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By Moeller T

The Bottle Creek mine, when opened next month, will consist of three open cuts, Emu, VB and Boags, feeding ore to a central mill. The open cuts cover a strike length of 4.5 kilometres which forms part of a linear structure, which can be traced geochemically for 26.0 kilometres. With the exception of a few small gossanous outcrops at Emu, the deposits are completely covered with insitu laterite and alluvial overburden. Since its discovery in 1984, the deposit has been subjected to three major reverse circulation (RC) drilling programmes which have successively closed up the drill spacing on the main mineralized zone to 25m horizontally and less than 25m vertically. All resource calculations have been based primarily on samples of RC drill cuttings from these programmes. Ore reserve calculations have been completed after each drilling phase. They began with a simple polygonal technique, progressed through two sectional half-distance calculations and are now being completed with a 3-D geostatistical technique. Because of the style of mineralization, Norgold personnel paid particular attention to assessing the variability of the mineralization by using repeat samples, repeat analysis and diamond drill vs RC comparisons. In addition, close attention has been paid to obtaining an accurate estimate of the global SG of the ore bodies. Particular care has been taken to obtain complete drill intersections of the orebody and to maximize wet sample recoveries. Extensive re-sampling and re-analysis of samples has confirmed that Bottle Creek is unusual for an oxidized gold deposit in that all the gold appears to be very fine grained, and evenly distributed within the mineralized zone.

Jan 1, 1987

By A Scott, I Onederra

Most iron ores occur in mine benches as complex mixtures of lithologies and ore types. This significantly complicates their characterisation for both blast design and fragmentation modelling. A great deal of technical and research effort has been applied to the development of models to predict fragmentation from rock blasting. A number of quite useful engineering models are currently available to blasting engineers and consultants, and more sophisticated approaches using mechanistic descriptions of rock breakage continue to be developed and applied by researchers and explosives companies.The engineering or empirical models that are in more general use within the industry, such as the Kuz-Ram model, require appropriate data if they are to generate useful fragmentation predictions. Some of these models have reached significant sophistication and have made very useful contributions to both routine blasting operations and the exploration of new blasting paradigms. However, these models struggle to adequately deal with rock that is as complex as iron ore. This paper reviews the characteristics of the most successful blast fragmentation models available to the industry and discusses approaches to the derivation of suitable rock mass properties to adequately describe blast fragmentation in a range of iron ores.CITATION:Scott, A and Onederra, I, 2015. Characterising the blasting properties of iron ore, in Proceedings Iron Ore 2015, pp 481–490 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

Attempts to rationalise the geological environment of nickel sulphide deposits associated with Archaean ultrabasic rocks has produced much speculation as to the origin of the sulphides and the relative importance of geochemical, mineralogical, textural and structural characteristics of the host rocks. From an economic viewpoint the object of such work is to establish geological criteria which can be used as an exploration guide. Exploration procedure for nickel sulphide mineralisation of the 'Kambalda type' (Hudson, 1972), which occurs at or near the basal contact of Archaean ultramafic flow units and lenses consisted of geological mapping, surface prospecting with soil sampling and rock geochemistry.

Jan 1, 1987

By J Addai-Mensah, W Skinner, K Quast

The efficiency of any iron ore value-adding operation is closely associated with detailed knowledge of the mineralogy, especially in the processing of lower grade and complex ores. There are a number of physico-chemical properties of iron oxide mineral phases (eg goethite, hematite and magnetite) that can be prudently exploited to enhance their processing efficiency. Recent iron ore studies on the upgrading of high-goethite iron ores have highlighted that the knowledge of the various phases of both iron oxide and gangue minerals is critical to the economic processing of these ores. Appropriate knowledge of this kind can lead to better-designed flow sheets for economically viable production of saleable products. With the increasing use of goethitic materials as blend components of iron ore concentrates for steelmaking, this review paper focuses on relevant beneficiation processes and the pivotal role of mineralogy and petrology in producing saleable iron oxide concentrates from ore blends. For goethites, mineral impurities including silica, phosphorus and alumina are very important. Physical separations, as well as those incorporating higher temperatures, have also been included in this review as potential processes to upgrade high-goethite ores.CITATION:Quast, K, Addai-Mensah, J and W, Skinner, 2017. The importance of mineralogy and petrology on the beneficiation of iron oxide ores, primarily those containing goethite, in Proceedings Iron Ore 2017, pp 233–240 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

