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Zircon is extensively used as moulding sand in the production of steel and high-duty iron castings. To achieve a satisfactory grade of zircon concentrate, the zircon particles may need ,to have surface coatings removed, as such coatings can hinder electrostatic and magnetic separation of zircon from associated minerals. Xn addition the presence of surface coatings on the zircon. particles can cause sinterins and fusion of the zircon to the east metal resulting in "burnt-on" sand or fritting of the casting. "Burnon" necessitates cleaning of the casting by grinding or chipping, which is expensive and results in loss of definition on the casting face.Hudson (1966) has pointed out ,that some coatings on mineral sands are lightly-adhering clays which can be removed quite readily by agitating the sands in water for a few minutes-thus their removal constitutesno problem. However, the heavy gingery coloured coating which adheres strongly to the surface of the particles in some deposits, and which has generally been considered to be a form of iron oxide (Baker, 1962; Hudson, 1966), cannot be removed effectively by attrition cleaning in water (Hudson, 1966). Such coatings limit the usefulness of these concentrates in the foundry industry.An investigation of strongly-adhering coatings on "ginger zircon" concentrates from the Yoganup deposit of Westralian Sands Ltd has shown that the stain consists of a cemented mixtvre of hydrated iron and aluminium oxides and kaolin minerals, and that it can be removed by a relatively low cost treatment.IDENTIFICATION OF THE STAIN BY XRDX-ray powder diffraction (XRD) patterns were obtained from small samples of stain scraped, individually, from the surface of hand-picked zircon and ilmenite crystals. These scrapings were mounted on quartz fibres and exposed to CoKa radiation in a 57 mm Debye camera. To avoid heavy fogging of the x-ray films, a substantial amount of the iron oxides was preferentially leached from the scrapings (before mounting) with an ammonium oxalate-oxalic acid solution (Rooksby, 1961). The residual material gave a fairly well resolved powder pattern (Table 1). A...

Jan 1, 1975

It is suggested that if adequate knowledge is available about classifiers in closed grinding circuits, these units may be used as on-stream size analysers when equipped with suitable sensing devices. Research work which is at present in progress to enable a hydrocyclone to be used for this purpose is discussed.

Jan 1, 1967

By L. Dison

This technical note is issued in two parts, as follows: Part I, after a brief introduction, discusses the value of patents and the law of patents, including patent applications and the exploitation of inventions. This is followed by some comments for the benefit of would-be inventors and potential users of patents. Part II, which will appear in the February issue of this Journal, focuses on the mining industry and then discusses views on patents that were Quoted in Part I. The last section makes recommendations as to how II1ventors and users (including mining authorities) should handle patents.

Jan 1, 1992

By L. Dison

This technical note is issued in two parts as follows. Part I, which appeared in the January issue of this Journal, after a brief introduction, discusses the value of patents and the law of patents, including patent applications and the exploitation of inventions. This is followed by some comments for the benefit of would-be inventors and potential users of patents. Part I focuses on the mining industry and then discusses views on patents that were quoted in Part I. The last section makes recommendations as to how inventors and users (including mining authorities) should handle patents.

Jan 1, 1992

By Rao P. K, Sahoo P. K

The main constituents of ferromanganese slags are silicates of Mn, Ca and AI. Factors affecting the recovery of manganese from a low manganese content ferromanganese slag (about 16 per cent MnO) during acid leaching were studied. These included time, temperature, agitation, sulphuric acid addition, solid:liquid ratio and particle size. Agitation rates greater than 300 rev/min. leaching periods greater than 30 min and temperatures above ambient were found to have no effect on Mn recovery. Dissolution of Mn was found to be highly dependent on the amount of acid added.About 90 per cent of the Mn was recovered when 5·5 times the stoichiometric amount of acid was used. About 28 per cent of the Mn was recovered when the stoichiometric quantity of acid (with respect to Mn alone) was used. However, the recovery increased to about 75 per cent when the total stoichiometric requirement of acid with respect to Ca, Al, Mg and Fe as well as Mn was used for leaching. The extent of Mn dissolution also depended on the particle size of the slag. The percentage of Mn recovery (using 5·5 times the stoichiometric amount of acid) increased from about 60 per cent to about 92 per cent when particle size decreased from -36 +52 to -150 +200 mesh (B.S.S.). When the results of this study were compared with those in a previous study involv,ing the leaching of a high manganese content slag (containing about 40 per cent MnO) results were similar except that there was a gr-eater consumption of acid in the present case (i.e. low manganese content slag).

