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By M. Wu, X. Zhao

This paper presents an integrated pipeline transport system for thickened coal sludge, which combines pretreatment and pipeline transport with combustion techniques of thickened coal sludge. The pipeline can transport thickened coal sludge with a sufficiently high solids content (about72%?77%) and high apparent viscosity (about 1 000Pa?S?3,000 Pa?S) directly by pipeline having neither use for water nor an addition agent. The transport distance can be as high as 1 000 metres. In particular, the operating principles, key equipment and technical parameters of this integrated system are examined in this paper. The integrated system effectively causes no pollution to the environment because it is completely sealed, and conserves energy over traditional conveyer designs. Keywords: pipeline transport; integrated system; circulating fluidized bed boiler; thickened coal sludge; high solids content

Jan 1, 2007

The influence of Harold Hotelling?s work in the field of mineral economics is both unusual and outstanding. In the 66 years since its development, theory surrounding the economics of exhaustible resources has only been significantly researched since the early 1970s. At that time a wave of research into the economics of exhaustible resources arose from the threat of global resource scarcity and continued into the late 1990s. Current East Asian and global demand for natural resources as well as mineral and metal commodities, has stimulated interest in the optimal and sustainable exploitation of exhaustible resources to the point that the subject is worthy of review. Hotelling?s theory and the assumptions that he made in establishing a model for the optimal exploitation of mineral resources at the industry level and at the level of the individual mine owner, are examined. He showed that the rate of increase inexhaustible resource prices should be equivalent to the market rate of interest and that in a market with rising prices the rate of extraction should be constant. In markets where demand is stable optimal exploitation requires that the rate of extraction should decline over time, while in a monopoly market he showed that the rate of extraction is retarded. In addition, the effects of cumulative production on costs and prices, the uncertainty associated with estimates of the resource stock, the impact of exploration and issues of intergenerational equity are examined. An analysis of the optimal price path, extraction costs and mineral rents at an industry level is presented as a model. An analysis of the rates of production and optimal benefits at the individual mine level including total, average and marginal costs on the optimal rate of production, is considered. Optimal extraction rates for a mine with a clearly defined concave positive cost equation vary according to the position on the marginal cost curve. The influence of discount rates and the size of the ore reserves on the rates of mineral extraction are also examined and could define the frontier of usefulness for the ?economics of exhaustible resources?.

Jan 1, 2007

By D. Limpitlaw, A. Alsum, D. Neale

"Ecological footprint analysis (EFA) was first described in 1996 as a measure of carrying capacity appropriated by human activities. EFA is a resource and emissions accounting tool designed to track the demand on the biosphere’s regenerative capacity. Ecological footprints are increasingly used as indicators of organizational and corporate environmental performance and product sustainability. There is a compelling argument to develop an EFA tool for mining companies.To determine the size of a mine’s ecological footprint, land requirements for all categories of consumption and waste discharge must be summed. This land is only made up of the ecologically productive land and water in various classes (cropland, pasture, forests etc.) required on an ongoing basis to provide all energy and material resources consumed and absorb wastes.A challenge in conducting an EFA for a mine is the shortage of accessible data. Undertaking an EFA for a corporation or individual site entails compiling consumption and emissions data (which can be used for other reporting applications). The footprint results themselves highlight the most critical aspects of an organization’s impact on the environment and provide a platform for focusing actions and for educating the workforce to improve their contribution to best-practice operations. This paper discusses the benefits and challenges of undertaking an EFA for a mining company, and provides examples of the various components of ecological footprints associated with mines, as well as showing how an EFA can be used to understand and communicate some of the impacts associated with mining activities.IntroductionFundamental biophysical and economic limits are now being experienced in many countries around the world. Herman Daly, a former World Bank economist, described this scenario as ‘uneconomic growth’, where the costs of growth exceed the benefits (Daly, 2005). This occurs when the economy’s expansion encroaches excessively on the surrounding ecosystem, sacrificing natural capital. Under such conditions the sacrificed natural capital is more valuable that the resulting economic growth. Consequently, the world faces largescale threats to sustainability and especially to the viability and continued existence of the ecosystems that support human settlements (El Zein et al., 2014). In recognition of this sustainability imperative, mining companies are increasingly concerned with their ecological footprint (EF)."

