U. S. Geological Survey, Washington, D. C., or to Room 305, U. S. Custom House, San Francisco, Cal., for a copy of the "separate" on the subject. "There was a decrease in California in 1915 in the number of productive mines, but an increase in yield of gold, silver, copper, lead and zinc. * * * In 1915 there were 608 properties reporting production, of which 321 were "deep" (vein) mines and 287 were placers. The producing deep mines of 1915 may be classified by metallic product as follows: Gold, 237; copper, 43; silver, 11; silver-lead, 3; lead, 21; and zinc, 6. Of the placer mines, 96 were hydraulic; 58 were dredge; 61 were drift; and 73 were surface or sluicing. * ** * "The siliceous ore yielded an average per ton in gold and silver of $5.68; the copper ore, $1.71; the silver ore, $63.77; the lead ore, $6.85; the silver-lead ore, $64.32; and the zinc ore, $3.09. The average per ton in gold and silver from all ores treated in the state in 1915 was $4.89. "The 3,002,779 tons of ore of all classes treated in California in 1915 yielded 669,204.22 fine ounces of gold, valued at $13,833,679; 1,640,888 fine ounces of silver, valued at $831,930; 40,751,625 pounds of copper, valued at $7,131,534; 4,579,245 pounds of lead, valued at $215,225; and 13,094,032 pounds of zinc, valued at $1,623,660. "The total production of gold in California in 1915 was 1,085,646.05 fine ounces, valued at $22,442,296, as compared with 999,112.85 fine ounces, valued at $20,653,496 in 1914, * * * or 8.66% increase for 1915. * * * Of the deep mine gold, 644,044.19 fine ounces, valued at $13,313,575 was derived from siliceous ores; 23,797.60 fine ounces, valued at $491,940, was derived from copper ore; 1,110.26 fine ounces, valued at $22,951, from lead ore; 95.98 fine ounces, valued at $1,984, from silver ore; 29.21 fine ounces, valued at $604, from silver-lead ores; and 126.98 fine ounces, valued at $2,625, from zinc ores. "The placer yield of gold in 1915 was 416,441.83 fine ounces, valued at $8,608,617. Of this, $420,770 was derived from 96 hydraulic mines; $7,796,465 from 58 dredges; $272,955 from 61 drift mines; and $118,427 from 72 surface or sluicing mines. The placer mines produced 38.36% of the total gold yield for 1915, and the deep mines 61.64% as compared with 43.97% for the placers and 56.03% for the deep mines in 1914. The dredges produced 34.74% of the total gold yield from all sources in 1915, and 90.57% of the total placer gold. The hydraulic mines produced 4.89% of the total placer gold for the year. "The largest production of gold in California in 1915 came from Amador County. The leading hydraulic mining county was Siskiyou; the greatest producer of gold from drift mines was Placer; the largest producer of gold from dredges was Yuba; and the largest producer from surface or sluicing mines was Butte. The largest increase in total yield of gold in 1915, as compared with 1914, was in Amador, an increase of $812,123"; followed by Kern, El Dorado and Mariposa in the order named, each with an increase in excess of a quarter of a million. The gold production of California for 1915 was distributed, by counties, as follows: The following table was compiled by Chas. G. Yale, of the Division of Mineral Resources, U. S. Geological Survey, but for a number of years statistician of the California State Mining Bureau and the U. S. Mint at San Francisco. The authorities chosen for certain periods were: J. D. Whitney, state geologist of California; John Arthur Phillips, author of "Mining and Metallurgy of Gold and Silver" (1867); U. S. Mining Commissioner R. W. Raymond; U. S. Mining Commissioner J. Ross Browne; Wm. P. Blake, Commissioner from California to the Paris Exposition, where he made a report on "Precious Metals" (1867); John J. Valentine, author for many years of the annual report on precious metals published by Wells Fargo & Company's Express; and Louis A. Garnett, in the early days manager of the San Francisco refinery, where records of gold receipts and shipments were kept. Mr. Yale obtained other data from the reports of the director of the U. S. Mint and the director of the U. S. Geological Survey. The authorities referred to, who were alive at the time of the original compilation of this table in 1894, were all consulted in person or by letter by Mr. Yale with reference to the correctness of their published data, and the final table quoted was then made up. The figures of the last eleven years are those prepared by the U. S. Geological Survey: Bibliography: State Mineralogist Reports II, IV, V, X, XII, XIII. Iron ore to the extent of 724 tons, valued at $2,584, was produced in California during the year 1915. It was utilized in the production of ferro-manganese and ferro-chrome by electric furnace reduction. There are considerable deposits of iron ore known in California, notably in Shasta, Madera and San Bernardino counties, but production has never amounted to much, on account of our having no economic supply of coking coal. Developments along the line of electrical smelting, or discoveries making valuable our petroleum fuel, would lead to considerable increase of iron mining in California. Total iron ore production in the state, with annual amounts and values, is as follows: Bibliography: State Mineralogist Reports IV, VIII, X. Lead was produced during 1915, to the extent of 4,796,299 pounds, which at 4.7¢ per pound was valued at $225,426, being an increase both in amount and value as compared to the previous year. The principal yield comes from Inyo County, followed by Shasta, San Bernardino and Kern in the order named. The ores are mined and shipped to smelters. On account of the European war, the price increased from the 3.9¢ per pound average of 1914, to 4.7¢ as noted above. County returns for 1915, showing amounts and values, were: Statistics on lead production in California were first compiled by this Bureau in 1887. Amount and value of the output, annually, with total figures, to date, are given in the following table: $3,960 5,270 25,083 16,690 46,663 225,426 MANGANESE. Bibliography: State Mineralogist Reports XII, XIII. Bulletins 38, 67; U. S. G. S., Bull. 427. In the statistical reports of 1913 and 1914, manganese ore was included in the "industrial materials" list. We have this year made a transfer, and now place it under "metals," because by far the greater tonnage of manganese ore is utilized in the preparation of ferromanganese and employed in the steel industry for its metal content. Though its other uses may be classed as "chemical," the tonnage thus consumed is relatively smaller. Its chemical uses are as a decolorizer or oxidizer in glass manufacture, and as a constituent in electric dry batteries. The chemical uses require a much higher grade of ore than the steel industry. For steel purposes, an iron content is acceptable, but manganese should exceed 40%. Silica should be under 8%, though higher has been taken during the present scarcity of foreign supplies. Phosphorus should be under 0.20%. For electric dry cells, the iron content should be under 1.5%, Fe2O3, and SiO2 under 6%. For glass making, the manganese should be practically free of iron. The bulk of the 1915 product was utilized in California in making ferro-manganese by electric furnace, though some of the year's output was sent east. Some "chemical" ore was shipped in 1915 from Mendocino County, and shipments are also at present being made from a mine in San Bernardino County. For many years the principal producing section has been the Livermore-Tesla district, in Alameda and San Joaquin counties, although exceeded in 1915 by Mendocino. Manganese is reported to exist in many localities in the state; but past pro |