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The unpaved road network on a surface mine is extensive, comprising numerous roads of varying construction and material qualities with highly variable traffic volumes. Existing haul road maintenance management systems (MMS) work well for predictable traffic volumes, but for complex mine road networks, the MMS becomes onerous. This results in sub-optimal road maintenance strategies with the attendant increase in total road-user costs and reduction in service. A real-time maintenance management system was thus sought to overcome the deficiencies of existing MMS for mine roads. Since most large mines operate trucks with on-board diagnostic data collation, linked through a centralized communication and GPS backbone, it was proposed that road condition could be monitored on a real-time basis through on-board vibration signature analysis. The aim of this paper is to present the development of a real-time mine haul road maintenance management system. Following are view of mine road maintenance practices, the real-time system architecture is introduced and the results of a field trial of on-board vibration signature assessment is presented. The trial results are discussed in the light of road defect signature recognition, analysis, signature repeatability and system limitations. This approach has applicability to other situations such as a network of district roads, subject to an analysis of the economic feasibility. The paper concludes that modern technology has the potential to apply maintenance as and where needed with possible reductions in authority cost and an improvement in service provided for the road user.

Jan 1, 2003

By R. L. Pienaar

Paper written on project work carried out in partial fulfilment of B Eng (Min. Eng.) degree A study was conducted to investigated and compare the feasibility of two single level extraction layouts for an intact part of theorebody of the De Beers diamond mine, Koffiefontein. Two layouts were chosen and the tonnage profile, development schedule and production ring blast layouts were calculated by applying the information acquired through a literature study. Current principles used on the mine were also applied. The first layout chosen is described as a simple straightforward layout with 6 production tunnels spaced 15 m apart, and is referred to as Layout A. The second layout, named Layout B, is described as a complex chevron layout with 9 production tunnels spaced 15 m apart. This layout has a rim tunnel situated in the kimberlite ground, which is called a chevron and this made the layout more complex than Layout A. By comparing the financial results of the two layouts, it was found that Layout B is a more feasible option than Layout A. Sensitivity analyses show that both layouts are extremely sensitive to the revenue of the projects. Therefore it is recommended that Layout B can prove to be a source of additional tonnage to add to the total tonnage profile of the mine and to extend the life of mine by 20 months, only if certain financial/economic factors improve. There is, however, still some areas of the project that need to be investigated.

Jan 1, 2006

By A. Z. Toper

This is a sampling of the papers presented at the conference, the proceedings can be bought from the SAIMM An extensive research programme to address the issue of rockburst control has been undertaken over a number of years. This paper discusses the development of preconditioning techniques to control face bursts, for safer mining in seismically hazardous areas. Preconditioning involves regularly setting off carefully tailored blasts in the fractured rock immediately ahead of a mining face, so as to encourage slip on pre-existing fractures, in order not to allow the accumulation of high strain energy density in the rock mass. Two different preconditioning techniques have been developed, namely face-perpendicular preconditioning and face-parallel preconditioning. Both have prevented face bursting in areas to which they have been applied, even though several large seismic events have occurred close to the faces in some areas. In addition, minimal overall damage was observed in the preconditioned panels following these events, compared to similarly exposed unpreconditioned panels. Preconditioning has also provided some protection to the face area from distant events, through the capacity of the preconditioned ground to absorb energy. An improvement in hangingwall stability and productivity has also been noted in preconditioned areas. In order to determine the optimum blast parameters for achieving the most effective preconditioning, an extensive optimization study was carried out for the face-perpendicular preconditioning technique. While optimum values for parameters such as hole length, diameter and spacing were determined, it was ultimately concluded that the differences in results obtained by varying the preconditioning parameters were less significant than the clear positive differences observed when comparing preconditioned areas with non-preconditioned areas.

Jan 1, 2000

By G. Westcott

Impala Platinum, the second largest platinum producer in the world, is embarking on a major expansion strategy to increase its platinum output from 1.95 moz to 2.8 moz by the year 2008. The smelter complex, situated in Rustenburg, will undergo substantial modifications, and will require a solution to the capture and treatment of the smelter off-gases and dust produced during smelting and converting operations. One of the solutions explored was an integrated approach, where all the off-gases from both the primary smelting electric furnaces and the converter operations are routed to a large central gas cleaning and double catalysis, double absorption acid plant. In-line sulphur burning, utilizing a highly flexible LURO1spin cup burner with a turn down ratio of 50%, ensures that the acid plant operates independently of operating conditions at the smelter complex.

Jan 1, 2007

By A. Rejeb, A. Millard

ABSTRACT: An evaluation of the importance of the thermo-hydro-mechanical couplings (THM) on the performance assessment of a deep underground storage design has been made as part of the international DECOVALEX III project. It is a numerical study that simulates a generic repository configuration in the near field in a granite medium. The thermo-hydro-mechanical evolution of the whole configuration is simulated over a period of 100 years. The model used to represent the unsaturated behaviour of the various porous media makes allowance for moisture transfers through the effect of thermal and water gradients. The paper presents a comparison of the temperature, water pressure and stress fields obtained by TM, TH, HM and THM coupled calculations. The results demonstrate that temperature is hardly affected by the couplings. In contrast the influence of the couplings on the mechanical stresses is considerable. This is attributed to the key role that water has on bentonite swelling or shrinkage effects that are dependent on its saturation level variations. KEY WORDS: Modelling, thermo-hydro-mechanical couplings, temperature, pressure, stress. ZUSAMMENFASSUNG : Im Rahmen des internationalen Projekts DECOVALEX III wurde untersucht, wie groß der Einfluss thermisch-hydraulisch-mechanischer Kopplungen (THM) auf die Leistungsfähigkeit eines Konzeptes zur Lagerung hoch radioaktiver Abfälle zu bewerten ist. Bei dieser numerischen Behandlung wird eine generelle Lagerungskonfiguration in granitartigem Milieu simuliert. Die thermisch-hydraulisch-mechanischen Prozesse werden für eine Dauer von 100 Jahren simuliert. Bei dem Modell, mit dem das Verhalten der verschiedenen, unterschiedlich porösen Milieus in ungesättigtem Zustand dargestellt werden soll, werden die Feuchtigkeitstransporte infolge thermischer und hydraulischer Vorgänge berücksichtigt. Verglichen werden in diesem Artikel verschiedene Temperatur-, Wasserdruck- und Beanspruchungsfelder, die sich aus TM-, TH-, HM- und THM gekoppelten Berechnungen ergaben. Dabei stellte sich heraus, dass die Temperatur nur gering von den Kopplungen berührt wird. Die Einflüsse der Kopplungen auf die Mechanik sind hingegen bedeutend; ausschlaggebend dafür ist der Faktor Wasser, der den Bentonit je nach Sättigungsgrad quellen oder trocknen lässt. SCHLÜSSELWÖRTER: Modellbildung, thermisch-hydraulisch-mechanische Kopplungen, Temperatur, Druck, Beanspruchung. RESUME : Dans le cadre du projet international DECOVALEX III, une évaluation de l’importance des couplages thermo-hydro-mécaniques (THM) sur les performances d’un concept de stockage de déchets fortement radioactifs a été menée. Il s’agit d’une étude numérique simulant une configuration générique de stockage en champ proche dans un milieu granitique. L’évolution thermo-hydro-mécanique de l’ensemble est simulée sur une période de 100 ans. Le modèle utilisé pour représenter le comportement non saturé des différents milieux poreux prend en compte les transferts d’humidité sous l’effet de gradients thermiques et hydriques. L'article présente une comparaison des champs de température, de pression d’eau et de contraintes obtenues par des calculs couplés TM, TH, HM et THM. Les résultats montrent que la température est peu affectée par les couplages. En revanche, l’incidence des couplages sur la mécanique est importante; ce qui est attribué au rôle majeur joué par l’eau à travers les effets de gonflement ou de retrait de la bentonite selon la variation de son degré de saturation. MOTS-CLEFS : modélisation, couplages thermo-hydro-mécanique, température, pression, contrainte.

Jan 1, 2003

By M. D. Lionnet

The Bafokeng Rasimone Platinum Mine (BRPM) is a joint venture between Rustenburg Platinum Mines Limited and Royal Bafokeng Resources (Pty) Ltd (Bafokeng). The mining lease has been granted over Boschkoppie 104JQ and is located approximately 10 km south of the Pilanesberg Alkaline Complex. The Merensky Reef, which constitutes the principal orebody, is geologically complex. A relationship between its geological variability and the associated mineralization has been established by defining a number of facies types. The Merensky Reef has been subdivided into seven distinct facies types: the pegmatoidal facies, contact facies, FW1 potholefacies, FW3 pothole facies, FW6 pothole facies, and FW7 pothole facies. The Merensky Reef, which does not form part of the potholed reef, has a large component of footwall mineralization. The pothole facies, in contrast, has mineralization located in the hangingwall. Statistical analysis of the facies types indicates that they are unique populations and hence need to be evaluated independently. The mining lease has distinct structural domains that have added additional complications to evaluation of the Merensky Reef. The Merensky facies on BRPM exhibit unique geological and statistical characteristics within well-defined structural blocks. Due to the extreme variability of the Merensky Reef on BRPM a unique approach has been developed, within Anglo Platinum, to evaluate the deposit. Mining cuts are defined and composited for the individual facies types, and then modelled individually by applying known geological controls. The resultant grade models are weighted based on statistical and local geological knowledge. The object of weighting the facies is to replicate the variability observed in the orebody. The introduction of stringent geological controls to the evaluation process has resulted in increased confidence in the in situ grades estimated as an input to the mine planning process.

Jan 1, 2007

By A. Bhattacherjee

The Shewhart [X]?and R charts are still the most popular control charts in use today for continuous monitoring of quality data. However, for these charts to function properly, the underlying assumption of normality and independence of data must be satisfied. When either independence and/or normality of data are not present, which is a common feature of ore quality data, an application of the conventional Shewhart [X]?and R charts may introduce false alarms in the analysis of the data. To address these issues, a guideline is proposed for construction of appropriate univariate and multivariate control charts for a variety of situations. A use of this guideline to a bauxite mine suggested the construction of special cause control chart for the analysis of individual variables namely, Al2O3% and SiO2%; whereas, the multivariate T2 chart based on residuals is proposed for the bivariate analysis of the variables. The case study clearly revealed that without considering the data correlation, one may be in a state of false impression about an out of control condition while using the Shewhart [X]?and R charts for univariate and the Hotelling T2chart for multivariate analysis. To compare the effectiveness of the control charts, specifically the Shewhart [X]?and the special cause control charts, a simulation study was conducted. It was found that the conventional Shewhart chart provided lower probability of coverage than the special cause control chart. It was also revealed that the quality specification of Al2O3% is met as the variation of Al2O3% is well within the specification limits; whereas, it is difficult to meet the quality specification of SiO2% on a regular basis.

Jan 1, 2002

By W. Breytenbach

Traditionally, dithiocarbonates (xanthates) have been the preferred collectors for the flotation of platinum-bearing sulphides. However, collector development has led to trithiocarbonates (TTC), which have proven to be very effective bulk sulphide collectors. The interest in TTC flotation behaviour is currently focused on the interaction of these collectors with other collectors, specifically the dithicarbonates. Batch-flotation research has shown synergism to exist among dithiocarbonate, dithiophosphate and trithiocarbonate collectors. Increased sulphide recoveries, both for the first-minute and final concentrate, were realized using mixtures of these collectors relative to the standard.

Jan 1, 2003

By G. Taylor

A 21st Century worker is one who works less with his physical power and more with mental ability. Such a worker is more skilled than a labourer and is consequently rewarded accordingly. A21st Century supervisor is one who ensures that workers are constantly supported so that they can maximize safety and productivity. A 21st Century manager is one who constantly searches for ways to maximize returns for the various stakeholders. Given the well-known constraints in narrow reef mining, all of the above is meaningless unless a mining method is found which provides conditions which support the 21st Century initiatives. [ ] The identified mining method is a continuous non-explosive stope breaking system using rocksplitter technology. Rocksplitting is defined as: The fragmentation of rock through high energy pulse wave transmission in a fluid-filled hole or hydro fracturing. Shotholes are effectively filled with a water-based geland 30 grams of explosive after which the hole is closed off with a ?rocksplitting gun?.

