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By M Fahey, A B. Fourie

Over the past ten years, the mining industry has witnessed the introduction of a new and innovative mine filling technique known as paste fill, which consists of placing full stream tailings with small amounts of binder and water into underground stopes. Paste fill has benefits over traditional backfill methods, such as higher solids contents than hydraulic fill and easier transportation than rock fill. From a geotechnical perspective, the behaviour of very fine material in a fully saturated state can be complex, particularly when binder is added. Previously, there has been no rigorous solution to understanding the paste fill deposition process, resulting in uncertainty regarding critical aspects such as barricade load calculations. This uncertainty has the obvious consequences of potential barricade failures (including at least 12 over the past four years), and for many operations attempts to deal with this uncertainty has led to excessively conservative filling schedules, restricting production. This paper presents an application of Minefill-2D, the first rigorous model capable of representing the paste fill deposition process. The model couples the processes of material accretion, consolidation and cement hydration to calculate the distribution of stress around a stope (including the total stress applied to barricade structures) during filling. Minefill-2D is a finite element numerical program, which has been verified using laboratory element tests, centrifuge tests and in situ measurements (Helinski, 2008). The authors present a sensitivity analysis, carried out using the model, to demonstrate some of the critical and less critical aspects relating to paste backfill deposition. The results of this sensitivity analysis are used to devise a fill management strategy that can be utilised to minimise the risk of barricade failures and maximise fill rates where appropriate.

Jan 1, 2008

The Mt. Sisa Orebody on Misima Island, P.N.G., consists of gold-silver mineralization associated with massive carbonate and amor- phous iron-manganese oxides in fractures and breccia matrix. The orebody forms the north- ern extension of the Umuna deposit. The mineralization lies within the three kilometre strike length of a northwest trending, 300 metre wide, high angle fault zone. The fault zone structure is deeply oxidi- sed, with the manganiferous oxide material resulting from oxidation of carbonate. The wallrocks are metamorphosed basement psammopelites and basic volcanic rocks, exten- sively intruded by microgranodiorite. These are dominantly epidotized and sericitized. The precious metals are associated with anomalous Cu, Zn, Pb, Mn, As, Ba, Ga, Sb, and. Mo. Many of the features of the Mt.Sisa mineralization are characteristic of volcanic- hosted epithermal deposits of western North' America. Lithologic and textural gradation is ob- served between the carbonate hydrothermal breccia-fill at Mt. Sisa, and the quartz domi- nated dilational fracture-fill mineralization which forms most of the Umuna deposit to the south. This gradational relationship is ana- logous to that within the Amethyst-OH vein system at Creede, Colorado, where it is shown to be indicative of deposition from laterally migrating fluids.

Jan 1, 1987

The investigations of the Leningrad ruining lilstitute on this problem are carrying out in the following main directions: 1) The analysis and study of contaminants migration at particular sites of mining development; 2) The working out of theoretical and me- thodical basic principles of aquifers migration tests; 3) The work- ing out of methods of the forcasting of groundwater pollution pro- cesses; 4) The theoretical and uethodical substantiation of hydro- geological observations of groundwater pollution processes; 5) The wort ing out of the measures at the groundwater control and their rational use at the particular sites of mining development. The research that have been carried out by the present moment have covered the wide range of wining and geological conditions -- as from the point of view of specific genetic types of water-be- aring rocks (porous, fissured and fissured-porous), as well as from the point of view of pollution sources (surface waste water basins and underground basins of non-standard water) and the cha- racter of the latter's migration (tracers, physically neutral ef- fluents, heavy or light ones). The combination of specialized mi- gration tests and observations carryed out at uoayi, sites, as well as the following ar~,alysis o:i the data of field study allowed to get useful theoretical, methodical and practical results on the all directions above mentioned, ns the summing up of these results the author proposed the concept of controlled ground :ester polluti on. This conception is based on three whales" - groundwater self- purification, engineering prevention measures and ground-water monitoring correlated with each other by succes i.vely refined (ac- cording to the observation data) hydrogeologicZl forecasts.

Jan 1, 1988

By G Mudd, N Haque, S A. Northey

Life cycle assessment (LCA) provides an internationally standardised framework for estimating the environmental impacts associated with products or services (International Organisation for Standardisation, 2006). A particular strength of LCA is the ability to consider indirect impacts that occur at different stages of a product’s life (eg raw material acquisition, manufacture, use, disposal or recycling) and through its supply chain (Figure 1). A wide variety of impact categories are able to be considered by LCA, such as the potential contribution to global warming, ozone depletion, marine eco-toxicity or freshwater eutrophication.CSIRO has a long history of using LCA to compare the environmental impacts associated with alternative mining, mineral processing and metal production technologies (Haque and Norgate, 2014; Norgate and Haque, 2012, 2013). These ‘mine-to-metal’ assessments have primarily focused upon estimating embodied energy and greenhouse gas impacts associated with these production processes; however, more recently there has been a refocus to also consider consumptive water-use impacts in more detail (Northey et al, 2014).CITATION:Northey, S A, Haque, N and Mudd, G, 2016. Water-related data requirements for improved life cycle assessment of mining, mineral processing and tailings management, in Proceedings Life-of-Mine 2016 Conference, pp 16–18 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

It is a well known fact that the best method of rock reinforcement is to avoid physical ground support. This goal can be achieved by means of: - Increasing the rock structural strength - Geological definition and forecasting. - Sequencing the excavation - Smooth blasting In many cases however, extra ground support is needed in order to maintain safe working conditions. In an open pit, the structural strength of rock cannot be increased by lowering the pit walls due to economical reasons. Economy demands steeper walls and less waste to be hauled to the dump. The geological conditions can also often be extremely poor and unpredictable. For excavation sequencing and smooth blasting there are good possi- bilities, such as cleaning of the pit walls after the main excavation, arul- ing of long small diameter straight inclined holes, use of smooth blasting techniques and lightened explosives.

Jan 1, 1989

Before I begin this paper, I thought that it would be important to start with a brief background on myself. This will give some insight into where I am coming from with some of the ideas presented in the body of the paper. I studied mining engineering at the University of New South Wales, graduating with Honours in 1999. When I finished university I was offered a job with PricewaterhouseCoopers in Sydney, working in the Energy and Mining Group of the Audit practice; which I accepted. I have been working at PricewaterhouseCoopers now since January 1999, completing an accounting conversion course at the University of Technology Sydney along the way. I am currently beginning my Professional Year for Chartered Accountant qualification. During my later years at university, continuing on through the start of my working career, I have been involved with the Sydney Branch of The AusIMM; firstly, as a student representative and, now, as the Young Professional Representative. Therefore, you can probably see that I will have very different young professional experiences than some of my peers who have been working on mining sites. The purpose of this paper is to examine the challenges that face graduates who are entering the industry and what solutions are used to ensure that this entrance is as smooth as possible. A challenge has then been made to the industry and The Institute in the form of further observations on ways that this entrance may be improved and the development of graduates to be more effective. In preparing this paper I have discussed various graduate experiences with some of my colleagues in order to see what some of the challenges they, themselves, face now and, also, going forward. I also discussed with them what they see as solutions to these challenges, drawing on some of my own experiences in a different company environment.

Jan 1, 2000

By J E. Everett

Maximising ore tonnage at a selected target grade requires that appropriate ore identification criteria be established. Iron ore mining block models may consist of many millions of estimated blocks, each block corresponding to the selective mining unit (SMU), with grade interpolated from drill hole data. Each block can be considered as a potential ore candidate. Analysis of such a huge database can require large computational resources, especially for sensitivity analysis requiring multiple computations. However, an alternative streamlined approach is possible, where the data are compressed to an appropriately smaller and representative subset. The consequent data reduction not only makes it feasible to consider the simultaneous analysis of multiple pits but also considerably speeds up computation, enabling sensitivity analysis of the potential ore tonnage as a function of the required grade. Ore identification criteria can be successfully established using appropriately chosen reduced data comprising less than one per cent of the blocks. The ore identified is virtually indistinguishable in tonnage and grade from the ore that would be selected using the entire block model.Two methods of data reduction are tested: sampling (using a proportion of unaltered blocks) and binning (consolidating groups of blocks to a single average grade). The source blocks are first sorted (such as by location, analyte grade, principal component score, random order or value) before sampling or binning. In this study, the sorting options considered were by location and Fe grade. The effectiveness of each method was evaluated using the block model subsets to select the maximum tonnage of ore at a specified target grade. Block model data from an anonymous Pilbara iron ore project with about one million blocks averaging 1.132 kt were used. The blocks are from multiple resource models, to be blended to a single product. Sampling is shown to be superior to binning because sampling preserves the full variability while binning, although matching the mean block grades reduces their variability.It was found that the appropriately sampled data sets (sorted by location) gave results virtually identical to the results for the full data set, even when the samples comprised less than one per cent of the original blocks. The reduction in computer time to identify maximum tonnage at a specified grade was approximately proportional to the sample percentage. The increase in computation speed greatly facilitated sensitivity analysis. A sampled data set of one-eighth the total block model was used to investigate the effects of changing each of the component grades around the original grade specification. The results of this sensitivity analysis are discussed, and illustrate the potential benefit of carrying out sensitivity analysis in determining feasible and marketable product grades.CITATION:Everett, J E, 2015. Block model data reduction and sensitivity analysis, in Proceedings Iron Ore 2015, pp 263–270 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

Interrelated data for five fundamental features of production processes would help promote the- development of the discipline and profession of extractive metallurgy. The features are the input materials, the products, equilibria, kinetics" and movement of materials within the reactor. Aspects of overall process performance that could be developed in these terms include quantitative comparison of reactor engineering options, process dynamics, interruptions to operations, and recycling. The ability to be able to forecast these and other aspects of process performance would be valued by most metallurgists. Although data have been reported for each of these aspects they have been more relevant to process economics than process fundamentals. The data have not often been interrelated via the fundamental features for a particular raw material-process system; nor have ~ similar data been related for different systems.

Jan 1, 1986

By Reichman J, Chapman G

The features of seam gas drainage from the point of view of mathematical modelling are outlined and discussed: 1. The use of conventional single phase gas reservoir simulator for very simplified modelling. 2 Alteration of a conventional petroleum reservoir simulator into a specialised simulator for seam gas drainage. 3. Application. of a conventional petroleum reservoir simulator for modelling of seam gas drainage by the way of pseudo-functions and sacrifying one dimension.

Jan 1, 1982

By Chavant G, Begis D, Gunther J

To study the ventilation of a mine (improve on the existing situation, examine extension projects) the calculation program used must take into account all the resistance values in the branches of the network. These resistance values are generally determined by measurements, which are accurate to a greater or lesser extent. In order to arrive by calculation at the flowrates measured :n the mine at a given moment, the resistance values have tto be adjusted experimentally. This manual operation is lengthy and delicate.

Jan 1, 1988

WMC Limited, owner/operator of Olympic Dam, the worldÆs largest underground uranium mine and the fourth largest underground copper mine has now completed an expansion that has been classed as a benchmark in the mining industry. To achieve a production increase from 3.4 to 9.25 Mtpa from an underground mining operation in two years was a major challenge, it was essential to review the overall materials handling system from æthe face to the stockpileÆ. The challenge was two-fold:How to deliver 30 000 tonne of ore per day to the processing plant, from a single underground mine? To provide the processing plant with a consistent metallurgical feed. This paper traces the transformation from the old to the new materials handling system at Olympic Dam.

Jan 1, 2000

By R Barrette, V Lawson

Over the last year at Clarabelle Mill, three circuit reconfigurations were implemented. One circuit reconfiguration, æA CleaningÆ, was initiated due to a furnace failure at the smelter complex, and two of the circuit reconfigurations, æincreased copper (Cu) separationÆ and the æInterim IsaMillÖ circuitÆ, were seen as opportunities to increase cash flow through the mill. A Cleaning and the Interim IsaMillÖ circuit took advantage of engineering design already completed for a major capital project. The engineering for each was modified, as needed, and construction of the required portions of the capital project was fast tracked. The increased Cu separation circuit change used existing test and plant equipment to increase the plant Cu concentrate production. Implementation of the projects required teams that included operations, maintenance, technical support, project management and capital project resources. This paper discusses the business reasons driving the changes and the forethought or synergies with other work, which made them a success, and what was learned through each project. CITATION:Taylor, A, Lawson, V and Barrette, R, 2012. Responding to the challenge - Necessity driving circuit change, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 247-254 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

At the beginning of the seventies pre- drainage of methane was introduced in West German coal mining in order to reduce the gas emission from the worked seam. After three pilot tests on the "Rheinland" Colliery (86 boreholes in seam "Prasident"), "Bergmannsgluck/ Westerholt" Colliery (23 boreholes in seam "Gustav") and "General Blumenthal" Colliery (27 boreholes in seam "Hugo" and 170 boreholes in seam "Karl") systematic large scale tests with extended investigations were carried out un the "Rheinland" Colliery (127 boreholes in the seams "Anna", "Blucher", Prasident"). During this time an analogous test was carried out on the "Consolidation" Colliery (21 bore- holes in seam "B"). In these studies and tests the technical feasibility, efficiency and economy could be proved, so that pre-drainage of methane starts spreading. On the "Rheinland" Colliery pre-drainage has become common practice in gassy seams. Mainly two points impede a faster spreading of method: 1. in many cases the necessary requirement, that one or both of the gate roads should ire driven 6 to 12 months before the face is worked, is missing. This is mainly due to the difficulty of retreat mining in passe seams.

Jan 1, 1982

My topic for today is the Crown Minerals of the future. New work initiatives are underway and the organisational structure is being overhauled. These are not insignificant changes and in this paper briefly summarises these proposals. These new work initiatives and changes to the organisational structure will have implications for the industry as a whole and also for the way individual clients interact with Crown Minerals.

Jan 1, 2003

By J Beniscelli

Some words to honour Pedro:Pedro was among the few persons with a very high level in geology modelling, resource and reserve estimation, geometallurgy development, sampling theory applications and a deep understanding of the mining industry needs. He had brilliant ideas about new developments on economic geology. He was always looking at the long-term and proposed challenging questions a decade in advance on their solution.The fundamental aim of geometallurgy is to add economic value to the mining of mine resources by timely providing information and knowledge about the relevant metallurgical variables represented by their space models. In this manner, geometallurgy allows obtaining the optimal design of a project, mitigating processing risks, optimising and supporting production plans and identifying and assessing mining business opportunities.This paper describes the conceptual framework and geometallurgical definitions and some of Codelco’s experience during the last 15 years.

Sep 5, 2011

Australia is a highly significant hub in the global minerals business. This paper will present the results of global and national studies looking at the potential 20 to 30 year future evolution of the mining and metals industry.   Globally, the World Economic Forum launched a Mining and Metals Scenarios project in January 2009 to explore the question: 'How will the environment for the global mining and metals industry look in 2030?'. As part of a structured strategic foresight process, eight workshops were held across the world over the course of a year which brought together over 200 leaders from the private sector, government, academia and non-governmental organisations. The workshops were supplemented by personal interviews and guided by an international advisory board.   Critical uncertainties for the future of the industry were identified and compare extremely well with the outcomes of a national survey of AusIMM members identifying the key issues and drivers shaping the future of their operations. Global context was one of the most significant issues identified by The AusIMM membership, which is expanded in the World Economic Forum study in terms of: geopolitics; global governance; action on climate change; and economic outlook. More specifically, this global study developed three divergent yet plausible scenarios describing potential environments for the global metals and mining industry in 2030. These scenarios are compared with ground-breaking global foresight work coordinated by the Stockholm Environment Institute in the 1990s. The scenarios will help decision makers rehearse alternative futures, anticipate potential hazards and identify business opportunities - new solutions, new markets and new connections. The presentation will present these scenarios as a way of challenging thinking, testing established wisdom, and stimulating imagination about the business case for the mine of the future. As Marcel Proust put it, 'The real voyage of discovery consists not in seeking new landscapes but in having new eyes'. This is an ABSTRACT ONLY no paper was prepared for this presentation.

Jun 1, 2010

By J P. Richards, M D. Johnston

The Porgera gold mine, located in the highlands of Papua New Guinea, produced 7.7 Moz of gold between 1990 and 1998. Reserves are estimated to be 12 Moz of Au. The deposit is associated with 6 Ma-old mafic alkalic intrusions emplaced at shallow levels into unconsolidated Jurassic and Cretaceous sediments, where they caused the formation of peperites. The mineralisation consists of an earlier base-metal-sulphide-rich stage with sericite-carbonate alteration (stage I), and a later phase represented by quartz-roscoelite veins (stage II). New styles of mineralisation and alteration have been recognised at depth in association with stage I. They consist of the assemblages magnetite-chalcopyrite-pyrrhotite and biotite-actinolite-anhydrite respectively. In addition, the recent recognition of adularia in some stage II veins (with roscoelite) confirms the similarity of this style of mineralisation with other adularia-sericite or low-sulphidation epithermal deposits.

