Search Documents

Krupp Polysius AG, FRG, in close cooperation with Prof. Dr. K. Schoenert, FRG have developed the principle of the high pressure grind- ing roll POLYCOM. The POLYCOM mill basically consists of two counter-rotating rolls of large diameter and relatively small width, one of which is fixed and the other moving in slide blocks. The pressure required for comminu- tion is applied via the sliding roll by a powerful hydraulic system. The comminution takes place between the rolls under high pressure in the bed of material by nipping and compacting. The top feed size-depending on the rolls diameter -may be as coarse as conventional secondary crusher feed and the product is a compacted cake containing a high amount of fines created by micro-cracking. The amount of fines depends on the pres- sure (grinding force) applied. Operating results show that even in wet griding circuits capacity increases at downstream connected grinding mills of up to 100010 can be accomplished with an interconnected POLYCOM machine and energy savings of up to 25070 may be achieved depending on application. POLYCOM can be used in existing grinding plants for low-cost upgrad- ing of capacities but also as an advanced alternative to conventional crush- ing and grinding equipment in open or closed circuit configuration. A single industrial size 2.8m roll diameter POLYCOM machine may be fed with top feed size of up to 200mm and produce a finish product as fine- grained as known from rod and ball mills but with less energy consumption. Meanwhile, the POLYCOM high pressure grinding roll has established itself world-wide in the cement industry and is now entering the mining industry. POLYCOM machines are currently designed in industrial standard sizes of 1.0m to 2.0m rolls diameter and drive units of up to 2400 kW. This paper includes: principles of high pressure grinding, main fea tures of the POLYCOM machine, results of tests on various materials including Australian gold and copper ores carried out at the POLYSIUS research centre in Germany. Some examples of industrial applications of high pressure grinding will also be presented.

Jan 1, 1988

The Australasian Institute of Mining and Metallurgy brings together, voluntarily, people with a professional interest in the disciplines and skills which are employed in the mineral indus- try, and in relation to that industry. We come together because we have a mutual interest in improv- ing what is done by the mineral industry, in all its aspects. It is this sense of continuing improvement, of doing better, of doing as well as we can, as our knowledge and skills improve, that unites us in creating and fostering a professional association of like- minded people. We know from our professional training and experience that enormous progress has been made, at an ever-increasing rate, in the mineral industry, particularly in this Century. We know that the mineral industry has played a very major role in providing the means by which so many more people survive to live longer, healthier and more interesting lives, than ever before. Indeed together with the oil and gas industry, which is an integral part of the mineral industry but has achieved its own commercial dis- tinction, it is fair to claim that the mineral industry has played the major role in providing the means for the advancement of the human quality of life.

Jan 1, 1988

In order to formulate appropriate and useful education and training policies and practices, it is crucial to firstly consider the demographic environment of our workforce-and the direction in which it is (known to be) heading. We can predict with a degree of certainty, that the role and influence of training on the future survivability of organisations will- become increasingly critical. This will be particularly relevant for those industries and organisations which are technologically based. The ad-hoc use of training is and, will no longer be appropriate. Organisations must move toward the on-going use of a dynamic education and training strategy based on an effective staff development programme, which meets the short and medium term needs of the organisation. The Technisearch approach is based on maximizing the efficacy of training and learning. The package provides.a total service to meet clients training needs using educational techniques geared to adult learning. it stresses the importance of ongoing research into industrial adult training and its effectiveness in improving skills and productivity. Current research on roles of supervisors in the Australian workplace and the development of the Supervisory Behaviour Questionnaire. (SBQ) indicates the need for a proper framework within which the objectives of training can be addressed.

Jan 1, 1986

The geochemistry of waste rock from mining operations is critical to the development of acidity-related environmental problems during mining operations, and following mine closure. Failure to recognise the potential for waste rock to produce acidic oxidation products may cause mobilisation of heavy metals into ground and surface waters, and create heavy metal levels in soils which are toxic to plants, causing the failure of revegetation programs. Although more usually associated with wet tropical environments, the potential exists for these problems to occur even in and regions such as the Eastern Goldfields region of Western Australia unless appropriate pre-planning is undertaken.Acidity-related mine waste problems can be extremely expensive to rectify, but can be avoided by waste rock characterisation, and pre-planning of waste rock deposition based on this information. Integration of knowledge of waste rock geochemistry with geotechnical engineering, and application to likely problems, is essential for the successful planning and implementation of cost-effective strategies to avoid problems occurring. Pre-planning to avoid problems is likely to be significantly less expensive in most cases than remedial actions to rectify problems after they have occurred, and in fact may involve no additional cost if it requires only rescheduling or redesign of existing or planned Activities.

