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By I F. Wood

Planning for flooding and assessment of flood impacts are important requirements for mining projects, as they are also for other types of development. With more intense development and concern from the community, supported by government regulatory requirements, assessment of flood concerns and impacts has become of increasing importance. To ensure that flooding issues are fully understood and results presented in an appropriate format, advanced hydraulic analysis procedures have been developed and are beginning to be applied. These procedures must be rigorous in an engineering context but the results must also be readily understood by the community and government agencies. Advanced two-dimensional hydraulic modelling is becoming accepted as an important means of assessing flooding issues for mining projects. With presentation of results from hydraulic models with Geographic Information Systems (GIS), flood impacts can be analysed rigorously and presented clearly. This paper discusses the application of advanced hydraulic modelling in the planning and impact assessment of a major mining project located on a floodplain where there is extensive inundation. The analysis provides for both input to the planning of the project and for detailed assessment of potential impacts. This case study illustrates some important aspects of the application of hydraulic modelling using a two-dimensional modelling to a critical flood design.

Jan 1, 2003

By C B. Smith, G L. Boxer, S W. Moss, A L. Jaques, V Lorenz, M J. Rayner

The Ernest Henry Iron Oxide Copper Gold deposit is hosted in a large dilation between two moderately dipping shear zones found in the footwall and hanging wall of the deposit. These shears are controlled by a large diorite intrusion to the north-east and south-west of the deposit, formed ~1660 Ma. A shear zone dubbed the ‘Interlens’ uncovered through underground workings truncates the main orebody into two lenses, and is hypothesized to have formed in conjunction with the Hanging Wall Shear Zone and Footwall Shear Zone. All three shears dip moderately to the SSE (50–140) from open cut exposures through to the current mining horizon approximately 800 m below the surface. Routine geological work and a capital drilling campaign has identified a significant flexure in these sub parallel ore bounding shears with increasing depth. A shift in shear orientation in the Interlens over approximately 100 m vertically from ~50° to the SSE to a steep, easterly trend (~85° to the east) is observed in both drill core and exposures in the underground workings. It is hypothesized the diorite intrusive to the south-west of the deposit controls the shear zone geometries at depth. The geometry of the Interlens mirrors the surface expression of the Proterozoic package of the orebounding shears to the south-west of the deposit, suggesting the surface geometries of the shear zones are consistent with depth. Additional drilling to explore the validity of this hypothesis is planned for the near future to better understand the structural controls on the Ernest Henry mineralisation with increasing depth.

Mar 22, 2022

By J Vann

Mineral Resource and Ore Reserve estimation is a challenging and demanding field, requiring application of professional knowledge, skill and experience of the highest order. If the many potential pitfalls are to be avoided, however, there are two other requirements which are of equal, if not greater, importance:good communication, and common sense. Estimation of Mineral Resources and particularly of Ore Reserves is almost always a team effort, involving a number of disciplines. Good teamwork requires good communication, both between team members and between the team and other parties having an interest in the process. Breakdown in these lines of communication can have far reaching effects on the project under consideration. The need to use common sense during a Resource or Reserve estimation exercise would seem to be self-evident. It is surprising, however, how often rigid adherence to procedures and methods prevails at the expense of clear thinking, usually with adverse and sometimes fatal effects on the project under consideration. This has become increasingly true as computerised methods have assumed a central role in Resource/Reserve estimation. The critical question that estimators should ask themselves at all stages of the process is: æIs what is being done sensible given the data available, what is known of this deposit and the purpose of the exercise?Æ

