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By T Baumgartl, M Edraki, L Huang, D R. Mulligan

"Phytostabilisation with tolerant plant species has been advocated as a cost-effective solution for sustainable cover of tailings from metal mines and bauxite refinery. The development of sustainable plant ecosystems on such wastes requires not only tolerant plant species compatible with local climatic conditions, but also the formation of stable and functional root zones through systematic processes to develop functional soil matrix and horizons (eg A-B-C). However, the process requirements for reconstructing functional root zones in tailings are poorly understood. Based on a review of current literature and industry experience in tailings revegetation, the present paper conceptualises three key phases in the process of root zone development in amended tailings: hydro-geochemical stabilisation resulting from the interactions among tailings characteristics, amendment measures and local climatic conditions the rehabilitation of soil biological capacity the establishment of ecological (carbon and nutrient) linkages between the rehabilitated root zones and the above ground plant communities.Key research is required on: the relationship between hydro-geochemical stability and mineralogy and geochemistry of tailings, in response to rehabilitation treatments under local climatic conditions the relationship between soil biological capacity and hydro-geochemical stability in the root zone the transition of soil microbial communities specific to exogenous organic matters into those required for mineralising litters of in situ plant communities.CITATION:Huang, L, Baumgartl, T, Edraki, M and Mulligan, D R, 2012. Sustainable phytostabilisation of mine tailings - A critical analysis of system requirements and approaches, in Proceedings Life-of-Mine 2012, pp 105-116 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 10, 2012

By C S. Kelsey, J R. Kelly

Australia is presently enjoying the fruits of a booming iron ore market. Expectations are that market strength will be supported in the short to medium term by increasing feedstock demands from steel mills, as world economies rebuild post-Covid-19. However, as cost and environmental pressures increase the longer-term market outlook will be dominated by product quality. The ‘flight to quality’ will place increasing demands on direct shipping ore miners as they compete to maintain their standing in the iron ore marketplace. China will progressively disengage from its dependence on Australian imports, leaving miners under increasing pressure to boost product quality and diversify outlets globally. Australia has vast deposits of low-grade magnetite ores located mainly in remote and arid regions of the continent. This paper proposes a dry grinding and magnetic separation process to produce premium concentrate grades from the low-grade ores, to assist in meeting future product quality demands. The premium grade concentrates could be either blended with lower quality direct shipping ores or marketed separately. The proposed dry concentration process involves the pairing of Vertical Roller Milling (VRM), a mature technology widely used in the cement industry, and Planar Magnetic Separation (PMS), a new methodology, which has been developed to the threshold of commercialisation by the private Australian company Cyclomag P/L. Two laboratory prototype planar magnetic separators with field strengths of 1800 gauss and 6000 gauss have been built and tested on a range of magnetite ore types over the past three years. In each case, following grinding to liberation sizes, a combination of roughing and cleaning operations has produced pellet grade concentrates. Vertical roller milling has competed successfully with conventional media milling in grinding cement clinker, limestone and blast furnace slags. A key advantage of dry VRM/PMS processing is its potential adaptability to stepwise modular development, which can minimise initial capital investment, while generating early revenue streams to cope with unpredictable market volatility.

Nov 8, 2021

By J G. McLellan, B Miller

Copper and Gold mineralisation at the Ernest Henry deposit is bound by two controlling shears along the hanging wall and footwall margins. The shear zone geometries have been influenced by a large diorite intrusion, dated at ca. 1660 Ma, which lies to the north-east and south-west of the main orebody. The shear zones, which partitioned strain prior to the main mineralising event ca. 1514–1504 Ma, and in conjunction with adjacent regional structures, have been a critical factor in the deposit location and geometry. Conventional exploration techniques have been utilised proximal to the current deposit since the initial discovery in order to expand upon known resources, with limited success. However, new geomechanical modelling techniques have now been employed to target structurally controlled mineralised zones in three dimensions. The main aim of the geomechanical modelling was to simulate the effects of regional deformation events to highlight areas of anomalous strain, which indicate areas with a higher likelihood of fluid focusing and mineralisation potential. This project was focused on testing the latter stages of a D3 event (NE-SW compression) to examine preconditioning of the system, and a D4 event (SE-NW compression) which have ultimately been responsible for the current location of the mineralisation.CITATION:McLellan, J G and Miller, B, 2017. Geomechanical modelling of the Ernest Henry iron oxide copper gold deposit – identifying fluid pathways to predict potential mineralised zones, in Proceedings Tenth International Mining Geology Conference 2017, pp 75–82 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By M Gwynne

McArthur River Mine is located approximately 50 km south-east of the NT township of Borroloola and approximately 120 km from the Gulf of Carpentaria. The mine hosts a series of layered shallow dipping tabular orebodies, with current reserves of approximately 22 Mt, grading 13.6 per cent zinc, 6.3 per cent lead and 65 g/t silver. Owing to economic considerations, the lower most orebody (No 2 orebody) has been selected for initial mine production. Following the completion of the No 2 orebody, mining will transfer to the lower grade and metallurgically more complex No 4 orebody. The mine employs a total of 235 people throughout the underground and surface areas. The majority of the workforce work a fly-in/fly-out, seven-day- on/seven- day- off roster with 12-hour shifts. Presently, a further 18 contractors are involved in trial mining areas. An apparent dip room and pillar technique has been selected as the primary mining method. Officially opened in September 1995, the current production rate of 1.2 Mt per annum will eventually escalate to 1.5 Mt per annum. Though most production is achieved through the use of conventional loaders, trucks and jumbos, the recent development of methods utilising scrapers, hand held machines and modified jumbos has produced encouraging results in steeper dipping areas of the mine. Initial production has been hindered by several factors including extensive and largely unpredictable faulting, worse than expected ground conditions and difficulties with some mining equipment. Compounded by the relatively thin 3 m ore seam, initial mining resulted in high dilution and poor production. This paper describes the development of unique planning and production systems that were evolved in order to overcome these problems and achieve the targeted production rates and head grade.

Jan 1, 1998

By J McCluskey, N Barros

"Long-term strategic planning at BHP Billiton’s Western Australia Iron Ore business aims for sustainable value maximisation of its large, long-life, low-cost, expandable mineral inventory and supply chain infrastructure. While mine plans are key components of this value equation, this objective requires a whole-of-business approach through comprehensive consideration and optimisation of the full value chain. Only through a system view do we believe that the value proposition of a set of plans is truly optimised.The fundamental considerations include: mineral inventory information, given its intrinsic uncertainty and risk/knowledge horizon a marketing view of future quality premium/discount based on overall market quality load whole of supply chain optimisation on a throughput accounting basis alternative sequences of capital decisions closure costs with significant magnitude of total movement requiring optimisation as part of the plan. In addition, the plan provides a view of acceptable uncertainty levels at different times in the future.BHP Billiton Iron Ore uses a structured Life of Asset planning process that supports the business with the optimisation of its maximum value proposition through a non-deterministic scenario-based optimisation approach on an annual basis. This is a key input to each year’s medium-term plans and budgets, including activities identified through a value of information approach that resolve the key uncertainties and steadily improve confidence in the plan.CITATION:McCluskey, J and Barros, N, 2014. Life of asset planning, uncertainty and value optimisation of the iron ore business – from exploration, to market, to closure, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014, pp 33–40 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 24, 2014

A Good Product Range - So What! While in terms of water, waste management and environment protectrion, the Gippsland Basin may appear to have a good product range, what does this really mean? What it means is that, like any product range, the virtues of the product range must be sold and accepted by a majority of the public. The social, economic and environmental benefits of any enterprise using these products must be sold and accepted by the regional population. Many a budding entrepreneur has failed because he assumed that the public would accept his product, so good did it appear to be! However, we know that such an assumption must be avoided and that a great deal of time and effort needs to be invested in promoting and gaining acceptance of a product to ensure a long term and viable market.

