Powder so composed as to ignite by a slight percussion; fulminating
powder. Fay
An apparatus in which material is sorted according to size. It consists
essentially of superimposed, oppositely inclined sieves, both mechanically
agitated by vertical lever and having water sluices.
Applicable to drill machines and/or the methods used to drill boreholes by
the chipping action of impacts delivered to a chisel-edged bit.
See also:churn drill; percussion drill. Long
Early form of shaking table. See also:concussion table; shaking table.
Pryor, 3
A system of boring using solid or hollow rods or ropes; may be used for
exploratory drilling and for blasting purposes. See also:boring
Nelson
A pneumatic drill that is used widely in mining for exploration and for
blasting purposes. See also:rock drill
a. A method of drilling whereby repeated blows are applied by the bit,
which is repositioned by intermittent rotation. BS, 12
b. A form of drilling in which the rock is penetrated by the repeated
impact of a reciprocating drill tool. Fraenkel
Any of several types of machine, including heading machines, air picks,
and the numerous types of percussive drills. Mason
In the so-called perfect-discharge elevator, there is an extra set of
traction or sprocket wheels on the discharge side, so set that they bend
the chains back under the head wheels. As a consequence, the discharging
chute may be placed directly under the buckets. This elevator will also
handle material that packs, and both types of gravity-discharge elevators
may be run much slower than the centrifugal type. Pit and Quarry
A structural frame that is stable under loads imposed upon it from any
direction, but which would become unstable if one of its members were
removed or one of its fixed ends became hinged. Hammond
Any curve used to show the relationship between properties of coal and
results of a specific treatment. BS, 5
Maceral having a high hydrogen content, such as exinite and resinite.
Tomkeieff
A prefix meaning around or beyond. AGI
A kind of provitrain in which the cellular structure is derived from
cortical material. CF:suberain; xylain. AGI
a. The micropetrological constituent, or marceral, of periblain. It
consists of cortical tissue almost jellified in bulk, but still showing
indications of cell structure under a microscope. AGI
b. A distinction of telinite based on botanical origin (cortical tissue).
CF:suberinite
a. An isometric mineral, MgO; cubic cleavage; colorless to yellow or
brown; may be strongly colored by inclusions; occurs in high-temperature
metamorphic rocks derived from dolomite. Syn:periclasite
b. The mineral group bunsenite, manganosite, monteponite, periclase, and
wuestite.
See:periclase
Said of strata and structures that dip radially outward from, or inward
toward, a center, to form a dome or a basin. CF:quaquaversal;
centroclinal. AGI
a. A general term for a fold in which the dip of the beds has a central
orientation; beds dipping away from a center form a dome, and beds dipping
toward a center form a basin. The term is generally British in usage.
See also:centrocline; dome; quaquaversal. AGI
b. A variety of albite elongated in the direction of the b-axis and often
twinned with this as the twinning axis. It occurs in veins as large
milky-white opaque crystals. Pericline is probably an albitized
oligoclase. AGI
A twin crystal, in the monoclinic system, whose twinning axis is the
orthoaxis of the crystal. Fay
a. A transparent to translucent green gem variety of forsterite in the
olivine group. Also spelled peridote. Syn:bastard emerald
b. A yellowish-green or greenish-yellow variety of tourmaline, approaching
olivine in color. It is used as a semiprecious stone. See also:olivine