Search Documents

A three-dimensional finite element analysis is used to determine the stress intensity factors associated with the chevron-notched semi-circular bend test specimen. The stress intensity factor calibration is done over a range of crack lengths a

Jan 1, 1998

By Wernick B. J

Recently, the Environmental Engineering Laboratory of the Chamber of Mines of South Africa Research Organization has made signifi- cant progress in the development of more accurate algorithms for assessing heat flow in gold mines. These algorithms have been incor- porated into an overall computer program, ENVIRON, which enables the complete thermo- dynamic analyses of mine ventilation and cool- ing systems to be carried out. Recently, efforts have concentrated on the development of an expert computer system which will guide engineers in the process of selecting the most appropriate environmental control strategy.

Jan 1, 1988

By J S. Simmons, J G. Skousen

This project evaluated the performance of nine passive treatment methods by studying 137 treatment units in eight eastern states. Performance was normalised according to construction cost, projected service life and kilograms of acid load treated. Results were dimensioned as $/kg of acid load treated/year. These costs were then compared to those of chemical treatment. Sites that achieved acid load reductions at costs below those of chemical treatment were considered successful. In addition to evaluating the performance of the treatment methods, this paper describes the various passive treatment systems, their applications and performance data for individual treatment units.

Jan 1, 2003

Members of The Australasian Institute of Mining and Metallurgy are engaged in locating, extracting, processing, marketing and converting the worldÆs mineral wealth for its consumption in a useful form. We have an ethical responsibility as professionals to carry out our roles in such a way that we seek to optimise the recovery of that wealth for the benefit of the community, not only now, but also in the future. To be able to optimise, we must be able to measure with confidence the value of the commodity through the various stages of treatment from discovery of a geological anomaly to the end use. This introductory paper will provide an overview of some aspects of the issue, including the possible extension of the coverage of The InstituteÆs Codes to production accounting and reporting.

Jan 1, 2002

The treatment of steels with acid solutions for the removal of oxide products represents possibly the largest outlet for chemicals in steel processing. Organic pickling inhibitors are required to prevent base metal attack by these acids otherwis

Jan 1, 1980

An experimental study of the influence of surface active agents on the dewatering of fine coal was undertaken with a view to evaluating the usefulness of such materials in reducing the residual moisture contents of filter cakes. Experimental evidence is presented which suggests that while polymeric fiocculants have a beneficial effect on settling, they can have adverse effects on the filtration of the thickened underflow. Detergent addition, on the other hand, was shown to reduce filter cake moisture, and the magnitude of this effect was determined, in part, by the prevailing electrochemical equilibrium at the solid-solution interface.

Jan 1, 1976

Peraluminous metamorphic rocks may form from a variety of protoliths by a range of processes. Stratiform bodies of such rocks are relatively common in the Precambrian, but less commonly, also occur in the Phanerozoic. The protoliths of such stratiform bodies may have been regionally deposited chamosite-rich sediments, with varying amounts of clastic component, or may have resulted from the in-situ depositional or diagenetic alteration of volcaniclastic sediments, ranging in composition from rhyolite to basaltic andesite.Stratiform peraluminous metasediments, especially those of low to medium metamorphic grade, and relatively iron rich, may be genetically associated with, or be the host rocks for, a variety of styles of mineralization, especially for the ores of An, Ag, Cu, Zn and Pb.

Jan 1, 1990

By Hare G

The emphasis in Australia, until recently, has been on large scale mining methods with drive sizes in excess of 4.5 metres square and the acceptance of high dilution ratios, even when working in relatively narrow orebodies. The rising cost of extracting and treating the recovered ore and the lower prices available in the world markets has seen a growing trend to narrow mining methods.Traditionally narrow orebody mining has been carried out using hand held drilling methods and rail mounted boggers. Recent advances in mobile equipment now offers the operator of narrow method mines the opportunity to completely mechanise the mine from the drilling, through bogging to haulage, while maintaining minimal dilution in drive sizes to two metres wide or less.

Jan 1, 1993

The difficulty of successfully imple menting a landscape policy is almost incom- prehensible. Landscape design is recognised as an essential component in the integration of engineering and architectural projects into the landscape, but the factors which prevent the achievement of a successful result are rarely recognised or assessed. In many cases these prohibiting factors are due to a lack of understanding of the effect of major planning decisions on the existing landscape, the importance of the landscape plan and the significance of appro- priate specified techniques to prevent un- necessary damage and to ensure retention of existing vegetation in a healthy condition. The role of the landscape architect in incorporating new land uses into the landscape provides the background against which factors which inhibit policy achievement can be con- sidered.

Jan 1, 1976

By Walton DR

It is self-evident that the availability of well qualified and experienced people to manage mining operations is vital to the success of an individual mine and to the ability to develop new mines either in Australia or overseas. For larger operations the term "mine manager" is here used to denote a range of positions within an individual company. Thus "mine managers" may be people managing individual mines at one geographic location with overall management provided by other "mine managers" in the roles such as mine super- intendents, production managers, general managers, etc. Smaller operations may have only a single level of management nominated as "mine manager".

Jan 1, 1980

The short review of hydrogeologic conditions in the three Polish coal basins have been presented as the background for the prevention measures against water inrushes being underta- ken in coal mines. The Polish mine safety regulations concerning water inrush prevention have been discussed, namely: - classification of sources of the potential water inrushes, - levels of water inrush risk and conditions of mining operation in the mines facing particular risk levels, - determination of the -di.mens.ons.of protecting pillars to prevent water inrush to mines, protection of surface water reservoirs and their earth embankments in regions submitted to mining deformations. Three examples of coal mining being carried out under water bodies have been presented.

