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By Z. Levinson, R. Dimitrakopoulos

A mining complex is an engineering system where raw materials are extracted from several mines, processed, transported, and sold to the market. The uncertainty and local variability of material grades and their locations within the related mineral deposits are critical for determining the optimal life-of-mine extraction sequence, destination policy, operating modes, and capital investment decisions, which define the production schedule of a mining complex. Infill drilling is used to further characterise a mineral deposit and reveals information that changes the representation of the resource model and potentially the resulting optimal long-term production schedule. A self-learning reinforcement learning approach is proposed to determine the optimal drilling locations that maximise the net-present value of the long-term production schedule and the associated financial forecasts by adapting the schedule to additional information. A case study at a copper mining complex demonstrates a $70 M increase in project value by collecting drilling information with a $1 M budget.

Sep 1, 2021

By P Clive Hart

DRA - BACKGROUND [MULTI MINERAL DESIGN & BUILD COMPANY FOUNDED 1984 ENGINEERING FOCUSED CORE ENGINEERING DISCIPLINES INCLUDE: ?PROCESS ?MECHANICAL ?E&I CONTROL PRIVATE COMPANY, INDEPENDENT & INTERNATIONAL]

Jan 1, 2006

By H. A. D. Kirsten

SYNOPSIS This paper describes simple calculations to evaluate the stability of hangingwall and footwall strata at the work¬ing face and in backfilled areas. It shows that the benefits of support provided by backfill can best be realized when the fill is placed as close to the face as possible. The main beneficial effects of fill are that it reduces the stope span, at the same time providing a damping effect on vibrations, and prevents the fall-out of blocks in filled areas, thus maintaining the competence of the strata.

Jan 1, 1988

By P. Kind

Design criteria and recent developments in large-capacity Wemco flotation cells by P. KIND, Ph.D. (Clausthal), B.Sc. (Visitor) The scaling-up of the large flotation cells that have been developed during the past few years has been based on hydrodynamic considerations and has resulted in a 500 ft3 cell unit. Plant results on a porphyry copper ore show that the 500 ft3 unit is equivalent to the previously used 300 ft3 model.. . Plant tests on the use of 300 ft3 flotation cells for the recovery of phosphate, particularly from the coarse size fractions, are also described.

Jan 3, 1976

By R. M. Stroh, D. F. H. Grave

In this paper ventilation planning methods are discussed, with particular reference to the application of computer techniques to the solving of the many problems associated with the forecasting of ventilation and refrigeration requirements in mines of high production rates going to depths and rock temperatures higher than previously experienced. The use of the Starfield-Dickson programmes for calculating heat flow into airways and advancing stopes is demonstrated in the case of ventilation planning on a large mine extending to a brief depth of over 3 km below the surface. The possible effects of new mining methods on ventilation requirements in the future is briefly discussed.

By Christopher J. Oates

Overview ? Mining Codes ? Best Practice ? Mining Standards Guidelines ? Get it right from the start ? External Auditors ? The 5% rule ? MMCRM's - The Key Components ? The MMCRM Report / Certificate ? MMCRM's & Round Robins ? Summary

Jan 1, 2005

By H. W. Read, L. G. D. Napier

Change is endemic in our society. Future change will be accelerated by an explosion in technology, communication, and political thought. To meet these challenges, rapid structural changes have been taking place in mining organizations both here and abroad. The management of shaft-sinking projects is a case in point. Shaft sinking is a seminal element in the sustained well-being of a deep level mining venture. Its accomplishment is fraught with risk, involves a high level of capital expenditure, and is a precursor to profitable mining investment. The purpose of this paper is to present a concise and practical picture of the concepts, methods, and techniques of professional project management as applied to shaft-sinking projects.

Jan 1, 1994

By F. S. A. de Frey

The main users of computerised financial evaluation tools in the mining industry are the mining investment analyst, the mine manager together with his financial manager and the mining student (undergruadate and post-graduate). The mining investment analyst's needs mainly centre around the-micro and macro aspects affecting the mining industry in general. The mine manager needs a tool to assist him with the planning, reporting and controlling of production, costs, efficiency, productivity and cashflow. For the mining student studying Financial Evaluation, the main need is for a computer program which will assist him in learning the basics of the subject. This paper concentrates on the needs and objectives of the course Financial Mine Evaluation, the approach to which is presented. Emphasis is placed on the practical computing sessions and the role of the FCS-EPS package as a training tool.

Jan 1, 1987

By H. Jeram

The ilmenite, rutile and zircon processes of the mineral separation plant generate tailing streams, which still contain valuable mineral. This is due to a combination of factors, which include separator equipment efficiency, particle size effects and inefficient operating practices (equipment overloading, blockage, etc.). Recent developments by metallurgical equipment suppliers have led to increased mineral separator performance enabling recovery of previously lost valuable mineral. Mineralogical studies were conducted using QEM*SEM and MLA techniques to identify and quantify gangue mineral species and determine mineral association. Laboratory and pilot-scale test work was then conducted to develop suitable process flowsheets for the recovery of ilmenite, rutile and zircon from current and stockpiled tailings.

