A generic term for class of hydrated silicates of aluminum and either sodium or calcium or both, of the type Na2 O.Al2 O3 .nSiO2 .xH2 O . The term originally described a group of naturally occurring minerals. The natural zeolites are analcite, chabazite, heulandite, natrolite, stilbite, and thomsonite. Artificial zeolites are made in a variety of forms, ranging from gelatinous to porous and sandlike, and are used as gas adsorbents and drying agents as well as water softeners. Both natural and artificial zeolites are used extensively for water softening. The term zeolite now includes such diverse groups of compounds as sulfonated organics or basic resins, which act in a similar manner to effect either cation or anion exchange.
A gray or white, malleable, ductile, metallic element. Symbol, V. Found in about 65 different minerals, among which are carnotite, roscoelite, vanadinite, and patronite; also found in phosphate rock, certain iron ores, and some crude oils. About 80% of the vanadium now produced is used as a ferrovanadium or as a steel additive; also used in ceramics, as a catalyst, and in the production of a superconductive magnet.
A hexagonal mineral, BeMg3 Al8 O16 ; hoegbomite group; a dimorph of musgravite; violet-red.
A large brick or tile; esp., a curved firebrick used to support melting pots for zinc and retort covers.
A lemon-yellow pigment consisting of barium chromate.
Underground Glory-hole Method
A method used in large deposits with a very strong roof. In this method, a deposit is divided by levels and on every level chutes are raised to the next one. Mining starts from the mouth of the chutes in such a way as to develop a funnel-shaped excavation (mill, glory) with slopes so steep that the broken ore falls into the chutes and thus to the cars on the lower level. A sufficiently strong pillar is left for protection at the higher level. Syn: underground milling
A mineral deposit found in a deeply eroded mass of intrusive rock with few roof pendants remaining.
A mineral, (Ag,Au)Te ; soft; heavy; gray-white; in tabular crystals with perfect cleavage; an ore mineral.
A monoclinic mineral, (Na,Ca)2 (Mn,Fe)3 (PO4 ) (sub 3) ; alluaudite group; forms dull olive-green granular masses; at Varutrask, Sweden.
A monoclinic mineral, BaAl2 Si2 (O,OH)8 .H2 O; pseudohexagonal; at the Benalt manganese mine, Wales. Named from Cymru, the Welsh name for Wales.