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By Ken Campbell

Exploration and mining in Third World countries will essentially be an exercise in the transfer of technology. We must not underestimate the effort it will take to develop the necessary industry peer group in these nations which can accept the latest western technology and use it to good effect.

Jan 1, 1994

The undeniable fact of life in the next 25 years will be the increasing difficulty of the physical conditions of Australian orebodies facing future miners. We are all familiar with names such as the 3000 orebody at Mt Isa, Hilton, Century, Macarthur River, Cannington, and Ernest Henry. These projects represent a significant. proportion of the planned underground mine development in Australia. Moreover, many of these new orebodies are an order of magnitude more difficult to mine and process than their predecessors. Extraction will be from deeper and potentially more hazardous working environments. Occupational health and safety considerations will place unprecedented demands upon mine operators and technology providers of the future.

Jan 1, 1994

The paper describes a computer model developed within the State Electricity Commis- sion of Victoria for use in open cut planning. The purpose of the model is to simulate all the typical occurrences in, and influences on, the coal supply and overburden disposal systems in order to be able to assess their performance. The model incorporates much of the long term and day-to-day operations planning logic required for the allocation of resources within an open cut. This logic takes account of power station demands, bunker stocks, plant and crew availability, the balance of reserves between dredgers, planned maintenance, etc. The perfor- mance of plant within the system is simulated using random selections from statistical distri- butions of Time to Failure and Time of Failure for each plant item. The application of the model in selecting a suitable bunker capacity in a notional open cut development is described to illustrate the potential of the model in optimising plant selection.

Jan 1, 1982

By Muller GP, van Deventer JSJ

A mineralogical analysis has shown that in the Hartebeesfontein ore studied, uranium is associated mainly with uraninite, sulphides such as pyrite and to a lesser degree carbonaceous material such as thucolite. Little could be learned from the literature regarding the mechanism of flotation of these uranium-bearing minerals. A wide variety of reagents were used so that conditions enhancing the flotation of either the sulphides, carbonaceous material, oxides like uraninite, or combinations thereof, were created. As could be expected, the xanthate based floats gave-better selective recovery of sulphides than oleic acid. A substantial fraction of the uranium is associated with pyrite, so that addition of oleic acid to a xanthate float did not enhance the recovery or grade of uranium. After a pre-leach with sulphuric acid in which the pH and Eh were controlled so as to destroy the uraninite, higher uranium recoveries were obtained for the combined float (xanthate, DTP and oleic) and the DTP float. This was most evident when iron was added before flotation. Roasting, which destroyed the sulphides and thucolite, caused a significant decrease in uranium recoveries. The uranium liberated in this way was obviously not flotable in the same way as the uranium liberated from uraninite. A small amount of iron (2 kg/t) added before milling resulted in slightly higher grades and recoveries of sulphur for xanthate based floats. Higher iron additions had a detrimental effect on sulphur recoveries. Even in the case of oleic acid the addition of small amounts of iron had a positive effect on the recovery of sulphur and uranium.

Jan 1, 1993

The MIMDAS geophysical data acquisition system developed and tested by the former MIM Exploration Pty Ltd (MIMEX) is now commercially available worldwide through Geophysical Resources and Services Pty Ltd (GRS). The system implements several new features in its design that give it significant advantages over conventional systems and allows for new approaches to electrical exploration. In particular, the achievable signal to noise levels permit exploration to depths once thought beyond the range of electrical exploration. The flexible multi-channel configuration lends itself to truly 3D surveys in the style of modern seismic techniques. Each of these aspects is illustrated with a number of case histories from both Australia and South America.

