A mineral structure of fibers or columns that cross to resemble a net;
e.g., rutile. See also:reticulate
Veins that cross each other, forming a network. See also:stockwork
See:mesh texture
A set of intersecting very fine lines, wires, etc., in the optical focus
of an optical instrument. It is also referred to as graticule.
See also:collimation line
An extremely attenuate pyroclastic rock consisting of glass threads which
join a series of points forming a polyhedral space lattice. It is formed
from pumice by the collapse of the walls of adjacent vesicles and the
retraction of the liquid into threads which form the perimeters of the
former polygonal faces. The threads are usually of triangular cross
section, indicating chilling, before rounding could take place. Such rock
has generally been known by Dana's name, thread-lace scoria.
See also:thread-lace scoria
Netted; reticulate; said of the boundaries of some vein quartz (rare).
Hess
Bitumen contained in meteorites. The name indicates that this substance on
distillation gives rise to resin, in contrast to kerogen which on
distillation gives rise to oil. Tomkeieff
A massive, honey-yellow or greenish variety of serpentine with a waxy or
resinous luster.
A light brown resinous substance found in brown coal in Devonshire,
England. Tomkeieff
A variety of fossil resin found as rodlets secreted in canals or ducts of
coal-forming plants.
A microscopical constituent of torbanite consisting of translucent
orange-red discs. CF:gelosite; humosite; matrosite. Tomkeieff
A wave passing back through burned or burning explosion gases toward the
origin, at the rate of a sound wave through gases of like temperature,
from a point in the explosion wave, usually of high pressure, to an area
of lower pressure. Rice, 2
a. A vessel used for the distillation of volatile materials, as in the
separation of some metals and the destructive distillation of coal.
ASM, 1
b. A long semicylinder, now usually of fireclay or silica, for the
manufacture of coal gas. Webster 3rd
c. See:amalgam retort
a. Removing the mercury from an amalgam by volatizing it in an iron
retort, conducting it away, and condensing it. Fay
b. In the sulfur industry, synonymous with sublimation. Fay
A person who operates a hydraulic press in which fireclay retorts, used in
smelting zinc ores, are made. DOT
The mechanism by which a dipper shovel bucket is pulled back out of the
digging. Nichols, 1
A type of deflecting wedge that can be retrieved after the deflected drill
hole has been completed. Syn:retrievable wedge
See:crowding
To work rooms or pillars to finish coal or ore extraction in an area that
has been penetrated to its limits by advance work; workings are generally
in the opposite direction of advance work and allow the area to be
abandoned as finished. BCI
a. First driving haulage road and airways to the boundary of a tract of
coal and then mining it in a single face without pillars back toward the
shaft. Fay
b. See:longwall retreating
a. A method of working a mine that is designed to allow a stope to cave
soon after it is worked out, thus relieving the weight on the supports in
adjacent stopes. Lewis
b. A method of extracting coal or ore by driving a narrow heading to the
boundary, then opening out a face and working the deposit backwards
towards the shaft, drift, or main entry. See also:longwall retreating
Nelson
c. A stoping system in which supporting pillars of ore are left while
deposit is worked outward from shafts toward the boundary, the pillars
being removed (robbed) as the work retreats toward the shaft; the
unsupported workings are abandoned and left to cave in. Pryor, 3
d. A system of robbing pillars in which the line of pillars being robbed
retreats or moves from the boundary toward the shaft or mouth of the mine.
See also:longwall retreating