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By Alichurch P. D

Perseverance nickel deposit is located at latitude 27¦ 491S, longitude 1200 42'E, 330 km north of Kalgoorlie, Western Australia. Gossanous outcrops were discovered in April, 1971, and after further detailed surface investigations, percussion drilling led to diamond drilling by June, 1971. Up to December, 1972, 127 diamond holes totalling 45,590 m were drilled to indicate 33 million tonnes averaging 2.2% Ni using a 1% cut-off grade. The deposit occurs in a lenticular ultra- mafic unit emplaced in metasediments locally forming the eastern flank of the Archaean green- stone belt trending NNW from Leonora to Wiluna. To the east a major strike fault separates the metasediments from gneiss; westwards there is a sequence of metavolcanics with further ultra- mafic units. Length of the lens is 3500 m and it attains a maximum width of 800 In. The eastern contact is moderately regular, but the western contact is prominently embayed. Local strikes are NNW, and dips are steeply W. A set of strike faults cuts the ultramafics and enveloping quartzites. These are normal faults, parallel to the major eastern fault, dipping 65-70¦W. They impart a serrated pat- tern to the sub-outcrop of the western contact. Massive serpentinite is the dominant rock in

Jan 1, 1973

By B Davis, A H. Benzer, A N. Mainza, C M. Evertsson, L M. Tavares, M M. Hilden, M S. Powell, C Rule, G Asbj÷rnsson

The Mogalakwena North Concentrator of Anglo Platinum Operations was built with the capability to allow for future projected expansion. Several research groups, currently working with Anglo American on collaborative research over a range of projects, were brought in to review the existing operation, with a view to releasing some specific bottlenecks and providing specialist design input to the potential plant expansion.Based on a thorough review of the high pressure grinding rolls (HPGR) and crushing circuit, a wide range of de-bottlenecking opportunities were identified. This was followed by a series of surveys to provide performance measurements and to model the circuit in detail. From this effort a full simulation of the plant has been developed, including updated models of the HPGR, crusher, bins and screens. These models have been implemented in the researchersÆ Model Development Kit (MDK) version of JKSimMet, and in a prototype dynamic simulator based on the Matlab Simulink software.The observations, measurements and simulations have provided guidance and quantified the benefits of some proposed circuit modifications. Based on these findings a number of upgrades are being planned, with the aim of ensuring full utilisation of the installed equipment. The circuit demonstrates a potential expansion of over 30 per cent through minor improvements, and a 70 per cent increase in capacity with the addition of some strategic equipment.The HPGR-crushing upgrade project demonstrates the potential benefits of nurturing disparate Research groups into a strong inter-disciplinary technical team capable of supporting operational needs while developing future technology.CITATION:Powell, M S, Hilden, M M, Evertsson, C M, Asbj÷rnsson, G, Benzer, A H, Mainza, A N, Tavares, L M Davis, B, Plint, N and Rule, C, 2012. Optimisation opportunities for high pressure grinding rolls circuits, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 81-94 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By J M. F Clout

In the iron ore industry significant emphasis is placed throughout the mining process on meeting chemical composition specifications for the export of fine ores, however, little has been published on the implications of ore chemical composition for iron ore sinter and pellet product quality. The ore bulk composition, together with the nature of the minerals in the fine ore both play a critical role in determining the type of high temperature bonding phases that form during sintering and pelletising. This paper uses the experimental determination of phase relations in model sinter and pellet systems such as Fe2O3-CaO-SiO2 (FCS) and Fe2O3-Al2O3-CaO-SiO2 (FACS) to examine the links between iron ore chemical composition and the temperatures used during sintering and pellet firing. The phase relations help to establish the critical thermal and compositional parameters that control the bonding phase chemistry which in turn influences the physical characteristics of the sinter or pellet matrix. Results show that lower Fe-grade (

