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By M Pepper, C R. Roche, G M. Mudd

"The Australian mining industries approach to life-of-mine planning has improved considerably in recent decades. It now needs to be matched by, and embedded in, mining governance systems that utilise a comprehensive whole-of-mine-life approach within a jurisdictional, industry and regional regime rather than just focusing on specific impacts in isolation. The need for a more comprehensive approach is supported by the many mining legacies, from historic, recent and some operating mine sites around Australia. There are sites that are leaving enduring environmental, community and public health impacts that are yet to be accurately assessed. While a number of these sites in Australia are estimated to be more than 50 000, this is probably an underestimation, with a lack of data and different state-based approaches complicating attempts to quantify mining legacies as a national issue. Qualitative assessments about the extent and nature of mining legacy impacts on nature and communities across Australia are also required if we are to understand and avoid ongoing and future mining legacies.This paper commences with an exploration of mining legacies as an umbrella term for previously mined, abandoned, orphan, derelict or neglected sites. This is followed by a discussion of the current status of mining legacies as an Australia-wide issue, contrasting the Australian response with overseas examples. Common themes from past workshops are explored recognising that mining legacies are a growing public policy issue and identifying key ingredients for a successful response. Supporting this, and based on national data which re-enforces the need for action, is the changing scale and intensity of mining in Australia that, while lowering costs for mine operators, increases the liability that may eventually fall to the state if mine sites are not rehabilitated effectively. Though a national issue, mining is a state and territory responsibility, so the current approach to mining legacies is then examined state-by-state. Given the widespread application and recent changes to bonds and levies in Western Australia (WA) and the Northern Territory (NT) the merits of both are examined with reference to specific case studies. Despite the current division of responsibility and diversity of approaches, however, mining legacies remain a significant and growing problem with a recognised need and repeated call for cooperation and coordination at a national and international level. Future action is addressed in the final section with reference to liability, responsibility, industry reputation, regulation and leadership.CITATION:Pepper, M, Roche, C R and Mudd, G M, 2014. Mining legacies – understanding life-of-mine across time and space, in Proceedings Life-of-Mine 2014 , pp 449–466 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 16, 2014

By I M. Platten, Y Xie

Sampling protocols that are designed to suit the mineralisation style will result in a reduction of the nugget effect and hence resource risk. The a priori need for all sampling programs is the effective characterisation of the mineralisation type(s) to support optimisation. This requires a program of sampling for sampling followed by holistic characterisation. At each end of the coarse-gold to fine-gold spectrum, the samplability of a deposit ranges from relatively simple for fine-grained disseminated gold particles, through to extremely difficult for coarse nuggety mineralisation. Many deposits contain a proportion of both particle size types. The proportion and size of coarse gold particles has a direct impact on the effectiveness of sampling, where coarser particles will require larger samples and more specialised protocols. The nature of mineralisation geology/mineralogy and associated gold particle sizing can only be determined by sampling to facilitate optimised protocols. Mineralogical studies, focusing on particle size, particle clustering and distribution in host minerals, are required as part of wider paragenetic and metallurgical investigations. This paper discusses the role of mineralogical studies in the characterisation of gold ores for sampling optimisation through a series of case studies.

Jan 1, 2008

By P Holtham, K Duffy, W Valery, A Jankovic

In the face of increasing energy costs, limited water resources, more stringent legislation, and lower feed grades, the mining industry is searching for more sustainable technologies and practices. Metso Process Technology and Innovation (PTI) is undertaking a research project, ‘improving the resource and eco-efficiency of mining operations’, to help the industry meet these challenges. The project is investigating alternatives in mining and processing that reduce energy and water consumption, minimise emissions and waste, and maximise the value recovered from the deposit. The targets are to reduce energy usage by more than 30 per cent and greenhouse gas emissions by more than 50 per cent compared to current practice.Key areas of interest were identified across mining and processing operations. These were grouped into the following interrelated work areas for investigation: high intensity selective blasting, in-pit crushing and conveying, preconcentration, energy efficient comminution circuits and technologies, coarse particle flotation, and water recovery optimisation. Investigations have included reviews of industrial data, modelling, simulation, and laboratory and pilot scale trials. In some areas industrial scale trials will commence shortly. This paper discusses the investigations and key findings from the project so far; highlighting the possibilities for reducing energy consumption, water usage and carbon emissions. A particular mining process may incorporate any combination of the alternatives identified and requires tailored solutions based on a detailed understanding of the ore deposit, the process and local conditions. The focus is on improving resource efficiency; creating more value with less impact and consequently a better economic return from the available resource. Technologies exist today that can transform mining into a more efficient industry for tomorrow.CITATION:Duffy, K, Valery, W, Jankovic, A and Holtham, P, 2015. Resource efficient mining processes of tomorrow, in Proceedings Third International Future Mining Conference, pp 227–238 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By R L. Chaney, M Mahoney

