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The ""multiple of exploration expenditure"" method of mineral valuation is applicable to exploration properties from the earliest stage of exploration to a moderately advanced stage but for which no resources have been delineated. While not recommended as a primary valuation method by some workers, others believe it to be the most satisfactory method of valuing exploration properties until it is possible to employ a DCF technique. In many situations facing the professional valuer, the method may represent the only semi-quantitative option available and is frequently used. Significantly it often forms the starting point in discussions to farm-in on an exploration tenement. The paper briefly reviews the definition of value as applied to mineral valuation and in particular examines the relationship between fair value and market clearing price in ""fair"", bull and bear markets. The multiple of exploration expenditure method uses previous exploration expenditure and/or future committed exploration expenditure to derive a base value for the tenements. This base value is multiplied by a prospectivity enhancement multiplier (PEM) with adjustments for market premium or discount and consideration of the quality of the exploration team to derive a fair value for the tenements. The paper will demonstrate that there is no necessary nexus between fair value derived from the method and present book Values.

Jan 1, 1994

By E Villaescusa

This paper summarises research work carried out at the Western Australian School of Mines on mine backfill properties in the last few years. The fill properties presented relate to cemented aggregate fill and cemented tailings fill. Emphasis of these studies has been placed on the composition of backfill materials including aggregate particle size distribution, cement dosage and influence of cement admixtures. The unique features of the backfill research carried out at WASM during the last few years are the accomplishment of a study into the properties of large cemented rockfill samples by triaxial testing and the investigation of the properties of fill material made from highly saline ground water prevailing in the Goldfields region of Western Australia. Exploring different cost-effective binding agents for mine backfill was also carried out at WASM. Special effort has been put on the development of fill materials compatible with hydraulic and paste fills. During the process, specific methods and procedures for laboratory testing of backfill material have been formalised. The on-going backfill research on sample scaling is summarised and the future direction of WASMÆs backfill research focus is outlined.

Jan 1, 2000

Carbonate replacement tin deposits in the areas studiedhere are genetically related to biotite granites. Biotite in the granites is distinguished by distinctive compositional features. High MgO content is found in biotite in the Renison Bell granite; high MnO and A1203 contents in the Gejiu granite; and high FeO content in the Xinlu granite. The compositional features of biotite in the granites are reflected in skarn minerals formed around the granites.Granites associated with these tin deposits are characterized by different accessory minerals. Magnetite-bearing granite in the Xinlu deposit is related to the andraditic garnet (andradite 40-45 mole%)-hedenbergite skarn, with tin mineralization occurring in the contact skarn only. The sphene-bearing granite in the Gejiu deposit is related to the grossular garnet (grossular 50-60 mole%, almandine 20-30 mole%) -salite skarn, with tin mineralization occurring in the contact skarn, as well as stratabound replacement orebodies in the distal skarn. The ilmenite-bearing granite in the Dachang deposit and the Renison Bell deposit is related to the grossular-diopside skam, with tin mineralization occurring 500-1500 metres vertically and 1.5-3 km horizontally away from the granite contact.

Jan 1, 1990

An efficient filtration plant can be designed only from an adequate knowledge of the filtration characteristics of the material to be handled; if these characteristics can be expressed in the form of an equation the work of design is simplified immensely. The literature of the subject contains numerous equations which have been developed by various workers to express their results, usually obtained from a 'Very limited class of material, and from moderately thick pulps. Such expressions have been found quite unsuited for use in the case of thin, very free filtering pulps.In 1926, Underwood put forward an equation having a general for m, and which, he was able to show, provided a satisfactory expression of the data obtained and published by a large number of earlier workers. This equation has been found a very satisfactory and useful tool for the study of a variety of filtration problems. As thel basis of the equation is of assistance to the understanding of subsequent discussion, a brief account of Underwood's derivation is given here.UNDERWOOD's FILTRATION FORMULAEThe following symbols are used:

