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By L. Ozdemir, B. Asbury, T. G. Rozgonyi

A new type of bit, that has been developed and is being evaluated, shows great potential in expanding the range of rock strength that can be cut by continuous miners and roadheaders. This new style of bit is called the frustum. The tools tested in this program were developed, manufactured and patented by Briese Industrial Technologies, Inc. The frustum derives its name from the unique geometric shape of the cutter, or cutting insert. The frustum shape cutting tool has previously been proven as an effective cutting tool for machining metals, metal matrix composites and polymers. The frustum rock bit has a very dense carbide frustum shape tip mounted on the end of a steel body similar to the conical bits typically used on continuous miners and roadheaders. In between the carbide frustum cutting tip and the steel body there can be a bearing that allows the frustum to rotate around the bit axis. When the bit is forced into the rock at a skewed angle, the frustum tip rotates as it travels. This rotation greatly reduces the cutting forces acting on the bit when compared to the current state of the art conical drag bits. This cutting force reduction, derived from the frustum’s cutting action, allows for much harder and more abrasive rock to be cut without quickly wearing out the bit. Full scale laboratory cutting tests have been performed with the frustum bit in direct comparison to the current state of the art conical bits. Field trials of the frustum bit are currently being planned. Test procedures, results and findings are presented.

Sep 1, 2001

By S. Duma

The main sulphide zone (MSZ) of the Great Dyke is cryptic and without obvious stratigraphic markers. Although there are trends in the dimensions of the PGE and base metal profiles across the Hartley Complex, the profiles are invariant within a particular mining area. Ratios derived from these profiles are used to interpret diamond drill cores drilled ahead of underground development. Detailed logging of oriented core shows the exact position and attitude of intersected faults. Metal ratios are used to estimate fault throw to within 25 cm. It is possible to draw detailed sections showing the extent of ground disturbance well ahead of mining. The method has been confirmed by mining and by drilling inclined holes through the fault blocks. Keywords: main sulphide zone, Hartley Complex, Great Dyke, Zimbabwe, platinum, Palladium, Nickel.

Jan 1, 2004

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

By D. G. Krige

The problem addressed is that of estimating grade differences between sub- divisions of a new gold mining prospect when only borehole results are available. Such differential grade estimates are required in choosing the best area for initial production, and in defining the grade profile over the mine's life for purposes of feasibility studies. It is also often necessary to differentiate between the grades and hence the values of subareas, owned by separate companies, for the purpose of fixing relative share participation percentages in the new mining company. It is shown that exaggerated grade differentials will be obtained from grade estimates of the subareas based only on boreholes within each such subarea, respectively, and that it would be more realistic to apply some 'smoothing', preferably by kriging. This is feasible because the lognormal-de Wijsian model can be used to give an indication of the spatial structure for the boreholes, even where they are spaced far apart; also the degree of 'smoothing' indicated is shown to be relatively insensitive to inaccurate estimates of the relevant semivariogram parameters.

Jan 1, 1987

By El-Sayed M. Sherif, J. D. Comins, Erasmus R. M.

Corrosion of copper in aerated acidic chloride pickling (0.5 M HCl) solutions and its inhibition by 3-amino-1,2,4-triazole-5-thiol (ATT) have been investigated using electrochemical techniques and weight-loss measurements, along with Raman spectroscopy. Electrochemical measurements for copper after varied immersion periods of 0, 24 and 48h showed that the presence of ATT and the increase of its concentration significantly decrease cathodic, anodic, corrosion (jCorr) currents and corrosion rates (KCorr), as well as the dissolution currents at 300 mV vs. Ag/AgCl, while increase polarization resistance (Rp), degree of surface coverage (?) and inhibition efficiency (IE%) to a great extent. Weight-loss measurements after different immersion periods of 6 ~ 48h revealed that the dissolution of copper decreased to a minimum and the corresponding IE% increased with ATT concentration increases. The detection of ATT molecules on the copper surface by Raman spectroscopy indicated that inhibition of copper corrosion is achieved by strong adsorption of ATT molecules onto the copper surface. Aerated acidic pickling solutions; 3-Amino-1,2,4-triazole-5-thiol; Copper corrosion; Corrosion inhibition; Raman spectroscopy

Jan 1, 2006

By B. Geelhoed

A generalization of Gy?s 1979 model for the variance of the fundamental sampling error has been proposed at WCSB2?2005 by Geelhoed. This generalized model can potentially lead to a better correspondence with actual sampling processes. However, a new parameter is required by the new model: ?the parameter for the dependent selection of particles?(Cij). It is important that this new parameter, which is at the basis of the new theory, is well understood in the sampling and blending community. In order to clarify the meaning of Cijand to prevent potential misinterpretation of Cij, we discuss the difference between Cij and an intuitively associated, but different, parameter: ?the parameter for the dependent selection of particle types?(Mij). In this contribution, the theoretical difference between both parameters is clarified. Simulations demonstrate that, numerically, the difference between Cij and Mij can be large. Some additional advantages of the approach which uses Cij are discussed: (i) the approach based on Cijis more general; (ii) in all cases where Mij is known, Cij can be determined as well, while the reverse is not true; (iii) an equation already exists that relates the sample variance to the value of Cij.

