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dumping wagon

See:dumper

dump leaching

Term applied to dissolving and recovering minerals from subore-grade
materials from a mine dump. The dump is irrigated with water, sometimes
acidified, which percolates into and through the dump, and runoff from the
bottom of the dump is collected and mineral in solution is recovered by a
chemical reaction. Commonly used to recover gold and copper.
See also:heap leaching

dumpling

A mass of ground left undisturbed until the final stages of excavation,
when it is removed. In the intermediate stages it may be used as a support
for timbering to the excavations. Hammond

dump motorman

In bituminous coal mining, one who operates a mine locomotive (motor) to
haul cars of dirt, rock, slate, or other refuse to the dump at the surface
of an underground mine. Also called dirt-dump engineer; refuse engineer.
DOT

dump room

Space available for disposing of waste from a mine.

dump skip

A skip with an attachment that dumps the load automatically. Fay

dump wagon

A large-capacity side-, bottom-, or end-discharge wagon (or skip) on tired
wheels or crawler tracks; usually tractor towed. Nelson

dundasite

An orthorhombic mineral, PbAl2 (CO3 )2 (OH)
4 .H2 O ; secondary; in aggregate tufts of minute, radiating
needles.

dunite

Peridotite in which the mafic mineral is almost entirely olivine, with
accessory chromite almost always present. Named by Hochstetter in 1864
from Dun Mountain, New Zealand. AGI

Dunkard series

Continental strata, including thin coal seams, similar to the
Pennsylvanian, but of Permian age, occurring in North America. Strata of
the same age are marine in Kansas, but include marginal red beds with
gypsum, and thick salt deposits were formed later in the Kansas Basin.
CTD

duns

A term used in SW England for a shale or massive clay associated with
coal. AGI

dunstone

a. A term used near Matlock, England, for a hard granular yellowish or
cream-colored magnesian limestone. AGI
b. A term used in Wales for a hard fireclay or underclay, and in England
for a shale. AGI

Duobel

Trademark for high-velocity permissible explosives furnished in seven
grades based upon velocity and cartridge count; poor water resistance.
Used for mining coal where lump coal is not a factor. CCD, 2

duoflex checker system

A checker arrangement for hot-blast stoves. The gas used is only partially
cleaned and may contain from 0.5 to 1.5 g of dust per cubic meter of gas.
The top zone of the checkers is formed of straight-walled vertical
passages, and the middle zone of vertical passages in each of which two
opposite walls are continuously curved and the other two are straight,
while the bottom zone is formed of vertical passages in each of which all
four walls are continuously curved. Osborne

duplex breaker

A breaker having more than one crushing chamber.

duplex channeler

A type of channeling machine that cuts two channels simultaneously.

duplex compressor

Two compressors, side by side, and made in the combination of simple steam
and simple air cylinder, simple steam and compound air cylinders, or
compound steam and compound air cylinders.
See also:air-conditioning process

duplexing (duplex process)

Any two-furnace melting or refining process. ASM, 1

duplex pick

A coal-cutter pick that allows a cut to be made in either direction
without turning the pick. It is drop forged with a tip of fused tungsten
carbide. Nelson

duplex pump

A positive displacement pump with two water or liquid cylinders side by
side and geared so that the piston strokes in the cylinders alternate.
Such a pump may be either single or double action, depending on the number
and placement of intake and discharge valves on the cylinder and may be
designed so as to deliver a low volume of liquid at high pressures.
CF:centrifugal pump; triplex pump. Long

duplex pump

Displacement pump for handling pulps. Two cylinders are so geared that one
piston falls while other rises. Can lift small tonnages to good heights.
Pryor, 3