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Many of the discrepancies that appear when comparing the results of reducing machinery are due to the nature of the materials reduced and the conditions under which they have been treated. It is therefore necessary that manufacturers should employ standard materials in their tests that sufficiently approximate the substances to be ultimately treated if the information is to be of any value to the purchaser. Another advantage to be gained by employing universal standard materials is that by their means one is enabled to compare the relative values of different types of machines. At present much of the data meted out to the public is insufficient to enable them to judge fairly. Of course the best test would be to send some of the stone tor which the machine is required, to be treated by the various crushers in the market that are likely to be suitable for the purpose, but this is not always possible. It would not take long to become accustomed to judge of the value of a machine for a specific purpose if it was guaranteed to work a certain quantity of some standard rock, even if that standard were not identical with the material to be treated.There are many points to be considered before selecting a machine, such as the size of the rough stone it will take, the size to which it will reduce it the proportions of various grades made when crushing to pass through a given mesh the form of the delivered particles the time taken to treat a+ certain quantity the horse-power required to drive the machine, both when loaded and unloaded whether constructed to crush wet or dry the wear and tear of the machine its total weight and weight of the heaviest part the cost of machine what attention it required whether the wearing parts are readily replaced, and several other points common to all machinery. 'When considering these varying quantities, we can tell at a glance certain machines that are suitable for a particular sort of work, and can then compare those belonging to the same class, thus avoiding errors made purposely or through ignotance by persons interested in different machines, who frequently compare machines originally constructed for.

By Dawes S

Efficient roof control in colliery operation is a factor that must be maintained for· the maximum reQovery and economic extraction of the mineral. It must be carefully considered in each of the following stages in the life of a mine.1. The primary development and the first working of the mine.2. The maintenance of access roads, intake and return airways.3. The extraction of pillars.FACTORS IN ROOF CONTROLThe main objects of roof control are: The support of the roof in working places, the relief of roof pressure from the workings during pillar extraction, and in some instances the prevention of subsidence of the surface.The support of the roof during development operations and first working, and the subsequent maintenance of these is influenced by:-1. The depth of the seam below the surface.2. The thickness of the seam.3. The dip of the seam.4. The condition of the roof and floor.5. The method of extraction-mechanical or by hand.6. The method of. working-Iongwall or bord and pillar.7. The availability of material.As a general rule, the pressure exerted by the superincumbent strata may be taken as one pound per square inch for each foot of cover, and the crushing strength of coal as 1,500 to 2,000 lb. per square inch; this, of course, varies, but from these figures it may be assumed that seams below 2,000ft. in depth are liable to crush. If any part of the seam is removed, added weight is thrown onto the remaining coal. It is therefpre essential that for effective working this extra weight must be removed or supported as soon as possible.The outstanding principle in the support of mining excavations is to ensure that the supports are set as soon as possible after the natural support has been removed.Where a system of bord and pillar is applied, the early setting of supports reduces the extent to which the roof bends, thereby reducing the liability to ·tension fractures at the centre of the road.

Jan 1, 1947

Equity finance provides the most suitable and frequently the only access to capital during the exploration and evaluation stages of resource projects when project risk is at its highest. Investors are prepared to provide equity funds in the knowledge that they are compensated for the higher risk they take on with higher potential returns or sufficient upside potential to justify the higher risk. The context of resource projects which determines the role of equity finance has changed considerably. Prior to the resurgence of the gold price and the development of new mining technology many resource projects were selectively mining orebodies by underground methods frequently with limited reserves proved up in advance of mining. The limited proved ore reserves base and the volatility of the gold price all contributed to a higher risk and higher return investment environment in which the use of equity finance was more appropriate and frequently the only option for capital raising. The financial risk of a resources project can be transferred to an underwriter who makes the commitment to distribute the financial risk between a number of investors. There is also the opportunity for financiers to use a mix of equity and debt finance to allow a company to proceed with the development stage where without such a mix the resource project would not proceed. By using a level of equity finance the project becomes robust enough in its ability to service the debt finance facility and the project proceeds with the equity participants receiving a suitable risk reward return. The liquidity from the establishment of a market for the company's securities enhances further capital raising and generally enables the company to satisfy its financial requirements on more favourable terms particularly during bull markets. The role of equity finance in the management of the financial risk during the exploration, evaluation, development and mining stages of resource projects is summarised in Table 1. In more detail the principal roles of equity finance and the ways in which equity finance impact on the risk management of resource projects will be considered in turn.

