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Result search of : R
Title Description
 Reconnaissance Map   A map incorporating the information obtained in a reconnaissance survey and data obtained from other sources.  
 Rziha’s Theory   A mine subsidence theory that is a variant or extension of the vertical theory. In this theory, allowance is made for movements beyond the undermined area, but the dip of the beds is considered to be of little or no influence. Rziha maintained that if rock is undercut, it will stay undisturbed if cohesion exceeds gravity and will fall if gravity exceeds cohesion.  
 Red Cobalt   A monoclinic mineral, 2[Co3 (AsO4 )2 .8H2 O] ;
forms a series with annbergite and with hoernesite; occurs in soft pink to
crimson crystals, globular or reniform masses, or earthy encrustations as
a weathering product of cobalt ores in the oxidized parts of
nickel-arsenic-silver-bearing veins; used as ore indicator for cobalt and
possibly silver.  
 Red Lead Ore   A monoclinic mineral, PbCrO4 ; bright-red, yellowish-red, or
orange.  
 Red Lime Mud   A red mud to which lime, caustic soda, or quebracho, has been added. The pH is usually 12.0 to 13.0.  
 Recomposed Rock   A rock produced in place by the cementation of the fragmental products of surface weathering; e.g. a recomposed granite. The term has been applied to a rock of intermediate character straddling an unconformable surface between the breccia of the lower formation and the conglomeratic base of the upper formation.  
 Raw Mica   A term commonly used for unmanufactured mica.  
 Red Iron Ore   A trigonal mineral, alpha -Fe2 O3 ; red if earthy,
reddish to bluish gray if massive, or bright metallic steel-gray in thin
tablets or micalike flakes (specular hematite); invariably has red ocher
streak. Kidney ore is massive reniform hematite. Commonly associated with
quartz, oxyhydroxides such as goethite or limonite, and magnetite, after
which it may be pseudomorphic; nonmagnetic when pure, but may appear
magnetic due to residual or included magnetite or maghemite; the most
widely mined ore of iron; in sedimentary rocks, Precambrian banded iron
formations (including their metamorphosed equivalents), oolitic
ironstones, contact-metamorphic deposits, commonly by alteration of
magnetite; may be of secondary origin, having formed by oxidation and
decomposition of iron silicates and carbonates; also occurs as a primary
mineral in veins and replacement deposits associated with igneous
intrusions, and in fumarolic deposits from volcanic gases.  
 Rack   A. An inclined trough for washing or separating ore.
B. A toothed or notched drill-base-slide and meshing-gear pinion used to facilitate the moving of a drill to clear the borehole when hoisting or lowering the drill string; generally limited to larger, skid-mounted machines.
C. A framework of wood or metal for the orderly storage of core, pipe rods, etc., in a horizontal position.
D. A tilting table on which concentrates are separated from the passing flow of finely ground pulp, the system being arranged to be periodically self-flushing.
E. A screen composed of parallel bars to catch floating debris.
F. In electroplating, a frame used for suspending and conducting current to one or more cathodes during electrodeposition. 
 Recrystallization   A. The diagenetic process by which unstable minerals in buried sediment are transformed into stable ones.

B.The formation, essentially in the solid state, of new crystalline mineral grains in a rock. The new grains are generally larger than the original grains, and may have the same or a different mineralogical composition. 
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