GEOLOGICAL AND GEOGRAPHICAL DISTRIBUTION
Peruvian Deposits.
—The largest deposits of vanadium in the world, and the most important, were until recently controlled by the American Vanadium Co. of Pittsburgh, Pennsylvania, which in 1919 was absorbed by the Vanadium Products Corporation, allied to the Bethlehem Steel Corporation. These deposits are at Minasragra, Peru, 20 miles from Cerro de Pasco. The area lies along the western limit of a broad anticline in Juratrias and Cretaceous rocks. A section shows the series in this locality to be composed of green shales, thin beds of limestone, and red shales. Vanadium is found only in the red shales. The deposit proper appears to be a lens-shaped mass, 28 feet wide and 350 feet long. The ore contains several minerals. The mineral that constitutes the large portion of the deposit is called “quisqueite”; it is a black carbonaceous substance containing sulphur. There is also a lesser quantity of a coke-like material. Neither of these contains vanadium. The vanadium is mostly at the southern end of the ore body, and to a depth of 20 feet is largely in the form of red calcium vanadate, which is brighter colored then the calcium vanadate in Colorado and Utah, and carries as much as 50 per cent. vanadium oxide. It occurs in small pockets and fills the cracks and fissures in a fine shale. Below this shale is the “mother lode,” which is 9 to 30 feet thick, extends along the greater length of the deposit, and carries as high as 10 per cent. vanadium oxide and nearly as much sulphur. On the east and south sides, below the “mother lode,” is a hard blue-black vanadium shale, carrying as much as 13 per cent. vanadium oxide and 4 to 5 per cent. sulphur. Patronite, the main vanadium mineral, is greenish black and contains 19 to 24.8 per cent. vanadium oxide and in places 50 to 55 per cent. of combined sulphur. The patronite originally almost reached the surface and is most abundant in the north half of the lens. The whole ore body is almost completely inclosed by porphyry dikes and contains two or three intrusions. These deposits are controlled by the American Vanadium Co., and its successor, the Vanadium Products Corporation, through a concession from the Peruvian government. They are large, but are by no means inexhaustible, and as they are entirely local they are not likely to be duplicated. No similar deposits are known, either in Peru or in any other part of the world.
In 1917 the American Vanadium Co. treated 5,236 gross tons of ore, from which it extracted 2,122,005 pounds of vanadic acid. From this vanadic acid the company manufactured 4,925,014 pounds of ferrovanadium. The company did not buy any ore in this country, but relied entirely upon its Peruvian production.
Other Foreign Deposits.
—The deposits in Peru are the only deposits of any commercial importance outside of the United States. Vanadium is found in South Australia, associated with carnotite and other uranium minerals. Small quantities of vanadic oxide are obtained as a by-product in the treatment of these ores.
Vanadium is also associated with uranium minerals in the Andijan district, Central Asiatic Russia. The vanadium is usually found as turanite, or copper vanadate; ferganite, an ortho-vanadate of uranium; and as several other new minerals. The amount of ore seems to be reasonably large, and this district may ultimately become a source of both uranium and vanadium.
The lead ores of Mexico contain some vanadium, the best known deposits being in the northeastern part of the State of Chihuahua. Other deposits are reported in Zacatecas, Guanajuato, San Luis Potosi, and Hidalgo.
Deposits in the United States.
—The principal vanadium deposits of the United States occur in a metallographic province covering southern and southwestern Colorado, southeastern Utah, and parts of Arizona and New Mexico. Uranium and radium characterize the same province.
Probably the largest deposits of vanadium yet discovered in the United States are in southwestern Colorado in San Miguel County. These deposits were visited by Ransome and Spencer in 1899 and their description, together with notes on the chemical analyses and composition of roscoelite by Hillebrand, was published in 1900. Fleck and French have also described the deposits. Fleck and Haldane later published additional descriptions, with notes on mining operations. Hess, in 1912, published an excellent description of these deposits with notes on the possible origin, etc.
According to Cross and Purington, the country rock is composed of Jurassic and Triassic sediments, divisible into three formations, the Dolores below, La Plata above and McElmo above La Plata. The latter is composed of two heavy beds of light-colored sandstone, separated by a thin bed of limestone. The vanadium-bearing rock is the lower sandstone. It is a light to dull green, and fine-grained. Occasionally splotches of carnotite are found in the cracks and fissures, but the uranium content is too small to be worth saving.
According to Hillebrand, the green vanadium mineral to which the sandstone owes its color is not a chlorite, but is closely related to the mica, roscoelite. The ore mined has an average content of 1¹⁄₂ per cent. V2O5. These low-grade roscoelite deposits can be mined at a profit, because they are large and easily worked.
Undoubtedly these deposits have been feeling the effects of the rather large production of the last few years, and the average grade of the ore is now probably at least half of a per cent. lower in V2O5 than it was a few years ago. There is still considerable ore untouched that will average 1 per cent., or a little less. The British government for several years, according to reports, has been interested in obtaining control of vanadium deposits.
