A tetragonal mineral, 3NaAlSi3 O8 .NaCl ; scapolite group;
forms a series with meionite.
Trade name for a heavy track-mounted continuous miner for operation in
thick seams. The front end contains two cutter arms that rotate in
opposite directions to sweep the coal it cuts inwards toward the center.
The broken coal is taken back through the machine to a chain conveyor. Two
cutter chains are arranged at roof and floor level behind the arms to cut
down the coal left between the rotating arms. The machine cuts an area 12
ft (3.7 m) wide and 7 ft (2.1 m) high. Power is supplied by two motors,
one of 70 hp (52.2 kW) and the other of 25 hp (17.4 kW). It has a
continuous capacity from 3 to 3-1/2 st/min (2.7 to 3.2 t/min). This
machine has been subject to several modifications.
See also:continuous miner
Science that treats of the living organisms of the sea, the chemical and
physical characteristics of their environment, and factors affecting their
distribution. Hy
Used for investigating strata beneath the seabed and taking sample and
cores from which dredging conditions may be assessed. Hammond
A sedimentary deposit laid down in the sea, usually beyond the seaward
edge of the littoral belt. Stokes
Erosion by moving seawater, the action of which is largely intensified by
detritus carried by it. Schieferdecker
The marine science that treats of the topographical features of the sea
bottom, the phenomena that have developed it, and the types, processes,
and distribution of sedimentation. Hy
Organic matter deposited on the sea bottom. Tomkeieff
The spreading of the sea over a land area. AGI
The mining of marine mineral deposits, classified as unconsolidated
deposits such as gravel, mineral sands, or nodules; consolidated deposits
such as outcrops, veins, or crusts; and fluid that is seawater or
hydrothermal fluids; from, on, or beneath the seabed, whether on the
continental shelf or in the deep ocean basins. SME, 1
See:transgression
A chromian variety of phengite, a siliceous variety of muscovite.
Plants that grow naturally under salty conditions on a foreshore and that
may materially help to prevent scour and stabilize sand dunes.
Hammond
a. An easily recognized stratigraphic feature having characteristics
distinctive enough for it to serve as a reference or datum or to be
traceable over long distances, esp. in the subsurface, as in well drilling
or in a mine working; e.g., a stratigraphic unit readily identified, or
any recognizable rock surface such as an unconformity or a corrosion
surface. See also:format
marker formation. CF:horizon
b. A layer that yields characteristic reflections over a more or less
extensive area. AGI
c. A layer that accounts for a characteristic segment of a
seismic-refraction time-distance curve and can be followed over reasonably
extensive areas. AGI
d. S. Afr. See:outcrop
e. See:marker block
a. See:marker
b. A stratigraphic bed selected for use in preparing structural,
paleogeologic, and other maps that emphasize the nature or attitude of a
plane or a surface. It is generally selected for lithologic
characteristics, but biologic factors and unconformities may control.
Syn:indicator; key bed; marker horizon. See also:horizon; marker.
CF:indicator
A small block on which the footage below the collar of a borehole is
marked and inserted between pieces of core at its appropriate place in a
core box to indicate the depth in the borehole at which the core was
obtained. Also called footage block; footmark; marker. The marker block is
placed in the core box on completion of each drilled interval.
See also:marker
See:marker
See:marker bed; marker.
In silver refining, the pot at the end of the series of pots used in the
Pattinson process, in the direction in which the amount of silver left in
the lead is diminishing. It contains the market lead. Fay
Variety of petroleum found in Russia. Tomkeieff
a. An old term loosely applied to a variety of materials, most of which
occur as loose, earthy deposits consisting chiefly of an intimate mixture
of clay and calcium carbonate, formed under marine or esp. freshwater
conditions; specif. an earthy substance containing 35% to 65% clay and 65%
to 35% carbonate. Marl is usually gray; it is used esp. as a fertilizer
for acid soils deficient in lime. In the Coastal Plain area of
Southeastern United States, the term has been used for calcareous clays,
silts, and sands, esp. those containing glauconite (greensand marls); and
for newly formed deposits of shells mixed with clay. AGI
b. A soft, grayish to white, earthy or powdery, usually impure, calcium
carbonate precipitated on the bottoms of present-day freshwater lakes and
ponds, largely through the chemical action of aquatic plants, or forming
deposits that underlie marshes, swamps, and bogs that occupy the sites of
former (glacial) lakes. The calcium carbonate may range from 90% to less
than 30% . Syn:bog lime
c. A term occasionally used (as in Scotland) for a compact, impure,
argillaceous limestone. Etymol: French marle. AGI