Mine and ore beneficiation wastes and smelter contaminated soils often cause phytotoxicity and threaten adverse environmental effects if not remediated. Science has clarified both the risks from soil metals and methods to alleviate those risks that can be applied at low cost. Phytoremediation is a family of plant and agronomy based technologies to deal with environmental aspects of sites requiring remediation. If valid risk assessment indicates that metals comprise risk, phytostabilisation may be used to alleviate that risk for most contaminated sites. In particular, Zn-Pb, Cu and Ni mine and smelter sites are readily remediated by making the soil calcareous and fertile, with added organic and metal sorbent amendments that include soil microbes to ‘revitalise’ the soil. In each case, the soil fertility and causes of phytotoxicity should be clarified by agricultural soil extractions, and the combination of amendments required to improve fertility and reverse phytotoxicity identified and found locally. In contrast with phytostabilisation, phytoextraction/phytomining uses rare metal hyperaccumulator plants and agronomic management to maximise annual phytoextraction of soil elements into plant shoots for harvest, ashing and use as a metal ore. Plants that accumulate more than two per cent Ni in shoots, and yield 10–20 t ha-1 dry biomass yield 200–400 kg Ni ha-1, which has value greater than all common agricultural crops. Considering the value of elements, existence of hyperaccumulator plants and demonstrated agronomic management for Ni phytomining, it is clear that mine sites and Ni mineralised subore-grade serpentine soils can be phytomined economically as an agricultural mining technology. A team developed agronomic methods and improved cultivars of Alyssum, which can be profitably grown on temperate zone Ni mineralised or contaminated soils. Plant species for tropical ultramafic soil materials have been identified. Phytoextraction is also strongly needed to remove Cd from rice soils to prevent human disease from soil Cd.CITATION:Chaney, R?L?and?Mahoney, M, 2014. Phytostabilisation and phytomining – principles and successes, in Proceedings Life-of-Mine 2014 , pp 3–16 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By P Walker, I Crnkovic, D Bennett

The Phu Kham deposit represents a copper-gold porphyry system, with mineralisation present in skarn, stockwork and disseminated styles. Significant folding and alteration events have created a complex heterogeneous mineralogy horizon. Weathering and water table contact have created a leached zone, overlying transition zones with supergene chalcocite- dominant secondary copper mineralisation and clay-rich gangue. Primary ore copper mineralisation is mainly chalcopyrite with minor bornite. The major challenges to the copper-gold flotation process are a wide size distribution of chalcopyrite mineralisation and poor primary grind liberation, a high pyrite content in skarn ore requiring aggressive pyrite depression conditions, clay-rich gangue and non-sulfide copper mineralisation in weathered zones, and a significant association of gold with pyrite.The Phu Kham concentrator has been developed as a conventional semi-autogenous grinding (SAG) and ball milling circuit followed by selective rougher flotation, regrinding and cleaner flotation to produce a copper concentrate containing payable gold and silver values. The concentrator flow sheet design offered a capital efficient compromise between high copper recovery bulk sulfide flotation with large cleaning capacity, and lower recovery copper selective rougher flotation to ensure concentrate specification of 24 per cent copper grade could be achieved. This paper will examine and discuss concentrator flow sheet development, including projects implemented since commissioning to improve copper recovery, and future projects designed to maintain and enhance copper in concentrate production with decreasing copper grade and increasing pyrite content of ore feed, and increasing hardness of primary ore.CITATION:Bennett, D, Crnkovic, I and Walker, P, 2012. Recent process developments at the Phu Kham Copper-Gold Concentrator, Laos, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 257-272 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By I Zulkarnain, H Permana, R A. Binns

