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A nuclear technique utilising the gamma-ray resonance scattering process is used at Isa Mine for the determination of copper in drill core and bulk mineral samples. The Copper Bulk Analyser (CBA) provides quick and accurate non-destructive copper analysis of drill core at costs two to three times cheaper than conventional chemical techniques.The almost immediate availability of sample results enhances the efficiency of the mine geologist in the duties of grade control, design of diamond drilling programmes, and input to planning. The unit has proven to be a reliable and accurate production tool requiring a minimum of technical support.

Jan 1, 1990

By D Baas, Y Atasoy

With increased pressure for companies to cut costs during design of new mineral processing plants, overall plant design has changed over the last decade with less design for feed blending and less installed surge capacity. This has changed the operability of new mineral processing plants, where disturbances due to variable ore types have resulted in the evolution of new control techniques. These techniques are necessary to maintain stability and optimise the performance of these new plants. This paper describes the benefit of applying these new control techniques in a new mineral processing plant in Australia utilising RockwellÆs ControlLogix system architecture.

Jan 1, 2008

Preliminary petrographic investigations of eight Upper Permian coal seams of the Muja sub-basin, Collie Coalfield, reveal that the coal is high in inertinite and relatively low in vitrinite and exinite contents. The exinite content of Collie coal is relatively high when compared to other Australian coal of similar age. In addition the mineral matter content of the coal is very much lower than comparable Permian coal of Eastern Australia. The higher exinite content could be attributed to the type of Glossopteris flora, and the lower mineral matter content to the environment of deposition postulated for the Collie Coal Measures.

Jan 1, 1982

There are many variables in a flotation concentrator, some of which are outside the actual flotation stage, which affect metallurgical performance. The number of such variables which can now be measured on a continuous basis has increased significantly over the past 20 years. They can be broadly classified under the headings of physical, chemical, and elemental. In this paper reference is made to a number of such variables, and comment is made on the state of the art in their measurement. Although not confined to development in Australia, particular reference is made to the considerable Australian contribution in this area of Technology.

Jan 1, 1984

Methane predrainage from coal seams in the Western Area of the U.K. has been practiced over the past decade. The differing reasons for the practice include the controlling of gas emission rates in coal headings required to win out coal faces and also the need to control the gas emission rates in the roadways of retreat faces in order to comply with the statutory requirements. There are some similarities with predrainage experience in the Bulli Seam NSW. The several case studies highlight the varying conditions in the Western Area coalfield where the use of predrainage was Required.

Jan 1, 1982

Applications of chlorine metallurgy to the extraction of metals often result in the production of volatile metallic chlorides, most of which condense directly to a solid phase at one atmosphere pressure. A stirred bed condenser suitable for th

Jan 1, 1980

By Valery W, Morrell S, Loughlin P, O&apos

Traditionally, blasts in mining operations are designed to prepare the in situ rock mass for excavation and transport without much consideration being given to the downstream comminution processes. Blasting is in fact the first step in a chain

Jan 1, 1998

The paper examines the difficulties encountered by objectors to mining privilege applications. It describes the various involvements of the environmental defence society in the mining controversy and makes some comment on the proposed amendments to the Mining Act 1971.

Jan 1, 1981

By Y Lin, B J. Seligmann, M Hassall, S Micklethwaite

For multi-site mining companies, checking the quality and consistency of the data recorded in risk registers is important for confirming how well mine safety management systems have been implemented. However, this task is complicated by the differences in scope of the site, their particular nature, the complexity of the operations and many other factors that can introduce nuances to the characteristics of the risk registers. We present here an application of a technique called Causal Network Topology Analysis for comparing the quality and consistency of risk registers. By quality we refer to, for example: - missing causal relationships between risks - location of missing controls - focus of risk treatment strategies: prevention versus mitigation controls. By consistency we refer to how causally interdependent are the risk events. There are often causal interactions between the lines of a risk register that mean that the likelihood and consequence scores that are applied to each risk event are not independent. We measure this degree of interactions by: - proportion of independent scenarios per register - efficiency of risk treatment strategy comparison. This approach can indicate quality and consistency differences between registers irrespective of the actual details of the site or operation. This occurs by comparing aspects of the structure of a causal network extracted from how the risk events, causes, controls and consequences causally interact. In this work we compare pairs of registers to demonstrate the approach.

