Search Documents

By B. Rainier

This paper discusses the preparation of material for backfilling operations using hydrocyclones. Aspects dealt with include the advantages and disadvantages, material requirements, process constraints, operating systems and equipment of the backfill plant.

Jan 1, 1988

By W. K. C. Boemer, G. A. Davies

Vanadium slag production in the shaking ladles started in April 1968, steelmaking was begun in July 1968 and the first continuously cast blocks were produced soon after on the 29th July, 1968. Nominal monthly production of over 20 000 tons was reached in seven months and by December 1970 about 12 000 heats were cast and a monthly production of 35000 tons has been achieved.

By P. van Niekerk, V. J. Solomon

Improvements in the drilling and blasting techniques used in the stopes of narrow reefs have caused the clearing of broken rock to become the major cause of delay in the achievement of a regular cyclic operation. This paper discusses the development of a scoop in accordance with a predetermined set of performance parameters. The test results obtained to date have shown that the basic objectives have been achieved within tolerable limits of variation.

Jan 1, 1979

By H. V. R. Von Rahden

The expertise of the industrial mineralogist has not always been sufficiently used in decision-making in the minerals industry in South Africa. The mineralogist can make a contribution at al stages of the exploration programme, from the time of discovery of a geological target area, through metallurgical testwork and pilot-plant studies, to the production of a saleable product. This indicates that the activities of the industrial mineralogist should be more closely integrated with those of the exploration geologist and the extraction metallurgist in order to provide management with a meaningful picture of the economic potential of an ore deposit.

Jan 1, 1997

By P. F. S. Jackson, A. Strasheim

In the survey "Analysis of South African raw bullion" the distribution of trace elements within the bullion have been shown to be distinctively dependent on the extraction process. In general the amalgamation process produces the more impure bullion with respect to trace elements. Some chemical and physical explanations are given for the differences that have been observed in the raw bullion as received at the Rand Refinery. The value of the spark source mass spectrographic technique in the study of the elemental impurities in bullion is demonstrated.

By G. M. Bentel, G. E. Blight

The environmentally acceptable disposal of fine-particled mining and industrial wastes by the formation of hydraulic- fill slimes dams is becoming an increasingly important aspect of the total mining endeavour. Relatively little is known of the behaviour of waste slurries during deposition. This paper describes and analyses the following aspects of slurry behaviour: (i) the relationship between viscosity, shear strength, and water content, (ii) the slope assumed by a thickened slurry, (iii) particle-size sorting on a hydraulicfill beach, (iv) gradients of hydraulic-fill beaches, and (v) internal erosion during the deposition of slurry. v083n04p073.pdf

Jan 1, 1983

By Peter Smith

The construction of one of the world'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 H. E. Parkinson, Y. P. Chugh

About 90 percent of the coal mined underground in the U.S.A. today is mined by the room-and-pillar system. The productivity of the system dropped from about 14,1t per man-day in 1969 to about 7,3 t per man-day in 1978. Since 1974, the U.S. Department of Energy (formerly the U.S. Bureau of Mines) has been engaged in research to improve the production and productivity of the room-and-pillar system. The effort involves the development of integrated, automated, and remote-controlled equipment and systems including remote-controlled continuous miners, automated miner-bolters, automated extraction systems, continuous haulage systems for use behind miners, and remote-controlled equipment for miners, bolters, and shuttle cars. These systems are discussed briefly, the discussion being related primarily to coal winning, although the concepts could be utilized in room-and-pillar systems in mines other than coal mines.

Jan 1, 1981

By P. E. Venteer

The Grootegeluk coal-processing plant treats 3 kt of raw coal per hour to produce a middlings fuel coal and a coking coal fraction with ash contents of 35 and 10 per cent respectively. The plus 0,5 mm fraction is treated by heavy-medium processes, the final top size of the coal being 15 mm. About 400 t of minus 0,5 mm coal per hour is subjected to froth flotation. The routes originally considered for the processing of this fine coal were froth flotation, shaking tables, heavy-medium cyclones, and water only cyclones in combination with froth flotation. The results from tests on the fines arising from a small-trial open-cast mine are discussed. When the froth flotation route was decided upon, further tests were conducted on the selection of the equipment most suited to the particular requirements of this coal and the rest of the plant. Tests using different types of flotation cells and dewatering equipment are discussed. During the commissioning, several operational problems were encountered, and the work done to find the best solutions is discussed.