Good morning and thanks for the chance to talk to you. It's really pleasing to see so many industry representatives here I want to spend a few minutes talking about issues relating to your industry. At the end of today I would like to leave you with three strong messages from government. The first is that this government supports environmentally responsible mining and the endeavours of the mining industry. The second is that explorers and developers are wanted and welcomed in New Zealand. And the last is that it is up to the industry to keep the public properly informed about how your industry and to constantly work on improving your public image. The mining industry is a high-tech industry which fits snugly with our concept of a growing knowledge-based economy. It has particular value for regional development, the gold mining industry alone provides more than 4,000 jobs û mostly outside of the main cities. The industrial minerals industry is twice as large as that. As well as those people directly employed by the industry there are greater downstream effects for the community. One example from the broader extraction industry of this is of the local pie shop down the road from one of Taranaki's petroleum industry locations. The shop sells over $4,000 worth of pies a week to workers in the industry. That's just one example of the positive benefits the industry brings to its local community and is the sort of real positive benefit you need to be telling people about  

Jan 1, 2000

By M Gabbitus, B Young, T Lukins, M Slater

This paper details the implementation of a new type of grade control system at the Black Star open cut mine in Mount Isa, Queensland. It explores the site requirements for grade control, what as previously in place and what the site required moving forward. It also details some of the features of the system installed and why it was chosen over other grade control systems available. Black Star open cut mine has been in operation since late 2004, and was developed to extract the surface extents of the Ag-Pb-Zn mineralisation previously mined in the Isa Lead Mine. Black Star is currently mining seven distinct orebodies in and around active void hazard zones and hence, its grade control requirements are very detailed and complex. The implementation of a new system to manage the model update and block out processes was, therefore, of critical importance to the site and required a detailed understanding of the requirements of the entire mining team from drilling through to geology, survey and production. Having previously run the grade control process using site specific æblack boxÆ scripts and macros, Black Star needed to implement a more open, auditable and flexible system, which allowed the geologists to control the process and make strategic changes as the situation demanded. MineSightÆs Axis Grade Control, with its flexible, generic framework for managing the process, met these demands. Being an out of the box solution that requires minimal setup and training was also a key factor in the decision to use it.CITATION:Lukins, T, Slater, M, Gabbitus, M and Young, B, 2012. The introduction of axis at Black Star Open Cut, in Proceedings Eighth Open Pit OperatorsÆ Conference , pp 71-74 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 18, 2012

By A Boucher, M Baudin, P Androszczuk, I Minniakhmetov, A Rigby, P Machado, M Wright, B Van Dijken

IGO Ltd’s (IGO’s) Nova Operation (Nova), which is 160 km east-north-east of the town of Norseman in Western Australia (WA), mines and processes nickel-copper-cobalt (Ni-Cu-Co) sulfide ore from the magmatic Nova-Bollinger Deposit (Nova-Bollinger), which is hosted by the Mesoproterozoic age high-grade metamorphic rocks of the Albany Fraser Orogen. Over its 56-month life-of-mine (LOM) operations to 31 December 2020, Nova has processed 5.63 Mt of ore grading 2.04 per cent Ni, 0.86 per cent Cu and 0.07 per cent Co from its underground mine. At the end of 2020, both the Nova-Bollinger JORC Code reportable Mineral Resource estimate (MRE) and Ore Reserve estimate (ORE) were >90 per cent classified in the highest JORC Code confidence categories of Measured Mineral Resource and Proved Ore Reserve respectively. The high JORC Code classification confidences assigned to the Nova-Bollinger MRE and ORE results from the 386 km of surface and underground diamond drill testing of the deposit to a nominal 12.5 by 12.5 m pierce point spacing in mineralisation. The close spaced high-quality drilling and bulk mining method employed at Nova has effectively removed the need for any grade control modelling outside of the MRE process. Importantly, having only the one fully drilled out deposit being mined and only the one process plant, Nova’s reconciliation process is in the fortunate situation of not being confounded by issues such as external ore sources and constant updates as new grade control information becomes available. IGO’s Nova reconciliation processes are focused on reconciliation ratios that quantify operational period differences between the MRE and ORE head grade and tonnage forecasts and the process plant head actuals. These metrics have been used to identify key reconciliation issues and have initiated several studies into the causes for specific reconciliation results, which are discussed in the paper. In late 2020, a period of sustained poor reconciliation results led to the recognition that increasing the understanding of risk between the MRE and ORE should be investigated. To assist with modelling stope level risk within the mine plan and subsequent reconciliation, an attempt was made to develop a formula to quantify ‘stope risk’ from MRE metrics such as sample spacing, kriging efficiency and so on

