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By Pollmans GJ, Hoberg H, Schneider FU

The Institute of Mineral Processing at Aachen University of Technology has been engaged in fine and ultrafine comminution for several years. Former investigations had been dealing with the mechanical activation with the aim of increasing the solubility of highly resistant oxides such as tantalite and niobite while research on the product of ultrafine powders is of major importance at the moment. Materials of that kind are of increasing interest in the production of extremely resistant ceramics, in the development of new raw materials, in powder metallurgy and in the production of fillers (extender pigments) and pigments. The creation of ultrafine powders is difficult and very expensive. They can be produced by means of condensation or dispersion methods. One important method of dispersion is mechanical comminution. Due to long and intensive research and development all over the world important advances have been achieved but still a great number of questions and problems occur especially in producing materials of submicron and nanometer grain sizes which could be answered or solved only insufficiently up to now. These mentioned difficulties refer especially to: ò the required energy input into the feed material, ò the forming of strong agglomerates and wall stickings, ò the required product qualities, and ò the entire and reliable characterisation of the products. Basic investigation aim to clarify the micro and macro processes of ultrafine grinding and work towards solutions to the difficulties mentioned above. The aim of the Institute's research is the development of a new grinding device for producing ultrafine powders. First results of a laboratory scale mill of that type will be presented in this paper.

Jan 1, 1993

The treatment of nickel ores and concentrates and the subsequent processing to recover separate products of nickel and cobalt is one of the major interests at present in the mining industry. The increasing demand for nickel, and more recently also cobalt, has led to increased exploration for ore sources. Major discoveries have resulted in Canada and Australia. These deposits, as well as others already known, are presently being developed and the process technology tested and evaluated for applicability to the different mineralogical types - mainly sulphide, arsenide and oxide laterites. Concentrates may be treated by either hydro- or pyrometallurgical processes, while the nickel laterites are best suited to hydrometallurgical processing. However, if hydrometallurgy is used, once the ore or concentrate is leached the resultant solutions are then amenable to similar separation technologies for purification and recovery of high purity nickel and cobalt products. Solvent extraction, together with other separation processes such as precipitation, can produce high purity solutions of nickel and cobalt. The final products of these solutions may be nickel and cobalt cathodes, metal powders precipitates or salts, depending on the final process of electrowinning, hydrogen reduction, precipitation, or crystallisation Respectively.

Jan 1, 1996

By Finlayson E, Hilyard D, Francis G

Papua New Guinea's mainland is dominated by a foreland thrust belt, which can be divided into two zones. The "body" zone is floored by Palaeozoic granites and metamorphics of the Fly Platform (Tasman Orogen). Underlying the "tail" zone is Papuan Plateau, rifted from the Tasman Orogen during Coral Sea spreading, and believed to underlie the Papuan Peninsula and Papuan Islands region (D'Entrecasteaux, Woodlark, Misima, Sudest, and Rossel Islands). Thrusting began in the Miocene and continues today in the crust below the "body" zone. The youngest known thrusted rocks in the "tail" zone are Pliocene in age. Recognition of foreland thrusting has major implications for petroleum prospectivity of the Papuan and North New Guinea Basins, mineral exploration prospectivity, and geological terrane identification in PNG.

Jan 1, 1987

By Koh P. T L, Varnas S. R

Fluid flow, heat transfer and combustion in a nickel flash smelter have been investigated by numerical modelling and flow visualisation. The three-dimensional numerical model incorporates turbulent two-phase fluid dynamics, radiative heat transfer and combustion. The main features include the use of the k-E turbulence model, the Lagrangian tracking of particles, radiative heat transfer based on the spherical harmonics method, and chemical reactions. The predicted flow fields are in good agreement with data obtained from a series of flow visualisation experiments on a cold water model. The interaction mechanism between the fluid flow and the solid particles is examined for a range of particle sizes both with and without injected oil in a series of simulations. The heat transfer in the shaft is dominated by combustion and radiation, whereas the ignition of particles is influenced by the particle size and the added oil. Flow and temperature fields for both gas and solid particles are presented as well as the fraction of sulphur removed from the particles.

Jan 1, 1992

By W L. Lane, T R. Yanske

The Doe Run Company and its predecessors have been mining for over 130 years utilising the room and pillar mining method. This method has left approximately 20 per cent of the orebody in the remaining pillars. The original design and planning for the mines did not include extensive pillar extraction. This paper summarises the introduction of the pillar extraction and backfill techniques which have been implemented since 1991. These techniques include the use of low cost fill walls up to 20 m in height and the use of slinger trucks for topping off the fill. In conjunction with these accomplishments, much experience and confidence has been gained in the use of numerical modelling as a method of predicting pillar stability as the mining of pillars progresses. These advances have led to pillar extraction becoming a major portion of the overall production and have added to the mine life of Doe RunÆs six operating mines.

Jan 1, 1998

Host minerals for gold have been of great interest to exploration geologists and metallurgists for a variety of reasons. The depletion of high grade ores in many parts of the world requires that greater attention be given to the study of host min-erals for gold. Some host minerals have been employed in exploration as traces for gold. They are also essential in the design of extraction processes for treating gold ores.This paper reviews the mineralogy of important gold deposits of Papua New Guinea (PNG), Indonesia and New Zealand and focuses attention on the ore minerals and rock-forming minerals that host gold.

Jan 1, 1994

By Sagrabb T

In a company's quest for financing the development of a new mine, it will make calls on stockbroking houses and banks. The choice of the best-fit broker or banker is of great importance, and in the case of the miner, this is a house that has an intimate understanding of the mining industry, particularly one that has a solid staff complement of personnel with operating mine experience at a senior level. The most important document that the company will present to support its financing request will be the Feasibility Study. It cannot be too strongly emphasised that this document must be absolutely comprehensive and cover items including: (a) Geological review; (b) Resources and reserves; (c) Mineability; (d) Mining schedule; (e) Metallurgy; (f) Process plant description; (g) Infrastructure and services; (h) Management and operations; (i) Environmental and social impact; (j) Capital costs; (k) Operating costs; and (1) Financial analysis. The elements listed above represent major topics and require a great deal of expansion in the body of the document. Rothschild Australia Limited assists its client companies by supplying a detailed framework so that they will be in a position give the bank the information it needs to complete its technical `due diligence' study within a mutually agreed time. The client company will advance its position markedly if it uses well-known, reputable consultants to either complete or assist with the various aspects of the Feasibility Study. Such an approach will give the potential financier confidence that the company has taken a professional and unbiased attitude in determining the feasibility of the property in question. Most small- to medium-sized mining companies, both within Australia and overseas, will prefer, or will find it mandatory, to request a project funding package rather than opt for a corporate loan. This is because the company either does not want to tie all of its assets to the performance of one project, or that it is a one or two project company with no other substantial assets and is therefore unable to obtain a corporate loan. Upon receipt of the Feasibility Study, the bank will use the data supplied by the company in its cash flow analysis to build its own financial model. The purpose of this is to examine the timing of

Jan 1, 1994

This paper investigates dry drilling as a feasible alternative to meet current requirements for improvements in mining productivity in an increasingly competitive world.A field test program was conducted in the surface facilities of a hard rock mine in Sudbury, Canada, to investigate the potential use of dry drilling in underground bulk mining as a conceivably faster and more economical method than wet drilling. The test work consisted of the monitoring of advance rates and bit life while a series of 165 mm diameter holes, wet and dry, were drilled with compressed air at both mine (0.69 MPa) and high (1.72 MPa) pressure levels. The results indicate that penetration rates can be increased by approximately 24 per cent by drilling dry with high air pressure and by approximately 27 per cent by drilling dry with mine air as compared with wet drilling under the same conditions. Dry drilling also has the effect of increasing bit life by up to 69 per cent. An economic analysis for typical hard rock mines indicated that drilling productivity and cost savings can be increased by approximately 23 per cent when dry drilling is utilised.The testing program indicates that dry drilling has the potential to become a feasible technique with regard to performance, productivity and costs.

Jan 1, 1991

By Walker K, Burton RC

An outline of the ventilation and refrigeration requirements of deep South African gold mines is presented. This is followed by a brief description of the history of controlled recirculation in mines and the practical and economic benefits such schemes can offer. The potential hazard of a fire in a recirculation system is discussed.The major part of the paper describes the first large-scale field trial of controlled recirculation to be conducted in South Africa. Emphasis is placed on the monitoring system that was used for data acquisition during the trial, and also on a safety system designed to shut off the recirculation fans in the event of a fire.The paper concludes with a review of the latest development work taking place on recirc-ulation safety systems.

Jan 1, 1985

By M H. Randell, J B. Haines

The Honeymoon Uranium Project comprises the Honeymoon Deposit,Goulds Dam Deposit and Yarramba Prospect in the Southern Lake Fromeregion, South Australia. Both the Yarramba Prospect and HoneymoonDeposit (which includes Honeymoon and East Kalkaroo orebodies) arelocated in the Yarramba Palaeovalley. The Goulds Dam Deposit is about75 km north west of Honeymoon, in the Billeroo Palaeovalley. Exploration for sediment-hosted uranium began in the area in the late1960s, culminating in the discovery of Honeymoon and Goulds Dam inthe early 1970s. In 1982, a 25 L/s demonstration plant was built atHoneymoon to confirm suitability for in situ leaching. The project was put on hold in 1983 due to changes in government policy. Southern Cross Resources Australia Pty Ltd acquired the project in mid 1997. Roll-front deposits form from a migrating geochemical cell, anadvancing reduction-oxidation interface between oxygenateduranium-bearing groundwater and its reduced aquifer host. The source of metal is uranium-anomalous granites, which were eroded fromsurrounding ranges. The weathered granites and resultant sediments are stripped of uranium by oxidised groundwaters, to form solutions carrying uranyl carbonate complexes. The solutions percolate down-slope through permeable sand zones until contacting a reduced environment where uranium precipitates. Uranium mineralisation occurs interstitially between and as thin coatings on sand grains, usually in the form of uraninite or coffinite. The palaeovalleys (previously termed palaeochannels) are incised intounderlying Cambrian/Precambrian basement rocks and filled withsemi-consolidated, largely un-cemented, Tertiary sediments of the Eyre Formation. The late Palaeocene to middle Eocene Eyre Formation is the basal unit of the Tertiary succession in the Callabonna Sub-basin of the Lake Eyre Basin. Further to the north, the Lake Eyre Basin overlies the Jurassic-Cretaceous Eromanga Basin, which comprises much of the Great Australian Basin. Eyre Formation sediments are in turn overlain by the late Tertiary Namba Formation and terrestrial Quaternary units. At Honeymoon, the Eyre Formation includes immature, pyritic,carbonaceous sands and gravels interbedded with lignite andkaolinite-illite-montmorillonite clays. It was deposited by braidedstreams during epeirogenic uplift of the Olary Ranges, accompanied bysubsidence of the Lake Eyre Basin. The Eyre Formation comprises aconsistent stratigraphy of interbedded sand and clay units that arecontinuous over the Honeymoon Deposit but with local variationindicating some hydrological connection between aquifers.In the Honeymoon orebody, uranium occurs within coarse-grained,pyritic sands where the basal sand pinches out between overlyingcarbonaceous clay and the southern palaeovalley slope. Its characteristics are typical of the well-developed, planar limb of a roll-front uranium deposit. Zonal changes related to the reduction-oxidation interfaces across the deposit are readily observable. The orebody extends for nearly 1000 m along the valley margin, is 400 m wide at its maximum and averages about 6 m in thickness. The East Kalkaroo orebody also lies near the southern margin of theYarramba Palaeovalley. It extends discontinuously for approximately 3.5 km and averages 200 m width, with significant uranium present in the Middle as well as the Basal Member. The Billeroo Palaeovalley extends northward for 40 km sub-parallel tothe western side of the Benagerie Ridge, is up to 5 km wide and hasgently dipping banks. Eyre Formation within the palaeovalley isconcealed beneath 90 m of Quaternary and Namba cover, isapproximately 40 m thick, and is sub-divided into three upward-finingunits, which are remarkably similar to the Yarramba Palaeovalleysequence.

