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By H. W. J. P. Neomagus, R. K. K. Mbaya, J. R. Bunt, N. T. Leokaoke, N. W. Makgobelele

Silicon Smelters consumes more than 80000 t/a of wood-derived charcoal as carbonaceous reductant in the production of silicon metal. More than 10% of this material is discarded as fines (<6 mm) generated due to abrasion during processing. Charcoal fine residues (<650 μm) and polyvinyl alcohol (PVA) binder were used in this study to produce mechanically strong charcoal briquettes for metallurgical application as carbonaceous reductant. The PVA binder was added in mass percentages of 1, 3, and 5 wt% to the charcoal fines. The compressive strength, abrasion resistance index (ARI), drop shatter resistance (SRI), and water resistance index (WRI) were measured as functions of curing for up to 7 days under atmospheric conditions, and the results compared with metallurgical grade coarse charcoal. The ash content of the produced briquettes was found to be high (6.6–8.0%) compared with the coarse charcoal (1–3%). The 3 and 5 wt% PVA-bound briquettes were found to be the strongest, with compressive strengths of 40 and 115 kg/cm2 respectively, with WRI values of 75 and 73% respectively. The produced briquettes were found to have lower ARI and SRI values compared to the coarse charcoal. Future work should include beneficiation of the fine charcoal discards prior to briquetting, and an increase in binder addition to above 6 wt% to improve the ARI and SRIn.

May 1, 2021

A well known rock mass classification system has been altered slightly to address the issues found under remnant mining conditions. By detail study of the expected fracture patterns and local geology, the rock mass is classified to indicate the condition of the hanging wall prior to mining. The risk level of each mining step is evaluated by calculating input parameters for computer simulations from the actual rock mass condition. Seismic activity is catered for by the understanding that large event rates and large magnitude events reduce the quality of the local rock mass and that the rock mass stiffness should be adapted accordingly. A case study is presented to test parts of the protocol. Un système connu de classification des masses rocheuses a été légèrement modifié pour faire face aux questions posées par les conditions d’extraction de débris. Une étude détaillée des diagrammes de fragmentation et de la géologie locale permet de classer la masse rocheuse pour indiquer la condition du toit avant l’extraction. Le niveau de risque de chaque étape minière est évalué en calculant les paramètres d’entrée pour simulation par ordinateur à partir de la condition réelle de la masse rocheuse. L’activité sismique est prise en compte avec la réalisation que les taux de larges évènements et les évènements de large magnitude réduisent la qualité de la masse rocheuse locale et que la raideur de la masse rocheuse doit donc être adaptée. Une étude de cas est présentée pour tester des sections du protocole. Ein sehr bekanntes Gesteinsmassenklassifikationssystem wurde abgeändert um die Probleme zu behandeln die unter Restabbaukonditionen angetroffen werden. Durch detaillierstes Studium der der zu erwartenden Bruchmuster und der lokalen geologischen Verhältnisse wird die Gesteinsmasse in Hinblick auf die Konditionen der Flözoberseite klassifiziert. Das Risikoniveau für jeden Abbauschritt wird durch die Eingabeparameter aktuellen Gesteinsmassenkondition für die Computersimulation evaluiert. Für die Seismische Aktivitäten wird Sorge getragen durch das Verständnis, daß große Ereignisraten und Ereignisse hoher Größenklassen die Qualität der lokalen Gesteinsmasse reduzieren und daß die Gesteinsmassensteifheit entsprechend adaptiert werden sollte. Eine Fallstudie um Teile des Protokolls zu testen wird präsentiert.

Jan 1, 2003

By G. L. Smith

As the Platinum mining industry expands in the Eastern Limb of the Bushveld Complex it is increasingly evident that a major constraint to development is a lack of appropriate infrastructure. Of critical concern are water resources and spatial development / infrastructure. This paper identifies the context for infrastructure development in the Eastern Limb and two solutions that have evolved in the areas of water supply and spatial development. INTRODUCTION In an economics context, infrastructure is considered to be the structural elements of an economy which allow for the production of goods and services, without themselves being part of the production process. Despite the lack of a specific definition, infrastructure has largely become understood as to comprise road and rail transport systems, public transport systems, airports, public educational facilities, water supply and water resources, wastewater management, solid waste treatment and disposal, electric power generation and transmission, telecommunications and hazardous waste management systems. Critically it is important to understand that infrastructure not only comprises these physical elements but also the operating procedures, management practices and developmental policies that facilitate the effective utilization and development of the infrastructure in response to societal demand.