Jan 1, 2002

By J Bassan

The mining industry is faced with imperatives to improve worker safety and productivity, adapt to skills shortages, high worker turnover rates, and provide more effective maintenance to new and ever more complicated plant and equipment. While more effective use of data combined with advanced analytics offers opportunities for improvement, providing this information to the worker in the field, in real-time, has proven expensive, cumbersome and ineffective. New capabilities are now emerging which address some of the limitations experienced to date. Augmented reality (AR) provides a means to overlay interactive digital information on top of the physical world. Combining the latest visual display, mobile computing and ‘track and trace’ technologies, AR provides an experience similar to a heads-up display in a fighter jet through small, personnel devices, such as smart phones or wearable glasses. Applying AR would allow a mobile worker to ‘see’ all relevant information for a given task, in the context of their physical environment and at the time they require it. The technologies behind AR are rapidly maturing and becoming available at a price point that is viable for commercial applications. It is anticipated that AR will become ubiquitous at a consumer level within the next five years. The specific challenges faced by the mining industry make it an ideal early adopter of AR technologies. This paper examines a number of use-cases of how AR can be applied to the mining industry and the benefits that can be realised. The paper will identify areas of further work and viable opportunities for immediate adoption within the industry.

Nov 22, 2011

By G Cavanough, A Olsson, J Rock, A C. Torrance

There are various methods currently in use to determine detonation performance of bulk explosive products including velocity of detonation (VOD), high speed photographic analysis, fragmentation analysis and unconfined detonation of samples. For assessment prior to detonation the current practice is limited to a measurement of cup density. This paper presents additional techniques that have been developed to provide measurement and assessment of bulk explosive products. Techniques applicable prior to detonation include a mobile laboratory to allow on-site chemical and physical analysis of sensitised products and ‘in-hole density’ measurement to monitor the in-hole density during sleep time. Assessment of detonation performance is achieved using detonation pressure sensors. These sensors allow measurement of detonation pressure, average VOD, propagation time and magnitude of the pressure induced in the explosive column by detonation of adjacent blastholes.CITATION:Cavanough, G, Torrance, A C, Rock, J and Olsson, A, 2015. Measurement and assessment of bulk explosive products, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 477–484 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By N Guresin, R Dunne, S Blanco

This paper presents the results of research work conducted to assess if aqueous solutions of sulfur dioxide (SO2) can be used to treat roaster calcine leach residues such that recovery of gold in this material can be achieved with subsequent application of the thiocyanate (SCN-) leaching system. The project is mainly aimed at assessing an alternative use for sulfur dioxide gas generated during flotation concentrate roasting. The calcine leach residue sample used in the study contained 2.56 g/t gold. The reason for this high level of residual gold is thought to be due to gold surface passivation by thin iron oxide films, presence of gold in solid solution with refractory iron oxides and encapsulation of gold in the structure of these iron oxides.The study was conducted in three stages. The first stage was the characterisation of a sample from a roaster calcine leach residue. The second stage in the project was a set of leaching tests to assess the feasibility of using aqueous solutions of sulfur dioxide to reductively dissolve refractory iron oxide mineral phases contained in the calcine. The final objective was to assess the efficiency of thiocyanate, a gold complexing ligand stable under acidic and oxidative conditions, to extract gold liberated during sulfur dioxide leaching.The study showed that the reductive sulfur dioxide treatment of the calcine leach residues followed by oxidative thiocyanate leaching to extract gold was not a particularly efficient process as only around 20 per cent gold could be extracted. Leaching the calcine residues by any of these systems separately also extracted the same amount of gold (12 - 14 per cent) implying that irrespective of the solution potential, the acidity helps dissolution of gold encapsulating minerals, mostly hematite, but at a very slow rate. The findings on the topic in the literature and during this study show the requirement for further technical investigations and economical analyses on two cases. The first case is to roast gold concentrates to produce magnetite rather than hematite followed by sulfur dioxide and thiocyanate leaching of magnetite containing calcines. The second case is to apply a magnetic concentration process to conventional roast-cyanidation calcine residues to produce a gold-rich magnetite concentrate that can be further treated with sulfur dioxide followed by thiocyanate leaching.For both cases, the best evaluation of the sulfur dioxide leach system in extracting residual gold from calcine leach residues will require a detailed economic analysis to find out the balance between the value of the gold recovered and the loss of revenue from acid production. There are a number of roasters that do not produce acid. In these cases, a portion of the unwanted sulfur dioxide gas can be used to recover gold in magnetite containing calcines as an economic incentive.CITATION:Guresin, N, Blanco, S and Dunne, R, 2013. Leaching roaster calcine leach residues with aqueous solutions of sulfur dioxide and thiocyanate, in Proceedings World Gold 2013 , pp 129-136 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

Optimal drill and blast design is a process often neglected by many underground hard rock mines. This is even more important to the new mine where ring designs need to be implemented and refined in a short period of time. In today's environment where more and more mining is being carried out by contract specialists it is the co-operation between a principal and contractor, who are working towards a common goal, that achieves the highest quality end result. The development of drill and blast designs that cause minimal damage to the mine infrastructure is particularly important to Northparke's E26 Block Cave Mine, as it consists of a single extraction level which must survive intact for the life of the mine. The advanced undercut mining method implemented at Northparkes is fired in a sequence which protects the mine development from potentially damaging abutment stress. This paper details how blast designs will be optimised and sequenced to satisfy the conflicting objectives of maximum rock breakage inside the drill pattern and minimum rock damage outside the pattern.

Jan 1, 1995

By D Will

RedrossThe Redross orebody averages 1 m wide, has a strike of 50 - 350 m, dips at 55° and has a basalt footwall and an ultramafic hanging wall. The most successful and innovative aspects of mining Redross were:•ore development innovations, 90 per cent of development was split fired with a shanty back profile to enable larger and more productive equipment to be used and resulted in higher development grades, improved project payback time and improved ore recovery;•hand held stoping using a multiple level, bottom up ‘V’ shaped hand held stoping method that allowed mining on multiple levels with hand held productivities between 50 and 90 tonnes per shift;•the use of 1 m cement pillars and 7 m high crown pillars were used to create multiple mining areas that enabled high overall production rates from hand held mining this orebody; and•the use of vertical cement pillars to enable hand held mining of adjacent stopes without leaving ore pillars.MarinersThe Mariners orebody averages 3 m wide, has a strike length of 50 - 250 m and dips at 50° with a basalt footwall and poor ultramafic hanging wall. The most successful innovative ideas of re-opening Mariners were:•Dewatering the existing mine workings utilising ‘oilfield’ technology by installing a long submersible pump in on existing pump rising main. This enabled the mine to be dewatered at rates up to 100l/ sec and helped overcome the 45 to 55 L/s inflows.•Overcoming the technical problems associated with Mining N07 ore blocks which had severely deteriorated from being underwater for five years by using reverse firing techniques to improve extraction rates and reduce dilution.•Mass firing a large mining block in the N08 with minimal void space because of deteriorating ground conditions.•Use of a longhole version of the Redross hand held mining method to achieve 100 per cent extraction of the N09 higher grade lenses.

Mar 21, 2011

By A Giblett, S Hart

"In 2015 operations under the ownership and/or management of all Newmont Mining Corporation subsidiaries (Newmont) produced 5.7 Moz of gold and 619 Mlb of copper from mining operations in five countries, with well over 100 Mt of ore processed by various grinding technologies. Processing methods used in the extraction of metals include flotation, oxidation, conventional cyanidation and heap leaching. The grinding technologies applied in milling operations feeding metal recovery processes include conventional wet grinding semi-autogenous grinding (SAG), rod and ball, dry grinding, concentrate regrinding and ultra-fine grinding, and ball milling of high pressure grinding roll product. SAG/ball (SAB) configurations represent the dominant comminution flow sheet within the company and the circuit configurations employed include SAB, SABC-A, SABC-B and single-stage (SS) SAG milling, with SAG mill feed ranging from run-of-mine (ROM) ore through to secondary crusher product. The collective experiences earned from designing, operating and debottlenecking these various comminution circuits provide many lessons that can be applied to the design and optimisation of future operations. This paper provides an overview of Newmont’s diverse comminution circuits, discusses recent performance and offers some insight into optimisation and design considerations based on recent experience in both endeavours.Citation:Giblett, A and Hart, S, 2016. Grinding Circuit Practices at Newmont, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 293–302 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By I D. Gregson, A S. Garcia, K M. MacAndrew