Jan 1, 1932

Coal mining in the Illawarra commenced in 1848. By the early twentieth century mining operations were spread over quite a distance along the coast centred on Wollongong. By this time there were already numerous tunnel mines and one shaft mine. Coal was first reported in Illawarra by Lieutenant Flinders on a voyage of exploration, southerly along the coast from Sydney in 1796. Because of the topography, particularly the escarpment and the narrowness of the coastal plain, access from Sydney was not easy by land and the normal access was by sea. It was not until some coastal areas had been developed for agricultural purposes that the mining of the seams on the South Coast commenced for the supp- ly of fuel. The most important mines in the early nineteenth century were Bulli and Osborne Wallsend. In general, coal was won from the tunnel mines and was transported directly, usually by tramway, to the nearest shipping point. Considerable hardship attended the earliest attempts at mining coal in regard to materials for mining and the way of life of the miners in the vicinity of the mines. With the growth of production and the installation of coke ovens at some mines the area, hitherto virgin bush- land, began to take on a more industrialised appearance. The mines were necessarily small,

Jan 1, 1976

Most of the copper deposits in the Lachlan Geosyncline fall within areas having either a common host rock, mineral assemblage, form of ore body or time and method of emplace- ment. On this basis a Cobar-type ore has been recognised in the deposits of the Cobar -- Mt. Hope - Melrose region. The copper ores in the Tottenham-Girilambone area to the east have a different mineral assemblage. In the more rugged Central Highlands nearer the coast copper deposits are generally concentrated either in one of several Ordovician andesite belts, particularly between Wellington and Woodstock, or within Silurian acid volcanics developed in irregular fashion over a considerable portion of this region. In only a few instances is copper known in the granite batholiths which adjoin these volcanic belts. Native copper and magnetite are characteristic of the deposits of the andesite province and it is possible that future mineragraphic studies will indicate significant differences in the base metal sulphides of both the andesitic and the more acid volcanic belts. Ores having similar mineralogy and form to the Captain's Flat deposit are known at various localities in the eastern segment of the latter belt. In the Gundagai area several small copper deposits with associated nickel minerals have been developed in the Coolac Serpentinite belt.

Jan 1, 1969

By E M. Rykaart

The design of soil covers as part of the remediation initiatives for mine waste facilities is common practice and more and more engineers are faced with designing these facilities. The design issues associated with these soil covers are complex and requires a good understanding of unsaturated flow. More engineers are making use of numerical models to predict how cover designs would perform, and this has been necessitated by the high non-linearity associated with solving unsaturated flow problems. There are numerous numerical models available to the prospective users and they are all simplifications of reality using different assumptions. The users of these models often do not understand the limitations of the models but rather select a model based on ease of use, and that lends to increasingly erroneous designs being proposed for construction. This paper describes a comparative evaluation of a cover design using four different codes available today; SoilCover, SWIM, HYDRUS-2D and HELP. The paper does not propose to measure these codes up against each other and make statements about which is better than the other but rather illustrates how the assumptions in each code affect the outcome. The data set used for the comparative study is a well calibrated data set that that has been collected over a long period in time and that has been collected according to strict controls. The authors present the pitfalls of numerical modelling of the surface flux boundary conditions, as well as present guidelines towards appropriate use of these modelling tools.

