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By K. I. Afewu

A modified approach to the implementation of Gy?s sampling theory is discussed and used to design a procedure for sampling crushed gold ore feed to metallurgical process plants. The approach involves calibration of certain ore-specific parameters. These parameters were calibrated for two different crushed gold ores en route to grinding mills in process plants. The model predictions were compared with the predictions from Gy?s original model. Far smaller masses of samples are required by the modified model than by Gy?s model at the same relative variance. The representativeness of the sampling procedure if normally distributed errors are assumed was also calculated. These procedures and evaluations lead to significant savings on cost of handling and preparation of the samples and to a quantifiable degree of confidence in the analytical results for the process plant.

Jan 1, 1998

By J. H. Potgieter

This paper describes an investigation to separate and selectively recover silver, gold and platinum from jewellery and laboratory wastes, and produce technical grade material suitable for training purposes. Nitric acid was employed to dissolve and separate silver and other impurities from gold and platinum, which were then dissolved in aqua regia and precipitated selectively. The current work quantified the effects of temperature, stirring rate, leaching agent concentration and solid: liquid ratio on the recovery of the various noble metals and in summary yielded the optimum treatment conditions in each case. It was found that increased leaching reagent concentration (in the case of Ag), temperatures and stirring rates enhanced the recovery kinetics and optimum yield of the three noble metals. An increased liquid to solid ratio also enhanced the recovery of the silver. Recovery yields 97.1%, 99.9%and 99.4% for silver, gold and platinum, respectively, were obtained. The recovered silver, gold and platinum had purities of, respectively, 98.3%, 99.1% and 99.0%. A cost saving of approximately R10 000 per kilogram of scrap refined could be achieved by the in-house treatment of the waste, not to mention the time-saving benefit.

Jan 1, 2004

By J. C. Jansen

The platinum mining industry has experienced a significant increase in fatal accidents. Mine accidents are in principle preventable, and there is enormous pressure on employers to reverse this trend. This paper reviews safety management systems (SMS) as well as behaviour-based safety (BBS). Based on the review, SWOT analyses are performed on the SMS and BBS processes and a model of an integrated safety management system (ISMS) is introduced. A number of fatal accidents is analysed to identify factors that contributed to accidents in the mining industry. Thereafter the potential weaknesses of an SMS of a platinum mine are exposed and the potential benefits of implementing the ISMS for this case study are demonstrated.

Jan 1, 2005

By A. Swanson

The Australian coal industry has been subdued in recent years and only a few new plants have been constructed, but the drive for greater efficiency has seen continued technological developments. The paper lists the new plants and major upgrades, plus summarizes technical developments in the areas of dense medium processing, fine coal treatment, froth flotation, dewatering and on-line analysers.

Jan 1, 2001

By E. Yalçin

The data set often contains one or more secondary variables. These secondary variables are usually spatially cross correlated with the primary variable. The addition of the cross-correlated information reduces the variance of the estimation error by using the cokriging method. The grade estimation results of ordinary kriging and cokriging methods are evaluated and it was found that the estimation variance of cokriging method is slightly lower than ordinary kriging. The effect of variation of block dimension on the estimation results is also investigated and it was seen that the cokriging estimation variance values also decrease as the block dimension increases.

Jan 1, 2005

By D. Pillay

Outsourcing? and ?sub-contracting? have become buzzwords in recent years, as SA industry becomes increasingly exposed to the global economy, and global competitiveness. In its effort to ?catch up? after years of relative isolation, there is a concerted effort to learn from global ?best practice?, in order for South African companies, and the SA economy, to become ?winners?. There seems nothing wrong with this approach at face value. Companies need to compete and be profitable if they are to remain in business. Failure will in the end mean bankruptcy, and the loss of jobs. However, if one interrogates the precise practices, and their implications for all concerned?not just shareholders and employers, but workers, communities, the environment, future generations, the national economy?then the picture can change dramatically. ?Best practice? for whom?

Jan 1, 1999

By W. Pulles

Mining can adversely affect water quality and poses a significant risk to South Africa?s water resources. Proactive management of environmental impacts is required from the outset of mining activities in order to reduce this risk. Major strides have been made over the last 7 to 8 years, by both the Department of Water Affairs & Forestry (DWAF) and the mining industry, in developing strategies and management plans for the effective management of water within the industry. This has largely been achieved through the development of joint structures where problems have been discussed and addressed through cooperation. This process, which was started around 1991, has continued through to the present time. The mining sector management strategy has been developed at a number of different levels as follows: ?A detailed Management Plan, that sets out strategic objectives, broad strategies and functional and organizational arrangements. ?Operational Guidelines, that define and document specific operational procedures. ?Technical Guidelines, that define and document best practices for pollution prevention and impact minimization from mining operations. The Technical Guidelines consist of Best Practice Guidelines (BPGs) and Regulations.

