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By Morrison R. D, Davis J. J, Fraser B, Kojovic T

1991 saw the completion of a three-year $1.1 million research and development program in mineral sands beneficiation, funded in two associated projects by the Australian mineral sands industry through AMIRA, and carried out by the Julius Kruttschnitt Mineral Research Centre. It is believed to be the largest R&D project in mineral sands ever conducted by a university research group. It covered dry plant operation, and delivered several products to the industrial sponsors, including: ò A detailed characterisation of the radiation properties, mineralogy and size distribution of inhaleable dust arising in dry plants. ò New process models of magnetic and electrostatic separators. ò New on-line instruments for elemental assay (in association with AMDEL) and bulk conductivity measurements of dry process streams. ò Demonstration and evaluation of the Magstream magnetohydrostatic separation technology.

Jan 1, 1992

By J. W. Leonard

A mine's productivity can be significantly increased by using physical and chemical methods to increase the bulk density of newly mined coal. Increases in coal bulk density allows greater amounts of coal to be placed in ships, barges, railroad cars, trucks, shuttle cars and scoops. Increased bulk density can help increase productivity by increasing throughput of container-based, materials-handling systems. Small, easy-to-achieve changes in mining operations are required to obtain the increased productivity. This article deals with chemical methods used to increase coal bulk density. The results and discussion are based on experiments performed in the laboratory. Research at the University of Kentucky using a chemical method shows that an increase of about 15% in bulk density can be achieved using typically small quantities of commercial reagents. This increase in bulk density can produce a proportional increase in the productivity of a mine.

Jan 1, 1992

By R. A. Bullivant

Roger Bullivant Piling Limited has started 1992 with the introduction of the CONE PILE into its range of precast concrete foundation techniques. Since the establishment of its Piling Division ten years ago, alongside the original Underpinning Company, a commitment to innovated development has seen a steady growth in Roger Bullivant's activity in piling, ground treatment and general foundation engineering. Over the last four years, £1.2 million has been invested by the Bullivant Piling Division into research and development in the field of precast piling and other foundation systems. The goal has been to develop economically attractive systems tailored to our clients design requirements and, wherever possible, unique to Roger Bullivant Piling.

Jan 1, 1992

By Song Yong Jin

The Jurassic coals at Datong are characterised by their strong, massive sandstone and conglomerate roofs which fail suddenly over large areas, crushing pillars and creating destructive windblasts, collapsed areas have exceeded 180,000m2 and windblasts have extended over one km underground and 200m on the surface and have been accompanied by subsidence troughs on the surface. Scientific analysis has researched premonitory signs of caving and the nature of windblasts leading to considerations of alternative mining methods and ways of dissipating the energy of windblasts to reduce their damage and danger.

Jan 1, 1992

By Das S. C

A detailed study was undertaken on the effect of Fe+3 in combination with LIX64N during copper electrowinning from sulphate electrolytes. The results show that the presence of Fe+3 not only affects the current efficiency during copper electrowinning but also affects the cathode quality. The effect is enhanced by electrolysis parameters like temperature, circulation rate, current density, etc. No significant effect was found from the presence of Fe+2. The presence of Fe+3 along with LIX64N causes a synergistic effect and results in a drastic fall in current efficiency. Moreover, cathode quality is also affected. A pyramidal structure is favoured in the presence of Fe+3 but the presence of LIX64N along with Fe+3 promotes a ridge structure. Addition of thiourea not only causes modification of cathode deposits, but also a rise in current Efficiency.

Jan 1, 1992

By A. Hinde, M. Moys, L. C. Woollacott

The material-balance smoothing technique is applied directly to the problems associated with the evaluation of the performance of backfill-preparation plants. A computer package specially designed to assist the process engineer in such evaluations has been developed. The usefulness of the technique as compared with other methods for the extraction of meaningful information from backfill-plant data is demonstrated.

Jan 1, 1992

By D. R. Spears

As part of its mission to develop technology to assure a continuing supply of minerals, the US Bureau of Mines has investigated the flocculation of a Stillwater, MT, chromite ore. The ore was flocculated at different solids contents and at different stirring speeds to determine the importance and effect of hydrodynamic factors. In acidic and basic pH, the chromite ore was flocculated with high molecular weight polyacrylamides differing in the degree of hydrolysis. Polyacrylamides were found to bind to chromite ore particles through hydrogen bonding. The anionicity of the polymer and the pH affected the degree of polymer-particle interaction, which in turn affected polymer conformation at the surface. A polymer conformation with many loops and tails was used to explain high flocculation efficiency. It was found that such a conformation could compensate for poor hydrodynamic conditions.

Jan 1, 1992

By M. P. Rennick, D. M. Burton

Abstract -The Murray Brook massive sulfide deposit, which was the first geochemical discovery in the Bathurst camp, is one of the largest sulfide deposits in the area. The massive sulfides are hosted by quartzose metasedimentary rocks in the lower part of the Ordovician Tetagouche Group. This thick succession of sedimentary rocks is overlain conformably by felsic volcanic rocks, and is structurally overlain by mafic volcanic rocks. The massive-sulfide body is polydeformed, but primary metal zoning is still discernable and may permit future exploitation of discrete lead-zinc and copper zones. Although it was discovered in 1956, the deposit was not developed unti11989, when Murray Brook Resources commenced processing of gossan containing precious metals. Recovery of gold, silver, and mercury is accomplished by indoor vat leaching on a year-round basis.

Jan 1, 1992

The A J Parker Cooperative Research Centre for Hydrometallurgy has recently been established by a major grant from the Australian Commonwealth Government. The participating institutions in this centre are the CSIRO Division of Mineral Products, Curtin University of Technology, Murdoch University and the Chemistry Centre (WA). The Australian Mineral Industries Research Association is also a partner. Information is presented about the research activities of the Parker Centre, which are focussed on the solid/solution interface. Three research programs have been established in the areas of leaching, precipitation and surface processes (adsorption). The initial projects within these three programs are described. Details are also given of the Centre's education program which include honours degree training, masters and doctoral degrees by research, a masters degree by course work and workshops. The importance of collaboration with industry to the successful operation of the centre is stressed.

Jan 1, 1992

By Thomas F. Nederpel

The production of zinc and zinc-aluminum coated strip can be reasonably accomplished on a single operating unit. However, if the hot dip coating line is equip d with only one mo 7 ten metal holding furnace, it is necessary to transfer liquid metal of different chemistries and reintroduce virgin material to obtain the 18" necessary balance of elements in the bath. Dofasco produces Galvanize and Galvalume on a coating line with a sin le liquid metal furnace and has developed not only an efficient liquid metal trans& system but also an effective means of reutilizing the zinc-aluminum mixtures without detrimental quality affects.

Jan 1, 1992

By G. Milojcic

The opencast lignite mines in the Rhinel and Di strict/Germany are equipped with the continuously operating bucket-wheel excavator - conveyor - spreader system. High productivity requires large capital expenditure on main mine equipment as a precondition for efficient mining. In operation, the technology employed leads to a particular cost pattern which is quite different from that of other industries. Labour, auxiliary equipment and mobile vehicles are the most important cost factors which can be controlled by the management. In this respect information processing computer systems are used for systematical and interpretable representation of operational tasks and jobs both in planning and work preparation and in recording the operational data describing the work result and the use of resources. Another aim of the project is to relieve the middle management of major part of its administrative routine work. Job-related work planning and data recording open up various possibilities of analyzing the operational procedures. This analysis shows, for example, what auxiliary machines are particularly suitable for specific tasks, and working groups can be organized so as to take account of the different skills of individual employees for the sake of an optimal work product. Computerized information processing provides the decision makers with topical information related to their respective responsibilities. The mining department of the Hambach opencast mine is the first user of the PERMAD system. Due to the favorable evaluation it has been decided to introduce PERMAD in three other mines in the course of 1992/93.