Jan 1, 2003

By P Walton, L W. Armstrong, D P. Blair

Sydney is the capital city of NSW and has a population of approximately four million people. Eighty per cent of the cityÆs water is supplied by Warragamba Dam, which is situated some 75 kilometres south west of the city centre. A risk assessment was carried out on the dam and future predictions of water flows into the catchment area showed that there was a risk of a one in 700-year flood not being contained by the dam. The predicted loss of life and property damage warranted the construction of an auxiliary spillway on the eastern side of the existing dam to cater for any uncontrollable influx of water. A test blasting program was instigated and the blasting parameters were established that would lead to routine production blasting of the sandstone rock making it more cost effective to excavate. Blast induced vibrations were a concern to the owners and the dam wall and ancillary infrastructure was instrumented with sensitive vibration monitoring equipment during the test blasting phase of the operation. Once the blasting parameters were established from the testing program production blasting was carried out on a daily basis to maintain æstockpileÆ of fragmented ground for the excavation equipment. Blast vibration models were developed to predict vibration levels for more sensitive areas of the dam to give the operators more confidence in their operations. The blast induced vibration levels recorded did not cause any structural damage to the dam wall and the waveform frequencies of the blasting operation were much higher than that experienced during a recent earthquake. The integrity of the SCAÆs assets were at no time jeopardised.

Jan 1, 2001

Titanium dioxide (TiG ) is produced 2 commercially by two methods generally referred to as the "sulfate" route and the "chloride" route. The SCM Corporation, in supplying 15% of the world's demand for TiO 2, uses both of these processes. Of the two processes the sulfate route is generally regarded as the older and more established technology. Worldwide the sulfate route accounts for some 70% of total Ti02 production. However, in the U.S.A. the chloride process accounts for 80% of production. The processes vary in chemistry and raw material requirements. In the "sulfate" process finely ground ilmenite or titanium slag is digested with sulfuric acid to produce a porous "cake" vrnich is extracted with water and recovered liquor. The solution is treated with scrap iron to reduce any ferric ions to the ferrous state which is then crystallised and removed as ferrous sulfate heptahydrate. The liquor is concentrated by evaporation and hydrolysed to form the insoluble hydroxide which is filtered and washed free of impurities. This is converted to the dioxide by calcination at 800 - 1000¦C and milled to break up any aggregates. The "chloride" process uses a higher quality feedstock of natural or synthetic rutile and/or high grade titania slag. The feedstock is mixed with ground high-purity coke and chlorinated at 950¦C in a fluidised bed. The resulting crude titanium tetrachloride is purified by distillation and chemical treatment. The purified titanium tetrachloride is burned with oxygen or oxygen enriched air to give titanium dioxide and chlorine, which is recovered and recycled to chlorination. Titanium dioxide pigment from both processing routes undergoes similar finishing techniques. It is subjected to further stages of wet and dry milling, then coated with layers of inorganic oxides in order to enhance its properties for specialist applications.

Jan 1, 1986

Prospecting in arid terrain can produce substantial environmental impacts, comparable to or greater in magnitude than the impacts associated with actual mining or petroleum production. Impacts are likely to be particularly severe where prospecting involves intensive geophysical exploration, especially in areas which have escaped degradation by other land uses such as pastoralism. With appropriate environmental planning and management, however, the environmental impacts of prospecting in arid terrain can be greatly reduced and mitigated, at low cost. In many countries, prospecting licences, exploration leases and associated tenements now carry a range of conditions relating to environmental protection. The assessment, avoidance and mitigation of environmental impacts is therefore an important component of and-zone exploration. My aim here is to give an overview of some of the main aspects of an environmental planning and management (EPM) programme for prospecting in arid terrain (PAT). Detailed operational prescriptions for environmental protection procedures are necessarily specific to particular areas and types of prospecting: see. e.g., Buckley (1982a, 1984, 1985a, 1986a), Klepacki et al. (1985) and Stone (1986). The intention here is to provide a checklist rather than a recipe book: as an aid in incorporating environmental aspects into the overall planning and management of an exploration programme, and in liaison with company environmental staff, consultants and regulatory bodies. I also hope to show that whilst some of the techniques used in particular environmental disciplines certainly require specialist expertise, the overall design of an EPM programme is not in the least esoteric, but simply an exercise in straightforward common sense. Perhaps this paper could be subtitled: "Demystifying environmental Planning".