Jan 1, 1984

Caving is the lowest cost underground mining method provided that the draw point spacing, draw point size, and ore-handling facilities are designed to suit the caved material, and that the draw point horizon can be maintained for the life of the draw. In the near future, several open-pit mines that produce more than 50 kt per day will have to examine the feasibility of converting to low-cost, large-scale underground operations. Several other large scale, low-grade underground operations will experience major changes in their mining environments as large dropdowns are implemented These changes demand a more realistic approach to mine planning than in the past, where existing operations have been projected to increased depths with little consideration of the change in mining environment that will occur. As economics force the consideration of underground mining of large, competent ore bodies by low-cost methods, the role of cave mining will have to be defined In the past, caving was generally considered for rockmasses that cave and fragment readily. The ability to define cavability and fragmentation, the availability of large, robust load-haul-dump units, a better understanding of draw-control requirements, improved drilling equipment for secondary blasting, and reliable cost data have shown that competent orebodies with coarse fragmentation can be exploited by cave mining at a much lower cost than by drill-and blast methods.

Jan 1, 1994

By S. Carter

this paper describes an innovation in computer software that permits mining professionals to collaborate on exploration and mining projects regardless of geographic location. Growth of mining companies through merger and acquisition has created a greater need for mining professionals to collaborate, especially as projects and project participants are becoming geographically remote. Surpac NetVision, the name given to this new collaboration technology, satisfies this need by deploying interactive 3D graphics sessions across computer networks. It achieves this by using common web browser technology as the deployment medium. A plug-in architecture that supports diverse file formats permits transparent read and write of foreign data to further enhance the collaboration process. Surpac NetVision supports any number of connections from web browsers on remote computers using existing networks. Software components required to enable the collaboration session are deployed to the remote computer as required and cached for future sessions. The collaboration session at each computer is characterized by a fully functional replica of the user interface for Surpac NetVision from which any function can be executed by any client, at the owners discretion. All geometry and display attributes deployed to remote clients to render 3Dgraphics are highly compressed to reduce bandwidth requirements. The key benefits of this collaboration technology is improved communication in regard to exploration and mining projects leading to: •More informed decision making •Improved deployment of project objectives and plans beyond the technical planning group to project management and operations staff •Improved technical support for software users. Keywords: 3D graphics, project collaboration, interactive graphics, internet 3D graphics, mining software

Jan 1, 2003

By HORNICKA OSTRAVA

The Czechoslovak Scientific-Technical Institute has arranged the international conference 'Hornicka Ostrava' for four or five days at the end of October, 1969, as part of the preparation for the international 'Miners' Congress' on deep coalextraction in 1970. The keynote of the conference is 'New Techniques in coal mining,' and will be covered by five groups dealing mainly with: 1. New trends in the opening of mines, optimal parameters, projections, equipment, utilization of computers for economic analyses, etc. 2. Increase in efficiency of coal extraction in deep mines, technology, concentration, pressure control, optimization of material and coal transport. 3. Modernization of devices for increased safety and working conditions, new trends in explosives, new techniques for reducing environmental diseases. 4. Innovations in deep level coal extraction, mechanization, rationalization, automation, etc. 5. Other topics about modern techniques in mining. Address your enquiries to: Ing. Karel Kalas (Secretary of the Conference), Dum Techniky Cs YTS, Ostrava 1, Jesenkiho 7-9, Czechoslovakia.