Jan 1, 2004

By Terrill JE, Fergusson LJ

In the last decade of precious metal exploration, several important gold discoveries have conclusively demonstrated that epithermal gold deposits formed in what were once active geothermal areas. A significant deposit in this category is the Lihir Island discovery in the Tabar-Ferri volcanic island arc off the coast of New Ireland, Papua New Guinea. Within that arc are the Feni Islands where exploration by Esso PNG Inc. and City Resources Ltd. has been carried out since early 1984. On Ambitle Island in the Feni Group, an epithermal gold prospect located within a young caldera has been tested by diamond drilling. The drillholes intersected a boiling zone at depth beneath acid altered 'cap' rocks. The zone is 30-60 metres thick and comprises hydraulically fractured and mineralised lavas with gold grades of 1-7 g/t. The prospect is still an active geothermal area with current boiling in the zone tested. As on Lihir, the recent epithermal alteration and mineralisation overprints a relict prophyry system. On Ambitle and the adjacent Babase Island several other, cooler exciting gold prospects are currently being tested.

Jan 1, 1987

Mine closure is a legitimate element of the mining cycle and like mine development involves technical planning, permitting, and finally construction. Closure begins with the mine's operational footprint and transforms the site so that it meets the explicit requirements of the owners and regulators. Implicitly, the closure will increasingly need to meet the requirements of other interested parties such as the local community, workforce, and future land users. Golden Cross is the first modern mine closure in New Zealand. It operated for 6 + years as a mid-size gold and silver mine winning ore from both underground and open pit sources, and processing via a carbon in leach circuit including a cyanide recovery stage prior to tailings disposal. The mine is situated in a sensitive high rainfall environment, and is complicated by the existence of a large ancient landslide underlying most of the tailings dam and waste rock embankment. The regulatory process for mine closure in New Zealand is not clearly understood by operators or regulators alike. The Golden Cross mine was permitted under the Mining Act 1971 and closed primarily under the Resource Management Act. This switch of legislation, the parallel reorganisation of many government departments, and change in societal expectations with respect to long term environmental stewardship during the life of the mine resulted in the requirements of closure being significantly different to the expectations at permitting.

Jan 1, 1999

By A W. Bewsher, T C. McCu, D B. Mapleson

The Miitel nickel sulfide deposit has been overprinted by a family of late stage structures that have acted as conduits for fluids that have contaminated the orebody with arsenic minerals. This has resulted in highly variable and unpredictable arsenic grades throughout the Miitel orebody. The ore produced from Miitel is processed under a toll-treatment agreement with Western Mining Resources Kambalda Nickel Concentrator. Part of this arrangement includes a financial penalty if monthly average arsenic grades in ore delivered exceed 800 ppm. This constraint has provided an extra challenge to the Miitel mine geologist in addition to daily underground duties. Routine development and stope mapping, close spaced sampling and cross-sectional interpretation were used in building an understanding of the structural controls of arsenic mineralisation and ore repetition at the Miitel nickel mine, and in providing maximum input to mine planning and scheduling. The distribution of structures responsible for arsenic introduction is now well understood from detailed mapping, sampling, and interpretation. By applying these insights to mine scheduling, the operation has successfully managed arsenic levels within the required specifications. Geological mapping has also improved the understanding of the structural complexity of the ore deposit, leading to the addition of ore tonnes and an increased confidence in resource modelling. Regular sampling and tight controls on data quality provided confidence in a strongly skewed arsenic data set. Multiple Indicator Kriging has been used for resource estimation of the arsenic contaminated nickel ore since it allows explicit control of the spatial influence of extreme grades in the positively skewed arsenic sample population. Both the grade control and exploration data sets are used to model the arsenic distribution.

