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The coastline is. an incomparable stretch of sea coast known as Ninety Mile Beach. Two gas pipelines and two oil pipelines carrying hydrocarbons from thb'Bass Strait fields to the markets of Australia cross this beach. They cannot be seen as they are laid in trenching stretch- ing many miles out to sea and the beach was restored to its natural state. Even where the dunes were disturbed, suitable grass was sown thus consolidating the sand and preventing erosion. Ninety Mile Beach is but one of the many key.wildlife and recreational areas that our operations must be concerned with. Others include Westernport and Corner Inlet, but the one discussed in this paper in particular is the platform area of the Bass Strait itself. Never was the old adage "an ounce of prevention is worth a pound of cure" more meaningful than in offshore oil production. All are well aware of some of the events of the past several years that resulted in large and costly oil spills. Far less is known, seen or publicised about the measures and developments that are undertaken to ensure that such events do not occur. We also have well developed plans for response in the event of an emergency situation, which can be initiated with great rapidity. Our responsibility is to ensure that with the best of engineering technology and operating procedures, spills do not occur.

Jan 1, 1971

By Ray H. S, Galgali R. K

It is well accepted that the blast furnace will continue as the main route for iron-making for many more years. However, its limitations have motivated researchers to look for alternative routes, particularly, those where non-coking coal is used for liquid iron production. Smelting reduction (SR), where coal and oxygen are used to produce liquid iron and power is now receiving serious attention. Several smelting reduction reactors are now operating in pilot plant scale and one or two have reached commercial status.

Jan 1, 1999

By McLean E. J

Background The resources of the Gippsland Basin include not only the coal and oil for which it is well known, but also the tourism resource and the quality of life which it offers its residents and visitors. To manage this group of resources requires an understanding and ability to predict the consequences of possible developments. The water of the streams and estuaries as a key component as it is both a resource and the means for transporting wastes from one area to another. To aid in the resource planning process there is a need for models of the estuarine hydraulic processes. This paper describes an appropriate modelling technique. Resource use conflicts may arise from developments in the catchment upstream of the estuarine reach. For example the diversion of water for domestic and industrial use will change the velocity and salinity structure of the downstream estuary. In turn these changes will affect sediment distribution and deposition patterns and may impose stress on the biological communities and ultimately on the fisheries resources and water quality. The manager of an estuarine system may have expertise in ecology, hydraulics or another of the specialist disciplines involved, but commonly will not. The manager will identify needs for resource and development and the broad options required to satisfy them. The manager will use these studies as the basis for his/her selection of the option for execution. Thus a model for'use by the manager of an estuarine system must have the following properties: (i) The model must be sufficiently accurate to throw up all the likely options. (ii) The model must be capable of being run by the manager, interactively, to answer `what if' questions. This requirement implies a simple code andhardware limited to a personal computer or possibly a desk top work station. (iii) The model must be robust so that unrealistic input oes not generate apparently useful output, and no output is generated for cases where the model is not designed to give results. (iv) The model must be capable of being used as part of a modelling system comprising models of all the geographic and demographic components

Jan 1, 1992

Twelve years ago, Jeffrey Mining Machinery Division of Dresser Industries Inc. developed the 120H HELIMINER. This machine was the world's first fixed-drum continuous miner and soon became the standard among manufacturers of continuous miners throughout the mining machinery industry. This paper will first outline a brief history of continuous miner development, then discuss significant parameters which are essential to a successful continuous miner design, and finally describe a number of specific applications of Jeffrey continuous miners in a variety of materials, such as coal, potash, iron ore, and trona, around the world.

Jan 1, 1978

By Woodcock J. T

During the dissolution of gold in fully aerated cyanide solutions the CN ion is the active agent, and consequently the usual method of evaluating the dissolving power of such solutions is to determine the CN- concentration analytically. The presence in the solutions of copper and/or zinc which themselves form complex cyanides, may result in erroneous conclusions as to the free cyanide ion concentration determined by titration.In this paper the theory of titration of such solutions has been developed, and potentiometric methods have been used to follow the behaviour of complex cyanides of copper and zinc. The results for cuprocyanides show Cu (CN)s to be the most important copper complex, and in addition they explain the reported low rates of solution of gold in copperbearing solutions which when titrated in the usual way, appear to have adequate free cyanide. An explanation of the misleading value of the titration is given, and suggestions for recognition of the condition are offered. Preliminary results for zinc-bearing solutions show that there is no satisfactory end-point for the titration of CN- in excess of that in the complex Zn (CN) 4=, which dissociates to CN and Zn(CN)g-.