Jan 1, 2001

The writer had the pleasure of several months' laboratory tests on a metallurgical process for copper ores devised by Mr. W. H. Corbould, Consulting Engineer, North Queensland. Mr. Corbould's research work in this direction commenced somesix years ago, and he eventually succeeded in obtaining a good extraction of copper and a resulting solution practically free from iron and other impurities. The commercial operation of the process was investigated and special machines with novel features were designed. OUTLINE OF THE PROCESS.The process described in detail in the following pages, required for successful application that the ores contain at least the minimum ratio of sulphur to copper, consistent with the production of sulphadising roasting conditions.

Jan 1, 1921

By Brady KT, Pattenden G

A laboratory size solvent extraction apparatus has been constructed, which incorp- orates three stages of countercurrent extraction, followed by two stages of counter- current stripping. The model uses a gravity flow system from one stage to another and air lift pumps to recirculate organic and aqueous phases. A novel pump/mixer system is used to transfer solutions from the mixer compartments to the settler compartments. The model has proven valuable in the teaching of solvent extraction principles.

Jan 1, 1984

By Restarick C. J & Stewart P S B, Kelsall D. P

Over a four-hour period of steady plant operation samples were taken at regular intervals from points within the grinding and flotation circuits. Size fractions of each composite sample were analysed for lead and zinc values and a comparison made of the behaviour of the lead, zinc and gangue minerals, size by size throughout the whole circuit. Analysis of the breakage behaviour using dynamic mathematical models gave the rates of breakage of each size fraction of each main component. Simulated grinding experiments showed that the main grinding circuit had sane reserve capacity. In the lead flotation circuit all lead values between 150 mesh (Tyler) and 5 microns had excellent flotation characteristics, and a major proportion had a high rate of flotation which was practically the same for all sizes. Increase in overall lead recovery would require improvement of the flotation behaviour of ultra-fine lead minerals. These were slow floating and were responsible for approximately half the lead losses in the final zinc concentrate and one third of the lead losses in the final tails.

Jan 1, 1980

Blasting in Norwegian mines is often carried out by contractors who tend to look for the cheapest solution, without concern about fragment quality. The requirementsfor a contractor are usually only related to the maximum size of boulders and the quantity per month. Even when the owners of the mine are responsible for blasting, very little effort is made to optimise the blasting process. This paper presents test methods which were used and results from small-scale and full-scale blasting tests. In the small-scale tests, cubes 500 x 500 x 500 mm of four different rock types were blasted in a chamber, using two types of dynamite explosive. The velocity of detonation (VOD) for the dynamite explosives was 3000 m/s and 6000 m/s respectively. Three cubes of each rock type were blasted with each type of explosive, and a total of six cubes of each rock type was used. The entire muckpile (approximately 350 kg) was- sieved and weighed after each blast and fragments between 8-16 mm were tested for impact values and flakiness. The results of these tests clearly showed improvement in fragmentation the closer the acoustic impedance ratio of the explosive (VOD x density) over the rock (Cp density) was equal to one. The results also showed that the quality of the fragments (in terms of impact values) tends to be better when the cubes are blasted with the high velocity dynamite.

Jan 1, 1995

In current mining practices it is desirable to bring about a substantial increase in both rate of face advance and productivity, thus compelling the mine engineer to consider better and more productive ways of mining. Transportation plays a vital role in achieving improved productivity. This paper focuses on horizontal transportation systems. Horizontal transportation is defined from the shaft station area to the end of the stope cross-cut. Traditionally, horizontal transportation is inefficient in comparison to vertical transportation efficiencies and accounts for a high proportion of South African mine accidents. Thus, the role of horizontal transportation has been investigated in detail, as it offers the greatest chance for improvement. The purpose of the paper is to provide a best practice guideline for the design of horizontal underground transport systems. It is intended that the document be used by mine designers and planners as an aide memoir during the design process and benefit may well be gained from retrofit and reorganisation activity. The paper looks at transport systems suitable for deep level gold mining in South Africa and evaluates such items as management, scheduling, and haulage systems. Current transportation systems for personnel, material and rock transportation are evaluated, gaps in technology highlighted, and recommendations made.

Jan 1, 2003

An understanding of the way that solutes are transported in mining or natural environments is essential to the development of sound strategies for managing waste disposal. Research on miscible pollutant movement in unsaturated porous media is carried out both experimentally and numerically. Results of numerical modelling are obtained by solving the groundwater flow equation and the solute transport equation. The finite element method is employed and comparisons between simulation results and experimental data are found in remarkable agreement.

