A machine that combines coal crushing and screening. It consists of a
revolving cylindrical screen 8 to 14 ft (2.4 to 4.3 m) in diameter and 13
to 22 ft (4.0 to 6.7 m) in length. It breaks the coal by gravity impact.
On reaching the desired size, the coal is discharged through the plates.
It can deal with run-of-mine coal up to 12 in (30.5 cm) at a rate of 500
to 600 st/h (454 to 544 t/h), to give a product size of below 1-1/2 in
(3.8 cm); other sizes can be produced, depending on the screen plates
used. See also:screen
A monoclinic mineral, Na3 Mg(PO4 )(CO3 ) ; in
veryfine grains in saline oil shale in Wyoming.
A long-continued, extremely slow vertical instability of the crust, as in
the volcanic district west of Naples, Italy, where the Phlegraean
bradyseism has involved up-and-down movements between 6 m below sea level
and 6 m above over more than 2,000 yr (Casertano). Etymol: Greek "bradys"
(slow) + "seismos" (earthquake). AGI
Insufficiently charred wood, as in charcoal burning. Standard, 2
The angle, theta , at which X-rays diffract in crystalline materials. It
satisfies the relationship n lambda = 2 d sin theta , where d is the
distance between diffraction planes of atomic particles in a crystal
structure, lambda is the wavelength of the X-rays, and n is the order of
diffraction when a crystal is placed in an X-ray beam.
The index numbers assigned to a diffracted X-ray beam. They have the same
values as Miller indices but are written without closures. Diffraction
order may be factored into Bragg indices, e.g., 111, 222, 333... represent
n = 1, 2, 3... for diffraction from atomic planes parallel to 111 .
CF:Miller indices
A tetragonal mineral (Pt,Pd,Ni)S : steel gray, minute grains in
concentrates from the Bushveld norite of the Transvaal, South Africa. A
source of platinum and palladium.
A stream that divides into an interlacing or tangled network of several
small branching and reuniting shallow channels separated from each other
by branch islands or channel bars, resembling in plan the strands of a
complex braid. Such an anastomosing stream is generally believed to
indicate an inability to carry all of its load, such as an overloaded and
aggrading stream flowing in a wide channel on a flood plain. AGI
a. A device (as a block or band applied to the rim of a wheel) to arrest
the motion of a vehicle, a machine, or other mechanism and usually
employing some form of friction. Webster 3rd
b. A device, either hand- or power-operated, for applying resistance to
the drum or pulley and thus controlling the movement of mine cars or
cages. A common form is a brakeshoe, lined with friction material, which
is applied to the surface of a wheel or drum, and thus retards or even
stops its movement. See also:winder brake
Nelson
c. Eng. A stout, wooden lever to which boring rods are attached. It is
worked by one or more people.
d. N. Staff. To lower trams on dips by means of a wheel and rope.
A rotating cylinder with a machined inner or outer surface upon which a
brake band or brakeshoe presses. Nichols, 1
a. An incline in which the full trucks descend by gravity and pull up the
empty ones. See also:gravity haulage
b. Gravity plane. Pryor, 3
a. Person who attends to a brake or brakes, as on a railroad car.
Standard, 2
b. Eng. The person in charge of a winding (hoisting) engine for a mine.
"Brakeman" is usually used in the United States; "brakesman" is the
British usage. The person in charge of hoisting engines, esp. in the
United States, is usually called a hoisting engineer. Fay
c. In mining, a laborer who rides on trains or trips of cars hauled by
locomotive or hoisting cable or chain, and assists in their transportation
to surface or shaft bottom for hoisting; operates or throws switches;
couples and uncouples cars, or attaches and detaches cars to and from the
cable; opens and closes ventilation doors in mines; directs movement of
the train by signaling motorman. May be designated according to type of
hauling machine, such as dinkey operator helper. Also called brake holder,
car rider, conductor, dukey rider, gang rider, motorman helper, nipper,
patcher, rider, rope conductor, rope rider, set rider, snapper, tailend
rider, trailer, train conductor, trainman, transfer car helper, trip
rider, tub rider. Syn:conductor
A jigger operated by a hand lever. Fay
a. A hand wheel for operating a brake, as on a vehicle.
Webster 2nd
b. A wheel or pulley on which a friction brake acts. Webster 2nd
c. A heavy wheel provided with cams for controlling the movement of a
triphammer. Webster 2nd
Tbe distance the haulage unit (i.e., train) will travel after the
application of the brakes, depending on the speed, the weight of
locomotive and train, and the gradient. Sinclair, 5
A micaceous mineral differing from illite because it contains soda in
excess of potash. Found in crevices in coal measure shales from Llandebie,
South Wales. Syn:sodium illite
See:brasses
a. An underground road or heading driven in coal measures; also, a roadway
turned from a level, etc. Syn:branch hole
b. A small vein departing from the main lode. CF:main hole
A minor fault that branches from a larger fault. Stokes
Headings that are turned off the main level at intervals for development
purposes. They may proceed to the rise or dip and are adopted in longwall
and pillar methods of working. See also:opening out
See:branch