The design work undertaken by Rock Mechanics Technology (now part of Golder Associates (Golder)) has played a major part in successfully establishing mechanised room and pillar working in Indian coalmines, both for the development of new districts and for the re-establishment of old districts prior to pillar extraction on panel retreat.Golder has used appropriate design of pillars, extraction sequences and final snook sizes to minimise ground control risks during pillar extraction. Where the strata will not cave reliably, partial extraction systems leaving either a crush pillar or a substantial yield pillar have been adopted.Remote monitoring of selected pillars during the extraction process using stress cells, extensometry and convergence measurements provides confirmation of pillar behaviour and verification of designs.A new telltale device, giving a visible warning of impending caving, is now installed at all Indian pillar extraction sites and is proving very successful.CITATION:MacAndrew, K M, Garcia, A S and Gregson, I D, 2014. Coalmine pillar design and performance during mechanised pillar extraction in India, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 347–358 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By G R. Hancock, S Grant, T Whiteside, J B. C Lowry, J Boyden, T J. Coulthard

Physically-based landform evolution models (LEM) provide a spatial framework to forecast the long-term geomorphic stability of post-mining landscapes. When used to test the relative stability of different landform designs, LEMs may assist with the development of optimal closure designs for rehabilitated mines. However, in order to reduce prediction error, factors controlling landscape evolution must also be accurately represented by models. This requires that the correct sets of processes are represented and that driving parameters used in LEMs are, if necessary, calibrated to the landscape of interest.Vegetation exerts strong controls on the hydrologic and geomorphic processes that drive landscape evolution. Hence, the spatial and temporal scales over which typical patterns in vegetation are represented in different landscapes are important considerations in LEM calibration. However, vegetation is rarely accounted for in LEMs and even when integrated is often represented simply, without representing spatial dynamics of vegetation cover that may impact landform development.This study focuses on characterising vegetation patterns to calibrate a new vegetation module of the The Cellular Automaton Evolutionary Slope and River (CAESAR)-Lisflood LEM to be applied to a conceptual rehabilitated landform of the Ranger uranium mine located in the Alligator Rivers Region (ARR) of northern Australia. In the ARR the spatial dynamics of vegetation over time are largely driven by monsoonal rains and topography. Extensive dry season fires are also common in the region, temporarily reducing vegetation cover where they occur. Hence, hydrology, topography and fire disturbance interact to shape a distinct, yet dynamic, mosaic of different vegetation types of varying cover density. As a basis for calibrating the new vegetation function, the distribution and dynamics of vegetation are characterised for this savannah landscape by remote sensing, in conjunction with ground data.CITATION:Boyden, J, Lowry, J, Coulthard, T, Whiteside, T, Hancock, G and Grant, S, 2016. Accounting for vegetation dynamics in landform evolution modelling, in Proceedings Life-of-Mine 2016 Conference , pp 63–66 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By J OÆDriscoll, R Butler, L Winter

The iron ore mining district of Labrador West and adjacent Quebec is Canada's largest iron ore producer with almost 50 years of production. The area is currently experiencing a period of renewed activity not seen in decades that includes new mine development, mine expansion and exploration for new iron ore resources. All of the past and present production and exploration programs in the district are centred on the Lower Proterozoic Superior-type iron formations of the Knob Lake Group, located within the Grenville tectonic province of the Canadian Shield. The Knob Lake Group is a continental margin sedimentary sequence which was deformed and subjected to greenschist to upper amphibolite facies metamorphism during the Grenville orogeny. Regional deformation and metamorphism plays a key role in making the iron formation of the Knob Lake Group economic. The distribution of orebodies in the district is controlled by superimposed F1/F2 synclines which causes thickening of the iron formation through repetition. Ore mineralogy consists of specular haematite, magnetite and locally martite with quartz as the major gangue mineral. Regional metamorphism has caused an increase in grain size of the ore minerals making it more amenable to concentrating and pelletising. Altius has been active in Labrador West since 2003 and is now the second largest licence holder in the district with several iron ore exploration projects. The Kamistiatusset project is located in the heart of the region's transportation, power and mining infrastructure. The property has seen limited previous exploration, but covers several significant iron ore prospects. Work by Altius includes a helicopter-borne magnetic survey, ground magnetic and gravity surveys, geological mapping, sampling and 6000 m of diamond core drilling all of which confirm both a favourable geologic setting and ore mineralogy.

