a. First developed as a fixed-blade device for continuous longwall mining
of narrow seams of friable coal, this machine is pulled along the coal
face, planing a narrow cut. Vibrating-blade planers were designed later in
an attempt to apply the technique to harder coal; they have also been
experimented with in the phosphate mines in western Montana and northern
Idaho.
b. A machine provided with a cutting tool having lateral and vertical
adjustment that is widely used in stone trimming. Both sides and tops of
blocks may be planed to desired dimensions. Some planers may be adjusted
to cut curved forms.
A triclinic mineral, Al6 (PO4 )2 (PO3 OH) (sub
2) (OH)8 .4H2 O ; turquoise group.
A type of schistosity characterized by the arrangement of tabular and
prismatic grains in parallel planes.
One of four types of slope failure. Plane shear failure results when a
natural plane of weakness, such as a fault, a shear zone, or bedding plane
exists within a slope and has a direction such as to provide a
preferential path for failure. Large intact portions of the slope rock may
slide along this plane surface. Woodruff
A state of strain in which all displacements that arise from deformation
are parallel to one plane, and the longitudinal strain is zero in one
principal direction. AGI
A state of stress in which one of the principal stresses is zero.
Ordinary field and topographic surveying in which Earth curvature is
disregarded and all measurements are made or reduced parallel to a plane
representing the surface of the Earth. The accuracy and precision of
results obtained by plane surveying may decrease as the area surveyed
increases in size. CF:geodetic surveying
a. An instrument for plotting the lines of a survey directly from the
observations; consisting essentially of a drawing board mounted on a
tripod and fitted with a ruler that is pointed at the object observed,
usually with the aid of a sighting device, such as a telescope.
Webster 3rd
b. An inclined ore-dressing table. Standard, 2
A drum containing planetary gearing that is used to control the motion of
the rope drums on certain types of mining machines. In planetary gearing,
which is used when a large ratio of speed reduction with only a few
operating gears is required, some or all of the gear wheels in the train
of mechanism have a motion about an axis and a revolution about the same
axis. Jones, 1
A type of machine lap employing a number of geared workholders that rotate
with an epicyclic motion between two stationary lapping plates. The
crystals being lapped, when contained in pentagonal holes in the
workholder, have an imposed rotatory motion. Also known as the
Hunt-Hoffman lap or Bendix lap. Am. Mineral., 2
Mill used for making very large reductions on slabs by one pass through
the mill. The mill consists of two large plain rolls, each surrounded by
many small work rolls. Osborne
A gearset consisting of an inner (sun) gear, an outer ring with internal
teeth, and two or more small (planet) gears meshed with both the sun and
the ring. Nichols, 1
See:slope engineer
Gearing in which one gear wheel revolves around another. Mason
An instrument for measuring the area of any plane figure by passing a
tracer around its boundary line. Webster 3rd
Analysis of patterns in a fabric diagram based on distribution of points
and areal comparisons. AGI
A map that presents only the relative horizontal positions of natural or
cultural features, by lines and symbols. It is distinguished from a
topographic map by the omission of relief in measurable form.
Syn:line map
a. The measurement of plane surfaces; e.g., the determination of
horizontal distances, angles, and areas on a map. AGI
b. The plan details of a map; the natural and cultural features of a
region (excluding relief) as shown on a map. AGI
A device for flattening thin sections cut for microscopic examination.
Standard, 2
The lining of a shaft with rectangular plank frames.
See also:box timbering
The whole community of rifting small plants and animals in layers of the
water. This term is frequently used to describe all life forms, regardless
of size, which have no means of significant self-locomotion. This
community can be divided into the phytoplankton (plants) and the
zooplankton (animals). Hy