a. Any geologic event that produces sudden and extensive changes in the
Earth's surface; e.g., an exceptionally violent earthquake.
Syn:cataclysmic; cataclysmal. AGI
b. Any violent, overwhelming flood that spreads over the land; a deluge.
AGI
See:cataclysm
See:cataclysm
Acceleration or deceleration of a chemical reaction produced by a
substance that is unchanged by the reaction.
A substance capable of changing the rate of a reaction without itself
undergoing any net change. AGI
A combustible-gases detector depending upon the combustion or oxidation of
methane at heated filaments. Usually the gas is drawn through the
apparatus by a rubber suction bulb, and the filaments are heated by a
battery in the instrument. A version of this principle is the resistance
methanometer. Nelson
A process that converts the incompletely burned hydrocarbons present in
fuel exhaust into harmless gases. It involves burning up the fuel remnants
with the aid of catalysts-- chemical agents, such as platinum and
palladium, that speed up reactions without being consumed themselves.
Movement of charged particles in a fluid medium in response to an electric
field. Metallic hydroxides and other positive sols migrate to the cathode
and negatives ones to the anode. See also:electrophoresis
Pryor, 3
A hexagonal mineral, Na2 ZrSi3 O9 .2H2 O ;
yellow to yellow-brown; forms thin, tabular hexagonal prisms.
An obsolete term for an iron meteorite remarkable for a high proportion of
nickel.
In geology, a sudden, violent change in the physical conditions of the
Earth's surface; a cataclysm. Standard, 2
a. Projection in a mine shaft that arrests a cage, skip, or other
reciprocating system in the event of fracture or overwind.
Pryor, 3
b. One of the catches or rests placed on shaft timbers, to hold the cage
when it is brought to rest at the top, bottom, or any intermediate
landing. See also:chair; dog; wing; rests. Fay
c. In coal work, a device for holding trams in a cage when hoisting.
See also:jack catch
d. One of the stops fitted on a cage to prevent cars from running off.
Fay
See:core lifter
An appliance fixed in the headgear to limit the drop of a cage after an
overwind. The upward speed and momentum of the loaded cage (after its
release from the rope) may be such that its subsequent drop is so severe
as to fracture the suspension gear, resulting in the cage falling down the
shaft. The amount of drop is limited by the catch gear, which consists of
a series of catches suspended from beams supported on hydropneumatic
buffers to reduce the impact shock. The cage is released by raising it
slightly and retracting the catches. See also:detaching hook; overwind.
Nelson
a. The recharge area and all areas that contribute water to it.
AGI
b. An area paved or otherwise waterproofed to provide a water supply for a
storage reservoir. See also:drainage basin
AGI
a. In mineral processing, a sump in a mill to which the floor slopes
gently, and into which all spillage gravitates or is hosed either for
return by pumping to its place in the flowline or for periodical removal.
Also called catch sump. Pryor, 3
b. See:sump; tailing pit.
a. One of a set of spring-loaded points in an upgrade railway line that
close behind a rising train. If any rolling stock breaks away it is then
automatically diverted to a siding. Pryor, 3
b. Position of intersection of a road cut or fell with natural ground;
usually marked with a stake.
Prop erected in the face to act as a temporary support until permanent
supports are brought forward. Also called watch prop; safety prop.
Nelson; CTD
Eng. A platform in a shaft a few feet beneath a working scaffold; to be
used in case of accident.
A surface drain to intercept and collect the flow of water from adjoining
land, so as to prevent it from reaching a road or mine sidings.
See also:subsoil drainage
A miner's term applied locally in Illinois to a bed of marcasite from 2 to
6 in (5.08 to 15.24 cm) thick that sometimes occurs between the "clod"
roof of a coal seam and the more stratified shale above. The lower surface
of the marcasite bed is characterized by very irregular protuberances
extending downward 1 to 3 in (2.54 to 7.62 cm) into the clod. Also called
cat. AGI