigonal mineral, Fe2+2 Fe3+
(SiFe3+ )O5 (OH)4 ; kaolinite-serpentine group; in
low-temperature hydrothermal veins.
A self-acting apparatus for running the hudges (boxes on runners) on
inclines in step coalbeds.
A borehole that has deviated beyond the allowable limit from the vertical
or from its intended course. AGI
A tetragonal mineral, Cu7 (Tl,Ag)Se4 ; massive or compact.
a. The outcrop of a lode; or the coal of poor quality at the outcropping
of a seam. See also:outcrop
b. Deprecated syn. of outcrop. --v. To appear at the surface of the
ground; to outcrop. AGI
a. Coal of inferior quality near the surface. CF:exposed coalfield
Fay
b. The coal next to the roof in a seam. Nelson
A caving in of the surface at the outcrop of the bed; caused by mining
operations. Applied also to falls occurring at points not on the outcrop
of the bed. Synonymous with day fall. Fay
A line following the outcrop. Austin
The mixture of crushing bodies, ore particles, and water being tumbled in
the ball mill.
a. Coal cutting beyond the normal cutting plane. Mason
b. Portions of a vein or other rock formation exposed at the surface.
Fay
c. See:outcrop
d. The operation of cutting off the end or ends of an ingot to remove the
pipe and other defects. CTD
The leaving of a small thickness of coal at the bottom of the seam in a
working place, usually in back water. The coal so left is termed "cropper
coal." Zern
The chief portion of tin ore separated from waste in the principal
dressing beneficiation operation.
See:crosscut
a. The top member of a drill derrick of H-frame from which the sheave
wheel is suspended. Long
b. Horizontal bar fitted between two drill columns on which a small
diamond or other type rock drill can be mounted. Long
The simultaneous exchange of material from magma to wall rock and vice
versa, tending to develop the same phases in both.
The horizontal roof member of a timber set on mine roadways, or a flat
supported by props on the face. See also:beam