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rotational transformation

An isochemical phase change involving only a shift in angle of chemical
bonds, e.g., beta-quartz to alpha-quartz. CF:phase transformation;
displacive transformation; reconstructive transformation;
dilational transformation.

rotational wave

See:S wave

rotation firing

Crushing a small piece of rock with a first explosion, and timing other
holes to throw their burdens toward the space made by that and other
preceding explosions. Also called row shooting. Nichols, 1

rotation recorder

An instrument for measuring any slight rotation of a bridge support under
load. See also:spread recorder

rotch

See:rotche

rotche

S. Staff. A soft and moderately friable sandstone. Also called roach;
rotch; roche.

rothoffite

A brown variety of andradite garnet.

Rot I plate

See:gypsum plate; selenite plate.

rotobelt filter

Drum-type vacuum filter in which the membrane is a belt, which leaves the
drum at discharge point and is returned via pulleys. This arrangement
facilitates washing of filter cake from both sides, also discharge.
Pryor, 3

roto finish

A tumbling method using special chips and chemical compounds.
Osborne

rotor

Any unit that does its work in a machine by spinning and does not drive
other parts mechanically. Nichols, 1

rotor steel process

A steelmaking process using the principle of rotation as in the Kaldo
process. It has two lances; one above the bath surface uses low-pressure
oxygen to burn carbon monoxide from the bath, while the other blows oxygen
onto the bath at high pressure to obtain similar fast oxidation as in the
L.D. steel process. Nelson

rotten reef

S. Afr. Decomposed, soft country rock found in connection with auriferous
conglomerates.

rottenstone

A soft, light, earthy substance consisting of fine-grained silica
resulting from the decomposition of siliceous shale-on limestone. It is
used for polishing. CF:diatomite

rough

a. Highly fractured, broken, or cavey ground. Long
b. An uncut gemstone. Pertaining to an uncut or unpolished gemstone; e.g.,
a rough diamond. AGI

roughbacks

Term used in the dimension stone industry for ends of blocks that are used
as byproducts.

rough diamond

A diamond in its natural state. Long

rougher cell

Flotation cells in which the bulk of the gangue is removed from the ore or
coal.

rough ground

Highly fractured, fragmented, or cavey rock formations. Long

roughing

Upgrading of run-of-mill feed either to produce a low-grade preliminary
concentrate or to reject valueless tailings at an early stage. Performed
by gravity on roughing tables, or in flotation in rougher circuit.
See also:cleaning

roughing hole

A hole to receive slag from a blast furnace, or molten iron when it is
undesirable to let it run into pigs. Standard, 2