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By J M. F Clout, E Donskoi

The ability to design a beneficiation process for a new orebody based on particular feed characteristics is a powerful and practical tool. A new technique has been developed where beneficiation outcomes can be calculated by combining feed size-by-size chemical analysis, mineralogy, liberation and particle characteristics with a series of simple theoretical unit separation models rather than a simple mass balance approach or an exhaustive beneficiation test program. The new technique provides the ability to rapidly identify ore types that have the potential to meet product specifications whilst also rejecting others that will not meet specification even if a perfect separation was achieved. Beyond the broad scale decision making process, practical mineral separation curves from actual plant data can be used to more closely simulate the proposed process. This approach reduces the amount of laboratory and pilot plant work necessary by targeting what process stages will be required, increases early rejection of uneconomic options, identifies problematic ore types or unit operations and is a step towards estimation of final grade and recoveries achievable in potential circuit configurations.

Jan 1, 2004

Population growth, social inequality, pollution, global warming, poverty, overexploitation of natural resources and biodiversity loss, are a few examples of the many challenges facing the world today. Sustainable development is about meeting these challenges and improving the standard of living for the benefit of the maximum number of people. These issues concern governments, communities, environmental and social action groups and individuals all over the world. Business too, has a fundamental role to play in delivering sustainable development. In particular, sustainable development is becoming increasingly recognised as a critical issue for the oil and gas industry to address and act upon. BP is committed to positively respond to the challenges posed by the objective of sustainable development.

Jan 1, 2002

By R Sterk, B Reid

The Konongo Gold Project is located on the western margin of the 125 Moz Ashanti Gold Belt in Ghana, West Africa. It is situated 60 km along strike of the world-class mineral system at Obuasi and is interpreted to lie on the same controlling regional shear system.The project is operated by Signature Metals, a subsidiary of the Liongold Corporation, and is managed and funded by the Liongold Corporation.Historic underground operations at Konongo produced 1.6 Moz Au at a head grade of 11.8 g/t Au, from eight operations spread along 16 km of the shear system. Mining focused almost exclusively on free-milling gold in quartz, ignoring the gold-bearing sulfide mineralisation associated with the quartz veins. Underground mining ceased in 1986.In 2013, Signature Metals re-focused the program at Konongo to assess the viability of mining the sulfide ore sustainably. This led to the first campaign review of the historic underground data and resource potential since mine closure. The Obenemase mine was the first of the eight operations to be assessed as part of this campaign.Large amounts of legacy data have survived for Obenemase and several historic resource estimations have been completed based on these data. The data typically consisted of hand-drawn sections and plans, and ledgers of commonly incomplete drilling and sampling data. Some drill core have been lost over time, but a large amount of quarter-core and half-core as well as pulps and rejects are still available. Previous resource estimates had a low confidence value because all the available assay and geological data were integrated effectively with the estimates, resulting in a lack of understanding of both grade and geological continuity.This project built a new geological model for Obenemase that greatly enhances the understanding of the controls on mineralisation using a thorough approach of re-surveying, re-cataloguing and re-logging. This model led to an increased degree of confidence and a subsequent upgrade of resource classification, and created several previously unrecognised strong exploration targets. The resulting resource estimates increased the value of the project by 100 per cent.This paper emphasises and highlights the importance of a well-understood geological model on the confidence of a resource estimate and how this may directly impact on the project’s ‘bottom line’.CITATION:Sterk, R and Reid, B, 2014. The Konongo Gold Project, Ghana – an example of how geology makes all the difference to a resource estimate, in Proceedings Ninth International Mining Geology Conference 2014 , pp 467–476 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By A H. Clemens, T A. Moore

This paper discusses a number of technical issues related to marketing coal. It outlines how the results of research undertaken in New Zealand and overseas can help producers address a range of technical factors that impact on production costs and marketability. The paper also discusses trends in coal utilisation for power generation and how new technologies may require coal with different characteristics. Research and development into options for CO2 sequestration are discussed including carbon storage in forests, and removal of CO2 from flue or fuel gas in power stations, and its disposal.

Jan 1, 1997

By L O. Filippov, Q Dehaine

Variographic analysis, a classical tool from the Theory of Sampling (TOS), can address practical situations with multiple variables; however, its application has very often been limited to one variable at a time. Recent developments have shown the benefits of using multivariate approaches for variographic characterisation of a set of variables instead of considering individual variables sequentially. Among these approaches, the multivariogram has been revealed itself to be a powerful tool when the overall time-variability of a process must be summarised in terms of a large set of properties (variables) to assess its true global variability. However, even when choosing the properties of interest carefully, the resulting global variance obtained with this approach may be very high. In particular, some variables that contribute to a major proportion of the global (multivariate) variability could be less important for the process performance than others having a lower variability. To address this issue, a new approach is proposed, combining the multivariogram with process modelling and multivariate data analysis methods such as partial least squares (PLS) regression from chemometrics. An example from the mineral processing industry is presented, for which the process performance could be linked to key process variables (sensor data) using the PLS regression. Once introduced in the multivariogram equation, PLS model parameters (loading-weights or regression coefficients) can be used to weigh the variables according to their relevance for the process. In addition, this also permits characterisation of process performance variability with time using only the process input variables and a weighted metric according to the PLS regression model. Ultimately, this method helps to find an optimised sampling procedure in terms of frequency, sampling mode and number of increments according to the actual overall process performance. This approach has potentially many applications in the mining, feed and food, pharmaceutical or any other industry for which it can be used to reduce risks and ensure a better use and management of resources.CITATION:Dehaine, Q, Filippov, L O and Glass, H J, 2017. Optimising multivariate variographic analysis with information from multivariate process data modelling (partial least squares regression), in Proceedings Eighth World Conference on Sampling and Blending , pp 381–390 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

Over recent years the trend in Australia has been towards the definitions of sustainable development which emerged from the 1992 Rio Summit of retaining a commitment to ecological integrity, but also incorporating social and economic dimensions of sustainability. Sustainable development may be seen as maintaining and enhancing:natural capital: defined as all natural resources, both environmental and those of traditional economic value; manufactured capital: made by human kind; including produced goods, infrastructure and built environment; human capital: defined as the health, well-being, intellectual capabilities and spiritual welfare of individuals; and social capital: defined as social relations and institutions within and between societies, their norms and functionality (Ameef, 2002). This paper will endeavour to assess the challenges and opportunities facing the professionals and their Institute in the minerals industry in Australia because the MMSD Global and Regional Australia Reports do not, in the authorÆs opinion, adequately address the æhuman capitalÆ input into the current or future development of the minerals industry, in particular, the sustainability of the professionalsÆ skills, knowledge and experiences in a global context.

Jan 1, 2002

By B Rosemberg, F Lemos, A J. B Dutra

The chemistry of cyanide solutions is complex, this complexity being responsible for the ability to act as complex-forming agents in metal dissolution processes, among them gold and silver. Such ionic species are used in hydrometallurgical processes, in particular in gold extraction and electro-plating. Due to the high toxicity of cyanide, the discard of effluent from processes and/or industries demands rigorous treatment so as to minimise its concentration. Among the conventional chemical treatment of such effluents one can mention SO2/air; biological degradation; oxidation by using hydrogen peroxide; oxidation by sodium hypochlorite, etc. However, the electrolytic recycling process is also promising for cyanide recovery and offers the possibility of recycling it to the aforementioned industrial processes. Such a process does not use additional chemicals but enables direct re-utilisation to the main process aiming at adjusting the cyanide concentration.

Jan 1, 2002

By D Misra, R Ganguli, S Bandopadhyay

The objective of this paper is to assess the accuracy and applicability of recent state-of-art methods such as the machine learning algorithms (MLA) for mineral resource estimation. Conventional methods such as geostatistics have been predominantly used in the mining industry for this purpose with varying success. Recent advances in the use of MLA have provided a fresh approach to obtain improved accuracy in the estimation of mineral resources. Two MLA methods: the neural network (NN) and the support vector machine (SVM) have been used to estimate a polymetallic ore deposit in Alaska.The general characteristic of SVM and NN emphasises the fact that they can approximate any multivariate non-linear relation among variables. Although neural network models are able to capture the nonlinear spatial relationships that may be present in the data, they are usually difficult to optimise under sparse data settings. Of the various NN alternatives, despite their effectiveness, the model selection and estimation process is typically difficult as it involves solving complex integration and optimisation of parameters. In support vector modelling (SVM), estimating of parameters involves optimisation of a convex cost function. The working principle of SVM makes it robust against noisy and extreme value data. At the same time, it can capture the spatial distribution of ore grade more effectively with careful modelling and selection of SVM parameters.The outcome of the MLA methods were compared to those of the geostatistical ordinary kriging (OK) application to study their generalisation ability. The comparison was made using the following goodness of fit criteria: mean-squared error; mean absolute error; mean error; and coefficient of determination. The results indicated that the MLA methods may improve the predictability of ore deposits and thereby reduce the inherent risk in mineral resource estimation.

Sep 26, 2011

By R G. Richards

The Australian glass sand industry produces some 2.8 million tonnes per annum of silica sand, of which about 2.0 million tonnes are exported and the rest is for the domestic market. Approximate production rates for each Australian state are listed. The variety of processing methods used in the currently exploited deposits reflects the size, location, and characteristics of the various deposits and the requirement of the end market/s. The industry uses to a large extent equipment developed for the separation of mineral sands, particularly as it applies to low grade heavy mineral deposits, where low cost, high capacity and metallurgically efficient equipment has proved eminently suitable for the production of the low value glass sands. The requirements of the domestic market, as well as those of the present and potential export markets are discussed covering quality requirements, distribution channels and other factors critical to success.

Jan 1, 1990

Although cyclones have been around in their current form since the early-1890s, there have been some exciting new developments, which have extended their efficiency/operation. These developments have taken place with both dense medium and classification cyclones. The more noteworthy developments are:Inlet designInlet design is the determining factor in classification cyclone capacity and efficiency. The recently developed ribbon inlet with patented pressure bulge has not only resulted in unbelievable increases in capacity, but also in efficiency. Sharpness of separation corresponding to an alpha value of greater than four has been achieved! Secondary offtakeOne of the factors leading to reduced cyclone efficiency is the presence of coarse particles in the cyclone overflow. The secondary offtake has been developed specifically to scavenge these particles from the cyclone overflow with great success. Water injectorThe other major factor resulting in reduced cyclone efficiency is the presence of misplaced fine particles in the cyclone underflow. The water injector, which has been around for many years in various forms, can reduce this short circuit fraction by up to 50 per cent. 3-in-1 cycloneThe 3-in-1 cyclone combines the inlet design, secondary off take and water injector into a single unit resulting in the most efficient classification cyclone available in the market. The RejectorTMIron ore has a high yield to underflow and traditional dense medium cyclones have always been spigot constrained. The Rejector TM is an exciting new development whereby the spigot capacity has been increased substantially. The application of the Rejector TM will result in fewer/smaller cyclones being required for a given duty resulting in efficiency gains and reductions in both operating and maintenance costs.

Jan 1, 2002

During an eight month period, January to August 1978, nine bore holes were drilled in the Mikonui River gravels. On account of two rebores required from near bottom, the number of bores is in effect 11. Just on 1300 feet were drilled with an average depth of 120 feet. Depth varied from 102 feet to 133 feet. Penetration on average per hole value, varied from 7.4 to 16.4 feet per day. Gold values were even more erratic. Drill rig used was the Keystone churn drill manufactured locally by the Dispatch Foundary. It is skid mounted and requires a crew of two persons.

Jan 1, 1979

I want to explore whether it is valid or even useful to talk about sustainable corporations. After 20 years of focus on sustainable development, the concept of a sustainable corporation is not particularly helpful and it may in fact be profoundly misleading. Why? û because it obscures the need for corporations to be recognised as part of a sustainable society, rather than achieving some kind of corporate nirvana divorced from the social, political and environmental reality. It is more helpful to ask whether corporations are ready to recognise that they are one player among many within society û with the demands this would place on them in terms of transparency, accountability and social responsibility. The achievement of sustainable development has become the new corporate orthodoxy of many large corporations. It has become a clichT to argue that corporations must become æsustainableÆ. The achievement of æsustainabilityÆ is encouraged, as the ultimate step in some form of corporate evolution. We are failing to recognise that sustainability a process û not an end in itself. An enormous array of instruments is being developed to measure when sustainability is or is not being achieved. For example, corporate reporting has burgeoned into an art form, which describes æsustainabilityÆ in a variety of ways. There is no external standard applied to such reporting. These descriptions are quite partial and often place the best possible gloss on the companyÆs activities. I have become increasingly uneasy about this rhetoric and this paper has allowed me the luxury of sorting out my unease. I will discuss, largely in the Australian context, the current debate and literature and describe the way some global mining corporations are dealing with these questions, and finally, offer some suggestions which might be helpful at the operational level.

