* *

“The yield of silver in California in 1915 was 1,678,756 fine ounces, valued at $851,129, an increase in quantity of 206,897 ounces and an increase of $37,191 in value. The larger portion of the output, 1,445,037 ounces, valued at $732,634, was derived from crude smelting ores. The output of siliceous ore, both milled and smelted, yielded 272,849 fine ounces, valued at $138,334. The largest output of silver came, as usual, from Shasta County, which produced * a total of 906,441 fine ounces, valued at $459,566," mainly from copper ores, with smaller amounts from siliceous ores and placers. "Inyo County followed Shasta in yield of silver in 1915, the output being 252,257 ounces, valued at $127,894, * * * nearly equally divided between lead ores and zinc ores. The total silver derived from deep mines of all classes in California in 1915 was 1,640,888 ounces, valued at $831,930. The silver obtained with gold in placer mining in the state in 1915 was 37,868 ounces, valued at $19,199. The largest producer of placer silver was Yuba County, with 10,357 ounces, valued at $5,251."

The distribution of the 1915 silver yield, by counties, was as follows:

*Combined to conceal output of a single property in each.

The value of the silver produced in California each year since 1887, is as follows:

TIN.

Bibliography: Bulletin 67, "Cassiterite."

Tin is not at present produced in California; but during 1891–2, there was some production from a small deposit near Corona, in Riverside County, as tabulated below. Small quantities of stream tin have been found in some of the placer workings in northern California, but never in paying amounts.

Early in the current year, two new occurrences have been noted in northern San Diego County. Crystals of cassiterite have been found there, associated with blue tourmaline crystals, amblygonite and beryl. No commercial quantity has been developed, only small pockets having been taken out, as yet; but the prospect is an interesting one. Total output of tin in California:

The metal, tungsten, is used mainly in the steel industry and in the manufacture of electrical appliances, including the well-known tungsten filament lamps. Because of its resistance to corrosion by acids, it is valuable in making certain forms of chemical apparatus. In the form of tungstic acid, it is stated to be used to toughen silk and linen fabrics for certain purposes.

Tungsten ore is produced in California principally in the AtoliaRandsburg district in San Bernardino and Kern counties, with small amounts coming from Nevada County and from the district near Goffs, in eastern San Bernardino. Most of the California tungsten ore is scheelite (calcium tungstate), though wolframite (iron-manganese tungstate) and hübnerite (manganese tungstate) also occur. The value of the ore is based upon the content of tungstic trioxide (W O3), and quotations are commonly made per unit (each 1%) of W O present.

In 1915 there were marketed 962 tons of high grade ore and concentrates, valued at $1,005,467, which is more than double the tonnage and over five times the value of the 1914 output. Previous to 1915, a single company produced almost all of California's tungsten. During the latter part of 1915, and the early months of 1916, because of.

the high prices prevailing, prospecting was much stimulated, and the known tungsten-bearing areas have been considerably extended both in San Bernardino and Kern counties. Shipments have also begun from mines opened up in the Clark Mountain and New York Mountains districts in eastern San Bernardino County. In these latter areas, wolframite and hübnerite are the principal ores, with some scheelite, while at Atolia it is scheelite only. Scheelite ore is also being developed in Inyo County near Bishop, and two concentrating mills are under construction. The Nevada County ore is also scheelite. Distribution of the 1915 output was as follows:

*Combined to conceal output of a single mine in Nevada County.

The annual value of tungsten produced in California since the inception of the industry is given herewith:

No commercial production of vanadium has as yet been made in California. Occurrences of this metal have been found near Goffs in San Bernardino County, and two companies have done considerable development work recently in the endeavor to open up paying quantities. One mill has been built, and another is under construction. Ore carrying the mineral cuprodescloizite and reported as assaying 4% V2O, is being developed at Camp Signal, near Goffs. There is a growing demand for vanadium, for use in the steel industry.

ZINC.

Bibliography: Bulletins 38, 67.

Zine was produced in Shasta, Inyo and San Bernardino counties during 1915, to the amount of 13,043,411 pounds, valued at $1,617,383. This is an unprecedented increase both in tonnage and value over any previous year, and is due mainly to the stimulation of the market, chargeable to the European war. The average price for the year was 14.2¢ per pound, as compared to 5.1¢ during 1914.

The zinc ores of Shasta County are associated with copper, while those of Inyo and San Bernardino are associated with lead-silver ores. The ores are shipped to eastern smelters for treatment. The production, by counties, was as follows:

Total figures for zinc output of the state are as follows:

CHAPTER FOUR.

STRUCTURAL MATERIALS.

As indicated by this chapter heading, the mineral substances herein considered are those more or less directly used in building and structural work. California is independent, so far as these are concerned, and almost any reasonable construction can be made with materials produced in the state. This branch of the mineral industry for 1915 was valued at $13,481,947, as compared with a total value of $14,469,982 for the year 1914. Only a few years ago its value was of no significance in considering the total mineral production of the state. With the growth, in population and otherwise, of California, this subdivision of the mineral industry in the state will increase indefinitely. Deposits of granite, marble and other building stones are distributed widely throughout the state, and slowly but surely transportation and other facilities are being extended so that the growing demand may be met. The largest single item, cement, has an unparalleled record of growth since the inception of the industry in California twenty-four years ago. Not until 1904 did the annual value of cement produced reach the million-dollar mark, following which it increased 500 per cent in nine years; though the last two years it has declined slightly.

Crushed rock production is yearly becoming more worthy of consideration, due to the strides recently taken in concrete building, as well as to activity in the building of good roads. Brick, with an annual output worth nearly $2,000,000, is slowly decreasing, due to the popularity of cement and concrete; nevertheless, this item will be an important one for many years to come, and of course, a market for fire and fancy brick of all kinds will never be lacking.

The following table gives the comparative figures for the value of structural materials produced in California during the years 1914 and 1915. Fifty-one counties contributed to this total, and there is not a county in the state which is not capable of some output of at least one of the following classes of material: