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By Reed M. E, Cloutt B

Particulate samples were taken from the gas space in the settler of the Kalgoorlie nickel smelter using a vertical sampling probe and a specially designed isokinetic sampling probe which also quenched the samples. The vertical sampler was found to give unrepresentative samples. Suction thermocouple measurements of the gas temperature were also made. Using the isokinetic probe samples were taken at four points ranging from near the base of the reaction shaft to the base of the uptake at depths up to 1.5 m into the settler. Dust loadings and the sizing of the samples were determined. These parameters were found to be most affected by sample position and depth. The dust loading decreased along the settler but increased with depth. The loadings varied from zero near the roof to several hundred g Nm 3 near the slag. The dust also became coarser with increasing depth into the settler. Examination of the samples showed them to consist of spherical particles the largest of which were about 500 microns in diameter. The dust was mainly composed of mixed iron/nickel oxides with a little sulphide.

Jan 1, 1991

By Miller RJ, Eager DT, Lama RD

For safe and efficient mining operations, it is essential that environment and equipment status be monitored. A system that gives quick access to status at any given time, and also permits quick analysis of their history, is required. Such a computer based monitoring system has been installed at West Cliff Colliery.The system is based on 2 super mini computers. Three major sub-systems monitor conditions in the longwall operations, environmental conditions in the intake and return roadways, status of the underground and surface installations, and mining and transport equipment.

Jan 1, 1985

The Australian Mineral Industry has to compete on world markets, so its mineral research has to be aware of overseas developments, it must be of world class, and it must utilise as many ideas as possible in order to solve those problems that uniquely affect Australian minerals processing. North American mineral and resource research may be taken as a guide to world government, industrial, contract, and entrepreneurial research trends and ideas. A number of interesting findings are noted that may guide Australian developments and strategies for the future, in minerals research and exploitation.

Jan 1, 1986

By Hempenstall J, English W

Mine management has a responsibility under the various acts of state parliaments for the adequate ventilation of existing workings. It also has a need to plan adequately for the ventilation of proposed workings. Future workings alternatives have become progressively more complex and ventilation planning of the various possibilities must be undertaken within an atmosphere of rapidly changing market circumstances, etc. Any non-optimal solution will prove more expensive than necessary on both capital and cost bases. Clearly these increasing and alternative ventilation demands of coal mines in Australia have multiplied the work load of ventilation engineers. Management in general has for some time been aware of the advantages of using computers for commercial applications such as payroll and stores inventory. However, while the hand held calculator has replaced the traditional log tables and slide rules for smaller engineering calculations, the larger digital computer has not made the same

Jan 1, 1983

By G D. Price

The Golden Blocks Goldfield is located in the Slaty Creek area,North West Nelson, about 20 km west of Collingwood. Alluvial gold was discovered in Slaty Creek in 1861. Gold was mined from quartz veins up to 1.5 m thick at nine mines from the 1890s until the closure of the Aorangi Mine in 1911. Total production from the Golden Blocks Goldfield is estimated at 46 000 ounces of gold. The Aorangi Mine was the largest mine, with a recorded production of 27 978 ounces of gold at an average grade of 36 g/t. Quartz veins containing gold and sparse sulphide mineralisation occur in a slightly metamorphosed, complexly deformed over-turned sequence of Lower Ordovician sandstones and shales. Primary gold mineralisation is associated with intensely deformed zones that occur near or at carbonaceous shale and sandstone contacts. Some eighty-five percent of all gold production (39 000 ounces) came from four mines confined to the stratigraphically lowest, most widespread shale unit. The quartz veins exhibit textures consistent with a hydraulic fracturing mode of vein formation with fissure infill vein types predominating over replacement textures. Stylolites of carbonaceous material and recrystallization features within the veins suggest multiple phases of deformation. The lack of wall rock alteration, and low primary fluid inclusion temperatures of 200¦ - 265¦ indicate that the ore fluids were associated with a low temperature epithermal system. A model consistent with similar mineralisation styles observed in Ordovician sediments from Pacific Rim occurrences is presented. The high grades (up to 100 g/t) mined from the upper levels of several mines suggests supergene enrichment processes associated with the Upper Cretaceous weathering surface. The Golden Blocks Goldfield has had no modern exploration. The most recent exploration was undertaken in the early 1980s. There are known acid intrusives in the area, with potential for the application of new models of intrusive-related gold mineralisation.

