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By M Logsdon, B Johnson, M Fordham

The underground Neves Corvo copper-tin mine in southern Portugal currently disposes of its tailings in a ætraditionalÆ wet tailings impoundment. With the development of new technologies for preparation and transport of thickened tailings or paste, alternative tailings disposal options have become available that provide a more sustainable water management system and a higher degree of environmental protection. In addition, growing European resistance towards subaqueous disposal may well result in mandatory use of dry disposal methods in the near future. Twenty-four tailings disposal alternatives were evaluated through a cost-effective and easily-implementable bench-scale geochemical screening program conducted at site. Since the tailings are pyrite-rich and highly acid generating, particular emphasis was placed on monitoring likely indicators of sulfide oxidation under the various simulated disposal scenarios. Dependent parameters investigated as part of the program included moisture content, use of alkaline additives (lime, cement), use of a bactericide, and agitation. Response parameters included paste pH, specific conductance, and temperature as indicators of oxidation. The testing was carried out for 30 weeks. Results indicate that a number of relationships between the geochemical stability of the samples (ie sulfide oxidation) and sample characteristics can be readily identified. Based on the results of the screening program, a limited number of tailings mixtures have been selected for further long-term testing in field weathering cells to aid in the identification of the optimal mix design for future tailings disposal at the Neves Corvo Mine. This type of testing provides an inexpensive and reliable methodology for semi-quantitative comparison between tailings disposal alternatives, in particular at locations where more rigorous evaluation through long-term, fully replicated testing is not immediately feasible.

Jan 1, 2003

Modelling and Optimisation of Direct Reduction of Iron Ore by Coal in a Rotary Kiln

Sep 13, 2010

By W J. Rankin, D R. Swinbourne

There are large tonnages of low-grade manganese ores in India fromwhich it is uneconomic to produce ferroalloys by conventionalsubmerged arc furnace smelting. A possible way to utilise these ores is to smelt them with carbon to produce pig iron and a manganese-rich slag, then to metallothermically reduce the molten slag to silicomanganese. Thermodynamic modelling of the metallothermic reduction stage using aluminium, silicon or aluminium-silicon alloy as the reductant at 1450¦C showed that an acceptable grade of silicomanganese could be produced. Manganese recoveries were predicted to be about 80 per cent. Heat balances indicated that silicothermic reduction may not produce enough heat to maintain reaction temperature. Small-scale laboratory experiments showed that the manganese grade of the alloys, and the manganese recoveries, were close to those predicted, but those for silicon were muchlower. Aluminothermic reduction produced the highest grade manganesealloy. The slag-metal equilibrium involving manganese, silicon and their oxides was investigated and it was found that equilibrium was not attained in any of the experiments, due probably to the very low rate of reactions involving silicon. This could be used to advantage in practice to achieve higher manganese levels in the alloys.

Jan 1, 1998

For the past 3 years Waihi as a community has been actively engaged in consultation about its future with regard to the environmental, cultural, economic and social viability. This has been made possible through the implementation of the Waihi Community Vision (WCV) process which bought together a diverse range of people and interests.   Through their collaboration and collective energies, they produced a montage of possibilities for the future of Waihi, known as the 2020 Vision. A proceeding evaluation process was adopted by the group to enable the myriad of projects to be assessed and prioritised in terms of the communityÆs social, economic, cultural, environmental and spiritual values.   From this came the desire to be involved in the implementation of these ideas and create an organisation that could facilitate the successful manifestation of the 2020 Vision and other suitable projects.   The Vision Waihi Trust (VWT) was formed in February 2006 and is intended to be a tool through which the community can address issues about its future sustainability. They will work collaboratively with community groups, Hauraki District Council and Newmont Waihi Gold to develop and implement innovative and practical solutions. It should be acknowledged that such outcomes are subject to influence by both external and internal factors and it is important to consider this when looking at sustainability issues.   Waihi is now at a very interesting stage of its development and has the opportunity to proactively design and implement plans to determine its future rather than just let things evolve. A town with a strong sense of its roots and with a strong community identity may be a more attractive as a place live and work. There are additional business opportunities which may also be stimulated by a community that takes charge of its own destiny.   The process that has been worked through over the past three years gives a solid foundation on which to build and must be viewed as positive community development. Waihi certainly has a unique proposition to take to the marketplace, based on its rich gold mining heritage and current modern day mining operations. This requires investigation, refinement and implementation and Vision Waihi Trust looks forward to building to a vibrant and prosperous Waihi in the years to come.

Jan 1, 2006

By G M. Volkmann

Pipe umbrella support systems – also called canopy tube systems – have been used successfully for tunnelling in challenging ground conditions since the 1970s. Historically, the drilling unit was the limiting factor for pipe umbrella installations – less attention has been paid to pipe couplings and their influence on labour time and load-bearing capacity.This contribution investigates the influence of the type of pipe connection on the load bearing characteristics of a connected pipe and discusses associated influences on design calculations and installation performance. Standard thread connections reduce the effective cross-section and thereby load-bearing capacity in the connection area. To achieve design parameters, over-dimensioning of the un-weakened pipe section is the only way to overcome this limitation. Recently, two new, alternative connection types were designed and developed for connected pipe umbrella pipes. The first one is the nipple coupling, consisting of fitting with a threaded connection that is pressed and welded into the ends of standard tubes. The second type is the squeezed connection, which mechanically connects non-threaded pipe ends, achieved by force-fitted squeezing from the drill rig. Both coupling types have technical as well as operational advantages compared to the common thread couplings, which are the weakest point in the support system.In the following sections significant technical differences are explained, design values given and a site example presented to illustrate the operational advantages of the newly developed coupling?type.CITATION:Volkmann, G M, 2014. Development of state-of-the-art connection types for pipe umbrella support systems, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 333–338 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By D Flint, O Rindriatmoko

PT FreeportÆs Deep Ore Zone (DOZ) Mine is the latest block cave mine within the East Ertsberg Skarn System (EESS).Issues with undercutting and stress concentrations at the extraction level were experienced, leading to reduced pillar strength.The extraction level-related issues became more pronounced, leading to local panel drift collapse, in an area that was over 100 per cent extraction. A review of ground conditions, panel collapse descriptions, and factors contributing to panel collapse are presented in this paper.

Jan 1, 2005

The ERMS Process was developed during four years of testwork by Austpac Gold NL to overcome the severe metallurgical problems of the ilmenite atWestport, in the South Island. These deposits have been known for about one hundred years. They were originally mined for gold, and only later attracted attention as a possible source of titanium minerals.   The resource is of world scale and may exceed 20 million tonnes of contained ilmenite. Similar deposits occur at Barrytown further south and together these areas would constitute an important opportunity for export-oriented mineral development, if a viable beneficiation technology were available. Further processing is essential, as the composition of the ilmenite is well below market specifications.

Jan 1, 1993

By G Brudek, P Elestedt

Schalker Eisenhütte und Maschinenfabrik GmbH, Nordic Minesteel Technologies and Bombardier Transportation have developed an evaluation tool that considers the main cost drivers of the rail, truck and conveyor haulage systems on the market today. In almost every circumstance, the advantages of a haulage solution are clear. A haulage system is outlined that is fully automated, including driverless operation, and that provides increased tonnage, safety and equipment life and reduced maintenance downtime. The haulage system has been implemented by a number of companies, including Codelco, LKAB and Freeport’s Grasberg mine. CITATION:Brudek, G, Elliott, R P and Elestedt, P, 2016. Moving mORE for less, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 535–542 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By D H. Lee, J F, J H. Rubinstein

This paper examines the problem of optimising the life-of-mine costs of an underground mine, focussing particularly on the costs associated with the underground development needed to provide access to and haulage from the ore zones. This mine optimisation problem is modelled as a network and a solution technique is outlined. The effectiveness of this solution technique is then demonstrated by applying it to a prototype test example and some actual case studies. Finally, extensions of this technique to other underground mining problems are discussed.

Jan 1, 2000

By S Jahanshahi, D R. Swinbourne

A knowledge of the value of the activity coefficient of cobalt oxide in slag as a function of composition and temperature is necessary if effective strategies are to be devised to maximise the recovery of cobalt in nonferrous smelting processes. This work reviews previous studies and shows that comparison and evaluation of the results is hampered by variations in the choice of standard states for the species. Published results have been recalculated to a common set of standard states with a preferred value for the Gibbs free energy of formation of cobalt oxide. It has been shown that the value of the activity coefficient of cobalt oxide referred to the solid standard state in iron silicate slags is approximately two, at temperatures from 1523 to 1623¦K. It is suggested that some contradictory results are most likely due to errors in the measured partial pressure of oxygen.

