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By Hoskings AD

Bolting forms a prestressed elastic layer of rock which is capable of supporting loads at right angles to the bolted surface. Investigations on rock bolting made with a number of different models give rise to empirical and theoretical prin- ciples for the formation and action of the layer. In the models, flat and arched layers of many materials were used simulating rock conditions ranging from closely interlocked blocks to fragments of various shapes. Results of observations made in the underground works of the Snowy Mountains Scheme are related to the mode of action of bolted surface layers of rock. There is abundant experimental, theoretical and practical explanation for the well-demonstrated capability of bolting as a means of rock support.

Jan 1, 1971

By Jeffrey IC

This paper presents a method of measuring field power consumption of shearers and deriving specific energy consumption versus shearer haulage speed performance curves. A description of a computer program which simulates the cutting action of a shearer drum is presented. A comparison between the field specific energy curves and the computer simulation results is made. The simulation results compare well with the field data where all the coal seam is being cut by the shearer. The computer simulation results give back-calculated field pick force cutting characteristics, which allow the performance of the shearer to be predicted for other operating conditions, e.g. effect of changes to pick lacing, effect of changing the drum rotational speed, allows the calculation of power requirements for a particular production rate.

Jan 1, 1992

By Tronson K

Improvements in technology do not necessarily lead to higher profits: the benefit of lower costs can be captured by coal buyers, governments and workforce rather than by the colliery operators. The economic impact of longwall mining in Australia has been critically assessed to provide lessons for the future. For a variety of reasons, companies investing in longwall equipment in the past five years have generally not achieved an adequate return on the funds invested. The effect of technological innovation must be examined in the light of competitive forces operating in the market. Projections of cost reduction trends in the coal industry have been applied to a world cost model to provide a picture of the coal industry in the year 2000.

Jan 1, 1988

By Davis A, Song J

A review of the literature indicated that several studies have been reported on the dissolution of gold using iodide/iodine, bromide/bromine leaching systems. Although the reagent costs are much cheaper for chloride/chlorine (or hypochlorite) this system has not been fully evaluated. This study was conducted to evaluate the fundamental chemistry of the chloride/hypochlorite leaching system. The CHEMIX program was used to model the stability of various gold species existing in the solution. The gold dissolution rate at different conditions was determined using gold strips immersed in various mixtures of chloride/hypochlorite. Leaching experiments were conducted to test the extraction of gold from various ores (oxidised and copper-gold ores), showing a promising prospect for this technique in various applications.

Jan 1, 1992

The techniques used by the State Electricity Commis- sion of Victoria to handle and store brown coal in the both the raw coal and boiler bunkers are outlined. These tech- niques were adopted in agreement with the science of modern bulk solids handling. By successful balance between practical requirements and bulk solid handling system design require- ments the Commission expects to confidently attain reliable coal flow even for the most adverse of coal flow properties. Attainment of this goal demanded full attention to channel detail selection. An outcome of this attention has been the development of a novel bunker and discharge arrangement for handling extremely difficult to handle coals. Due to the novel features of this slot bunker outlet arrangement it's ad- vantages and disadvantages are discussed.

Jan 1, 1987

By Singh TN

Rampura-Agucha Zinc-Lead deposit is unique as it is reported for the first time in the gneissic terrain with a rich oregrade quality of early to middle Proterozoic of Bhilwara supracrustal belt in the Precambrian of Northwest India. These sulphide ores are mostly confined to the graphite bearing Quartzofelspathic gneisses with intermittent bands of Calc-Silicate granofels and amphibolite. The ore and country rock mineralogy and their textural features are indicative of highly metamorphosed deposit and further the presence of marmatite and monoclinic phyrrhotite revealed high temperature environment of deposition.The present paper deals with some of the ideas about the ore genesis and petrographics of the associated rocks for Rampura-Agucha Zinc-Lead deposits of Bhilwara District (Rajasthan).

