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Orange Free State Branch Minutes of a Committee Meeting held in the Boardroom of Western Holdings on Thursday, IIth October, 1973, at 5.00 p.m. Present Messrs E. T. Wilson (in the Chair), E. Dunstan, W. B. Evans, C. J. Isaac, C. Mostert, N. Shand, R. Williams, and G. Young.

Jan 2, 1974

By M. Z. Emad, A. Hassan, M. A. Raza, M. U. Khan, S. A. Saki

Digital modelling of a surface is crucial for Earth science and mining applications for many reasons. These days, high-tech digital representations are used to produce a high-fidelity topographic surface in the form of a digital terrain model (DTM). DTMs are created from 2D data-points collected by a variety of techniques such as traditional ground surveying, image processing, LiDAR, radar, and global positioning systems. At the points for which data is not available, the heights need to be interpolated or extrapolated from the points with measured elevations. There are several interpolation/extrapolation techniques available, which may be categorized based on criteria such as area size, accuracy or exactness of the surface, smoothness, continuity, and preciseness. In this paper we examine these DTM production methods and highlight their distinctive characteristics. Real data from a mine site is used, as a case study, to create DTMs using various interpolation techniques in Surfer® software. The significant variation in the resulting DTMs demonstrates that developing a DTM is not straightforward and it is important to choose the method carefully because the outcomes depend on the interpolation techniques used. In mining instances, where volume estimations are based on the produced DTM, this can have a significant impact. For our data-set, the natural neighbour interpolation method made the best predictions (R2 = 0.969, β = 0.98, P < 0.0001).

Feb 6, 2023

By S. Kauvosaari, M. Olofsson, O. Haavisto, M. Kosonen, J. Martikainen

The target in grinding circuit operation is usually to maximise the throughput and energy efficiency while keeping the product particle size on an optimal level for downstream operations. Furthermore, feed ore variations in size and hardness need to be compensated in order to stabilise the process. This is a challenging task for any circuit and requires good instrumentation, combined with careful control design. This study investigates the control of a two-stage iron ore grinding circuit with an AG and pebble mill at LKAB Kiruna KA3 concentrator in northern Sweden. A new control approach based on multivariable model predictive control (MPC) is designed, implemented and evaluated for the circuit. Additionally, advanced instrumentation including a volumetric charge measurement for grinding mills is utilised. The MPC control approach starts with step tests that are used to model the effect of manipulated variables (MVs) like feed rate, water addition and primary mill speed on controlled variables (CVs) such as final product particle size, power consumption and volumetric charge of the mills. In the control implementation phase, the models are then utilissed together with current process measurements and known operating limits to predict optimal future changes for the manipulated variables in order to reach the desired process output values. It is shown that the new control approach improves the stability of the circuit and reduces energy consumption. Keywords: Model predictive control, grinding, optimisation

Jan 1, 2020

By V. Sheikhzadeh, S. M. H. Haddad, M. Saghaeian, N. Esmaeili, R. Hejazi

One of the most significant features of iron ore concentrate (pelletising feed) is the specific surface area (SSA) that affects the achievement of desirable pellet properties. There are various methods to determine this parameters and currently, the most common is the Blaine air permeability method. However, due to the simplified assumptions including spherical and identical particles and 50% bed porosity, the Blain test does not provide accurate results. In fact, these two suppositions are far from reality. In this research, comparison of SSA measurement ways are investigated, containing laser diffraction testing and Blaine air permeability, on samples with different SSA, obtained from Ball mill and high pressure grinding rolls (HPGR). The output data showed that the calculated amounts of SSA by means of laser analysis were far greater than any other one. Furthermore, in the same results of Blaine air permeability tests on samples comminuted by different grinding methods, it was observed that the SSA figures from the laser diffraction method for HPGR products were almost 800 units greater than Ball mill ones. Keywords: Pelletising feed, specific surface area, Blaine air permeability, laser diffraction testing

