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By Wang Y. J

This paper describes a more generalised or generic approach for the mine ventilation network problem. More specifically, it defines the network variables in a manner that establishes the network problem in a nonlinear programming format. Assigned to each branch are three variables: air quantity, regulator pressure loss and fan pressure. Each variable is imposed with lower and upper bounds. Based on these, the generalised network problem for a mine ventilation network with B branches is presented as a system of B independent network equations in 3B unknowns (variables) with variable bound restrictions, and it is classified as a nonlinear optimisation. A nonlinear programming model has been developed for this generalised network optimisation problem. The model is formulated and transformed into a standard equality-constrained nonlinear programming form with given variable bounds. Then, MINaS (Modular In-core for Nonlinear Optimisation System) is used to obtain solutions. Examples are given to illustrate this nonlinear programming approach to the mine ventilation optimisation problem.

Jan 1, 1993

By M Fimeri, R Williamson

Sample sizing in the iron ore industry requires significant manual effort to collect, transport, and sieve the samples as well as record, process and report the data. Efforts have been made to automate this process, which essentially emulate the manual process, except that a person is replaced by a robot. Even in these cells, the sieving and sizing operation consumes a significant proportion of robot time. The proposed doubling of production from AustraliaÆs iron ore mines over the next five years will place increasing pressure on sample sizing and interest is increasing in alternative automated methods. One such method is the adaptation of computer vision technology which has been successfully introduced into the mining industry in a range of applications including feed size distribution to SAG mills and oversize detection from screening stations. The limitation of this technology is that only the top surface is visible and this is used as an indicator of total size distribution. Obviously in a sample plant, where 100 per cent of the sample must be measured for acceptable quality assurance, this approach is unacceptable. In order to capture 100 per cent of the sample using computer vision technology a monolayer must be formed either by spreading the sample across a moving surface, such as a conveyor or vibrating platform, and passing this under a camera. This will become a æsurgingÆ load which presents specific problems for some types of computer vision systems, namely those relying on a 2D approach. In this paper a 3D computer vision technology will be described which overcomes the problems associated with measuring particle size in a monolayer and experimental results will be presented which demonstrate its effectiveness for lump and fine iron ore sample size measurement.

Jan 1, 2008

WHEN reading reports on reefs and lodes, one often comes across the statements "short shoot," "narrow shoot," "wide shoot," & c.From a number of reports in the writer's possession, some by members of the Geological survey, it is plain that the words "short," "narrow," "wide," "long;" &c., are used somewhat carelessly.In one official report on a certain field, for instance, the reefs are described as having "short, rich shoots"; another report on the same field states that "the reefs were characterized by narrow shoots, rich at the surface." Again, Charters Towers is described as having "wide shoots"; another writer says they are "long shoots. "The writer has read again of "short shoots which went down like pipes," and of "narrow shoots of limited extent." No doubt one can make out what is really meant, but the language is mixed. It is apparent that "narrow" is meaning the same as "short," and that the shoot has not much length in a horizontal direction. Nothing is said about the thickness or width of 'said shoot, or its depth. The "wide" shoot is evidently a "long" one; its thickness 01' width and depth is not specified. When we consider these terms, it is seen that only a few words are needed, and that these few should (as they do) have a definite meaning. In the course of his mining experience, the writer has seen shoots of almost all sizes, and some have been very long (in horizontal measurement), and have been followed down for great depths, these shoots being the best type-Charters Towers, Walhalla, &c., are examples.

Jan 1, 1909

The grade (or value) to volume relationship which constitutes a target orebody is used to show that the concentration of diamonds in an economic deposit may be as low as O.Olg/t. Diamond valuations from an Indonesian deposit demonstrate that the largest 5% of the diamonds in the deposit contributed 25% of the mass of diamonds recovered and 70% of the value from the ore. The need to consider the large stone content and the probability of recovery is used to estimate that the sampling density is required to be as high as 4-10,000ppm for a VLC deposit. This is compared with an acceptable sampling density for a bauxite deposit of 700ppb. A case history of the discovery of a diamond bearing paleo-channel in the Ellendale field in Western Australia illustrates that the sampling task becomes impractical. It requires an excavation in excess of 300,000 bcm of material to prove a 5M hem ore reserve. The conclusion is reached that setting up a small scale mining operation is an appropriate method of proving such an ore reserve and that the Code of Reporting should allow a category of "Mineable Resource" to cover such a situation.

