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A recently discovered high temperature (22G-2800°C) reaction between glycerol and the oxides and hydrous oxides of iron produces a green, well-crystalline complex glycerato-iron, whereas hydrous nickel oxides an) reduced by the glycerol to metallic nickel. When nickel isomorphously substitutes for iron within the goethite lattice this high temperature glyceration allows a separation of the two metals whereby the nickel can be extracted by solution techniques.

Jan 1, 1971

By Pease JD, Munro PD

The heavy medium cyclone plant for the preconcentration of silver-lead-zinc ore prior to grinding and flotation was commissioned in August 1982. This paper details the measures taken to get the plant up to design performance which involved modifications to the medium densifying and slimes clarifying sections. Operating experiences to date are described with emphasis on the low medium consumption recorded and severe wear on process equipment.

Jan 1, 1984

It is possible from simple gas behavioral theories to develop more complex relationships which allow prediction of transport phenomena such as diffusivity and viscosity of gas mixtures. Such physical data can be used in engineering calculations for both bulk gas movement and gaseous chemical species movement. Both of these are important in the solution of mines ventilation systems. There are specific limits of flammibili!'y of some common mines gases.

Jan 1, 1983

The results of the washing of coal are often presented by using Partition Curves. By analogy, it is possible to express the results of screening by using similar partition curves. As in the coal washing processes, this method determines the accuracy of screening and is also suitable for different separations depending on the difference in size distribu- tion. This method compares the effectiveness of two screening operations and forecasts the performances.

Jan 1, 1984

Gold Fields Ghana Ltd (GF Ghana) currently operates an underground mine at Tarkwa, in south--west Ghana. The mine was operated by Tarkwa Goldfields Limited, a wholly owned subsidiary of the State Gold Mining Corporation of Ghana (SGMC). The mine was making operating losses and in a poor state of repair. Tarkwa Goldfields retrenched all the staff and GF Ghana assumed management responsibility for its own account on I July 1993.

Jan 1, 1997

By Blake W

Based on preliminary computer model simulations and stability analyses, both longi- tudinal and transverse, large dimension, cut- and-fill rooms were designed for the parallel dipping ore layers at Kamoto mine. Full scale testing of the designed rooms showed that the rooms are stable and that the rock behavior is predictable. Ordinary waste rock was selected as the filling material because the fill was found to carry little load.

Jan 1, 1973

By Sauer P

The features of Banana screens have been known for some considerable time and recently considerable interest has been generated in the performance of these units. This paper reviews screening principles on Banana and conventional units and demonstrates the capacity and effic- iency of these units. Furthermore, the behaviour of modern Banana screens and modem screens in general, are examined with respect to life, vibration isolation, noise emission and maintenance requirements.

Jan 1, 1978

The first thing to be aware of is that the warming effect of carbon dioxide is strongly logarithmic. Of the 3¦ that carbon dioxide contributes to the greenhouse effect, the first 20 ppm has a greater effect than the following 400 ppm. By the time we get to the current level of 384 ppm, each 100 ppm increment will produce only about 0.1¦ of warming. With atmospheric carbon dioxide rising at about 2 ppm per annum, temperature will rise at 0.1¦ every 50 years for the next couple of hundred years before the effect becomes minuscule. The warming of the 20th century, as the Earth came out of the Little Ice Age, was a consequence of short, high-amplitude solar cycles. A number of solar physicists have predicted that the next solar cycle, Solar Cycle 24, will be quite weak. Based on the correlation between solar activity and the EarthÆs climate, a temperature decline of 2¦C is predicted for the mid-latitude regions over the coming decade, equating to the experience of the Dalton Minimum. Anthropogenic warming due to carbon dioxide will not ameliorate this temperature decline. Increased atmospheric carbon dioxide is wholly beneficial due to itÆs fertilisation effect. Efforts to inhibit Australian carbon dioxide emissions are exactly wrong in science.