Jan 1, 2017

By P. A. J. Cabassi, B. K. Loveday, M. J. Wilkinson, P. H. Radcliffe

The recovery of gold, uranium, and pyrite from accumulated residues at mines in the Orange Free State is adversely affected by the presence of pyrophyllite, which is naturally floatable and must be prevented from floating with the desired constituents by the use of a mica depressant, and of thucholite (uraniferous kerogen), which contains significant quantities of uranium and gold but does not float readily in the presence of a mica depressant. In laboratory tests on these residues, the use of a mixture of MIBC (methyl isobutyl carbinol) and paraffin in addition to the suite of reagents normally used was found to increase the gold recovery substantially, but the sulphur grade was lower. The recovery of thucholite also increased considerably, but the proportion of uranium associated with this mineral was small. Plant trials, which are continuing, have been encouraging, indicating an increase in the gold recovery of 4,6 per cent.

Jan 1, 1983

By J. M. Stewart

Although the incidence of heat stroke in South African gold mines is small, work continues on its reduction. This paper proposes limits of heat stress that are applicable to South African underground conditions, with the warning that they should not be extrapolated to other situations without careful consideration having first been given to their limitations. These limits of heat stress take physical and physiological considerations into account, and they correspond to there being a 10-6 risk of an essentially nude man developing a rectal temperature in excess of 40°C. It is recommended that further work should be undertaken on the development of equations for the calculation of the heat transfer from clothed men, the derivation of equations that quantify the physiological conductance and sweat rate response of humans, and on establishing the frequency distributions that describe variations in rectal temperature response between individuals in different types of environment.

Jan 1, 1981

By D. D. Howat

The first joint colloquium between the South African Institute of Mining and Metallurgy and the South African Branch of the Institution of Metallurgists was held in Kelvin House on 23rd April, 1981. About eighty delegates registered, the majority being associated with the local branch of the Institution of Metallurgists. Types of Abrasion and Wear Professor A. Ball, of the University of Cape Town, gave the opening address, which he entitled 'Some Thoughts on Abrasion and Wear'. In his thoughtprovoking talk, he quoted some figures showing that, in the highly industrialized countries, loss by wear and abrasion might amount to about 4 per cent of the gross national product but, in the Republic of South Africa, it was believed to be about 6 per cent of the gross national productprobably associated with the massive influence of mining in our economy. Professor Ball described wear as being of three main types.

Jan 1, 1981

By M. Kirsten, W. H. Botha, M. H. Fox, J. A. Moolman, A. J. Lathwood

Water is a valuable and in many areas a scarce resource. Governmental legislation regulates the environmental impact of water usage and wastewater disposal through the issue of licenses. These requirements mean that hydrometallurgical refineries must ensure that water consumption and water disposal is managed on a continuous basis in order to prevent the repeal of their operating license. Water balances are often overlooked during the design of a hydrometallurgical refinery. Recent changes in environmental legislation have forced both design engineers and operational management to review water use and disposal within these processes. Unlike concentrators where water can easily be recovered by recycling from tailing dams, water introduced into hydrometallurgical refineries becomes contaminated with soluble metals and thus requires pre-treatment prior to disposal. This paper discusses the various concerns that need to be considered during design and operation of hydrometallurgical refineries with respect to the water balance.

Jan 1, 2007

The optimization of sample spacing In South African gold mines by J. M. RENDU*, Eng. Se.D., M.S. (Min.) U.S.A. (Graduate Member) A first attempt is made at optimization of sample spacing in South African gold mines. The De Wijs model, which is shown to give a good representation of the geostatistical properties of gold values, is used to analyse the influence of the distance between samples along a stope face on the error of estimation of the stope value. The influence of other factors such as the face advance before resampling, the sample density, and the stope size, is also considered. Practical conclusions are drawn concerning the optimum sampling policy to be followed in various situations, and it is shown that sampling on a regular grid does not necessarily give the best results.

