15. RESTS
(c) Sandbag
The Rear Sandbag shall be a bag or combination of bags, containing sand only...........
Looks like sand has many definitions & interpretations.....
The last entry specifically mentions
ilmenite.
http://www.merriam-webster.com/dictionary/sand
Main Entry: 1 sand Pronunciation: \ˈsand\ Function:
noun Etymology: Middle English, from Old English; akin to Old High German
sant sand, Latin
sabulum, Greek
psammos Date: before 12th century 1 a
: a loose granular material that results from the disintegration of rocks, consists of particles smaller than gravel but coarser than silt, and is used in mortar, glass, abrasives, and foundry molds b
: soil containing 85 percent or more of sand and a maximum of 10 percent of clay ;
broadly : sandy soil2 a
: a tract of sand
: beach b
: a sandbank or sandbar3
: the sand in an hourglass ;
also : the moments of a lifetime —usually used in plural <the
sands of this government run out very rapidly — H. J. Laski>4
: an oil-producing formation of sandstone or unconsolidated sand5
: firm resolution6
: a yellowish-gray color
http://www.answers.com/topic/sand
Sand is a loose, fragmented, naturally-occurring material consisting of very small particles of decomposed rocks, corals, or shells. Sand is used to provide bulk, strength, and other properties to construction materials like
asphalt and concrete. It is also used as a decorative material in landscaping. Specific types of sand are used in the manufacture of glass and as a molding material for metal casting. Other sand is used as an
abrasive in
sandblasting and to make
sandpaper.
The most common sand is composed of particles of
quartz and
feldspar. Quartz sand particles are
colorless or slightly pink, while feldspar sand has a pink or amber color. Black sands, such as those found in Hawaii, are composed of particles of
obsidian formed by volcanic activity. Other black sands include materials such as
magnetite and homblende. Coral sands are white or gray, and sands composed of broken shell fragments are usually light brown. The white sands on the Gulf of Mexico are made of smooth particles of limestone known as
oolite, derived from the Greek word meaning egg stone. The white sands of White Sands, New Mexico, are made of
gypsum crystals. Ordinarily, gypsum is dissolved by rain water, but the area around White Sands is so
arid that the crystals survive to form
undulating dunes.
Quartz sands, which are high in
silica content, are used to make glass. When quartz sands are crushed they produce particles with sharp, angular edges that are sometimes used to make sandpaper for smoothing wood. Some quartz sand is found in the form of sandstone. Sandstone is a sedimentary, rock-like material formed under pressure and composed of sand particles held together by a cementing material such as calcium carbonate. A few sandstones are composed of almost pure quartz particles and are the source of the silicon used to make
semiconductor silicon chips for microprocessors.
Molding sands, or foundry sands, are used for metal casting. They are composed of about 80%-92% silica, up to 15%
alumina, and
2% iron oxide. The alumina content gives the
molding sand the proper binding properties required to hold the shape of the mold cavity.
Sand that is scooped up from the bank of a river and is not washed or sorted in any way is known as bank-run sand. It is used in general construction and landscaping.
The definition of the size of sand particles varies, but in general sand contains particles measuring about 0.0025-0.08 in (0.063-2.0 mm) in diameter. Particles smaller than this are classified as
silt. Larger particles are either granules or gravel, depending on their size. In the construction business, all aggregate materials with particles smaller than 0.25 in (6.4 mm) are classified as fine
aggregates. This includes sand. Materials with particles from 0.25 in (6.4 mm) up to about 6.0 in (15.2 cm) are classified as coarse aggregates.
Sand has a density of 2,600-3,100 lb per cubic yard (1,538-1,842 kg per cubic meter). The trapped water content between the sand particles can cause the density to vary substantially.
Sci-Tech Encyclopedia: Sand
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Unconsolidated granular material consisting of mineral, rock, or biological fragments between 63 micrometers and 2 mm in diameter. Finer material is referred to as
silt and clay;
coarser material is known as
gravel. Sand is usually produced primarily by the chemical or mechanical breakdown of older source rocks, but may also be formed by the direct chemical
precipitation of mineral grains or by biological processes. Accumulations of sand result from hydrodynamic sorting of
sediment during transport and deposition.
See also Clay minerals;
Depositional systems and environments;
Gravel;
Mineral;
Rock;
Sedimentary rocks.
Most sand originates from the chemical and mechanical breakdown, or weathering, of
bedrock. Since chemical weathering is most efficient in soils, most sand grains originate within soils. Rocks may also be broken into sand-size fragments by mechanical processes, including
diurnal temperature changes, freeze-thaw cycles,
wedging by salt crystals or plant roots, and ice
gouging beneath glaciers.
See also Weathering processes.
Because sand is largely a
residual product left behind by incomplete chemical and mechanical weathering, it is usually
enriched in minerals that are resistant to these processes. Quartz not only is extremely resistant to chemical and mechanical weathering but is also one of the most abundant minerals in the Earth's
crust. Many sands dominantly consist of
quartz. Other common constituents include
feldspar, and fragments of
igneous or
metamorphic rock. Direct chemical precipitation or hydrodynamic processes can result in sand that consists almost entirely of
calcite, glauconite, or dense dark-colored minerals such as
magnetite and
ilmenite.
See also Feldspar;
Quartz.
Although sand and gravel has one of the lowest average per
ton values of all mineral commodities, the vast demand makes it among the most economically important of all mineral resources. Sand and gravel is used primarily for construction purposes, mostly as concrete
aggregate. Pure quartz sand is used in the production of glass, and some sand is enriched in rare commodities such as ilmenite (a source of
titanium) and in gold.
See also Concrete
