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in the order of yield. Furthermore, the foreign spar is of lower grade than the mechanically treated spar from Illinois and Kentucky,

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Fig. 11.--Production of fluorspar in the United States, 1883–1913, and imports,

1910-1913.

and as fluorspar is of value chiefly according to its purity, purchasers find that the purer American spar is more efficient, and consequently

cheaper in the end. Problems concerning the milling and separation of fluorspar from its gangue minerals might be undertaken by the Government with benefit to the industry.

PARYTES.

In 1880 the output of barytes in the United States was about 12,000 short tons, while in 1914 the United States produced approximately 51,500 short tons, valued at $154,000. During that year 4,300 tons of crude barytes, 24,400 tons of ground barytes, and $178,600 worth of barium chemicals were imported, mainly from Germany. So far as known no barytes is exported from the United States.

Barytes is found in many States, but its commercial production at present is largely from Missouri, Georgia, North Carolina, Tennessee, South Carolina, Virginia, and Kentucky. Workable deposits exist in California, Nevada, Idaho, and in about all of the Atlantic seaboard States. A large deposit of high-grade barytes was recently discovered by the United States Geological Survey on the coast of southeast Alaska. The United States, therefore, has an ample supply of the crude mineral.

The principal use of barytes is in the manufacture of lithopone, a white paint consisting essentially of barium sulphate and zinc sulphide. Considerable quantities of ground barytes are used in the manufacture of rubber, mixed paints, artificial ivory, as a filler for heavy glazed paper, and in the manufacture of fireworks and night signals. Heretofore only small quantities of barium chemicals have been manufactured in this country, but with the stoppage of foreign supplies during the last few months the barytes chemical industry has begun to awaken, and there are now several companies making barium salts, such as chloride, peroxide, nitrate, etc.

European ores have been particularly used on the Atlantic seaboard, where they could formerly be obtained cheaper than domestic barytes. Our independence of Europe is not a question of our supply of barytes, but rather of better recovery in mining and treatment so as to cut the cost of production. With proper crushing, washing, and concentrating the Georgia barytes, containing 90 per cent barium sulphate, could be made into a 96 per cent product, and at small cost. The methods of mining are wasteful, and in most mines pieces of barytes under an inch in diameter are not recovered, although with very little additional equipment all could be saved.

STRONTIUM.

No strontium-bearing minerals were produced in the United States in 1880 and none in 1914, though there has been a very small domestic output in various intervening years. The recorded imports of strontium salts in 1914 amounted to $1,000, but it is known that in the neighborhood of 2,000 tons of salts were manufactured in this country from foreign ores largely of English origin. Sicily, England, and Germany also produced strontium ores.

Relatively small, irregular deposits of celestite, an ore of strontium, are known in New York, Ohio, Texas, West Virginia, Michigan, Pennsylvania, Kansas, Colorado, Tennessee, and California. Some celestite has been and could still be produced from the first four States. What seems to be larger and more persistent strontiumbearing deposits have been recently discovered in southern California and central Arizona.

The principal use of strontium salts in the United States is in the manufacture of fireworks and railway night signals. A very small quantity is used in medicine and in chemical work. Probably the largest use of strontium in Europe is in the refining of beet sugar, but as yet the strontium hydroxide method has not been adopted by American manufacturers, who use calcium hydroxide, which is much cheaper.

BORAX.

Of borax and boric acid, the former a necessity to every blacksmith, and both a convenience to every housekeeper, the United States has enough in the colemanite deposits of California to supply the domestic needs for many years, and other large supplies in “marshes” and playas located in California, Nevada, and Oregon. Although boron salts and minerals are imported into the United States, the matter is one of convenience and not of necessity.

MISCELLANEOUS MINERALS.

FELDSPAR AND KAOLIN.

