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Book Reviews M. J. Jones(ed.). Geological, mining and metallurgical sampling London, The Institution of Mining and Metallurgy, 1974. 268 pp. £8. Spooner, J., et al. (eds.). 1974 miningannual review, London, The Mining Journal Limited, June 1974. 506 pp. £14,25 (including annual subscription to Mining Journal and Mining Magazine). J. H. Quilliam et al. (eds.). The ventilation of South African ~old mines. Johannesburg, Mine Ventilation Society of South Africa, 1974. 488 pp. RI0,00. The Hans Merensky Foundation As announced in a recent brochure, the 25-year-old Hans Merensky Trust has been converted to The Hans Merensky Foundation, its main objective being 'to promote and assist in the development of the resources of the Republic of South Africa and neighbouring territories articularly such natural resources as soil, water, minerals, flora and fauna-and to promote the health and welfare of the inhabitants; more specifically by research, experiment and demonstration and through the correlation and application of scientific knowledge'. Applications for S.A.I.M.M. membership and transfer Please note that new application and transfer forms have been issued.

Jan 11, 1974

By A. A. Bradley, P. J. D. Lloyd, A. J. Freemantle

Developments in centrifugal milling by A. A. BRADLEY,B.Sc. (Rhodes) (Visitor), A. J. FREEMANTLE, B.Sc. Hons. (Wits) (Visitor), and P. J. D. LLOYD, B.Sc. (Chem. Eng.), Ph.D. (Cape) (Fellow) The theoretical and experimental results of a study of centrifugalmills are reviewed. Means for the scaling up of such mills are suggested, and tests on a prototype mill are described. Despite the high lining wear in the centrifugal machine, which reduces its productive availability, its other advantages suggest that there is merit in pursuing its further development.

Jan 6, 1974

By G. P. Dyke

The MRMR Classification System was developed specifically for mining applications, namely caving operations, and is one of three rock mass classification systems used in the South African mining industry today. Increased usage of the MRMR Classification System has raised concerns that it does not adequately address the role played by discontinuities, veins and cemented joints in a jointed rock mass. To address these concerns, Laubscher and Jakubec introduced the In-Situ Rock Mass Classification System (IRMR) in the year 2000. Although the IRMR System is more applicable to a jointed rock mass than the MRMR System, a quantitative comparison of the MRMR and IRMR Classification Systems indicates that there is not a significant difference between the resultant rock mass rating values derived from the two Classification Systems.

Jan 1, 2008

By P. De Kock

Strategic mine planning is concerned with the decisions that determine the value of the business, while tactical planning deals with the tasks to realize that value. When tasked with formulating a strategic mine plan, the mining engineer often turns to commercially available software. However, these software packages have limited applicability to the RBM situation. Adopting a simpler, back to basics approach founded on a deep understanding of the economics of the orebody has the advantage of providing a clear logic to guide tactical planning. By creating a coherency between strategic mine planning, and tactical planning the likelihood of successfully executing the plans and attaining the value promised by the strategic plan is increased. This paper describes the reasons why RBM embarked on a strategic mine planning process, the rationale of choosing the process, and the process itself.

Jan 1, 2007

By D. Seke

Metal inventories are usually reported in financial statements of mining companies. However, the value of these inventories can be reliable only if the metals in stock are measured within acceptable tolerances. Reliable metal balancing requires accurate mass measurement, sampling, and chemical analysis. Many mining companies are usually unable to validate the accuracy of metals in inventories at the end of their financial year. This is mainly due to poor mass measurement, sampling, and chemical analysis practices. This has an adverse impact on metallurgical accounting and metal valuation. In addition, it puts a lot of stress on external auditors, who have the duty to recommend the approval of the financial statements to the board of directors. Although a full value chain of metal reconciliation includes the accuracy of Mineral Reserve definition and grade control at the mine, this paper discusses the implementation of best practices for mass measurement, sampling, and chemical analysis at processing plants. This is an important aspect of sampling and reconciliation that is required in order to improve the reporting of inventories in the financial statements of public mining companies. Keywords metallurgical accounting, corporate governance, sampling, analysis.

