Search Documents

By P Vass, C Butler, J Condon, B Hooper

DeGrussa Copper Mine, resource status 10.2 Mt at 5.7 per cent Cu, 2.1 g/t Au (Sandfire Resources, 2013), commenced concentrate production through its 1.5 Mt/a conventional copper flotation processing plant in September 2012. Geometallurgical assessment during the feasibility study identified potential process-critical ore factors that required further investigation to determine potential impact on processing. Ore characterisation and metallurgical processing performance test work of ore types ensued and subsequently, the first quantitative DeGrussa geometallurgy model was born. Now one year into steady state production, the geometallurgical program has evolved significantly from its infancy and provides valuable insight into ore characterisation and behaviour in the processing plant. This paper details geometallurgical investigations undertaken at DeGrussa to date; from feasibility metallurgical test work through to geometallurgical modelling and management practices, as well as reconciliation between observations at feasibility study level and subsequent observations in production.CITATION:Condon, J, Butler, C, Hooper, B and Vass, P, 2013. DeGrussa Copper Mine, Western Australia - feasibility to first production: a case study in developing a working geometallurgy model from first principles, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 59-66 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By Mckenzie CK

Delay scatter, although widely recognised, has rarely been studied with the aim of critically reviewing blast designs. With current trends towards increased deck charging, and the effect on the number of separate delays in blast designs, delay scatter is shown to have a rather profound influence on the control of initiation sequence and the ability to successfully con- duct pre-splitting and smooth blasting. Determination of realistic delay scatter distributions is the first step towards application to blast design. Delay scatter must be evaluated in terms of deviation from the nominal time, not in terms of deviation from the batch mean, since the latter is not usually known without specific testing, requiring accurate timing instrumentation. Computer programs using Monte Carlo simulation can then be developed to investigate the probabilities of out-of-sequence initi- ation or near-simultaneous initiation within any specified interval. The procedures have been applied to both production and development blast designs in Australia and Chile to improve initiation sequence control and to rationalise and simplify blast designs.

Jan 1, 1988

The statistical nature of the variability in detonation times of pyrotechnic delays is discussed, and how to evaluate the probability of required detonation intervals is shown. Some methods (analytical and stochastic) are given for designing blasts to ensure that any adverse effects on the variability in the delays is taken into account and minimised. Using computer models of blasts, detonation simulations can be used to check the initiation sequence for the probability of sequence reversals, indicating areas of high blast damage potential. Charge consumption rates, which relate directly to the resulting vibration levels, can be examined for their susceptibility to variation from delay variability. Models that synthesize vibration waveforms for production blasts, when taking delay variability into account, indicate the difficulty in vibration level prediction.

Jan 1, 1992

Many volcanoes in western Melanesia have tectonic settings and rock compositions that do not conform to conventional models of arc- trench systems. Part of the reason for this may be that in an environment of rapid tectonic change mantle source regions bear the imprint of former subduction even though subduction has now ceased. Results bearing on this concept and on other important aspects of Plelit nesian v ican ism and tectonics, were obtained in 1982-1986 from >e,:eral marine - geoscience studies in the re,,ii n

Jan 1, 1987

By A Guillen, J-P ChilFs

Most 3D geological modelling tools were designed for the needs of the oil industry or detailed mine planning and are not suited to the variety of situations encountered in other application domains. Moreover, the usual modelling tools are not able to quantify the uncertainty of the geometric models generated. The potential field method was designed to build 3D geological models from data available in geology and mineral exploration, namely the geological map and a digital terrain model (DTM), structural data, borehole data and interpretations of the geologist. This method considers a geological interface as a particular isosurface of a scalar field defined in the 3D space, called a potential field. The interpolation of that field, based on cokriging, provides surfaces that honour all the data. The 3D model and its parts are always consistent with the observations. New developments allow the covariance of the potential field to be identified from the structural data. This makes it possible to associate sensible cokriging standard deviations to the potential field estimates and to express the uncertainty of the geometric model. It also, for the first time, gives a statistically optimal, geologically sound way of interpolating geology, other than directly joining the dots as you do with CAD. Practical implementation issues for producing 3D geological models are presented: how to handle faults, how to honour borehole ends, how to take relationships between several interfaces into account, how to model thin beds over many kilometres, how to optimise lithological properties and how to integrate gravimetric and magnetic data. We describe all geology surfaces and volumes using implicit functions. These are then rendered onto the required sections, plans, etc. The estimation of orebody grades and tonnes, using an unbiased and optimal geostatistical technique, makes use of the stratigraphically bound 3D geology model. An application to the geological modelling of the Hamersley iron ore district, Australia, is briefly presented.

