An elongate, relatively depressed crustal unit or block that is bounded by
faults on its long sides. It is a structural form that may or may not be
geomorphologically expressed as a rift valley. Etymol: Ger., ditch.
CF:horst
A clamshell bucket fitted with teeth to assist digging. Nelson
Hooks used in lifting blocks of stone. They are used in pairs connected
with a chain, and are so constructed that the tension of the chain causes
them to adhere firmly to the rock.
A short railing or handle on heavy equipment used to assist operators and
other personnel in climbing up or down.
An ocean-bottom sampler that commonly operates by enclosing material from
the seafloor between two jaws upon contact with the bottom.
See also:Petersen grab
Collection of specimens of ore more or less at random from a heap, scatter
pile, or passing load. Used in connection with examination of the
characteristic minerals in the deposit rather than for valuation.
Pryor, 3
Essentially a hydraulic backhoe equipped with an extensible boom that
performs the three separate functions of excavation, backfill, and
grading. Carson, 1
a. The leveling of the land, or the bringing of a land surface or area to
a uniform or nearly uniform grade or slope through erosion,
transportation, and deposition; specif. the bringing of a streambed to a
slope at which the water is just able to transport the material delivered
to it. See also:degradation; aggradation. AGI
b. The proportion of material of each particle size, or the frequency
distribution of various sizes, constituting a particulate material such as
a soil, sediment, or sedimentary rock. The limits of each size are chosen
arbitrarily. AGI
a. A coal classification based on degree of purity, i.e., quantity of
inorganic material or ash left after burning. CF:type; rank.
AGI
b. The relative quantity or the percentage of ore-mineral or metal content
in an orebody. Syn:tenor
c. A degree of inclination, or a rate of ascent or descent, with respect
to the horizontal, of a road, railroad, embankment, conduit, or other
engineering structure; it is expressed as a ratio (vertical to
horizontal), a fraction (such as m/km or ft/mi), or a percentage (of
horizontal distance). CF:gradient
d. Height above sea level; actual elevation. Also, the elevation of the
finished surface of an engineering project (such as of a canal bed,
embankment top, or excavation bottom). AGI
e. A particular size (diameter), size range, or size class of particles of
a soil, sediment, or rock; a unit of a grade scale, such as clay grade,
silt grade, sand grade, or pebble grade. AGI
f. See:metamorphic grade
g. The classification of an ore according to the desired or worthless
material in it or according to value. Nelson
h. The degree of strength of a high explosive. Those above 40%
nitroglycerin are arbitrarily designated as high-grade dynamites, and
those below 40% nitroglycerin as low-grade dynamites.
i. In assaying, the percentage of the sought value or of each valuable
species in the ore. Pryor, 3
j. A term used to designate the extent to which metamorphism has advanced.
Found in such combinations as high- or low-grade metamorphism. CF:rank
Leet, 1
k. A particular occupational classification of employee in a mine.
Nelson
l. To sort and classify diamonds, such as drill diamonds, into quality
groupings, each group containing diamonds having somewhat similar
characteristics deemed to affect their fitness for use in a specific
manner; the least fit are considered as constituting the lowest quality of
grade. Long
m. See:rank
a. Said of a surface or feature when neither degradation nor aggradation
is occurring, or when both erosion and deposition are so well balanced
that the general slope of equilibrium is maintained. Syn:at grade
AGI
b. A geologic term pertaining to an unconsolidated sediment or to a
cemented detrital rock consisting of particles of essentially uniform size
or of particles lying within the limits of a single grade. Syn:sorted
AGI
c. An engineering term pertaining to a soil or an unconsolidated sediment
consisting of particles of several or many sizes or having a uniform or
equable distribution of particles from coarse to fine; e.g., a graded sand
containing coarse, medium, and fine particle sizes. The term is rarely
used in geology to refer to the sorting of the sediment, although this is
common among engineers. Ant: nongraded. AGI
A type of bedding in which each layer displays a gradual and progressive
change in particle size, usually from coarse at the base of the bed to
fine at the top. It may form under conditions in which the velocity of the
prevailing current declined in a gradual manner, as by deposition from a
single short-lived turbidity current. CF:grading
One of the three main size groups by which coal is sold by the National
Coal Board in Great Britain. It consists of coal screened between two
screens--with an upper and lower limit ranging from a top size of 1-1/2 to
2 in (38 to 51 mm) to a bottom size of 1/8 to 3/4 in (3.2 to 19 mm).
See also:large coal; smalls. Nelson
A sand containing some coarse, fine, and medium particle sizes. It is not
a uniform sand. Hammond
A stream in equilibrium, showing a balance between its transporting
capacity and the amount of material supplied to it, and thus between
degradation and aggradation in the stream channel. AGI
a. The baseline from which elevations are measured.
b. A line defining the intended grade of a roadway that is being driven.
Such a line is used to control the gradient of a roadway. BS, 7
a. A self-propelled or towed machine provided with a row of removing or
digging teeth and (behind) a blade to spread and level the material.
Syn:towed grader
b. A trommel-type airswept circular screen used in asbestos milling where
the fine rock and fiber dust are eliminated through medium-size perforated
plates. Arbiter
c. A machine with a centrally located blade that can be angled to cast to
either side, with independent hoist control on each side.
Nichols, 1
The force, due to gravity, that resists the movement of a vehicle up a
slope. Carson, 1
A systematic, arbitrary division of an essentially continuous range of
particle sizes (of a soil, sediment, or rock) into a series of classes or
scale units (or grades) for the purposes of standardization of terms and
of statistical analysis; it is usually logarithmic. Examples include Udden
scale and Tyler Standard scale. See also:Udden grade scale;
Wentworth scale. AGI
A stake indicating the amount of cut or fill required to bring the ground
to a specified level. Nichols, 1
The inclination of profile gradeline from the horizontal, expressed as a
percentage. Syn:rate of grade