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By Wenya X, Bingchen C

About 60 per cent of magnesite ores of Haicheng Magnesium Mine, due to their low grade, are not currently commercially exploitable. In this paper, the flotabilities of the main component minerals of the ores were studied in detail with ether amine as collector. Based on. these, a new technique of reverse-direct flotation with single etheramine as collector for the beneficiation of the ores was developed. It gave highly satisfactory results. On the basis of the calculation by means of CNDO/2 method, of the studies of the solution chemistry of magnesite and of the adsorption tests and Zeta-potential measurements, the key mechanism in the new technique about activating effect of Ca2+ on the flotation of magnesite was suggested.

Jan 1, 1993

o Resource production is essential for society. o Demand for resources will increase as population grows.o Resource industries are the main consumer of trained geologists.o The lead time from(1) training to productivity(2) research to resource production is measured in years.o An adequate supply of well trained geologists and successful geological research is an important agent in ensuring cost effective, adequate supply of mineral resources for society. Therefore the main beneficiary of geological education is society itself.o Society is paradoxically apathetic or antagonistic to the resource industry because (1) it represents change(2) lobby groups working for other causes have successfully moulded a bogey man image for the resource industry in the public eye.Professional training and research for resource industries consequently lack popular support. Funding is at an absurdly low level in comparison with the economic importance of resource supply.

Jan 1, 1990

The concept of Extreme Gravity is the latest in a series of innovations that has seen a re-introduction of gravity recovery systems into the milling operations of most gold mines. Traditionally, most gold milling circuits are designed around flotation and cyanidation requirements, with the gravity circuit being fit in where possible. Extreme Gravity takes the novel approach of optimising the circuit, in order to maximise recovery by gravity. In some cases gravity systems can achieve high enough recoveries to eliminate the need for chemical systems such as cyanidation or flotation. There are many advantages of such a system including low capital cost, reduced permitting, improved cash flows and much reduced environmental issues. There are a number of plants currently in operation which utilise this new methodology. The Muzhievo project has been an example of a recent turn key success achieving recoveries from 85 - 90 per cent. The details of this project are examined as a case study.

Jan 1, 2000

By R Gaze, J Horton

Block models generated with all linear interpolation algorithms contain inherent smoothing that typically results in an underestimation of grades and overestimation of tonnes in resource estimates. For mineral deposits that are anticipated to be exploited by underground mining methods excessive smoothing may result in materially misleading estimates of Ore Reserves. To account for smoothing in the open pit mining environment recoverable reserve techniques such as indicator kriging and uniform conditioning are employed to provide non-spatially located proportions of the large blocks above the cut-off grade. These models are not suitable for underground mine planning where the actual location of material above cut-off is required to design its extraction. To correct for excessive smoothing it is proposed to modify the ordinary kriged block estimates a posteriori using an affine correction with a local variance adjustment factor. The proposed methodology is demonstrated for a base metal deposit during a feasibility study.

Jan 1, 2009

The authors are looking at the behaviour of the mineral processing circuits by means of the simulators operating under random disturbance. The present paper deals with the fuzzy control systems in comparison with PID controllers. A series of tests are conducted on simplified prototype processes with (1) dead time plus first-order lag model and (2) diffusive model. In the next series of tests the self-sustained process model was introduced to improve control against dead time. In both cases fuzzy and PID controllers are optimised by EVOP method. Particular attention is paid to the effect of observation noise to analyse for the problems which can be fatal to practical applications in mineral processing. Finally the methods developed are applied to a closed-circuit wet grinding system simulator operating under random disturbance.

Jan 1, 1993

Large scale rhyolitic volcanism is an important process at some convergent plate margins because it leads to chemical differentiation of the upper.-crust and is responsible for the production of long lived near surface thermal anomalies; the Taupo Volcanic Zone is.a Quaternary example. The main features of the magmatic systems-of the zone. are the existence of large high level chambers containing homogeneous silicic magma which erupt at intervals of thousands to tens of thousands of years. Geochemical work on the deposits resulting from these eruptions has shown that with few exceptions the magmas have been remarkably uniform in their . composition throughout the history of the zone although individual batches with lifespans of the order of. one hundred thousand years can be recognised by subtle differences in trace element ratios. Basalt is a rare proportion of the rocks exposed at the surface but has played a major role as a medium for heat transfer and as an end member in chemical mixing processes.

