MAGNESITE
BY R. W. STONE
USES OF MAGNESITE
Magnesite and its derived products are used in a variety of industries,
the most essential of which, beyond doubt, is metallurgy. Owing to the
high fusion point and chemical inertness of the oxide of magnesium,
magnesite is one of the principal minerals used in the metallurgical
and other industries where highly refractory material is required. For
this purpose dead-burned magnesite is used in the form of brick or of
grains. Brick and shapes are employed for lining open-hearth steel
furnaces, welding, heating, and melting furnaces, reverberatories,
settlers, and furnaces for refining lead, copper converters, and
electrical furnaces. Crushed or granular magnesite is used for lining
the bottoms of open-hearth steel furnaces, and in making crucibles and
cupels.
In the manufacture of the cement known as oxychloride or Sorel cement
the quantity of magnesite used is exceeded only by that used for
refractory purposes. This cement is employed largely for sanitary
flooring, and to a less extent for wall plaster, both interior and
exterior. It is used also instead of Portland cement for some forms
of exterior construction where quick and strong set is required.
Magnesite is used in the manufacture of wood-pulp paper on the Pacific
Coast, in fire-resisting paint, as a non-conductor of heat in pipe and
furnace coverings, and in the manufacture of magnesium chloride, light
carbonate, and other products, including metallic magnesium.
GEOLOGICAL OCCURRENCE
Deposits of magnesite are widely distributed throughout the world and
occur in two distinct forms, amorphous and crystalline. Amorphous
magnesite, the most common form, is fine-grained, and compact; it
is usually found in veins or masses in serpentine resulting from
the alteration of magnesia-rich rocks of the peridotite family. To
this group belong the Grecian deposits, nearly all the California
deposits, and those in Mexico, Venezuela, and other parts of the
world. Crystalline magnesite is medium to coarse grained, and occurs
as masses in limestone, dolomite or associated sediments which have
been metamorphosed. The principal deposits of this class are those in
Austria, Hungary, Quebec, and Washington.
Deposits of magnesite are regarded as having originated in three
ways. The massive non-crystalline variety, such as that in California
and Greece, is believed to have been formed by the decomposition of
serpentine. Magnesite deposits near Bissel, California, and on Muddy
River, near St. Thomas, Nevada, are said to be of sedimentary origin.
The Austro-Hungarian, Washington, and Quebec deposits are regarded
as resulting from the replacement of calcareous sedimentary rocks by
magnesian-bearing solutions.
Magnesite deposits that occur as veins in connection with serpentinized
magnesian rocks probably are formed both from the breaking down of the
serpentine-making minerals and from the serpentine itself. It seems
probable that usually both serpentine and magnesite are formed in the
process of decay of the original minerals in peridotite and the allied
basic rocks, and that during the decay of the serpentine the formation
of magnesite continues. In any case the magnesia or magnesian mineral
is changed to carbonate, dissolved by percolating water charged with
carbon dioxide, and precipitated in cracks and crevices as veins. When
formed in this way the magnesite occurs in large and small veins,
lenses, and stockwork, and its distribution and extent are erratic.
It seems fair to assume that these deposits may extend to the limit
of depth of easily circulating surface waters, which in favorable
conditions may be several hundred feet. Faulting, on the other hand, is
as likely to cut the veins off in depth as in length. Any estimate of
available tonnage of magnesite in deposits of this type therefore is
unwarranted in advance of development work.
Sedimentary deposits such as those of Bissel, California, and near St.
Thomas, Nevada, are by their nature more regular in occurrence, and
their tonnage can be estimated from the outcrop in natural exposures
and prospects.
Replacement deposits like those in Washington and Quebec are not so
regular as the sedimentary deposits, but are more regular than the
veins, and tonnage estimates may be based on the surface exposure and
an assumed depth of 50 to 100 feet.
GEOGRAPHICAL DISTRIBUTION
The known distribution of magnesite deposits is as follows:
_North America._
Canada: Quebec, British Columbia and elsewhere.
