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By Denholm W. T, Rankin W. J

The reduction of zinc from lead blast furnace slags using hydrogen was studied at 1300¦C as part of a laboratory investigation of zinc fuming. To perform the experiments, 300 g "spent slag" was melted in a crucible. Hydrogen was then injected into the slag through a lance and fresh blast furnace slag was added regularly in small quantities over a period of 40 minutes. Zinc added in the fresh slag was reduced and the zinc level of the bulk slag attained a steady state value of between 1 and 9% after about 10 minutes, depending on the gas injection rate. Because of the high reactivity of hydrogen, bulk supply of hydrogen to the slag was the rate limiting step at the flow rates used and it is believed that the gas-slag reactions in the system were at equilibrium. A partially/stabilized zirconia cell with a Ni/NiO reference electrode was immersed in the slags during the experiments and the steady/state oxygen potentials of the slags were measured. By using the experimental oxygen potential values and calculated values of the steady state concentrations of zinc in the offgas, the activity of ZnO in the slags was calculated from the Gibbs's free energy change for the reaction:

Jan 1, 1989

BECAUSE of the attention given in recent years to the flotation process, there is an extensive range of equipment available to any staff detailed for: the design of a flotation mill. This statement applies not only to the flotation machines, but also to equipment for crushing and grinding, elevating the pulp, dehydrating of concentrates, and the methods of driving the various equipment.Distributed through the Proceedings and Transactions of various metallurgical societies and journals there are many excellent descriptions of flotation mills, their equipment and performance.Whilst these articles describe-in many cases in detail-the equipment in the mills to which they refer, the reasons which govern the choice of each particular equipment are not usually given.

Jan 1, 1929

High resolution seismic profiling has proved a cost effective tool for defining the structure and seam geometry of Late Cretaceous-Late Miocene age lignite deposits in the South Island of New Zealand since 1981.In 1985 a total of 45 km of Mini Sosie seismic reflection was carried out in the Benhar, Hawkdun and Ashers-Waituna deposits as part of a major multidisciplinary resource investigation funded by the Liquid Fuels Trust Board. For each deposit the seismic programme involved integrating four or more intersecting Mini Sosie traverses with a grid of 1000 m spaced geophysically logged drillholes. The objective was to detect faults, with displacements ranging 30 - 100 m, which might impede mining using bucket wheel excavator systems at depths down to 300 m below surface.In general the quality of processed seismic data was high and with the assistance of ynthetic seismograms and other geological information, it was possible to identify a number of significant previously unknown faults. The success of this seismic programme ha shown that high resolution seismic profiling, used in conjunction with relatively low density drilling, can produce valuable structural and tratigraphic information at an early stage of open pit mining investigation.

Jan 1, 1989

By A D. Paktunc

The surface reactivity of underwater deposited, high-sulfide copper mine tailings was evaluated under fresh and saline water cover conditions by measuring the surface and pore water quality as a function of time. The experiments were conducted in aquarium type lysimeters having a shallow, well-aerated water cover up to approximately 0.25 m over the tailings. Natural lake water was used for the fresh water cover and seawater for the saline water cover scenarios. The tailings showed significant surface reactivity and oxidation under both fresh and saline water cover conditions. The surface water quickly became moderately to highly acidic, and surface oxidation of the tailings resulted in increased dissolution and release of sulfates, iron (total), calcium, magnesium, aluminium, manganese, copper, nickel, zinc, lead, cobalt and silicon to the water covers. A moderate to slightly increased loss of total sulfides, including pyrite, chalcopyrite and sphalerite, occurred in the tailings surface layer to a very shallow depth. In comparison to the fresh water cover, the complete acidification of the saline water cover was delayed by approximately 30 - 40 days because of its additional available alkalinity. Whereas the rate of surface water acidification and release of aluminium and silicon were moderately reduced under saline water cover conditions in comparison to those for the fresh water cover, the release of calcium, magnesium, iron (total), copper, nickel, lead, zinc, sodium and potassium were enhanced. The mass transfer fluxes for dissolved copper, nickel lead, zinc and iron (total) from the tailings substrate to the surface water cover following surface water acidification were higher by 50 per cent or more in the saline water cover than those in the fresh water cover. This release was also reflected in moderate loss of pyrite, chalcopyrite and sphalerite in the very shallow upper surface layer of the tailings at the tailings-water interface, although the loss of pyrite in the surface layer was less pronounced. In both cases, the dissolution of aluminosilicate minerals moderated, to a certain extent, pH and acidity in the water cover.

Jan 1, 2003

During the past five years there has been a transformation in the operating costs which apply to narrow vein mining. Mechanised methods including sublevel uphole retreat and narrow vein cut and fill are now proven. Other methods, such as vein mining by horizontal drilling from a raise platform are currently being tried in Australia.The important factors which affect the cost and appropriateness of each method include: ore continuity, the planarity of the wall contacts, relative hardness of ore and wall rocks and the dip bf the deposit.Drawing on current operating costs from a number of mines and on recent feasibility studies, a methodology for estimating the costs of narrow vein mining is presented. These costs are then placed in their economic context with regard to ore grade and mining rate.