Jan 1, 2009

By H Ishikawa, H Zhou, M Spagnolo, R Halomoan, S Palaniandy

The Karara Mine concentrator commenced operation in November 2012 to produce high-grade magnetite concentrate. The circuit consists of three stages of comminution plus magnetic separation at each stage for early gangue rejection. High-Pressure Grinding Rolls (HPGRs) are used for fine crushing, followed by ball mills and TowerMills in secondary and fine grinding duties respectively. In recent times, the plant throughput rate has had to exceed design by 18% to maintain the targeted concentrate productivity. Meanwhile, the ore hardness has increased by 25% to 15 kWh/t, leading to changes in the circuit operation and design. These changes led to coarser and harder feed to the TowerMill circuit that affects the subsequent separation processes. Nippon Eirich (the TowerMill manufacturer) has partnered with Karara Mining Limited (Karara) to optimise the TowerMill circuit operation to achieve a circuit product with an 80% passing (P80) of 35 µm. Several activities, including a TowerMill circuit audit and performance evaluation, multi-component analysis, modelling and simulation, were carried out as part of the optimisation exercise. The circuit audit results revealed that the TowerMill circuit feed size F80 had increased and ranged from 67–75 µm. The circuit product P80 ranged between 42–55 µm. The average circuit specific energy was 3.4 kWh/t. Moreover, the differences in density between magnetite and gangue minerals had affected the hydrocyclone performance where the efficiency curve exhibits coarse end deflection indicating that low-density coarse material was bypassing to the overflow stream. A multi-component analysis was carried out to further investigate the coarse end deflection of the hydrocyclone efficiency curve. The analysis showed that the magnetite and gangue minerals had different cut sizes of 32 and 64 µm respectively. Furthermore, 33% of the magnetite (below 35 µm) was being recycled back to the mill due to the density effect. Based on these findings, several recommendations for process improvement were identified and implemented including:• converting to a bottom feeding configuration to improve the grinding efficiency in the mill• additional grinding power in the fine grinding duty to compensate for the increase in plant throughput and ore hardness• improved classification efficiency by converting to smaller size hydrocyclones. Simulation studies carried out to evaluate the impact of these implementations had indicated that a P80 close to 35 µm with a steeper size distribution could be achieved by using the bottom feed configuration with additional grinding power. The TowerMill circuit was converted to bottom feed configuration and the performance was evaluated. The operating work index, size specific energy and circulating load were 30% lower than the top feed configuration, indicating that the bottom feed configuration had a higher grinding efficiency. This paper discusses the outcome of the circuit audit, multicomponent analysis, circuit simulations, improvement strategies and quantification of the improvements. CITATION:Palaniandy, S, Spagnolo, M, Halomoan, R, Zhou, H and Ishikawa, H, 2017. Fine grinding circuit process improvement at the Karara mine concentrator, in Proceedings MetPlant 2017, pp 101–120 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

During operations, mining and metallurgical processes may generate effluents such as tailings water, acid mine drainage (AMD) and seepage and process acid streams. Depending on the type of ore and the metallurgical process, these effluents may contain one or more toxic compounds (eg acidity or alkalinity, cyanide, ammonia and/or nitrate, heavy metals, total suspended solids (TSS), sulfate) in elevated concentrations requiring treatment before their discharge to the environment or recycle/reuse in the process. Natural oxidation of sulfide minerals present in mining wastes (eg tailings and waste rock) at mining sites may generate AMD, which is characterised as a low pH, high acidity effluent containing heavy metals and sulfate. If generation of AMD cannot be controlled and/or prevented, AMD needs to be collected and treated for neutralisation of acidity and reduction of metals and TSS to meet regulated water quality standards. It is important to note that some of these compounds may persist in run-off from mine sites, even after the mine and processing facilities are decommissioned. Treatment of mining and metallurgical process effluents can be accomplished by means of various physical, chemical and/or biological methods. The mode of process application may vary from the use of either specifically designed, controlled and automated facilities or passive systems. Lime neutralisation and precipitation is the most common method used in the mining industry to treat AMD. To reduce the problems associated with disposal and long-term storage of the resulting sludge, the use of a high-density sludge process (HDS) has become a preferred option. The use of other chemical reagents, waste or by-products from other industries, and biological sulfate reduction methods can also be considered as viable options for site-specific situations. Recently, several passive treatment systems have been designed and successfully operated, even in the cold North American climate. This paper will discuss available options and provide insights for selecting a suitable method for a given situation using case studies from projects conducted by Golder Associates around the world over the last decade.

