Search Documents

By Nyamekye GA, Subramanian S

Adsorption tests have been carried out to elucidate the interaction mechanism between dextrin and sulphide minerals. Sulphides such as galena and heazlewoodite exhibit high affinity adsorption over the pH range that coincides with the iep of lead and nickel hydroxides, and is suggestive of chemical interaction. The adsorption behaviour with respect to the sulphides of copper is of the low affinity type, and follows a different pattern. The adsorption studies on graphite, support the chemical interaction mechanism, with the metallic impurities serving as adsorption centres. In conformity with the proposed mechanism selective separation of galena from chalcopyrite and heazlewoodite from chalcocite has been Achieved.

Jan 1, 1993

By R G. Barker, A B. Christie

Minerals are necessary for providing almost everything we take for granted in our daily lives including food, shelter, and supplies of energy and water. Minerals are therefore essential for the maintenance and improvement of the standard of living of all New Zealanders.

Jan 1, 1998

By R J. Everett

The mining industry is beginning to adopt quality systems based on the requirements of International Standards for quality assurance, such as the ISO 9000 series. Indications from similar industries are that considerable benefits are to be had from their adoption. This paper describes the use of the International Standard ISO 9001 for quality assurance within BUKA Minerals Limited. This provided guidance for the development of a clear statement providing agreement on the processes to be followed and the outputs required when dealing with outside service providers. Discussion focuses on the interaction with BUKAÆs consultants and contractors during the specification stage, resulting from the application of quality assurance techniques. Risk analysis was used to identify and manage the risks associated with the companyÆs contract for geotechnical and mine design services and the tender for a mine development program of work during the feasibility stage of the project. Setting acceptance controls for the deliverables from such contracts is traditionally fraught with difficulty. BUKA used Failure Mode and Effect Analysis for exposing underlying risks that were not effectively being countered. The briefs were reviewed and additional controls were developed to manage the risk. These controls have provided clearer instructions to the consultants and contractors, indicated audit points for the company and defined the deliverables. There exists within the company, and among its outside service providers, a clearer understanding of what is to be achieved and how it will be measured. The process has imparted considerable confidence to both parties on how the work will proceed and what outputs are to be provided. Some discussion is provided on how quality principles are being applied throughout industry and commerce, generally, and how they may apply to the mining industry. The paper argues that, far from being an appendix to the tendering process, Risk Management should be a mandatory step integrated into the definitions of the work.

Jan 1, 1998

By Koppe J. C, Dimitrakopoulos R, Costa J. F

Grade control and the delineation of ore/waste in open pit operations is traditionally based on the comparison of estimated grades with an economic cut-off. This paper deals with an alternative approach to grade control based on estimating gra

Jan 1, 1998

My early experience with the coal industry was in the latter half of the 1970s, where attention to only ones own æaccidentsÆ and concentration on behaviour controls were impeding the introduction of effective engineering controls such as ROPS, FOPS, roof support and residual current devices. Lack of the broad picture of personal damage and of relevant veridical (true saying) knowledge and data had to be overcome to achieve progress in reducing fatalities. Thirty years on, it is again necessary to take stock. How good is our knowledge, our data, our information on which we make decisions. Despite Australian all industry 1992-93 data showing 80.5 per cent of costs came from occurrences which permanently altered peopleÆs lives, New South Wales is still the only state reporting permanent disabilities. In 1991 - 1992, the rate of permanent disability per 1000 wage and salary earners was two. In 2000 - 2001, it was over four û more than doubled. Also strongly motivating is the huge cost. Industry carried 25 per cent of the $34.3 billion costs for 2000 - 2001, up ten per cent of 82.8 billion if the costs of pain, suffering and early death are included.

Jan 1, 2005

The issue of fine coal and tailings dewatering has become of increasing concern to many coal preparation operators, both in Australia and overseas due to a variety of factors. Increasing mechanisation and mining of thinner seams over the past decades has resulted in an increasing amount of fines generation while increasing international trade in coal and tighter environmental constraints on tailings disposal have resulted in the production of these same fines to be an increasing problem. However, technology to date has not always been able to supply a cost-effective solution to the handling of these fines in an efficient and environmentally benign manner. This paper will review the key issues associated with the dewatering of fine coal and tailings, will describe the major current practices and constraints, and finally will indicate alternative technologies that may have to be considered in the near future. For the purpose of this paper, "fine" coal is described as that material less than 0.5 mm in diameter (as this is the most common cutpoint between various plant circuits in Australian practice), although the technological constraints are very much dependent upon the fraction less than 45 micron. The amount of minus 0.5 mm material fed to plants varies, depending upon the type of coal and mining operation, but in Australia may range from less than ten per cent to greater than 30 per cent of the feed in higher rank coals.

