A physiographic feature having a broad base and an apex pointing upward;
specif. the face on the end of a faceted spur, usually a remnant of a
fault plane at the base of a block mountain. A triangular facet may also
form by wave erosion of a mountain front or by glacial truncation of a
spur. Syn:spur-end facet
A method of ore reserve estimation based on the assumption that a linear
relationship exists between grade difference and the distance between all
drill holes. Krumlauf
In mineral deposits, texture produced when exsolved or replacement mineral
crystals are arranged in a triangular pattern, following the
crystallographic directions of the host mineral. AGI
To divide into triangles; esp. to use, survey, map, or determine by
triangulation. Etymol: back-formation from triangulation. AGI
a. A trigonometric operation for finding the directions and distances to
and the coordinates of a point by means of bearings from two fixed points
a known distance apart; specif. a method of surveying in which the
stations are points on the ground at the vertices of a chain or network of
triangles, whose angles are measured instrumentally, and whose sides are
derived by computation from selected sides or base lines, the lengths of
which are obtained by direct measurement on the ground or by computation
from other triangles. Triangulation is generally used where the area
surveyed is large and requires the use of geodetic methods.
CF:trilateration
b. The network or system of triangles into which any part of the Earth's
surface is divided in a trigonometric survey. AGI
A test in which a cylindrical specimen of rock encased in an impervious
membrane is subjected to a confining pressure and then loaded axially to
failure. See also:unconfined compression test
Syn:triaxial shear test
A subdivision of the rock association or kindred. A tribe is made up of
clans. See also:rock association
Two chemically dissimilar metals in mutual electrical contact. The
friction produced by the mechanical agitation of the two members of the
couple results in the flow of an electric current. The power of a
tribocouple is the magnitude of the current that it will generate under
specified conditions of friction. Osborne
Triboelectrostatic separation process
An electrostatic process under development, in which fine-size dry coal is
blown rapidly past a copper baffling device that imparts positive
triboelectric charges on the coal and negative charges on the associated
mineral matter. The material is introduced into an electrostatic
separator, where it is separated.
a. The property of some specimens of zinc sulfide of emitting sparks when
scratched. Fay
b. Luminescence in which electrons in a trapped state are released by
abrasion or crushing. CF:luminescence
a. Three leveling screws and footplate used to attach a theodolite or
surveyor's level to its tripod, level the instrument, and center it
precisely over its mark. Pryor, 3
b. The frame below a theodolite on which three foot screws are mounted.
See also:limb
See:bromoform
In mining, work on shares. Standard, 2
a. A system under which a syndicate of miners delivers coal at the pithead
at an agreed price. This system may be used where ore deposits are too
small and scattered to conduct normal mining activities. "Tributors" work
and deliver their ore to the owner and receive payment based on the ore's
ascertained value. Nelson
b. Working on a sharing basis. Pryor, 3
A compound, 3CaO.5Al2 O3 , formerly believed to be present
in high-alumina hydraulic cement. It is now known that a melt of this
composition consists of a mixture of CaO.2Al2 O3 and CaO.Al
2 O3 , the latter compound being responsible for the
hydraulic properties. Dodd
3CAO.SiO2 ; dissociates at approx. 1,900 degrees C to form CaO and
2CaO.SiO2 . This compound is the principal cementing constitutent
of Portland cement, small quantities of MgO and Al2 O3
usually being present in solid solution. Tricalcium silicate is also
present in stabilized dolomite refractories. Dodd
A former name for tyrolite. See also:tyrolite
A straight or curved hairlike crystallite, usually black. Trichites occur
singly or radially arranged in clusters and are found in glassy igneous
rocks. AGI
Colorless; stable; low-boiling; heavy; mobile; toxic; liquid; CHCl:CCl
2 . CCD, 2
Characteristic of a crystal showing three different colors in transmitted
light; limited to crystallization in the orthorhombic, monoclinic, and
triclinic systems. CF:pleochroism; dichroism.