Jan 4, 1976

The 97th Annual General Meeting of the The South African Institute of Mining and Metallurgy was held in the Gold Room, Transvaal Automobile Club, 60 5th Street, Lower Houghton, Johannesburg on Wednesday, 10th August, 1994. Obituaries The President announced the passing during the year of the following members:

Jan 1, 1994

By O. Y. Ntrama

Lebowa Platinum Mines has been in operation since the late 1960s and is a relatively small producer compared to Anglo Platinum?s other operations. The mine has never had substantial capital investment to expand its production scale even though its resource base is estimated in excess of 100 years at current mining rates. It is forecast that the mine will become unprofitable after 2008 due to the workings of the ageing infrastructure, the Merensky Reef operations being further from the shafts, decrease in productivity and increase in operating costs. In order to reverse the forecast decline in operational inefficiencies and profitability the replacement of the Merensky Reef operations at Vertical and UM2 shafts with the development of a 120 Ktpm Brakfontein Merensky Reef Mines is in progress. This paper covers the operational readiness framework developed from the control budget estimate and outlines an integrated business process adopted to ensure that the requirements of the investment proposal are met. The operational readiness framework, which addresses the transition process, will ensure that at operational start-up, all appropriate operating systems, procedures, information and legal requirements are in place, whereas the business integration process will aim to develop and sustain an organization with the appropriate infrastructure and workforce equipped with the necessary skills to meet Brakfontein?s requirement, and where possible embark on an optimized accelerated production initiative to ensure that the objectives of the investment proposal are sustained. Keywords: operational readiness, business integration, optimized accelerated production initiative, organizational development.

Jan 1, 2006

Book Review Sampling in the mineral and metallurgical processing industries. London, Institution of Mining and Metallurgy, 1973. 65 pp. illus. £5. The seven papers presented at a special meeting of the Institution of Mining and Metallurgy held in London in July, 1973, have been brought together under the above title.

Jan 11, 1973

By L. M. Falcon

Cassiterite is considered to be the only economically significant tin mineral in the earth's crust. In its purest form, cassiterite contains 76 per cent tin. The mineral is hard and heavy but also extremely brittle. and is therefore ideally suited to gravity recovery techniques. Cassiterite deposits can be categorized into two main types, i.e. alluvial or 'soft' rock deposits, and 'hard' rock deposits. The former are relatively simple to upgrade owing to their relatively coarse nature and their high degree of liberation. Hard-rock deposits, on the other hand, require considerably more sophisticated gravity methods to achieve the required degree of beneficiation. Various types of gravity recovery devices, both old and new, are described, and their respective roles in the flowsheets used are illustrated.

Jan 1, 1982

By R. A. Plumbridge

I am deeply honoured by your invitation to address your great Institute on this centenary occasion. Mining is a cyclic industry that continuously faces enormous challenges as it wrests the treasures of the earth from an often reluctant mother nature. Throughout the ages, those challenges have demanded great skill from mining men and women, who are required to blend a mixture of robust determination with art and science. Pioneer Miners and Scientists It is not surprising therefore that the first blush of euphoria surrounding the discovery of gold on the Witwatersrand quickly gave way to consternation about the need to increase the metallurgical recovery of gold from the then readily identifiable conglomerate. The rugged pioneer miners had to turn to scientists for their salvation.

Jan 1, 1994

The relationships between backfill-transportation parameters (solids concentration, velocity, and pipe diameter) and the wear rate of backfill-transportation pipelines is well understood. However, the degree of wear experienced by a pipeline depends not only on the transportation parameters, but also on the characteristics of the solids making up the backfill, i.e. the particle-size distribution, hardness, shape, and sharpness of the particles. Therefore, unless data corresponding to the specific wear rate of the solids are available, the determination of the wear rate for pipes transporting an uncharacterized backfill is largely guesswork. This paper describes an evaluation of particle characteristics with special reference to particle sharpness so that pipe wear rates can be correlated with solids of different size distributions and sharpnesses.

