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Two column flotation cells have been installed as single-stage rougher cleaners at Batu Hijau. The objective was to provide additional residence time in the cleaner circuit to maintain maximum recovery during high mill throughput and high feed grade periods. Installation of the columns has allowed the relatively coarse, well-liberated rougher concentrate and the relatively fine, low-grade scavenger concentrate to be treated separately, improving metallurgical performance in the cleaner circuit. Plant results show that the columns produce a high-grade concentrate at an average stage copper recovery of approximately 80 per cent. There is also indication of increases in both overall plant copper recovery and final concentrate copper grade. In addition, the operability and stability of the cleaner circuit has greatly improved.

Jan 1, 2007

By A. Cáceres, L. Navarro, N. Altmann, R. Betinol

Copper concentrate is produced in Chile in the high Andes and transported to the coast for shipping through long distance pipelines. The pipeline and fittings installed have to withstand the high abrasion and corrosion environment of the copper concentrate. To protect the inside tube wall against corrosion, high density polyethylene (HDPE) liner is used. While HDPE liners can protect the steel wall against corrosion, it has also been assumed that the low surface roughness of the HDPE liner also inhibited incrustation caused by calcium carbonate and sulphate deposition. Recent events have indicated otherwise in a couple of concentrate pipelines for which BRASS has provided consultant service. This paper delivers a case study which includes (i) formation of incrustation and adhesion to HDPE liner, (ii) the detection of the incrustation through hydraulic analysis, (iii) the mechanism of removal of incrustation, and (iv) the catastrophic effects of their presence in an emergency situation.

Jan 1, 2007

Orange Free State Branch Minutes of a General Meeting held at the Welkom Mine Canteen on Wednesday, 21st November, 1973, at 4-.00 p.m. Present Mr E. T. Wilson (Chairman) in the Chair, 15 Fellows and Members, 12 Associates, Graduates, and Students, and 11 Visitors (Total 38). Book review Symposium on Environmental Engineering in Coal Mining The 20 papers presented at the symposium cover some 14 subjects related to environmental engineering in coal mines, such as dust, heat, gas emissions, ventilation, noise, and lighting. Competition for students Each year the Institute offers a prize (or prizes should the entries warrant it) of up to Rl00 for the best paper or dissertation on a topic appropriate to the interests of the Institute. A.8. & T.8. Trust The A.S. & T.S. Trust has been formed with the specific object of establishing a worthwhile source of funds which can be used to further the progress of science and technology in South Africa. Nim reports Report No. 1573 A pilot-plant investigation of a flotation model. Report No. 1597 The role of sulphur in the flotation of sulphide minerals. Report No. 1599 The analysis of silicate rocks and metallurgical slags by X -ray-fluorescence spectrometry. Report No. 1607 The analysis of ion-exchange resins by X-ray- fluorescence spectrometry. Report No. 1617 An electronic differential precision thermometer.

Jan 6, 1974

By H. D. Mtegha

Mining is important to the economies of both Tanzania and Namibia. Recently, both nations revised their national mineral policies to ensure future economic benefit. The main difference in the mineral policy-formulation processes followed by the two countries is identified as the degree and timing of stakeholder involvement during the articulation process. In the case of Namibia, the stakeholders were involved from the start in identifying issues and in suggesting policy solutions. In contrast, the Tanzanian process involved stakeholders after a framework had been developed by a task team. The Tanzanian emphasis was on attracting foreign investment into a traditionally state enterprise system of mineral investment and development. One can argue that the policies developed met the initial requirements, and both are, therefore successful, despite the different processes of policy formulation that were used. However, several fundamental questions arise as a result of the two approaches. This paper attempts to answer these questions by providing a comparison of the processes used for developing and formulating the mineral policies of Tanzania and Namibia. It concludes that the Namibian consultative process is perhaps more sustainable in the long-term because of its wider public support. Time will tell which of these policy-formulation processes provides a basis for sustainable economic growth for developing mineral economies.

Jan 1, 2010

By J. O. Claassen

A study was initiated and solutions implemented to address the root causes of a 30%?40% lower than predicted product yield achieved at a Mpumalanga coal mine. A holistic MRTM approach, which focused on improving exploration, geological sampling and analysis, geological modelling, planning, mining, and beneficiation practices, was used. The study indicated that deviations in the planned versus actual yields at the DMS plant were caused mainly by incorrect geological yield predictions, high and variable levels of dilution, and near-dense material, as well as the textural properties of the ore. Keywords MRTM, mining value chain improvement, Witbank coalfields, complex geology.

Oct 1, 2013

"I have been involved in the refractory industry for many years and at some time or another I have designed materials, tested materials, manufactured materials, installed materials, in fact I have done everything except actually chemically analyzed a refractory material.So I would not even begin to tell you how to analyse a refractory material. I'm sure everyone here knows more about chemical analysis than I do.However you could regard me as a customer with and perhaps the insights I have developed may help in putting the role of chemical analysis in the Refractories into perspective.For a start, let's take a step back and ask why we test refractories. The refractories handbook of the American Foundry Association gives four reasons:1. To determine appropriate specification.2. For quality control, to ensure conformance to specifications.3. To provide special property information not available elsewhere.4. For postmortem analysis to determine property changes in service and provideinformation that can point the way to better service.I want to discuss these points with regard to the role of chemical analysis and in particular the abuse of in house chemical analysis facilities. Let me talk first about detelmining appropriate specifications. Most refractory products are made from alumino-silicate raw materials.The phase diagram for alumino and silica is as follows:"

Jan 1, 2014

By W. J. Vlasblom, A. M. Talmon, A. J. Nobel

In initial laboratory tests with a travelling submerged jet on artificially prepared clay it was found that the cavity depth is dependent on the stagnation pressure of the jet and the undrained shear strength of the clay. In addition, it has been observed that the increase in cavity depth with jet pressure is stronger at higher jet pressures. It is assumed that this can be explained by cavitation of the jet at higher jet pressures. At cavitation a cone of bubbles is formed around the jet, which reduces the exchange of momentum between the jet and the surrounding water. This results in a higher jet velocity and a higher stagnation pressure at a specified distance from the nozzle exit. In literature, no relation between the jet pressure of a free submerged cavitating jet and stagnation pressures was found. Additional tests were carried out to determine this relationship. Because practical dredging occurs at relatively large water depths, these tests were performed in a pressure vessel at different pressure levels. It is concluded that the efficiency of a jet (defined as the stagnation pressure at a certain distance divided by the jet pressure), for stand-off-distances smaller than 45 times the nozzle diameter, increases significantly by cavitation in comparison to the non-cavitating situation. However, the jet pressure required for a fully developed cavitation cone increases strongly with water depth. At dredging depths of 20 m and more, the necessary jet pressures are higher than normally applied in dredging practice. Thus in spite of the importance of cavitation in laboratory tests at atmospheric pressure, in normal dredging practice cavitation is of less importance.

Jan 1, 2007

By I. J. Barker

This paper argues that the scale up of furnaces and the supply of electricity are going to be two major issues that will affect the ferro-alloy industry in the near future, and that economic factors will drive this development. The most common type of furnace for producing ferroalloys at present is the submerged-arc furnace with three electrodes, fed from a three-phase AC electrical supply. The scale up of this technology has now reached a fundamental constraint, which is caused by the electrical reactance of the secondary circuit. If the economy of any further scale up is to be achieved in the future then a different technology will have to be used. The supply of electrical power in future is likely to become amore complex issue than it is at present. Existing submerged-arc furnaces tend to run at fairly steady loads, but the ability to swing the load under demand-side management may offer advantages, and may allow a furnace to obtain cheaper power from the organizations that supply this power. This will have to be counterbalanced against the nuisance factors incurred by having a varying load in the operation of the furnace. Various options are therefore discussed in this paper. The possibility of scale up of Søderberg electrodes is discussed, as well as the use of DC power and multiple electrodes. Some of the issues with load swinging are also examined. A particular scenario is also briefly presented to show that considerable further scale up of ferro-alloy furnaces is still possible.

