Mineral Facts and Problems: 1960 Edition Page: 97
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BERYLLIUM
implantations with some beryllium compounds.
Acute inflammatory conditions of skin and
mucous surfaces can be caused by contact with
dusts, fumes, or mists of certain compounds of
beryllium. The respiratory types, acute and
chronic, can be received from breathing certain
dusts, mists, or fumes containing the element.
Most of the victims of acute beryllium-induced
respiratory disease recover rapidly and without
permanent injury, but a few have been afflicted
by the chronic form for several years with
serious consequences. Modern control practices
have practically eliminated new cases of disease
from beryllium.
Little is known about berylliosis, but much
has been done by the beryllium industry to pre-
vent the disease. Working places are kept
clean; workers are required to wash their hands
frequently; clothing is laundered regularly;
dusts, fumes, and mists are caught at the source
and deposited in dust collectors; and numerous
other precautions including medical programs
have been adopted to make working conditions
safe.
TECHNOLOGY
GEOLOGY
The beryllium content of the earth's crust
has been estimated to be 6 parts per million,
compared with 16 parts per milllion for lead.
About 30 minerals contain beryllium, and in
50 other minerals the occurrence of the element
is sporadic (12). Beryl, bertrandite, chryso-
beryl, helvite, and phenacite are the most com-
mon beryllium minerals, and all of them may
be found in pegmatite and other deposits.
Excepting helvite, each of these minerals con-
tains 5 percent or more beryllium. Beryl has
been the only mineral found in sufficient quan-
tity and rich enough concentration to qualify
as an ore mineral of beryllium. Beryllium min-
erals are not readily recognized in the field and,
like many other metals that once were scarce,
may be found in unsuspected sources.
Beryllium occurs principally in granitic and
syenitic intrusive igneous rocks, chiefly pegma-
tites, granites, nepheline syenites, and in a few
sediments derived from these rocks. Some
quartz veins and pegmatites rich in quartz con-
tain the element. Beryllium also occurs in a
few replacement deposits, chiefly those classi-
fied as contact metamorphic (2).
The world's principal sources of beryl are
heterogeneous granite pegmatites, where the
mineral occurs in enriched zones, filled frac-
tures, and replacement bodies. Homogenous
pegmatites have yielded little beryl. The prin-
cipal beryl deposits are found in zones that usu-
ally contain only a few thousand tons of
pegmatite rock; however, some deposits contain97
a million tons or more of rock. Certain zones
in some pegmatites contain more beryl than
others. Sometimes beryl is found in shoots that
are parts of zones. When beryl occurs in zoned
pegmatites the larger crystals usually are found
near the core and the fine-grained crystals near
the outer zone.
Beryl has also been found in quartz veins
with cassiterite, wolframite, molybdenite, and
other minerals.
Replacement deposits that contain beryllium
ore principally tactites and emerald-bearing
schists. Helvite is usually the chief beryllium
mineral of tactites and related rocks.
Nepheline syenites and other nepheline rocks
have been reported to contain small quantities
of beryllium. The element probably occurs in
nepheline, sodalite, mica, tourmaline, feldspar,
amphibole, and pyroxene. No nepheline rocks
have been found in the United States that were
rich in beryllium.
Certain granites and sediments, such as clays
derived from granitic and syenitic rocks, some-
times contain beryllium minerals. A few al-
luvial deposits derived from pegmatites have
been mined for beryl in some parts of the world.
Beryllium has also been found in coal.
Quartz veins found in schist and granite in
Park County, Colo., are unusual sources of com-
mercial beryl.
MINING
Great care must be taken in pegmatite mining
not to damage the sheet mica or reduce the
beryl to sizes too small to be cobbed. Pegma-
tite deposits that can be mined for beryl alone
are rare, and only a few deposits have been
found that contain more than 100 tons of beryl;
however, some of these deposits contain several
thousand tons of beryl. Occasionally beryl is
mined alone; however, usually it is obtained as
a byproduct in mining for feldspar, mica, and
spodumene and sometimes as a coproduct in
mining for columbite and tantalite.
Some pegmatite deposits are mined on a small
scale, usually by crude opencut methods (11).
Mining is begun on an outcrop where the min-
erals of value can be readily seen, and cuts are
made or pits are sunk by drilling and blasting
the rock. Hand drilling methods are some-
times used in out-of-way places, but usually
air-driven drills are used. The blasted rock is
hand-cobbed to recover valuable minerals in-
cluding beryl, and the waste rock is discarded.
The cycle of drilling, blasting, cobbing for
valuable minerals, and hauling waste to dumps
is repeated until the operation cannot be worked
economically. Sometimes the blasted rock is
coarsely crushed and passed over belts so that
valuable minerals can be sorted from it. The
balance of the rock may be reduced further in
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United States. Bureau of Mines. Mineral Facts and Problems: 1960 Edition, report, 1960; Washington D.C.. (https://digital.library.unt.edu/ark:/67531/metadc38790/m1/105/: accessed May 6, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.