Jan 1, 2009

By See J. B

The zinc-nickel alloy process, TECHNIGALVA, was developed for the control of the thicknesses of zinc -coatings on reactive silicon-killed steels. These are steels containing between 0.04 and 0.15 per cent silicon which have become more common in recent years as more steel is produced by continuous casting. The introduction to this paper will review the current status of this process in Europe, North America and Australasia. It is well known that the presence of silicon at certain levels in steel can cause sufficient growth of intermetallic phases during galvanising to form a grey coating of excessive thickness. This type of coating is undesirable because it is brittle and has poor adhesion to the steel base. Since the early-1980s a widely accepted practice for suppressing the reactivity of steels containing silicon during general galvanising has been the addition of approximately 0.1 mass per cent nickel to the galvanising bath ie the TECHNIGALVA process. The paper will also discuss metallurgical aspects of the use of nickel in galvanising such as the mechanisms by which nickel suppresses reactivity, the structure and composition of the ternary Zn-Fe-Ni drosses formed when using nickel and the use of nickel in the galvanising bath at a level of about 500 ppm to give thinner, smoother and brighter coatings on steel.

Jan 1, 1993

By P G. Fuller

The Woodlawn Mine near Canberra faced the challenge of poor ground conditions from the commencement of underground operations 1987. Talcose shears bounded the dense massive sulphides on both the hangingwall and footwall side of the orebody. In another area the talc existed not only on the edges of the orebody but through out it as well. The country rock was relatively weak shales compounded by a low stress environment that allowed the wall rocks to fall apart quite easily. The challenge for the operators was to overcome the poor ground conditions. This was done by attacking the problem from three directions:technology, how technology is applied, human relations and leadership by all levels of the Management team, and by ensuring that these processes meshed together well.Woodlawn in it early days as an underground mine enlisted the assistance of BFP (Formerly Barrett Fuller and Partners) as a second set of eyes to assist with the assessment of the ground control procedures. The results are discussed in this paper. The progression to this end result included:non-contract payment systems; ground control training for the full range of mining personnel; the development and enhancement of cable bolting and shotcreting equipment; the development of Practical Standard Work Procedures by mine operators; and innovative use of shotcrete and cables bolts to control extremely poor ground conditions.

Jan 1, 1998

I propose to speak today about our mineral heritage. In common usage "heritage" refers to the past. It means the discoveries, the developments, the mines and the processing plants, the benefits, the consequences, and the human experiences flowing from these. The history of the industry, inseparable from the history of the countries in which The Institute operates, is a rich background of which we can all be proud.But there is also a much wider meaning to mineral heritage. Our past has left us with the ab\lity to create and operate world scale enterprises generating wealth for the community, the ability to offer satisfying and challenging careers in a wide range of skills to our young people, and the willingness to follow adventurous and challenging vocations in remote areas, away from the big cities, at a time when the mentality of many is to get the most for the least effort and at the least inconvenience to themselves. The industry continues to be the repository of the pioneer spirit and a vital contributor to improving the life of the people in our countries.Thus, while our mineral heritage has much to do with the past, an essential part of it is how we use this rich past to build and shape our future. It is in this broader context that I am speaking today.

Jan 1, 1990

By Sturgul J. R

A major electricity generating authority have a proposal to construct a Power Station. An understanding of the operation of the bunker system is of importance to the designers and a computer simulation model of the operation was constructed. The computer language used was GPSS/PC which is a recent form of the language designed for the per- sonal computer. The model simulated trains arriving at the power sta- tion and unloading onto conveyors which carry coal to the power station bunker. Coal was drawn from the bunker at a specified feed rate to the power station. Numerous restrictions were placed on the model, if the bunker level got too high dozers would pull coal out of the bunker onto the stockpile, and if the level got too low the dozers would push coal back into the bunker. The conveyors and dozers were unavailable due to breakdown'at various times and trains would arrive randomly about a mean interarrival time. The system was simulated for 30 years of oper- ation and the model used a basic time unit of 30 minutes so that the system was updated 525,600 times during the simulation. The results of the simu- lation gave the designers a greater understanding of the critical factors in the operation, which may now be engineered to minimise adverse Effects.