Jan 1, 1999

By A D. Price, W J. Germs, O Patterson, T R. Weaver

"Understanding controls on groundwater and surface water flow and quality at mine sites throughout all mine stages is critical to effectively manage environmental impacts over the entire mine life. Monitoring forms is an essential component of this proof of understanding. Typically, monitoring programs at mine sites have been developed in the framework of existing conditions. However; recognition of the challenges of climate change and the performance of mines during recent extreme events in Australia has highlighted the need to develop monitoring programs that are resilient and responsive to changing environmental conditions. Water monitoring programs need to be effective under a range of environmental conditions, potentially not historically experienced.This emerging challenge requires cross-disciplinary teams to work together to understand issues including: representativeness of background conditions to longer-term conditions at the mine site sensitivity of mine and closure designs to changing climate and hydrologic conditions methods of performance (eg water quality or quantity) failure during extreme climate events such as flood or extended drought.These understandings come together in a detailed conceptual and, in many cases, numerical hydrologic model that considers the mine-water environment under a range of conditions. The groundwater, surface water and water quality monitoring programs that are developed from the conceptual model need to be sufficiently responsive to be effective in the face of such changing conditions, with results in turn informing the conceptual model. Extended drought, major floods and changing weather patterns can alter recharge and discharge areas, oxidation profiles and ultimately, the contaminant flux estimates that would have contributed to mine design parameters and performance. Unless these effects are considered in the spatial and temporal design of the monitoring program and within the parameters monitored, the resultant program may fail to capture data that are critical to evaluating environmental impacts from mine sites.Developing and implementing a water monitoring program that considers these issues can build confidence in mine performance under a range of conditions, leading to increased confidence by all stakeholders in long-term mine performance during and after closure.CITATION:Weaver, T R, Price, A D, Patterson, O and Germs, W J, 2013. Developing resilient water monitoring programs in changing climate conditions, in Proceedings Water in Mining 2013, pp 109-114 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 26, 2013

Base metal sulphide mineralisation on the northern end of Great Barrier Island is spatially associated with hypabyssal intermediate to acidic intrusives, in transgressive structures in indurated, complexly deformed greywackes and argillites. Copper predominates in the mineralisation, with minor accompanying lead and zinc and also some gold and silver. However, in some cases lead or zinc may be the dominant constituent. The mineralisation is generally characterised by only narrow envelopes of weak alteration (propyliticassemblages dominated by chlorite and epidote) and with only minor amounts of quartz accompanying the sulphides, which form a cement in zones of hydraulic fracturing. There are two distinct structural settings to the mineralisation: at MinerÆs Head, in a structurally complex situation in a shell-like zone of crackling in hornfelsed greywacke, in association with both north- and east-striking fractures and rubble breccias associated with the apical part of a large intrusive; and in very narrow, but very strike-persistent, 1inear steeply-dipping fracture zones, exposed on the north coast and inland areas near Tataweka.

Jan 1, 1984

By Just G. D

The results of a geostatistical analysis of geochemical data obtained from field measurements are described in the paper. Q values derived from seismic signal rise times for different travel paths in the rock masses were used in the study. Cross-hole seismic measurements made at surface and underground sites formed the basis for the work. Geostatistical estimation of average l/Q values for area of the rock were compared with geological interpretions of rock type distributions. Reasonable correlations were obtained between the two methods of rock quality estimation.

