Many mineral samples are sent to Government agencies with the request that they be assayed or chemically analyzed. It should be emphasized that there are no Federal agencies, except for the U.S. Mints, where assays and quantitative analyses are made for the public. Many of the States maintain a Bureau of Mines, a Geological Survey, … Read more
The principle oxide minerals of molybdenum are wulfenite (PbMoO4), ferrimolybdite (Fe2(MoO4)3·nH2O), powellite (CaMoO4), and ilsemannite (Mo3O4). Wulfenite is found in Arizona, New Mexico, Nevada, Utah, California, and Montana. It is also found in the states of Sonora and Chihuahua, Mexico. Prior to 1915 wulfenite ores were the primary source of molybdenum. All leaching experiments were … Read more
The Vor-Siv Dewatering and Classifying Unit was developed by the Polish Coal Industry because of a need for a unit that would dewater and classify high volumes of solids in water slurry. To be practical, the unit needed to be relatively small in size, simple in design, involve low operating costs, and be able to … Read more
The height, structure, rapid rate of growth, and anticipated leaching suggested the possibility of dump failure. In order to evaluate this possibility, an outside consulting firm was retained in 1966 to investigate the stability of the growing dumps. Their investigation indicated that, other than superficial movement, the waste dumps would be stable under static loading, … Read more
The closure of zinc plants has reduced smelting capacity in the United States from 1,300,000 tons in 1969 to approximately 700,000 tons in 1974. At the same time, U.S. consumption of zinc has increased, as shown in figure 1. As a result, the United States must import over 50 pct of its zinc supply from … Read more
Manufacture and mixing of flotation reagents at the mill site provides an economic and convenient method of maintaining a continuous and fresh supply of reagents for concentrator operations. Kennecott Copper Corporation has designed and built a Reagent Mixing Facility which incorporates new ideas in construction and fail-safe operation at its Nevada Mines Division concentrator. Reagents … Read more
Mill liner design is an important factor in grinding. Testing and selection of the optimum liner profile for a given set of mill operating conditions can improve mill capacity, liner life, and liner wear rate. In testing four mill liner profiles for 13′ x 12′ overflow ball mills. Climax found that an improved design increased … Read more
There are two principal methods in use for processing the 8 million cars that are scrapped annually in the United States. About one-half of the cars are processed by shredding in which automobiles minus radiators, batteries, engines, gas tanks, and seats are ripped into fist-sized chunks and then magnetically separated to produce a ferrous scrap … Read more
The minntac complex is a facility for production of iron ore pellets located on the mesabi range at mountain iron, minnesota. It consists basically of a mine, crushing plant, concentrator, and a pelletizer producing twelve and one-half million tons of pellets annually. This paper deals with some of the aspects of the grinding circuits; but … Read more
Experimentation with chalcopyrite concentrate in dilute hydrochloric acid, under reflux conditions (in Pyrex flasks) and with an inert purge gas, revealed substantial amounts of H2S production and iron solubilization, with negligible copper solubilization, after 2½-4 days. Under comparable condition the extent of reaction with dilute sulfuric, acetic and phosphoric acids was markedly less. Pertinent Chemistry … Read more