A seismometer with response linearly proportional to the acceleration of
earth materials with which it is in contact. AGI
See:index contour
A charge of explosives or blasting agent receiving an impulse from an
exploding donor charge. Syn:receptor
a. Applied to minerals occurring in small quantities in a rock. The
presence or absence of these minor minerals does not affect the
classification or the naming of the rock. Holmes, 2
b. Fragments derived from previously solidified volcanic rocks of related
origin; i.e., the debris of earlier lavas and pyroclastic rocks from the
same cone. See also:accessory mineral
c. Said of pyroclastics that are formed from fragments of the volcanic
cone or earlier lavas; it is part of a classification of volcanic ejecta
based on mode of origin, and is equivalent to resurgent ejecta.
CF:auxiliary
See:trace element
Any mineral the presence of which is not essential to the classification
of the rock. Accessory minerals generally occur in minor amounts; in
sedimentary rocks they are mostly heavy minerals. CF:essential mineral
Syn:accessory
a. The quartz wedge inserted in the microscope substage above the
polarizer in order to estimate birefringence and to determine optical sign
of uniaxial minerals. CF:quartz wedge
b. The selenite plate that gives the sensitive tint of a specimen between
crossed nicols. Pryor, 3
c. The mica plate that retards yellow light. Pryor, 3
d. In polarized-light microscopy, an optical device that may be inserted
into the light train to alter light interference after passage through, or
reflection by, a crystalline material; e.g., quartz wedge, mica plate,
gypsum plate, or Bertrand lens.
e. In polarized-light microscopy, an optical compensator that may be
inserted into the light train to alter birefringence after light passage
through or reflection by an anisotropic material; e.g., quartz wedge, mica
plate, gypsum plate, or Berek compensator. Syn:gips plate;
glimmer plate; compensator. CF:Berek compensator; gypsum plate.
A route constructed to enable plant, supplies, and vehicles to reach a
mine, quarry, or opencast pit. In remote and isolated regions, the
provision of an access road may be very costly. Nelson
See:xenolith; xenocryst.
A roller conveyor with a flexible latticed frame that permits variation in
length.
A vein formed by the repeated filling of a channelway and its reopening by
the development of fractures in the zone undergoing mineralization.
a. In coal mining, bodies of combustible gases that tend to collect in
higher parts of mine workings and at the edge of goaves and wastes. They
are found in cavities, at ripping lips, at other sheltered places
protected from the ventilating current, and at the higher sides of rise
faces. Mason
b. The concentration or gathering of oil or gas in some form of trap.
Commercial accumulation is a volume or quantity sufficient for profitable
exploitation. AGI
See:cumulate
a. A cylinder containing water or oil under pressure of a weighted piston
for hydraulic presses, hoists, winches, etc. It is between the pumps and
the presses, keeps a constant pressure on the system, and absorbs shocks.
b. A storage battery.
c. In oceanography, a spring of rubber or steel attached to a trawling
warp, to lessen any sudden strain due to the trawl catching. CTD
Any conveyor designed to permit accumulation of packages or objects.
Usually roller, live roller conveyor, roller slat conveyor, or belt
conveyor.
The degree of conformity with a standard, or the degree of perfection
attained in a measurement. Accuracy relates to the quality of a result,
and is distinguished from precision, which relates to the quality of the
operation by which the result is obtained. AGI
A trigonal mineral, CH3 CONH2 . Syn:acetic acid amine;
ethanamide.
See:acetamide
The most brilliant of illuminating gases, C2 H2 . It may be
produced synthetically from its elements, by incomplete combustion of coal
gas, and commercially from calcium carbide, CaC2 . It also may be
produced by reaction with water. Used in manufacturing explosives. Formerly used as an illuminating gas in mines and around drill rigs. When
combined with oxygen, acetylene burns to produce an intensely hot flame
and hence now is used principally in welding and metal-cutting flame
torches. Syn:ethyne; ethine. CF:gas
Standard, 2; Bennett; Long
See:carbide lamp
Yellowish liquid; CHBr2 CHBr2 ; sp gr, 2.98 to 3.00; boiling
point, 239 to 242 degrees C with decomposition (at 760 mm); also, boiling
point, 151 degrees C (at 54 mm); melting point, 0.1 degrees C; and
refractive index, 1.638. Used for separating minerals by specific gravity;
a solvent for fats, oils, and waxes; a fluid in liquid gases; and a
solvent in microscopy. CCD, 2