CHAPTER FIVE.

INDUSTRIAL MATERIALS.

The following mineral substances have been arbitrarily arranged under the general heading of "Industrial Materials," as distinguished from those which have a clearly defined classification, such as metals, salines, structural materials, etc.

These materials, many of which are mineral earths, are produced on a comparatively small scale at the present time. Almost without exception the possibilities of development along these lines are practically unlimited; and with increasing transportation, and other facilities, together with a steadily growing demand, the future for this branch of the mineral industry in California is indeed bright. There is scarcely a county in the State but might contribute to the output.

To date, production has been in the majority of instances dependent upon more or less of a strictly local market, and the following data will show the results of such a condition, not only in the widely varying amounts of a certain material produced from year to year, but in widely varying prices of the same material, often, in different sections of the State. Furthermore, the quality of this general class of material will be found to fluctuate, even in the same deposit, especially as regards price.

The following summary shows the value of the industrial materials produced in California during the years 1913-1914, with increase or decrease in each instance:

Asbestos.

Reference: State Mineralogist Reports XII, XIII. Bulletin 38. Though asbestos of various grades is known to exist widely distributed in California, the production for the year 1914 was but 51 tons, valued at $1,530, the combined result of several small shipments from a number of localities, including Shasta, Trinity, Placer, Calaveras, Alameda, and El Dorado counties. One firm has established a grinding and fiberizing plant in Oakland, and is now manufacturing a series of products in which both asbestos and magnesite play a part. These include steam pipe covering, composition flooring, and plaster for stucco work. The outlook is for a decided increase in the output of these materials during the coming year.

The real history of the development and use of asbestos dates back only about sixty years. Since that time the investigation as to its occurrence, uses, and methods of treatment has been continuous, and its application to everyday life has grown with wonderful rapidity. The first mill built to handle the crude ore and extract the fibre on a large scale by machinery was constructed in 1888.

The first production of asbestos in California was in 1887, when 30 tons were mined, having a crude value of $60 per ton, according to the State Mining Bureau reports.

The bulk of the world's supply of this mineral today comes from Canada; and Canadian asbestos, so far, leads in quality as well as in quantity.

The word "asbestos" (derived from the Greek meaning incombustible) as used here includes several minerals, from a strictly mineralogical standpoint. There are two main divisions, however: amphibole and chrysotile. The fibrous varieties of several of the amphiboles (silicates chiefly of lime, magnesia and iron), notably tremolite and actinolite, are called asbestos. Their fibres usually lie parallel to the fissures containing them. Amphibole asbestos possesses high refractory properties, but lacks strength of fibre, and is used principally for covering steam pipes and boilers. Chrysotile, a hydrous silicate of magnesia, is a fibrous form of serpentine, and often of silky fineness. Its fibres are formed at right angles to the direction of the fissures containing them. Chrysotile fibres, though short, have considerable strength and elasticity, and may be spun into threads and woven into cloth.

To bring the highest market price asbestos must needs have a combination of properties, i. e., length and fineness of fibre, tensile strength and flexibility-all combined with infusibility. Of these qualities the most important are toughness and infusibility, and determination of the same can only be made by practical tests or in the laboratory. Given several specimens of the same tensile strength and degree of

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infusibility, the one having the longest fibre will, of course, be of the greatest value. It must be kept in mind, however, that length of fibre alone, the characteristic which most naturally appeals to the eye, is not the final test in regard to the commercial value of the find; and much short fibre asbestos, which on first appearance is of inferior grade, is being sold and profitably handled at the present time.

The largest Canadian asbestos deposits are worked as open quarries where the ore is roughly sorted before being sent to the mill to be dressed for the market. This method has been found to be cheaper and more satisfactory in every way.

The milling of asbestos ore, while more or less complicated in actual practice, is easy to understand and has one well-defined object in view: That is, the complete eradication of all foreign rock ingredients and the thorough cleaning and separation of the fibres.

Asbestos, roughly speaking, is worth from $20 to $200 per ton. The poorer grades which are unsuitable for weaving, and which, of course, command the lower prices, are used in the manufacture of steam packing, furnace linings, asbestos brick, wall plasters, paints, tilings, asbestos board, insulating material, etc. The better grades are utilized in the manufacture of tapestries of various kinds, fireproof theater curtains, cloth, rope, etc.

A very important development of the asbestos industry is the rapidly increasing demand for the lower grade material, on account of the numerous diversified uses to which asbestos products are being put, in almost every branch of manufacture. This fact means that many deposits of asbestos will become commercially important even though the grade of the material is far from the best.

It has been discovered only recently that not only does an asbestos wall plaster render the wall so covered impervious to heat, but that in rooms which have given forth an undesirable echo this evil has been absolutely removed. Asbestos pulp mixed with cement and magnesite has been experimented with in the East; and roofing, flooring, and other building material of the most satisfactory sort has been manufactured therefrom.

The value of the domestic production of asbestos has averaged around $43,000 annually, the past ten years, except 1911, which was approximately $120,000. The imports, largely from Canada, for 1913 amounted to $1,928,705, according to U. S. G. S. Mineral Resources, 1913. This value is for crude material; adding the imported manufactured asbestos articles the figure amounts to $2,318,369.

With the field for development along these lines which is open in California, it seems almost certain that some time in the future will see this branch of the mineral industry adding its share to the total of the wealth and productiveness of this State.

Total amount and value of asbestos production in California since 1887, as given in the records of this Bureau, are as follows:

Bulletin 38.

Reference: State Mineralogist Report XII. The output of crude barytes during 1914 was 2,000 tons, valued at $3,000, as compared with the 1913 production of 1,600 tons, worth $3,680. This indicates a spot value of only $1.50 per ton for the 1914 product. As a matter of fact barytes is ordinarily sorted and ground before being put on the market, and in this prepared condition brings approximately $10 to $14 per ton. The principal use of this material is in the paint industry. Minor uses are in tanning of leather, manufacture of paper and rope, and sugar refining. A grinding and chemical plant has recently begun operations at Melrose, Alameda County, making a specialty of barium compounds.

Known occurrences of this mineral in California are located in Butte, Mariposa, San Bernardino, Shasta, Calaveras, Inyo, and Nevada counties. The deposit at El Portal, in Mariposa County, has given the largest commercial production to date.

Bauxite.

Reference: Bulletin 38.

No deposits of pure bauxite have been discovered in the State, although from time to time small quantities of the impure material have been the foundation of extravagant reports regarding such discoveries. In 1912 a company was incorporated and work of developing such a deposit was outlined, but close investigation proved the futility of such effort.

According to Bulletin 67 of this Bureau, bauxite of uncertain quality has been found at Smartsville, Yuba County.

Clay.

Reference: State Mineralogist Reports I, IV, IX, XII. Bulletin 38. At one time or another in the history of the State, pottery clay has been quarried in thirty-three of its counties. In this report "pottery clay" refers to all clays used in the manufacture of red and brown earthenware, flower pots, tiling of all descriptions, architectural terra cotta, sewer pipe, etc., and the figures for amount and value are relative to the crude material at the pit, without reference to whether the clay was sold in the crude form, or whether it was immediately used in the manufacture of any of the above finished products by the producer.

During 1914 producers in seven counties reported an output of 179,948 tons of clay, having a spot value of $167,552 for the crude material, as compared with the 1913 production of 231,179 tons worth $261,273.

A tabulation of the direct returns from the producers, by counties, for the year 1914 is shown herewith: