Chapter XXV: Phosphate Rock

BY R. W. STONE

USES OF PHOSPHATE ROCK

Phosphate rock is chiefly used, after treatment with sulphuric acid, as an ingredient of artificial fertilizers. A small quantity is finely ground and used directly as fertilizer. Lesser quantities are used for making phosphoric acid and phosphorus. Phosphorus plays an important part in military operations, being used for incendiary bullets and smoke screens. Phosphorus also is a common ingredient of matches and the striking surface on boxes of safety matches, and it enters in small proportion into phosphor-bronze, phosphor-copper and phosphor-tin.

=Substitutes.=--Substitutes for phosphate rock may be classed as natural and artificial. Natural substitutes are phosphatic limestone; other phosphate-bearing minerals, such as apatite, nelsonite, and wavellite; guano; marl; animal excrement and bones. Artificial substitutes include basic slag and manufactured compounds, like ammonium phosphate.

GEOLOGICAL OCCURRENCE

Phosphate rock is a sedimentary deposit containing phosphate of lime. It occurs as a hard rock interstratified with beds of sandstone, shale, or other sediments; as amorphous nodular concretions or pebbles in stream deposits; and as a residuum from the decomposition of phosphatic dolomite or limestone, or other rocks containing phosphate of lime. Another type of deposit commonly classed as phosphate rock is the porous coralline or other limestone of tropical islands which has been permeated with phosphate leached from guano.

Phosphate deposits of the western United States, Algeria, Tunis, and Egypt are hard rock beds of the first type. Amorphous nodular deposits occur in South Carolina, part of Florida, Wales, England, Belgium, north-central and eastern France, and Russia. The deposits in Tennessee, Kentucky, and some of those in Florida are residual. Leached guano deposits are found on the islands of Aruba, Curacao, and Sombrero, in the West Indies, and on Christmas, Ocean, Makatea, Angaur and other islands in the Indian and South Pacific oceans.

The reserves in the United States are fairly well known and are estimated at 6,000,000,000 tons. Reserves of high-grade rock in Algeria and Tunis have been estimated at 300,000,000 tons. No information is at hand regarding the quantity of phosphate rock in Egypt or in Europe, except that Russia is believed to have 80,000,000 tons in one of its fields. The deposits in the South Pacific islands are estimated at 70,000,000 tons. Before the war the world’s output of phosphate rock was about 6,000,000 tons annually, of which about one-half was mined in the United States. The next largest production is made in northern Africa.

Phosphoric acid is derived also from apatite, a calcium phosphate that occurs in veins. Apatite has been mined in the Province of Quebec, Canada, and in Spain.

GEOGRAPHICAL DISTRIBUTION

In the Western Hemisphere phosphate rock is produced in the United States, in Canada, the Dutch West Indies, and French Guiana, and occurs in Peru and Chile.

=United States.=--The principal deposits of phosphate rock in the United States are in Florida, South Carolina, Tennessee, Kentucky, Arkansas, Montana, Idaho, Wyoming, and Utah. Although by far the largest deposits are in the western states, those deposits yield less than 1 per cent. of the whole because of the lack of a large near-by market and because of high freight rates on the crude rock. It is not a matter of common knowledge, but it is, nevertheless, a fact, that the western rock phosphate deposits are so extensive as to be practically inexhaustible, even if the entire world depended on them for its supply of phosphate.

The _Florida_ phosphate deposits, which are the most extensively developed in the United States, comprise three classes of phosphate--hard rock, land pebble, and river pebble. The first is highest grade, the second is produced in largest quantity, and the third is not mined at present. The hard-rock deposits lie in a narrow strip along the western part of the Florida peninsula from Suwanee County to Pasco County, a distance of approximately 100 miles. The land-pebble phosphate area, just east of Tampa, is about 30 miles long and 10 miles wide. Sales of Florida phosphate declined tremendously after 1913 through the restriction on exports by the war. In 1913 the sales were 2,500,000 tons, valued at $9,500,000, and in 1915 the production was 1,350,000 tons, valued at $3,700,000.