Jan 1, 2009

By P. Goosen

The paper presents a basic summary of the approach to hydraulic scale-model tests as may typically be applicable to slurry flow situations. A case study is presented illustrating how hydraulic scale-model tests can be of significant benefit in evaluating the performance of novel or unproven slurry handling equipment. In this case the equipment tested was a fan-shaped expansion piece used to spread the discharge from a launder over the full width of a dewatering screen. The tests showed that the device did indeed distribute the slurry flow both in terms of volume and solids mass, but not perfectly uniformly. Unfortunately the equipment was not taken beyond the model test phase. The scale-model test approach did, however, prove to be very useful as it is considered to have provided a good indication of the expected performance of the full-size unit. Significantly, this was achieved at very low cost compared to the cost of installing the device into the proposed plant and having to later change it out for an alternative or live with the less than optimal performance. The paper illustrates the value that can derive from applying hydraulic scale-model testing techniques to evaluating the performance of new or unusual slurry handling equipment. There is particular value in situations that do not lend themselves to numerical modelling.

Jan 1, 2007

By More-O&apos, R. C. Ferrall, J. W. Wilson

SYNOPSIS The theory of elasticity has been shown to provide a means of determining the stresses and displacements induced by mining in deep level hard rock mines. This theory has been incorporated into an electrical resistance analogue on which the plane of a reef or ore-body can be modelled to enable the rapid determination of stresses and displacements at points in the plane of the reef. This electrical analogue has been used to determine energy release rates caused by scattered mining, which, to some extent, is a measure of the degree of hangingwall fracture. A correlation between predicted energy release rates and actual underground conditions in stopes in the O.F.S. goldfields has been encouraging enough to define parameters on which future stoping layouts can be based. The use of the elastic theory through the analogue has been extended to the assessment of the influence of stoping operations on off-reef excavations. Underground conditions at damaged and undamaged areas have been compared with predicted elastic stresses at the positions under review, resulting in the derivation of design parameters for use in siting off-reef excavations in the prevailing geological conditions in the O.F.S. and Klerksdorp goldfields. The analogue has also been used to assess the vulnerability of certain un mined dykes to bursting. Correlations between stresses induced on dykes by stoping and dyke behaviour underground has enabled critical stress levels to be determined for several persistent dykes occurring in the O.F.S. and Klerksdorp goldfields. A number of long and short term planning projects at mines operating in the Anglo American Corporation and General Mining and Finance Groups are described, where the data derived from the electrical resistance analogue is processed by computer programmes and assessed on the strength of the design factors derived from the correlation of field work and the elastic theory.

Jan 1, 1970

By S. Gqebe, A. Lewis, M. Rodriguez-Pascual

"Gravitational sedimentation of suspensions in various precipitation processes is hindered by colloidal stability. This is due to the high surface charge of the suspension and results in strong attraction/interaction between the ions on the particle surface and counter-ions in solution. Moreover, this strong interaction results in a charge build-up that renders the suspension stable. In order to induce gravitational sedimentation of these particles, a redistribution of ions close to the particle surface is required. We therefore sought to redistribute ions close to the particle surface by applying a magnetic field. This results in the reduction of interparticle electrostatic repulsive forces and a subsequent increase in the zeta potential of a suspension. For the purpose of this study, a copper sulphide suspension was used. Copper sulphide particles were exposed to a range of field strengths for set exposure times and their zeta potential was measured before and after exposure. All particles had an initial zeta potential value equal to or less than –40 mV prior to magnetic field exposure. A significant increase in zeta potential was observed, with values reaching a maximum of –16.5 mV when exposed to a 2 T field strength for 40 minutes. This is due to Lorentz ion shifts resulting from the Lorentz force exerted by the magnetic field on the particle surface. IntroductionMetal sulphide precipitation is a process for treating industrial waste streams with high residual concentration of mixed metal ions and acid mine drainage. This process has been reported to achieve higher metal removal compared with the industrially prevalent lime precipitation, due to the sparingly soluble nature of the metal sulphide precipitates formed. However, precipitation is governed by high levels of supersaturation which favour the formation of fine particles (Lewis, 2010). Consequently, some of the metal sulphide fines formed exhibit slow settling dynamics and thus tend to remain suspended in solution."