Jan 1, 2006

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 R C. Schodde

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Over the last decade (2005–2014), a total of 439 significant deposits of gold and base metals were found in the world. Twenty (or 4.6 per cent) of these deposits were in the Pacific/South-East Asia (Pacific/SE Asia) region. In terms of contained metal, the region accounted for 1.6 per cent of gold and 13.8 per cent of copper found in the world. With regard to nickel and zinc/lead, the region’s contributions were insignificant.Over the same period, the Pacific/SE Asia region accounted for 6.6 per cent and 12.6 per cent of all gold and copper exploration expenditures in the world respectively. After adjusting for by-product credits, unreported discoveries and likely growth in resource, the unit discovery cost for the region was US$199/oz (compared to a world average of US$50/oz). For comparison, the unit discovery costs for the previous decade were US$55/oz and US$25/oz respectively. The region’s unit discovery cost for copper was US$0.036/lb (versus a world average of US$0.040). For comparison, the unit discovery costs for the previous decade were US$0.026/lb and US$0.008/lb Cu respectively.The region’s mediocre discovery performance doesn’t reflect its distribution of known mineralisation. Some countries within the region have a very good endowment per square kilometre.It is noted that the intensity of exploration (and resulting success) would be boosted if governments provided a more mining- and investment-friendly business environment and generated better precompetitive geological data sets (to identify new exploration targets and boost the country’s perceived mineral prospectivity). A multivariable regression analysis of a decade of data from the Fraser Institute’s mining company surveys found that a ten point increase in the Policy Perception Index or a 0.1 point increase in the Mineral Potential Index could boost (in the short term) exploration expenditures by 1.9 per cent and 2.7 per cent respectively. The resulting economic benefits of an expanded mining sector would be significant. The same story applies elsewhere in the world.CITATION:Schodde, R C, 2015. Discovery performance for gold and base metals in the Pacific/South-East Asia – 2005–2014, in Proceedings PACRIM 2015 Congress, pp 25–34 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By A M. Lechner, S Arnold, M J. Gillespie, P D. Erskine, D R. Mulligan, A T. Fletcher, A Gordon

Mine ecological monitoring schemes are often conducted only to address compliance and in some cases do not have the sufficient statistical power or understanding of ecological systems to assess, quantitatively, the meeting of rehabilitation targets or mine impacts. Monitoring schemes for rehabilitation commonly rely on analogue sites or premining baselines (reference sites) to assess whether rehabilitation sites are ecologically similar and thus successfully rehabilitated. In the case of monitoring for mine impacts, if the impacted sites diverge from reference data, the site is considered to be impacted. Fundamental to any monitoring scheme is testing the sampling design to ensure that it can detect these differences if they are present through adequate sample sizes (ie statistical power). However, a good understanding of the ecological system is required to ensure that differences detected are ecologically significant. Modelling ecosystem properties can provide a quantitative understanding of how ecosystems change over time and space, in response to natural environmental variations and thus aid in determining significant ecological differences. Furthermore, modelling methods can be used to predict future ecosystem states. Within the ecological literature, guidelines for robust statistical monitoring designs and modelling methods exist but are not routinely being used in the mining industry. This paper uses simple examples to discuss: problems with current compliance monitoring methods; importance of robust statistical techniques; and how modelling can assist rehabilitation assessment and guide monitoring schemes. The aim of this paper is to describe general monitoring and modelling methods that could be potentially used for mine site monitoring and closure assessment. These methods are often considered by mining companies as an extra expense that provide little practical benefit, and the domain of academia; however, engaging these methods may be more cost-effective in the long-run than conducting untargeted monitoring schemes that give no confidence to regulators on whether rehabilitation criteria have been met. Furthermore, monitoring programs in mining contexts provide a good opportunity to better understand long-term ecological patterns and test the application of more rigorous modelling approaches as the life of many mines tends to be greater than ten years.CITATION:Lechner, A M, Arnold, S, Fletcher, A T, Gordon, A, Erskine, P D, Gillespie, M J and Mulligan, D R, 2012. Embracing modern ecological methods - Monitoring and modelling for mine closure, not compliance, in Proceedings Life-of-Mine 2012 , pp 25-32 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