Jan 1, 1992

The plant and processing site at Porgera has been built on a levelled mudstone ridge about lkm E of the mine. Excavation of 7xl06m3 of soil and rock was necessary to achieve the required area. The exposed mudstone belongs to the Chico Formation and is weak, sheared and readily breaks down by slaking upon exposure. Tectonic uplift and subsequent erosion have produced the present landscape of narrow bedrock ridges, with deep colluvium in the incised valleys. The deep excavation to a maximum of 60m, has rapidly unloaded the mudstone, and subsequent stress relief has caused rebound and dilation of the material. The processes of pore pressure equilibration, softening, progressive failure and loosening, combine to deteriorate the newly exposed rock mass. These processes are commonly associated with pre-existing shear surfaces, fissures and a

Jan 1, 1991

In the last 40 years nuclear energy has taken its place as a major source of electricity worldwide. It now produces 17 per cent of the world's electricity and could conceivably produce a higher proportion, to displace some six billion tonnes of carbon dioxide emissions per year. Concerns about global warming and environmental quality now underline the virtues of nuclear electricity among alternative sources of energy. Global electricity demand is rapidly increasing as a proportion of total energy usage. The proportion has doubled since 1960 and the demand is expected to increase at least 75 per cent between now and 2020. The source of this extra capacity, and the replacement of present capacity, raise questions with major resource and environmental implications. Today nuclear energy is a mature technology. Over 1200 nuclear reactors have been built and operated, some of these have been decommissioned, and among the 440 reactors in commercial operation the first advanced reactors are now entering service. Some 8000 reactor-years of operation have, with the sole exception of Chernobyl, shown nuclear energy to be extremely safe and reliable. High-level wastes are being managed properly and in different parts of the world two strategies are applied to this. Australia has a major role as a long-term supplier of uranium, since it holds almost 30 per cent of the world's reserves. This, along with an impending sellers' market for uranium, is making it an opportune time to develop new mines here. However, after several decades of concern about civil nuclear energy contributing to the arms race, we now have uranium liberated from nuclear weapons stockpiles being diluted for use in civil reactors, which will supplement ex-mine supply. The public acceptability of nuclear energy remains the critical factor in its future and hence in ours.

Jan 1, 1997

By G Harbort, D Zoetbrood

"The Phu Kham copper-gold operation in the Laos People’s Democratic Republic (PDR) is owned and operated by Phu Bia Mining Limited. PanAust Limited holds a 90 per cent interest in Phu Bia Mining Limited, with the remaining ten per cent held by the Laos PDR Government.The original 12 Mt/a copper-gold concentrator at Phu Kham commenced production in April 2008. An incremental improvement program resulted in a number of circuit changes being incorporated by 2011, including conversion of conditioning tanks to flotation cells and the installation of a Jameson Cell cleaner scalper. In 2012 the Phu Kham Upgrade Project was commissioned to increase throughput to 18 Mt/a. In April, 2013 the Phu Kham Increased Recovery Project was commissioned to maximise performance by debottlenecking the plant IsaMill™ regrind and cleaning capacity.With the variable mineralogy of Phu Kham ore, control of the c concentrate regrind circuit is essential in terms of achieving effective liberation to maintain concentrator performance. On a routine basis laboratory regrind signature plot data is compared with daily surveys of the operational IsaMills™. More extensive surveys are also conducted to determine size distribution on a mineralogical basis and the effect of fine regrinding on pulp electrochemistry and flotation performance. This paper provides a review of the operating performance of the Phu Kham IsaMills™ with regard to power draw, feed and product size distribution, feed per cent solids, mineralogy and pulp electrochemistry. Operating performance is compared with the IsaMill™ signature plot test for predicting performance.Citation:Harbort, G, Zoetbrood, D and McNab, B, 2016. Operating Performance of the Phu Kham IsaMill™, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 39–50 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By A Rantala, J Timperi and J Kaartinen, T Maksimainen, O Haavisto

