Design, fabricate, and test a machine capable of operating in coal seams 48-inches and thicker that can reduce the time, expense, and injury potential inherent in extending and retracting mine-wide section belt conveyors, while eliminating the need to use additional machinery or equipment in accomplishing such moves. The Problem Many underground coal mines use a … Read more
This report presents the results of research aimed at evaluating and preventing the leaching action that may result from the disposal of waste ferrous slags into landfills where they can be subjected to acid precipitation. Waste slag constitutes a large potential source of chromium contamination of ground waters, particularly under the enhanced leaching action of … Read more
To help assure an adequate supply of raw materials to meet national economic and strategic needs, the Bureau of Mines undertook research to devise technology to efficiently and economically recover titanium from low-grade domestic deposits. The objective of this research was to devise a means for producing chlorination-grade feedstock from low-grade ilmenlte rock concentrate made … Read more
The fact that chloride oxidates can solubilize base metals from sulfide concentrates has been known since the 1880’s. The work of Hoepfner in 1902 was particularly accurate for its time with regard to the chemistry of chloride solutions. Recent work has dealt with the understanding of chloride extraction thermodynamics by modelling the behavior of metal … Read more
This is of special interest in hydrometallurgical processing since it provides an upgraded sulfide and rejects iron to solution. Also, the conversion of chalcopyrite is an important process in secondary mineralization during supergene enrichment, and secondary mineralization may occur during long cycles of dump leaching. In deep solution mining, secondary reactions undoubtedly will assume an … Read more
Metal complexed cyanides in wastewaters form as a result of interactions of free cyanide with metals present in the wastewater and exhibit varying degrees of stability, toxicity, and treatability. Thiocyanate, a pollutant commonly found in cyanide bearing wastewaters, is formed through the interaction of free cyanide with sulfur containing species (i.e. pyrrhotite) both present in … Read more
Improper size distribution of the grinding media in a multicompartment mill can be a source of many operation problems encountered. Inefficient use of the power expended for grinding, and an undesirable product size distribution are two frequent resultants. The objective then is to provide a method which would be practical to use and accurate enough … Read more
In the clay-HCl miniplant, leaching sized, calcined kaolin with HCl was carried out in 50-gal, glass-lined continuous, stirred tank reactors (CSTR’s). Originally four reactors arranged in a cascade configuration were used, but experience showed that acceptable alumina extraction was obtained with three reactors. The fourth reactor was kept on a standby basis. The reactors were … Read more
There has been considerable interest in developing methods to economically produce cell-grade alumina from nonbauxitic materials. In the United States, this interest stems principally from a lack of sufficient bauxite deposits suitable for Bayer processing. In 1973, the Bureau of Mines initiated a program to study the options available for recovering alumina from domestic resources. … Read more
The AMAX sulfuric acid leaching process involves countercurrent digestion of nickeliferous laterite ore at high pressure and at atmospheric conditions. After solid/liquid separation, the nickel and cobalt values are precipitated by hydrogen-sulfide and refined into nickel and cobalt metal. Research at AMAX began in the early 1970’s at AMAX’s Extractive Research and Development Laboratory in … Read more