Jan 1, 2020

By A. Kotze, D. Messina, E. Nagels, Y. Cryns, S. Arnout

The FlashPhos process aims to recover white phosphorus (P4) from sewage sludge by drying, flash combustion/gasification, and carbothermic refining steps. This study evaluates the material behaviour of sewage sludge ash melting and reduction in a refining furnace for the novel FlashPhos process. Thermodynamic modelling in FactSage 8.2 is combined with experiments from a tube furnace to determine the possible phosphorus recovery and minor element behaviour. For the two studied sludges, a yield of 40% and 75% white phosphorus is achieved after 1 hour at 1600°C, corresponding with a 60% and 25% loss to the metal phase. This is slightly above the calculated equilibrium yield of 28%–73%, which depends mainly on the Fe/P ratio of the sludge. Temperature is found to have a significant influence on the final phosphorus yield when leading to incomplete melting of the ash. A clean slag is produced in the process free of heavy metals making it suitable to be used as a cement-like binder material. The main heavy metals that co-evaporate with the phosphorus are Zn, Pb, As, Sb, and Sn. Additional processing steps will be required to remove these to produce a pure P4 product. The metal alloy consists of mostly Fe and P with smaller amounts of other components such as Mo, Cr, Cu, Mn, Sn, Sb, and V. The final slag consists of CaO, SiO2, MgO, and Al2O3 with virtually complete removal of P and heavy metals.

Oct 2, 2025

By John W. Harbaugh, Alfredo Prelate

The goal of the study described here is to develop objective. quantitative methods for estimating the outcome probabilities of exploratory oil wells. The study employs the &apos;re-experience&apos; approach, in which historical data are used in a manner which attempts to recreate the past. Our past experience, of course, is the principal guide to the future. To appraise present-day oil prospects, however, we must analyze prospects that have been drilled in terms of how these former prospects were interpreted before they were drilled. An analysis of how they are interpreted after they were drilled is an inadequate guide to the future because our hindsight knowledge is superior to our foresight knowledge. Objective calculation of future outcome probabilities, then, requires that we attempt to treat past information in a manner analogous to that in which we must treat present information in forecasting future outcomes.

Jan 1, 2014

By Jack Levin

Dr Laurence AlIison Bushel, a former President of the Chemical, Metallurgical and Mining Society of South Africa, now The South African Institute of Mining and Metallurgy, was born in Queenstown on 20th June, 1910, and died in Johannesburg on 4th November, 1991. There were three distinct periods in the career of Laurie Bushel, each enlivened by some special interests or achievements.

Jan 1, 1991

By L. Wade

The University of Nottingham, in conjunction with the University of Kentucky and The Society of Mining Engineers of America, hosted the International Symposium on Underground Mining Methods and Technology from 8th to 10th September, 1986. The programme was based on the central theme &apos;Coal Mining under Adverse Conditions&apos;.

Jan 1, 1987

This Spotlight gives a brief summary of the proposed 1991 tax amendments of relevance to mines and mining houses. It should be read together with the author&apos;s article South African mining tax in the 1990&apos;s&apos;, which appeared in the August 1990 issue of this Journal. A number of tax amendments of relevance to the mining industry were proposed by the Minister of Finance in his March 1991 budget speech. In addition, certain other measures that may be implemented were set out in the budget review document released at the same time. A word of caution is necessary: these measures will become law only if and when they are enacted in the appropriate legislation. When this legislation is tabled in June, it may not contain all of the measures discussed below, some of the measures may appear in modified form, and other measures not discussed at the time of the budget may well appear. Unless otherwise stated, the 1991 tax amendments will affect companies with years of assessment ending in the twelve-month period to 31st March, 1992.

Jan 1, 1991

By M. Grave

Rock Engineers are required to design safe cost effective support systems and stoping layouts for their respective mines. As each stope has its own unique environment, continual re evaluation is required in all stopes to maximize extraction and achieve value from the support standard. This paper presents numerical modelling used to plan early mining within the shaft pillar and a reevaluation of an existing stope support standard.

