A montmorillonite-type clay formed by the alteration of volcanic ash. It
varies in composition and is usually highly colloidal and plastic.
Swelling bentonite is so named because of its capacity to absorb large
amounts of water accompanied by an enormous increase in volume. Occurs in
thin deposits in the Cretaceous and Tertiary rocks of the Western United
States. It is used for making refractory linings, water softening,
decolorizing oils, thickening drilling muds, and preparing fine grouting
fluids. As a mud flush, bentonite is used at a concentration of about 3
lb/ft3 (48.1 kg/m3 ) of water. Syn:Denver mud;
volcanic clay. See also:clay
Bentonite.
A stationary screen constructed in the form of an arc of a circle and
arranged as a chute over which the clean coal from a cyclone washer passes
to the orthodox rinsing screen. In the United States, the bent screen is
used in magnetite recovery from cyclone washers. Nelson
See:phenol
A portable instrument designed specif. for measuring low concentrations of
benzol, which are potentially dangerous to the health of personnel.
Best, 1
A monoclinic mineral, Fe2+ Fe3+5 (PO4 )
4 (OH)5 .4H2 O ; a secondary mineral in iron deposits;
an alteration product of primary phosphates in pegmatites.
A circular, revolving, inclined iron pan in which concentrates are ground
with mercury and water by an iron ball. Gordon
In polarized-light microscopy, an optical device of variable compensation
for analysis of birefringence. CF:accessory plate
A pitchy black dike rock containing small phenocrysts of haueyne, apatite,
perovskite, melilite, and magnetite in a groundmass of the same minerals
with nepheline, biotite, and brown interstitial glass; from Kaiserstuhl,
Oberbergen, Baden, Germany. Syn:bergalith
See:bergalite
Various salts, commonly halotrichite. Hey, 1
Occurs naturally at Bergen an der Trieb, Saxony, with other uranium
minerals; named from locality, the older name being rejected as implying a
barian phosphuranylite rather than the barium analogue. Syn. for
barium-phosphuranylite. Hey, 2
A method of direct reduction of iron ore. The reduction of the ore was
carried out in interchangeable containers. The ore was heated to the
reduction temperature in one container, and then this container was moved
into the reducing zone. Osborne
See:lazulite
The element having the atomic number 97, the discovery of which was
announced by Thompson, Ghiorso, and Seaborg in 1950. They produced an
isotope of 4.5 h half-life, berkelium 243, by helium ion bombardment of
americium 241. Symbol, Bk; valences, 3 and 4; and the mass number of the
most stable isotope, 249. Handbook of Chemistry and Physics, 2
In optical mineralogy, an anomalous interference color of the first order;
e.g., some epidotes.
A soft iron containing phosphorus, which makes very fine smooth castings
and is used for ornaments and jewelry. Standard, 2
a. A horizontal shelf or ledge built into the embankment or sloping wall
of an open pit or quarry to break the continuity of an otherwise long
slope and to strengthen its stability or to catch and arrest slide
material. A berm may be used as a haulage road or serve as a bench above
which material is excavated from a bank or bench face. CF:bench
b. The space left between the upper edge of a cut and the toe of an
embankment. Seelye, 1
c. An artificial ridge of earth. Nichols, 2
d. Terraces that originate from the interruption of an erosion cycle with
rejuvenation of a stream in the mature stage of its development and
renewed dissection, leaving remnants of the earlier valley floor above
flood level. AGI
e. A nearly horizontal portion of the beach or backshore formed by the
deposit of material by wave action. Some beaches have no berms; others
have one or several. See also:bank height
A monoclinic mineral, Mn2+ Mn3+2 (PO4 )
2 (OH)2 .4H2 O ; in pegmatites.
Vertical distance from crest of berm to its underlying toe, as in a bank
or bench.
Originally described by Stillman as fossil resin, but later shown by
Stanley-Brown to be a fungus impregnated by resinous material.
Tomkeieff