Jan 1, 2004

By S Farrokhpay, M Zanin

Although it is well understood that in flotation collection zone and froth zone are deeply interconnected, and reagents (and in particular collectors and frothers) cannot be selected without considering their synergistic effect, this concept is rarely applied in plant practice. The feed mineralogy also has an important role in how particles and reagents interact in flotation, which is sometimes overlooked by operators. In this work, a combination of batch flotation tests and froth stability measurements was used to optimise the collector and frother scheme for the flotation of a copper ore. The methodology was applied to an Australian copper plant which was experiencing high variability in froth stability in the roughers when the feed ore mineralogy was changing. It was hypothesised that chalcopyrite in the feed in combination with isobutyl-xanthate had a destabilising effect on the froth phase under the reagents scheme used. Froth stability was restored if a shorter chain length, less hydrophobic, xanthate was employed. It is apparent that the hydrophobicity of adsorbed films at the solid/liquid/air interfaces has a critical role in enhancing or reducing froth stability. Unstable froth causes a reduction in copper recovery in spite of a high collection zone flotation rate. The case study suggests that collection zone and froth zone can rarely be optimised independently of each other. With the laboratory procedure adopted, a more suitable reagents scheme was determined to respond to changes in the feed mineralogy, avoiding fluctuations in plant performance due to unexpected froth instability.CITATION:Farrokhpay, S and Zanin, M, 2012. Synergic effect of collector and frother on froth stability and flotation recovery - An industrial case, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 145-150 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By Lloyd F, Arnold D. A, Hagan T. O

This paper investigates the problems that are encountered in mining at extreme depths. It looks into the rock mechanic aspects, especially the high stress levels that will occur, and the hazard of rockbursts. Furthermore, environmental problems are discussed, with refrigeration and reduction of neat loads being major methods of maintaining ,sorkable conditions. The paper concludes that it will be of tmost importance to have a planning team of Tne highest quality to ensure that conditions are maintained so that work can be carried out safely and under reasonable conditions.

Jan 1, 1986

By P Bourke, S Ronkainen

Since the early days of flotation, process technicians have known that the speed at which the froth is recovered over the lip of the cell has a very direct and consistent influence on the grade and recovery of the circuit. No plant would deny that, even to this day, one of the most important aspects of a process technicianÆs job is ensuring that the froth is moving at a desired and controlled speed over the lip. Unfortunately, process technicians cannot watch the froth throughout the entire shift, as there are always other problems to attend to. A considerable amount of work has thus been done to develop a æsystemÆ that automatically measures the speed of the froth. This measurement would then be used in simple controllers to emulate the steps taken by the process technician in correcting deviations of the froth speed from its desired level. Many of the earlier attempts to measure speed were ineffective, as they were unable to cope with turbulence on the froth surface. The FrothMasterÖ instrument makes use of machine vision technologies to measure the speed of the froth over the lip of a cell at a very high sampling rate. This instrument produces an extremely reliable and accurate measurement of the froth speed (as well as other parameters such as bubble size and froth stability). As we will show, the effectiveness of the speed measurement in controlling the performance of the plant is a testimony to its reliability. Three FrothMasterÖ units have recently been installed on the Cadia Hills Gold Mine in New South Wales (Australia). The objectives of this installation were:to control the mass-recovery of two Tank Cells in series on the same level where differences in the hydrostatic head between the two cells result in the cells pulling inconsistently with respect to each other; control of the concentrate grade (per cent copper) from the first rougher; reduction in the frother consumption in the rougher circuit by monitoring the froth speed. A simple controller was designed to react to disturbances in the same way that human operators react. This was done after consultation with the metallurgists and the process technicians at Cadia. The controller had two functions: Stabilisation: The stabilising controller made use of three manipulated variables (level, frother addition rate and aeration rate) to control the froth speed to a setpoint. Optimisation: The optimising controller adjusted the froth speed setpoint based on deviations of the grade (measured in real-time by the OSA) from a setpoint. The plant metallurgist adjusted the grade setpoint based on information about the ore. The results from a 21-day trial have shown the following:The ratio of concentrate mass-recovery between two cells in series on the same level has been successfully balanced, thereby overcoming problems due to differences in hydrostatic heads. It is possible to control the speed of the froth, in mm/s, to within five per cent of its setpoint using the aforementioned manipulated variables. It has also been shown that, for reliable control, it is necessary to control more than just one variable (eg level or air). The grade of the first rougher concentrate has been controlled to within 0.3 per cent of the grade setpoint for long periods of time, which has important implications for the circuit recovery. The frother consumption has been reduced significantly. This paper will thus show that substantial progress has been made to demonstrate the value of using on-line froth speed measurements in flotation plant control to obtain real financial benefits.

