a. The process of giving off oil or gas from pore spaces or fractures; it
can be observed in drill cores. AGI
b. The exudation of small amounts of water from coal or a stratum of some
other rock. AGI
Any face, such as the walls of a well or borehole or the sides of a
fracture, that traverses a reservoir rock or aquifer, permitting the
stored liquid or gas to seep (or to bleed) into the opening. AGI
A coal mining term used when feeders or blowers act as the means by which
gas is "bled off" or dissipated to the adjoining strata or to the surface.
Kentucky
a. Without specific qualification, it means zincblende or the sulfide of
zinc (sphalerite), which has the luster and often the color of common
resin and yields a white streak and powder. The darker varieties are
called blackjack by English miners. Other minerals having this luster are
also called blendes, such as antimony blende, ruby blende, pitchblende,
and hornblende. Sphalerite (blende) is often found in brown shining
crystals, hence its name among German miners, from the word blenden,
meaning to dazzle. Fay
b. A miners' term for sphalerite.
c. Various minerals, chiefly metal sulfides, with bright or resinous but
nonmetallic luster, e.g., zinc blende (sphalerite), antimony blende
(kermesite), bismuth blende (eulytite), cadmium blende (greenockite),
pitchblende (uraninite), hornblende.
An unconformity having no distinct surface of separation or sharp contact,
as at an erosion surface that was originally covered by a thick residual
soil, which graded downward into the underlying rocks and was partly
incorporated in the overlying rocks; e.g., a nonconformity between granite
and overlying basal arkosic sediments derived as a product of its
disintegration. Syn:graded unconformity
Mixing in predetermined and controlled quantities to give a uniform
product. BS, 5
A conveyor running beneath a line of ore bins or stockpiles, and so set
that each bin or stockpile can deliver onto the conveyor at a controllable
rate from individual feeders. Syn:paddle-type mixing conveyor;
screw-type mixing conveyor. Pryor, 3
a. To drill with the circulation medium (water or drill mud) escaping into
the sidewalls of the borehole and not overflowing the collar of the drill
hole. Long
b. An underground opening not connected with other workings nearby and at
about the same elevation. Long
c. Said of a mineral deposit that does not crop out. The term is more
appropriate for a deposit that terminates below the surface than for one
that is simply hidden by unconsolidated surficial debris.
Syn:blind vein
The near-surface end of a mineral deposit, e.g., the upper end of a seam
or vein that is truncated by an unconformity. Syn:buried outcrop
AGI
See:noncoring bit
In the underground gasification of coal, a borehole is drilled to a blind
end having no outside connection. A tube of smaller diameter is inserted
nearly the full length through which air is passed to supply a
gasification reaction at the far end of the hole. The hot gases return
around the outside of the tube. See also:underground gasification
Nelson
A horizontal passage, in a mine, not yet connected with the other
workings. See also:blind level
See:blende
A concealed brick header in the interior of a wall, not showing on the
faces. ACSG, 1
A borehole in which the circulating medium carrying the cuttings does not
return to the surface. Long
a. In leaching, reduced permeability of ion-exchange resins due to
adherent slimes. In sieving, blocking of screen apertures by particles.
Pryor, 3
b. A matting of, or stoppage by, fine materials during screening that
interferes with or blinds the screen mesh.
c. Compacting soil immediately over a tile drain to reduce its tendency to
move into the tile. Nichols, 1
In apparently massive rock that is being quarried, a plane of potential
fracture along which the rock may break during excavation. AGI
A vein having no outcrop. See also:blind lode; blind vein; lead.
a. One not yet holed through to connect with other passages.
Syn:blind drift
b. A cul-de-sac or dead end. Pryor, 3
c. A level for drainage, having a shaft at either end, and acting as an
inverted siphon.
A lode showing no surface outcrop, and one that cannot be found by any
surface indications. See also:blind lead; blind vein.
Mid. Any underground roadway not in use, having stoppings placed across
it. Syn:blind way