Jan 1, 2007

By F. Lombard

We consider in this paper the use of a modified version of Hotelling?s statistic in the analysis of particle size distributions. The statistic can be adversely affected by the presence of outliers among the data. We propose a competitor to the statistic that is based on ranks, and hence is less sensitive to outlier effects. The results of a Monte Carlo study suggest that the rank test is highly competitive with the Hotelling test in its ability to detect differences between two mass size distributions. The calculation of the rank statistic is explained in detail and its application is illustrated on two sets of data.

Jan 1, 2012

The special mixing requirements for backfilling are discussed, and the problems associated with the mixing of coarse and deslimed slurries, as well as the tailings from the gold plant are outlined. The mixing of binders which are used to strengthen backfill and the parameters for the scale-up of mixer pilot plant work are also discussed

Jan 1, 1988

By F. Lombard

We consider in this paper the use of a modified version of Hotelling?s statistic in the analysis of particle size distributions. The statistic can be adversely affected by the presence of outliers among the data. We propose a competitor to the statistic that is based on ranks, and hence is less sensitive to outlier effects. The results of a Monte Carlo study suggest that the rank test is highly competitive with the Hotelling test in its ability to detect differences between two mass size distributions. The calculation of the rank statistic is explained in detail and its application is illustrated on two sets of data.

Jan 1, 2012

By D. Francois-Bongarcon

The ?Poisson effect? is defined and characterized. It takes place even when the material to sample is not liberated. Gy, Pitard, Ingamells, and others, including the author, recommend that a minimum average number of particles of mineral of interest characterize the recommended sample size. How many? Recommended numbers range from 6 to 40 particles depending on authors, corresponding to standard deviations of 41% to 16%. Some guidelines are proposed, and the often alleged ?double-Poisson? effect is examined.

Jan 1, 2009

By H. Scott-Russell

Much of the technology and methodology extensively employed in current mining operations is in the mature phase of its lifecycle and, consequently, subject to the principle of diminishing returns. It is probable that future gains in productivity and safety of the magnitude essential for the sustained economic viability of the industry will be derived only from a determined technological development programme. The history of trackless mechanized mining, which represented a radical change in methodology in deep-level gold mines, is reviewed. The benefits and obstacles to the realization of the full potential are highlighted. Similarly, an overview is given of alternative mechanization developments in South Africa. In addition to the development and application of advanced technology, an envelope of operating parameters relevant to each methodology must be engineered to facilitate the site-specific selection of the most appropriate. Furthermore, a mechanism for the evaluation of cost effectiveness is essential to the decision-making process. The narrow, tabular orebodies of relatively low dip that are encountered in the South African hard-rock mining industry make the design and manufacture of a comprehensive range of stoping equipment extremely difficult. The machinery that has been available to date has demonstrated only limited site-specific success. The development of suitable machinery must necessarily be initiated and driven by the South African mining industry in collaboration with the major equipment manufacturers in the world.

Jan 1, 1993

By H. G. Mosenthal

In any mining enterprise, the extraction of the ore from the orebody is of vital importance. This activity is stoping. The gold mines of the Witwatersrand and its extensions in the Klerksdorp, Welkom, and Evander areas form the most extensive goldfield in the world. This address reviews stoping technology and improvements in this technology since the end of the Second World War. Although the reefs that make up the Witwatersrand orebody are uniquely extensive, they are not suited to mechanized mining. This is due to a number of factors such as the depth of the orebody, its narrowness, and the hardness and abrasiveness of the quartzite forming the orebody. The most notable improvements in stoping technology have been brought about because of our beter understanding of rock-engineering problems. This has resulted in beter layouts, stoping geometry, systems of aleviating rock stresses, and support systems. It has enabled the industry, at ever-greater mining depths, to maintain and even increase productivity. These improvements, based on rock engineering, have significantly reduced the accidents due to rockbursts. There are many diferences between today's stoping and that practised forty years ago. Panels are shorter, concentrated mining has superseded bench mining, and the support systems are certainly better. Yet the face scraper is still used extensively, as are pneumatic rock drills. Some innovative stoping systems that have given rise to improved productivity are discussed. Explosives technology has shown spectacular advances during the period under review. Sadly, our local industry has had little to do with this research and development, but has been most adaptive in using the new products on offer.

Jan 1, 1990

By A. Montini

The problems encountered in the design of control systems for milling cir- cuits when the model of the system and the model parameters are uncertain are discussed. Considering these uncertainty factors has led to the development of a technique that gives a quantitative assessment of real system stability, reveals the trade-offs between performance and stability and helps the designer in deciding what level of model complexity to use in the controller design. Furthermore, it allows for on- or off-line optimization of the milling circuit performance as it provides the base for the design of a controller which is stable over the plant operating range.

