Placer platinum occurrences have been re ported from a wide variety of localities in British Columbia, but production has been limited to the Tulameen district, about ioomi. east and slightly north of Vancouver. A production of some 2,0000Z. annually in the 188o's declined to less than 5ooz. in recent years. Canada first came into an important position as a producer of the platinum metals after the establishment of electro lytic refining of nickel on a large scale and the development of methods of recovering the small amounts of the platinum metals associated with the nickel ores of the Sudbury district of Ontario. In the decade from 1929 to 1938 the Canadian output of platinum metals rose from 30,0000z. to 292,2000Z., 55% of which was platinum and 45% other metals of the group, chiefly palladium. Since 1934, Canada has been the leading producer of platinum group metals, though not in all years the leader in platinum alone. At the end of 1938 there were approximately 220,000,00o tons of nickel ore definitely blocked out in the Canadian nickel mines, but the average platinum content is not known; at the 1938 rate of recovery, this would represent over io,000,0000z. of platinum metals, more than half of which is platinum; even though it is questionable as to whether the entire amount of the reserves av erages as high in platinum metals as the current ore production, it is evident that there is an enormous potential supply, produc tion from which, however, will be determined primarily by the demand for nickel, rather than by the demand for platinum. On the other hand, being entirely a by-product, platinum from this source can be placed on the market at a lower cost than that from any other source.
Several hundred ounces of crude platinum have been recovered annually from gold placers in California, with smaller amounts from Oregon and occasionally other States, but by-product re covery from gold and copper refining has until recently accounted for the greater proportion of the United States output. As in California, there have been moderate recoveries from gold placers in Alaska, and in addition some recovery from placers worked primarily for their platinum content. Since 1934 platinum placers in the Goodnews bay district have expanded operations, and in 1938 reached an estimated output of 41,000oz. of crude platinum. This is the first year in which the United States has been able to produce a material percentage of her platinum requirements. No information is available on the extent of the reserves or their probable life, but in any case this area has been responsible for the first really material output of platinum in the United States.
America.----Platinum was first discovered in Colombia, and the gold-platinum alluvials of the upper San Juan river area supply a fairly large output, although this declined from the high of 70,0000z. reached in 1927 to less than 30,0000z. in 1938. Large areas of alluvial ground remain to be worked, but no recent data are available on the extent of the reserves. The gross value of the reserves does not seem to be suffering with continued working, but a progressive change extending back over several years, in volving an increase of gold content and a decrease of platinum content in the recoveries indicates a probable continuation of the decrease in output of platinum.
Since 1913 the United States has absorbed an average of 45% of the world's total output of new platinum, although during the past few years the proportion seems to have declined somewhat.
The United States figures will be used to illustrate the utiliza tion of platinum by various industries. The total consumption has varied from a low of 54,6000z. in 1932 to a high of 156,8000z. in 1922, and has averaged I14,50ooz., about two-thirds of which has been new metal, and one-third secondary metal, recovered from previous use. The bulk of the industrial consumption is not, as might be supposed, in the chemical and electrical industries; on the average, about 6o% of the total consumption has gone into jewellery; the chemical and electrical industries each have taken 13%, dental work 9%, and other uses 5%.
The consumption of palladium is much less than that of plati num, but has been growing, rising in a decade from less than 20, 0000Z. to 70,0000Z. in 1937; of this, dentistry took 40,0000z., electrical work 21,0000Z., and jewellery 8,000 ounces.
The demand for iridium usually ranges between 3,00o and 5, 0000z., although formerly it was somewhat higher. Jewellery is the chief consumer, with the electrical industry second. Uses for the other three metals of the group, rhodium, ruthenium, and osmium, are comparatively small, and no statistics are published.
Although the data on reserves are so scattered and incomplete that it is impossible to arrive at any estimate of the total, or their probable life, it is certain that the known reserves are sufficient to supply demand for many years to come, although it will require higher prices than prevailed from 193o to 1939 to bring much of this metal into the market, especially that from South Africa, unless there are improvements in technology re sulting in marked reductions in operating costs. (G. A. Ro.)