Jan 1, 2014

By N. T. Beukes

An engineering house?s perspective of required inputs in designing a copper electrowinning tank house and ancillary equipment calls for both understanding of the key fundamental controlling mechanisms and the practical requirements to optimize cost, schedule and product quality. For direct or post solvent extraction copper electrowinning design, key theoretical considerations include current density and efficiency, electrolyte ion concentrations, cell voltages and electrode over potentials, physical cell dimensions, cell flow rates and electrode face velocities, and electrolyte temperature. Practical considerations for optimal project goals are location of plant, layout of tank house and ancillary equipment, elevations, type of cell furniture, required cathode quality, number and type of cells, material of construction of cells, structure and interconnecting equipment, production cycles, anode and cathode material of construction and dimensions, cathode stripping philosophy, plating aids, acid mist management, piping layouts, standard electrical equipment sizes, electrolyte filtration, impurity concentrations, bus bar and rectifier/transformer design, electrical isolation protection, crane management, sampling and quality control management, staffing skills and client expectations. All of the above are required to produce an engineered product that can be designed easily, constructed quickly and operated with flexibility.

Jan 1, 2009

By J. K. Pothal, S. Basu, R. Barik, P. K. Senapati, A. Dubey

The aim of this paper is to study the characteristics of limestone particles (size varies from 4 mm to 20 mm) during its transportation from open cast mines through pipes. The influence of four different size fractions of limestone samples (4–6 mm, 6–10 mm, 10–15 mm, and 15–20 mm) on pipe flow characteristics during vertical transport in a 100 mm NB hose pipe was investigated. The flow velocities in the vertically lifting pipe was varied from 0.95 m/s to 2.78 m/s and a rotary feeder of 2 to 4 tonne/hr. capacity was employed to feed the limestone samples to the lifting pipe. The pressure drop data for the different size fractions of limestone samples at different mixture velocities were analysed. The effect of input volume fraction and superficial velocity of limestone samples on hold-up ratio were discussed. It was indicated that there was no substantial increase in pressure drop of slurry samples in the studied range of concentrations (CW = 4.22% - 12.54%), particle size, and low to medium range mixture velocities with respect to water run head loss data. The hold-up for the larger size fractions (15–20 mm) of limestone samples was found to be significant as compared to smaller size fractions, which may be due to terminal settling velocities of individual fractions of the studied samples.

Mar 4, 2025

The following is available free of charge from the Bismuth Institute, rue Brederode 9, B-I000 Brussels, Belgium: The chemical analysis of bismuth. Automatic methods of guiding welding heads along butt joints. Investigations into lamellar tearing. A technical survey of seam tracking methods in welding. Review - Seawater corrosion handbook, by M. Schumacher (editor). New Jersey, Noyes Data Corporation, 1979. New journal February 1979 marked the appearance of a new monthly journal, Lloyd's Shipping Economist. New edition Gasification of coal, a basic study of existing processes and new developments, by H. D. Schilling, B. Bonn, and U. Krauss (edited by W. Peters). Essen (West Germany), Verlag Gltickauf GMBH, 1979. 2nd revised edition. 336 pp. 68DM (approximately R32). In German. South African technikons The six autonomous colleges for advanced technical education in South Africa were established in terms of the Advanced Technical Education Act (Act 40 of 1967). However, since the inception of these colleges, it has become clear that members of the public find the name difficult to use and to remember. Consequently, these colleges, which play such an important role in the community, were not always correctly identified. Die forging The 9th International Conference on Die Forging will be held from Monday, 4th to Saturday 9th May, 1981, in Diisseldorf, Federal Republic of Germany. It is being organized jointly by the Forging Committee of the Verein Deutscher Eisenhiittenleute and the Vereinigung Deutscher Freiformschmieden. High-temperature alloys An International Conference on the Behaviour of High Temperature Alloys in Aggressive Environments will be held in Petten (North-Holland) from 15th to 18th October, 1979. Strategic minerals The National symposium on the availability of strategic minerals, which is being organized by the Institution of Mining and Metallurgy in collaboration with the Fellowship of Engineering, will be held at the London Press Centre, New Street Square, London EC4, on 20th and 21st November, 1979. The symposium has as its main objective consideration of those minerals that may pose problems of availability in the United Kingdom. Underwater mining The 10th Annual Underwater Mining Institute is scheduled for 1st to 3rd October, 1979, at Galveston, Texas. The Institute will be cosponsored by the Sea Grant College Programs of the University of Wisconsin and Texas A & M University and by the Marine Science Institute of the University of Texas it is being held in co-operation with the Association for Marine Mining. Die Suid-Afrikaanse Instituut Vir Mynbou En Metallurgie - Inligting Oor Lidmaatskap.

