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By D. D. Howat, J. van der Colf

This paper is the first in a series of three dealing with this subject and also with the rate of oxygen removal from the slags in the presence of solid carbon and with the physicochemical properties of the reduced slags. For selected members of the system, the melting temperatures and primary crystallization products were determined. as were the viscosity and the electrical resistivity of the corresponding melts. All the experiments were conducted in a neutral atmosphere. Where determined, the primary phase was found to be either perovskite or magnesium aluminium titanate. The composition variable exerting the most pronounced influence on viscosity or resistivity was found to be the basicity expressed as the mass ratio (CaO + MgO)jSiO,. The ratio CaOjMgO became important only at Iow basi<:ity values. Although generally there is a direct proportionality between log (viscosity) and log (resistivity), slags h&apos;lving either a very high silica content or a very high titania content have anomalously Iow electrical resistance.

Jan 1, 1979

By S. Fazluddin, K. C. Sole, M. R. Serwale, T. Coetsee

The CSIR-Ti process employs lithiothermic reduction of titanium tetrachloride feedstock to produce titanium sponge. The product is therefore contaminated by a range of lithium and chloride species. In this study we examine the effects of particle size, temperature, and HCl concentration as input leaching variables on the removal of chlorides from the crude titanium sponge. A review of the aqueous chloride chemistry of Li and Ti provided initial conditions for leaching of impurity species from the sponge. Experimental results confirm that the effectiveness of leaching and removal of dissolved impurities from the sponge are dependent on leaching kinetics, which are influenced by temperature, particle size, and morphology. Of the variables tested, reaction temperature had the strongest influence on the oxygen content of the leached product. The HCl lixiviant concentration had a negligible effect under the conditions tested. Leaching of crude titanium sponge (−10 mm size fraction after crushing) at 14°C in either 1 M or 0.032 M HCl yielded a titanium sponge product that met the ASTM standard specification for commercially pure Grade 1 titanium, i.e., oxygen content < 0.18 mass% and chloride content < 0.15 mass%.

Dec 13, 2022

Metso Minerals Cisa have developed VisiofrothTM - a system which calculates parameters of the froth surface using vision from remote cameras mounted about individual flotation cells. The parameters calculated from this system can be utilised within process control strategies to achieve stabilisation or optimisation of the flotation process. As part of a JKMRC AMIRA P9 field campaign, froth vision was collected from various cells operated at different air rates and froth depths within Rio Tinto&apos;s Northparkes copper roughing and scavenging circuit. At the same time, samples were collected to determine the cell metallurgical performance at each operating condition. These froth images have been processed using the VisiofrothTM system with froth velocity, bubble size, froth collapse rate and various froth colour parameters calculated. These parameters have been compared to the measured concentrate flow and concentrate grade produced at each condition. This analysis shows that the concentrate tonnage flow is strongly correlated with froth velocity whereas the concentrate grade is best correlated using froth velocity in combination with a bubble stability parameter which affects the bubble size distribution on the top surface of the froth. This paper summarises the results from this analysis as well as an overview of the VisiofrothTM system and the parameters that are measured by the software.