Jan 1, 2016

By S. L. Miller

The development of a pilot gold geostatistical ore reserve system proved that geostatistical methods worked well for the routine production of annual ore reserves on gold mines of the Gold Fields of South Africa (GFSA) group, and that the techniques could also be practically implemented, understood and accepted by Survey Department personnel. Many side benefits of the pilot system became apparent, and a variety of useful management information was provided by manipulating the data values that were already captured. It was decided that it was a priority computing project to develop a standard production system (GORS) for routine use by all the GFSA gold mines. Experience with the pilot system enabled detailed functional specifications for GORS to be laid down. These, together with group computing policy determined the terms of reference and constraints for the GORS development. System design could not be finalized until new and appropriate mainframe database software and graphics workstation equipment and software had been found. With these in place the basic system was structured to take best ad- vantage of the interactive features of the workstation, the number-crunching power of the mainframe and the flexibility offered by a relational database and associated 4GL tools. Application sub-systems were developed for data capture, statistical applications, geostatistical calculations, contour plotting and graphical queries. GORS is being introduced to the mines in a phased manner with suitable documentation, training and support structures to enable it to be routinely and effectively used on a day-to-day basis by all group gold mines.

Jan 1, 1987

By G. Iabichino, M. Cravero, F. Nacci, L. Rinaldi, L. Vigliero

ABSTRACT: The proposed paper is aimed at analysing the failure of a steep cliff slope that, in the past, was exploited for open pit mining operations. A volume of over 400,000m3 of gneissic aplitic rock was involved in the slope failure. An evaluation of possible failure mechanisms is given, based on a structural description of the rock mass, a mechanical characterisation and on computation methods. The block theory and limit equilibrium techniques for sliding and block toppling were applied and a comparison is given with the result obtained by using DEM models. RESUME: Le document proposé vise l’analyse des mécanismes de rupture d’une falaise qui a été intéressée dans le passé par une mine à ciel ouvert. Un volume supérieur à 400.000 m3 de aplite-gneiss a été concerné par la rupture de la falaise. Le document fournit une évaluation des possibles mécanismes de rupture, basée sur une description structurale de l’amas rocheu, une caractérisation mécanique et des méthodes de calcul numérique. L’analyse a été développée à l’aide de la théorie des blocs et de la technique de l’équilibre limite, soit pour le glissement que pour le basculement des blocs, et une comparaison avec le résultat obtenu par application des modèles DEM a été effectuée. ZUSAMMENFASSUNG: Die vorgeschlagene Arbeit zielt darauf ab, den Einsturz einer steilen Felswand zu analysieren, an der in der Vergangenheit eine Mine im Übertageabbau betrieben wurde. Der Einsturz betraf ein Volumen von über 400000 m3 an Gneis und Aplit. In der Arbeit ist eine Einschätzung des möglichen Mechanismus angegeben, der zum Bruch geführt hat, und sie basiert auf einer strukturellen Beschreibung der Felsmasse, einer mechanischen Charakterisierung sowie auf der Anwendung von Berechnungsmethoden. Angewandt wurden die Blocktheorie und die Methode der Gleichgewichtsgrenze für das Abrutschen und Kippen von Blöcken. Darüber hinaus wird ein Vergleich mit den Ergebnissen angestellt, die unter Verwendung von DEM-Modellen erzielt wurden.

