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fluoric acid. For ceramic products and glass manufacture a ground fluorspar analyzing 92 to 98 per cent of calcium fluoride and from 1 to 4 per cent of silica is demanded. For the manufacture of hydrofluoric acid the fluorspar is sold either in lump form or pulverized and is usually guaranteed to contain not less than 98 per cent of calcium fluoride and not over 1 per cent of silica. In the manufacture of hydrofluoric acid the fluorspar is treated with sulphuric acid, and in the process the presence of impurities in the fluorspar, such as calcium carbonate and silica, is very detrimental. The calcium carbonate neutralizes sulphuric acid, and its presence to the extent of 1 per cent or more causes considerable foaming upon mixing. Silica, if present, forms hydrofluosilicic acid in such proportion that for every part of silica nearly four parts of fluorspar and more than five parts of sulphuric acid of 66° B. are wasted, because for practically all applications of hydrofluoric acid the content of hydrofluosilicic acid is useless. Thus for 1.per cent of silica, 10 per cent should be deducted from the value of the fluorspar, and so on.

Fluorspar also finds use as a flux in some blast-furnace operations and in iron and brass furnaces; in the smelting of gold, silver, and copper ores; in the refining of copper, antimony, and lead; in the bond for the constituents of emery wheels; in carbon electrodes; in the manufacture of sodium fluoride used as a wood preservative; and in connection with the extraction of potash from feldspar and from flue dust of Portland cement works.

Data furnished by steel manufacturers who produced 32,234,761 long tons of basic open-hearth steel ingots in 1923, or 94.5 per cent of the total made by all steel manufacturers, show that they consumed 130,499 short tons of fluorspar during the year and had stocks on hand amounting to 47,219 short tons on January 1, 1924. If the few steel companies from which no reports were received consumed a like proportion of fluorspar, the figures given indicate a total consumption in all steel plants of about 138,000 tons and total stocks of about 49,900 tons. Similar information indicated a consumption of 104,000 tons for all plants in 1922 and stocks of about 65,000 tons on January 1, 1923. The reports show that the consumption of fluorspar per ton of steel produced in 1923 ranged from 4.5 to 24.2 pounds and averaged 8.1 pounds. In 1922 it ranged from 5.3 to 18.5 pounds and averaged 7.4 pounds.

The manufacturers of electric-furnace ferroalloys reported the consumption of 286 tons of fluorspar in 1923 and had stocks of 194 short tons on January 1, 1924.

The aggregate stocks of fluorspar at steel plants on January 1, 1924, were the lowest recorded for several years except 1921, so that if the prosperity generally forecast for the steel industry in 1924 arrives the fluorspar mines will be drawn upon to furnish a larger quantity of fluorspar than in 1923.

The shipments of domestic fluorspar plus the imports minus the exports give from year to year an index to the quantity made available for consumption and indicate its relative increase or decrease. The total quantity of all grades of fluorspar made available for consumption in 1923 was 161,928 short tons, a decrease of 6 per cent compared with 1922. The general relation between the total supply

Information according to J. E. Foster, General Chemical Co., published in Illinois Geol. Survey Bull. 41, 1920.

of fluorspar and the output of open-hearth steel may be noted by comparison of the following tables:

Fluorspar made available for consumption in the United States, 1919–1923, in short

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Reported by producers; none recorded by Bureau of Foreign and Domestic Commerce.

Open-hearth steel produced in the United States in 1919-1923, in long tons [From reports of the American Iron and Steel Institute]

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The large dependence of the fluorspar industry on the steel industry is clearly shown by the fact that by far the greater part of the fluorspar shipped is taken by steel manufacturers. There is considerable variation in the average value per ton of the fluorspar shipped to the several industries. The high value of fluorspar for hydrofluoric acid and glass and enameled ware is due to the high quality demanded.