_South Carolina_ produces land rock phosphate in the vicinity of Charleston. River-pebble phosphate occurs in the same area but is not mined. Some of the South Carolina output has been exported annually. Sales decreased from 169,000 tons in 1911 to 83,000 in 1915, and the value in the same years from $673,000 to $311,000.

_Tennessee_ deposits of rock phosphate are in the west-central part and extreme northeast corner of the state; the latter have not been mined. Three types are recognized and known by their colors as brown, blue, and white rock; the last has not been mined recently. The brown rock is sold under guarantee of 70 to 80 per cent. tricalcium phosphate; the blue rock varies considerably in its phosphatic content. Sales of Tennessee phosphate in 1914 were 483,000 tons, valued at $1,823,000; by 1915 they had fallen to 390,000 tons, valued at $1,328,000.

_Kentucky_ has been an insignificant producer of phosphate rock in recent years. _Arkansas_ phosphate deposits are in the north-central part of the state. The output is small.

Four western states possess enormous deposits of high-grade rock phosphate, but their output is as yet insignificant, being only 3,000 to 5,000 tons a year. The producing states are Idaho, Utah, and Wyoming. Montana is not a producer, although it contains extensive deposits easy of access and close to rail transportation.

_Idaho_ has an unlimited supply of high-grade phosphate in the southeast part of the state. A small quantity is mined in Bear Lake County. The _Utah_ deposits are east of Great Salt Lake, in the Wasatch and Uintah ranges, and east of Bear Lake. These deposits are extensive, but the rock is leaner than the general run of the Idaho phosphate, averaging nearer 60 per cent. than 80 per cent. tricalcium phosphate. Western _Wyoming_ also is rich in rock phosphate, the deposits being mostly in the Owl Creek, Wind River, Gros Ventre, and Salt River ranges. Some of the beds are thick, carrying 80 per cent. tricalcium phosphate, and extend for many miles. They constitute a reserve supply that may be called inexhaustible. Small local demand for fertilizer and lack of cheap transportation may retard for some years the development of the great and rich western deposits.

An estimate of the quantity of rock phosphate available in the United States was made several years ago and need not be revised to account for that mined in the meantime. It is repeated here:

RESERVES OF PHOSPHATE ROCK IN THE UNITED STATES

Long tons
Florida 227,000,000
Tennessee 88,000,000
South Carolina 9,000,000
Kentucky 1,000,000
Arkansas 20,000,000
-----------
345,000,000
Western States: Montana, Idaho, Utah, and Wyoming 5,367,082,000
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Total 5,712,082,000

=Canada.=--The principal phosphatic rock in Canada is apatite, which occurs in workable quantity in two main districts--one in the Province of _Ontario_, the other in the Province of _Quebec_. These deposits, which were worked mainly by quarrying, are now practically abandoned. Rock phosphate occurs in a thin bed near Banff, _Alberta_, but is not used.

=South America.=--In Aruba and Curacao, islands of the _Dutch West Indies_, off the coast of Venezuela, are deposits of phosphate rock, from which a small quantity is mined and shipped to Europe. It is reported that the output in 1914 was about 100,000 tons, averaging 85 to 90 per cent. of calcium phosphate.

In _Peru_, in the Department of Ica, is a deposit of nodular lime phosphate, which is not used because of a local preference for guano.

A large, rich deposit of phosphate is reported in _Chile_, about 300 miles north of Valparaiso, but has not been developed as yet.

Phosphate deposits occur on the Island of Salut and on the Connetables, close to the coast of _French Guiana_. The rock is exported.

=Europe.=--The high-grade phosphate deposits of _Belgium_ are exhausted, only low-grade deposits remaining. The rock is found in layers and pockets, and carries between 25 and 65 per cent. of bone phosphate. The production from 1911 to 1913 averaged more than 200,000 tons annually.

