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By B J. Wight, R Mackay, S Kim

Improving the understanding of the processes governing ground movements in and around brown coal open cuts is of significant interest for both operating stability and rehabilitation. Brown coal, lignite, is a low-rank coal that is best described as a soft rock, with geotechnical characteristics that derive from its organic origin. It is well-known that low-rank coals exhibit creep behaviour; however, little has been reported on the impacts of chemical processes on brown coal creep behaviour even though organic substances are susceptible to chemical alterations and mining processes will contribute to changes to the geochemical environment; around most mines, groundwater flow patterns are altered leading to enhanced surface water infiltration. Here we study the deformation behaviour of brown coal in response to ion exchange reaction. Our experimental results show that for different ion exchange conditions different characteristics of secondary compression are observed. With the addition of Ca2+, the ratio between coefficients of secondary and primary compression (Ca /Cc) initially decreased, presenting a minimum value at the concentration of 0.005?M, then increased significantly. This implies the importance of ion exchange process for the long-term deformation of brown coal. On the other hand, increasing Na+ concentration did not affect Ca /Cc values significantly over all tested concentrations. The suppression of diffuse double layer was still observed for Na+-treated samples as increasing Na+ concentration decreases Ca values. From a practical perspective, this study did not consider the tertiary creep behaviour and eventual creep failure.CITATION:Kim, S, Mackay, R and Wight, B J, 2014. Creep due to chemical alteration of rocks – a case study in brown coal, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 61–64 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By M.E. Crump

Gallium occurs at above background levels in most samples collected from 11 of the major geothermal areas in the Taupo Volcanic Zone. Concentrations of Ga in the 48 samples ranged from 8 to 144 mg kg-' and varies widely from place to place within each geothermal area. Gallium is contained within the alumino-silicate structure of clay in the mud, having substituted mainly for Al. Suggested deposition mechanisms for Ga also involve co-precipitation with Sb, As, and SiO. colloids. Digestion trials, carried out to determine extraction conditions for possible commercial exploitation, showed that heating the mud to 500 -600¦C for 1 hour followed by acid/alkali treatment gave complete recoveries.

Jan 1, 1995

A variety of algorithms and methods are being used by the mining industry today to map mineral resource for reserve estimation. The traditional methods including Polygonal, Sectional and Inverse Distance methods are relatively easy to understand and implement. They have served industry well for several decades and should continue to do so for the large bulk mineable deposits with very regular geometries with relatively small variation in grade.

Jan 1, 1992

In December 1997, a series of new environmental legislation was enacted including:ò Environmental Planning andAssessmentAmendmentAct 1997; ò Contaminated Land ManagementAct 1997;ò Protection of the Environment (Operations) Act 1997; ò Native Vegetation Conservation Act 1997; andò Pollution Control (Load Based Licensing) Act 1997.These new Acts will have varying degrees of impact on the coal mining industry in New South Wales when they commence later this year.

Jan 1, 1998

The results from three quick methods for the determination of W03 in scheelite ore samples, mill products and concentrates were compared with gravimetric results and tested with standard samples to establish which was the most reliable. Summaries of the methods, two X-Ray fluorescence and one colorimetric, are given. The best method was X-Ray fluorescence, with samples cast as glass discs.

Jan 1, 1988

By Burton E, Eaton R

The incentive to improve wear resistant materials performance is examined with respect to plant availability and recent trends in the labour force. Standard practice at Isa Mine Concentrat- ors in countering the effects of abrasive and corrosive wear is discussed with emphasis on results with more exotic materials such as ceramics and the Cr-Ni-Mo white irons. The paper updates work on rod and ball mill Linings.

Jan 1, 1978

The procedures for an audit and review process upon which continuous improvement programs may be based are described. The case for regular audits of mining operations to establish performance trends is advanced. Analysis of performance data using the parameters of the capacity equation used in conjunction with learning curves is described. The extrapolation of learning curves in performance target setting, operating and capital cost budgeting is advocated.

Jan 1, 1992

The occurrence is recorded of an indurated kaolinite claystone associated with red-beds in the Burralow Formation of the Narrabeen Group near Putty toward the north-west of the Sydney Basin. The claystone is similar in composition and structure to the Garie Member which immediately overlies the kaolinite-rich "chocolate shales" of the Bald Hill Claystone in the sofrthern part of the basin. Unlike the Garie Member however, the Putty claystone is lenticular and the associated red-beds contain abundant quartz and illite in addition to kaolinite.The source of the Putty claystone is not known. Possibly it is an extension of the Garie Member to the northwest or alternatively, it may represent fine outwash of detritus that produced the coarse-grained kaolinite claystones in the Triassic succession of the Merrygoen-Binnaway area. Although the material is suitable for the manufacture of aluminous refractories the limited size of the deposit precludes its commercial exploitation.