Jan 1, 1993

We have been exploring for minerals in Australia for over 100 years and our methods are constantly improving - but why do we pros- pect? Is the effort justified? Obviously the main motive is economic gain. It is now and always has been but conditions are changing rapidly. Once it was the prospector who could cash the nugget. Then it was the syndicate, the small company, an amalgamation of small companies, the large company, the corporation; the multinational corporation - where do we go from there? Early there was personal satisfaction and excitement in out-door activity which gave scope for individual energy, hope and in some cases reward. There still remains the satisfaction, either individual or corporate that a mineral discovery creates new wealth and makes a contribution to the nation's well being. Parallel with developments has always been the growth of restraints on exploration, frequently out of phase with the current mineral developments - miners' rights, licences, titles, royalties, mining laws and regulations, taxation etc. As the operations have become more complex so the restraints have become more confining until it is now very necessary to question whether the chances of economic gain justify the risk and responsibility of mounting costly mineral exploration leading-to extensive capital development.

Jan 1, 1974

The Geological Survey of the U.S. Department of the Interior is primarily a domestic agency whose responsibility is furnishing impartial data and analyses to the public, private, and academic sectors of the Nation. The Survey concentrates on earth-science issues, such as mapping the land surface, determining the quality and quantity of water resources, estimating the nation's endowment of fuel and nonfuel minerals, and predicting and mitigating geologic hazards, such as those inherent in the tectonically active Pacific Rim. One of the challenges to managing this program is striking a sustainable balance between concentrating on the problems society wants solved today and investing in the research that seeds our vitality for the future. The Geological Survey's role in the Pacific results from the Nation's geography and the Nation's long standing interest in and commitment to the region. The longest segment of the U.S. coastline borders the Pacific Ocean, one of our states is a Mid-Pacific island chain, our lands are 80 degrees--nearly one-fourth--of the Pacific perimeter, and our Exclusive Economic Zone (EEZ) underlies significant parts of the eastern, northern, and central Pacific waters. Thus, the program of marine and terrestrial science operating in these areas make substantial contributions to the world's growing understanding of the Pacific realm.

Jan 1, 1990

By P Andersson, P Marklund

Evaluation of different techniques for bottom fill stabilisation showed that frozen fill was the most economical method. In order to test the method a full-scale field test was performed in the Rehnstr÷m mine. The test was instrumented with temperature gauges and extensometers. Before the field test, frozen fill was tested at the laboratory. The mechanical properties of the frozen fill were determined by uniaxial compression and creep tests. A deformation model for the frozen fill was set up. Calculation procedure for design of spacing between the freezing tubes, time for freezing and calculation of the necessary capacity of the refrigeration plant was developed. These procedures were calibrated against the field test. The results of these investigations allow the following conclusions: From a mechanical point of view, frozen fill has excellent properties as a structural member and it also has excellent properties to support itself and the fill above. Methods for the thermal and mechanical design of freeze stabilisation have been developed and found adequate. The need to place the freezing tubes several years in advance of the future sill pillar mining, requires careful long-term planning and accurate documentation.

Jan 1, 1998

The types of risk to mining projects using environmental protection as justification are examined. In Australia, Governments, whether Federal or State, enforce environmental legislation. The way they do This has an impact on the risk to a project. This is discussed and examples are taken from the Northern Territory uranium industry. Special reference is made to mine closures where the roles are not yet entrenched.