Through an ambitious but relatively low-cost program of marine fieldwork, laboratory investigations and technology-transfer and training activities, three Indonesia-Australia-led marine expeditions were undertaken aboard KR Baruna Jaya VIII between 2001 and 2003. These IASSHA (Indonesia-Australia Survey for Submarine Hydrothermal Activity) cruises have sought to discover and investigate a variety of potential ore forming hydrothermal systems in a range of tectonic settings. All cruises have been successful, both scientifically and from the point of view of training, creation of capabilities and capacity building for such research in Indonesia. Over 60 scientists and technicians from Indonesian and Australian institutions and agencies have been involved. Three new sites and a possible fourth site of hydrothermal activity were discovered in the Sangihe arc in northern Sulawesi. Surveys in the Tomini basin tested a hypothesis based on previous data which suggested this might be an isolated anoxic, brine-filled basin over 2000 m deep where igneous heat sources existed to generate hydrothermal mineralisation. The bay, however, was found to be open to adjacent deep ocean circulation, and there was no evidence of massive base metal sulfides. Subdued evidence of hydrothermal activity was found in the Sunda Strait associated with the famous Krakatau volcano and the extension of the seismically active Semangko Fault. The BANDAMIN program (Indonesia-Germany) covered a portion of the Banda arc in eastern Indonesia, and also found evidence of recent hydrothermal activity and epithermal sulfide mineralisation.

Jan 1, 2004

By R Wheeler, E Stalenberg, J Lemon, M S. Crowther, D Lunney, K Ross

Gunnedah, in north-western New South Wales (NSW), including the town, the surrounding Liverpool Plains and the Pilliga forests to the west, are currently the subject of intense mining interest for coal and coal seam gas. Achieving positive outcomes for koala conservation on mined landscapes will require a sound grasp of koala ecology; and local knowledge of koala movements, tree choice and associated threats to the continued survival of koalas, particularly roadkill from increased mining infrastructure. This requires a research-oriented approach to testing ideas applicable to the long-term survival of koala populations. Our recent koala research in NSW has shown that, in 2006, Gunnedah had the largest koala population west of the Great Dividing Range, and the only population in NSW that was expanding. That prompted us to instigate a detailed study in 2008 - 2011 to determine, inter alia, whether the koalas were using trees that were planted in the 1990s to cope with rising soil salinity. Our GPS-tracking has shown that regrowth trees as young as ten years old can attract koalas. In 2009, the demise of about a quarter of the local koala population from an intense heatwave gave us a foretaste of how habitat and climate change interrelate at the landscape scale. We are now examining the optimal combinations of tree choice, and patch size and shape, for habitat restoration. This will be relevant to local coal seam gas and coal mine proposals, and ongoing mitigation actions. The Senate enquiry of September 2011 on the koala and demonstrated the intense public interest in the survival of this iconic species. Its subsequent listing for Queensland and NSW under the Commonwealth Environmental Protection and Biodiversity Conservation Act 1999 further raises its profile and obligations for management of koalas and their habitat. It will take considerable effort to manage the Liverpool Plains koala population for the next 50 years in the face of extensive land-use changes from mining, and the attendant threats from road kill, compounded by the new threat of climate change manifesting itself as an increased frequency of heatwaves and more severe droughts. This paper describes the research that underpins these conclusions, identifies some of the research approaches needed, argues for working strategically now, rather than try to patch up matters after the event, and presents a set of guides for environmental plantings. CITATION:Lunney, D, Lemon, J, Crowther, M S, Stalenberg, E, Ross, K and Wheeler, R, 2012. An ecological approach to koala conservation in a mined landscape, in Proceedings Life-of-Mine 2012 , pp 343-352 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