Jan 1, 1988

Mid-ocean ridges host approximately 65 per cent of about 100 known sites of high-temperature venting and polymetallic sulfide deposits; most of them are located at the East Pacific Rise (EPR), while more diverse mineralisation styles occur at the Mid-Atlantic Rise (MAR). Seafloor hydrothermal activity at the EPR are related to MORB while different substrates, including MORB and ultramafic intrusive rocks, are associated with æblack smokersÆ at the MAR. Depth of hydrothermal activity ranges from 0.7 to 4.3 km. High-temperature vents precipitating Cu-Fe sulfides (chalcopyrite and isocubanite, rare bornite), pyrrhotite, pyrite (¦ marcasite), and sphalerite, and low-temperature edifices precipitating marcasite (with pyrite), sphalerite, barite, andsubordinate chalcopyrite (pyrrhotite and isocubanite are absent) occur in both environments. There are considerable differences in Fe, Zn, Cu, Ag, Au and trace element contents in ores and in theFeS contents in Zn-sulfides in these deposits. Acomparison with anhydrite and sulfide minerals precipitating from modern black smoker fluids sulfide reveals many similarities but also some important differences. Fluids with salinity values above and below that of seawater at 400¦C down to 130 - 170¦C deposited sulfide minerals. Mantle-derived He prevails in fluids trapped by sulfides in EPR 9¦N and 21¦N hydrothermal systems. Hydrothermal fluids in MAR and back-arc systems are richer in radiogenic 4He. The sulfur isotope composition varies in the different hydrothermal fields and within zones of a chimney. EPR sulfides display narrower range of d34S values, while MAR and back-arc sulfides can bedepleted and enriched in the heavier d34S isotope. The most important finding is that fluid temperature, salinity, R/Ra ratios and d34S values ranged more significantly in the polymetallic sulfide deposits than when measured directly on venting fluids. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

Evidence for Middle-Late Triassic large-scale, silicic volcanism characteristic of extensional continental terranes is widespread in the Tasman Orogenic Zone in Eastern Australia. Detailed study of an area of south-east Queensland has defined the eroded remnants of a large collapse caldera and an associated area of rhyolite dome building and regional downsag which may be a second caldera (Stephens, 1986). The silicic volcanics and minor basaltic to andesitic products have been assigned to the Aranbanga Volcanic Group (Cranfield, in prep.) and the associated granite complex has been named the Mungore Complex (Ellis, 1968). Published isotopic age dates on the Mungore Complex are 212-219 m.y. (K-Ar Biotite; Ellis, 1968) and 226 m.y. (pooled Rb-Sr on several similar plutons in the region; Webb and McDougall, 1967). Basalts within the area have been dated at 219 m.y. (GSQ Annual Rpt., 1986). The collapse caldera (Mungore Caldera) lies on the intersection of 4 major structural features: 1) the Mt. Perry Lineament, a meridional fault zone extending for over 600 kilometres in a NNW-SSE direction and which has faulted the eastern part of the caldera 5 kilometres sinistrally. The lineament has been active at least from mid-Permian to Late Triassic and has localised activity into the Tertiary. Granite plutons of the same age as'the Mungore Complex- are topographically prominent and largely concentrated east of the Mt. Perry Lineament and its extensions (Nash, 1986); 2) the extension of the Darling River Lineament, a continental-scale, ENE trending feature which correlates with regional structural discontinuities but which lacks expression as faults within the Tasman Orogenic Zone;

