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By M Revell

The paste fill system at BHP CanningtonÆs underground silver-lead-zinc mine is described. The first of its type in Australia, the paste fill system has been operational since December 1997. Key technical and operational learnings since the first underground stope was filled are presented. Issues addressed include plant performance, pipe wear and failure, automatic control, rheology and in situ performance.

Jan 1, 2000

Mary Kathleen Uranium Ltd. recommenced operations in early 1976 following a twelve year period of care and maintenance. Several sections of the plant were modified or completely changed for the second operation. The most important change was the replacement of ion exchange with solvent extraction as the means of purifying and upgrading uranium rich Isolutions Most of the problems experienced in the solvent extraction system originate from the leach liquor which has a strong tendency to form stable emulsions. This has been countered by some careful control of leaching conditions and by closer observation of operations in the solvent extraction area. Most problems have now been resolved and plant recoveries are quite Satisfactory.

Jan 1, 1978

By I Sheppard, A Hills

This paper describes a multi-lift bench stoping method introduced recently to extract the narrow silver-lead-zinc orebodies at the Isa Lead Mine. Cut-and-fill methods were chief mining methods for the narrow orebodies at the mine over 35 years ago. Benching methods were introduced approximately two decades later, and quickly replacing the cut-and-fill methods. The benching methods had improved both the economy scale and safety of the mining operation. The multi-lift benching method combines a number of bench lifts into a single stope to further improve the operational efficiency. Three stopes in the initial multi-lift benching trials are described.

Jan 1, 2003

By Thomas R

The successful `marriage' between a company seeking to raise funds to develop a project and their financiers calls for a strong mutual understanding of each other's needs. For a company attempting to raise funding, the alternative methods are ever expanding. The optimum method will vary depending on the financial position, risk/reward outlook of the company and the strength of the project for which development capital is being sought. It is likely that small mining companies will need to raise equity funds for advancing projects to the development stage. At that time, they will probably still require a reasonable level of shareholder equity to meet the requirements of banks and other parties to cover potential cost over-runs on the project and feasibility costs. Larger companies, however, are likely to find it much easier and cheaper to raise debt from banks. When evaluating companies and projects for funding, banks will pay particular attention to the quality and experience of management in developing similar projects and it may be necessary for some companies to retain the services of outside consultants. Before a project needs funding, companies should meet with potential financiers to develop relationships to select and ensure a smooth transaction to funding in the future.

Jan 1, 1997

By Moorrees C, Koh P. T L, Tsambourakis G

Examination of Ihe calcination and carbonic acid leaching behaviour of a number of Australian magnesites shows that there are substantial differences between the massively crystalline and the cryptocrystalline forms of magnesites. Crude magnesias formed by calcination of the massive variety of magnesite have considerably smaller surface area and show lower rates of reaction with carbonic acid when compared With those derived from cryptocrystalline magnesites. In order lO producc a rcactivc magncsia from massive magnesite, the calcination conditions must be carefully controlled over a narrow temperature range (eg 680-720°C). For the cryptocrystalline calcines, the temperature of formation has little effect on reactivity.The results confirm the general applicability of the calcination/carbonic acid leach process for producing magnesia from magnesitc. If a mixed crystalline/cryplocrystalline feed is to be processed, then processing conditions must be optimized in terms of the behaviour of the crystalline component of the feed.

Jan 1, 1985

By Rosentreter N

Difficulties with froth flotation recovery and vacuum de- watering equipment for the treatment of fine coal have been investigated. Mechanical alterations to cyclone desliming banks, and flotation cells are described. A large disc filter has been replaced by two drum filters for dewatering, and the improvement in plant. operation is discussed:

Jan 1, 1978

The phrase "Total-Energy" has, during the past few years, become widely used to describe a wide range of very different operations. However, if accurately described they all have one basic factor in common - energy usage is optimised with the prime mover being powered by gas or oil to generate shaft horsepower and the products of combustion being put to some use. The item which distinguishes a Total Energy system from any other engine or turbine driven project is that orate pains are taken to utilize the waste heat, whether this be in the form of exhaust gases and/or engine jacket ling water. n areas where grid supplies of electricity are readily available, the economics of most projects undoubtedly hinge upon the successful application of waste heat. However, there has been a growing awareness of other benefits, such as reliability of supply, which can be incorporated into the system. In particular these factors sway managements of hospitals and companies with complex computer facilities to examine closely the feasibility of Total Energy, Consequently, in America for example, where many systems have proved themselves the list of applications is wide - shopping centres, apartment blocks, office buildings, airline terminals, universities, schools, motels. And these do not cover the industrial sectors where the range is wider. The total number in North America is now approximately 500 and this to some extent-speaks for itself. In Australia, the real work involved in carrying out feasibility studies for Total Energy is only just beginning. 'in some quarters, the concept is not well received in that it is too new. Therefore, a typical approach is to play safe and wait until some other company has proved its operation "under Australian conditions". This is certainly a realistic approach when considering something revolutionary but as far as Total Energy.is"concerned all the individual components and sometimes combinations, (engines, generators, boilers, air-conditioning units) have been in operation for many years. The only innovation is that they are now all being brought together under one roof. This should not be forgotten when the question "where can I see something like this operating?" is asked.

Jan 1, 1970

Following GyÆs earlier proposals for the use of StudentÆs t-test, a simplified, effective method and philosophy are proposed to test for maximum tolerable bias in data sets as well as in sampling devices. The philosophy of testing is particularly emphasised to derive important practical implications in terms of decision-making and risk control. Conclusions are offered which should equally matter to manufacturers and users of sampling equipment.

Jan 1, 2005

A wide range of models are available to computer process simulators that require a large number of parameters which often are physical measurements, coefficients, calibration factors and functional forms. This makes it intuitively difficult in the majority of cases, to tune the parameters in order to simulate a circuit in agreement with experimental results. Unit calibrators operating on the principle of least squares minimisation of the difference between predicted and observed plant data, are relatively successful when the parameters are unconstrained and independent of each other. In the case of constrained parameters, a set of carefully chosen transforms is presented which map the unconstrained variables being minimised into the constrained parameters required for the model. This technique has been used successfully with the Powell minimisation algorithm and it may also be applied to other unconstrained minimisation methods. Necessary model characteristics are discussed to enable these transforms to be applied to interdependent model parameters such as points of a graph. Examples of the calibration of several unit models using these transforms are presented. KEYWORDS: Calibration, optimisation, transforms, process simulation.

Jan 1, 1993

A/method of introducing nitrogen into alloy steels using iron and ferromanganese nitrides is considered. Data are I ded on the nitrides produced. The kinetics of the formation of the'nitride product from the reaction between or ferromanganese powder and ammonia are presented, together with an indication of the efficiency of the Reactions.

Jan 1, 1970

Synthetic hollow microspheres have demonstrated reliable sensitization and detonation characteristics in industrial explosives for almost two decades. During that time, water gel formulations and use conditions have changed. The introduction of emulsion explosives has also dictated technical improvements in microsphere sensitizers. In contrast to microspheres, gassing or other sensitizing techniques often cannot satisfy the manufacturing and blasting characteristics required of today's explosives. This paper discusses the sensitizing properties of microspheres, formulating guidelines and quality considerations. Packaging, sampling, transfer, metering, mixing and pumping information is also provided.

Jan 1, 1990

By Khosrowshahi

A scientific approach to analysing grade control has been applied at a number of mining operations. By dividing the grade control process into the various stages of data collection and interpretation, errors can be identified using reconciliations of production against predictions. The merits of different mining styles in large and small open pit mines are examined.One factor in successful grade control is estimation of the expected ore loss and dilution. Empirical methods developed in two dimensions have been refined to enable 3D modelling of the effects on mineable grade and tonnage of varying the bench height, sampling orientation, and sampling Resolution.

Jan 1, 1992

By S Choy

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

Jan 1, 2003

In making any attempts to determine the depositional environments in which coal seams accumulated it would be useful to establish whether there is a pattern, or patterns, of development which the majority of the seams have followed. To this end, the distribution of types of coal seam sequences found in the standard petrographic profiles of about a hundred Australian coal seams of Permian and Triassic age has been examined statistically, using the "chi square test" with the limiting probability set at O·Gl.Results indicate that non-random conditions have probably prevailed during the deposition of most of the seams. More samples are needed for conclusive results.The plants, or some other internal feature of the swamp environment, have been the important controlling factor in the development of the seam sequences.Comparison has been made with some British Carboniferous coals.

Jan 1, 1972

By K Ellis, K Quast, R Newell

The use of ammonia as a leaching agent in the recovery of copper from ores and concentrates has a number of potential benefits. These include the ability to treat ores with an acid consuming gangue, non-corrosivity, the insolubility of iron in the solution and increased selectivity. This paper reviews the previous and current use of ammonia based leaching systems for copper recovery and presents the results of a laboratory investigation that involved leaching of a copper concentrate and a low-grade ore. The effects of the operating variables (particle size, oxygen addition, agitation and temperature) are discussed. Of these, the particle size had the greatest effect, with decreasing size giving improved leaching rates and recoveries. The possibility of using ammonium salts in heap leaching is also discussed, and the results of some small-scale column leach tests presented. Possible methods for recovering the copper from the leach solution are outlined, and the types of ores and concentrates for which ammonia leaching may prove to be a viable alternative processing route are discussed.