Jan 1, 1987

By H. Wagner

It is a great privilege for me to have been asked to present the closing address to this most successful symposium on backfill in the South African mining industry. When I accepted this invitation I did not fully appreciate the tremendous progress made on most aspects of backfilling in the last few years. The number and quality of papers presented at this symposium bear testimony to the mining industry's determination and success in introducing backfill in underground mines to improve strata control and environmental conditions, and to provide better protection to mineworkers against the hazards of rockbursts and rockfalls. Many contributions demonstrated that these benefits can be achieved at a reasonable cost, and in some instances improved grade and higher rate of face advance result in improved economics. In my closing address I will attempt to summarize the progress made in the various aspects of backfilling underground workings and to identify those areas which, in my opinion, require further attention and effort. I will undertake this review under the following main headings: ? fundamentals of backfilling; ? design of backfill systems; ? operation of backfill systems; ? control of backfill systems; and other aspects of backfill systems.

Jan 1, 1988

EMMES Sampling Conference BACKGROUND & INTRODUCTION ?Impala acquires toll material to supplement production from ROM ?Toll material consists of filter cake, slurry and catalysts ?Samples are collected to determine the commercial values of the lots ?Slurry deliveries projected to remain relatively constant at 120tons dry solids per month, whereas filter cake deliveries set to increase five-fold to 800 tons dry solids per month ?Due to projected increase in toll material, new sampling and offloading facility presently under construction at Impala ?Presentation will cover two projects aimed at reducing the uncertainty associated with sampling of toll deliveries ?i.e. slurries and filter cake.

Jan 1, 2005

By G. E. Blight

Many mines engaged in deeplevel gold mining in South Africa are experimenting with the use of tailings fills, or are implementing tailings backfilling programmes on a limited scale. The approach varies from mine to mine, depending on circumstances and available fill materials. Several mines are backfilling with a cyclone underflow product; the cyclone overflow is then combined with the balance of the tailings stream and directed to surface disposal. As the extent of backfilling increases, the proportion of the surface tailings stream composed of overflow material will rise, and the properties of the tailings requiring surface disposal will approach those of the cyclone overflow. As the latter will be finer, less permeable and possibly weaker than the total tailings currently being disposed, the design and operation of surface tailings dams will have to be modified. Dams may have to be designed with flatter outer slopes of a reduced maximum height. Lower rates of rise may be required and, as a consequence, larger disposal areas may be demanded. To offset the negative aspects is the fact that the quantity of tailings requiring surface disposal will be reduced. The paper explores the dam-building properties of two cyclone overflow products. It shows that although these materials are inferior in dam-building characteristics to the corresponding total tailings, their geotechnical proper- ties still fall within, or close to, the range of properties typical of gold tailings. Although the design and operation of tailings dams may have to be modified, existing technology is adequate to handle these changes.

Jan 1, 1988

By A. H. Mokken, G. K. I. Blendulf, G. J. C. Young

A study of the arrangements for pulp discharge on pebble mills, and their influence on mill performance by A. H. MOKKEN, B.Sc. (Eng.) (Rand) (Fellow), G. K. I. BLENDULF, M.Sc. (Stockholm) (Member), and G. J. C. YOUNG, B.Sc. (London) (Member) Although used for many years in the gold-mining industry, the conventional pan lifter at the discharge end of a pebble mill has hindered attempts at optimization of speed of rotation and pulp flow. A theoretical approach to flow patterns in pan lifters has pointed to limitations in the capacity of these lifters, with capacity decreasing as speed of rotation is increased. Complete elimination of the pan lifter by the adoption of peripheral or end discharge has resulted in a marked increase in pulp flow and an improvement in power utilization. Assays of the gold content of pulp discharged after a mill stoppage from mills fitted with pan lifters show values well in excess of the current milled grade, which indicates an accumulation of gold particles in the mill and, therefore, a longer retention period. The same could apply to other heavy minerals and metals present in the ore feed or worn off mill linings and metallic grinding media. Examples are osmiridium, fine iron and iron alloys, and copper and sulphide minerals. This phenomenon is attributed to the higher specific gravities of these metals and minerals, causing them to migrate towards the mill shell, from which position they are not readily removed by the lifters at the discharge end of the mill. The close association of gold particles with iron and sulphide minerals in the crevices of mill liners might be conducive to the formation of coatings on the gold. Assays of samples of milled pulp taken from a mill designed for end discharge show a lower accumulation of gold. The accumulation and nature of these gold particles are being studied at present. With increasing diameters of pebble (or autogenous) mills, peripheral or end discharge appears to be the preferred method of pulp removal.

Jan 5, 1975