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By M A. Gontalves, A F. D C Varajpo

The Rio Capim kaolin district, located in the north-east of Parß State, Brazil, constitutes one of the worldÆs largest high-whiteness kaolin reserves for the paper coating industry. It contains, at the base of the main ore, a soft kaolin that gradually changes at the top into a ferruginous duricrust followed by a flint kaolin. The flint kaolin is completely discarded during the exploitation of the soft kaolin. With the view of a more complete beneficiation, aiming at a sustainable development of the minerals industry, the use of this residual flint kaolin has been considered for the manufacturing of zeolites. Zeolites were synthesised from the flint kaolin through a reaction between metakaolinite with soda at 80¦C, for durations of 24 to 144 hours. The transformation into metakaolinite was carried out at 800¦C and was not affected by the titanium oxides. For a synthesis time of only 24 hours, a zeolite 4A very close to its theoretical definition was obtained, whereas for synthesis times longer than 96 hours, a slight formation of hydro-sodalite was also observed. The synthesised zeolites were tested as cationic adsorbents on 0.5 molar solutions of Cu, Pb, Cd and Zn. The adsorption was measured for contact durations of one and three days. It was noted that the exchange kinetics were slow and that the retention was significantly greater after three days than after one day. The retention was greater than 50 per cent of the theoretical exchange capacity for Pb, Cd and Zn, which was different to Cu, where the retention exceeded its theoretical exchange capacity.

Jan 1, 2008

The Permian coal in the Muja Coal Measures of Collie Basin of Western Australia has a subdued lustre because of the fine laminations of lithotypes, and the dominance of dull and dull banded lithotypes with minor bright, bright banded and fusinous types. The maceral composition of the coal is variable, however the macerals of vitrinite and inertinite groups dominate and the exinite and mineral matter contents are low. The lithotypes have low concentrations of trace elements and the boron concentration is between 10 - 100 ppm recorded only from the dull lithotypes. On the basis of organic petrology, the inter-seam sediments, flora and the very low concentration of boron, the depositional environment postulated for the coal is braided, fluvial and fluvio-lacustrine with marked fluctuations in the water table. The low water table in the environment accounts for fusain and inertodetrinite in the coal.

Jan 1, 1996

The methods used by the Anglo American Corporation for analysis of long-term metal markets and prices are described. The principal factors affecting the relationships between production costs and metal prices are analysed. These are firstly the type of market, - speculative or consumer commodity, free market or subject to price control; and secondly the rate of growth of demand for the metal. It is shown that virtually all metals will have relatively low rates of demand growth for the foreseeable future, due to market saturation, increased economisation, substitution and product obsolescence. Metal prices have a clear dependance on production costs, however forecasting future costs is by no means simple; amongst other things, account must be taken of changing exchange rates, inflation rates, and the potential for operating more efficiently. The paper concludes by giving brief assessments of the long-term future for aluminium, copper, zinc, nickel and tin.

Jan 1, 1986

By Lyman G. J

The volumetric distribution of valuable mineral, or phase, within a set of particles is called the liberation distribution. To optimise a mineral processing plant it is necessary to know the liberation distribution in most of the streams, especially those adjacent to separation devices. Possibly the most common method of analysing ore particles is to section sets of similarly-sized particles. However, the observed sections can appear liberated even if the particle is composite. This means that the 'apparent' liberation distribution can be very different to the 'actual' liberation distribution. This discrepancy is called stereological error. One must then somehow estimate the actual liberation distribution using the apparent liberation distribution. This problem is called the liberation distribution problem and its solution is the subject of this paper. The solution is based on a sorting algorithm which uses geometric probability equations. These equations are based on the assumption that sectioning is isotropic and uniform. Apart from these assumptions the equations are completely independent of particle shape or texture. The algorithm is verified by numerical simulation and experimental methods. For the numerical simulations the correspondence between the actual and estimated liberation distributions is excellent. For the experimental methods, the agreement is not as good and appears to be due to experimental errors.