Jan 1, 1979

By Giannini L. M

A method using dynamic programming for solving the optimum pit limit problem was presented in an earlier paper. A recent issue of this journal contained some contributed discussion on the implementation of this technique. In this paper we provide some additional ideas and possible options one can incorporate into the method. In particular, an efficient procedure for obtaining further optimum pit outlines on extensions of the original block model is described.

Jan 1, 1987

By Rodrigo Serna, Nora Schreithofer, Zoltan Javor, Kari Heiskanen

"Mineral floatability is a function of mineral properties such as size, liberation, shape, surface composition, reagent coverage on the surface, level of oxidation on the surface, etc.; pulp chemistry: Eh, pH, temperature, DO, reagent type, etc. and hydrodynamic conditions: turbulence, gas dispersion, D32, etc. The biggest challenge with predicting the floatability of an ore is finding a measurement method that would take into account the effect of all of the variables on the floatability of the minerals. The particle-bubble attachment time measurement is considered as an alternative way to predict the floatability of minerals instead of using expensive and time consuming flotation tests because it takes into considerations both surface chemistry and hydrodynamic parameters present in the froth flotation. The existing particle-bubble attachment time method is suitable for studying some significant flotation variables such as pH, temperature, particle size, reagent type and concentration. Nevertheless, measuring the attachment time as a function of collector coverage or surface oxidation is much more challenging. This paper introduces a new induction timer designed to measure the effect of galvanic interaction on the attachment time of particles. The new setup employs an array of needles to create 6 bubbles with the average size of 2.1 mm. Imaging system is used to set the initial distance between the particle bed and the array of bubbles. The attached particles are collected and sent for further analysis. One of the main benefits of the new experimental setup is that the attached particles can be physically separated from the unattached particles therefore many of the particle properties can be analysed and evaluated.INTRODUCTIONSchumann (1942), and Tomlinson and Fleming (1963) proposed that the flotation rate constant is dependent on four probabilities: particle-bubble collision (PC), particle-bubble attachment (PA), particlebubble aggregate stability in turbulent environment (PE), and particle-bubble aggregate stability in froth phase (PF). Any change in any of these probabilities will affect the overall flotation rate constant. All of the above-introduced probabilities are influenced by stream- variables and mechanical variables but their extent of influence vary. The stream variables are particle properties that have been shown to affect flotation rate constant such as size, shape, liberation, mineralogical composition, reagent surface coverage, surface oxidation, etc. The mechanical variables are the direct and indirect properties of the flotation unit affecting flotation rate constant such as cell and impeller geometry, air rate, impeller speed, air holdup, bubble size, residence time, hydrodynamics, froth depth, etc. For instance, the probability of collision is affected by many mechanical variables (bubble size, hydrodynamics, bubbles holdup etc.) but only one stream variable (particle size) has a major effect on it. On the other hand the probability of attachment is affected by much more stream variables: particle size, shape, liberation, surface composition, particle surface oxidation and collector coverage, Eh, pH, etc."

Jan 1, 2016

By Turner T. M

The problem of metering fine particulate material at low flowrate is often encountered in metallurgical experiment. This note describes a feeder which wa developed to provide metered flows of copper sulphide concentrate in the range of 0'1-0'7 g/min.It is believed that the present device is easier to operate than previously described feeders (e.g. Hamor and Smith, 1971). It may have applications in the field of analytical chemistry, as well as in metallurgical investigations.

Jan 1, 1978

About 11,000 tons of contaminated zinc flotation concentrate were available in the form of earth walls from dams used for atmospheric drying of the concentrate.Following successful laboratory tests this material was treated in a plant by crushing, grinding, and then flotation in a circuit consisting of roughing, scavenging, and two stages of cleaning. Reagents used were copper sulphate and a little butyl xanthate and frother. About 5,720 tons of zinc concentrate assaying 52· 3 per cent zinc were produced.

Jan 1, 1968

By M. J. Sapko

The US Bureau of Mines conducted, through joint funding with the Colorado Mining Association, large scale oil shale rubble fire tests to investigate flammability characteristics and different methods of extinguishment. Ignition of large rubble piles was easily accomplished. Foam blankets could he used to control surface flames. The results of these large scale tests confirmed that water was effective but not particularly efficient in extinguishing deep seated oil shale fires. It took up to 1.7 times as much water to extinguish afire as anticipated on the basis of a simple cooling model, assuming 100% utilization.