Jan 1, 2002

By S Jokanovic

At New Zealand Steel MiningÆs Waikato North Head operation a Bucket Wheel Excavator û shiftable conveyor mining system is used to excavate titanomagnetite bearing sand and clay. The system utilises two Bucket Wheel Excavators and two Beltwagons with a two shiftable bench conveyors and two common trunk conveyors to deliver material to a processing plant. The original system was commissioned in 1984 as a high capacity, low cost method of excavating. In 1996 a second Beltwagon was purchased, increasing the flexibility of the mining system.

Jan 1, 2002

The overwhelming weight of scientific opinion indicates that human activity is having a discernible and negative influence on the earthÆs climate system. The Australian Government, together with about 100 other nations, has accepted the findings of the Intergovernmental Panel on Climate Change third assessment report, released in 2001. This report was prepared by several hundred eminent scientists from all over the world, from various scientific disciplines and with differing opinions on global warming. The IPCC third assessment report contains a series of relevant, significant conclusions; for example, it finds that there is an increasing body of observations that gives a collective picture of a warming world and other changes in the climate system. Global average surface temperature increased over the past 100 years by about 0.6¦C. This may not seem much, but in the 900 years beforehand, the EarthÆs temperature remained relatively stable. The 20th century was the warmest of the past 1000 years in the northern hemisphere (there is much better information available from the northern hemisphere than the southern hemisphere). The 1990s were the warmest decade of the millennium in the northern hemisphere and 1998 was the warmest year. Although many factors influenced the EarthÆs climate, scientists are confident that greenhouse gas increases were the main factor contributing to global warming in the last 50 years of the 20th century. Increases in carbon dioxide, methane, troposhperic (lower atmosphere) ozone, halocarbons and nitrous oxide have all contributed to global warming. Combating climate change cannot be done without the cooperation of industry and the community at large. It is important that Government and industry work together to achieve greenhouse gas abatement while ensuring continued economic growth. The cause of the problem û the generation of greenhouse gas emissions û lies at the heart of the structure and size of modern economic activity. Greenhouse gas emissions are embedded in our way of life from our energy consumption patterns to the basic production of food. Moreover, the costs of the impacts of climate change to the earth will be potentially revolutionary, not merely evolutionary. It is in this light, acknowledging both the seriousness and nature of the problem before us that I want to reflect on the key drivers in the international climate change negotiations. A consideration of the past, present and future from what I see as the mid-way point in the process. In 1997, Parties agreed to adopt the Kyoto Protocol, which sets out mandatory targets for greenhouse gas emissions for developed countries.

Jan 1, 2002

Generation and Attachment of Submicron Size Bubbles to Colloidal Solids

Sep 13, 2010

By M Rattenbur, A B. Christie, S C. Cox

A new minerals initiative to increase the level of understanding of New Zealand's mineral resources and to promote the development of minerals began earlier in the year in a partnership pilot-project between Crown Minerals and the Institute for Geological and Nuclear Sciences (GNS). The project aims to gather a set of comprehensive geoscientific data and build a series of digital GIS packages to highlight New Zealand's mineral prospectivity. The pilot study was carried out at a regional scale, and is focussed on mesothermal gold mineralisation in the South Island. A significant amount of geological data and information was sourced from open file technical reports held by Crown Minerals and from various databases held by GNS and has now been compiled into a single GIS dataset, which will soon be made freely available to interested parties. In addition to this comprehensive data compilation, prospectivity modelling using Weights of Evidence techniques was undertaken to highlight those areas likely to contain ore deposits. It is clear from this study that the South Island of New Zealand remains highly prospective for mesothermal gold mineralisation. Many of the highly prospective areas, which also contain historic mine workings, remain open for exploration. The study not only highlights these areas, but also other areas where the potential for similar mineralisation exists, in all likelihood with no surface expression. The study has also highlighted the value of many of the open-file technical reports held by Crown Minerals and the need to carry out additional studies using this and other available data at a more detailed level, possibly as the basis for a web-based minerals information system.