During operations, mining and metallurgical processes may generate effluents such as tailings water, acid mine drainage (AMD) and seepage and process acid streams. Depending on the type of ore and the metallurgical process, these effluents may contain one or more toxic compounds (eg acidity or alkalinity, cyanide, ammonia and/or nitrate, heavy metals, total suspended solids (TSS), sulfate) in elevated concentrations requiring treatment before their discharge to the environment or recycle/reuse in the process. Natural oxidation of sulfide minerals present in mining wastes (eg tailings and waste rock) at mining sites may generate AMD, which is characterised as a low pH, high acidity effluent containing heavy metals and sulfate. If generation of AMD cannot be controlled and/or prevented, AMD needs to be collected and treated for neutralisation of acidity and reduction of metals and TSS to meet regulated water quality standards. It is important to note that some of these compounds may persist in run-off from mine sites, even after the mine and processing facilities are decommissioned. Treatment of mining and metallurgical process effluents can be accomplished by means of various physical, chemical and/or biological methods. The mode of process application may vary from the use of either specifically designed, controlled and automated facilities or passive systems. Lime neutralisation and precipitation is the most common method used in the mining industry to treat AMD. To reduce the problems associated with disposal and long-term storage of the resulting sludge, the use of a high-density sludge process (HDS) has become a preferred option. The use of other chemical reagents, waste or by-products from other industries, and biological sulfate reduction methods can also be considered as viable options for site-specific situations. Recently, several passive treatment systems have been designed and successfully operated, even in the cold North American climate. This paper will discuss available options and provide insights for selecting a suitable method for a given situation using case studies from projects conducted by Golder Associates around the world over the last decade.

Jan 1, 2006

A series of petrological studies were carried out on the characteristics of alteration and mineralisation in mainly structural-controlled (Deep Star, Meikle, Deep Post) and predominantly lithological-controlled (Post-Betze-Screamer and West Leeville) gold deposits in the northern district of the Carlin trend, Nevada. Alteration and mineralisation in these deposits are hosted in a sequence of calcareous clastic units of the Devonian Popovich Formation, into which have been emplaced a number of Jurassic intrusions, and syn- to post-mineral Eocene dikes. Four hydrothermal events have been recognised in these deposits: an initial Devonian base metal system and early diagenesis; a Mississippian stage of alteration in conjunction with burial metamorphism; contact and hydrothermal alteration and base metal-gold mineralisation associated with the emplacement of the Jurassic intrusions; and a Carlin-style gold system related to Eocene magmatism.

Jan 1, 2004

By C J. Unger, A M. Lechner, A Walton, V Glenn, M Edraki, D R. Mulligan

In Australia, responsibility for abandoned mines can be unclear. With a few exceptions, state and territory governments have become responsible for abandoned mines on Crown land and private landholders are responsible for abandoned mines on freehold land. Abandoned mines pose risks and opportunities across the full suite of sustainability themes (environmental, human health and safety, socio-economic and community development) after mining ceases.Across Australia, there are more than 50 000 abandoned mines recorded, ranging in size from individual shafts to large polluting open cut mines. Addressing the safety and environmental impacts of these sites, as well as the socio-economic development opportunities of significant rehabilitation projects, requires the implementation of effective policies and programs. Qualitatively defined graded scales or ‘rubrics’ have been used for many years in student assessment and increasingly in the performance assessment of other sectors (Davidson, 2005). While risk-based maturity models have been used for safety prioritisation (Westrum, 1993; Hudson, 2007; DRET, 2008; Hancock, 2010) and evaluation of organisational development (Esteves et al, 2010), this paper is the first to adapt maturity models for the evaluation of abandoned mine rehabilitation programs in Australia.In this paper, we used indicators based on the national policy for abandoned mines to assess the maturity of abandoned mine programs. Fourteen elements of maturity were identified (Unger et al, 2012) under the five chapters of the national policy for abandoned mines (MCMPR and MCA, 2010). Jurisdictions were then evaluated and ranked on their maturity on the basis of information that was web-accessible. Information transparency of abandoned mines policies and programs is in itself one element of the maturity chart. Each jurisdiction in Australia was compared with one another and with a Canadian jurisdiction; the British Columbia (BC) Crown Contaminated Sites Program (CCSP), which represents leading practice (Unger, 2009; Unger et al, 2012).Our research found that in some jurisdictions in Australia there is little or no information on abandoned mine programs or individual abandoned mine sites on government websites, while other jurisdictions provided very detailed program information on planning, funding and implementation. Each jurisdiction in Australia, for which web-based information was available, had some elements where they were more mature than other Australian jurisdictions. For some elements, maturity ranked equivalent to the BC CCSP, but most Australian jurisdictions were less mature. There was only one element where a single Australian jurisdiction ranked higher than the BC program in maturity. Legacy mine policies, programs, priorities and funding information via departmental websites are easier to find in some jurisdictions, indicating progression toward greater transparency and more mature programs. A systematic approach to monitoring and evaluating abandoned mines programs is essential for accountability as it can demonstrate liability reduction over time and continual improvement. The maturity model approach can provide both a measure of progress over time as well as a tool to support the implementation of the national policy for abandoned mines (MCMPR and MCA, 2010).CITATION:Unger, C J, Lechner, A M, Walton, A, Glenn, V, Edraki, M and Mulligan, D R, 2014. Maturity of jurisdictional abandoned mine programs in Australia based on web-accessible information, in Proceedings Life-of-Mine 2014 , pp 467–480 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By J M. Santini, I C. A Streimann

