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By A. Chryssoulis, D. Venter, R. Dunne

An often-overlooked parameter of flotation processing is the impact of surface chemistry. Flotation processing, being a heterogenous process is largely reliant upon the chemistry occurring at the interfaces between solid-liquid phases. Development of analytical techniques such as Auger electron spectroscopy, X-Ray photoelectron spectroscopy (XPS) and low energy electron diffractions (LEEDS) has allowed for a dynamic view characterizing surface composition and structures. The advent of ‘static’ systems, capable of measuring ultra-thin layers on surfaces at low concentrations, was the next step in surface analytical developments. In general, it is the low concentrations and fragmentation patterns which limit the analysis of certain chemical species at plant concentration ranges. At present, analysis of inorganic and organic surface modifiers by time of flight mass spectrometers with a variety of ionization techniques has become a common analytical method to measure chemical species on the outermost surface of mineral particles. By studying the relationship between surface analysis results with metallurgical outcomes, the implications of the presence of surface species can be determined. The presence of flotation activators or depressants can be established using Laser Ionization Mass Spectrometry (LIMS) and Resonant Ionization Mass Spectrometry (RIMS) which are highly versatile surface sensitive analytical techniques. A case study applied to sphalerite flotation in the Neves Corvo Cu-Pb-Zn concentrator and the implication inorganic surface modifiers have is presented. By determining the relative concentrations of Cu, Pb, oxidation products, Ca and other surface species in floated and rejected mineral particles, rationale for improving recovery and selectivity is elucidated. Keywords: Cu-Pb-Zn Flotation, Process Mineralogy, Surface Chemistry, Flotation kinetics

Jan 1, 2020

By A. Angelov, U. Peukerd, S. Gaydardzhieve, A. Stefanov, K. Grossman, V. Stoilov

Flotation concentrate originating from the Asarel-Medet porphyry copper mining and processing complex in Bulgaria has been subjected to regrinding using a Ro-Star mill; the effects of which on the downstream metallurgical behaviour are discussed. Particularly the effect on the liberation degree was studied through an optical microscopy and MLA-SEM automated mineralogy. On the other hand, copper selective flotation of the reground bulk concentrate was realised to evaluate the anticipated metallurgical improvement. Process parameters such as involvement of prior hydrocycloning and variation of collector dosage have been evaluated. Within a two-minute residence time inside the Ro-Star mill, an improved liberation degree of the copper bearing minerals has been observed. As a consequence, enhanced copper recovery and selectivity against pyrite was noted. It has been found that in order to guarantee efficient flotation of the resulting ultrafine particles, a modified flotation regime (i.e. changing collector suite and dosages) should be followed. Keywords: RoStar Mill, liberation, flotation recovery, ultrafine particles

Jan 1, 2020

By H. Rosen

The pump is the heart of most industrial and mining plants, providing the energy to separate valuable minerals from process feed. The actual effect of the pump, both in terms of production costs and overall process efficiency, is often assumed or misunderstood by engineers due to insufficient pump performance data. Pump performance can be understood and corrected, where required, through continuous performance monitoring, leading to dramatic improvements in both pump life cycle costs and system efficiencies. The performance of every pumping application is subject to variation and the main contributing factors are as follows: ?Unavoidable deviations from pump supplier curves ?Pump wear ?Pump curve derating factors for slurry pumping ?System curve variation ?Deviation from basic principles of centrifugal pump operation. These are discussed in detail through case studies and the author?s personal experiences. This paper shows ways to minimize the effect of these variations, thereby reducing performance loss and preventing damage to the pump. The paper discusses the benefits of efficient pump operation, the requirements of pump performance monitoring, and its practical application to pump operation in the slurry and water environments. The cost of remedial actions is explored and compared against the savings in both power and plant reliability, resulting in a reduced life cycle cost of the pump.

Jan 1, 2010

By D. Nardini

The need to move towards faster and safer mine development is a key priority in mining houses globally. In addition to this, South Africa faces an array of challenges introduced by labour-intensive operations; hence a study was conducted to look into improving development rates and labour productivity, specifically in the areas where trackbound flat-end development is required. The aim of the study was to propose a method to deliver fit-for-purpose tracked tunnels that advanced at a rate of one blast per end every single working day. A major part of the study was to optimize the selection of an appropriate trackless fleet and mitigate any constraints introduced with the mechanization. This was done by creating scenarios, based on a typical case study, looking into the aspects around safety, mine design, mine activity cycling, men and machine requirements, service installations, and trackless-trackbound interfaces. The case study was based on a deep-level gold mine developing twin headings with connectings; however, with the move to extend and deepen platinum operations it is foreseen that twin end development will become more prevalent due to ventilation, logistical, and other requirements. With the introduction of the trackless mechanized system suggested, development rates of 56 m of system advance are expected (189 m total development), with on an average of three headings and fixed blast times. Scenarios run with multi-blast conditions yield expectations of 75 m/month advance of the system, significantly higher than the conventional performance seen today.

Jan 1, 2012

By T. J. Otto, C. Musingwini

"The objective of any mining company is to sustainably maximize the net present value (NPV) throughout the life-of-mine (LOM). The expected NPV over the LOM is calculated based on a mine plan, yet the actual value realized by the mining company depends greatly on the level of intertemporal execution against the mine plan. Consequently, a major key performance indicator (KPI) that is often overlooked in open pit mining, due to a greater focus on temporal KPIs, is the degree of spatial compliance to the mine plan. Such focus sometimes leads to short-term actions being detrimental to long-term plans. In this paper we describe the development and implementation of a spatial mine-to-plan compliance reconciliation approach for an open pit mine. Application to a case study open pit iron ore mine in South Africa indicated a significant improvement in the spatial mine-to-plan compliance, from 69% to 94% over a three-year period from 2014 to 2016. These results indicate that implementation of the proposed spatial mine-to-plan compliance reconciliation approach can contribute positively to improving the level of spatial execution and assists in improving the alignment between short-term, medium-term, and LOM plans.IntroductionThe objective of any mining company is to maximize the net present value (NPV) throughout the life of mine (LOM). However, this objective needs to be fulfilled in a sustainable manner that considers the needs of various stakeholders, including employees, shareholders, and local communities where the mines operate. The expected NPV is calculated using a mine plan as a basis. Mine planning broadly involves identifying a strategy to exploit the mineral resource in a way that maximizes value at an acceptable level of risk throughout the LOM (Tholana and Neingo, 2016).The mine planning process is a well-recognized component in the mining value chain of an open pit mine. Figure 1 reflects the relative position of mine planning within a typical open-pit mining value chain from the mineral resource to the market"

Mar 1, 2019

The current global economic climate has adversely affected the resources industry in general. For the gold mining industry, even though the gold price has been stable as compared to other resources, there is still a need to cut costs even further in order to be profitable and sustainable. Of all the costs that are associated with mining, comminution of ore accounts for the majority. Comminution costs constitute mainly electricity, grinding balls and liners. Of these three components, grinding balls form the major portion of the consumable costs, and can be as high as 40%?45% of the total. As a result, proper grinding ball selection is a key consideration towards reducing mining costs. This paper discusses quality control procedures that can be conducted in order to select the best grinding balls for a particular application. Keywords: grinding balls, forged, semi steel, hardness, chemical, metallography, wear testing, impact test

Jan 1, 2009

By P. F. Dicks, N. J. Shackleton, E. H. W. Theron, V. Malysiak

Flotation is a complex physical chemical process in which flotation reagents play a vital role in valuable minerals recovery and concentrate grades. This study examines the performance of new generation AECI Mining Chemicals (previously named Senmin) collectors. They were developed to enhance the valuable minerals recovery and flotation selectivity by tailoring the collectors to target specific valuable mineral species present in an ore and thus create added value for concentrators treating PGM ores. The case study was conducted on a Platreef ore, where batch flotation tests were performed and the concentrates were mineralogically characterised for PGE and BMS using QEMSCAN. Further batch flotation testwork was conducted on Merensky and UG2 ores from various localities in South Africa to confirm the trends observed for Platreef ore. The results have shown that there is a strong correlation between PGE mineral type and AECI Mining Chemicals collector type - clearly demonstrating that one reagent type does not fit all flotation applications. Keywords: Batch flotation, QEMSCAN, collectors, PGE and BMS

