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By T. H. Chan

As the University of Hong Kong and their advisors planned their new Centennial Campus it became clear that they would have to re-provide existing water reservoirs on an adjacent site with new salt water reservoirs located underground in two new caverns. The existing reservoirs are owned by the Water Supplies Department who provide salt water for sanitary flushing and a separate potable water supply for regular use. Although underground reservoirs had not previously been adopted locally, the planning has been completed to a tight schedule and the construction is well advanced. The need to preserve historic buildings imposed constraints, as did the requirement to minimise potential construction nuisance for the local community and environment. This paper presents the background to the project and the work carried out to develop an innovative, sustainable and environmental acceptable solution. Construction progress to date is also presented.

By Yanping Xiao, Ton van Sandwijk, Gus Van Weert, Larry McHugh, Thomas Zabev

"All attempts to remove significant amounts of arsenic from enargite via neutral or reductive pyro routes have required operating temperatures between 600 and 700 º C, too high to propose an equipment development program. Operating at reduced pressures, or using hydrogen or elemental sulphur as a sweeping gas did not help to lower these temperatures. Admixing iron powder gave excellent results, but still required 700 º C. By fortuity, in recent experiments to produce tennantite from an enargite mineral sample, it was observed that enargite was completely converted to bornite, chalcopyrite with minor residual tennantite within an hour at 400-450 ºC. This is believed to be due to the presence of pyrite in the mineral sample treated. All earlier decomposition work appears to have been done on predominantly enargite (i.e. low pyrite) samples, or at high operating temperatures, ignoring possible reactions at lower temperature. The decomposition of enargite into iron substituted tennantite plus some bornite under evolution of liquid elemental sulphur, followed by further decomposition of this tennantite into bornite and volatile arsenic sulphides, appears experimentally feasible at these low temperatures and mimics described ore genesis pathways at > 250 ºC in saline solutions. We suggest two pathways to describe the observed experimental results:20 Cu3AsS4 + 12 FeS2 ???5 Cu10Fe2As4S13 + 2 Cu5FeS4 + 31 S(l)31 S(l) ???31 S(g) (evaporation)5 Cu10Fe2As4S13 ???10 Cu5FeS4 + 10 AsS(g) + 5 As2S3(g)"

Jan 1, 2014

By I M. Platten, S C. Dominy

The Clogau St DavidÆs gold mine has a recorded production of around 81 000 oz Au and it is the largest mine in the Dolgellau gold-belt and BritainÆs most prolific historical producer. The original mine was first worked for copper, however; in 1854, gold was found in waste material from the St DavidÆs section. In recent times the mine has operated intermittently between 1983 - 2007. The principal black shale-hosted gold-bearing reef (Main Reef) can be traced for about 3 km, striking approximately NE-SW and dipping steeply between 60¦ - 90¦ SE. The reef system pinches and swells, changes strike and splits into a number of smaller branches. Reef width is variable, ranging from over 6 m to a few cm and in places reducing to small irregular blobs. The reef is internally complex and composed of swarms of narrow (1 - 300 mm) subparallel veins separated by country rock sheets. The gold-bearing veins within the reef package are discontinuous; though generally possess bonanza grades running 10s - 100s oz/t Au. It has historically been shown that some gold-rich vein segments can grade up to 300 oz/t Au. The predictability of the gold-rich segments is poor, but has been shown to be related to presence of the Clogau (black shale) Formation, and/or the mechanical interactions of the reef with greenstone sills, reef branching and splitting and/or cross-fractures to form ore shoots. The mine is currently being re-evaluated as a potential small-scale selective operation.CITATION:Dominy, S C and Platten, I M, 2012. Geology, mineralisation and potential of the Clogau St DavidÆs mine, Dolgellau gold-belt, Gwynedd, Wales, in Proceedings Narrow Vein Mining 2012 , pp 101-120 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012