Jan 1, 1988

The value of Australia's education services exports increased to over $15 billion dollars in 2009, placing education as the third overall export earner behind coal and iron ore; however there are concerns over the impact of emerging policies on the future of both the industry and the provision of mining education. Policies have impacts on the growing number of international rankings (or league tables) of mining jurisdictions and universities. A high position in such rankings might be used as a measure of perceived quality with benefit to those at the top and to the detriment to those lower down.    Top performing companies in the relatively new domain of sustainability have been shown to achieve better financial performance than their industry competitors, assisting them in attracting top quality committed staff, hence positioning themselves well for the future. The world's mining companies, jurisdictions and universities are now ranked with results in the public domain. It is argued as to the validity of the data or perceptions used in such rankings, but there is no doubt they are influential in determining the flow of dollars around the globe. By investing your pension fund assets in the shares of the top performing companies, by placing your exploration dollars in a country at the top of such a list of attractive jurisdictions, attending or recruiting from a University at the top of the rankings - risk must surely be reduced?   While savings and risk reduction can undoubtedly result from the introduction of new technologies developed through appropriate R&D (the other core activity of a university), the maintenance of a very high level of exploration and production performance through dedicated highly skilled staff every hour of every day quietly improves financial performance, while avoiding safety, environmental and/or community incidents (ie protects the 'triple bottom line'). As always risk reduction comes down to enabling quality people to do a quality job - through the actions of such people we can sustain the global mining industry and secure our social license to operate. However, there is global concern over where the numbers of such people, including those with the recently required skills in sustainability, are going to come from.   This presentation will discuss some of the complexity and interactions involved in the development of such rankings, the dangers inherent in their simple acceptance and use, plus indicate some of the directions mining educators might take to sustain and increase the supply of quality graduates to the global mining industry. This is an ABSTRACT ONLY. No paper was prepared for this presentation.

Jun 1, 2010

By A Havenga, F, J Hough, R Grobbelaar

After the closure of mines they naturally start to fill up with water. As a result, hydraulic gradients develop between adjacent mines and different hydraulic water pressures are exerted onto peripheral areas or compartments within mines. This results in water flow between mines, or onto the surface. This flow is referred to as intermine flow. The geometry of the collieries in the central Witbank Coalfield make intermine flow possible in several areas. Since the Department of Water Affairs and Forestry declared intermine flow as one of its greatest concerns for granting closure to South African mines, much research into this phenomenon has been undertaken. The importance of the quantification lies in the DepartmentÆs goal of sustainable water management, and the possible long-term financial implications these flows could have for individual mines. The challenges of determining intermine flow are numerous, and attention is focused on the identification of areas where these flows can take place. Detailed mining plans on a regional scale are required, and detailed coal-seam floor data are combined to provide targets for possible interaction between these mines. The quantification of these flows is problematic due to the uncertainties regarding geometrical configurations and the variation in site-specific hydraulic characteristics of the coal and overlying lithilogical layers. To this end, use has been made of several analytic solutions and numerical flow modelling. Stage curves (volume versus elevation curves) for the opencast and underground workings have been calculated and first-order estimates for intermine flow or decant from these areas have been determined. The numerical modelling methodology entailed a down-scaling approach, starting with a broad regional model covering the entire area, followed by modelling the interactions between interconnected mines and finally looking in detail at the major areas of interaction. By considering different scenarios within the context of these flows, possible management options for intermine flow can be evaluated in terms of volumes and qualities that might emanate in the post-closure phases. Challenges for the future include obtaining site-specific information on the groundwater hydraulics and acceptable ranges for model parameters, and verifying model results over time.

Jan 1, 2003

The mineral matter has been isolated from a selection of Australian bituminous coals using low temperature (radio-frequency) oxidation or hydrogen peroxidation techniques and the species present identified by x-raydiffraction. Quartz, kaolinite, and a range of mixed layer clay minerals are the dominant constituents of the coals studied, with carbonate, sulphate, and phosphate minerals abundant in some samples. The clay bands thatoccur within these coal seams contain similar mineral assemblages to the coals themselves, but the lutites that form the inter-seam strata have a markedly different mineralogy, characterized by abundant quartz andillite and a low kaolinite content.The kaolinite is thought to have formed chiefly by interaction of silica and alumina in the waters of the coal swamp, aided by the catalytic action of organic acids, while most of the other clay minerals are probablydetrital. The absence of illite from Australian coals is not fully understood, but it may reflect the action of organic acids on the detritus in the swamp, coupled with deposition in freshwater rather thanmarine conditions. Pyrite, although present in some coal samples when fresh, may undergo oxidation during storage to form a number of sulphate minerals, some of which may interact with any calcite present toform gypsum.The mineral matter assemblage in the coal determines to a great extent the fusion characteristics of the ash.Unless abundant carbonates are present, coals with kaolinite-rich assemblages have a very refractory ash, while those rich in chlorite or montmorillonite have ash fusion temperatures between 1000 and 1300°C. Theinfluence of the minerals on coal preparation and coking properties is also brieflY discussed, as well as the potential of mineral matter studies in coal seam correlation.