Jan 1, 2000

By M Jones

Legacy tailings storage facilities exist within operating mine sites across Australia. These tailings storage facilities are often viewed as rehabilitation liabilities but with considered assessment may prove to be a resource. Extraction of such a resource might add value to operations by providing cash flow during the development of new mines; providing supplementary mill feed for existing mines undergoing step changes in operations; and supporting mine closure activities. Hellyer Gold Mines is successfully extracting and reprocessing sub-aqueous material from legacy tailings storage facilities at their Hellyer operation in north-west Tasmania. The Hellyer tailings storage facilities contain poly-metallic material from the Hellyer and Fossey underground deposits dating back to the 1980s as well as material from tailings reprocessing activities by other operators of the Hellyer site. Hellyer Gold Mines is reclaiming sub-aqueous material using cutter-suction dredgers and reprocessing on-site. Hellyer is the only operation of its type in Australia and few such operations exist worldwide. Key learnings around the estimation of a resource for legacy tailings storage facilities have been acquired at Hellyer that can be applied to the assessment of other tailings storage facilities. The application of dredging as a mining method at Hellyer is delivered through collaboration with experts from outside the mining industry under the direction of a mining engineer. Key elements required for the planning and delivery of safe and efficient dredging inside tailings storage facilities have been identified at Hellyer and are presented to provide a road map to the development of other dredging operations.

Sep 1, 2024

By D Stow, M Edmondson

Lemington coal mine is operating in an environmentally sensitive area in the Hunter Valley, NSW, Australia. Late in 1999 the southern pit was developed using a series of box cut blasts. After the initial development the area would have been free dug due to the soft, well-jointed nature of the deposit. However, it was decided to trial drill and blast to determine if shovel productivity could be improved to enable an overall mining cost reduction. The initial trial blast results were less than satisfactory with both environmental issues occurring and the desired shovel productivity not being achieved. An audit of the blasts indicated that wet ground and the presence of soft clay inter-bedded with harder rock caused the poor blast results. Also, water-affected explosive product combined with explosive energy loss into soft ground led to flat spots and tight digging in the hard band areas, resulting in the lower dig rates. Lemington Mine and Orica Explosives developed a plan to match the rock with the appropriate explosive type and energy. This resulted in a number of blasts over a six-month period using a new non fuming explosive product, æNovaliteÆ. The results have been excellent with the environmental issues being totally resolved and dig rates improved, enabling reductions in mining costs. This has allowed the mine to continue with their exemplary record of environmental management whilst achieving operational efficiencies.

Jan 1, 2001

'Nothing happens until something is sold' This statement is not original - it is a necessary orientation for marketing industrial minerals. The most important single philosophy of marketing is that it recognises the consumer as the starting point. Production orientation is concerned with producing products that the customer might buy. Market orientation is concerned with finding the needs of the customer and how they can be satisfied. The difference between the two approaches can be recognised in company structures but the most tangible difference is in the approach by a company to selling and development. In other words, it is the market that decides what can be done with a mineral. The markets requirements dictate what mineral, what grade and what price will be paid. Therefore it follows that when pricing a product we should avoid taking the basic cost and arriving at a final selling price through a series of standard markups (unless government insists on it). We should start with the price the market can stand and work backwards to find out whether you have a profitable product or one that will fail because it is too dear. Naturally a thorough understanding of production costs is necessary particularly when marginal markets are concerned.

Jan 1, 1978

The Taupo Volcanic Zone in New Zealand and the Philippine Mobile Belt in the Philippines are characterized by active subduction, active volcanism and high seismicity. The main factors affecting characteristics of geothermal systems in both countries are: tectonic setting, source magmas, maturity of the systems, and depth to the degassing magma body. Within New Zealand, geothermal systems are grouped into arc- and rift-type. Fluids in arc-type systems contain high amounts of volatiles (40%) and higher Cl contents (3,000-10,000 mg/kg). Maximum temperatures are also higher, reaching up to >400¦C. Arc-type alteration assemblages in New Zealand and the Philippines are similar. Because Philippine geothermal systems are less mature, have higher temperatures and steeper geochemical gradients than New Zealand ones, advanced argillization is more widespread occurring down to depths of 2000 m. Mineral phases are more varied due to the active input of magmatic waters and the formation of vapor conditions at depth, forming P04-, B-, Li-, Ce-, F-, and Cl-bearing minerals at high temperatures. In the Philippines, high temperature magmatic-hydrothermal to contact metamorphic assemblages containing biotite, amphiboles and pyroxenes are relatively common, but rare in New Zealand.

