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Using a new type of laser surveying instrument named Particle Dynamics Analyser (PDA), the distributions of the radial and axial components of the mean velocity, the size and the concentration of solid particles at selected positions within a transparent hydrocyclone were directly measured out for the first time, from which profiles of the flow field of solid particles were obtained. And some new points were put forward such as the locus of zero vertical velocity (LZVV) of solid particles was not the same as that of liquid, and some particles in inner helical flow could also be separated. The results are of great significance to farther ascertain the separation principle of hydrocyclones and improve the separation efficiency.

Jan 1, 1993

By Kellett KR

Gold Mining at the Lancefield Mine was commenced initially in 1897 and continued intermittently through to 1956 when rising costs and mine cave-in forced closure. The mine was redeveloped in 1981 and a new-oxide treatment plant commissioned, followed by a new refractory treatment plant in late 1982. Both these treatment plants are located within the Windarra Nickel Project plant area.The refractory ore is processed by fluidised bed roasting of flotation concentrates. This is carried out in two series connected reactors to maximise arsenic and sulphur eliminations and to minimise reagent consumption. For gold recovery the zinc precipitation process was initially used, to be later replaced by carbon-in-pulp.

Jan 1, 1984

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

Renison Goldfields Consolidated Limited (RGC) and Consolidated Gold Fields Plc (CGF) purchased New Guinea Goldfields Limited (NGG) in 1982 as an exploration venture. Following an intensive drilling programme in the Upper Ridges area sufficient ore reserves were outlined to justify the installation of a new 700 tonnes of ore per day gravity gold extraction plant. Major considerations in the design of the new plant were to minimise production inter- ruptions in the existing plant and to include simple, but technically efficient, equipment that could be operated and maintained by a workforce with limited experience in modern technology. These goals were achieved over a six month period, commissioning being carried out in April, 1983. Mining the epithermal gold deposit is by open cut benching and truck haulage. The gravity concentrator includes a scrubber, wet hammer mill and rod mill, to crush, grind and prepare the ore for sizing and desliming. Gold recovery units consist of a jig, spirals, shaking tables and amalgam barrels. Although the majority of the gold is in the minus 100 plus 20 microns size fraction a recovery of 63 percent, from a head grade of 2.0g/tonne, is Achieved.

Jan 1, 1984

By K Guilfoyle

AngloGold Ashanti Australia Ltd operates an underground mine below a large open pit at the Sunrise Dam Gold Mine near Laverton in Western Australia. Operations are based on an extensive mineralised zone which has very complex geometry, has a high ‘nugget effect’, and is difficult to interpret and model. Initial underground ore was produced from relatively narrow orebodies dipping from 15º - 70º. Open stopes aimed to selectively extract high-grade ore, using methods including jumbo stripping and longhole drilling and blasting. The complex geology makes it difficult to accurately locate development and stopes in the positions required for profitable production. In narrow stopes, rock mass damage and overbreak dilute ore grades and increase the cost per ounce of gold poured. In flat orebodies, several different techniques have been used to recover blasted ore but overall productivity is low. Thus selective mining can also be slow, costly and recovers only a portion of the available mineral resources. Large longhole open stopes with cemented paste backfill are used to extract multiple zones of mineralisation from the Cosmo and GQ orebodies. Bulk emulsion explosives and electronic detonators are used in all large stope blasts to reduce the risk of misfires and to accurately control blasthole initiation sequences and delay timing. Larger stopes improve productivity and significantly reduce direct mining costs, enabling the use of lower economic cut-off grades which increase the overall recovery of mineral resources. This paper reviews the evolution of open stoping at Sunrise Dam, the various mining methods and drilling and blasting practices used, the results achieved, and the lessons learned.

Nov 8, 2011

By J Loeb, D Thornton

Blast movement measurement is a key component of grade control, enabling mines to carry all of the precision involved in locating ore blocks, through a chaotic blast, to production. A monitoring system was developed about ten years ago so that mine operation personnel can measure three dimensional movement in every production blast. Research has shown that blast movement is always highly variable with a significant non-deterministic component. The consequence is that modelling will be inaccurate and therefore optimal ore recovery can only be achieved by direct measurement of blast movement.Three dimensional movement vectors are measured at discrete locations in the blast. If blast movement is only measured at one location in a blast pattern, data is severely limited and has all of the inherent inaccuracies of modelling a variable population. It is intuitive that the accuracy of defining the post-blast ore block mark-ups are proportional to the number of movement measurement locations, however increasing the number of monitoring locations causes increases to the direct operating costs of the mine.A cost-benefit analysis is used to explore the optimal number of monitoring locations. Using the method described in this paper, an automated selection of the number and location of blast movement monitors are analysed against the value of recovered ore compared to the control, for each trial.CITATION:Loeb, J and Thornton, D, 2014. A cost benefit analysis to explore the optimal number of blast movement monitoring locations, in Proceedings Ninth International Mining Geology Conference 2014 , pp 441–450 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By M Mee, R L. Gwyther

Accurate measurement of rock mass response during the mining of massive underground orebodies is essential, as mines become larger and deeper. These measurements enable: provision of quantitative data for optimal pit slope design and engineering; monitoring of the stability of deep pit slopes, the long-term integrity of shafts and large-scale underground infrastructure, and long-term measurements of deformation or rock mass creep following the mining process for environmental management. Strainmeters traditionally used for deformation measurement have neither the long-term stability nor the high sensitivity to perform measurements in these applications. This paper describes a new precision borehole strain monitoring system (GTS) currently deployed by CSIRO Exploration and Mining, which has the potential to solve these new issues in rock mass deformation monitoring. This technology was originally developed for use in hard rock mines (Gladwin, 1977) and refined considerably for earthquake research (Gladwin et al, 1994; Gwyther et al, 1992). A case study of the use of the GTS in monitoring longwall coal mining over the period 1993 - 1998 is presented.

Jan 1, 2000

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

The Electricity Commission of New South Wales is the largest single user of coal in the State, burning some 8.5 million tonnes during 1972-73. This coal is converted in power stations into electrical energy which is then distributed throughout the State and supplies the electricity requirements of 99% of users in New South Wales. Barring any major change in energy consumption growth, or change in the current mode of power generation, the consumption of coal by the Commission is estimated to have a doubling period of from 10 to 14 years. Coal is used to generate up to 87% of the electrical energy sold, the balance being obtained from hydro gen- eration, mainly in the Snowy Mountains, and, to a much smaller extent, from diesel generation at Broken Hill. A very large proportion of this coal is consumed in pulverised fuel boilers in the Commission's power stations, located mainly on the various coalfields of New South Wales. Coal supplies are drawn from a large number of mines, some owned or controlled by the Commission, others being owned by public companies. The coals used, originate from at least ten different seams located in the northern, western and southern coalfields of New South Wales, and therefore have a wide variety of properties and characteristics. To ensure an adequate fuel supply well into the future, the Commission is continuously engaged in coal prospecting in various areas. Bore data is used in assessing coal reserves and is also the basis of economic studies for their possible future exploitation. The numerous coal cores obtained during drilling operations are carefully tested and analysed in order to assess their suitability for power generation purposes, and to provide data for the design and operation of boiler plant using these coals. In existing power stations coal deliveries are systematically sampled and tested for quality control, for pay- ment of purchases based upon certain quality parameters and to check for any possible plant operating or main- tenance problems that might arise from the use of the particular coals. Almost all the properties of coal that may be necessary in the Commission's work are obtained using standard testing procedures carried out by the Commission's chemists, in laboratories located at the various power stations or at its Central Laboratories in Pyrmont. Where specialised analysis or testing is required, this is ordinarily undertaken on a commercial basis by outside bodies, expert in the particular field. The significance of the various properties of the coal for use in p.f. boilers is outlined and related to their proper application to boiler plant design and to plant operation.

Jan 1, 1975

By P Lukic

The definition of the working sections that will be used in a mine is usually initially made in the field by the geologist supervising the drilling program. These initial definitions are often made on the basis of rules of thumb such as æcoal less than 30 cm thick cannot be mined separatelyÆ; æpartings more than 30 cm thick will be mined separatelyÆ; and æif a coal seam is less than 50 cm thick and the parting above or below is thicker than the coal, the coal will be wastedÆ. These decisions are also often made based on the requirement for a minimum sample mass for analysis, and the desire to collect data at the minimum resolution to conserve the exploration budget.In many cases the geological models based on this data are produced at a resolution that is inadequate to allow the mining engineer to produce a mine plan that will maximise project value. This problem is generally unrecognised.Where data is collected to a higher level of resolution the subsequent processes employed in the production of geological models and mine plans often discards the inherent value that is hidden in this data. Again this problem is generally unrecognised.This paper highlights this problem and then presents a methodology that ensures that the optimal working section is selected and compares the outcomes of applying this methodology versus adherence to the usual rules of thumb.