Apr 16, 2024

By P Hatherly, A Melkumyan, D Wyman

Chemical species distributions in rock sequences can be modelled using Gaussian processes (GPs) to predict the weight percentage between known data points. This method can be improved by dividing the modelled area into regions of different mineralogy. In the context of many iron ore deposits, marker shales give the initial guidance of where these regions may lie. These shales give rise to distinctive peaks in the natural gamma downhole logs, which are conventionally identified by hand. A GP method has been developed to automate this task.Once the appropriate boundary has been located on the basis of shale occurrences, chemical assays from exploration drill holes are used to find the exact boundaries of interest. These boundaries divide the drill hole stratigraphy into regions of different mineralogy, each of which display their own distinct correlations between the main elements and oxides (Fe, SiO2 and Al2O3). Iron ore shows a negative correlation between Fe and Al2O3, but in banded iron formation (BIF) there is a positive correlation between these species. Similarly, SiO2 and Al2O3 have a positive correlation in the shales and ore but a negative correlation in the BIF. Correlations obtained within ore-, BIF- and shale-dominated regions are therefore better than those obtained using the entire log and can be used to improve the results obtained when modelling.

Sep 26, 2011

By Crawford M

During the initial development of Mount Isa Mines power was supplied from a temporary power plant situated near the Man & Supply Shaft. The main power plant was placed in service early in 1931 and then comprised two Babcock and Willcox boilers, fired by pulverised fuel, and two British General Electric Company's turbo-alternators of 5,000 kW. each. Both plants have been described by A. F. McAskill in the Journal of the Institution of Engineers, Australia.From 1931 power demand progressively increased due to greater production, further mine development in the harder sulphides increased pumping for mine drainage and additions to mill and smelter until, by 1935, the plant was inadequate for further output commensurate with a reasonable safety margin.Coincident with the added power demand, operating conditions involved a fuel problem which could not have been anticipated. The ash content of the fuel supplied gradually increased from 13% to 16-5%, while the melting point of the ash decreased with higher pyrite content.Temperature conditions in the furnace required careful control to cope with ash formation and slag accretions.Consequently brickwork, excessively stressed on water walls, was constantly under repair, and required suspension periods of 50% of operating time for cleaning and overhaul.Load conditions varied continually, therefore the high heat liberations in the furnace, necessary to accommodate peaks in fluctuating output, resulted in ash fusion.

Jan 1, 1939

By See J. B

The zinc-nickel alloy process, TECHNIGALVA, was developed for the control of the thicknesses of zinc -coatings on reactive silicon-killed steels. These are steels containing between 0.04 and 0.15 per cent silicon which have become more common in recent years as more steel is produced by continuous casting. The introduction to this paper will review the current status of this process in Europe, North America and Australasia. It is well known that the presence of silicon at certain levels in steel can cause sufficient growth of intermetallic phases during galvanising to form a grey coating of excessive thickness. This type of coating is undesirable because it is brittle and has poor adhesion to the steel base. Since the early-1980s a widely accepted practice for suppressing the reactivity of steels containing silicon during general galvanising has been the addition of approximately 0.1 mass per cent nickel to the galvanising bath ie the TECHNIGALVA process. The paper will also discuss metallurgical aspects of the use of nickel in galvanising such as the mechanisms by which nickel suppresses reactivity, the structure and composition of the ternary Zn-Fe-Ni drosses formed when using nickel and the use of nickel in the galvanising bath at a level of about 500 ppm to give thinner, smoother and brighter coatings on steel.

Jan 1, 1993

It has become increasingly clear in recent years that human kind has developed the capacity to alter the environment of the Earth on a global scale. The changes are often subtle. This is particularly true in the case of stratospheric ozone. Ozone is produced primarily in the stratosphere, at altitudes in excess of 20 km, initially through the action of ultraviolet sunlight dissociating molecular oxygen. According to theory as it existed up to a few years ago, ozone is removed mainly by reaction with atomic oxygen. In the unperturbed environment, this reaction proceeds both directly, and by paths catalyzed by trace quantities of nitrogen radicals. Molina and Rowland [Nature, 249, 810, 1974] pointed out that decomposition of industrial chloroflurocarbons could in-troduce an additional source of radicals to the strato-sphere. Chlorine radicals are even more efficient than nitrogen in catalyzing recombination of oxygen atoms with ozone; models suggested that we might expect reductions in the vertical column density of ozone of as much as a few per cent over the next several decades. A reduction in ozone of x¦/a, by increasing the flux of ultraviolet sunlight reaching the surface, was predicted to result in an increase of about 2x% in the number of cases of skin cancer, with other less well defined impacts on the non-human environment for life.