Jan 1, 1971

By Pratt IJ

A report is given of the problems of finance and physical resources that currently affect The University of New South Wales, and of some of the measures adopted to alleviate them. Partly as' a result of review procedures, a School of Mines was formed to amalgamate Applied Geology and Mining Engineering, and to add the skills of extractive metallurgy to produce a group to match the needs of the minerals industry. A review of courses within the School indicated a need for enhanced computer teaching, which is partially negated by a lack of resources. It also shows an overcrowded course whose structure could possibly benefit from a split into managerial and specialist streams.

Jan 1, 1986

The purpose of this paper is to outline the current status of financing in the Australian Gold Mining industry and to discuss a number of developments that have occurred during 1983/84.Recognising the importance of equity financing various equity issues, including project valuation, will be discussed against the backdrop of an industry experiencing both rapid growth and a changing structure.Nothwithstanding the current tax exempt status of the industry there is a trend towards more debt financing. A number of financing issues will be covered and it will be shown howvalue can be created through astute financing planning.

Jan 1, 1984

By L Grigorov, G J. Jame, A V. Nguyen

The dewetting kinetics between a small air-liquid interface and a silica (negatively charged in water) planar surface in solutions of dodecylammonium chloride (cationic surfactant) has been investigated using the Scheludko cell and digital high-speed video microscopy. The gas-liquid interface was created at the bottom of a small silica capillary of the cell and then was moved towards the silica planar surface. After the rupture of the liquid films between the interfaces, the expansion of the gas-liquid-solid three-phase contact (TPC) line was observed and recorded using a digital high-speed video microscope system, operating at 1000 frames per second. The surface tension of the surfactant solution was measured using the pendant drop technique. The equilibrium contact angle was measured using the Scheludko-Minings method with a silica micro-sphere. The TPC radius was determined as a function of time and compared against the available hydrodynamic and molecular-kinetic models. The experimental data are described very well by the molecular-kinetic model for the TPC line motion. The hydrodynamic model is in agreement with the experimental data only for a short time after inception of the three-phase contact expansion.

Jan 1, 2005

In todayÆs demanding business landscape continual change and technological advancement is a given. With these changes there is now, more than ever, a need to ensure sustainable growth in respect of value protection and value adding whilst meeting the pressures and expectations of the societies in which we operate. Traditionally the management of safety has been a very reactive activity in the business, in some cases seen as an irritation and a disruptive process that demands a focus on preventing reoccurrences. This in turn has focused the measurement of safety performance on a range of lagging indicators û æafter the effect managementÆ. Gaining and maintaining a licence to operate is crucial to a sustainable business but as a prerequisite, organisations need to have a demonstrable ability to manage the safety of their people, as well as mitigating the people risk associated with the business activity. A major focus in the last decade has been on the implementation of enterprise risk management programs, where risk becomes embedded in all business systems and processes and the organisationsÆ genetic make up is programmed to analyse and integrate risk management into all facets of the business activity. The management of safety should be no different. One school of thought argues that there are no new accidents, but rather our inability to learn from the past. Others believe that as long as we have an appetite to achieve the unachievable, we will have to continue to push the boundaries, our safety comfort zones and inevitably take risks. Single reliance on highly evolved technical systems, elaborate processes, highly skilled people, safe equipment and safe work environments have shown one thing û they are not sustainable in providing adequate coverage in the business. In analysing a range of factors associated with some of the worst catastrophes of the 20th century, it can be suggested that they were in fact predictable and inevitable and that an integrated approach underpinned by sound risk management systems could have determined a different result. The key to a sustainable approach in the management of safety requires us to look at a multitude of aspects that collectively allow the performance of an organisation to be predictable. To have certainty in the business activities it is necessary to have controls in place that will mitigate the risks normally associated with unwanted events. It is ensuring that human factors effectively contribute to monitoring the planned approach and being able to safely adjust to any variability. In essence this is having the ability to proactively plan for the longer term. The sentiments articulated by organisational leaders echo that safety management is good business. Surely then a good business is a sustainable business, and a sustainable business is one that provides lasting benefits to its stakeholders.