Jan 1, 1950

By J-P Franzidis

Hydrodynamic conditions such as gas dispersion, mixing intensity and solids suspension are known to govern the metallurgical performance of the flotation process. Understanding flotation cell hydrodynamics is therefore important for the optimisation of existing cells and for the design of the larger and more efficient cells which are needed to handle the finer, lower grade ores currently being mined. This paper presents the results of numerous studies that have been carried out to characterise the hydrodynamic conditions in a number of different types of flotation machines both in Australia and South Africa. Measurement techniques that have been developed to determine gas dispersion and other hydrodynamic properties in industrial flotation cells are described along with applications for their use. The results show distinct differences between the way flotation cells are operated in the two countries.

Jan 1, 2000

By B McCreath

Industrial process water for the Commodore Coal Mine and the adjoining Millmerran Power Station is provided by pumping secondary treated sewage effluent 100 km from the Wetalla Sewage Treatment Plant near Toowoomba. (A separate source is used for potable water.) The effluent is not of sufficient quality for discharge to a watercourse, but it is suitable, with further treatment, for the mine and power station. In designing and constructing the pipeline, special emphasis was placed on preventing accidental spills or planned releases to the environment. The pipeline and associated works can transfer 1000 ML/annum for reuse in the coal mine and power station.

Jan 1, 2003

THE treatment by chlorination of the Mount Morgan Gold Mining Company's ores was first accomplished, early in 1886, by a works having a capacity of 25,000 tons per annum. Shortly afterwards another works was established, capable of dealing with 50,000 tons per annum. The extraction of gold was originally successful and satisfactory, but running expenses were high, averaging £2 19s. 6d. per ton of ore treated. These works were believed to be the largest chlorination pJants in the world at that time. As might have been expected, the mechanical details and chemical process had not been perfected, and, moreover, both works were hurriedly built, and operating expenses were not then considered of such prime importance, as the ore at that time was of very high grade the large quantities of low grade ore since dealt with not being then considered, since the bulk of it was not even known to be in existence.These two works consisted of lock-breakers, high speed rolls, screens, elevators, &c., for crushing; a large number of small handrabbled reverberatory furnaces for roasting; one-ton chlorination barrels and three-ton leaching vats for chlorination.

Jan 1, 1910

By Yaroshenko YuG, Bokovikov BA, Gordon YaM

Problems of the effect of the number of tuyeres and their parameters on the uni- formity of gas distribution are invest- igated with the use of the authors' devel- oped mathematical model of the movement of gases and materials in the blast furnace. It is shown that the improvement of uni- formity of gas distribution with an increase in the number of tuyeres has a damping character. An analysis of the errors of the specified assumptions of the hypothesis concerning the potentiality of the gas movement in the bed is carried out. It is established that the potential approach model gives good results with the determination of the discharge of gas and its stress field, but is not useful for the calculation of local velocities of gas in the raceway. The results of trials of calculation investigations of the dynamics of form- ation of the raceway and the voidageòfield in beds of burden materials are presented in the concluding part of the paper.

Jan 1, 1981

Within the Mt Whaleback open cut mine the integrity of the final pit wall is achieved through careful rock slope design, use of rock reinforecement technology where marginal stability exists and use of controlled blasting techniques and excavation practices. By reducing the effective density of ANFO explosive within blastholes to around 0.2 glcm', and developing standard blast pattern designs for various rock types, blast damage to pit walls has been minimised. Accurate geological prediction is necessary for optimum blast design. Controlled blasting is undertaken where blasting occurs within 90 m of the designed final batter crest and hole by hole assessment of final limit blast patterns is undertaken before pattern charging. Shovels and trucks remove the bulk of blasted and dozed rock material, but due to the mine's variable pit wall slope configuration, bulldozer excavation of some critical design batters has been successfully Implemented.

Jan 1, 1986

Solid EnergyÆs project evaluation process utilises a standard staged gate approach, with five levels leading ultimately to project execution (level 6). For a project to progress through each level, specific financial criteria need to be satisfied. Solid Energy primarily use value based (discounted cash flow) metrics to support investment decisions. Within this approach Solid Energy utilise a number risk-based techniques to quantify project uncertainty. This includes the use of risk-based probabilistic analysis using Monte Carlo simulation and probability-based scenario analysis. Figure 1 shows the net present value (NPV) cumulative probability. Project risks are identified through comprehensive risk workshops. The output of these workshops (list of key risks, ranges of uncertainty and probability of occurrence), is quantified within the financial models. Incorporating this risk information on a probabilistic basis allows an investment decision to be made with a robust knowledge of the range of possible project outcomes along with the likelihood (probability) of those outcomes occurring, for example 80 per cent confidence that the project value will be greater than NZ$10 M, 50 per cent confident it will be greater than NZ$50 M and ten per cent confident it will be greater than NZ$70 M. Incorporating risk implicitly into the financial analysis allows the business to easily evaluate/measure projects with different risk profiles. The detailed risk analysis does away with the complexity of arbitrary risk-based hurdle (discount) rates, as projects can be evaluated based on their specific risk characteristics. Whether a project will progress to the next level of investment and ultimately into implementation depends firstly on the value assessment in comparison with the associated risk/uncertainty, and secondly matching this with the businesses appetite for risk. At Solid Energy standard criteria are used for specific project evaluations, but in addition projects are considered on a portfolio or strategic basis also. Solid Energy attempts to maintain a mix of low risk (low value) projects with some high risk (high value) opportunities. The mix of projects must remain in line with the shareholdersÆ risk appetite. One of the keys to a successful investment decision is ensuring that the appropriate information is available to decision-makers so that they may proceed with a comprehensive understanding of the risks and impacts associated with the decision.

