A type of nigritite that occurs in sediments. CF:polynigritite;
keronigritite. AGI
An organic mud composed of humic material corresponding in rank to
sapropel. Tomkeieff
A microscopical constituent of torbanite; translucent; dark brownish-red;
isotropic. See also:gelosite; matrosite; retinosite. Tomkeieff
See:booster conveyor
A concentrating device that exploits differential densities of coal and
its associated impurities by a combination of sluicing and centrifugal
action. The material gravitates down through a stationary spiral trough
with six turns (five for ore treatment) of mean radius 8 in (20.32 cm)
with a fall per turn of 11 in (27.94 cm). Heavy particles stay on the
inside, the lightest ones climb to the outside, and the resulting bands
are separated at convenient points.
Dark-colored, organic, well-decomposed soil material consisting of the
residues of plant and animal materials together with synthesized cell
substances of soil organisms and various inorganic elements.
Stokes
a. Coal composed of anthraxylon in varying proportions and of varying
thicknesses, associated with transparent attritus. AGI
b. Amorphous brown to black coal formed from vegetable matter and
insoluble under continuous boiling in caustic alkalies; also insoluble in
water and benzol. Hess
A weight commonly reckoned in the United States, and for many articles in
England, at 100 avoirdupois lb, but commonly in England, and formerly in
the United States, at 112 avoirdupois lb. There is also an older
hundredweight, called the long hundredweight, of 120 avoirdupois lb.
Abbrev., cwt. Standard, 2
An inferior greenish cat's eye obtained in the Fichtelgebirge in Bavaria.
No such stone occurs in Hungary. CMD
A rotating, grinding mill used in Hungary for removing small portions of
gold from quartz by mixing with mercury; one of the many forms of pan
amalgamators.
a. A white opal, with a fine color play; found in Slovakia.
b. A name used by the importing trade for any white opal regardless of
origin.
Riffles used in undercurrents that are small angle irons or pieces of wood
shod with iron. Syn:transverse riffles
Delay in a blasting explosion caused by dampness of the powder or by too
slow combustion of the fuse. Korson
a. Said of a rock, lode, or belt of country that is barren of ore minerals
or of geologic indications of ore, or that contains very low-grade ore.
Ant: likely. AGI
b. Said of a soil that is poor or not fertile. AGI
a. A shot that does not explode immediately upon detonation or ignition.
See also:hangfire
b. A delayed shot. Hudson
Consists of roasting matte carrying copper, lead, gold, and silver at a
very low temperature, forming copper sulfate and oxide, but not silver
sulfate. This product is leached with dilute sulfuric acid for copper. The
resulting solution is treated with calcium chloride, and the copper is
precipitated as subchloride by passing SO2 through the solution.
The cuprous chloride is then reduced to cuprous oxide by milk of lime,
regenerating calcium chloride, and the cuprous oxide is smelted.
Liddell
A silver arsenide occurring with native silver at Silver Islet, Lake
Superior, MI. Fay
a. Unstable conditions occur with all fans when they are working against
too high a resistance, and with forward-bladed radial-flow fans over most
of their range, including the point of maximum efficiency. In these
conditions, a drop in volume causes only a slight rise in fan pressure and
conditions are only slowly restored to normal. This leads to continual and
heavy fluctuations in load, a phenomenon known as "hunting." In extreme
cases, a fan may hunt to the point where there is no rise in pressure with
decreasing volume. It can then lose its load entirely and never recover
it. Roberts, 1
b. Abnormal time lag in automatic control system, in which a corrective
change is so much exceeded that overmodulation ensues, the result being
oscillation above and below the desired norm. Also called cycling;
oscillation. Pryor, 3
York. Ribs and posts of coal left for second working. Fay
A sink-float process employing a galena medium and utilizing froth
flotation as the means of medium recovery. Chem. Eng.
A cylindrical vertical tub from 3-1/2 to 6 ft (1.07 to 1.83 m) in
diameter, with screen-guarded peripheral apertures through which ore pulp
can be discharged after passing through the comminuting zone. Grinding is
done by four rolling mullers, which hang inside from a yoke and which
press outward when rotating, thus bearing an ore caught between them and
the inner wall of the tub. Syn:pendulum mill