Jan 1, 2006

By J D. van Wees

Preliminary project evaluation is relevant to the evaluation process of the decision makers (or executives) prior to making the critical business choices. Important to the assessment is an integrated sensitivity, scenario and risk analysis at every stage of a mining project. This should include the evaluation of different options taking into account uncertainties. Construction of interactive financial computer models where each element is functionally integrated into a fully integrated life-cycle allows rapid and automatic study of the sensitivity of each element through changes in the value of an input. The scenario analysis is the effect of changing more than one input at a time, organised through scenarios in a decision tree. Risk analysis is an integrated analysis of the effect of all uncertainties of the parameters, using Monte Carlo simulation. Key to the asset decisions process is that the decision maker is provided with the essential integrated decision information. We have clustered this information into several scenario groups. Within each group, two levels of uncertain information are distinguished: discrete scenarios critical for the decisions; and remaining uncertainty within the scenario (risk analysis) which can be modelled by continuous probability density functions (pdfÆs). For an asset, the relevant scenarios in each group and the associated continuous pdfÆs need to be defined. When the scenario groups and associated pdfÆs have been defined for the asset, the decision process can be started by structuring the different scenario groups in a Scenario Tree. A Scenario Tree contains decision and end nodes. Each end node corresponds to a completely defined mine project or asset model. The calculations for each end node result in a set of stochastic realisations for the reserves, production forecast, cash flow, and profitability indicators (NPV, IRR, DPR). Thus, a deterministic and fully probabilistic multi-commodity analysis tool is provided to investigate the sensitivity and robustness of decisions.

Jan 1, 2003

By Dobias B

A new separation method based on a combination of coagulation and colum flotation was used to treat fine sphalerite in the range 90 per cent - 15 pm with a relative high superfical gas velocity and a thick froth layer. Minerals studied include sphalerite, calcite, kaolinite and baryte. A new developed sedimentometer was used for sedimentation analysis to characterise hetercoagulation of mixture and coagulation after addition of active ions or reagents. A comparison between use of selective frother and depressant (SHMP) was made to deactivate activated minerals. Selectivity of frother for sphalerite was found in flotation test. The depression function of Flotanol for activated minerals was confirmed in sedimentation alalysis. The use of small quantities of HPAM can improve the flotation of fine sized sphalerite particle and reduce recovery of activated gangue minerals in the neutral or alkaline pulp. A satisfactory separation of fine sphalerite from its gangue was achieved by using alkylpolyglycolether (Flotanol) and copolymer polyacrylamide (HPAM hydrolysed polyacrylamide) as frothing and flocculating agents Respectively.

Jan 1, 1993

An efficient stores organisation is essential for an efficient undertaking. Unless the stores organisation is able to meet the requirements of its requisitioners promptly and economically, the undertaking as a whole cannot function efficiently.Delays or errors in supply of material, or substitution due to lack of material availability from the stores are costly and must be eliminated. This then makes the objective of a store, to supply on demand at the cheapest possible price, those items of stock which it is organised to carry, also to procure as quickly as possible and at the lowest price those special items required which are not normally carried in stock. To do this it is necessary to set up a stores organisation consistent with the size and requirements of the undertaking. Stores organisations vary with the nature of the undertaking they are designed to serve. In the case of the Broken Hill Associated Smelters Pty. Ltd., an organisation has been established to meet the operating and maintenance requirements of the Port Pirie Works. These embrace the particularly wide range 0:1; activities associated with roasting" blast furnacing and refining the lead concentrates from the Broken Hill Mines in a continuous metallurgical process producing a variety of refined metals; also many associated activities including power production and engineering maintenance and construction.

Jan 1, 1951

By E House, V Lisitsin

Recent whole-rock geochemical data from nearly 900 fresh drill core and underground samples taken from seven central Victorian gold deposits confirm the presence of distinct and identifiable primary alteration haloes surrounding the deposits. Ferroan carbonate alteration extends for up to several hundred metres away from turbidite-hosted gold mineralisation outside of contact metamorphic aureoles. A less distinct phyllic alteration zone can be identified using geochemical molar ratios or short wave infrared analysis. It generally overlaps a sulfidic halo characterised by disseminated pyrite and in close proximity to mineralised structures, arsenopyrite. The extent of the sulfidic halo can be traced using low-level analysis of pathfinder elements such as S, Au, As and Sb. Recognition of these alteration features enlarges the target for exploration and provides a tool by which drilling can be directed towards mineralised structures. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

With the evolution rate of technologies, earthmoving equipment users are establishing vision statements for their operation out to and in some cases beyond 2000. Autonomous systems are receiving a lot of 'press' - and rightly so, as they hold a potential for achieving quantum leaps in productivity and cost gains. Caterpillar feels that it is important that the infrastructure of on-board systems are understood and can be utilised more in the near term to `grow' a user up to the stage of autonomous operation.