Jan 1, 1994

By K Dudley, D Readett

The design of entrainment control processes in copper SX plants has been studied by use of models based on achievable plant performance. A number of alternatives have been assessed for their suitability in minimising the transfer of deleterious species from PLS into the electrolyte. The position of the wash (scrub) stage in the circuit, either before or after the loaded organic tank, has been the subject of considerable debate. The modelling shows that at ænormalÆ entrainment levels, the performance of the circuits are very similar. However at high entrainment levels the selection of the wash after the loaded organic storage has significantly lower transfer of contaminants. When considering the inclusion of a loaded organic coalescer the results of the modelling again show that the best circuit has the loaded organic storage/coalescer before the wash stage. The overall control of EW contaminants includes both a wash stage and an EW bleed flow. The total water use for these two flows is shown to go through an absolute minimum. The minimum flow rate is not greatly dependant on the total entrainment from the SX settlers. This can be a useful operating strategy if the quantity of high quality water for make up is limited by the capacity of the water treatment plant (eg RO). However the minimum cost option is to maximise the flow of water to the wash stage and minimise the EW bleed stream. The main driver for this is the cost of the cobalt sulphate contained in the electrolyte. Some results from the latest circuit modifications at the Nifty and Girilambone Copper Projects are presented to confirm the benefits of using both coalescing systems and a wash stage. The EW bleed has been reduced to a level that is less than the loss internally in the SX stage to stage entrainment. There has been an occasional need to add chloride to the EW to maintain sufficient concentration to act as a growth modifier.

Jan 1, 2002

THE object of this note is to set forth some particulars of the effect of light on cinnabar occurring in a deposit of this mineral at Puhipubi, in the North Auckland peninsula of New Zealand. This deposit is contained within a gently-inclined sheet of siliceous sinter forminga hillock called Mount Mitchell, and is particularly notable in that it is an instance of the simultaneous deposition of cinnabar and silica on a large scale. The mercury-bearing material varies in character from semi-porous sinter to dense translucent cbalcedony, of which the former is stained to various shades of pink, the latter to brilliant reds and vermilion. On exposure to daylight-and particularly to sunlight - these colours change to corresponding shades of translucent bluish-grey. As a direct result of this change the Mount Mitchell deposit remained unknown until some ten years ago, for, while prospectors early discovered cinnabar in the adjacent city and in a neighbouring stream bed, none of them recognized this mineral in the bluish chalcedony strewing portions of the surface of the Mount. The writer has carried out a series of experiments designed to indicate the cause and nature of this change, and to form a basis for the elaboration of more delicate experiments which would yield positive information. Circumstances, however, have so far combined to prevent the continuation of the research, and, as there seems little prospect of the writer being able to do more work on the subject, it seems well to publish the data so far obtained. Prior to describing this colour change, the writer would point out the desirability of restricting the meaning of the term cinnabar to the naturally occurring red sulphide of mercury; this would eliminate the ambiguities which arise from its indiscriminate application, in chemical literature, to both natural and artificial sulphides. Further the term cinnabarite having long since fallen into disuse, there appears to be no good reason for retaining the companionterm "metacinnabarite" when reduction to "metacinnabar" would preserve the meaning in a less clumsy word.

