An oven for heating glass in the process of annealing; a leer.
Standard, 2
a. A form for building tunnel inverts. Stauffer
b. A pattern device used as a guide to mark points at which boreholes are
to be collared in ring drilling. Long
An adjustment, such as leveling or focusing, made to a surveying
instrument at each setup. See also:permanent adjustment
Hammond
The carbonate component of water hardness, which can be destroyed by
boiling. See also:hard water
In coal mining; during roof bolting process, vertical posts are installed
tight with wedges near the area where the next roof bolt will be
installed. These are installed by reaching from a bolted area of the roof.
Installed to support potentially loose roof to prevent fall onto persons.
A timber or steel lining inserted for a limited period until a permanent
shaft support is installed. See also:skeleton tubbing
According to the Federal Coal Mine Safety Act, a temporary splice is one
that does not have a rubber or neoprene jacket vulcanized over the splice
and bonded to the cable jacket. USBM, 3
a. The property of the particles or molecules of a substance to resist
separation; tensile strength. AGI
b. The force of strength with which the particles (or molecules) of a
mineral or rock hold together or resist separation. The terms commonly
used to describe the tenacity of a mineral are friable, brittle, sectile,
malleable, flexible, elastic, and tough. Stokes
a. Said of roof shale that tends to break up or crush under pressure into
small fragments and that will not hold in any span over a few inches. Also
called short. Raistrick
b. The formal offer by the tenderer to carry out the work described in the
drawings and/or specification for a certain sum of money.
See also:agreement
An isometric mineral, (Cu,Fe)12 As4 S13 ;
tetrahedrite group; forms a series with tetrahedrite; may contain zinc,
silver, or cobalt replacing copper; in veins; an important source of
copper. Syn:gray copper ore
A projecting tongue fitting into a corresponding cavity called a mortise.
Fay
See:grade
A monoclinic mineral, CuO ; occurs in gray scales, black powder, or earthy
masses; sp gr, 6.4; in oxidized zones of copper deposits; a source of
copper. Syn:melaconite; black copper. See also:black copper ore
A force such as the force applied when a haulage rope pulls a set of tubs.
Morris
The maximum applied tensile stress that a body can withstand before
failure occurs. Syn:tenacity
AGI
A normal stress that tends to cause separation across the plane on which
it acts. CF:compressive stress
A test in which material is subjected to an increasing tensile pull until
it fractures. A stress-strain curve may be plotted, and the limit of
proportionality, proof stress, yield point, ultimate tensile stress,
elongation, and reduction in area can be determined. CTD
a. In subsidence, the amount of lengthening per unit of measurement.
Nelson
b. In engineering, a pulling force or stress; metals in tension are
strong, while concrete and masonry are weak. Nelson
c. A system of forces tending to draw apart the parts of a body, esp. of a
belt, a line, a cord, or a sheet, combined with an equal and opposite
system of resisting forces of cohesion holding the parts of the body
together. The stress caused by pulling; opposite of compression and
distinguished from torsion. Standard, 2
d. Sometimes used in place of voltage or electromotive force.
See also:tension zone
A bogie or frame carrying a pulley around which the rope of an endless
rope haulage passes to be tensioned or tightened. The bogie moves on rails
and may be kept taut by balance weights or placed on an inclined roadway
(with sufficient weights) to move up or down according to the tension in
the endless rope. A tension device is necessary to take up any slack rope
created by varying loads on the haulage system. Nelson
A hydraulic piston and cylinder mechanism that can be attached to a
rotary-drill feedoff line and adjusted to allow the drill stem to feed
downward while maintaining a constant preset tension on the drill string.
See also:tension drilling