Ch. 1: Gold and Silver in 1914

Page of 97

Text size:



	862	MINERAL RESOURCES, 1914----PART I.

	From this table the output of ore from the Central States, producing small quantities of silver and no gold, has been omitted. The output of zinc or© from the Eastern States is also omitted, as this zinc ore is reported to produce neither silver nor gold. The following table shows in summary the percentage of total output, by processes, of gold and silver in 1912, 1913, and 1914: Percentage of output of gold and silver by processes in the United States in 1912, 1913, and 1914.



	The placers produced one-fourth of the total output of gold and, in percentage, show a small but steady increase during the last three years, owing both to slight decrease in some of the large lode mines and to an increased yield by dredging. The percentage of output of silver credited to the placers is insignificant. In the mills the amalgamation process has given steadily decreasing production of gold and silver, the chlorination process has almost ceased to produce gold, but the cyanidation process each year has given increased proportion of the total production of both gold and silver. Altogether the mills show a proportionate decrease in gold and an increase in silver, and in 1914 they produced 52.5 per cent and 22.5 per cent of gold and silver, respectively. The smelters have been producing each year a slightly greater proportion of gold and a smaller proportion of silver and are to be credited in 1914 with 22.2 per cent of the total output of gold and 77.3 per cent of the silver. The- bulk of the output of silver, however, is still from the smelting of crude ore, concentrates, and other material, but in decreasing ratio as the ratio of output from cyanidation increases. The bulk of the gold output is also mainly still from the gold mills, but in decreasing proportion, for although the output from cyanidation increases it does not offset the decrease by amalgamation and chlorination and the increase from placers and from the smelting of crude ores and concentrates. The following table shows in greater detail the ore treated and the output of gold and silver mills, by States, in 1914:

Page of 97