Jan 1, 1923

By D Mather

The Resources Boom of the 1960s in Australia provided a strong foundation for AustraliaÆs economic prosperity for the remainder of the twentieth century. In combination with sound economic management, our world-class minerals and energy sector has played a key role in the nationÆs competitiveness, and it has been the major source of our exports since the early 1970s. Even with the emergence since 1990 of major mineral provinces in Latin America and elsewhere, Australia has increased its percentage of world production of several minerals. Between 1990 and 2002, our share of iron ore production rose from 13 per cent to 20 per cent, nickel mine production from eight per cent to 17 per cent, copper mine production from four per cent to seven per cent and zinc mine production from 13 per cent to 17 per cent. Whether this situation will continue during the coming decades motivates the discussion of this reflective paper. The approach is to consider fundamental supply-side and demand-side issues in arriving at a view about the state of the world, the world minerals sector and the Australian resources sector in the coming decades. The argument draws from the experiences of other mature mineral producing countries such as Canada and the United States. In such nations, efficient producers have often sustained competitiveness for extended periods, despite falling grades and other challenging operating conditions. Yet several forces are changing the economic geography of the minerals industry in significant ways. These include the re-emergence of major global mining corporations, the revision of mineral policy in over 100 nations since 1985, the mobility of technology and more efficient transport both for mineral productions and mining professionals. Given these trends the paper argues that the Australian mining industry must continue to change and evolve significantly in the foreseeable future. Its leaders will need to be even more internationally focused if it is to maintain its strong competitive position.

Jan 1, 2006

By D A. Williams

The conventional method of transporting mine tailings from a process plant to a tailings storage facility (TSF) is in the form of a low to medium density1 slurry, which can be pumped using centrifugal pumps. Over the past several decades, therefore, mine operators have generally adopted this default approach. There are, however, some convincing arguments why consideration should be given to thickening the tailings slurry to a higher density paste consistency. In particular, the minimisation of environmental impacts, the reduction in water consumption and the cost savings relating to TSF closure make paste an attractive option for the life of mine tailings disposal. There are several environmental impacts that are associated with a conventional slurry TSF, such as land sterilisation, aesthetics, dust, seepage and acid mine drainage. Some of these impacts, such as dusting, may be difficult to mitigate while the TSF is in operation. Others can be influenced by adjustments made to the tailings slurry density at the plant. Unplanned fluctuations in slurry density and/or viscosity can have a significant influence on TSF performance and can exacerbate the environmental impacts relating to the facility. Relatively minor changes in the solids content of the slurry can affect tailings beaching behaviour, degree of segregation, position of the phreatic surface, amount of freeboard, consolidation behaviour, placed (settled) density (and hence TSF capacity) and in situ strength of the tailings. Paste is a non segregating slurry and many of these effects can be minimised at the TSF when the tailings slurry is thickened to a paste. These improvements are manifested by reduced seepage, flexibility in selecting an appropriate final landform, ability to rehabilitate progressively and reductions in plant water usage. It is possible to minimise environmental impacts of a TSF through the use of tailings paste. Ideally the paste production plant should be part of the initial design of the process plant. However, significant benefits can be gained by adding a paste production plant at some time later in the operational life of the mine to reduce environmental impacts and facilitate an environmentally acceptable TSF closure.

