See:middlings
A brown, resinous, brittle mineral found between layers of coal at the
Middleton collieries, near Leeds, England, and also at Newcastle.
Fay
a. That part of the product of a washery, concentration, or preparation
plant that is neither clean mineral product nor reject (tailings). It
consists of fragments of coal ore mineral and gangue. The material is
often sent back for crushing and/or retreatment. Syn:middles
Nelson
b. In two-component ore, particles incompletely liberated by comminution
into concentrate or gangue. In complex ores, in addition to incomplete
liberation, there may be multiphased particles of middling or intermediate
species that react too feebly to treatment to report as concentrate or
tailing. Pryor, 2
An elevator that removes material for further treatment or for disposal as
an inferior product. BS, 5
Scot. The middle one of three landing places in a shaft. Fay
In mining, a support to the center of a tunnel. Standard, 2
N. of Eng. Lamp (not safety) carried by trammers, etc. Fay
Moss agate with inclusions resembling a swarm of mosquitoes. Also called
gnat stone; mosquito agate.
A dust-sampling apparatus almost identical in principle and design with
the regular Greenburg-Smith impinger, the main difference being its
smaller size and the fact that only a 12-in (30.5-cm) head of water is
required for its operation. See also:Greenburg-Smith impinger
A continuous, seismic, median mountain range extending through the North
and South Atlantic Oceans, the Indian Ocean, and the South Pacific Ocean.
It is a broad, fractured swell with a central rift valley and usually
extremely rugged topography; it is 1 to 3 km in elevation, about 1,500 km
in width, and over 84,000 km in length. According to the hypothesis of
sea-floor spreading, the mid-ocean ridge is the source of new crustal
material. See also:rift valley
AGI
See:rift valley
See:mid-ocean ridge
a. Scot. Mine workings above or below in the same mine or colliery.
Fay
b. See:middoor
A variety of dolomite from Miemo, Tuscany, Italy.
An isometric mineral, (Ag,Cu)I ; canary yellow.
A brown variety of pyromorphite containing calcium from Mies, Czech
Republic.
Mobile, or potentially mobile, mixture of solid rock material(s) and
magma, the magma having been injected into or melted out of the rock
material. Etymol: Greek, mixture. AGI
A composite rock composed of igneous or igneous-appearing and/or
metamorphic materials that are generally distinguishable megascopically.
See also:composite gneiss
AGI
Formation of a migmatite. The more mobile, typically light-colored, part
of a migmatite may be formed as the result of anatexis, lateral secretion,
metasomatism, or injection. AGI
a. The movement of oil, gas, or water through porous and permeable rock.
Parallel (longitudinal) migration is movement parallel to the bedding
plane. Transverse migration is movement across the bedding plane.
AGI
b. The process by which events on a reflection seismogram are mapped in an
approximation of their true spatial positions. It requires knowledge of
the velocity distribution along the raypath. Also, the seismic correction
that is applied. AGI; Schieferdecker
c. The movement of a topographic feature from one locality to another by
the operation of natural forces; specif. the movement of a dune by the
continual transfer of sand from its windward to its leeward side.
AGI
d. The slow downstream movement of a system of meanders, accompanied by
enlargement of the curves and widening of the meander belt. AGI
e. A broad term applied to the movements of plants and animals from one
place to another over long periods of time. AGI
The movement or seepage of oil through rocks wherever they are
sufficiently permeable to allow such passage; of considerable importance
in oil geology. Nelson