Fluorspar shipped from mines in the United States in 1922 and 1923, by uses

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FLUORSPAR IN FOREIGN COUNTRIES

SOUTH AFRICA 5

The chief occurrences of fluorspar in South Africa are southeast of Ottoshoop, in the Zeerust district of the Transvaal, where a very large quantity appears to be available. The deposit has the form of a funnel-shaped pipe in disturbed dolomite and chert. The pipe measures 120 by 120 feet at the surface and 80 by 60 feet at a depth of 40 feet. In its peripheral portion the deposit consists of grayish and purple fluorspar, in places containing a little pyrite. The interior is very pure fluorspar, which in parts is good enough for optical work.

At present the fluorspar after being quarried is hauled by oxen up the incline, where the lump fluorspar is cut and loaded into wagons, the smaller material being run through 4-inch sieves to remove the dust.

The cost of production is about 12 shillings a ton f. o. b. railroad cars, made up of 5 shillings for production at the quarry and 7 shillings for sorting and wagon haul for 8 miles over bad roads. The cost of transportation to the Table Bay docks, Cape Town, is 20 shillings a ton. The cost of production will increase with the depth. The annual consumption of fluorspar in South Africa is about 250 to 350 tons. The principal consumers are the steel mills. During 1922 the owner of the deposit obtained an order for 2,000 tons for the United States and one for 200 tons for Australia, at a price of 55 shillings f. o. b. cars at Table Bay docks for material guaranteed to contain 98 per cent or more of calcium fluoride and less than 1 per cent of silica. The owner states that the price seems too low considering the cost of transportation from the quarry, the care that must be taken to insure the high purity required, and the loss due to sieving. These orders, it is stated, were taken to enable the operator to do some development work.

ITALY

The production of fluorspar in Italy showed rapid development in the years 1915 to 1918, when several thousand tons was produced by the military authorities from what is probably the largest deposit in Italy. The mine has been developed by five levels over a total length of 1,000 meters (3,281 feet) and a height of about 200 meters (656 feet). Along its surface exposure it shows an average width of 0.5 meter (1.6 feet); at the adit level this average increases to 1 meter (3.3 feet), and at the shaft level, 30 meters (98 feet) below, to 1.5 meters (4.9 feet). The highest-grade fluorspar is sorted from a picking belt in the mill, which should yield 20 to 30 tons a day of lump containing 95 per cent of calcium fluoride and less than 3 per cent of silica. A product containing 98 per cent of calcium fluoride is also obtained by hand sorting. To permit the transportation of 50 tons or more of fluorspar a day and to reduce the present cost a ropeway from the mine to Sarentino, a distance of 14 kilometers (8.7 miles), has been begun. The first section of 3 kilometers (2.2 miles) was about half completed in the autumn of 1923, and it is

* Donald, G, K., American consul, Johannesburg, South Africa, letter dated Jan. 31, 1923.

planned to finish the ropeway in 1924. From Sarentino the product is transported by autotrucks or teams to the railway station at Bolzano. The nearest port to Bolzano is Venice, and the cost of railroad transportation to Venice and loading charges at that port is said to be about $3.45 a ton. A flat rate, however, from Bolzano to New York and other Atlantic ports by way of Genoa has been obtained. 6 NORWAY

The production of fluorspar in Norway was small until 1915, when as a result of the war the country was obliged to utilize its own resources. The output from 1915 to 1919 amounted to 1,035 metric tons, but since 1919 there has been no organized effort at production, for the reason that mining is expensive and German fluorspar can be marketed in Norway at a price with which Norwegian operators can not profitably compete. The consumption of fluorspar in Norway is only about 500 tons annually.

The two chief deposits of fluorspar in Norway are near Kongsberg, Buskerud County, and near Dalen, Telemarken County. The deposits are some distance from the coast, making a railway haul necessary. At present freight rates are high. The fluorspar content of the Kongsberg deposit is stated to be 65 per cent. At Dalen the veins are from 3 to 3.5 meters (9.8 to 11.4 feet) wide, and the fluorspar content is from 75 to 80 per cent.

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No fluorspar has been mined in Switzerland during the last five years. In 1888-89 a group of German concerns exploited a fluorspar deposit at Oltschikopf, south of Brienzwyler, in the Canton of Berne. At this place a clear, colorless fluorspar was found that could be used in combination with borate and phosphate glass for making lenses for microscopes. The deposit was soon exhausted.