Jan 1, 2002

It is a commonplace of our industry that prices of most minerals have been historically weak during the 1980s. The International Monetary Fund's index of prices of metals fell 25 per cent between 1980 and 1982, rose slightly in 1983, and has since fallen further. In December last year it was 37 per cent below its 1980 average. The few temporary exceptions to the mineral industry's malaise highlight the excess capacity, which largely explains the weakness of prices. The industry has painfully come to recognise that more satisfactory prices will not be restored until supply capability and demand move back into better balance. Mine capacity was installed in the expectation of much faster growth of demand than has occurred. For a variety of reasons mine and plant closures have been insufficient to restore equilibrium to the market-place. The industry may, therefore, have to resign itself to continued weak prices for some years more, at least by the yardstick of the 1970s. Growth rates of demand have slackened off in line with economic activity, and in response to continuing substitution and technological improvements. To the extent that the recent weakness of oil prices stimulates the industrial countries' activity, demand for non-fuel minerals may grow faster than most forecasters now predict. It is, however, much too early to say how long the weaker oil prices will persist, and even more difficult to estimate their probable effects. In typical post-war business cycles the usual response to recession was to batten down the hatches, and ride out the storm. Sooner or later, and probably sooner, demand resumed its previous trend path, and prices recovered. The market, in effect, bailed mines out of trouble; the more efficient could make attractive pre-tax profits whilst even the poor to mediocre could earn a satisfactory living. Prices rose at least as fast as general inflation, and in the early 1970s much faster. In retrospect those price rises of the early 1970s were historically abnormal but they did not appear so in the prevailing inflationary climate of the time. When the market failed in the early 1980s many of the hardest hit companies looked for scapegoats.

Jan 1, 1986

Over the past 18 months the De Beers Consolidated Mines Ltd operations have made a concerted effort to move away from using the traditional shock tube initiating systems. These systems are being systematically replaced by the use of electronic delay detonators (EDD). Various trials were conducted in both host rock and kimberlite rock masses to improve tunnel advance as well as to optimise delay timing during trough openings (Ngoma et al, 1999; Mohle, 1999; Baltus, 2000). The high cost of EDDÆs, when compared with traditional initiation systems, led to a number of detailed studies being conducted on the mines where EDDÆs were being used. These studies aimed to quantify the additional benefits when blasting with electronic detonators. The studies showed that the change was justified on the basis of increased quality control and reliability gained through the use of EDDÆs. However, these benefits attract other related benefits, like fragmentation control, and backbreak reductions. When compared to the shock tube initiating systems the increased development face advance and the reduction of oversize during production blasting using EDDs, compared favourably to the less costly systems. As blasting engineers gained experience and confidence in the use of the system bigger blasts were initiated in mass under-cut blasts and slot raise development, by using multiple hole firing and second delay periods between holes. In the open pit and sublevel open stope mining methods the control of the fragmentation distribution and the effect of the mass of explosive detonated during a blast is detrimental to the loading and hauling production rates and the stability of the rock mass behind the blast. With a stable rock mass the bench cutting can be executed to establish steeper overall slope angles leading to large cost savings due to a reduction in waste stripping. It is the purpose of this paper to indicate through quantification that the use of the EDDs as an initiating system improves all-round blasting performances and assists in meeting customer requirements. The customer being the ore treatment plant.

Jan 1, 2001

By J Centofanti, D Conti, R Riske, C Morley, A Cook

Why is it so difficult? Why are there differences throughout the resources industry in how reconciliation factors are reported and calculated? Why is there no standard formula to use? These are common questions asked when mining companies try to compare reconciliation results across operations or attempt to undertake internal or corporate governance reporting processes. For many mining companies the calculation of reconciliation factors is often a very time and resource intensive part of mandatory reconciliation reporting. Some major mining companies, that move millions of tonnes of material per annum, dedicate full time resources to the calculation of reconciliation factors. The willingness of these companies to set aside resources demonstrates the value that operations place on good reconciliation reporting. Reconciliation is about measuring the variance between two like measures at different points along the mining sequence. It can be undertaken between predictive models, forecast plans and actual measured performance. Calculations are used to derive a variance between two sections within the mining sequence, with the result being commonly known in the resources industry as a æfactorÆ. Mining companies use the calculation of reconciliation factors as key performance indices (KPIs) to provide a æhealth checkÆ of their operation, with variances often pointing to issues either with the accuracy of the original estimate or the quality of the measurement being used in the comparison. There are many reconciliation factors that can be calculated and reported. This paper will set out, clarify and provide a recommended standard means of calculating each specific factor that, where adopted by a company, will ensure compliance with the international reporting codes, such as JORC. Using case studies from Rio Tinto Group (Rio Tinto) and BHP Billiton Mitsubishi Alliance (æBMAÆ), and the authors experience across a wide range of mine sites, the outline of a generic solution for tracking a parcel of material from the pit through to the port along with appropriate reconciliation factors is provided. The intention of proposing standardised reconciliation factor terminology and methodology is to provide the foundations of a system to enable communication and comparison across different commodities, companies and mines sites.