Jan 1, 1997

By U Briem, R Verreet

The level of wire rope technology used in mine hoisting applications has a significant effect on the overall efficiency of the hoisting system. This paper discusses the effect that a reduction in rope mass per unit length and an increase in rope breaking strength can have on rock skip capacity and hence mine shaft output. A 20 per cent reduction in rope mass per metre for a typical 48 mm hoisting rope, while maintaining the breaking strength, increases the skipÆs capacity by circa 30 per cent at a suspended rope length of 3000 m. Such gains in shaft output, without any significant changes to the shaft or winder design, can have major implications for the feasibility of future deep mine projects. The technical challenge for rope manufacturers is how to get rid of 20 to 30 per cent of the rope mass while keeping the breaking strength and modulus of elasticity of the whole rope constant. CASAR are currently developing steel wire rope constructions where the steel IWRC has been replaced with high strength, high modulus fibres such as Kevlar«, Spectra« and Dyneema«. One of the key aspects of such composite rope designs is to ensure equal load sharing between the different rope components, ie in proportion to their area. If there is a significant difference in modulus between the fibre core and the steel outer strands, the core may not carry its proper proportion of the load and the outer strands would be overloaded. Some technical aspects of the design of composite steel wire ropes are discussed. A design and operational issue that needs careful consideration is the safe non destructive testing (NDT) of composite ropes. Traditional magnetic NDT would only be capable of inspecting the steel wires. Techniques therefore need to be developed that would give operators a reliable indication of the condition of the load bearing fibre core. This paper also discusses possible solutions to this very important NDT question.

Jan 1, 2005

By P J. Hansen, D G. Franklin, M E. Trim, J V. Myers

The Northern Sewerage Project (NSP) is an upgrade to one of MelbourneÆs ageing, under-capacity trunk sewers. It will reduce the volume and frequency of wet-weather overflows to the Merri and Moonee Ponds Creeks and facilitate new housing developments in the northern suburbs of the city. A total of 12.4 km of tunnel and eight vertical access shafts will be excavated as part of the two project stages: Stage 1 (NSP1) will be owned and operated by Melbourne Water (MW) and Stage 2 (NSP2) will be owned and operated by Yarra Valley Water (YVW). The owners require the project to have a service life of 100 years, a requirement significantly beyond many of the current Australian Standards, which aim to achieve service lives greater than 60 years but are typically assumed to achieve 40 to 60 years. Because of the potentially corrosive natures of the external environment along the tunnels and the internal sewer environment, durability was a key concern for NSP1 and NSP2. Stringent specifications were applicable to the tunnel lining systems. This paper describes the corrosive environments impacting NSP1 and NSP2, explains the key design differences between the two stages and details the lining systems considered and selected to achieve the clientsÆ desired 100-year service life. The project design is complete and construction began in 2007.

Jan 1, 2008

Currently, mining in Australia underpins the economic vitality of the nation, generating massive revenue from commodity exports and providing substantial infrastructure and employment. In addition, it is predicted that mining related services will in the future develop a global market of their own that could eventually grow to rival, in value, the export trade in mineral commodities. There is however little room for complacency. In the short- to medium-term, escalating, vigorous competition can be expected from many previously underdeveloped countries that are reforming their own mining and mineral export industries. In addition, most mining companies are facing a modem-day renaissance in terms of new expectations, changing social norms, evolving employee relations and statutory obligations. Thus, along with whatever promise the future might hold, the mining industry is currently being subjected to a growing number of largely unprecedented problems and pressures, both economic and social, that are both highly complex and demanding. In particular, it remains a matter of on-going concern that relations between mining companies and their employees still, in spite of recent reforms, continue to constrain productivity, perpetuate inefficiencies, affect quality of work life and retard progress towards mutually beneficial goals and achievements. If mining in Australia is to attain and hold on to a commanding position on the global scene, then further changes will clearly need to be made. Realisation of this appears to be growing, with most mining companies having attempted in recent years to improve workplace culture. Based on a wide ranging study, this paper presents an overview of what has been learned to-date with regard to the `people factor' when it comes to implementing and progressing positive change and reform in mining. From this, a number of practical suggestions, arising from hard won lessons and experiences in the field, are offered. Attention to the nine `key principles' given should help to ensure that many of the common problems encountered to-date with change and reform in the mining industry are in future avoided or at least minimised.

Jan 1, 1997