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By S B. Fitch, S A. Wilson, A J. R Barr, P R. Searle

Improving the safety culture and performance of any operation is a fundamental goal of every mine operator. Methods of implementing, or changing a culture have developed from the early methods of operant conditioning, for example rewarding crews for achieving nominated safety milestones i.e. 3 months Lost Time Injury (LTI) free through to the current model of engaging a workforce through education and empowerment. As a large scale and mature operation with multiple contractors, Telfer has been exposed to numerous programs throughout its history. This has provided the opportunity to build on and complement these systems by integrating key elements from each. SAFE 360° is a new approach developed to engage the workforce in a holistic approach to encourage positive behaviours across all facets of an individual’s life which results in a focus on situational awareness at all times, rather than being workplace specific. It is based on three key modules: • Emotional Intelligence • Mindfulness • Situational Awareness Each module has a series of modules that help enhance the individual’s sense of self, leading to an ability to self-reflect and self-manage whilst empowering them with the moral courage to challenge their peers to raise standards. Since commencing this SAFE 360° behavioural safety risk management journey in November 2017, we have witnessed a change in the way our workforce engages with each other, their workplace and with management. There has been an increase in hazard perception, identification and ownership of issues, and we have seen a significant decrease in site TRIFR rate from 13.7 to 5.7 (as of April 2019). This paper will provide an overview of the program, how it has been implemented, case studies to demonstrate outcomes and KPIs used to measure effectiveness.

Mar 15, 2021

Brand se Baai, on the North-Western Cape Coastline of Southern Africa, is the site of the Namakwa Sands Limited Heavy Mineral Sands Mining Operation. The mine is a 14 000 000 tonnes per annum open-cast strip-style mining operation using truck and excavators to mine the sand. The orebody consists of relatively unconsolidated sands reworked by fluvial, marine and aeolian mechanisms. The total orebody includes three primary ore types, namely the Red Aeolian Sands, the Dorbank (a hardcap layer) and the Orange Feldspathic Sands, which forms the bulk of the resource. Mine planning and scheduling is done using a 50 m + 50 m variable bench height system with three primary bench heights. The Aeolian and Dorbank each have a bench that varies with their thickness of up to a maximum eight metres and the Orange feldspathic sand, a standard bench height of eight metres. For a number of years Namakwa Sands used a complex 2D, Datamine Based, macro system to perform the resource evaluation and mine design. As the mining operations expanded it became clear that a complete system redesign was required to cope with the increasing operational pressures coming to bear on the old system. The biggest challenges facing any replacement system are the sheer scale of the mining operation (16 km long and 7 km wide resulting in a minimum of 30 000 individual 50 m + 50 m mining blocks), the size of the geological data files (up to one gigabyte) and representing the benching system accurately (as the benches follow the topography and are not horizontal). In addition to these large-scale issues, the ability to run multiple mine design scenarios was required, an aspect which the old system was unable to perform adequately. Based upon these primary difficulties, a new business process was developed which required a complete rethink of the mine design methodology as well as the creation of a new system to deplete the resource model, produce monthly reconciliation evaluations and create a ultimate pit limit based on the operations mining cost model. Using a system based on the Earthworks Mine2-4D Mine Design and Scheduling System (with its mine design and scheduling specific tools), as well as a small, customised program, massive time-savings have been made. It is now possible to run several life of mine scenarios in the same timeframe that a single life of mine run took under the old system. This paper will present the methodology and business decisions behind the new Namakwa Sands system, and detail the restructuring and development used to deal with the large data set sizes and long processing times inherent in the old system. Future enhancements to the system that will make it more generically applicable to open-cast mining scenarios will also be dealt with.