Jan 1, 2009

Three transient phenomena have been observed and experienced in the operation of large solvent extraction mixer-settlers. These relate to the ability of the settler to discharge streams with low entrainments arising from different phase separation æproblemsÆ. The operation of large-scale laboratory and commercial solvent extraction settlers has been shown by a number of workers to be a dynamic process, especially at the feed end. Circulating flow patterns are common in all three organic, aqueous and emulsion phases. The circulating patterns in deep dispersion bands in long settlers are believed to form roll fronts that can travel down the settler length within the bounds of the dispersion band. Various physical models are proposed to illustrate the formation and movement of roll fronts within the dispersion band. Another transient phenomenon has been observed in commercial settlers operating without any dispersion band. Entrainment of the continuous phase in the advancing dispersed phase is at high and erratic levels. This supports the conventional separation model, which recommends the presence of a significant depth of dispersion band to æfilterÆ the secondary haze from the bulk separated phases. The third transient is the position and shape of the dispersion band within the settler. Large commercial settlers have been shown to exhibit high variability in both these aspects of the dispersion band. The elimination of all three transient phenomena in commercial settlers has been shown to be effective with an in-settler media of coarse size and moderate specific surface area. The effect of the media is two-fold: it dissipates both the circulating flows and the forward velocity of any roll fronts, and creates a stable deep dispersion band at the feed end that serves to trap secondary haze from the primary coalescence process. It is effective in treating both types of transients involving non-existent or excessive dispersion band depths. The media serves to enhance coalescence by providing a static surface of intermediate surface tension on which droplets can collapse. The random nature of the media also provides multiple stream splitting and re-combination, that presents further drop to drop and drop to media impingement, which in turn promotes coalescence.

Jan 1, 2000

By Cerutty L

To those who have been engaged in the construction of mining and metallurgical plants during the war and post-war periods, it is quite unnecessary to point out the large increases and violent fluctuations in prices of basic commodities and the steady and persistent rise in labour costs. It may, however, be of interest to present these facts in graphic form, and survey the relative heights of the various maxima and the lead and lag of individual waves. Since Descartes demonstrated for us moderns the analogy between geometric form and algebraic statements, the two-dimensional graph has found widespread application. Mathematicians have developed for our information, if not for our confusion, the triangular diagram and the solid three-dimensional figures, which have proved so useful, at least in the hands of the metallurgists at Port Pirie. The model (Plate 1.) which is exhibited here does not pretend however, to indicate the connection between any three inter-related variables, and it is not proposed to burden members with any abstruse mathematical expression for the irregular surface of the blocks. While time is an ordinate common to all sections of the model, each illustrates separately the variation in cost of some particular quantity between the years 1914 and 1922. It is an easy matter to record such individual variations, but it would be an impossible task to state any equation describing accurately the dependence ot the prices, say, of hardwood or of galvanized iron upon that of labour at any particular point of time. The cost of living curve, which has attained such prominence, if not notoriety, in the last few years, is the result of an attempt to show the mass-effect of the components. It is the difficulty found in "assigning the correct weight to the separate items which makes the aggregate curve somewhat misleading at times.Turning to the model, it will be noticed that each section consists of half a dozen pegs.. The first in each row,that coloured red, represents the cost of some particular quantity, such as bricks, timber or coal, at Broken Hill in 1914. The next peg, that coloured blue, represents proportionately prices for that quantity in Hobart during...