Jan 1, 1993

By J. J. Geldenhuys

Premier of the North-West Province, Mr Molefe, foreign dignitaries and guests, ladies and gentlemen. It is a pleasure and also a special honour for me to have been invited here this morning to make this address. The xv Congress of the Council of Mining and Metallurgical Institutions is, by its very nature, an extremely important event for the international minerals industry. But I believe that this specific Congress assumes an even greater significance because of the profound and far-reaching changes that have taken place in South Africa this year. These are exhilarating times, a period when so much in our country has altered and when so much has to be done so quickly to build positively on our bold political decisions.

Jan 1, 1994

By B. M. Kunar

It is well known that job-related hazards and individual factors influence occupational injuries. However, research involving coalminers has been limited. This case-control study assessed the relationships of job-related hazards and individual/life style factors with injuries among underground coal miners. It compared 245 cases with at least one injury during the previous two-year period with 245 matched controls with no injury. The data were gathered via personal interview and analysed using the conditional logistic model. The significant risk factors were materials handling (adjusted OR 5.15), poor environmental/working conditions (2.63), geological/strata control-related hazards (2.35), lack of formal education (3.00), sleep disorders (1.86), alcohol consumption (2.32), disease (2.23), having a large family (5.40), and risk-taking behaviour (9.40). Machine-related hazards, sleep disorders and alcohol consumption primarily affected workers aged less than 45 years; whereas, environment/working condition-related hazards, presence of disease, smoking, risk-taking behaviour and large family size were more likely among workers aged 45 or over. Keywords: Occupational injuries, sleep disorders, job hazards, alcohol, coal miners

Jan 1, 2010

Brigadier R. S. G. Stokes of Sherborne, Dorset, is the oldest surviving member of the South African Institute of Mining and Metallurgy. He joined in 1904 and has been a member for 77 years. Book review Sittig, M. Hand book of catalyst manufacture. Park Ridge (U.S.A.), Noyes Data Corporation, 1978. The detailed information in this book is based on patents issued in the U.S.A. that deal with catalysts and their commercial technology. Project management The South African Institute of Mining and Metallurgy is to hold a Colloquium on Project Management in the Metallurgical Industry in March 1980. Ingenieurs-in-opleiding in die weermag Op 'n onlangse vergadering van die Suid-Afrikaanse Raad vir Professionele Ingenieurs is daar besluit om kwytskelding van jaargeld aan geregistreerde ingenieursin- opleiding wat tans met hulle tweejaar nasionale diensplig besig is, te verleen met dien verstande dat.... Engineers-in-training in the army At a recent meeting of the South African Council for Professional Engineers it was resolved that a remission of annual fees would be granted to registered engineers in- training who are doing compulsory two-year national service, provided that.... Processing of fine particles The Society of Mining Engineers of AIME is organizing an International Symposium on Fine Particles Processing, which is to be held in Las Vegas from 24th to 28th February, 1980. Economics of precious metals International Precious Metals Institute announces a Special Course for all interested in economic aspects of today's precious metals.

Jan 1, 1979

By A E. Paterson

General aluminium corrosion charts based on 1100 alloy listing product and temperature have been developed by AFSA, mainly from available sources. The categories of corrosion expectation are fairly wide. As a result the charts are more useful in indicating what is not suited as distinct from what is. The question of how to develop useful information is assessed. Having discarded improbable options one is left with the need to refine the possible. Within each alloy group corrosion potential differs. From an engineering application point of view, the corrosion resisting marine alloys, the 5xxx series show increasing corrosion as the percentage of Magnesium increases. An important issue is that as the welding filler used for 5xxx series is Mg rich (to avoid hot cracking), the filler is likely to show the weakest resistance. In addition, when subjected to fatigue loading, the preference for critical joints is to dress the joint to the level of the base material. Overheating of the weld extends the HAZ zone and weakens the material as Mg moves to the grain boundaries. Indicator chart refinement approaches suited to aluminium use in commercial transport are discussed.

