One that has crystallized in the tetragonal, trigonal, or hexagonal
crystal system and, therefore, has only one direction or axis of single
refraction. CF:biaxial stone
An obsolete syn. of monocline. CF:anticlinal bend
A test in which the volume change in a soil sample is observed when
subjected to increasing increments of load. A soil sample, which may be 3
in (7.6 cm) in diameter and 0.8 in (2 cm) thick, is compressed between two
porous stones, and the movement under load is noted. Hammond
a. A form of air travel; the air enters at one point, passes through the
workings, and goes out at a distant point. Recirculation is impossible
where unidirectional ventilation is used; thus the mine is safer than with
recirculated air. Lewis
b. Ventilation in which air in adjacent openings flows in the same
direction and is entirely fresh or exhaust air. Hartman, 2
The fundamental principle or doctrine that geologic processes and natural
laws now operating to modify the Earth's crust have acted in the same
regular manner and with essentially the same intensity throughout geologic
time, and that past geologic events can be explained by phenomena and
forces observable today; the classical concept that the present is the key
to the past. The doctrine does not imply that all change is at a uniform
rate and does not exclude minor local catastrophes.
Syn:principle of uniformity
An expression of variety in sizes of grains that constitute a granular
material. AGI
A low-density nitroglycerin powder type of equivalent sheathed explosive.
McAdam, 2
A transducer that cannot be actuated at its outputs by waves in such a
manner as to supply related waves at its inputs. Hy
a. State of a substance that has dissolved without dissociating into ions;
solute retaining its compounded state. Pryor, 3
b. State of a substance (in solid, gaseous, or liquid state) with atoms
that have neither an excess nor a deficiency of electrons, so that they
have no net charges.
A shop or mine run according to the requirements of a trade union.
CF:open shop
A direction in a crystal parallel to the highest symmetry axis; i.e., the
c axis in trigonal, tetragonal, and hexagonal systems; the three reference
axes in the orthorhombic system; and the b (or c in the first setting)
axis in the monoclinic system.
Smelter contracts make frequent use of the work unit. A unit means 1%.
Since a short ton contains 2,000 lb (907.2 kg), a unit is equivalent to 20
lb/t (10.0 kg/t) of ore. Lewis
A parallelepiped unit of atomic dimensions within a crystal structure,
containing all the atoms in the chemical unit in definite, fixed
positions; and all the symmetry elements of the space lattice from which
the whole crystal or crystal structure is built by regular repetitions of
this unit in three dimensions. CF:asymmetric unit
a. Applied to prepared coal as for analysis, and being the pure coal
substance considered altogether apart from extraneous or adventitious
material (moisture and mineral impurities), which may by accident or
through natural causes have become associated with the combustible organic
substance of the coal. AGI
b. The pure or actual coal substance as derived from taking into
consideration the corrected ash. The differentiation between the noncoal
substance of a sample being analyzed and the coal itself. It is expressed
by the formula: Unit coal = 1.00 - (W + 1.08 A + 0.55 S), where W = water,
A = ash, and S = sulfur. AGI
Where two or more veins unite, the oldest or prior location takes the vein
below the point of union, including all the space of intersection.
Ricketts
Recognition, study, application, and control of the principles and factors
utilized in a distinct and self-contained process (for example,
filtration). This avoids the duplication of effort that attends study of
filtration of oil, sugar, ore pulp, etc., as though each involved a unique
set of principles. Pryor, 3
The total pressure divided by the number of area units on which the load
is imposed, such as the diamonds in a diamond-bit crown, usually expressed
as pounds per square inch, tons per square foot, pounds per diamond, etc.
Long
Distinct and self-contained operations that can be studied individually.
In mineral processing, unit processes include crushing, grinding,
classification, gravity treatment, pulp conditioning, flotation,
thickening, leaching, and filtration. Pryor, 3
See:selenite plate
Unit tensile strain is the elongation per unit length; unit compressive
strain is the shortening per unit length; unit shear strain is the change
in angle (radians) between two lines originally at right angles to each
other. Roark
The stress or load per unit of area, usually taken per square inch of
section. For instance, if a bar is 1 in by 2 in (2.5 cm by 5.1 cm) in
section, the unit stress of the bar will be 1,000 divided by 2 (sectional
area) or 500 psi (3.4475 MPa). Zern