The samples of the rocks obtained during boring. The diamond and shot
drill yield cores, while percussive drills yield sludge and chippings,
which are examined to determine the nature of the rocks passed through.
Borehole samples may also be required during site investigations.
See also:exploratory drilling; soil core. Nelson
The complete filling of a borehole with cement to prevent the entry of
water into mine workings. Nelson
The distance between boreholes drilled for exploration or sampling
purposes. With bedded minerals, the holes may be positioned at the
intersection points of coordinates or at the corners of equilateral
triangles with sides from 30 to 200 m apart. The spacing is closer with
patchy deposits. With metallic ores following belts across country, the
holes are spaced along lines crossing the orebody in order to yield cross
sections of the ore at definite intervals. In the case of known and
semiproved coalfields, boreholes at 1/2- to 1-km intervals may suffice.
Nelson
a. The process of determining the course of, and the target point reached
by, a borehole, using one of several different azimuth and dip recording
apparatuses small enough to be lowered into a borehole; also, the record
of the information thereby obtained. Also called drillhole survey;
directional survey. Long
b. The process of determining the mineralogical, structural, or physical
characteristics of the formations penetrated by a borehole using
geophysical logging apparatus small enough to be lowered into a borehole;
also, the record of the information thereby obtained. Long
c. See:well log
Instrumental tests to determine the amount and direction of deflection of
a borehole from vertical and horizontal planes. The instrument is lowered
into the hole and tested at intervals of depth. The data obtained may be
used to construct a scale model showing the actual course taken by the
hole. Nelson
a. Eng. Mud or fine cuttings from a borehole.
b. In rock drilling, the sludge from a borehole. Pryor, 3
A tool such as a drill used for boring.
Term used primarily by soil and foundation testing engineers for the
equipment customarily called a drill rod by drillers and miners.
Long
A group of special ceramic materials. Typical properties are great
hardness and mechanical strength, high melting point, low electrical
resistivity, and high thermal conductivity; impact resistance is low, but
thermal-shock resistance is generally good. Dodd
a. The cutting or drilling of a hole for blasting, water infusion,
exploration, or water or combustible gases drainage.
See also:percussive boring; rotary boring.
b. The drilling of deep holes for the exploitation or exploration of
oilfields. The term "drilling" is used similarly in connection with
metalliferous deposits. CTD
a. A rod, made in various lengths, usually with a single chisel cutting
edge, for hand drilling in rock. The blows are given by a sledge hammer.
Nelson
b. A revolving or stationary bar carrying one or more cutters or drills
for boring. Fay
See:drill log
Used by the soil and foundation testing profession as a syn. for boreholes
and/or the materials removed from a borehole. CF:cuttings; sample.
Long
An isometric mineral, 1[Cu5 FeS4 ] ; metallic; brownish
bronze tarnishing to iridescent blue and purple; brittle; massive; in
hypogene and contact metamorphic deposits and mafic rocks; a valuable
source of copper. Syn:erubescite; variegated copper ore; peacock ore;
horseflesh ore; poikilit; purple copper ore; variegated ore.
The element is not found free in nature, but occurs as orthoboric acid in
volcanic spring waters and as borates in borax and colemanite. The most
important source of boron is the mineral rasorite, also known as kernite.
Symbol, B. Amorphous boron is used in pyrotechnic flares and in rockets as
an igniter; the most important compound, boric acid or boracic acid, is
used as an antiseptic; borax is used as a cleansing flux in welding and as
a water softener. The isotope boron-10 is used in nuclear reactors; the
nitride has lubricating properties similar to those of graphite; and the
hydrides have been studied for use as rocket fuels.
Handbook of Chemistry and Physics, 3
See:ulexite
Probably not a true compound, but instead a solution of varying amounts of
carbon in a slightly distorted boron lattice; symbol, BC; black; hexagonal
rhombohedral crystals; ranking next to diamond in hardness, 9.3 on the
Mohs scale; and melting point, 2,350 degrees C. Used in powder form as an
abrasive and in molded form as an abrasion resister.
Syn:tetraboron carbide
A former name for ulexite.
White; symbol, BN; hexagonal rhombohedral, crystals or powder; the powder
has a Mohs hardness of 2; sublimes at about 3,000 degrees C; anisotropic;
some properties vary according to the method of preparation and the
crystal form. Used as a refractory; a high-temperature lubricant, as in
glass molds; in furnace insulation; and in molten-metal pump parts.
CCD, 2; Handbook of Chemistry and Physics, 2
Symbol, BPO; sp gr, 2.81; vaporizes at 1,400 degrees C; related
structurally to high cristobalite. It has been used as a constituent of a
ceramic body that fires to a translucent porcelain at 1,000 degrees C.
Dodd
Symbol, BP; melting point, greater than 2,000 degrees C, but readily
oxidizes, which limits its potential use. Dodd