Jan 1, 1990

Welcome to Mount Isa- my home city and without doubtthe base for what promises to be the most exciting mineral development yet seen in Australia.Mr. Chairman, it also gives me great pride to representthis area in the Queensland State Parliament as well as being the Minister for Minerals and Energy in the Queensland Government.Mount Isa is now part of the Australian mining industry folklore.It is all what a good mine is all about. It is. all what a good community is all about.

Jan 1, 1993

By Quan P. M

The great advances made in the application of solvent extraction to the recovery of copper from low grade ore sources over the past 15 to 20 years are well known. Solvent extraction is an essential step in the recovery and purification of copper from dilute sulphate leach solutions by which some one million tonnes of copper are now electrowon annually. A reagent is also available for the selective recovery of copper from chloride leach solutions and this may hold the key to the processing of complex sulphide ore concentrates. By comparison, the use of solvent extraction in the recovery and processing of zinc has as yet found little favour and is confined to only a few specific and comparatively small applications. This is despite the ready availability of a large number of low grade zinc sources and zinc-bearing wastes and residues. It is suggested that this difference is due in large part to the absence of suitable reagents having the particular features required to enable them to fit into a solvent extraction - electrowinning based process for zinc. Ideally, for the recovery of zinc from dilute sulphate solution, an extractant should operate on a proton exchange principle and be strong for zinc in the same way that o-hydroxyaryloxime reagents are strong towards copper. It should load efficiently with zinc at the pH of typical sulphate feed streams without the need for neutralisation and yet be stripped efficiently by spent zinc electrolyte. Another factor of major importance for many applications, however, is that it should be highly selective for zinc over ferric iron. These features have now been realised in a development extractant DS5846, which is a formulation of a novel class of reagent currently under investigation by Zeneca Specialties. The properties of this reagent are described with respect to selectivity, isotherms and how they compare with phosphoric and thiophosphoric acids that have been previously proposed for the extraction of zinc. For the recovery of zinc from concentrated chloride solutions a solvating or neutral donor type of extractant is required which again should ideally have high selectivity for zinc over a number of other metals, particularly iron. The new reagent Acorga ZNX50 is based on a formulation of a novel class of compound developed specifically for this purpose. It gives efficient extraction of zinc from feed solutions that are four to six molar in chloride ion but is readily stripped at 60 - 65¦C using either water, dilute brine, or spent zinc chloride electrolyte. The reagent is highly selective for zinc over iron and a range of other metals including cadmium, arsenic, lead and magnesium.

Jan 1, 1993

THE writer of this paper well realizes that the majority of engineering and metallurgieal works have from time to time evolved mechanical devices which are of great value as regards application in an operating plant.Many of these deviees would not be apparent to an individual making a brief inspection of works such as these, and it is for this reason that the writer proposes to outline a few of the devices which have been evolved by the engineering department of the Broken Hill Associated Smelters Pty. Ltd.NOVEL METHOD OF MACHINING A SPHERICAL JOINTFig. 1 represents one half of a casing for a ball-joint coupling. In the ordinary methods of boring an external spherical casing, that is with a radius bar attached to the tool rest of a lathe, there is always an error in the bore. It has two flat sides, and this error is inherent in the ordinary orthodox method and cannot be corrected. The engineers of the Broken Hill Associated Smelters Pty. Ltd. undertook a job that had to be extremely accurate, and the tool shown in Fig. 2 was evolved. The tool is not exactly fool proof, but in the hands of an average mechanic an absolutely perfect FIG. 1. sphere can be bored. The casing has to be held in the lathe in such a manner that one half can be removed without affecting the setting of the work. The business end of the tool is then placed inside the...

Jan 1, 1922

By R Nakia, R Livingstone

Historically the Goldfields of Victoria produced large volumes of gold. Interest in these historical Goldfields has grown over recent years with a view to restarting production of gold. A notable example of this is the Bendigo Goldfield. There is also interest in the Ballarat Goldfield and Ballarat Goldfields Ballarat East Project is a particular example of this. The aim of this paper is to describe the ventilation aspects of the potential Ballarat East project. The mine is proposed as a decline access. The paper gives an overview of the project and in particular the ventilation planning associated with a number of possible equipment scenarios. The paper also analyses the main ventilation pollutants that are likely within the proposed mine as it develops to increasing depth. An attempt is also made to determine the depth at which mine climate will become the dominant pollutant rather than diesel exhaust pollutants.