Jan 1, 1990

Whilst decisions to commit projects have traditionally been heavily influenced by hurdle rates for d.c.f. analysis, it is suggested that evaluation of competitors' costs may be a desirable additional tool.The MICAS system developed over the past four years is described. This computer system uses standard costs modified by District and Mine factors to allow estimation of individual mine costs. The data base contains more than 15,000 items of data and more than 6000 costs are calculated.Recent applications include use for competitive analysis, predictive analysis, statistical analysis, and comparative assessments with scopes ranging from a few mines to the whole Australian export industry. Some areas where care is necessary are outlined and potential further uses are discussed.

Jan 1, 1985

By K Biegaj

During the author’s 25+ year career in mine management in various parts of the world (mostly in Australia), the author has been privileged to live and work in mining towns (not FIFO) for more than 20 years. And has personally observed other people from the mining industry carrying out work at home in an unsafe manner, eg pushing lawn mowers whilst wearing thongs or performing electrical jobs whilst standing on aluminium ladders, as well as many others. It is common that injuries sustained at home whilst on break are not reported upon arrival back on a mine site. A large number of compensation claims for injuries at work, which in fact had been sustained at home, come at substantial extra costs to mining companies.

May 5, 2022

By Bailey S, Avraamides J, Jayasekera S

The anodic dissolution of iron from three different Western Australian reduced ilmenites was investigated using the carbon paste electrode technique. A characteristic current-potential diagram, called a cyclic voltammogram (CV), was obtained for each of the reduced ilmenites. The shape of the CV measured for all three reduced ilmenites was strongly time dependent. The effect of electrolyte composition and temperature on the CV of one reduced ilmenite was also investigated. The results suggest that the initial surface of iron in reduced ilmenite is slow to dissolve and that chloride ions and higher temperatures accelerate the dissolution of this initial surface layer. However, after removal of this layer, the dissolution rate was essentially independent of the electrolyte composition and the temperature.

Jan 1, 1996

By Restarick CJ

The development of mathematical relationships to describe grinding in continuous rod and ball mills has involved two methods of approach and has resulted in two main types of "model." The first which has been used for full scale grinding systems has depended on the analysis of, for example, the effect of change in solids feed rate on the changes in overall size distribution which the feed undergoes to become the product as a result of passage through the mill operated under steady conditions. The resultant mathematical relationships are of matrix form and do not include any description of the flow characteristics of the systems. The second approach has made extensive use of a technique in which a "pulse" of selected tracer mineral, of chosen

Jan 1, 1970

Because of the work of the pioneers of sampling theory, we know the principles, test work and equations to use to design sampling systems to meet targets for precision and accuracy. However, we do not see such æproperÆ systems deployed everywhere a sample is obtained around mineral processing plants. In many cases, we do not have solutions that satisfy all of the theoretical, economic and practical considerations. There are some well-known problems, such as high-volume streams with wide size distributions combined with a sparse valuable component that is heterogeneously distributed (such as gold ore SAG mill feeds). However, other difficult sampling issues are common, such as streams which vary widely over a day in flow rate and slurry density (many flotation concentrates), and loaded CIP carbon on transfer to elution. Inventory measurement issues abound, especially for leaching operations where daily inventory change is significant for metallurgical accounting. The result is that operators realise that although they issue reports daily, they do not know what is actually going on in their plant on a daily basis with sufficient confidence to quickly diagnose problems or confidently predict the benefits of potential enhancements. The industry needs practical and economic solutions that can be awarded the ætheoretically correct samplerÆ tick in order to better understand and optimise their processes.

Jan 1, 2008

Australian contract mining as it is known today had its origins in the early-1980s. Before this time there were numerous examples of underground mine development, and specifically shaft sinking being carried out by contractors. However, these were typically international contracting companies who came to Australia for specific projects. Growth in the underground mining industry in the 1980s opened up the opportunity for contractors. Mine owners had a need for contractors who could bring technical and operational capabilities to a project combined with capital in the form of equipment. In the early years the contracting industry was dominated by smaller players who focussed on mine development. The relationship between mine owner and contractor was loose and typically contract documents were rarely referred to. Through the 1980s and 1990s the underground contracting industry in Australia grew to where today there are over 20 underground contracting companies operating in an industry with an estimated annual value in excess of $1 billion. Of these 20 companies approximately five dominate with annual turnovers exceeding $100 million. Underground contractors now provide all facets of underground mining including development and production. Over the last 20 years the underground contracting industry has been able to consistently lower costs to mine owners through a combination of:equipment productivity, labour productivity, and technical innovation.

