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By J Hadjigeorgiou, T R. Stacey

A ground support system is a combination of individual reinforcement and surface support elements that work together to retain and contain the rock mass. The various elements are subjected to external loads and to interactive loading between individual ground support system components. This paper focuses on the challenges in determining the capacity and behaviour of mesh, recognizing that installed mesh can be subjected to several loading mechanisms. Field observations from underground hard rock mines demonstrate that there are multiple types of damage and modes of failure of mesh. However, these are difficult to reproduce in a laboratory environment. A critical review has shown that existing mesh laboratory testing rigs reproduce very limited loading conditions that may not be representative of underground conditions. This has significant implications in quantifying and extrapolating the performance of mesh to ground conditions. CITATION:Hadjigeorgiou, J and Stacey, T R, 2018. Challenges in determining the capacity of mesh, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 280–290 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By B L. Sainsbury, M F. Lee, A Penney

For most practical rock engineering purposes, stress versus strength conditions around underground openings for which rock masses fail and their various modes of failure, are reasonably well-understood and predictable. Some rock masses and particular rock types fail slowly and relatively quietly. However, others can fail rapidly, violently and maybe with the ejection of significant broken rock. In some countries and in some mines, the latter style of violent fracturing and failure of the rock mass is referred to as ‘strain bursting’. It can be alarming and extremely hazardous to nearby miners and machines. For such situations, the design and installation of appropriate ground support, to provide a safe work place, can be challenging. At any particular mine site, it’s often generally understood which local rock masses (rock types) are prone to strain bursting. Competent and strong siliceous rocks and some massive sulphides are often the main offenders. While some neighbouring, equally-competent and strong rocks might also fail, they do so more quietly and without ejection. To understand this contrast, a better understanding of the fracturing process is required other than simple and standard strength versus stress considerations. Suites of standard intact rock properties from numerous Australian mines have been used to define and help understand different high-stress failure styles for component intact rock; especially those prone to violent fracturing (strain bursting). Simple considerations of micro-fracturing (defects in the intact material), plus the available energy at failure versus the energy consumed during fracturing, distinguishes between over-stressed and competent rock types that fracture violently and those that don’t. CITATION:Lee, M F, Penney, A and Sainsbury, B L, 2018. Proneness of competent over-stressed intact rock to violent fracturing, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 170–184 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By A Turner, P Hills, D Johnson

Underground mining for gold began in Beaconsfield in 1877 and development of the Tasmania Mine saw the sinking of multiple shafts, including the Hart Shaft over the ensuing 35 years. The mine closed in 1914 at a depth of 455 m due to prevailing economics, eventually reopening in 1999. The modern mine closed in 2012 after extending the mine from a historical depth of 455 m to the exhaustion of the modern Ore Reserve at a depth of 1210 m. West Tamar Council took over the lease for the immediate area around the Hart Shaft as an extension of the adjacent museum. The Hart Shaft and above ground structures became a significant drawcard for visitors. Tasmania was affected by sustained wet weather during May, June and July of 2016 which caused severe flooding and significant Statewide damage. This uncharacteristically intense wet weather caused saturation of the ground surrounding the Hart Shaft. Eventual shaft failure was first identified in August 2016. The failure of the shaft occurred at approximately 50 m below surface and resulted in a plug of material completely blocking the shaft. Significant surface subsidence affecting the surface infrastructure ensued. Due to the unstable nature of the surrounding material, it was determined that addressing the failure above the blockage would not provide a permanent solution to prevent the continued flow of material into the shaft. Many options to stabilise the shaft were considered, however it was assessed that a concrete plug in the shaft in competent ground at a depth of 100 m below surface and well below the blockage, would provide the only long-term solution. Man-entry was considered unsafe. The solution to access ultimately entailed filling the entire shaft with granular fill up to 100 m depth to act as formwork for a concrete plug. The rising mains at 400 mm and 250 mm diameter, which remained in place in the shaft, provided the avenue for placing the fill and ultimately, the concrete plug. Once the plug was in place the remainder of the shaft up to the underside of the blockage and over the top of the blockage to the surface was successfully filled with a combination of more granular fill and flowable cement stabilised sand. The Hart Shaft and surrounding above ground infrastructure was successfully stabilised and re-opened to tourist access. CITATION:Johnson, D, Turner, A and Hills, P, 2018. Stabilising and filling the Beaconsfield Hart Shaft, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 42–57 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By A Vakili, F Harvey, H Greaves

Mine seismicity is one of the most difficult geotechnical risks to manage in seismically active mines. There are currently some established empirical and statistical methods that provide quantitative measures for seismic hazard assessment in operating mines. However, these methods are mostly suitable for quantifying the current or historical seismic hazard and often cannot be directly used to forecast the future hazards. Numerical modelling is the only analytical tool that can capture the level of complexities required for a meaningful analysis of mine seismicity and therefore to facilitate a reliable forecast of future hazards. However, there is currently no widely accepted and established guideline and methodology for analysing and forecasting mine seismicity using numerical modelling. This paper first provides a background on previous published studies on this subject and then outlines the key aspects that can affect the reliability of the forecasting for mine seismicity. These aspects include a) processing of historical seismic data, b) selection of suitable numerical modelling approach, c) Post-processing and interpretation of the model outputs. A case study is then presented for the Gwalia Deeps Mine where a new framework was developed to forecast future mine seismicity. High-quality seismic data for a period of five years was used for back-analysis and comparisons with the numerical modelling outputs. After development of the method, the future seismicity was forecast for the next 12 months and the actual seismicity was monitored against the forecast during this period. Results of this study shows promising potential for the proposed framework to be applied more routinely and at other mine sites. However, more validations are required at Gwalia Deeps mine as the mine proceeds to deeper levels. In addition, the method needs more improvements and should be tested and validated at other mining operations before it can be established as a proven method. CITATION:Vakili, A, Harvey, F and Greaves, H, 2018. Forecasting mine seismicity – towards a more established methodology, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 207–222 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By X Feng, X Zhang, W Sun, Y Zhe, K Hou, B Zhao, H Liu

Pulang Copper Mine, being China's largest newly built mine using block caving, boasts an annual production capacity of 12.5 million tons. Production level and roadway stability hold the key to the successful application of block caving. However, with Tong Kuangyu being the only mine in China which has applied such a method, we currently lack relevant experience in the successful application of the method. This paper has studied the influence of different rock mass zonings, fault thickness, fault dip angles, on-site construction quality on the production level, roadway stability of block caving through numerical simulation and analysed the roadway stability in different kinds of support solutions so as to ensure the successful application of block caving in Pulang Copper Mine. The results have shown that the existing support method in Pulang Copper Mine can meet the requirement of roadway support in zone II and III, but could not satisfy the demand in terms of support strength in the relatively fragmented zone I area. When roadway passes through the fault, the deformation of surrounding rock and plastic zone of roadway will gradually decrease with the increase of fault dip angle; the deformation of surrounding rock and plastic zone of roadway will gradually increase with the increase of fault thickness. An ideal support effect can be achieved through the joint support of grouting and bolting when roadway passes through the fault. In the measured model of on-site construction, there is stress concentration in the intersection between the access and transverse drift of ore removal. Therefore, the stability of the roadway can be improved by improving the construction quality. CITATION:Sun, W, Hou, K, Zhang, X, Feng, X, Liu, H, Zhe, Y and Zhao, B, 2018. Research on supporting technology for production level roadways of block caving in Pulang Copper Mine, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 95–106 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By M Robotham

In April 2013, Rio Tinto Kennecott Copper’s (RTKC) Bingham Canyon mine experienced what is arguably the world’s largest ever in-pit slope failure. The failure initiated along a major, continuous, low-strength bedding fault, named the Manefay bed, and comprised approximately 145Mtonnes of rock and waste dump material. Initial East wall slope deformations were detected some months prior to catastrophic slope collapse by RTKC’s slope monitoring systems. However, the failure mechanism was different to that which had historically been experienced in the prior more-than-100 years of open pit mining. Failure occurred as two separate events, the initial one likely consisting of a frictional failure of rock materials along the Manefay bed itself, before a second phase of failure occurred, which included a large mass of old rail dump material. The combination of these events led to a much larger failure run-out than had been anticipated by the RTKC team which led to loss of, and damage to, mining equipment and infrastructure as well as significant interruption to mining activities. Due to the diligent monitoring of the slopes no safety impacts were experienced at the mine, and as such the details and learnings from this failure can readily be shared with the broader mining and geotechnical industries to avoid similar recurrences elsewhere. This is an extended abstract only. CITATION:Robotham, M, 2018. Bingham Canyon Mine – from adversity to excellence, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 3–4 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By Giuseppe Pintaude, Carlos Mauricio Lepienski