Jan 1, 2020

By T. Lee

The mining industry, both here and internationally, is continually developing increasingly sophisticated software to compute mineral resource estimates, but these processes cannot compensate for a flawed geological interpretation of the geology of the economic commodity(s) concentrations. Quality assurance and quality control (QA/QC) is becoming increasingly common in association with the sampling and assaying practices within the industry. However, it is rare in the case of a geological interpretation associated with mineral resource estimation. Why? In the context of this paper, QA/QC relates to the use of statistical and graphical tools to show that the geological economic commodity concentrations have been appropriately domained. Domaining is essential to improve the chance of getting a mineral resource estimate right. Commodity value and acceptable concentration variation within a mineral resource can be ingredients that make mineral resource estimation difficult to get right. But it is possible to get it right a very high proportion of the time. It is more likely to occur when inappropriate data consolidation is minimised. In any case, inappropriate data consolidation is significantly reduced when the geological interpretation is strongly consistent with the data and it is demonstrable. To achieve quality global estimates of geological domain concentrations, it is essential that the geology of the prospect is understood sufficiently that the deposit is appropriately domained. Appropriate domaining occurs when sample populations are separated in such a way that only data in harmony with each other within the population contributes to the domain's concentration estimate. The paper will use four brief case studies to illustrate how QA/QC can be used to display data and validate the underpinning geological interpretation through its associated domaining to get it right when it comes to a mineral resource estimation.

Jan 1, 2007

By A. Golder, S. P. Dandapat, I. Roy

One of the consequences of large-scale opencast mining for coal is the disposal of an enormous volume of overburden material that needs to be removed. With the enlargement of opencast mines and associated high stripping ratios, the volume of overburden extraction is rising. Overburden from the initial mine cut has to be necessarily dumped outside the mining area until enough void is created inside the mine for back-filling operations. The quantity of overburden placed outside the mining area normally varies from 10% to 30% of the total overburden removal. The stability of these dumps placed outside the mining area is of prime importance from the point of view of smooth operations of the mines and safety of persons in and around the dumping area. Owing to increasing pressure on land use, mine operators do not have any other option other than to place the waste dumps very near to the surface edge of the pit, which may lead to failure of the topsoil benches of the working pit. This study identified major controlling parameters that influence a stable but economic combination of height and slope angle of external dumps located close to the edge of an open coal pit.

Nov 27, 2024

By M J. Daniel

The diamond industry is no newcomer to High Pressure Grinding Rolls (HPGR) as it has used the technology for more than 20 years, predominantly in secondary crushing and recrushing roles. In fact it could be argued that the diamond industry has led the way for the wider minerals industry to consider its application. In existing conventional secondary cone crushing applications, large valuable diamonds are" won" through meticulously managing the recovery process within defined particle size ranges. Conventional crushers operate with relatively large closed side settings, but have the potential to damage diamonds by making direct contact with the sides of the crusher. Cone crushers also result in steep product size distributions that run a high risk of losing many of the smaller, unliberated but more abundant diamonds from the rock. This current comminution paradigm of particle size reduction management results in recrushing processing applications or plants where HPGRs are often used.

Jan 1, 2010

By P. Vlasak, Z. Chara

Since the flow behaviour of slurry containing both coarse and very fine particles has not been sufficiently clarified, the paper focuses on the experimental study of the particle size distribution, time and intensity of shearing and the effect of chemical agents on the hydraulic gradient versus the average velocity relationship of fluidic ash slurries in the laminar and turbulent regimes. The recirculation pipe loop with smooth stainless steel pipes of inner diameters 26.8 and 36 mm was used for measuring the ash-water mixtures flow parameters. The dense fluidic ash-water mixtures behave as time dependent non-Newtonian slurries. Shearing, the addition of bottom ash or chemical agents, favourably affects the flow behaviour of dense fluidic ash-water slurries. The hydraulic gradient in the laminar region significantly decreases; also the laminar/turbulent transition region is reached for lower flow velocity.

Jan 1, 2007

DD3-tunnels (PD BH's) ? Rotary coreholes 111no. (124) ? Percussion holes Ono. (37) ? Sampling (rock and soil) ? Soil and rock permeability ? testing ? BH Televiewer Surveys [ ]