By Y. R. Murthy, P. K. Satija, A. Srinivasulu, S. K. Tripathy, A. Ranjan

"In this investigation, we optimize the grinding circuit of a typical chromite beneficiation plant in India. The run-of-mine ore is reduced to a particle size of less than 1 mm in the comminution circuit and concentrated using gravity separation. The comminution circuit comprises two-stage crushing and single-stage grinding in a ball mill in closed-circuit with a highfrequency screen. A detailed circuit audit was undertaken at the plant to understand and evaluate the performance of the grinding circuit. The audit revealed abnormalities in the process and design parameters which caused high energy consumption, lower throughput, and loss of ultrafine chromite. Laboratory studies indicated the differences in the grinding properties (work index, breakage rate, etc.) and liberation sizes of these ores. Studies also revealed that grinding media size, particle retention time, and pulp density are crucial in coarse grinding. Based on the laboratory grinding and characterization studies; simulation studies were performed to optimize the operating parameters of the grinding circuit.IntroductionComminution is a critical process in mineral processing which strongly influences the economics of production. In mineral processing, particles containing valuable minerals must be disintegrated at a sufficiently fine size to liberate valuable minerals from waste constituents, so that they can be easily separated by an appropriate beneficiation method. The Sukinda chrome ore beneficiation plant utilizes different types of run-of-mine (ROM) ore with different physical properties (viz. grindability characteristics, work index, mineral composition, liberation, chemical composition, etc. for the production of chrome concentrate. In the feed preparation circuit, the ROM ore is crushed and ground to below 1 mm. Grinding in the chromite beneficiation plant is a critical unit operation to achieve the desired product size of below 1 mm and to control the generation of the ultrafine particles. Furthermore, about 40% of total power consumption in the beneficiation plant is accounted for by the grinding of the ore. This implies that any improvement of the circuit performance will lead to an overall increase in productivity."

Jan 1, 2017

By C. L. de Jongh

The number and scale of backfilling operations in the South African gold mining industry have grown rapidly in recent years. The application of backfilling as a means of stope support in a wide range of geological conditions and mining systems has resulted in the development of a variety of alternative fill systems. Experience gained in the evaluation of operating fill systems has contributed to a knowledge of the essential concepts to be considered in their design. This knowledge can also influence management's perception of what is expected of a backfilling system. The factors to be assessed in stating and satisfying these objectives are examined. The areas of investigation cover the selection of a suitable material, its preparation, distribution and placement, and the engineering logistics involved in the management of such a system. Finally, the integration of a filling system with an existing mining operation is examined.

Jan 1, 1988

By T. Puhakka

Simulation is a way to obtain quickly today future information on how planned systems will most likely behave in various selected situations. This information may then be used to optimize the system and its components and maximize the performance and output. Simulation is a way to fine-tune the layout, match the mobile fleet and optimize the schedule and the way of working to meet the desired production requirements. Simulation provides a glimpse of the upcoming operation, ‘future today’ and helps to predict its restrictions and sensitivity to various aspects. OptiMine™, the Sandvik Tamrock Corp. and CyberCube Oy developed simulation tool is designed to simulate underground rock flow and match suitable technology with various layout options. This tool can be used to view what-if situations and determine what kind of impact mastered changes have to production. The findings of critical points in the layout and working procedures at an early stage of a new mine can help to optimize the layout and material flow. OptiMine™is modular based simulation tool that combines the supplier machine knowledge and traffic guidance with mine operational know-how and mine environment. It is developed to work in a way that an effect of an individual incident, such as the effect of one additional turn in a continuous loading cycle to the daily capacity can be identified. The reported output can be used for economical impact evaluation of selected options. This paper discusses the use of simulation in general and the way the OptiMine™ simulation tool operates and how it may be used for operation, technology and material flow optimization.