Jan 1, 1990

By K. Hansson, A. Jedborn

Background In the mining industry, conversion of fine particles into a slurry is often part of the normal processing of the ore. Therefore, from a system's point of view, slurry transporta¬tion would be considered as a natural alternative, all the way from the working face to the final processing. In underground mines, there is sometimes a considerable inflow of ground water that has to be pumped out. When the mine dewatering installations are integrated with a hydraulic hoisting system, the cost of power needed to pump out the ground water can be excluded from the cost of hoisting, compared with other modes of transporting the solids to the surface. The chief advantage of hydraulic hoisting is that the hoisting capacity can be increased at comparatively low total cost without necessitating the sinking of new shafts. Alterna¬tive examples include deepening of the existing mechanical hoisting system, truck, or conveyor belts transport in ramps to the present level. These often become very expensive. The economic effectiveness of hydraulic hoisting and hydraulic design considerations have been discussed by Kostuik (1965) and Sellgren (1985, 1986) for both small shallow mines and large deep underground mines. Objective and scope The objective of this study was to demonstrate the feasi¬biliy of hydraulic hoisting in hypothetical examples of mine deepening. Underground grinding to a maximum particle size of about 700 um (about 25 mesh) is considered. The pumping of ground ore products with positive displacement plunger or membrane type of pumps at working pressures of up to 15 MPa (2200 psi) is a thoroughly tested technique (Venton, 1986). Hydraulic hoisting system A hydraulic hoisting system is described schematically in Fig. l . The ore is mined, handled, and crushed conventionally. It is then ground wet underground. The slurry is then tempo¬rarily stored in an agitated tank and pumped to an agitated receiving tank on the surface. The ore is then further processed in the concentrator. The capacity of a pipeline is very high. For example, an annual production of 500 Kt (550,000 st) of ore can be handled in a 100-mm-diam (4-in.-diam) pipeline. Systems layout - economic effectiveness Schematic mine layouts are presented that represent situ¬ations where hydraulic hoisting often is the most economical alternative. A situation where the ore is trucked to the level of the existing hoisting system is shown in Fig. 2 (following page). With hydraulic hoisting, only a shaft for ventilation, pipe¬line, and personnel are needed. In a first phase (Fig. 2), a hydraulic hoisting installation with crushing and grinding units, storage facilities, and pumps has been located at a level of about 400 to 600 m (1310 to 1970 ft) below the surface. With further development of the mine, the hydraulic hoisting

Jan 1, 1989

By Rudolph G. Wuerker

The scarcity of values of tensile strength of rocks has been explained by the lack of successful testing procedures. In the case of mine rock a description is given' of the difficulties encountered in testing a cylindrical specimen, such as a core, by conventional methods. Over a period of years the following method has given definite and reproducible results with the weakest as well as with the strongest rocks. It does not completely supersede the use of cores with special fixtures but is a supplement in all cases where cores cannot be obtained, as from soft rocks, or in cases where it is less expensive to prepare test specimens by cutting them out of the rock instead of drilling cores.

Jan 2, 1955

By D. W. Fuerstenau

Measurement of zeta potentials is a useful tool to study the surface chemistry of minerals under flotation conditions. Because there is continued interest in this approach, the apparatus for obtaining zeta potentials of nonconducting solids by the streaming potential method is outlined here. Fig. 1 illustrates the streaming potential apparatus. The streaming potential cell or plug consists of two 24/40 standard ground joints (4) joined with a piece of pyrex tubing 60 mm long and 12 mm in diam (5). The electrodes are made of bright platinum disks 19 mm in diam and 1 mm thick through which 0.5-mm holes have been drilled (6). To the surface of each is welded a piece of 80-mesh platinum gauze. Each electrode is permanently mounted on the ends of the inner parts of the two standard joints by means of a platinum wire (7) which connects it to the tungsten seal at the end of the cell (8). For ease in cleaning and handling the apparatus, the streaming cell is fastened to the 500-ml reservoir flasks (1) by means of two 18/9 ball and socket joints (2). This particular arrangement permits passage of the solution in either direction through the plug of particles. Flow of solution can be stopped by a stopcock (3). One of the reservoir flasks has a large opening to permit insertion of either a thermometer or a pair of electrodes for measuring pH of solutions within the system. In making the experiments, the plug is filled with 48 to 65-mesh particles, but a layer of 28 to 35-mesh particles is placed at each electrode to prevent any of the finer particles from passing through holes in the electrodes.

