Those in which air is supplied direct to a rotary agitator, mechanically
driven, situated at depth in the flotation cell so that air is churned
with ore pulp. Two types are (1) that in which air is drawn down by
impeller; and (2) that in which low-pressure air is blown in.
Syn:subaeration cells
a. A group term applied to rocks of the tholeiitic and calc-alkaline
series. AGI
b. Said of an igneous rock that contains no alkali minerals other than
feldspars. AGI
c. Used to describe an igneous rock of the Pacific suite. AGI
Somewhat angular, free from sharp angles but not smoothly rounded; specif.
said of a sedimentary particle showing definite effects of slight
abrasion, retaining its original general form, and having faces that are
virtually untouched and edges and corners that are rounded off to some
extent. AGI
Said of conditions and processes, or of features and deposits, that exist
or are situated in or under water, esp. freshwater, as in a lake or
stream. CF:subaerial
A mine waste management practice whereby mill tailings or mine waste rock
are emplaced under a body of water to minimize sulfide oxidation and acid
formation, and eliminate airborne particulate pollution. If a natural
sedimentation basin is utilized, erosion hazards inherent to subaerial
impoundments are eliminated.
Surface mining in which the material mined is removed from the bed of a
natural body of water. AIME, 2
See:semiarid
A sandstone that does not have enough feldspar to be classed as an arkose,
or a sandstone that is intermediate in composition between arkose and pure
quartz sandstone. CF:arkose
Noise the intensity of which is so low that it can only be detected by
means of a microphone and suitable amplifying equipment. How these
subaudible noises, or microseisms, originate has not definitely been
established, but it is believed that they are produced by incipient
cracking or intermovement between fragments of crystalline aggregates in
the rock. It has been found that almost invariably a period of increased
microseismic activity precedes any large-scale ground movement or failure.
Issacson
a. A layer of material laid on the natural ground under a road base for
purposes of strengthening. CF:subgrade
b. The lowest part of a base. Crispin
The rank of coal, within the subbituminous class of Classification D 388,
such that, on the moist, mineral-matter-free basis, the gross calorific
value of the coal in British thermal units per pound is equal to greater
than 10,500 (24.42 MJ/kg) but less than 11,500 (26.75 MJ/kg) and the coal
is nonagglomerating. ASTM
The rank of coal, within the subbituminous class of Classification D 388,
such that, on the moist, mineral-matter-free basis, the gross calorific
value of the coal in British thermal units per pound is equal to greater
than 9,500 (22.10 MJ/kg) but less than 10,500 (24.42 MJ/kg) and the coal
is nonagglomerating. ASTM
The rank of coal, within the subbituminous class of Classification D 388,
such that, on the moist mineral-matter-free basis, the gross calorific
value of the coal in British thermal units per pound is greater than 8,300
(19.31 MJ/kg) but less than 9,500 (22.10 MJ/kg), and the coal is
nonagglomerating. ASTM
a. Black lignite or lignitic coal. Fay
b. Coal of rank intermediate between lignite and bituminous. In the
specifications adopted jointly by the American Society for Testing and
Materials (D388-38) and the American Standards Association (M20.1-1938),
subbituminous coals are those with calorific values in the range 8,300 to
13,000 Btu (19.3 to 30.2 MJ/kg), calculated on a moist,
mineral-matter-free basis, which are both weathering and nonagglomerating
according to criteria in the classification. Stokes
Partially or indistinctly conchoidal. Webster 3rd
Cooling of a liquid refrigerant below the condensing temperature at
constant pressure. Strock, 2
subcritical area of extraction
An area of goaf too small to cause full subsidence at the surface.
See also:critical area of extraction
See:group level
See:sublevel caving
See:top slicing combined with ore caving
See:underdrilling