Jan 1, 2007

By M. M. Ali, C. Musingwini, R. A. Phillips

The long-term open-pit mine production scheduling problem (OPMPSP) is typically solved in two broad stages. The first stage entails optimisation of the ultimate pit limit, which delimits the economical final pit and maximises the undiscounted value of the deposit. The second stage entails optimisation of the long-term open-pit mine production scheduling, which maximises the discounted value of the deposit. The long-term OPMPSP is a type of an NP-hard problem, such as the travelling salesman problem (TSP), because it is intrinsically complex to solve since it incorporates both hard and soft constraints. Therefore, metaheuristic approaches have been used to find global optimum solutions to the long-term OPMPSP. This paper presents a metaheuristic approach utilising a dual interchange algorithm (DIA) to solve the long-term OPMPSP. The DIA is a parent algorithm which supervises two subservient algorithms, namely, simulated annealing (SA) and Tabu search (TS). The DIA selects the better solution generated in each run from the two algorithms, and simultaneously penalises the algorithm that produced an inferior solution, while rewarding the one that produced a better solution. The DIA was tested on the three-dimensional Arizona Copper Deposit (KD) dataset, which is publicly available for research purposes from the online MineLib repository. It was set to generate net present values (NPVs) in five-minute intervals and the solution improved until it plateaued at about 30 minutes of runtime. The NPVs compared favourably to those obtained on the same KD dataset but obtained over 24-hour runtimes, when solved using simulated annealing and Tabu search algorithms, and the NPV generated from the work of Muñoz (2012) using the modified TopoSort as found on the MineLib repository at the time of this study. Therefore, this paper demonstrates that DIAs can be developed and used to solve the three-dimensional long-term OPMPSP.

Sep 1, 2021

By B. P. Watson, A. Carpede, W. O. Kekana, N. Fernandes, W. Theron, M. P. Mahlangu, G. Betz

The research described in this paper was done to confirm the Upper Group 2 (UG2) PlatMine peak pillar strength formula (Watson et al., 2007), which was determined from a back-analysis of failed and unfailed pillars. Underground measurements were made on a stable pillar that was loaded by firstly reducing it’s length and then by mining the surrounding pillars until pillar failure took place. The pillar was instrumented with suitably positioned strain cells and closure meters, which allowed both the average pillar stress and strain to be determined. The paper describes the methodology applied to identify a suitable position for the instrumentation, as well as the results. A stress/strain curve is presented for a UG2 pillar with a w/h ratio of 2.0, at Booysendal Platinum Mine. The measured pillar strength was similar to the predicted strength using the PlatMine pillar strength formula for UG2 pillars. The PlatMine formula has been successfully implemented on Booysendal Platinum Mine, and about 3 670 pillars have been cut without a single failure. An additional revenue of US$1.3 billion was calculated for the 25-year life of the mine as a direct result of the improved pillar design, given the January 2020 platinum group metals basket price. An extended life of mine and better mining efficiencies will also be realized.

Aug 1, 2021

By M. Seerane, R. Machaka, P. Ndlangamandla

"Metal injection moulding (MIM) is a near-net-shaping powder metallurgy technique suitable for the cost-effective mass production of small and complex components. In this paper, the effects of the metal powder particle size on the final properties of 17-4 PH stainless steel are reported. Three different particle sizes (d50 33.0, 7.91 and 4.04 µm) were used to prepare the injectable MIM feedstocks using a CSIR-developed wax-based binder system at a fixed solids loading of 60 vol.%. The distribution slope parameter and the rheological flow index behaviour were used to predict the flowability of the feedstocks. The effects of the particle size on MIM products were established. The results are discussed in terms of the subsequent microstructural and mechanical properties of MIM 17-4 PH stainless steel against the established MPIF Standard 35. IntroductionMetal injection moulding (MIM) is a near-netshape manufacturing process established as an alternative to produce complex small-tomedium shaped components that were previously fabricated by conventional methods at higher costs (Attia and Alcock, 2011; Todd and Sidambe, 2013).Although recent advances in micromanufacturing (mainly machining and electrodeposition-based) have enabled the fabrication of complex micro-size geometries directly into miniaturized parts, these processes are generally neither routine nor easily accessible at present (Attia and Alcock, 2011).Typically, the MIM process consists of four steps: mixing, injection moulding, debinding and sintering. Mixing involves blending of the desired metal powder composition with carefully selected multicomponent organic binders at the right proportion. This mixture, which is called feedstock, is then injected into a mould of a required shape to form a ‘green part’. Debinding is the removal of the binders by chemical, thermal, or catalytic means while maintaining the shape of the part. Finally, the debound part is sintered to a full or near-full density part (Sotomayor, Varez and Levenfeld, 2010). The MIM process is essentially a combination of plastic injection moulding with conventional powder metallurgy technologies."