Jan 1, 1987

It has long been recognised that applications of the Net Present Value (NPV) investment decision making methodology can have serious deficiencies in situations where investment can be delayed and, once made, various options allow increases or decreases in the level of output. NPV valuation can undervalue the project if it does not incorporate future flexibilities or ""options"". It is important to realise that a proper valuation of a project (ie, valuation of its future cash flows) must incorporate an analysis of optimal future decisions involved in managing the project. Current valuation cannot be divorced from a consideration of future decision making. There is now a considerable amount of literature, mainly academic, identifying and exploring ways of remedying these deficiencies in the application of NPV. While the necessity of period by period analysis is sometimes acknowledged, little if any practical illustrative model building has been published to date, aside from algorithms using continuous time stochastic processes which deny access to the uninitiated.

Jan 1, 1994

By Corbett GJ

Epithermal gold-silver deposits occur in young volcanic terrains where post-mineral cover commonly impedes the search for mineralisation. At the Togi Project in Honshu, Japan, a complex mineralised system is largely covered by post mineral volcaniclastics. A combination of high resolution electrical resistivity surveying and detailed airphoto interpretation has, with close geological control, enabled synthesis of structural and alteration characteristics of the Togi geothermal system, in turn permitting ranking of the prospects for drill testing.

Jan 1, 1990

By R Balusu

This paper provides an overview of computational fluid dynamics (CFD) modelling capability developed by CSIRO with the aim of improving the knowledge of flow migration dynamics within longwall goaf areas. The CFD models can be used to study the ingress of oxygen into the goaf in different ventilation scenarios and goaf drainage arrangements. This approach not only helps the design of effective gas control strategies but also the management of spontaneous combustion risk in the goaf. Innovative goaf inertisation strategies have been developed and implemented during longwall sealing operations. Work is continuing to develop general guidelines of proactive goaf inertisation strategies to suppress the development of spontaneous heating behind active longwall faces.

Jan 1, 2005

By Morley I. W

Offshore minerals legislation has been introduced to provide jurisdiction over the exploration and recovery of mineral resources, particularly petroleum, from the territorial waters and parts of the continental shelves adjacent to coastal states. Ratificat- ion of the 1958 Geneva Conventions on the Law of the Sea has provided some measure of international agreement amongst signatory powers. Because the relationship of the Australian States to the Commonwealth in their federal system, the Australian offshore petroleum legislation is of particular interest. The customary role of the States in mineral resources management, which has extended to the offshore, is under challenge from recent unilateral Commonwealth Government legislative actions in the fields of mineral resources jurisdiction. Environmental considerations provide an additional issue, as yet unresolved, with the delay in submission of the Report of the Great Barrier Reef Petroleum Drilling Royal Commissions

Jan 1, 1974

By Thomas E. G

In the economic evaluation of any Australian mining project, changes in taxation can significantly affect viability. Australian tax laws, particularly in the period since early 1973, have undergone many changes which have led to shifts in the profitability of mining companies. This paper examines the sensitivity of a selected, broadly based sample of Australian mining companies to the changes that have occurred, or are reasonably likely to occur, in taxation legislation. In the past, tax systems have been altered for a variety of reasons, such as 1. reduction'in the impact of inflation 2. neutralization of incidence between different sections of the economy 3. as an incentive to encourage expansion and growth in a particular industry or area, and 4. increase in the real "take" of government. In this paper, conventional rate of return analyses are applied in a study of how profitability is affected under various taxation systems.

Jan 1, 1977

By R Nakia, R Livingstone

Historically the Goldfields of Victoria produced large volumes of gold. Interest in these historical Goldfields has grown over recent years with a view to restarting production of gold. A notable example of this is the Bendigo Goldfield. There is also interest in the Ballarat Goldfield and Ballarat Goldfields Ballarat East Project is a particular example of this. The aim of this paper is to describe the ventilation aspects of the potential Ballarat East project. The mine is proposed as a decline access. The paper gives an overview of the project and in particular the ventilation planning associated with a number of possible equipment scenarios. The paper also analyses the main ventilation pollutants that are likely within the proposed mine as it develops to increasing depth. An attempt is also made to determine the depth at which mine climate will become the dominant pollutant rather than diesel exhaust pollutants.

Jan 1, 2003

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

By Tyler MA

If the record of maj or proj ects in Australia is taken into account, it is apparent, the proper planning of an industrial relations strategy for many such projects has been ill considered by project developers. The recognition of the need to develop a plan from the initial feasibility study has been forced on those promoting new projects by the publicity given to the Australian industrial relations record. The delays in delivery caused by factors supposedly out of the project's control are often given for non-performance of contract and used as an excuse for limiting further development. Many of the problems experienced in project development can be overcome with sound industrial relations planning. The promises given in the euphoria of the early stages of a project relating to price and delivery often become a burden for the future because the complexities of the Australian Industrial Relations Systems are not understood or considered. The recognition by senior executives of their responsibilities in this area will contribute greatly to a new era of project development.

