A wire rope with alternate strands right and left lay. Hunt
See:ream back
reversible auxiliary ventilation
In this system, a single duct is provided and is normally operated by a
blowing fan. After blasting, airflow is reversed and the fumes and dust
are exhausted. Ventilation is again reversed to blowing, when the work at
the face is resumed. The usual arrangement is to use two fans, one for
forcing, one for exhausting, at the mouth of the heading. This arrangement
is particularly suited to underground use as it allows clean air to be
drawn from, and contaminated air to be discharged to, separate points in
the main airways. See also:auxiliary ventilation;
two-fan auxiliary ventilation.
reversible endless-rope system
A haulage system in which a single rope is used passing around a surge
wheel. A single track may be used or, if more than one train is hauled, a
single track with passbys, or a three-rail system with passbys, that
eliminates facing points, may be used. The system may be operated at
higher speeds than normal endless systems since the trains are attached
and detached from a rope at rest; it has been used for the haulage of
workers at speeds up to 12 mph. Extra rope must be spliced onto the rope,
and the return wheel moved forward, when the system is extended.
Sinclair, 5
A forward-and-reversing transmission that is shifted by a pair of friction
clutches. Nichols, 1
The system of doors or shutters on or near a surface radial-flow fan for
reversing the direction of the air passing through a mine. BS, 8
A molding machine having a flask or flasks that may be turned over for
ramming the sand. Standard, 2
A type of rolling mill in which the stock being mechanically worked by
rolling passes backwards and forwards between the same pair of rolls,
which are reversed between each pass. See also:continuous mill;
three-high mill. CTD
A shaft whose direction of rotation can be reversed by the use of clutches
or brakes. Nichols, 1
A mercury-in-glass thermometer used to measure temperatures of the sea at
depth. The temperature is recorded when the thermometer is inverted; and
the recording is maintained until it is once again upright. A protected
thermometer and an unprotected thermometer are usually used as a pair,
attached to a Nansen bottle. AGI
a. A facing, sheathing, or retaining wall of masonry or other materials
for protecting a mass or bank of earth, etc., as in fortifications and
riverbanks. Standard, 2
b. A wall sloped back sharply from its base. Nichols, 1
An obsolete term for a time of profound orogeny and other crustal
movements, on a continentwide or even worldwide scale, the assumption
being that such revolutions produced abrupt changes in geography, climate,
and environment. See:orogeny
A screen consisting of a cylindrical (sometimes conical) screening surface
mounted on a revolving frame for sizing coarse material; it is still
common in gravel-washing, coal-washing, and stone-treating plants, but is
not widely used in ore dressing. See also:trommel; trommel screen.
Newton, 1
A digging machine that has the machinery deck and attachment on a vertical
pivot, so that it can swing independently of its base. Nichols, 1
The rotary washing screen is cylindrical in shape and made of three
sections--a scrubber, a sand jacket, and a gravel-screening
section--mounted on a steel frame. Pit and Quarry
To re-treat a product in the same or in another washer. BS, 5
A washbox to which the product (or a portion thereof) of a previous
washing operation is fed for additional treatment. BS, 5
See:revdanskite
Said of components derived from an older sedimentary formation and
incorporated in a younger one.