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By M D. Raine, J K. Bartlett, S C. Dominy

The Bendigo Goldfield is located in the state of Victoria, Australia, and is one of a number of fields that make up the Central Victorian Goldfield. Since 1993, Bendigo Mining NL has been carrying out an extensive re-evaluation of the goldfield and is currently well advanced in developing an underground mine. The sediment-hosted auriferous quartz reefs are structurally complex and closely associated with anticlinal axes and reverse faulting. The gold within the quartz reefs is characterised by both its coarse nature (100 up to >5000 ¦m) and its erratic distribution; as a result, the Bendigo Goldfield is classed as an extreme nugget effect system. This characteristic ensures that the Bendigo mineralisation is very challenging to sample and evaluate. In this case, diamond drilling is a good measure of structure and geological continuity, but a poor measure of grade and grade distribution. Drilling, combined with on-reef development, bulk sampling and detailed geological studies are required for resource evaluation. For grade control a balance has to be sought between sample representativness, cost, turn around time and practicality. Extreme nugget effect deposits like Bendigo, require the use of bulk samples in order to be representative. However, the cost and turn around time is significant. As a result, a micro-bulk sampling system has been introduced that attempts to overcome these problems by providing a fast, practical method that can define ore from waste. Bulk sampling and on-vein development are still necessary for resource and reserve estimation.

Jan 1, 2003

By Nixon J

Open pit mining began in 1978 at the Woodlawn base metals deposit. For its ten years as an open pit the mine was financially unsuccessful as a combined result of difficult metallurgy and industrial unrest. In 1985 CRA bought out two American joint venturers with a view to going underground and a prerequisite to expending capital on developing an underground operation was to improve the industrial climate, work practices and mining methods.Following feasibility work, continuous production from the underground mine began in 1986 using mechanised cut and fill methods and a workforce trained under a multiskilling program. Men with no previous underground experience were trained by supervisors with backgrounds as miners to undertake all the work that is required with increases in skill levels being rewarded with increases in pay.

Jan 1, 1992

By Hirose K, Itakura K

A new global stiffness matrix evaluates the performance of powered supports by estimating and comparing the global stiffness matrices of ten different types of powered supports with lemniscate linkages, each support having its own deformation characteristics. Expanding the global stiffness matrix allows the implementation of a finite element scheme to analyse the interaction between the powered support and the strata around the coal face.The evaluation of performance by the stiffness matrix method shows that 4-leg chock shields possess both the desirable convergence and shear deformation stiffness properties. The finite element analysis also confirms that 4-leg chock shields present well balanced performance for controlling strata around the coal face.

Jan 1, 1991

By Beeforth C. G

The use of Non-Linear Programming to obtain improved schedules of future activity in two specific cases of mining and treatment of minerals is described. The two cases were (i) reclamation of gold, uranium and sulphur from old surface tailings dams and, (ii) underground mining of gold. The method used an augmented Lagrangian device to reduce a constrained Non-Linear Programme to a sequence of unconstrained hill- climbing procedures. The main advantages of the method appear to be those of (a)flexibility of modelling of industrial characteristics and constraints and, (b) reasonably modest computation times.

Jan 1, 1977

Mining companies in order to compete and succeed in being viable business propositions must look to the future and select mining methods which guarantee improved efficiency and productivity as well as lower costs.A mining company in adopting a method of mining must now select the equipment most compatible. To some mines compatible equipment may mean the use of drilling jumbos to replace hand held rock drills or the use of load haul dump units to replace scrapers. To other more mechanized mines compatible equipment may mean the use of raise borers and road heading machines. The right decision will be where equipment compliments method in such a way that the working environment is improved, productivity is maximized, cost if reduced and all profit opportunities are optimized. An example of such is where the use of improved mining techniques in underground operations may see cut off grades reduced. By selectively mining these lower grade orebodies, smaller operation's ore reserves improve and the capacity for continued growth is enhanced.

Jan 1, 1990

By C M. Côte, P Bolz, R Chrystal

The design of final landforms is an integral part of mine closure plans in Queensland and aims to ensure the rehabilitated land is safe, stable and non-polluting. Landform stability in this context is commonly assessed using Landscape Evolutions Models (LEM) which are physical models simulating sediment erosion and deposition around individual landforms over long timespans (up to thousands of years). The most used LEM for assessment of rehabilitated landforms in Queensland is SIBERIA (Willgoose, Bras and Rodriguez-Iturbe, 1991; Tucker and Hancock, 2010). SIBERIA models are complex, require very detailed input data and simulate erosion and deposition over time frames that extend decades beyond closure. They are not suitable to assess erosion risks during the operational phase of a mine and to support the development of erosion and sediment control plans. Other types of erosion models, such as the Revised Universal Soil Loss Equation (RUSLE, Wischmeier and Smith, 1978) or Water Erosion Prediction Project (WEPP, Nearing et al, 1989) calculate soil loss on a monthly or yearly basis and are much better suited to erosion management during the operational phase. They are simpler to implement and can support the design of control measures. For instance, designing a sediment basin requires quantification of sediment loads, which can be produced by these models. In Queensland, the legislation around sediment and erosion control for open cut mines is currently tightening. Soil erosion remains a major concern due to potential impacts on the receiving environment. It requires management during operation and for closure consideration alike and it is critical that erosion and sediment control plans are developed with the most appropriate tools. Globally, RUSLE is the most widely used soil loss model (Borrelli et al, 2021). This is because it is an empirical model with relatively simple input requirements: biophysical data such as soil properties, vegetation cover, topography and rainfall variability, which can be directly measured or derived from regional or national databases and/or spatial data sets that are available in most parts of the world. The second most used model is WEPP (Borrelli et al, 2021) but compared to RUSLE, there is a large drop in the frequency of its use. This is because WEPP is physically-based and has more complex data requirements. WEPP integrates hydrology, hydraulics, erosion mechanics and land cover to predict soil erosion and sediment transport on hill slope profiles and small watersheds (Stolpe, 2005). It requires some biophysical parameters in formats different from those of RUSLE, as well as detailed hydrologic and catchment data. Nevertheless, it has been used in landform design for mines across Australia to determine final landform stability (eg Howard and Roddy, 2012; Costin, 2020). In this study, we assess which tool would be the most appropriate to support development of erosion and sediment control plans from operation to closure. We use RUSLE and WEPP to predict soil loss from a mine site, compare the results from both models and outline the advantages of each method.

Aug 2, 2023

Using normal low pressure filtration methods for the dewatering of fine china clays, the best that can be achieved is cakes with about 30% moisture. In order to get the moisture levels down to acceptable levels the traditional method used is thermal drying, which is both costly and dust creating. It was to improve this process that ECC International embarked upon a programme of development of filtration equipment using high pressure to achieve significantly lower moisture levels. This development work investigated several design philosophies and culminated in the production of two quite different solutions. The High Pressure Plate Press uses round plates / chambers of one metre diameter and a filtration pressure of 70 bar. This press is fully automatic and produces a surface dry cake that has sufficient plasticity for the further processing that is required on specific qualities of china clay. The TUBE PRESS on the other hand uses a unique design configuration and operates at a filtration pressure of 100 or 140 bar, depending upon the model. The TUBE PRESS produces a brittle, surface dry cake that is easy to handle and a filtrate that is usually crystal clear. The TUBE PRESS achieves a much higher degree of separation than is possible with conventional equipment, which is particularly important if the filtrate is the product. Over the past 15 years plants incorporating both HP Plate Presses and TUBE PRESSES have been installed in the china clay operations of ECC International and are giving excellent trouble free service. The TUBE PRESS has also proved to be extremely versatile, effectively dewatering a wide range of fine particled slurries, in a number of diverse industries.

Jan 1, 1989

By B Cope, N Hastings, D Webb

A Feasibility Study was completed in late 2002 to ascertain the risk and reward profile from the proposed deepening of operations at Perseverance Nickel Mine in Western Australia. The system and approach adopted to this brownfields extension work is outlined and the main components of the study are overviewed. In particular, emphasis is given to the integration of mine design and scheduling tools through to financial evaluation. Detailed comment is given on the ability of the system used to provide a robust project schedule complete with 3D animation. The level of importance in eliminating scheduling errors is demonstrated in relation to the reported bottom line viability of the project. It is suggested that this is an area where brownfields Feasibility Studies have lacked clarity and authenticity, leading to the creation of an unrealistic benchmark for project implementation.

Jan 1, 2003

By Cutafani M, Lama R

An approach to combatting abnormal roof control conditions in underground coal mines is outlined. Support techniques available are discussed along with the methods available to be adopted in different situations. Properties of materials available presently are tabulated together with the conditions of their Application.