Jan 1, 1988

By D Hodson

Current classification of resources is entirely a subjective task. The various international reporting codes (such as the JORC Code) provide Competent Persons and practitioners with little specific guidance on the standard of work and levels of uncertainty required to classify resources into Measured, Indicated and Inferred. Furthermore, little guidance is given in the conversion of Resources to Reserves and the potential impacts on classification of uncertainties in the modifying factors. Working back from the intended use of the resource estimates, and in understanding the tolerance for uncertainty by the end user of such estimates, insights into the objective and requirements of classification can be determined. Following this approach a comprehensive set of (quantitative where possible) guidelines have been determined that will ensure resources meet the desired objective of each classification, and are consistent and comparable. The guidelines look at what is required for each step in the resource estimation process in order to ensure the final resource estimate meets the desired level of confidence. This approach provides a transparent, comprehensive, justifiable and largely objective method of classification. The implication of introducing such a guideline or approach is to highlight areas of a resource estimation that do not meet the requirements (ie drive the uncertainty beyond the objective) and then focus in on the risks that may flow on from that particular uncertainty, to mitigate or attempt to control those risks.

Jan 1, 2006

By De Cuyper J

Laboratory testwork has been performed on ancient residues from the cyanidation of a previously roasted gold-containing pyrite and arsenopyrite ore. By grinding to 95 per cent minus 60 microns, and after a strong aeration conditioning of the pulp, a gold recovery of approximately 67 per cent was obtained by cyanidation. This recovery was brought up to 80 per cent by leaching with thiourea, after a preleaching step with sulphuric acid under severe conditions of acidity and temperature. To avoid excessive capital costs bound to such processes, it was decided to investigate the possibility of applying flotation after grinding at a size similar or finer than the one used for the leaching tests. The method turned out to give interesting results because of the natural flotability observed at pH values lower than two for particles rich in gold present in the residue. After two cleaning steps, a final concentrate, representing around one weight per cent of the feed, was obtained with an approximate gold content of 350 g/t, representing a batch recovery of gold of about 50 per cent. Apart from sulphuric acid, whose addition was very high (flotation slurries at 25 g/l H2SO4), other reagents were not found necessary. Additional flotation tests were carried out to examine whether the recycling of the cleaner tails was justified but the gain observed appeared insufficient.

Jan 1, 1993

By J Herbertson

æZero waste steel making productionÆ has already been the subject of several studies and also the successful result of some companies. Regarding waste and by-products, slags are the largest in terms of weight, although among the least hazardous. All steelmakers around the world are presently looking into profitable solutions, according to their local conditions: environment constraints, available markets, and mode of operation. Today the major technical methods of slag value capture include different levels of magnetic separation and screening to remove entrained steel, for production of aggregate in civil works. A survey of different retrieval processes shows that pyrometallurgical processing of steelmaking slags will increase the recovery ratio of iron and other metals. In the process, the remaining part of the material, a mixture of metallic oxides, can be easily transformed into hydraulic binder such as cement. Can steelmakers consider the slag as a co-product, and not only a waste or by-product? The ability of pyrometallurgical processes to treat other wastes and by-products generated in the steelplant is an opportunity for the steelmakers to reach the æzero waste productionÆ status. A technical survey of the experiences and possible solutions of pyrometallurgical processing is presented as well as technical descriptions of technological, economical and profitability analysis in relation with foreseeable markets.

Jan 1, 2002

By Haartti J

Generally when equipment is chosen for solving a dewatering problem, the equipment is based on one of following physical methods: gravity (sedimentation, screens), vacuum (vacuum drum and disc filters, belt filters), pressure (filter presses, hyperbaric filters) and centrifugal forces (centrifuges). The choice of method and type of equipment depends, among other things, on the requirements on the maximum water content allowed in the filter cake and on the particle size distribution and the concentration of solids in the material to be dewatered. All the above-mentioned equipment has its benefits and drawbacks. The conventional vacuum filters of drum or disc type are of a simple construction with few parts to be replaced, but these filters produce a filter cake with a fairly high moisture content, and a dryer is required for additional drying. In most cases the use of pressure makes it possible to produce filter cakes with the desired moisture content but the equipment is of complicated construction, leading to high maintenance costs . In addition to this the consumption of compressed air is high. The capillary filtration to be described in this article is a dewatering method which combines the benefits of both the conventional vacuum disc filter and the filter press. The capillary filter produces low cake moistures with a machine of very simple construction similar to that of the vacuum disc filter.