The Primos Chemical Co., with works at Newmire, Colorado, and Primos, Pennsylvania, is mining these deposits, and in 1917 made this production:
Treated 60,907,000 pounds of ore; from this was produced 496,731 pounds of vanadium in the form of iron vanadate running about 34 per cent. metallic vanadium. From this was produced 417,770 pounds of contained vanadium in the form of regular 40 per cent. ferrovanadium. In 1918, up to and including July, this company mined 17,449,000 pounds of ore, from which was produced 149,343 pounds of contained vanadium in the form of vanadate of iron and 133,666 pounds of contained vanadium made in the form of 40 per cent. ferrovanadium.
In 1919 the Primos Chemical Co., was absorbed by the newly organized Vanadium Products Corporation.
Vanadium ore has been discovered in Huerfano County, Colorado, near the Sangre de Cristo Range. The vein is said to be well defined and 1 to 4 feet in width. A number of assays show 2 to 7 per cent. V2O5 content, and others 2 to 4 per cent. copper. The ore is heavy, black and banded; it contains small quantities of uranium oxide, but should be classed as a vanadium, rather than a uranium mineral. There has been no commercial production up to date.
In Eagle County, 7 miles southeast of the town of Eagle, a silver ore has been found that carries vanadium. This was located mostly in the Lady Bell mine. The ore, a dark-greenish sandstone similar in appearance to the darker types of roscoelite ore found in San Miguel County, assayed from 25 to 1,000 ounces of silver to the ton. The mine has been largely worked out for silver, the vanadium being lost during the smelting process. There is still, however, an appreciable amount of vanadium ore left, as the low-grade silver ore was not mined or treated.
A considerable amount of vanadium is obtained as a by-product from the treatment of carnotite (uranium and radium) ore. It is difficult to say just what the yield from this ore is, but it is probable that it averages about 200,000 pounds of vanadic oxide per annum. This is produced by five or six operating radium companies. These deposits are found in southwestern Colorado, around the Paradox Valley, and in southeastern Utah, extending as far as the San Rafael Swell, southwest of Green River, Utah.
There is considerable ore running one-half to 1 per cent. uranium oxide which carries from 4 to 10 per cent. vanadic oxide. In the past this ore has not been mined, because the extraction of radium from it would not pay. With a strong demand and a high price for vanadium, at least the higher grades of this ore could be mined at a profit. There is considerable of such ore at certain localities north of the Paradox Valley; unfortunately, these deposits are somewhat scattered and some would involve not only long wagon hauls, but also transportation by burro to wagon roads. Only the higher-grade ore could be handled in this way at a profit, and the difficulty is to get enough to justify building a treatment plant.
The writer has been told that there are deposits of this same type of ore at Temple Mountain, 40 miles south of Green River, Utah.
A small vanadinite deposit, containing traces of wulfenite, has been found near Klinefelter Station, on the main line of the Santa Fe Railroad, near the eastern border of San Bernardino County, California. The ore is largely calcite and is low grade, averaging probably from 1 to 2 per cent. vanadic oxide.
A deposit of vanadinite in Sierra County, New Mexico, on the Atchison, Topeka & Santa Fe Railroad, was mined for a short period in 1912 and 1913. Besides vanadium, the veins contain galenite, copper carbonates, barite, fluorite and other minerals. The ore was treated at a mill close to the mine, but the whole undertaking was unsuccessful, probably because the ore was so low grade, and because of metallurgical difficulties. There are a number of other deposits of vanadinite in New Mexico, but none of them have been commercially developed in any way.
Vanadinite is found in a considerable number of places in Arizona, frequently associated with wulfenite, or lead molybdate. Indeed, one of the difficulties of producing both vanadium and molybdenum from vanadinite and wulfenite is the fact that the two minerals are frequently so closely associated that, because of the slight difference in specific gravity, it is not easy to separate them by mechanical methods. At the Mammoth mine, in Arizona, the upper levels are richer in vanadinite than in wulfenite, but at the lower levels, the reverse is true. Undoubtedly a considerable amount of vanadinite could be produced from this mine and others in the vicinity, but it is doubtful whether it could be done at a profit, even at a high price for vanadium.
The United States Vanadium Co. has a mine 4 miles from Ray Junction, Arizona, and at the mine a small mill to concentrate the ore, which is low grade, and produces vanadium from the concentrates. The amount of ore that can be obtained from this mine is somewhat doubtful. This is the trouble with vanadinite as a whole; it exists over a wide territory, but the deposits are all low grade and apparently are not extensive in any one locality.
One of the most promising deposits, as regards increased production of vanadium, is at the Shattuck mine, Bisbee, Arizona, where a large vug, or cavity, is lined with a vanadium mineral, probably cuprodescloizite. The ore carries about 8 to 10 per cent. vanadic oxide, in addition to copper and lead. This seems to be one of the best opportunities for an increased production of vanadium in this country. The Golden, Colo., station of the United States Bureau of Mines made a metallurgical study of the treatment of this ore.
Plate V.—Geographical distribution of the vanadium deposits of the world.
The distribution of the vanadium deposits of the world is shown in [Plate V].