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By C. B. Daellenbach

The influence of reduction roasting and thermal shock on the grindability of a refractory low-grade Michigan iron ore was examined in bench scale tests. The quantitative effects of the various treatments were evaluated at three sieve levels: 48, 100, and 400 mesh, using ball mill grindability and work index parameters as response indicators. Data from the testing program were analyzed statistically as a means of isolating the effects of cooling rate, roasting temperature, and ore chemical condition. All three variables were found to have an important influence on the grindability of the treated ore; ore chemical condition and roasting temperature had the most pronounced effects.

Jan 1, 1970

By Richard A. Brown

The direct precipitation of uranium with hydrogen peroxide has been known since 1877. Commercial use of the process began in the 1960's. During 1967 the Bureau of Mines assisted the Climax Uranium Co., Grand Junction, Colorado in the development of a uranyl peroxide precipitation process to control a molybdenum impurity problem (1). Atlas Minerals, Moab, Utah has used hydrogen peroxide to control vanadium and sodium levels in their uranium concentrates since 1969 (2). Recently, the use of hydrogen peroxide by the uranium industry has grown, particularly since the increased demand for uranium has led to the processing of low grade ores. Impurities present in low grade ores can be concentrated with the uranium during milling and will substantially complicate the refining of uranium yellowcake concentrates. Consequently, commercial nuclear fuel processors have imposed stringent specifications and penalties to control these impurities. The ability to produce a pure uranium yellowcake can eliminate penalty or reprocessing costs. Hydrogen peroxide precipitation of uranium is specific and quantitative, producing a very high purity product.

Jan 1, 1980

By Richard J. Frechette

Final reclamation of mine tailings impoundments typically involves addressing the broad issues of surface stabilization and water management. Surface stabilization includes immobilizing the tailings particles and providing long-term protection of the containment facility. Water management typically includes provisions for handling both the external water (rainfall and runoff) and the internal water (pore fluids). Wet tailings disposal facilities, and sites with limited access and steep topography, present challenges to implementing effective surface stabilization and water management plans. This paper presents a generalized discussion of the approach to tailings impoundment reclamation based on project experience.

Jan 1, 1995

By Oleg N. Tikhonov

The paper deals with computerized analytical design of separational mineral processing flowsheets for flotation, gravity separation, magnetic separation, etc. (without comminution). Initial data include fractional composition of the feed ore, separational characteristics of the unit operations, and optimality criterion. Computer-calculated results display optimal flowsheet configuration and optimal parameters of unit operations like tonnage, residence time, etc., which allows the choice of equipment. An example of apatite flotation flowsheet design is given. This analytical approach may be used for automatic process control purposes as well.

Jan 1, 1989

By W. J. Pennstrom, J. R. Arnold

Gold Fields installed what was the mining industry's first commercial gold electrowinning/replate circuit at Ortiz in 1981. Its highly successful operation since that time provided the design basis for a similar circuit at Mesquite, which was started in early 1986. These circuits produce plated gold foil suitable for direct shipment to a refinery or melting directly into bars. Detailed descriptions of the electro- winning and replate circuits are given and advantages and disadvantages are discussed.

Jan 1, 1988

By H. J. Sohn, S. G. Doo

A systematic study was carried out to investigate the reduction reaction mechanism of oxygen on pyrite surface using electrochemical techniques. The polarization curves showed two distinct regions, the Tafel region for superoxide formation and limiting current region for diffusion of dissolved oxygen to form hydrogen peroxide. These results were confirmed with a-c impedance measurements.

Jan 1, 1990

By K. J. Stanaway

Environmental pressures on waste disposal are forcing pigment producers to use feedstocks with higher Ti02 content and lower levels of trace elements. Despite this, 50% of the world's Ti02 comes from ilmenite concentrates with only 37% to 54% Ti02. An industry growth rate of 25% in the next 10 years, combined with trends to diminishing resources and lower mining grades for rutile (95% P02) and leucoxenized ilmenite (55% to 90% P02), means that unless new discoveries are made soon, the industry will become even more reliant on ilmenite.

Jan 1, 1995

By R. J. Snoby, P. Grotjohann

In processing heavy-mineral sands, the low feed concen¬tration and respective high value of the desired minerals require high-capacity production and sharp classification/ separation techniques to reduce the specific production costs. This paper describes the new allfux® separator, which can economically accomplish these criteria. The separator is a two-stage process that combines rising current and fluidized-bed technology. This allows for the treatment of ex¬tremely high mass flows in a single unit. This paper reports on test work performed on coal, iron ore and heavy minerals.

Jan 1, 2000

By G. R. Brunskill

The molybdenite flotation plant at the Magma Copper Co. San Manuel concentrator has been in operation since 1956. In January of 1980, the plant was converted from a hydrogen peroxide-ferrocyanide process to the current sodium cyanide-sodium hydro- sulfide process. This paper is an operational review of Magma Copper Co.'s molybdenite recovery circuit, column cell flotation experience, and use of on-stream X-ray fluorescence analysis.