Jan 1, 2011

By T. K. Roy

INFACON XI has no doubt earned the distinction as the first such Congress in India. This prestigious occasion could become a reality of a long cherished dream of the Indian Ferroalloy Producers, consumers and ex-porters. The International Committee of Ferro Alloys (ICFA), South Africa, the august body for organising INFACON, every three years, could be convinced by the Indian Ferro Alloy Producers? Association (IFAPA) to award INFACON (XI) to India. This Congresss, organized by IFAPA, has opened a window for the Ferroalloy Community of India, the up-coming Asian Tiger, to register their strength and weakness to the world forum with the principal objectives of evolving long and short-term optimum road-maps for development. It is to be reckoned that India is poised to be a steel giant by 2020 when it is envisaged that the steel production may reach a level of 120 million tons of which significant proportion has to be in the categories of alloy and special steels, requiring standard and high grade ferroalloys. Keeping the above objective in view, the theme of this Congress has been rightfully designed as ?Innovations in Ferro Alloy Industry.? This Congress has also earned a distinction of more than eighty papers, finally selected for inclusion in the Proceedings. More than 100 internationally and nationally reputed experts in the field of ferroalloys (technology and manufacturing practices as well as world scenario) have been approached for critical review of abstracts and selection for the proceedings. It needs to be mentioned without the cooperation received from ICFA the high standard of INFACON could not have been assured. The papers are suitably grouped under seventeen heads, starting from world situation to production and operation followed by present and future technologies and finally to modelling and simulation. It is a Herculean task to the Technical Committee to fit these papers in proper sequence. The Commit-tee members kept no stone unturned to ensure the cogency with the subject matters and at the same timekeeping the flexibility of interests of the participant, especially in the context of three parallel sessions. The Proceedings containing only refereed papers of high quality, will serve the entire gamut of ferroalloy industry and will also highlight the present status of concerned countries. The areas of attention to make the industries globally competitive and at the same time laying emphasis on the prevailing practices, will help the industry leaders to formulate an appropriate global approach. Following the break-through step, instilled by INFACON XI, the Proceedings will be available both in bound and in searchable electronic CD-ROM format. I, as the Chairman of the Technical Committee would like to express thanks and high appreciation to all the Committee members for their whole hearted efforts in all respects without which it would not have been possible to complete these proceedings in the scheduled time. Technical Committee desires to place on record their gratitude to Organising Committee for their synergic cooperation all through in successfully executing multifarious tasks, associated with such a grand international technical Congress.

Jan 1, 2007

By J. L. Louw

The utilization of centralized blasting systems is progressively becoming a feature of the South African mining industry, owing to increased pressure from the Department of Mineral Resources (DMR) to ensure safer blasting conditions. The purpose of a centralized blasting system (CBS) is to ensure reduced blasting-related incidents and to improve the underground working environment for the mine?s employees. The brief from Samancor Western Chrome Mines (WCM) pertaining to this study was to explore?at a conceptual level?all variables pertaining to the implementation of the CBS. Studies have indicated that Sasol?s SafeBlast? was preferred due to low overall risks and user-friendliness. Empirical observations, however, indicated that attention should be given to the current shaft-clearing procedure and to the installation of additional transformers. This is required to co-ordinate the power supply from 2 level to 10 level with the required supply of the network slave station. A cost analysis indicated that an electronically initiated CBS will result in a R24 cost increase per panel, which relates to a mere 1% cost increase per panel. This cost, in addition to the R1.1 million capital cost, proved to be negligible in comparison to the possible direct and indirect costs incurred by the mine in the event of a blasting-related incident. It was found that Samancor should conduct further studies incorporating the necessary requirements to ensure a successful transition, while considering all stakeholders on the mine. This study proved that the transition to a CBS would ensure safe and efficient blasting at Samancor?s Mooinooi Mine.

Jan 1, 2012

The second annual student prize giving function of the South African Institute of Mining and Metallurgy was held in the Van der Byl Hall, University of Pretoria, on Thursday, 10th March, 1978. The main address (see opposite page) was given by Dr T. F. Muller, Chairman of Iscor.

Jan 1, 1978

PREFACE During the past year, considerable effort was devoted to the implementation of the strategic plan that was adopted by the SAIMM in 1986. Good progress was made in a number of areas, while in others the foundation was laid for future progress. Key Objective of the Institute The key objective of the SAIMM is as follows: To identify the needs of its members and to initiate and give effect to the means whereby the requirements for technology and scientific knowledge of the minerals and metals section of the South African economy are satisfied; and to represent and promote the interests of its members.

