See:diabandite
a. In strata control, a term used to describe an area where the force is
much less than would be expected after considering the depth and type of
strata. CF:overstressed area
Mason
b. A region of low stress behind the walls of a stoped-out region.
Issacson
In deep mining, relief of pressure concentrations induced by mining or
caused by geological factors. Performed by drilling and blasting to loosen
the zones of peak stress. The peak load surrounding the excavation walls
is thus transferred deeper into the undisturbed rock, and a protective
barrier is formed. Pryor, 3
The distillation of solid substances accompanied by their decomposition.
The destructive distillation of coal results in the production of coke,
tar products, ammonia, gas, etc. CTD
Testing methods, the use of which destroy or impair the part or product
insofar as its intended use is concerned, but which give proof or an
indication of the strength or quality of similar or duplicate parts or
products. Such tests involve the subjection of the test piece to various
influences, of destructive magnitude, such as impact, stress, pressure,
cyclic movement, etc. See also:nondestructive testing
Henderson
The removal of a high proportion of sulfur from steel by injection of
calcium or magnesium. Nelson
To free from sulfur; to remove the sulfur from an ore or mineral by some
suitable process, as by roasting.
A drilling bit that is threaded or tapered and is removable from the drill
steel; not formed as an integral part of the drill steel. The all-steel
bit can be resharpened, but the tungsten carbide insert type may be
nonresharpenable. Also known as rip bit or knockoff bit. See also:bit;
hot miller.
See:head pulley
An appliance that releases automatically the winding rope from the cage
should an overwind occur. See also:wedge guide
See:decollement
A large-scale drawing showing all small parts, details, dimensions, etc.
Nichols, 1
The final soil tests at site as guided by the general soil survey. The
tests may be performed in situ by mobile laboratory units, or the samples
are sent to the nearest soils laboratory. See also:general soil survey;
preliminary soil survey. Nelson
A nonelectric system of initiating blasting caps in which the energy is
transmitted through the circuit by means of a low-energy detonating cord.
Dick, 2
a. See:magnetic detector
b. See:seismometer
c. The component of a remote-sensing system that converts electromagnetic
radiation into a signal that can be recorded. See also:pickup
Syn:radiation detector
d. See:sensor
The science of differentiating (1) between the various gemstones, (2)
between gemstones and their substitutes, and (3) among such substitutes.
See also:gemology
That branch of mineralogy that comprises the measurement of the nature,
composition, and classification of minerals by means of physical tests
(e.g., density, hardness), chemical analyses both qualitative and
quantitative, spectrochemical analyses including both absorption and
emission spectra, electron probe microanalyses, autoradiography, thermal
analyses, optical tests in both transmitted and reflected light, electron
microscopy, diffraction of X-rays or electrons, and crystallographic
analyses.
Treatment by chlorination of tinbearing scrap for recovery of tin as its
chloride. Pryor, 3
To cause to explode by the application of sudden force.
Standard, 2
A flexible cord made of wound hemp or jute threads covered with plastic
containing a center core of high explosive (PETN) and used to initiate
other explosives.
A fuse consisting of high explosive that fires the charge without the
assistance of any other detonator. It consists of a high-explosive core of
pentaerythritol tetranitrate (PETN) enclosed in tape and wrapped with
textile countering yarns. Usually, this fuse is then reinforced or
completely enclosed in a strong waterproof plastic outer cover. The
finished external diameter is normally about 0.2 in (5 mm). Primacord is
the best known brand. See also:Cordtex; safety fuse.
Fay; McAdam, 2; Nichols, 1; Nelson