Jack,
I HAVE PREPARED THESE REPORTS SO THAT YOU CAN SEE SOME OF THE EFFORT THAT HAS BEEN SPENT OVER THE YEARS BY THE UNITED STATES TO DEVELOP A SUPPLY OF PLATINUM-GROUP METALS. THIS FIRST REPORT IS FROM THE 1900 ANNUAL REPORT THE MINERAL RESOURCES OF THE UNITED STATES, PREPARED BY THE UNITED STATES GEOLOGICAL SURVEY.
The platinum produced in the United States during 1900 was all obtained from gold placer deposits, chiefly those in Trinity and Shasta counties Cal. and amounted to 400 ounces valued at $2,500. Ever since this metal began to be found in the gold placer deposits of California miners and prospectors have hoped to obtain it in quantity, but thus far it has been obtained only as a secondary product in gold mining. Since 1880, the first year in which a record was obtained, the largest amount of platinum produced in one year was in 1890, when 600 ounces, valued at $2,500, were produced. In 189S, although only ounces were produced they were valued at $3,375. This variation in the value is due to the quality of the crude grains of platinum. The demand that arose during 1898 for the metal osmium, which was wanted for the manufacture of a new incandescent light, led to a thorough examination by Dr. David T. Day of the localities where platinum had been found or was reported to occur, this being done principally to determine whether the metal desired was contained in the crude platinum found in these localities. During this investigation samples of heavy sand were examined from placer mines in California, Oregon, Washington, Idaho, Montana, and Alaska. As a result of this examination, platinum has been shown to occur in minute quantities at many of the placer mines in California and Oregon and at a few places in Idaho, Montana, and Alaska. It was only in the placer deposits in Plumas, Shasta, Trinity, and Siskiyou counties, Cal., that the metal was found in quantity. It is a noteworthy fact that chromite is nearly always found associated with the platinum, and that in many of the mountain ranges in which the streams have their head there are extensive serpentine formations which contain chromite. Wherever platinum has been found in place it has been associated with chromite and disseminated through a basic magnesian rock of which serpentine is a common alteration product. It is not unreasonable to suppose that platinum will be found in California and Oregon "in situ" associated with chromite in the basic magnesian formations of these States. Again, it is not improbable that platinum will be found in the eastern part of the United States in the basic magnesium rock peridotite, which occurs extensively developed in North Carolina, Georgia, Pennsylvania, and Maryland, and which has in nearly all cases chromite associated with it. Platinum in the form of sperrylite, a platinum arsenide, has been found in minute quantities at several places in the placers of Cowee Valley and Mason Valley, Macon County, N. C. There is, however, no authenticated record of any native platinum having been found in these States. Platinum was recently reported to have been found in the mines of the gold placer deposits at Esineraldas, Ecuador. An analysis of this platinum showed the presence of 1.54 per cent of osmiridium. As is seen from the following table, which shows the production of platinum in the United States since 1880, there has been but little added to the worlds production of this metal.
THIS NEXT ARTICLE IS FROM THE GEOLOGICAL RELATIONS AND DISTRIBUTION OF PLATINUM AND ASSOCIATED METALS, USGS BULLETIN 193 (1902)
Arizona
Specimens of a shaly rock have been sent to the East from some locality near Williams, Arizona, which have yielded assays for platinum. The clays in Cataract Canyon, a branch of the Grand Canyon, are also said to contain platinum.
THIS NEXT ARTICLE IS FROM ECONOMIC GEOLOGY OF THE PLATINUM METALS, GEOLOGICAL SURVEY PROFESSIONAL PAPER 630 (1969) ARIZONA IS NOT MENTIONED BUT A SMALL MINE IN NEVADA IS.
The Boss mine is in the Yellow Pine mining dis-trict, of Clark County, Nev. This ore deposit was dis-covered about 1886 and was worked intermittently for copper and gold for 28 years. Platinum was discovered in 1914, and thereafter the mine was worked until 1919. The Boss deposit was an ore shoot of ellipsoidal shape which followed the hanging wall of a fault zone in thick-bedded limestone of Mississippian age. The deposit is not cut by granitic rocks, but a granitic dike appears about 1,500 feet northeast of the mine.
