Position of the vertical circle of a theodolite with respect to the
telescope, viewed from the eyepiece end. Pryor, 3
N. of Eng. The time during which a coal-getting machine is moving along
the face. Trist
The cutting of pieces of ore and rock from exposed faces of ore and waste.
The faces may be natural outcrops or faces exposed in surface trenches and
pits. Face samples may be taken by cutting grooves or channels of uniform
width and depth across the face or sections of the face or by picking off
small pieces all over the face, more or less at random.
An excavator base machine fitted with boom and bucket for excavating and
loading material from an exposed face above track level. Nelson
N. of Eng. A wire stretched along the face to control, directly or
indirectly, the running of the face conveyor. Trist
The system for transmitting signals from points on a conveyor face to the
operator at the control panel near the main gate.
See also:signaling system
a. The front slip of a coal seam. CF:back slip
b. An inclined joint in coal sloping away from the hewing face.
Arkell
A diamond inset in the face portion of a bit. CF:kerf stone
Long
a. One of the polished plane surfaces of a gemstone, cut so as to enhance
the stone's brilliance and beauty.
b. To cut facets.
c. A nearly planar surface produced on a rock fragment by abrasion, as by
wind sandblasting, by the grinding action of a glacier, or by a stream
that differentially removes material from the upstream side of a boulder,
cobble, or pebble inclined at 50 degrees or less to the direction of the
impinging current.
d. Asymmetrically scalloped rock surfaces. Syn:flute
e. Any plane surface produced by erosion or faulting and intersecting a
general slope of the land; e.g., a triangular facet.
f. Any part of a landscape defined as a unit for geographic study on the
basis of homogeneous topography.
A boulder that has been ground flat on one or more sides by the action of
natural agents, such as by glacier ice, streams, or wind.
CF:faceted pebble
A pebble on which facets have been developed by natural agents, such as by
wave erosion on a beach or by the grinding action of a glacier.
CF:faceted boulder
The end of a ridge that has been truncated or steeply beveled by stream
erosion, glaciation, or faulting. See also:truncated spur
The placing of safety posts at the working face to support the roof of the
mine. The safety post is the most important timber in a mine because
exposure is greater at this point than at any other since the newly
exposed top is always of unknown quality. See also:timbering
Kentucky
A mechanical device for holding stone during grinding and polishing facets
at the exact angles that theoretically produce the most brilliant stone.
Rarely used in fashioning diamonds or other valuable stone where
preservation of weight is more important than maximum brilliancy.
See:transfer point
A wall built to sustain a face cut into the earth, in distinction to a
retaining wall, which supports earth deposited behind it. Zern
A term of wide application, referring to such aspects of rock units as
rock type, mode of origin, composition, fossil content, or environment of
deposition. CF:lithofacies
A lateral or vertical variation in the lithologic or paleontologic
characteristics of contemporaneous sedimentary deposits. It is caused by,
or reflects, a change in the depositional environment. AGI
A line indicating equivalence in lithofacies development; e.g., a
particular value of the sand-to-shale ratio.
A group of animals characteristic of a given stratigraphic facies or
adapted to life in a restricted environment; e.g., the black-shale fauna
of the Middle and Upper Devonian of the Appalachian region of the United
States. AGI
A fossil, usually a single species or a genus, that is restricted to a
defined stratigraphic facies or is adapted to life in a restricted
environment. It prefers certain ecologic surroundings and may exist in
them from place to place with little change for long periods of time.
AGI