The feldspar industry in the United States is conducted by small operators, few of the mines being sufficiently large to warrant the employment of technical men to carry on operations. The extensive reduction of existing waste, the preparation of a standard product, and the marketing of guaranteed material become possible when the losses are understood and the just requirements of the purchaser are realized. Investigations have been conducted by the department to discover the wastes and the possible by-products incident to production and point out methods for their recovery, to encourage efficiency in mining and treatment with the hope of enlarging the output and of increasing the quality and utilization of the product, and to determine by actual tests the physical constants and the general classification of the material from the various workable deposits. Among

the conclusions reached from the above investigations it is found that the raw material from the Appalachian region has no superior for color, but that there is great need of some central agency or depot by which the output of many small mines may be mixed and graded under the supervision of a trained ceramic chemist. Such control would insure the manufacturer receiving a product of known physical constants and would also insure a constant and ready market for the product. There can be no doubt of the United States being fully able to supply practically all of the feldspar and kaolin required for domestic consumption, and that in quality the materials now available in the Appalachian region are excelled by none.

In 1914 the production of feldspar in the United States was 135,000 tons, valued at $630,000, as compared with a production of 14,000 tons in 1883. Only small quantities of high-grade feldspar are imported from Canada and with the prepared grade of the domestic product there is but small reason that any should be imported. The exports to date have been none.

The feldspar quarries of the United States are confined to the eastern seaboard States, along the Appalachian Mountain Range, with the exception of a few quarries that have been developed in California.

The most important use of feldspar is for glazing of various grades of pottery and vitrified sanitary and electrical wares. It is also a constituent of the glaze of enamel ware, enamel brick, and tile. Attempts are being made to extract the potash content from feldspar, and when a process of this character is completed on a commercial scale it will then add another source to the domestic supply of potash.

The kaolin industry goes hand in hand with that of the feldspar industry inasmuch as kaolin is a decomposition product of the natural feldspar, both occurring in the same localities.

MICA.

Mica is indispensable in the manufacture of electrical apparatus and machinery, is widely used in glazing articles exposed to heat, and is also used for decorative purposes, as in the manufacture of wall papers. Other uses are in the preparation of lubricants, fancy paints, rubber goods, tar roofing papers, and boiler and pipe coverings. The manufacturing industries of the United States use more mica than those of any other one country. The supply is obtained from domestic mines and from imports, chiefly from India and Canada.

The production of sheet mica in the United States in 1880 amounted to 81,700 pounds, valued at $128,000. In 1913 this had increased to 1,700,000 pounds, valued at $353,500, with a production of 5,300 short tons of scrap mica, valued at $82,500, or a total value of

$436,000. These increases are shown graphically in fig. 12. In 1913, 2,239,000 pounds of sheet mica, valued at $943,000, were imported into the United States; chiefly from India and Canada. In 1913, $62,000 worth of unmanufactured and manufactured mica products were exported from the United States, chiefly to Belgium, Germany, England, France, Canada, Mexico, and Japan.

The domestic supply of mica has been obtained from about a dozen States, the more important being North Carolina, New Hampshire, South Dakota, Idaho, New Mexico, Colorado, Virginia, South Carolina, Alabama, and Georgia. It is probable that some of the promising deposits found in Maine, Massachusetts, Connecticut, New York, New Jersey, Pennsylvania, Maryland, Wyoming, California, Nevada, Washington, Arizona, and Utah could be worked under present conditions, and many of them will undoubtedly prove of future value.

The two chief factors in the development of the industry to its present size since 1880 are the use of large quantities of mica in small

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Fig. 12.—Production of sheet mica in 1880 and 1913 compared.

sheets for the electrical industry and the continually increasing demand for ground mica obtained from the scrap or waste in preparing sheet mica. The demand for scrap mica has made profitable the working of many mica mines that could not be profitably worked for large-sheet mica alone. The returns from some mines have been increased by sales of feldspar or gem minerals associated with the mica and saved as by-products. At the larger mines costs have been reduced by the use of better equipment. There is now practically no waste in manufacturing mica, since all of the scraps from trimming sheet mica are saved and used to make the higher grades of ground mica.

The United States can hardly be said to be independent of the rest of the world with industrial conditions as they are at present, but unquestionably the United States could obtain from within its borders mica enough for its needs, though of course at higier prices. Also it is possible that substitutes would be employed for the large sizes of sheet mica, if the cost of producing these sizes became excessive.

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