Sep 1, 2001

By G. D. Schena

The issue of evaluating the economic impact of large mineral projects in developing countries was studied by the use of econometric models. The evaluating system is demonstrated by its application to an example from Namibia. Three-dimensional graphics are used to illustrate the procedures leading to an assessment of the economic effects of the mineral development. The analysis allows the assessment of the overall economic consequences of mineral developments where there is a need to incorporate in the evaluation issues that are broader in scope than the pure financial objectives. Sets of technical coefficients are exploited for the development of input-output models of the productive structure of an economy. The models are refined to incorporate country-specific behaviours. The increased flexibility of the enhanced semi-input-output model permits a more confident investigation of the economy wide effects associated with a new project in the mineral sector of a developing country. Synthetic measures of profitability at market and shadow prices are introduced, and the cost/benefit ratio is used to rank mineral projects according to their economic profitability. The cost is the capital mobilized for the development of the project and for increasing the productive capacity of the related satellite industries. The benefits are identified with the economy-wide increase in value added induced by the project. 80th costs and benefits are initially valued at market prices. Their ratio is likely to be an index of economic profitability superior to measures that concentrate exclusively on the benefit side of projects. To allow for market distortions, the concept of shadow prices is introduced, and accordingly project-related costs and benefits are re-evaluated. A new cost/benefit ratio at shadow prices is recalculated, which is more meaningful to the policy-maker than decision-making based on socio-economic issues.

Jan 1, 1993

By K. L. Morton

This technical note reviews the status quo of mud rushes and flooding, which have claimed them lives of many people in underground mines in South Africa and globally. Given that the causes are well known and can be managed, the note calls for the development of a national and global standard on flood and mud rush prevention in order to save lives.

Mar 30, 2026

By A. García-Gutiérrez, A. Aragón-Jerónimo, R. Salazar-Mendoza

A theoretical analysis of a two-region solid-liquid flow system in horizontal pipes is presented, which considers a stationary bed of drill cuttings as a porous medium (-region) below of a two-phase dispersed flow (-region).The method of volume averaging was applied in this study to derive a rigorous mathematical model in which each variable is precisely defined. This model includes the volume-averaged transport equations for both the two-phase dispersed flow and the porous medium regions and terms from a macroscopic forces balance. The solution of the two-region model allowed evaluation of the behaviour of pressure gradient as a function of velocity, total volume fraction of cuttings and the relationship of the height of the stationary bed and pipe diameter. The solution is based on a backward finite difference explicit scheme. The simulated physical system is a pipe of 4.135 m in horizontal length and 0.0508 m in diameter. A one-dimensional, mesh-centred grid, consisting of 100 nodes, is used. The numerical results were compared with experimental data on slurry flows and a good agreement was found. Keywords: two-phase, cuttings transport, solid-liquid flow, drilling modelling, volume averaging.

Jan 1, 2007

By R. Falcon, A. J. Ham

This paper summarizes the characteristics of Southern African coals, presents a fundamental approach to the combustion performance of coal, and reviews some of the recent developments in the fields of technological evaluation and boiler design for coals typical of this region. This includes a summary of the petrographic constituents of coa~ highlighting the differences between the Palaeozoic coals of the northern and southern hemispheres (Laurasia and Gondwana respectively), and the effects of these properties on the combustion performance of coal as seen in terms of laboratory, pilot-scale, and full-scale operating conditions. Recent developments in boiler design linked to advanced characterization studies and commercial experience have led to unprecedented use, with maximum effect, of the low-grade, high-ash, high-inertinite coals typical of some parts of this region. In the light of this success, more adequate understanding and better methods of assessment of the coals typical of the Gondwana region are called for, particularly in the light of the price premium for high-grade coal and the more cost-effective lower grade coals on the international steam markets.

Jan 1, 1988

By D. D. Marsden

This paper discusses the concentrations of sulphides and total sulphur in widely spread regions around mine residue deposits, from which rain-water run-of can enter the Vaal River system. Analyses of borehole samples from several deposits are used to establish typical sulphur head grades. It is shown that a high percentage of al the oxidizable, and hence leachable and pollution-causing, sulphur has already been removed. When the residues were fresh, water that came from the deposits was highly polluted, but the dissolved solids from these residues are today of very minor significance. The data are supported by analyses of the drainage streams.

Jan 1, 1986