Jan 1, 2000

In July 1994 the Premier, John Fahey MP, announced that the New South Wales Government would make available a total of $40 million over six years in new funding for the Department of Mineral Resources. These funds are to be applied directly to the generation of regional geological and geophysical information. The Government's initiative known as `Discovery 2000', is aimed at providing a major boost to the exploration industry. The Government expects new discoveries to be made and new mines to be developed because of the initiative and, perhaps, the first ever commercial oil or gas production in New South Wales. The Government's return will come from increased economic activity, and from the increased royalty return from higher levels of production. Quality information is the key to successful exploration. In the highly competitive business of mineral and petroleum exploration high quality regional geological and geophysical information improve both the efficiency and effectiveness of the area selection or project generation process. Using the `needle in the hay stack' analogy, Discovery 2000 will vastly improve industry's chances of finding the haystacks. It is up to the mineral and petroleum industries to find their respective `needles'. Careful target area selection is probably the most critical factor in mineral exploration. The ability to select the most prospective areas, or to identify prospectivity that others have failed to recognise, can make all the difference between success and failure. Government geological surveys clearly have a crucial role to play in providing the geoscientific information infrastructure that companies must have if they are to make the discoveries this country needs to pay its way in the world. It is the regional information generated by Governments that sets the scene for efficient exploration. This regional information includes regional aeromagnetics and radiometrics and gravity, regional geological mapping and tectonic analysis, and geoscientific databases. The New South Wales Department of Mineral Resources (by various names) has been providing such information for over 100 years and has led the way in many aspects of the generation and dissemination of geological, geophysical and metallogenic Information.

Jan 1, 1995

Diesel-engine exhaust emissions represent a concern to the mining industry due to the poten- tially harmful health effects of the pollutants, as well as high costs associated with providing proper ventilation to assure a healthful working environment. The control of exhaust emissions is complex since the operating mode and condi- tion of the engine, the mine environment, and the operator's skills all influence the concen- tration and composition of the emissions. It is not practical to measure each exhaust pollutant in underground mines; therefore, a monitoring methodology is required to measure the pollut- ants and assess the air quality.

Jan 1, 1988

By Bojcevski D

The deportment and textural relationships of silver bearing phases are key characteristics in understanding the behaviour of silver ores in flotation tests or processing plants. These characteristics are however difficult to define and quantif

Jan 1, 1997

By Davey KJ

Complex sulphide ores are characterised by complex texture of the valuable minerals. Any assessment of the performance of differential flotation circuits treating such ore should include analysis of the effects of poor liberation of the valuable minerals. Selected samples were taken from balanced size by size surveys of the flotation section of a concentrator treating an ore body containing fine grained galena and sphalerite in a matrix of iron sulphides which is mostly pyrite. liberation measurements were made using the QEM*SEM system on four or seven size fractions. The measurements indicated that less than 40 per cent of the galena and less than 60 per cent of the sphalerite in the flotation feed was liberated. The final concentrates were largely composed of composites of valuable minerals and iron sulphide however there was a small but significant fraction of liberated iron sulphide. Using the sized mineral flows obtained from the original balances and the liberation measurements, a satisfactory liberation balance was obtained. This enabled the effect of liberation on the flotation performance to be examined; not only for the entire circuit but also in the rougher, scavenger and cleaning sections. In the zinc circuit the effect of a regrind mill could be assessed. Recovery of galena in the lead circuit was limited by the recovery of composite lead particles. Recovery of liberated galena exceeded 95 per cent in all size fractions while the recovery of composite galena exceeded 85 per cent below 38 ¦m but fell sharply above 38 ¦m. Examination of the behaviour of the liberated and composite galena in the various sections of the lead flotation circuit revealed high recoveries of both liberated and composite galena particles in the roughing and scavenging sections but very low recoveries in the final two cleaning stages. Similar trends to those observed in the lead circuit applied in the zinc circuit although the performance of the liberated sphalerite also fell off at sizes greater than 38 pm in this case. Thus the zinc recovery was limited by the flotation of both the liberated and the composite sphalerite. The effect of regrinding was to increase the recovery of sphalerite mainly by reducing the amounts of sphalerite in less liberated sizes rather than by increasing the liberation of the sphalerite within a given size Fraction.

Jan 1, 1993

A Modelling Approach Using a Back-Calculated Induction Time to Predict Recoveries in Flotation

Sep 13, 2010