By Taylor G. H

The Triassic Ipswich (SE. Queensland) coals are of bituminous rank. The more exact rank of individual samples was determined by measuring the reflectance of the vitrinite. While in general the rank of the coals increases with stratigraphic depth, minor reversals, probably related to igneous intrusions, occur.The Ipswich coals form a coherent group so far as petrographic type is concerned. All are comparatively rich in vitrite and clarite, cutinite being the common maceral of the exinite group. The mineral contents of all the coals are comparatively high, clay and quartz being most abundant. The coals appear to be of essentially autochthonous origin, and to have been formed under conditions of fairly rapid subsidence.While the use of the coals is at present restricted to combustion, most have pronounced coking properties, as would be predicted from their petrographic composition and reflectance. However, the high mineral content of the coals would be a limiting factor in their use for coke-making.INTRODUCTIONDuring the last ten years, the Division of Coal Research, Commonwealth Scientific and Industrial Research Organization has carried out an extensive investigation of Australian coals, providing a wide range of analyses of most of the important of them. Special attention has been given in recent years to Queensland coals.Most seams were sampled as a number of subsections, enabling the internal variations, as well as the overall properties, to be assessed. The lenticularity of many of the mineralrich layers may tend to limit the significance of the samples, particularly in respect of ash yield, but although the vertical distribution of mineral matter may vary considerably from one sampling position to another, the lateral variation of the total mineral matter in the whole seam may not be great.Apart from extensive chemical analyses and utilization...

Jan 1, 1963

The reconstruction of the world after the present war must inevitably be profoundly influenced by the rise and progress of New China.The principle of Chinese mathrity has been admitted by Great Britain and the United States by their abjuration of extra-territorial tights, and by the withdrawal of the Maritime Customs Administration. The United States admits equality by her declaration that Chinese are eligible for American citizenship, and the reaction to this will be swift enmity to such peoples as may impose humiliating restrictions upon Chinese citizens.Finally, the decisions of the Moscow Conference and the recent meeting of National leaders in Cairo give partnership rights to this new State in post-war reconstruction, and open the way for a rapid realization of her destiny.It seems certain that China, if so she wills, can become, within a generation or so, one of the considerable forces of the world. The toad she wiII follow will be lighted by her own inherent and intrinsic genius. Her speed of progress can no longer be forcibly influenced by other nations and the attitude towards her of somewhat contemptuous patronage hitherto adopted by the European communities bordering the Pacific Ocean must be radically modified.It is doubtful whether the European will ever reach full understanding of Chinese mentality. The Chinese "way of life" since the dawn of her civilization has been totally divergent from that of the European, but the enormous potential strength, due to the simplicity of their requirements and their steadfast industry, is a function of that "way of life." On the other hand the trend of reorganization must obviously be towards Western standards; and a wide knowledge of the potential strength of the Chinese is possible and will be essential in our post-war world. The following, necessarily inadequate, notes are therefore offered, as an indication of the obstacles to be overcome and the capacity of the Chinese executives and operatives to overcome them.For 'thirteen centuries the political and social structure of China proper (ie, excluding Mongolia, Manchuria and Tibet) has been rigidly shaped by the philosophy of Lao Tze and the ethics' of Confucius. This Taoism, which is described as the "way of harmony" with its three jewels of character, gentleness, economy and humility, advocates the minimum of social, economic and political organization and still gives the key to the Chinese character.The Mongol and Manchu conquests of the 12th and 17th centuries, respectively, could hardly be dignified with the name of war, but the superior intelligence and harder mentality of the unwarlike Chinese finally absorbed...

