Dark lines in the solar spectrum resulting from absorption of light by
chemical elements in the chromosphere.
This water-sampling device is messenger actuated. It is designed to allow
free flow while in the cocked position on the downward traverse. When the
desired sampling point has been reached, the closures are messenger
actuated, resulting in isolation of the sample on the return traverse.
Frautschy bottles may be attached to the hydrographic wire at intervals
and in such a manner that release of a single messenger from the surface
will actuate the entire series. In this way samples from several depths
may be obtained in a single operation. Hunt
A hexagonal mineral, CoSe ; nickeline group; in trace amounts with
clausthalite, trogtalite, and hastite in dolomite veinlets in the Trogtal
quarries, Harz Mountains, Germany.
a. Native; uncombined with other elements, such as free gold or free
silver (native gold or native silver). Fay
b. Chemically uncombined or readily obtainable in uncombined form by
heating, as opposed to bound; e.g., free water or free oxygen.
Free acidity is considered to be the portion of the total acidity that
exists in the form of acid, both ionized and un-ionized. Felegy
a. Air under conditions of atmospheric pressure and temperature. The
condition of the air at the intake of the compressor, whatever the
temperature and barometric pressure may be. Lewis
b. The total area of open space in a grille through which air can pass.
Strock, 2
A gravity anomaly calculated from a theoretical model and elevation above
sea level, but without allowance for the attractive effect of topography
and isostatic compensation. See also:anomaly
a. See:free-air anomaly
b. A correction for the elevation of a gravity measurement, required
because the measurement was made at a different distance from the center
of the Earth than the datum. The first term of the free-air correction is
0.09406 mgal/ft (0.3086 mgal/m). AGI
a. A bituminous coal having so little fusibility that enough air for rapid
combustion can flow between the lumps and high enough in volatiles and
fixed carbon to burn readily. Hess
b. Coal that does not cake in the fuel bed and which has a high volatile
matter. BS, 4
Iron carbide in cast iron or steel other than that associated with ferrite
in pearlite. CTD
Eng. A variety of soft marly chalk; Sussex. Arkell
The circulation of a drilling fluid, the flow of which is not restricted
by obstructing materials in the borehole or inside the drill string.
Long
Crushing under conditions of speed and feed such that there is plenty of
room for the fine ore to drop away from the coarser part and thereby
escape further fine crushing. CF:choke crushing
The cyanide not combined in complex ions. ASM, 1
An adit. A level that drains through an adit.
See:free face
a. A longwall face with no props between the conveyor and the coal.
See also:prop-free front
b. A surface in the vicinity of a shothole at which the rock is free to
move under the force of the explosion. BS, 12
c. The exposed surface of a mass of rock, or of coal. Also called free
end. Zern
a. An arrangement by which, in deep boring, the bit is allowed to fall
freely to the bottom at each drop or downstroke.
b. The process of operating the drill. Often called Russian, Canadian, or
Galician free fall.
In ball milling, the peripheral speed at which part of the crop load
breaks clear on the ascending side, and falls clear to the toe of the
charge. Pryor, 3
A sliding piece in percussive boring designed to reduce the vibration and
jarring effects when the downward movement of the chisel is suddenly
arrested by striking the bottom of the borehole. The lower portion (which
is attached to the chisel) is free to slide up and down in a slot provided
in the upper part of the joint. When the chisel strikes the bottom of the
hole, the slot allows the rods to continue the downward movement without
being jarred by the blow of the chisel. See also:jar
In comminution, rolls are said to be free fed when fed only enough
material to keep a ribbon of ore between the rolls. This results in a
remarkably uniform product. CF:choke fed