Jan 1, 1998

A search for the keyword nano reveals that it has not made a significant entry into the mineral processing research literature. In contrast, the terms micelle, colloid, interface, and monolayer are well established there. By considering nanoscience as colloid and interface science at the nanoscale, it is claimed that several previous and current investigations in the broad field of mineral processing fall under the umbrella of nanoscience. Several examples from hydrometallurgical processing systems (invisible gold and activated carbon in gold extraction; monolayers, reverse micelles, and microemulsions in solvent extraction; nanobiofilms and nanoparticles in biohydrometallurgy) are highlighted in support of this view.

Sep 13, 2010

By E Macmillan

For any processing plant there will be deleterious elements or minerals which affect production or quality, and a strategy to predict their occurrence and mitigate their impact is required. An early objective of the Olympic Dam geometallurgy program was prediction of the acid consumption and gelling behaviour of the ore, which affects leach recovery, throughput and circuit availability. The geometallurgical test program measured the response of a wide range of ore types, and then relationships between mineralogy, metallurgy and chemistry were developed. Thus the drivers of acid consumption and triggers for gelling events could be described in ways that were meaningful to plant operations.To enable optimisation of the mine planning and ore blending processes, the parameters driving metallurgical response must be translated to the block model. Data support is critical in populating a block model. Assay information is easily obtained, but mineralogical and metallurgical information is more expensive and time consuming to collect. Hence population of a block model with mineralogical and metallurgical values using a conventional geostatistical approach is not always possible.An alternative approach employed at Olympic Dam was the development of a suite of assay-to-mineral algorithms. These algorithms were calibrated using all available mineralogical information, and this enabled the calculation of mineral abundances for more than 1.5 million assayed samples. Estimation of the minerals in the block model, and the generation of acid consumption values for each block could subsequently occur.The use of back-calculated mineralogy from assays as part of process model generation is an innovative tool which can be used for mine planning and optimisation and to ensure the plant does not receive any unwelcome surprises. Ultimately, one purpose of geometallurgy is to predict potential processing issues and their drivers so that these can be mitigated. A strategy to achieve this is outlined hereafter.

Sep 5, 2011

By Secis R

Northparkes Mines is located 27 km northwest of Parkes in central west New South Wales. The E26 deposit is the largest of all defined to-date in the area, containing over 50 per cent of Northparkes' resources and reserves. The combination of orebody geometry and geotechnical characteristics provide ideal conditions for the block cave method of mining of the first lift of the E26 deposit. Although this method of underground mining has been used for decades in other countries, E26 is the first example of its use in Australia. Copper-gold mineralisation at Northparkes is related to quartz monzonite porphyries that have intruded coeval Ordovician volcanics. Sulphide mineralisation (dominantly bornite and chalcopyrite) occurs principally within quartz veins associated with the porphyry intrusions. Veining and mineralisation occurs within both the porphyries and volcanics. To optimise the recovery of a resource within a block cave mine, a good understanding of the rock mass and ore flow characteristics is essential. These have a significant effect on the fragmentation size and range and on parameters such as the drawzone spacing, height of interaction zone and dilution entry. As ore within a cave column moves and mixes when material is extracted from below and beside it, the total reserve extracted is unique for a particular draw strategy/production history. Until recently, reserve estimates and production schedules were based on the application of a uniform dilution factor to the tabulated resource. However, given the complicated flow and mixing within the cave column, such a simplistic approach can produce erroneous results. Northparkes Mines purchased and sponsored the upgrading of a commercially available software package specifically developed for modelling removal of resource blocks under caving conditions. This Gemcom software package, PC-BC, has been used for mine planning, reserve reporting and production scheduling. Blocks within it resource block model are converted into a mineable reserve taking into account mixing and dilution during depletion of drawcolumns (by horizontal and vertical redistribution of insitu tonnage and metal). As PC-BC gives individual drawpoint reserves, it can be used during the planning stage to determine whether or not a drawpoint is economic. For E26 Lift I an optimal layout containing 130 drawpoints has been developed based on a nominal 14 m x 14 m drawpoint spacing and a 0.8 per cent equivalent copper (eCu) cut-off grade. Annual production schedules for the depletion of material above this layout are based on: I higher tonnage removal from higher grade drawpoints in the early years of production; and 2 drawpoint production rates proportional to the total tonnage of orr remaining in the drawcolumn up to the optimal height of draw tier subsequent years. The reserve is tabulated from the combined annual production schedules over the life of the lift. The pre-mining reserve for Lift I of E26 is 26.6 Mt at 1.43 per cent copper and 0.39 g/t gold, of which approximately 23.4 Mt will be extracted under caving conditions. By scaling down the annual production schedule, weekly drawpoint tonnage calls can be given for short-tern production scheduling.