Jan 1, 2008

By J. L. van Niekerk, J. Gunaselvam

This study investigates the use of appropriate seating systems for the control of whole-body vibration exposure in vehicles used in the SA mining industry. Six suspension seats were tested with six test subjects to determine the most suitable seat for an articulated dump truck based on the EM1 requirement in ISO 7096 (2000) standards. Transmissibility functions were measured in the laboratory using the newly commissioned Dynamic Seat Testing Facility with two excitation levels of 1m/s2 and 2 m/s2 r.m.s. in the 0.5 - 30 Hz frequency range. SEAT values were calculated for two input spectrums, the EM1 input spectrum specified as in ISO 7096:2000 and measured road vibration data measured on a typical articulated dump truck. The averaged SEAT value calculations indicated that not one of the seats will qualify as an ISO 7096 (2000) suspension seat but that it is possible to select a seat that will significantly reduce the vibration the driver will be exposed to.

Jan 1, 2003

By A. Bouvard, N. Hoteit, E. Boidy, F. Pellet

In the context of the construction of an Underground Research Laboratory devoted to the feasibility studies of radioactive waste deposits, it appears of the utmost importance to study the long-term behaviour of rock, over a long time period. In this paper, some results of tests performed on the argillite from the Meuse-Haute-Marne site test in Eastern France are presented. Then a numerical simulation of one of this test using the viscoplastic damaging constitutive law proposed by Lemaitre is presented. Finally, this law is used to simulate numerically the behaviour of the rock at the wall of a circular tunnel in order to determine the extension and the change along the time of the Excavated Damaged Zone (EDZ). Advantages and limitations of the model are discussed. Dans le cadre de la réalisation d’un laboratoire de recherche souterrain conçu pour étudier la faisabilité d’installations de stockage de déchets radioactifs, il apparaît fondamental de caractériser non seulement le comportement viscoplastique à très long terme des matériaux mais aussi les phénomènes d’endommagement consécutif à la redistribution de contraintes provoquées par l’excavation des cavités. On présente ici les résultats d’essais réalisés sur les argilites du site de Meuse/Haute-Marne et destinés à caractériser leur comportement visco-endommageable. Il est ensuite procédé à une application de la loi viscoplastique endommageable de Lemaitre pour simuler l&apos;un de ces tests. Les apports et les limites d&apos;un tel modèle sont mis en évidence par des simulations numériques du comportement de la roche au pourtour d&apos;une galerie circulaire permettant de suivre l’évolution au cours du temps de la zone endommagée (EDZ) à la paroi . Im Rahmen des Baus eines unterirdischen Forschungslabors für die Untersuchung der Machbarkeit von Deponien für radioaktive Abfälle erweist es sich als äußerst wichtig, das langfristige Verhalten von Gestein über einen langen Zeitraum zu untersuchen. Im vorliegenden Artikel werden einige Ergebnisse von Untersuchungen vorgestellt, die mit Tonschiefer aus der Meuse-Haute-Marne in Frankreich durchgeführt wurden. Anschließend wird eine numerische Simulation der Untersuchungen unter Verwendung des von Lemaitre vorgeschlagenen viskoplastischen Verformungsgesetzes vorgestellt. Schließlich wird dieses Gesetz auf die numerische Simulation eines Kreistunnels angewandt, um die Ausdehnung und die zeitliche Entwicklung der Auflockerungszone (EDZ) zu bestimmen. Es werden die Vorteile und Grenzen des Modells diskutiert.