The evaluation of the tribological behavior of thermochemically treated surfaces, such as carburising and nitriding, is of uppermost importance for the productive chain of tools, molds and matrices. However, the use of tribological tests for these surfaces should be well selected to avoid erroneous evaluations, in particular considering the effect of the substrate at different levels. In this context, the linear scratch test may be well suited to distinguish the roles of the surface and the substrate. For that purpose, this paper presents a review on the use of this type of test for tribological evaluation in terms of the performance of thermochemically treated surfaces. The approach used is multiscale, considering what types of results are obtained from each load range used and the applications for each one of them.

Nov 22, 2018

By K Tungpalan, E Wightman, M Edraki, E Manlapig, L Keeney

The depletion of easily mined high-grade ore bodies resulted in the industry having to exploit lower grade, complex resources (Albanese and McGagh, 2011; Darling, 2011; Randolph, 2011). The trend is now towards mining and processing of low-grade and complex ores (Darling, 2011; Yingling, 1990). Variable geological and mineralogical characteristics, and complex mineralogy and texture can result in large variations in metallurgical response and also cause challenges in processing. (Carson, 1995; Lorenzen and Barnard, 2011; Yingling, 1990). Variability and the complex nature of ores are fundamental sources of risk that often cause the greatest economic impact (Dusci et al., 2007; Williams and Richardson, 2004). Hence it is important to effectively characterise these types of ore bodies and assess their processing performance (ie recovery, grade). To enable this, there is a need for the following: (i) characterisation of geological, mineralogical and metallurgical variability in the ore body; (ii) effective selection of drill core with characteristics that represent the range of ores in the entire ore body. CITATION: Tungpalan, K, Manlapig, E, Keeney, L, Wightman, E and Edraki, M, 2018. A systematic approach of sample selection to predict processing performance of an ore body, in Proceedings Complex Orebodies Conference 2018, pp 67–70 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By F Shi, G Ballantyne, K Runge

There has been minimal innovation in the methods used to process an ore over the last 50 years. Productivity increases have largely resulted in increased equipment size without implementation of parallel improvements in technology. Complex orebodies of the future will need mining operations to adopt new technologies and techniques to make future ore treatment economically viable. Three emerging technologies, namely high voltage pulse (HVP) pretreatment, fine screening and the HydroFloat<sub>TM</sub> coarse particle flotation cell will be presented in this paper and the potential benefits that may result if they are adopted in mineral processing circuits will be outlined. The barriers that must be overcome before they can be adopted by industry with confidence will also be discussed. CITATION: Runge, K, Shi, F and Ballantyne, G, 2018. New technologies that will potentially enable processing of complex orebodies, in Proceedings Complex Orebodies Conference 2018, pp 126–129 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By M Noakes

EcoTechnology refers to a series of potential metallurgical processes for complex ores, concentrates, tailings and slags that are all based on an initial chlorination step at low to moderate temperatures probably in a fluid bed chlorinator (FBC). Examples of the research and development (R&D) results are provided in this paper for a high grade Au/Sb Leach Tailings (EcoGold<sub>®</sub> Process), a very refractory sulphide Au concentrate, a refractory gold calcine tailings, a Cu/Au tailings (EcoCopper<sub>®</sub> Process), bulk polymetallic sulphide concentrates and polymetallic sulphide/oxide complex ores (EcoZinc<sub>®</sub> Process and EcoLead<sub>®</sub> Process). R&D on over thirty different ore types has been conducted at a bench scale as discussed. Latterly a dedicated pilot plant was designed and constructed by EcoTech Mining Pty Ltd (EML) and several of the different feed stock results have been confirmed by pilot plant testing. It is planned to scale up to a commercial demonstration plant. To demonstrate the versatility of EcoTechnology, bench and pilot plant test results on five of the projects are used as case studies as follows: Fosterville ‘leach tailing’, VIC; Wiluna flotation concentrate – BIOX Feed, WA; Wiluna calcine facility tailings, WA; Mt Morgan Cu/Au tailings, QLD; Polymetallic sulphide concentrates from Pegmont Deposit, QLD and Polymetallic sulphide/oxide ores from Commonwealth Mine Project, NSW. CITATION: Noakes, M, 2018. Improved recoveries and environmental outcomes from complex ores utilising EcoTechnology, in Proceedings Complex Orebodies Conference 2018, pp 122–123 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By R Valenta, A Littleboy

