See:error curve
a. The Tromp process was the first to introduce (about 1938) the use of
magnetite suspension in dense-medium washing. The magnetite is ground to
about minus 1/250 in (0.1 mm) and added to water. The process makes use of
an unstable suspension with horizontal currents of differing densities at
intermediate levels. The process operates within the size range 6 to 200
mm and in practice is used for raw coal down to 1/4 in (6.4 mm). It gives
a reasonably accurate three-product separation. Nelson
b. A dense-medium process that utilizes a rapidly settling suspension of
finely powdered magnetite or sintered roasted pyrite. This process may be
used on any size of coal from 10 to 1/4 in (254 to 6.4 mm) and for any
specific gravity from 1.3 to 1.9. The grain size of the magnetite or
pyrite is minus 0.1 mm. The quick settling of the magnetite particles
gives a higher specific gravity in the lower layers of the wash box, which
makes it possible to obtain three products: clean coal, middlings, and
refuse. Mitchell
A monoclinic mineral, Na3 (Co3 ) ((HCO3 )X2H2
O ; soft; vitreous; colorless to white; alkaline tasting; in saline lake
deposits and desert soils; a major source of sodium compounds from
extensive deposits at Searles and Owens Lakes, CA, and in Wyoming,
Hungary, Egypt, Africa, and Venezuela. See also:sodium sesquicarbonate
The method used for the separation and the purification of soda ash
(anhydrous sodium carbonate), anhydrous sodium sulfate, boric acid, borax,
potassium sulfate, bromine, and potassium chloride from brine at Searles
Lake, San Bernardino County, CA. CCD, 2
A light-colored plutonic rock composed primarily of sodic plagioclase
(esp. oligoclase), quartz, sparse biotite, and little or no alkali
feldspar. Its name, given by Goldschmidt in 1916, is derived from
Trondhjem, Norway. Also spelled: trondjemite; trondheimite. AGI
See:trondhjemite
a. A manganoan variety of willemite occurring in large reddish crystals.
b. A previously unresolvable, rapidly etching, fine aggregate of carbide
and ferrite produced either by tempering martensite at a low temperature
or by quenching a steel at a rate slower than the critical cooling rate.
Preferred terminology for the first product is tempered martensite; for
the latter, fine pearlite. ASM, 1
Fine aggregates of ferrite and cementite in steel; emulsified ferrite.
Pryor, 3
Trade name of a single-shot borehole surveying instrument combining a
compass and inclinometer, which is locked in place by the action of a
preset time clock. Long
A special type of packing to protect explosives from deteriorating when
subjected to hot, humid atmospheric conditions, such as in tropical areas.
The explosives, after being sealed with paraffin, are packed in cartons,
which are then wrapped in waxed paper and also sealed with paraffin. The
filled cartons are then placed inside a satchel-type case liner of
bitumen-laminated paper reinforced with sisal fiber and completely sealed
with a waterproof adhesive. Nelson
a. A channel, open or covered, that contains coal or ore being conveyed on
a chain or shaker conveyor. The shape of the cross section depends on the
type of conveyor involved. See also:tray
b. A hollow or undulation in a mineral field, or in a mineral working. In
geology, synonymous with basin; synclinal. See also:graben
c. The lowest point of a given stratum in any profile through a fold.
CF:trough line
d. A line occupying the lowest part of a fold; the line connecting the
lowest parts on the same bed in an infinite number of cross sections.
See also:trough plane
Rhythmic layering or alignment of minerals in an igneous rock, confined to
troughlike depressions and considered to have been produced by currents
set up in the magma during cooling. AGI
A pan conveyor or gravity conveyor. Nelson
A belt conveyor in which the carrying side is made to form a shallow
trough by means of troughing idlers. Nelson
A belt conveyor with the belt edges elevated on the carrying run to form a
trough by conforming to the shape of the troughed carrying idlers or other
supporting surface. See also:belt conveyor
A roller conveyor having two rows of rolls set at an angle to form a
trough over which objects are conveyed. See also:el conveyor
A fault, generally a normal fault, that bounds a graben or other
structural depression. AGI
a. A structural section shaped like a wide U; riveted or welded to form a
bridge deck with the U-shaped sections turned alternately upwards and
downwards. Hammond
b. Making repeated dozer pushes in one track, so that ridges of spilled
material hold dirt in front of the blade. Nichols, 1
c. Eng. In Derbyshire, toadstones filling fissures.
A belt idler having two or more rolls arranged to turn up the edges of the
belt so as to form the belt into a trough. NEMA, 1
The rolls of a troughing idler that are so mounted on an incline as to
elevate each edge of the belt to form a trough. NEMA, 1
a. The line occupying the lowest part of the fold, or, more precisely, the
line connecting the lowest parts of the same bed in an infinite number of
cross sections. CF:trough
b. The line joining the trough points of a given stratum. AGI