Jan 1, 2009

By D Reid, J Black

The adverse health impacts from diesel particulate matter (DPM) exposure are a well-known global concern. The building evidence has triggered underground mining operations to review existing atmospheric conditions and assess the scale of the challenge faced. South32’s Cannington Mine (Cannington) evaluated the ability to provide a healthy atmosphere from a whole mine approach, taking into account existing preventative controls including: maintenance strategies, fuel quality, mining operations, ventilation provisions, monitoring protocols and effective education and training programs.During the evaluation process, Cannington gave due recognition to the advice and guidance provided in the Queensland Guidance Note 21 (QGN21), the Guidelines of New South Wales’ MDG29 and Mining Industry Advisory Committee (MIAC) of Western Australia. Each of these documents advises a dilution rate of >0.06 m3/s/kW is best for reduction of DPM exposure in underground mines.Achieving the prescribed mine ventilation rate typically results in the need to directly invest significant capital into increasing ventilation infrastructure in order to further dilute contaminants. In today’s economic market of volatile metal prices and increasing pressures to meet regulatory requirements, it can become challenging for established metalliferous operations to create a balance between optimisation of current ventilation infrastructure and capital outlay.In order to obtain and correctly justify the requirements for capital investiture Cannington conducted a ventilation operational analysis for the life-of-operation, identifying the existing air volume envelope was adequate for current and future production rates by optimising existing primary ventilation infrastructure through the implementation of a modified ventilation on demand (VoD) and air conservation system.This process achieved sustainable operating and capital cost reductions without compromising delivery of adequate ventilation to work areas. The process also recognised that engaging mine workers’ ownership of their work areas is crucial to maintaining a technically efficient and operationally robust ventilation system.This paper will concentrate on Cannington’s existing preventative controls, their implementation and their management for the prevention of increased DPM exposure; reducing the risk of both short and long-term health impacts to ‘as low as reasonably achievable’ (ALARA).CITATION:Black, J and Reid, D, 2017. Delivering a healthy atmosphere underground in a cost-conscious environment, in Proceedings Australian Mine Vent Conference 2017, pp 159–168 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

Strong markets for metals and energy over the past five years have supported equity and debt market funding to enable a new group of mining juniors to emerge in control of economic resources, some in regions with high investment risk. As companies drive these projects to development, production and positive operating cash flow, their Boards and CEOs are confronting important questions:Having achieved initial success, what is our longer term purpose as a company? Does the purpose originally described in the Initial Public Offering to raise equity remain wholly relevant? Given that purpose, how do we understand the available sets of opportunities and related risks? Should we be acquiring new assets or other companies, or developing the existing portfolio? What commodity sectors and geographies should we focus on? Or should we be conserving funds until asset prices or project costs provide greater assurance of value to shareholders? How do we translate that purpose into tangible goals that shape and direct the work of people in the organisation? How do we get the right work done in the face of high turnover and competition for capable staff? Drawing on the authorÆs career experience and on work undertaken by Heuris Partners, this paper provides a practical CEO framework for strategy development, organisation design and on planning the work of the business in the mining industry.

Jan 1, 2006

Delivery of effective plant shutdowns is primary to the business success of mining and processing plant operations. This paper sets out a methodology that starts with understanding the business objectives of the shutdown and promotes rigorous detailed planning, effective communication, appropriate governance and effective participation of plant operations personnel. The result is delivery of business effective outcomes.