Jan 1, 1993

n One of the most interesting and economically important developments which has .`taken place- in the Kalgoorlie Field over the past twenty .years is the proved penetration of ore into - caicò schist. which:has been established on the North Kalgurli Mine. 'This is quite extensive, both. laterally and ' in -depth, and has occasioned-,'" ccasioned ' " some madification.of geological thought In the search for additional ore sources:. .Ore has been mined in calc schist almost since the' first major: gold::discoveries-were made,. and the principal 'features of the various types of depos:itl are well covered in the literature ' of the field. ' However, occurrences in caic schist have not-been characterised by the same degree of continuity or frequency as the innumerable lode formations in- the more -favourable quartz dolerite, ' and there has been a tendencyAo regard,them as isolated and discontinuous ore bearing structures, occurring only under very special-- conditions. It is not intended-:to describe the whole' range of caic schist ore occurrences in this paper, but only major controlling structures, whose penetration therein has been definitely established, and in which an appreciable .amount.of,_ore.has, been and is still being. found.. . It is considered that -similar stiiictiires: may present a' major objective for future exploratory work in other parts of the field'.

Jan 1, 1964

By F De Beurs, S Davies

With the emphasis on CO2 emission legislation and the increasing price of traditional fossil fuels like coal, oil and gas, the use of alternative fuels is becoming more and more attractive for the industry, particularly for the cement industry. The variety of materials burnt in the kiln is enormous and varies from tyres, to animal meal and other waste material or by-products that would otherwise end up in an incinerator or landfill facility. This wide variety in materials demands thorough analysis to determine what elements are present in the organic matrix. The elements present may have an influence on the process or the quality of the cement. Toxic or environmental unfriendly elements may be incorporated or dissolved in the clinker phases; whereas volatile components may be present in stack emission to the atmosphere. X-ray analysis is already the key to elemental analysis in cement production, and is used here to determine the composition of these alternative fuels. The XRF spectrometer configuration used in this study is designed to overcome the difficulties associated with the analysis of strongly varying light organic matrices containing heavier elements in minor and trace-level quantities. Heavy element specific excitation conditions and three-dimensional polarised optical geometry increased the signal to background ratio and improved detection limits compared to conventional XRF spectrometers.

Jan 1, 2008

The Rotary Kiln at TeKumi was commissioned in February 2002. The process involves burning limestone at 1000 - 11 000¦C to produce a burnt lime (CaO) product. This paper describes the design and installation of a trifoil system to improve the energy efficiency of the kiln. An energy balance showed that 32 per cent of the energy was being lost through the flue gases, compared to 5.8 per cent in shell losses and 2.5 per cent lost as heat in the product. The trifoil proved to be the best way to tap the energy from the flue gases. Drying tests showed that a trifoil improved the drying time of limestone by 37.5 per cent, compared to only 25 per cent for a lifter system. The trifoil system increases the surface area for heat transfer in a Rotary Kiln by 180 per cent. The overal energy efficiency of the Rotary Kiln was improved by 15 per cent, resulting in a 15 per cent increase in production and an 80¦C reduction in flue gas temperature. This has reduced dust build up in the ducting while reducing maintenance costs through a reduced fan speed. The trifoil hub was designed with tooths at the centre to prevent shifting. Each trifoil leg has an anchor block on the down side to prevent downward movement of the trefoil legs.

Jan 1, 2003

ALTHOUGH the development of the various flotation processes during the last 8 years has been so revolutionary, this development has been, until recently, entirely confined to the separation of the gangue from the mixed metalliferous sulphides.The desirability of finding some method of separating the independent sulphides from such a miXture, by means of flotation, has long been recognized. ThIS need was emphasized when the slimes resulting from the grinding of Broken Hill sulphide ores were for the first time successfully dealt with by the Mineral Separation Company's process on the Central mine. This process proved the practicability of separating the sulphides of lead and zinc as a mixed concentrate from the gangue present in slime. Although this was a very notable achievement, the process has not been generally used, owing to the mixed lead and zinc concentrates resulting from the treatment being acceptable neither to the zinc nor the lead smelters.Although the introduction of eucalyptus oil in minute quantities as an emulsifying agent has simplified the work of the subsequent tabling of mixed sulphide concentrates, rendering unnecessary the burning off or removal of the oil, there will always be a considerable quantity of slimy product too fine to settle on the moving surface of the concentrating machines, and therefore requiring other means for its division into lead and zinc concentrates.

Jan 1, 1911