In June, 1922, the mineralogist of the University of Basel investigated a deposit of fluorspar discovered on the side of Mont Chemin between Martigny and Sembrancher, in the Canton of Valais, and found it of sufficient value to warrant exploitation. This discovery was due to the identification of fluorspar-previously believed to be quartz-in the gangue of a vein of galena that had been repeatedly exploited. There are two mines on this deposit.

The Des Trappistes mine is about 1 mile west of Sembrancher. It was reopened and operated for galena from 1918 to 1922 but is now closed. At present neither the depth nor the extent of the vein is known. No decrease in the thickness of the vein in depth has been found. The vein is approached on three different levels at a right angle and followed lengthwise for several hundred meters. It is on the average 1 meter (3.2 feet) thick, but in places it widens to 3 meters (9.8 feet). The length of the approaches is about 250 meters (820 feet), and that of the galleries about 300 meters (984 feet). The three levels are connected by pits and stairways. The deposit, as disclosed by the excavations, measures about 12,500

Carlson, H. E., American vice consul in charge, Christiania, Norway, letter dated Feb. 9, 1923. 'Holland, Philip, American consul, Basel, Switzerland, letter dated Jan. 29, 1923.

cubic meters (16,349 cubic yards), of which about 10,000 cubic meters (13,079 cubic yards) is exploitable. If the average content of fluorspar is 80 per cent, of galena 3 per cent, and of other minerals (quartz, calcite, zinc blende, copper pyrite) 17 per cent, the deposit would supply 8,000 cubic meters (10,664 cubic yards) or 12,500 metric tons of fluorspar and 300 cubic meters (392 cubic yards) or 2,250 metric tons of galena.

The Tête des Éconduits mine, about 1 miles northwest of the Des Trappistes mine, has been closed for many years. It was originally exploited for galena. Fluorspar appears in this mine in five strata of a combined thickness of 1.45 meters (4.8 feet); the intervening layers of sericite gneiss have a combined thickness of 1.8 meters (5.9 feet). The pit follows one of the veins, which consist of white fluorspar with traces of galena. No estimate has been made of the quantity of fluorspar it will yield.

The veins of both mines lie in conformity with the granite and porphyritic gneiss of the northeast end of the Mont Blanc group of mountains, trending N. 40° E. The veins are composed of galena, fluorspar, and a small quantity of silver. The white fluorspar is coarsely crystalline, granular, and brittle, crumbling easily into splintery fragments. In the earlier descriptions it was termed quartz, feldspar, and baryta. Quartz appears here and there in pockets and in strips. In some places fluorspar surrounds calcite crystals; in others small quantities of brown zinc blende and some iron pyrite are found; and a few show some copper pyrites.

An analysis of the fluorspar made at the mining office of the Mineralogical Petrographic Institute of the Technical University at Zurich gave 45.95 per cent of calcium, 43.65 per cent of fluorine, and 10.35 per cent of silica. The material consists therefore of 89.6 per cent of fluorspar and 10.35 per cent of quartz.

The facilities for transportation are excellent. Future exploitation is favored by the extensive and advantageously located galleries and by the uniformity of the vein. Galena and fluorspar can be easily separated by hand or by washing. The fluorspar is of greater economic value than the galena and can be used as an equivalent substitute for German and French fluorspar.

The consumption of fluorspar in Switzerland is small, there being no open-hearth steel manufacture in the country. The glass factories and iron foundries use minor quantities of fluorspar, which is obtained from France and Germany. This fluorspar is imported in lumps containing from 90 to 97 per cent of calcium fluoride, as the freight is much cheaper on these lumps than on the material in the state in which it comes out of the mine.

The present price of fluorspar loaded on railway cars at the mines in Germany is 29.60 francs a metric ton. This price includes a Swiss agent's commission of 10 per cent. The freight to the German railway station at Basel is about 7.40 francs a metric ton.

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