Jan 1, 2007

By Maiman R

One method of forecasting prices of metals is based on analysis of historic relationships between prices, inventories and consumption. The first, but generally overlooked step in this analysis should be to remove from the inventory and consumption figures the effects of seasonal variations. The next step is to construct diagrams which show prices plotted against ratios of inventories to consumption. These diagrams indicate that, when inventories are high, prices show little response to changes in inventories. Below a critical level of inventories, however, the psychology of the market changes and small changes in inventories lead to large moves in prices. The critical level of inventories is termed the "pinch-point"; the diagram which shows prices in relation to ratios of inventories and consumption may be called a "pinch-point diagram".

Jan 1, 1990

Mine closure is a legitimate element of the mining cycle and like mine development involves technical planning, permitting, and finally construction. Closure begins with the mine's operational footprint and transforms the site so that it meets the explicit requirements of the owners and regulators. Implicitly, the closure will increasingly need to meet the requirements of other interested parties such as the local community, workforce, and future land users. Golden Cross is the first modern mine closure in New Zealand. It operated for 6 + years as a mid-size gold and silver mine winning ore from both underground and open pit sources, and processing via a carbon in leach circuit including a cyanide recovery stage prior to tailings disposal. The mine is situated in a sensitive high rainfall environment, and is complicated by the existence of a large ancient landslide underlying most of the tailings dam and waste rock embankment. The regulatory process for mine closure in New Zealand is not clearly understood by operators or regulators alike. The Golden Cross mine was permitted under the Mining Act 1971 and closed primarily under the Resource Management Act. This switch of legislation, the parallel reorganisation of many government departments, and change in societal expectations with respect to long term environmental stewardship during the life of the mine resulted in the requirements of closure being significantly different to the expectations at permitting.

Jan 1, 1999

By C Dell

Hillgrove, situated on the New England plateau of New South Wales, is an area rich in history and resources. Key resources are predominantly antimony, gold and scheelite and the area surrounding the historical field is environmentally sensitive and topographically challenging. Since acquiring the Hillgrove leases, Straits Hillgrove Gold has undertaken a significant exploration program on these historical mining areas with the goal to return the field to production. This exploration program has enabled Straits to significantly increase the resource base and has subsequently enabled the planned redevelopment of Hillgrove to be realised. In October 2006, installation of mining infrastructure and the initial stripping of existing development had commenced. To successfully redevelop Hillgrove, Straits has had to adopt a highly mechanised, trackless, diesel mining operation which will see the production rate commence at an initial rate of 250 kt/a of ore from a narrow vein environment. This ore will be processed on site to produce antimony metal, gold bullion and a scheelite concentrate.

Jan 1, 2008

By Torres F, Cerda I, Gimenez P, Gonzalez G, Castelli L

Slurry density measurement, specially in cyclone feed streams, is fundamental to grinding circuit control. With the purpose of increasing the availability of such a measurement, the design of a soft-sensor in an actual grinding plant is addressed in this paper. The system is designed to substitute the momentary unavailability of the real density sensor, either because it has failed or because it has been removed for any other reason. The ARMAX model structure is determined using the stepwise regression method. Starting with a list of the candidate variables, the method selects, one by one, and in a systematic manner the variables which best model the measurement to be replaced, choosing them from the set of presumably correlated candidate variables. In this paper not only the single measurements are included in the list of candidates, but also combinations of such measurements having physical significance. A phenomenological model has been built with the purpose of determining these combinations. It turned out that in most of the cases the components of combined measurements having physical significance were selected by the stepwise regression method, instead of the single measurements. Actual grinding plant data is used to determine the model structure, to estimate the model parameters and to test the predictive capability of the developed soft-sensors. Good results are shown to be obtained during periods of up to 30 hours of the density soft-sensor operation.

