a. In the dense-media separation process, fluid media partly composed of a
mineral species selected from material being treated. Pryor, 4
b. Selectively sized lumps of material used as grinding media.
Pryor, 4
The secondary grinding of coal or ore by tumbling in a revolving cylinder
with no balls or bars taking part in the operation. Nelson
Roasting in which the heat generated by oxidation of the sulfides is
sufficient to propagate the reaction. Newton, 2
The development of new minerals in an igneous rock by the action of its
own magmatic water on already existing magmatic minerals.
Schieferdecker
See:autointrusion
a. A process wherein the residual liquid of a differentiating magma is
injected into rifts formed in the crystallized fraction at a late stage by
deformation of unspecified origin. Syn:autoinjection
b. Sedimentary intrusion of rock material from one part of a bed or set of
beds in process of deposition into another part. AGI
a. An inclusion in an igneous rock to which it is genetically related.
CF:xenolith
b. In a granitoid rock, an accumulation of iron-magnesium minerals of
uncertain origin. It may appear as a round, oval, or elongate segregation
or clot. AGI
Analysis in which the coal sample passes first to a conditioning unit,
which dries and grinds it, then to an X-ray analysis unit. The analysis is
based on the difference in the reflection of X-rays by the combustible and
noncombustible components of the sample. The reflection is compared
photoelectrically with a reference sample. Nelson
A device used with certain types of belt conveyors for the taking up or
storage of belt during reversible operation. Jones, 1
An appliance for attaching and detaching mine trams or cars without manual
effort. It is generally attached at inby clipping stations and detached at
the shaft bottom. See also:clip; coupling; haulage clip. Nelson
A clutch whose engagement is controlled by centrifugal force, vacuum, or
other power without attention by the operator. Nichols, 1
A device that automatically couples cars when they bump together.
Zern
A system of automatic winding in which the complete installation operates
without human aid and winding continues automatically as long as coal is
available at the shaft bottom and is cleared at the bank.
Syn:cyclic winding
Ward-Leonard control; manual winding control; semiautomatic control.
Nelson
See:boomer
a. A mine door operated by pressure of the locomotive wheels on a switch
along the rails approaching the doors, which closes the door automatically
after the trip has passed. These doors are preferable to regular mine
doors. However, they must be carefully maintained to keep them in a safe
operating condition.
b. A wooden door arranged to close automatically when released, by
installing the door with a slight lean in the direction of closing.
Air doors on a haulage road that are automatically operated by a passing
vehicle or train of tubs, or other means. BS, 8
a. A hydraulic-control system of valves that when once set and without the
manual assistance of a drill runner will reduce or increase feed pressure
applied to a drill stem as hardness of rock penetrated changes.
Long
b. A pneumatic rock drill equipped with a power-actuated feed mechanism.
Long
An automatic, timed sampling device used at mill feeds and other plants.
Nelson
automatic heat-treating machine
See:Gilman heat-treating machine
The starting and stopping of a pump by a mechanism actuated by the level
of water in the suction well or pump, or by the level or pressure of water
in a discharge tank. BS, 10
An arrangement to stop and start a mine pump automatically by means of a
float switch. Nelson