Jan 1, 1995

By Paterson M. R, Spencer P. A

Vitrokele technology is a resin process that can be applied in gold plants to reduce both capital and operating costs. The Vitrokele resin can be used for both precious metal recovery and for recovering free and combined cyanide from effluent streams. Vitrokele resin has been extensively tested at pilot plant level and is now applied successfully at a commercial heap leach facility in Zimbabwe where it is used in place of activated carbon for recovery of gold from pregnant leach solution. Significant capital cost savings were achieved by installation of a resin plant instead of a conventional carbon adsorption plant. Operation to-date has not seen any significant physical or chemical degradation of the resin either in terms of adsorption capacity/kinetics or physical appearance/size. This gold recovery process is equally applicable to slurry streams where it would be implemented in stirred tanks with interstage screens in a similar manner to a conventional carbon adsorption plant.

Jan 1, 1996

By D Craw

Middle and Late Cenozoic fluvial conglomerates and gravel in northeastern Southland record the transport of alluvial gold from Central Otago into Southland, and subsequent reworking and concentration of this gold into economic placer deposits. A corridor of geochemically distinctive, Hg-free gold derived ultimately from veins in Torlesse Terrane schist in Otago extends through the Caples Terrane and into Southland. The initial repository in Southland was fluvial sediment of the East Southland Group, specifically weakly auriferous, quartzose delta plain strata of the Gore Lignite Measures (GLM), a downstream equivalent of Dunstan Formation in Central Otago. Miocene uplift along the northwest trending Old Man Range beheaded the parent river system, isolating GLM from its Central Otago source area and establishing the proto-Waikaia River system. Rising topography between Otago and Southland increased fluvial gradients, and initiated erosion of cover strata and a sequence of tectonically induced gold recycling events. Auriferous GLM were recycled from the hinterland into broad braided fluvial channel and floodplain deposits of the Waikaia Group (new), specifically the highly auriferous Waikaka Quartz Gravels and equivalent Waimumu Quartz Gravels downstream (WQG), superimposing more proximal depositional environments over parts of the former GLM delta plain. WQG were deformed, and locally cannibalised during the later stages of their deposition by reverse movement on north-northeast trending faults of the Dunsdale System (NW side up). Increased tempo of uplift in the hinterland (Old Man, Garvie, Umbrella, and Blue Mountain Ranges) in the Pliocene and early Quaternary resulted in further reworking of GLM and WkQG from the hinterland as well as basement erosion. Progressively more basement-rich detritus was deposited as a locally auriferous piedmont (Gore Piedmont Gravels - GPG) over earlier channel and delta plain (GLM, WQG) strata, extending from the Blue Mountains to Waikaia, and southward through the Gore Gap to beyond Mataura. Southward propagation of the north-northeast trending ranges, local warping, and uplift of the Murihiku Terrane in Pliocene and Quaternary progressively deflected GPG fluvial systems and ultimately constrained them to the present valleys. Pre-existing auriferous strata (GLM, WQG, GPG) were reworked and deposited with or without basement detritus as these fluvial systems migrated toward their present positions. Auriferous remnants of these transitional deposits are preserved in local structural depressions on the uplifted blocks that deflected the systems (eg King Solomon Mine), and on locally abandoned floodplain segments on the lowlands (Pebbly Hills-Gore Gap). The present drainage has continued to incise and cannibalise its own and earlier deposits during late Pleistocene-Recent uplift to form confined channel placers within the present valleys.

Jan 1, 2002

By Propster M, Choudhry M

THIS note gives comments on the paper by Kitaev et al on p. 68 of this book and compares results with those obtained by ourselves. We wish to say that the authors are to be congratulated on their sophisticated approach to an important problem and that it complements our efforts on flow maldistribution.1-5 It is our view that Eqs. (1)-(5) on p. 69 are impressive, but unfortunately with present day computers and computational facilities, it would be quite impractical to contemplate the numerical solution of these. Eq. (8) in the authors' paper, on p. 70, does provide the logical starting point for tackling flow maldistribution problems and strictly speaking this equation is more accurate than Eq. (1) in our paper in this book. We note in passing that there is direct experimental evidence to support the contention that our Eq. (1) is at least a reasonable approximation and one may question in a practical sense whether the refinement afforded by Eq. (8) in the paper by Kitaev et a/ is justified. While one must readily accept the appropriateness of Eq. (8) of Kitaev et al as a starting point, the subsequent mathematical manipulation by the authors is open to serious criticism. In order to solve this complex, non-linear equation Kitaev et al postulated irrotational flow, which afforded considerable simplification. One can argue simply on physical grounds that the assumption of irrotational flow is inappropriate, a fact which should be readily apparent on inspection of the flow fields shown in Figs. 2 and 3 of Kitaev's paper. It follows that while the starting point through the use of Eq. (8) is correct the results derived from this starting point may be suspect because of the erroneous nature of the irrotational flow assumption.

