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By H. B. Oblad

The WEMCO® SmartCell™ flotation machine is a continuously-stirred tank reactor in which solids are suspended in water and are contacted with air. The reaction is particle flotation resulting in the separation of valuable material from gangue. The effects of several operating variables on the flows of water and air and on motor power were measured. A miniature magnetic flowmeter was installed in the draft tube that allowed measurement of the water flows into the rotor. This work has led to a better understanding of machine function which will lead to improved performance and better operation. General equations for optimization, design, and scale-up were inferred.

Jan 1, 2002

By O. K. Kuznetzov, L. A. Otrozhdenova, N. D. Malinovskaya, I. I. Maksimov, N. D. Khodov

While processing zinc cakes with application of Weltz-technology silver remains unrecovered and goes into clinker. In order to prevent it the elaboration of effective silver recovery methods from zinc cakes before their weltzing becomes necessary. A combined method of zinc cakes treatment with leaching and flotation in a closed water circuit has been worked out. The technological scheme envisages the use of sulphgydril collectors in combination and comprises a series of consecutive operations: leaching, filtration, precipitation(cementing) and flotation. Total silver recovery is approximately 94%. The technology elaborated has been realized in a project by which the construction of a new shop is under way now.

Jan 1, 1995

By R. V. Ramani

This paper is based on the thesis that the demand for computer-oriented mining engineers will continue to sharply increase in coming years. It presents the philosophy behind the development of a mine systems engineering program at The Pennsylvania State University. The paper discusses the current status of mining engineering education and the problems encountered in integrating extensive computer background and education into a traditional mining engineering program. The paper analyzes the interrelated roles of research, graduate studies, and continuing education in developing a comprehensive program of study. It is hoped that this program philosophy will be useful to other institutions which are contemplating new programs and courses in emerging technologies.

Jan 1, 1982

By L. L. Oriard

The author describes three case histories of fracture-control blasting demonstrations. This is a technique in which the walls of blast holes are scribed or notched in order to enhance the development of blast_induced fractures, and to control their direction. One demonstration was that of a tunneling application in a rock that was generally competent but strongly foliated, hence strongly anisotropic. P second test was conducted for perimeter blasting of a structural excavation in a massively jointed limestone. A third field test was conducted for tunneling through an old concrete structure. Increased applications are envisioned with new tool modifications being developed at the University of Maryland.

Jan 1, 1981

By K. N. (Mani) Subramanian

A 2.5 meter diameter column has been successfully used in a 100 tph flotation plant at the Harbour Lights Mine in Leonora, Western Australia, to produce a final gold bearing sulfide concentrate from the ore in a single stage. This pioneering application of column flotation cells to rougher stage was pilot tested using a 11 cm column, which demonstrated column's capability in rougher, scavenger and cleaner flotation stages. A hybrid circuit involving columns and mechanically agitated flotation cell s was adopted for the commercial installation. This paper describes pilot plant results, design of the plant flotation circuit, and early results of commercial operation.

Jan 1, 1988

By C. A. Wiggins

The new Niagara Falls Intake Tunnel, mined in the highly fractured Lockport Dolomite, encountered prolific inflows of water contained in rock seams directly linked to the Niagara River. These inflows were pressurized and, more significantly, contained high concentrations of dissolved H2S gas. The contractors attempts to control the water/gas inflows included cement and chemical grouting from inside the tunnel. Ultimately, improving the rate of air exchange in the tunnel by increasing the fan capacity, in conjunction with a pattern down-hole pre-grouting program along the tunnel alignment allowed the contractor to control the concentration of H2S gas and complete the tunnel.

Jan 1, 1997

By N. N. Clark, C. M. Atkinson

Pachuca tanks are used widely in the mineral industry for leaching and mixing operations. An analysis has been presented previously to predict circulation of homogenous slurry in Pachuca tanks with full height draft tubes. However, settling of solids causes deviation from the homogenous case. Circulation of settling slurry in a Pachuca tank is modeled and shown to be a function of settling velocity, solids fraction, solid and liquid density, air flew rate, and tank dimensions. The pressure balance is shown to be very sensitive to these parameters, especially at low slurry velocities. Equations for predicting the air requirements in Pachuca tanks containing settling solids are presented.

