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By M Miller

Operators of nickel laterite pressure acid leach and gold pressure oxidation technology frequently employ a series of steam condensing heaters to preheat the leach feed slurry. The heaters are an economic pinch point û although the thermal performance of the heaters is critical to overall process viability and operating cost minimisation, they are also a significant capital item and must be sized accordingly. Despite this, discussions of the factors underlying heater design are conspicuously absent from technical literature, and existing operations feature a conflicting range of heater sizes and configurations. This variety would suggest that at least some of the chosen heater designs are oversized. As part of its detailed design stage, the Ravensthorpe Nickel Project (RNP) constructed and tested a pilot plant heater to develop an understanding of the heating process and to ensure that the RNP heaters were appropriately sized. This testwork used RNP slurry at design density and viscosity on a 450 mm diameter, 6500 mm high column. The pilot plant testwork demonstrated the intrinsic efficiency of the direct steam condensation heating process, which was essentially independent of slurry density and viscosity. Presence of non-condensable gases in the steam phase decreased the heat transferred in certain circumstances, but heater performance remained consistent with thermodynamic limitations. Stagewise heat transfer within the column was rapid, and suggested either a very high slurry surface area or excellent heat transfer within the slurry phase. While the testwork did not set out to distinguish between these effects, physical evidence pointed to droplet formation in the inter-tray shower zone, giving a high heat transfer area. For scale-up purposes, the key facts were that the heat transfer rate was not limited by using high viscosity slurries and heaters could be designed using the principles applied to the smaller of those in existing operations. This paper discusses existing slurry heater designs, the current understanding from open literature, the pilot plant testwork, results and analysis, and scale-up to commercial sized equipment.

Jan 1, 2005

A laminar-flow furnace technique was used to study the combustion of 37-53 µm size fraction of Woodlawn copper concentrate containing 7.4 per cent zinc, 5.0 per cent lead and 22.5 per cent copper. Factors studied included the effect of time, temperature and the distribution of volatile elements between the panicles and the fume. Air was used for most of the work but a few tests were carried out using 1 per cent oxygen in nitrogen. Chemical analysis, X-ray diffraction, and scanning electron and optical microscopy of polished sections were used to characterize the reaction products.When the concentrate was combusted at low temperatures (800-900°C), the fume was rich in lead. At higher temperatures, this was diluled by increasing amounts of zinc and copper. 70 per cent of the zinc, 60 per cent of the lead and 40 per cent of the copper were found in the fume after oxidation at 1400°C. Lead, zinc and copper were present in the fume as anglesite (PbSO4), zincite (ZnO) and cuprite (Cu2O) respectively. The major phases present in the panicles were magnetite (Fe3O4) and/or cuprospinel (CuFe2O4), with some zincite and cuprite.Elemental copper was found in the particles oxidized in 1 per cent oxygen. Possible vapour species responsible for the vaporization are discussed.

Jan 1, 1985

By I Lumsdaine

QNI Pty Ltd operates the Yabulu Refinery located 25 kilometres north of Townsville, North Queensland. The plant treats nickel laterite ores sourced from the Philippines, Indonesia and New Caledonia. The cobalt head grade and overall recovery expectations for the 2001/2002 financial year are 0.161 per cent and 53.8 per cent respectively. Cobalt is a valuable byproduct derived from the nickel refining operation which utilises the Caron Process. Any increases in cobalt recovery that are achieved from the existing relatively low level provide significant improvements to the bottom line of the operation. Towards the end of 2000, a project was undertaken to characterise cobalt losses with the sole purpose of improving cobalt recoveries using a variety of analysis techniques. The Time-of- Flight Secondary Ion Mass Spectrometry (TOF-SIMS û University of South Australia) method was used to verify the presence of surface bearing cobalt species, originating from either co-precipitation or adsorption mechanisms. Cross-section examinations were also performed using Scanning Electron Micrscopy (SEM) and Energy Dispersive X-ray Spectrometry (EDXS). These techniques indicated the presence of high cobalt concentrations (in the order of several per cent) within a select number of roasted and leached ore particles. The phenomenon of cobalt losses due to incomplete leaching within specific ore particles was not widely documented within the Refinery prior to these studies. In order to quantify losses via this mechanism, Mineral Liberation Analysis (MLA û JKTech Centre) was also performed on key samples. This paper serves to document a systematic approach in determining the source of significant valuable mineral losses in an established, operating plant. It discusses the use of a variety of analytical techniques, which have been adapted for the minerals processing industry, but are strongly relevant for plant investigations in the hydrometallurgical industry.

