A metric unit of land area equal to 10,000 m2 , 100 ares, or
2.471 acres. Abbrev. ha. AGI
A monoclinic mineral, Na0.3 (Mg,Li)3 Si4 O10
(F,OH)2 ; smectite group. CF:montmorillonite
A monoclinic mineral, 4[CaFeSi2 O6 ] ; pyroxene group; forms
series with diopside and johannsenite; a common rock-forming mineral in
iron-rich metamorphic rocks, limestone skarns, and fayalite-bearing
plutonic rocks.
Quartz crystals containing needles of goethite or some other iron oxide.
CF:hairstone
The establishment of an opposite position on a futures market from that
held and priced in the physical commodity. Without hedging, the physical
position would be at risk to price fluctuations. Wolff
A hexagonal mineral, Pb3 Ca2 (AsO4 )3 Cl ;
apatite group; yellowish-white; at Franklin, NJ, and various localities in
Sweden. CF:mimetite
a. A small body of coal left under a larger body as a support. Known also
as heel of coal. BCI
b. The mouth or collar of a borehole.
c. The fixed jaw on an adjustable-wrench safety clamp or on a rock
crusher. Long
d. A floor brace or socket for wall-bracing timbers. Nichols, 1
e. The trailing edge of an angled blade. Nichols, 1
f. Any material remaining in a vessel after removal of the main portion of
the contents.
Temporary planting of trees and shrubs. Nichols, 1
a. In blasting, the face of a shot farthest away from the charge.
Stauffer
b. The distance from the mouth of the drill hole to the corner of the
nearest free face; or that portion of the hole that is filled with the
tamping; or that portion of the coal to be broken that is entirely outside
the powder. Zern
The entire surface plant of the mine. Gordon
A surveying term used in spirit leveling for the height of the line of
sight of a leveling instrument above the adopted datum, in trigonometric
leveling for the height of the center of the theodolite above the ground
or station mark, in stadia surveying for the height of the center of the
telescope of the transit or telescopic alidade above the ground or station
mark, and in differential leveling for the height of the line of sight of
the telescope at the leveling instrument when the instrument is level.
Abbrev. HI. AGI
The arsenic analogue of uranocircite, Ba(UO2 )2 (PO4
)2 .12H2 O and its dehydration product with Ba(UO2 )
2 (AsO4 )2 .8H2 O (metaheinrichite); occur near
Lakeview, OR, and in the Black Forest, Germany.
See also:arsenuranocircite; metaheinrichite. Hey, 2
A hydrous borate of magnesium and potassium, colorless to white. Occurs in
small crystals sometimes aggregated. From Stassfurt, Germany.
Syn:hintzeite; kaliborite. Fay
A wax near ozocerite but elastic like caoutchouc; yellow; sp gr, 0.915. It
occurs at Ropa in Galicia. Syn:mineral caoutchouc
See:double helical bag conveyor
A conveyor for handling coal, grain, cement, or similar bulk materials. It
comprises a horizontal shaft, with helical paddles or ribbons, which turn
on its center line inside a stationary tube filled with the material.
See also:worm conveyor
A continuous screw-shaped steel joist lining for staple shafts. The lining
is fixed to the ground by strata bolts rigidly fixed every 120 degrees
without any yielding device. Developed in Germany and its use is claimed
to effect considerable overall savings. Nelson
Pertaining to a metamorphic-rock texture consisting of bands of inclusions
that indicate original bedding or schistosity of the parent rock and cut
through later-formed crystals of the metamorphic rock. The relict
inclusions commonly occur in porphyroblasts as curved and contorted
strings. The term was originally, but is no longer, confined to
microscopic texture. Also spelled: helizitic. CF:poikiloblastic
AGI
A distorted twiglike lateral projection of calcium carbonate, found in
caves, etc. CF:stalactite; stalagmite. See:anemolite
Standard, 2
A clear yellow variety of beryl found near Rossing, Namibia, and prized as
a gemstone. Also spelled helidor. CF:golden beryl
A whitish to reddish-gray aventurine oligoclase with internal yellowish or
reddish firelike reflections. Syn:sunstone