Jan 1, 1988

By J. B. Gwiazda

In designing mine workings and adequate roof supports, it is indispensable to determine properties of the strata surrounding the workings. The proper selection of roof supports is based, before everything else, on a thorough knowledge of the roof rock strength, especially tensile strength. This parameter is a vital factor in the delamination of roof rocks and eventual cave-in. It is also important to know the properties of the floor on which the roof supports are set. While driving galleries, it is essential to know beforehand the strength of rocks that will be encountered in the near future during the work. The devices described will help to obtain this information.

Jan 1, 1987

By T. A. Toney, L. R. Fish, P. J. Bethell

With new lightweight designs, spirals have become standard equipment in coal preparation plants worldwide. To their credit, spirals typically show very low coal losses to the refuse stream under most operating conditions. However, spirals do tend to separate at cut points in excess of 1.80 S.G. Attempts to obtain lower cut points have typically resulted in coal losses to middlings. Middlings retreatment with secondary spirals is therefore becoming common place. Other forms of retreatment with water-only cyclones, hydrosizers and recirculation have been attempted with some success. This paper reports on a novel (patent applied for) approach to retreating spiral middlings in a heavymedia cyclone circuit.

Jan 1, 2000

By R. W. Smith, R. K. Mehta, X. P. Zheng, A. M. Raichur, M. Misra

Experimentation was per formed on the flotation of apatite and dolomite separately using anionic collectors in the presence of Mycobacterium phlei. Also, the flotation of mixtures of dolomite and apatite in the presence of anionic collectors and in the absence and presence of the bacterium were studied. It was found that M.phlei functions as a depressant for both minerals. However, it functions as a better depressant for dolomite than for apatite. Experimentation was extended to two different Florida dolomitic phosphate rocks. In this investigation a concentrate grade of less than 1.0% MgO was achieved with a 75% P2O5 recovery.

Jan 1, 1999

By S. G. Malghan, D. Santhiya, S. Subramanian, K. A. Natarajan

The adsorption of poly(vinyl alcohol) (PVA) of molecular weight 25,000 onto alumina was studied as a function of pH. The adsorption isotherms were also determined. The adsorption density increases with increasing pH, while the isotherms are rounded and of the low affinity type. Electrokinetic studies indicate that the electrophoretic mobilities are reduced in magnitude in proportion to the PVA concentration, without any shift in isoelectric-point (iep). This resembles the influence of an indifferent electrolyte. The calculated values of the free energy of adsorption between alumina and PVA are suggestive of hydrogen bonding. FTIR spectro-scopic data provide additional evidence in support of hydrogen bonding.

Jan 1, 2000

By T. Gouri Charan, G. V. Rao

A spherical agglomeration process for the separation of scheelite fines of less than 30 µm in very low concentration of 0.04% WO3 in a binary mixture with quartz fines of less than 30 pm has been described. A concentrate containing 14% WO, with more than 90% recoveries could be achieved by means of anionic sodium sulfo succinate collector at pH 3.5 and also with commonly used anionic sodium oleate at pH 10.5 as per the conceptual flowsheet suggested. Such a process is envisaged as commercial potential for the recovery of fine-grained scheelite present in the tailings of gold plants as found in India.

Jan 1, 1991

By J. Paraszczak

Water-powered jackleg rock drills, introduced recently in South African mines, are reported to be more efficient, faster and more comfortable to operate than conventional pneumatic drills. Comparative testing of these drill types was performed in Quebec. Based on the test results and on time studies performed in the mines, water-powered drilling was reviewed. The review considered the drilling rates achieved, the infrastructure needed, side effects and health and safety considerations. This study shows that the application of water-powered drills may, under specific conditions, help increase the footage drilled and may improve the working environment. Examples of such applications are presented in the conclusions.

