Investigations were conducted by the U.S. Bureau of Mines to develop flowsheets for the recovery of tungsten and gold from four Alaskan scheelite-bearing ores. Basic gravity concentration and cyanide leach tests were performed on all samples. About 46 pct of the tungsten and 30 pct of the gold from one sample were recovered in a … Read more
We treated mixed and contaminated superalloy scrap by pyrometallurgical and hydrometallurgical methods to separate and recover metal values. Best results were obtained by leaching Zn-treated or atomized scrap with HCl-O2 at 95° C and 50 psig O2. This resulted in dissolving approximately 98% of the Al, Co, Cr, Cu, Fe, Mn, Ni, and Zn while … Read more
We determined the effect of common sulfide minerals on the corrosion rates of various types of ferrous alloy grinding media. Data obtained from this study will aid in determining the contribution of any electrochemical reactions between sulfide minerals and grinding media to the total grinding media consumption. Common sulfide minerals used in this study were … Read more
We investigated the role of imported natural flake graphites in dolomite-carbon refractories used in steelmaking processes and evaluated carbon fibers as a potential substitute. Varying quantities (1.5-30 pct) of natural flake graphite and carbon fibers were added to test samples. The effect of the additions on modulus of rupture (75°-2,750° F), deformation under load (2,750° … Read more
We performed batch equilibrium contact experiments to examine the ability of activated coconut-shell carbon to adsorb various metal cyanide complexes. Tests were also conducted to determine the effect these cyanide complex impurities might have on the adsorption of gold by the activated carbon. Metal cyanide species included in the investigation were antimony, arsenic, cadmium, calcium, … Read more
We have developed an improved method for determining dissolved helium in water in the concentration range of 4.0 x 10 -8 to 270 x 10 -8 cm³ He (STP)/cm³ H2O. The method is a modification of a previously reported method that was developed for analyzing surface and subsurface waters in geochemical survey work. Water samples … Read more
This report presents a study of three typical tailings samples as potential cemented backfill in underground mines. The testing series was unique in that the pulp densities of the samples were all above 75 pct solids. Test results included dry density; slump; percent settling after 28 days of curing; tensile strength after 28, 120, and … Read more
Objective Reduce the number of conveyor-related accidents in the mining industry by providing recommendations for effective operation of conveyor belt cleaning systems. The Problem Troughed belt conveyors provide effective and efficient materials transport and their use has increased throughout the mining industry. Carryback, the spillage that accumulates under the belt, is a problem even with … Read more
Abstract The U.S. Bureau of Mines has patented and transferred to industry an abrasive-enhanced water-jet rock drill. This drill incorporates three novel components: a collimator, jet deflectors for cutting clearance, and an unpressurized swivel, which rotates at 1,000 rpm while passing 20 gpm of an abrasive slurry flowing at 1,000 ft/s. Drilling occurs through the … Read more
Objective Utilize innovative processing technology to prepare high-purity, ultrafine advanced ceramic powders with little or no contamination occurring during the milling proccss. Advanced ceramic materials made from these powders could substitute for high-temperature alloys containing critical materials such as chromium, cobalt, and nickel. Approach Modify and evaluate the Bureau’s turbomill, developed earlier to grind a … Read more