output has thus been curtailed for the last two years by unsettled political conditions, and the Lake Superior output was greatly reduced in 1913 by labor conditions. Such conditions can be almost relied upon to keep the output somewhat below the real producing capacity. It seems very doubtful, however, if it will be feasible for all the mines of the world to produce at their maximum capacity for the next few years.

There will be no large producers added in 1914, but those already active will be able to increase the output considerably if there is a demand for the metal. It seems doubtful, however, if the demand will warrant a very large increase in 1914.

GEOLOGIC CLASSIFICATION OF COPPER DEPOSITS.

BASIS OF CLASSIFICATION.

The geologic classification of copper ores is of interest as well as the metallurgical classification. From a statistical standpoint, such a classification is somewhat difficult for the reason that in a single district two or more types may occur and in some instances the amount of copper derived from each has not been recorded. The approximate amount derived from the several types can, however, usually be ascertained.

It is apparent that in a statistical treatment only broad groups can be recognized, as the data are not available for ascertaining the output from types of minor commercial importance, although they may be of great scientific interest.

A classification may be made on the basis of the geologic age of the deposits, which is usually the same for all deposits in a given district, which method groups together deposits differing greatly in mineralogic character and geologic occurrence; or, on the other hand, a classification may be based on geologic occurrence and mineralogic character by which method deposits of widely separated ages are thrown into the same group.

In the following tables is given the production classified according to the geologic age of the deposits and according to geologic occurrence. The basis of these classifications is discussed in the reports for 1910 and 1912.

Classification of production of copper according to geologic age of the deposits.

Classification of production of copper according to geologic age of the deposits-Contd.

Classification of production of copper according to geologic occurrence of the ores.

The production of copper in 1913 by smelters from copper-bearing materials from the United States was 1,224,484,098 pounds, valued at $189,795,035,' as compared with 1,243,268,720 pounds, valued at $205,139,338, in 1912, and with 1,097,232,749 pounds, valued at $137,154,092, in 1911. The production for 1913 showed a decrease from the previous year of 18,784,622 pounds, or about 1.5 per cent in quantity and $15,344,303, or 7.43 per cent in value.

1 For discussion of prices see section on prices on a subsequent page.

The yearly production of copper in the United States from 1845 to 1913, inclusive, together with the actual and relative changes from each preceding year, is shown in the following table:

Magnitude and growth of copper production in the United States from 1845 to 1913, inclusive.

The figures, except for 1913, are taken from the previous volumes. of Mineral Resources of the United States. Statistics from 1882 to 1913, inclusive, are based on the returns to the United States Geological Survey by the copper-producing companies. Figures for the years prior to 1882 were compiled by the Survey from the best sources available. Reliable figures for years previous to 1845 are not obtainable. The year 1845, however, marks the entrance of the Lake Superior district into the ranks of producers and is really the beginning of important production of copper in this country. The industry has shown a steady and, since 1880 when Arizona and Montana became important producers, a very rapid growth.

Only six times since 1880 has the annual production shown a decrease from that of the preceding year and in every instance the decrease has been slight and has been more than recovered the following year. The years showing a decrease are 1886, 1893, 1901, 1907, 1910, and 1913. At several other times the increase has been slight. In most years when there has been a decrease it may be attributed to a general condition of financial and business depression, which has resulted in a decrease in the demand for copper and other materials necessary to the expansion of industries. In three years a slight decrease appears to have been due to the fact that the producing capacity of the country had been increased out of proportion to the demand for domestic consumption and export, and a temporary curtailment in production became necessary to permit the absorption of accumulated stocks. This, coupled with attempts at artificial control of prices, appears to have been the case in 1886 and also in 1901, and the decrease in production in 1910 may be attributed to a similar cause. The large increase in 1912 which, with one exception, that of 1909, was the largest in the history of the industry, was due to the output from mines that have reached the producing stage during 1912 or had previously made but relatively small production.

The decrease in 1913 is more than equaled by the falling off in Michigan due to labor troubles. Montana also showed a notable decrease, which was more than made up by notable increases in Arizona, New Mexico, and Utah.

So far as the producing capacity of the country is concerned, a substantial increase is possible for 1914, though the Michigan output for that year will be considerably below normal. Whether or not such an increase is made, depends on the demand for domestic consumption and export.

SMELTER RETURNS.

The figures of smelter production for 1913 are based on returns made confidentially to the United States Geological Survey by all known smelting companies handling copper-bearing materials from the United States. To all companies and officials who have aided in furnishing this information and have given valuable time to answering inquiries to secure the accurate distribution of the output sincere thanks are extended. The following list gives the names of the owning or operating companies, the location, and the final copper product of smelting and refining plants treating material from the 63057° -M R 1913-VOL 1 -34

United States during 1913. It does not include lead and zinc plants that recovered copper as a by-product from mixed ores. Lists of lead and zinc smelters can be found in the reports on those metals.

Copper smelting plants that treated materials from the United States in 1913.

a This list does not include a smelter in New Jersey and one in Pennsylvania, both of which make blister from material solely of foreign origin.