Jan 1, 1944

By Olli Haavisto, Juha Timperi

"Accurate on-line assays of mineral slurries are the basis for effective operation of flotation circuits. Typically the elemental content measurements are obtained by an X-ray fluorescence (XRF) analyzer, which samples the process lines and performs the analysis concurrently line-by-line. For a more frequent measurement of each slurry line the XRF measurements can be complemented with reflectance spectrum information. In reflectance spectroscopy the absorbance properties of the slurry in the visible and near-infrared wavelength range are analyzed. The advantage of reflectance spectroscopy is that measurements can be obtained quickly and simultaneously from several slurry lines. However, since the shape of the spectrum is only indirectly affected by the slurry elemental contents, frequent calibration of the measurement against the XRF analyzer is necessary. This study elaborates the combination of reflectance spectrum analysis with XRF. Results of laboratory tests for different slurries are presented and the operation of the system in a copper-zinc flotation plant is demonstrated.IntroductionElemental analysis of mineral flotation slurries is the most important factor in evaluating the performance of concentration processes. Timely on-line assays are also used as the basis for controlling the circuits and ensuring that the grade and recovery targets are reached. X-ray fluorescence (XRF) is the dominant technology in on-line elemental slurry analysis, and typically centralized XRF analyzers are used. The advantage of a centralized analyzer is that one measurement probe can be used to acquire the data from several slurry lines. This reduces the overall operating cost of the system when compared to distributed analyzer system design with several measurement probes requiring maintenance and spare parts. Slurry samplers are installed in the interesting process flows and representative sample flows are brought to the analyzer, where the slurry is further sampled and measured consecutively by the XRF analyzer. Due to the centralized structure of the analyzers and consecutively measurement of the sampling lines the sampling interval per slurry line can be relatively long. In larger concentration plants with several sampling lines a typical assay interval is in the range of 10-20 minutes."

Jan 1, 2016

By E. O. Kirkendall

The investigation reported herein was undertaken to obtain data to supplement those presented in an earlier paper,l particularly for longer times at a higher temperature. This information may further develop our knowledge of the mechanism of diffusion in substitutional solid solutions. Diffusion of solute atoms interstitially dissolved is not difficult to visualize: it can take place without much disturbance of the solvent atoms. The mechanism of diffusion of solute atoms substitutionally dissolved is not so easily understood. Many theories have been advanced. Rosen-hain,2,3 Frenkel,4 Smekal,5 Langmuir,3,6 Steigman, Shockley and Nix,' and Johnson8 all proposed theories to explain diffusion. Langmuir's proposed mechanism consisted of a simple cyclic interchange of atoms involving an interchange in lattice positions of four or more atoms. This mechanism, accepted by the author at the time of his previous publication,1 and apparently quite generally accepted, required a net exchange in positions of both solute and solvent atoms in equal numbers. In other words, the rate of diffusion of the solvent and solute atoms would be the same. That this cyclic interchange in lattice positions of solute and solvent atoms in equal numbers is the only true mechanism of diffusion is denied by the evidence presented in this paper. Experimental Procedure This modification of similar procedure1 will be outlined briefly. The method consisted of the following steps: I. A pure Muntz metal (60.6 per cent Cu, 0.1 per cent total impurities) that was almost all beta brass at 780°C. was chosen. 2. The brass was turned between centers in a lathe to a diameter of 0.5965 inches. 3. After the brass was cleaned, it was electroplated with pure copper to a diameter of about one inch. 4. The sample was heated slowly to 400°C. under reduced pressure and held at that temperature for 4 hr. to remove occluded gases. It was then cooled to room temperature. 5. The sample was heated to 780°C. ± 3°C. and held at that temperature for different lengths of time; then quenched. Samples were cut off each time after quenching. Metallographic samples 1/4 in. thick were removed at I hr., 6 hr., 24 hr., 96 hr. and 701 hr. After 96 and 701 hr. samples of about I in. were removed for X-ray analysis. 6. The metallographic samples were polished on the cross section and photomicrographs were taken. 7. The I-in. samples were polished and etched on both ends. With the aid of a microscope each was carefully mounted in a four-jaw chuck in a lathe, so that they could be accurately bored for an arbor. 8. Turnings were taken for each X-ray sample. After each set of turnings, the sample was heated in an oil bath for about 1/2 hr. at 300°C. It was then etched in 25

