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By D Landriault, G W. Wilson, L Langetine and

Engineered soil covers are used for final closure options for both waste rock and tailings disposal facilities. Currently, cover construction requires excavation of appropriate cover material from a nearby site. If no suitable materials are available, the mine operation may have to ship appropriate materials long distances to the site before the construction of the cover can even begin. This has led to the proposal to engineer cover materials using existing waste materials from the mining operation. The paper presented here describes the results of a laboratory scale testing program to evaluate the potential for blending waste rock, smelter slag and tailings for the creation of a suitable cover material at a site in Canada. Tailings from the local mill, waste rock and slag were collected in the field and blended to create a material with an air entry value similar to the tailings and with physical strength similar to the waste rock. Testing indicated this mixed material could be blended at a consistency of a paste and was suitable for pumping. It can also be compacted to a high-density material. The preliminary results show that it may be possible to blend waste rock, slag and tailings into a material that can be utilised in the construction of a water retaining cover.

Jan 1, 2003

During the course of an investigation into the fundamental chemistry of the cyanide process, it became evident that the usual method of determining protective alkalinity was not completely satisfactory. T.he routine method for the determination of protective alkali by first removing free cyanide by the addition of silver nitrate, followed by titration of alkali with dilute acid using. phenolphthalein as indicator, can be shown to give correct results only when the alkali is a strong base. For other sUbstances, the alkali so determined is not the protective alkali. In view of the complications associated with the presence of zinc in cyanide solutions the discussion will be restricted in the first place to solutions free from zinc. Until the chemistry of simple cyanide solutions is placed on a quantitative basis it will be difficult to elucidate the behaviour of complex mill solutions.By the use of physico-chemical theory, it is possible to treat certain aspects of 'the chemistry of cyanide solutions in a manner which not only illustrates the important variables involved, but which also shows the need for care in interpretIng results obtained by conventional methods.In the following, comparatively simple systems are discussed; the principles established should be of use in interpreting the behaviour of more complex solutions. The methods described are not intended for routine work, but may be regarded as supplementary to the usual analysis carried out for the control of plant solutions, or as alternatives to be used when the latter do not appear to be satisfactory.

Jan 1, 1948

By Boyle L. A

A positive displacement pump is being dev eloped for pipeline transportation of coking coal to a -50 mm export specification, at a con- centration and velocity which will allow trans- portation in the plug flow region, minimising degradation of the particle structure, and pipe= line friction losses which will be lower than with turbulent or laminar flow. Pump operation is by hydraulic powered free pistons in a rota- ting cylinder block, with cylinders overlapped by stationary inlet and discharge ports in a water lubricated and sealed rotary valve. Before this development coking coal was not considered suitable for transportation in slurry form, for the valves in the double act- ing duplex piston pumps used for slurry pipe- lines, cannot be divorced from the slurry and require that the solid material must be reduced to a fines'consistency before introduction into the pump suction. The hydraulic transportation of 10 million tonnes of -50 mm coking coal, 50 km from the Bargo area west of the escarpment to an offshore shiploader at Port Kembla is feasible. Study shows that economic factors alone would dictate that the development of a pumping system for long distance transportation of coking coal is necessary. The greatest impact from the slurry transportation of coking coal would be the

Jan 1, 1976

By Somerville M, Muray A, Bocking M

Australia has an extremely large total hot dry rock (HDR) resource above a depth of 5 km, equivalent to 7500 times its present annual energy consumption, of which 80 per cent underlies the Great Artesian Basin. The resources most likely to be exploited first are those residing in homogeneous granitic bodies beneath sedimentary basins containing insulating rocks such as shales and coal measures. In the Sydney Basin south of Muswellbrook, an area of high geothermal gradient corresponds to a gravity low thought to be a buried granite body at a temperature of possibly 250¦C. This locality is suspected to have the ideal geological characteristics for Australia's first hot rock test facility. Australia's high HDR potential is possibly unique in the world, in that the potential sites satisfy four independent, geological conditions, each considered as favourable for the creation of a resource, and for the ease of extracting that resource. They are: ò Higher crustal heat generating capacity than that of normal continental crust. ò Much of the Australian continent is covered by sedimentary basins which contain a high proportion of shales and coal measures that have low thermal conductivities, thus providing an insulating blanket for the heat being generated beneath. ò The sedimentary basins are in many places underlain by large untectonised granitic bodies that are not only a major contributor to heat generation, but also ideally suited to the establishment of HDR reservoirs. ò The crustal shortening stress field that is found in the majority of the Australian continental crust results in a vertical minimum principal stress orientation which should result in the development of favourably oriented horizontal stimulation cells necessary for maximising an HDR resource.