Jan 1, 1979

By J. Levin

The Bond standard grindability test provides a Work Index that is widely used to estimate the energy required for grinding, but the test cannot be applied to fine materials such as plant tailings and middlings. For such materials, a comparative grinding test must be used in which a reference material from an operating plant is ground in a laboratory mill to determine the 'equivalent' energy consumption per revolution of the laboratory mill. As the Bond grindability test mill and its operating conditions are specified, its equivalent energy consumption per revolution should be a constant, here designated as B. Once B has been determined, the mill can be used to estimate the grindability of fine materials without the need for reference materials. A value of B can be calculated from any Bond grindability test, and 245 tests that were conducted at Mintek were examined to determine its value. A wide range of values was found, but most of them were grouped around 198 x 10- 7 kWh/rev, which is taken as the best estimate of B that is available at present. Values of B that are not close to this figure are obtained from materials for which the Bond grindability test gives misleading or 'spurious' Work Indexes. These spurious Work Indexes lead to the apparent departure of B from its true value. Some limitations of the Bond grindability test arise from its use of a mill without litters and of screening, instead of classification, to close the circuit.

Jan 1, 1989

By C. Musingwini, A. S. Nhleko, P. M. Muke

Open-pit mine planning includes the determination of a long-term open-pit mine production scheduling (OMPS) plan. The OMPS plan is generally a three-dimensional (3D) block extraction sequence that seeks to maximise the net present value (NPV) of future cash flows, while complying with technical and operational constraints. The OMPS problem is computationally complex because it involves the analysis of large datasets, while simultaneously incorporating both multiple hard and soft constraints. The OMPS problem has been solved using deterministic or exact approaches, heuristic, and metaheuristic models. When compared to heuristic and metaheuristic models, deterministic approaches tend to take much longer to solve the OMPS problem when the number of constraints increases. Therefore, this paper presents a metaheuristic model which utilises a genetic algorithm (GA) framework to solve the OMPS problem. The GA-based model was applied to the Newman1 and Zuck Small mining instances, which are publicly available from the online MineLib database. The NPVs for the OMPS plan generated using the GA-based model for the two case studies were compared to the best-known published MineLib solutions obtained using the TopoSort heuristic model at the time of this study. For the Newman1 instance the equivalent annual NPVs were approximately US$6.6 million for the GA-based solution and US$5.1 million for the TopoSort solution. For the Zuck Small mining instance, the equivalent annual NPVs were approximately US$99.8 million for the GA-based solution and US$102.5 mil for the TopoSort solution. These results show that the GA-based model produced comparable solutions to some of the best-known solutions, thus, indicating strong potential application of GA-based models to solve OMPS problems.

Sep 1, 2021

By A. J. Dickson, A. M. Starfield

This paper reviews the progress made to date in the development of computer models of heat and moisture transfer from rock surfaces to the ventilating air in deep-level mines. The application of these programs to ventilation planning and design is discussed.