Jan 1, 1942

By E. O. Kirkendall

The investigation reported herein was undertaken to obtain data to supplement those presented in an earlier paper,l particularly for longer times at a higher temperature. This information may further develop our knowledge of the mechanism of diffusion in substitutional solid solutions. Diffusion of solute atoms interstitially dissolved is not difficult to visualize: it can take place without much disturbance of the solvent atoms. The mechanism of diffusion of solute atoms substitutionally dissolved is not so easily understood. Many theories have been advanced. Rosen-hain,2,3 Frenkel,4 Smekal,5 Langmuir,3,6 Steigman, Shockley and Nix,' and Johnson8 all proposed theories to explain diffusion. Langmuir's proposed mechanism consisted of a simple cyclic interchange of atoms involving an interchange in lattice positions of four or more atoms. This mechanism, accepted by the author at the time of his previous publication,1 and apparently quite generally accepted, required a net exchange in positions of both solute and solvent atoms in equal numbers. In other words, the rate of diffusion of the solvent and solute atoms would be the same. That this cyclic interchange in lattice positions of solute and solvent atoms in equal numbers is the only true mechanism of diffusion is denied by the evidence presented in this paper. Experimental Procedure This modification of similar procedure1 will be outlined briefly. The method consisted of the following steps: I. A pure Muntz metal (60.6 per cent Cu, 0.1 per cent total impurities) that was almost all beta brass at 780°C. was chosen. 2. The brass was turned between centers in a lathe to a diameter of 0.5965 inches. 3. After the brass was cleaned, it was electroplated with pure copper to a diameter of about one inch. 4. The sample was heated slowly to 400°C. under reduced pressure and held at that temperature for 4 hr. to remove occluded gases. It was then cooled to room temperature. 5. The sample was heated to 780°C. ± 3°C. and held at that temperature for different lengths of time; then quenched. Samples were cut off each time after quenching. Metallographic samples 1/4 in. thick were removed at I hr., 6 hr., 24 hr., 96 hr. and 701 hr. After 96 and 701 hr. samples of about I in. were removed for X-ray analysis. 6. The metallographic samples were polished on the cross section and photomicrographs were taken. 7. The I-in. samples were polished and etched on both ends. With the aid of a microscope each was carefully mounted in a four-jaw chuck in a lathe, so that they could be accurately bored for an arbor. 8. Turnings were taken for each X-ray sample. After each set of turnings, the sample was heated in an oil bath for about 1/2 hr. at 300°C. It was then etched in 25

Jan 1, 1942

By C. S. Kucukkargoz, A. Bhalla

"The solid-state reduction of ilmenite concentrate with graphite was studied under argon atmosphere at temperatures between 1050°C and 1350°C. The rate of reduction increased with increasing temperature and decreasing particle size, with the maximum extent of reduction found to be 80% at 1350oC with a particle size in the range of -106 +90 µm. The activation energy for the reduction reaction was calculated to be 257 kJ/mole. The trivalent iron oxide was reduced first to divalent iron oxide and then to metallic iron. An annular ring of a partially reduced oxide phase containing metallic nuclei was formed around the core of ilmenite, which grew in size as the original ilmenite core shrank with progressive reduction. The reduction of titanium dioxide also took place during this stage, which produced the Magneli oxides in the form of TinO2n-1. The metallic phase had very high Fe and low Ti contents throughout the reduction, whereas the partially reduced oxide phase adjacent to the metallic phase was high in Ti and depleted in Fe. The metallic phase globules formed during this stage were small and are considered suitable only for leaching and not for other concentration processes. The core of the particle generally retained the composition of the original ilmenite. The purpose of this work was to remove iron and increase the titanium oxide content of the ilmenite to produce a high-titanium containing charge for subsequent smelting.IntroductionThe titanium-bearing minerals ilmenite (FeTiO3) and rutile (TiO2) are the primary natural raw materials used in industry to produce titanium metal and titanium-based products. The common titanium-bearing minerals are ilmenite, rutile, anatase, brookite, leucoxene, arizonite, and perovskite. Although the formula of ilmenite is commonly expressed as FeTiO3, the mineral can accommodate Mn and Mg, which are chemically bound in the form of (Fe,Mn,Mg)TiO3. Ilmenite concentrate can also contain Fe2O3 and Al2O3 in addition to the physically separable oxides such as SiO2 and CaO. The crystal structure of ilmenite is an ordered derivative of the corundum structure with a trigonal-rhombohedral symmetry. Fe2+ and Ti4+ ions occupy the octahedral sites, leaving the tetrahedral sites unoccupied. In each FeTiO3 unit, there are three O2- ions creating three octahedral sites, two of which are occupied by Fe2+ and Ti4+ (Wilson et al., 2005)."

Jan 1, 2017

By P. Zhang, S. Al-Thyabat

"Phosphate rock contains traces of rare earth elements (REEs) and can be a secondary source of these critical materials as large tonnages of phosphate rock are mined annually. Attention has mostly focused on the extraction of REEs from phosphogypsum, which contains more than 70 percent of the REEs reporting to phosphate concentrate, with only limited work conducted on REE extraction from sand tailings and slime even though they account for 16 percent and 15 percent, respectively, of REEs mined with phosphate matrix.In this work, phosphate flotation tailings were upgraded by gravity separation and froth flotation. Gravity separation was conducted using a laboratory shaking table, while flotation was conducted in a Denver D-12 flotation cell. The concentrated tailings were then leached by nitric acid followed by REE extraction with solvent and ion-exchange resin.The sand tailings were assayed as having 2.6 percent phosphate (P2O5 ) and 198.1 µg/g REEs. It was found that the shaking table could produce tailing concentrate assayed as having 8.6 percent P2O5 and 616 µg/g REEs but with only 20 percent REE recovery, while the froth flotation produced froth concentrate assayed as having 8.1 percent P2O5 and 368.2 µg/g REEs with 63.5 percent REE recovery. Leaching the flotation concentrate with 5.2 M (25 percent) nitric acid followed by extraction with solvent and ion-exchange resin yielded precipitates with REE contents of 0.926 and 0.314 percent, respectively, compared with 0.716 and 0.213 percent when table concentrate was used.IntroductionRare earth elements (REEs) consist of a group of 17 elements: the 15 lanthanides along with yttrium (Y) and scandium (Sc). They are rare not because of their scarcity in the Earth’s crust but because they are rarely found in economic and mineable deposits. REEs are called “seeds of technology” because of their importance to some critical technological industries such as renewable energy, hybrid cars, electronics and batteries. On average, an electric car or a hybrid car contains about 10 kg of REEs (Grasso, 2012; Radhika et al., 2011).REEs are usually categorized into light (LREE) and heavy (HREE). LREEs consist of lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pr), samarium (Sm), europium (Eu), gadolinium (Gd) and scandium (Sc), while HREEs consist of terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu) and yttrium (Y). About 200 minerals contain traces of REEs, but only three are considered economically significant: bastnasite, with the formula La,Ce(CO3)F; monazite, with the formula(Ce,La,Nd,Th)PO4; and xenotime, with the formulaYPO4 (Jordens, Cheng and Waters, 2013)."

Jan 1, 2016

By A.M. Edwards

1. Book reviews Platinum in South Africa, compiled by A.M. Edwards and M.H. Silk. Randburg, Council for Mineral Technology (Private Bag X3015, Randburg, 2125 South Africa), 1987. 55 pp. U$30. Reviewer: R.D. Wintle Scientific and technological developments in extractive metalurgy-G.K. Wiliams Memorial Volume. Parkvile (Australia), The Australasian Institute of Mining and Metalurgy, 1986. $A12 (incl. surface postage). Reviewer: T.Y. OweD Ion exchange and sorption processes in hydrometa/urgy, edited by M. Streat and D. Naden. Chichester, John Wiley & Sons, 1987. 229 pp. Reviewer: B.R. Green Role of Government in mineral resources development, edited by Michael J. J ones. London, The Institution of Mining and Metalurgy, 1985. 180 pp. £40. Reviewer: K.E. Ducat 2. Recent publications Annual report 1987. International Tin Research Institute, Kingston Lane, Oxbridge, Middlesex UB8 3PJ, England, 1988.Tin and its uses no. 156. Address as above. 3. Mintek reports Application Report no. 5 The production of and alusite and other refractory minerals. 1988. 16 pp. . Application Report no. 6 The development up to commercial application of a process for the recovery of lead, copper, zinc, and silver from the Black Mountain deposit. 1988. 14 pp.

Jan 1, 1988

The methods and equipment developed and used at the Mount Isa mine to obtain samples of uncemented hydraulic fill lying above major horizontal pillars are described. From existing underground development, samples were obtained at distances up to 50 m, of which up to 30 m was through hard rock. Samples were used to predict fill behaviour as it affected mining security during recovery of the pillars.Specialized equipment for difficult sampling situations and also other sampling exercises are described.

Jan 1, 1976

By T. I. Arbuzova

The present work presents the original data concerning using a high pressure torsion method and a shock wave loading technique to produce compact oxide nanomaterials and investigations of the effect of severe plastic deformation on a microstructure, crystal lattice and stability of these compounds. This allowed us to compare two ways of deformation action that can be characterized as quasi-static and dynamic effect, correspondingly. Particular attention was paid to a stoichiometry and surface composition changes upon severe plastic deformations. A procedure for studying chemistry of the oxide nanomaterials by means of nuclear microanalysis and Rutherford back scattering has been worked through. For surface studies the X-ray photoelectron spectroscopy has been used. It was shown that both distortion methods permit to produce massive nano-scale oxide materials from the coarse-grained powder during a single technological cycle. Bulk nanocrystalline materials based on LaMnO3, TiOy and ZrO2:Y2O3 were obtained by the quasi-static deformation technique. Nanoscaled ceramics of CuO, Mn3O4 and LaMnO3 were produced by the dynamic deformations. The density of the nanoceramics comes to 99%. Size effects and specific imperfection of the nanoceramics obtained lead to a set of particularities of physical properties.

Jan 1, 2006

By E. Ghali, W. Zhang, M. Robichaud, G. Houlachi

"The performances of six mesh and one plate dimensionally stable anodes have been investigated in the zinc electrolyte at 38oC and compared to conventional silver-lead alloy anodes. The electrochemical behaviour of these anodes was studied by cyclic voltammetry, galvanostatic, potentiodynamic, open circuit potential and electrochemical noise measurements. It was observed that at the end of 24 h of galvanostatic polarization at a current density of 50 mA/cm2 in the zinc electrolyte at 38oC, the mesh V had the lowest potential followed by mesh III, mesh VI, plate-V, mesh IV, mesh I, and mesh II electrode. When the potentials for mesh I, mesh III, mesh IV, VI and plate-V, mesh V were compared with that of the Pb-0.7%Ag anode (1920 mV/SHE), they were found to be 6%, 16%, 7% 10%, 17% lower, respectively.After 16 h decay following the 24 h polarization, the mesh III had the lowest corrosion rate (51 mS/cm2) among the seven specimens, followed by the plate-V, mesh V, VI, IV, I and II (221 mS/cm2). For the fresh surface as received, after two hour open circuit potential measurements, mesh I had the most positive (noble) potential (1382 mV/SHE) among the seven electrodes followed by the plate-V electrode, mesh V, mesh IV, mesh VI, mesh III and mesh II (751 mV/SHE). After consecutive series of electrochemical testing, mesh V, mesh III, mesh VI had lower corrosion rates (~ 343± 6 µA/cm2) than that of mesh IV, mesh I, plate-V, and mesh II (~ 644± 143 µA/cm2).INTRODUCTIONThe continued use of lead based anodes in the electrowinning process has been mainly due to their relatively low cost as compared to other materials (Msindo, Sibanda, & Potgieter, 2010). They have good electrical conductivity, stability during electrolysis, very good corrosion and wear resistance (Ivanov, Stefanov, Noncheva, Petrova, Dobrev, Mirkova, Vermeersch, & Damaerel, 2010). However, lead-based anodes give their high energy consumption and low corrosion resistance for electrowinning. To overcome these problems, Dimensionally Stable Anodes (DSAs) has been chosen (Msindo et al., 2010). Comparing to the traditional lead anodes, the DSA anodes have many advantages: (1) no contamination; (2) no loss of anode material, pure electrolyte; (3) lower gas bubble effect through special anode designs; (4) use of higher current densities (Msindo et al., 2010). The success of DSA anodes has been attributed to their chemical stability that allows them to maintain nearly constant dimensions during the life of the anode even when operating in environment with low pH values. Due to their stability, the consumption rates of DSA are as low as 1 mg/amp.y (Alfantazi & Moskalyk, 2003)."

Jan 1, 2016

By Lon D. Santis

This paper describes a lightning warning system (LWS) in operation at the U.S. Bureau of Mines' (USBM) Pittsburgh Research Center (PRC) from December, 1989 to April, 1991. An electric field mill measured the DC atmospheric electrostatic field. Also, an economical on-line weather data service provided lightning location maps and other weather information. A system such as this can significantly improve the safety of explosive handling. The use of these two methods addresses the detection of thunderclouds building overhead and the prediction and tracking of developed storms. Warning reliability of the system was very good when data from both sources were considered. Experience showed, however, that use of either system alone would not provide adequate reliability in most situations. Some problems occurred with the field mill and there is some question whether the instrument is compatible with harsh mining environments or could be made portable. Another method ' of measuring electric field based on fiber optics is discussed. This technology may be able to overcome the problems with field mills.

Jan 1, 1993

Last year in the US alone, about 425 Mt (468 million st) of minerals and coal were beneficiated by froth flotation. This number indicates that from 1983 there was a 10% increase in tonnage of min¬erals and coal beneficiated by the indus¬try. A significant improvement was seen in the tonnage processed by the nonferrous minerals and coal industries. BP Minerals America installed 85 m; (3000 cu ft) flotation cells at the Bing¬ham Canyon mine and concentrator. The new flotation circuit has fewer than 100 cells compared to 2000 flotation cells used in the old plant (Mining Engi¬neering, November 1988). Column flotation use on a commer¬cial scale continues to expand as seen from the interest expressed at the Col¬umn Flotation Symposium (Column Flotation '88). The Magma Copper Co., San Manuel Division replaced all con¬ventional cells with 1.8 x 12 m (6 x 40 ft) column flotation cells for copper con¬centrate cleaning. Also, 1220 mm and 760 mm-diam (48 in. and 30 in.-diam) column cells are operating at the plant in the molybdenum circuit. A commercial Diester Flotaire col¬umn cell for fine coal recovery was installed at the United Coal Wellmore No. 20 plant. The 36.8 m3 (1300 cu ft) cell recovers 13.6 to 18 t/h (15 to 20 stph) of -590 gm (-28 mesh) coal. A similar unit has been installed at Tanoma Mining Co. in Pennsylvania. Various modifications of the column cells are being designed around the world. Jameson (Mining and Metal¬lurgy, 1988) described a new concept whereby the feed and air stream mixture is discharged into a cylindrical column of about 1.2 m (4 ft) height. Recovery and grade of nonferrous minerals have been reported to be better than that in a four-stage conventional flotation clean¬ing circuit. Flotation reagents American Cyanamid and Dow Chemical continued development of a new generation of sulfide collectors. A general feeling is development of new sulfide collectors has not kept up with flotation technology. Additionally, joint efforts between industry and chemical suppliers will likely be necessary to realize the economic benefits of the new technologies, since new chemistries respond differently compared to the conventional collectors. Flocculant development in recent years has been evolutionary rather than revolutionary. Rothenborg reported on development of a new flocculant family (a hydroxymated polyacrylamide desig¬nated S-6703) that has shown consider¬able promise in red mud clarification. Plant testing showed that this new floc¬culant could replace starch and poly¬acrylate and provide significantly higher overflow clarity. Barol Kami (Siirak) and Cleveland¬Cliffs (Hancock) reported development of an amphoteric apatite collector (ATRAC 873) that was used in Tilden's silica flotation process to increase apatite rejection. The collector was engineered for the particular flotation conditions in the complex Tilden process. Significant plant testing with ATRAC 873 showed that this reagent gave significantly in¬creased apatite rejection without any effect on silica flotation effectiveness or selectivity. Electrostatic separation Electrostatic separation is now em¬ployed in the precious metals mining industry to recover gold and silver grills from crushed slag. The installation at Paradise Peak has prompted other op¬erators to consider this application. In another development, attractive potentials for treating very fine minerals (-45 µm or -325 mesh) are being devel¬oped by Advanced Energy Dynamics and by the Department of Energy. Demonstration tests using triboelectric charging/electrostatic separation have been successful on a variety of minerals as well as coal. Magnetic separation Developments in magnetic separa¬tion have transpired on a production scale. Superconducting, high gradient magnetic separation has gained accep¬tance with the successful startup of a second unit treating kaolin at J.M. Huber Corp. This liquid-helium-cooled mag¬net generates 2.0 tesla in a 3-m-diam (120-in.-diam) bore with no power con¬sumption. Wet, high-intensity magnetic separation has been applied to sulfide mineral separations both domestically and abroad. These continuous type of separators are effective in removing residual chalcopyrite and sphalerite from other base metal sulfide concentrates. Separators using high energy rare earth permanent magnets are continu¬ally increasing. Now offered as both drum and roll type, these units are be¬coming a staple in the processing of industrial minerals. Tests using rare earth magnets strategically placed on a spiral concentrator have demonstrated the enhanced recovery of heavy miner¬als such as ilmenite. Classification Although no major technology break¬throughs in classification appear immi¬nent, there is an increasing need for more efficient and cost-effective meth¬ods to make size separations. It is be¬coming more apparent that mineral concentration methods will be more common at very fine sizes, say below 50