Jan 1, 1987

By L. H. W. Walker

As part of an overall design of a computer based mining managerial system, the geological and mineral estates management disciplines find themselves centrally placed in terms of producing fundamental data both before and during the mining operation. Computerisation of all aspects of these fields of endeavour has come to be seen as essential for complete integration with other mining orientated disciplines. Release 1 .l. of the Anglo American system of mineral estates management has been tested and is in the process of being implemented at several Anglo American Gold Division mines.

Jan 1, 1987

By W. T. Ruhmer

Slimes-dam construction in the gold mines of the Anglo American Group by w. T. RUHMER. Pr.Eng.. B.Sc. Eng. (Met.) (Fellow) Current practices generally in accordance with the principles of design and operation of slimes dams within the Gold Mining Division of the Anglo American Corporation are described. Although many of the details given are either obvious or have been amply dealt with elsewhere, these have been included for the sake of completeness. The selection of suitable ground for the deposition of slimes, the initial design and construction of a slimes dam, and its consequent operation are presented in logical sequence. Emphasis is placed on the code of practice for the construction of slimes dams issued by the Chamber of Mines of South Africa, and draft regulations (Water Act of 1956) dealing with pollution. Operating costs are included, and possible future trends are discussed.

Jan 2, 1974

By R. M. S. Falcon, L. M. Falcon

The prediction of the mechanical behaviour of South African coal on the basis of current proximate and other chemical parameters gives rise to problems, and the use of ultimate analyses and inferred maceral and rank analyses, although it has improved the situation to some extent, is still not satisfactory. In an attempt to reach a new level of understanding, this paper gives an in-depth review of the fundamental petrographic characteristics of coal and compares these parameters with the main types of mechanical performance. A two-tiered system of primary and secondary parameters is proposed for the prediction of coal behaviour. The primary or inherent parameters include rank and organic composition. The secondary or extraneous factors include such parameters as mineral mater, cracks or cleats, degree of oxidation, and size. In addition, an explanation is offered of several anomalous behavioural conditions in some South African coals.

Jan 1, 1987

By M. D. G. Salamon

If a transition from one equilibrium state to another occurs during the course of mining, energy transfer takes place in the rock mass, which is assumed to be an elastic continuum. The energy components are defined as follows: the work done by external and body forces, W; the increase in stored energy in the mass, Uc; the strain energy in the rock mined during the transition, Urn; the work done on mine support or backfill, Ws; and the released energy, Wr. The energy balance is defined as (W + Urn) - (Uc + Ws) = Wr> 0, where the first set of components in parentheses represents the sources of energy, while that of the second corresponds to the known modes of energy expenditure and the component on the right is the unaccounted-for energy surplus, which must be released and dissipated in some form. The inequality Wr ~ Urn> 0 applies. Expressions for the energy components are derived first for the general case and then for the 'slit' modal used to simulate tabular excavations. Through specific examples, the importance of the progressive nature of mining is emphasized. The size of the steps used to enlarge the excavations appears to play a significant role in the mode of energy transfer. This observation forms the basis of the second paper in this series of two papers.

Jan 1, 1984

By Lene Hansen

Sulphuric acid plants now and then see unexpected increases in SO2 emissions. Our experience is that it is not always easy for the acid plants to pin point the exact reason for the SO2 increase. Sometimes a catalyst bed is sacrificed even though reliable emperature readings and gas analyses could have verified satisfactory activity, hence the leaking heat exchanger is never discovered and after the shutdown the SO2 emissions are still too high. This paper will look into some basic catalyst management tools: Good record keeping is a necessity for collection of representative catalyst samples, reliable operating data is an inevitable starting point for all analysis and trending of operating data is a must for plant optimisation and troubleshooting. In addition these catalyst management tools will give a continuous updated knowledge of the catalyst status in each bed providing the basis for a more effective replacement strategy. The most typical reasons for increasing SO2 emissions will be presented together with easy guidelines for cross-checking of operating data, temperature optimisation and good record keeping.