The principal deposits in _France_ are in the Somme and Oise basins. The best French deposits are higher grade than the Belgian, as they carry 50 to 80 per cent. of bone phosphate, but they are nearly exhausted, only low-grade material remaining. The production from 1910 to 1914 was about 300,000 tons annually.

Important deposits of phosphate rock in _Russia_ can be divided into the northern, central, and southern groups. The deposits of the southern group were the only ones exploited before the war. Their output was about 25,000 tons a year--very small in comparison with the size of the deposits, which are estimated to contain more than 1,500,000,000 tons. Some of the rock is high grade, carrying as much as 75 per cent. tricalcium phosphate, but the normal grade is about 50 per cent.

The only deposits worked extensively in _Spain_ are apatite veins in the Province of Caceras. After lying idle many years these deposits were reopened and produced 28,000 tons in 1917.

Low-grade phosphate in the form of beds of nodules occurs in _England_, and in _Wales_. The production has been slight because the deposits are too small for commercial exploitation.

=Africa.=--The principal deposits of phosphate rock in _Tunis_ are the Gafsa fields, in the southern half of the country. There phosphate occurs in beds several feet thick, but only those carrying more than 58 per cent. phosphate of lime are exploited. The deposits can be traced for several hundred miles, and constitute a reserve of hundreds of millions of tons. Tunis now produces more phosphate than any other foreign country, its annual output being between 1,500,000 and 2,000,000 tons, most of which goes to southern Europe.

The deposits of phosphate rock in _Algeria_ are continuations of those in Tunis, the important mining districts being in eastern Algeria. The production is over 500,000 tons a year, and the exported rock carries 58 to 68 per cent. of lime phosphate.

Extensive deposits of phosphate occur in _Egypt_, near the Red Sea, in thin and irregular beds of the same geologic age (Eocene) as the deposits in Tunis and Algeria. The best deposits average 70 per cent. lime phosphate and the output in 1916 was 125,000 tons. There are mines 20 miles from Port Safalga, and concessions 12 miles inland from Kosseir and also at Sebaia, on the eastern bank of the Nile between Keneh and Assouan. Beds of phosphate are found in other districts on both sides of the Nile valley. Practically all the raw rock phosphate produced contains 65 per cent. or more of tricalcium phosphate and is exported mainly to Japan.

Deposits of phosphate occur 80 to 120 kilometers from the city of _Tripoli_ in beds more than 1 meter thick. These beds probably are a continuation of the phosphate deposits in southern Tunis.

Deposits of phosphate are reported in _Morocco_ 125 kilometers south-southwest of Casa Blanca on the west coast and 70 kilometers from the end of a railroad. These deposits are said to be comparable to the Gafsa field, in Tunis.

It is reported that at Dielor, in _Senegal_, about the latitude of Cape Verde, the westernmost point on the African coast, there is a phosphate bed which is 2 meters thick to a depth of 64 meters. The rock carries only 50 per cent. tricalcium phosphate, so it is not workable under present conditions, especially in view of the abundant high-grade rock in Algeria and Tunis.

Phosphates have been found in _Natal_, near Weenen, Ladysmith, and Byrnetown, in the form of phosphatic shales and of nodules. The percentage of tricalcium phosphate in the phosphatic shales is too low for use in making superphosphates; the phosphatic nodules are of higher grade but not abundant enough to be of value.

=Asia and Australasia.=--In the government of Uralsk, in southwestern _Siberia_, bordering on the north end of the Caspian Sea, there is reported to be 600,000,000 tons of phosphate rock. It is said that the greater part of this material carries 17 to 20 per cent. phosphoric acid, which is equivalent to 36 to 43 per cent. tricalcium phosphate. The government of Turgai, which borders Uralsk on the east, is reported to contain 67,000,000 tons of phosphate rock, most of which carries 18 to 19 per cent. phosphoric acid, or about 40 per cent. tricalcium phosphate. The highest-grade material reported is 24 per cent. phosphoric acid, equivalent to about 52 per cent. tricalcium phosphate. All the phosphate therefore is low grade. No production is reported from either of the localities.

