a. Boreholes that are loaded and fired for the purpose of relieving or
removing part of the burden of the charge to be fired in the main blast.
b. Holes drilled closely along a line, that are not loaded, and that serve
to weaken the rock so that it will break along that line.
Syn:trim holes
c. Singular. A port or passageway through which the core, as it advances
into the inner tube of a double-tube core barrel, forces water out of the
inner tube to the outside of the barrel through the innertube head.
Long
d. Singular. A borehole drilled ahead of underground openings to tap and
drain a water-bearing formation. Also called cover hole; pilot hole.
Long
Indigenous limonite that is porous and cavernous in texture, commonly
botryoidal after chalcocite. CF:indigenous limonite
A map representing topographic relief of an area by contour lines,
hachures, hill shading, coloring, or similar graphic means.
A valve that will allow air or fluid to escape if its pressure becomes
higher than the valve setting. Also called pressure relief valve.
Nichols, 1
A borehole that is drilled at the toe of an earth dam as a relief for any
high water pressure caused by the weight of the dam. Hammond
In a round of shots planned for sequential firing when shaft sinking or
tunneling, holes fired after cut holes and before lifters and slippers.
Pryor, 3
A loading deck for lorries on the land side of a retaining wall
contructed, for example, as a jetty of steel sheet piling, the relieving
platform being supported as a rule partly by the wall and partly by
bearing piles. See also:surcharge
A shot fired to dislodge or expose a misfire. BS, 12
A locked spirit-burning lamp fitted with an internal relighting device.
BS, 8
A place in a mine at which safety lamps can be relighted under controlled
conditions. BS, 13
Magnetic quality analogous to resistance in the flow of electric current.
Pryor, 3
Residual magnetism in a ferromagnetic substance (its hysteresis) after
removal of an external magnetizing force. Pryor, 3
a. Part of the magnetization of a body that does not disappear when the
external magnetic field disappears. Schieferdecker
b. That component of a rock's magnetization that has a fixed direction
relative to the rock and is independent of moderate, applied magnetic
fields such as the Earth's magnetic field. CF:induced magnetization
See also:hysteresis
When a block of ground is stoped in such a way that at some time its
remainder is surrounded on all sides by stoped ground, that remainder is
termed a remnant. Spalding
Soil that has had its natural structure modified by manipulation.
ASCE
Disturbance of the interval structure of clay or silt; when remolded, such
material will lack shearing strength and gain compressibility. In
consequence, driven piles are not recommended in certain clays.
See also:thixotropic fluid
The ratio of the modulus of deformation of a soil in the undisturbed state
to the modulus of deformation of the soil in the remolded state.
ASCE
The ratio of the unconfined compressive strength of an undisturbed
specimen of soil to the unconfined compressive strength of a specimen of
the same soil after remolding at unaltered water content. Also called
sensitivity ratio. ASCE
See:atacamite
a. The control of plant operation by personnel or computers housed under
conditions that can be remote, safe, and convenient. This is a feature of
both electrical and electronic automatic control. In the control room,
various plants can be started up by pushbutton and the governing
conditions can be set. Instrumentation records all relevant data; it also
gives warning of unsafe conditions and shuts down the plant if no
correction is made. Changeover switches can introduce different operations
and sequences in the working of the plant. Indicating lights can show what
plant is working and the progress made. Fault indication can show the
reason in the event of a shutdown. Also called centralized control.
Nelson
b. A term applied to a switch, circuit breaker, starter, or similar
apparatus, to denote that its operation can be controlled manually, from a
distance, by electrical or other means. BS, 13
A self-advancing support system in which the chocks and/or props are
advanced and reset on a longwall face from a point in the gate road
leading to the face. Hydraulic pressure and valves are commonly employed
and the system is largely in the experimental stage.
See also:pushbutton coal mining