Jan 1, 2007

The Institute was founded in 1894 as the Chemical and Metallurgical Society of South Africa. In 1904 it was reconstituted as the Chemical Metallurgical and Mining Society of South Africa and in 1956 it became the South African Institute of Mining and Metallurgy. The objects of the Institute are to advance the science and practice of mining and metallurgy, to afford opportunities for the interchange and recording of knowledge of mining and metallurgy and to ensure high standards of professional conduct and competence. Membership benefits include monthly issues of the Journal of the Institute, General Meetings at which papers are read, symposia, excursions to mining and industrial concerns and the use of club facilities at Kelvin House. Technical journals received on an exchange basis are available to members at the Johannesburg Public Library. The current membership of the Institute is over 1 600. Membership applications are accepted from suitably qualified persons and the requirements for entrance to the various grades of membership are summarised below. Fellows shall not be less than 30 years of age, shall be university graduates in pure or applied science or shall produce evidence to the satisfaction of the Council that they have successfully completed a co-ordinated course of study in pure or applied science of at least three years&apos; duration at an approved university or institution deemed by the Council to be of equivalent status. Members shall have been employed in senior technical positions in important mining or metallurgical undertakings for at least five years or they shall have practised as mining or metallurgical consultants for at least five years. They shall be practising their profession at the time of application. Entrance fee R10,00, Annual subscription R20,00. Letters of designation: F.S.A.I.M.M. Members shall be not less than 25 years of age and shall be university graduates in pure or applied science, or shall have successfully completed co-ordinated courses of study in pure or applied science of at least three years&apos; duration. They shall have been engaged in work of an approved technical character in the mining or metallurgical industries, of which not less than two years shall have been in positions of responsibility. A candidate shall be practising his profession at the time of his application. Entrance fee R8,00, Annual subscription R18,00. Letters of designation: M.S.A.I.M.M. Associates shall be not less than twenty-five years of age, and shall have been engaged in positions of responsibility in, or associated with, the mining or metallurgical industries for periods of not less than three years. If, however, the candidate for admission to the higher grade of Associate, is at the time of his application, already a Student, he need satisfy the Council only that he is, at the time of his application, engaged in a position of responsibility in or associated with the mining or metallurgical industries. In all cases the applicants shall satisfy the Council that they are fit and proper persons to become Associates. Entrance fee R8,00, Annual subscription R18,00. Graduates shall be not less than 21 years of age and shall be university graduates in pure or applied science, or have completed co-ordinated courses of study in pure or applied science of at least three years&apos; duration at an approved university or institution. They shall not remain Graduate members after attaining the age of 30 years without the permission of Council. Entrance fee R2,00, Annual subscription R12,00. Students shall be persons not less than 18 years of age who are being educated or trained in a manner approved by the Councils to occupy a technical position in or associated with the mining or metallurgical industries and who, furthermore, shall not have attained the qualification required for a higher grade of membership. They may remain Students until they have obtained the necessary qualifications for transfer to a higher grade of membership, but not after the end of the Institute&apos;s financial year in which they attain the age of 28 (twenty-eight) years. They shall then transfer to a higher grade to retain membership of the Institute. The Council may relax the provisions of this clause in such cases as it considers appropriate. Entrance fee nil; Annual subscription R5,00. Other. The Council has the power to elect to the grade of Fellow or Member, candidates who may not fulfil all the requirements for entrance to these grades but whose status, professional achievements and practical experience in mining or metallurgy justify such election. Applications. Requests for membership application form should be addressed on the attached form to the Secretaries South African Institute of Mining and Metallurgy, P.O. Box 61019, Marshalltown, Transvaal.

By M. Timucin

High-temperature phase relations and thermodynamics of the condensed phase region of the Pb-S-O system at 1473 K were analysed by use of the available information. The sub-regular solution models on Pb-PbS and PbO-PbSO4 continuous melts were used in conjunction to generate a consistent set of thermodynamic and phase equilibrium conditions for the Pb-S-O system. The directions and distributions of conjugation lines between melts of this system were derived with relevant activity and composition data. The calculations permitted the thermodynamic analysis of direct lead smelting and the construction of isothermal reaction diagrams for the system in terms of oxygen and sulphur partial pressures at 1473 K.

Jan 1, 1989

By G. P. Schoonraad, J. E. Clay

Treatment of zinc silicates by the Waelz Process by J. E. CLAY (M.I.M.M.) (Visitor) and G. P. SCHOONRAAD. Pr. Eng.. B.Sc. Eng. (Rand) (Member) A review is given of the Waelz process. The chemistry of the process and the mechanism of crust formation (accretions) are briefly dealt with. The plant of Kiln Products Limited and its operation are described. The problems encountered and methods for their elimination are presented.