Jan 1, 2002

By Jagger N. D

Lead residue from the Zinc Leach Plant at Pasminco's Port Pirie Lead Smelter was previously filtered on a vacuum drum filter and further dried in a gas fired rotary kiln prior to stockpiling and transport to the Sinter Plant. This process involved several materials handling stages, recycled significant amounts of zinc and often resulted in poor environmental conditions. These problems have been overcome by pumping the thickened leach residue approximately 450m to the Sinter Plant where it is filtered in a Larox Automatic Pressure Filter. The filter cake is discharged onto a conveyor belt, held in a storage hopper and then fed directly to the main sinter plant feed stream. Filtrate is returned to the process for additional zinc recovery. The laboratory and pilot plant filtration results are briefly discussed and compared with the operating plant data. The filter installation and ancillaries are described in detail along with the commissioning, operating and maintenance experience over the past 4 years. This installation has overcome the environmental and materials handling problems and resulted in annual savings of approximately $1 million.

Jan 1, 1989

A new porphyry copper gold district has been discovered at Goonumbla near Parkes in central New South Wales. Endeavour 26 North is the largest deposit known to date with a possible resource of 166.4 million tonnes at 0.74% copper, 0.12g/tonne gold and 1.7g/tonne silver, using a cut-off grade 0.3% copper. Mineralisation is primarily bornite in the higher grade zones and chalcopyrite in the peripheral lower grade zones. Most of the copper, gold mineralisation is associated with potassic alteration. Two mineralised quartz monzonite porphyry intrusive stages have been identified and these are related at depth to a large monz- onite stock which may have been the source of some of the mineralisation. On the basis of detailed paragenesis studies, the potassic zone can be divided into three symmetric subzones. The low grade inner potassium feldspar subzone is confined to the later intrusive porphyry. The outer potassium feldspar subzone is the most highly mineralised alteration halo due to the focussed superimposition of two hydrothermal cycles which have overprinted intrusive and volcanic rocks. The fringing biotite potassium feldspar subzone reveals alteration minerals which are developed early in the paragenesis. Fracture controlled quartz sericite alteration with low sulphide content, fringes and, in part overprints the potassic zone. The restricted pipe-like nature of the alteration zones and related mineralisation suggests that Endeavour 26 North is repres- entative of a multiphase focussed porphyry copper gold system.

Jan 1, 1986

By D Morrison

Backfill is usually considered a necessary evil that contributes little to the principal objective of the operation, ore production. Consequently, it is relegated to an auxiliary role in the operation with minimal equipment and resource allocation in planning and is only superficially considered during feasibility studies. In many mines, the inadequacy of the design and operation of the backfill system ultimately leads to frequent delays, excessive costs and, in the worst cases, major instabilities which result in reduced ore production and lost or unrecoverable ore reserves. The primary objective of backfill is to prevent the progressive deterioration of mined out excavations. With the exception of narrow vein operations, it is too weak to alter the mining induced stress regime and control stress concentrations caused by stope extractions. However, the direct benefits of backfill include the possibility to consider a wider range of mining methods, recovery of 100 per cent of the planned resource and the selection of a stoping sequence that minimises the regional stability problems that cause production shortfalls in the later years of mine production. Indirectly, backfill is a practical means of solving other issues, such as waste disposal, that impact the viability of mining. In Australia, the geotechnical conditions of many mines are becoming more difficult and increased attention to the importance of backfill is warranted. This paper describes realistic aspects of backfilling and the positive impacts a well co-ordinated fill system can have on mining activities as a whole. Examples are presented where an integrated approach to backfill systems have offered significant benefits to the operation.

