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By Chitombo GP

The proposed guidelines on vibration limits that have been circulated by the Australian Environmental Council, demonstrate the need for an extensive data collection and evaluation program to avoid the enacting of abritrary and costly legislation. The operational or practical influence of blast design and overall economic implications of legislation which further reduces permissible levels of ground vibration are discussed. In a typical blasting operation, blast sizes could become smaller and blasting correspondingly more frequent to meet pro- duction demands. Blasthole diameters and charge lengths could be reduced, increasing drilling costs and associated labour costs. Blast size however, is frequently controlled by factors associated with machinery, grade control, pit control, stope size, production contract levels and other factors which cannot be readily changed for operating mines. Blasthole diameters are frequently deter- mined by existing drilling equipment, length of holes (depth of ore or stope size), geological structure and other factors which are not easily changeable. Typical large scale open stoping and strip mining opera- tions are analysed as case studies. The effects of extreme leg- islative limits and the corresponding operational changes with respect to variations in production costs are discussed.

Jan 1, 1987

By Dickson T. J

Slag cleaning is an important part of the pyrometallurgical operations at the Kalgoorlie Nickel Smelter. It is a complex system with many streams of different phases and composition. Some of these streams are very difficult to control and/or monitor. Through the use of a statistical computer package, called Minitab, key relationships affecting the economical operation of the slag cleaning process have been found. Data for the statistical analysis was collected from all possible variables around the appendage.

Jan 1, 1991

The Tick Hill Gold Mine is situated approximately 110 kilometres south of Mount Isa, and 14 kilometres north of the township of The Monument. It was discovered in October 1989 by Mount Isa Mines Exploration in an area which had been targeted as high in potential for copper-gold mineralization.A mining lease application was made in March 1990. Mining, and the construction of the plant and infrastructure, began'in early August 1991 after the lease was granted on 20 June of that year. Commissioning of the plant began in December 1991, and the first gold was poured on site on 31 December 1991.The development of the underground mining operation commenced in January 1992 with the drilling of the ventilation shaft. The access decline was started in March of the same year, with the first ore produced from underground in August.

Jan 1, 1993

By Rieniets S, Somerville J. L

In Morwell Open Cut brown coal mine, the overburden 'firehole' materials which have resulted from ancient coal fires vary-from hard baked clays to firm laminated lacustrine clays. The need to pre-strip designated areas to reduce the slope height and attain safe digging conditions for the bucket wheel excavator operation is now accepted practice at the open cut mine. In this study, the inherent spatial variability of undrained shear strength of the clay materials has been incorporated in a visco plastic, finite element based, probabilistic slope stability analysis. Data on the costs of initial pre-stripping, excavation and slope failure are collected to provide an economic basis for the optimisation of the design of the overburden batters in Morwell Open Cut. This improved stability modelling is enabling costly pre-stripping to be minimised while ensuring acceptable slope stability conditions and minimising the risk to personnel and plant.

Jan 1, 1994

By Raczej I, Defant M

Pre-Miocene igneous rocks from the Phili pine island arc are characterised by 87Sr/86Sr and 143Nd/144Nd ratios typical for intra-oceanic island arcs where sediment involvement in the magma genesis was minor. Lead isotopic ratios are similar to Indian Ocean MORB (Mukasa et al., 1986a,b). Pliocene to recent volcanics, however, have more radiogenic Sr and Pb and less radiogenic Nd, except for the volcanics of the Bicol Arc, which have similar isotopic signatures as the Pre-Miocene rocks. We suggest that Pre-Miocene magmas and Bicol-Arc magmas have been generated in response to the subduction of the Philippine Sea Plate, their isotopic characteristics reflecting the composition of Philippine Sea crust. The Bataan arc magmas may reflect the larger amounts of sediments available for subduction in the South China Sea, while magmas of the Mindoro Arc, which are characterised by the most radiogenic Sr and least radiogenic Nd, may have been contaminated by slivers of the Mindoro-North Palawan terrane, which have been carried down to mantle depths after the collision of this terrane and the Philippine arc in Miocene (McCabe et al., 1982). This interpretation implies that Nd (and by inference other REE) can migrate from the subducted slab to the mantle wedge. Thus, variable Nd-isotopic ratios in island arc magmas (e.g. Sunda, Lesser Antillas) may not he a primary feature of the mantle wedge but a consequence of the release of Nd from the subducted slab.

Jan 1, 1987

By Parker RJ, Swindells CF

The authors have used the geotechnical study for design of the South Wall of Mt. Newman Mining's Mt. Whaleback Mine to illustrate how geotechnical studies can be economically justified. This is achieved by relating the savings resulting from increased ore recovery and prevention of failure to the cost of the study. An outline of the geotechnical study is provided in the paper, including a brief description of the innovative methods used to investigate geological structure of the mine and descriptions of the methods of slope reinforcement adopted.

Jan 1, 1986

By Roberts C

The satisfactory testing and characterisation of mineralisation amenable to heap leaching, is of prime importance to successful operation of a project. This paper outlines a methodology for assessing material suitability. A general model is used for classing material types for suitability for treatment and for economic analysis. The four levels of these are overburden, oxide, transitional and unoxidised materials. During exploration, reverse circulation (RC) drilling can be used effectively to define these zones by a combination of logging, analysis and provision of cuttings for column leach and bottle roll trials. RC cuttings can he used effectively for column leach trials, when calibrated against conventional processing-sized samples, obtained from surface. Tbis allows metallurgical testing to depth and definition of transitional ore types and the base of oxidation, accurately and economically with an acceptable density of samples. The accurate prediction of base of oxidation and variations in recovery with depth and ore types can be used to develop 'economic' pit designs with zones of variable recovery. Petrological studies of leaching results and examination of mineralisation types carried out on concentrates, provide information on gold distribution and physical and chemical constraints. The examination of concentrates can be particularly useful for types of mineralisation when overall gold content is frequently at or below one pan per million. Explanation of anomalous recovery of gold grains in dense goethite and solution-robbing by carbonaceous material can be identified by use of petrological and scanning electron microscope. An understanding of the role of the host rock in leaching characteristics can also he provided by petrology where siliceous or clayey materials can require significantly different treatment.

Jan 1, 1994

By J Hadjigeorgiou

The stability of open stopes in underground hard rock mines is influenced by several factors including the shape and size of the excavation, surrounding stresses as well as the degree of jointing. This paper presents a design methodology for stope analysis in jointed rock masses. The proposed approach relies on geological structural data to construct realistic three-dimensional joint network models. The stability of an open stope is determined based on a limit equilibrium analysis.

Jan 1, 2000

By Leahy GJ, Wright DJ, Player RI

The operation of a one tonne submerged combustion pilot plant for the recovery of copper from anode furnace and converter slags is described and the effects of variables discussed. Using coal as reductant, copper levels of anode furnace slag were lowered to 1% or less, with batch times of approximately 120 minutes. Fluxing with limestone was required to produce a fluid slag at temperatures of 1200 - 1300¦C. For converter slags, reduction to 0.5% Cu or less was achieved in batch times of 35 minutes. The chemistry of the pyrometallurg- ical recovery of copper is briefly reviewed in relation.to copper recovery methods.

Jan 1, 1978

By Fabjanczyk M. W

The design of underground mine roadways (tunnels) requires a detailed understanding of the in situ stressfield, the rock failure modes, the performance characteristics of reinforcement or support members and assessment of the stress state about the roadway. Definition of these factors, together with monitoring of roadway behaviour during both development and extraction operations, allows rational design procedures to be undertaken.The design approach utilised computational techniques to simulate the behaviour of the strata about the opening for a range of anticipated stressfields and various reinforcement options. Field validation studies are conducted to confirm the design expectations.

Jan 1, 1993

By Beattie MJV

Widely diverse mechanisms exist for the action of a range of selective sulphide flotation depressants. Collector desorp- tion, leaching, competitive adsorption, formation of hydrophilic reaction-product coatings, action as reducing agents, and action as lattice-oxidizing agents are discussed. Detailed attention is focused on the latter two mechanisms. Recent works on copper depressants particularly for copper-molybdenum separations, and oxidizing agents enabling arsenopyrite- pyrite separations, are presented and discussed.

Jan 1, 1984

By D A. Kepert, D Clark

During early 2004, Fortescue Metals Group (FMG) began an aggressive exploration and drilling program in the Chichester Range, targeting iron enrichment developed in the Nammuldi Member at the base of the Marra Mamba Iron Formation. The timely recognition by FMG of distinct zones of (hypogene) microplaty hematite (mplH) enrichment overprinted by extensive supergene mineralisation led to an early reappraisal of the geological history of the area and characterisation of the possible structural and stratigraphic controls on mineralisation. Regionally, the Chichester Range dips gently at less than 5¦ to the south, however, detailed mapping shows that this regional limb is overprinted by low amplitude, long wavelength, north/south to northeast/southwest trending folds. The locations of major structures in the Marra Mamba Iron Formation, combined with spectral analysis of known mineralisation, allowed extrapolation and prioritisation of exploration target areas. The delineation under cover and understanding of these structures was enhanced by detailed airborne magnetic data. Recognition that supergene mineralisation was associated with a palaeotopography that continued significantly under cover to the south under sediments of the Fortescue River valley led to the discovery of extensive supergene mineralisation together with additional mplH mineralisation. A model for the landscape evolution and preservation of enriched Nammuldi Member was generated in order to help communicate both the complexities involved with targeting drill holes beneath cover and the potential limits to the lateral extents of mineralisation.

Jan 1, 2005

By Dharmappa HB, Sivakumar M

This paper is concerned with two case histories of wastewater quality management in underground coal mines in the Illawarra region. The first investigation briefly presents an analysis of mine water discharge having an extremely high concentration of suspended solids and consistently high barium concentrations, averaging, 14.4 mg/I Barium, over the sampling period. A laboratory study of chemical precipitation processes has indicated that about 91% of barium could be removed by using ferric sulphate and lime. On the basis of the information obtained from the environmental audit process an alternative water treatment and reuse system incorporating 51% reduction in the water consumption with 32% less off-site discharge has been suggested (Thomas, 1995).The second case history is concerned with the storm water management at a mine situated in the Illawarra escarpment where only 20% of the wastewater generated in the colliery is discharged off-site. Computer modelling of the storm water system showed that 75% of the clean runoff becomes contaminated through poor management practices and causes the process wastewater treatment system to fail in wet weather. Suggested improvements include relatively simple alteration to the coal wash filtration dams which are expected to reduce the periods of inefficient operation of these dams by 95%. The use of storm water diversion channels and detention basins can reduce the overflow volumes by 70 - 100 % for a ten year ARI (Average Recurrence Interval) storm event (Wingrove 1996).

Jan 1, 1998

Epithermal gold mineralisation was discovered at the Muyup prospect during regional reconnaissance exploration in 1986. Further exploration utilising routine techniques of stream sediment, panconcentrate, rockchip sampling and geological mapping resulted in the discovery of five auriferous vein systems located along northwest-trending fault zones. Scout diamond drilling was conducted on two of the vein systems. Mineralisation is hosted by a poorly exposed, mid-Tertiary volcanic inlier composed of intermediate and minor felsic volcanic rocks intruded by intermediate hypabyssal por- phyries. Gold is wholly contained in narrow steep-dipping hydrothermal breccias and quartz vein stockworks in which chalcedonic silica and fine grained quartz is the predominant gangue with minor adularia, carbonate, and sulphides. Alteration zoning is manifested as intense fracture-controlled silicification mantled by narrow clay-rich envelopes which in tam grade outward and downward into propylitic alteration or unaltered host rocks. Late advanced argillic alteration is superimposed on the vein-related altera- tion assemblages. Alteration assemblages and fluid inclusion data suggest that gold mineralisation occurred in response to episodic hydraulic fractur- ing and boiling of low to moderate temperature, dilute alkali-chloride fluids. The Muyup prospect represents the shallow eroded remnants of an epither- mal gold deposit enriched in Au, Ag, As, Sb and Hg. Low sulphur fugacities reflected by vein and alteration assemblages support an adularia-sericite classification (Heald et al, 1987) for this epithennal gold deposit.

Jan 1, 1991

Published information on technical and market developments in the uses of zinc tends to dwell very largely on two groups of uses of zinc - zinc coatings (mainly galvanising) and zinc casting alloys. These two groups account for two-thirds of primary zinc consumption. However, if total zinc consumption is taken into consideration, coatings and casting account for a little over half the total. Either way, the health - or otherwise - of these 'other' uses of zinc can have a substantial effect on the industry as a whole. The aim of this paper is to put the whole market picture for zinc into better focus, concentrating on the factors which can affect consumption in the 'other half' of zinc's markets: ò brass - the third most important market for zinc at around one million tonnes - responds to changes in the economic cycle. It has seen substantial changes in the balance between different forms of semi products, and, in Europe at least, some real market gains; ò zinc sheet - one of the original uses of zinc in Europe - has grown substantially in some countries, but remains almost unknown elsewhere; and ò zinc pigments and compounds are so numerous that - barring the substitution of zinc oxide in rubber - major overall changes in the market are unlikely. The paper examines these markets and assesses their potential and implications for zinc markets as a whole.