Jan 1, 2003

By M Matheson

Increasingly, owners and operators of underground mines that have a long history are realising the economic and practical advantages of capturing historic mining records and converting hand drafted plans of underground mine workings into an electronic collection of attributed 3D wireframes that can be used for mine planning and exploration purposes. This case study looks at the conversion of historic data to 3D models, with examples from three historic mining operations where this task has been undertaken: West Wits gold projects in South Africa, Northern MiningÆs Radzimowice gold mine in Poland and Avalon ResourcesÆ Viscaria copper mine in Sweden. West Wits Mining Limited holds leases in the West Rand Goldfield of the Witwatersrand Basin, which has significant gold and uranium resources that have been mined since the 1890s. The Radzimowice Gold mine, Poland, hosts Au-Cu-As-Ag mineralisation that has been exploited since the 15th to 16th centuries. The Viscaria Copper mine is located in northern Sweden and was operational during a 15 year mining period to 1997. The process of data collection, management and modelling is inherently challenging for these mines; specifically, collation of historical information, organising this data into logical arrangements that could be validated and sequentially creating 3D models using geo-spatial computer software. Despite the challenges and costs involved in creating a digital 3D model, the conversion has added significant value to each project through identifying areas of potential new resources, aiding planning and presentation to stakeholders. This paper outlines the processes involved in conversion from paper records to a 3D model, the challenges encountered and how these can be overcome, and importantly, the practical and economic advantages of undertaking such a task for explorers, miners and investors.

Jan 1, 2009

By P D. Franzmann, D J. Readett, J Peterse

A better connection between laboratory- and pilot-scale test results, and heap bioleaching performance can be achieved by generating reliable information on the fundamental microbial, chemical and physical processes that occur in heaps and incorporating this information into a comprehensive and robust model. More efficient heap bioleaching, particularly of chalcopyrite, has the potential to add value to the mining industry as well as deliver attractive environmental and social benefits to the communities within which those companies operate.The results of fundamental chemical and microbiological studies of the leaching mechanism, the temperature dependence of chalcopyrite bioleaching, and the optimisation of leaching conditions are described with examples from full-scale heaps. The development and application of a number of novel techniques and tools has assisted our understanding of heap subprocesses mineralogy, hydrology, chemistry and microbiology. The heap bioleaching model HeapSim, which embodies a large number of effects not previously accounted for in other models, continues to be refined and has been applied successfully to the study of several heap bioleach systems.

Jan 1, 2004

The Porgcra gold deposit is an epithermal gold base-metal deposit located in the Enga Province of Papua New Guinea. Gold-silver- spha le rite-galena-pyrite mineralization is related to stocks and dykes of dioritic composition which have intruded a series of folded marine sediments, mainly shales and siltstones, often with calcareous and carbon- aceous horizons, of middle Jurassic to middle Eocene age. The most intensely mineralized zone is at Waruwari Hill, where the mineralization occurs predominantly as massive mixed sulphide veins, and less frequently as quartz-chlorite veins and as disseminations. Mineralization occurs in all rock types and several phases of mineralization have been Recognized.

Jan 1, 1980

Since I first enrolled to study Mining Engineering, the idea of working with big machinery and explosives has always appealed to me. After a few courses at uni, combined with vacation work and a number of presentations at the New LeadersÆ Conferences I had attended, I began to realise that the explosives side seemed to have more appeal than the others. As I look back on the past two and a half years that I have spent with Orica Australia Pty Ltd as part of their graduate program, I would have never imagined the dynamics of explosives in mining. This I put down to the ever changing and rapid development in technology converting blasting techniques into a defined predictable science. The opportunities I have been given have delivered all the appeals from when I first started my study. As a result of my entry into a profession that uses explosives to deliver broken rock in a range of mining and construction projects, through the use of advanced blasting technology and products, my experiences have been wide and varied. These experiences have included the use of OricaÆs i-konÖ detonator technology and blast design software to allow for blasting operations to occur in a range of environmentally sensitive quarrying and construction projects throughout New Zealand, to the implementation of various Orica blast based services aimed at improving dragline dig performance and reducing coal loss thus improve overall mine sustainability in the coal mines of Central Queensland, to the advanced utilisation of Orica explosive products and technology in a number of the worlds largest copper mines in Chile. I have witnessed first hand the blasting technology available within Orica Mining Services to both deliver fundamental changes in mining results and in turn kick off my career with a bang.