Jan 1, 1978

By P Wahyono, H Vega, S Riza, P Vergara, P Gonzalez-Carbonell

PT Freeport Indonesia (PTFI), operating in the Ertsberg Mining District in the Province of Papua, is developing the Grasberg Block Cave copper-gold mine. The site aims to output 160 000 t/d and will be located underneath the current Grasberg Open Pit. Initial studies of the potential to develop a block cave mine in the Grasberg orebody have revealed that the mine will require significant volumes of air. The Grasberg Block Cave (GBC) project requires four primary fans (3750 kW each) to support production at full capacity.Fan #1 commissioning was accomplished successfully on 9 February 2012. However, Fan #2 chamber, which is separated by a 20 m pillar, had not been completed. The main challenge was Fan #2 chamber still needed to be benched. The risk of damage to the critical infrastructure in Fan #1 chamber, including ground support, cracks in pedestals, and misalignment in the impeller shaft were considered. The challenges were blasting the bench without damaging the surrounding infrastructure, completing the work safely and meeting the schedule. This was achieved with the engineering control methodology. This paper summarises the benching process of Fan #2 chamber and its impact upon Fan #1.CITATION:Vega, H, Riza, S, Gonzalez-Carbonell, P, Wahyono, P and Vergara, P, 2013. Excavating an underground primary fan chamber that is adjacent to a fully operational primary fan in PT Freeport Indonesia's Grasberg Block Cave Mine, in Proceedings The Australian Mine Ventilation Conference , pp 115-122 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By Stitt P. H

In Australia, the term "heavy mineral deposits" is used to denote sands which contain variable but economic quantities of the minerals rutile, ilmenite and zircon, often with minor amounts of monazite and xenotime as co-products. Australia has been a significant producer of rutile, ilmenite and zircon from such sands for fifty years and has long been the leading producer of rutile and zircon. The industry had its beginnings with the mining of present day beaches in northern NSW in 1934. Early work was small scale and in some cases involved hand winning of naturally concen- trated mineral for direct export. During World War II and immediately after the industry became increasingly mechanised and by the 1970s on the east coast operated between Newcastle, NSW north to Fraser Island in Queensland. Deposits worked included present day beaches, fossil strand lines up to 5 km or more inland from the present coast and aeolian concentrations. In the mid 1950s, operations commenced on the west coast of WA, south of Perth. Western Australian mineral sands tend to be rich in ilmenite as compared to the east coast. However the WA ilmenites are lower in chrome oxide and make a better syn- thetic rutile feedstock.

Jan 1, 1988

On the Hauraki goldfields, within the limits of Cape Colville Peninsula, the Paheozoic rocks are confined to the district north of a line drawn from Mercury Bay on the east coast to Rocky Point on the shore of the Frith of Thames. South of Kennedy's Bay they are developed on the east coast only at Kuaotunu, at which place gold mining is carried on in sandstones and slates of this age. Between Tapu Creek and Coromandel there is, along and adjacent to the shore of the gulf, a very considerable development of PaJreozoic and in part of Trias rocks, and between the Tiki Stream and the northern end of Tokatea Hill, along the western slope of the main range, lies the special area of the Palreozoic or carboniferous rocks that have more particularly to be dealt with in this paper. The same formation has a large devolpment between Cabbage Bay and the northern slopes of Moehau, and appears to the water marge on both sides of this part of the peninsula.In this part they are of special interest as having, on the west spur of Moehau, a considerable variety of dyke rocks intruded into the sedimentaries, the interest in which is increased by the fact that these dykes theIllselves are of Palreozoic age and correspond to the dykes that are so' abundant in the Tokatea-Tiki area. It is this Tokatea-Tiki area as a goldfield, and its rocks as distinguished from later volcanic' products' on other parts 'of the peninsula...