Jan 1, 2004

By A Purchase, C Stacey

The procedure for operation of deluge systems installed in road tunnels is still a subject of debate. The work undertaken in this paper assists in the understanding of the effects of deluge in road tunnels, and thus aims to help inform the development of operational policy. Analysis was undertaken using computational fluid dynamics (CFD) simulations to help explore the deluge interaction with the tunnel ventilation (including smoke exhaust) and combustion products. It was found, for the scenarios considered, that: Deluge activation can decrease the required critical velocity for smoke backlayering, and this in turn can improve the effectiveness of a smoke exhaust system.The dominant parameter for deluge effectiveness is the vehicle configuration, with shielded scenarios (such as a fire in the passenger compartment) showing almost no water reaching the fire. The water delivery rate (5 mm/min versus 10 mm/min) has only a minor effect on the smoke duct damper inlet temperatures and downstream smoke temperatures for small fires (5 MW). For large fires (50 MW) the higher water delivery rate gives slightly improved performance (lower damper inlet temperatures and lower downstream smoke temperatures). A one-dimensional transient tunnel model incorporating different operational and deluge response policies (ie deluge activation times) was developed. It was used to examine the influence of different operational parameters on life safety risk and tunnel damage risk. It was found, for the scenarios considered, that: The life safety risk for different scenarios has a sensitivity to deluge activation policy with the case of delaying the deluge activation for a long time giving the worst outcomes. However, the most critical parameters for life safety risk are operator response time (for all response activities, not just deluge) and the type of fire (configuration, size and growth rate).There is a reduction in risk of tunnel damage when the deluge is activated earlier, although the fire configuration (ie whether or not the seat of the fire can be reached) has the greatest influence on the outcome. It is concluded that the deluge activation policy should be case-dependent. It will depend on the tunnel, the safety systems provided, and most particularly the vehicles involved. The current policy in Australian tunnels is for manual activation of the deluge by the tunnel operator as soon as practical after the fire is confirmed (see also PIARC, 2007). This is a good policy. However, future work may be helpful to improve the skills of operators to make the best judgement as to when deluge should be activated, balancing all risks. This work could include research to further the understanding of deluge and fire in road tunnels, training programs and consideration of historical fire events.

Jan 1, 2008

The role of metals in the economy is discussed with regard to the flow of metals through to final demand and is illustrated by data for seven metals. Factors influencing the changing pattern of metal consumption are described, including relative prices. A des- cription and discussion of current metal demand forecasting methodologies precedes a discussion firstly of broad economic trends and secondly of the evolving pattern of metal consumption relative to GDP (metal consumption intensity), as technology and other factors change and as economies mature. The tendency for metal consumption intensity to plateau and decline when economies reach a certain region of per capita GDP, following a rapid rise early in the industrial- ization process, is shown in comparative data for seven metals and six countries.

Jan 1, 1979

Mineral resource estimation is commonly based on the accumulation of a series of local estimates. At times, the distribution of these grade estimates is not appropriate to the grade distribution of the data on which the estimates are based. Mineral resource grade estimation has an increased potential of being in error as the grade variability increases. As the mineral commodity value increases, greater grade variability within the mineral resource is tolerated. This paper directs its attention to mineral properties where the data average grade is 20 per cent or more than the data median grade at a specific cut-off grade. A mineral resource estimate is enhanced if it is supported by graphs which demonstrate that the sample data have been separated into appropriate geological domains. Each geological domain has a unique grade distribution signature, which can be graphically demonstrated simply and objectively. This signature will usually be evident well before the Indicated mineral resource estimates are available. The paper looks at the use of the log probability and MedAve plots to assess how effective domaining has been. It further outlines how the MedAve plot can be used to assess the integrity of the mineral resource grade estimate within a geological domain with the data on which it is based. The paper suggests that the overall grade of a mineral resource at any cut-off grade will be closer to the data median grade rather than the data average grade. Tips are provided to ensure that the odds reflected in the data grade distribution are not ignored and hence the risk that the project is affected by unrealistic estimates of the overall mineral resource grade is reduced.

Jan 1, 2003

By P A. Grossman, J H. Rubinstein, M Brazil

The installation of truck turntables at above-ground crushers has the potential to yield gains in efficiency and productivity by eliminating the need for the trucks to turn around and reverse up to the crusher to dump their loads. The benefits include savings in time, fuel consumption and tyre wear. In addition, having a smaller area near the crushers dedicated to manoeuvring the trucks can be a significant benefit at some sites. Safety is also enhanced using turntables.This paper describes a project with the Australian Turntable Company to develop software that generates near-optimal layouts for the paths taken by the trucks in the vicinity of the crushers when turntables are present or absent. The geometry of the paths is constrained by the turning radius of the trucks and by the boundary of the manoeuvring area. The software quantifies the benefit of installing turntables by generating a design for paths with turntables and comparing it with the layout in current or planned use by the mining company. Through the use of this software tool, a mining company can readily assess the benefits of using turntables at their site.CITATION:Brazil, M, Grossman, P A, Rubinstein, J H and Thomas, D A, 2014. Demonstrating efficiency gains from installing truck turntables at crushers, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014, pp 259–266 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By Croggon R