Jan 1, 1998

A forecast of energy demand in the non-commu- nist world to the year 1990 is presented with com- ments on the expected effectiveness of conservation efforts in achieving more efficient utilization of energy. A forecast of energy supply for the same period is presented showing the contribution of oil, gas, hydropower, coal, and nuclear fuels, with brief comments on the factors constraining the rate of growth of non-oil energy supplies. The role of `synthetic fuels', i.e. liquid or gaseous fuels produced from coal, oil shale, and tar sands, is reviewed with brief discussion of factors affecting the development of this industry. In somewhat greater details, the growth of demand for oil by geographic regions is analyzed. Particular attention is directed to the source of the oil supplies which will be required. The anticipated rate of discovery of new oil reserves is discussed with comments on lead times required in the development of new discoveries in hostile environments such as the Arctic and deep oceans. The continuing importance of oil supplied from countries which are members of the Organization of Petroleum Exporting Countries (OPEC) is illustrated. Oil will continue to be the marginal ('balancing') source of world energy supply throughout the forecast period and although it now appears that oil supplies will be sufficient to balance the energy equation during the 1980s, little flexi- bility will exist to cope with unexpected growth in demand or slippage in supply. Prudent energy re- source management will require major efforts to stimulate conservation and also to stimulate the rapid development of conventional and new forms of energy supplies and changes in energy consump- tion patterns to utilize the new supplies. Because of the long lead times and the massive capital require- ments involved, governmental policies are needed soon which will stimulate conservation and which will encourage businesses to move rapidly to assure the energy supplies the world will require in the 1990s.

Jan 1, 1978

The Pacific Rim countries ofAustralia, New Zealand, Papua New Guinea, Indonesia, Fiji, Philippines and Solomon Islands will be reviewed from an equity investors perspective.   The following areas will be covered: Country risks Exploration spending and activity Project development Taxation Relative cost of doing business Environmental considerations Political/bureaucratic situations Capital raising Equity markets as a source of funds Developing market funds The aim of the paper will be to outline the most attractive areas for investment by equity and private funds plus documenting the changes needed in the less favourable countries if they are to attract investors.

Jan 1, 1995

By D Kepert, C Simpson, D Edwards

Channel iron deposits (CID) currently supply over 40 per cent of the seaborne iron ore trade out of the Hamersley Province. The two well documented producing systems (Robe and Marillana palaeochannels) were both discovered during early reconnaissance mapping principally by BHP Billiton (BHPB) and Geological Survey of Western Australia (GSWA) during the mid 1950s to early 1960s. Both crop out extensively over the majority of their length. Hot on the heels of Fortescue Metals Group 2004 - 2005 discovery of approximately 2.6 billion tonnes (Bt) of undercover iron ore mineralisation in the Chichester Range, the Fortescue Exploration Department turned its attention elsewhere throughout the Hamersley Province. Reappraisal and analysis of publicly available data and ground truthing of developing models led to the recognition of the Solomon palaeochannel system. Subsequent exploration defined a world-class Resource of some 1.9 Bt of iron ore mineralisation of which the great majority is buried CID. Apart from the Marillana CID system, the Solomon region is the only major CID with significant tonnes of sub two per cent alumina CID with over 500 Mt delineated to date. Exploration has also outlined significant supergene bedded and detrital iron ore mineralisation. Ongoing drilling is expected to increase the resource base both in terms of tonnes and confidence. This paper outlines the principal contributing factors which led to the discovery of the Solomon CID and compares its geology with the Robe and Marillana palaeochannel systems.

Jan 1, 2009

Production from a major, deep orebody requires the construction of two 6 m diameter, 1000 m deep ventilation shafts over the next three years. Further ventilation upgrades have foreshadowed an additional 1500 m of 6 m diameter shafts beyond that. After reviewing the construction alternatives it was decided to raisebore the first shaft in one pass using Western Mining Corporation's 121R raiseborer and the Wirth sequential head. The significant cost and speed of construction potential of 6 m raiseboring justified the risks associated with this new technology. Large diameter sequential head raiseboring has only been carried out in South Africa. Over the last three years many lessons have been learnt and the technology has progressed to being considered feasible. Operating practice and the optimisation of raiseboring performance for specific ground conditions are the areas requiring further work. The development of large diameter raiseboring in South Africa and the site preparation and initial operation at Z.C. Mines are described. Comment on actual operating experience includes the geotechnical investigations, the raiseborer foundations, cuttings disposal and the drilling of the pilot hole which has progressed to beyond 450 m. Unforeseen difficulties with the verticality of the pilot hole and with mud losses illustrate the types of problems that can be expected.

