Ch. 1: Gold and Silver in 1911

Page of 105

Text size:



	GOLD AND SILVER.	235

	in a few instances platinum are recovered from gravels and sands, whether by hand-washing, sluicing, hydraulicking, drifting (in frozen ground or ancient buried river channels), or dredging. The deep mines are those producing gold and silver mainly from underground workings, including those whose ores are valuable chiefly for copper, lead, or zinc, but which contribute precious metals as by-products. In addition to the producing mines here enumerated, many mines were being prospected and developed without making an output in 1911, and annual assessment work (required by law to hold claims not patented) was done on a very much greater number of new or old, worked-out, or indefinitely idle properties, once productive or otherwise, and of mere mining claims, which have not yet become "mines.' The enumeration of placer mines is less satisfactory than that of deep mines, because some of the operations are only temporary' and because the production is frequently by transitory miners not regularly working placer ground. The unit, so far as possible is, however, as for deep mines, not the operator, but the mining claim, or group of claims. Number of producing mines in 1911, by States and Territories.¹¹



	o Illinois, Kentucky, Philippines, and Porto Rico not included, b Number of mines'contributing to silver production in 1911. The table shows the number and distribution of mines producing gold and silver in the United States and Alaska. With the exception of (1) some of the Michigan copper mines, (2) all zinc mines in the Eastern and Central States and a few in the far West, and (3) all lead mines of the Central States (except a few in Illinois and southeastern Missouri), practically all mines producing copper, lead, and zinc in the United States and Alaska yield gold and silver also. The table, therefore, with these exceptions, is a table of mines producing gold, silver, copper, lead, and zinc in the United States. It also includes certain mines producing oxidized manganese-iron fluxing ores of Colorado, Utah, and elsewhere, whose ores contain small quantities of precious metals, especially silver, and are sold to western smelters as flux. Comparisons with corresponding figures for 1910 show a net total increase of 374 producing mines in 1911. The number of deep mines increased by 254 and the number of placers by 120. In 1910 the

Page of 105