As a result of high-speed, excessive pressure, and poor water circulation,
sufficient heat may be generated at the bottom of a borehole to cause a
diamond crown to soften, resulting in displacement of diamonds and a
ruined bit. Nelson
A cut made in the face of a heading for which three or four holes are
drilled normal to the face and in a triangle or square, 12 to 18 in (30.48
to 45.72 cm) on a side, with another hole in the center. One, two, or
three holes are loaded and shot; the others relieve the pressure and
induce breaking. A cavity is formed to which other shots in the face
readily break. Used for esp. tough ground. Also called Michigan cut;
woodchuck cut. Hess
Calcium oxide (quicklime) formed from limestone, or other forms of calcium
carbonate, which has been calcined at high temperature to drive off the
carbon dioxide. See also:burnt lime
a. To run a bit with too little coolant until the heat generated by the
bit fuses the cuttings, core, bit, and the bottom of the borehole.
Long
b. To deliberately run a bit with reduced amount of coolant until the core
is jammed inside the bit. Long
A furnace in which sulfide ores are calcined to form gaseous SO2
and leave the metal oxide, or in the case of noble metals, the metal
itself.
A common name for kerosine.
A loose term, usually used to describe the wearing away of furnace linings
without a known reason.
A laborer who gets ore ready for a mechanical shovel or a hand shoveler.
Hess
A situation encountered in coal seams, usually near the outcrop, where the
coal has undergone combustion and burned. Initiation sources could include
lightning, forest fires, etc.
To salvage diamonds from a used bit by dissolving the matrix alloy with an
acid or by use of an electrolytic process. Long
This machine has been specially developed for boring in all types of
ground, and incorporates a very important feature, that of controlling the
water immediately if it is tapped. In boring, the hole is first prepared
for the reception of a special rubber ring, two iron plates, and two
wedges. When these are properly adjusted, the rubber washer is compressed
and powerfully gripped on the sides of the borehole to effect a sound and
reliable joint. If during boring operations water should rush out and the
bore rods cannot be withdrawn, the two handwheels are screwed in; this
presses india-rubber plugs onto the bore rods and effects a watertight
joint. Mason
Alum that has been dried at 200 degrees C, and powdered; AINH4 (SO
4 )2 or AIK(SO4 )2 . A caustic.
Syn:dried alum; exsiccated alum.
a. Iron which by long exposure to heat has suffered a change of structure
and become brittle. It can be restored by careful forging at welding heat.
Fay
b. In the Bessemer and open-hearth processes, iron that has been exposed
to oxidation until all of its carbon is gone, and an oxide of iron has
been formed in the mass. Fay
Calcitic lime, CaO, or dolomitic lime, CaO.MgO. See also:burned lime
Metal that has become oxidized by overheating, and so is rendered useless
for engineering purposes. CTD
a. An antique carnelian, such as is sometimes found in ancient ruins and
has apparently been acted on by fire. Fay
b. A gemstone with color changed by heating; e.g., amethyst, which changes
from purple to clear; or tiger-eye, which changes from yellowish-brown to
reddish brown. Syn:heat-treated stone
See also:heated stone
a. A term used in England for a rough or hard stone, such as a compact
siliceous sandstone esp. hard to drill. Also spelled bur. AGI
b. A knob, boss, nodule, or other hard mass of siliceous rock in a softer
rock; a hard lump of ore in a softer vein. AGI
c. See:buhrstone
An aggregate of muscovite books and quartz. Skow
See:buhrstone
An explosive breaking of coal or rock in a mine due to pressure. In coal
mines bursts may or may not be accompanied by a copious discharge of
methane, carbon dioxide, or coal dust. Also called outburst; bounce; bump.
See also:rock burst
a. A hydraulic mechanism that, when inserted into a large-diameter
shothole, breaks down the strata by means of pistons operating
transversely. BS, 12
b. Scot. A shot in a coal seam that has not been sheared or undercut.
Equivalent to "shot off the solid." Also called bursting shot.