Jan 1, 2003

By J Field

Many aspects of water use in mining are driven by the technical requirements for water. There has been little consideration given to both the safety and the health requirements. Workers in the mining industry are exposed to water from a range of treated and untreated sources. The intended use of this water dictates the required quality of the water, sometimes with limited consideration for contact with miners. Particularly for underground workers, there is exposure while working in and walking through groundwater possibly contaminated by hazardous substances. Where controls are inadequate the outcomes of this exposure can result in disease, illness and injury û the costs of which can be significant. The situation could also arise where, due to the lack of human exposure, the controls are unwarranted and the financial cost unjustified from a health perspective but warranted from an equipment management standpoint. In addition to the health aspects, water can impact on a range of safety issues resulting from high pressure usage, dust suppression, fire fighting and other processes. The protocols and procedures in place need to consider the safety issues in addition to managing water usage. The current state of water management in mines from an occupational health and safety perspective has been ascertained from a survey targeting underground and surface coal and metalliferous mines. This survey considered the health and safety issues associated with water use, the types of surveillance, control protocols and the strategies that the mines have in place to manage the health and safety risks associated with water systems. The results assisted in the identification of potential occupational health and safety risks associated with water systems and the management processes that may be appropriate from a risk management perspective. Health and safety issues are often neglected but remain critical issues affecting the value of water to the mining industry.

Jan 1, 2006

By Denby B

The ever increasing demand on land use has led to large areas of land being considered for development, which because of past mining activities are covered by substantial depths of fill materials. This paper examines the problem faced with the development of land infilled with open cast mining backfill, in predicting the behaviour of the fill upon development. To be able to design foundations suitable to withstand the movements that occur within open cast backfills or design a backfilling operation that produces land suitable for a proposed after development, a means of predicting backfill settlement is required. Factors critical to this prediction are the timing of backfilling operations, the compactive state of the backfill and the inundation of the backfill. The analysis of a considerable quantity of data collected from the monitoring of backfilling operations and backfill movement at a range of open cast coal sites located within the UK has given the authors a better understanding of how open cast backfills behave in terms of long-term creep settlement, collapse settlement and how these are effected by backfill scheduling. This knowledge has been encoded into a program running under Microsoft Windows that enables a user to make settlement predictions for a point, a given section or area or for the whole site. Differential settlements, critical to any development design, can also be determined between any two points taking into consideration the heterogeneous nature of open cast backfills. The program was tested with data from an open cast coal site in the UK. Compaction monitoring during the placement of the backfill material enabled a model of the backfill to be constructed taking into account backfill properties and scheduling. This model, taken as input into the program, enabled future backfill settlement predictions to be made. A comparison is given between these results and actual settlements obtained from a short-term settlement monitoring scheme.

Jan 1, 1995

By T M. Nester, D J. Reardon, A N. Page, B J. Barsanti

The load capacity of a friction bolt has long been regarded as 4 t/m of embedment for ground support design analysis and supported by in situ pull test results. In recent years, the authors have observed lower pull test results or inconsistent results which were rarely sighted in the early 2000s. The lower pull test results indicated in some cases that reliable friction bolt capacity (≥90 per cent of results) is closer to 3 t/m of embedment with some geotechnical engineers adjusting the ground support parameters in the design work accordingly. This can be in contrast with other mines which reliably obtain 4 t/m (or greater) using the same suppliers bolt in similar ground conditions. This raised several questions: • What is the effect of poor installation (bolt twist or bolt hole deviation)? • Does the performance of friction bolts vary in different rock masses? • Does bolt performance vary between suppliers? • What effect does increased jumbo feed/percussion/rotation settings have? • Have the bolt dimensions or steel strip width changed? • Have the physical bolt properties changed? • Have the steel properties changed? This paper was aimed to answer as many of these questions as possible and discuss each variable in detail. This project included friction bolt trials at various mine sites across Australia, multiple friction bolt manufacturers, steel manufacturers and laboratory analysis. The paper also includes discussion on what the authors consider best practice for pull testing. It should be noted, the terms ‘friction stabiliser’ and ‘split set’ used in this paper are used in a generic manner and is not linked to any specific ground support supplier. Whilst its acknowledged within the industry the term split set and friction stabiliser is used interchangeably, the authors acknowledge that the term split set is a trademark of Split Set Mining Systems and has been used in context in this paper.