Jan 1, 1975

By Langham B. M

A chemical study of the petrographic components of Greta (Maitland) coal, carried out by the Metropolitan Gas Co. (Melbourne), has revealed an anomaly in the composition of the durain which was thought to warrant petrological investigation.The original study, by the Metropolitan Gas Co., extended over eight shipments of coal received during the winter of 1943.The percentages of the several petrographic components were eslimated by careful handpicking of large samples of each shipment, and analyses were made of the handpicked components, which were also tested as to their gas-making and coking properties.The results are summarised in Tables 1 and 2. At first sight the components of the Greta coal bear a general resemblance in composition to those of other bituminous coals of similar rank, apart from a notable richness in volatiles, which is a distinctive feature of Greta coal. The durain has a typically higher ash content, and lower volatile content than the clarain (Table 1); and the coking behaviour of the four components is typical (Fig. 4).When, however, the analyses of Table 1 are re-calculated on a dry, ash-free basis, an anomaly appears: the clarain and the durain, on this 'pure coal' basis, have practically identical compositions, with the durain containing a slightly higher proportion of volatiles than the clarain (cf. Table 3); but the tar yield of these two components is very different (Table 1). Re-calculated on a dry, ash-free basis, the yield from the clarain is 18.9 gallons of tar per ton, while, that of the durain is 29.0 gallons per ton. The gas derived from the durain is correspondingly richer in illuminants (CH etc) and poorer in hydrogen than that from the clarain (Table 2), and is also notably richer in nitrogen.That the composition of the Greta durain is consistent is proved by the analyses of Table 3, in which the compositions of the respective durains and clarains of eight separate shipments of coal are compared. In most bituminous coals, the durain contains several per cent less volatile matter than the associated clarain, and high volatile content in a durain usually indicates a durain rich in spores.

Jan 1, 1947

With mining development on hold and other underground works in a slowdown, the develop- ment of nuclear waste repositories takes center stage on the American rock engineering scene. Three repositories for commercial spent fuel -- in salt, tuff, and basalt -- are in the phase of site characterization and conceptual design, and one pilot project for defense high-level waste in salt is under construction. A repository design for crystal line rock has recently been postponed. Because of strict quality assurance requirements throughout design and construc- tion, and because of the need to predict and ascertain in advance the satisfactory perfor- mance of the underground openings, much intellectual energy has been expended to analyze underground openings in the unusual circumstances of the repository environment. In the long term, these efforts will lead to an improved understanding of rock behavior and improved methods of underground analysis and design. For the shorter term, a formalized ground control plan was developed, the princi- ples of which may be applied to other types of projects. This paper summarizes the status of underground design and construction for nuclear waste repositories and presents some details of the ground control plan and its individual elements.

Jan 1, 1987

Valuers will often intuitively express the probability that property value will exceed a certain amount . . . 'I think the chances that the value will exceed $50 million are excellent. The chances that they will exceed $80 million are poor'. This paper shows how it is possible to combine the uncertainties of the value of several key items to provide an estimate of the probability of a certain overall value being achieved. The valuation of a large copper/gold deposit was naturally influenced by uncertainties in the base assumptions of costs and metal prices. Potential acquisition of the property through share purchase raised the issue of what was a reasonable intrinsic value for the shares. Market considerations could be used to appropriately adjust the intrinsic value. After a range of possible metal prices and operating costs were determined, estimates were made of their probable distributions. By combining these probabilities in a random selection, a range of property values was calculated. Each value had its respective probability of occurrence. This allowed a most likely value of shares to be calculated. This paper demonstrates how the valuer's intuition is complemented by numerical analysis.