Geological heterogeneity is one dimension of complexity in mining. Significant effort is put into developing an understanding of this complexity so it can be used in resource estimation, mine planning and economic modelling. However, over the decadal lifespan of a mining venture, many other dimensions add to the complexity of a mining operation. These include: technological evolution, market fluctuations; investor confidence; social norms; local expectations; and ecosystem functionality. As with geology, these factors are all heterogeneous, uncertain, time varying and represented through sparse and incomplete datasets. Recent work (Valenta et al) is beginning to show us how these risks correlate in different global settings. By analysing data relating to known, but as yet undeveloped copper deposits, this work (the complex ore body database) is demonstrating that it is the combination of issues (both price sensitive and non price-sensitive) that determine the viability of a deposit for extraction in the 21st century.CITATION: Littleboy, A, Plint, N and Valenta, R, 2018. Mining as a complex system: do we need a new model?, in Proceedings Complex Orebodies Conference 2018, pp 41–43 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By T Craske, J Sykes, T C. McCuaig, M Jessell, A Trench

The prevalent strategic approach in the mining industry is one of planning. However, it is widely recognised that planning does not work in complex and uncertain situations (Mintzberg, 1994), such as those associated with ‘above ground’ non-technical orebody complexity (Trench, Packey and Sykes, 2014). Mintzberg, Ahlstrand and Lampel (2009) suggest the focus instead should be on strategic ‘thinking and doing’ and using the many ways to think about strategy to make sense of complex, uncertain, and unique situations. They therefore place great value in cognitive flexibility. Scenarios development utilizes several different thinking styles and thus assists with this type of flexible strategic thinking (Figure 1). The ‘Centre for Exploration Targeting (CET) Scenarios’ were developed with the ‘Oxford Scenario Planning Approach’ (OSPA) (Ramírez and Wilkinson, 2016). The OSPA aims more to improve the thinking skills of decision makers, rather than forecasting per se (Wack, 1985a, 1985b). As such, this paper focuses less on the content of the scenarios and instead on the practical value of scenarios in strategizing. CITATION: Sykes, J, Trench, A, McCuaig, T C, Jessell, M and Craske, T, 2018. Strategic thinking about long-term ‘above ground’ orebody complexity using scenarios, in Proceedings Complex Orebodies Conference 2018, pp 60–64 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By P Stewart, S Cowie, A Offer, J Carpenter, E Jones

The Ban Houayxai Gold-Silver Operation is a producing asset for Australian-based copper and gold producer, PanAust Limited. The Operation lies within PanAust’s 2600 square-kilometre Phu Bia Contract Area in northern Laos. Commencing production in 2012, Ban Houayxai is operated by PanAust’s Lao-registered company, Phu Bia Mining. PanAust owns a 90 per cent interest in Phu Bia Mining. The Government of Laos owns the remaining 10 per cent. The Operation mines an intermediate sulphidation epithermal gold-silver deposit and comprises an open-pit feeding ore to a conventional carbon-in-leach process plant. Metallurgical recoveries for gold and silver are approximately 75-85 per cent and 55 per cent respectively. To year-end 2017, the Operation had poured 0.65 million ounces (oz) of gold and 4.7 million oz of silver. The Ban Houayxai Ore Reserve supports a mine life of approximately four years from the end of 2017. The Ban Houayxai deposit is in an early Permian volcano-sedimentary unit which is part of a late Carboniferous to early Permian (310–270 million years ago) volcanic-plutonic sequence of the Truong Son Fold Belt. The deposit formed when hot saline (240–415°C, 2.7–13.0 weight per cent NaCl equivalent) fluids ascended from a geologically fertile island arc porphyry into overlying volcanics along a fault or faults in the early Permian (290–256 million years ago) (Manaka et al, 2014). CITATION: Carpenter, J, Cowie, S, Stewart, P, Jones E, and Offer, A, 2018. Machine learning at a gold-silver mine: a case study from the Ban Houayxai Gold-Silver Operation, in Proceedings Complex Orebodies Conference 2018, pp 82–85 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By A Tsoy

