Congos used industrially as bort. See also:bort
See:congos
Spherical- or near-spherical-shaped congos. See also:congos
Long
a. Originally and commonly used as a name for a variety of diamonds found
in the Republic of the Congo diamond district in Africa and more recently
as a descriptive term applied to all diamonds having the appearance and
characteristics of those produced in the Republic of the Congo. Congos are
white to gray-green and yellow, drusy-surfaced, opaque to somewhat
translucent diamonds, having shapes corresponding to the many forms
characteristic of the isometric (cubic) crystal system. At one time,
congos were considered fit only for use in fragmented form, but a
considerable number are now used as tool stone and drill diamonds.
Syn:congo diamond
b. Sometimes designates drill diamonds ranging from one to eight stones
per carat in size. Long
a. In crystallography, any motif that may generate another by rotation or
translation, but with no change in chirality.
b. In phase equilibria, the melting of a crystalline compound to a liquid
of the same composition. CF:incongruent melting
In crystallography, two forms that may each be derived from the other by
rotation about an axis of symmetry. Fay
A geologic or metallurgical process in which a binary compound melts at a
certain concentration to a liquid of its own composition.
CF:incongruent melting
Cone-shaped. In mineralogy, usually an elongated cone as are most icicles.
A winding drum, cone-shaped at each end, for balancing the load upon the
engine during winding operations. See also:winding drum
loaded upgoing rope winds on the small diameter while the lightly loaded
downgoing rope winds off the large diameter of the cone. Nelson
Gyratory-type crusher used for secondary reduction and identified by the
shape of its breaking head. The large included angle of the breaking-head
surfaces greatly increases the ratio of discharge to feed area; a large
ratio permits crushed materials to separate to prevent power-consuming
clogging and packing. The crusher's higher gyrating speed and large
discharge area make it eminently suitable for fine crushing at a high
capacity. Pit and Quarry
See:Hardinge mill
The refraction of a ray of light at certain points of double-refracting
crystals, so that on emerging from the crystal it widens from an apex into
a hollow cone (external conical refraction), or on entering diverges into
a cone and issues as a hollow cylinder (internal conical refraction).
Standard, 2
An orthorhombic mineral, CaCu(AsO4 )(OH) ; adelite group; forms
series with austinite, with calciovolborthite, and with cobaltoaustinite;
formerly called higginsite.
Method of obtaining true sample from a pile of ore by forming a cone with
the material flattening the cone, and removing shovelfuls successively
onto four separate heaps of which two are rejected. If there is sufficient
material the two opposite quadrants are rejected and the remaining two are
combined, reconed, and requartered. As the process is repeated and the
pile shrinks, it must be crushed to a smaller size to permit accurate
blending of the various sized particles during mixing. Syn:upconing;
quartering. Pryor, 3
A method of sample reduction. Syn:quartering
Two sets of related veins that dip in different directions.
A system of two intersecting sets of parallel faults.
Two impedances having resistive components that are equal and reactive
components that are equal in magnitude but opposite in sign are known as
conjugate impedances. Hunt
Sets of intersecting joints that are sometimes perpendicular or
rectilinear, and often mineralized to form vein systems. Joint patterns
such as these are believed to be the result of compressive stresses that
were relieved by joint formation rather than the formation of a single
fissure. Lewis
A conveying belt that passes under magnets, below which belts run at right
angles to the line of travel of the main belt. The magnetic particles
(tramp iron) are lifted up against these crossbelts and are thus removed.
Liddell
A dense-media coal cleaning process in which the separating medium
consists of minus 200-mesh magnetite (sp gr, 5.2) in water in the desired
proportions (4.4 parts of water to 1 part of magnetite provides an
effective specific gravity of about 1.9). This process has the advantage
that the medium requires little agitation to keep it in suspension and is
easily removed from the clean coal and refuse. Mitchell