Mar 22, 2022

Sampling of CIL/CIP circuits is typically done by compositing samples of feed and tails over eight or 12 hour periods. As the residence time in the leaching tankage may be approximately 20 hours, the tails from any period being derived from material entering the circuit 20 hours earlier do not correspond to the head from the same sampling period. Moreover, mixing in the series of tanks in a circuit also modifies correspondence between input and output. A special purpose simulator has therefore been developed to allow for the mixing and delay in the tankage and permit estimation of the head assays corresponding to any tailings sample. Thus more accurate assessment of the day-to-day recoveries of gold and silver follows. The model, programmed in Excel, assumes that the tanks are perfect mixers. By inputting the sequential head grades and considering that no leaching has occurred, the head grade which corresponded to the tailings for each period could be estimated. Allowance is made for variations in feed rate over the sampling period by computing the average flow rate of slurry and thus the residence time of each increment of the tailings. This simple model and its application have been found to be subject to some limitations, which are discussed in the paper, resulting in some unresolved variability in results. However, for a typical circuit even the simple model was able to greatly improve consistency of recovery data with variations being approximately halved by eliminating much of the anomalous variation arising from the lack of correspondence between head and tail when changes in head grade are occurring. Therefore, this permits genuine variations in metallurgy to be identified with greater confidence and thus operational shortcomings can be identified and addressed more quickly.

Jan 1, 2006

By Morsky P, Kalapudas R, Natunen H, Virtanen M

The development of autogenous grinding modification in Outokumpu, known with the name 'Outogenius Comminution', was 'reversed'. At first the metallurgists studied and tested tens of years autogenous grinding in detail in full scale circuits at the concentrators of the company. After the final solution already had been found, also a pilot plant was built and now finally, research work is under way to develop a special laboratory method for testing the suitability of ores for 'Outogenius Comminution'.

Jan 1, 1993

By H Kurth

Mining geologists utilise many technologies to map, sample, measure, model and plan before and during the mining process. Predicted ore quality rarely corresponds with feed quality determined by process operators. Objectively measuring conveyed material quality accurately in real time avoids disagreements over mined ore quality and generates opportunities to improve mill feed quality.This paper discusses the well proven PGNAA (prompt gamma neutron activation analysis) technology used in the GEOSCAN-M elemental analyser that is ideally suited to measuring composition of primary crushed conveyed material in real time. Representative, continuous, fully penetrative measurements are unaffected by particle size, belt speed, mineralogy, dust or layering on the conveyor. Material can be directed to processes or stockpiles by utilising measurement increments of typically one to five minutes and then activating diverters to direct increments to the correct location. Waste, low-grade or deleterious material can be rejected to waste dumps or stockpiled for later processing. Material meeting a product specification can bypass unnecessary processing. Paybacks in weeks have been achieved for such applications. Process operators are able to control the blend of ores fed into the mill to improve processing performance and use measurements for ore reconciliation and metal accounting. Utilising the technology to upgrade ore quality after mining and before processing is beneficial in improving plant economics.The technology has been successfully utilised in base metals, ferrous metals and industrial minerals. Mining geologists can determine ore quality being produced in real time and modify the ore quality prior to milling. Ore feed quality measurements are also used by process operators in optimising plant performance. The elemental content can help identify geometallurgical domains as well as other major changes in quality, which may affect processing. This paper outlines proven applications and case studies and proposes some innovative applications.CITATION:Kurth, H, 2017. Measuring ore quality using real-time on-belt elemental analysis – more than grade control, in Proceedings Tenth International Mining Geology Conference 2017, pp 213–220 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

The modern resource extraction enterprise is a complex capital intensive business operating in a world of constantly evolving social, environmental and economic scrutiny. Investors, government, media and special interest groups expect to see business environmental and social performance respond and deliver increasing corporate responsibility and sustainability.   Thorough interrogation of business performance using a multi-disciplinary due diligence approach presents a more sophisticated review and benefits beyond the traditional compliance/conformance 'audit' style assessment.   Using a due diligence approach allows assessment through a comprehensive lens which examines potential short- and long-term risks including sometimes less tangible environmental and social liabilities, and informs management, investors and regulators of broader business performance. This approach provides information in a form that business can measure performance in a repeatable and enterprise wide sense.   This paper provides an outline of the due diligence process applied in this way, drawing from lessons learnt and industry based experiences in the due diligence process and the benefits and tools that can  be applied in an environmental and social due diligence business performance assessment

Jun 1, 2010

The increased cost of imported oil fuels, coupled with our understandable reluctance to commit ourselves to the use of nuclear energy, has resulted in a renewed reliance on coal as a primary source of energy. New Zealand is fortunate in being fairly well endowed in its coal resources, but their exploitation until now, has been on a relatively small scale. Future exploitation, whether from underground or open cast mines, must be on a very much larger scale. This paper outlines some of the factors which should be considered in planning large open cast mines.

