The value used when calculating the slenderness ratio of pillars and
struts. If A is the cross-sectional area in inches of the pillar or strut
and I is its moment of inertia, the radius of gyration is (I/A), generally
known as K. Hammond
In crater tests, the average distance from the center of the explosive
charge to the periphery of the crater at the surface. Duvall
a. The ratio of the radius of the smaller ion to that of the larger ion.
It may not exceed 1. Hurlbut
b. The ratio of the radius of the smaller ion to that of the larger;
commonly cation to anion. Radius ratios are used to predict coordination
numbers of anions about cations in ionic crystal structures.
CF:Pauling's rules
a. A heavy, radioactive, gaseous element; inert; the heaviest known gas.
Symbol, Rn. Formed by the disintegration of uranium. Used similarly to
radium in medicine. Radon build-up is a health consideration in uranium
mines. Handbook of Chemistry and Physics, 3
b. Heaviest known gas. Colorless as a gas; yellow to orange-red,
phosphorescent, opaque crystals; sp gr of liquid, 4.4 (at -62 degrees C);
and of solid, 4.0; soluble in water; and slightly soluble in alcohol and
in organic liquids. All 18 known isotopes from radon-204 to radon-224 are
radioactive. Radon-222 emanates from thorium; half-life, 54.5 s; and an
alpha particle emitter; and radon-219 or actinon emanates from actinium;
half-life, 3.92 s; and an alpha particle and a gamma ray emitter. One part
of radon exists in 1 sextillion parts of air.
Handbook of Chemistry and Physics, 2
A radioactive element produced in the disintegration of radon.
Syn:radon progeny
The short-lived decay products of radon, an inert gas that is one of the
natural decay products of uranium. The short-lived radon progeny (i.e.,
polonium-210, lead-214, bismuth-214, and polonium-214) are solids and
exist in air as free ions or as ions attached to dust particles. The U.S.
Mine Safety and Health Administration has established radiation protection
standards that limit a miner's radon progeny exposure to a concentration
of 1.0 WL and an annual cumulative exposure to 4 WLM. Each WLM is
determined as a 173-h cumulative, time weighted exposure.
Syn:radon daughter
The aqueous solution remaining after the metal has been extracted by the
solvent; the tailing of the solvent extraction system.
See:float coal
A method of mine timbering in which the timbers appear like roof rafters.
a. The transporting of sediment, rocks, silt, and other matter of land
origin out to sea by ice, logs, etc., with subsequent deposition of the
rafted matter when the carrying agent disintegrates. Hunt
b. Matting or agglomerating of powdered coal. Bennett
a. In British usage, any of various hard, coarse, rubbly, or shelly rocks
that weather with a rough irregular surface; e.g. a flaggy sandstone or
limestone used as a building stone. The term appears in certain British
stratigraphic names, as the Kentish Rag (a Cretaceous sandy limestone in
East Kent). Syn:ragstone
b. Any of various hard rocks, as a quartzose mica schist used for
whetstones or a hard limestone used in building. Webster 3rd
c. A large roofing slate left rough on one side. Webster 3rd
d. To break (ore) into lumps for sorting; to cut or dress roughly (as a
grindstone). Webster 3rd
Rolls with rough surfaces to facilitate the gripping of the steel in the
first stages of rolling, as distinguished from the smooth-finishing rolls.
Mersereau, 2
a. The rough washing or concentration of ore or slimes on a rag frame.
Nelson
b. In roll crushers, grooves cut in surface to improve grip on feed, and
increase angle of nip. Also, in ore concentration in jigs, oversized
bedding placed on jig screens. Pryor, 3
c. See:bedding
Thin-bedded or flaggy sandstone. TIME
See:rag
The chain or inner surface of a crawler. Nichols, 1
The distance or width between the inner edges of the heads of the rails;
(1) in coal mining, the rail gage for tub and car tracks ranges from 2 to
3 ft (0.6 to 0.9 m), and 2-1/3 ft (0.7 m) is considered a satisfactory
compromise; (2) the standard gage for railway tracks is 4 ft, 8-1/2 in
(1.44 m) and, (3) in metal mining, the rail gage ranges from 1-1/2 to
2-1/2 ft (0.46 to 0.76 m). See also:track gage
A materials transportation system consisting of gondola cars, and the
steel rails on which the cars are moved about with a suitably powered
traction unit as a locomotive.
These may be either longitudinal or transverse and consist of rails of
various sizes, placed in sets usually upside down, either longitudinally
in the sluice box, or transversally across the box. They wear well, are
rigid, and give some security against theft of gold from the sluice boxes.
Griffith
Specially shaped steel bars which, when laid parallel on crossties and
fastened, form a track for vehicles with flanged wheels.
Material placed around and between track ties and tamped under sides and
ends of the ties to bring the track to proper grade by filling the space
between the bottom of the ties and the graded roadbed.