Jan 1, 1903

The mining industry provides employment opportunities for individuals from a wide variety of disciplines. Solid Energy New Zealand Limited (Solid Energy) is New ZealandÆs largest coal mining company and the career opportunities for school leaver trainees and university graduates are numerous. Solid Energy also provides fixed term opportunities for consultants and contracting companies, who complement the wealth of knowledge already within the company.   Focussing on Stockton Mine and my involvement there as an Engineering Geologist, this paper looks at Stockton Mine and the Stockton Water Management Project and outlines the career paths of other young professionals also working at Stockton.

Jan 1, 2007

By R J. deMelo, A, V Suckal, R A. Vilela

Massive hematite ore (MHO) is a special high-grade iron ore used as lump ore in the process of obtaining direct reduced iron (DRI). The influence of porosity on the reducibility was investigated using optical and scanning electron microscopes. Hematite is the main component of the samples and occurs as granular crystals (10 ¦m), microplates (1 ¦m) and euhedral martite (10 to 30 ¦m). Quartz, maghemite, kenomagnetite and goethite are minor components. Primary micropores (+ to 1 ¦m) are associated with microplaty crystals that fill cavities between granular hematite. Secondary micropores (+ to 5 ¦m) related to euhedral martite crystals are the most important. The total porosity of weathered samples, measured using nitrogen adsorption and mercury injection, attains values up to 18 per cent, whereas unweathered samples have a porosity less than 2.5 per cent. Varajpo et al, 2002 showed that reducibility is strongly enhanced by porosity and this work shows that reducibility can be indirectly evaluated by bulk density.

Jan 1, 2002

By Robinson WB

An accurate and rapid assessment of coal resources, such as that provided by computer modelling, forms an intergral role in evaluating CSR's coal deposits for future development. An in-house system utilising a number of geological, engineering, costing and financial evaluation routines has been developed for DEC VAX computers. The system is currently being upgraded and enhanced to meet the demands at the various mine sites. Computer modelling of the geology is performed on encoded drillhole information and coal core chemical and physical analyses. A conceptual mine plan is formulated then digitized and superimposed on the geological model. Insitu and product coal reserves and qualities as well as overburden and parting quantities are then calculated for each strip or block. These strip parameters are then transferred to the mine scheduling routines to determine the most efficient mining sequence for the mine plan. Cost factors and scheduling data for equipment specified in the conceptual mine plan are used in the mine costing subsystem. The financial subsystem then evaluates the likely return on investment. Future enhancements to the system include improvements in the response time through the introduction of interactive graphics, the direct interfacing of geophysical and analytical data, and further development of a geotechnical'database.

Jan 1, 1983

Formation of either sodium jarosite or lead jarosite from concentrated chloride solutions containing small concentrations of sulphate has been demonstrated. Sodium jarosite is precipitated at 95-100°C from FeC13-FeCI2-NaCI-PbCI2 solutions to which was added Na2SO4 or Li2SO4 in amounts greater than 0.05 M. In the absence of alkali metal ions capable of forming jarosites, lead jarosite was precipitated from either FeCI3-PbCI2 or FeCI3-FeCI2-LiCI-PbCI2 solutions to which had been added small amounts of sulphate. Many of the factors affecting jarosite precipitation from chloride solution have been elucidated, and the most critical were sulphate concentration and initial pH. Concentrations of HCI in excess of O. I M essentially suppressed the production of jarosite in chloride media. Alkali jarosite, precipitated in the presence of dissolved lead, incorporates a small amount of this metal into the alkali jarosite lattice. Small but significant amounts of copper can also be incorporated into alkali jarosite and the amount is further increased in the presence of lead. Other divalent base metals such as Zn, Cd or Ni are not significantly precipitated. Sulphate control in either FeCI3 or FeCl3-NaCI leaching systems could likely be maintained by jarosite precipitation provided that the acid concentration of the solution was low.

