Search Documents

The Income Tax Assessment Act ["the Act"] levies tax on a taxpayer's taxable income. At a time when commerce and life were more simple, the calculation of taxable income had some connection with logic and a taxpayer's capacity to pay. However, as a result of successive governments' different views of equity, their perception of avoidance, their needs for revenue and their changing views on capacity to pay, the rules determining the calculation of taxable income have continually changed to the point that logic is no longer relevant. Taxable income now is simply the product of the application of a complex set of rules.

Jan 1, 1990

By Keren Z, Huanguo G, Jlchuan Q

In this paper, the authors introduce a new flotation technique, a double collection flotation precess, which succeeds in separating feldspar from quartz effectively in weak acidic medium (pH = 5-6). In the presence of sodium hexametaphosphase(HMP), sodium oleate selectively improves the floatability of feldspar in the first collection step. Dodecyl amine- hydrochloride is used as collector in the second collection step to separate feldspar from quartz. The flotation tests with pure minerals as well as artificial mixture give out satisfactory results. The mechanism of reagent effect was investigated briefly, which is helpful for understanding the Process.

Jan 1, 1993

An efficient energy management programme can often significantly reduce a company's energy costs. The programme consists of a series of steps, namely a statement of support from senior management, assigning the management team, the energy audit, defining the goals and comwnicating with and training employees. The energy audit provides the information base from which the company can start to control and improve upon energy Usage.

Jan 1, 1983

By Canterford JH, Ritcey GM

With the development of new technology and materials of construction, chloride-based hydrometallurgical routes have gained accept- ance as a viable alternative to sulphate-based routes. A number of commercial and pilot plants built and operated over the last decade have provided invaluable experience and con- fidence in their use. Chloride hydrometal- lurgy, with or without pyrometallurgical pre- treatment, is particularly attractive for pro- cessing complex Cu/Pb/Zn/Ag concentrates, nickel mattes and chalcopyrite concentrates. This review outlines recent developments, dis- cusses advantages, as well as indicating some of the problems still to be solved.

Jan 1, 1984

By Kyle J. H, Misra V. N

The most recent development in gold processing is the increasing use of heap leaching for the extraction of gold from low grade ore, and old tailings dumps. The reason for this trend is mainly to do with economics. The advantage of heap leaching is the considerable saving in both capital and operating costs. However, not all ores are amenable to heap leaching. It is only applicable to well oxidized ores that have suitable permeability char- acteristics, and the gold recovery is poorer than by conventional process. In this study, an attempt has ben made to ascertain the heap leaching characteristics of Western Australian gold ores on the bench scale using multiple, appropriately sized leach columns. The influence of particle size, flow rate, column depth and leaching time on the rate of gold extraction was determined. The percolation rate of cyanide leaching solution was deter- mined with and without gypsum additions. Efforts were also made to minimise particle segregation, fines migration and solution channelling during leaching, so as to improve solution percolation, gold extraction rate and recovery.

Jan 1, 1991

By I Brunton

Blast fragmentation can have a significant impact on the profitability of a mine. An optimum run of mine (ROM) size distribution is required to maximise the performance of downstream processes. If this fragmentation size distribution can be modelled and controlled, the operation will have made a significant advancement towards improving its performance. Blast fragmentation modelling is an important step in Mine to MillTM optimisation. It allows the estimation of blast fragmentation distributions for a number of different rock mass, blast geometry, and explosive parameters. These distributions can then be modelled in downstream mining and milling processes to determine the optimum blast design. When a blast hole is detonated rock breakage occurs in two different stress regions û compressive and tensile. In the first region, compressive stress waves form a æcrushed zoneÆ directly adjacent to the blast hole. The second region, termed the æcracked zoneÆ, occurs outside the crush one. The widely used Kuz-Ram model does not recognise these two blast regions. In the Kuz-Ram model the mean fragment size from the blast is approximated and is then used to estimate the remaining size distribution. Experience has shown that this model predicts the coarse end reasonably accurately, but it can significantly underestimate the amount of fines generated. As part of the Australian Mineral Industries Research Association (AMIRA) P483A Mine to MillTM project, the Two-Component Model (TCM) and Crush Zone Model (CZM), developed by the Julius Kruttschnitt Mineral Research Centre (JKMRC), were compared and evaluated to measured ROM fragmentation distributions. An important criteria for this comparison was the variation of model results from measured ROM in the fine to intermediate section (1 mm to 100 mm) of the fragmentation curve. This region of the distribution is important for Mine to MillTM optimisation. The comparison of modelled and Split ROM fragmentation distributions has been conducted in harder ores (UCS greater than 80 MPa). Further work involves modelling softer ores. The comparisons will be continued with future site surveys to increase confidence in the comparison of the CZM and TCM to Split results. Stochastic fragmentation modelling will then be conducted to take into account variation of input parameters. A window of possible fragmentation distributions can be compared to those obtained by Split. Following this work, an improved fragmentation model will be developed in response to these findings.