Jan 1, 2014

By L. Lorig

"Two types of extreme event, earthquakes and rainfall, potentially affect open pit slope stability. In the case of earthquakes, there are rather well-developed analysis procedures and acceptability criteria. The analysis procedures relate mainly to selection of the dynamic loading either through design earthquakes and/or pseudo-static seismic coefficients. The acceptance criteria are typically expressed in terms of a minimum safety factor in pseudo-static analyses. The acceptance criteria are often promulgated by governments despite the fact that no open pit slope has ever been adversely affected by an earthquake. This paper explains why open pit slopes are seemingly more resistant to dynamic loads than natural landforms, which can experience catastrophic landslides.Extreme rainfall events are much more likely to cause open pit slope problems than earthquakes. Two types of problem are common – slope erosion and slope instability. Slope erosion is often mitigated by appropriate surface water controls. Slope instability due to elevated transient water pressures is more difficult to mitigate. Analysis procedures and acceptability criteria are rare. This paper will discuss the mechanisms for rainfall-induced slope instability, as well as analysis methods. Examples will be discussed and analysis methods are proposed. IntroductionTwo types of extreme event, earthquakes and rainfall, potentially affect open pit slope stability. In the case of earthquakes, there are rather well-developed analysis procedures and acceptability criteria. The analysis procedures relate mainly to selection of the dynamic loading either through design earthquakes and/or pseudo-static seismic coefficients. The acceptance criteria are typically expressed in terms of a minimum safety factor in pseudostatic analyses. The acceptance criteria are often promulgated by governments (e.g., Peru, Chile) despite the fact that no open pit slope has ever been adversely affected by an earthquake. This paper explains why open pit slopes are seemingly more resistant to dynamic loads than natural landforms, which can experience catastrophic landslides.Extreme rainfall events are much more likely to cause open pit slope problems when compared to earthquakes. Two types of problems are common – slope erosion and slope instability. Slope erosion is often mitigated by appropriate surface water controls. Slope instability due to elevated transient water pressures is more difficult to mitigate. Analysis procedures and acceptability criteria are rare, but do exist. In Peru, for example, slopes are required by law to be designed for a 100-year storm."

Jan 1, 2016

By N. J. Roodt

Mine dumps created in terms of the pre-MPRDA regime (old order mine dumps) are currently not regulated by the MPRDA, and the common law owners of such dumps are free to process them without the need to obtain the relevant rights. The MPRDA Amendment Act purports to change this position. However, the wording of the Amendment Act raises a number of problems which render the post-amendment position at best unclear and at worst absurd and unworkable. The primary concern with the Amendment Act is that, on one interpretation, material placed on the same dump at different times may be treated differently at law. Thus, parts of a dump may be subject to one person?s right while others may be subject to another?s right. Moreover, case law has generally regarded mine dumps as movable property and, by extending the MPRDA to apply to all mine dumps, the Legislature is extending the ambit of the Act to cover movable property, a scenario not contemplated by the wording of the Act (even after its amendment) in relation to applications for rights. The better interpretation of the amendments, which are not yet in force, is that they will not apply retrospectively to old order mine dumps.

Jan 1, 2010

By W. A. Hodgson

"In order to be able to map the variation in the concentration of elements in soils, it is necessary to sample at intervals that will give adequate coverage of the area and will allow determination of the rate of fluctuation of concentration with distance in any environment. This rate of fluctuation with distance can be referred to as the continuity of concentration.The continuity of concentration in soils varies according to the chemical characteristics of the element being considered, the underlying rock type or orebody and in response to the dispersion processes that operated during soil formation. Within any environment there is a maximum distance between sampling points within which adjacent sample values are related. This distance, the critical sampling interval, can be determined by means of a correlograrm.Where the sampling grid has been chosen to provide an adequate coverage over unmineralized rock, adjacent samples being related, anomalies may be missed if the element continuity in the anomaly is less than in the background. Results show that a knowledge of the critical sampling interval of the environment being examined may used to select a more efficient sampling pattern for a geochemical survey."

Jan 1, 2014

Mining executives often have a difficult task determining what the strategic objective of the business should be as this can be impacted by the prevailing market conditions. In addition, they have no mechanism to quantitatively 'test' the impact of this strategic decision on the business and understand the underlying dynamics. During the commodities bull run of 2003 to 2008 the strategic objective may have been to grow the long term value of the business (NPV) through increased tonnage, acquisition and finding new reserves, which all came with an increasing fixed cost base. Now with the financial crisis upon us and the collapse of commodity prices and demand, executives have adjusted their strategies as 'cash is king' and short-term cash flow, in some instances at the expense of long terms value, is the order of the day. For many mining companies, mine closures, reductions in production and cost cutting exercisers are now the focus. In many instances, management do not have an ability to rapidly test different strategic alternatives to 'test' the impact on value, unit costs, reserves and profitability at the operational level and optimize the underlying trade-off variables. Economic modelling of the complete business value chain is a means of linking the operational 'reality' and strategic choices, so that the full impact can be assessed. This paper describes some of the challenges facing mining executives and how economic modelling can be applied to make decision making more rigorous.

