In ore dressing, smelting, and refining, a person who maintains flow of
molten lead from the blast furnace to the lead pot for removal to
refinery. DOT
a. In blasting, the heavy wires that connect the firing current source or
switch with the connecting or cap wires. Nichols, 1
b. Two insulated copper wires leading from the battery or igniting
apparatus to the primer cartridge in an explosive charge. Also called
connecting wires. Stauffer
A place where lead is extracted from the ore. Fay
PbZrO3 ; a ferroelectric material. It is also used in lead
titanate-zirconate (P.Z.T) piezoelectric ceramics. Dodd
A very thin sheet or plate of metal, as gold. Standard, 2
See:book clay
a. Any of various linear units of distance, ranging from about 2.42 to 4.6
statute miles (3.89 to 7.4 km); esp. land league (an English land unit
equal to 3 statute miles or 4.83 km) and marine league (a marine unit
equal to 3 nmi or 5.56 km). AGI
b. Any of various units of land area equal to a square league; esp. an old
Spanish unit for the area of a tract 5,000 varas square, equal to 4,428.4
acres (1,792.1 ha) in early Texas land descriptions or equal to 4,439
acres (1,796 ha) in old California surveys. AGI
Low-grade mineralized rock into which an orebody degenerates. Hess
An unintentional diversion of ventilation air from its designed path.
BS, 8
A numerical expression of a duct's liability to leak. The National Coal
Board of Great Britain defines this as the volume of air in cubic feet per
minute that would leak from 100 ft (30 m) of a ventilation duct under a
uniform pressure of 1 in (2.54 cm) of water gage. Roberts, 1
A dispersion pattern formed by the movement of ore-forming fluids in the
rock overlying a mineral deposit.
An additional intake that is a component part of a system of controlled
leakage. BS, 8
A ventilation circuit with two adjacent intake roadways leading to the
coalface. The method has been criticized because the air flow may become
so sluggish as to cause combustible gases layers. See also:two intakes
Nelson
The resistance between the blasting circuit, including lead wires, and the
ground. Atlas
An instrument that detects leaks in water, oil, gas, steam, and air lines
by amplifying the sound produced by the escaping fluid. Osborne
a. Of ore, low-grade; submarginal; unpay; of doubtful exploitable value.
Pryor, 3
b. A rock in which the minerals sought occur in much less than exploitable
amounts. Long
c. See:hang
d. See:low-grade
A clay of low to medium plasticity owing to a relatively high content of
silt or sand. CF:fat clay
A low-grade ore. See also:lean; natural ore. Nelson
Eng. A dislocation of strata by faulting.
A system employed with self-advancing supports on a longwall face in which
alternate supports are advanced on each web of coal removed. To do this,
alternate units have to be moved a distance equal to twice the web
thickness--half before snaking and half after snaking. Nelson
See:lehr