An apparatus having a shaking, oscillatory, or rotary motion, used for
screening or sifting coal, stamped ores, and the like.
a. Fine coal that will pass through the smallest mesh screen normally
loaded for commercial sale for industrial use. BCI
b. The residue from a screening operation. Nelson
A stage in bituminous coal crushing in which units for crushing screenings
reduce secondary product to final small, commercial sizes, such as 1- to
3/8-in (2.5- to 1-cm) stoker coal or screenings. Mitchell
Accumulation of surface debris on the lower slopes of iron-bearing hills.
The scree material may contain sufficient iron ore to make its mining an
economic proposition as at Middleback Ranges of South Australia.
Nelson
A type of chute with a bar screen or grizzly bottom that permits fines to
fall onto the conveyor belt first, providing a cushion for the large
material that passes over the screen.
That portion of the feed material discharged from the screen deck without
having passed through the apertures. BS, 5
A perforated pipe lined with fine-mesh screen, set in portions of a
borehole where the walls must be supported and the ingress of water or oil
cannot be restricted. Also called well point. Long
a. A metal plate with specific-sized openings used to control the fineness
of grinding in dry pans and hammer mills. ACSG, 2
b. A plate provided with apertures of specified size for use as a screen
deck. BS, 5
That part of a breaker where boys picked slate and bony. Korson
Wire meshes with specific-sized openings for grading particles of various
sizes. See also:vibrating screen
A standard for determining the size of particles. The particles are passed
through screens with openings of specified size. The size of the particles
is determined by the size of the opening through which the particles will
not pass. Long
Separating various-sized grain into portions, by a screen or sieve. Also
called screening; sizing.
That portion of the feed material that has passed through the apertures in
a screen deck. BS, 5
Scot. An iron plate at the foot of a screen on which screened coal is
discharged.
a. The feed screw in the swivel head of a gear-feed diamond drill.
Long
b. Syn. for an auger stem having helical webs. Long
c. A combined symmetry operation involving rotation about an axis and a
translation parallel to it. CF:space group
d. A crystal defect involving a dislocation about which layers of adatoms
spiral during crystal growth. CF:Burgers vector
a. A device to withdraw broken rods from a borehole, when the fracture
occurs below a joint. The screw bell is lowered to cut a thread on the end
of the broken rod and thus secure a grip sufficient to withdraw it safely.
Nelson
b. A fishing tool shaped like a bell, bell tap, or bell screw.
Long
c. See:bell screw; bell socket; bell tap.
a. A conveyor screw revolving in a suitably shaped stationary trough, or
casing fitted with hangers, trough ends, and other auxiliary accessories.
b. A conveyor in which a spiral blade presses material forward as it
rotates in a suitable housing. Syn:tubular screw conveyor;
spiral conveyor. See also:grit collector; vertical screw conveyor.
Pryor, 3
That mechanism on a mill for lowering and raising the rolls to accommodate
the distance between them to the requirements of the article being rolled.
Mersereau, 2
Vertical screw elevators are used for handling pulverulent materials. A
typical installation for delivering bulk cement into a plant consists of a
screw feeder, which takes the cement from the bulk-cement car and feeds it
to the screw elevator. Both these units are airtight and all joints are
fitted with rubber gaskets that prevent the loss of cement and render the
operation dustproof. Pit and Quarry
See:axial-flow fan
A system of gears, ratchets, and friction devices, or some combination of
these parts, in the swivel head of a diamond drill, which controls the
rate at which a bit is made to penetrate the rock formation being drilled.
When controlled by a feed gear, the bit maintains the same penetration
rate per revolution regardless of drill-stem revolutions per minute. Also
called gear feed, mechanical feed. Long