Nov 29, 2022

During 2009 the technical services staff at Barrick Gold Corporation's Australian Business Unit conducted a review of their five underground mines that utilise pastefill as the backfill component for these operations. Of the five mines reviewed three use dry tailings and two use wet tailings plants. The primary aim for these reviews was to determine whether pastefill was the right option to be used, and if not, what where the alternatives. The reviews undertaken focus on several areas including, paste plant operation, reticulation and barricade techniques, the geotechnical requirements for pastefill in regards to the current mining methods, the consideration of alternative methods, capital and operating cost histories compared to initial estimates, and a cost benefit analysis of pastefill against other mining methods. The main benefits from the use of pastefill is increasing the extraction of the resource, reducing or eliminating the need to leave pillars. In some mines the use of pastefill is geotechnically driven, to manage high stress environments or mining induced seismicity. A third benefit of using pastefill in some circumstances is that it reduces dilution, however it is considered that this is not a valid argument for most of the mines reviewed. At two mines no alternative to pastefill was determined, whilst differing extraction and filling strategies were potentially identified at the other three mines. The reviews developed cost benefit curves for those sites that had alternative mining methods to assist in determining whether pastefill is the right option to use for any particular stope. At the grades typically mined in each operation, pastefill was the preferred option to use. In all mines, pastefill was determined to be the best option at this time.

Nov 25, 2010

By Kagl J, Publlier M, Nekitel S, Arumba J, Rangin C, Mosusu N

Since the advent of plate tectonic modelling, the Ramu-Markham valley has been thought the site of a classical island-arc/conti- nent collision zone. In this interpretation the units south of the Markham Valley are held to be island are / micrcontinental mate- rial accreted to Australia and those north of the valley are thought to represent a separate Finisterre island-arc terrane. Recent remapping by the Geological Survey of Papua New Guinea shows: (1) there is no terrane boundary along the Ramu-Markham valley (2) the Finisterre Volcanics are probably part of either a fore-arc sequence or oceanic plateau obducted onto a microcontinent/ volcanic-arc composite terrane, accreted to the continental Australian plate. A new tectonic model is proposed for northern PNG and involves: (I) Eocene to Late Oligocene subduction below a microcontinent remote from Australia to produce the Sepik are and related intrusives, the Finisterre Volcanics (fore-arc or possible oce- anic plateau), together with the Alife blueschist. (2) obduction of the Sepik arc in Late Oligocene-Early Miocene times over the advancing Australian plate. This resulted in crustal melting, some of the products of which are the Mid- dle to Late Miocene Akuna and Bismarck intrusive complexes of the Maramuni arc. (3) obduction of the Finisterre Volcanics began in Early Pliocene times and continues today. (4) post-Middle Miocene mineralisation is the result of melting after obduction of the Sepik microcontinent.

Jan 1, 1997

By D Wei

Large tonnages of low-grade haematite ores need to be treated every day in China. One of the mineralogical characteristics of these haematite ores is that the grain size of haematite is smaller than that of quartz and is not uniform in the ores. Therefore, a flow sheet consisting of gravity concentration, low-intensity magnetic separation, high-intensity magnetic separation and reverse flotation is mainly used to separate haematite ores in China, to obtain acceptable beneficiation performance and reduce the operating costs. Nowadays, whether based on mineral processing practice or theoretical analysis, the results show that the application of the above-mentioned flow sheet is able to take full advantage of these mineral processing methods and achieves satisfactory benefi ciation of haematite ores. For example, when the iron grade of the haematite ore is about 29 per cent Fe, a concentrate assaying 68 per cent Fe can be obtained and the recovery of iron is over 80 per cent. In the future, research work on the beneficiation of haematite ores should focus on investigating the most feasible particle size for gravity concentration circuit feed so that the operating costs can be reduced and ultimately the separation performance can be improved.