This abstract describes long-term mining schedule optimisation approach that may be suitable for complex marginal projects and is based on modern scheduling techniques. CITATION: Tsoy, A, 2018. Strategic mine schedule optimisation, in Proceedings Complex Orebodies Conference 2018, pp 91–92 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By P Gilroy

In recent technical investigations that were triggered from ore for rail shortfalls at Yandi, BHP Iron ore has identified a gap in resource knowledge relating to geo-metallurgical characteristics that predict materials handling performance and throughput. Within these investigations BHP has learnt that this lack of resource knowledge has translated to a lack of predictability associated with mine planning inputs which has resulted in poor compliance to plan and deviation management practices. A business value chain was developed in an attempt to identify the best possible solution to unlock this resource knowledge in the short, medium and long term planning horizons. A fast fail approach was taken with the implementation of hyperspectral blasthole analysis, which was chosen to deliver the best possible value driver for the asset. This report will detail the Yandi journey in expanding the hyperspectral and geo-metallurgical value chain, unlocking resource knowledge along the way. CITATION: Gilroy, P, 2018. Development of an empirical geo-metallurgical model that unlocks value of the mineral resources at Yandi Mine, in Proceedings Complex Orebodies Conference 2018, pp 85–87 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By M J. Davies, R S. Davies

Despite increased expenditure, the global discovery rate of world-class ore deposits has been in decline for over a decade (Schodde, 2017). Mineral exploration has traditionally followed an empirical approach, searching for evidence of mineralisation upon the surface of the planet, then drilling to define the extent of an ore body beneath the surface. As outcropping deposits in well-defined areas are depleted, there is a need for exploration to extend to less well-explored search spaces. One popular new frontier is exploration at greater depths beneath the Earth's surface. However, exploring for deep deposits with limited surficial evidence requires the implementation of predictive targeting methodologies (Hronsky, 2011; McCuaig & Hronsky, 2014). The Mineral Systems Concept (Hronsky & Groves, 2008; McCuaig et al., 2010) provides a framework for predictive exploration targeting. Ore deposit formation is recognised to be a focused mineralising event. These events represent self-organising critical systems and are underpinned by the interaction of complex, non-linear processes. Through the collection and analysis of datasets that map mineralising processes, it may be possible to predict the size and location of resultant ore bodies. CITATION: Davies, M J and Davies, R S, 2018. Beyond below-ground geological complexity: Developing adaptive expertise in exploration decision-making, in Proceedings Complex Orebodies Conference 2018, pp 95–98 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By G Corder

The aim of the circular economy is to accelerate the transition from a conventional linear take-make-dispose economic model to a circular model. It is restorative and regenerative by design and aims to keep products, components and materials at their highest utility and value at all times. This extended abstract presents a brief overview of the circular economy, provides application of the circular economy in other industrial sectors including the downstream metals value chain and proposes how circular economy thinking could progress the development of complex orebodies.CITATION: Corder, G, 2018. Can the concept of the circular economy help unlock complex orebodies?, in Proceedings Complex Orebodies Conference 2018, pp 8–10 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By R Morrison, P Walters, B Adair, V Jokovic

‘Grade Engineering<sub>®</sub> is an integrated approach to coarse rejection that matches a suite of separation technologies to ore specific characteristics and compares the net value of rejecting low value components in current feed streams to existing mine plans as part of a system-view’ (Walters, 2017). Two of these technologies are directly recoverable through screening stages: Natural Deportment and Induced Deportment. The potential for taking advantage of “Natural Deportment” by size following blasting and crushing has been demonstrated for a range of ore types. Simple and low cost screening can in some cases generate a fine product with improved grade and a lower grade oversize which can be directed to leach or to waste. Where an ore body consists of many different ore types, the traditional approach of blending to metal grade will often add to complexity of treatment, which will reduce the effect of “natural deportment” by size.CITATION: Jokovic, V, Walters, P, Adair, B and Morrison, R, 2018. Applying enhanced grade engineering to complex ore bodies, in Proceedings Complex Orebodies Conference 2018, pp 21–23 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By D. A. Hayman, N. Rambuda, N. A. Sithole, C. Hockaday, J. D. Steenkamp