The ore body, from the available descriptions, ap-pears to have been an ellipsoidal ore shoot with a length of about 200 feet and a maximum width of about 25 feet; smaller bodies are also recorded. The ore minerals consisted of dark cellular masses of quartz that con-tained chrysocolla, limonite, and local concentrations of chalcopyrite, bornite, chalcocite, malachite, and cuprite. Within the ore body were stratified masses and nar-row veins of plumbojarosite which was determined by earlier observers to be the source of the precious metals. A sample of this talclike material, collected by Adolph Knopf (1915, p. 878), was analyzed by F. C. Wells, of the U.S. Geological Survey; but the material was afterwards determined by W. T. Schaller, of the U.S. Geological Survey, to have been a mixture of plumbo-jarosite, beaverite, and bismutite. Hence, the analysis is of value mainly for the tenors of platinum and palladium that were determined. The stated values show that for such picked ore the tenors of platinum and palladium per ton of ore were respectively 14.6 and 64.2 troy ounces.
The tenors of the platinum ore and crude ore that was mined, however, are much smaller. One assay by Hale (1914) and two other sets of data published by Hewett (1931) bear upon this question. From Hewett's data, one can obtain the weighted mean values of the smelter returns on the "platinum ore" for 1916-19, and the weighted mean tenors of the crude ore for 1917-19. These three values are given herewith:
Hale: 0.5 to 1.0 ounce platinum per ton of ore.
Hewett: 0.32 ounce platinum and 1.10 ounces palladium per ton of "platinum ore."
Hewett: 0.05 ounce platinum and 0.11 ounce palladium per ton of crude ore, or 0.16 ounce platinum metals per ton.
The ratio of platinum to palladium, as gaged by the analysis made by the U.S. Geological Survey, was 1:4.4. The same ratio as gaged by Hewett's smelter returns was 1:3.5.
The mode of occurrence of the platinum and pal-ladium in the plumbojarosite has not been determined. It was suggested by Knopf (1915a, p.8) that the min-eral sperrylite might be present, but this idea was properly rejected by Hewett. Moreover, the platinum--palladium ratio of approximately 1 :4 does not fit with this interpretation. From what is now known of the numerous platinum minerals as earlier stated in this report, it is probable that the platinum and pal-ladium exist as separate minerals in the sulfides or other metallic minerals of the ore.
The Boss mine is frequently cited as an unusual occurrence of the platinum metals in a quartz vein. This deposit, however, is not unique in this respect, as the same or similar associations have been recorded at many other places in the world. Among the better known of these are the following:
1. Gold Hill mine, of the Gold Hill quadrangle, Oregon.
2. Quartz veins in West Point mining district, Cal-averas County, Caif.
3. Gold quartz vein at property of Roll Call Mining Co., near Villa Grove, Calif.
4. Quartz vein near Boyerstown, Pa.
5. Gold quartz vein at Mother Lode claim, Burnt Basin, 3 miles west of Coryell, Yale district, British Columbia.
6. Quartz vein in granodiorite in Ainsworth mining district, British Columbia.
7. Gold quartz vein in Union Mine, Grand Forks division, British Columbia.
8. Gold quartz vein at mine of Northern Manitoba and Development Co., near The Pas, Manitoba.
9. Quinn claims near the Croesus mine, Munro Township, Ontario.
10. Gold quartz veins in Halifax County Nova Scotia.
11. Guadalcanal, a few miles northeast of Rio Tinto district, Spain.
12. Near Chatelard, Vallee du Drac, Haute Alpes, France.
13. Quartz veins in Thames gold field, North Island, New Zealand.
14. Quartz veins of Hauraki district, North Island, New Zealand.
15. Massive pyrite at Coromandel, North Island, New Zealand.
16. Quartz veins in ultrabasic rocks, North Westland, South Island, New Zealand.
17. Quartz veins associated with serpentine, Tere-makau River, South Island, New Zealand.
18. Quartz veins in Lucknow and Alma auriferous reefs, at Gympie, New South Wales.
19. Boa Esperanca veins, Minas Gerais, Brazil.
20. Santa Rosa, north of Medellin, Antioquia, Colombia.
21. Quartz veins of the Waterberg district, Republic of South Africa.
22. Platinum-bearing gold quartz veins of Beresovsk district, Ural Mountains.
23. Quartz veins of northern Finland
None of these deposits, however, is an important source rock of the platinum metals. They show merely that the platinum metals are not restricted to ultra-basic and basic rocks.