Jan 1, 1997

Prediction of fragmentation by blasting is most commonly based on theassumption that a single distribution of pre-existing discontinuities is present within a blasted rock volume and that the underlying mechanism of failure is tensile failure. It is assumed that the tensile stress field created by a blast initiates and extends radial cracks around the blastholes. Interaction between radial cracks from different blastholes and the free surface creates rock fragments. In reality, fragmentation of the rock occurs due to two mechanisms.One is related to the compressive-shear failure of the rock (mainly rock matrix) close to the blastholes, while the second mechanism is the previously mentioned tensile failure of the rock mass. The secondmechanism of failure occurs in the form of extension of the larger cracks in the region beyond the crushed rock, and this type of fragmentation occurs after the crushing phase. In the case of hard rock or blasting where the extent of crushing is minimal, the currently used prediction methods give a reasonably good result. However, there are many blasting conditions where the amount of rock crushing is significant. In the case where fragmentation of the given rock volume occurs dueto two different mechanisms, modeling of the rock fragmentation with a single distribution function is not appropriate. To model the fragment size distribution generated by two different mechanisms, it is necessary to use a two-component fragment size distribution function and a scaling parameter that will determine the proportion of the fragmented volume created by each mechanism. The purpose of this paper is to present results of blast fragmentation modeling based on two mechanisms of failure. The two-component model (TCM) utilises experimentally determined parameters from small scale blasting and parameters of the Kuz-Ram model, for more accurate prediction of the complete rock fragment size distribution curve. The methodology is such that it is possible to predict complete fragment size distribution, including fines, of ROM product for a future mine, at the feasibility phase of mine design.

Jan 1, 1999

The Earth Moving Equipment Safety Round Table (EMESRT) was established by mining companies in 2006 to influence manufacturer's equipment design through a process of engagement. 2010 EMESRT member companies include Anglo American, Barrick, BHP Billiton, Centennial Coal, Collahausi, Newcrest, Newmont, Rio Tinto, Vale and Xstrata.Driven by a persistent need for retrofits to new equipment, such as haul trucks, EMESRT initially engaged with Surface Equipment Manufacturers including Caterpillar, Komatsu, Leibherr, Hitachi, Le Tourneau and Terex. These OEMs responded positively to the EMESRT initiative, welcoming the opportunity for dialogue with an aligned industry regarding human factors issues related to equipment design, rather than needing to respond to the disparate range of demands for design modifications previously received from individual customers. This engagement process is about making global sustained changes within the OEM organisations and within the mining companies. It is a very international exercise. For example, over two weeks in September 2010, a total of 21 different miners from ten different companies travelled from Australia, South Africa, Canada, Brazil, Singapore and the United States to engage with OEM counterparts who assembled from the United States, Japan, France, Sweden, Finland and Germany. EMESRT Surface Group representatives completed a whirlwind tour of the major North American manufacturers of mining equipment. Starting in Dallas (Atlas Copco, LeTourneau), this tour passed through Gainesville (Sandvik), Newport News (Liebherr), Guelph - Ontario (Hitachi) and Milwaukee (P&H Mining/Joy Global; Bucyrus), before winding up in Peoria, Illinois (Komatsu, Caterpillar). Over nine meetings, this group engaged with 129 individuals from nine OEMs. The EMESRT group welcomed miners from four non-member companies to come along for the meetings. These companies are Syncrude Canada Ltd, the Kearl Oil Sands Project - Imperial Oil (ESSO), Suncor Energy Ltd and Teck Resources Ltd.Other mining industry sectors have now expanded the EMESRT scope from surface mining to include exploration and underground mining equipment. In 2009, EMESRT was organised into four Technical Groups, consisting of EMESRT member company representatives, to focus on engagement with OEMs of surface, underground coal and soft rock, underground hard rock, and exploration drilling equipment. An advisory group has been formed to coordinate activities between all workgroups and provide strategic direction and cohesion between all activities. The Minerals Industry Safety and Health Centre (UQ-SMI) facilitates and coordinates all EMESRT activities on behalf of member companies. Building on successes with individual Surface Mining OEMs, EMESRT now aims to help OEMs in their transition to a sustainable design process that will incorporate and address specific design philosophies at the concept phase of design, so that significant improvements can be made up front for little cost within the overall budget. EMESRT members plan to educate all stakeholders, internally, within their own companies, and externally, by addressing industry associations, regulators and other end users about new ways of evaluating equipment design based on EMESRT purchasing specifications. This presentation will outline the EMESRT approach and report on progress in 2010.