Jan 1, 1995

A simple method of designing effective fill drainage systems for slurry backfill is presented. By using the proposed method, it is easy to calculate and predict the expected fill drainage rates or to provide additional drainage systems to accelerate the fill drainage. The fundamentals of hydraulic fill and an efficient method to determine its permeability is also explained. The safety in hydraulic filling and bulkhead stability depends totally on achieving effective drainage regime for the fill. This paper provides the basis for creating such efficient drainage regimes. The recent fatal fill bulkhead failures in Australia were the result of poor drainage from the respective fill masses, and therefore it is more important to provide suitable drainage arrangements to continue using hydraulic fill to the benefit of the mining industry. At present there is no procedure available to mine operators to estimate the expected bulkhead pressures to design a satisfactory bulkhead. Some mines are constructing bulkheads after their initial investigations carried out years ago. Other mines have simply borrowed the ideas from the pioneer mines and using in their areas. It is high time that we develop a rational approach to estimate the expected bulkhead pressures for the design of bulkheads. We need a simple model that could be understood and used by the mine operators on a day-to-day basis. This paper also presents a model to predict the bulkhead pressures for designing safe bulkheads.

Jan 1, 2002

By Conway KM

The traditional role of Australian Consultants in project development has been until recently restricted to the provision of discrete packages for survey and engineering services during the feasibility, design and construction phases of a project. Management of such projects was the province of the owner/developer or his agent. However, Australian Consultants are now being con- sidered for an expanded role on resources Projects.

Jan 1, 1983

This paper summarises the performance of the gold exploration industry in the Western World since 1970, with particular emphasis on the period 1985 - 2003. It identifies the number and size of major (ie >1 million ounce) primary gold discoveries made over this period by location and type of company. Estimates are also made of the likely contribution from smaller discoveries down to 0.1 million ounces. It also assesses the overall trend in the percentage of grassroot discoveries that are converted into mines, and the time taken to get them into production. By comparing the discovery data against total exploration expenditures it is possible to determine the average unit cost of finding a major gold deposit. It is significant to note that the average unit cost per discovery and per ounce of resource has tripled over the last 30 years. An attempt is made to determine the overall economic value generated by the industry. This is based on a detailed analysis of the rates of return and the Net Present Values (NPVs) of 109 major gold projects. After including an adjustment for discoveries not modelled, the NPVs are compared against the total amount of money spent on exploration to determine the value-to-cost ratio for the industry. Based on historical spot gold prices and tax rules, it is found that the return on investment for gold exploration in the Western World over the period 1985 - 2003 was around five per cent real after-tax. The returns achieved in the US and Australia was significantly higher than that for Canada. The returns also appear to have declined in recent years. With regard to the relative performance of junior versus major companies, the paper estimates that the junior sector accounted for 30 - 40 per cent of the total exploration expenditure, and were was associated with 34 per cent of the total number of major deposits, 27 per cent of the contained ounces and 25 per cent of the economic value found.

Jan 1, 2004

Agitation leaching data has generally not been analysed to extract the maximum amount of information that is available. Analysis of heap leaching systems has been developing over the last five years to include the underlying rate determining process. This has been found to be diffusion control for all copper leaching; irrespective of whether they are oxide or sulfide minerals. Extension of the diffusion model has enabled better scale-up protocols to be developed. Acid consumption in copper heap leaching operations has been found to be a first-order chemical controlled system. The analysis of the data is relatively straightforward. However the interpretation and scale-up is not as direct as for agitation leaching. The differences in the residence time distributions (RTDs) are required to properly account for the scale-up between test columns and field. The leaching of oxide copper in agitated systems has also been found to be diffusion controlled. However, there are significant differences in the control mechanisms. Initially the leaching control is the supply of acid to the mineral surface. This is limited by the diffusion through the surface boundary layer and is thus subject to the level of agitation. Higher agitation provides thinner boundary layers and faster diffusion rates. Similarly, higher grade material creates a thicker concentration boundary layer and relatively slower leaching. Acid consumption in agitated leach systems is also a first-order system. However, the interpretation of the RTD is easier from batch testing to continuous multiple CSTR series plant operations. Altering the method of acid delivery can significantly reduce acid consumption rates. Predilution of the acid minimises the local acid concentration near the addition point and can reduce the consumption by up to 50 per cent. Modelling of the combined leach rate(s) and acid consumption rates in agitated systems allows comparison of various leaching strategies and selection of the most appropriate. Similarly, the model allows the identification of economic limits to leach recovery; where the cost of acid consumption is greater than the value of the copper recovered. From this analysis selection of residence times for agitation leaching can be determined. The modelling tools are useful in identifying optimum conditions for the leaching process.

