A monoclinic mineral, Na2 (Mg,Fe)3 (Al,Fe)2 Si (sub
8) O22 (OH)2 ; amphibole group with Fe3+ /(Fe
3+ +Al)=0.3-0.7 . CF:glaucophane
a. A joint in an igneous rock oriented more or less perpendicular to the
flow lines. Syn:tension joint
b. A joint in sedimentary rocks that crosses more prominent joints at
approximate right angles. AGI
In igneous rock, a fanlike pattern of cross joints that follow the arching
of the flow lineation. AGI
a. The structure commonly present in granular sedimentary rocks that
consists of tabular, irregularly lenticular, or wedge-shaped bodies lying
essentially parallel to the general stratification and which themselves
show a pronounced laminated structure in which the laminae are steeply
inclined to the general bedding. Syn:inclined bedding; crossbedding;
false bedding. AGI
b. An arrangement of laminations, transverse to the planes of
stratification of the strata concerned. They generally end abruptly at the
top, but in general tend to become more or less parallel to the bedding
planes below. AGI
c. Cross-stratification with foresets less than 1 cm thick.
Pettijohn, 1
The final ingredient added to a water gel or slurry, causing it to change
from a liquid to a gel. Dick, 2
A heading driven horizontally or nearly so, through or across inclined
strata.
A borehole drilled at an angle through the rock strata generally for the
purpose of combustible gases drainage. BS, 8
See:methane drainage
a. A development drift driven across the strata from the surface to
intersect and work coal seams. Nelson
b. A development heading driven from a level in one coal seam to intersect
and work upper or lower seams. Nelson
A roadway or airway driven across pitching measures on, or nearly on, a
level to reach a bed of coal or other objective, or to drain off water.
Zern
A track device that permits rail traffic to cross over another track which
heads in a different direction on the same level. Signal lights are
activated to avoid collision on the crossover.
Conveyor structure crossing the benches of open pit mines to reduce the
haul distance across the pit in terrace mining operations. SME, 1
Short poling boards placed horizontally to cover the gap between runners
in excavation trench timbering. See also:runner
a. A diagram or drawing that shows features transected by a given plane;
specif. a vertical section drawn at right angles to the longer axis of a
geologic feature, such as the trend of an orebody. AGI
b. An actual exposure or cut that shows transected geologic
features.--Adj: cross-sectional. Also spelled: cross-section. AGI
c. A profile portraying an interpretation of a vertical section of the
Earth explored by geophysical and/or geological methods.
d. A horizontal grid system laid out on the ground for determining
contours, quantities of earthwork, etc., by means of elevations of the
grid points. Seelye, 2
The area of a surface cut by a plane passing through the body and
perpendicular to the long axis of the body if one exists. If not, any such
area cut by a plane.
An ore reserve estimation method in which assay and other data are
projected to predetermined planes and the areas of influence of the assay
data are determined mainly by judgment. This method is helpful not only
for ore reserve computations, but also to mine planning. Krumlauf
a. A seismic spread that makes a large angle to the line of traverse; it
is used to determine the component of dip perpendicular to that line.
AGI
b. A seismic spread that is laid out in the pattern of a cross.
AGI
A vein of quartz that crosses a lode.
See:andalusite; staurolite; chiastolite; harmotome.
See:overhand stoping
a. The minor laminations are oblique to the plane of the main stratum that
they help to compose. See also:crossbedding
b. The arrangement of layers at one or more angles to the dip of the
formation. A cross-stratified unit is one with layers deposited at an
angle to the original dip of the formation. Many investigators have used
crossbedding and cross lamination as synonymous for cross-stratification,
but it is proposed to restrict the terms crossbedding and cross lamination
to a quantitative meaning depending on the thickness of the individual
layers or cross strata. Stokes