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By G J. Sparrow, M J. Fisher-White

A mineral and chemical characterisation study was conducted on ilmenite-rich heavy mineral concentrates sourced from the western sector of the Eucla Basin in southern Australia. Test work involved using X-ray diffraction (XRD), scanning electron microscope (SEM) and electron microprobe-based characterisation methods. Results showed considerable variability in the degree of ilmenite alteration between deposits with TiO2 contents varying from 53 - 63 wt per cent TiO2. Notwithstanding variability between individual deposits, the samples all had [Ti]/[Ti+Fe] ratios >0.5 consistent with a mineral assemblage of hydrated ilmenite or the hydrated, Ti-rich alteration phase pseudorutile (Fe3+2-x Ti3O9-3x (OH)3x). Accessory phases consisted of rutile (primary and secondary), zircon, aluminosilicates, quartz, Fe oxyhydroxides and spinels. Results for the most altered material are broadly comparable with data for ilmenite concentrates from the eastern margin of the basin. The mineralogy of the western Eucla Basin concentrates and the minor element composition of the ilmenite grains suggest they could be upgraded to synthetic rutile by a modified Becher process.

Jan 1, 2008

By André Mans, Frans B. Waanders

"Ferrosilicon (Fe-Si) is an important commercial material and it forms the basis of the powder used in dense medium separation (DMS) of various minerals in a minerals beneficiation process. Current losses of Ferrosilicon (Fe-Si), which is used in the dense medium separation (DMS) of iron ore at Kumba Resources, Sishen, South Africa occur due to adhesion to the separation products and also by being present in the effluent stream, due to abrasion. The losses contribute greatly to the running cost of the plant and the purpose of this project was to determine the characteristics of the unused Fe-Si and then to characterise the changes that occur during storage and the use thereof.A Scanning Electron Microscope (SEM) and Mössbauer Spectroscopy (MS) were used to investigate the characteristics of the fresh and used Fe-Si. The SEM analyses of the Fe-Si yielded a composition of 15 wt.% Si and 85 wt.% Fe with minor impurities of Mn and Cr (<1 wt. %), resulting in an ordered phase with a calculated composition of Fe2Si. The average density of the Fe-Si was found to be 7.177 g.cm-3 whilst the size distribution was determined with the d50 of the particles being approximately 30 µm. A slurry, containing 10% solids was prepared, which had a density of about 1.1 g.cm-3 and this slurry was used to conduct the various experiments under laboratory conditions at the university. Samples were taken at regular intervals from a storage container containing a lime solution as well as from a closed circulation circuit system, kept at a constant temperature of about 60°C. Mössbauer Spectroscopy yielded, for the new fresh Fe-Si-samples, a two-sextet spectrum with hyperfine magnetic field strengths of 19.9T and 30.7T respectively, and the yellow-brown froth was found to be akaganeite or ß-FeOOH.It was found that the biggest loss of Fe-Si was due to the abrasion of the particles during the DMS process. A possible change in magnetic properties was also observed, leading to further losses that could occur during prolonged use of the medium. No clear changes to the Fe-Si occurred during correct storage methods, as was initially thought."

Jan 1, 2003

By Ben L. Seegmiller

The basic compression-yield concept of roof support for mine roadways requires that the mine roof be placed in a state of compressive stress. The compressive stress may be achieved using a support system such as an entry truss or other specialty truss device. Furthermore, the roof must be allowed to yield, but with great resistance when abutment loads are placed on the roadway. The resisted yielding may be provided using a new yieldable steel prop, known by the trade name, YIPP~. The yieldable steel prop can allow as much as 1.5 m[5 ft] of yield, or up to approximately 40% of the opening height, while providing a resistance in excess of 60 mt[66st]. More than fifteen mining operations including coal, trona and hard rock mines have field tested the YIPPI . Present results indicate that the yieldable prop provides a cost-effective alternative to wood cribs, concrete cribs, hydraulic props and other steel prop supports. The paper describes the YIPPI including its unique principle of operation, its applications and actual field performance.

Jan 1, 1992

By Lewis A. Riley

I desire to submit, for the consideration and information of the members of the Institute, the following data, drawings, and tables, showing what I believe will be interesting information with regard to the diamond drill, and its uses in developing mineral lands. I would first say that the results given have been obtained during the past two years by means of two drilling machines belonging to the Lehigh Valley Coal Company, operating on their coal lands in the Mahanoy, Lehigh, and Wyoming regions. 1st. A tabulated statement, giving location of borings, date, progress, total cost, itemized cost per foot, etc. 2d. Section showing strata bored in Nos. 5 and 10 holes at Mt. Carmel, see Plate VI. 3d. Section showing strata bored in No. 19 hole at Hazleton, see Plate VI. 4th. Photograph and description of drill No. 2. From the first it will be seen that the total number of test-holes bored up to May 1st of this year is 24; 9 of these are in the Mahanoy region, 6 in the Lehigh region, and 10 in the Wyoming region, in all of which cores have been taken for the whole distance. The total distance bored is 9902 feet. The majority of the holes have been put down for the purpose of proving the lower veins of the coal series, and have had to encounter the harder rocks of the coal formation. Much of the distance has been through the lower conglomerates, going in some cases through the coarse egg conglomerate, the foundation of the coal deposit, and to the green sandstone and red shale which underlie it. These lower sandrocks and conglomerates are among the hardest known to geologists, and present a formidable resistance to the exploring drill. This fact must be taken into consideratiotl in comparisons of cost of drilling, and when considered will still further improve the very favorable results I am able to show in my statement of costs. In illustration, I will cite the work of one bit when boring in the upper or softer rocks of the Wyoming region, where 280 feet were obtained without resetting, while in the Lehigh and Mahanoy regions, in the lower and harder rocks, bits set with the same quality of diamonds would only bore from 3 to 20 feet before being worn out. In this connection it may

By Frank D. Lamb

Pyrophyllite, a hydrous aluminum silicate (Al2 Si4O10 (OH)2 ) has been mined in North Carolina and marketed without beneficiation for the past 100 years, but recent demands for higher-grade material indicate that an economical concentration method is needed for at least a part of the pyrophyllite production. Past production has depended upon selective mining and hand sorting, which is often unsatisfactory because of the finely disseminated character of the ores. The major impurity in North Carolina pyrophyllite ores is quartz, which accounts for the abrasiveness of the commercial product. Since pyrophyllite is only slightly heavier than quartz, those ores cannot be beneficiated by simple gravity-concentration methods. Some separation can be attained by differential grinding and air classification because of the difference in hardness of the two minerals) but the separation is not sharp. Froth flotation of pyrophyllite from Quartz has never been attempted commercially, but if the demand for high-grade material is sufficient, it would seem that this process offers the most premise of being economically feasible.

Jan 1, 1950

By Mark H. Hashiguchi

Examination of tensile bar surfaces shortly after destructive testing was conducted to search for clues that would aid in optimization of mechanical properties, especially tensile strength, yield strength and elongation to fracture. Cu-Ni-Si-Cr alloy bars in the as-cast, forged, rolled and extruded conditions were examined. Low ductility bars (<4% Elongation) showed dramatically different features than the fracture surfaces of high strength - high ductility bars (7 to 10% Elongation). Analysis of the fracture surfaces at 15X to 2000X and use of Energy-Dispersive X-Ray Spectroscopy (EDS) identified Ni-Si and Ni-Si-Cr precipitates of varying sizes and morphologies. Thermo-mechanical processing techniques to control the size and distribution of these precipitates show promise in improving the properties and performance of this alloy system and appear to correlate with improvements in the fracture surface morphology.

Jan 1, 2008

By C. Laird, C. E. Feltner

IN previous workif2 we have shown that the steady state cyclic stress response of pure copper tested in the low cycle fatigue range was determined only by the plastic strain amplitude and the test temperature. hus, copper, at any given temperature, has a unique cyclic stress-strain curve independent of prior history. Cu-7.5 wt pct Al, however, showed a stress response for a given plastic strain amplitude and temperature which depended sensitively on prior history. From this work we predicted that all wavy slip mode materials, typified by copper, would have a unique cyclic stress-strain curve; whereas all planar slip mode materials, typified by Cu-7.5 pct Al, would not. This prediction has now been tested for a number of materials of widely varying crystal structure and slip character. Wavy slip mode materials studied include: Fe. Al, Cd, disordered FeCo-V, and Cu-3 pct Co (quenched and aged). Planar slip mode materials investigated include: Fe-3 pct Si, ordered FeCo-V, disordered Ni3Mn, ordered Ni3Mn, and Zn. The treatment and properties of these materials are listed in Table I. Cyclic stress-strain curves were determined by controlled plastic strain tests (see Ref. 1 for details) at room temperature for all materials in both the initially annealed and cold worked conditions. The results obtained for iron and Fe-3 pct Si are typical of wavy and planar slip mode materials, respectively. The cyclic stress-strain curves for these materials are shown in Fig. 1 and it can be seen that iron has a unique cyclic stress strain curve while Fe-3 pct Si does not. Aluminum, Cu-3 pct Co, and disordered FeCo-V showed a behavior like that for iron, while Ni3Mn in both the disordered and ordered condition behaved in the same manner as Fe-3 pct Si. These results therefore support the general conclusion drawn in Refs. 1 and 2 that. for wavy slip mode materials, a cyclic mechanical equation of slate it =t.(hcp, i. T) is approximated in which the satura-

Jan 1, 1970

By S. M. Purdy

Under certain conditions of hot rolling and air cooling from the hot-rolling temperature, bars of a high carbon (0.40 pct C) chrome-nickel austen-itic alloy were found to show magnetism even though no ferrite or martensite could be detected by microscopic or X-yay methods. The appearance of magnetism in such alloys may come from chromium impoverishment of the austenite grains near the precipitated carbide particles. SPORADICALLY, hot-rolled bars of Silchrome 10, an exhaust valve steel, have been found to be magnetic. Because of the analysis of the alloy—0.40 pct C, 18 pct Cr, 8 pct Ni, 3 pct Si —magnetism is unexpected. Preliminary investigation showed neither martensite nor ferrite to be present; only austenite and Cr23C6. Since a literature search was fruitless, a brief study was made of the appearance of magnetism in this alloy. The only basic difference between the two heats is the nitrogen content. Permeability was measured using a Severn magnetic gauge. This instrument consists of a magnet mounted on a counterbalanced arm. A set of calibrated plugs is placed in contact with one pole of the magnet. The specimen is placed close to the other pole of the magnet. If the specimen pulls the magnet away from the plug, it has a permeability greater than that marked on the plug. This technique is swift and reproducible. Previous experience has shown that the permeabilities obtained corresponded to those obtained on a permeater with a field strength of 100 oe. Specimens from both heats were annealed at temperatures between 1700 and 2300°F. One set of specimens was water cooled and another furnace cooled. All the water-quenched specimens were non-magnetic; the furnace cooled ones were magnetic as shown in Table I with no difference being observed between the two heats. Microstructural examination of the specimens showed the expected increase in carbon solubility with increasing temperature. Carbide solution was complete at 2200°F. The specimens heated to 1900°F or below showed some carbide precipitation from the hot-rolled structure. A furnace cooled specimen from a given temperature showed less carbide out of solution than the water-quenched specimen from the next temperature below; e.g., the specimen furnace cooled from 2100°F showed less carbide out of solution than the water-quenched specimen from 2000" F. These studies indicated that the appearance of magnetism was not related to the quantity of carbon in or out of solution and it was related to precipitation at temperatures below 1700" F. A set of samples annealed and water-quenched from 2100° F was aged for 4 hr at temperatures between 1000" and 1600°F; all were non-magnetic. A second set of samples, similarly annealed, was aged 1 to 24 hr at 1200°F with the results shown in Table II. None of the latter set of specimens showed magnetism until they had been aged about 8 hr. Magnetism was quite strong after aging 24 hr. X-ray diffraction studies on several of the magnetic specimens showed that the austenite had a lattice parameter of 3.58A and that the carbide was Cr23C6. Several of these samples were electrolytically digested in 10 pct HCl in ethanol, with a current density of 0.1 amp per sq cm. None of the particles in the residue were magnetic. Accidentally, one cell was run at 1 amp per sq cm; e.g., magnetic particles were found in this residue. After careful separation, the magnetic particles were mounted on a quartz fiber and their diffraction pattern determined using a 5.73-in. Debye-Sherrer camera with CrK radiation. These particles showed a fcc structure with a lattice parameter of 3.57A. Prolonged exposure, up to 16 hr, produced no other lines on the film. The following facts seemed to be established at this time: 1) Austenite was the magnetic phase. 2) Neither ferrite nor martensite could be detected. 3) Magnetization could be produced by aging at 1200°F. One explanation of these data is that the carbide precipitation impoverishes the region immediately around the carbide particle of carbon and chromium and increases the proportion of nickel. All of these serve to increase the Curie temperature of the region around the carbide particle. If the composition change is enough, the Curie temperature will rise above room temperature. If the volume of the affected region is great enough, the magnetism will become detectable. At low aging temperatures, composition changes are great enough but the overall volume of impoverishment is quite small

Jan 1, 1962

By John A. Teeter

"A SHORT WHILE AGO I enquired about The Mining Society of Nova Scotia. In all honesty I was apprehensive about addressing such a body if it was highly geared to the technical aspects of discovering and obtaining mineral resources. I was told that this would not be the case. Rather, there would likely be in attendance a broad cross section of people from business, industry and government and from across Canada and the U.S.A. Thus there would be an interest in a free-wheeling discussion of the prospects for industrial development in Cape Breton. Accordingly - being one who hates to miss an opportunity - I intend to exploit the invitation of your executive by being, over the next short while, frankly promotional. I would like to talk about what I consider to be some of the most important attributes of Cape Breton for industrial development and identify some of those prospects. Secondly, I will quickly review some of the things the Cape Breton Development Corporation is doing these days to stimulate some of that industrial development."

Jan 1, 1972

By C. R. St. John, R. W. Lindsay, Charles R. Austin

MANY of the factors influencing the creep behavior of ferrous alloys have been investigated and reported upon in the literature, including such variables as grain size, steelmaking practice, nature and stability of the microstructure, and the effect of alloying elements in steels. However, with respect to the latter, the microstructures involved are usually heterogeneous and as a result the effect of the addition is related to its effects on the various phases present in the microstructure. In the instances where this structure consists of ferrite and carbide, the behavior of the alloy addition will be related to its action in strengthening ferrite and in opposing temperature softening of ferrite as well as coalescence of carbide. The present paper is the third in a series comprising a comprehensive review of investigations on the properties of iron binary alloys. 1.2 Its purpose is to describe the results of isolating one microstructural phase, namely ferrite, and studying its creep characteristics in both the unalloyed and alloyed conditions. This should aid in establishing to a large degree the importance of ferrite in the creep behavior of steels consisting of the previously mentioned ferrite-carbide aggregate. REVIEW OF PREVIOUS WORK In view of the fact that the present investigation deals only with the effects of silicon, manganese, chromium, molybdenum, nickel, and cobalt, and to a certain extent with the effects of carbon, the review of previous literature will be confined to these elements. Practically no references were encountered dealing with the influence of these elements on the creep characteristics of the isolated phase. However, various contributions have dealt with the creep behavior of low-carbon steels alloyed with the elements under consideration. A particularly concise review in this respect is given by Bullens (Battelle)3 and much of this material has been drawn upon. The definite improvement in creep resistance and high-temperature strength conferred by molybdenum is well known. Published suggestions by the A.S.M.E.4 permit of an increase of some 2000 to 5000 lb. per sq. in. in permissible design loads over a temperature range from 650° to 1000°F. as a consequence of additions of 0.40 to o.60 per cent of this element in carbon steels of the order of o.25 to o.35 per cent carbon content. Babcock and Wilcox Tube Co.5 has published data showing the pronounced increase in stress necessary to cause one per cent creep per 10,000 hr. when additions of 0.5 or 1 per cent molybdenum are made to a plain carbon steel. These data apply to temperatures over a range from 800° to 1000°F.

Jan 1, 1945

By Dogan Paktunc, Larry J. Hulbert, Robert C. Carne, D. Conrad Grégoire

Abstract -A thin layer of stratiform Ni-Zn-PGE sulfide mineralization of sedimentary-diagenetic origin was deposited during the Middle to Upper Devonian in the euxinic "Nick basin". The mineralized unit (2:3 cm thick), which seems to have been developed over the entire sedimentary basin of >80 km2, consists of pyrite, vaesite (NiSi), and sphalerite. The average grade of the mineralization is about 5.3% Ni, 0.73% Zn, ?770 ppb (PGE+Au), and up to 61 ppm Re. Anomalous Se, As, Mo, P, Ba and U are present. A minimum of 0.90 x 106 tonnes of Ni were deposited in the basin (based on a bed thickness of 3 cm) during the Devonian. The unique metal association, extensive lateral distribution, persistent metal grade, mineralogical makeup, and stratigraphic control demonstrate that this is a new deposit type and a new geological environment for Ni and PGE +Au. The sulfide layer occurs at the base of a Phosphatic Chert Member which is underlain by a distinctive marker unit consisting of concretionary limestone structures. The limestone spheroids may represent a vent-specific carbonate facies developed adjacent to faults that emanated nutrient­ rich hydrothermal discharges just prior to the main mineralizing event. The suite of elements associated with the Nick mineralization suggests that the ore-forming metals were originally bound to organic matter derived from decaying marine organisms. Discharge of hot brines bearing organic­ matter-bound metals took place along numerous conduits within basin faults that are now manifest as bitumen veins. Our syndiagenetic model proposes that these fluids were discharged laterally from the conduits into the unconsolidated bottom sediment (ooze). The introduction of this metalliferous fluid, rich in organic matter, stimulated biological activity and bacterial reduction of its contained S04 to sulfide. Hot, dense, laterally migrating hydrothermal fluid precipitated thin sulfide-rich 1arninae within bottom sediment. Published thermodynamic studies suggest that the diagnostic vaesite­ pyrite assemblage crystallized at approximately 138°C. The ?34:S values range from -14.7 o/oo to-10.0 o/oo and are up to 34 o/00 lighter than locally surrounding sulfides and age-equivalent mineralized strata elsewhere in the Selwyn Basin. The ?13:C values of calcite in the footwall of the mineralized unit ( -12 o/00 to -6 o/00) are isotopically much lighter than regional values. The lighter isotopic character is attributed to the hydrothermal discharge of fluids enriched in organic compounds. Although geochemical profiles of the lower Earn Group sediments that host the Nick mineralization reveal that these black shales are not distinctive, the unusual Ni, Zn, PGE, U, Ba, and P elemental associations and their anomalous concentrations in stream sediments can be used to explore for this deposit type.

Jan 1, 1992

By Bertil I. Pålsson

The most common REE containing mineral that is worked today is bastnäsite. It means that mineral processes are adapted to it and that the metallurgical separation techniques for winning of individual REE are adapted to bastnäsite concentrates. For all other deposit types, suitable mineral processing methods and separation technologies need to be adapted and/or developed. Preliminary mineralogical analyses indicate that slightly less than half of the REE in the tailings dumps at LKAB/Kiruna are associated to apatite. The rest is in the minerals monazite (maybe associated to apatite) and allanite. At least allanite is probably not floatable with reagents commonly used for apatite. Mass and element distributions for the tailings sand reveal that very little apatite is present above 300 µm, and that approx. 30 % is below 20 µm. REE does not follow P2O5 completely and are also present in coarser fractions. Flotation results show that the best condition for both apatite and REE winning is pH 9, high collector addition and low dosage of water glass. Under these conditions, the lab-scale flotation gives an apatite concentrate with at least 30 % P2O5 at 70 % recovery. REE follows apatite in the cleaner steps but only partly. Its recovery is approx. half compared with apatite. The reason for the low REE recovery is likely to be that REE to a large extent is trapped in non-winnable minerals, especially allanite. The REE grades in the concentrate are expected to be in the range 3000 ? 4500 g/ton. Keywords: flotation, REE, apatite, monazite, allanite

Sep 1, 2012

By A. C. Spencer, H. F. Bain, E. C. Harder, Sidney Paige, C. M. Weld, W. Lindgren

At a meeting of the New York Section, on May 23, 1918, the sole subject of discussion was the nature and occurrence of iron ores in certain parts of the world." Owing to the importance of this subject, it has been deemed advisable to publish the remarks made at that meeting in the form of a paper, for presentation at the Milwaukee Meeting. The remarks related to the following districts: Page Brazil. By E. C. Harder................................. 116 Scandinavia. By Waldemar Lindgren..................... 120 Cuba. By C. M. Weld.................................. 124 Southern Europe. By A. C. Spencer...................... 130 China. By H. Foster Bain............................... 132 Alsace-Lorraine. By Sidney Paige......................... 135 Brazil BY E. C. HARDER† During the years immediately preceding the war, the iron ores of Brazil were attracting the attention of iron operators both in Europe and in the United States. This was due to the large quantities of practically undeveloped ore available, and to its great purity. It is reasonably safe to state that had capital not been diverted from the exploitation of these deposits to war purposes, Brazilian iron ores would probably now be offered in European and American markets. It is certain that after the war these ores will play a prominent part in the economic reconstruction of Europe and perhaps in the development of America. The Brazilian iron-ore field ranks among the six great iron-ore districts of the world, the others being: (1) The Lake Superior district of the United States; (2) the Lorraine ore field of northern France and southern Germany; (3) the magnetic deposits of northern Sweden; (4) the ore fields of Oriente, Cuba; and (5) the Wabana ores of Newfoundland. It is doubtless the greatest known undeveloped iron-ore district in the world. The Brazilian iron ores are situated in the State of Minas Geraes, the center of the district being located about 250 miles in a direct line west of

Jan 1, 1920

By S. Veeramasuneni, Qingxia Liu, Susan Dichter

Gypsum (CaSO4-2H2O) is an abundant and naturally occurring mineral. Under elevated temperatures (250 to 300°F) gypsum loses its crystalline water and is converted to hemihydrate (CaSO4 -0.5H2O). The hemihydrate form is also called plaster that is widely used in wall- board, joint compound, and many other industrial applications. At temperatures higher than 450°F (up to 1,200°F), gypsum loses all crystalline water and is converted to anhydrite form (CaSO4). The loss of crystalline water at elevated temperatures is an endothermic reaction. This property makes gypsum an attractive filler and fire retardant in certain thermosetting plastics. The applications of gypsum in plastics, food, pharmaceutical, and paper coatings will be reviewed in this paper. The future of synthetic gypsum, a by product of various industrial processes, will also be discussed.

Jan 1, 2003

By Robert P. Koenig

FOR the first time other than on occasion of war the people of the United States are experiencing full-scale participation in world affairs. Public concern has seldom been so involved with conditions and events beyond our own continental limits. Our interest is not wholly of recent origin. Over the years the activity of the United States as a world power and an important trading nation brought about the widening of our political interests and the progressive interrelation of our economy with that of the rest of the world. Some may see in our present phase of world-wide activity the natural consequence of our continued growth. Such observers must also be aware that within recent years our importance in world affairs has been considerably increased. For within the space of an extremely short period events have occurred that have literally jet-propelled the United States into the role of a leading participant in the conduct of world affairs. Little of the choice of this role was left to us. The decline of power in western Europe, the ascendancy between the Elbe and the Pacific shore of an obviously antagonistic force, our earnest endeavor to secure international control of atomic energy, the necessity of providing relief and rehabilitation to war-ravaged areas, and the police work that must be done in occupied territories are problems which have risen in great measure without our help-but they cannot be solved without it.

Jan 1, 1948

This paper presents a theoretical investigation on the ionic equilibrium of Fe(III)?Ni(II)?H2SO4?H2O system. A non-ideal speciation model is developed to calculate the concentration distribution of iron and nickel species in a mixed ferric and nickel sulphate aqueous solution over the pH range from 0 to 4 and temperature from 25 to 100°C. A series of speciation diagrams for iron and nickel species is plotted with the effects of ionic strength and temperature on the equilibrium constants being taken into account. The ionic strength-dependent equilibrium constant is treated through a semi-empirical Vasil&apos;eV equation, which is based on an extended Debye?Hückel theory. A Helgeson model is applied to extrapolate the equilibrium constant to elevated temperature. The ionic equilibrium reactions are described by a group of numerical equations containing the temperature and ionic strength-dependent equilibrium constants, which are solved by the Newton-Raphson method. The speciation model is also applied to estimate the hydrogen ion activities and corresponding pH values. The calculated pH values are in agreement with the experimentally measured pH, and are compared to literature data and pH values produced by the Visual MINTEQ® program (a computer code for the calculation of chemical equilibrium in natural aqueous system). This investigation provides a deep insight into the ionic equilibrium behavior of a mixed metal sulphate aqueous system which commonly occurs in hydrometallurgical processing. Keywords: speciation, chemical modelling, thermodynamics, iron, nickel

Sep 1, 2012

By H. A. D. Kirsten

Written contribution by L.J. Besaanst I am a Mechanical Engineering Technician (T3), and wish to further my education to at least NHD (T4) level. I read your paper in the Journal of The South African Institute of Mining and Metallurgy with great interest, and must compliment you on its brilliance. However, there are some questions I should like to ask, and certain points I should like to highlight. I should appreciate your comments. Written contribution by J.F. Curtis The comprehensive and finely detailed survey of, and proposals for, engineering education in South Africa reflects the author&apos;s wide experience in the needs for, and the provision of, such education. This paper wil make a major contribution to the enhancement of the profession of engineering and the improvement in quality of engineering activities in South Africa. Contribution by G.W. Annandalet I have studied your paper in some detail, and am of the opinion that it makes an important contribution to the topic of the development of technological manpower, which is currently being debated in South Africa at al levels. Debate on this topic has risen above the level of academic discussion; it has been discussed by the Economic Advisory Council of the President, and is being considered at Ministerial level. Author&apos;s reply to L.J. Besaans Thank you for your contribution and complimentary remarks. As you have pointed out, there are certainly many aspects that will have to be addressed in the resolution of the crisis in engineering education. I trust that the following comments satisfactorily answer the queries you have raised. Author&apos;s General Comments Since publication of the paper, attention has become focused on the provision of employment opportunities an aspect not dealt with specifically in the paper. The following comments serve to indicate some of the directions in which job opportunities will have to be developed in the numbers that will be required.

Jan 1, 1991

By I. Ciabatti

Inorganic salts of hexavalent iron (ferrate (VI)) are versatile reagents for water and industrial effluent treatment because of the strong oxidising effect of the ferrate ion (FeO42-) and the well-known coagulation properties of the resulting ferric ion. Among other applications, ferrate can effectively remove arsenic, cyanide and phenols from industrial effluents. Furthermore, ferrate salts can be prepared from ferrous sulphate, a common byproduct of the steel and titanium industries, and possibly from other iron wastes. Notwithstanding their many potential advantages, the industrial-scale application of ferrate salts, such as potassium ferrate (K2FeO4), for effluent treatment has been hindered by the difficulties inherent in their synthesis and stabilisation. Within a project co-funded by the European Commission, the large-scale synthesis of stabilised potassium ferrate was realised through a new synthesis process, and different applications of the resulting ferrate to effluent and wastewater treatment are under investigation. This paper reports the results of the application of stabilised potassium ferrate for the purification of textile effluents. Laboratory and pilot-scale tests were carried out and the performance of the ferrate was compared to that of chemicals currently used in wastewater treatment. According to these experiments, potassium ferrate is a promising reagent for an effective treatment of textile and other industrial effluents.

Jan 1, 2006

By Wilhelm Wendt

About five years ago we showed that it is possible to use the spectral in- formation in the light emitted by the off-gas flame of a PS converter for on-line production control. Very recently measurements have been performed using improved optical equipment and data evaluation software, resulting in both improved accuracy and the establishment of new optical process parameters. Using the optical signals the slag heats could be stopped at a predetermined Cu content of the white metal with an accuracy of +0.2% Cu m the range 74-78% Cu. A good correlation was found between the slag composition and optical data, providing a possibility for on-line monitoring of the SiO2 content of the slag. The measurements indicate the possibility of predicting the optimum end-point of the copper-making stage and having real time information on the impurity removal. Factors influencing the optical parameters, such as blowrate, Pb content, temperature etc. will be discussed.

Jan 1, 1993

By Erik Westman, Enji Sun, Xu Ma, Ben Fahrman

"Shale gas has become an increasingly important clean energy, which has been explored worldwide in recent decades. Supercritical CO2 acts as fracturing fluid for shale gas production. The safety monitoring is essential to prevent any kinds of leakage from the reservoir as the supercritical CO2 physically stored hundred kilometres underground. Seismic tomography is an imaging technique that uses induced seismic waves to create three dimensional images of the subsurface. It is an effective monitoring method to evaluate the caprock integrity in the carbon dioxide sequestration storage (CCS). In this experimental research, a simulated uniaxial compressive load is applied on a granite sample to analyze the stress redistribution for long-term in-situ caprock integrity during CO2 injection. The induced seismic waves are recorded and seismic events are traced based on the Geiger algorithm. The frequency of seismic events correlates with the caprock failure evolution. The acquired seismic data is divided into four regimes based on the frequency of seismic events and the failure process to examine the failure evolution. Furthermore, the travel time and distance is plotted to analyze the variation of velocity. Finally, the double difference tomography (TomoDD) algorithm using arrival time is adopted to recalculate the locations of seismic events and velocity structure in each regime. The results indicate that the passive seismic system can map the caprock stress distribution and allow for imaging of the caprock integrity. TomoDD exhibits sound improvements to relocate seismic events both in relative and absolute locations as well as to characterize the local velocity structure. The study further reveals that seismic monitoring along with TomoDD could evaluate the caprock failure accurately in the CCS.Introduction To reduce the CO2 concentration in the atmosphere, CO2 capture and sequestration (CCS) has been suggested to as a means of continuing to use fossil fuel resources while offsetting their negative environmental impacts (Eiken et al 2011). A positive CCS project should retain 99% of the injected supercritical CO2 (pressure is greater than 7.38 MPa and temperature is above 31.04? and a density is of about 700 kg/m3) over at least 100 years (Davidson et al 2005). As large quantities of supercritical carbon dioxide are being injected into full scale storage projects, caprock stress is redistributing and the leakage could occur anywhere over a wide storage area (Hou et al 2012). Acoustic waves are emitted from the caprock, as it fractures due to the CO2 injection, which can be detected by passive seismic sensors (Shitashima et al 2013). Tomography techniques are advantageous for imaging the integrity of the caprock in the CCS projects. Velocity tomography uses waves to model entities based on the arrival time of waves (Westman et al 2001, Westman 2004, Luxbacher et al 2008). Seismic tomography is a data inference technique that exploits information contained in seismic records to constrain 2D or 3D models of the Earth's interior. It generally requires the solution of a large inverse problem to obtain a heterogeneous seismic model that is consistent with field observations (Kudryavtsev et al 2012)."

Jan 1, 2017