Jan 1, 2001

By D Reid

Many of the relevant engineering behaviours of tailings are controlled to a large degree by the density of the material. For example, loose tailings are prone to brittle strength loss, while dense tailings are dilative (i.e. gain strength) at large shear strains. The critical state framework has been successfully developed over the past few decades to assess whether in situ conditions are contractive or dilative, and estimate relevant engineering parameters on that basis. Tailings comprising primarily silt-sized particles, when subaqueously deposited, often form a particularly loose state compared to subaerially deposited material of similar index properties. Such subaqueous deposition occurs in the decant pond area, where the tailings typically pluviate in quiescent conditions within a pond of standing water. Silt tailings deposited in such a manner have been observed to be extremely loose in a number of TSF investigations. Of particular concern, the deposited material in such cases appear to be significantly looser than can be reproduced in the laboratory - even using moist tamping, the sample preparation method which can usually produce the loosest samples possible in laboratory conditions. While the loose density of subaqueously deposited silt tailings is clear, in a well-managed upstream-raised TSF the decant pond is usually small and far from the perimeter embankments, however there are a number of examples where the engineering performance of such materials becomes relevant – for example, when historical deposition practices were poor, resulting in subaqueous deposition near the perimeter embankment. This paper outlines the geotechnical characterisation of a number of such subaqueously-deposited zones, compares the in situ state to that achievable in the laboratory, and discusses options for assessing the expected engineering performance of such materials when comparable laboratory tests are unavailable.

Jul 1, 2021

Supergene enrichment of ilmenite occurs through a complex series of reactions with initial oxidation and hydration followed by leaching and dehydration. Lateritization appears to be associated with the early phase of the supergene process and if ilmenite grains are encased in iron oxides no further alteration proceeds.

Jan 1, 1986

There is no good news! The market environment for raising capital for resource projects is getting tougher. The regulatory and accounting environment is fast becoming more difficult and the hurdles to successfully raising debt, lease, equity or hybrid finance are now considerably higher. As ever, well structured companies and capital issues can and will survive, if not thrive. An outline of the market and regulatory environment for successful issues is set out below, followed by some comparison of stockmarket values of resource assets compared to more technical appraisals.

Jan 1, 1990

By Goode RA

It is-assumed that a pipeline system is economically justified as a means of transportation.. The terms "True Life" and "Economic Design Life" are defined. The most usual design alternatives to be considered from both physical and economic -viewpoints are listed and a summary is given of the main factors to be costed in assessing the relative economics of each alternative. A brief statement of the recor mended method af economic. assessment is given and an example is included. The paper aims to present a reasonably accurate, simple and practical method of considering the main economic factors which govern design.

Jan 1, 1962

Attention is given to three possible alternative structures namely corporate joint venture, partnership joint venture and unincorporated joint venture. A corporate joint venture involves the formation of a separate and distinct legal entity with limited liability. The shareholders of the Company will be the members of the consortium. A partnership joint venture involves the members of the consortium joining a formal partnership. The partners will conduct the business in common with each other and will share the profits and losses of the project activities. The partners will be jointly and severally liable. An unincorporated joint venture is distinct from a partnership. The members of the venture will not be jointly and severally liable. Taxation and accounting aspects are examined and an outline provided of a typical joint venture agreement. The two main advantages of an unincorporated joint venture are considered to be a favourable treatment for income tax purposes and a greater degree of flexibility when compared with the corporate joint venture and the partnership joint venture.

Jan 1, 1983

The paper re-visits an old and proven concept of winzing, a method widely used in the past to gather exploration data for accurate definition of the orebody. It is proposed to use a mobile Supersucker (a giant vacuum cleaner also known as vacuum lift), to carry out winzing activities underground. A brief description of conventional underground winzing used in the past is provided, together with a discussion on other underground bulk exploration methods used in Australia to date. Historical background, principles of the proposed system, Supersucker construction details and productivities, and benefits and advantages of the proposed system in comparison with other exploration methods, are outlined. Other relevant applications of the mobile Supersucker, including surface winzing, are also briefly discussed in the paper. With a view of using the mobile Supersucker to recover all broken ore stocks underground, included are also results of floor sampling conducted recently in the in-stope decline excavated in a coarse gold type, high-grade orebody.

Jan 1, 2002

The ongoing need for improved fuel economy, longer engine life, reduced emissions and greater power output has driven the need for lower charge air temperatures. Cuamins will introduce a split loop, single water pump approach to low temperature aftercooling (LTA) in 1987 with the introduction of its 1492 kW (2000 BP) 16 cylinder K Series engine. The LTA system selection process considered performance, durability, fuel economy, and total engine installed cost. The split loop system selected takes full advantage of the engine cooling characteristics to provide optimum charge air temperatures at all speeds, loads and ambient temperatures. Computer simulations and engine tests were used to determine performance for each charge air cooling alternative. The split loop system chosen offers many advantages compared to the other alternative systems studied which included air-to-air and dual loop (two radiator, two water pump) systems.