Jan 1, 1988

By Armoo K, Tran T

Cementation has been widely used in several hydrometallurgical processes for recovering gold and silver from process liquors. The process is electrochemical in nature, in which gold and silver are precipitated from the solution using less noble metals such as zinc, iron and copper. This paper summarises the current practice of gold cementation from cyanide liquors using zinc powder. Various developmental studies on the cementation of gold and silver from various systems (chloride and bromide) are also reported.

Jan 1, 1991

This paper reviews the role of fill in mining including consolidated fill both histor- ically and currently as determined by a recent survey of the Fill Subcommittee of the Canadian Advisory Committee on Rock Mechanics (CACRM). It covers the application of fill in modern min- ing methods including mechanized cut and fill, undercut and fill, post pillar cut and fill and longhole pillar recovery between stabilized fill. An automated fill preparation plant and recent developments in rotary drilling of hydraulic fill conducting holes are described briefly. The paper also summarizes the findings of some of the important laboratory and field work carried out on the behaviour of fill in Canada, the United States and Australia and again draws on current information obtained from the Fill Subcommittee of the CACRM. Space limitations and unavailability of suitable material prohi- bit the summary of similar information from other countries.

Jan 1, 1973

By G Chitombo

Mass mining methods have become the mining industry’s preferred way of extracting most of the world’s most important metal and mineral commodities. Given the rapidly increasing global demand for commodities, the requirement to increase the contribution of some of these (eg copper and gold) from underground sources also continues to grow. In the case of copper this contribution is needed by a number of major producers to supplement production from their ageing deep open pits. Satisfying this increased demand will require the design, construction and operation of more effective, higher capacity and larger scale mines which, in turn, will require enhanced mass underground mining techniques such as block caving (BC), panel caving (PC) and sublevel caving (SLC).It is now widely accepted that future discoveries of orebodies, which will be developed using these methods, are almost certainly to be much deeper than the deposits presently being mined in this way and made more challenging because of the likelihood that the associated grades may be much lower than currently mined. The design and mining of future large-scale cave mines (supercaves) will become crucial in order to extract full value from such deposits. An essential prerequisite of this will be a much improved knowledge of the deposit, ie Total Deposit Knowledge. In this context, Total Deposit Knowledge is the characterisation of the ore deposit and its surrounds at all scales and includes; rock type (lithology), the spatial orientation of a range of geological features or discontinuities, rock mass fabric knowledge, metal grade and distribution data, geometallurgical data (including alteration), geo-hydrology, permeability and porosity. This is the information that will be used, as now, to delineate geological and geotechnical domains and construct models, but with outcomes superior to those presently available. From this information better-informed feasibility study design decisions and performance predictions must be made. In summary more geological information and analysis is required and this needs to be aligned to potential mining and processing requirements much earlier in the project than commonly occurs.