Jan 1, 2003

By C. -I. Lee

Since the early 1970s, Korea has constructed many large-scale tunnels and underground storage caverns in response to the rapid industrial development. The rock mechanics engineers have accumulated valuable experiences in the area of underground space technologies. But they still face technical challenges in environmental and safety aspects. To discuss those challenges in Korea, a brief engineering description of underground space projects including oil and gas storage, food storage, pumped storage power plant, transportation tunnels, waterway tunnels, and radioactive waste disposal is presented. Mechanical and hydrological stability analyses of the storage caverns in Korea are also introduced. Depuis le début des années soixante-dix, le développement industriel rapide en Corée a entraîné la construction de nombreuses galeries et cavernes de stockage souterraines. Les ingénieurs de mécanique minière ont donc accumulé des expériences précieuses dans le domaine de la technologie de l’espace souterrain. Cependant, ils font toujours face à de nombreux défis techniques en ce qui concerne les aspects de l’environnement et de la sécurité. Pour présenter ces défis en Corée, l’étude présente décrit les projets d’espace souterrain, y compris le stockage de pétrole et de gaz, de nourriture, centrales de stockage pompé, tunnels de transport, tunnels navigables, et évacuation des déchets radioactifs. Des analyses de stabilité mécanique et hydrologique des cavernes de stockage en Corée sont aussi présentées. Seit Anfang der 70er-Jahre, baute Korea in Folge raschen Industriewachstums viele lange Tunnelsund unterirdische Lagerungsräume. Fachkräfte im Bereich Gesteinsmechanik sammeltenwertvolle Erfahrungen über unterirdische Raumtechnologien. Dennoch stehen sie auch heute nochvor technischen Herausforderungen im Bereich Umweltschutz und Sicherheit. Zur Erläuterungdieser Herausforderungen in Korea folgt eine kurze technische Beschreibung der Projekte zurSchaffung unterirdischen Raumes für beispielsweise Öl- und Gaslagerung,Nahrungsmittellagerung, Pumpspeicherwerke, Straßen- und Wasserstraßentunnels, als auchLagerung radioaktiven Mülls. Mechanische und hydrologische Stabilitätsanalysen derLagerungsräume in Korea werden ebenfalls dargestellt.

Jan 1, 2003

By C. Birch, M. Katuruza

"The purpose of this study was to demonstrate unmanned aircraft system (UAS) technology in opencast highwall mapping using the experience at Isibonelo Colliery in Mpumalanga Province of South Africa. In opencast mines, geological mapping has evolved over time and there have been challenges in extracting valuable information from exposed highwalls due to restricted access for safety reasons. A UAS was used at Isibonelo Colliery to conduct highwall mapping, using drone-based digital photogrammetry techniques. A demonstration survey was undertaken during February 2018. The highwall flyover demonstration was planned for two areas (North and South pits) where field control points were placed by the mine survey department. A contractor used a DJI Phantom 4 (Pro) for the highwall mapping. Raw data was processed within 48 hours and a 3D model of the mapped pit area was produced. Further data extraction included obtaining updated weathering and lithological contact elevations and thicknesses for use in short-term planning. The results showed a good correlation between the resource model and the UAS data model. The project was considered a success and highwall flyover mapping and is now standard practice at Isibonelo Colliery.IntroductionDetailed geological mapping is crucial to the understanding of the structure of any mineral deposit. Several mapping methods may be applied depending on the available exposure/outcrop and nature of the orebody; for example, coal deposits typically suboutcrop only, therefore an opencut highwall provides the best exposure for mapping the geology. Mapped information, when incorporated into a resource model (generated from exploration borehole data), improves the understanding of the orebody or coal seam. This research paper focused on the use of unmanned aircraft system (UAS) technology for pit highwall mapping to generate data for updating geological models and avail the latest information to mine planning to improve the short-term plans."

Mar 1, 2019

By V. Korobko, M. Byantogtokh, N. Byambadorzh, V. Bysov

A three-stage operative planning of mining operations in ore opencasts is considered. The hierarchy of monthly-weekly, weekly-daily, daily-shift planning is offered. For the fastest elimination and deviations in problematic situations a level is analysed and weekly-daily or monthly-weekly operative plans are being constantly updated. Operative planning is formulated on information received of preparation and working of mining panels. The electronic maps of these panels are considered for automated operative planning. On the data of the registration of blasthole drillings on a panel, the position of blasthole entry, their depth and the number of a line are determined. The geologist specifies boundaries of ore grades by the bored silt. The qualitative characteristics of ores are determined by the chemical analysis of slime or magnetic logging of blastholes. The missing geologic information is obtained by interpolation on the data of detailed and operational explorations. During working of the mining panel the technologists mark the movement of shovels, associating this movement to blastholes. For this purpose technological attributes are used: when was the blasthole drilled, what drill-rig participated in drilling, what shovel was used and when was it worked? Around each blasthole the zone of its influence is built up. It represents a discrete, elementary volume of ore or waste. The discrete form of the data is most convenient, as it allows step-by-step methods to be employed of the scheduled tasks in many and various combinations. The account panel working technology avoids ‘combination’ explosions. The elementary blocks should be placed in a trajectory of shovel movement and the trajectory can not be arbitrary. It’s determined by the technological rules of extracting and loading of mine mass. In linking to blastholes, the trajectory of shovels is simulated by the sum of step-by-step moving from one elementary block to another. For this purpose a geometrical linkage of blastholes is used. At a railway haulage, or complete mining with truck haulage, the trajectory of movement is a shuttle along the front of operations in the panel. At a selective mining of ores the number of possible directions is limited to three: moving of a shovel by idle running along the front of operations in the panel, frontal pull all the way down of the panel, and withdrawal. The technologically acceptable trajectories of shovel movement are stored for the following estimation and selection of the best. The estimation is carried out on mathematical models with criteria on the method of the least squares of deviations based on preset parameters from the plan, uniform loading of shovels, and mixing of ore at unloading points. The equations of balance type and directive parameters of the plan, as well as technological restrictions of solid and of elementary blocks within the limits of a trajectory are the restrictions of the model. Depending on an industrial situation it is possible to choose one of the predetermined models. The presented technique is used for longitudinal shovel bench at the Erdenet ore-dressing company.