Jan 1, 1992

By C. I. Everson

The Elkhorn mining district is located 35 kilometers southeast of Helena, Montana, on the southeast edge of the Boulder Batholith. Geologically the district consists of a folded sequence of Paleozoic limestones and shales which have been thermally metamorphosed and altered by monzonite to diorite intrusives related to the Cretaceous Boulder Batholith. For the most part, the skarns are associated with metasomatic: replacement of calc-silicate hornfels, diorite and marble by iron rich, dark green pyroxene, garnet, sulfides, the district contains excess of 30,000 Kg.

Jan 1, 1992

Robe River Mining manages a large open pit iron ore mine in the Pilbara region of the North-West of Australia. The mine is managed for various joint venture participants.In July 1986, Robe River Mining made various changes to its management philosophy, which were heavily publicised in the media at the time.As a result of those changes to its management philosophy, Robe River Mining has been able to dramatically increase its production output, productivity, and safety performance without having to resort to major capital outlays and without the benefit of restructuring of applicable industrial awards.

Jan 1, 1992

By S. Shrivastava

A structure based model has been developed for the prediction of viscosities of K20-B20, melts. These melts exhibit an anomalous behavior of viscosity with continuous variation in B203 content. A maximum and a minimum are observed at low temperatures, which disappear on raising the temperature above the softening range. The addition of K20 to the borate melts causes two opposing phenomena: (1) depolymerization effects and the related breakdown of network structure resulting in the formation of singly bonded oxygens, which weakens the structure and hence causes a decreases in viscosity, and (2) the formation of four coordinated borons (BO4 tetrahedra) which strengthen the structure leading to an increase in the viscosity. The structural changes taking place in these melts on varying the temperature and the alkali content have been reviewed and are incorporated in developing this model. The predicted values are in excellent agreement with the experimental values over the whole temperature and composition range.

Jan 1, 1992

By R. M. Moon

Neutron scattering has played a crucial role in advancing our understanding of rare-earth materials. It has provided a detailed description of the rich array of exotic magnetic structures; it has confirmed the accuracy of theoretical wave functions for the 4f electrons; and it has provided fundamental data on the collective magnetic excitations in these materials. The fundamental property of the neutron which has been exploited in this work is the magnetic interaction which exists between the magnetic moment of the neutron and atomic magnetic moments on individual rare-earth atoms. This interaction produces scattering of neutrons in a manner closely analogous to the scattering of X rays by atomic charge distributions. In a material exhibiting long-range magnetic order, Bragg diffraction peaks will appear at scattering angles determined by the periodicity of the magnetic structure. The Bragg intensities are determined by the magnitude and relative directions of the atomic moments. The rare-earth metals and alloys are characterized by sinusoidal modulation of magnetic moment components which can be combined in various ways to produce a variety of magnetic structures. The periodicity of these modulations is frequently not related simply to the underlying periodicity of the chemical structure. The major features of these structures are explained by the combined, and sometimes competing, exchange and crystal-field interactions. At a more fundamental level, neutron diffraction also gives information on the spatial distribution of a magnetic moment in a rare-earth atom. This moment comes from the 4f electron shell, and accurate measurements of the neutron scattering amplitudes have been used to check the accuracy of atomic wave function calculations for the 4f electrons. It was found that relativistic Dirac-Fock calculations are in excellent agreement with the experimental results. Collective excitations of ordered magnetic systems are described in terms of spin waves, which are sinusoidal modulations in space and time of the direction of the ordered moments. Inelastic neutron scattering is used to measure the energy and wave length of these collective excitations. Analysis of these data gives direct information on the interatomic interactions responsible for the magnetib properties of these materials.