Jan 1, 1990

By K Kuganathan, Y Potvin

Enterprise Mine at Mount Isa is to expand ore production from the current 1.4 to 3.5 mtpa by mining the 3500 Orebody, from which production is scheduled to start in February 1998 making this the deepest underground mine in Australia with its lowest mining horizon at nearly 1.6 km below surface. The following fill requirements were defined for the 3500 Orebody during the feasibility study: a minimum filling rate of 250 m3/h, a curing time of 28 days, and minimum free fill water. This paper mainly describes the investigation of high density and paste fills for the 3500 Orebody. The investigation covered all the key issues relating to fill option selection, including design criteria, material supply and demand assessment, drainage modelling, tailing dewatering method, mix design and a pump loop test. Results of the investigation indicate that both high density fill and paste fill are technically feasible. The investigation has led to the selection of a blended tailing paste for the 3500 Orebody as the paste option has significant advantages over high density fill in stope filling rates and fill reticulation. The blended tailing for paste fill is finer than Isa deslimed tailing but coarser than full plant tailing. The paste fill selected has minimum binder and tailing dewatering requirements while a relatively high filling rate is achieved.

Jan 1, 1998

This subject of paramount importance in many modern plants employed in the extraction of gold from ores by cyanidation, involves several considerations.With the old-type "slimes decantation" process, using several tanks of large dimension, installed at high capital cost, it was frequently possible to obtain good settlement over a protracted period, but the disability of indifferent response to subsequent filtration and washing of the residual pulp, after decantation of the supernatant pregnant solution, was often present.In modern cyanidation practice, the tendency is to reduce capital expenditure by continuous processing of the ore pulp in a plant of less volume, but capable of handling more tonnage through-put and yielding, coincidently, less residual dissolved gold in the final pulp residues.INHIBITORY FACTORS.These involve a study of the effect of the circuit water or solution employed in milling and treatment, the amount of "primary" slime occurring in the ore broken underground, the constitution of the "walls" underground, the inherent occurrence of colloidal slime in partially decomposed ore, and the presence of kaolinised and ferruginous clayey structures carrying payable infiltrations of gold values, to mention some of the troubles encountered in practice. Practically all the difficulties occurring are due to the presence of colloids (using the metallurgical as apart from the chemical definition of the term), either...

Jan 1, 1935

By P G. Fuller

The Woodlawn Mine near Canberra faced the challenge of poor ground conditions from the commencement of underground operations 1987. Talcose shears bounded the dense massive sulphides on both the hangingwall and footwall side of the orebody. In another area the talc existed not only on the edges of the orebody but through out it as well. The country rock was relatively weak shales compounded by a low stress environment that allowed the wall rocks to fall apart quite easily. The challenge for the operators was to overcome the poor ground conditions. This was done by attacking the problem from three directions:technology, how technology is applied, human relations and leadership by all levels of the Management team, and by ensuring that these processes meshed together well.Woodlawn in it early days as an underground mine enlisted the assistance of BFP (Formerly Barrett Fuller and Partners) as a second set of eyes to assist with the assessment of the ground control procedures. The results are discussed in this paper. The progression to this end result included:non-contract payment systems; ground control training for the full range of mining personnel; the development and enhancement of cable bolting and shotcreting equipment; the development of Practical Standard Work Procedures by mine operators; and innovative use of shotcrete and cables bolts to control extremely poor ground conditions.