Jan 1, 2003

By R. Zivojinovic, S. Vujic

The structural age of the capital mining machinery, representing a part of the system of the Electric Power Industry of Serbia, has been dictated by the initiation and development of open pit coal mines. For example, the oldest bucket wheel excavators were installed some thirty-four years ago, and the average life of the relevant machinery exceeds twenty-two years. Operation of both capital equipment and machinery has direct effects on economic and business activities of open pit mines, and consequently forced us to make a decision and study thoroughly the problem of establishing the optimum exploitation life of capital mining equipment at the open pit coal mines of the Electric Power Industry of Serbia. The aim of this paper is to define and discuss the relative problems as well as to find out the possible solutions and establish the methodology for estimating the optimum exploitation life of machinery. The study was successfully carried out by a team of scientists engaged from and coordinated by the Department of Computer Science of the Faculty of Mining and Geology, University of Belgrade. This paper presents the key observations covering the subject problem. Keywords: Mining, Opencast exploitation, Coal, Optimization, Exploitation life, Capital machinery, Electric power industry, Dynamic programming.

Jan 1, 2003

By E. Wolmarans

Dowding, Reynard and Associates Mineral Projects (DRAMP) was approached by the ARM/Lion Ore JV during July 2006 to conduct a feasibility study and control budget estimate for a new greenfield project for their NKOMATI Nickel mine 45 km east of Machadadorp. The scope included the evaluation and review of previous studies as well as a techno-economic trade-off on four possible comminution circuits ranging from conventional crushing and ball milling to fully autogenous milling. The following document encapsulates the thought process, decisions and the references used in selecting the final comminution route for the new 375 ktpm MMZ concentrator. Apart from the pilot test work performed, design simulations from a number of sources, performance results from a recently commissioned 100 ktpm MMZ concentrator, together with an understanding of the geology and mineralogy of the orebody and possible variations in the characteristics of the orebody over the life of mine were assessed. The results from all the above-mentioned work indicated that it would be possible to treat the MMZ ore at the desired throughputs to the desired grind sizes in a fully autogenous grinding (ABC-type) circuit. Autogenous milling is generally considered to be one of the higher risk milling circuits. This is mainly due to the fact that the ore, which is utilized as the grinding media, could be variable in terms of hardness and mineralogy/geology. Nevertheless, it is a very popular route as the cost benefits, more specifically the operating cost, are normally very attractive. This is especially the case when large low grade orebodies are evaluated. In North/South America, autogenous and semi-autogenous grinding circuits have been successfully employed during the past 20 years on large scale low grade operations. Taking all the above factors into account, the DRA/Nkomati project team recommended an autogenous circuit with the option to add steel to both the primary and secondary mills (if required) for the new operation in order to create the opportunity for significant operating cost savings. One has to bear in mind that all the new design simulations and decisions are based on previous work and potential unknown variations within the orebody will never be fully understood until the pit is operational for some time.

Jan 1, 2009

Mineral sand beneficiation plants comprise a complex combination of electrostatic, magnetic and gravity based separation techniques. These are combined and replicated in ways that provide the most efficient and cost effective separation of the valuable components. On line instrumentation has been developed at the JKMRC (eg. conductor/non-conductor(CNC) ) to measure the properties of the dry plant process streams. This paper provides results from the recent development of a novel low cost mass flow meter and discusses their combined use with the CNC instrumentation for the control of dry separation circuits.

Jan 1, 2003

By F. Bonnet, J. Lehmann, H. Gaye

A review of thermodynamic information and models of slags, including associated software when available, is presented. The pertinence and accuracy of these models is discussed by comparison of their predictions for various slag thermodynamic properties with the available experimental data. Practical industrial applications will be illustrated by a literature review of the dephosphorization process of ferromanganese alloys and by the description of Ti behavior during silico-manganese alloys production. This latter example will show how the thermodynamic models have been used to propose a flotation treatment at low temperature to enhance TiC removal.

Jan 1, 2004

By Kurt R. P Petersen

This paper discusses the current approaches to modelling the DMS cyclone within the De Beers group. Current efforts are split into short term value-adding process understanding and longer term semi-fundamental analysis of separation mechanisms. To date, the basic applied approach has yielded significant value to the group, enabling operators to focus on simple diagnostic measures to control their process. The more involved modelling approach has given rise to a new understanding of the separation field, in particular that the high density gradients within a cyclone are highly localised, indicating that separation of medium to heavy density material takes place low in the cone. The model has proven to be conceptually robust, but still requires further development and validation to become a complete modelling and simulation tool for De Beers.

