A trigonal mineral, Bi4 (S,Se)3 ; the selenium-rich analog
of laitakarite, similar to jose#1.ite but containing no tellurium; at the
Ikuno Mine, Hyogo Prefecture, Japan.
A monoclinic mineral, (Mn,Zn,Fe)SO4 .4H2 O ; rozenite group;
a green, friable crystalline aggregate in Hall Valley, Park County, CO.
An amorphous mineral, Mo3 O8 .nH2 O(?) .
A heavy flywheel used in the Ward-Leonard control of winding engines in
mine hoists. It is mounted on the shaft of a motor generator, which draws
on this source of energy as the hoist starts to move. Pryor, 3
A modification of the Ward-Leonard system of speed control, in which a
heavy flywheel is carried on the motor-generator shaft to smooth out peak
loads, which would otherwise be taken from the power supply. The system is
used on mine winding engines, etc. See also:Ward-Leonard control
Nelson
Scot. Noxious gas, as from underground fires or chokedamp; a stagnant
state of the atmosphere underground. Fay
A mine that has not obtained the necessary permits and licenses from the
appropriate State and Federal agencies before commencement of mining.
A thin extraneous crust formed on minerals. Standard, 2
a. Melting or infusing. Webster 2nd
b. Mixture of metallic and earthen substances. Webster 2nd
A general term for a group of three-layer (14Aa), micalike clays (K,H (sub
3) O)(Al,Mg,Fe)2 (Si,Al)4 O10 [(OH)2 ,H (sub
2) O] ; widely distributed in argillaceous sediments and derived soils;
intermediate in composition and structure between muscovite and
montmorillonite; contains less potassium and more water than muscovite,
but more potassium than kaolinite or montmorillonite; potassium is
generally replaced by calcium and/or magnesium; named from studies by
Grimm of shales and clays in Illinois. See also:muscovite
CF:pholidoide; phyllite. Syn:hydromica; hydromuscovite; glimmerton.
a. A trigonal mineral, FeTiO3 ; ilmenite group; forms two series
with geikielite and with pyrophanite. Iron-black. Also called menaccanite;
titanic iron ore. See also:zircon group
b. The mineral group geikielite, ilmenite, and pyrophanite.
See also:basonomelane
A hypabyssal rock composed almost entirely of ilmenite, with accessory
pyrite, chalcopyrite, pyrrhotite, hypersthene, and labradorite.
CF:nelsonite
A tetragonal mineral, (Ti,Nb,Fe)3 O6 ; forms a series with
strueverite in which tantalum substitutes for niobium; black; sp gr, 5.14.
Syn:iserine
An orthorhombic and monoclinic mineral, CaFe2 FeSi2 O (sub
7) O(OH) ; in prisms with vertically striated faces; compact, massive, or
fibrous; in some magnetite orebodies, in zinc and copper ores, in contact
deposits in dolomitic limestone, and in sodalite syenite near Julianehaab,
Greenland. Syn:elbaite; lievrite.
A rock composed of quartz and albite, formed by interaction between a
nepheline-syenite magma and graywacke. Holmes, 2
a. Formation of feldspathic minerals by penetration of alkaline solutions
of magmatic origin into aluminum-rich metamorphic rocks. AGI
b. The absorption of a fluid, usually water, by a granular rock or any
other porous material, under the force of capillary attraction, and in the
absence of pressure. AGI
a. A sedimentary structure characterized by imbrication of pebbles all
tilted in the same direction, with their flat sides commonly displaying an
upstream dip. Syn:shingle structure
b. A tectonic structure displayed by a series of nearly parallel and
overlapping minor thrust faults, high-angle reverse faults, or slides, and
characterized by rock slices, sheets, plates, blocks, or wedges that are
approx. equidistant and have the same displacement and that are all
steeply inclined in the same direction (toward the source of stress).
AGI
See:synthetic stone; assembled stone.
See:end-bump table
Lowest layer or layers of rock immediately above an underground opening.
See also:roof; nether roof.
An accessory for a gemological microscope containing a liquid of high
refractive index and designed to eliminate reflections from highly
polished facets and thus to expedite the observation of determinative
inclusions, growth lines, etc.