Low-grade phosphate rock, in sedimentary beds of considerable extent, and high-grade vein deposits are reported in _Palestine_, on the east side of the Jordan. The sedimentary deposits occur also on the west side of the Jordan. The known reserves are about 3,500,000 tons. The sedimentary deposits average about 48 per cent. and the vein deposits 77 per cent. tricalcium phosphate. As the vein material is suitable for export, these deposits have been explored by a French company, but available information indicates there has been no output.

_Islands in the North Pacific Ocean._--After the discovery of phosphate rock on _Rasa Island_, 500 miles east of Formosa, a number of years ago, a Japanese company was formed to exploit the deposits. The rock is rich, carrying 75 per cent. phosphate of lime, and the reserves are estimated at 2,800,000 tons. In 1915 Rasa Island yielded 50,000 tons. A former German supply of phosphate is on _Angaur Island_, in the Pelew group, east of the southern end of the Philippines. Reserves on this island are estimated at 2,000,000 to 4,000,000 tons of phosphate rock, mostly of high grade. Germany increased the output from 45,000 tons in 1910 to 90,000 tons in 1913. Japan has held this island since October, 1914, and is mining 30,000 tons or more phosphate annually.

Deposits of phosphate, consisting of replacements of dolomitic coralline limestone, and phosphatic guano are reported on several other islands in Oceania, as Baker and Fanning Islands, in _Polynesia_, and Fais Island, in the _West Caroline Islands_. It is probable that on other islands there are commercial deposits as yet undiscovered.

_Islands in Indian and South Pacific Oceans._--North of Adelaide, in _Australia_, are pockety deposits of phosphate; they are without regular stratification and are of varying quality. The annual output has been 4,000 to 6,000 tons for several years. In the Otago district, near Clarendon, _New Zealand_, beds of phosphate 3 to 12 feet thick rest in pockets in limestone. There has been very little if any production.

On _Christmas Island_ (Straits Settlements), which lies in the Indian Ocean 190 miles south of Java, rock carrying 80 per cent. of bone phosphate is quarried and shipped to Australia and Japan. The deposits seem to be irregular, but are estimated to contain several million tons of rock of very high grade. The island belongs to the government of Singapore. Exploitation of the deposits by the British began in 1900. Exports in 1913 were 150,000 tons.

Phosphate rock of high grade is mined on _Ocean Island_, in the Gilbert Archipelago, between the Marshall and Solomon Islands, east of New Guinea and north of New Zealand. On this and other so-called coral islands in the equatorial belt which for ages have been sea-bird rookeries, leachings from the guano have impregnated the limestone, forming phosphate rock many feet deep. The deposits on this island are said to be many millions of tons and are among the richest in the world. They have been mined since 1901, and have produced as high as 300,000 tons a year. In 1916 the output was 70,000 tons of rock carrying about 85 per cent. tricalcium phosphate. The island is a British possession.

Another British possession in the Gilbert Archipelago containing phosphate rock is _Pleasant Island_, which is also known as Nauru, or Ngaru, Island. The deposits are similar to those on Ocean and Christmas Islands, being very high in calcium phosphate and low in iron and alumina. Germany formerly owned this island, but it was taken over by the British in 1917.

Makatea, near Tahiti, in the _Society Islands_, is estimated to contain 10,000,000 tons of very high-grade phosphate rock, irregularly distributed between reefs and pinnacles of dolomite. The deposits were developed as recently as 1910 and yielded more than 300,000 tons before 1917. Some of the rock carries 85 per cent. lime phosphate. The island is a French possession.

RECENT CHANGES AND DEVELOPMENTS

When the World War began, exports of phosphate rock from the United States, ordinarily about 1,000,000 tons a year, were cut off and the annual production of the United States fell from 3,000,000 tons to 1,800,000 tons. There has been a strong recovery in the domestic industry and if labor and transportation conditions improve there should shortly be an annual production of nearly 3,000,000 tons for domestic consumption, or as much phosphate rock for our own use as formerly was produced for ourselves and a large export trade.