Jan 1, 2006

By S. Erçayhan, B. Derin, O. Yücel

In the present study, the production of low carbon ferrochromium (LC-FeCr) from chromite concentrates containing 55.09% Cr2O3 and 13.06% Fe via metallothermic process was investigated. For this aim, in the experiments, the aluminothermic reduction method was applied in an open crucible. 10% CrO3 + 10% NaClO3, 15% CrO3 + 5% NaClO3 and 20% CrO3 by weight of concentrate were added to the charge, respectively and the charge was reduced with aluminium. The experiments were done with the additions of 90, 100, 110, 120 and 130% of stoichiometric requirement of aluminium. The highest Cr content in alloys was found as 71.7% at 120% of stoichiometric Al whereas the highest Cr recovery in alloys was found as 71.8% at 130% of stoichiometric Al when the both charge contained 15% CrO3 + 5% NaClO3 by weight of chromite concentrate.

Jan 1, 2004

By P. He

Abstract This paper introduces the test results of dark-gray calcium-shale, discusses the infection of strength characteristic and deformation characteristic due to the angle between structural planes. Keywords calcium-shale, failure form, strength, deformation characteristic, structural planes. Zusammenfassung: basier auf der Anwendung von Problematik des Felsenbauprojektes und Beschaffenheit Felsen unter Beaugnshme auf den Zustand des Druckes von einzeler Welle legt dieser Text dar, wie der Winkel der Schichtstrukturflaeche des schwarzgrau kalziumhaltigen Schieferblocks auf die Zerstoerungs-, Intensitaets- und Deformationseigenschaften einwirkt. Schluesselwoerter: schwarzgrau kalziumhaltigen Schiefer, Zerstoerungseigenschften, Intensitaetseigenschften, Deformationseigenschaften, Flaeche dar Schichtstruktur. Résumé – En fonction de la configuration du massif rocheux sous l’état de la contrainte de pression axiale simple et de la pratique de l’ingénierie de roches, le présent article fait la déscription concernant l’influence de l’inclinaison ? de la couche de structure stratifiée du bloc de schiste calcaire gris noir sur ses caractéristiques de destruction, sa spécificité de résistance ainsi que sa nature de déformation. Mot clés – Schiste calcaire gris noir, Caractéristiques de destruction, Spécificité de résistance, Nature de déformation, Couche de structure stratifiée

Jan 1, 2003

Mr G H Park was born and brought up in Zimbabwe, in mining from the University of the Witwatersrand. Starting as a Learner Official at Rand Mines, he went Mr D J van Niekerk was educated at Helpmekaar Boys&apos; High School in Johannesburg and the University of Pretoria. Mr C J C Janse van Vuuren was educated at Klerksdorp High School, Pretoria Technical Colege, the University of Pretoria, and Unisa. He holds the folowing degrees: BSc (I&S), BSc Hons (Met Pta), ND (Met Tech), AEP (Unisa). Prof. R F Sandenbergh was educated at the Afrikaanse Hoerskool Germiston and the University of Pretoria. He holds the degrees of B Ing (Chem), M Ing (Chem), and D Ing (Metal). President&apos;s Award Professor Jannie van Deventer, Head of the Department of Metalurgical Engineering at the University of Stelenbosch, has been honoured with one of the five President&apos;s Awards for 1990. These awards are made by the CSIR&apos;s Foundation for Research Development. G R Bozzoli Awards* Prof. Alan Kemp, Dean of the Faculty of Engineering at the University of the Witwatersrand, has appealed to industry not to cut bursary funding during recessionary times.