Jan 1, 2016

By Ron Tluczek

[Power Point Presentation]

Jan 1, 2006

1. Book review • World mineral statistics 1974 to 1978. Production: Exports: Imports. London, H.M.S.O., Institute of Geological Sciences, 1980. (Reviewer: R. P. King) This edition is the third in a regular series prepared by the Institute of Geological Sciences. It is a useful compilation of statistics on the production, export, and import of fifty-eight different mineral commodities. Each mineral is listed by country, and a table is provided for the annual production, the annual imports, and the annual exports for each commodity included. However, some commodities are treated in considerably more detail; for example, aluminium and bauxite have tables under the following headings: Production of Bauxite, Production of Alumina, Production of Primary Aluminium, Exports of Bauxite, Alumina and Aluminium, Imports of Bauxite, Alumina and Aluminium. The information presented is the latest official information available from primary sources; the compilers have not relied on data from secondary compilations. This publication will be of considerable assistance to all who are concerned with the trading of mineral commodities and their production.

Jan 1, 1981

By A. W. Cramb

A three-day symposium on the production of clean steel organized by The South African Institute of Mining and Metallurgy, was held in September 1995 at Vanderbijlpark. It was attended by 151 delegates, who represented the whole of the steel industry in South Africa: Iscor Works, Saldanha Steel, Columbus Stainless, Highveld Steel & Vanadium, Iscor Research & Development, University of Pretoria, and Technikon Witwatersrand, as well as the users of steel products were represented. Professor Allan Cramb held the delegates attention with well-presented research and practical information. He obtained excellent interaction with the delegates by responding in depth to the questions put to him during the Symposium. In summary, he emphasized the following aspects of the elimination of defects during the processing of steel in continuously cast materials.

Jan 1, 1996

1. Book reviews Dislocations and properties of real materials, edited by M.H. Loretto. London, The Institute of Metals, 1985. 392 pp. Reviewer: F.R.N. Nabarro Au &Ag heap and dump leaching practice, edited by J.B. Hiskey. AIME, 1984. 162 pp. $20 (member), $15 (student member), $30 (non-member) plus $3.50 for postage and handling. (Order from SME Books, Caller no. D, Littleton, CO 80127, U.S.A.). Reviewer: R.A. Snodgrass The cost and availability of Colombian coal, by Eric D. Jamieson, with the assistance of Kathleen Jamieson. London, lEA Coal Research (14/15 Lower Grosvenor Place, London SWl W OEX). £50 (in member countries), £100 (in non-member countries). Reviewer: W.C. Mather Extraction Metallurgy '85. London, The Institution of Mining and Metallurgy, 1985. £42. Reviewer: R.A. Snodgrass 2. Recent publications Mining annual review 1985. London, Mining Journal, Jun. 1985. 600 pp. £26.50 (surface), £39.50 (air). High heat production (HHP) granites, hydrothermal circulation and ore genesis. London, The Institution of Mining and Metallurgy, 1985. 593 pp. £27 (members), £30 (non-members). Potential mineral resources of Egypt. 144 pp. US$10. Available from Bendix Field Engineering Corporation-MPGAP, Box 1237, Grand Junction, CO 81502, U.S.A. 3. Mintek reports Report M212 South African costs of equipment for the metallurgical industry (1984). Report M213 The response of as-rolled 3CR12 steel to heat treatment. Report M214 A computer programme for use in the development of multi-element X-ray-fluorescence methods of analysis. Report M221 Commodity profiles for selected metals. Report MIO7D Upgrading of alaskite rock to feldspathic sand. (First issued Jun. 1983; reissued Nov. 1985). IMM awards Given below are details of the trust funds to which applications are invited for grants, etc., payable in 1986. Application forms, which must be returned to the Secretary before 17th March, 1986, are available on request. Applicants should note that, in general, preference will be given to members of the Institution.

Jan 1, 1986

Report M294 A mineralogical investigation of potential gold-sorbing minerals and shales, by c.T. Logan. Dec. 1986. 12 pp. Computer software The Fifth IFAC/IFIP Symposium on Software for Computer Control (SOCOCO 88) is to be held in J ohannesburg from 26th to 28th April, 1988. Tunneling 88 The Institution of Mining and Metalurgy, with the cooperation of the British Tunneling Society, the Institution of Mining Engineers, and the Transport and Road Research Laboratory, Department of Transport, is pleased to announce the fifth international symposium, Tunneling 88, which wil be held in London, England, from 18th to 21st April, 1988. Ion-exchange processes ION-EX '87, an international conference and industrial exhibition on the industrial, analytical, and preparative applications of ion chromatography and ionexchange processes, wil be held in Wrexham (North Wales) from 13th to 16th April, 1987.

Jan 1, 1987