Jan 1, 1988

By Allchurch P. D

At Perseverance a reserve of 45 million tonnes at 2% Ni was indicated by drilling. Holes were drilled in trellis pattern on section lines 61m apart to assess shallow mineralization. To explore at depth holes were spaced 122m apart, collared vertically, then allowed to deflect under controlled drilling conditions. The mineralization may be divided into the three homogeneous classes of soarsely disseminated, heavily dissem- inated and massive sulphides. In the standardised sampling and assaying procedures used to assess the deposit, attention was always paid to these fundamental ore types. All sampling and assaying processes were continuously monitored by checks. Sampling and sample preparation errors were small, to judge from the differences between results of original and check samples. Assaying errors, determined from analyses made by independent laboratories using different methods, slightly exceeded sampling errors. Comparison of underground core, c'iannel, and grab sampling, suggests that core sampling tends to undervalue.

Jan 1, 1976

By D P. Telionis, P P. Vlachos, R-H Yoon

Industrial processes involving multi-phase flows such as flotation require understanding of the relationships between bubbles, solid particles and the flow. Modern experimental tools are employed in this effort to measure with great accuracy the basic features of the motion of all three phases in turbulent flow. We employed a unique digital particle image velocimeter (DPIV) that can record with great accuracy and kHz temporal resolution, velocity vectors of all three phases, namely the fluid, the solid particles and the air bubbles. The interaction of these three phases was studied in homogeneous isotropic turbulence generated by cylindrical grids. Particles and bubbles were released into the turbulence and the motions of the three phases were monitored. The experimental results obtained in the present work were compared with the predictions of the models published in the literature.

Jan 1, 2005

By McDonald K. J, Flann R. C

A liquid phase sintering (LPS) process for preparing basket anodes from nickel powder has been scaled-up and the innuence of compact green density and sulphur content, as well as sintering conditions (period and syngas now.rate) on the perfonnance of anodes has been evaluated. The product anodes have been tested in an industrial electroplating tank. It is concluded that if anode residues are to be minimised, then with a sintering temperature of 960"C, compact green density needs to be as high as economically achievable (85 - 87 per cent density of solid nickel) and the sintering period approximately 40 minutes. With these constraints, if residual sulphur contents of anodes are to be kept as low as those of commercial anodes, then the sulphur content of the green compacts would need to be less than 1670 ppm. At the same time, it is also found that residual sulphur concentrations as high as 2000 ppm are beneficial to anode pcrfonnancc and not detrimental to the quality of the electroplate. The ability of the LPS process to produce marketable nickel anodes for the electroplating industry is clearly demonstrated.

Jan 1, 1993

In the past ten years or so there has been a renewed interest worldwide in the processing of refractory gold ores. The Archean province of Western Australia contains both numerous and major gold deposits, and has a long history in the development and practise of treating refractory ores (eg Blaskett and Woodcock, 1953). Depletion of shallow oxidised ores in recent years has re-focused attention on deeper sulphidic ores, and as a consequence has renewed interest in treatment methods for those ores which are refractory. Mineralogical factors he at the heart of reasons as to why these ores are refractory, and are the key to designing and improving treatment options in the longer term. This paper presents an overview of mineralogical factors that are relevant to the processing of refractory gold ores in the Archean of Western Australia. It is based on a number of research projects and other work on a variety of gold deposits, mainly in the Eastern Goldfields region, carried out over the past five years or so.

Jan 1, 1991

The South Comet mine is an underground silver-lead-zinc mine located on the West Coast of Tasmania with an annual production in the order of 35 000 tonne per year. All ore mined is shipped to the Rosebery mill by road, a distance of 17 km.

Jan 1, 1993

By Swift J. D

A key parameter affecting the performance of gravity thickeners in hydrometallurgical processing operations is the aggregation state of the feed after the addition of a flocculant. New procedures which measure the settling ratelsize relationship and the size distribution of aggregates in their process liquors have been used to quantify the aggregation state of the feedwell, overflow and underflow streams in a tailings thickener. The data obtained have been related to the thickener's operation and to a change in the flocculant dosage. A comparison is also made between the settling rate/size relationships determined with these new procedures and the mud-line settling rates from cylinder tests.