Jan 1, 1997

By R. A. Metz, Ted H. Eyde, Dan T. Eyde

Industrial minerals deposits present sampling and grade control problems not normally encountered in metal mining operations. No longer are industrial minerals simply crude ground mineral products but are in fact high purity chemical raw materials. Operators of industrial minerals mines and processing plants now must meet increasingly stringent specifications established by the consumer of the final products. Meeting these stringent specifications requires not only sophisticated processing techniques but equally important careful sampling and grade or quality control at the mine. A well-trained geological staff can assure an adequate supply of uniformily high quality feed to the processing plant. In the final analysis this results in significantly higher operating profits.

Jan 1, 1992

By Jeffrey D. Swanson, Martin L. Smith

Smelterville Flats in Idaho's Silver Valley has been designated as a Superfund site due to metals contamination resulting from the use of the South Fork of the Coeur d'Alene river as a tailings impoundment earlier in this century. Tailings average in excess of 4% lead and zinc. Selective mining of highly contaminated zones is being studied as one of several possible remediation strategies. The first step towards remediation is the examination of the stratigraphic, geochemical and spatial characteristics of the site. These characteristics are related to appropriate sampling protocols and exploratory sample grid design. Special problems involved in the geostatistical analysis of tailings are emphasized.

Jan 1, 1992

By T. V. Vasudevan, J. Blaakmeer

Adsorption experiments were conducted at two different solid loadings to investigate the mechanism of oleate adsorption on apatite. Adsorption density at pH 10 was found to be dependent on solids loading in an oleate concentration region where surface precipitation could occur. Analysis of adsorption isotherms indicated three distinct regions of adsorption. In region I (below the region of calcium oleate precipitation), molecular adsorption was observed. Simultaneous molecular adsorption and surface precipitation occurred in region 11, while surface precipitation was predominant in region I11 along with some bulk precipitation. Correlation between flotation of apatite with sodium oleate and the mode of oleate interaction with the surface is established.

Jan 1, 1988

By S. G. Malghan, V. K. Pujari

Detailed characterization of all the powder constituents during powder processing is necessary for the reproducible manufacture of ceramic components that will perform reliably in intended applications. In this paper, selected physical and surface chemical techniques for characterization of silicon nitride powder are evaluated. The characterization data are discussed in the context of how these data, through their influence on powder processing unit operations, can affect the final microstructure. In the forming of ceramics, some of the major variables of injection molding are evaluated. Accurate measurement and control of these variables is emphasized for manufacture of Si3N4 ceramics with a high degree of reliability.

Jan 1, 1990

Projections of coal reserves in Central Appalachia are essential for long-term planning in the region. Annual production is declining in states such as Virginia. And minable reserves for the Central Appalachian coalfield are challenged by difficult geological, mining and market conditions. To project coal mining longevity in this region, interviews with mining companies were conducted to determine and assess technical and economic factors that affect coal seam minability. This information was ap- plied to seam and coal reserve data developed by state and federal governments. The results were analyzed to determine the effects of various factors on the overall minable coal reserve base.

Jan 1, 1998

This paper presents the latest developments in the flotation model being developed collaboratively between the Julius Kruttschnitt Mineral Research Centre in Brisbane, Australia, and the Mineral Processing Research Unit of the University of Cape Town in South Africa as part of the Australian Minerals Industries Research Association (AMIRA) P9 Project. It includes: - characterisation of flotation cells using the bubble surface area flux, Sb; - relationship of Sb to the overall flotation rate constant; - determination of the froth recovery factor; - evaluation of ore floatability; - modelling of entrainment - development of the Floatability Characterisation Test Rig (FCTR); - use of the model in design and optimization of flotation plants; and - current and future work.

Jan 1, 1999

By Pradip

The selection, testing, and commercial utilization of flotation reagents is best carried out in stages through microflotation tests on pure minerals and their synthetic mixtures followed by bench-scale batch flotation tests on the ore. A systematic approach to quantitatively evaluate different reagents, in particular, through the analysis of batch flotation data, has been presented in this paper. It is recommended that the reagents are compared both in terms of their performance with respect to the recovery-time as well as the recovery-grade plots. While the former describes the kinetic aspects of reagent interaction, the latter is a measure of its selectivity for a particular separation problem.

Jan 1, 1987