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free ferrite

Ferrite in steel or cast iron other than that associated with cementite in
pearlite. CTD

free field stress

The stresses existing in rock before the excavation of any mine opening.
In general, these stresses are known to be influenced primarily by the
weight of the overlying material, the relation of the opening of the rock
masses around it (depth of overburden, etc.), the physical characteristics
to the surrounding rock, and tectonic forces. Lewis

free gold

a. Gold uncombined with other substances.
b. Placer gold.

free haul

The distance every cubic yard is entitled to be moved without an
additional charge for haul. Nichols, 1

free-milling

Applied to ores that contain free gold or silver, and can be reduced by
crushing and amalgamation without roasting or other chemical treatment.
Fay

free-milling gold

Gold with so clean a surface that it readily cyanides after liberation by
comminution.

free-milling ore

Ore containing gold that can be readily cyanided.

free moisture

a. Moisture in coal that can be removed by ordinary air drying.
CF:combined moisture
b. The part of the total moisture that is lost by a coal in attaining
approximate equilibrium with the atmosphere to which it is exposed.
BS, 4
c. Moisture not retained or absorbed by aggregate. Taylor
d. See:moisture content
e. Moisture removable by air-drying under standard conditions. Also called
surface moisture. BS, 5
f. See:free water

free on board

a. Price of consignment to a customer when delivered, with all prior
charges paid, onto a ship or truck. Pryor, 3
b. Free on rail (f.o.r.) describes similar delivery to rail.
Pryor, 3

free particles

Particles of ore consisting of a single mineral. Gaudin, 1

free-piston drive sampler

A drive-sample barrel in which a piston is free to move upward with the
top of the sample during the actual dry-sampling operation. Long

free radical

a. A chemical species that is uncharged and has one or more unpaired
electrons.
b. An atom or molecule with at least one unpaired electron.

free settling

As opposed to hindered settling in classification, free fall of particles
through fluid media. Pryor, 4

free share

Som. A certain proportion of a royalty on coal, paid to lessor by lessee.
Fay

free silica

Quartz occurring in granites. Mason

free split

In parallel ventilation flow, the branch or airway that does not require
artificial resistance (a regulator) to achieve its design air quantity.
See also:open split

freestone

Any stone (esp. a thick-bedded, even-textured, fine-grained sandstone)
that breaks freely and can be cut and dressed with equal ease in any
direction without splitting or tending to split. The ease with which it
can be shaped into blocks makes it a good building stone. The term was
originally applied to limestone, and is still used for such rock.
CF:flagstone

free streaming

A combustible gases roof layer flowing under the action of buoyancy
without ventilation. BS, 8

free wall

The wall of a vein filling that scales off cleanly from the gouge.
Schieferdecker

free water

a. Water that is free to move through a soil mass under the influence of
gravity. Also called ground water; phreatic water. ASCE
b. Water in soil in excess of hygroscopic and capillary water; also called
gravity water. Seelye, 1
c. The quantity of water removed in drying a solid to its equilibrium
water content.

free-water elevation

See:water table