United States: California, Washington, Nevada.
Mexico: Lower California on Santa Margarita Island.
_South America._
Venezuela: Island of Margarita.
_Europe._
Austria, Hungary, Germany, Greece, Italy, Macedonia, Norway, Sweden,
Russia.
_Africa._
Transvaal, Rhodesia, Portuguese West Africa.
_Asia._
India, in Madras and Mysore.
_Australia._
Queensland, New South Wales, South Australia, Tasmania.
_Oceania._
New Caledonia.
The following description by countries is in the order given above:
=North America.=
_Canada._--The principal magnesite deposits in Canada are in the
Grenville district, Argenteuil County, _Quebec_, where the mineral is
associated with serpentine, dolomite, and other minerals. The magnesite
in the Grenville district is a glistening cream-white to milk-white
or gray material that occurs in extensive masses associated with
bands or lenses of dark green to light-yellow serpentine. Throughout
the great mass of the deposits the magnesite and dolomite are so
similar in appearance that the detecting of dolomite is difficult.
There is considerable positive evidence in support of the hypothesis
that the deposits have been formed by the solution and replacement
of crystalline limestone through the agency of magnesia-rich
solutions. Outcrops of the deposits are up to 1,000 feet long and 300
feet wide. It is estimated that there are in sight 686,900 tons of
magnesite containing less than 12 per cent. CaO and 483,700 tons of
magnesite-dolomite containing more than 12 per cent. CaO.
In the Atlin mining district, in _British Columbia_, both magnesite
and hydromagnesite have been noted, but the extensive masses of
hydromagnesite near the town of Atlin are the most important. These
deposits are superficial beds of fine powdery white hydromagnesite 6 to
8 feet thick, that cover areas up to 18 acres in extent. Two groups of
these deposits are estimated to contain 180,000 tons of hydromagnesite.
_United States._--Magnesite in commercial quantity occurs in
California, Nevada, and Washington. Reports of workable deposits in
other states have not been verified.
In _California_ there are magnesite deposits in many places throughout
the Coast Range and on the west slope of the Sierras, from Mendocino
and Placer counties on the north to Riverside County on the south.
Before the war, mining was limited to a few localities and the annual
output was about 10,000 tons, but the demand caused by large reduction
in imports started active prospecting and development, with the result
that in 1917 thirteen counties yielded a total of 211,663 tons, valued
at $2,116,630. In nine counties the deposits are large and in four
counties only small deposits have been found as yet. The most important
deposits are in Napa, Santa Clara, San Benito, and Tulare counties.
In 1917, 63 per cent. of the crude magnesite produced was mined in
Tulare County. Practically all of the California magnesite deposits
are irregular veins in serpentine, resulting from the alteration of
magnesian igneous rocks.
In the state of _Washington_ deposits of crystalline magnesite have
been found at several places. The Washington magnesite differs greatly
from the California deposits and occurs in larger masses. It is
coarsely crystalline, like marble or coarse textured dolomite, and is
red, pink, black, white, and gray. The Stevens County magnesite has
been formed by the replacement of lenses of dolomite in sedimentary
rocks. The recrystallization of the purer magnesian carbonate may have
been secondary and influenced by the intrusion of basic magnesian
rock which occurs above and below the magnesite in some places. The
larger deposits are 200 or more feet thick and 1,000 or more feet
long. Estimates of one million tons within 100 feet of the surface are
reasonable for at least three of the deposits. Mining in Washington
began in December, 1916, with a production of 715 tons. The output in
1917 was 105,175 tons, valued at $783,188.
The only known deposit of magnesite in _Nevada_ is an extensive
sedimentary bed in the valley of Muddy River, Clark County. The
magnesite carries more than 5 per cent. lime and more than 11 per cent.
silica. It has not been developed.
The total production of magnesite in the United States in 1915 was
30,499 short tons; in 1916, 154,974 short tons; in 1917, 316,838 short
tons; and in 1918, 231,605 short tons.