"X-ray fluorescence (XRF) is the most common technique used for online slurry assaying in base metal flotation applications. Typically, assays from feed, concentrate and tailings slurries are used to monitor and control the flotation circuit, with possible additional sampling locations in other main slurry flows inside the circuit. The elemental content detection from the XRF spectrum is relatively straightforward as the spectrum contains element-specific peaks whose height corresponds to the element concentration in the sample. However, centralised XRF analysers measure the elemental concentrations line-by-line, which may increase the sampling interval for an individual line and cause unnecessary response delays, especially in large flotation plants. Reflectance spectroscopy is an emerging technique that can be used to obtain more frequent measurements from slurries. The measurement is based on the mineral-specific absorbance of light in the visible and near-infrared (VNIR) wavelength range. Due to this relatively inexpensive and simple measurement system, it is possible to conduct the measurement simultaneously in several slurry lines. However, the information contained in the VNIR spectra is more difficult to interpret as concentrations of all the minerals in the sample contribute to the measured spectrum and changes in solids content, particle size and mineralogy disturb the elemental content estimation. Therefore, frequent calibration of the measurement is required. This study presents the application of combined reflectance spectrum and XRF measurements for rapid online slurry assaying in a copper-nickel flotation plant. The XRF assays are utilised as calibration samples for the reflectance spectrum measurement, keeping the calibration model up-to-date. The rapid reflectance spectrum analysis is then used to provide an almost continuous estimate of the slurry contents, enabling further improved process monitoring and control.Citation:Haavisto, O, Maksimainen, T, Rantala, A, Timperi, J and Kaartinen, J, 2016. Reflectance Spectroscopy with X-ray Fluorescence for Rapid Online Assaying in a Copper-nickel Flotation Plant, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 85–92 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By L Ventura, M Almond

The Pueblo Viejo project in the Dominican Republic installed an innovative sample system on its reverse circulation (RC) drilling rig during commissioning and subsequent commencement of operations. As knowledge of the orebody increased with mining and plant production, cost pressures became apparent that raised questions concerning the continued use of RC drilling versus blasthole sampling for ore control.To justify the continued use of RC drilling for grade control, an in-depth study was undertaken to determine the quality of the sample and prove its value-add to the operation.To investigate the differences in sample quality, a complete bench trial was initiated across both ore pits to compare RC drill results with blasthole assays on a side-by-side basis. The results indicated that based on ore block comparison between RC and blasthole sampling, RC identified an additional 20 per cent of high-grade (+ 4.5 g/t Au) ounces.Previous work indicated that Au, Ag and Cu were all elevated in the drill fines at Pueblo Viejo (Goers and Almond, 2012). This previous test work did not consider the quantity of fines in an RC sample therefore new test work was undertaken to include particle size distribution analyses. This study would determine if the inclusion of fines in the sample was occurring and compare the quantity of fines in the sample against other sample systems and blasthole samples.Comparisons between RC samples and blasthole samples indicate that for the RC samples a range of 30–35 per cent of the sample passed 300 mesh as compared to blastholes where the range of the sample passing 300 mesh was 15–30 per cent.This paper includes a case study on the importance of accurate samples and how they have impacted throughput through the pressure oxidation process plant at Pueblo Viejo. The accurate samples provided by RC allow for improved stockpile and blending strategies, showing the importance of accurate samples to manage risk and create value, against the perception that savings can be made at the risk of poor sampling performance.CITATION:Almond, M and Ventura, L, 2017. Adding value with reverse circulation drilling at Pueblo Viejo, in Proceedings Tenth International Mining Geology Conference 2017, pp 277–284 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By A Bennett, A Peck

BHP has recently constructed a Hot Briquetted Iron Plant at Port Hedland in the Pilbara region of Western Australia. Supply of iron ore fines to the plant is by conveyor from the companyÆs existing Nelson Point stockyards. The conveyor passes under Port Hedland harbour in a concrete segmentally lined tunnel, approximately 1030 m long and with a 5.1 m external diameter. The tunnel was constructed by a Tunnel Boring Machine (TBM) which both excavated the ground and erected the tunnel lining. The tunnel was bored between cut and cover in situ concrete portal structures, the TBM being launched from the Finucane Island side towards Port Hedland town. The alignment required lengthy gradients of 1:6 on either side of the harbourÆs dredged channel, under which the tunnel is bored with a minimum clearance of 8 m.The tunnel is fitted-out with:1800 mm belt conveyor capable of 10 000 tph;walkway along which a specially designed inspection/ maintenance vehicle can run; andtunnel services including power, light, fire detection and suppression communications, water mains for wash down and sumps and pumps for drainage.This paper gives a general overview of the design and construct contract, important aspects of the design and the construction process itself.

