a. A door to separate the air in an intake airway from that in a return
airway and prevent leakage. It is normally constructed with
tongued-and-grooved boards secured by battens, and it is built into brick
or concrete walls to form an airtight closure of the airway. Separation
doors are usually arranged in twos or threes several yards apart, to
reduce leakage when workers or cars are passing along the roadway.
See also:bearing door; steel separation door; ventilation doors.
Nelson
b. See:air door
A general term indicating the effective size at which separation has taken
place, calculated from a size analysis of the product; commonly expressed
as either partition size or equal errors size. BS, 5
Eng. A massive cast-iron plate suspended from the roof of a return airway,
through which all the return air of a separate district flows, allowing
the air to always flow past or underneath it; but in the event of an
explosion of gas, the force of the blast closes it against its frame or
seating, and prevents a communication with other districts.
a. A machine for separating, with the aid of water, suspensions, or air,
materials of different specific gravity. Strictly, a separator parts two
or more ingredients, both valuable, while a concentrator saves but one and
rejects the rest; but the terms are often used interchangeably.
b. Any machine for separating materials, such as the magnetic separator
for separating magnetic materials from gangue. CF:concentrator
c. A screen, esp. a revolving screen, for separating things like stones or
coal into sizes. Standard, 2
A monoclinic mineral, Mg4 Si6 O15 (OH)2 .6H
2 O ; soft; sp gr, 2 but fibrous dry masses float on water;
occurs in veins in calcite and in alluvial deposits formed from weathering
of serpentine masses, chiefly in Asia Minor, as meerschaum; may be used in
making pipes, ornamental carvings. Syn:meerschaum; sea-foam.
Plural of septarium.
Said of the irregular polygonal pattern of internal cracks developed in
septaria, closely resembling the desiccation structure of mud cracks; also
said of the epigenetic mineral deposits that may occur as fillings of
these cracks. AGI
See:septarium
See:septarium
a. A large, roughly spheroidal concretion, 8 to 90 cm in diameter, usually
of an impure argillaceous carbonate, such as clay ironstone. It is
characterized internally by irregular polyhedral blocks formed by a series
of radiating cracks that widen toward the center and that intersect a
series of cracks concentric with the margins; these cracks are invariably
filled or partly filled by crystalline minerals (most commonly calcite)
that cement the blocks together. Its origin involves the formation of an
aluminous gel, case hardening of the exterior, shrinkage cracking due to
dehydration of the colloidal mass in the interior, and vein filling. The
veins sometimes weather in relief, thus producing a septate pattern.
Syn:septarian nodule; septarian concretion; beetle stone; turtle stone.
AGI
b. A crystal-lined crack or fissure in a septarium. Pl: septaria.
AGI
An alternate name for serpentine minerals reflecting their 7Aa basal
spacing and chloritelike formulae.
Membrane separating two phases, for example, pulp and filtrate.
Pryor, 3
A method of control whereby, once action has been initiated, a number of
electrical circuits will automatically function in a prescribed order.
BS, 13
An interlock provided between a number of manually controlled electrical
circuits, which are required to function in a prescribed order, and which
prevents a circuit from being operated unless the preceding circuit has
completed its part in the sequence. BS, 13
An arrangement whereby the starting of one belt conveyor starts all of its
feeder conveyors in a predetermined manner. The purpose of sequence
starting is to prevent spilling at transfer points and to reduce the power
demand in starting the system. See also:power sequence; pilot sequence.
NEMA, 2
A sequestering agent forms soluble complex ions with a simple ion, thereby
inhibiting the activity of that ion. Lowenheim
A triclinic mineral, Na(Mn,Ca)2 Si3 O8 (OH) , with Mn
replaced by Ca toward pectolite; pink.
A triclinic mineral, Ca2 (Mg,Al)6 (Si,Al,B)6 O (sub
20) ; aenigmatite group; blue.
Samples collected according to some predetermined plan, such as along the
intersections of gridlines, or at stated distances or times. The method is
used to ensure random sampling. AGI
Said of the texture of an igneous rock, typically porphyritic, in which
the sizes of the grains vary gradually or in a continuous series.
CF:hiatal
A white, fine-grained potassium mica occurring in small scales as an
alteration product of various aluminosilicate minerals, having a silky
luster, and found in various metamorphic rocks (esp. in schists and
phyllites) or in the wall rocks, fault gouge, and vein fillings of many
ore deposits. It is commonly muscovite or very close to muscovite in
composition, but may also include paragonite and illite.
See also:muscovite