Jan 1, 1922

By M Noy, P Hawkes

Improvements in the drill and blast process can impact on loader performance in a number of ways. The main effects being improved loading cycle times, less non-productive cycles such as oversize removal, clean-up and face raking and better bucket fill factors. The impact of improved loading cycle times on the overall cost and productivity of the load and haul cycle is very much dependent on the loader truck match and the management of the haul fleet. Previous work has shown that a 20 per cent improvement in dig cycle times may only lead to three per cent or less improvement in the overall productivity of the load and haul process. However, improving the mass loaded per pass by five per cent will lead to a five per cent improvement in productivity for any given haul fleet situation, assuming sufficient truck capacity. Work by Orica Explosives at Lab ChrysotileÆs Thetford Mine, Quebec, Canada showed a relationship between muckpile fragmentation and truck payload. With this in mind, work was carried out to determine the effect differing muckpile fragmentation distributions can have on excavator bucket fill factors. This work was performed in the laboratory to a 1:100 scale. Nine different distributions were used. These were characterised by the Rosin Rammler parameters, xc the characteristic size, and n, the uniformity index. The values of xc and n used were modelled on those previously measured at a Sydney quarry. For the range of distributions measured, it was found that the fill factors were lowest at a low characteristic size and a high uniformity index and highest at a high characteristic size and a low uniformity index. In other words the best fill factors were achieved with a more dispersed muckpile distribution with a larger characteristic size. The difference in fill factors was 16 per cent indicating that controlling the drill and blast process to produce a specific muckpile distribution can have a significant impact on the overall cost-efficiency and productivity of the load and haul process. Field measurement by Orica Explosives at a quarry in Canada supports this conclusion showing improvements of up to seven per cent in average bucket load by either increasing the characteristic size or decreasing the uniformity index of the muckpile.

Jan 1, 1999

Risk Management has been applied relatively slowly in the mining industry. Except for the risk concept application in financial considerations, the application of Risk Management in safety management has been far from satisfactory. When applied it was treated in a global occupational safety and health sense. Regardless of how much the mining industry has progressed over the years it is still, in many respects, `state-of-the-art' business. The safety aspects of mining are well known and yet little understood by the public. Regardless of what has been achieved so far and how much effort has been put into it, mining is regarded as an unsafe and somehow rude business. Safety records of the mining industry vary from State-to-State. Latest mining related disasters in PNG and Queensland and some other fatal accidents support this public perception. They purport a need for change in managing safety in the mining industry. The latest mining fatalities have raised the issue: What must be done to improve safety standards? Duty of care, risk management and system engineering concepts can provide some answers. Risk Management principles which have been advocated for some time provide many answers and explanations and can make safety management more constructive and workable. What has been missing so far is that this concept has neither been applied nor has been modified for its practical application and purpose on a larger scale. A risk management approach to the management of safety and health in the mining industry is addressed, herein. This approach does not attempt to provide the solution. It does, however, provide a basic understanding of what Risk and Risk Management are all about. Rational management of risk is addressed in the life cycle and system contexts. A system of continuous improvement is applied. There is always a chain of events, outcome, exposure, consequence(s), and consequence(s) value(s). It means that development of an event takes place in time and space. Dynamic circumstances have been created in or within the system. It is a decision-making process designed to provide a methodology which is directed not toward a mathematical model but toward easy use and application in dynamic working environment, by decision-makers who can be anybody from either a risk taker or a risk creator. The emphasis is placed not only on arriving at the best practical, possible and fair decision but also on structured and systematic acquisition of knowledge about the system, its hazards and associated risks, hence increasing the decision maker's ability to manage the decision-making process related to the management of risk.