Jan 1, 2005

By Corbett GJ

Epithermal gold-silver deposits occur in young volcanic terrains where post-mineral cover commonly impedes the search for mineralisation. At the Togi Project in Honshu, Japan, a complex mineralised system is largely covered by post mineral volcaniclastics. A combination of high resolution electrical resistivity surveying and detailed airphoto interpretation has, with close geological control, enabled synthesis of structural and alteration characteristics of the Togi geothermal system, in turn permitting ranking of the prospects for drill testing.

Jan 1, 1990

By I D. Hair

A numerical groundwater model was used to predict the nature of interactions between heavy mineral sands mining operations and the groundwater regime at North Stradbroke Island, Southeast Queensland. North Stradbroke Island is formed mainly of massive vegetated Cainozoic aged dune sands. Since the 1950s, a number of operations have mined rutile, zircon and ilmenite on North Stradbroke Island. In such mining operations, a dredge and an associated processing plant are floated in a pond either above or below the prime groundwater table The numerical model was based on the North Stradbroke Island Groundwater Management Model, developed in 2001 by the Department of Natural Resources and Mines (NR&M). This model was constructed using the modular, cell-centred, finite-difference groundwater flow model, MODFLOW, developed by the United States Geological Survey (USGS). The NR&M model was refined to improve model resolution and detail for simulating dredge mine paths. Of particular interest were: water table fluctuations induced by mining for the identification of slope stability risk; the optimisation of sand spear arrays supplying mine make-up water requirements; inflow and outflow rates to the dredge pond for overall mine water balance; and interactions with Eighteen Mile Swamp and water supply bores controlled by the Redland Shire Council (RSC). Depending on the water level in the dredge pond compared with the surrounding groundwater table, water either flows out of the dredge pond into the groundwater regime or from the groundwater system into the dredge pond. The MODFLOW river package (RIV) was utilised for the modelling study. Dredge pond movement was simulated using specialised software developed by Watermark Numerical Computing (WNC) to interpolate pond positions and map the dredge path to the model grid both spatially and temporally. As tailings placement affects the groundwater system through increased recharge, the MODFLOW recharge package (RCH) was utilised to simulate different recharge efficiencies. Long-term model predictions were made for the period from July 2002 to May 2021. Results of the modelling showed that exchanges of flow between mining operations and the groundwater regime could be effectively managed. The study provided valuable information which was used to develop an appropriate mine water management plan.

Jan 1, 2003

The society in which we live is one of change, and we professionals are part of that society. The importance of this simple and obvious statement is often overlooked. My Presidential Address examines the question: can professionalism survive in our changing society?There is ample evidence to show that our society is changing, and that the rate of change is exponential. This rapid and accelerating rate of change is what Alvin Tomer refers to as "future shock". Rapid change means that we do not have time to become accustomed to what is happening around us and to feel comfortable with it; the greater the rate of change the greater the discomfort. The effect that this has on people is varied; the change may be either expected or totally unexpected.The rate and extent of change in society is not the same for all countries nor for all industries or occupations. Change is more rapid in Japan, Korea or Taiwan, than in Australia. It is more rapid in our cities than in the bush, more rapid for professional businessmen than for farmers. In our minerals and petroleum industries, we are still adjusting to the great changes that have taken place over the last fifteen years. In the past, products from our industries were sold on a free and open market. Today, mineral development and production in most undeveloped countries and some developed countries is manipulated for political, social and economic reasons. Changes of this nature have had a devastating effect on the operations of established mineral producers in the democracies.Because of the accelerating nature of change, we must recognise that the past is not a reliable guide to the future.Although extrapolation of the past into the future is a basic ingredient of commercial survival, extrapolation is less and less reliable.I borrow from others in quoting the Irish proverb: "The future is not what it was".The future is where our business lies and most of us at this Conference must endeavour to understand it and adjust to it. I believe in the old adage that:You can't know where you're going if you don't know where you've been and where you are at.There are a number of major factors which have created change within our social, economic, and industrial environment in recent years.