Jan 1, 1991

The first grant of land rights in Australia was pursuant to the Aboriginal Land Rights (Northern Territory) Act 1976. That Act has been at the core of the dispute between land rights and miners' rights. The mining industry believes that the Act, in giving a right of veto to Aborigines with respect to exploration and mining on Aboriginal land, has been responsible for a stagnation in exploration amd mining activity in the Northern Territory. In February 1985 the Commonwealth Government released for public comment its preferred model for national land rights legislation. The model has been opposed by the mining industry because it believes, first, that land rights is a matter which should be left to the States and, secondly, that the detailed mechanisms contained in the model constrain the industry in the manner of the Northern Territory legislation. Aboriginal leaders have opposed the model because it does not, in their view, measure up to undertakings given by the Commonwealth Government and, in addition, it provides for amendments to the Northern Territory legislation which are likely to result in the loss of the Aboriginal veto right. Are land rights and miner's rights compatible? The answer is yes provided all parties, including Governments, are prepared to talk and compromise and Governments recognise that the grant of land rights and any control by the Aboriginal people of exploration and mining on their land is not a substitute for raising the living standards of Aborigines as a significant group of disadvantaged Australians.

Jan 1, 1986

Caving is the lowest cost underground mining method, provided that drawpoint spacing, drawpoint size and ore handling facilities are designed to suit the caved material and that the drawpoint horizon can be maintained for the draw life. In the near future several open pit mines that produce in excess of 50 000 tons per day will have to examine the feasibility of converting to low cost, large scale underground operations. Several other large scale, low grade underground operations will experience major changes in their mining environments as large dropdowns are implemented. These changes demand a more realistic approach to mine planning than has occurred in the past, where existing operations have been projected to increased depths with little consideration of the change in mining environment that will occur. As economics force the consideration of underground mining of large, competent orebodies by low cost methods, the role of cave mining will have to be defined. In the past caving has generally been considered for rock masses that cave and fragment readily. The ability to define cavability and fragmentation, the availability of large, robust LHDs, a better understanding of draw control requirements, improved drilling equipment for secondary blasting and reliable cost data have shown that competent orebodies with coarse fragmentation can be exploited by cave mining at a much lower cost than with drill and blast Methods.

Jan 1, 1995

Previous methods for the assessment of the explosive potential of gas mixtures have required the plotting of apeexplosibility diagram. These became cumbersome if a large -number of assessments of various sampling locations over a period of time wererequired. This may make the approach of a dangerous situation more difficult to predict. With the aid of a programmable calculator, a new method for the rapid assessment of the explosibility of coal mine sample gases has been developed. This method does not require that an explosibility diagram be drawn to indicate the explosive status of a gas mixture. Simple Cartesian co-ordinates representing the explosive potential of,mixtures are obtained, which may readily be plotted to show changes with time.

Jan 1, 1981

By D J. Williams, M S. Zbik, A Shokouhi

There is a considerable difference in the particle size distribution (PSD) of clay mineral-rich coarse coal reject with variations in the test moisture state and the chemistry of the water used for testing. The coarse coal reject tested were collected from Jeebropilly Mine, located in the Ipswich Coalfields of south-eastern Queensland. Differences between the results of dry and wet sieving analysis indicate a significant breakdown of the clay mineral-rich coarse coal reject on wetting-up. Wet sieving caused a breakdown of the gravel-sized fraction to silt and clay size without significant breakdown to sand size. There is also a considerable variation in the results of hydrometer analyses of the clay mineral-rich coarse coal reject with variations in the chemistry of the water used, particularly at the fine end of the particle size range. The waters used included tap water, coal processing water and deionised water. In addition, the method of dispersion applied prior to hydrometer analysis can have a significant effect on the PSD of clay mineral-rich coarse coal reject, with boiling and sonic vibration causing the most breakdown of the clay particles. This paper describes the testing methodology used and the test results obtained, and attempts to explain the results in terms of clay mineralogy and water chemistry.CITATION:Shokouhi, A, Williams, D J and Zbik, M S, 2015. Influence of water on particle size distribution of clay mineral-rich coarse coal reject, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 239–246 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By Royston, Woods R

ANI Bradken Vortex Pulp Lifters and Grates, both as original equipment and retrofitted to existing SAG mills, are now in field operation. The development of the Vortex leading curve pulp lifter was based on an analysis of traditional radia

Jan 1, 1997