Jan 1, 1987

By K. K. Bhattacharyya, S. Bhattacharya, S. Dey

Coal batch flotation tests were conducted both with and without collector and with one- and two-stage additions of frother. The recovery of combustibles and the flotation rate constant were found to be higher with two-stage frother addition, both with and without collector.

Jan 1, 1998

By M. C. Fuerstenau

Collophane, cryptocrystalline fluorapatite, is examined as a substrate for plant water and wastewater remediation. The attenuation of Fe3+, Cr3+, Fe2+, Cd2+, Hg2+ and Pb2+ is presented as a function of metal ion concentration, amount of collophane, initial pH and conditioning time. TCLP results for Pb2+ contaminated collophane are presented. Mechanisms of adsorption for divalent and trivalent species are suggested. Key words: Collophane, Wastewater remediation, Heavy metal removal

Jan 1, 2003

By T. Altman

Using theory of network planning together with graph theory, an algorithm is presented that creates canonical diagrams for mine ventilation networks (M VN). The data generated by the algorithm is used in the construction and plotting phases of a program that automatically plots the canonical diagrams, which can then be used for further studies of a given MVN.

Jan 1, 1988

By F. N. Kissell, N. I. Jayaraman

Dust scrubbers on continuous miners are steadily gaining in popularity. Recent US Bureau of Mines research on scrubbers is reviewed, with emphasis on development of a new type of water-powered scrubber that can be retrofitted to existing miners; comparison of scrubber effectiveness with blowing and exhaust line ventilation; and improving the quartz dust collection of flooded-bed panels.

Jan 1, 1991

By G. G. O. O. Uwadiale

Starting from a crude ore assaying 45.6% Fe, a fine-grained oolitic iron ore was concentrated by the oil agglomeration technique to 90% Fe recovery and 65% Fe assay. The ore required grinding to minus 5 µm to effect adequate liberation, and the technique yielded optimum results at pH 9. The roles of pH, collector, and bridging liquid concentrations on selectivity and yield of iron minerals in the concentrates are discussed.

Jan 1, 1991

By S. D. Thompson, J. C. Dzurino

This investigation mainly focused on designing a bunker system for a large underground coal mine. The primary purpose of this bunker system was to keep high- and low-sulfur coal segregated on the underground belt system. These bunkers were also required for protecting the mine faces from out by belt delays. Methodologies used in developing this plan are briefly discussed. The final design and the procedures formulated for implementing it are also presented.

Jan 1, 1987

By Frank Matter

Production of ultrafine powders of industrial minerals has been a problem in the past. In recent years new wet and dry grinding stirred ball mill systems have emerged which have been commercialized Two such systems are the TRZK mill with double step air classifier for dry grinding and the NRZK mill for wet grinding The primary features of these mills are feed entering from top and the product along with the grinding media leaving from the bottom, and a media separation and recycle system A detailed description of the NRZK mill for grinding coal is presented

Jan 1, 1983

By Gabriel E. Zárate, Juan C. Guzmán

In Chile there are significant amounts of gold in flotation tailings that could be recovered, being heap leaching the most promising alternative. In order to determine the feasibility of treating these tailings by this method, a detailed study is carried out using 4 representative samples. After defining the best conditions an economic evaluation is done for a plant treating 200 tpd, sensibilizing with respect to parameters such us gold price, tailing grade and capital costs. The results show that it is technically feasible treat these gold tailings by heap leaching with gold extractions over 70 %. It is also economically feasible for gold grades higher than 0.5 g/t and gold prices over 350 US/oz.

Jan 1, 1987

By J. W. Oberholzer

Problems with gravimetric sampling have led to the establishing of a computer linked tyndallometer dust measuring system. Preliminary tests conducted with the system indicate that the system can be used to do correlative exercises between mining activities and dust levels. The system also allows occurrence characteristics of dust levels to be determined. Use of this equipment will enable dust allaying methods to be tailored to the specific underground situation.

Jan 1, 1987

By J. A. Herbst, L. B. Hales, R. A. Ynchausti

Industrial application, theoretical discussion and technical research programs continue to stimulate acceptance of column flotation. Numerous authors have published model, parameter and application studies discussing advantages and problems which are associated with this minerals processing technique. This paper dispells the myth of the self-controlling column while focusing on the problems and opportunities which are inherent in the computer control of a column flotation cell.

Jan 1, 1988

By D. Butler

Subsurface density changes can be detected by very precise surface gravity measurements. A feasibility study, combined with field experience using modern instruments, will indicate the probability of success. In addition to projected anomaly parameters, surface conditions that effect the survey precision must be evaluated. Examples with excavated zones at 9 m (30 ft) of depth and [+] 22 microgal error are compared to the same model at 30 m (98 ft) of depth. The figures illustrate anomaly detectability. The survey error is a function of surface topography and lateral density variation in the very near surface.

Jan 1, 1990