Arsenic is a naturally occurring element in the environment and is toxic to biological systems. Arsenic can exist in the environment in the following redox states, arsenite (+3), arsenate (+5), arsine (-3) and elemental (0) (Oremland and Stolz, 2003). Arsenic is released into the environment by natural and anthropogenic activities such as rock weathering and ore mining, respectively. Such activities result in the release of the soluble inorganic arsenic oxyanions, arsenite and arsenate. The redox state of arsenic in the environment is influenced by a number of factors including, redox potential, pH and microorganisms (Irgolic et al, 1977; Genc-Fuhrman, Tjell and McConchie, 2004). Recently, the ability of microorganisms to influence the cycling of arsenic in the environment has attracted much attention. Microorganisms that can oxidise arsenite and reduce arsenate have been isolated and the mechanisms of arsenic metabolism are currently being investigated. The differences between arsenic resistance and arsenic metabolism are being revealed. The role of microorganisms in the release of arsenic into the environment is of particular importance with arsenic contamination of waters causing the death of millions of people worldwide, due to the consumption of contaminated water (Vasken Aposhian et al, 2003; Islam et al, 2004).

Jan 1, 2004

By S C. Dominy

Gravity amenable gold ores are those that after comminution produce liberated particles, composites and/or carriers that can be recovered by gravity separation means. Recovery depends upon mineralisation type and the comminution and concentration method used. Any in situ ore with more than 20 per cent of gold greater than 100 µm in size is likely to have a strong gravity recoverable component. A less traditional approach is where the gold is sulfide-locked and the gold carrier plus any liberated gold is recovered via continuous gravity recovery following fine crushing. Specific tests are undertaken to determine the level of gravity amenable gold within a deposit. The principal methodology is the gravity recoverable gold (GRG) test, which consists of three sequential liberation and recovery stages. For continuous gravity recovery (CGR), the sample is fed over a laboratory Wilfley table to simulate continuous recovery of the gold. Tails from the feed can be progressively re-ground and re-tabled to develop a grade-recovery curve. Primary geology and gold particle size-distribution have a strong effect on the mass of sample required to provide representative results for both tests. Where low-grade ore contains very coarse gold, substantially larger sample masses are required. Experience has shown that GRG and CGR values can vary throughout an orebody, particularly within different geological-grade domains. A testing regime must consider sample frequency and support.

Sep 5, 2011

By J M. Galvin

History attests to the catastrophic consequences that fire, explosion and contaminated, noxious andirrespirable atmospheres can have for workplace health and safety in underground coal mining. It also confirms that fires and explosions present the greatest risk of partial or total loss of underground mines and equipment and that this risk continues to materialise. The design, implementation, operation and maintenance of the mine ventilation system are core controls for managing the hazards associated with these risks, both for preventing them from materialising and for mitigating their consequences if they do materialise. These are most effective when embedded in a risk management approach.