Jan 1, 1993

This paper introduces a classification of gold orebodies, and comments on the importance of cutting high grade values, the choice of an appropriate ore reserve method and the necessity for producing recoverable ore reserves by considering the mining policy. The author stresses the importance of obtaining the appropriate information from the data relevant to a particular deposit as opposed to transfering parameters from one deposit to another.

Jan 1, 1987

By Tilley J. L, Chicu D

The development of the Yallourn East Field brown coal open cut has involved the adoption of novel investigational programs into coal qual- ity. For example, weighted average coal property statistics for key proper- ties are determined by using a unique blend of traditional and 3-dimensional geostatistical estimation. Predicted property values are made freely available from the mainframe computer in the form of kriged esti- mates of 60 000 tonne coal blocks. Geostatistical predictions are being incorporated within the Mincom/Intergraph CADD system which is used for mine design. Key properties relating to coal type, moisture, and ash have been evalu- ated to provide the required data for the design and operation of both the open cut and the power stations as well as the briquette plant.

Jan 1, 1989

By Valenta R. K

Copper-gold deposits associated with iron oxide rich rocks (ironstones) form a distinctive and significant ore association which occurs widely, but not exclusively, in the Proterozoic. The ironstone association is geochemically distinct from the BIF-hosted gold association (Phillips and Groves, 1983). Not only is the former association higher in its copper and commonly uranium, FEE, ¦bismuth, molybdenum contents, but also the ironstones in many cases do not originate as chemical sediments. Although both associations form in metamorphic environs, they reflect differing tectonostratigraphic settings and with consequent differences in ore-forming fluids and ore-forming mechanisms. This paper discusses the nature and origin of the ironstone-related copper-gold association, with particular reference to the Tennant Creek district in northern Australia, and emphasises the two stage origin of mineralisation. The genetic model developed has significant implications for other ore-bearing environments.

Jan 1, 1990

In the future to excavate sufficient coal for power generation, two dredgers would be required to dig overburden or interseam 70010 of the time and three dredgers 40010 of the time. One overburden system was not adequate for this requirement, making coal production reliability vulnerable. TS5 spreader is the new machine element of this system. The selection of the best type of machine configuration to suit the application was then subject to an internal SECV VE Study, a registration of interest and a tender for two machine alternatives. This paper outlines the reasons why SECV planned the Secondary Overburden System and how the Krupp machine met these requirements. It also identifies the main design features of the machine and its constructability which will allow the machine to be operational by the end of May, 1990.

Jan 1, 1989

By Draper J. J, Lang S. C

Regional geological mapping and facies analysis of the Late Devonian to Early Carboniferous Keelbottom Group of the Burdekin Basin have resulted in a depositional model representing six siliciclastic-carbonate facies. The six facies represent alluvial fan, braidplain delta, siliciclastic shoreline, siliciclastic shallow marine, restricted siliciclastic/carbonate shelf, and carbonate shoal depositional environments. These facies are identified in the Star beds which are equated with and included in the Keelbottom Group in this paper. Facies are repeated throughout the Group, as a result of two transgressive-regressive cycles.The first transgression recognised in the Keelbottom Group began in the mid-Famennian, and followed deposition of the Late Devonian Dotswood Group. It was marked by the deposition of Siliciclastic Shoreline facies in the basal Myrtlevale Formation, which was succeeded by Siliciclastic Shallow Marine facies at the peak of the transgression. The return of Siliciclastic Shoreline facies in the upper part of the Myrtlevale Formation marked the onset of the first regression, which resulted in the progradation of Braidplain Delta facies from the northwest of the basin. During the peak of this regression, deposition in the western part of the basin was dominated by Alluvial Fan facies.

Jan 1, 1990

The techniques originally developed to process digital images of Mars, later gained widespread acceptance when applied to Landsat data: they are now making a significant impact in fields of geology outside remote sensing. The three ingredients of success are seen to be firstly, the perceptual attributes of image displays and the use of colour; secondly, the absolute ability to register data from a variety of sources; and thirdly, the speed of specialist "interactive" digital image display systems. The future lies in further exploiting these attributes through a Geographic Information Systems (GIS) approach to data handling, integration and display.

Jan 1, 1986

Gold mineralization belt of eastern China in the adjacent part of the northwestern Pacific rim is orientated NE to NNE and as-sociated with Mesozoic faults and igneous intrusives and Mesozoic to Cenozoic volcanism and subvolcanism extending more than 3000 km in length and 300 to 800 kni in width affected by the movement from the Pacific Plate subducted against the Asian Plate.The relative movement between the Pacific and the Asian plates give rise to two types of fracture zones, the tensional ones providing the space for the formation of fissure-filling type of auriferous quartz veins and the shear zones providing the space for the formation of hydrothermal replacement type of gold de-posits in Shandong Peninsula. The fissure filling type of quartz vein, is represented by Linglong gold deposit which is hosted in Mesozoic Linglong Granite and consists of hundreds of quartz veins filling fractures trending NE to NNE and the hydrothermal replacement type is represented by Sanshandao gold deposit which is hosted in crushed and hydrothermally altered Mesozoic Linglong Granite in contact with Archaean metamorphic complex of Jiaodong Group along a Mesozoic upthust fault zone trending NE.