Jul 11, 2011

By K L. Avarmaa, M A. Rhamdhani, A D. P Putera, H T. B M Petrus, G A. Brooks

Multistage slag treatment was carried out to investigate boron removal from metallurgical grade silicon. Boron is known to be one of the most difficult elements to remove from silicon. Depending on boron initial concentration, boron can be removed from silicon into certain level; most previous studies have attained final 50–100 ppmw (parts per million weight) boron in the silicon using slag treatment. The term ‘multistage’ refers to a process where the resulting silicon from the initial slag treatment is further refined multiple times using a new slag. In this study, an initial slag composition of 45CaO-45SiO2-10Al2O3 (wt per cent) was utilised. Using this technique, boron level in the silicon was expected to be gradually lowered because the new slag will always have more capacity to reach the equilibrium distribution coefficient (LB = (ppmwB)slag/(ppmwB)Si). The current study was carried out through combined thermodynamic calculations (using FactSage™ ver 8.2, by Thermfact Ltd, thermochemical package) and high-temperature experimentation. The thermodynamic calculations were carried out for reactions at 1500, 1550, and 1600°C for three different scenarios: 1. Single stage refining with varied slag to Si ratio. 2. Multistage refining with slag to Si ratio of 1:1. 3. Multistage refining with slag to Si ratio of 2:1. The multistage experimental work was carried out at 1550°C under inert gas atmosphere each time for 2 hrs, with slag to Si ratio of 2:1. The simulation results indicate that the boron distribution coefficient stay essentially constant with varying slag to Si ratio and temperature, around 1.8 to 2, and the experimental results measured LB in the same range, between 1.5 and 2.5. By harnessing this feature, the simulation showed that boron can be removed by approximately 78 per cent in each stage. The experimental result confirmed that the boron concentration in the silicon was reduced by a total of 97.8 per cent from its initial value using four stages of slag treatment, from initial 270 ppmw down to 6 ppmw.

Aug 21, 2024

By Boyd GL

Backfill applied to highwall mining is foreseen as a means to increase recovery of mineable coal to levels comparable with underground longwall mining. This paper describes the progress of research to demonstrate the role required of backfill to achieve real increases in coal rCCOvCrCd h\ hi'eh ss-all mining methods.

Jan 1, 1998

The Hail Creek coking coal deposits are situated in Central Queensland, inland from the port of Mackay. A joint venture of Australian and Japanese companies has been formed to examine the feasibility of developing these deposits for sale on the overseas markets. The project envisaged involves large scale mining operations and on site benefic- iation to wash the coal to marketable quality. Infrastructure items include a 140 kilometre railway to the coast, a port facility, and at Ilail Creek, power and water supplies, roads and communications, and accommodation for a substantial workforce. The need for town development and the responsibility for the development are established. The town planning implications of coal production at the rate of five million long tons of washed coal per annum from open cut and underground mines are considered. A procedure for estimating the size of the town is expounded and the town size is determined. The factors influencing site selection are explained and a site is suggested. A method of designing the town is described and comments are made on developmental aspects. Spaciousness and preservation featuring the natural environment will be the theme of the town development.

Jan 1, 1973

By B M. Patterson, A J. McKinley, M E. Grassi

Large-scale column experiments were undertaken to determine the effect of a step decrease in groundwater pH on metal remediation by bioprecipitation. Metal contaminated groundwater at pH 5.5 was amended with ~1 g/L of ethanol in one column using a polymer mat ethanol delivery system to promote bioprecipitation, while another column was left unamended and used as a control. Sulfate reduction and zinc removal were observed after eight weeks. Zinc removal was observed in the zone of sulfate reduction, indicating precipitation as ZnS, while, copper was removed in the denitrification zone. Once steady state bioprecipitation of zinc had been established, the pH of the metal contaminated influent groundwater was decreased stepwise from 5.5 to 4.25. As a result of the change in pH, a significant increase in copper concentration was observed in both columns. In the ethanol column, the zones of denitrification and copper removal migrated up the column, while both sulfate reduction and zinc removal ceased. Bioprecipitation of metal contaminated groundwater via sulfate reduction was shown to be an effective remediation strategy for zinc removal. However, this in situ biological remediation process was sensitive to changes in groundwater pH.

