67 resultados para sulphide ore
Resumo:
The largest known deposits of tungsten ores occur in the continuation of the Indo-Malayan Mountains, which extends through Burma, Malaya, China, Japan, and Chosen. Production of tungsten concentrates was started in 1910 in Burma, and in 1911 this country was the world's largest producer. China produced but little until 1916, but has since supplied over fifty per cent of the world's requirements.
Resumo:
Potential gold mines lie high among the rugged peaks of the Tobacco Root Mountains of southwestern Montana. This is a region where little geologic work has been done, though extensive mine operations have been carried on, and valuable ore has been shipped.
Resumo:
The United States, although the leading consumer of chromite, depends almost entirely on imports for its supply. Domestic production of chromite is limited, because high-grade imported ore is plentiful and inexpensive in normal times. There are several large deposits of chromite in the United States, representing millions of tons of low grade ore. These deposits form a strategic reserve that must be used in time of national emergency.
Resumo:
The possible benefits of oxygen enriched atmosphere roasting have been known to metallurgists for many years, but only since the development of equipment and processes to produce cheap oxygen in very large amounts has much serious consideration been given this matter.
Resumo:
Imports of manganese ore probably supply a major proportion of the needs of the United States. Domestic production is reported to be higher than pre-war levels, but does not equal that of the peak production year of 1943. In 1946, the Anaconda Copper Mining Company accounted for 90 percent of the total shipments of manganese nodules, and this company is the largest producer of domestic metallurgical ore in the United States.
Resumo:
Chromite is the most important ore used for the production of chromium and chromium alloys. At present, the domestic production is insignificant as compared with the amount of chromite consumed in the United States.
Resumo:
For many years the Elliston District, of Powell County has been a minor producer of gold, lead, zinc, and silver. Although never among the largest producing districts of the state, it has with the exception of the war years supplied a notable tonnage of ore to the neighboring mills ever since the first placer and lode claims were located there during the late eighteen hundreds.