Jan 1, 2002

Asian countries are now facing very crucial aspects of urban living under the recession of the economy. The current situation is such that those hard aspects may make the living standards worse and worse in the next century, unless proper measures are taken on the infrastructure for urban lives. More than half of the population in Asian countries are now living in cities. Nowadays, the socio-economic development of the Asian countries has been closely linked to the development of world economy because of the border-less economy system. The population inflow to big cities is inevitable as the Asian countries step into an industrialised economy. Such a tendency will be further accelerated when Asia becomes a centre of financial business in the 21st century. The government of any country has realised the situation very well. The United Nations has established a specific agency to solve the problems caused by the rapid urbanisation. This global agency for urbanisation is named United Nations Center for Human Settlement and it is so called Habitat. There are three Habitat offices in the world, Nairobi in Kenya, Santiago in Chile and Fukuoka in Japan. The activities of Habitat offices cover a wide field of issues such as housing, urban development, infrastructure and environment, etc. Habitat Fukuoka Office is serving Asia and Pacific in co-operation with the government offices concerned.

Jan 1, 1999

This paper considers the standard of ore reserve assessments required by lenders when presented to support requests for project based loans. The way lenders use this information to structure a suitable financial package shows why ore reserves should be measured by industry set standards. This in turn raises questions concerning the assumptions used to derive mineable reserves from geological reserves. Consideration of the variety of related problems highlights the need for assessments to be defined according to acceptable standards. These should also address the suitability of the methodology to the assumed configuration of the orebody; the degree of variance and relaibility of estimates of grade and tonnage presented; and the estimation of probability that ore will in practice fall within the defined limits. In an increasingly international marketplace it is appropriate to compare Australian industry requirements to those of similar overseas industries, in this case the United States. Lenders would like to see that individuals responsible for the preparation of ore reserve estimates are certified on the basis of their skill and expereince by an industry body such as The AusIMM. The paper discusses how each of the parameters indicated above may impact upon a lender's assessment of the viability of a project. A number of practical examples are presented where inaccuracies or inadequacies in ore reserve information have led to reduced project performance.

Jan 1, 1987

Zinc produced by pyrometallurgical processing techniques suffers the disadvantage of restricted market potential because of its impurity contents, typically lead and cadmium. Market zinc to the Special High Grade (SHG) standard can only be produced by reflux distillation refining, which is costly in terms of energy and equipment, and potentially capacity limiting. Recent published laboratory work suggested that molten salt electrorefining of zinc metal is a potentially much cheaper alternative to the reflux distillation refining. The extrapolation of the laboratory results to an industrial configuration, however, resulted in an estimated power consumption for electrorefining and associated costs offering no advantage over current reflux distillation practice. A review of this estimate now shows that a serious error in calculation was made, and that the energy consumption for the electrorefining of molten zinc would be an order of magnitude lower than that for reflux distillation refining. While this is a promising indication, further research is required before development towards an industrial scale operation is warranted. This would particularly relate to the extent to which adverse electrolyte deterioration may take place and its potential effect on the anode and cathode efficiencies of the process. This paper considers the laboratory investigations required to explore the industrial potential of the molten salt electrorefining of zinc and foreshadows some of the practical problems to be solved in further development.