Jan 1, 1995

JUDGING from the attitude of past and present Parliaments in Australia, it is a' reasonable assumption that encouragement of the principal industries has been adopted as a main principle in the government of the country, but while in most cases bonuses, subsidies, and other means have been proved successful and become recognized as established methods in the case of mining, which is undoubtedly one of the most important industries, the question is complicated by difference of conditions and variable quantities, and it can scarcely be said that any system has been proved generally successful. Indeed, it would not be a very extravagant statement to assert that problems connected with affording direct monetary assistance in aid of mining development, and at the same time devising a system adaptable to the varying conditions to be met, are, in every State of the Oommonwealth, matters continually exercising the minds of those concerned in providing and ailocating such assistance ie Parliament on the one hand, and the Department of Mines on the other.True, there are methods in vogue of granting State assistance to the mining industry which have undoubtedly been successful, but it is in most cases questionable whether the beneficial results following successful expenditure in one direction have compensated.

Jan 1, 1911

Design of cemented fill in mining is often carried out without any consideration of the structure of the fill. The composition of cemented fills varies in the stopes due to the placement method, and the strength of the fill in the laboratory depends on the density, orient- ation, moisture content and drainage conditions. Within each stope there are definite zones and the structure of both cemented rockfill and cemented hydraulic fill has to be defined for each zone and the field conditions simulated in the laboratory. Structure also affects fill permeability and compressibility. From a study of the cemented fill in place, the effect of changes in the placement methods can be seen and then controlled to improve fill performance and economy. These features of cemented hydraulic fill and cemented rockfill behaviour are discus- sed and illustrated through reference to field and laboratory work undertaken at Mount Isa.

Jan 1, 1973

A generalised mathematical model for hydrocyclone classifiers was developed by the author (Nageswararao, 1978) using dimensionless groups which include phenomenological characteristics as independent variables. This model is incorporated in JKSimMet, the steady state mineral processing simulator developed by JKTech.Recently, when this model was rewritten (Lynch and Morrell, 1992), in terms of variables other than those used by the author, a few errors have crept in. For example, while the exponent of (Du/Dc) in the equation for d50e should be negative (-0.47), it was recorded as positive (0.47). Also, the exponent of (DoIDe) in the equation for pressure drop should be 0.67 and not 0.60. In the same equation, the exponent of Dc would turn out to be -0.10 and not 0.15. These are clearly attributable to typographic and rounding off errors, while transforming the original equations.More recently, Cilliers (pers comm) has done a comprehensive evaluation of the major semi-empirical models for hydrocyclones.He observed that the major difference between the cyclone model developed by the author and other models lies in the method of quantifying the effect of spigot diameter on d50e. He noted that while all other models predict an increase in d50e with a decrease in the spigot diameter, the model as cited by Lynch and Morrell (1992) predicts just the opposite. However, he conjectured correctly that the discrepancy could be due to a typographic error. As the model is still unpublished, it is felt that the original model equations should be recorded with the correct exponents, so that errors in predictions other than those due to the limitations of the model itself could be avoided. They are given hereunder.

Jan 1, 1995

By J Rowland, B Belle, M Webber

The Australian underground coal industry has experienced substantial improvements in longwall productivity and, as such, the methods of providing a safe and productive mine environment have needed to evolve and develop. Whilst the primary method of controlling atmospheric conditions is by airflow it has become impracticable or impossible for the majority of Australian longwall mines to contend with all environmental hazards with primary ventilation alone.If the ventilation circuit cannot provide a safe and productive mine environment at an acceptable cost and circuit duty then supplementary controls are required. Examples include pre-gas drainage, post-gas drainage, gas utilisation, refrigeration and innovative dust control systems. Of the 21 longwall operations surveyed in Australia, there were 13 in New South Wales and eight in Queensland.This study represents a timely opportunity for the industry to examine the primary and supplementary ventilation systems implemented in Australian longwall mines and to discuss how to equip the industry to successfully face the future of underground longwall ventilation management in Australia.CITATION:Webber, M, Belle, B and Rowland, J, 2017. Australian longwall ventilation systems, in Proceedings Australian Mine Vent Conference 2017, pp 301–308 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017