See:lazulite
a. A commercial name for a building or paving stone of bluish-gray color;
specif. a dense, tough, fine-grained, dark blue-gray or slate-gray
feldspathic sandstone that splits easily into thin, smooth slabs and that
is extensively quarried near the Hudson River in New York State for use as
flagstone. The color is due to the presence of fine black and dark-green
minerals, chiefly hornblende and chlorite. The term is applied locally to
other rocks, such as dark-blue shale and blue limestone. CF:flagstone
AGI
b. A miners' term for chalcanthite.
c. A term applied locally to rocks such as dark-blue shale, blue
limestone, and bluish metabasalt (greenstone).
d. A highly argillaceous sandstone, of even texture and bedding, formed in
a lagoon or lake near the mouth of a stream.
Grade stakes whose tops indicate finish grade level. Nichols, 1
See:chalcanthite
A diamond that appears blue or bluish in transmitted white light or
against a white background; it reflects white light when viewed edge up at
right angles to the table. Hess
Derb. A dark tough vein filling that dulls the drills readily.
Laboratory apparatus in which mineral particles suspended in water are
syphoned through vertical tubes of increasing cross section, the fraction
failing to rise under determined conditions of upward flow reporting as a
subsieve fraction. Pryor, 3
See:bench mark
Used in the United States for obtaining additional information on the
yields of coke, tar, and gas that can be expected in high-temperature
practice. This is a vertical cylinder of mild steel holding up to 2
hundredweight (91 kg) of coal and operated at temperatures up to 1,000
degrees C. Francis, 2
See:bord
Eng. Coal having a fibrous or woody appearance. Fay
York. Headings driven in pairs generally to the rise, out of which banks
or stalls are opened and worked. Hess
The work done when a rate of working of 1 kW is maintained for 1 h. The
British unit of electrical energy; kilowatt-hour. Abbrev: B.O.T. unit.
Nelson
The amount of undercutting that can be done at one setting of a coal
mining machine, usually about 5 ft (1.5 m), without moving forward the
board upon which the machine works. Fay
See:bort
See:bort
A gold dredge.
a. Aust. A catch placed between the rails of the upline of an incline to
stop any runaway trucks. It consists of a bent iron bar, pivoted in such a
manner that the downhill end is slightly heavier than the uphill end,
which is capable of being depressed by an upcoming truck, but rises above
the level of the truck axle as soon as the truck is past. Syn:monkey;
monkey chock. Fay
b. A spool or reel. Fay
A volcanic crater or vent. Standard, 2