It is surmised that northern Africa will yield larger quantities in the future than during the pre-war period. Production in Algeria, Tunis, and Egypt was probably stimulated during the war on account of the large reduction in the quantity of American rock sent to Europe.

Japan doubtless will make a large output from the German deposits in Polynesia which came into her possession at the beginning of the war.

COMMERCIAL CONTROL

Ownership of the phosphate deposits in the United States is largely domestic; some of the Florida hard-rock deposits are owned by French and (before the war) German companies. The German-owned deposits were taken over by the Custodian of Alien-Enemy Property, and have doubtless passed into other hands. The phosphate deposits on Curacao, Dutch West Indies, are worked by the Curacao Phosphate Mining Co., which ships the output to England and Germany. Phosphate deposits in Algeria and Tunis are exploited by French companies. Some of the companies work under lease. La Compagnie des Phosphates de Paris and La Compagnie Algerienne des Phosphates have been mentioned as engaged in these fields. Deposits on the lower Nile and Red Sea are worked by the Egyptian Phosphate Co., a British concern, and by the Societa Egiziana per l’Estrazione de il Commercio dei Phosphati, a company managed by Italians. It is reported that much of the output goes to Japan. The Pacific Phosphate Co., Ltd., of London, operates under concession the phosphate deposits on Ocean and Pleasant islands. Japanese companies are mining phosphate on Rasa and Angaur islands.

POSITION OF LEADING NATIONS

The United States has the largest known deposits of phosphate rock in the world, and, as before the war, can supply the needs of other countries as well as her own. Since mining began about 55,000,000 tons have been mined, or less than 1 per cent. of reserves. Great Britain possesses phosphate in Egypt and on Christmas, Ocean and Pleasant islands, and has imported from the United States and probably from northern Africa. France and the other Mediterranean countries have an ample supply in Algeria and Tunis. Germany formerly possessed rich deposits of phosphate on Angaur Island, in the Pelew group, Polynesia, and on Pleasant and Ocean islands, but so far as known now lacks a source of supply. Japan has a large supply of high-grade phosphate at her disposal on Rasa and Angaur islands.

SUMMARY

The principal use of phosphate rock is as an ingredient of fertilizers. Lesser quantities are consumed in the manufacture of phosphoric acid, in phosphorus used in military operations, in the manufacture of matches, and in metallurgy. Both natural and artificial substitutes are available for many of the uses of phosphate rock.

Phosphate rock is a sedimentary deposit containing phosphate of lime. It occurs as a hard rock between beds of sandstone or shale, as amorphous nodular phosphates in stream deposits, and as a residuum from the decomposition of phosphatic dolomite, limestone, and other phosphate-bearing rocks. The porous limestone of tropical islands, where it is permeated with phosphate leached from guano, is commonly classed as phosphate rock.

The phosphate rock deposits of present commercial importance are situated in the United States, Algeria, Tunis, Egypt, and the islands of the Indian and South Pacific oceans, the United States possessing by far the largest reserves. Smaller deposits, either undeveloped or nearly exhausted, are in Canada, Venezuela, Chile, Belgium, France, Russia, England, Spain, South Australia, and New Zealand.

During the war the exports of phosphate rock from the United States decreased greatly. With the return to normal conditions, however, the United States should experience little difficulty in becoming once more the principal source of phosphate rock.

The principal phosphate-rock deposits are controlled politically by the United States, France (Algeria and Tunis), and Great Britain (Egypt). A number of phosphate-bearing islands in the Pacific Ocean were owned by Germany before the war, but have been seized by Great Britain and Japan.

The commercial control of the deposits of the United States is mainly in the hands of Americans, although German (before the war) and French interests own some of the Florida hard-rock deposits. The deposits of Algeria and Tunis are controlled by French companies. The Egyptian deposits are controlled by two companies, one British and the other Italian.

Germany will be without a source of supply under her own control now that she has lost her colonies.