Jan 1, 1976

By C C. Souza, S C. Amarante, A C. Arauj

All major companies now producing iron ore in Brazil currently employ or are planning to employ some sort of concentration method to upgrade their fine sized products (sinter feed fines and pellet feed fines). The criteria for the selection of the most suitable concentration method for each application include a series of parameters; the most important among them being related to ore mineralogy. This paper reviews the concentration operations currently employed in Brazil and shows how ore mineralogy plays a fundamental role in the selection of a given method. Examples involving gravity concentration (jigs and spirals), magnetic separation (Rare Earth wet drums, ferrous wheel, and Jones type magnetic separators) and flotation (especially column flotation) are discussed. Fundamentally important for the selection of a concentration method is the mineralogy of iron-bearing minerals and gangue minerals presented to the feed to the concentration unit operation. For instance, the presence of liberated quartz as the major gangue mineral for a pellet feed size stream generally indicates that flotation will be the best selection for the concentration of that stream. However, even if magnetite is present only in the form of crystal relicts within hematite grains, it may lead to the selection of either magnetic separation alone or a combination of magnetic separation and flotation for concentrating such material. Presence of gibbsite and/or kaolinite as the major phase containing alumina will also affect the selection of the concentration method in all cases. Again for the case of pellet feed size streams, kaolinite does not interfere with flotation whereas gibbsite tends to contaminate flotation concentrate (pellet feed fines) as it is depressed together with iron oxides and hydroxides during the reverse cationic flotation process.

Jan 1, 2002

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 J Levett, O Rondon, I Glacken

Reporting Codes are not prescriptive on methodologies to report or classify Mineral Resource Estimation results, but the assessment of risk and uncertainty is required, and is likely to be increasingly important in future Code updates. The 2012 JORC Code indicates that relative confidence in tonnage-grade estimations should be considered for classification, and that there should be a discussion of relative accuracy and confidence levels in the Mineral Resource Estimate. These considerations are also relevant to the drill hole spacing required for various classification categories, along with other geological and data quality criteria. This paper summarises the theory, principles and current practice of various drill hole spacing analysis techniques for both achieving a desired level of resource categorisation and for optimising grade control or resource drill-out costs. The authors provide practitioners with a guide in their use to assess uncertainty and relative accuracy, as illustrated by a number of case studies. While all drill hole spacing studies rely on the assumption of consistency of the continuity model from current to future drilling, the range of methods available provide much more objective outcomes than previously adopted ‘rules-of-thumb’.

May 24, 2023

By J Lea, P Hatherly, J L. Edwards

Coal exploration has traditionally involved the acquisition of data to enable a resource to be quantified and qualified to the extent that its economic potential can be determined. This process commonly relied on: drilling to determine the depth and thickness of coal seams, broad characterisation of the overburden and interburden, and to provide cores for coal quality analyses; basic wireline logging to cross-check the depth and thickness of coal seams and provide some indication of rock mass strength; and basic surface geophysics and remote sensing to identify major geological structures. In recent years, the adoption of the JORC Code as a basis for the reporting of resources and reserves has placed a greater emphasis on the need for detailed, reproducible data sets that not only satisfy the traditional requirements of mine planners, but also satisfy the governance requirements of corporate and financial institutions. Similarly, the development of sophisticated numerical modelling techniques for use in both open cut and underground mine design, has seen a greater demand for precise geotechnical data, in situ stress characterisation and hydrological information as routine input to the design process. These requirements, coupled with the prevailing trend toward high capital, relatively inflexible mining techniques less tolerant of geological surprises, and the need for consideration of environmental issues such as groundwater impacts and surface subsidence, requires that modern exploration programs be multifaceted, and designed to commence capturing data relevant to ædownstream issuesÆ even during the initial phases of exploration planning.