Jan 1, 1999

By A Hollweg, K H. Esbensen, M Lischka

Two new splitter designs for intercepting moving streams of matter are presented, the variable cross-stream splitter (vCSS) and the rotary stream splitter (RSS), which are intended for implementation in a fully automated modus. The vCSS facilitates obtaining up to three subsamples with different splitting ratios from automated laboratory flow paths, while the RSS divides the intercepted sample into 16 equal analytical aliquots. The splitters can process a wide range of dry, granular and free-flowing materials (<5 mm). The required weight for each subsample can be set without mechanical adjustments in the case of the vCSS. Typical applications are subsampling/splitting for X-ray fluorescence pelletisation (or fused beads) or splitting for average shift composite sampling or grain size analysis. The vCSS combines the advantages of riffle splitting (three user-defined subsample masses) with miniature bed blending and can accept up to 15 kg in total incoming sample mass. In practice, the automated vCSS can deal with unlimited ingoing mass fluxes, while the RSS is designed to operate at a user-defined fixed subsampling rate (1/16th in the tested version). Both splitters have the potential to be optimised and evaluated according to an application/user-defined total sampling error (TSE) + total analytical error (TAE) threshold. Both splitters were tested under adverse conditions and with compositions involving three components with properties representing typical mass fluxes and components concentrations in industrial and technological systems: phosphate concentrate 89.00 per cent (<500 µm), slag ten per cent (>2 mm) and glass spheres one per cent (750–1000 µm). The slag particles vary widely in particle shape, aspect ratio and surface roughness, while the glass spheres are extremely prone to bouncing and segregation (spillage). This test system is extremely difficult to split and thus constitutes a realistic worst-case scenario. While the vCSS does not comply strictly with Theory of Sampling demands for correctness, both splitters may well be able to deliver fit-for-purpose representative results if/when tested properly. Average relative mass deviations ranged from 1.89 per cent for phosphate concentrate (relative standard deviations of 20-fold repeated splitting) to 4.72 per cent for glass spheres and 13.04 per cent for slag. For the RSS, the average replication experiment splitting variation was 2.89 per cent for phosphate concentrate, 4.82 per cent for glass spheres and 11.1 per cent for slag. Both new automated online splitters would therefore appear to be able to be tuned to fit-for-purpose representivity (defined here as maximum relative reproducibility <5 per cent) for many non-extreme materials; however, it is always imperative to test every new type/class of material empirically. There is a wide commercial potential for important materials and commodities sectors, including food, feed, drugs (pharmaceutical), secondary raw materials, recyclates, agricultural products and seeds.CITATION:Lischka, M, Hollweg, A and Esbensen, K H, 2017. New online/atline splitter designs for laboratory automation – feasibility results, in Proceedings Eighth World Conference on Sampling and Blending , pp 159–166 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By S C. Dominy

Current and proposed methods of resource classification relate to the geological, economic and technical confidence in the estimated resource. Geological confidence is, however, only vaguely defined. It is largely related to the level of drilling and sampling, to the geologistÆs perceived level of confidence in his/her work and on the continuity of the mineralisation. Rarely has any real attempt been made to assess how well a deposit has been explored, sampled and evaluated and how accurate or realistic the geological model is for the deposit. This contribution reviews the impact of two of the potential sources of error, ie sample recovery and quality. The first of these parameters is measured during logging and assaying, but is often forgotten during grade and tonnage estimation, and resource classification. Preliminary studies have shown that modelling of this parameter is a valid exercise, which should accompany the evaluation of grade and other economic parameters. The sample recovery factor for an ore block can then be used to reassess the confidence in the block. It could, for example, downgrade the status of a Measured Resource to an Indicated Resource even though standard methods might indicate that the higher classification is applicable. A method is proposed by which this recovery factor could be incorporated into current resource classifications producing a more sophisticated and comprehensive measure of sample quality. A review of the sources of error naturally leads to the assignment of scores to each stage of the evaluation process, depending on the methods used and assumptions made. Sample recovery is one important factor, which is likely to appear at several stages. These scores can then be weighted and combined in a manner resembling that used in the CSIR Rock Mass Classification. This score will then allow the resource estimate to be rated on a scale from 0 to 100 per cent to produce a Quality Control Index (QCI). However, this index must then be modified using an Evaluation Difficulty Index (EDI), which reflects the difficulty of a particular style of mineralisation to accurate resource estimation. This results in the production of a Resource Reliability Rating (RRR), which can then be linked to international classifications, such as the 1999 JORC; 2000 CIM; and 2001 EURO codes. This will permit a more precise definition of geological confidence levels or, combined with estimation error, produce a classification system in its own right. This same rating can also be used as the basis for technical audits of mineral projects.