_Mexico._--On the Island of Santa Margarita, in Magdalena Bay, _Lower
California_, are extensive deposits of magnesite from which exports
have been made to the United States. Walls of canyons in the mountains
show masses of magnesite several feet thick, and magnesite boulders
strew the stream beds. Large quantities can be obtained without mining
and need only to be broken up for shipment. An analysis of calcined
magnesite from Santa Margarita Island shows practically no silica,
lime, or iron.
=South America.=--The deposits on Margarita Island, _Venezuela_, are
of the amorphous or California type and occur in veins and stockwork.
No information is available regarding their extent, but 500 tons were
exported to the United States in 1915.
=Europe.=--The magnesite deposits of _Austria_ and _Hungary_, which
until recently furnished much of the world’s supply, extend along a
northeast line for several hundred miles across the two countries.
The mineral occurs in lenses. A large deposit near Veitsch, Austria,
measures 700 to 800 feet from the top to the base. The ore is quarried
in a series of benches. Another very large deposit in Austria is at
Radenthein. The magnesite is quarried by great cuts, and lowered by
gravity to rotary kilns. Calcining is done near the mine and both grain
and magnesite bricks are shipped. The property was owned by Americans
before the war and much of the output went to American ports.
The magnesite in these deposits is crystalline and occurs in dolomite,
probably of Carboniferous age, from which it was derived by the
infiltration of magnesium carbonate solutions and the leaching out of
soluble calcium carbonate. It is finely to coarsely crystalline, yellow
or bluish-white, carries 3 to 4.5 per cent. iron oxide, less than 2 per
cent. silica, and less than 3 per cent. lime. It calcines readily to
the dead-burned state and makes satisfactory grain magnesite and brick
for refractory purposes.
Deposits of magnesite were worked for many years near Frankenstein,
Silesia, _Germany_.
In the Province of Santander, in northern _Spain_, coarse crystalline
magnesite lying in Lower Cretaceous limestone and dolomite has been
mined for a number of years. The production in 1915 was 1,400 tons.
In _Greece_, magnesite is of the non-crystalline type and occurs
associated with serpentine in veins and masses. The most important
deposits are on the Island of Euboea. The Euboean deposits are all
close to the seashore, and under normal conditions cheap water
transportation to the principal magnesite markets of the world is
available. The production of Greek magnesite in 1914 was mainly in the
hands of three companies: the Anglo-Greek Magnesite Co., 24 Finsbury
Sq., London; the Société Hellenique des Mines, Athens; and the Hellenic
Magnesite Co., Athens. The distribution of the magnesite is controlled
by the London company. The Anglo-Greek Magnesite Co. works mines at
Galataki and Afration, in Euboea. At the Galataki mines the vein of
ore exposed is known to be 1,300 feet long and 50 to 60 feet wide. The
Société Hellenique des Mines (now called The Financial Corporation of
Greece, Ltd.,) controls the production of several mines at Mantoudi,
Limni, Larimna, etc. The Hellenic Magnesite Co. obtains most of its
ore from surface excavations. In 1912 the production of magnesite by
several companies in Greece, (not including the Hellenic Magnesite Co.)
was as follows: Raw magnesite, 87,338 tons; calcined magnesite, 30,645
tons; dead-burned magnesite, 3,201 tons. This is equivalent to about
150,000 tons of crude ore, and does not include the product of one of
the three largest producers.
The magnesite from Greece and that from California are practically
identical in physical and chemical character, but prior to 1915 the
California material could not compete with the Grecian in the New York
market, because of the transcontinental freight rate being so high in
comparison with the ocean freight on material brought as ballast.
Magnesite is found in large quantities in _Macedonia_, occurring as
veins in serpentine.
Magnesite deposits, formerly worked, occur in _Italy_ in the Turin
district, and on the Island of Elba. None of the deposits seems to be
large. An analysis of magnesite from the Island of Elba shows over 8
per cent. silica, a trace of iron, and from 1 to 3.5 per cent. lime.