Jan 1, 2009

By S D. Golding, K Baublys, V Nanjappa, C J. Moran

Water reuse is becoming an integral component of the water management strategy on mine sites. This practise is being driven by corporate sustainability goals, community and societal pressures to demonstrate improved water stewardship, as well as climate and regulatory pressures. However, water reuse often results in water quality compromise which can then result in decreased recovery through problems in processing circuits, product quality, and an increased likelihood of discharge of water that cannot meet environmental regulatory requirements. On most mine sites, there is usually a disjuncture between water quantity management and water quality management with the latter being managed solely as an environmental problem. It is becoming increasingly clear that water quality and quantity must be managed as an integrated system. In order to integrate water quality and quantity management to achieve multiple objectives the dynamics of water and constituents must be understood. Using examples from a study being conducted at a coal mine in the Bowen Basin, this paper will outline the dynamics of water and salts on the site.

Jan 1, 2009

By L M. Foster, J R. Kellett, G A. McMah

The Great Artesian Basin (GAB) contains one of the largest reserves of fresh water in the world. The volume in storage is enormous, being estimated at nearly 65 000 million megalitres (ML). Development of this resource, dominantly for the pastoral industry, began in the late-1800s and quickly accelerated. With exploitation of the resource, artesian pressures declined almost as rapidly. This loss of head is a result of the total discharge from the basin and much of this discharge is waste of water. The waste through uncontrolled bores and inefficient distribution systems still amounts to about 75 per cent of all discharge. However, the volume in storage has hardly been depleted. The major concern is the effect of withdrawal on artesian pressures. Due to the size of the Basin, the relatively flat gradients and low permeability, the movement of water through the aquifers is extremely slow and independent of recharge. Hence, the normal concepts of sustainable yield (ie discharge should equal recharge) cannot be applied to the Basin as a whole as travel times do not allow for the effect of recharge to be seen away from the outcrop areas within management timeframes. The large volume in storage, though, can provide an extensive buffer to the impacts of temporary water needs. This effect should be considered when assessing the acceptability of fixed life projects such as mines and the extracted volumes from their operations. Identifying a sustainable yield involves balancing the acceptability of the economic, environmental and social costs with the associated discharge and fall in head, to arrive at an acceptable balance.

Jan 1, 2003

The gossan developed from the Whim Creek Cu-Zn-Pb-Ag sulphide deposit, in the Pilbara region of Western Australia, occurs near the top of a ridge in a dissected plateau 01 moderate relief. The gossan is characterized by the abundance of secondary ore minerals which indicates that it is relatively immature, due to climatic conditions and erosional stripping.The abundant presence of secondary carbonates indicates that the low pH generally resulting from sulphide oxidation has been neutralized, probably by the buffering effect of carbonatcs and silicates. Fe, Cu, Pb, 'Ag and Sn have been enriched in the gossan relative to the primary ore, and Mn, Ti, Co and Ni have been strongly depleted; other elements have remained substantially unchanged. The gossan has a strong gcochemical signature characterized by high Cu, Zn, Pb, As, Sb, Sn, Ag and Mo coutents. Boxwork textures are poorly developed, bu't the gossan has other diagnostic mineralogical features including sulphide inclusions in quartz and the presence of residual cassiterite.

Jan 1, 1982

By R Frew, E Wong, G Ferguson

The Chang Jiang Tunnel and Bridge Project, when completed, will provide a fixed link between ShanghaiÆs rapidly developing Pudong District and Chong Ming Island, situated in the Yangtze River delta. The link includes 7.5 km of bored tunnel from the Pudong to the intermediate Changxing Island from where the link comprises viaduct and a cable stayed bridge. The bored section comprises twin 13.7 m internal diameter segmentally lined three-lane highway tunnels. At its deepest point the tunnel will be 55 m below the river. Cross passages will link the two bores for passenger evacuation. Tunnel boring commenced in October 2006 and is scheduled for completion in mid-2009. The paper describes the key features of the design and construction of the bored tunnel by two 14.53 m diameter slurry TBMs and eight cross passages using ground freezing techniques in alluvial sediments. A decision to include light rail below the road deck was taken after the completion of the detailed design. This posed a number of design challenges including passenger evacuation to the road deck, and the redesign of the low point sumps. The various options considered are discussed together with those adopted for construction.