Aug 1, 1956

By Stephen Krickovic

As it is commonly understood in the bituminous coal mining industry, pillaring means removal, as completely as is practical, of all pillars formed in the development of headings and rooms on first mining. The degree to which this can be accomplished, termed percent of recovery, is of course dependent generally upon the physical conditions of the bottom and the overburden, the system of min-

Jan 2, 1955

By R. G. Reddy

Iron solubility's in spent pickling (HFHNO3 -H2O) solutions were determined as a function of HF and HNO3 acid concentrations. A chemical analysis of the industrial pickling solutions and sludges was performed. The stable phases observed in the sludges are FeF3.3H2O and (FeCr)F3.3H20. Pure Fe metal, AISI 316 stainless steel and AISI 416 stainless steel were used in this study. The results show, that the solubility of Fe increased as the concentrations of HF increased in the pickling solution at a fixed concentration of HNO3. A reasonable agreement between the experimental solubility data and the theoretical calculated data was obtained. X-ray diffraction analysis showed that the solid solubility product formed in the ternary solution containing pure Fe is mainly, at a high pH value, FeO(OH) compounds and, at a low pH value, Fe F3.3H2O compounds.

Jan 1, 1994

By Field R. V, Graieg O, George T. J

The design, construction and operation ofa laboratory scale rotary pot kiln are outlined. Charges ofup to 3 kg can be heated to temperatures up to 1200°C in a controlled atmosphere. Some examples of pyrometallurgical investigations carried out using the kiln are briefly described, including thermal reactivation ofcarbon using steam at 550-850°C, high temperature testing ofkiln liners for corrosion resistance to fluoride, and calcination oflimestone. Results obtained from these trials allow either direct scale-up to the Engineering Chemistry Laboratory's pilot-scale (50-100 kg/hr) rotary kiln or modifications to be made to commercial scale processes and/or equipment.

Jan 1, 1986

A mineral grain finder is described which is easily constructed to fit onto the stage of a standard reflected light ore microscope.The device is most useful in relocating particular grains or mineral associations on 30 mm diameter polished sections. The use of the grain finder in the teaching of ore microscopy is outlined.

Jan 1, 1988

This technical note describes a problem with WANG82, a ventilation network analysis programme. The problem was highlighted by Renison Ltd when using the programme on large, complex networks. Under certain circumstances the programme produced incorrect results or failed to converge to a solution.

Jan 1, 1986

By Poi G, Madgwick J. C, Davis P, Pannowitz D, Cho D, MacKay B, Chan S. M, Varga R. A, Chun U

Periodic dilute sulphuric acid treatment ofstill, batch-fed, molassesenriched, microaerobic, manganese-dioxide-Ieaching microbial cultures led to marked improvements over untreated cultures. Percentage Mn++ recoveries increased (7X), rate of Mn++ formation improved (3X) and yields of Mn++ per molasses use were more economical (5 X). The yield in terms of molasses used improved with decreasing sugar used (eg 1.17 g Mn++/gram molasses at 0.2 per cent molasses (w/v) feed and 24 per cent (w/v) pulp density MnO2 tailings). The most effective Mn++ leaching in terms ofpercentage recovery (97 per cent) and rate ofleaching (46 mg Mn++/day) was at 0.5 per cent molasses (w/v) and 14 per cent pulp density (w/v) MnO2 tailings.

Jan 1, 1986

By Pollard D, Meadows N

The presence of impurities which are electropositive to zinc in acid zinc electrolyte causes changes to deposit morphology and reduced current efficiency. Glue may be added to control some impurity effects, but assaying for animal glue concentration is difficult and seldom done. Measurement of the activation overpotential for zinc deposition by cyclic voltammetry is used in some plants to monitor electrolyte quality and control glue additions.The deposit morphology and current efficiency of zinc deposition from commercial electrolyte were investigated for various glue additions in the presence of increased levels of antimony. Cyclic voltammetry was investigated as a method of optimising glue additions in the presence of antimony.Scanning electron rnicroscopy showed deposits characteristic of the impurity element present and the glue addition rate. Cyclic voltarnmetry measurements showed some correlation between current efficiency and activation polarisation potential. The importance of using tankhouse electrolytes where results are to be related to tankhouse operation was noted.

Jan 1, 1988