The fractured ground within the fracture zone. CF:extradosal
Lewis
a. Formed within a geologic formation, more or less contemporaneously with
the enclosing sediments. The term is esp. used in regard to
syndepositional folding or slumping; e.g., intraformational deformation or
intraformational breccia. AGI
b. Existing within a formation, with no necessary connotation of time of
origin. CF:interformational
A rock formed by brecciation of partly consolidated material, followed by
practically contemporaneous sedimentation. It is similar in nature and
origin to an intraformational conglomerate, but contains fragments showing
greater angularity. AGI
a. A conglomerate in which the clasts are essentially contemporaneous with
the matrix, developed by the breaking up and rounding of fragments of a
newly formed or partly consolidated sediment (usually shale or limestone)
and their nearly immediate incorporation in new sedimentary deposits;
e.g., an edgewise conglomerate. AGI
b. A conglomerate occurring in the midst of a geologic formation, such as
one formed during a brief interruption in the orderly deposition of
strata. It may contain clasts external to the formation. The term is used
in this sense esp. in England. AGI
Intricate and complicated folding, resulting from the subaqueous slumping
or sliding of unconsolidated sediments under the influence of gravity.
AGI
a. Said of a phenocryst, of an earlier generation than its groundmass,
that formed at depth, prior to extrusion of a magma as lava. AGI
b. Said of the period of crystallization occurring deep within the Earth
just prior to the extrusion of a magma as lava. AGI
c. Located, formed, or originating deep within the Earth. AGI
Apparatus that is so constructed that, when installed and operated under
the conditions specified by the certifying authority, any electrical
sparking that may occur in normal working, either in the apparatus or in
the circuit associated therewith, is incapable of causing an ignition of
the prescribed flammable gas or vapor. BS, 13
A circuit in which any electrical sparking that may occur in normal
working under the conditions specified by the certifying authority, and
with the prescribed components, is incapable of causing an ignition of the
prescribed flammable gas or vapor. BS, 13
A machine that is safe in itself, without having to be placed inside a
flameproof enclosure. It implies that the machine cannot produce any spark
that is capable of igniting mixtures of combustible gases and air in
mines. Nelson
In a circuit, safety such that any sparking that may occur in that circuit
in normal working, or in reasonable fault conditions, is incapable of
causing an explosion of the prescribed inflammable gas. NCB
In casing a borehole, the highest and first column that is inserted.
Stoces
a. In geology, a mass of igneous rock that, while molten, was forced into
or between other rocks. Fay
b. A mass of sedimentary rock occurring in a coal seam. BS, 11
See:contact breccia
Faulting coincident with the intrusion of an igneous rock.
A method of placing concrete by intruding the mortar component in
position; it is then converted to concrete by intruding the mortar
component into its voids. One of the chief advantages of the method is
that it permits the placing of concrete underwater. Carson, 2
Of or pertaining to intrusion--both the processes and the rock so formed.
n. An intrusive rock. CF:extrusive
An igneous intrusion resembling a sheet, apparently formed from a magma
rich in volatiles. AGI
The property of some silicate minerals (e.g., stilbite, vermiculite,
scapolite) or rocks (e.g., perlite) to expand permanently when heated to
form an irregular or vesicular structure. CF:exfoliation
An inrush of water, on a large scale, that floods the entire mine or a
large section of the workings. See also:tapping old workings
Nelson
An alloy of nickel and iron, containing about 36% nickel, and having an
extremely low coefficient of thermal expansion. It is used in the
construction of surveying instruments, such as pendulums, level rods,
first-order leveling instruments, and tapes. AGI
a. Mex. A mining trespass. Fay
b. See:transgression