The summit line of elevated ground; the line of a watershed.
a. A subdued and commonly iridescent or metallic glitter that approaches
but is just short of optical reflection and that modifies the surface
luster of a mineral; e.g., the optical effect still visible in the body of
a gem (such as tiger's-eye) after its silky surface appearance has been
removed by polishing.
b. A luster that emanates from just beneath the surface of a mineral;
e.g., opalescence. CF:luster
A tamping roller with feet expanded at their outer tips.
Nichols, 1
A Scottish term for mica.
See:shear legs
a. A general term for a tabular igneous intrusion, e.g., dike and sill,
esp. if concordant or only slightly discordant. CF:intrusive vein
AGI
b. A term used in the Upper Mississippi lead-mining region of the United
States for galena occurring in thin, continuous masses. AGI
c. See:blanket
A mineral deposit that is generally stratiform, more or less horizontal,
and areally extensive relative to its thickness. AGI
A disk type of live roller conveyor equipped with air outlets from a
blower to remove dampness from processed sheet metal while being conveyed.
a. Several closely spaced parallel faults along which the wall rocks are
broken into thin sheets.
b. See:shear zone
A group of closely spaced, distinct parallel fractures filled with mineral
matter and separated by layers of barren rock.
See:shear zone
See:shear zone
Light steel poling boards driven down to protect trench sides from
collapse. Hammond
See:laminar flow
A term used in the Joplin district, Missouri, and applied to horizontal,
low-grade, disseminated zinc-lead deposits, covering an extensive area.
See also:sheet deposit
a. The development, in rock formations, of small, closely spaced, parallel
fractures.
b. In a restricted sense, the gently dipping joints that are essentially
parallel to the ground surface; they are more closely spaced near the
surface and become progressively farther apart with depth. Esp.
well-developed in granitic rocks. See also:bedding
AGI
A row of caps placed on blocks about 14 in (36 cm) high placed on top of
the drift sets when constructing the permanent floor in the stope. Round
poles are then laid lengthwise of the stope on the sheeting caps and are
covered with lagging. Lewis
An air hammer attachment that fits on plank ends so that they can be
driven without splintering. Nichols, 1
Push-type turnbuckles, used to set ditch bracing. Nichols, 1
See:sheet pile
See:sheet