Jan 1, 2003

By F. M. Ramadhan, M. R. Pratama

Monitoring open-pit mine road conditions has become very critical nowadays. There are several benefits to in conducting research on this field such as opportunity to improve truck’s speed which directly influences truck’s productivity. This research aims to provide a semi real-time, and sensors-based automatic road damage detector that predicts the road quality through road damage exact location tracing, road damages auto-classification, and real-time instruction in the form of work order format to mining road maintenance, and repair authorities through mobile apps and maintenance unit’s in-cabin display. It will also provide the maintenance/repair activity performance evaluation via integrated dashboards. The artificial neural network algorithm is applied during the process of data training regarding classifying road damages and severities which resulted in a valid model. The road damage classification model has a precision level of 80.5% in predicting whether the road is damaged or not. Using this approach, we are expecting to visualise a road quality map of all active roads on mine site.

Sep 1, 2021

By K. Sinding

This paper discusses reasons for mining company mergers that have become the fashion, the role of the ?Juniors? and asks what the motives might really be. It examines changes in company concentration over the last 20 years in key mineral segments. Data at different stages of a project are examined to attempt to elucidate the role of the ?Juniors?. Areas for further research are suggested.

Jan 1, 2009

By A. Mitchell

On 25 August 2011, Andrew Mitchell, Lucas Moalusi, and Matthew van der Want of Bell Dewar hosted a presentation on Mining and Communities in Mooinooi, in the North-West Province. The conference was attended by traditional leaders in the North-West Province, officials from the Department of Local Government and Traditional Affairs, and executives from the mining industry. The presentation concerned traditional governance in mining, communities? rights in terms of applicable legislation, and the corporatization of community affairs.

Jan 1, 2012

By K. F. Lane

Mine planning is a complex function and also a vital one. The quality of the planning has a profound effect on the efficiency and the economics of every mining operation. It is therefore important that the function should not be reliant upon only a few techniques but should have command of an orchestra of them. Then the most appropriate can be selected for each application or, if it is advantageous, a group can be employed in concert. This paper introduces peripheral algebra as a set of techniques which should be included in the mine planning orchestra. Its objective is primarily to stimulate more development not only of these techniques but also others of a similar kind which will increase the effectiveness of mine planning.

Jan 1, 1987

By SHM Harkema, MKG Vermaak, D R. Groot

Surface Plasmon Resonance spectroscopy (SPR), combined with cyclovoltammetry, has been successfully used to study the interactions between ethyl xanthate, heptyl xanthate, dithiophosphate and propyl trithiocarbonate flotation collectors and a gold surface. Large, easily measurable responses have been obtained in the potential areas where the thiol collectors are known to interact with gold. The four collector types lead to differing SPR maximum values, with longer alkyl chains resulting in higher SPR responses, and the trithiocarbonate leading to the highest response values. The SPR responses differ considerably from the current density response at very anodic and cathodic potentials. There are indications that thiols might still be adsorbed at potentials as low as -300 mV (vs SHE). Keywords Flotation collectors; thiol collectors; cyclovoltammetry; surface plasmon resonance spectroscopy.

Jan 1, 2005

By J. Preussner, U. Glatzel, R. Völkl, S. Prins, M. Wenderoth

Platinum base alloys are very corrosion resistant and have got a high melting point. Similar to Ni-base superalloys, which are used for jet turbines, the hardening effect of the intermetallic L12Pt3Al phase is used to receive a material that is creep resistant at high temperatures. Chromium is added to the alloy system to stabilize the L12phase down to room temperature. With the right amount of nickel the misfit and shape of the precipitates can be controlled. Various alloy compositions have been melted and analysed. With scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) a microstructure can be observed, which is very similar to the one in Ni-base superalloys. To support alloy development with simulations, a thermodynamic database of the Pt-Al-Cr-Ni system is about to be established. The SEM and EDS measurements provide useful input to the thermodynamic optimization. Also many data from the literature have been used to receive the best approximation. The Cr-Pt binary phase diagram has been reassessed and the latest results of thermodynamic modelling are presented.

Jan 1, 2006