To insure the continuing viability of the domestic minerals and materials economy and the maintenance of an adequate minerals base, the U.S. Department of the Interior, Bureau of Mines, has been investigating the development of methods for improving gold and silver recovery from low-grade resources. Discoveries during the past decade of numerous low-grade, gold-silver deposits … Read more
In recent years interest in hydrometallurgy, particularly in the case of in-situ leaching and solution mining has remained at a high level. There are several studies published on the development of scale-up principles. D’Andrea and Runke described research on in-situ copper leaching at the Emerald Isle Mine whose dominant copper mineral is chrysocolla. The program … Read more
It has long been recognized that the 9 million tons of lead ore mined annually from Missouri’s Lead Belt (83 pct of the U.S. domestic production) contain significant amounts of nickel and cobalt. Yet, neither of these important commodities is being recovered by the current processing depicted in figure 1. The pyrometallurgical treatment of primary … Read more
The analysis of particle size distributions has become increasingly important in industrial processes. Particle size is recognized to be fundamental to the control of operations as diverse as grinding, crystallization, emulsification, agglomeration, and more. Particle size determination has traditionally been relegated to the laboratory, and is performed by slow, labor-intensive methods such as sieving, sedimentation … Read more
In the commercial dump leaching of copper, two methods have been generally accepted as a means for recovering copper from pregnant leach liquors. The oldest and most widely used technique is copper cementation with scrap iron. The newer technique involves solvent extraction and electrowinning. As part of a program to assure adequate domestic supplies of … Read more
The Bureau of Mines has funded an extensive research program to develop improved scrubbers for coal mine applications. This work shows that scrubbers can offer a highly effective technique for dust control during many mining operations. In the most recent applications, these scrubbers are usually mounted on or in the mining machine, and minimum scrubber … Read more
The kinetics of solvent extraction with hydroxyoximes are complex, involving mass transfer with chemical reaction in a heterogeneous system. One is therefore faced with a wide spectrum of possible behaviour within certain well defined boundary conditions. The extraction rate could be diffusion-controlled under all conditions and would thus depend on the interfacial area, and concentration … Read more
Shell liners wear very fast in very large diameter autogenous and semi-autogenous mills. In addition to shell liner wear, the ends of the mill are susceptible to very high rates of wear, generally confined to fairly narrow bands. Due to the sheer size of modern mills, extensive downtime is required to replace shell liners or … Read more
Determine what diameter piping is necessary to obtain sufficient water flow to spray nozzles used for dust suppression. A simplified, diagrammatic method of calculating the flow of water through a proposed system consisting of a supply line and two banks of spray nozzles is outlined. How it Works The pressure versus flowrate of the supply at … Read more
Among the significant technological accomplishments of the third quarter of the 20th century was the wide application of vacuum-to-metal melting. Many of the more common metals, as well as superior alloys of steel, have benefited from vacuum degassing, and the production of reactive and refractory metals leans heavily on vacuum-melting techniques. Fabrication and other forming … Read more