Passing a direct current through a jointed fine grained soft rock mass auses the movement of water by the process of electric-osmosis. There are other processes such as electrolysis which transport ions that interact with associated ions and can, in turn, be oxidised. This results in the dissolution products being transported towards the cathode electrode. In the cathode region the ferrous hydroxide is oxidised to ferric hydroxide %%ith consequent precipitation. The cracks and joints are current pathways, along which the ferric hydroxide is deposited. This deposition reinforces the joints and increases the shear strength. By adding calcium chloride to the anode, the rate of corrosion is increased with the concomitant increase of deposited ferric hydroxide along the joints. This, in turn, significantly increases the joint shear strength. The process is pervasive in that the current via the water paths travels through the crack and joint systems The result is that not only specific joints are reinforced but the cracks and mtciconnected voids are also reinforced.

Jan 1, 1997

Demonstration of Solid-Liquid Separations Using Recycled Supernatant that Contains Temperature-Responsive Polymer The effective use of recycled supernatant that contains temperature-responsive flocculant is demonstrated for solid-liquid separations. The recyclability of poly(N-isopropylacrylamide) (PNIPAM) of several different molecular weights and a 15 per cent negatively charged derivative are compared. Batch settling tests of a-alumina suspensions are first conducted at 50¦C, with a subsequent 25¦C period, after which the supernatant is harvested and used to flocculate subsequent suspensions. Using this procedure consecutive separations are obtained with the repeated recycling of uncharged PNIPAM containing supernatant. Batch settling tests indicate that hindered settling rates increase with molecular weight of PNIPAM. Adsorption studies indicate that strong adsorption of PNIPAM onto alumina occurs with PNIPAM at 50¦C and that significant desorption occurs after cooling at 25¦C. However, the extent of desorption decreases with molecular weight resulting in low amounts of PNIPAM for recycling and poor settling behaviour when high molecular weight PNIPAM is recycled. Little recyclability was evident using the negatively charged PNIPAM. On the basis of these findings a recycling-thickener apparatus that uses low molecular weight uncharged PNIPAM is proposed.

Sep 13, 2010

The purpose of this paper is to explain the basic structure of how minerals are marketed, whilst highlighting the essential factors that mine management needs to be confident are incorporated into a mineÆs marketing strategy. The traditional mine management approach to marketing has been to defer its scrutiny to the marketing manager and take a largely passive role. It is this paperÆs assertion that mine management needs to become more proactive and provide greater strategic input into the marketing process. Irrespective of what mineral your mine produces, the key marketing principles remain constant and need to be understood and managed to extract the full benefit on behalf of the mining asset. From a mine management perspective, success is ultimately linked to understanding these marketing principles and ensuring that they are effectively addressed by your mineÆs marketing strategy. This paper will unashamedly attempt to simplify marketing by explaining how the basic fundamentals of supply and demand set market direction, the importance of a comprehensive marketing strategy, the importance of customer relationships and how contracts and prices are typically negotiated. This paper will use examples from the metallurgical coal (met coal) industry to highlight these points. The paper will also provide a template for developing the critical mine interaction that needs to exist between the marketing department and management to develop a æwhole of mineÆ approach to marketing. It is this core group that will be strategically responsible for delivering the commitments your mine has made to your customers. For mine management not to be actively involved in this process puts at æriskÆ the hard won production and cost efficiencies achieved at your mine and ignores the opportunity to maximise your current and future revenue streams. And whilst this paper recognises that is arguably unreasonable for mine management to become æmarketing expertsÆ, it also argues that it is unreasonable for a mine management to divorce themselves from the process.