Jan 1, 2002

By B Watson

The ConSep ACACIA Reactor is a device, which utilises a high intensity cyanidation process to achieve very high, usually near total, recovery of gold from gravity concentrates. The process utilises a fluidised bed and a chemical oxidant to enhance the gold dissolution kinetics to the point where the bulk of the dissolution occurs in a few hours. For convenience and security, most plants operate a 24-hour turn around. The product from the process is in the form of cathode gold ready for smelting by traditional means. The ConSep ACACIA Reactor performs a two-fold role. Firstly it increases gravity gold production, leading to a decreased CIP feed grade. Secondly, it removes slow leaching components from the plant leaching circuit. This two fold benefit leads to the following efficiencies: enhancement of the dissolution kinetics; enhancement of the adsorption kinetics; reduction of the gold load reporting to the carbon; a significant reduction of the ægold in circuitÆ lockup; and removal of slow leaching entities which can also result in a lowering of the required cyanide concentrations in the leaching circuit and a subsequent reduction in overall cyanide consumption. The above benefits are discussed in this paper, with a particular focus on the ConSep ACACIA ReactorÆs role in removing slow leaching components, with data generated over a 21-month period. Improvement in overall plant recovery via removal of slow leaching gold species is achieved in two ways. Firstly, some of the slow leaching entities, successfully leached under intensive cyanidation, are not always fully leached under plant conditions. This results in a lowering of the solid tailing. Secondly, the faster leaching kinetics achieved in the plant as a result of the removal of slow leaching entities results in faster and more complete adsorption of the dissolved gold onto activated carbon. This results in a lowering of the solution tailings. The construction and operation of the ConSep ACACIA Reactor is simple. Apart from the reactor body, which is a proprietary design, all components of the system are æoff the shelfÆ or specific to the siteÆs requirements. In operation of the fully automated version, a PLC controls a series of valves and pumps but except for a daily changeover process the only operating component for the bulk of the time is a relatively small solution pump. The process can be totally automated giving the security of a æhands freeÆ concentrate handling process up to the point where the product is presented as cathode gold. The ConSep ACACIA Reactor was developed by Anglogold Australia (formerly Acacia Resources) for Union ReefÆs Gold Plant and has been in production since February 1999. It has proven to be a low cost, high recovery, mechanically reliable method for the processing of gold concentrates. Such has been the success of the plant, as of June 2003 there are eighteen full installations of the processing plant installed at mines owned and/or managed by Anglogold, Newmont, Placer Dome, Independence (formerly Lonrho), Sons of Gwalia and Harmony.

Jan 1, 2003

By R Godard, J Gantumur, F Prince, C Pascoe

Resolution Copper Mining LLC (RCML) is one of the largest undeveloped high-grade porphyry copper-molybdenum deposits in the world, with an orebody at depths of approximately 2000 m beneath post-mineralisation cover. With a vision to develop a large-scale, low-cost operating mine, the project is designed as a micropanel cave with an advanced undercut.In September 2014, RCML began a study focusing on identifying and selecting the best production cases to eventually reach full production (120 kt/d). To achieve this, a methodology was developed that allows the fast evaluation of a large number of production schedules.Dassault Systèmes GEOVIA was commissioned to enhance the Footprint Finder program for batch scheduling panel cave production. The tonnage and grade schedules produced by Footprint Finder were compared to schedules developed using personal computing block caving (PCBC™). The inputs to Footprint Finder were then adjusted to achieve a reasonable correlation with the PCBC™ schedules.The enhanced Footprint Finder program was used to batch-process nearly 54 000 schedules using 20 elevations, 17 shutoff grades, four heights of draw, two different copper grades (modelled and upside), two layout refinements within the existing footprint and a variety of production ramp-up rates to 120 kt/d. The study team developed processes to analyse large amounts of data, to assist in selecting a matrix of the best schedules for detailed assessment using PCBC™. Three hundred PCBC™ schedules were developed.The detailed trade-offs between the scenarios is currently underway with promising results. This paper outlines the methodology used in evaluating the numerous alternatives.CITATION:Gantumur, J, Godard, R, Prince, F and Pascoe, C, 2016. Development and evaluation processes of cave production schedules for the Resolution copper project, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 59–64 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By A L. de Ambrosis, S J. Clarke