Jan 1, 1995

The quality of the external water source for a mineral processing plant may influence the extent to which the environmentally desirable practice of recycling of water from plant products is possible. This is particularly likely for froth flotation plants where the chemical quality of the water may affect the plantÆs performance. The quality of the external water source or the recycled water can be improved by a water treatment step, and in turn the extent of recycling which can be tolerated is able to be influenced. The quality of the external water can range from very high quality, soft water derived from melting snow, to poor quality, hard water (high levels of dissolved calcium and magnesium) from underground aquifers, and to even lower quality sea water (very high levels of dissolved species including sodium chloride). It can be noted that some underground water is more saline than ocean water as well as containing high levels of dissolved calcium and magnesium. Occasionally, a different source of water is utilised in the wet and the dry seasons. Increasingly, sewage water from cities is becoming a potential external water source with sustainability implications. If the initial quality of the external water is high, the scope for recycling of water from all the products is maximised. Such reuse or recycling of water from the products allows chemical species from oxidation of the ore and from other inputs to the process such as reagents to increase in concentration in the water returned to the plant. Such accumulation of species can have negative effects on the performance of a process such as froth flotation but instances of positive effects exist. Some reagents which are used in flotation plants such as lime or sodium carbonate also happen to be commonly used for independent water treatment plants. Hence, the flotation process may inadvertently provide some aspects of water processing. Where the quality of the water in the feed to a mineral processing plant (external water plus recycled water) is not an issue, more powerful solid-liquid separation processes can be considered to maximise the removal of water from the products and its reuse. Such processes may also have complementary benefits in a sustainable mineral industry by, for example, producing a tailing stream with a higher per cent solid value which is more suitable for safe storage on the surface or underground. This paper documents findings on the effect of water quality on the flotation process. It also considers current directions of change in the need for increased removal of water from plant products. It then considers the implications of these trends for maximisation of water recycling by such operations.

Jan 1, 2003

This is the seventh major symposium organised by Illawarra Branch over the past five years and the fifth dealing with various aspects of coal. It is clear that all of you here need no convincing that black is beautiful! This symposium is on a broader canvas, covering the overall field of occurrence, preparation and utilization of black coal throughout Australia. It is thus the most comprehensive treatment of the subject by the Institute since the symposium organized in 1950 by the Sydney Branch with the co-operation of the then newly formed branches in Newcastle, Illawarra, Central Western N.S.W. and Southern Queensland, all of which shared coal as a major interest. The 1950 symposium was adopted as a volume in the series of seven published by the Fifth Empire Mining and Metallurgical Congress in 1953. This historical reminiscence brings to our minds the circumstances in which these new Institute branches were formed. This happened in the year of the presidency of the late Frank Hockey, and at the time the Australian black coal industry was in many ways at a very low ebb. It was the time of extreme shortage of coal following World War II, and the industry was beset by industrial unrest on such a scale that daily bulletins were posted listing the number of idle pits, of idle miners and of tons of lost production. There could not, of course, be any thought of export marketing. Some of the more picturesque bulletins recorded the number of pits at which the ceremonial emptying of billies took place, and the number of pits at which the aroma of the horses' breath was insupportable. At an Institute conference at the time it is on record that the late lamented Austin Edwards, that tireless mineral researcher, author and editor, in his gentle way chided the personnel of the industry and the members of the Institute for having allowed a situation to develop in which a whole generation of Australian children could grow up without ever having seen coal or knowing what it was. It is sad that most children and most Australians have still never seen coal, and think of it as something dirty and uninteresting. The desperate situation of the black coal industry inspired moves by people in industry and in governments, whose plans and efforts have been recorded elsewhere, to modernize coal mining methods, to introduce coal preparation, and generally to restore the mines and the mining communities and to re-cast the steel industry and electricity generation. Amelioration of the traditionally troubled industrial relations was an integral part of this overall programme, and whilst one would wish this aspect had progressed further the situation has, in fact, improved immensely. New investment in exploration, mining, preparation, transport and utilization both by the existing coal mining groups and by new entrants, Australian and overseas, have played a large part in bringing about the transformation of the industry to such a point that Australian needs are being fully met and a large export market is being supplied - a situation that few would have dared to hope for in those dark post-war days. Forecasts of exports from New South Wales and Queensland show coal becoming a dominant foreign exchange earner for an indefinite term. Old King Cole may have vanished from our children's nursery rhymes but King Coal is here to stay, providingthat costs in the industry can be kept within competitive limits. It is all too easy for an industry to price itself out of the export market by inflation, by increased costs for a variety of reasons, and through currency readjustments. A second proviso is that we must continue to encourage a balanced attitude to environmental matters.