Jan 1, 1995

By D Wiseman, D Weedon, T Akroyd

Models of the size specific processes of particle collision, attachment and detachment have been combined in a form suitable for analysis of a full-scale flotation plant. The model is based on a first principal approach to particle collection by bubbles. Parameters considered include particle size, bubble size, particle contact angle, energy dissipation, entrainment and froth recovery. Using data structures configured within an Excel spreadsheet using æLimn: The Flowsheet ProcessorÆ, the model has been incorporated into a description of the individual cells within a simple roughing and cleaning flotation circuit. Simulated feeds of varying particle size distribution, feed tonnage and varying mineral hydrophobicity representing different mineral phases are presented to the model to produce predicted final concentrate grades and recoveries. Practical techniques for measuring many of the parameters included in the model are now becoming readily available. However, relating the terms included for contact angle, energy dissipation, entrainment (ie water recovery) and froth recovery to measurable parameters in operating plants remain as continuing challenges for research.

Jan 1, 2004

Any future developer of underground mining on the Bendigo goldfield will need to understand the unique geology and gold occurrence of this field. The development and sloping system employed will be primarily designed around these unique features. Modern techniques and equipment used in narrow vein mining will be applicable in this situation.The purpose of this paper is to examine the important geological features of the field as well as the known historical occurrences of the type of gold deposition in the ore bodies. This information will point to a system of development and extraction which will accommodate these features.

Jan 1, 1993

By Cornell J. B

Scaling in Bayer Refineries is a natural consequence of the super-saturated liquors used in the process. The caustic liquor is supersaturated not only with alumina but also silica and calcia at various stages of the process. The basic scaling mechanisms are reviewed and examples of the two basic types, growth and settled scales, are given. Examples include gibbsite scales formed in the precipitators and silica scales formed in heat exchangers. The main factors affecting the rate of growth of growth scales are temperature and supersaturation and are highlighted using a silica scale example. For growth scales chemical cleaning rates can readily be predicted from kinetics and an example for a gibbsite scale is given. For settled scales the growth rate cannot be predicted and the hydrodynamics within the system have most effect. There is no simple method to predict the potential for chemical cleaning of settled scales; some of the relevant issues are discussed, in particular methods to identify the cementing phase in the scale. An example of design considerations for a scaling system, transport of slaked lime, is Given.

Jan 1, 1996

It is a very great privilege for me to be able to address you tonight and I am deeply sensible of the honour which has been done me. I am equally sensible of the inadequacy of my training for the position of President of your Institute.May I say at once what a very great pleasure it is to have so many members from the mainland States visiting us here in Tasmania. We do hope that you will find pleasure and profit in your stay.Since the Annual Conference is always held in the vicinity of one or other of the great mining fields, it has become the practice for the Presidential address to review the history of the particular field and t(j) indicate its place in the economic structure of the country.I propose to follow this practice and to try and present to you a short picture of thÇ mineral industry as it has existed in Tasmania. None of the information is new it is available in diverse and remote geological reports and in publications such as Witham's Western Tasmania and the more recent Peaks of Lyell. The last composite approach was written twenty years ago by P. B. Nye and published as a Geological Survey Bulletin.I have enjoyed preparing this address because on occasion I find it refreshing to look back and see what was known and what was accomplished in the days when the going was a little tougher than it is now, and to speculate upon the reasons that drove men to do what they did. I shall therefore discuss the search for minerals in this State; the discoveries over the years; the elation with which the new fields are greeted; the disappointments attending some of them; the mines that have come and gone; and the...

Jan 1, 1958

Dilution in underground coal operations can be underestimated by up to five times during feasibility studies, with disastrous economic consequences. Every one per cent of stone waste introduced can reduce an in situ specific energy of 25 MJ/kg by some 0.25 MJ/kg and increases the abrasiveness of the run-of-mine coal. Where a wash plant is not in place, penalties imposed for not meeting contractual specifications alone can amount to some $A 1 million per year. This paper presents a method for monitoring, reporting and ultimately controlling dilution in an underground coal mining operation and presents the dilution trends from a continuous miner/longwall mine over an eight year period. The overall dilution level for the mine can be back-calculated by comparing the run-of-mine coal quality to the predicted in situ, undiluted quality. However, this will not identify the actual contaminant types, areas of the mine responsible for the dilution and the reasons for the dilution. This additional information is essential for controlling dilution to acceptable levels. Quality and horizon control using existing sampling information is generally only adequate for longer-term control purposes, and is not suitable for monitoring mining-induced dilution. The cost of close-spaced surface drilling to collect the information necessary for short-term control is prohibitive, particularly for deeper mines. However, much of this data can be collected through underground channel sampling and horizon control measurements taken during continuous miner development and longwall extraction. The mine runs the risk of not meeting contractual quality specifications and of increased equipment wear if this additional information is not available and the sources of dilution cannot be controlled. The information can also be used to plan longwall extraction heights on a short-term scale with resulting improvements in productivity.

Jan 1, 2003