Jan 1, 2003

The authors have succeeded in providing additional rigour and clarity to the formulation and execution of the dynamic programming algorithm for optimum open pit limit determination. The inclusion of the blocks on the J + 1 column in the search for Pmax, and constraining this search with blocks assigned a value of negative infinity, ensures an optimal solution within the defmed blocks. The effect of the negative infmity blocks is to preclude mining along the diagonal blocks from the first row that they occur in. Figure 1 graphically illustrates the effects of this on the calculation of P. A practical application for constraining mining with negative infmity blocks is the case where the pit outline is defined by lease boundaries and not by the value of blocks to be removed. Any legal, social or physical constraint could be accounted for in the same way.The danger in applying this technique is that the negative infinity blocks will override any other more profitable solutions that may exist. This is in fact what has happened in the example that the authors use. If a further column is added to the left hand side (column -1) and the calculation is carried out again, a more optimal x-section can be found. (If the negative infinity values are removed the same result is obtained.) This gives a pit value of 112 as against the 108 of the authors' optimal pit. This calculation is shown in Figure 2. Lerchs-Grossman optimization is reliable only if there are sufficient columns available to allow "mining" to optimum depth of the ore body and still allow the pit to break out at the surface within the confines of the columns.This author's approach is to create enough columns each side of the lateral limits of the ore to allow the pit to intersect the surface while still within the confines of the block model. Implementing the methods discussed by the authors helps to reduce the number of columns required to achieve this.

Jan 1, 1987

By Hyde L. J

Blasting is one of the available technologies to be employed in underground excavation systems. In many instances it can be the only technology which is suitable. The recent moves towards more mechanised working systems is resulting in a reduced awareness of new blasting practices and technologies on the part of many excavation engineers. Recent developments in blasting systems can be utilised to significantly improve operating efficiency, reduce total cycle times, better comply with regional environmental constraints and reduce the total cost of underground excavation. Blasting is and will remain, a very adaptable and exciting alternative which is far from boring.

Jan 1, 1987

By L W. Palmer

"Evaluating the geological risk associated with ore deposits is becoming common practice in the mining industry. While geostatistical simulation is a useful tool for evaluating this risk, the effect of applying different types of simulation is less understood. For simulation of categorical variables like rock types, available methods perform simulation in fundamentally different ways. In this study, the geological risk relevant for informed mine planning is studied with two categorical simulation methods, PluriGaussian Simulation (PGS) and Sequential Indicator Simulation (SIS). Risk is expressed as a probability of repeated occurrence of lithological units in the same location across simulations. Significant differences are observed between the methods in terms of spatial distribution of risk. To identify the most plausible risk model, the input parameters at every step of both techniques are scrutinised. PGS and SIS inputs are classified as four parameters that are: fundamental to implementation of the methodfixed to enable comparison of PGS and SISdetermined by user interpretation, hence variablenormally optimised during application of PGS and SIS. The effect of parameter selection from categories 1 and 4 on the risk model is investigated using drill core data from a leucogranite deposit. A corresponding block model is created for assigning outputs from PGS and SIS. Risk models produced by either method are illustrated in a cut-out from the block model to enable bench-by-bench comparison. For PGS, risk associated with relatively rare lithologies is relatively sensitive to variation of parameters. Independent of the abundance of lithology, a location-dependent effect of variogram and vertical proportion curve parameter selection is observed, with risk increasing towards the deposit edge. Although SIS requires fewer inputs, single lithologies must be modelled in turn. Using small numbers of samples in the search neighbourhood, all risk models differ substantially. For larger numbers of samples, the risk models are similar. Overall it appears that the risk model produced using SIS is less sensitive to changes than PGS but further work is required to confirm this.CITATION:Palmer, L W and Glass, H J, 2014. Risk associated with rock type prediction using simulation techniques, in Proceedings Ninth International Mining Geology Conference 2014 , pp 217–228 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 18, 2014