Sep 26, 2011

By P Moarefvand, M Osanloo

The anticipated economic life of the mine, which defines the rate of mine production, is dictated initially by the design capacity of the mill/concentrator and the production capacity of the mine relative to the grade and tonnage of ore that can be encompassed by the pit design. A small pit will result in smaller investment and cash flow; in contrast, a larger size of pit will increase capital investment and annual revenue. Since open pit mine design and long-term production sequencing are essentially based on three-dimensional block models, changes in block dimensions leads to different mine sizes, and therefore changes in the mine life. The physical characteristics of the deposit, such as reserve tonnage and ore grade, affect the expected future revenues from the mining project, and consequently they affect the life of the mine. Large blocks will increase the recoverable ore reserves and production rates and hence increase the mine life. This paper discusses the effects of the block dimension on the commercial ore reserve, grade-tonnage curve and its effect on the production rate, ultimate pit size, mining cost and consequently the mine life. The result shows that block height is the most effective parameter governing the economical life of the mine.

Sep 26, 2011

By D Elder, S Bell

Over the last five years Solid Energy New Zealand (SENZ) has gone through a series of changes in response to both external and internal factors. These changes have included corporate reorganisation and funding restructure, as well as modifications to medium and long term business objectives. The nature and size of its coal reserves and markets requires SENZ to continue developing new mines as existing mines are depleted. As well, there are opportunities to develop new mines as coal markets change or to realise value from existing coal resources. To assist in this process, a set of mine project assessment guidelines which are relevant to the size and scale of anticipated mine developments have been developed for SENZ. These project guidelines are structured to operate from the early stages of project or resource review through to final feasibility study stage. The guidelines provide both a basis for planning and budgeting, and a control mechanism within the company. They also enable clear understanding of the status of individual projects and provide a framework for comparison between projects. SENZ now has a defined method to plan, monitor and control this important aspect of its business. The paper explains the development and structure of the guidelines, as well as providing examples of their application. and use. It demonstrates how SENZ integrates its long term planning, five year planning, annual planning, project planning and risk management to maximise the value of individual projects, business units and the company overall in a consistent manner.

Jan 1, 2002

The five main ways in which coal is used are1. for electricity generation,2. as a lump fuel for domestic and industrial purposes,3. for gas making,4. for making carbon for chemical and metallurgicalindustry, and5. as a source of coal tar and coal-tar chemicals.In the past about 80 per cent of Victoria's brown coal has been used for power generation and the rest for making a lump fuel, in the form of briquettes. Some of these briquettes have been used for gas making, and a carbon industry based on them has recently been commenced, and could expand rapidly. However the enormous increases expected in power requirements, approximately a doubling every 10 years, will ensure that even if the manufacture of carbon increases dramatically and a large amount of coal is used for other purposes, the brown coal industry will always be dominated by power generation. As new fuels such as natural gas, oil, and nuclear fuel become available at competitive prices these will take their share of the power generation load.Natural gas or oil, or possibly pumped storage hydro, will almost certainly be used for all future peak-load stations, comprising around 40 per cent of the total installed generating capacity, but new base load stations will continue to be designed for brown coal operation until about the mid-1980s, by which time nuclear power stations will become competitive. By this time Victoria will have installed about 6000 MW capacity of brown coal stations, burning around 50 million tons/year of coal, compared with 18 million tons/year at present, with perhaps 15 million tons/year being used for other purposes.This consumption of 65 million tons/year should then remain fairly stable over the life of the power stations installed, well into the 21st century. Brown coal therefore appears to have an assured place in providinga major part of Victoria's fuel requirements, despite the diversification in fuel usage pattern which appears certain to occur with the recent developments in new fuel resources.

Jan 1, 1971

By N Wharmby

In recent years in New Zealand there have been a number of tunnelling and deep directionally drilled pipelines projects that have required access shafts. Often these shafts are in urban environmentswhere vibration and high noise levels are not tolerable. There are a number of methodologies that can be adopted dependent upon the shaft plan area, depth and geology.This paper will describe some different methodologies that can be adopted that use piling methods such as large diameter piles, and secant piles. The paper will use case studies to highlight:· construction methodology,· specific methodology issues and constraints,· lessons learnt, and· recommended specifications.The development of piling technologies in New Zealand has enabled the development of cost effective solutions for the construction of deep shafts in sensitive urban environments.