Jan 1, 1999

1. A statistical approach to some mine valuation and allied problems on the Witwatersrand. Unpublished Master?s Thesis, University of the Witwatersrand ? 1951. (Separate) 2. A statistical approach to some basic mine valuation problems on the Witwatersrand - J. of the Chem. Metall. and Min. Soc. of S.A., December, 1951 - discussions and replies March, May, July and August 1952. (Vol. 1?.1). Also: J. of the Institute of Mine Surveyors of S.A. December 1952, March 1953. (Vol. 1?2) 3. A statistical analysis of some of the borehole values of the Orange Free State goldfield - J. of the Chem. Metall. and Min. Soc. of S.A., September, 1952 - discussions and reply November 1952, and February 1953. (Vol. 1?3). 4. A study of the relationship between development values and recovery grades on the South African goldfields - J.S.A.I.M.M, January 1959, - discussion and reply April and October 1959. (Vol. 1?6) 5. On the departure of ore value distributions from the lognormal model in South African gold mines. J.S.A.I.M.M., November 1960, January and August 1961. (Vol. 1?8) 6. Developments in the valuation of gold mining properties from borehole results - Seventh Commonwealth Mining and Metallurgical Congress, 1961. (Vol. 1?9) 7. Effective pay limits for selective mining. J.S.A.I.M.M., January and August 1962. (Vol. 1?10)

Jan 1, 2014

By K. Sørli, H. Elstad, I. M. Skaar, A. Hildal

Generally, monitoring of refractory furnace linings is of interest to the metallurgical industry. The main issues are to control wear of the furnace lining and break out of molten metal. Penetration of molten metal through the lining can cause considerable damage to equipment in the vicinity of the furnace and endanger operators. Rebuilding of a furnace lining is expensive, mainly because it stops production, but also because the lining materials are expensive. Here, two methods for monitoring the lining of a smelting furnace are presented. The methods are based on monitoring of the temperature distribution in the lining, more specific monitoring an isotherm in the lining. One method is based on the assumption of unidirectional heat flow locally, reducing the problem to a set of one-dimensional heat conduction problems. The other method is based on inverse heat conduction. In this context inverse heat conduction means estimating the wear from temperature measurements using mathematical optimization techniques. The study is based on the ilmenite smelting furnace at Tinfos Titan & Iron KS. Some results from real temperature measurements and real observations from the ilmenite smelting furnaces is presented.

Jan 1, 2003

By A. H. Swart

Rock engineering is concerned with the design of rock structures generated by mining activities. Therefore, rock engineering designs have major implications for the safe recovery of mineral deposits and operating costs. The paper deals with a few challenges facing rock mechanics engineers operating in the hard rock underground mining environment in South Africa. Finally, examples are included, which may assist rock mechanics engineers in providing better designs, which could ultimately lead to further improvement in safety and lower operating costs.

Jan 1, 2005

By B. Kenny

The aim of this paper is to provide an overview of existing forms of subcontracting in the South African mining industry. A descriptive framework is developed to understand different subcontracting arrangements. We argue that, in order to do so, it is important to distinguish between labour broking and gang subcontracting. Data resulting from a research project (including an analysis of historical sources, interviews with contractors and focus group interviews with mineworkers) is presented to highlight the implications of changing formations of subcontracting for the South African mining industry in the late 1990s. Apart from the subcontracting of ?traditional? functions, such as shaft sinking, access development, catering and hostel maintenance, contractors are now used in ?core? mining activities. In some instances, whole shafts are ?outsourced? to outside agencies. It is argued that certain of the subcontracting arrangements have serious implications for the ability of the mining industry to improve health and safety standards. Some of the practices can potentially result in conflict between different categories of workers, and, as a result, instability in the industry.

Jan 1, 1999

By S. Lin

A new hydrogen production process, named the HyPr-RING, has been proposed. Fundamental concept of the HyPr-RING is integration of water carbon reaction, water-gas shift reaction and CO2 absorbing reaction in a single reactor. Firstly, thermodynamic analysis was done to judge the possibility to realize the process. It was found that high pressure and temperature condition, such as 20 MPa and 1000 K, is required to promote this integrated reaction. Next, experimental verification of the new process was done under the high pressure and temperature reaction conditions. As the results, integration of above three reactions in a single reactor can be done successfully and produced a large amount of hydrogen as estimated by thermodynamic analysis. Experiments showed that organic materials including coal, heavy oil, biomass, plastics can be used in this process. In the gaseous phase, no pollutants such asH2S, SO2, COS are detected so that gas cleanup system is not required for power generation when this process is used. Finally, a process design was made to estimate process efficiency. Theoretically, 1 mole of carbon can generate 2 moles of hydrogen and cold gas efficiency of this process estimated as more than 80 per cent. The process potentially reduces hydrogen production cost compared with the conventional hydrogen production methods. Keywords: Hydrogen, Fossil fuel, Energy, Process, Supercritical water

Jan 1, 2001

The typical reactions which the reductants undergo during ferroalloy production are reviewed, and identified as reaction with CO2 and with SiO, and dissolution in metal. Available reactivity tests for these three reactions are reviewed. It is proposed that it is worthwhile considering dissolution kinetics as a reactivity parameter. Greater crystallinity of the reductant decreases CO2 and SiO reactivity, but increases dissolution rates.