Jan 1, 2000

While there is reasonable agreement on the basic chemistry of the slag fuming process, there has been an on-going debate for nearly 50 years as to the nature of the rate controlling factors in its industrial application. There have been advocates in the technical literature for thermodynamic limitations on the one hand or kinetic limitations on the other. The different viewpoints result in very different predictions as to the technical and commercial potential of the process. A resolution of the debate becomes of importance as pyrometallurgical processes are advocated as a means of extracting environmentally deleterious elements from metallurgical wastes. The present paper reviews the arguments in favour of both equilibrium and kinetic control and puts forward the view that much of the evidence for limitation of the process by kinetic factors under all conditions is unconvincing. It is maintained that the process can approach thermodynamic equilibrium under industrial conditions and that this determines the ultimate limitation on its technical performance. It is acknowledged, however, that kinetic considerations may cause the batch process to fall well short of performance predicted on thermodynamic grounds. The strong process limitation arising from the influence of chemical thermodynamics on the likely outcome of a hypothetical continuous fuming process is contrasted with optimistic forecasts resulting from the extrapolation of process models based only on kinetic considerations.

Jan 1, 2000

By S Choy

Aquatic macroinvertebrates have been used as a monitoring tool for many years. They are ubiquitous and occupy a central role in the ecology of rivers. They are a key link in the aquatic food chain, forming a pathway between primary producers (such as algae and macrophytes) and predators (such as fish, platypus and birds), and some are sensitive to flow conditions, water quality and habitat condition. They are not very mobile and are good indicators of local impacts. As most aquatic macroinvertebrates are benthic, they are better able to integrate effects of changes in water quality, and habitat condition and structure. Their diversity is crucial to the maintenance of a balanced, functioning and healthy river ecosystem. Thus, data on benthic macroinvertebrate community structures can be used for predicting potential impact, assessing the extent of damage and for gauging recovery from damage. Over the past eight years, State agencies throughout Australia, through the National River Health Program have developed models (AusRivAS) to assess river health using macroinvertebrate communities. The Queensland Department of Natural Resources and Mines has sampled both macroinvertebrates and water quality throughout Queensland, including areas affected by mine discharges. This paper will assess results obtained from sampling in the Mt Morgan area to illustrate the usefulness of this method of river health assessment.

Jan 1, 2003

Sulphide Corporation Pty. Limited operates a Lead/Zinc Smelter at Cockle Creek, some 11 miles from Newcastle, N. S. W . Works effluents totalling some 8, 500, 000 gallons/day join Cockle Creek some 1. 8 miles from its mouth in the most northerly section of Lake Macquarie, The Creek is also the source of the Works cooling water intake of which approximates 8, 000, 000 g.p. d. In view of the wide use of the Lake for recreational activities by the people of Newcastle and the surrounding areas, particular care must be taken to ensure that the control of effluent quality is of a high order. This paper outlines the philosophy and measures taken for the treatment and control of plant effluents discharging into Cockle Creek.

Jan 1, 1971

By K H. Esbensen

The critical role of representative sampling is featured and illustrated by selected examples from the geosciences and beyond. As there already are many demonstrations of the potential (and potentially large) economic consequences of ignoring proper standards with respect to representativity, eg for mining and minerals processing companies, which æstand to lose millions of dollars by failing to optimise exploitation of their mineral resourcesÆ, such need no further iteration here.This keynote lecture, rather, takes a point of departure from the opposite perspective: what is to be gained by a scrupulous stand for representativity? Honesty, reputation, credibility, market advantage - is what!CITATION:Esbensen, K H, 2012. The critical role of representative sampling, in Proceedings Sampling 2012 , pp 9-12 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 21, 2012

By Stevens LG, Mok JK

With the long lead time requirement for engineering and construction of mineral pro- cessing facilities and the costly financing arrangements necessary, effective project management is essential to the successful and timely start up of these major production units. An added complexity is the frequently remote location of such projects and the demands this imposes on efficient project staffing, scheduling, logistics and cost control. Parsons recent experience with major projects such as Greenvale in Queensland and La Caridad in the desert of Northern Mexico and at remote locations like Sar Cheshmeh in Iran are described. The applications being developed for improving project controls through the use of computer techniques such as MSCS-COPES, and readily accessible and versatile transportation means are reviewed.

Jan 1, 1981