Oct 12, 2022

By J L. Kerr, J Beyer-Robson, S Vink

Driven by an increasing need for water conservation, coal mine operators in the upper Isaac River catchment have placed significant emphasis upon the reuse of water. This initiative led to an overall increase in the salinity of mine waters. The ionic composition of this water differs from local stream water in that concentrations of sulfate are higher than average stream concentrations by ten per cent, while concentrations of bicarbonate and calcium are lower. When this water is discharged into ephemeral streams in semi-arid environments there is potential for this increased salinity and altered ionic composition to impact upon the ecosystem processes mediated by micro-organisms in river sediments.We have measured nitrification, denitrification and methanogenesis rates in a series of lab experiments using sediments from Isaac River catchment streams and found that salinity affects these processes in different ways and to different degrees. Process rates were shown to differ seasonally between samples taken from the same location and habitat type and also between different habitat types at the same time and location. Both aerobic and anaerobic process rates were higher in surface sediments and it is likely that this activity is associated with surface biofilms. Furthermore, we have shown that the ecosystem processes we have measured are limited by the availability of carbon in the sediments.The management implications of these findings for mine releases into ephemeral streams will be discussed.CITATION:Kerr, J L, Vink, S and Beyer-Robson, J, 2013. The effects of increased salinity on microbially mediated ecosystem processes in ephemeral streams, in Proceedings Water in Mining 2013 , pp 121-134 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By G Malherbe, J Gonzalez, D C. Franklin, J Bassan, C T. Farrelly

To respond to ever-increasing challenges, mining companies have been experimenting with new business models and technologies in order to speed mine development, production, processing and transport. The various experiments involve mobile access to data, intelligent sensors, advanced analytics, virtual collaboration, virtual reality, automated equipment, remote operations centres and strategic partnerships. A synthesis of all these components creates a ænetwork effectÆ that can dramatically improve the overall effectiveness the entire operation. The concept of the Network Centric Mine borrows from a variety of industries, including defence, aerospace, aviation, petroleum, utilities and manufacturing. Central to the concept are improvements to the way we connect people, process, information and technology, resulting in a more highly collaborative business model, with roles and processes designed to take advantage of new technology. The components of the mining operation act as a connected network aimed at a common goal, regardless of the boundaries of organisation and location.The design of this new organisational ecosystem needs to take into account the recent advances that enable the æplug and playÆ integrated collaborative environment, including cloud computing, mobile devices and social networking, as well as advances in augmented reality, robotics, geo-location, digital labelling, simulation and analytics. However, the most consistent lesson from other industries is the need to properly enable the behaviour and process changes necessary for success.Benefits from adopting a network centric approach include the more effective use of scarce expertise, improved data and information analysis, reduced process variance, and more informed and faster decision-making. The future of mining will see more technology savvy workers who will drive the adoption of new processes. The operations will shift from a relatively static and disparate set of functions, to a digitally aware, dynamic, automated, integrated and interactive environment, with increased agility, lower operating costs, higher productivity and improved safety.CITATION:Farrelly, C T, Malherbe, G, Gonzalez, J, Bassan, J and Franklin, D C, 2012. The network centric mine, in Proceedings International Mine Management 2012, pp 143-160 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

The JORC Code contains a mandatory classification system for Mineral Resource and Ore Reserve estimates for public reporting. The classification is a statement of the Competent PersonÆs confidence in the estimate and an attempt to convey that confidence to the various users of the resource estimate. In general the classification process is either largely subjective, relying on the Competent PersonÆs experience, or relies on statistical measures derived from the estimation process, or is derived from an estimated level of confidence in the outcome. However, the statistical measures may not necessarily relate to the overall confidence in the resource or reserve which must take account of the confidence in the geological inputs to the estimation.In addition to the traditional deterministic interpretation and estimations adopted by geologists, semi-quantitative techniques are now available to improve the estimation of confidence while continuing to involve the Competent PersonÆs experience in the process. Methods for quantifying confidence in mineral resource estimates for advanced projects and operating mines have also been developed.Classification is undertaken primarily as a communication tool between the estimators and the other stakeholders in the process. A brief examination of the stakeholdersÆ requirements is included.