The authenticity of some of the occurrences quoted above may be questioned, particularly at sites where native platinum alloys have been found. It is well known to placer miners that the precious metals at the base of many placers have penetrated downward for 10 to 20 feet into shattered bedrock. If it should happen that the bedrock below a placer consisted of vein quartz, which is brittle and readily shattered, native gold and platinum could, readily penetrate into such rock and form an ore body that simulated a gold-plati-num lode. The fact that such a lode is far removed from any present stream is immaterial.
THIS NEXT ARTICLE IS MINERAL AND WATER RESOURCES OF ARIZONA, PREPARED BY THE UNITED STATES GEOLOGICAL SURVEY, THE ARIZONA BUREAU OF MINES, AND THE UNITED STATES BUREAU OF RECLAMATION BULLETIN 180 (1969)
Only a few occurrences of platinum-group metals have been re-ported in Arizona. These occurrences, however, are doubtful and the potential for finding platinum-group metals in Arizona is poor. Two small periidotite bodies occur in association with other lower Precam-brian rocks in northeastern Maricopa County (Wilson and others, 1957), but no platinum-group metals have been found in them. About 1900, the discovery of large platinum deposits in the region of Cataract Canyon on the Colorado was announced but could not be verified (Blake, 1900). Several years later persistent reports of an occurrence near Indian Garden in the Grand Canyon led to several detailed examinations of the area by F. L. Ransome and H. G. Ferguson, and, though special care in sampling and assaying was used, no platinum was detected (Mining Sci. Press, 1919). Occurrences of platinum also have been reported in the San Domingo placers in Maricopa County, and near Prescott and near Columbia in Yavapai County (Galbraith and Brennan, 1959, p.5). Columbia was a village on Humbug Creek west of the Tip Top mine and town (Granger, 1960, p.339). However, no record of platinum production from these areas has been found, nor is there any record of platinum having been paid for by buyers of gold from Arizona.
Erroneous reports of the presence of platinum-group metals often stem from the difficulties in detecting them. Assay for platinum and palladium, even for amounts that would constitute ore, is much more difficult than for gold. The other four metals in the group are even more difficult to determine. Even reliable and experienced assayers have been deceived into reporting nonexistent platinum. On the other hand, it is not likely to be missed if present and looked for. A new method for the determination of low concentrations of palladium, platinum, and rhodium (Haifty and Riley, 1968) may help alleviate this problem.
A number of metals and minerals have been mistaken for platinum--group metals due to some of their properties. Among them are "chilled" birdshot (lead alloyed with arsenic), lead fragments from other sources, specular hematite in small flakes, and old amalgam. Any of these materials may be found in some panned concentrates, and if the sample has been roasted in the presence of carbon, metallic iron or other metals may have been formed. All of these materials may be surprisingly resistant to acid tests and even some gold-silver alloys are nearly insoluble in aqua regia.
Because of the difficulty in detecting the platinum-group metals and because of their probable scarcity in Arizona and elsewhere, caution is advised in accepting any unconfirmed reports of their presence.
THIS LAST ARTICLE IS FROM MINERALOGY OF ARIZONA
Platinum
Platinum, Pt. A rare mineral mostly restricted to ultramafic rocks, their metamorphic equivalents, and placers derived from them. The localities listed below have not been recently verified.
Maricopa County: Reported in the Santo Domingo placers, along the Gila River, opposite the old Riverside Stage station.
Yavapai County: Reported in black sands near Columbia and Prescott (Guild, 1910).
IN CONCLUSION ALL I CAN SAY IS, I WOULD LIKE TO SEE A COPY OF WHAT EVER INFORMATION GLOBAL HAS ABOUT PLATINUM PRODUCTION FROM THE ORO GRANDE.
Tim |