Jan 1, 1985

Since the 1970s we have seen a marked corporate response in terms of the environment. In part this has come from regulation but it has largely come from stakeholders and the community. We now see a similar trend towards sustainability. The Brundtland (1987) definition of sustainable development provides a direction for advocates: the advance of human prosperity in a way that does not compromise the potential prosperity and quality of life for future generations. In my view its three essential components are: economic, environmental and community. The Global Mining Initiative and the contributions to the Rio World Summit and the Johannesburg World Summit on Sustainable Development indicate that sustainability is being taken very seriously by the mining industry. But does the minerals industry really embrace sustainability as they claim? There is a view that in reality sustainability is a non-event and that the triple-bottom line approach is only a convenient catch-cry for companies who are actually focussed very strongly on the economics part of the equation. Chemical engineers are showing a strong trend to more sustainable practices and the chemical industry has shown real commitment to research into developing sustainable processing systems. This requires a framework for thinking and design and the chemical industry is demonstrating true innovation as it moves towards æno wasteÆ technologies. Whilst there are limits to the rates of change that can occur the minerals industry should also be moving in a much more determined manner towards the notion of processing of products designed for whole-of-life cycle û with minimum/no waste. But is the minerals industry just paying lip service to the importance of research to sustainability?Several common themes influence the science and innovation agenda in Australia, which will affect the development and adoption of innovations by AustraliaÆs minerals sector. First is the well-proven link between peer-reviewed scientific excellence and commercial application. Second is the rise of multi-disciplinary Mode 2 research, which has developed in response to the complexity of problems faced by contemporary researchers, which are best analysed by combining expertise from two or more disciplines. Successful innovation outcomes, in any field, including minerals processing, is promoted by Mode 2 research which benefits from greater levels of networking and collaboration. Kofi Annan in his Message to the World Social Forum puts it very succinctly æThe way forward lies in finding constructive solutions togetherÆ.

Jan 1, 2004

By Walker V

The 'MAGNADET' to provide a safe enhanced protection extraneous currents, electricity and radiodetonator was designed electric detonator with against the effects of current leakage, static frequency energy.It has found a particular niche in shaft sinking operations and Mount Isa Mines initiated trials of the system in 1983 as part of the design work for the 3000/3500 orebody access shaft.Initial surface blasts indicated a number of significant advantages which were confirmed during the bench and concrete phase of the M37 shaft sink. The application of 'MAGNADETS' was later extended to the horadiam phase of the project.Details of the exploder capacity calculations for the various M37 round designs are included with the paper.

Jan 1, 1985

This paper will discuss Fordertechnik dawatering screens and their application in process industries. Fordertechnik screens were designed for the dewatering of deslimed, wet fines materials encountered in the mineral beneficiation, sand and coal processing industries. However, these screens have also been used in such industries as municipal waste treatment, paper pulp, chemicals and the food industries. Fordertechnik screens are of simple design and, as a result, offer low capital and maintenance costs. The design is based on the use of twin counter-rotating vibratory motors which provide high frequency, low amplitude linear movement of the screen deck which is essential for high production requirements. Fordertechnik dewatering screens are engineered and manufactured in Australia by Mitchell Cotts Engineering under licence to Fordertechnik GmbH of Mulheim, West Germany

Jan 1, 1984

The paper describes the reasons for developing, specifically in South Africa, dense medium processes to allow baths to operate at low (about 1,35) and high (about 2,0) cut points. Low density processing was developed to meet the demand for low ash coals; high density processing was developed to enable heavily contaminated raw coals, destined to be burned in captive power stations, to be de-shaled without loss of combustibles. The anticipated and actual technical difficulties of operating baths at such density extremes are described, and the results from operating plants outlined.

