An attachment to a surveyor's transit with which an angle of inclination
is measured in terms of the tangent of the angle instead of in degrees and
minutes. It may be used as a telemeter in observing horizontal distances.
AGI
The gradient at which the tractive force required to pull an empty tram
inby (slightly uphill) is equal to that required to pull a loaded tram
outby. This was formerly termed horse haulage gradient. In general,
haulage roads are graded about 0.5% in favor of the loaded trams.
Nelson
a. The relative proportions of the variously sized particles in a batch,
or the process of screening and mixing to produce a batch with particle
sizes correctly proportioned.
b. The commercial operation of sorting coke between two screens such that
the ratio of the larger to the smaller screen aperture does not exceed 2.5
to 1; the coke which has been so sorted. BS, 3
c. The gradual reduction, upward in a sedimentary bed, of the upper
particle-size limit. It implies pulsatory turbulent-fluid deposition.
CF:graded bedding
See:screen analysis
A balance-type gravity meter that is heavily damped in order to attenuate
shipboard vertical accelerations. It consists of a mass at the end of a
horizontal arm, supported by a torsion-spring rotational axis. The mass
rises and falls with gravity variation, but is restored to near its null
position by a horizontal reading spring, tensioned with a micrometer
screw. The difference between actual beam position and null position gives
indication of gravity value after the micrometer screw position has been
taken into account. See also:gravimeter
Graham pressure surveying apparatus
A barometric surveying instrument that is free from the many defects of
the aneroid barometer. The apparatus records the change in pressure of a
constant volume of air maintained at a constant temperature.
The ratio of the amount of carbon monoxide produced over the oxygen
absorbed varies with the temperature of oxidation of coal and also with
the time of coal exposure to oxidation, thereby allowing this ratio to be
used as an index of the rate of oxidation in a mine. Roberts, 1
Gravel or sand; anything in fine particles. Standard, 2
a. A mineral or rock particle having a diameter of less than a few
millimeters and generally lacking well-developed crystal faces; e.g., a
sand grain. Also, a general term for sedimentary particles of all sizes
(from clay to boulders), as used in the expressions grain size,
fine-grained, and coarse-grained. AGI
b. A quarrymen's term for a plane of parting in slate that is
perpendicular to the flow cleavage; or for a direction of parting in
massive rock, e.g., granite, that is less pronounced than the rift and
usually at right angles to it. CF:rift
c. The second direction of easy splitting of a rock, less pronounced than
the rift, but more so than the hardway.
d. A unit of hardness of water, expressed in terms of equivalent CaCO (sub
3) . A hardness of 1 grain per U.S. gal (17.1 mg/L) equals 17.1 ppm by
weight as CaCO3 . See also:anthracite fines
An interface between two crystals putting all adjacent ions in an
irregular crystalline environment. CF:lineage
Grainer salt screened to give a mixture of coarse- and medium-size flakes,
excluding very coarse and very fine flakes. Kaufmann
Diamonds which in weight will correspond to fourths of a carat; a diamond
weighing one-half carat is a two-grainer; one weighing three quarters is a
three-grainer; a diamond of one carat in weight is a four-grainer.
Hess
Salt produced by the grainer process of surface evaporation from brine.
Product has a characteristic flaky shape consisting of hoppers and hopper
fragments. Kaufmann
Movement between individual mineral grains.
Gold that has become granular in the process of heating. Fay
The growth of a crystal, as from solution on the walls of a geode, in open
pore space, or in a magma chamber; crystal growth. AGI
a. A term relating to the size of mineral particles that make up a rock or
sediment. See also:particle size
b. For metals, a measure of the size of grains in a polycrystalline
material, usually expressed as an average when the individual sizes are
fairly uniform. Grain sizes are reported in terms of number of grains per
unit area or volume, as average diameter, or as a grain-size number
derived from area measurements. ASM, 1
c. The size or size distribution of refractory particles, which is usually
determined by sieve analysis. ARI
A scheme of rock classification based upon the average size of certain
chosen components; thus, each clan comprises coarse-, medium-, and
fine-grained members. CTD
a. The granular or nodular form of cassiterite, tin oxide, SnO2 ;
also known as stream tin. Henderson
b. Metallic tin of high grade obtained by charcoal reduction.
Henderson
A set of tools, picks, shovels, wedges, hammers, etc., used for work
underground. CTD
The atomic weight of an element expressed in grams. Hackh