a. A long, narrow elevation of the Earth's surface, generally sharp
crested with steep sides, either independently or as part of a larger
mountain or hill.
b. A long elevation of the deep-sea floor having steeper sides and less
regular topography than a rise. AGI
A runner or principal channel for molten metal. Standard, 2
A ridge built along a contour line of a slope to pond rainwater above it.
Nichols, 1
A horizontal, revolving, continuous vacuum filter. The surface is an
annular ring consisting of separate trays with vacuum and compressed air
attachments. The filtering surface is on the underside, the trays being
dipped into the tank of pulp to form the cake and then lifted out of it.
Liddell
Said of mine timbering when the sets are thrust out of line, or lean.
Dense-media system used to float coal away from shale, the latter falling
to the bottom of a wedge-shaped pool of separating fluid and being
withdrawn by a rising belt. Pryor, 3
To clean up after a cast, as when the scrap, slag, and iron is removed
from runners, troughs, and skimmers, and they are freshly clayed, loamed,
or sanded. Fay
A monoclinic mineral, Na2 Ca(MgFe+2 )5 Si8 O
22 (OH)2 ; amphibole group with Mg/(Mg+Fe2+ ) = 0 to
0.49 and Fe3+ /(Fe3+ +Al) = 0.7 to 1.0; forms a series
with magnesioriebeckite; fibrous; in soda-rich rhyolites, granites, and
pegmatites; crocidolite variety is blue asbestos, tiger eye is crocidolite
replaced by quartz. CF:glaucophane
The statement in thermodynamics that solution of a mineral tends to occur
most readily at points where external pressure is greatest, and that
crystallization occurs most readily at points where external pressure is
least. It is applied to recrystallization in metamorphic rocks with
attendant change in mineral shapes, such that mass is transferred from
contact points to pressure shadows resulting in reduced rock porosity. It
is named after the German physicist E. Riecke (1845-1915) although it was
actually discovered and described by Sorby in 1863. AGI
See:allophane
a. A natural shallows extending across a stream bed over which the water
flows swiftly and the water surface is broken into waves; a shallow rapids
of comparatively little fall. AGI
b. The lining of the bottom of a sluice, made of blocks or slats of wood
or stones, arranged in such a manner that chinks or slots are left between
them, into which heavy mineral grains fall and are held for recovery.
c. The raised portions of the deck of a concentrating table, that serve to
trap the heaviest particles. Syn:ripple
d. A device used to reduce the volume or weight of a sample consisting of
a thin metal plate on which is mounted a series of metal strips to guide
or deflect a small portion of the sample material into a separate
container. CF:sample splitter
e. Sample reducing device such as Clark riffler or Jones riffle, which
splits a batch sample of ground ore into two equal streams as it falls
across an assembly of deflecting chutes. See also:sludge sampler
CF:Jones splitter
Slats of wood nailed across the bottom of a cradle or other gold-washing
machine for the purpose of detaining the gold.
A device designed to reduce a sample of coal or ore to half its original
size. The box contains about 12 chutes discharging alternately to opposite
sides. The width varies according to the largest particle size. The volume
reduction is rapid for dry material of suitable fineness. Nelson
See:sample splitter
a. As used by drillers, a borehole that is following or has followed a
spiral or corkscrew course; also said of a drill core that has spiral
grooves appearing on its outside surface. Long
b. A drill hole, in rock, that has become three-cornered while drilling.
c. Applied to the three-cornered section of a hole drilled by hand. Though
the bit is supposed to be turned one-eighth after each blow, to insure a
circular hole, the majority of hand-drilled holes are three-cornered.
Stauffer
A cylinder with curved splines. Nichols, 1
A splined nut that slides back and forth on a rifle bar.
Nichols, 1
a. Working coal which was left behind over the waste. Nelson
b. The spiral grooving in the walls of a drill hole and/or on the surface
of a drill core. Long
c. A borehole following a spiraled course. Long
a. A regional-scale strike-slip fault, e.g., the San Andreas rift in
California, with offset measured in hundreds of kilometers. AGI
b. A trough or valley formed by faulting.
c. In quarrying, a direction of parting in a massive rock, such as
granite, at approx. right angles to the grain. CF:grain; hard way.
AGI
d. A narrow cleft, fissure, or other opening in rock (such as in
limestone), made by cracking or splitting. AGI
e. A planar property whereby granitic rocks split relatively easily in a
direction other than the sheeting (parallel to the surface of the Earth.)
AGI
f. A term used in slate quarrying to describe a second direction of
splitting less pronounced than slaty cleavage and usually at right angles
to it.
g. In sedimentary rocks, the horizontal plane of stratification, or the
bed of the rock. Stauffer
h. An obscure foliation, either vertical (or nearly so) or horizontal,
along which a rock splits more readily than in any other direction.
Syn:fault trace
i. A crack, such as in the mid-ocean ridges. MacCracken
One who separates blocks of mica into sheets and trims sheets preparatory
to processing. Also called full trimmer. DOT
The process of splitting hand-cobbed mica into sheets of usable
thicknesses. Skow