Jan 1, 2009

By T J. Callaghan

The Avebury nickel mine in Western Tasmania is a disseminated nickel sulfide deposit hosted in intensely metasomatised Cambrian ultramafic resulting from later Devonian granite related hydrothermal activity.Variable metasomatism of the ultramafic has formed two distinct gangue mineral assemblages. Less metasomatised ultramafic is comprised of fine grained black antigorite with minor disseminated chromite, magnetite and pentlandite. Intensely metasomatised ultramafic is altered to a pale grey or green, coarsely crystalline tremolite/actinolite and diopside assemblage with minor magnetite, chromite and sulfides. Both gangue mineral assemblages are frequently intermixed in ore grade mineralisation.The bimodal gangue of either serpentinite or metasomatised ultramafic presents challenges to drilling, mining, resource estimation and mineral processing as they possess very different physical properties. Mineralised serpentinite has a mean bulk density of 2.8 g/cc and the ultramafic skarn a mean bulk density of 3.2 g/cc. Physically, the ultramafic skarn is hard to break percussively creating difficulties in the crushing circuit and reducing mine development rates. However, it is non-abrasive and grinds readily, resulting in increased diamond drilling rates and increased mill throughput. Conversely the serpentinite gangue is softer and breaks easily resulting in accelerated development rates and crushing circuit throughput. However, its fibrous nature reduces grinding efficiency, increasing bond work indices and reducing diamond drilling rates.Predicting the ratio of serpentinised to metasomatised ultramafic is possible through use of the resource blockmodel, assisting mine scheduling, predicting mill throughput rates, energy consumption and grade control drilling rates.CITATION:Callaghan, T J, 2017. Challenges of bi-modal gangue mineralogy in mining geology, in Proceedings Tenth International Mining Geology Conference 2017, pp 23–26 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By A Clark

When production targets are not being reached it is essential to determine what the operating problems are so that remedial action can be taken. It is also imperative that all persons who are part of the production stream within a mining operation know and understand what the operating difficulties and delays are so that corrective action is effective. This includes the supervisors, superintendents, planning team members and managers. A new approach recently adopted at Hilton Mine to help identify these operating difficulties has been to use short-term schedules and reports known as the Daily Shift Schedule Controls (DSSC), and the Daily Weekly Operating Reports (DWOR) respectively. These control elements have enabled management and supervisory staff to accurately identify labour inefficiencies and ultimately determine capital resources.

Jan 1, 1998

By J Howard

Following discovery in October 2004, commencement of development in February 2007 and first ore production in mid 2007, the Trident gold deposit, located in the Eastern Goldfields of Western Australia, has now been successfully mined for over three years. Three years of operational history has enabled the performance of the Trident underground mine to be reconciled against the mine plan and strategy proposed for the original feasibility study.The Trident deposit, initially based on two lode systems known as the Eastern Zone and Western Zone, has been continuously drilled, interpreted and re-interpreted over the period and as a result the addition of the Athena, Apollo and Artemis lode systems as well as numerous smaller scale lodes has been realised. The first three years has seen the Trident underground mine quickly move up to its 1 Mtpa design production rate. The mine plan and strategy used in the initial feasibility study and subsequently implemented, required sufficient flexibility to enable modification and optimisation to mine plans as ore zones were further defined. The ability to modify the mining plans has enabled Avoca to achieve its mining targets at Trident. With over 250 000 ounces gold produced to January 2010, the company is well positioned to achieve its ten year vision associated with the Higginsville Gold Project.This paper offers an account of operational experiences whilst providing comparison to assumptions and methodologies used in the original feasibility study. The paper is a sequel to a paper presented at the Tenth Underground Operators’ Conference held in Launceston, Tasmania titled Development Strategy of the Trident Underground Gold Mine.

Mar 21, 2011

By C Armstrong, B Wentzinger

Upstream embankment raises often represent the lowest cost option for increasing the capacity of tailings storage facilities (TSF), but also pose the highest stability risk due to constructing on top of previously deposited tailings.This paper presents an overview of key aspects in the geotechnical investigation and design of upstream raises and some recent lessons learnt from experience across a number of TSFs in Australia. A summary of recommended field investigation and laboratory testing methods is provided with a focus on collecting quality information for design purposes. A strong focus is given in developing an accurate assessment of pore water pressures, which, if not correctly understood can have disastrous consequences on tailings strength parameter interpretation and wall stability assessment in static and post-seismic conditions.The assessment of the contractive or dilative shearing behaviour of the tailings material and rigorous interpretation of design characteristic values are presented. Some comments on stability analysis options and proposed methodology are also provided.CITATION:Wentzinger, B and Armstrong, C, 2018. Lessons learnt in geotechnical investigation and stability analysis for upstream tailings storage facility raise design, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 333–348 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018