Jan 1, 1981

By P J Savory

Ranger is a uranium mining operation located within one of the most environmentally sensitive regions of Australia. Geology has played an important role in mine planning, operations and rehabilitation since discovery of the deposits 25 years ago. The Ranger orebodies have a reserve total of 166 300 tonnes of U308 including 90 400 tonnes of U308 at North Ranger. At current milling rates these reserves give a mine life greater than 40 years. The uranium is hosted in Lower Proterozoic rocks of the Cahill I ormation and is associated with strong chlorite alteration. In pit grade control involves the use of calibrated probes and a radiometric truck discriminator allowing fast, accurate grade determination of material. Ore is defined at a cut-off grade of 0.2 per cent U308. Mineralised material is defined by the Uranium Mining (Environmental Control) Act 1979 (UMEC Act) at a grade of 0.02 per cent U30s. Natural water levels in the #1 Pit area vary as much as 7.5 metres between wet and dry seasons. Ground water inflow into the pit during the dry season is 600 m3/day. No significant slope failures have occurred in the pit. The environmental impact of mining operations is constantly monitored. Rehabilitation of non-mineralised stockpiles is ongoing. This paper discusses the interaction between geology, hydrogeology, rock mechanics and grade control with the present mining operation.

Jan 1, 1994

By K Whelan

The Land Access Branch of the Mines Division of the Northern Territory Department of Mines and Energy is responsible for Aboriginal Liaison and cross-cultural matters that affect the Department. In essence, it exists to provide a basis for communication between the Department, industry. Aboriginal organisations and Traditional Owners. The paper outlines the various ways in which this is accomplished including the preparation of detriment submissions for pending land claim hearings, the use of promotional material to support access to Aboriginal Land for NTGS Mapping Programs and field work, and advice/assistance on exploration and mining issues.

Jan 1, 1994

By S Servant

In the mine of this study, cemented hydraulic backfill is placed under the form of a slurry at a percentage of solid by weight varying from 50 to 65 per cent. This slurry settles and cures in the stope. During this process an important amount of water must be drained from the stope. Field observations in the case studied here show that the geometry of the drains system has a significant impact on the drainage of the stopes. The mode of filling produces a backfill showing an evident stratification typical of a sedimentation process. In situ observations on this material show that this stratification translates into a very strong heterogeneity in the physical properties of the cemented backfill. This heterogeneity should affect the hydraulic conductivity of the backfill in the stope. In order to study this aspect, finite element simulations were performed. This paper presents the results of these simulations, where the impact of this stratification on hydraulic conductivity is related to the performance of the backfill drainage system for various geometry. This preliminary study is aimed at providing a better understanding of the role of the drains in the dewatering process of the backfilled stope in the case of this mine.

Jan 1, 1998

By Servant S

In the mine of this study, cemented hydraulic backfill is placed under the form of a slurry at a percentage of solid by weight varying from 50 to 65 per cent. This slurry settles and cures in the stope. During this process an important amount of water must be drained from the scope. Field observations in the case studied here show that the geometry of the drains system has a significant impact on the drainage of the stopes. The mode of filling produces a backfill showing an evident stratification typical of a sedimentation process. In situ observations on this material show that this stratification translates into a very strong heterogeneity in the physical properties of the cemented backfill. This heterogeneity should affect the hydraulic conductivity of the backfill in the scope. In order to study this aspect, finite element simulations were performed. This paper presents the results of these simulations, where the impact of this stratification on hydraulic conductivity is related to the performance of the backfill drainage system for various geometry. This preliminary study is aimed at providing a better understanding of the role of the drains in the dewatering process of the backfilled stope in the case of this Mine.

Jan 1, 1998