a. A heavy drilling machine in which the drilling head is capable of
radial adjustment along a rigid horizontal arm carried by a stand.
See also:radial percussive coal cutter
b. A small diamond drill having a drilling head that can be adjusted
radially along a rigid horizontal arm radiating from a vertical column;
usually driven by air and used to drill radial blastholes underground.
See also:radial drilling
The drilling of a number of holes in a single plane and radiating from a
common point. CF:horadiam
A mine fan in which the air enters along the axis parallel to the shaft
and is turned through a right angle by the blades and discharged radially.
There are three main types with (1) backwardly inclined blades; (2) radial
blades; and (3) forward curved blades. In (2) and (3) the blades are made
of sheet steel, while in (1) the present tendency is to replace curved
sheet-steel blades by blades of aerofoil cross section. The aerofoil
bladed radial-flow fan has an efficiency of about 90%.
CF:axial-flow fan; mixed-flow fan. Nelson
In bituminous coal mining, a person who operates a radial-type coal
cutter. The machine remains stationary at the center of the working place
and undercuts or shears the coal in an arc rather than making a straight
cut by moving across the working face. Also called arcwall machineman.
DOT
A heavy coal cutter for use in headings and rooms in pillar methods of
working. The machine weighs about 12 hundredweight (545 kg) and is usually
mounted on a light carriage to suit the mine track. A percussive drill,
with extension rods, makes a horizontal cut about 5-1/2 ft (1.68 m) deep
and 15 ft (4.57 m) wide at any height in the heading. The central column
is tightened between roof and floor about 4-1/2 ft (1.37 m) from the face.
The machine can also be used for drilling shotfiring holes. Nelson
The radial pressure of wire rope is a function of the rope tension, rope
diameter, and tread diameter. The radial pressure can be determined by the
following equation: P = 2T/Dd, where P equals radial pressure in pounds
per square inch; T equals rope tension in pounds; D equals tread diameter
of sheave or drum in inches; and d equals rope diameter in inches.
A method of caving by which all the ground around a central raise might be
worked in a series of slices arranged like the spokes of a wheel.
Lewis
The change in length per unit length in a direction radially outward from
the charge. Duvall
a. Stress normal to the tangent to the boundary of any opening.
Obert
b. In the Earth, the stress normal to a spherical surface.
In a fan, the quantity of air delivered in cubic meters per second divided
by the outlet area of the fan at the periphery.
A ventilation system in which a number of downcast shafts arranged around
the periphery of the working area are served by a common upcast shaft
within the area, or vice versa. Sometimes known as compound ventilation.
BS, 8
A unit of plane angular measurement equal to the angle at the center of a
circle subtended by an arc equal in length to the radius. One radian
equals about 57.29 degrees . Webster 3rd
Energy that radiates or travels outward in all directions from a source.
MacCracken
Said of an aggregate of acicular crystals that radiate from a central
point. CF:spherulitic
See:marcasite
A mineral with crystals or fibers arranged around a center point, for
example, stibnite. Also called divergent. Nelson
The basic unit of absorbed dose of ionizing radiation. One radiation
absorbed dose (abbrev., rad) equals the absorption of 100 ergs of
radiation energy per gram of matter. Lyman
a. A general term for the alteration of properties of a material arising
from exposure to X-rays, gamma rays, neutrons, heavy-particle radiation,
or fission fragments in nuclear fuel material. ASM, 1
b. Damage done to a crystal lattice (or glass) by passage of fission
particles or alpha particles from the nuclear decay of a radioactive
element residing in or near the lattice. See also:metamict mineral
AGI
A device used either on the surface or in drill holes to detect and/or
indicate the occurrence or the nearby presence of radioactive minerals.
Also called electronic logger; gamma-ray detector; Geiger counter;
Geiger-Mueller counter; Geiger-Mueller probe; scintillation counter;
scintillometer. Long
¬M ü]f L`f ²? 2 DICTIONARY TERMS:radiation log See:radioactivity log
[\B]radiation log[\N]
a. A device for ascertaining the temperature of a distant source of heat,
such as a furnace. A concentrated group of thermocouples, called a
thermopile, is used. Radiant heat from the furnace or object is focused by
a lens onto the thermopile. Radiation pyrometers may be used for measuring
temperatures to 7,000 degrees F (3,870 degrees C). The device is used in
automatic control systems in mineral dressing and other processes.
Nelson
b. Pyrometer that determines temperature by measuring the intensity of
radiation from the hot body.
A study of factors in any process or device involving radiation that could
cause danger to any persons working near the process or device.
NCB