Jan 1, 1994

By D I. Cliff, K Johnstone, N LaBranche

The resurgence of silicosis and coal worker’s pneumoconiosis (CWP) in mining and the recent ban of engineered stone products underscore the need to comprehensively address mineral dust exposures and the associated health hazards. Worker exposure to particulate matter, remains a pressing concern demanding nuanced exploration as all dusts are not created equal. The established link between silica and respiratory diseases necessitates a more detailed understanding of the characterisation of particulates and their health impacts. While current monitoring relies on total mass, it is increasingly evident that the size, shape, mineralogy and agglomeration of particles play a crucial role in determining health impacts. This has been evident in the engineered stone industry with workers not only facing a greater risk of silicosis, but also seeing a faster progression of the disease and a higher likelihood of dying from it. Simultaneously, the surging demand for critical minerals, integral to low-carbon economies, has seen government and industry fast tracking the exploration, mining and processing of these commodities. Critical minerals, crucial in technologies like lithium-ion batteries and high-performance alloys, are central to achieving global environmental goals. Significant funding is currently being allocated to advance the development and processing of these materials, however there remains a considerable gap in understanding potential health risks, urging comprehensive health risk assessments. To tackle these challenges, the University of Queensland has developed innovative dust characterisation methodologies, including the use of the Mineral Liberation Analyser (MLA), a scanning electron microscope, to characterise respirable and inhalable dust samples. This advanced technique, initially applied in coal and metals mining, is expanding to critical minerals mining, unravelling diverse mineralogical components and particle size distributions. This conference presentation will showcase the latest research, emphasising the use of advanced analytical techniques to deepen our understanding of the size, shape and mineralogical composition of particulate matter. By synergising insights from coalmines, metals mines, smelters, engineered stone and critical minerals assessments, we aim to proactively manage health risks, contributing to safer workplaces and responsible production practices in the mining sector.

Apr 16, 2024

In many metal mines in China,the 70B2 series of fans has been used for main fans for a long time.These fans generate higher static pressures than are required for the relatively high equivalent orifices of the ventilation systems of many of the mines. As a consequence, their running efficiency is common only around 30%. The loss of power is significant.

Jan 1, 1988

It is a well known fact that the best method of rock reinforcement is to avoid physical ground support. This goal can be achieved by means of: - Increasing the rock structural strength - Geological definition and forecasting. - Sequencing the excavation - Smooth blasting In many cases however, extra ground support is needed in order to maintain safe working conditions. In an open pit, the structural strength of rock cannot be increased by lowering the pit walls due to economical reasons. Economy demands steeper walls and less waste to be hauled to the dump. The geological conditions can also often be extremely poor and unpredictable. For excavation sequencing and smooth blasting there are good possi- bilities, such as cleaning of the pit walls after the main excavation, arul- ing of long small diameter straight inclined holes, use of smooth blasting techniques and lightened explosives.

Jan 1, 1989

In-situ leaching of gold deposits has not become an option largely as a result the lack of suitability of cyanide as a lixiviant due to sluggish kinetics and high dependence on the availability of oxygen. A second problem area is the excessive cost of drilling the required number of injection and production wells needed to service a wellfield capable of maintaining any significant throughput or providing and acceptable level of gold production. Well spacing in in-situ leaching operations is limited by solution life, dissolution rate, and the need for solution control. With cyanide the life of an active solution capable of dissolving significant gold is severely limited by the availability of oxygen which cannot be readily replaced while the solution remains underground. The extremely slow gold dissolution rate also necessitates excessive contact periods in order to dissolve coarse gold.

Jan 1, 1991

Continuing education is recognised as an essential aspect of professional training, but no systematic procedures have hitherto been attempted. The tertiary educational institut- ions are making a valuable contribution without formal financial support. The Australian Mineral Foundation is offering a programme of continuing education in the earth science and related disciplines both by direct initiative and by co-operation with existing tertiary educational institutions.