Jan 1, 1991

During the last century Allis-Chalmers has supplied many screens of various types to industry, from revolving screens to the large capacity highly efficient screen available today. The features incorporated over these years in horizontal and inclined screens are varied and numerous and include many innovations such as tri-and bi-sloped screen decks. Today the emphasis is on wide vibrating screens with good "G" value, with large "throw", to achieve high capacity. Larger screens lead the way to treating a somewhat neglected area of mining operations - that of concentrator mine flotation tailings to allow effective transportation and stacking by conveyor belt. The benefits from a cost, water saving and environment view point are discussed in this paper.

Jan 1, 1984

By Yoon R-H, Luttrell GH

A theoretical model has been developed to predict the probability of particle collection by air bubbles in a quiescent flotation pulp. The model considers the effects of both hydrodynamic and surface chemistry forces acting during the bubble-particle interaction. Hydrodynamic forces considered include the gravitational, buoyancy, streamline and film thinning resistance forces. The surface chemistry forces considered include the electrostatic, dispersion and hydrophobic forces. The hydrophobic force has been estimated from extended DLVO theory. The model is capable of predicting hydrodynamic and surface chemistry conditions under which bubble-particle adhesion is possible. Validity of the model has been verified experimentally.

Jan 1, 1993

The search for an efficient and economic machine to excavate hard rock continues. Development of the Robbins Mobile Miner commenced in 1983 with the formation of a joint venture between Mount Isa Mines Limited and The Robbins Company. Construction of the machine ensued and preliminary trials to verify the cutting action were undertaken in the USA prior to transportation to and assembly at Mount I-sa where mining commenced in September 1984. Initially, the machine was used to develop the S60 Decline which serves as a combined access and conveyor drive for the Southern 1100 Orebody Ore Handling System.

Jan 1, 1988

A good blending system is one that ensures that a plant can cope with the amount of grade variation that it will encounter. Prediction of amounts of variation that will be encountered on time or tonnage scales that are important should be regarded as an essential part of the planning of mines and plants. In some cases, the natural amount of grade variation when ore is mined and handled in the cheapest way will be acceptable. In other cases, it is necessary to understand the effects that various ore-handling processes have on amounts of grade variation at various scales and to design a blending system with considerable care. Blending tends to matter more when plants are sensitive to many aspects of grade. It can be very difficult to find the best compromise between capital cost and the amount of grade variation. In these cases it is important that ore blending options be considered carefully as part of the planning of mines and plants. Failure to make plans that consider likely amounts of variation can be very expensive.

Mar 1, 2010

By Longtin Z, Jin C, Zixin C

This paper proposes a new idea of disintegrating mode (division into simpler sub-problems) for complex problems, and based on -it, a study of the structure and the design of a knowledge base and inference engine for layout design of mineral concentrator expert systems. There is also a study of the formalisation method for describing the layout picture, and the work derived therefore found a formalisation method for expressing the knowledge and experience of layout design. There is also a study of the general characteristics of layout design knowledge.

Jan 1, 1993

Selective continuous surface mining is a rapidly developing system of mining which will have a significant impact on many present and future open cut mines. In many aspects the technology is in its infancy, whilst in other facets concepts drawn from other sectors of engineering are well proven. Full development of the potential and benefits of this technology will only be achieved if the mining companies and manufacturing companies work together to produce machines which the end user really wants.

Jan 1, 1986

By De Janti VP

The automation and centralized monitoring of longwall type underground mining is presently an important subject matter of research in France. The purposes are :to improve safety and working conditions to increase productivity.to improve efficiency in machine operation through continuous "health monitoring". to make winning possible in difficult seams.

Jan 1, 1985

By Darby H. P, Vincent R. J

Sydney's Eastern Suburbs Railway from Central to Bondi Junction required the construc- tion of 10.4 km of single-track tunnel and five underground stations. Much of this work took place beneath the commercial centre of Australia's largest city. This paper discusses the general precautions taken and the specific design solutions made for such problems as support of a 15-storey building with foundations several metres above the excavation to ensure negligible differential settlement, excavation immediately below running tunnels, underpinning of multi-storey buildings, tunnelling under massive masonry retaining walls and demolition and rebuilding of part-completed structures.

Jan 1, 1981

A portable surface impedance meter has been tested extensively over a wide variety of geological formations both in Australia and elsewhere. It has proved a useful geophysical too] for relatively shallow mapping (i.e less than 100 metres depth) of faults, intrusions, dykes and conductive ore veins and can be used as a depth probe for overburden and glacial ice. Case studies involving coal seam mapping at Collide (Qld. Australia), galena ore vein location at Zeehan (Tas. Australia) and glacial ice probing on the Brewster Glacier (South Island, New Zealand) are detailed. The first results of a similar unit using a lower frequency with consequential increase in depth of penetration will be presented. The application of VLF measurements to monitor blasting in mines and in the location of earthquake epicentres will also he introduced.