Jan 1, 1990

By R. Strydom, J. H. Selby

Published information is available on the radiological impacts of disposing of zircon sand in a landfill. Zircon flour by virtue of its finer particle size presents a different set of issues during disposal. This paper describes two options for disposal of such fine grained materials – namely incorporation into concrete aggregates and agglomeration by addition of cement. The study considers the radiological exposure of the public from such disposal methods and concludes that these options are viable alternatives for the safe disposal of waste zircon flour. The disposal of zircon into concrete aggregates at a rate of 10 per cent produces a sufficiently low effect to allow such aggregates to be used in building foundations or other such mass concrete applications. The use of cement agglomeration methods will also provide a safe method of landfill disposal provided at least 20 cm of soil cover is included.

Jan 1, 2003

By M. L. Baharani

Looking for an idyllic paradise that has investment and business potential as spectacular as the stunning views of mountains, the rich Ganesh Himal zinc-lead deposit exposed between 4,050 m and 5,000 m is the answer. Arising from the sea floor in a span of 55 million years, the enchanting Himalayas had remained one of the most potent factors influencing the Asian region. The challenges of the mighty Himalayas notwithstanding, it continues to provide opportunities for the humankind in optimum usage of the natural resources and sustainable development. Optimal management of natural resources in mountain areas through decision support tools offered by remote sensing will go a long way in realization of the Ganesh Himal Zinc-Lead Project. The authors have a real life endeavor spanning over 37 years in developing a mining industry in a mountainous region of Nepal and an attempt to integrate with the development of other natural attributes of the region. With rapid acceleration of science and technology, humankind has acquired power to transform his environment countless ways and on an unprecedented scale. While mineral resources are the pillars on which we have built industry and infrastructure, industrial countries in the North have been in the forefront of technological advancements, the developed countries of the South have been at the receiving end of exploitation of mineral resources worldwide. A relationship with natural environment, re-crafted by the civilizing impulse, to meet human demands are upcoming challenges for management of natural resource in sustainable manner for a livable world.

Jan 1, 2008

By I. R. Firth, D. L. Taylor

Metal mining operations, in particular gold mining operations, use intensive ore control procedures in order to manage the extraction of ore zones from benches containing both ore and waste material. Typical grade control procedures rely on blast hole samples to indicate ore grade. Statistical techniques and geological controls are then used to create two-dimensional polygons, which indicate zones of material designated as ore. These ore-polygons are calculated using pre-blast material locations and are generally not corrected for rock movement caused by blasting. This lack of correction appears to exacerbate the material mischaracterization problem of sending ore to the waste dump and/or waste to the mill. One Nevada gold mining company has estimated that this could be a $10 million per year problem for their operations. Using a simplified vector field algorithm, a method of taking point movement data and interpolating post-blast positions for all nodes in a polygon has been developed. Currently working in 2-dimentions (X-Y), this algorithm utilizes the movement vectors calculated from pre-and post-blast positions of targets placed in a blast, to generate a spatial transformation function for any point on the bench. This transformation is then applied to the nodes of the ore-polygons to produce modified dig lines ore polygons reflecting distortion and movement resulting from the blast. The method as implemented uses common mine planning routines and is performed using the Surpac software suite. The method may be adapted to use any pre-and post-blast point movement data available, and most mine planning suites include the simple interpolation algorithms used. Keywords: Blast movement; Ore control; Open pit blasting; Grade control

Jan 1, 2003

By T. Khumalo, L. Musenwa, S. Masemola, M. Kgaphola

"In 2017, Petra Diamonds completed the construction and commissioning of a modern, fit-for-purpose diamond processing plant at Cullinan Diamond Mine (CDM). The design of CDM’s milling circuit is unconventional in that it comprises an autogenous (AG) mill with a grate discharge with large ports, low-revolution jaw crushers, and high-pressure grinding roll crushers with large operating gaps. In this paper we review the design to provide guidance on what is expected from the milling circuit and to demonstrate how the design aims to address challenges experienced in the old plant, which was based on staged crushing technology. We assessed the performance of the CDM AG milling circuit from commissioning and early production stages to examine its impact along multiple dimensions. In the assessment we sought to understand the lessons from our milling circuit regarding diamond liberation, energy consumption, and the future of diamond processing as a whole. IntroductionCullinan Diamond Mine (CDM), previously known as Premier Mine, is an underground diamond mine owned by Petra Diamonds. Petra Diamonds is a leading independent diamond mining group and a growing supplier of rough diamonds to the international market. Petra Diamonds is listed on the Main Market of the London Stock Exchange under the ticker ‘PDL’. Petra’s total resource of 305 million carats ranks third by size after De Beers and ALROSA (Petra Diamonds, 2018).CDM was established in 1902. The mine rose to prominence in 1905, when the 3106 carat Cullinan Diamond — the largest rough diamond of gem quality ever found — was discovered there. The mine has produced over 750 stones that are larger than 100 carats and more than a quarter of all the world's diamonds that are larger than 400 carats. Cullinan is renowned as a source of large, high-quality gem diamonds, including Type II stones, as well as being the world’s most important source of very rare blue diamonds (Petra Diamonds, 2018)."