Jan 1, 2009

By T. J. Otto, I. D. Ungerer, G. C. Lindeque, T. J. van Heerden

Anglo American Kumba Iron Ore (Kumba) continues to implement technologies focussed on improving safety and productivity; this forms part of the groups FutureSmart Mining initiative. The paper provides insights into the implementation of three technology solutions that improves the productivity of heavy mining equipment (HME). Enhancements to the short term mine planning (STMP) process, the effective use of a fleet management system (FMS) and the deployment of drones or Remotely Piloted Aircraft Systems (RPAS) are discussed. The implementation of these and other technologies contributed to a 13% and 22% increase in the overall equipment efficiency (OEE) of the primary HME at Kumba’s Sishen and Kolomela mines respectively. Four key success factors (KSF) are highlighted namely that Kumba’s technology implementation drive is a key enabler to the company’s strategy, has a strong focus on value-add, is underpinned by a holistic and integrated implementation approach and is people-centric.

Sep 1, 2021

By S. Subramanian, L. Mweene

A siliceous low-grade copper ore from Mpanda Mineral Field (MMF), located in south west Tanzania consisting of SiO2 (58.3%), Fe (10.4 %) and Cu (0.9 %) was initially subjected to selective dispersion-flocculation using sodium trisilicate (STS) as a dispersant and xanthan gum (XG) as a flocculant. Subsequently, the selectively flocculated fraction was floated using a collector combination of potassium ethyl and amyl xanthate (1:1) in the presence of poly-ethylene oxide (PEO) as a silica depressant, to get a copper concentrate. The mineralogical investigations confirmed that the MMF ore was mainly composed of quartz, chalcopyrite and pyrite. Adsorption studies indicated that the adsorption density of XG on MMF ore decreased with an increase in pH, while that of PEO was independent of pH. The adsorption isotherms of XG and PEO on MMF ore exhibited Langmuirian behaviour. The zeta potential studies of MMF ore indicated that the iso-electric point (IEP) was located at pH 2.6, presumably due to its high silica content. In the combined presence of XG and STS, the zeta potential of MMF ore became more negative, with an increase in the concentration of STS. However, in the presence of PEO, the zeta potential of MMF ore became less negative with an increase in the concentration of PEO beyond the IEP, without shifting the IEP. Selective dispersion-flocculation of MMF ore improved the flocculated chalcopyrite grade to 19.8 %, yielding a degree of flocculation and a maximum separation efficiency of 12.1 % and 85.7 % respectively, after three desliming stages in the presence of 30 ppm of STS and 30 ppm of XG. A copper concentrate of 29 % grade and 90 % recovery containing silica of 0.9 % grade and 1.7 % recovery was achieved by flotation of the selectively flocculated component, using PEO as a depressant for quartz. Keywords: Flotation kinetics, flotation machines, flotation bubbles, particle size

Jan 1, 2020

By P. Lenegan, R. Masethe, R. I. L. Ferreira

Underground mining in high rock-stress environments can induce unanticipated dynamic rockmass deformation, posing a serious risk to the workforce. Data collected by seismic networks are imperative for the design-as-you-mine process. Often an inappropriate assessment of the seismic hazard is done when unnecessary data are included in analytical techniques, particularly short-term time frames. Depending on the methodology or application of data analysis and interpretation, some of the information may not be relevant and even detract from the objective. By using the spatial event clusters associated with active workplaces to define the shape and size of the polygons for data selection for subsequent analysis, a problematic subjective component can be eliminated. The mining of tabular reefs in South Africa, be they gold- or platinum group metals, is very extensive, and underground workplaces are often widespread. Production stoppages are very costly, especially for marginal mines, so there is just cause not to evacuate an entire operation’s workforce following the occurrence of a large mining-induced seismic event. A rationale based on the damaging peak particle velocities (PPV) of the past seismicity can exclude the unaffected underground personnel and allow a quick orderly withdrawal where required. Micro-deformation may precede rockbursting, which can occur on-shift close to the workface. A mine-wide array of geophones suitable for the accurate location and analysis of seismicity may not be able to detect these higher-frequency emissions. Inexpensive but fit-for-purpose accelerometers, providing real-time, continuous measurement of acoustic rockmass deformation near the workplace, integrated through underground and surface communications networks, are shown to record ‘rock-talk’, clearly distinguishable from the instrument background noise, which can be in the order of hours leading up to an imminent damaging seismic event.