Mar 8, 2011

By Bourgeois F

The population balance concept has provided a useful framework for the description of the operating behavior of the ball mill. This approach finds expression in the so-called selection breakage function model for batch and continuous mills. This model produces very good descriptions of the size distribution of the products from ball milling operations and the model is very useful for the description of batch and continuous mills and, when combined with models for classifiers and other unit operations, provides a solid basis for flowsheet simulation procedures. The breakage and selection function model is essentially descriptive and not predictive because the parameters in the model cannot as yet be related to the fundamental material properties of the material that is broken and to the fracture mechanics that govern the comminution of brittle particulate material during the rapid impact and compression events that occur with high frequency in a ball mill. The population balance approach smears over the individual processes and regards the ball mill as a continuum with breakage occurring continuously in time and space. New experimental techniques, particularly the adaptation of the Hopkinson bar as the ultrafast load cell (UFLC) to the problem of observing the extremely rapid impact fracture of particulate solids, have made it possible to make accurate and consistent measurements of particle strength, particle fracture energy and the single-impact breakage function. These quantitative measurements have been incorporated into a new conceptual model for the description of the ball mill. The model is based on identifying all events that give rise to particle breakage, and using the fundamental experimental data obtained on the UFLC and other single-particle fracture tests, the probabilities of these events can be independently determined. The distribution of impact energies that occur in the ball mill has been established by discrete element simulation of the media motion. The probabilistic description of the individual fracture events and the distribution of impact energies are combined to make a priori predictions of ball mill performance under a variety of operating conditions. The new model is used to calculate the selection and breakage functions for quartz in a small batch mill.

Jan 1, 1993

By McMahon DW

The major components of a mineral reserve estimate for project development purposes are described with respect to sampling, geology, estimation methods, mining factors, metallurgical factors, environmental factors, financial and other factors. Each of these components impact to varying degrees on the recoverable metal or product of a new mining project. The evaluation of a project is a complex process involving the best the profession can provide in terms of geological understanding, engineering ingenuity, metallurgical skills and financial evaluation.

Jan 1, 1983

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

By T D. H McGrath, O Baker, W P. Staunton, C Ypelaan

"The carbon-in-pulp process has been used extensively in the gold industry since the late 1970s to recovery leached gold from solution. Despite more than 30 years of experience in operating carbon circuits, average gold solution loss has remained at an average of 0.02–0.03 ppm (mg/L), higher than the ‘best practice’ target of 0.01 ppm.Process modelling, such as SIMCIL developed by the Curtin Gold Technology Group (GTG), can provide information on optimum set points; however, manual control of the circuit limits the potential benefits.An automated carbon measurement device, the Scout Carbon Meter, has been developed to allow for automation of carbon concentration measurement, and automated control of the carbon transfer pumps. This paper describes the results from the evaluation of the first two prototypes of the meter.Citation:Staunton, W P, McGrath, T D H, Ypelaan, C, Baker, O and Eksteen, J J, 2016. Optimising Carbon Management - Increasing Gold Recovery and Decreasing Costs with the Carbon Scout, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 225–228 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

The topic for my address is Sharemarket Floats - Issues for Expert Valuers. I've decided to focus on three areas where current practice in the preparation of prospectus valuation reports for resource companies might be improved. My central theme is that the valuer for a float should augment the usual assessments of the value of the company or its assets, with some input on the way the share market might value the company's shares when they are listed. I will then look at the valuer's role in relation to vendor consideration, last I will look at his role in providing investors with some input on the risk dimensions of the new company.

Jan 1, 1989

By B Ghahreman‐Nejad, M Munro

Design of embankment dams often requires seismic analyses, or an assessment of earthquakeinduced ground and dam movements. There are a large number of cases where earthquakes have triggered sliding and lateral spreading of embankments, resulting in excessive crest settlements. In some instances, liquefaction and embankment failure has occurred resulting in loss of containment. Hence, evaluation of the effects of earthquakes on embankment dams is a critical design aspect. This paper discusses the methods and the results of a seismic liquefaction assessment and deformation analyses of a tailings dam. The tailings dam consists of a perimeter earth core rockfill starter dam which has been raised using upstream construction methods. The embankment raises (formed by an upstream clay blanket and an all-in rockfill body) are constructed over the impounded tailings, which are potentially liquefiable. Extensive field and laboratory tests were undertaken to assess the liquefaction potential of the tailings, and also determine the material properties required for seismic stability and deformation analyses. Numerical modelling of seismic liquefaction and deformation was carried out using FLAC (Itasca 2016) to predict the magnitude and spatial variation of deformations that may lead to an uncontrolled release of tailings. Primarily based on a parametric assessment of UBCSand and Finn-Byrne constitutive models, the results of the analyses are presented and compared for evaluation.

Jul 1, 2021