Sep 26, 2011

By W B. Edgar, S C. Dominy

High-nugget effect vein-gold systems are generally considered to be one of the most challenging of deposit types to evaluate and exploit. To potential investors and mining companies, they are viewed as high risk because of the associated uncertainties in the grade estimate and general paucity of Ore Reserves at production start-up. However, despite the well-known risks, these deposits often have a grade upside that makes them potentially attractive. The reporting of resource grade is of importance and perhaps even more so is the reporting of the associated uncertainty attached to the grade estimate. The use of the grade estimate supported by a grade range is recommended to achieve more complete and useful disclosure. The definition of the grade range can be somewhat subjective, ranging from opinion based estimates through to data-based estimates and geostatistical conditional simulation. Whichever method used, the over-riding issue must be the provision of enough data of appropriate quality and full disclosure to the public of relevant uncertainties.CITATION:Dominy, S C and Edgar, W B, 2012. Approaches to reporting grade uncertainty in high-nugget gold vein projects, in Proceedings Project Evaluation 2012 , pp 95-108 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

By C J. R Hart, J K. Mortensen

The distribution of mineral deposits within northwestern North America (Alaska, Yukon, and northern British Columbia) allows for an in-depth examination of the metallogenic patterns of a growing continental margin. A more complete understanding of the tectonic evolution of this part of the Pacific Rim, achieved over the last 15 to 20 years, now allows for the placement of ore systems into a well-defined plate tectonic framework. Ore deposits older than about 185 Ma represent hydrothermal systems that were active in the platform/shelf environment of ancestral North AmericaÆs miogeocline or hydrothermal systems developed in oceanic arcs and continental fragments more distal to the craton. These include important SEDEX, VMS, and pre-accretionary porphyry deposits. In contrast, most mineral deposits younger than about 185 Ma were formed within the growing Cordilleran orogen, as terranes were accreted to the continental margin during interactions between the North America and Pacific/Farallon/Kula plates. Such syn- to post-accretionary mineralised systems include many large lode gold and porphyry/skarn systems.

Jan 1, 1999

By W Russell, P Wighton, J Franke

Recent advances in ruggedised industrial control system technology and architecture in combination with latest technologies in the fast-evolving 3D LiDAR sensor sector becoming available have enabled the implementation of sophisticated automation algorithms for mining equipment such as bucket wheel reclaimers, as published by the authors in the peer reviewed AusIMM 2019 Iron Ore conference proceedings. This paper provides an overview of a second use case for such automation technology in bulk material ports integral to iron ore operations. The real-time 3D machine-vision based port automation system described in this paper was originally developed for the BHP-Mitsubishi Alliance’s (BMA) Hay Point port. The system has seen deployment at other major mining and general ports in Australia, such as at Dalrymple Bay Terminal (DBT) (shown in Figure 1) managed by Dalrymple Bay Infrastructure Management (DBIM), Hay Point, Queensland. It has the following use cases:

Nov 8, 2021

Open pit mining has considerable damaging effects on the environment of the mining region. These harmful influences have to be controlled during mining operation until mine closure. Different sections of mined land, such as; pit(s), waste dump(s), tailing pond(s), roads, areas for onsite facilities and free land zones which are not mined, have to be reclaimed through treatment of environmental pollution and implementation of a permanent post mining land use (PMLU) after mine closure. Implementation of a permanent optimal post mining land use (OPMLU) is one the most decisive criterion which effects on reclamation procedure, mine closure and their costs. Therefore to define ultimate pit limit (UPL), mine closure and reclamation costs should be entered in the calculation iterations same as the other variable costs of the projects. Estimation of closure and reclamation costs of a mining project is carried out based on the attained OPMLU and the specifications of the mine site. In this paper, a model is developed to provide OPMLU for pit area through fuzzy multi-attribute decision making (FMADM) technique. The model was implemented on a hypothetical copper mine in northwest of Iran as a case study. Lumber production was selected as OPMLU for the pit area. It is finally concluded that through the developed model, OPMLU for different sections of mined land in an open pit mine project is defined. Also closure and reclamation costs are estimated based on the defined OPMLU to achieve a more accurate UPL.

Dec 6, 2010