A spray device for producing a very fine mist for the suppression of
airborne dust in mines. It is normally operated by compressed air.
Syn:jet mixer; line oiler.
A yellow or brown variety of romeite containing fluorine.
See also:romeite
That portion of the subsurface water adhering to the pore walls. It is
assumed to be equal in quantity to the pellicular water, and it is
measured by specific retention. AGI
Planned rate of ore extraction from mineral deposit. Pryor, 3
A light-green, magnesium-rich clay mineral, named from its occurrence at
Attapulgus, GA, where it is quarried as fuller's earth. Crystallizes in
the monoclinic system. Syn:palygorskite
A signaling system that operates between the surface lamp room and the
underground office, indicating the workers in attendance at the beginning
of the shift. See also:self-service system
a. A reduction in the amplitude or energy of a signal, such as might be
produced by passage through a filter. AGI
b. A reduction in the amplitude of seismic waves, as produced by
divergence, reflection and scattering, and absorption. AGI
c. That portion of the decrease in seismic or sonar signal strength with
distance that is dependent not on geometrical divergence, but on the
physical characteristics of the transmitting medium. CF:damping
AGI
In a sediment, the water-content boundaries between the semiliquid and
plastic states (known as the liquid limit) and between the plastic and
semisolid states (known as the plastic limit).
See also:consistency limits
AGI
A proposed particle-size scale or grade scale for the classification of
sediments based on a decimal system beginning with 2 mm. The limits of the
subclass are obtained by taking the square root of the product of the
larger grade limits. The subdivision thus made follows the logarithmic
rule. This is the accepted European standard for classification of
particle size. AGI
A method for determining the plasticity of clay in terms of the difference
between the water content when the clay is just coherent and when it
begins to flow as a liquid. Dodd
The relation of some directional feature in a rock to the horizontal
plane. The attitude of planar features (bedding, foliations, joints, etc.)
is described by the strike and the dip. The attitude of a linear feature
(fold axis, lineation, etc.) is described by the strike of the horizontal
projection of the linear feature and its plunge. AGI
A bright coal (composed of anthraxylon and of attritus in which the
translucent cell-wall degradation matter or translucent humic matter
predominates) in which the ratio of anthraxylon to attritus is less than
1:3. See also:anthraxylous coal; attritus. AGI
a. The act of wearing and smoothing of rock surfaces by the passage of
water charged with sand and gravel, by the passage of sand drifts, the
descent of glaciers, etc. AGI
b. The wear and tear that rock particles in transit undergo through mutual
rubbing, grinding, knocking, scraping, and bumping, with resulting
comminution in size. CF:abrasion
a. Mill that grinds abrasively, using rubbing action rather than impact
shattering to disintegrate material. Pryor, 3
b. A disintegrator depending chiefly on impact to reduce the particle size
of the charge. Attrition mills are sometimes used in the clay building
materials industry to deal with the tailings from the edge-runner mill.
Dodd
Wear of abrasive grains in grinding such that sharp edges gradually become
rounded. A grinding wheel that has undergone such wear usually has a
glazed appearance. ASM, 1
a. A composite term for dull gray to nearly black coal components of
varying maceral content, unsorted and with fine granular texture, that
forms the bulk of some coals or is interlayered with bright bands of
anthraxylon in others. It is formed of a tightly compacted mixture of
altered vegetal materials, esp. those that were relatively resistant to
complete degradation. CF:attrital coal
introduced by R. Thiessen in 1919. AGI
b. Thin bands of dull coal interlaminated with the bright, glossy coal
bands called anthraxylon. Microscopically it consists of intimately mixed,
tightly compacted remains of varied morphological form and origin.
Attritus is a collective term, not directly comparable with any one of the
microlitho types of the Stopes-Heerlen nomenclature but consists of an
intimate association of varying proportions of macerals of the vitrinite,
exinite, and inertinite groups. It is present in practically all types of
coal. In bright-banded coal it is secondary in importance to anthraxylon,
but in splint coal it is the dominant component, and nonbanded attrital
coals consist entirely of attritus. IHCP
c. The dull-gray to nearly black, frequently striped portion of material
that comprises the bulk of some coals, and the alternating bands of bright
anthraxylon in well-banded coals. It was derived from all sorts of
comminuted and macerated plant matter, esp. from the plants that were more
resistant to complete decomposition. It consists of humic degradation and
opaque, charred, resinous, and mineral matter; fats, oils, waxes,
cuticles, spores, arid spore exines, and other constituents of the plants
forming the coal. AGI
d. Coal components consisting of a mixture of microscopic fragments of
vegetable tissues. It is classified into opaque attritus and transparent
attritus. Generally, it corresponds to cull coal or durain.
Tomkeieff
Any frequency corresponding to a normal audible sound wave (ranges roughly
from 15,000 to 20,000 Hz). Hunt
A monoclinic mineral, Al2 (PO4 )(OH)3 .
In foliate metamorphic rocks such as schists and gneisses, large
lenticular mineral grains or mineral aggregates having the shape of an eye
in cross section, in contrast to the shapes of other minerals in the rock.
See also:augen structure
A general term for a gneissic rock containing augen.
See also:cataclasite
A metamorphic rock characterized by recrystallized minerals occurring as
augen or lenticles parallel to and alternating with schistose streaks.
See also:mylonite gneiss