Corrosion is a chemical or electro-chemical attack on a metal by the surrounding medium, and it can be stated in general terms that a non-corrodible metal possesses that property either because there is no chemical action between it and the medium, or because the medium reacts quickly with the metal to produce a thin protective coating.When iron or steel is attacked by dilute mineral acids, for example, the products of the reaction are soluble and the formation of a protective film cannot take place; on the other hand, rusting produces a porous film which flakes away and offers little protection to the underlying metal. However, when chromium is alloyed with iron, its resistance to corrosion is improved because the films produced on such alloys become more adherent and tenacious as the proportion of chromium is increased. Chromium is thus an essestial constituent of the corrosion- and heat-resisting steels.During the 40 years which have elapsed since their initial development, these alloys have made an important place for themselves in in<lustry and commerce, and it is the object of this paper to 'describe typical examples of the many types which are available; also, to give some indication of their particular properties, and applications in the mining industry.NOMENCLATUREVery few of the alloys which are about to be described can strictly be considered stainless, and most are not steels in the sense that they can he hardened by quenching from...

Jan 1, 1951

Diversification has characterised the mining industry in this country and globally in recent decades, and in Western Australia in particular. One of the most obvious aspects of diversification is technological change which continues at a rapid and sometimes bewildering pace. A function of technological advances is the increased capacity to further diversify the range of minerals which can be identified in economic concentrations and profitably extracted. This broadening of the total base of the industry has a synergistic effect on its further development by extending its geographical spread and increasing scope for decentralised infrastructure. Another aspect of diversification is the corporate thrust towards establishing overseas mining bases for a variety of reasons. Off-shore (sea bed) mining is a further manifestation of increasing diversity, although very much in its infancy.

Jan 1, 1996

There are a number a stages in a project at which an audit must, or should, be undertaken. An independent audit may be necessary for the comfort of directors and/or financiers before the major finance is committed, but an internal pre-development audit is the opportunity for the management team to take stock of the project and reaffirm their confidence and commitment. Maxims for project success are given and a check list for pre-development audits is presented. The need of mid-development audits may arise and their brief will depend on the circumstances arising. A game theory approach to decision-making is demonstrated in which the alternative of fast-tracking a development is considered. At the conclusion of the project, before the team is disbanded, a post-development audit should be made. Valuable learning can come from this process which could give important guidelines for future projects and a check list is presented.

Jan 1, 1997

Comalco's Bell Bay smelter produces some 94 000 t.p.a. of primary aluminium in the form of foundry alloys, extrusion billet and rolling blocks. The extrusion billet and rolling block are produced by a process, in which molten aluminium is poured into an open ended water cooled mould of the required shape. The bottom of the mould is initially closed off by a dummy or starting block. Primary cooling takes place at the mould wall and secondary cooling is achieved by direct water sprays onto the out side shell of the product. Careful preparation of the molten alumin- ium is essential if stringent alloy specific- ation limits are to be met. Optimum casting temperature must be maintained within a narrow range and metal cleanliness is important to ensure a consistent product. Increased demands of recent years for larger product and higher standards of surface quality and dimensional control have been instrumental in forcing improvements in furn- aces, casting machines and in mould and dummy Doq,

Jan 1, 1977

By M D. Raine, J K. Bartlett, S C. Dominy

The Bendigo Goldfield is located in the state of Victoria, Australia, and is one of a number of fields that make up the Central Victorian Goldfield. Since 1993, Bendigo Mining NL has been carrying out an extensive re-evaluation of the goldfield and is currently well advanced in developing an underground mine. The sediment-hosted auriferous quartz reefs are structurally complex and closely associated with anticlinal axes and reverse faulting. The gold within the quartz reefs is characterised by both its coarse nature (100 up to >5000 ¦m) and its erratic distribution; as a result, the Bendigo Goldfield is classed as an extreme nugget effect system. This characteristic ensures that the Bendigo mineralisation is very challenging to sample and evaluate. In this case, diamond drilling is a good measure of structure and geological continuity, but a poor measure of grade and grade distribution. Drilling, combined with on-reef development, bulk sampling and detailed geological studies are required for resource evaluation. For grade control a balance has to be sought between sample representativness, cost, turn around time and practicality. Extreme nugget effect deposits like Bendigo, require the use of bulk samples in order to be representative. However, the cost and turn around time is significant. As a result, a micro-bulk sampling system has been introduced that attempts to overcome these problems by providing a fast, practical method that can define ore from waste. Bulk sampling and on-vein development are still necessary for resource and reserve estimation.