Jan 1, 2000

By R. P. Jensen

This is a sampling of the papers presented at the conference, the proceedings can be bought from the SAIMM Arbitrary Lagrangian Eulerian (ALE) computational techniques allow treatment of gases, liquids and solids in the same simulation. ALE methods include the ability to treat shock waves in gases, liquids and solids and the interaction of shock waves with each other and with media from one of the other categories. ALE codes can also treat explosive detonation and the expansion of the explosive gases and their interaction with air and solids. ALEGRA is a 3-D ALE code that has been developed at Sandia National Laboratories over the past few years. ALEGRA has been applied to a 2-D simulation of presplitting using decoupled explosives in rock blasting with very interesting results. The detonation of the explosive at the bottom of the hole sends a shock wave up the borehole driven by the explosive gas expanding into air. The explosive gas compresses the air against the stemming column where it rebounds and recompresses at the bottom of the borehole. This type of ringing takes several cycles to damp out. The explosively induced expansion of the borehole is also treated by ALEGRA as well as the shock wave imparted to the rock. The presentation of this paper will include several computer animations to aid in understanding this complex phenomenon.

Jan 1, 2000

By L. K. Bandyopadhyay

The expert system component of Knowledge Base System supports the analysis and interpretation phases of ventilation design with an algorithmic program used for the solution of alternate design. The paper describes the ?ES-VENT? knowledge based system developed at Central Mining Research Institute, Dhanbad, India for an on-line diagnosing of the ventilation problems using the ?IITMRULE? expert system development tool. In the ?IITMRULE? expert system tool, it has been decided to use a backward chaining reasoning process to reach the goal state i.e. the final conclusion. ES-VENT system is made of three modules: On-line Data, Diagnostics and KBS. Each module is being a collection of several programs. The paper mainly deals with the parameters affecting the ventilation of underground mines such as air-velocity, air pressure, temperature, dust, and humidity and gas contents. The graphical presentation of these parameters on the computer and the interactive part of the developed program is expected to help a ventilation officer to determine the changes in a ventilation circuit necessary to bring the mine ventilation to the desired value. Once such changes are physically effected, the display will indicate if the changes have brought the desired effect or not on ventilation. Keywords: Ventilation network, on-line data, expert system, intelligent system, knowledge base, inference engine.

Jan 1, 2002

By J. Labuschagne

There are a number of factors that contribute to the profitability of a mine and its associated concentrator. Chief among these is the time taken from the first hoist of material from underground to the first batch of concentrate shipped. The main aim of this project was to integrate the mining model with a concentrator production schedule to minimize the time it would take to produce concentrate (without the concentrator having to stop because of a lack of feed material) in the most capital-effective manner. A secondary goal was to ensure detailed stockpiling requirements, as the concentrator is in an area where 'visual pollution' is to be avoided. To achieve these two goals a dynamic stockpile model was created by utilizing the mine production schedule and breaking it down to a daily production figure. Four different concentrator development models were then proposed. The difference between the mine production and concentrator consumption was integrated over the life of the mine to provide the accumulated stockpile tonnages for both Merensky and UG2 ore. To prevent a situation where the concentrator was operational without any feed, the stockpile levels were never allowed to fall below zero. When a development option was selected, the standard metallurgical performance calculations were used to derive a concentrate production schedule, which was used as a basis for commercial negotiations for the sale of concentrate.