Magnesite occurs in _Norway_ as small veins in serpentine, but, unlike
other magnesite in serpentine, it is crystalline. It is remarkable in
that it shows no lime, but it carries over 4 per cent. iron and 9 per
cent. silica. It is calcined and made into brick.
Deposits similar to those in Norway are found in _Sweden_, but
on account of their situation, which entails heavy operating and
transportation expenses, it is doubtful if they will ever be able to
compete with cheaper European magnesite.
Magnesite has been mined in the Orenburg government, _Russia_. One mine
yielded 26,320 metric tons in 1906. Magnesite occurs also on the north
slope of the Caucasus Mountains.
=Africa.=--Extensive deposits of magnesite occur in the _Transvaal_,
as veins, that range up to 4 feet in thickness. The rock is used
for making carbon dioxide and oxychloride cement. Great deposits of
magnesite are reported in _Portuguese West Africa_. The deposits are
near, or associated with, boiling springs.
=Asia.=--The most important occurrence of magnesite in _India_ seems
to be in the Madras presidency, in the southern part of the peninsula
of Hindustan, where the mineral occurs in interlacing veins. The main
deposits have produced more than 2,000 tons in a single year.
Crystalline magnesite occurs in limestone in the _Manchuria_ mountains,
and is mined at Daisetsukyo for refractory purposes.
Magnesite is reported in _Asiatic Turkey_ about 75 kilometers from
Smyrna.
=Australia.=--The deposits of magnesite in _Queensland_ are so small
that they probably have no commercial value. Rounded blocks of pure
white magnesite outcrop in one locality in _New South Wales_, where
many thousands of tons are available at small cost. An analysis shows
99.01 per cent. magnesium carbonate and no lime. Large deposits of
magnesite are reported in _South Australia_. Extensive deposits also
occur on the north end of the west coast of _New Caledonia_. A small
quantity has been exported.
POLITICAL AND COMMERCIAL CONTROL
The magnesite deposits that play a notable part in the world’s economy
are situated in Canada, United States, Austria-Hungary, and Greece.
_United States._--The principal magnesite deposits in the State of
Washington are owned by the Northwest Magnesite Co., Spokane, Wash.;
Valley Magnesite Co., Spokane, Wash.; and American Mineral Production
Co., Chicago, Ill. The Northwest Magnesite Co. is the largest producer
in the Washington field and probably has made the largest investment.
The American Mineral Production Co. has a plant at Valley, Wash.; the
Valley Magnesite Co. has a deposit near Valley, but is not operating it.
The principal producers of magnesite in California in the summer
of 1918 were the Tulare Mining Co., with a mine near Porterville;
Porterville Magnesite Co. of California, with mine at Porterville;
Western Magnesite Development Co., with a mine at Red Mountain; and
Frank R. Sweasy, working the White Rock mine, Pope Valley, Napa County.
_Austria._--The Veitscher Magnesite Co., of Vienna, and the Magnesite
Co., Ltd., of Budapest, formed a combination or cartel, with the
understanding or agreement that all the sales of magnesite outside of
Austria and Hungary had to be made through Carl Spater & Co., a German
firm in Coblenz, Germany. The firm of Carl Spater & Co. formerly owned
the works of the Veitscher Magnesite Co., but sold out and obtained
the perpetual selling agency when the stock company was formed. The
Harbison-Walker Refractories Co., Pittsburgh, Penn., is said to have
been the American representative of Spater & Co.
The Austro-American Magnesite Co., whose deposit and works at
Radenthein, Austria, represent an investment of $1,800,000, is owned by
Americans. The entire stock is absolutely controlled by the principal
stockholders of the American Refractories Co., or was so controlled
before the war. The Austro-American Magnesite Co., it is claimed, was
doing virtually 95 per cent. of the magnesite business in England
before the war, and about 65 to 70 per cent. of the business in the
United States. This company has a capacity of 150,000 tons of calcined
magnesite a year.