Dec 6, 2010

By J Li, J Regan, D Payne

The Caval Ridge Mine is an open cut coalmine and located within the Bowen Basin region in Central Queensland, and commenced mining and processing operations in 2014. A number of geotechnical challenges for managing dragline bench and lowwall stabilities have been encountered in both southern and northern pits over the years. Southern Pits contain steep seam dips of up to 15° (27 per cent) whilst the northern pits also have shears below pit floors. Geotechnical guidelines to manage the risk of dragline bench failure and lowwall instability have been developed and improved since these geotechnical challenges were identified. The dragline guidelines include dragline tub offset distances from the 60° Line (SDL) or buttressing thickness for different seam dips greater than or equal to 8°. The low wall stabilisation guideline established floor disruption widths and depths depending on seam dips and presence of floor shears to known depths of up to 3 m. As mining operations advance, lowwalls have remained stable until floor disruptions were fired, then returned to stable soon after the shot. The maximum distance of lowwall cracking with blasting has been as far back as the second spoil peak (the prestrip truck dumps construction limit). These failures need to be eliminated to allow the operational flexibility and haulage benefit of constructing the prestrip truck dumps behind the first spoil peak, while maintaining no risk to personnel or equipment. The floor shear depth was verified by collaborating with the exploration teams and taking advantage of the already planned 8-inch coal quality core holes, drilling them an extra 5–10 m past the coal seam floor and locating the shear presence. With this continuous improvement effort, no lowwall failures have occurred during floor disruption firing from the second strip after the new floor disruption depth guidance have been applied. This paper documents the processes for developing these geotechnical guidelines, operational implementation, and outcomes. Operational applications over the years confirmed that these guidelines have effectively managed the dragline bench and lowwall failure risks related with the steep seam dips and floor shears in this open cut coalmine.

Nov 29, 2022

By M Fitzgerald

Fimiston Open Pit is operated by Kalgoorlie Consolidated Gold Mines (KCGM) as a joint venture between Barrick Gold and Newmont Mining. Over 110 years of underground mining resulted in the development of nearly 3500 km of underground workings including backfilled and open stopes up to half a million tonnes in size. These voids significantly complicate blasting processes at KCGM, influencing blast movement direction and magnitude. Blast movement monitoring to improve mine reconciliations was identified as an improvement project in the business plan for the geology team in 2008. Following successful trials in 2008 to 2009, blast monitoring and translation of ore blocks were implemented as a permanent grade control program from late 2009 and is now part of the Management Operating System (MOS) of the mine. This paper presents a summary of results from the Blast Movement Monitoring (BMM®) data collected to date. Ore blocks at KCGM are translated primarily using BMM® data. This data is obtained from the BMM® system which measures the movement of a radio transmitter installed in a blast pattern from a preblast position to a post-blast position. The application of the data collected by the BMM® tends to be both mine site and blast specific. At KCGM, an average distance obtained from the BMM® data within a given shot is the primary method used for translation. In the case that BMM® data is unavailable, a theoretical movement vector established from Orica Shotplus with distances gained from the historical BMM® database is used. Data is presented in an ore loss and dilution exercise for a bench undertaken at KCGM to understand the potential effects on reconciliations. Improvements that have flowed from implementing blast monitoring include improved reconciliations when combined with other grade control improvement projects. The increase in liaison between the geology and blast personnel at KCGM has been a significant improvement gained from the implementation of the blast monitoring program. This has allowed a better understanding of blast movement and the effects on ore dilution and ore loss by the mine geology team. In addition, the discussion of blasting tie-in plans between geology and blasting personnel has been improved which leads to more favourable blasting practices that take ore movement into account.