Jan 1, 2009

By A. P. I. Popoola

Aluminium AA1200 was laser alloyed with a combination of nickel and titanium diboride using different weight ratios. Chemical reactions took place with the formation of different phases. The characterization of the alloyed surfaces was carried out by x-ray diffraction (XRD), optical and scanning electron microscopes. The alloyed surfaces are composed of the initial phase of Al-Ni dendrites and eutectics of TiB2/Al and TiB2/Ni distributed on the initial phase. Experimental results obtained showed that Al-Ni intermetallics brought about a significant increase in the hardness property of Al; however, these intermetallics are highly brittle and prone to fail by brittle fracture or stress corrosion cracking when put in service. The addition of TiB2 brought about a reduction in the formation of the seintermetallic phases. A microhardness increase of over 10 times the hardness of the substrate was achieved. Keywords Dendrites, intermetallics, metal composite, Nd: YAG laser.

Jan 1, 2011

By M. Pelser, J. Hagemann

"The Anglo American Platinum Rustenburg Base Metals Refiners (RBMR) is the largest producer of nickel cathode in South Africa. It treats slow-cooled matte to recover a platinum group metal-containing magnetic fraction for downstream processing and a nonmagnetic fraction to produce nickel and copper cathode, cobalt sulphate, and sodium sulphate. The refinery was recently expanded from 21 to 33 kt/a nickel. During the ramp-up phase, the sulphur removal section was found to be a constraint to throughput. Nickel hydroxide is precipitated from nickel spent electrolyte by addition of sodium hydroxide, and filtration of the nickel precipitate allows sulphur to be removed from the circuit as aqueous sodium sulphate in the filtrate. The filtration fluxes were found to be limiting the circuit’s capacity. An obvious solution would have been to install additional filtration capacity at significant capital cost and long lead times. RBMR chose rather to first initiate a collaborative project with Anglo American Technical Solutions to better understand the impact of process conditions on filtration characteristics and to evaluate whether the filtration flux could be increased by improving the quality of the nickel precipitate.A deeper understanding of nickel hydroxide precipitation chemistry and kinetics in the context of high nickel and sodium hydroxide concentrations was developed, guided by precipitation theory and confirmed by laboratory tests and plant observations. It was found that the filtration rate could be significantly improved by modifying the precipitate characteristics. A new precipitation process was engineered and retrofitted into the existing plant. Since start-up of the new precipitation system, the available capacity of the sulphur removal section has more than doubled, and control of the process has improved with the better agitation. This paper describes the theory and results used to design the new agitation system, as well as the impact of the change on capital investment, operability, and process efficiency."

Jan 1, 2016

By D. Limpitlaw, A. Alsum, D. Neale

"Ecological footprint analysis (EFA) was first described in 1996 as a measure of carrying capacity appropriated by human activities. EFA is a resource and emissions accounting tool designed to track the demand on the biosphere’s regenerative capacity. Ecological footprints are increasingly used as indicators of organizational and corporate environmental performance and product sustainability. There is a compelling argument to develop an EFA tool for mining companies.To determine the size of a mine’s ecological footprint, land requirements for all categories of consumption and waste discharge must be summed. This land is only made up of the ecologically productive land and water in various classes (cropland, pasture, forests etc.) required on an ongoing basis to provide all energy and material resources consumed and absorb wastes.A challenge in conducting an EFA for a mine is the shortage of accessible data. Undertaking an EFA for a corporation or individual site entails compiling consumption and emissions data (which can be used for other reporting applications). The footprint results themselves highlight the most critical aspects of an organization’s impact on the environment and provide a platform for focusing actions and for educating the workforce to improve their contribution to best-practice operations. This paper discusses the benefits and challenges of undertaking an EFA for a mining company, and provides examples of the various components of ecological footprints associated with mines, as well as showing how an EFA can be used to understand and communicate some of the impacts associated with mining activities.IntroductionFundamental biophysical and economic limits are now being experienced in many countries around the world. Herman Daly, a former World Bank economist, described this scenario as ‘uneconomic growth’, where the costs of growth exceed the benefits (Daly, 2005). This occurs when the economy’s expansion encroaches excessively on the surrounding ecosystem, sacrificing natural capital. Under such conditions the sacrificed natural capital is more valuable that the resulting economic growth. Consequently, the world faces largescale threats to sustainability and especially to the viability and continued existence of the ecosystems that support human settlements (El Zein et al., 2014). In recognition of this sustainability imperative, mining companies are increasingly concerned with their ecological footprint (EF)."

Jan 1, 2017