Jan 1, 1995

By I Canbulat, G Si, Y Duan, X Luo

The presence of unfavourable geological structures such as faults and dykes often can contribute to coal burst risk. Seismic events associated with rock fractures tend to cluster around these structures and it is important to understand the characteristics of seismicity for coal burst risk management. In an Australian underground longwall coalmine, two clusters of seismic activities close to the longwall face and within a section of the maingate roadway which was intersected by a major dyke were respectively identified. The induced seismicity in the dyke-roadway area was closely related to the longwall mining. These seismic events were located and the distribution of seismic events shows that more fractures were distributed on the inbye side of the dyke. The spatial-temporal changes of the seismic event locations delineate the fracture propagation as the longwall mined through the dyke. The frequency-magnitude relationship of seismicity was analysed and it was found that it changed significantly when the longwall was mining towards, through and past the dyke. The monitoring results demonstrate that because of the stiff dyke, the seismicity was intensified in the roadway section. It proves that the dyke promoted stress re-distribution and seismicity in its vicinity. More fractures were induced in the hanging wall of the dyke, whereas less strain energy was accumulated and released in the footwall of the dyke.

Nov 29, 2022

By O J. Restrepo Baena, S Nowosad, R Webber-Youngman, N Mojtabai, P Foster, A Binder, S Hazuria, erson, S Raval, L Liu

As the mining industry faces times of change, new challenges arise to ensure raw material supply for the younger and future generations. Different scenarios are currently shaping the way we mine and teach mining engineering. Led by an increasing demand for raw materials, net zero requirements for improving long-term operation performance, technological advancements such as automation and digitalisation, safety improvements, environmental considerations and a need for social acceptance, mining is pursuing to change and adapt to these requirements at a faster pace. Such changing times raise new concerns, one of the most relevant is the lower number of students interested or enrolling in mining engineering and related fields leaving mining engineering as one of the less preferred career options between the younger generations. Nonetheless, it is essential to continue addressing and supplying the skill sets that is suited to contemporary and future of the mining industry. To this end, globally, academia is currently undergoing several initiatives such as curricula updates and adaptation, up skilling, improving teaching practices and techniques, including e-learning techniques, enhancing industry-academia and inter-university collaboration, and much more

Sep 1, 2024

At Hilton Mine, 18 kilometres north of Mount Isa, the silver-lead-zinc sulphide bodies have undergone strong deformation in the form of folding and later faulting and brecciation in the hangingwall region of the mine. Variation in grades and widths over compara- tively short distances causes problems regarding accurate sampling of orebody exposures in underground development, and in defining confidence limits for the extrapolation of ore intersections in ore reserve calculations. The paper gives a preliminary insight into the problem of obtaining representative samples for exposed orebodies and discusses the sampling techniques employed. Results gained from these sampling methods could not be verified due to lack of individual bulk samples for comparison but strong evidence for precision was provided. INTRODUCTION In a developing mine like Hilton, accurate grade information is of extreme importance. Original grade information for a potentially viable ore deposit is gained from surface drilling, and initial ore estimates are calculated from the resultant ore widths and grades. After underground development has proceeded, the opportunity arises for detailed examination of orebody exposures, and the resultant assay grades and widths from sampling of these exposures may, in the long term,

Jan 1, 1976

The title of my presentation is `Nursing One's Resources', words that fit a young organisation like Ross Mining and words we had to apply to reach our current level as a company. To get to where we are, we had to nurse, foster and treat carefully all our available resources in the widest sense of the word, namely: ò a stock or supply that can be drawn upon (funds, mineral resources, human resources); ò the means available to achieve an end; ò skills in devising expedients; and ò practical ingenuity. I do not claim that Ross Mining is now the perfect mining company. However, we have become a profitable, dividend- paying, gold mining and exploration company which is to our knowledge, currently the cheapest gold producer on the Australian continent. Nursing our resources got us where we are and will guide us in our future development. The words `nursing one's resources' are I feel particularly applicable to mining-as I like to argue that the extractive mining industry has a social responsibility to optimise the metal output and value from each orebody which is being exploited, and preferably leave no metal behind. Likewise, a modem company cannot survive into the future without maximising and optimising its human resource potential. In this presentation I would like to present a number of actual examples of nursing one's physical and human resources. Before I do that, I will give a brief background to Ross Mining. Ross Mining NL is a young Queensland-based company that gained its stock exchange listing in September 1987 and that poured its first gold in 1989 from its own developed Belyando Mine, located in Central Queensland. We have now reached the stage of a medium-size gold producer, producing approximately 70 000 ounces of gold per year, mainly from the Yandan Gold Mine, also in Central Queensland. Our production is set to increase to over 100 000 ounces in the near future. Recent increases in our resource base have secured us a future of ten to 15 years. As a young, newly listed company, we faced all the dangers that most new small floats do as a new entrant into an established industry. However, one advantage of being young and perhaps naive, is summed up by the following Zen Buddist saying: In the beginner's mind there are many possibilities, in the expert's mind there are few. A mining company's main assets are the sum of its resource base and the skills and talents of its people. Attempting to optimise both the physical and human resources within the company has been to-date the key to our success. The first example I would like to present is linked to the exploitation of the Belyando Gold Mine in Central Queensland.

