The relative geologic age of silver deposits is exhibited in the tabulation below:
| Probable future output (ounces) | Future percentage of total | Present proportion | |
|---|---|---|---|
| Tertiary | 170,000,000 | 76 | 73.0 |
| Japanese copper (largely Tertiary) | 5,000,000 | 2 | 3.1 |
| India and Australia (age of deposits not stated) | 25,000,000 | 11 | 9.45 |
| Pre-Cambrian | 15,000,000 | 7 | 9.45 |
| Unknown | 10,000,000 | 4 | 5.0 |
| Total | 225,000,000 | 100 | 100.0 |
Examination of the above data shows that by far the greater part of the world’s silver occurs in the great petrographic and metallographic province which forms a bordering zone around the Pacific Ocean, and is most productive in the western Cordilleras of North and South America.
CHANGES IN KNOWN GEO GRAPHICAL DISTRIBUTION IN THE NEAR FUTURE
Decreases may occur in Cobalt (Ontario) and in Japan; in Cobalt because of exhaustion of ore, in Japan because of lower output of copper and lead if prices of these metals fall. The Rocky Mountain-Andes output should be maintained relatively at the proportion shown above—Mexico being back to normal in this assumption. This Rocky Mountain-Andes production is all, or substantially all, associated with Tertiary igneous rocks.
The above figures allow in part for the increase in Indian output from the new Burma mines.
CHANGES IN PRACTICE
It is doubtful if silver production will be materially increased in the next few years by improvement in metallurgy, milling, or mining methods. Silver production is perhaps unique in that a great part of the output, produced as a by-product, comes on the market at a rate determined more by the volume of lead and copper production than by current quotations for silver. Also rich silver mines when discovered can be operated at a large profit per ounce. However, high prices for silver will stimulate that part of the production which comes from silver mines proper.
The world’s production increased over one-third during the period of 1904 to 1913. At the same time prices had declined even below the 1893-1894 figures. The increased output was due to production from the United States and from Canada.
Independent of price, the Cobalt discovery poured silver on the market. Independent of price, the increased lead and copper of the United States poured by-product silver on the market.