The spraying of mine roadways with water or treatment with a wetting agent
in order to (1) increase the difficulty of raising the dust deposit into
the air to take part in an explosion, and (2) reduce the flammability of
the dust raised in an explosion. Nelson
a. When surface-active agents cause water to displace air at the surface
of a solid-water-air system, the surface tension of the solid-water phase
has been lowered in comparison with that of the solid-air phase, by
adsorption of the wetting agent (adhesional wetting). For a small
particle, wetting can be separated into three stages (adhesion, immersion,
spread). Wetting is a preliminary step in deflocculation. Pryor, 3
b. A condition in which the surface tension of the solid-water phase is
lowered in comparison with surface tension in the solid-air phase.
The weight (solids plus water) per unit of total volume of soil mass,
irrespective of the degree of saturation. Syn:mass unit weight
See also:unit weight
A horizontal beam in a bracing structure. Nichols, 1
A coal-cutter jib that enables water to be taken, during cutting, to the
back of the cut for dust suppression and prevention of gas ignition from
frictional sparking. With an undercutting jib, it consists of a feed water
pipe and four or five distributor pipes terminating in jets all arranged
in the top plate of the jib. See also:undercut ignition;
dust-suppression jib. Nelson
Corn. A mine. Nelson
Wheatstone-bridge-type instrument
An instrument that makes use of electrically heated filaments that burn
methane and measure the heat output by resistance pyrometry. One or more
filaments form the arms of a Wheatstone bridge circuit, the out-of-balance
current being a function of the methane percentage. Roberts, 1
The distance between the contact points on the front and back wheels of
any vehicle and the surface upon which the vehicle travels. CTD
A flat or landing on the top of an incline. Fay
A series of wheels supported in a frame over which objects are moved
manually or flow by gravity. See also:el conveyor; gravity conveyor;
gravity wheel conveyor; portable conveyor.
a. A wheel equipped with digging buckets, carried and controlled by a
tractor unit. Nichols, 1
b. A machine that digs trenches by rotation of a wheel fitted with toothed
buckets. Nichols, 1
A tool for cleaning, resharpening, and truing the cutting faces of
grinding wheels. Crispin
A tractor, fitted with large rubber-tired wheels, which can travel
comparatively fast over rough ground. See also:tractor
See:pusher
a. A yellowish resin, found in the Cretaceous beds of northern New Mexico,
filling the fissures of the lignite, or interstratified in thin layers. It
is soluble in ether. Fay
b. A yellowish variety of retinite that is soluble in ether and fills
fissures in, or is thinly interbedded with, lignite beds in northern New
Mexico.
A large-capacity machine for excavating loose deposits, particularly at
opencast coalpits. It consists of a large digging wheel that rotates on a
horizontal axle and carries large buckets on its rim. Nelson
See:rollerman
See:bournonite
A pit in which the lower part of a flywheel runs. Webster 2nd
The place in which a water wheel is set. Webster 3rd
See:incline man