"Mogale Alloys operates two alternating current (AC) submerged arc furnaces (SAFs), and two direct current (DC) open bath furnaces. These furnaces are capable of producing two products, silicomanganese (SiMn) and ferrochrome (FeCr), with a total production capacity of 110 000 t/a. This paper focuses on the silicomanganese process specific to Mogale Alloys, with a two-furnace operation facility that produces 55 000 t of SiMn per annum.IntroductionMogale Alloys is situated in Krugersdorp in the West Rand District Municipality in South Africa’s Gauteng Province. The Krugersdorp facilities were initiated by Palmiet Chrome Corporation in February 1963 to produce charge chrome (Basson, Curr, and Gericke, 2007). Mogale Alloys bought the Palmiet Chrome facilities in 2005 from Samancor Chrome. The Afarak Group currently owns 90% of Mogale Alloys.SiMn is produced in two 20 MVA submerged arc furnaces (SAFs), which were originally built for chromite processing, and ferrochromium (FeCr) in two DC open bath furnaces rated at 40 MVA and 10 MVA. When this paper was compiled, the 10 MVA furnace was not operational due to the high cost of production, and one of the 20 MVA SAFs was recently converted to produce FeCr due to market constraints. Mogale Alloys has 290 permanent employees with four contracting companies on site. The paper presented here focuses on the production of SiMn at Mogale Alloys.The high-level process flow at Mogale Alloys is summarized in Figure 1, which details the raw material input and the products produced by the two 20 MVA furnaces. SiMn is produced by carbothermic reduction of manganese-bearing raw materials from four different sources, namely Wessels, Mamatwan, and UMK ores, and BHP sinter feed. The carbon sources are bituminous coal from Forzando and Msobo, local suppliers in Mpumalanga."

Nov 1, 2018

By J. P. T. Kapusta

"The copper smelting industry faces increasingly stringent environmental regulations and must continue driving innovation to reduce energy usage in its production chain. With the coming of age of ‘bottom-blowing’ copper technologies in China over the last decade, much renewed attention has been brought to tuyere bath smelting for clean copper-making. Since bottom-blowing sonic injection was originally developed and implemented in steelmaking in the 1970s and lead smelting in the 1990s, the time seems appropriate to revisit the sonic injection concepts and dispel some myths. After reviewing the trends in the copper industry and providing a brief historical context of research and development related to sonic injection, the author presents a comparison of the main submerged tuyere bath smelting technologies, namely the Noranda Reactor (NR), the Teniente Converter (TC), and the Chinese Bottom-Blowing Smelting Furnace (SKS/BBS) for copper, and the Queneau-Schuhmann-Lurgi Reactor (QSL) for lead. The core of this article, however, consists of a brief description of the fundamental theories for sonic injection (jetting regime) and ‘sonic flow mapping’ to illustrate the relationship between the minimum tuyere back-pressure required to achieve sonic flow and the tuyere internal diameter. The article also offers a comparison between side- and bottom-blowing in jetting regime before concluding with the author’s vision of the new trend in submerged tuyere bath smelting. IntroductionIn the last decade, developments in the copper smelting industry have been driven by two key concepts: (1) increasing cleaner smelting capacity to meet the world’s growing copper demand, as illustrated in Figure 1, and (2) increasing process off-gas capture to comply with more stringent environmental regulations and abide by a corporate social responsibility ethic of a clean work environment (for smelter employees) and clean air (for families living around smelters). The copper smelting industry has also faced some major challenges in the last few decades, including (1) low treatment and refining charges (TC/RC or processing fees) impacting custom smelters, (2) lower concentrate quality and grades with higher levels of impurities (e.g. As and Hg), (3) higher processing and transportation costs due to the rising cost of energy, (4) restrictions in process intensification (tonnage oxygen usage) due to furnace integrity limits, and (5) scarcity of educated and trained personnel due to fewer metallurgists graduating from pyrometallurgical school programmes combined with a high retirement rate of skilled workers."

Nov 1, 2018