Jan 1, 2010

By W. J. Jordaan

The ability of soils to retain and hold cations is called the cation exchange capacity (CEC). Adsorbed cations, however, can be replaced by other cations through the process of cation exchange. Heavy mineral deposits contain a significant portion of slimes including the very fine clay minerals. In most circuits the slimes fraction hampers efficiency and has to be removed during early stages of the process. Being a nonvaluable process stream, the processing of the slimes is a costly exercise. In thickening applications it might be possible to manipulate the ability of clay minerals to retain and hold positively charged cations in order to optimize flocculation and therefore reduce flocculation costs. The CEC value of the slimes could be a measure of this possibility. To investigate this hypothesis, different slimes samples were characterized for size, chemical composition and clay minerals present. The CEC value of each sample was determined and explained in terms of the mineral phases present. Settling tests were conducted and an attempt was made to explain the CEC characteristics of the clay minerals in terms of settling rate. The scope of this investigation was to test the hypothesis and should not be seen as an in-depth study of the subject matter. A greater number of samples and detailed analyses to identify and quantify minerals and phases present would be required to investigate further the relationships between clay minerals in the deposit, CEC and settling rates. Location and geological setting Exxaro KZN Sands is mining a heavy minerals deposit at Hillendale mine located at Richards Bay, South Africa. The orebody consist of a dune some 8 km inland from the coast to the north of eSikhawini. A geological synopsis undertaken by Botha1 concluded that the Hillendale mining area represents a coastal dune sequence that accumulated north of the Tugela River. The northward movement of sediment by long shore drift currents result in a high sand budget on the beaches north of the river youth and is the dominant contributing factor to the accretion of the coastline and development of parallel dune systems along the coastal zone in this area. Beach swash zone processes and enrichment of the fine sand fraction occurs during wind transport off the beach by ascending parabolic dunes that form the coastal barrier dunes. This process results in heavy mineral concentration on the windward dune face and localized enrichment parallel to the dune forms. The aeolian sedimentary facies processes result in the primary concentration of higher grades in the upper silt-enriched reddish brown horizons of the profile. The synopsis by Botha1 further showed that an additional component of heavy mineral concentration can be ascribed to the post-depositional relative enrichment of heavy minerals due to weathering. Therefore, it is likely that the Hillendale orebody protolith was pedogenically weathered to form the homogeneous, silt-enriched, clayey reddish brown to dark red, palaeosol profile that grades downwards into yellowish brown, less clay-enriched sand. Slimes characterization Samples The Hillendale orebody was divided into geochemically discretized zones based on the concentration of ilmenite and other specific minerals and/or phases. Six composite samples were made up from exploration samples taken from Zone 9, Zone 11 and Zone 12. The red and orange horizons within these composite samples were separated and test samples were prepared to conduct test work and analyses. The test samples were submitted for preparation and analysis to characterize the slimes properties. Each test sample was deslimed at 45 µm representing the slimes fraction (-45 µm) and dried at 40°C. The -45 µm slimes samples were then split to conduct size analysis, chemical analysis, XRD and to determine the CEC. Size analysis The size distribution of the composite samples is shown in Table I. The size analysis shows that there is a difference in size distribution between the orange and red horizons of each zone. The orange horizons contain less 850 µ material as well as less slimes (-45 µm). The red horizons contain yore slimes (-45 µm). The size distribution of the slimes fraction (-45 µm) was determined using Malvern size analysis. The cumulative particle size distribution of the slimes is shown in Figure 1. The red horizons of the different zones show similar size distributions. The orange horizons show some differences. However, there is a difference in size distributions between the red and orange horizons.