Jan 1, 1989

The 2003 SME Annual Meeting and Exhibit will take place Feb. 24-26 in Cincinnati, OH. The meeting will feature a host of special symposia and programming geared toward the industrial minerals and aggregate industry sectors. This programming focus is particularly relevant for this annual meeting, as it will be hosted in the center of America’s transportation hub and industrial mineral center. Cincinnati, located on the Ohio River, is key to the movement of America’s supplies and construction material needs.

Jan 1, 2003

By R. Mensah-Biney

The aqueous biphase separation process (ABS) has been used to separate ultrafine industrial minerals. The partition behavior of TiO2, Al2O3, Fe2O3 and kaolin was not pH dependent. The partition behavior of SiO2 was, however, pH dependent. The partition coefficient of kaolin in PEG 3400/ Na2CO3 biphase system was = 150 and that of the silica in the same system was = 0.02, resulting in a separation factor of = 8500 between kaolin and silica. The aqueous biphase separation system was used to separate free silica from kaolin in a raw clay sample from Mexico. The partition behavior of mica, feldspar and clay from North Carolina was also evaluated.

Jan 1, 1999

By N. Kumar, A. K. Dhawan, A. Varughese, S. K. Khullar

Abstract The in-situ stress field is one of the primary parameters influencing the performance of underground structures particularly in the Himalayas where there is strong influence of topography and geology on in-situ stresses. It is always advisable to measure the in-situ stresses, in whatever best way possible. Hydrofracturing is one of the methods by which in-situ stress can be measured. This paper briefly describes details of the concept of Hydrofracturing in arriving at the in-situ stresses of the rock mass at Pancheswar Project. The data obtained from the tests has been analysed, interpreted and the results are presented in this paper. Kurzfassung Das Spannungsfeld an Ort und Stelle ist einer der wichtigsten Parameter, die das Verhalten der Untergrund-Struktur beeinflussen, insbesondere in den Himalayas, wo die Topografie und die Geologie einen grossen Einfluss auf die oertlichen Spannungen ausueben. Es empfiehlt sich stets die Spannungen an Ort und Stelle so gut wie moeglich zu erfassen. Die Hydrofraktur bzw hydrografisches Zerstueckeln ist eine der Methoden, die bei den Messungen der oertlichen Spannungen verwendet werden koennen. Diese Abhandlung beschreibt kurz Einzelheiten ueber das Konzept von Hydrofraktur bei der Bestimmung der Spannungen an Ort und Stelle von der Felsmasse bezueglich des Projekts Pancheshwar. Die gewonnenen Daten aus den Messungen wurden analysieret und ausgewertet. Die Ergebnisse werden dabei vorgelegt. Sommaire Le champ de contraintes in-situ est un des paramèters principaux influencant l’exécution des structures souterraines particulierèment en Himalaya où les forces in-situ sont fortement influencées par les caractéristiques topographiques et géologiques de la région. La fracturation hydraulique est une technique qui permet de mesurer des forces in-situ des massifs rocheux. Cet article décrit brièvement le mécanisme de fracturation hydraulique et présente les résultats de mesure des forces in-situ des roches au site du projet hydroélectrique de Pancheswar.

Jan 1, 2003

Coal Preparation Research at Turkish Coal Enterprises (TKI)

Sep 13, 2010