Aug 22, 2011

By S Agdaca

Leightons is the sole contractor at the Wahana Coal Mine Project (part of the Bayan Group), a multi-seam thermal deposit consisting of 13 coal seams with thicknesses ranging from 20 cm to 500 cm. The average dip of the deposit is 18 - 20°. However the deposit is heavily faulted in certain domains with anticlinal and synclinal structures present causing seams to dip up to 90°. Average thickness of coal inter-burdens range from less than 2 to 12 m. The minimum coal thickness being mined is 20 cm. Coal production is direct mine mouth feed and there is no coal processing plant currently used.Conventional blasting between the highly variable coal horizons in the early phases of the mine life was suboptimal from a production perspective. Drilling short holes with a reduced drill pattern, and on occasions with sloping benches, resulted in low drilling and explosives loading efficiency.A high frequency of small size blasts fired up to two times daily was required with each blast consisting of four up to five small blast areas. Each blast averaged approximately 36 000 bcm thus causing a low utilisation rate of the mining fleet from frequent blast delays and the inability to deploy larger Liebherr 9350 excavators on bench. It was identified that increasing the production targets required a more efficient drilling and blasting process. Furthermore, due to the highly variable nature of the deposit, the existing coal model was determined to not be able to accurately predict the coal seam location prior to blasthole drilling.In August 2009, Leighton Contractors Indonesia and Orica Mining Services with the full support of the Wahana team, initiated through seam blasting trials using electronic blasting systems. Further trials were conducted in November 2009. Trial evaluations indicated that the benefits from decreased lost time events due to blasting, an increased vertical advance rate per blast, and increased overall blast size could be attained while not damaging or diluting coal.Full-scale?through seam blasting has been ongoing since February 2010 for the upper eight coal seams to extract coal seam thicknesses ranging from 20 - 100 cm. This paper will discuss the parameters of the through seam blasting process in Wahana and the resulting benefits to the overall mine production.

Nov 8, 2011

By A Van Kersen, J Hodson

Waihi Gold Mining Co Ltd [WGM], operated by Normandy Mining, has been internationally recognised for its achievements in environmental management at the Martha Mine at Waihi. In a proactive approach to dealing with community concerns regarding blast vibrations on the North Wall cutback, trials were performed using the Cardox System [Cardox], to determine feasibility of achieving economic fragmentation of andesite overburden whilst bettering management levels of 5 mm/s peak particle velocity. Cardox is a non-explosive pressure breaking system which uses high pressure CO2, Results against conventional Ammonium Nitrate/Fuel Oil [ANFO] using a variety of delays showed that conventional blasting techniques could produce marginal fragmentation within the management levels with occasional excursions, whereas Cardox produced the required fragmentation while not registering on the vibration monitoring equipment. Fragmentation to enable normal excavation by a Hitachi EXII00 hydraulic excavator was achieved with a yield of 16m3 per round. The trails indicated that fragmentation with Cardox at the yields required of over 18m3 per round was possible with further product development. The trial demonstrated that non-explosive pressure breaking is feasible and its application warranted where environmental concerns affect the cost-benefit economics of production blasting in sensitive areas.

Jan 1, 2001

By B Mennie, R Poedjono, G Coad

PT Freeport Indonesia operates a large copper and gold mining operation near Tembagapura, Papua (formerly, Irian Jaya), Indonesia. This is a remote location with its own set of unique operational characteristics. The mining and concentrating operations typically produce a concentrate containing 2500 tpd of copper and 6000 oz of gold per day from the combined mining of a 45 000 tpd (ore) block cave operation (DOZ Mine) and a 190 000 tpd (ore) open pit mining operation (Grasberg Open Pit). The Grasberg Open Pit mine will be exhausted in 2015 at which time FreeportÆs operations will entirely underground mining methods. The Common Infrastructure Project (CIP) incorporates the elements required for the shift to underground mining at a production rate approaching 200 000 tpd. The AB Adit portion of the CIP will provide deep level access to the Grasberg Block Cave (below the Open Pit), Kucing Liar, Big Gossan, and the Mill Level Zone orebodies. Commencement of the project was September 2003. The Grasberg Block Cave is planned to start production in 2014. This paper provides details on the project scope, innovative contractual framework, advancement of mining methods throughout the life of the operation, equipment selection, manpower selection, training, geological, and socio-political conditions related to the project.

Jan 1, 2005

The last decade has seen a very rapid development in TBM tunnelling. Some trends are purely technical or economical and others relate more to preferences of different interests. Power levels have more than doubled and thrust levels too. Shield machines are developed to be able to handle harder rock and the open TBMs are made more feasible for `difficult' rock. What is right and what is wrong is more a matter of opinion, but one thing is certain: TBMs now are a useful tool and no longer an experimental work-shop for the enthusiasts.This paper highlights some recent developments and indicates some probable future ones. A few features that have increased the open TBMs' ability to cope with ever harder rock and also to overcome problems with poor rock are discussed in detail, using the Atlas Copco JARVA Mk 27 -the most powerful TBM built so far - as a reference.