Jan 1, 2004

This paper aims to address the issue of the public's image of the extractive minerals industry. What is it about the industry that incites such negative feelings and are they justified? Are we really the 'rapists of the land' that many would have us believe? Has the industry really not improved since the old gold boom days?   I believe that the fundamental cause for the public's view is lack of knowledge and understanding of the industry as a result of the dislocation of the end production from its source. There are few people who look at a house, car, record, toilet, tooth-brush, bottle of coke or pair of glasses and see the mine site that supplied the source material. But the mine site and its products should be inseparably linked. This is one area where we should be educating the public û it is all very well being anti-development but the population as a whole is not really prepared to live without its 'mineral'-derived necessities. It is very easy to say that we do not want minerals development in New Zealand but are we prepared to live with the consequences, ie go without its products? We have a duty as a global citizen to develop our own resources rather than expect Third World nations desperate for overseas investment, often with governments who are not prepared to constrain or control their development, to be exploited. New Zealand is not the only 'beautiful' place in the world and we should be aware of the impact that our demands for resources have on the countries who supply us. We have a duty to be a good global citizen.   So how does the industry improve its public image? The key here has to be to educate. This does not have to be high powered or expensive but can be as simple as getting a few local kids' hands dirty panning, and gaining some firsthand knowledge of the industry. The industry also needs to be more pro-active in the public arena. Yes, the industry has skeletons, but the industry should be publicly displaying them û admit that things have gone wrong but let's do it ourselves and not leave it up to the environmental groups to accuse, point the finger and put the industry under public scrutiny. The industry should also be publicising its successes, inviting the local press, councils, etc to view the latest area rehabilitated. But more than anything else we must tell the public what the minerals industry means to New Zealand. Can they really live without us?

Jan 1, 1991

By R R. Lovel, G J. Sparrow

Currently there are large reserves of good quality iron ore near to existing infrastructure that are not being developed because the phosphorous levels are above acceptable market specifications. Since the high phosphorous content is considered to be mainly associated with the goethite fractions of the ore, attempts were made to leach the phosphorous from the ore after a heat treatment to dehydroxylate the goethite. Heating the ore and leaching with 40 g/L NaOH lowered the phosphorous levels from 0.145 wt per cent P to 0.075 wt per cent P or lower, but a heating temperature over 800¦C was required to achieve this reduction in phosphorous levels. However, when sodium hydroxide was added to the iron ore before the heat treatment, similar phosphorous removal was achieved with a heating temperature of 300 - 350¦C. It was considered that dehydroxylation of the goethite in the presence of the hydroxide makes the phosphorous available for removal with a water leach. As well, 50 per cent of the silica and 60 per cent of the alumina in the ore were also removed in the leach, but some sodium remained in the leach product. Further work is required to remove the residual sodium to produce a marketable product.

Jan 1, 2009

By I Elias, E Moya, S Chaffer

This paper is based on a case study from a mine site that operates two gyratory primary crushers. These crushers were encountering problems, which included inconsistent P80, reduced liner life tonnage and, on some occasions, catastrophic failure of the liners.As part of an evaluation process, both crushers were ‘mapped’ using a technology for condition monitoring and modelling of the crusher’s wear components. The technology provides comprehensive coverage of the crusher’s concaves and mantle at 100 mm intervals. It also automatically assesses wear rate between inspections and determines the highest wear areas. Outcomes include projected optimum reline dates at target replacement thicknesses, the identification of asymmetrical wear patterns, and the accurate measurement of open and closed (OSS/CSS) side settings.A comprehensive study was performed to optimise the performance of both these crushers at site. Over a period of seven liner service lives, the strategies to improved performance included liner analysis (concaves and mantle profile analysis), tonnes per day (t/d) and tonnes per hour (t/h) analysis, mantle reutilisation, detection and control of loose concaves, and detection and control of uneven wear and hot spots.These strategies resulted in the improved mechanical and operational performance of both crushers through concave and mantle redesign, OSS/CSS control, accurate wear forecasting plus other initiatives.As a result of these initiatives, the site now experiences benefits which include consistent product size, increased tonnes per hour (t/h) for both crushers and the liner life tonnage has doubled. Additionally, further benefits include less downtime for crusher liner maintenance and the reduced cost of inventories by mantle reutilisation.CITATION:Elias, I, Chaffer, S and Moya, E, 2015. Improvements in service life and cost reduction for gyratory primary crushers through mantle and concaves optimisation – a case study, in Proceedings Iron Ore 2015, pp 115–128 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