Jan 1, 1998

By J Sarvinis

The design and operational aspects of fluidised solids transfer-cooling devices will be discussed in this presentation. The devices include air slides and fluoseals (also called seal pots, loop seals, etc), which are widely used in metallurgical plants and other processing plants. Cooling can be achieved while solids are transported in the solids transfer devices. The units combining solids transfer and cooling provide compact and clean plant layouts and also reduce capital and operational costs. Fluidised devices provide excellent gas-to-solids and gas/solids-to-surface heat transfer rates, hence high cooling efficiency. Fluidising gas, such as air, nitrogen or other gases, can be used as direct cooling mediums. Coolants such as water, steam and other liquid or gas cooling fluids can be used as indirect cooling mediums via tube coils immersed in the fluidised solids. The fluidised transport devices share some common features with fluidised bed equipment. The air slide is similar to a linear fluidised bed while the fluoseal is similar to a circular fluidised bed. Therefore fluidised bed design techniques are applicable to the design of the air slides and fluoseals. The heat and mass balance and temperature profiles of the devices concerned will be discussed in the presentation. The design criteria and operational philosophies of the critical components such as tuyeres and air spargers will also be discussed.

Jan 1, 2006

Strong markets for metals and energy over the past five years have supported equity and debt market funding to enable a new group of mining juniors to emerge in control of economic resources, some in regions with high investment risk. As companies drive these projects to development, production and positive operating cash flow, their Boards and CEOs are confronting important questions:Having achieved initial success, what is our longer term purpose as a company? Does the purpose originally described in the Initial Public Offering to raise equity remain wholly relevant? Given that purpose, how do we understand the available sets of opportunities and related risks? Should we be acquiring new assets or other companies, or developing the existing portfolio? What commodity sectors and geographies should we focus on? Or should we be conserving funds until asset prices or project costs provide greater assurance of value to shareholders? How do we translate that purpose into tangible goals that shape and direct the work of people in the organisation? How do we get the right work done in the face of high turnover and competition for capable staff? Drawing on the authorÆs career experience and on work undertaken by Heuris Partners, this paper provides a practical CEO framework for strategy development, organisation design and on planning the work of the business in the mining industry.

Jan 1, 2006

By Allen RL, Clifford BA, Wright JV, Bull S

The Bunga Beds of the Late Devonian - Boyd Volcanic' Complex is a well exposed succession of rhyolite, sedimentary rocks and minor basalt outcropping along the south coast of New South Wales. The sedimentary rocks vary from shallow water basin margin facies, to deep-water basin centre facies, and the majority of .the volcanics are associated with the deep water facies association. The volcanics are dominated by rhyolite domes, lavas and cryptodomes, whose margins are extensively autobrecciated and quench fragmented. In situ pyroclastics represent a very minor volcanic component and are restricted to the remnants of two small doors- top tuff cone successions. Pyroclastic debris is common in the sedimentary succession enclosing the volcanics and was clearly derived from shallow to emergent basin margin areas through mass-flow redeposition. The succession has bearing on the origin of the fragmental component of, the volcanics that host Kuroko- type massive sulphide deposits. The characteristics of these fragmental volcanics are not well documented. We suggest that based on the Bunga Beds,'Kuroko-type volcanic successions are dominated by coherent rhyolite/ felsic lavas and intrusive domes, autobreccias and hyaloclastites, that in situ pyroclastics are rare or lacking, and that redeposited volcanic debris is abundant. Pyroclastic debris is most likely to have been derived from shallow areas marginal to the deep-water volcanic centre that produce the Kuroko-type volcanics and sulphides.

Jan 1, 1987

By S Miller, R Smart, J Thomas

Single-addition and sequential net acid generation (NAG) experiments were carried out on natural and prepared samples with varying contents of organic matter and pyritic S. Results show that carbonaceous matter can produce significant quantities of organic acids during peroxide oxidation in the NAG test, which leads to overestimation of acid-forming capacity and misclassification of benign samples as potentially acid forming (PAF). Organic matter effects were most pronounced in samples with low S (less than 0.5 per cent) and total organic carbon (TOC) contents of greater than seven per cent. The single-addition NAG test will tend to overestimate acid potential in samples with little or no pyrite and high organic matter content, potentially leading to sample misclassification. High pyritic sulfur samples tend to show little difference in single-addition NAG acidities with increasing organic matter, and it appears that pyrite is preferentially oxidised by peroxide when present in significant concentrations (greater than one per cent pyritic S). In sequential NAG tests overestimation was greatest in samples with little or no pyrite, but highly carbonaceous (>20 per cent TOC) pyritic samples were affected in later stages as the pyrite was depleted. A modified NAG method is proposed to account for the relative proportions of pyrite derived acidity and organic acidity in a given NAG solution.

Jan 1, 2003