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gravity haulage

A system of haulage in which the set of full cars is lowered at the end of
a rope, and gravity force pulls up the empty cars, the rope being passed
around a sheave at the top of the incline. The speed of the haulage is
controlled by a band brake on the sheave. See also:brake incline;
underground haulage. Syn:jig haulage; self-act. Nelson

gravity inclines

Openings made in the direction of the dip of the deposit. The gradient of
the gravity incline is determined by the dip of the deposit. The ore mined
is transported through them, usually to the next lower level drive.
Stoces

gravity instruments

Devices for measuring the gravitational force or acceleration or its
gradient at any point. They are of three principal types: (1) a static
type in which a linear or angular displacement is observed or nulled by an
opposing force, (2) a dynamic type in which the period of oscillation is a
function of gravity and is the quantity directly observed, or (3) a
gradient-measuring type, for example, Eotvos torsion balance. AGI

gravity meter

a. Sensitive device for measuring gravitational variations.
Bennett
b. See:gravimeter

gravity plane

A tramline laid at such an angle that full skips running downhill will
pull up the empties. Fay

gravity plane rope haulage

See:self-acting rope haulage

gravity prospecting

Mapping the force of gravity at different places with a gravimeter
(gravity meter) to determine differences in specific gravity of rock
masses, and, through this, the distribution of masses of different
specific gravity. Leet, 1

gravity railroad

A railroad in which the cars descend by their own weight; an inclined
railroad. Standard, 2

gravity road

Any road on which cars will descend by gravity. Jones, 1

gravity roller conveyor

See:roller conveyor

gravity screen

A perforated steel plate, set at an angle, over which large coal or other
material slides by gravity to effect a primary classification.
Nelson

gravity separation

Separation of mineral particles, with the aid of water or air, according
to the differences in their specific gravities. AGI

gravity solution

A solution used to separate the different mineral constituents of rocks by
their specific gravities, as the solution of mercuric iodide in potassium
iodide having a maximum specific gravity of 3.19. Standard, 2

gravity stowing

A method of stowing in inclined conveyor faces, in which the material is
brought into the upper gate (usually the tailgate) and arranged to slide
down on trays which are moved forward as each track is filled.
Nelson

gravity takeup

See:belt tensioning device

gravity wheel conveyor

See:wheel conveyor

gray antimony

See:stibnite

grayband

A variety of sandstone for sidewalks; flagstone. See also:flagstone
Standard, 2

gray cast iron

A cast iron that gives a gray fracture due to the presence of flake
graphite; often called gray iron. See also:iron

gray cobalt

See:cobaltite; smaltite.

gray copper

See:tetrahedrite