Jan 12, 2025

Termination of membership In accordance with By-Law 7.6.1. of the Constitution of the Institute, the names of the undermentioned members have been removed from the membership register. Colloquium and General Meeting A General Meeting and Colloquium on &apos;Heavy-medium separation and ore sorting&apos; was held on 18th September, 1974, at 09h15, in Kelvin House, Johannesburg.

Jan 12, 1975

Visit to Premier (Transvaal) Diamond Mining Company Limited On the 14th February, 1973, 44 members of the Institute were the guests of Premier (Transvaal) Diamond Mining Company Limited. Metrication News PRESSURE GAUGES There appears to be doubt in some circles about the general acceptance of the pascal (Pa) as a unit of pressure and stress. NATIONAL INSTITUTE FOR METALLURGY / NASIONALE INSTITUUT VIR METALLURGIE REPORT. VERSLAG No. 1430 THE USE OF THE EKCO MINERAL ANALYSER FOR THE DETERMINATION OF COPPER AND ZINC IN THE PRESENCE OF IRON 27th June, 1972 Investigator: Gisela Domel SYNOPSIS The Ekco Mineral Analyser-a portable, radio-isotopic X-rayfluorescence instrument-is briefly described,

By A. Sokolov, M. Demsky, E. Hasikova, V. Gostilo

"Previously, we upgraded and implemented two gamma activation assay (GAA) systems designed to analyse the gold content in raw ores at Zarafshan laboratory, Uzbekistan, and achieved a detection limit of less than 0.05 g/t under actual industrial conditions. Having started to design a fully modern, industrial GAA system for mining companies, this paper analyses the advantages, disadvantages, and special features of all major system components that can influence the sensitivity and accuracy of the analysis. The results of a study to optimize the detector geometry and sample size are presented and the performances of the linear electron accelerator, detector array, and sample transportation system of a modern, industrial GAA system for analysing gold, silver, and rare earth elements are considered. IntroductionGamma activation analysis (GAA) has considerable potential as a future replacement for traditional fire assay analysis in gold mining (Hoffman, Clark, and Yeager, 1998; Morse, 1977; Bourmistenko, 1986, 1981; Sammut, 2016; Tickner et al., 2017). The essence of GAA is to irradiate ore samples with high-energy gamma quanta generated by an electron linear accelerator (LINAC) and then to use a gamma spectrometer to detect the induced activity of the excited gold nuclei. The advantages of this method are discussed in detail elsewhere (Hoffman, Clark, and Yeager, 1998; Morse, 1977; Bourmistenko, 1986, 1981; Sammut, 2016; Tickner et al., 2017), where it is shown that GAA is uniquely suited to analysing ore samples when mining for gold, other precious metals, and accompanying elements.These advantages were realized in three industrial GAA laboratories that were commissioned in Zarafshan, Uzbekistan in 1977, in Magadan, Russia in 1979, and in Batagay, Russia in 1986 (Bourmistenko, 1986; Nii Tekhnicheskoy Fiziki I Avtomatiki, n.d). In 1989, a fourth industrial GAA laboratory was commissioned at a gold mine in Tommot, Russia. However, the project was subsequently halted due to economic reasons (Moshkov and Tjamisov, 2017). Currently, only the laboratory of the Muruntau mine in Zarafshan, Uzbekistan is in operation. The gamma activation method for gold determination is widely applicable at this mine owing to its high productivity and low cost of analysis. An outstanding aspect is the performance of more than one million analyses per year."