Jan 1, 1993

By P J. Vardon, L A. van Paassen, Y Yao, A F. van Tol

Thin-lift atmospheric fine drying (AFD) is a technique used to dewater mine and oil sand tailings, which utilises both self-weight consolidation and atmospheric evaporation. The disposed layers undergo a cyclic drying and rewetting process due to precipitation and deposition of additional lifts on top of the dried layer. The current research aims to optimise the deposition process via use of a numerical model and realistic atmospheric conditions, including both periods of drying and wetting. The model is based upon water balance and includes large strain considerations. A number of material behaviours are characterised using empirical fitting curves based upon laboratory measurement of material characteristics, including both the shrinkage and water retention curves for drying and rewetting. The model is able to model multiple lifts, simulating field scale and realistic climatic conditions within timescales suitable for engineering practice (eg seconds or minutes). The model has been previously validated against controlled laboratory experiments and utilised to simulate field tests. A series of simulations are presented to illustrate the ability of the model to be used as a practical tool for the optimisation of a tailings deposition strategy.CITATION:Vardon, P J, Yao, Y, van Paassen, L A and van Tol, A F, 2015. The use of a large-strain drying and consolidation model to optimise multilift tailing deposits, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 263–270 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

The green field site is one that has no history of mining and as such it presents the designer with a blank canvas, on which any number of drill and blasting options can be drafted. No matter which mining method is selected all technology and experience will need to be acquired from outside sources, applied quickly and produce the right results. North Limited, in joint venture with the Sumitomo Group (20 per cent), have developed AustraliaÆs first block cave mine at Northparkes in New South Wales, Australia. This innovative and large scale mining project was taken from a green field site in November 1993 to a fully commissioned block cave mine in December 1997. NorthparkesÆ Endeavour 26 mine is now producing at a rate of 3.9Mt per annum from a 27Mt ore block. Prior to 1993 no history of mining activity existed at Northparkes. The rock had never been blasted and many questions were raised about how it would behave. While it was clear that the Endeavour 26 (E26) orebody contained geotechnical properties appropriate to block caving, the blasting methods required to establish a block cave mine had never been used in Australia and no designs were available. The joint venture partners had no prior experience with block caving and it was immediately apparent that this blasting technology would have to be acquired from foreign sources and applied to the unique local conditions. Conceptual designs for the block cave drill and blast were first drafted in 1994, first issued for drilling in December 1995 and first blasted in January 1996. 470 km of drill metres and four million tonnes of rock were blasted to complete the undercutting project by September 1997. This paper will provide those developing new drill and blast projects with an inside view of how one small technical team solved many design challenges to successfully construct AustraliaÆs first block cave mine under strict quality controls and ambitious time constraints.

Jan 1, 1998

By K Barns, H Law, T Whebell, P Scobie, T Perkins, J Siliezar, M Larson

With processing a variety of orebodies at Glencore’s Ernest Henry Mining (EHM) has come a changing mineralogy and more complex requirements for treatment in the concentrator. From mid-2013 and into 2014 the grind size required to achieve sufficient mineral liberation for production of a quality concentrate has reduced significantly. What was once a final P80 of 35–45 microns was forced to 20 microns. This has necessitated some creative changes to the flow sheet that previously had a 937?kW Vertimill regrinding a rougher concentrate to 40 microns. EHM is able to utilise an existing M10 000 3 MW IsaMill previously used for magnetite processing, to provide a quick convenient solution without large scale capital expenditures. Operating the Vertimill and IsaMill in parallel in closed circuit was successful at reducing the P80 of the regrind circuit to below 20 microns which increased the final concentrate grade by four per cent. This circuit and intermediate circuits used are discussed. Performance of the Vertimill and IsaMill is compared for efficiency optimisation to improve the overall circuit performance.CITATION:Siliezar, J, Whebell, T, Perkins, T, Law, H, Scobie, P, Larson, M and Barns, K, 2014. From magnetite to chalcopyrite – a story of versatility and efficiency at Glencore’s Ernest Henry mining?operation, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 85–92 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014