Jan 1, 1987

By Colquhoun L

Flooding velocities were measured in a laboratory column (96 mm 4) provided with both bottom and side air entry Packings used were 6 mm glass rings and spheres and -16 +8 mm coke. Results showed that when air was introduced through side nozzles flooding velocities were much higher than those obtained when air was introduced at the bottom of the column. Significance of the results and application to blast furnace flooding is discussed from the viewpoint of assymmetric gas flow.

Jan 1, 1975

Synthetic hollow microspheres have demonstrated reliable sensitization and detonation characteristics in industrial explosives for almost two decades. During that time, water gel formulations and use conditions have changed. The introduction of emulsion explosives has also dictated technical improvements in microsphere sensitizers. In contrast to microspheres, gassing or other sensitizing techniques often cannot satisfy the manufacturing and blasting characteristics required of today's explosives. This paper discusses the sensitizing properties of microspheres, formulating guidelines and quality considerations. Packaging, sampling, transfer, metering, mixing and pumping information is also provided.

Jan 1, 1990

The Pacific Rim and its environment involves a vast array of natural phenomena, and a vast array of situations which show the impact of man. Almost half the world's population of over five billion live in nations" which border the Pacific, but the concentration is focussed in the North. Great experiments are occurring in this region, the industrialization and energy development in- Japan and China, the growth of Indonesia, (now 168 million - soon 368 million; Brown and Jacobson, 1986), the enormous developments of agriculture and the metals resource base in Australia and China. At the same time, the Pacific Rim does not project images of hopelessness, the mood is upbeat. Over the past decade, incomes have increased substantially in most of the major countries of Pacific Rim (e.g. over the period 1980-86, + 58% in China, + 21% in Japan, + 34% in South Korea; Brown and Jacobson, 1986). In September, 1986, at the general assembly of the International Council of Scientific Unions (ICSU) in Bern, Switzerland, representatives of over 50 nations approved a new initiative, "The International Geosphere Biosphere Programme: A Study of Global Change". The focus of this new program is "To describe and understand the interactive physical , chemical , and biological processes that regulate the total Earth system, the unique environment that it provides for life, the changes that are occurring in this system, and the manner in which they are influenced by man. The IGBP will be a tightly-defined programme of research, directed at providing fundamental knowledge that will serve as a basis for assessing likely future changes on the Earth in the next 100 years" (ICSU, 1986). For the earth scientist, and all resource scientists, there is an emerging agenda; new priorities are appearing, new questions are being asked. The recent report of the World Resources Institute (1986) focusses on this emerging agenda. Topics which are at centre stage in this report include the following: The environment and human health Tropical deforestation The atmosphere as a shared resource and climates Soil-degradation Rural-urban migrations Food and agriculture The diversity of species-ecosystems Freshwater as a finite resource Coastal areas and resources

Jan 1, 1987

Clearly visible in geophysics is a trend away from simply finding and drilling anomalies obtained with off-the-shelf equipment, condes- cendingly sold by travelling salesmen. Instead, technical tools are becoming available which allow us to choose or design equipment and sur- vey procedures for the specific problem at hand. The advent of micro- and smaller computers enable us to collect more and better measure- ments and to rapidly process them so as to emphasize the features which are being sought. These new capabilities have important consequ- ences both to the extent to which geophysical tools will be applied in the industry, and to the skills which will be demanded of those using them. Because of its uniquely difficult exploration problems, Australia must expect to amplify its new prominence in the development of mining geophysical technology.

Jan 1, 1981

DIVERSITY There are plenty of examples to show that diversity has been the fundamental downfall of many organisations, particularly when you consider the international position. What about core business, the return of companies to key competence directions and market focus. The stockmarket for instance defines groups and companies in key groups of core business. The expectation is that companies toe the line and do not diversify across their areas of defined expertise. In essence, the market has given notice that the requirements are to focus and stick to our core business. So what right does the conference have to suggest that diversity is the key to prosperity. Hasn't the organiser read the book, studied the history, listened to the market - obviously not. Have they got it wrong, My feeling and belief is no - the organisers have got it right. However, the matter is not as simple as first perceived. What is Diversity, or Diversification as I would prefer? Is it a product position? Is it a geographic position? Is it an expansion or change in services offered? Does a gold mining company diversify into copper or diamonds or aluminium or nickel? Does a gold miner in Australia diversify into China or Kazakhstan or West Africa? How do the two relate? They don't. A successful company will always possess a 'core competence' not so much a 'core business'. The best example of this is the service company extraordinaire - McDonalds. They don't sell hamburgers or french fries, they sell a service, a convenience, a lifestyle. The core business is hamburgers and if McDonalds were to diversify further into new styles of hamburgers, I suggest to you they would fail. But if McDonalds were to diversify into other products based on their 'core competence', provision of service, then I would suggest to you they would be very successful. The service procedure, service machine, service system, the formula, stava the rnnetant the nrnrlnrte -

Jan 1, 1996