Jan 1, 2007

By J. Petersen, H. Naderi, M. H. Nikzad, M. Karimi

In this research, the thermodynamic study of sodium persulfate (Na2S2O8) solution in the presence and absence of H2SO4 and Fe3(SO4)3 was done. Eh-pH and equilibrium distribution diagrams were constructed using Outotec HSC Chemistry Software and the main stable ionic species were determined. Also, the mean activity coefficient and Pitzer model coefficients were evaluated. Effects of system composition, sodium persulfate concentration and temperature were investigated. According to the results, HS2O7 -, HS2O8 -, S5O3 2-, S4O3 2-, S3O3 2-, HS- and NaSO4 - are the main stable species in these three systems. Increasing of sodium persulfate concentration resulted in disappearing of SO4 2- and the appearance of NaSO4 -. The main effect of increasing the temperature from 25 to 75oC, is changing the stability regions of HS2O7 -, NaSO4 -, SO4 2- and S2-. From equilibrium studies, it was concluded that at 25 and 50oC, increasing the persulfate concentration results in a 55-60% decrease for HS2O7 - and an 20- 30% increase for HS2O8 -. At 75oC, HS2O8 - becomes the main species and its percentage decreases with increasing the persulfate concentration. Keywords: Thermodynamic, sodium persulfate, activity coefficient

Jan 1, 2020

By N. B. Prenn, R. H. Robinson

"The model described is a design and economic planning tool for analyzing surface mineral deposits. Mineralization, topography, costs and significant geologic features are input to the model. The results are:(i) final pit limits yielding the maximum total profit,(ii) annual cut-off grades and plant sizing yielding the maximum present value, and(iii) annual maps of the pit and annual production statistics for the mine, concentrator and smelter.Additionally, summaries are printed of the block mining sequence and cash flow. A special feature is an option to include dump-leaching operations. Stockpiling of material can also be simulated by the model. The model is built around theories of dynamic cut-off grades and a pit design algorithm. The dynamic cut-off grades maximize present value by examination of all economic and physical constraints for the optimum combination. The pit design algorithm is a set of rules formulated to find the maximum value from a special graph. The graph is different from graphs of analytical geometry, being made up of points and arrows connecting some of the points. These graph elements describe the relationship between any point in the deposit and the material which must be mined to get at that point. The model was designed to bring together the interdependent theories of economics, pit design and production scheduling."

Jan 1, 2014

By M. Sciarone, B. Collins

The production, properties, and selection of ferrosilicon powders for heavy-medium separation by B. COLLlNS. B.Sc Eng. (Rand) (Fellow). T. J. NAPIER-MUNN. B.Sc. (Eng.). A.R.S.M. (Visitor). And M. SCIARONE. M.Se. Eng. (Delft) (Visitor). There are basically two types of ferrosilicon powder available to operators of heavy-medium plants in South Africa spherical and milled grades. The production processes are described, and the properties of the two types are examined and compared. Guidelines are given for the selection of the correct grade of ferrosilicon for any particular application.

Jan 12, 1974

By Timo Niitti, Sami Grönstrand

n today's marketplace with high metals prices, many operations are faced with the challenge of improving recovery and at the same time maximizing availability. New operations under feasibility studies have the same requirements, with the additional need for ever higher capacities. Economies of scale have proved a vital competitive advantage in the game of ore dressing. Flotation is the most widely used method for extracting valuable minerals from ore - despite its mature age of 100 years. Customer demand has driven the development to increasing cell sizes, and in most cases, this has brought the advantages of both lower capital expenditure and lower operational and maintenance cost. The challenge of scale up, however, is to meet the metallurgical performance requirements in the larger volumes. The paper outlines recent trends and developments in flotation technology, and presents new solutions designed to address the needs for increased capacities as well as improved performance. Whether the goal is to improve existing operations or to scale up new equipment, computer aided tools are playing a key role in shortening the development cycle and reducing costly trial-and-error tests in full scale. Using the new tools and validation thereof will be outlined, as well as the development principles behind the new solutions. Plant results and experiences with the new developments are presented and discussed in several cases around the world.

Jan 1, 2007