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.