Jan 8, 1976

By J. W. Latilla, J. J. van Wijk

In late 1997 a request was received to assist with determining the powered support unit (shield) load capacities for the planned 2 seam short wall. This project had a number of aspects which made it attractive to utilize numerical modelling in conjunction with other more conventional design tools in the design of the shields. Amongst these were: The 2 seam panels were to be laid out about 25 m below the previously short walled 4 seam, the 4 seam had in turn been over-mined by the 5 seam long wall, the proposed face height of the 2 seam short wall was 5.5 m while the 4 seam had been mined at 4 m. The top seam in the area (5 seam) had been mined at between 1.5 and 2.2 m high, the face conditions with about 95 m of broken material applying dead weight loading to the 2 to 4 seam inter-burden septum were hard to predict and cyclical loading due to the presence of strong sandstone bands in the 2 to 4 seam inter-burden. The basic thrust of the study was to take the known, and successful, situation (4 seam short wall) and carry out comparative modelling to enable prediction of likely 2 seam conditions. Some two dimensional aspects studied were: 5 m goaf hanging up behind shields, stresses in beams to determine likely first goaf roof span, stresses in cantilever beams to asses cyclical loading due to sandstone bands in the interburden being loaded by the overlying goaf and stresses on chain and crush pillars adjacent to the goaf edge. Three dimensional aspects that were investigated included: Load distribution along face for close goafing and 5 m goaf hang-up and load in a 1 m wide rib modelled in the position of the powered support units. From the modelling it was possible to determine the optimal shield leg capacity of the new 2 seam equipment. These outputs were used when drawing up the technical specifications for manufacture of the new equipment. The face was successfully commissioned in August 2002. Fin 1997, requête fut faite pour aider à la détermination des capacités de charge pour l’unité de soutènement mécanisée (bouclier) pour la couche 2 courte taille en projet. Certains aspects de ce projet le rendaient intéressant pour utiliser la modélisation numérique en même temps que d’autres méthodes conventionnelles pour la conception des boucliers. Parmi ces aspects se trouvaient : Les panneaux de la couche 2 devaient être placés environ 25 m au dessous de la couche 4 courte taille ; la couche 4 avait été remplacée par la couche 5 longue taille ; la hauteur de taille proposée pour la couche 2 courte taille était 5.5 m, tandis que la couche 4 avait été exploitée à 4 m. La couche supérieure de la région (couche 5) avait été exploitée entre 1.5 et 2.2 m de hauteur ; il était difficile de prédire les conditions de taille, avec environ 95m de matériaux cassés ajoutant une charge morte à la plaque de séparation entre les couches 2 et 4 et un chargement cyclique causé par des bandes de grès dans l’entre-fardeau 2-4. L’idée principale de l’étude fut de prendre la situation connue et réussie (couche 4 courte taille) et de faire une modélisation comparative pour prédire les conditions probables de la couche 2. Certains des aspects à double dimension qui furent étudiés étaient : Un accrochage de remblai de 5m derrière les boucliers ; contraintes dans les poutres pour déterminer le premier intervalle probable entre remblai et toit ; contraintes dans les poutres en porte-à-faux pour évaluer le chargement cyclique causé par les bandes de grès dans l’entre-fardeau qui est accablé par le remblai et les contraintes sur les piliers par chaîne et d’écrasement adjacents au bord du remblai. Aspects à trois dimensions qui furent étudiés : Distribution de la charge le long de la taille pour les remblais proches et l’accrochage de remblai de 5 m et la charge dans une nervure de 1 m de large modelée dans la position des unités de soutènement mécanisées. La modélisation a permis de déterminer la capacité de portée optimale du bouclier du dispositif nouveau pour la couche 2. Ces résultats furent utilisés pour dresser les spécifications techniques pour la fabrication de l’équipement nouveau. La taille fut commissionnée avec succès en août

