Sieves are standardized in British Standard 410 and sieve size diamond
powders in British Standard 1987. Osborne
See:poikiloblastic
a. Grading in accordance with particle size and shape by means of sieves
or screens. Pryor, 3
b. The operation of shaking loose materials in a sieve so that the finer
particles pass through the mesh bottom. By using a number of sieves with
different meshes, the particles can be graded according to size.
Syn:sifting
See:sieving
a. A bob or weighted string hung from an established point in the roof of
a room or entry, to give direction to the miners driving the entry or
room. Fay
b. A bearing or angle taken with a compass or transit when making a
survey. Fay
c. Any established point of a survey. Fay
The distance from which an object at eye level remains visible to an
observer. Hammond
A stake or mark used by a driller as a means of setting and orienting a
drill so that the borehole can be drilled to follow a predetermined
directional course. Long
Established compass or transit course for alignment of working places,
usually marked on the roof. BCI
Bobs or weighted strings hung from two or more established points to give
direction to miners driving a chamber or gangway. Hudson
A triclinic mineral, FeAl2 (PO4 )2 (OH)3 .7H
2 O ; paravauxite group.
See:total heat
The arrangement in use for transmitting signals to stop or start
conveyors, rope haulages, locomotives, winders, etc.
See also:face signaling; loudspeaker face telephone. Nelson
See:mine fan signal system; hoist signal system.
An anomaly that is related to ore and that can be used as a guide in
exploration. See also:geochemical anomaly
a. A term suggested by Lamplugh (1902) for a conglomerate consisting of
surficial sand and gravel cemented into a hard mass by silica. Examples
occur in post-Cretaceous strata of the United States. AGI
b. A siliceous duricrust. Etymol: "sil"iceous + con"crete." CF:calcrete;
ferricrete. AGI
A roller-type chain in which the sprockets are engaged by projections on
the link side bars. Nichols, 1
a. The French term for flint. AGI
b. Silica; esp. quartz, such as a pure or finely ground form for use as a
filler. AGI
c. An old term formerly applied to a hard, dense rock, such as basalt or
compact limestone. Etymol: Latin, hard stone, flint, quartz. The term was
used by Pliny for quartz. AGI
a. An igneous rock composed essentially of primary quartz (60% to 100%),
e.g., a quartz dike, segregation mass, or inclusion inside or outside its
parent rock. AGI
b. The French term for chert; specif. chert occurring in calcareous beds.
See also:chert
The chemically resistant dioxide of silicon, SiO2 ; occurs
naturally as five crystalline polymorphs: trigonal and hexagonal quartz,
orthorhombic and hexagonal tridymite, tetragonal and isometric
cristobalite, monoclinic coesite, and tetragonal stishovite. Also occurs
as cryptocrystalline chalcedony, hydrated opal, the glass lechatelierite,
skeletal material in diatoms and other living organisms, and fossil
skeletal material in diatomite and other siliceous accumulations. Also
occurs with other chemical elements in silicate minerals.