Jan 1, 2013

Water represents 80?85% of the volume of mineral pulp processed in flotation circuits. Imperatives for a more detailed focus on circuit water quality and its control have come from increasing requirements to use relatively impure primary water supplies (e.g. high salinity, treated sewage) and high proportions of recycle from tailings dams, thickener overflows, dewatered and filter products. An integrated methodology for examining process water quality and its effect on minerals separation has been developed coupled with minerals surface chemistry across the complete processing circuit. Unrecognised factors, including varying proportions of water streams (daily or hourly), colloidal precipitation, highly variable pH and Eh, reaction and dissolution of minerals, minerals surface layer coatings, residual reagents and their reaction products, and microbiological activity have been studied in eight mineral processing circuits. The methodology combines: solution survey and modelling; microbiological surveys; minerals surface analysis and modelling; and process response. It has been possible to match the predicted (model) pulp chemistry with that measured from surveys of the solution and mineral surfaces. Treatment methods have included: monitored and balanced stream combinations; organic species removal; flocculation and aggregation; induced precipitation; dissolved air flotation; ageing (oxidation, UV exposure); and chemical surface conditioning of minerals. Some specific achievements from the methodology applied in plant and laboratory testing, with examples from case studies, will be described.

Jan 1, 2001

By A. Moss

The Palabora Mining Company has successfully extended the life of its operation by developing a 30 000 tpd block cave underground mine below the now closed open pit. The process of transitioning from surface to underground mining has been technically, operationally and managerially challenging. This has been due to a number of factors, in particular, the development of a block cave in a very competent rock mass. The competence of the rock mass is clearly demonstrated in the open pit that preceded the block cave, one of the steepest deep open pit excavations in the world. With cave breakthrough, however, the pit was ?instantaneously? deepened by 400 m causing a major failure of the north-west wall involving close to 100 Mt of waste material.

Jan 1, 2006

By Jeremy Bosman, Johan de Korte

Traditionally the feed to coal preparation plants was de-slimed at 0,5 mm. The +0,5 mm size fraction was processed via dense-medium cyclones and the -0,5 mm size fraction was beneficiated with froth flotation, water-only cyclones or spirals. With the introduction of large diameter cyclones, the aperture sizes of de-sliming screens have progressively increased to about 3 mm in the belief that the larger cyclones are not able to effectively beneficiate coal which has a particle size below the ?breakaway? size. The efficiency of separation in the large dense-medium cyclones is improved by presenting a coarser feed to the units. At the same time, the capacity of the de-sliming screens is increased due to the larger screen apertures and in effect, the throughput capacity of the dense-medium section is increased. The 3 x 0,5 mm size fraction, which was previously processed in the dense-medium cyclones, is now added to the fine coal size fraction and processed by water-only methods such as Teetered Bed Separators (TBS) and spirals. Whether this practice is the most economical way to process the 3 x 0,5 mm size fraction requires further thought since the best processing route for the 3 x 0,5 mm size fraction will depend on a number of factors, amongst which are: o The washability of the coal and the amount of near-density material o Processing efficiency o Specification of the required product o The price paid by the customer for the product o The cost of processing the coal Breakaway size The ?breakaway? size is defined as the particle size below which the Epm of the smaller particles starts to decrease significantly. Bosman1 provides an approximate breakaway size versus cyclone diameter (Figure 1). It should be kept in mind though that the Epm of the small particles is a function not only of the cyclone diameter but also of feed pressure, medium density, medium viscosity, particle shape and density, top-size of particles in the feed, etc.

Jan 1, 2006

To the members of The South African Institute of Mining and Metallurgy We have audited the annual financial statements of The South African Institute of Mining and Metallurgy set out on pages 451 to 460 for the year ended 30 June 2002. These financial statements are the responsibility of the Institute?s Council. Our responsibility is to express an opinion on these financial statements based on our audit. Scope We have conducted our audit in accordance with statements of South African Auditing Standards. Those standards require that we plan and perform the audit to obtain reasonable assurance that the financial statements are free of material misstatement. An audit includes: ?examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements, ?assessing the accounting principles used and significant estimates made by management, and ?evaluating the overall financial statement presentation. We believe that our audit provides a reasonable basis for our opinion. Audit opinion In our opinion, the financial statements fairly present, in all material respects, the financial position of the Institute at 30 June 2003 and the results of its operations and cash flows for the year then ended in accordance with South African Statements of Generally Accepted Accounting Practice. Auditors 29 July 2003 Council?s approval of the annual financial statements The annual financial statements for the year ended 30 June 2003 set out on page 451 to 460 were approved by the Council on 26 July 2002 and are signed on its behalf by:

Jan 1, 2003

By M. M. D. S. Vemba

Paper written on project work carried out in partial fulfilment of B.Sc. Eng (Mining Engineering) degree Engineering refers to the application of mathematics and other sciences to logically develop solutions to problems. However, in opencast mining, due to the randomness of operations, the use of mathematics is often neglected. Instead, practices that have proven successful elsewhere tend to apply. At the other end of the scale, mathematical models have been developed to identify and quantify all the operational parameters involved in the loading and haulage of ore. These are then used to optimize the operation. Optimization in this context, refers to the reduction of cost through effective utilization of the available time and resources. Considering these mathematical models, the loading and transport system at SMC (Catoca Mining Society) will be assessed with a view to its optimization. The discussion will be introduced by considering the mine background and other general information, which will highlight the main operational variables.

Jan 1, 2004

By A. Varadarajan, M. Hashemi, K. G. Sharma

Quartz mica schist collected from Nathpa-Jhakri Hydropower Project, Himachal Pradesh, North India is tested under triaxial loading using a servo-controlled loading system. Complete stress-strain-volume change behaviour including post peak softening behaviour of the samples, are presented. Strength and deformation parameters are given. Quarz mica schist, der von Nathpa Jhakri Hydropower Projekt, Himachal Pradesh gesammelt wird, wird Nördlich Indien unter triaxial geprüft, der von Gebrauch eines servo kontrollierten Ladesystems beladung. Vollständiges Spannung-Spannung-Band Änderung Verhalten Postens Spitze Erweichung Verhaltens der Proben, wird überreicht. Kraft und Verformung Parameter werden gegeben. Mica à quartz schist recueilli du Projet de Hydropower de Nathpa Jhakri, Himachal Pradesh, l'Inde du nord est essayé sous l'utilisation de chargement de triaxial un système chargeant servo réglé. La tension complète-la tension-comportement de changement de volume y compris la poste sommet amollir le comportement des échantillons, sont présenté. Les paramètres de force et déformation sont donnés.

Jan 1, 2003

After the closure of collieries, they naturally start to fill up with water. As a result, hydraulic gradients develop between them and different hydraulic pressures are exerted onto peripheral areas or compartments within mines. This results in water flow between mines, or onto the surface. This flow is referred to as intermine flow. The collieries in the Witbank Coalfield have geometries such that there are several areas where this intermine flow is possible. Since the Department of Water Affairs and Forestry has declared intermine flow as one of its greatest concerns for granting closure to South African mines, much research into this phenomenon is required. The challenges in determining intermine flow are numerous, and attention has focused on identification of areas where these flows can take place. The quantification of these flows is problematic due to the uncertainties in exact geometric configurations and the variation in site-specific hydraulic properties of thecoal and overlying lithilogical layers. During this study, use has been made of numerical flow modelling and several analytic solutions to test the applicability of the flow models as well as to predict groundwater flow directions, filling times of voids and flow volumes. The numerical modelling methodology entailed a downscaling approach starting with a broad regional model covering the entire area, followed by modelling the interactions between interconnected mines, and finally looking in detail at the major areas of interaction.

Jan 1, 2005

[Dr. N.A. Barcza (Chairman) Mr. R.J. Linnell (Vice Chairman) Mr. J. Basson Dr. L.A. Cramer Mr. W.A. Gericke Dr. N.C. Machingawuta Mr. C.S. Mahony Dr. L.R. Nelson Mr. D. St J. Slater Mr. B.J. van der Walt INFACON X TECHNICAL PROGRAMME COMMITTEE Dr. L.R. Nelson (Chairman) Mr. W.A. Gericke (Vice Chairman) Mr. W. Barrett Mr. T.R. Curr Dr. O.F.R.A. Damm Prof. R.H. Eric Mr A.M. Hearn Mr. A.R. Jamieson Dr. N.C. Machingawuta Mrs. L. Mthombeni Mr. F.X. Prins Mr. J. van Tonder ]

Jan 1, 2004