In the non-codified realm of tunnel design there are issues which are sure-fire instigators of controversy. This paper presents a discussion regarding one particular issue which in the authors’ experience often results in comment and debate. This issue only forms part of the rock load assessment process, but it is specifically addressed with the intention of presenting a rational basis for design, which may result in broader acceptance within the tunnel design community.The issue considered relates to the characterisation of in situ rock stresses for the design of tunnel support in the Sydney Basin. A summary is given of the literature on the topic, with emphasis on the main sources of uncertainty and contention. A design approach is proposed, with particular focus given to the numerical modelling of in situ ground stresses and the approach used to ensure that the adopted stress regime is consistent with the assumed ground model. The resulting variability in the initial stress field is discussed and comparisons made to the test database.CITATION:de Ambrosis, A L and Clarke, S J, 2014. Characterisation of in situ stresses for tunnel lining design in the Sydney?Basin, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 247–252 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By G J JAMESON

The flotation cell has undergone a number of changes since the process was first introduced in Broken Hill in the early years of this century. The development of the mechanical flotation cell is reviewed, followed by a discussion of more recent developments such as the flotation column, the air-sparged hydrocyclone, the Wemco-Leeds cell, the Bahr and Deister columns and the Jameson cell.

Jan 1, 1992

By A Krishnan, C Garcia, I Luna-Berbesi

The discovery and exploration of deposits are progressively shifting to extremely remote regions and greater depths. As a result, exploration costs and the economic risk of a bad investment increase. Current megatrends in the exploration and mining sector indicate a growing demand for the implementation of automation, digitalisation, and machine learning techniques. The implementation of a multi-sensor-based core logging device (DMT, 2024) was done on 400 m of drill cores to optimise interdisciplinary processes in terms of time and quality, by using interlinked and consistent data in real-time, to obtain reliable predictions that support and speed up decision-making. The results are consistent with the laboratory data previously obtained by the mining company, highlighting the benefits of introducing ANCORELOG into their core logging procedures.

Sep 1, 2024

IN the recent monograph on Broken Hill, N.S.W., by E. C. Andrews,* two independent petrological reports appear as Appendices 1 and n, by W. R. Browne and F. L. Stillwell respectively. In these considerable differences of opinion occur. Andrews contributes to some of the questions at issue, but no analytical review of the differences appears in the body of the report. Their development may invite question, and the following notes have been prepared partly in explanation and partly as a summary of some of the divergences. The soope of Browne's report extends over the whole district of Broken Hill, while Stillwell's deals with the rocks within 25 chains of the main lode. The more difficult and important rock-types occur in both areas, raising similar questions. In both cases observations extended beyond the limits of the prescribed areas. Broadly, Browne faces his problem as a study of a series of primary igneous rooks, acid and basio, whioh are intrusive into a series of sillimanite gneisses. The development of the sillimanite gneisses is regarded as belonging to an earlier period than the intrusion of the igneous rooks, while the gneissio structures of the latter are features which are incidental to their orystallization, and are not acquired subsequent to their consolidation. He finally produoes a picture in which his views of igneous injection and differentiation takes a prominent place. One direct result is the claim that three separate periods of metamorphism have oocurred in the Broken Hill area. Stillwell primarily examines the rooks as schists and gneisses since their present dominating features have been acquired during metamorphism. The effort is made to understand suoh differences as might arise from differing conditions of metamorphism upon rocks of similar and different oonstitution. The aim is to divest the rocks of those oharaoters which are due to metamorphism before approaching the questions of intrusive relatio'nships between igneous rocks andsediments.

Jan 1, 1924