Jan 1, 1975

By C Sennersten, A Hellicar, C Lindley

Traditional methods of resource modelling and mine planning rely upon geostatistical methods applied to exploration drill core data to derive a three dimensional model of the distribution of metal grades, quantised into rectangular prisms or blocks. The resulting block model is a primary input into short, medium and long term mine planning. However, block attributes are averaged or interpolated over a complete block, meaning that information at smaller scales is lost to the mine planning process. Grade engineering for new mining methods, such as the development of more accurately controlled blast designs, continuous miners for hard rock and sensors for rock properties that can be distributed along the operations process and value chain, allows excavation to be much more selective than traditional blasting, and provides data for driving earlier separation of waste from ore. This selectivity can be optimised if the resolution of resource models can match or exceed the spatial resolution of selective mining technologies. Opportunities for selective mining increase as a deposit becomes more heterogeneous. This leads to an interest in methods for estimating the distribution and characteristics of mineral heterogeneity within the ore-body. The objective of this work is to present some definitions of mineral heterogeneity, and to explore how heterogeneity as defined can be measured and inferred within ore-bodies.CITATION: Hellicar, A, Sennersten, C, Lindley, C and Evans, B, 2018. Heterogeneity assessment for grade engineering in complex ore bodies, in Proceedings Complex Orebodies Conference 2018, pp 11–13 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By G R. Hancock

A common and cost-effective method for post-mining landscapes is to construct linear hillslopes with a break in the hillslope at appropriate distances to reduce hillslope length and resultant erosion risk (Figure 1). The break in slope occurs at a point that has been found by local experience to be appropriate for the materials and climate. Further enhancement of the linear hillslope may be assisted by surface treatment such as ripping (Saynor, Lowry and Boyden, 2019) (Figure 1). Firstly, ripping introduces surface roughness which breaks up flow paths reducing flow velocity thereby reducing erosion potential. The depression produced by the ripping acts as a trap which captures water, sediment and organic matter

Aug 2, 2023

By M J. Cole, J Zhou, D J. Borrow, S M. Iveson, K P. Galvin, J L. Sutherland

New technologies can easily take around ten years to commercialise. Strong research support is needed in parallel with the process of innovation and commercialisation, in building a deeper understanding of the underpinning physicochemical and hydrodynamic forces that deliver the separations, in achieving improvements, in the deployment of a new technology, and in expanding the innovation platform to create new IP. External investment beyond the research, derived from the genuine value proposition of transformational change, funds the pathway for traversing the so-called Valley of Death.

Aug 24, 2022

By C J. McKenzie, D F. S Natusch

The lignite deposits of Southland and Central Otago are a potentially significant energy resource for New Zealand. Current estimates put the technically mineable lignite reserves at 5.3 billion tonnes, which is more than ten times the energy content of the Maui gas field. Thus, the strategic importance of the lignite as a basis for maintaining current levels of self-sufficiency in transport fuels, or as a possible feedstock for electricity generation, deserves full investigation. The full extent of the lignite deposits was only recently established as the result of a scout drilling programme undertaken between 1976 and 1979 by the Mines Division of the Ministry of Energy, and from companion studies conducted by the New Zealand Geological Survey. These discoveries of large quantities of lignite coupled, at the time, with rising oil prices, raised the prospect of their development for production of transport fuels.

Jan 1, 1983