Jan 1, 1987

By N Kreutzman, A Moilanen, V Palosaari

Carboxymethyl cellulose, CMC, is widely used in mineral processing as a flotation depressant, mainly for the depression of carbonate and talcaceous gangue in the flotation of Cu-Ni sulfide and PGM ores. Although CMC is a common depressant that can be used in the flotation of different ores, understanding of the interaction mechanisms between CMC and mineral particles in different flotation circuits and different pulp conditions is still limited. Electrokinetic measurements, microflotation and laboratory-scale flotation tests were carried out to optimise the action of CMC depressants in the flotation of a PGM ore. Standard and new CMC brands produced and characterised by Noviant were used in the study. Pure talc and chlorite minerals and a low-grade PGM ore composite were used as test materials. A laboratory flotation test evaluation was performed using the recovery-grade relationship and double value index (DVI) calculation to estimate the effects of both valuable and harmful components on the product value. Solution conditions play an important role in the depression of gangue minerals such as talc. The most favourable conditions for MgO depression were found to be mildly acidic in which conditions the electrostatic repulsion between the CMC molecule and talc is minimised. Similar effects were obtained with electrolytes that affect the conformation of the CMC molecule and the mineral surfaces. In addition to the control of chemical conditions in the pulp, CMC molecules were modified to optimise structural variables. The new CMC brands developed in this work showed significant potential to improve flotation performance, particularly when pulp conditions are controlled.

Jan 1, 2005

By J J. Cilliers, E Ventura-Medina

Mineral froth flotation is used to separate particles of valuable mineral from its associated gangue. It involves the selective separation of the hydrophobic particles from the slurry into the froth. As air is blown into the slurry, the hydrophobic particles attach to the air bubbles, while the waste particles remain in suspension. While the froth rises up, bubbles start to coalesce and burst, allowing the entrained liquid surrounding the bubbles to drain and return part of the gangue to the pulp. Mineral separation is therefore a function of the amount of valuable material loaded on the bubble shells, as well as the amount of gangue material entrained in the liquid channels separating the bubbles (Plateau borders). As a result, the separation performance of the process is affected by mineral attachment and drainage or bursting in the froth. This study aims to establish the relationship between solids loading, froth stability and separation performance. For this purpose, a series of industrial experiments were carried out to measure mineral attachment as well as bubble bursting by combining direct sampling of the bubble films and video image analysis of the froth surface. This work suggests that the solids loading on bubbles strongly affects the separation performance. The results generally showed that solids loading and concentrate grade are closely related, while froth bursting rate can be linked to the drainage of gangue from the Plateau borders and also to the overall recovery of valuable mineral. It was shown in particular that higher loadings, usually associated with higher froth bursting rates, are indicative of more selectivity in attachment and therefore a higher mineral grade in the concentrate. Additionally, this work suggests that bubble solids loading and froth stability are essential parameters to include in froth flotation models as they allow control and optimisation of the flotation performance.

Jan 1, 2005

Water is an integral and essential part of mining business. Two issues crucial in the management of this resource, scarcity and excess, are increasing awareness of the importance of water and changing the value perceptions of the industry because they affect both the existence and continuation of the business. Therefore its value should be reflected in the water management that is practised on site. Historically water in mining has been perceived to be of low value so management practices have not been good or well implemented. Political and social transformation in South Africa has been accompanied by the promulgation of new legislation. South African water law is now underpinned by Integrated Water Resource Management (IWRM) principles. It impacts water pricing, provides for water pollution charges, prioritises water users, has specific mining and water related components and requires water licensing as part of the licence to mine. Mining no longer has a priority on water resources and has to compete with other water users to gain access to resources. New institutional arrangements are being put in place to implement the regulations. All this requires a paradigm shift in miningÆs view of water. Generally the sector is still catching up with the new requirements, principles and philosophies. However, the way in which South African mining values water is changing. This is demonstrated in partnerships between the industry and other water users. These partnerships are Integrated Water Resource Management (IWRM) in practice and they achieve sustainable development goals. These partnerships are essential for mining to stay in business, expand operational capacity, reduce impacts, prevent legal action and reduce reputational risks.