Jan 1, 1974

By Golledge P

Safety legislation has a long history and widespread application, but how can one test its effectiveness? One way is to examine safety statistics. Another way is to compare the legislation with principles of good safety practice. Mine safety legislation contains many features that are widely accepted, and these should be examined critically to determine their importance. Uniform legislation and revision of legislation should be considered. INTRODUCTION

Jan 1, 1975

By Churchill J

A suite of software programs has been written to provide the field engineer or geologist with the capability to collect and store data directly into small, portable handheld computers. This allows the engineer and geologist to collect data in a more efficient manner as the data is collected in sequence and is verified at the time. Typical applications for this software include geological and geophysical logging, trucking surveys, mine surveying, condition monitoring, ventilation surveys and maintenance systems. The software allows the user to construct his own electronic notebook by structuring data input to the computer in a similar manner as is now done on pre-printed forms. The user can store all valid entry codes or numeric ranges in a dictionary and all data inputs made are validated against this dictionary. Once constructed the user may call the electronic data sheet into the unit and collect data which will be stored into the unit which has the memory capacity to record data for up to periods of 60 hours. The data can then be automatically transferred to mini/microcomputers for immediate analysis and report generation. The software may be used on a variety of handheld computers.However the generally rugged environments found in the mining industry limit the choices. In particular the authors have selected a unit weighing a little over one kilogram, which is rugged enough to fall off an underground survey vehicle, and survive when accidentally immersed in water,without losing data. This paper describes the software developments in detail. The project development work to produce this system has been funded by a grant from the Australian Mineral Industries Research Association and is supported by a number of large Australian mining companies.

Jan 1, 1986

By Thulin D

In 1971 the first Grangcold Pelletizing Plant came into operation at Grangesberg, Sweden where from a rich magnetite low- phosphoric concentrate and a cement binder (Portland cement clinker and granulated blast furnace slag) self-fluxing blast furnace pellets are produced.

Jan 1, 1974

By P K. M Mazzoni, D Frantois-Bong

This paper aims to show alternatives to the estimation methods used for finding the parameters in GyÆs well known model for sampling variance in the case of particulate materials. Many experiments designed for gathering data on the sampling variance for specific mineral deposits allow the experimenter to use approximations in the calculation of the parameters of the mathematical model involved, which sometimes can be very useful. However, there are some instances where approximations lead to biased estimates of the parameters, and consequently, lead to errors in the establishment of the sampling protocol and treatment of quality control data. In the present work, an alternative is presented for computing the parameter values based in any experimental set up, without the need for any simplification. The method was derived using the method of least squares and evaluations are made using the usual tools in this kind of methodology: residual analysis and evaluation of the fit by means of a plot of calculated versus experimental variances. With the aid of these tools, one can better evaluate the structure of the experimental errors in such applications, and the adherence to the proposed model. In addition, it is possible to perform hypothesis testing for the equality of different sampling procedures in terms of sampling variance. The full mathematical details are given, together with an algorithm for applying the method, which can be implemented easily using any computer language. An illustration of the method is shown, considering the international work done in ISO/TC 102. This example is a determination of the minimum sample mass to be collected in iron ore shipments, in order to achieve a specified sampling precision.

Jan 1, 2005

By Howlett P. F, Courtley S

A problem with secondary breaking at one of the mines of Pasminco Mining led to a study of new rock breaking technologies. Many of the techniques being developed had emerged from the thrust in the USA for continuous drill=break excavation. Such approaches to rock breaking highlighted the applicability of what would normally be classified as tunnelling techniques, to the secondary breaking sector - and possibly the reverse. As a direct result of the investigations for suitable technologies, Pasminco Mining supported the development of two improved rock breaking methods specifically targeting secondary breaking, one of which could be applied to continuous excavation.

Jan 1, 1993

INDEX OF CONTENTSIntroduction.Systems of classification of coals.RankClassification of Australian coals.Defects of systems in use in other countries.Indexing by Fuel Ratio.Classification by Ultimate Carbon/Ultimate Hydrogen.Relationship between Fuel Ratio and ultimate composition.Suggested convention for classification.Origin and Evolution.Notes on directions of change of composition on Carbon Hydrogen chart.Summary and conclusion.Acknowledgments.Bibliography.Appendix.

Jan 1, 1948

An extensive railway construction prog- ram in the People's Republic of China has required the excavation of many tunnels in difficult ground, particularly in mountainous regions. Conclusions drawn from case histories permit guidelines to be formulated as to the optimum location of tunnel alignments in faulted and folded terrains, and also in karst regions. Geological factors adversely affecting durability of tunnel linings can be minimised by adoption of appropriate construc- tion practices.

Jan 1, 1987