Jan 1, 2002

South Africa has joined the league of other major Western World countries by officially adopting its own code for public reporting of Mineral Resources and Mineral Reserves. The recently published South African Code for Reporting of Mineral Resources and Mineral Reserves (SAMREC Code or Code) (SAIMM 2000) is presented here in its local and global context. The main aspects of the Code are listed and elaborated upon. The Code has been written with the participation of the major South African stakeholders in the field including Government institutions, the legal confraternity and the mining industry. Relevant foreign organisations, such as the Australasian Joint Ore Reserves Committee (JORC) and the United Nations contributed to its compilation, and supported it. The Code thus enjoys endorsement both locally and, to a large extent, overseas. The Code is modelled on, and is 90 per cent compliant with, the Australasian Code for Reporting of Mineral Resources and Ore Reserves (JORC Code) (AusIMM, 1999). The paper also elaborates on the duties and responsibilities of Competent Persons signing off resource and reserve reports and on the new listing requirements of the Johannesburg Securities Exchange (JSE), formerly the Johannesburg Stock Exchange, which has officially adopted the Code.

Jan 1, 2002

Hydrometallurgy has a history of over 300 years with copper leachingand cementation having been exploited in Spain as far back as 1670.Since then, hydrometallurgy has become an integral, expanding branch of extractive metallurgy. This paper reviews major developments in hydrometallurgy over thepast century with emphasis on recent commercial developments and their impact on the mining and metals industries. The environment in which these developments has taken place has changed significantly in the past two decades and many factors, often non-technical, have emerged as constraints on the operation of existing plants and the expansion and development of new hydrometallurgical operations. Finally, a number of possible new developments that will shape thefuture of hydrometallurgy in the new millennium are discussed,particularly as they relate to the assimilation of technical advances in other areas of science and engineering. The impact of current trends in the education of hydrometallurgists and the provision of research in support of these future developments is also addressed.

Jan 1, 2001

The pressure of low commodity prices forced the design process for the second lift of Northparkes E26 Mine to adopt a continuous improvement philosophy. The emphasis was to minimise capital expenditure while still maintaining the excellent low operating costs achieved on Lift 1. Although the first block cave lift at Northparkes is the most productive underground mine in the world and is held up as a benchmark for the use of technology in mining, areas for improvement were identified. Every area was critically assessed and investigated for the possible application of new techniques and technologies. Key learnings from the construction and production phases of Lift 1 were captured, documented and used as the starting point for the Lift 2 design. This paper shows how and why the design parameters initially used onLift 1 were changed to become the current E26 Lift 2 developmentproposal. The main differences between the two block caves arehighlighted. The alternative techniques and equipment that wereconsidered are also discussed. * Originally published in the Proceedings of MassMin 2000,published by The AusIMM.

Jan 1, 2001

By W T. Yen

Pyrrhotite crystallises as either a hexagonal or monoclinic structure, both of which can occur in ore deposits. In general, pyrrhotite is not considered as a valuable mineral unless it contains considerable amounts of other metals like nickel or copper. In fact it causes numerous problems in flotation including intensive oxygen consumption, which results in poor selectivity among sulphide minerals in the processing of complex sulphide ores. Also, because of its high sulphur content, pyrrhotite is a major contributor to environmentally detrimental sulphur dioxide (SO2) emissions from smelters. Pyrrhotite also interacts galvanically with grinding media via electrolyte species present in the flotation pulp, resulting in media corrosion. The most effective way to reject pyrrhotite is through a separation stage, which may be difficult when both types of pyrrhotite are present in the ore. In this regard depression of pyrrhotite through a flotation stage may be applied. Pyrrhotite depression by either intensive oxidation or by using sodium cyanide has been practiced. Results present in this work show that NaCN can depress pyrrhotite effectively when combined with an alkaline environment and low collector concentrations.

Jan 1, 2002