Jan 1, 1994

It would be a good thing when reviewing the challenges to be faced by the Australian gold industry to set the backdrop and scene for them, by briefly examining the history of this vital and dynamic industry in the Australian context. Gold mining in Australia had its official beginnings in 1851 when John Lister and William Tom discovered gold at YorkyÆs Corner, later renamed Ophir by Edward Hargraves. From that first tentative beginning, the ensuing rush of prospectors into New South Wales and Victoria meant that the annual gold production in those early years surpassed that of the next 40 years. This early rate of production was only eclipsed when AustraliaÆs production was once again lifted by the discovery of gold on the other side of the continent, in Western Australia. (Figure 1). The years leading up to the First World War saw Australian production peaking once again at over 115 tonnes of gold, a production rate that would not be surpassed until 1988. This renaissance in production at the beginning of the 1980s was achieved by the application of technology. The advent of bigger trucks and shovels meant that earth-moving costs dropped dramatically. This, coupled with the highly effective and efficient carbon-in-pulp processing route, stimulated the Australian gold mining industry into a state of frenetic activity. These two innovations were the principal factors that enabled the economic exploitation of the lower grade haloes left by the æold-timersÆ around the deposits exploited at the beginning of the last century-no high finding costs here. AustraliaÆs production through the 1980s and the early part of the 1990s was largely supported by the exploitation of these haloes. As these were depleted, the aggressive exploration effort stimulated by the strong cashflows of these early oxide deposits resulted in new æblindÆ discoveries which are now emerging as the backbone of the Australian industry (Figure 2). Gold production is a major contributor to the Australian economy. In 1998/99 the Australian gold industry accounted for approximately 16 per cent of the value of all mineral exports, which in turn accounted for over 35 per cent of AustraliaÆs total exports. As such, the Australian gold industry, by itself, accounts for just under six per cent of AustraliaÆs total exports (Figure 3). Consequently, the industry is responsible for over one per cent of AustraliaÆs gross domestic product. These statistics are all the more compelling when we consider that, at the beginning of the 1980s, goldÆs contribution to exports and GDP was insignificant (Figure 4). Within the Australian resources industry, gold mines and associated infrastructure account for ten per cent of all capital expenditure (Figure 5). From an employment point of view, in 1997/1998 the industry directly employed (excluding contractors) about 7700 people, approximately 15 per cent of all those employed in the minerals industry. Just under nine per cent of the workforce in the minerals industry are female, whereas in the gold industry over 16 per cent are female.

Jan 1, 2000

By Gleadow AJW, Foster DA, Kohn BP, Raza A

A large and increasing data base of apatite fission track results from sedimentary and granitic rocks exposed within the southeastern highlands and along the continental margin of Australia provides constraints for the tectonic development of the southeastern passive margin. The fission track results suggest that many regions of the southeastern margin of Australia experienced distinct episodes of relatively rapid cooling during the middle Cretaceous to early Tertiary that can be attributed to the effects of rifting. One cooling episode is middle Cretaceous in age and related to denudation of the southeastern highlands from Tasmania to northern New South Wales between -90-100 Ma. Rocks exposed along the present coast line record a later episode of rapid cooling, which is diachronous and decreases in age northward from -80 to 90 Ma in northern Tasmania to southern New South Wales, -60-80 Ma in central and northern New South Wales, and to -50-60 Ma in southern Queensland.

Jan 1, 1995

Brief summary of results obtained by a French-Japanese cooperative study on the bottom of trenches around Japan. The geophysical prospection, multi beam echo sounding and direct observation with submersible dives of the trench bottom clarified the details of the subduction of oceanic plates. It may be noted, among many new facts found: 1. The subduction and geologic structure resulted from the process is different according to the nature of subducting oceanic plate, and the geology of the land behind the trench. Thus the Nankai trough characterized by the developpement of accretionary prisms is contrasted to that of the Japan Trench where the basement rocks are exposed on the land side cliff of the trench wall. 2. The compressional tectonic situation prevailing in the trench bottom provokes the venting, along the fissures on the bottom, of water contained in sediments. Hydrocarbons contained in the sediments are comming out with water and give nutrients for bacteria. Clams, tube warms, sea slugs and shrimps are taking these bacteria as their food and biological communities with exceptionally dense population for the deep sea of more than 3000 meters in depth are formed on the field of accretionary prism and wall of the land side cliff. 3. An intense compressional tectonic field resulted from the subduction is inducing the transition from the subduction of oceanic plate to the collision of a part of the plate to the continental plate.