Jan 1, 2006

By C P. Kramers

The need to provide a sufficient quality and quantity of backfill continues to increase in South Africa, particularly as related to the increasing depth of mining. More and more applications require well designed fill systems either as classified or cemented backfill, and in some applications even tailings/aggregate based backfills. The paper discusses developments in backfill technology in South Africa with special emphasis on reliable system designs and operations, particularly as related to the preparation and hydraulic transportation aspects. Approaches for the alleviation of previous problems associated with premature pipe failures in vertical shaft columns for the distribution of tailings based backfills are discussed. Resulting from CSIRÆs developmental work, reliable full-flow systems, which can operate at low system pressures, have become a common practice, provided that backfill flowrates and internal pipe sizes are well matched. This aspect is reviewed. With regard to the tailings/aggregate based backfills the paper reviews some of the results of comprehensive in situ monitoring and the development of such systems. It is shown that a thorough understanding of the effects of aggregate top size, fines content and slurry relative density is required in order to ensure the restartability of temporarily shut-down pipelines. Some innovative technologies for the comminution of development waste underground to yield aggregate products potentially suitable or hydraulic transportation and backfilling, are briefly discussed.

Jan 1, 1998

Mining projects draw together stakeholders with various degrees of experience in managing and assessing financial risk. When this risk is not fully appreciated or quantified, the potential for making decisions not suited to investor requirements is significantly increased. A feasibility study provides key information on project development potential, requiring detailed technical investigations with thorough financial analysis. Centaur Mining and Exploration (CME) owned and operated Cawse Nickel Operations (CNO), one of three Australian projects to develop and process vast amounts of near surface nickel resources. A technical ædue-diligenceÆ and æbankable feasibility studyÆ confirmed the large resource base, newly applied yet tested technology and relatively low unit costs would produce nickel in the lower half of industry operating costs. A number of production variables including capital requirements, delayed start-up, nickel grade, processing, maintenance and product output were outside the feasibility estimate. This was combined with exchange rate fluctuations and lower Ni prices. The inability to generate adequate cash flow and service debt repayments ultimately led to receivership and liquidation of all assets. Following the sale of CentaurÆs gold and nickel divisions, $A 784 million remained outstanding to creditors. This paper aims to define key issues leading to CNOÆs collapse by reviewing feasibility parameters, valuation methodology and project development. Some methods of assessing project viability are discussed with the aim of increasing stakeholder risk awareness.

Jan 1, 2003

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

By D E. Langberg, J S. J va, D R. Swinbourne

Specifications on the types and levels of impurities tolerable in metals are becoming increasingly stringent, and are pushing the limits achievable with conventional refining technologies. Particularly difficult is the removal of electrochemically noble elements with low volatilities, such as copper, from more active host metals such as lead, iron and aluminium. Electrochemical refining, utilising the ability of certain solid electrolytes to selectively transport copper or other impurity cations away from the molten host metal into a separate refining phase, may provide an answer to this problem. Numerous studies on solid electrolytes used in concentration sensors have been reported, as well as a limited number on metal refining. Oxygen anion conducting solid electrolytes have been applied to the deoxidation of copper and steel while cation conductors, eg ¯ -alumina and Nasicon materials, have been used to remove lithium and sodium from aluminium. However, solid electrolytes have yet to be applied to the removal of noble elements. The behaviour of solid electrolytes under the extreme conditions of molten metal refining is not well understood. This paper will examine the potential use of solid electrolytes to remove noble metals such as copper from active host metals such as iron. The suitability, and selection criteria of available solid electrolytes for implementation in the metal refining industry in the future will be discussed. In particular, the stability of Cusicon, a copper superionic conductor potentially suitable for use in metal refining, has been assessed and the results of the experiments are presented.

Jan 1, 2000

The mining industry provides employment opportunities for individuals from a wide variety of disciplines. Solid Energy New Zealand Limited (Solid Energy) is New ZealandÆs largest coal mining company and the career opportunities for school leaver trainees and university graduates are numerous. Solid Energy also provides fixed term opportunities for consultants and contracting companies, who complement the wealth of knowledge already within the company.   Focussing on Stockton Mine and my involvement there as an Engineering Geologist, this paper looks at Stockton Mine and the Stockton Water Management Project and outlines the career paths of other young professionals also working at Stockton.

Jan 1, 2007