Jan 1, 1992

Gippsland has perhaps the most colourful history of exploration of any area in Australia. Hydrocarbons were first discovered in the Gippsland Basin in 1924 when a water well at Lakes Entrance encountered oil and gas shows. In 1942, the Commonwealth and Victorian Governments, in an effort to supplement a wartime oil shortage, sank a shaft near this well and produced 8000 barrels of low gravity oil up to 1956, when the field was abandoned. A total of 64 shallow wells had been drilled in the Lakes Entrance area by that time. Elsewhere in the onshore Gippsland Basin, 30 wells were drilled from 1925 to 1941. In 1960 BHP Ltd was granted an exploration permit covering much of the offshore area of the Gippsland Basin. Esso Australia Ltd joined BHP in 1964 and drilled the Barracouta-1 gas discovery in 1965. Since then over 100 exploration and appraisal wells have been drilled in the basin resulting in the discovery to date of some 3.6 billion barrels of recoverable oil and 8.8 trillion cubic feet of recoverable gas (Current remaining recoverable reserves are 906 million barrels of oil and 5.7 TCF of gas). Exploration in the offshore areas is actively continuing today and new discoveries are still being made.

Jan 1, 1992

By Zhang Youdi

A two-step approach has been developed for surface mine short term planning by the authors. The first step is mid term control and planning by the use of Goal Programming. This step gives optimal results for mid term planning (i. e. yearly or quarterly mine plan) as well as a macro control for short term planning (i. e. monthly or weekly plan.) The second step of the approach deals with short term production scheduling by the application of CAD technique and Systems Simulation. An interactive color character graphic design system has been developed with a software package. The menu-driven and module- structured package provides sufficient functions for surface mine short term planning and makes the model very flexible and user-friendly. This model has been applied to a large surface coal mine for short term planning optimization. Satisfactory results have been obtained. It is concluded that for complicated mining conditions this two-step combined approach gives an optimal control of mid term planning, makes the short term planning easier to avoid blindness; it has been proven that the Goal Programming is a powerful tool for solving multi-objective decision-making problems; guided by GP mid term planning, the CAD technique and simulation software package for short term planning are able to be concentrated on their practicality and flexibility.

Jan 1, 1992

By J. Ye

A comprehensive flotation study has been carried out on a Chinese fluorspar ore using the packed flotation column developed at Michigan Technological University. The results are compared with that of a conventional mechanical flotation method on the same feedstocks. Key factors controlling flotation performance of both methods are evaluated based upon a simple statistic design. The flotation concentrate produced in one stage of the packed column has 4-S% higher recovery and much lower silica impurity content than that produced by up to six stages when a conventional mechanical cell is used. The results also show that the packed column flotation process is particularly suitable for recovery of finer fluorspar particles.

Jan 1, 1992

By Hans Prem

There has been a dramatic development in the field of magnetic materials in the last 10 to 15 years. Capacity improvement of electronic components especially required an increased production of "rare earth magnets", e.g. samarium-cobalt (SmCo) magnets and neodymium-iron-boron (Nd-Fe-B) magnets. We participated in this development and learned how to construct systems for the dry processing of these magnet materials. In the meantime we have supplied a large number of these systems for coarse and fine milling. Processing is effected in a protective atmosphere in order to avoid oxidation and thus deterioration of the magnet materials.

Jan 1, 1992

The statistical nature of the variability in detonation times of pyrotechnic delays is discussed, and how to evaluate the probability of required detonation intervals is shown. Some methods (analytical and stochastic) are given for designing blasts to ensure that any adverse effects on the variability in the delays is taken into account and minimised. Using computer models of blasts, detonation simulations can be used to check the initiation sequence for the probability of sequence reversals, indicating areas of high blast damage potential. Charge consumption rates, which relate directly to the resulting vibration levels, can be examined for their susceptibility to variation from delay variability. Models that synthesize vibration waveforms for production blasts, when taking delay variability into account, indicate the difficulty in vibration level prediction.

Jan 1, 1992