Jan 1, 2003

By E. Garab, M. Pillalamarry, E. Develo

"Recent geological exploration at Rosh Pinah mine revealed that the mine’s major production is shifting towards the western orefield, which will increase the demand for air flow to be supplied to this area. A snapshot of the ventilation survey carried out in December 2014 at the western orefield drill drive B (WOF-DDRB) showed that the air flow was well below the required standards. In order to improve the existing conditions, possible options were considered and simulated using Ventsim™ software.The best option found was to replace the existing western orefield fans with the larger fans from the inactive southern orefield workings, to increase the air flow in the DDRB district. Simulation showed that as much as 20 m3/s of air can be received at the working faces of WOF 30, compared to the previously received amount of 1.37 m3/s. The economic analysis indicated that the above option can reduce the ventilation cost by N$1.9 million annually. It was also noticed that after implementing this option together with other projects, the ventilation conditions in the mine were greatly improved and currently give no cause for concern. IntroductionA good mine ventilation system should be capable of providing adequate quantity and quality of air to all working faces, and is critical to the occupational health, safety, and comfort of underground employees (Luxbacher and Ramani, 1977; Exikis and Kapageridis, 2006). No ventilation system can remain adequate indefinitely; as the mine workings are extended, the ventilation characteristics such as system pressures, air volumes, leakages, and airway resistances change considerably. Continuous improvement of the ventilation system is needed to ensure compliance with health and safety regulations (Lovejoy, 2010). It also ensures that the right quality and quantity of air is delivered to all the necessary areas at the lowest possible cost. This can be achieved by identifying inefficient airways and poorly ventilated areas in the mine and planning how best to upgrade them.The latest geological exploration shows that the focus of production at Rosh Pinah mine is shifting towards the western orefield (WOF). As mining progressed, the working areas have advanced away from the main fans, which increased the resistance to air flow drastically and resulted in increasing demands being imposed on the main fan in order to supply an adequate air flow. This process also created more leakage paths between the fan and the working areas, which has caused the air to short-circuit before it can reach the faces. Consequently, a much larger quantity of air has to be circulated by the fan so that the stipulated quantity reaches the face, which increases operating costs (Singh et al., 2004)."

Jan 1, 2016

[The following notations will be used: O an ore body. W a sample of size w located in O; the size of this sample. W a block or a sample, of size W, located in O; the size of this block or sample. z&apos; a point in W. W&apos; a block or a sample, of size W&apos; greater than or equal to W, located in O; the size of this block or sample. z" a point in W&apos;. y (h) point semivariogram in O. s (h) point covariogram in O. In the previous chapter, we saw that the point semivariogram y (h) usually cannot be estimated directly from the data available. Rather, the values of samples of size w are available in O, and from these a regularized semivariogram y w (h) can be estimated. The following relationship has been proved (5.8): Y w(h) = Y (w;w+h) - Y (w;w). y (w;w+h) is the average value of y (z&apos; z") when z&apos; takes all possible positions in a sample w and z" all possible positions in a sample w+h of the same size, h being the distance between w and w+h. y (w;w) is the value of y (w;w+h) for h = 0, i.e. the average value of y (z&apos; z") when z&apos; and z" take all possible positions in w. We also saw that the regularized covariogram aw(h) is related to the point covariogram a (h) as follows (5.9): w(h) Gr In the following chapters, it will be shown that calculation of the average value y of y, or -a of a, in the general case relating to samples or blocks W and W&apos; which need not be of the same size, plays a very important part in all the practical applications of geostatistical theory. The purpose of this chapter is to introduce various methods of calculating y and a-. Furthermore, mathematical equations and graphs are provided which can be used when the point semivariogram can be represented by one of the more common equations, and when the blocks W and W&apos; are of simple shape. By definition (Fig. 6.1): [ ] Y (W;W) = WW f dz&apos; f y (z&apos; z") dz" (6.1) in W z" in W&apos;]

Jan 1, 1978

By D. G. Krige

The problem of a realistic investment analysis for a new mining venture that sells its products on the international metal markets IS studied against the background factors, firstly, of different inflation rates between the countries hosting the mines and those. hosting the metal markets; and, secondly, of the changing pattern of currency exchange rates between such countries. The purchasing-power parity theory is used to establish a pattern of relationship between these two factors, and to develop a more logical approach to the long-term forecasting of metal prices in the currency of the country in which the mine is situated.

Jan 1, 1979

By I. Ince, S. Kahraman, M. Rostami, B. Dibavar

The density, porosity, and strength of rocks are fundamental in the design of geo-engineering projects. Determining these properties requires the preparation of smooth core samples, which is usually impossible for soft rocks. Besides, only fragmented samples may be available in some projects. A method for predicting rock properties from rock particles such as drilling debris would therefore be useful. This study was undertaken to develop prediction equations for compressive strength (UCS), tensile strength (BTS), density, and porosity values from the crushability index (CI) obtained from rock fragments. The results showed that UCS, BTS, density, and porosity were strongly correlated with the CI. The physical characteristics and strength of rocks may be predicted with the help of the derived equations. The CI test is a valuable tool for estimating rock properties in drilling projects and in situations where core specimens are not available.