Jan 1, 1995

For an exploration area with a predetermined grid of data points, a construction is given for elementary blocks which subdivide the entire area without omission or overlap, and with the property that each data point is situated at the centre of its corresponding block. The construction has a useful optimal property, and more importantly avoids an error which has been made recently in more than one publication.

Jan 1, 1985

By G K. Robinson

Variations in many aspects of physical and chemical grade are often of concern to mining operations and mineral processing plants. In most circumstances these amounts of variation are predictable. At the time of planning new operations, we should be able to predict the amount of sampling and testing variation which our sampling devices, laboratory procedures and on-stream analysis devices will achieve. We should know how well our stockpiles, reclaimers and bins will homogenise material (or whether segregation will actually increase the amount of variation). We should be able to predict the amounts of variation that will occur on the important time or tonnage scales at the crucial p oints in our proposed operation. And once these amounts of variation are reliably known, mine planning will seem a little bit more like dealing with known knowns rather than like dealing with unknown unknowns.The first step towards quantifying amounts of variation for planned operations is to assess amounts of variation for existing operations. How many operations have estimates of amounts of variation in their databases? How often are people able to partition amounts of variation into amounts due to sampling error, amounts due to sample preparation, amounts due to assaying, and the amount of real variation in the stream of material?CITATION:Robinson, G K, 2012. Making sure that the amount of grade variation is a known known, in Proceedings Project Evaluation 2012 , pp 159-162 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

Reduction of Iron Content from Silica by Gravitational Processes In this research work, it was attempted to reduce the iron contents (Fe2O3) in silica sample which was provided from Shenin silica mine using gravitational processes including jig machine, multi gravity separator (MGS), shaking table and spiral. The silica sample contains 93.75 per cent SiO2, 0.44 per cent Fe2O3, 2.78 per cent Al2O3, and 0.08 per cent TiO2 and the Fe2O3 has to be reduced to about 0.1 per cent or less than 0.02 per cent. Mineralogical studies and XRD analysis indicated the presence of haematite, pyrite and goethite as the major iron impurity phases. Mineralogical studies of polished and thin sections yielded that the degree of freedom of silica is more than 80 per cent in the range of -300 +212 mm. After elimination of fine particles, at first nine tests were carried out on crusher product (in two size fractions), wet rod mil product and scrubber product by means of Jig Machine. The best results were obtained with about 0.15 per cent Fe2O3 on rod mill and scrubber product which was not desirable. Thereafter 7 tests were carried out using shaking table; the best results were obtained with about 0.14 per cent Fe2O3 on rod mill and scrubber product which was not desirable. MGS showed the worst result in order to iron removal from silica which was not desirable. Finally 9 testes were carried out using spiral whish is the best gravitational separator for elimination of iron impurities from silica. The best result of spiral tests were achieved on scrubber product. In this test concentrate weight percent and its Fe2O3 grade were 82.32 per cent and 0.085 per cent respectively. Finally a test was carried out using 2 stages of spiral in order to develop flow sheet. In this test concentrate weight percent and its Fe2O3 grade were 78.8 per cent and 0.1 per cent respectively. This product can be used to produce float (clear flat) glass.

Sep 13, 2010

By T Weldon

In the last 15 years, it has become increasingly popular to win gold and silver from carbon strip solutions with electrolytic æsludgeÆ cells. The precious metal sludges produced in the cells are washed to the cell bottom and pumped into filters. Most new operations are specifying sludging cells, and many older operations are being retrofitted with up-to-date electrolytic sludge cells and filters. The new sludging cells are generally more energy efficient than older cells, but more importantly, the cell operations to remove product are much less labour intensive, cleaner, and the operator need not have physical contact with the electrolytically produced metal. A case study of a major North American gold producer (50 000 kg/yr) that removed old style stainless steel wool cathode cells and installed new sludging cells and sludge filters is presented. The effect of various impurities is discussed.

Jan 1, 2005