Feb 1, 2019

By Jeffrey C. Hillman

The need to recruit locally produced engineers by the South African Mining Industry led to the Engineering Faculty at the University of the Witwatersrand developing a number of academic bridging initiatives for educationally disadvantaged students. The graduation rate achieved during the initial five years of operation by the most successful of these programmes has been on a par with that of al other students but the performance of subsequent intakes has declined to such an extent that the continuance of this scheme could now be at risk. One reason for this reduction in throughput is that many of the applicants for the increasing number of mining bursaries have been more interested in the bursary than the profession and have either failed or dropped out due to a lack of application and motivation. This will have serious consequences for both Wits and the Industry if it continues and some method of identifying unsuitable or suspect applicants needs to be introduced as a mater of urgency. It is recommended that an introductory course be set up at a working mine that would be run under the auspices of Wits, as a joint venture with industry, and include a level of academic input that would provide both bridging needs and certain first year credits. The final form of this course will require extensive consultation with al parties but needs to be completed before the end of 1996. It is further recommended that the advertising and promotion of mining careers be expanded and much improved.

Jan 1, 1996

By A. C. Moorgas, J. Divall

This study investigates the feasibility of using waste iron slag, the by-product from a mineral sands processing works, in road construction. The study includes the different options investigated for the treatment of a leachate that is produced during the cooling of the iron slag, prior to processing. It also reviews the reasons for choosing the current treatment option that is being trialed. Cooling the iron slag with water results in the formation of a leachate with a high pH and high sulphide concentration. This leachate can seep into the ground and, over time, it will contaminate the ground water. A system was designed to collect and treat the leachate to prevent contamination of surrounding natural water sources. Numerous leachate treatment options were investigated to find cost effective method of treatment After cooling, the iron slag is passed through an iron recovery plant and the unsaleable product is placed on a dumpsite. Rain percolates through the dumpsite, which can result in the formation of a leachate that can contribute to a contaminated plume. After extensive testwork, it was found that the dumpsite, which was leached of contaminants, could be screened and used as a G5material (specifications in Table II) in road construction. The initial challenge was to establish that this material was environmentally safe for use in this particular application. Approval from the Department of Water Affairs (DWAF) was required for the testwork and then for the long-term use of this material in the construction industry. The following challenge involved establishing a market for the material. Construction companies in the area were reluctant to change to a new product that was not naturally occurring. The economics of this project are extremely sensitive to transport costs and hence only projects within a specified radius can be supplied with the Black Top Gravel (BTG). This project is not are venue generator, but it does save the money that would be required to manage the dump, and it reduces the closure costs.

Jan 1, 2003

By M. Tangstad, H. Brun, P. Calvert, A. G. Lindseth

In 1999, Eramet bought the ferromanganese plants in Porsgrunn and Sauda (Norway) and Marietta (USA). With an ownership in the Comilog mine, the plants will operate with a high amount of Comilog ore. The properties of Comilog ore are reviewed and compared to a number of industrial operations. Important ore properties are chemical and mineralogical analyses, CO reactivity and mechanical strength. The advantage of Comilog ore is its contribution to lower energy and coke consumption. However, special precautions must be taken regarding the amount of fines and water introduced in the furnace, as Comilog ore is more porous compared to other Mn ores.

Jan 1, 2004