The weathering profile, in arid terrains, is commonly capped by different kinds of hardened crust, whose formation is related to recent or former climates. One may distinguish silcretes, calcretes and the ferruginous (or ferro-aluminous) laterites. the present keynote address mostly deals with the lateritic regolith and, moreover, the influence it has on mineral exploration. The lateritic regolith, also called "cuirasse", is a result of a massive accumulation of Fe (and/or Al) oxides on top of weathering profiles developed during former, probably seasonal humid, climatic episodes, and whose preservation depends on the characteristics of later climates. The total thickness of such weathering profiles commonly exceeds 50 m, with an almost complete substitution of the rock forming minerals by secondary minerals as kaolinite and Fe-Al oxi- hydroxides (hematite, goethite, boehmite, gibbsite). Such an alteration of the primary minerals assemblage is of course accompanied by significant changes of the chemical composition, as concerns major and trace elements. The latter are distributed amongst the main secondary mineral phases or trapped in some primary resistant minerals, but may also be leached, totally or partially. Gold is also affected by lateritic weathering, as shown for instance by morphoscopic and geochemical studies of gold grains collected in the different horizons of the profile, which indicates some dissolution followed by reprecipitation.

Jan 1, 1988

By C Nyoni, T Nguyen, C R. W Seymour, G D. Dempers

Unplanned dilution directly adds cost to production from mining, milling, tailings disposal and administration. Additionally, unplanned dilution decreases the productivity, profitability and may affect the planned life of mine. Identifying and quantifying the potential for unplanned dilution allows optimisation of the mining plan and mining practices to minimise the adverse impact on productivity and the cost of production. The Dilution Rating System (DRS) has been developed to more accurately predict dilution thickness and the variable potential for dilution, from individual stopes to life of mine planning. The DRS utilises the methodology developed for the Mining Rock Mass Model (Seymour et al 2007, Jenkins et al 2009) to generate a three-dimensional dilution rating model, which is then calibrated against stoping performance. Dilution can be predicted more accurately and the parameters affecting dilution can be determined and minimised through improved mining techniques, for example blasting and ground support design. Potential high dilution areas can be identified in the planning stages of the mine and systems put in place to mitigate the risk of excessive dilution. This paper presents the methodology used to develop the DRS and then successfully predict dilution for both the hangingwall and footwall of stopes at the Gara Gold Mine. This has enabled the expected dilution to be more accurately predicted and mitigated where possible thus reducing unplanned dilution.

Mar 15, 2021

By J Siliézar

The Ernest Henry Mine (EHM) is situated 38 km north-east of Cloncurry in the Mount Isa – Cloncurry mineral district of northwest Queensland. The EHM orebody is an iron oxide copper gold deposit with an average grade of one per cent copper, 0.5 g/t gold and 23 per cent magnetite, with current reserves of approximately 88 Mt.The copper concentrator is a single line plant with a nominal throughput rate of 1300 tonnes per hour. An average of 350 000 tonnes of concentrate is produced each year containing around 100 000 tonnes of copper metal and 120 000 troy ounces of gold.In December 2009, Xstrata Copper announced approval of a $589 M investment to extend the life of EHM to at least 2024, through the transformation of open pit mining operations to a major underground mine together with the construction of an associated magnetite extraction plant.The EHM magnetite plant extracts the magnetite from the copper concentrator’s tailings stream. It will produce approximately 1.2 Mt of magnetite concentrate per annum at full capacity for export to Asia, making EHM Queensland’s first iron ore concentrate exporter. Construction of the magnetite extraction plant commenced in July 2010 and was completed in January 2011.This paper gives an overview of the development of the EHM magnetite extraction plant flow sheet from the early mineralogy and laboratory test work through to the plant commissioning and early operation of the base plant. It has a major focus on the commissioning learnings from the plant start-up and includes a review of the operational performance of the plant versus original design and expectations.

Jul 11, 2011