Mar 14, 2024

By J. O. Claassen

"SynopsisMining value chains are dynamic systems and should be managed according to systemic flow-based principles. This includes a detailed focus on the impact of variable geological conditions on material flow, product quality, and production cost, visibility of the total mining system to operators and managers, as well as the synchronization of resources and activities in downstream processes. Thirty mining operations across the African continent were studied to establish to what extent systemic flowbased principles are applied in day-to-day operations. The study indicated that although most mining operations have identified the relevant geoprocessing variables, only a small number apply this information in a flow-based management approach. Most mining operators do not focus on developing a clear flow view of the mining value chain and on making it visible to operators and managers to enable them to optimally set and reset operations. Daily synchronization of geoprocessing variables is limited to a small number of variables, e.g. synchronizing ore hardness with drilling or milling requirements, in less than 30% of the operations evaluated. Operations where these principles have been adopted reported a noteworthy improvement in performance. The study indicates that notable potential exists in most of the operations evaluated to implement flowbased management principles, including geometallurgical principles. This can significantly improve value chain performance without exorbitant capital layouts and enhance ROCE. IntroductionObjective of the studyThe study seeks to establish to what extent systemic flow-based principles have been adopted in the southern African mining industry and the implications thereof. Specific attention is given to the importance of defining and managing geoprocessing dependencies (geological variables directly impacting mining and plant performance – the geometallurgical approach), establishing a flow view of the mining system, which typically includes a dashboard of the flow of ore/product quality and cost from the mining face to the customer, and limiting the impact of dependencies through synchronization of activities and resources, e.g. ensuring that a continuous miner does not wait for a roofbolter, or that reagent addition rates are matched with a specific ore/concentrate composition."

Jan 1, 2015

By S. M. Graham, G. Mellis

"The determination of the oxidation state(s) of an element present in a solid sample may be required for a number of reasons, including the assessment of the degree of reduction which has taken place during a multi-step production of a metal. In addition, possible flaws in a metal may result from small amounts of oxides included in the solid. The analyte of interest may be present as a major component of a sample of interest, or as a minor impurity - beneficial or requiring removal - in another matrix.Numerous methods have been established for the analysis of species in solution samples - for example, Fe2+ and Fe3+ by titration, Cr6+ by colourimetric means, etc. With appropriate knowledge of the solution being analysed, many of these methods are fairly straightforward, extremely reproducible and accurate. In those instances where the analyte in a solution is known to be in only one form, the analysis is even more straightforward, since it can be achieved instrumentally (by AAS, rCP-OES or rCP-MS, for example).However, the situation with respect to the analysis of solids is not as simple. Various techniques - such as X-ray diffraction - are routinely used by our mineralogists to obtain information about the various minerals present in solid samples, and thus about the oxidation states of the analyte elements present. However, these techniques usually give results that are qualitative, or semi-quantitative at best. They are also usually time-consuming and expensive. One of our colleagues at Mintek, Deshenthree Chetty, has done extensive work in developing a method for the quantification of manganese species in solids using mineralogical methods, and this is no small achievement."

Jan 1, 2014

By Peter Smith

The construction of one of the world&apos;s largest goldrecovery plants to treat run-of-mine ore is progressing on schedule at the President Brand Gold Mine in the Orange Free State. Designed to treat 390 kt per month, the plant will recover 96 per cent of the gold from the ore at a capital cost of 160 million rands in terms of January 1983 money. It will replace the existing gold-treatment installation, as well as provide a 30 per cent increase in capacity. Mintek reports Report M161 Improved recoveries of gold from auriferous calcines and pyrites by fine milling. Report M171 The development of a versatile computer programme for the evaluation of batchflotation results. Report M178 The reduction of chromite in a transferred-arc plasma furnace. Report M179 Optimization of an inductively coupled plasma by the simplex method.