Jan 1, 1987

By Lawrence M. J

It must be stressed that the following comments are offered only to assist mineral industry professionals in understanding the issues involved in personal liability. The information and views expressed herein are not intended to be a comprehensive guide or definitive statement of the law and they should not be regarded as a substitute for specific advice for individual situations. Readers should consult their own legal and other professional advisers before applying the content of this paper to their own particular circumstances. It is hardly news that work in the mining industry is governed by a complex regulatory and legal system which is constantly changing, but few realise just how directly they can be affected and become personally liable for any breaches. These may result in civil or criminal proceedings and personal assets are at risk. Owners, company directors, managers and now employees are at risk, together with consultants, contractors and suppliers of equipment or consumables, as well as government inspectors. They are liable for their personal decisions to act (or failure to act) in managing operations or carrying out directions, as well as for the actions of others under their control. This paper identifies the areas where such individuals in the open pit mining industry in Australia face the risk of personal liability and measures which can be used to minimise the risk or which can be used to make out a defence to legal action which could arise. There have always been a myriad of Commonwealth, State and Local Government laws and regulations with which to comply, and now international protocols are being used as a basis to impose greater obligations on all people. Once, the `corporate veil' gave some protection to the individual, but today there is negligible protection from the full force of the law. Not only are there various types of law enforcement officers, but public interest groups, shareholders, customers, suppliers, creditors etc may litigate. This paper is not intended to be an exhaustive discussion of the provisions of all the legislation or case law where individuals can be held) personally liable. These areas would include environmental, pollution and heritage law (including Aboriginal sacred sites); occupational health and safety (including workers' compensation) law; trade practices and fair trading law; contract law; corporations law (including the requirements of the Australian Stock Exchange [ASX] and Australian Securities Commission [ASC]); industrial relations law; anti-discrimination and sexual harassment law; taxation (including superannuation trustee) law; and the Common Law. The focus is on the following areas of regulation, which are outside the usual experience of those in the open pit mining industry (the Mining Acts and Regulations are specifically not dealt with here): ò Environment Law; ò Trade Practices Law; ò Occupational Health and Safety Law; and ò Corporations Law.

Jan 1, 1994

By Johnston R. F

The factors which influence the reduction of chromite are investigated with special reference to Coobina chromite. This was compared with a South African chromite ore. The reduction characteristics are outlined and the reduction kinetics studied Temperature has the most significant effect, followed by particle size, silica addition and type of coal.Electron microprobe analysis of the products indicates that iron in the chromite is first reduced at temperatures above 1100°C, followed by chromium at around 1200°C. At temperatures greater than 1200°C metallic iron and chromium are formed simultaneously and subsequently give an iron-chromium-carbon alloy. It was observed that the metallic carbide contains a small amount of silicon. The decomposition of the chromite spinel was observed to pass through the FeO.Cr2O3, MgO.Cr2O3 and MgO.AI2O3 forms before slag formation. It is concluded that Coobina chromite is suitable for the production of ferrochrome if direct prereduction followed by intensive bath smelting is used.

Jan 1, 1994

New Caledonia is a major metallogenic unit of the south-western Pacific Rim. Its mineral production is of world significance and it has an unusually well diversified mining history. New Caledonia's main metallogenetic potential is, however, associated with its unique ophiolitic complex and its important mineral- izations of nickel, chrome, cobalt and iron. Gold has been found in all the four basic tectonic elements of New Caledonia: the Central Massif, the West Coast basalts, the ophiolitic complex and the Caledonian North. Some analogies are attempted. Only the Caledonian North has supported mining operations (213 kg Au). More recently tenuous gold indications have been found within the ophiolitic complex, possibly associated with Oligocene plutonism.

Jan 1, 1987

The Coal Corporation of New Zealand Ltd (CoalCorp) is the largest coal producer in New Zealand, with extensive properties in both the North and South Islands. CoalCorp's North Island operations are kilcmetres to the south of Auckland. opencasts, are located in the catchment wildlife, historical and scenic values. in this catchment is the single most mining operations. centred on Huntly, a town some 80 Five coal mines, four of which are of Lake Waahi, a lake with significant The discharges of mine lodgement water important environmental constraint on Throughout New Zealand the use of water is controlled by a statute called the Water and Soil Conservation Act 1967. All industrial water users are required to hold Water Rights, which are in effect licences to take, use, dam, divert or discharge water. Water Rights are obtained through a legally defined process and any potentially affected party has the per to object to their granting. A special tribunal hears the evidence for and against an application, and issues its decision, which is reviewable in a higher court on Appeal. Rights, if granted, are issued subject to conditions and, in the case of mining discharges, limits would be set on flaw rate, suspended solids concentrations, turbidity, pH and the concentrations of any potential toxicants. This paper presents a case study of an integrated, catchment wide water management plan for Lake Waahi, that was prepared by the author, and others while the author was in the employ of CoalCorp, and its predecessor, State Coal Mines. The author is grateful to CoalCorp for their permission to submit this paper.