Jan 1, 1993

By Fabjanczyk MW, Guy RJ, Tarrant GC

The design of the reinforcement systems required to stabilise mine roadways has developed through the application of field measurement techniques. These techniques have allowed the level of security of a given opening to be determined from an assessment of the loading within the reinforcement, the extent of roof deformation and experience. The design systems developed are now used extensively in a wide variety of geological environment. Recent interpretative techniques have been developed to improve the level of confidence when designing roadway reinforcement. The techniques are particularly applicable for roadways subject to either weak materials or extreme stress levels. A second area of application is where roadway advance rates and hence the timing of reinforcement placement are critical. The newly developed techniques include both analytical and computational models. The validated computational techniques allow a more rational approach to investigation of the effect of varying reinforcement type, timing of placement and density on the level of stability achieved.

Jan 1, 1992

The basic rule for correct design of a sample plant is that all parts of the material being sampled must have an equal probability of being collected and becoming part of the final sample for analysis. However, this rule is often ignored in the design of sample plants to save capital costs. This is false economy, because the samples taken are likely to be seriously biased and the precision may be compromised. The introduction of bias is particularly serious, because no amount of replicate sampling and analysis will reduce bias once it is present and it is often quite difficult and expensive to subsequently rectify the problem due to space limitations around the primary sampling location. This is also true of secondary and tertiary sampling stages, particularly in terms of the relationship between particle size and retained sample mass. The best strategy is to seek expert sampling advice and design the sample plant correctly at the outset.

Jan 1, 2005

By Edwards A. B

This paper presents the results of an examination of four samples representative of the low-lead matte, high-lead matte, lead speiss and antimony speiss, respectively, produced during smelting operations at Port Pirie Smelters. The investigation was undertaken at the request of the Broken Hill Associated Smelters Pty. Ltd., as part of the research programme of the Mineragraphic Section of the Council for Scientific and Industrial Research.Analyses of the specimens are as follows:-

Jan 1, 1949

By C Gypton

This paper gives some insights into what to look for when reviewing feasibility studies. The review by a third party is an important element of the risk management process and may be the last remaining opportunity to uncover errors, or identify and reduce project risks on paper before they are converted to financial disappointments, steel and concrete monuments to process failures or cost overruns. The mining industry has had a spotty record in the area of estimating initial capital costs and operational performance, even though the standard of feasibility studies is generally acknowledged to have improved in the last decades. Third party reviews rarely have the luxury of enough time and unlimited funds, so where should the reviewers focus their efforts to be most effective? Assuming that the project already apparently meets investment criteria, the authors suggest where and how to look among fundamental project parameters for signs that serious flaws exist that have the potential to become project killers. We also give advice on how to review cost estimates without becoming lost in the details. The paper is supported with numerous actual examples.

Jan 1, 2003

The mineralogy, maero- and micro-textures of Thackaringa ore are simple and have many counterparts among base metal-quartz-siderite vein type deposits elsewhere.The ore consists predominantly of galena, sphalerlte, chalcopyrite, tetrahedrite, and arsenopyrite in a quartz and siderite gangue. Silver minerals, as such, appear to be lacking and silver values are no higher than in other sulphide ores of this type. These features contrast very markedly with those of the A.B.H. Consols Lode which appears to have emanated from the north end of the Broken Hill Main Lode Horizon during high grade regional metamorphism. The Consols Lode has been regarded as of Thackaringa type, and both are regarded as possibly arising from the remobilization of Main Lode Horizon ore. Whilst this may yet prove to be so it appears that the marked differences in mineral composition between the Consols and the Thackaringa types, would require somewhat different modes of regeneration.Thackaringa ore, as well as A.B.H. Consols ore, on this basis, would necessitate the development of a metahydrothermal ore fluid to account for their present apparently hydrothermal (or pseudo-hydrothermal) constitution...

Jan 1, 1967