May 1, 2019

VISIT TO HENDRINA POWER STATION AND OPTIMUM COLLIERY A visit to Hendrina Power Station and the Optimum Colliery, contractually committed to supply the coal for the power station, took place on the 20th September, 1972. INTERNATIONAL IRON AND STEEL CONGRESS This congress will be held in Dlisseldorf from May 23rd to 30th, 1974. The main theme is "Metallurgical Technology of Iron and Steplml1king".

By John Freer

On 25th November, 1983, nearly forty members of The South African Institute of Mining and Metallurgy, together with Doris Gardner and Judith Money from Kelvin House, travelled by luxury motor coach to Secunda, there to visit the coal-mining and conversion operations of Sasol Limited.

Jan 1, 1984

By J. Arzuúa, U. Castro-Filgueira, L. R. Alejano, F. Malan

"Pillar design for underground mining is typically done using empirical formulae or numerical modelling. Practical experience and recent literature, nevertheless, illustrate the shortcomings of these design approaches. Ongoing monitoring of pillars is therefore recommended to minimize the risk associated with these designs.In a mine where a large number of pillars are cut, different pillar strengths can be expected owing to variations in rock mass strength from area to area. This problem is compounded by the fact that in mining environments the pillars are not always cut according to the prescribed dimensions. Although the original design using either empirical methods or modelling may predict stable pillars, unstable pillars will be encountered in reality. Very conservative designs with large factors of safety may circumvent this problem, but this approach is uneconomical.A possible solution to localized stability problems may be to enhance the strength of a few unstable pillars. It may even be hypothesized that reinforcing a few critical pillars may prevent ‘pillar runs’ on a much larger scale. Rockbolting, strapping of pillars, and pillar shotcreting have occasionally been used in the past as possible solutions. It appears that these have not been successful in all cases and large collapses have occurred in spite of the pillar remedial work.The authors investigated the strapping of pillars by conducting laboratory tests on cabled rock specimens. The results were qualitatively compared to actual attempts of pillar reinforcement available in the literature, as well as additional observations in an old haematite roomand- pillar mine in Spain. Based on these results, the value of steel cabling and mesh wrapped around pillars to improve stability is demonstrated. Some cases where this approach will not be successful are also discussed."

Jan 1, 2017

By F. Navarro, F. Soto, G. Díaz, E. Jélvez, G. Morales, N. Morales

The increasing availability of tools on the web provides a great opportunity for the research community to boost investigation by accessing computational resources from all over the world. For example, data analytics libraries implemented in languages like Python can be accessed through many open and commercial platforms, therefore providing researchers with a common set of tools or shared datasets. Unfortunately, that is not the case with research in resource assessment and mine planning, where the most standardised tools are commercial applications designed to work on the desktop, but there are not many standard platforms for research. As a result, researchers from different groups often need to start from scratch in order to develop their work, and rarely share implementations details. Similarly, apart from a few publicly available examples, there is a lack of common datasets that are validated and can be used to compare results between different approaches. In this paper, we introduce a platform that provides tools for resource assessment and mine planning, which can be accessed remotely utilising Jupyter Notebooks. In its current version, the platform provides (i) definition and implementation of basic structures for managing samples and models (loading, saving, adding or removing columns, etc.), (ii) definition of experimental and modelled variograms for spatial continuity analysis, (iii) definition of standard interpolation methods in resource evaluation (inverse distance and kriging), (iv) definition of standard problems in mine planning (ultimate pit and precedence constrained production scheduling), (v) generation of 2D standard graphs like grade distribution, conditional means, tonnage-grade, and production plans (vi) a set of datasets, which can be used for case studies, and (vii) a set of notebooks with examples and documentation. In this paper, we introduce the platform and show some examples that illustrate some of the possibilities that it has for research and education in the area of resource assessment and mine planning.

Sep 1, 2021