Jan 1, 1988

By Van Deventer J S J

The first step in the design of a process to treat a possible economic precious metal deposit should be an examination of the mineralogy of the ore. Using this and other initial tests, the extractive metallurgist can design a process to treat the ore. In the field of precious metal metallurgy, little emphasis is placed on the mineralogical information available to the metallurgist. The information is of far more use to the geologist and the mining engineer. Diagnostic leaching was designed to open up the field of mineralogical analysis to the metallurgist. When a mineralogist looks at the deportment of gold in an ore, he is usually looking for an element which is present in parts per million, so that errors in sampling are multiplied dramatically. Diagnostic leaching offers a cheap, simple, practical alternative. In order to determine with which minerals the desired precious metal is associated, a specific mineral is first eliminated using a selective oxidative leach, and cyanidation is used to extract the precious metal (in this case gold and silver) liberated by the destruction of this mineral. The precious metal extracted can be measured in solution to give a fairly accurate record of the amount of the precious metal associated with that mineral. Furthermore, the residue from this first stage can be subjected to another selective acid leach, and the process repeated. The procedure can be varied to suit the mineralogy of the matrix material. At the end of this diagnostic leach the metallurgist is left with a complete record of the deportment of the precious metal. He can now use this information to design a metallurgical flowsheet to treat the ore. Diagnostic leaching is thus an analytical tool which can be used by the metallurgist not only to examine new ores, but also to look at problems occurring at existing plants. The procedure is not only limited to ores and residues but in fact can deal with any type of intermediary product that occurs on a plant. The information gained from analysing an intermediary product can give a useful indication of how well a unit process is working, eg flotation, roasting, etc.

Jan 1, 1992

By Daziel M, Corke P

Unit cycles in mining have not changed for many years. Productivity increases over the past three decades have mainly been achieved by using larger and heavier machines. This investment in size has probably reached the point of diminishing returns and increased productivity in the future will have to be generated by other means. One way of achieving this is through automation of selected unit operations, eg dragline overburden removal, truck haulage, ground support installation and secondary breakage. Although, in the past few years, there has been significant progress in this direction, we are still a long way away from even partial automation - especially in hard rock mines. This paper addresses the technical obstacles facing mining automation; suggests ways by which these obstacles may be overcome and identifies the role of industry groups and research providers in this process.

Jan 1, 1997

By Hargraves A. J

At 4 MPa gas pres ure and 30°C the sorptive capacity of 10 selected Australian dried coal ranges from 17 to 23 m3/tonne of CH4 and 27 to 36 m3/tonne of CO2. Values for moist coals are about 25 per cent less. At 20°C, sorptive capacities are about 18 per cent greater. No clear relationship between coal rank and sorptive capacity was established.The permeability of coal to gas is dramatically reduced by progressive hydrostatic confinement. No single 'permeability' for a coal can be established because of relative affinities of coals and the gases (Ar, CH4 and CO2) used in experiments. Bedding plane permeability is significantly greater than permeability normal to bedding. Dependent on gas/coal combinations, permeabilities without confinement ranged from 150 to 0.05 millidarcies, and with 8 MPa hydrostatic confinement from 1.0 to 0.001 md. Generally, permeability is increased by reduction in temperature, and reduced by increase in moisture as one changes from Ar through CH4 to CO2. In retrospect, it is preferable to ubject permeability sample to 8 MPa hydrostatic stress only once, because changes occur in the samples and it is difficult to use other gases successively.The initial rate of desorption, DP, does not appear to be a reliable index of proneness to instantaneou outbursts for Australian coals.The methods used for determining quantitative gas-coal properties appear suitable and reliable for testing other coals.

Jan 1, 1985