The Yabulu refinery of Queensland Nickel Pty Lld near Townsville now imports more than three million wet tonnes per year of nickel laterite ore from New Caledonia and Indonesia, making it the largest importer of any commodity in Australia. The project has illustrated that importing untreated bulk ore and re-exporting high value products makes good economic sense for the company and the nation.The economics of this exercise were considerably enhanced in 1994 by changing the project's principal product from nickel-oxide sinter to refined high-purity nickel metal. It is one of the few operations in the world where nickel ore is transformed to nickel metal at a single site.Several novel technological processes were developed at Yabulu and incorporated into the refinery to allow this product transition to occur. By utilising internally developed technology the new processes were installed at a capital cost of less than $10 million. It is unique for a large nickel producer to change completely the quality of its entire product range many years after the plant was constructed and considerable attention to marketing the new products has been required.The changes have meant that the project is no longer limited to selling lower-value oxide sinter to a relatively small number of large stainless steel mills. In the past year sales of the new high purity nickel metal products have expanded to include a broad range of international customers in the special alloy, foundry and chemical industries.

Jan 1, 1995

By Schaap W

A test on Taylor's rule of mine life using published data on open pit porphyry copper mines confirmed that mine life is, on average proportional to the fourth root of reserve tonnage. Deviations from this rule-of-thumb occur to a large extent as variations between regions that are qualitatively explained in terms of differences in grade, infrastructural needs or special taxation effects.

Jan 1, 1984

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 F H. Henrfquez, A G. Oroz

Design and operating conditions of large size mechanical flotation cells were evaluated by comparing them with actual operating conditions in a plant. The objective was to determine the time scale-up factor, typically based on empirical rules. Experiments were conducted on the rougher flotation circuit at Minera Escondida Ltd. The circuit consisted of self-aerated mechanical cells of 160 m3, arranged in six parallel banks with nine cells each. The rougher circuit flotation kinetics were evaluated from direct sampling and local mass balances around each cell of the bank. Adjusted overall mass balances were also developed. This information was used to fit different kinetic flotation models, and it was found that the rectangular distribution function was the most appropriate to describe the distributed rate constant for industrial operation. Then, a rougher flotation simulator was developed to describe the actual operation in terms of the operating variables (mass flowrate, solid percentage, feed grade) and the actual volumetric flowrate entering to each cell. In this study feed pulp samples were taken in parallel from the rougher circuit and were simultaneously floated in the laboratory. The kinetic behaviour was then modelled at a laboratory batch scale in order to determine the time scale-up factor between laboratory batch flotation data and industrial size flotation. The time scale-up factor observed for large sized cells, 160 m3, was found to be reasonably similar to those previously determined for self-aerated mechanical cells, but of lower size, operating at similar recoveries. In addition, the relative effect of mixing, between laboratory batch and an industrial flotation bank, was quantified by the parameter, separating the impact that kinetic and mixing changes have on the time scale-up factor. In general, the rougher flotation operation was found to reach the predicted metallurgical target, and the optimal separability criterion was also respected. The diagnostic generates information about the internal state of the process and helps to identify potential improvements for design, operation and control of the circuit.

Jan 1, 2005

By C A. Myburgh, S Craig, K Deb

In focusing on open pit mine scheduling, one of the biggest areas that a mining engineer can add value is in the area of cut-off grade optimisation. It is not atypical to add up to an extra 20 per cent in value by bringing forward higher-grade ore and deferring costs into the future.There are many techniques available to maximise net present value (NPV) when applied to open pit mine scheduling. That in itself raises the question of why so many of these techniques exist. The short answer is that none of these techniques are robust. Every time the problem changes, the algorithms also have to change.Instead of trying to make a problem fit the constraints of an existing technique, there is much to be said for usefully hybridising different approaches. This paper describes an innovative approach where evolutionary algorithms are combined with both local search and linear programming. The goal is maximising NPV through optimisation of cut-off grade policy and extraction sequence for an open pit mine. The cut-off/cut-over grade policy produced caters for multiple processing streams and stockpiles.Finally we demonstrate the quality of the algorithm by comparing some results with a well-known mathematical solution.CITATION:Myburgh, C A, Deb, K and Craig, S, 2014. Applying modern heuristics to maximising net present value through cut-off grade optimisation, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014, pp 155–164 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014