Jan 1, 1985

By T. Nyakudarika

The Unki Platinum Mines concentrator, employing an MF2 circuit configuration which includes fully-autogenous primary milling of run-of-mine (ROM) ore, was commissioned in November 2010. The project was Anglo American Platinum?s first PGM concentrator in Zimbabwe and would form a significant contribution to the group?s platinum production. The project financials demonstrated that the project was operating-cost sensitive. After reviewing the metallurgical testwork, mineralogical examinations, and the history of similar operations, it became apparent that the Unki ore characteristics rendered it amenable to autogenous milling. The primary ball mill, structurally designed for 30 per cent steel load, could be operated at the required initial phase throughput with fully-autogenous primary milling, realizing savings in both power requirements and grinding media consumption. The original mill sizing had been done with fully-autogenous milling in mind, but allowing for flexibility and mitigation in case of varied mining fragmentation. Since attaining steady state, target grinds have been achieved. This paper looks at the Unki ore characterization programme, design considerations, and the operational and control philosophy for a successful comminution circuit, and discusses the design to produce a flexible, low opex, mitigated comminution and overall MF2 flowsheet that is easily expanded in line with the potential for optimum exploitation of the orebody.

Jan 1, 2012

By J. P. Beukes

South Africa holds approximately three-quarters of the world?s viable chromite ore resources and dominates the global production of ferrochrome. Albeit completely unintended, small amounts of Cr(VI) are formed during ferrochrome production. Certain Cr(VI)species are regarded as carcinogenic, hence making the treatment of some ferrochrome waste materials necessary. In this paper, the Cr(VI) treatment strategies currently employed by the South African ferrochrome producers are investigated by means of a literature review and a questionnaire survey. From the discussion, it is evident that various treatment strategies are available to deal with Cr(VI)-containing waste in the ferrochrome industry. However, by far the most commonly applied treatment strategy remains the aqueous reduction of Cr(VI) with ferrous iron. The advantages and the correct application of this strategy, together with the disadvantages and pitfalls, are argued. Innovative improvements on historic practices are also discussed

Jan 1, 2012

By M. B. Cortie

An account is given of the development of ferritic stainless steels since their discovery in the early years of this century. The alloys became very widely used in the 1950s, the market during that decade being driven strongly by a demand for automobile trim made of ferritic stainless steel. The production of ferritic stainless steel declined as a proportion of the total at the end of the 1950s as consumer preferences changed. However, the market is now growing strongly again, this time driven by a demand for oxidation-resistant alloys for motor-vehicle exhaust systems. The tonnages produced, applications, and market shares of the various alloys are discussed and compared. Trends in world stainless-steel production, product forms, technological development, and usage are examined.

Jan 1, 1993

By W. Newcomen, G. Dick

"Effective management and mitigation of pit slope instability in open pit mines begins with a comprehensive slope monitoring programme. The ability to differentiate between non-critical pit wall movements due to rebound or relaxation of the excavated slopes and movements that may be indicative of slope failure is important for maintaining a safe working environment and maximizing production. Slope failure prediction methods using velocity, acceleration, and strain criteria have been introduced and put into practice over the past few decades. Forty-eight slope failures with surface monitoring data are presented and assessed using the strain-based failure prediction approach, with consideration of the quality of the rock mass and the potential failure mechanism. The results indicate that the strain-based approach can be used to provide general guidance regarding strain thresholds for pit walls for a variety of failure modes in diverse geological environments. The advantages and potential drawbacks of the strain-based and other slope failure prediction methods are discussed. The importance of implementing a pit slope monitoring and performance evaluation system early in mine development is also emphasized. IntroductionThe successful prediction of the Manefay Slide pit slope failure at Bingham Canyon at 9:30 am on 10 April 2013 (Engineering and Mining Journal, 2014) highlighted the importance of having a comprehensive slope monitoring system that provides an accurate prediction of the time of failure of an open pit slope. Using most of the geotechnical monitoring tools available, the time of the failure was predicted within hours and equipment and personnel were evacuated from the pit well in advance of the failure. From a time to slope failure perspective, the monitoring system in place was a success.There are two general groups interested in monitoring pit walls, with slightly different objectives in mind when the monitoring system is being set up. There are those at the mine site that have to implement the pit slope design, monitoring protocols, and the action response plans, and there are those designing the slopes (often consultants) who regularly visit the mine but may not be responsible for the day-to-day activities. was a success.There are two general groups interested in monitoring pit walls, with slightly different objectives in mind when the monitoring system is being set up. There are those at the mine site that have to implement the pit slope design, monitoring protocols, and the action response plans, and there are those designing the slopes (often consultants) who regularly visit the mine but may not be responsible for the day-to-day activities."