Aug 22, 2011

By M Uceda, E Guerra, Y Choi, J L. Shepherd

In this paper we describe the leaching characteristics of pure gold in thiosulfate solutions that contain a known chelator; meso-2,3-dimercaptosuccinic acid (DMSA). The interfacial and chemical characterisation of the system was accomplished using both electrochemical methods and inductively coupled plasma mass spectrometry (ICP-MS) analysis after pure gold samples were exposed to solutions composed of 65 mM Na2S2O3, 1 mM NaOH and a range of DMSA concentrations. In the absence of DMSA, cyclic voltammetry revealed the onset of thiosulfate mediated gold dissolution, the degree of which was reduced at more positive potentials due to the formation of oxidised thiosulfate products on the gold surface. The addition of small amounts of DMSA (<10 ¦M) to the electrolyte resulted in minor changes to the voltammograms indicating a subtle interaction of the additive with the gold surface that may improve leaching. However, at higher concentrations of DMSA (up to 100 ¦M), electrochemical evidence suggests the formation of new oxidation products in solution as well as the formation of more compact monolayers of DMSA on the surface, which contribute to partial repassivation of the surface. The influence of DMSA on thiosulfate leaching of pure gold electrodes at the open circuit potential for a period of 90 minutes was tested and the corresponding gold leaching performance evaluated with ICP-MS analysis. Our data shows that small amounts of DMSA (1 ¦M) doubled the amount of total gold in solution when compared to the same study in the absence of the additive. However, higher concentrations (5 ¦M DMSA) reduced the overall amount of dissolved gold. These results may point to a mechanism where small amounts of DMSA improve leaching by adsorbing onto the surface in a highly defective monolayer that partially blocks or disrupts the formation of passivation products caused by thiosulfate oxidation, but excess DMSA can limit the leaching process itself by forming too coherent a monolayer on the gold surface.CITATION:Uceda, M, Choi, Y, Shepherd, J L and Guerra, E, 2013. Investigating the influence of meso-2,3-dimercaptosuccinic acid on thiosulfate leaching of bulk gold electrodes, in Proceedings World Gold 2013 , pp 207-214 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

Improved roof control in high deformation tailgate environments has been achieved over the last decade through development of stiffer and increased capacity standing support products. æThe CanÆ is one such development, being a steel cylinder containing a weak cementitious fill, designed to essentially fold in upon itself whilst maintaining strength. A laboratory study to better define the relative load contributions of the steel cylinder and fill, the confining interaction between these components and most importantly, the potential impact of varying the steel and/or fill properties is described. This would enable the support engineer to ædial-upÆ the desired strength and stiffness properties and optimise the standing support design with respect to load capacity, stiffness, weight (handling) and cost. Design curves to optimise strength based on steel casing thickness, fill strength (confined and unconfined) and æCanÆ geometry were established. Scaled-down (one-third) samples were used in the test program and found to adequately reflect the loading behaviour of full-scale versions, thereby providing significantly greater scope for further product development at less expense compared with testing full-scale products.

Jan 1, 2005

By J D. Pease, J M. I Tuppurainen, P D. Munro

This paper examines how legislation and regulation can be external drivers of technical change in mineral processing and extractive metallurgy and how the industry can respond. Two examples are considered; the production of copper metal from concentrates and the cyanide process for gold production.The Clean Air Act (1970) in the USA initiated a wave of attempted innovations in the extractive metallurgy of processing copper sulfide concentrates to meet forthcoming standards on sulfur dioxide emissions. Interestingly, a satisfactory technical solution existed (flash smelting and gas capture) but had not been widely adopted.Nearly fifty years later the primary copper industry finds itself with new challenges. One major challenge is how to deal with the increasing level of arsenic in copper concentrates. Most countries impose an upper limit on arsenic in imported concentrate; typically, 0.5% As or less. Higher arsenic concentrates can be blended with cleaner ones to meet the limit, but this tactic cannot be used indefinitely as the average arsenic level of global concentrates rises inexorably. Further, smelters (often in urban locations) cannot be expected to deal with both ever-increasing arsenic in the feed and stricter restrictions on emissions and disposal. A rising “inventory” of primary copper deposits are already constrained from development by high arsenic concentrate. These deposits will need to be developed if future copper demand is to be met. An economic and technical solution to arsenic is needed. The gold industry may also face challenges in the use of cyanide, by far the dominant lixiviant used in gold and silver production. Public perception has driven restrictions on the use or transport of cyanide in some jurisdictions. History suggests that such pressure is only likely to increase. While there are several alternative lixiviants, none can yet match the utility and economics of cyanide.Such important issues will not be resolved by incremental change or new equipment items. They require development of new process technology - a tectonic event rather than an incremental change. It requires sustained effort (and expenditure) over decades and is very unlikely to result from “business as usual” for producers, suppliers or academics. Past major process developments were driven by a dire need for economic survival or by legislative change. What will drive the future changes?CITATION:Munro, P D, Pease, J D and Tuppurainen, J M I, 2017. Technology change by regulation – a cresting wave?, in Proceedings MetPlant 2017, pp 45–58 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017