Jan 1, 1988

Economic evaluations of mineral projects are based on discounted cash flow analyses, followed by sensitivity and risk analyses. However, the global macroeconomic and political environment in which the mineral industries operate have a profound effect on the viability of individual projects. Since the oil crises of 1974 and 1980, demand patterns for minerals have become much more variable and prices more volatile. Significant changes in the geographical distribution of world mineral supply and demand are underway, and the mix of minerals used is also changing. Social and political factors are as important as economic and technical factors in determining the viability of mineral ventures. Economic evaluation of mineral projects have to be undertaken in a more uncertain and risky environment. They can no longer be reduced to a number crunching exercise.

Jan 1, 1987

By Harris HR

This paper documents the selection, installation and performance of six, seventeen cubic metre, Dorr-Oliver flotation cells for primary zinc flotation at the North Mine in Broken Hill. The cells were installed to replace fifty, small cells, and despite initial design problems, have per- formed satisfactorily.

Jan 1, 1988

Green policies have gained momentum since the 1972 Stockholm Environment Conference. The environmental movement has influenced political initiatives both in New Zealand and abroad. Governments and international institutions have addressed local, regional and global environmental issues with varying degrees of success. New Zealand so far has not supported the United Nations' call for sustainable development in a,consistent manner.New institutions and new rules for resource management mean there are opportunities to look after the land in different and more ecologically sensitive ways than has happened in the past.The increasing influence of regional councils in resource management planning will have important implications for mining and mineral exploration. These trends are discussed and possible future events outlined.

Jan 1, 1990

In considering the architectural design of the group of buildings which make the surface workings of a mine, the variety of function of the buildings is the most outstanding feature. It falls to the architect to unify the group in a manner which still expresses the function of the individual buildings. In achieving this, many perspective studies were made at an early stage and as the area was developed, a scale model was produced initially for design study purposes and later completed as a model of the final development.

Jan 1, 1957

With the continuing move towards digital signal based control and measurement, it is inevitable that such technology will be increasingly employed on remote sites. The benefits of increased metallurgical performance, of reduced energy and manpower requirements far outweigh the problems associated with high technology in remote locations, provided that the installation is well thought out from both technical and manpower viewpoints. The new accessibility of vast quantities of process data will uncover previously unthought of savings and profit opportunities but brings with it the responsibility to carefully design the data presentation methods. The resulting changes in installed hardware will force changes in the maintenance and engineering workforce and will affect even the stores and purchasing department methods.

Jan 1, 1985

By Belcher C. B

A simple gravimetric procedure was developed for the rapid determination of carbon dioxide in coal mine roadway dust samples and the result is used for the subsequent calculation of incombustible matter contentaccording to the requirements of the Queensland Coal Mining Act. The carbon dioxide is determined through loss of mass by a semi-enclosed apparatus, following room-temper.ature hydrochloric acid attack on the sample.With a sample containing 36 per cent carbon dioxide, the achieved standard deviation (ls) of 0·3 per cent CO. is adequate for coal mine roadway dust analysis.This simple procedure enables relatively unskilled labour in mine laboratories, to analyze coal mine roadway dust samples in accordance with the Act. Some 50 analyses can be achieved per day compared with 8 by the Australian Standard Method for coal.

Jan 1, 1976

By Noble AC

Ore reserve reporting practices in the United States may be broken into four general categories as follows: ò Reserve reports, often of an unofficial and preliminary nature, which are made through the news media. These are often based on exploratory drilling or sampling results. ò Reserve reports made for the purpose of raising public funds by issuing securities on the stock market, or as part of other filings to the United States Securities and Exchange Commission. ò Reserve reports to obtain private funds from banks, financial institutions, or other investors. ò Reserve reports for internal use and planning by companies operating or evaluating mineral properties. This paper discusses current practices for each of these types of ore reserves reports and reviews recent changes which have affected those practices.

Jan 1, 1987

By Shiels O. J

The paper reviews developments in general galvanising in Australia, including a brief history of the industry and its technology. The changes in galvanising process technology are covered, as well as developments in galvanising bath design, materials handling and pre-treatment. Developments in zinc management through the use of aluminium and nickel alloys are discussed. The paper addresses the cost components of general galvanising and relates this to the competitive position of general galvanising against other coatings used for protecting steel. The environmental aspects of the general galvanising industry in Australia are outlined with respect to the utilisation of process chemicals, problems associated with their disposal and developments in filtering and regeneration of process solutions. The current status of the industry is assessed in terms of zinc usage and usage trends. Likely changes in technology which may impact on the general galvanising industry in the future are reviewed.

Jan 1, 1993

By Brown P. L

A study has been made of the geochemistry of the Ronneburg mine district as input to the overall management strategy for the rehabilitation of the mine site. The study drew on the geological data and information store developed over the 40 years of mineral exploration and mining at Ronneburg, and on chemical data from the literature which described the chemical processes of weathering, oxidation, dissolution and precipitation of minerals. The geochemical processes were divided into three groups based on their rate of reaction. Fast processes were assumed to proceed to equilibrium and were modelled using equilibrium chemistry equations; slow processes were assumed to be proceeding at a quasi-steady state rate and were modelled using chemical rate equations; very slow processes were assumed to have no role in describing the geochemistry for rehabilitation purposes.

Jan 1, 1995