A bit, the crown of which is formed by applying heat and pressure to a
mixture of powdered metals covering diamonds set inside a mold or
die-shaped to the form of a bit crown. The bit crown thus formed may be a
surface-set, multilayer, or impregnated type. Long
A zone of sinter typically positioned at the top of epithermal systems.
Sintering as used in powder metallurgy consists of mixing metal carbide
powders having different melting points, and then heating the mixture to a
temperature approximating the lowest melting point of any metal included.
In sintered carbides, powdered cobalt, having the lowest melting point,
acts as the binder, holding together the unmelted particles of the hard
carbides. See also:cemented carbide
The pick generally used in coal cutters and cutter loaders, in which the
sintered tip is brazed in various ways to the shank of the pick. In the
external-tip type, which is widely used, the sintered tip is brazed
externally to the shank, which is usually a forging. It is self-gaging and
as the tip wears down, the cutting edge maintains its shape and clearance.
In the slotted type, the tip is brazed into a slot cut in the shank of the
pick. In the inserted-rod type, the sintered carbide takes the form of a
rod inserted into a hollow in the shank of the pick, which is a forging.
These picks are widely used in the soft coal mines in Germany.
See also:tungsten carbide bit; coal-cutter pick.
Syn:inserted rod-type pick
A bit-crown diamond-embedment metal or alloy produced by a sinter
powder-metal process. See also:sinter; sinter bit. Long
See:sinter bit
A heat treatment for agglomerating small particles to form larger
particles, cakes, or masses; in case of ores and concentrates, it is
accomplished by fusion of certain constituents. CTD
A plant in which sintering is carried out. Nelson
See:sinter bit
See:sinter bit
See:turbulent flow
A decorative brown jasperlike, fine-grained quartz, from Sioux Falls, SD.
Used for tables and interior architectural trim.
An arrangement of closed pipes and valves to conduct water from one level
to a lower level over an intervening ridge. The difference of level
between the inlet and outlet ends of the pipe column must be sufficient to
provide a head great enough to overcome the frictional resistance of the
pipe column. The siphon was often used in the earlier days of mining when
pumps were too costly or power was not available. See also:suction head;
inverted siphon. Nelson
The action or operation of a siphon. Fay
An apparatus for the sizing of pulverized ores in an upward current of
water. Fay
See:Arents tap
See:typrite
A centrifugal fan, invented by Samuel Davidson in 1898, with 64 narrow
blades curved forward, mounted at the periphery of a braced, open drum. It
is a high-speed, small-diameter fan, usually direct driven. It was a
popular fan in Great Britain for many years. See also:Waddle fan
Nelson
Former name for iridosmine.
Former name for Mg-rich chloritoid.
a. The investigation and testing of the surface, subsoil, and any
obstruction at a site to obtain the full information necessary for
designing a complete structure with its foundations. Hammond
b. See:site investigation