When it was found that Carl Spater & Co., who handle both magnesite and
magnesite brick made by the Veitscher Magnesite Co. and the Magnesite
Co., Ltd., would not sell magnesite to the English refractory brick
makers, the Austro-American Magnesite Co. formed a selling company
in England, called the Anglo-Austrian Magnesite Co., of Sheffield,
England. The English company sold magnesite from the Austro-American
Magnesite Co. works at Radenthein, Austria, to all the refractory brick
manufacturers of England, and virtually took all the English trade from
the Germans.
The General Magnesite Co., of Budapest, has a magnesite deposit and
plant at Hizonvich (Hisnyoviz?), Hungary. The stock of this company
is believed to be owned principally by stockholders of the General
Refractories Co., 111 Broadway, New York. The balance of the stock,
believed to be about 40 per cent., is owned by some Hungarians of
Budapest, represented by Mr. Gunst, of Budapest, president of the
company.
According to the United States Department of Commerce,[154] there
are seven companies exploiting magnesite in Greece: The Anglo-Greek
Magnesite Co., Ltd., with head offices in London, England; the
Société Financière de Grèce, Solon and Lycabettus Streets, Athens;
The Internationale Magnesite Werken, with head offices in Rotterdam,
Netherlands; L. Carambelas, Limni, Euboea; N. Papantonatos, Limni,
Euboea; G. A. Georgidades, Athens, (exploiting a concession on behalf
of the General Magnesite & Magnesia Co., of Philadelphia); and Alexiou,
Daphnopotamos, Euboea. Most of the producers in 1917 had an abundance
of orders for magnesite to be used in the steel industry in France and
England.
[154] Commerce Reports, May 1, 1917.
SUMMARY
The principal and most essential use of magnesite is in metallurgy,
as a refractory material for lining furnaces. Magnesite is also used
in the manufacture of Sorel cement and of paper from wood-pulp, in
fire-resisting paints, as a non-conductor of heat in pipe and furnace
coverings, and in the manufacture of magnesium chloride, light
carbonate and other products, including metallic magnesium.
Magnesite occurs in two forms, amorphous and crystalline, and the
deposits originate in three ways: by the decomposition of serpentine,
as sedimentary deposits, and by the replacement of calcareous
sedimentary rocks by magnesium-bearing solutions. In advance of
development work it is impossible to make reliable estimates of
available tonnage of the first type, but fairly accurate estimates can
be made of deposits of the second and third types.
Developed magnesite deposits that have been productive at one time are
situated in California and Washington; in Quebec and British Columbia,
Canada; on Santa Margarita Island, Lower California; on the Island
of Margarita, Venezuela; in Austria-Hungary, Germany, Spain, Greece,
Macedonia, Russia, Norway, Transvaal, and India. Other deposits, some
of which have produced small amounts, are situated in Nevada, Ontario,
New Brunswick, on Cedros Island, Lower California; in Asia Minor,
Sweden, Rhodesia, Portuguese West Africa, Australia, Tasmania, and New
Caledonia. There is no reason to believe that there will be in the near
future any marked shift in the important sources of supply. In 1916
and 1917 the production from the deposits of the Pacific Coast of the
United States increased very rapidly, but since January, 1918, there
has been a severe slump in California production.
The magnesite deposits of California and Washington are owned by
a number of companies, all of them American. American refractory
manufacturers are believed to be interested in some of the Canadian
deposits. The deposits on Santa Margarita and Cedros islands, Lower
California, seem to be owned or operated for the most part by residents
of California. The deposits off the coast of Venezuela are held by
a Philadelphia company. Two of the large magnesite companies of
Austria-Hungary have agreed to make all of their sales outside of
Austria-Hungary through a German firm in Coblenz. Two other companies,
the Austro-American Magnesite Co. and the General Magnesite Co.,
are owned mainly by Americans. The magnesite deposits of Greece are
controlled by seven companies, one of them being English, one American,
one Dutch, and the remainder seemingly Greek. The other magnesite
deposits of the world are of little importance at present.