The portion of an aggregate retained on the No. 4 sieve, consisting of
particles with diameters greater than 4.76 mm. CF:aggregate;
fine aggregate. AGI

Gold in large grains, as distinguished from gold dust. Also called coarse
quartz gold.

coarse-grained

Applied to rocks composed of large grains; used mainly in a relative
sense, but an average size greater than 5 mm in diameter has been
suggested. CF:medium-grained; fine-grained. Stokes

coarse-grained soil

A soil in which gravel and sand predominate. Coarse-grained soils are
those least affected by moisture-content changes as most surface rain,
etc., becomes gravitational water. Nelson

coarse jig

A jig used to handle the larger sizes and heavier grades of ore or metal.
Weed, 2

coarse metal

An iron-and-copper matte containing sulfur; a product of copper smelting
in a reverberatory furnace. Standard, 2

coarse roll

A large roll for the preliminary crushing of large pieces of ore, rock, or
coal. Used in stage crushing.

coarse sand

a. A geologic term for a sand particle having a diameter in the range of
0.5 to 1 mm (1 to 0 phi units). Also, a loose aggregate of sand consisting
of coarse sand particles. See also:sand
b. An engineering term for a sand particle having a diameter in the range
of 2 mm (retained on U.S. standard sieve No. 10) to 4.76 mm (passing U.S.
standard sieve No. 4). AGI

coaxial cable

Electrical cable with inner conducting wire covered by alternating layers
of insulating and conducting material. Pryor, 3

cob

a. Corn. To break ore with hammers so as to sort out the valuable portion.
b. Derb. A small solid pillar of coal left as a support for the roof.

coba

Uncemented sand or gravel underlying the nitrate (caliche) deposits of
Chile. See also:congela

cobalt

A tough, lustrous, nickel-white or silvery-gray, metallic element. Symbol,
Co. Occurs in the minerals cobaltite, smaltite, and erythrite; often
associated with nickel, silver, lead, copper, and iron ores, from which it
is most frequently obtained as a byproduct. Its alloys have unusual
magnetic strength and are used for high-speed, heavy-duty,
high-temperature cutting tools, and for dies, in jet turbines and gas
turbine generators. Its salts are used in porcelain, glass, pottery,
tiles, and enamels to produce brilliant blue colors.
Handbook of Chemistry and Physics, 3

cobalt bloom

Hydrated arsenate, Co₃ (AsO₄ )₂ .2H₂ O .
See also:erythrite

cobalt-bonded

Particles of a refractory material, such as powdered tungsten carbide,
cemented together with cobalt to form a metallike mixture. Long

cobalt glance

See:cobaltite

cobaltiferous wad

An impure hydrated oxide of manganese containing up to 30% cobalt; a
source of cobalt in Zaire.

cobaltite

a. An orthorhombic mineral, 4[CoAsS] ; pseudocubic; metallic; occurs in
high-temperature vein deposits associated with smaltite and in metamorphic
rocks; an important source of cobalt. Syn:cobalt glance; white cobalt;
gray cobalt.
b. The mineral group cobaltite, gersdorffite, hollingworthite, irarsite,
platarsite, tolovkite, ullmannite, and willyamite.

cobalt lollingite