Jan 1, 1990

By McClarnon D. J

This paper aims to provide the reader with an insight into the field of computer graphics and Virtual Reality (VR), and show how both have been applied to the general area of Free Steered Vehicle (FSV) operations underground. It first explains this developing computer technology and explains its advantages over existing CAD based solutions. This paper deals with the graphical applications and implications of building models within a computer's memory. It then continues to describe the problems with Free Steered Vehicle operations. The work already carried out in the field of VR is explained, and the production of a VR system addressing the problems with fitting cameras to aid the driver's field of view is detailed. Another possible use of VR is also explained - the concept of risk regions, demonstrating its uses in the examination of proposed operational methods. Examples of possible uses are given, and its potential advantages over existing methods discussed. A case study of a computer-generated video involved with the safety of operations of FSVs is also presented. This addresses the precautions that pedestrians should take to ensure safe working in areas where FSVs are operating. This paper then concludes with possible further applications for computer graphics and VR, and the on-going research into these two technologies.

Jan 1, 1995

of the multitude of physiographic problems of immediate interest in volcanic terranes, it is the origin of the magma forming the magnificent volcanoes that is perhaps the most mysterious. Unlike anywhere else on earth, the possible locations of magma production beneath the convergent margins are strongly limited in depth and areal extent. Yet the exact process by which magma is produced still stands elusive, even in light of tremendous gains in analytical and physical insight. The principal aim here is to discuss some of what has been revealed about the physics and chemistry of the origin and evolution of island are magmas.

Jan 1, 1987

By Senanayake G

A sample of crude copper powder produced by the CLEAR Process was refined by dissolution and recovery in sulfate media using the Parker Process. The Parker Process offers an alternative method of copper recovery to electrorefining and allows a range of Eh and pH conditions to be used to provide further discrimination of impurities. High purity copper powder was recovered by the Parker Process even in the presence of added impurities when the Eh and pH was maintained near constant throughout the refining step.

Jan 1, 1984

By Moort van J C

A new low-intensity magnetic separator which operates by spinning particles in a continuously rotating magnetic field is able to reduce particle entrapment of non-magnetics to an almost insignificant level. In such separators the removal of ma

Jan 1, 1997

Rock bolting provides a supplement or alternative to conventional timber and steel supports. The tensile strength of the bolts lies within a range established by manufacturing quality control. Rock bolt testing determines the ability of the rock, anchor and individual bolt as an assembly to accept load. The.test is performed to the yield strength of the bolt or anchor and deflection is observed. The anchorage index, inches deflection per 1000 lb load increment, is a measure of anchorage quality. This allows comparison with anchorages under ideal conditions. It also permits comparative assessment of roof bolt anchors in a particular environment.

Jan 1, 1971

By Tran T, Young D

During the processing of gold, effluents that are discharged into the tailing dams contain free cyanide, metal cyanide complexes of zinc, copper, iron, etc and their oxidised products such as ammonia, cyanate and thiocyanate. A knowledge of how different cyanides behave in the solution is vital to metallurgists working in the area of cyanide waste treatment. Although the free cyanide ion is not stable in aqueous solutions and is expected to degrade in a natural environment by atmospheric oxidation, the metal cyanide complexes, especially of iron, are very stable. The CHEMIX program from the THERMODATA package, developed by the CSIRO Division of Mineral Products, was used to evaluate various copper-cyanide and iron-cyanide systems. The simulation of these systems show how the free cyanide and cyanide complexes behave at different conditions of solution composition and acidity (pH).

Jan 1, 1991

By Duran A, Eggers M. J

It is standard practice in geotechnical studies for mine design to drill a series of inclined oriented boreholes into the proposed pit walls. However, this investigation tool is often used without an adequate understanding of the inherent shortcomings in the method and the many potential sources of error. Of the more commonly used orientation methods in Australia the clay imprint technique is probably the most reliable. Contoured stereographic plots of oriented core data are frequently characterised by diverse pole distributions and low concentration maximums compared with line mapping data. Common sources of error producing these poor results are misinterpretation of orientation marks or imprints, inaccurate marking of the reference line, errors in the structural measurement of the defects, lack of continuity information and blind zones sub-parallel to the borehole direction which correction methods frequently do not fix. Line mapping is the preferred method of structural data collection due to the lower overall cost, availability of continuity information and higher accuracy. The projectability of field mapping data to final wall positions can be assessed with a good understanding of the regional geology and local structural patterns. Where field mapping is not possible due to a thick regolith cover, core orientation should be carried out by experienced personnel to minimise the many potential errors.A series of case studies are presented which compare oriented core with mapping and highlight the inherent problems with the technique.

Jan 1, 1992

By Wang QP, Quan YH

Mechanical models are established in accordance with the degree of mining on both sides of the coal pillar, and formulae were derived which calculated the superposition stress distribution and the width of the plastic region. The stability of the coal pillar was analysed and a reasonable size of coal pillar determined, in accordance with the elastic region rate. Further practical examples for the stability of the coal pillar are calculated and simulated.

Jan 1, 1992