See:silicon borides
Soil or sediment removed from a site for use in construction, such as
sandy sediment dredged and pumped to restore an eroded beach, or clay
taken to build a levee or dike. Army Corps of Eng.
a. The source of material taken from some location near an embankment
where there is insufficient excavated material nearby on the job to form
the embankment. Borrow-pit excavation is therefore a special
classification, usually bid upon as a special item in contracts. It
frequently involves the cost of land or a royalty for material taken from
the land where the borrow pit is located; it also often requires the
construction of a suitable road to the pit. This type of excavation
therefore usually runs higher in cost than ordinary excavation.
Hess
b. An excavated area where borrow has been obtained. AGI
a. Diamond material unsuitable for gems because of its shape, size, or
color and because of flaws or inclusions. It also occurs in finely
crystalline aggregates and is usually crushed into finer material.
Syn:boart; bortz; boort; boartz; borts; bowr. See also:shot bort
b. Inferior, coarsely crystalline diamonds, many of which contain black
carbon or other minerals; used for core drilling, cutting, and polishing
hard materials.
c. Formerly used to mean the Brazilian carbonado or black diamond.
Hess
d. Industrial diamond. ASM, 1
e. Very hard, flawed or discolored diamonds used in drilling and glass
cutting. Gordon
f. S. Afr. Rounded forms of diamond with rough exterior and radiated or
confused crystalline structure, but hardness equal to that of diamond.
Beerman
g. Originally the term was used as a name for all crystalline diamonds not
usable as gems; later it was used to designate those diamonds not usable
as gems or toolstones. Currently the term is applied to low-grade
industrial diamonds suitable only for use in a fragmented form.
h. A granular to very finely crystalline aggregate consisting of
imperfectly crystallized diamonds or of fragments produced in cutting
diamonds. It often occurs as spherical forms, with no distinct cleavage,
and having a radial fibrous structure. AGI
i. A diamond of the lowest quality, so flawed, imperfectly crystallized,
or off-color that it is suitable only for crushing into abrasive powders
for industrial purposes (as for saws and drill bits); an industrial
diamond. Originally, any crystalline diamond (and later, any diamond) not
usable as a gem. AGI
j. A term formerly used as a syn. of carbonado. CF:ballas
Syn:magnetic bort
See:diamond bit
See:bort
See:diamond bit
See:bort
a. The section of a blast furnace extending upward from the tuyeres to the
plane of maximum diameter. ASM, 1
b. A lining of quartz that builds up during the smelting of copper ores
and thus decreases the diameter of the furnace at the tuyeres.
ASM, 1
c. A trough in which bloomery tools (or in copper smelting, hot ingots)
are cooled. Fay
A water jacket used for cooling the walls of a shaft furnace. Fay
A water tank that receives newly cast copper shapes for rapid cooling.
Pryor, 3
a. Arkansas. A coal mine employee not under the jurisdiction of the
miner's union. Fay
b. A proturberant and often dome-shaped mass of igneous rock congealed
beneath the surface of the Earth and laid bare by erosion.
Webster 3rd
c. An igneous intrusion that is less than 40 mi2 (104 km (super
2) ) in surface exposure and is roughly circular in plan. CF:stock
AGI
Scot. The holing or undercutting of a thick seam, as of limestone, the
height of the undercutting being sufficient for a person to work in.
Modification of the pan-amalgamation process; ore slurry flows
continuously through a series of pans and settling tanks. Bennett
A light-colored hypabyssal rock, characterized by bostonitic texture and
composed chiefly of alkali feldspar; a fine-grained trachyte with few or
no mafic components. The name is derived from Boston, MA, for no clear
reason. Not recommended usage. AGI
Said of the texture of bostonite, in which microlites of rough irregular
feldspar tend to form clusters of divergent laths within a trachytoid
groundmass. AGI
An early name for prehnite.
A monoclinic mineral, Cu2 Cl(OH)3 ; trimorphous with
atacamite and paratacamite.
A local increase above the normal variation in the chemical composition,
distribution, ecological assemblage, or morphology of plants, indicating
the possible presence of an ore deposit or anthropomorphic contamination.
See also:geobotanical prospecting
Prospecting in which differences in plant growth or plant family serve as
a clue to the presence of metals beneath barren rock or a covering of sand
and gravel. Pearl
A monoclinic mineral, MgFe3+ (SO4 )2 (OH).7H (sub
2) O ; reniform, botryoidal, or globular; hyacinth-red to orange; in
secondary sulfate deposits capping sulfide ore deposits.
Syn:red iron vitriol