Ch. 1: Gold and Silver in 1912

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	252	MINERAL RESOURCES, 1912.

	ville, Tintic, and Chewelah districts in the United States. The relatively low silver content of the Clifton, Ray, and Ely copper ores, and especially of the Santa Rita (Chino) copper ores, is also notable.

	DISTRIBUTION OF GOLD PRODUCTION OF 1912, BY SOURCES. As shown in the following tables, the great bulk of the gold output is from dry or siliceous ores—normally gold-quartz ores—and placers, about 92 per cent of the total gold production coming from these two sources alone. The total output of gold derived from the great copper, lead, and zinc mines of the United States is therefore comparatively small. The changes in relative output from the various sources given in the table have been unimportant during the last three years. It is interesting to note, however, the gradual increase in relative placer output from 23.76 per cent in 1910, to 24.17 per cent in 1911, and to 24.94 per cent in 1912, also corresponding decreases in relative output from dry or siliceous ores from 68.91 per cent in 1910 to 68.52 per cent in 1911, and to 67.29 per cent in 1912. Normally, changes would be expected in the opposite direction. The following table shows the sources by classes of ore, by States, of the gold production of 1912, and for comparison the corresponding figures for 1911 are given: Source of gold in 1912 in States and Territories, as reported from the mines to the United States Geological Survey, by hinds of ore and by States, in fine ounces."

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