Jan 1, 2006

By Grady B. V, Ault A. R, Newman O. M G, Fraser R. J, Malcolm J. McPhersqn

In all electrolytic zinc plants cadmium is removed as an impurity prior to the zinc electrowinning stage of the process. Cadmium metal is the favoured form of this by-product and most plants use an electrolytic route for its production. The formation of dendrites in cadmium electrowinning processes is the major limitation to deposition rates. There is an economic incentive, therefore, to better understand the factors affecting their growth. A technique that has been used by others to examine fundamental aspects of dendrite growth has been applied to industrial strength electrolytes. It involves potentiostatic deposition in a cell containing the electrolyte of interest. The variation in the current with time at a given overpotential allows the determination of the dendritic growth induction time. A method was developed (the Locus method) from the investigation of a set of such potentiostatic curves, obtained over a range of applied overpotentials, that appears to give a measure of electrolyte quality with respect to dendritic growth in galvanostatic deposition. The Locus technique predicts that zinc at industrial concentrations in cadmium electrolytes should have a significant effect on morphology and that deterioration of morphology will occur as the zinc concentration in the electrolyte is increased. This effect is consistent with literature prediction and was shown to relate to a reduction of the diffusion limiting current density. Magnafloc R333 is used as an additive at Pasminco Metals-EZ to control the morphology of cadmium deposits and the Locus method was successful in predicting its dendrite inhibiting properties. A possible mechanism is discussed. This work has opened avenues for future research with respect to a technique that may have an industrial application in electrolyte characterisation and has pointed to a direction in which better understanding of galvanostatic dendritic growth may be found.

Jan 1, 1993

By I Grewal, M Lundt

Dense medium separation (DMS) is one of several preconcentration methods used for early waste rejection from run-of-mine ores at relatively coarse particle sizes prior to additional milling and beneficiation. DMS has been used extensively in the coal, diamonds, mineral sands, base metals and iron ore industries to produce either a final product or as a preconcentration step. Laboratory scale and pilot test work at the Met-Solve laboratory in Canada has demonstrated successful separation and upgrading of other minerals such as lead, zinc, copper and lithium based ores using DMS.This paper reviews historical dense media systems, results from the pilot-scale multi-stage DMS Separator “Condor” system, as well as production plants and associated laboratory heavy liquid separation (HLS) test work on various minerals. The mineral systems tested included a lithium bearing ore and a fluorspar ore. Other minerals were tested but are not reported in this paper.Pilot plant test work on a fluorspar ore showed that 41.6% of the mass could be rejected to the tailings stream while 95.3% of the CaF2 was recoverable to the product stream. On a spodumene sample that was tested, it was possible to reject 55% of the mass to tailings while recovering over 90% of the lithium.In recent market conditions and with the decreasing grades in existing ores, preconcentration should be a consideration to maximise the value of certain operations.CITATION:Lundt, M and Grewal, I, 2017. Dense media separation – a valuable process for preconcentration, in Proceedings MetPlant 2017, pp 122–130 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

The Mt Newman Beneficiation Plant uses a combination of heavy media deans, heavy medium cyclones and Reichert cones to produce saleable iron ore concentrates from low grade iron ores. The aim of this paper is to discuss score of the changes that have been made to improve the operation of the heavy medium circuits.

Jan 1, 1987

Many metallurgical beneficiation and primary concentrating processes rely upon discrimination of products from gangue based on particulate density of the different minerals and combinations of minerals in an ore. The basic definition of density is simple, but the apparent density that minerals exhibit when in the environment of commercial densimetric separation processes is more complex and is ill-defined. Measurement of the apparent density displayed by minerals in their separation situation is essential if modelling of plant performance is to be meaningful or when comparison of an existing operation with a æperfectÆ separation constitutes a part of an audit or of a plant control function. Seven methods of dividing ore samples into discreet density fractions are examined and criticised in this paper. The shortcomings, difficulties and potential errors arising from the use of each method are evaluated. Most of the techniques described have been used by the author and generally their faults are understood and the resultant first-hand experience has been used to overcome these faults. A simple new computer-assisted technique for developing meaningful densimetric data is described.

Jan 1, 2004

By Hall ST, Miles NJ

Recently an inorganic salt, sodium polytungstate (SPT), has become available that allows the preparation of non-toxic solutions of relative densities up to 3.1. It is relatively expensive and at the higher relative densities achievable, highly viscous. Alternative inorganic compounds may in the future be identified that overcome these limitations. The Australian Mineral Industries Research Association Ltd (AMIRA) has initiated a project to examine possible alternatives. However, it has been found that by the addition of finely divided ferrosilicon to solutions of SPT, relative densities of up to 4.0 can be achieved. A laboratory technique for density fractionation of sized mineral samples utilising this finding has been developed. This is currently being extended to study the potential applications of such liquids and suspensions in dynamic systems for mineral, coal and recycled waste separations.

Jan 1, 1993