Jan 1, 2003

This brief overview of the history of Brown Coal mining in Victoria is a luncheon presentation -I do not intend to make it indigestible with extensive listings of resources or production. There is a vast pantry of collated historical records and of vari- ous predictive studies available for the enquired with a hearty digestion. A gourmet collation is provided in The Aus IMM Monograph No 11 published in 1984 entitled "Victoria's Brown Coal-A HUGE FORTUNE IN CHANCERY", currently still on offer by the Institute and available at a bargain price in the foyer at this conference. Monograph No 11 also provides a feast of excellent references on the theme of Victorian Brown Coal assembled by the several contributors. In contrast, my presentation paper is a fast-food service, extracts from the printed paper only-you have no choice-you "get what you get" and in small quantity. I hope it will tantalise your appetite -like Oliver Twist you will ask for more. -Buy the Monograph!

Jan 1, 1989

Every estimate of ore reserves necessarily contains an assumption in regard to the specific gravity of the ore. This assumed figure may be based on experimental data, on textbook data, or on a reconciliation of past tonnage estimates and production figures. Not infrequently it is simply a guess - shrewd or otherwise.Errors in the density factor are not likely to be serious in gold-quartz mines-or, at least, not so serious as in base metal mines. It is to the closer determination of ore density in the latter that this paper is devoted. Moreover, the remarks apply to ores which show no appreciable pore space.Not many ore bodies are sufficiently homogeneous to allow of a truly representative factor being obtained by the simple testing of a few specimens of ore, or by the weighing, after breaking, of a carefully measured block. The empirical figure derived from a comparison of past ore reserves and actual production can never truly describe conditions other than those now past; no real link with ore as yet unmined is provided. The dilution of heavy ore by waste is not exposed by this method, but is effectively cloaked. Anyerrors in past estimations of ore reserves are transmitted, by way of the density factor, as a source of error in all future estimates.ObjectIons may be raised to the practice of weighing measured blocks of ore in the case of any but a very homogeneous ore body. Even then, the exact composition of the block weighed, and an indication of whether its moisture content is representative of the whole, are difficult to determine.

Jan 1, 1940

A blast is designed to completely break competent rock such that it can be economically extracted, and efficiently handled or processed. Efficient breakage of the rock is critical to the success of an operation, and in many operations blast design is optimised to achieve fragmentation, muckpile profiles, and material that is easily excavated. There are inevitably other issues, such as damage to adjacent rock, that should be taken into account when designing a blast to achieve overall optimisation. Some of the key issues with respect to the integrity of the in situ materials adjacent to a blast are identified and briefly discussed in this paper. The potential for damage and the effects of a blast will be strongly influenced by the rock mass properties. This makes it important that site specific conditions and their response to blasting are known. Practical techniques that allow the disturbance adjacent to a blast to be measured with minimum disturbance to operations are described in the paper. Experience shows that, during the blasting process, there is considerable potential to disturb the in situ rock mass adjacent to the blast. In some circumstances a very important objective must be to minimise disturbance outside of the immediate blast area. Measured and observed disturbances caused by blasting to adjacent rock, for various common types of blasting, are discussed in this paper. Blast induced disturbances to the rock mass have been observed in both the near and far fields. These disturbances have the potential to impact on geotechnical design. The geotechnical significance of blast disturbance on a rock mass that is to remain in situ is explored and suggestions with respect to design are given.

Jan 1, 2004

By G E. Holt

Active EM subsurface imaging is a proprietary technique developed by Marschall Acoustics Instruments Pty Limited (MAI) to image subsurface features at depths useful for the mining industry. Similar in field operations to high resolution seismic surveying, the Active EM technique employs electromagnetic energy rather than elastic wave energy. Received backscattered energy in the Active EM technique is thus due to differences and contrasts in electromagnetic permeability and permittivity in the subsurface, analogous to LamTÆs constants in elastic wave imaging. Carrying the analogy to seismic imaging even further, the Active EM method employs high power transmissions of very wide-band coded signals of a controlled polarisation. Likewise, the array pattern and polarisation of the receiving transducers is also tightly controlled. Thus, in a certain mathematical sense, Active EM is the electromagnetic equivalent of high power high resolution vibroseis seismic surveying. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008