Jan 1, 1986

A great part of the research on froth flotation of gold ores deals with ores containing gold associated mainly with sulphides, resulting in a largely accepted view that what takes place with sulphides (eg pyrite) in a flotation cell also happens to gold particles. This paper is concerned with the influence of some inorganics (CuSO4, CaO and NaCN) on gold particles flotation, using ethyl or amyl xanthates as collectors. The bench-scale tests were carried out with ground quartz and gold particles mixtures. Some findings stemmed from this study: flotation of the gold particles of size 0.16 mm was efficient adding only frother; larger gold grains were better recovered by the use of stronger collector CuSO4 did not seem to be an activator for gold; the addition of NaCN up to 200 g/t or CaO up to 2000 g/t did not depress the gold grains when amyl xanthate was used as collector although with ethyl xanthate the gold depression was verified.

Jan 1, 1993

Australia is a leading producer of mineral sands and according to U.S. Bureau of Mines, produced 24, 53 and 64% of world's production of ilmenite, rutile and zircon respectively in 1983. The industry which is mainly export oriented earned in export income about $210 million in 1985. The dominant position which Australia occupies in world produc- tion of mineral sands is also maintained in many areas of research and development work on the processing and application of these minerals. Some of this research which is leading the world has been responsible for setting up industries to produce value-added and high-tech products such as synthetic rutile and partially stabilized zirconia (PSZ). The production of high purity zirconia is due to commence shortly while research in rare earths offers an exciting prospect for future Developments.

Jan 1, 1986

Efficient performance of pulp lifters to discharge ground rock is critical to the effective performance of SAG and AG mills. The paper covers developments in the design of pulp lifters and associated grates, of both conventional straight-radial and curved types, and of the inner discharge cone. Issues covered include the discharge performance of both the slurry and rock components of the discharge, reverse flow back into the mill through open grates and backflow down the pulp lifters of material that fails to discharge from the mill. The design experience is interpreted in the light of developments in particle flow modelling of the flow of charge in pulp lifters.

Jan 1, 2004

By Staude W, Rosser A

Due primarily to the publication of the Fitzgerald Report the impact of taxation on the mining industry and the amount of taxes actual- ly paid by the industry have become items of intense debate. However, the discussion has been governed more by impassioned rhetoric than considered logic. It is equally as wasteful to the economy for the mining industry as a low cost efficient export earner to be punitively taxed, as it is for the industry to be given excessive taxation assistance. A comparison of the effect of five tax- ation policies on the cash flow of a capital intensive mining project is presented. The policies considered are Liberal 1969, Liberal 1976 with and without the coal levy, Labor 1975 and Labor 1976. The mining project used in the analysis is modelled on published estimates for the proposed Nebo coal project. The analysis is equally applicable to any large mining or petroleum development.

Jan 1, 1977

By Woods PW

Consulting Engineers have been used in the mining and metallurgical industries for many years. The traditional role of the consultant overseas has been one of assisting with conceptual design right through to con- struction and commissioning as well as on occasion acting solely in specialist fields. This role developed because mining companies wished to concentrate on building up the permanent organisation they require to operate their mines and treatment plants without the traumas of increasing staff for the design and construction period and reducing it on completion. In Australia where there have been few individual minerals projects of magnitude (until recently) companies have looked after their own detailed engineering and construct- ion management employing consultants mainly in specialised fields.

Jan 1, 1975

Outsourcing of mining operations and services is done for various reasons and there is no single model which fits all situations. Experienced contractors and mine owners have also developed, more often than not, jointly, numerous commercial arrangements and project delivery methods to suit their particular project. It is often the case that some mine owners who have not considered outsourcing to contractors do so because of a simple lack of understanding of the potential benefits. This paper will highlight the potential benefits and perceived disadvantages of outsourcing for mine owners and demonstrate how these issues have been addressed by the mining contracting community over recent times as well as demonstrate the evolution of current commercial arrangements in engaging mining contractors.

Jan 1, 2006

In those days no one worried - there were plenty of other things to do. But in'these days it is different. Everyone worries- and. because there is so much worry, emotion has entered the picture. And, worse than that, capital is being made in political circles. People who were quite unaware, five years ago, that any problem existed, have now become experts on the subject, and shout to high heaven that something should be done - and yet they go on using the leaded high octane petrol they deplore so much. And even scientists, who should know better, adduce only such evidence as fits the argument in hand. And the Press is not without blame - some of its reportings is open to serious question, whatever may be the excellence of its motives. The point is made that one should know what one is talking about. And make sure that the evidence quoted is fact - and make sure too, that all the evidence is used, not only that which suita the argument.

Jan 1, 1971