Jan 1, 1999

Coal mining ceased at Strongman Mine this year after 70 years of production. Underground mining finished in 2003 and opencast methods began in 1998. During the life of the mine, 8 million tonnes of coal was extracted from two underground mines and 1.2 million tonnes removed through opencast methods. Strongman Mine is within the Grey Coal Fields; various seams have been extracted from the Rewanui Coal Measures. Coal extracted was predominantly of thermal or semi-soft specifications and characterised by low sulphur and low ash.   The area has steep topography, high rainfall (>3000 mm/yr) and is particularly exposed to westerly quarter winds. Strongman 1 and 2 underground mines are located in the steep, narrow valley which leads to the Strongman Opencast at the top of the valley. Subsidence from underground mining combined with spontaneous combustion, has resulted in an underground fire which has had substantial surface effects. Opencast mining in the steep topography resulted in several landslides at the perimeters of the site. These factors, along with water management, topsoil management and erosion control have added to the complexity of rehabilitating the site.   Rehabilitation of the site is well underway, including infrastructure removal, final landform creation and revegetation of the Strongman Opencast footprint (~45 hectares). Some innovative methods of rehabilitation have been trialled. Successful trials such as helicopter-seeding and moss hydro-seeding on highwalls are now routinely used along with traditional revegetation practices. 18 hectares disturbed land has been replanted with 88 000 seedlings, and another 200 000 seedlings are scheduled for planting over the three years. Fire management is an ongoing challenge; however thermal photography shows a steady decrease in hot areas which have been contained by grout curtains.   Mine closure is some time away and will occur after all standards set by Solid Energy and regulatory bodies are achieved.

Jan 1, 2006

By L Xiong, W J Shi, J H. Wei

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Baizhangzi gold deposit is located in the northern North China Craton. The structural and lithological controls on the location and geometry of orebodies were studied through geologic survey, ore spatial configuration analysis and structural analysis. The orebodies of the deposit comprise auriferous quartz-sulfide veins and disseminated gold-bearing sulfides. The auriferous quartz-sulfide veins are dominantly hosted by the NNE- (and NE- and NW-) trending faults, which are subsidiary structures of the regional NNE-trending F2 fault. The subsidiary NNE-trending faults, having sinistral reverse kinematics, are associated with the sinistral reverse kinematics event of the F2 fault, which happened under a regional S–N-oriented compression stress field. The subsidiary NE- and NW-trending faults appear to be compressive and extensional respectively. These NE- (and NW-) trending faults are restricted to the granite intrusion and are associated with a sinistral strike-slip event of the F2 fault, which reactivated under a NW–SE-oriented compression stress field. It makes significant influence on geological evolution and distribution of different ore types that the strike of the F2 fault presents significant transition from NNE- to NE-trending in vertical. The ore-bearing disseminated host rocks, with widespread silicification and pyritisation, distribute in the lower inner contact zone of the granite intrusion, especially in the lower wavelike boundary of granite intrusion.CITATION:Xiong, L, Wei, J H and Shi, W J, 2015. Structural and lithological controls on the location of orebodies in the Baizhangzi lode gold deposit in western Liaoning Province, China, in Proceedings PACRIM 2015 Congress, pp 193–200 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By Zamora C

The performance of a system for detecting the onset of overloads on rod mills is described. The system has bee,, tested at CODELCO E1 Salvador Concentrator where, due t,, variations on size distribution of the copper ore feed, th' rod mill is frequently subject to overloads. The main inpur signal to the system is the rod mill sound, after being measured and analog conditioned. This signal and othe signals measuring the fresh ore feed and the mill watt addition are fed to a computer containing a simpl mathematical model. The model parameters are empiricall estimated and an analog output signal is generated, whic gives an early prediction of the overload condition. The experimental results described in this paper show that the overload condition may be predicted with an anticipation of about three minutes.

Jan 1, 1985