A cylindrical shell lined with grooved rubber set parallel to its axis,
which is inclined, peripheral riffles thus being formed. Used to arrest
heavy particles such as metallic gold as auriferous pulp flows gently
through while the cylinder revolves slowly and the arrested material rises
and drops on to a separate discharge launder. Pryor, 3
Modified form of Frue vanner. Pryor, 3
See:rinkite
a. A divisional plane or surface that divides a rock and along which there
has been no visible movement parallel to the plane or surface.
Ballard
b. A standard length of drill rod, casing, or pipe equipped with threaded
ends by which two or more pieces may be coupled together; also, two or
more standard lengths of drill rods or pipe coupled together and handled
as a single piece in round trips. Long
c. A fracture or parting that cuts through and abruptly interrupts the
physical continuity of a rock mass. Not to be confused with bedding or
cleavage. Long
d. A line of cleavage in a coal seam. Syn:heading seam
See also:joint plane
A cast iron box surrounding an electric cable joint, often filled with
insulation after the joint between cables has been made. Hammond
a. In quarrying, the process of cutting to specified sizes and shapes,
with smooth unchipped edges. AIME, 1
b. The condition or presence of joints in a body of rock. AGI
Insulating thimbles placed over the connected ends of detonator leads
coupled in large rounds of shots, and also over the connections between
the detonator leads and the shot-firing cable. BS, 12
A visible line on imperfect glassware reproducing the line between
separate parts of the mold in which the glass was made. Also called
parting line; match mark; miter seam; mold mark; mold seam. Syn:seam
Dodd
A plane along a joint fracture or parting. Not to be confused with bedding
and/or cleavage. See also:joint
A rose diagram that shows the azimuth and intensity of jointing in an
area.
Natural cracks or fractures in rocks. They tend to occur in more or less
parallel systems, and when quarry walls are maintained parallel and at
right angles to them, they may be utilized as natural partings in the
process of block removal. AIME, 1
A group of more or less parallel joints. Billings
Consists of two or more joint sets or any group of joints with a
characteristic pattern, such as a radiating pattern and a concentric
pattern. Billings
Full of joints; specif. in mining, full of minute cracks or crevices, as
rock. Standard, 2
a. A spring balance used to measure specific gravity of mineral specimens
by weighing a specimen both in the air and immersed in a liquid of known
density. McGraw-Hill, 1
b. A spiral-spring balance with two specimen pans, one for measuring
weight in air and one for weight in water, used to determine specific
gravity. CF:Westphal balance
A hardenability test in which a standard test piece, 4 in (10.2 cm) long
and 1 in (2.54 cm) in diameter, is heated to a predetermined temperature,
rapidly transferred to a jig fixture, and quenched, under standard
conditions, by a jet of water impinging at one end. When the specimen is
cool, determinations of hardness are made along it from the quenched end.
The diagram relating hardness to distance from the quenched end of the
specimen is known as a hardenability curve. Hammond
An apparatus used for cutting the size of a sample. It consists of a
hopper above a series of open-bottom pockets, usually 1/2 in or 3/4 in
(1.27 cm or 1.91 cm) wide, which are so constructed as to discharge
alternately, first into a pan to the right, and then into another pan to
the left. Each time the sample is passed through the riffle, it is divided
into two equal parts; the next pass of one of those parts will give a
quarter of the original sample, and so on, until the sample is reduced to
the desired weight. Pearl
A device used to reduce the volume of a sample consisting of a belled,
rectangular container, the bottom of which is fitted with a series of
narrow slots or alternating chutes designed to cast material in equal
quantities to opposite sides of the device. Also called sample splitter.
CF:riffle
Method of soil consolidation used in tunneling through sands and gravels.
Solutions of calcium chloride and sodium silicate are forced into the
ground, where they mingle and produce a watertight gel. Pryor, 3
A device used for jigging the shaker products of the diamond washer. The
products are fed to the jigs, one at a time, and jigged, with frequent
stoppages for scraping off the top layer of tailings; more sand is added,
and the process is repeated until a product is obtained that consists
entirely of concentrates. Griffith
A monoclinic mineral, Pb14 (As,Sb)6 S23 ;
pseudohexagonal; forms a series with geochronite in which antimony
increases relative to arsenic.