Jan 1, 2008

The selection of the ore haulage system is one of the most crucial decisions made in the development of an underground mining project. The haulage system is, once selected, one of the components of a mine that defines its ability to respond to changes in mining inventory and the market conditions for its products. Over the last decade, in Australia at least, this selection process has largely centred on the debate over the merits of shaft and decline truck haulage. Little attention, if any, was given to the application of inclined conveyor haulage as a real alternative to the shaft and truck haulage. This is despite well established precedents for its application in the underground coal industry and some limited applications in underground metalliferous mines. This paper seeks to explore the case for the application of inclined conveyors as a legitimate ore haulage system for underground mines. The case for conveyor haulage is illustrated by an overview of the application of conveyors at some existing operations, and discussion of what conveyors have to offer as a mine haulage system and the issues that are associated with them. Material drawn from the feasibility studies for NewcrestÆs Ridgeway mine and Telfer Deeps Project is presented as case studies that considered selection of inclined conveyor haulage. The purpose of these case studies is to highlight the value of impartially approaching tasks of this type with a robust plan. This plan should be able to respond to issues identified as the task progresses towards the objective of finding the right solution for an ore haulage system.

Jan 1, 2005

By Bowling K. McG, Hamilton J. D G

The influence of three important para- meters which affect the induration of iron-ore pellets, viz temperature, time, and lime content, have been assessed in terms of internal pellet structure and commonly-used pellet quality criteria. The pellets studied were produced from a typical hematite ore from the Pilbara area of Western Australia, using a 25 cm dia. pot-grate test rig. Isothermal laboratory induration tests were conducted in accordance with a statistically-planned programme. The internal structures were studied by optical microscopic examination of polished sections of the test pellets. The effects of SFCA (silico- ferrite of calcium and aluminium) and slag formation, matrix consolidation and grain modi- fications were studied, and have been related to pellet properties and to the time/temperature histories produced by the firing conditions chosen. The implications of the data for commercial pellet plant operations are discussed.

Jan 1, 1974

The Indonesian province of Papua is a remote jungle-clad region covering the western half of the mountainous island of New Guinea. Despite being relatively under-explored to this day,Papua is home to the greatest mineral success story of the 20th century. The Grasberg/Ertsberg minerals district atop the central dividing range contains the worldÆs largest reserve of both copper and gold (Freeport-McMoRan Copper and Gold, 2002). With large mines at Ok Tedi,Por gera and Lihir,and many well-delineated resources such as Frieda River,Wafi and Hidden Valley, neighbouring Papua New Guinea,the eastern half of New Guinea has enjoyed sustained exploration campaigns for gold and copper since the mid 1960s. The combined Grasberg and PNG exploration successes can be measured in terms of ounces of gold produced over the last decade versus available landmass,conf irming the island of New Guinea and surrounding islands as a world-class destination for gold explorers. Yet despite this obvious regional prospectivity and the profitability of the Grasberg operation, a sustained exploration effort in the Papua province in Indonesia has not been achieved. Periodic political constraints, poor infrastructure, high costs, operational challenges, social and environmental concerns and lack of immediate exploration success often impact exploration investment decisions. Accordingly a lesser number of mineral occurrences have been documented in Papua compared to those seen along tectonic strike in geologically similar Papua New Guinea.

Jan 1, 2004

Broken Hill is situated at an elevation of approximately 1000 ft. above sea-level, on the Barrier Ranges, in the State of New South Wales, Australia. It is approximately 700, 280 and 330 miles from the ports of Sydney, Pirie, and Adelaide, respectively.The summers are usually hot and dusty, with a recorded maximum shade temperature of 114° F. The rainfall averages approximately 9 in. per annum.

Jan 1, 1932