Jan 1, 1983

The progress of longhole open stoping (LHOS) at The Zinc Corporation, Limited and New Broken Hill Consolidated Limited (ZC/NBHC) is described. The design of a novel sloped wall longhole stoping method at NBHC which should allow the cuplete extraction of the orebody without the formation of pillars and with minimal dilution of the ore with sandfill is reviewed.

Jan 1, 1983

By Dixon CA

In the early 1970s, Jim Walter Resources, Inc. (JWR) embarked on a coal mine expansion program that was unparalleled in the history of the United States. With a small nucleus of people then operating two rapidly depleting captive mines, action was initiated to develop four of the deepest mines in the United States. Because of the depth of these mines, operational and technical problems were anticipated. However, because of the high quality of the coal (Blue Creek Seam), the financial risks involved were acceptable. The total investment to get the expansion program completed (to get the new mines to full capacity) would represent an investment of over US$ 500 million.By the end of the decade of the 1970s, the Company had grown to 2100 employees who were producing 1640,000 tonne of saleable coal per year, a productivity rate of 3.9 tonne per man-shift. This productivity rate was not sufficient to maintain a profitable, viable organisation. Therefore, if the operations were going to survive, it would be necessary to improve productivity tremendously, a task which would tax the resources and imagination of all employees.

Jan 1, 1991

By Pollard D. M

The removal of nickel from lead by sulfur drossing was investigated using a technique which models industrial batch decoppering practice. Successful denickeling to 0.005% (Ni)pb was consistently obtained in the absence of silver, well below the experimental equilibrium value of 0.015% but still above levels obtained in industrial practice. Silver appeared to have little effect upon denickeling. The final nickel content was dependent upon the initial nickel content, the total sulfur addition and the stirring time. The presence of nickel was found to give no assistance to successful decoppering. Simul- taneous removal of nickel and copper was observed at silver contents in excess of 0.02%. Extended stirring resulted in a further lowering of the nickel content but reversion of copper to the bullion was observed. Experimental work has shown that nickel can be removed by a standard decoppering operation; a procedure which is used in secondary lead re- fining. Alternatively nickel can be removed during initial decoppering in primary lead re- fining operations.

Jan 1, 1987

The production of 100,000 tonnes per year of synthetic rutile from the processing of ilmenite, coal and copperas (iron sulphate) produces 200 cubic metres per hour of effluent water. A 2.0 hectare biological filter, comprising natural and man- made wetlands, has been built into the last stage of the effluent water treatment system. It is an area of shallow water (

Jan 1, 1988

By G K. Robinson

The existence of bias in samples taken by cross-stream sample cutters has been investigated using three-dimensional discrete element method (DEM) modelling. Detailed quantitative information on overall extraction ratios, size specific extraction ratios, missed and extra sample components can be made by comparing a reference sample to the actual sample. A key advantage of using this modelling approach over physical experimentation is that the reference sample can be measured on precisely the same portion of the stream of material as the actual sample, thereby allowing the elimination of a significant fraction of the variability and allowing statistically significant results to be obtained using many fewer replicates. Quantitative analysis of results broadly supports the commonly-used rule that the cutter aperture should be at least three times the nominal top-size of the material being sampled, but does not support the commonly-used rule requiring increase in cutter aperture if the cutter speed exceeds 0.6 m/s. Sampler performance can be understood in terms of the balance of forces in the congested region of material formed by the slowing of the particle stream due to collisional interactions around the mouth of the cutter.

Jan 1, 2008

The Australian Mining Industry Council (A.M.I.C.) was established in 1967 as a body to co-ordinate the interests of the mining industry on a nation-wide basis. Its member- ship now embraces the great majority of mining groups in Australia. One of A.M.I.C.'s major continuing functions since its formation has been to work with Governments towards the enactment of more effective and efficient mining legislation. Yet, over the period, the,overall position, if anything has deteriorated. The main reason for this was that because of the rapid succession of what appeared to be quite separate problems during the period there was never sufficient time for Govern- ments to take stock of a situation before it would be changed by a new set of circumstances. By early 1973, the Council was certain that most of the various questions raised were really part of the one overall land use problem and its work in this area thus took a new emphasis from that time. In discussing the Council's involvement with Australian mining legislation over the last six years, the paper helps to clarify the present situation. It then explains a land management system which the Council believes could pro- vide the basis for the type of enlighened

Jan 1, 1974