To stay, prop up, or support by braces.
Timbers braced against a wall as a temporary support. Also, the timbering
used to prevent a sliding of earth adjoining an excavation.
Crispin
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 tender. Raistrick
b. Brittle; friable; breaking or crumbling readily; inclined to flake off;
said of coal.
c. Used to denote a roof that has very little structural strength.
TIME
A direction of more than 45 degrees to the main natural line of cleat or
cleavage in the coal. Also spelled horn. CF:long awn
See:short
A column so short in relation to its cross section that, if overloaded, it
will fail by crushing rather than by buckling. CF:long column
Hammond
a. A method of blasting where the explosive charges are detonated with a
very short delay interval between them. It enables shots to assist one
another as in simultaneous firing, and also each shot or group of shots
establishes a free or semifree face for the following group of shots.
Nelson
b. Method of blasting by which charges are caused to explode in a given
sequence with time intervals of 0.001 to 0.1 s. Fraenkel
a. A detonator in which the interval of time delay is incremental in
milliseconds. Syn:millisecond-delay detonator
b. The original 1-s delay detonators are no longer used, and the choice
now lies between the one-half-second type and those known as short-delay
detonators. These give better fragmentation of rock and consequently
better loading rates. Nelson
short-delay electric detonator
An electric detonator with a designated delay period of 25 to 1,000 ms.
CFR, 4
Taphole in a furnace that is not properly stopped and that is likely to
release the molten charge prematurely. Henderson
Diamond drilling where the length of borehole generally does not exceed
100 ft (30 m). Long
The time required to drill a few holes for trolley hangers or a few short
block holes, or one or two holes for bringing down a piece of loose roof.
An electric blasting cap that explodes one-fiftieth to one-half second
after passage of an electric current. Syn:millisecond delay
Nichols, 1
a. Identical first-neighbor coordination of atoms. Typical of glassy
structures. Van Vlack
b. A structural state in which cations have coordination polyhedra as
predicted by radius ratios but lack the long-range order of crystallinity;
e.g., silicate glasses. CF:long-range order
c. The type of order in which the probability of a given type of atom
having neighbors of a given type (for example, that an Alpha atom is
surrounded by Beta atoms) is greater than would be expected on a purely
random basis. There is thus a tendency to form small ordered domains, but
these do not link together at long distances.
To be forced by adverse conditions or core blockage to pull the drill
string before the core barrel being used is filled to capacity with core.
CF:long run
a. As applied to asbestos, consist of the very shortest of classified
grades; the fibers may vary from microscopical thin filaments to crude
bundles of fibers of appreciable thickness. Included may be particles of
nonfibrous serpentine ranging from a palpable powder to granules of
visible size. Sinclair, 7
b. The product that is retained on a specified screen in the screening of
a crushed or ground material. ASM, 1
c. In gold cyanidation, the oversize after the gold-rich zinc from the
precipitation boxes has been rubbed through. Pryor, 3
d. The shortage in production under a royalty lease. CTD
A section of land according to the U.S. Governmental Survey that contains
less than 640 acres. Williams
Colloquialism for weathering (or low-velocity layer) shot in seismic
prospecting. AGI
A 15-min time-weighted average exposure that should not be exceeded at any
time during a work day even if the 8-h time-weighted average is within the
threshold limit value. Abbrev: STEL. ACGIH, 2
a. The reverse of longwall, frequently used to mean the face of a room.
Zern
b. A method of mining in which comparatively small areas are worked
separately, as opposed to longwall; e.g., room and pillar. BCI
c. A length of coal face intermediate between a stall and a normal
longwall face. A shortwall face may be any length between about 5 yd and
30 yd (4.6 m and 27 m) and is generally employed in pillar methods of
working. Rooms and stables may also be classified as shortwall faces.
See also:shortwall development