Jan 1, 2002

The paper deals with the importance of design and of codes of practice in ensuring safe working conditions in mines. The design principles involved in the design process are dealt with, and the importance of a logical design process is emphasized. The links between the requirements for developing a code of practice, embodied in the existing guidelines for the preparation of such a code, and the design principles and process are considered in some detail. Finally, suggestions are included, which may provide improvements to the code and hence, ultimately, lead to further improvement in safe working conditions.

Jan 1, 2004

By Y. Poornachandra Rao, P. C. Sudhakar, L. Malakondaiah

NBV commissioned a 27.6 MVA furnace in the year 2005. This paper explains: a)Furnace design features b)Furnace process control, Direct slag granulation c)Continuous casting, Waste heat recovery, Sintering d) Gas cleaning plant, Protection of Environment. Keywords: Furnace Equipment, SiMn Production, Casting, Heat Recovery and Low hood

Jan 1, 2007

By G. Konak

In-pit crusher location selection has had an important role recently, since increasing diesel prices. One way of reducing the haulage costs is to shorten the truck haulage distance by bringing the truck dump point into the pit. This study covers the work done on the optimum crusher location definition for a company that produces aggregate near Izmir, a city of Turkey located in the west. This paper will discuss the effects of pit geometry and mine access requirements on optimum crusher location selection that are mainly based on the establishment of minimum haulage distance. The method will be introduced first and then the computer algorithm developed for this study will be discussed later in the paper. Keywords: in-pit crushing, optimum location selection, optimizing haulage, computer aided design.

Jan 1, 2007

By P. T. Slatter

The efficient and accurate design of pipe and pumping plant for non-Newtonian mineral slurries remains a problem. The objective of this paper is to present the development of the Balanced Beam Tube Viscometer (BBTV), an instrument which could facilitate more accurate design for these slurries. The background of rotational and tube viscometry is reviewed and the fundamental principles and inherent advantages of the BBTV are given. The design, data acquisition and processing techniques are introduced and results showing the reliability of the new instrument are presented and discussed. It is concluded that the BBTV is a reliable and versatile instrument for both routine analyses and research work, and has the potential to provide data for the refinement of the design procedure for mineral slurry pipe and plant design.

Jan 1, 1998

By S. Marsland

Reference materials have always been important for validating and controlling analytical methods. They have recently become even more important as quality requirements have become more stringent and customer demands for properly verified and controlled results increase. Clients, especially from the resource exploration industry, demand critical validation of all results reported. Mintek has been producing geological and semi-processed ore references since the early 1970s and recently, due to increase in demand, other manufactures have entered the South African market. This paper describes analytical challenges from the customers? perspective, the customers being metallurgists, mine geologists, environmental scientists and geologists from resource companies. Reference materials with their appropriate use and a good understanding, can aid greatly in building confidence in the results, choosing the right laboratory for a project, deciding which set of results is correct and providing evidence to the customers? clients that the best possible results have been obtained

Jan 1, 2007

By G. Bacon

The past decade has witnessed unprecedented growth in the development and implementation of solvent extraction technology in the extractive metallurgy of nickel and cobalt. Solvent extraction is proving to be a powerful tool, opening new opportunities for simpler, more cost efficient and environmentally sound metal refining processes. These advances, however, could not have been possible without the cooperative efforts between the nickel industry and the people and organizations involved with reagents, materials and equipment development and supply as well as solvent extraction research, aided by the accumulated knowledge and practical experience from the copper and uranium solvent extraction operations. This paper provides an overview of these developments and some of the challenges ahead.

Jan 1, 2002

By G. A. Brown

Major mining projects are developed with the assistance of lending institutions who provide hundreds of millions of dollars in funding over several years, and of course expect those funds to be returned with interest. Two Australian banks have adopted the Equator Principles, an emerging financial industry benchmark for assessing and managing environmental and social risk in project financing. Project financiers have encountered environmental and social issues that are both complex and challenging, particularly with respect to projects in the emerging markets of Asia-Pacific and elsewhere. There are many recent and historical examples of failures by resource companies to effectively manage their environmental, social, safety and security risks, some of which have caused the project to fail completely, and some of which have caused the temporary cessation of production. These events put the financial institutions' funds at risk through inadequate management capacity and non-compliance adversely affecting the ability of the borrowers to repay the loans. They can also reflect adversely on the reputation of the lending institutions. In assessing these risks, lenders are increasingly looking at the track record of the borrower in its country of origin and in other countries where it operates. Lenders are wary of companies that have one standard for operations in a developed country, where the regulatory environment may tightly control what they do, and another standard for operations in countries where the regulatory regime is perhaps less stringent. Lenders may require environmental and social reviews or audits to be conducted on their behalf by competent third parties prior to a loan being approved, and annually over the life of the relationship. The mining industry's concept of the unwritten `social licence to operate' is highly relevant in relation to the delivery of community benefits that are sustainable post-mine closure. This paper provides examples of recent practices that support financial viability and sustainable development, as well as examples of some failures that have put lenders at risk.

Jan 1, 2007