Jan 1, 2006

By Colin M. Spence

The Federation of Societies of Professional Engineers (FSPE), in collaboration with the Habitat Council and the Environmental Planning Professions Interdisciplinary Committee (EPPIC), held a Symposium on 'Engineering our Environment' at the Rand Afrikaans University on 5th June, 1984, under the chairmanship of Mr Colin M. Spence, Vice-President, to commemorate World Environment Day.

Jan 1, 1984

By D. Borman

The location of underground positions in mines has usually fallen to their survey department's. Their usual tasks include: ? installation of a high-precision peg network like the National Survey grid as beacons ? offset measurements to the sidewalls, and sometimes hangingwall and footwalls, of development tunnels and excavations ? offsetting of stoping panels for the calculation of face ? advance and the square meterage of area removed. Other departments build their observations into the plans produced by the surveyors. If more precision is required, they ask the surveyors to `elevate' their points with a theodolite. Apart from the survey peg network and `elevations' these measurements are usually planer measurements suitable for producing plans, sections and projection sheets. When the only representation medium was a sheet of paper or transparency, this was perfectly suitable. However the development of CAD models of the workings has changed all this. Full 3D representation is not properly catered for in the tool sets in current use, and needless hours are spent converting analogue-type observations into digital form. The basic survey models need to be augmented by the observations of other disciplines that are also required to locate positions underground. These include: ? the need for geologists to plott their mapping and ? borehole logs into 3D space ? the need for samplers to position their sample points accurately because the geostatistical models are biased and inaccurate ? the need for stoping width recorders to position their thickness observations to prevent errant evaluation and bonuses ? the need for rock engineers to place their mappings into 3D to build true geotechnical models to manage geotechnical stresses ? the need for production officials to receive updated face ? positions during the month so that they can manage the ? production and utilize their resources properly. This paper covers a new method of positioning profiling points to a suitable degree of accuracy. I believe the method is sufficiently simple and cheap for all to use. Historical methods Platinum and gold orebodies, especially in South Africa, are generally narrow tabular deposits. This made them suitable for depicting on a 2D medium like paper. The determination of stoping or face widths was not a problem, as the ore is removed in a single stoping process. Such 2D representations could be easily positioned using tape offsetting between survey pegs or points tied in from survey pegs. Problems of dip were handled by using 'Stope Sheets' which chose a best fit projection for the whole area depicted or by using true dip section sheets for inclined tunnels. Rolling reef and potholes were the common areas of difficulty. Most mines now model their orebody and plan the extraction in computer graphics. This means that the representation of the current workings has to change to support this trend. It now becomes a truly 3D problem. Mining officials find it inconvenient to have their actual workings in single-line depictions while their orebody is depicted with top and bottom contacts and the planned tunnels in 3D shapes. Geological models which form the basis for the resource model and planning process are often out of date, as the updating process is slow. The geological mapping has to be plotted onto sections and plans. These are then digitized into graphics by a draughtsman and checked by the geologist. Only then does the interpretation and model update take place. Potential methods to create 3D 'Actuals' Global positioning systems (GPS) Surface mines have been blessed by the advent of GPS technology. These simple-to-operate pieces of equipment and compatible software make it possible for all types of mine employees to locate themselves, and therefore to locate their observations. GPS are often inexpensive and give an acceptable degree of accuracy. Only in deep pits or close to the highwalls are observations hindered. Such technology cannot however, work underground. Ground penetrating radar (GPR) GPR is reported to be very useful for estimating the positions of potholes and faults. However it is still considered as providing an estimate, not a definite measurement. GPR is good for seeing into solid rock, not into open spaces. Inertia reading devices Experiments with inertia reading devices have been conducted on the mines. They were the forerunners of GPS for military guidance systems, and were even used for city navigation in the early 70s. They do however work best with heavy or fast-spinning gyros. Anglogold Ashanti's attempt to use them were discontinued in the mid-90s when the developers asked for an additional few million rand for a device that would weigh more than 12 kg and have a limited operational life.

Jan 1, 2006