Jan 1, 1987

This paper examines the broader implications of recent and ongoing changes in mineral resource managementå and reporting practices and the impact that these might have on mining companies. It is likely that an International Reporting Code will be developed in the near future, based on a number of National codes produced in recent years. However, this is only part of the reporting story, as an International Code brings with it a range of further issues to resolve. For the Code to be effective, there needs to be international recognition and perhaps licensing of Competent Persons and an expanded base of sponsoring professional bodies. Also, in an increasingly global business, shareholders, regulators and other interested parties need to know and understand the general processes involved in resource and reserve estimation and reporting in order to recognise companies that maintain the highest standards. There is a current trend towards greater scrutiny of company performance in a range of areas under the banner of corporate governance, and many changes are happening that will place greater disclosure burdens on all companies in the future. Good corporate governance means management of company assets for the benefit of the stakeholders. For a mining company, there is no greater asset than its mineral resources and reserves and directors are just as responsible for effective management of their mineral resources as they are for financial good practice. The paper looks at the relevance of corporate governance principles to mineral resource management and the changes that this could bring to the way that companies deal with regulators, shareholders, financiers and others. Finally, increased scrutiny and further regulation inevitably means greater effort by the industry and higher costs. Despite this the author believes that there are substantial offsetting benefits to be gained by companies prepared to take the initiative in improving resource management practices and communicating these improvements to shareholders. In order to achieve the benefits however, the industry needs to fully engage in the changes that are taking place û setting its own standards and working with the regulators rather than sitting back and being legislated against. Mineral resource reporting provides a good model of how this process can work and there will be other opportunities in the coming years as the industry seeks to develop best practice in mineral resource management. The author is an employee of Rio Tinto but wishes to point out that the views expressed in this paper are his own and not necessarily those of Rio Tinto.

Jan 1, 2002

The writer had the pleasure of several months' laboratory tests on a metallurgical process for copper ores devised by Mr. W. H. Corbould, Consulting Engineer, North Queensland. Mr. Corbould's research work in this direction commenced somesix years ago, and he eventually succeeded in obtaining a good extraction of copper and a resulting solution practically free from iron and other impurities. The commercial operation of the process was investigated and special machines with novel features were designed. OUTLINE OF THE PROCESS.The process described in detail in the following pages, required for successful application that the ores contain at least the minimum ratio of sulphur to copper, consistent with the production of sulphadising roasting conditions.

Jan 1, 1921

By Grinenko VA

Mineralogical, chemical, and isotopic data have been obtained for samples from 11 volcanoes and 4 kortlandite intrusives on Kamchatka.Similarities and differences in ore-bearing and barren intrusives are discussed. Differences in sulphide mineralization and sulphur isotope compositions of intrusives are explained in terms of the "auto-sulphurization" hypothesis which involves the redox conditions of the host rocks. possible role for carbon in nickle sulphide ore formation is also considered.

Jan 1, 1990

By Will D. P

A 328 m, 2.4 m diameter raise-bored shaft has been equipped with a modular ladderway system to provide a second means of egress from Aberfoyle's Hellyer Mine in Tasmania. The modular ladderway consists of platforms, ladders and service pipes assembled at the surface and progressively lowered down the shaft. This system provides a rapid, safe and economical non-entry approach to equipping a shaft. The modular construction and single suspension allows for future extension or for reuse in another shaft.

Jan 1, 1988

Modelling of Synergistic Effect of Cyanex 302 and D2EHPA in Zinc Solvent Extraction A comprehensive model is presented to predict the synergistic effect of D2EHPA and Cyanex 302 on co-extraction of zinc and manganese. The experimental results indicated that pH, temperature and the extractants ratio have strong effects on the extraction process. Correlations were proposed to predict the distribution coefficient of zinc and manganese between two phases at different conditions by multiple linear regression. The correlations were simplified by eliminating less important terms by analysis of variance. Optimum conditions (ie pH, temperature, extractants ratio and aqueous to oil phase volumetric ratio) for obtaining maximum separation of zinc from manganese at different zinc concentrations and number of extraction stages were determined. For finding the optimum condition genetic algorithm was used. Comparison the model estimations and the experimental data show that the presented model has good ability to predict the behaviours of zinc extraction system over Cyanex 302 and D2EHPA.

Sep 13, 2010