Jan 1, 2016

By D. Moses, J. A. Onyango

Carbonatites are generally competent rock masses with rock mass rating class II rating 60–74. In spite of their competency, they tend to be affected by weak features like manganese-iron veins and/or in situ rock damage due to brecciation associated with carbonatite complexes. Rock slope failure in such hard rocks is complex since such structures within the rock mass form weak links that could potentially control slope instability. In this contribution, a numerical simulation using phase2 v 7.0 was carried out to investigate the influence of in situ rock damage on the stability of mine pit walls. The outcome reveals that, the existence of breccia in the competent rock mass has the capability to reduce the slope stability performance particularly at gentle dipping angles of emplacement in close range to the slope toe. However, as the emplacement position of breccia moves away from the pit wall, the stability performance increases at gentle dipping angle <50º. On the contrary, at the dipping angle of 50° the performance of slope reduced, and at steeper angles >50° the impact becomes negligible. Thus, from a series of analyses, mine design in brecciated rock masses, the ratio of 1:5 between the breccia distance from slope toe and pit depth should be implemented to counter its impact, and if the breccia is within or close to the pit limit, a deliberate effort must be made to mine it out.

Sep 1, 2025

"Chairman: Prof A. E. H. BLEKSLEY Rapporteur: Prof J. ELBRONDPanel Members: Prof J. C. Griffiths, Prof T. E. Hawkins, Mr A. C. Langton, Mr M. Splaine, Mr A. WeissThe reasons for failure of computer applications in the mineral industry and the direction of future developments.The Chairman opened the discussion by elaborating on the disappointment felt by some authorities with the lack of progress in the application of computers in the mineral industry during the last ten years, and posed the question to the panel : &apos;Do you agree that the computer age has not come up to expectations?&apos;Mr Langton said that although there seemed to be a tremendous amount of brainpower applied to the theoretical side, he thought that the production men had not got all the help from computers that could have been given to them. The computer, said Prof Griffiths, is as yet a new tool which should not be used to do old things in old ways. To learn to use the computer will take time. After all, he said, it had taken 400 years after the introduction of the printing press to achieve general literacy, and perhaps it will take 40 years after the introduction of the computer to achieve `numeracy&apos;.In Mr Weiss&apos; view, the reason for the feeling of disappoint¬ment lay in the focussing of attention on the computer. The blame, if any, lay with the people surrounding the computer, that is, the analysts and programmers, to whom the emphasis should be shifted.Prof Hawkins said that he thought that some applications of the computer in the mineral industry had been successful, such as, for example, the compilation of payrolls. Reasons for failures in other areas were to be sought in the fact that the people connected with computers had failed to realise that they were merely part of a system. They had not understood the power structure of the organization which their work tended to change, and were therefore not prepared for the inevitable conflict with the production men.In Mr Splaine&apos;s view the production man had not received the assistance he could have had from the computer people because he may possibly not have allowed this to happen.Prof Bleksley concluded from these opinions that the promise which computers had ton years ago had not been fulfilled and added that the opinions expressed by the panel had intruded on his next question which was: &apos;Is the reason for this that people are involved?Prof Hawkins elaborated on his previous theme, namely, that of computer people in relation to management. Com-puter people, he said, were trying to impose change on management but were not prepared to share the responsibility for these changes. In fact, they wanted their work to be distinct and separate, and, as far as management was concerned, changes would be made when management believed that these would be less agonizing than no change at all."

Jan 1, 2014