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Forty years ago Dr Pierre M Gy, a metallurgist, introduced variography as applied to monitoring a process. Consequently, his followers used the variogram to elaborate meaningful process control charts, especially since 1993. The name æChronostatisticsÆ was suggested several times by Gy as a logical name for this new science. The intent was to draw a parallel between the variogram identifying the variability components affecting a process parameter as a function of time, and the variogram used in geostatistics identifying the variability components of a given mineral content as a function of space. Heterogeneity problems encountered have indeed strong similarities. However, there is a fundamental difference. The variogram used in geostatistics is often stationary within a given type of mineralisation. While investigating a dynamic process through Chronostatistics, there is no such thing as a stationary variogram. Still, the evolving variogram provides essential information about subtle, often overlooked process difficulties. Chronostatistics is especially useful for management to take advantage of existing data that are often a forgotten source of valuable information to pinpoint recurring structural problems. The superiority of Chronostatistics over conventional statistical process control approaches is that it links observations to the inherent heterogeneity of materials under investigation, therefore to the sampling theory. Chronostatistics is like opening a new world to the metallurgist, making the process variability speak in a more comprehensive and in-depth way. Several case studies are presented to demonstrate the potency of this new science. For each of them, observations lead to solutions for continuous process improvement, therefore attractive economic opportunities. The philosophy is this: if a control chart shows a process is out of control, it must also suggest logical and pragmatic directions for solutions. The intent of this presentation is to vastly expand on these valuable, almost forgotten ideas.

Jan 1, 2006

By Magne L, Barria J, Castro O, Menacho J, Gonzalez GD

An extensive experimental campaign was developed in a continuous 6 x 2' (D x L) pilot scale SAG mill. The effect of the feed flow rate, feed solids concentration, ball filling fraction and feed size distribution, over the mill performance was investigated. The residence time distribution (RTD) for the fine material was measured in every test, in order to detect changes in the mixing characteristics of the mill under different operating conditions. Based on phenomenological considerations a state model of the SAG mill was developed, which independently incorporates mechanisms such as: grinding, mass transport and classification in the grate discharge. These can be parametrised using information and optimisation software. This comminution model extends the compensation condition, which is a conventional hypothesis for ball milling, to the semi-autogenous mill grinding. The mathematical analysis of this hypothesis, applied to SAG mills, allow the reduction of the number of parameters in the model, using the relationship Ki = (1-bii)Si, where b and S have the conventional meaning. Therefore, the distribution fracture matrix bij and the specific fracture rate SIE are grouped in just a single diagonal matrix Ki.

Jan 1, 1993

By T Leidich, M Van Zyl, H Lacy

Mining ‘as usual’, until the most recent decades has resulted in limited landform planning and a general lack of mine waste landform design. Material characterisation, mine planning and dedicated professionals undertaking these tasks were rarely available or in place at the majority of mines. This has led to landform instability, erosion, sediment and poor quality water emanating from mine landforms. In many cases rehabilitation and reclamation failed and these sites have ‘landform features’ that are difficult to relinquish or leave and have little or no apparent land use. In many cases mined landscapes around the world have resulted in a less functional and degraded environment, with deleterious impacts on surrounding ecosystems.This situation is now slowly being addressed, as global companies, academics and practitioners and their organisations have started to exploit the ideas from an integration of earth sciences and mining through the application of planning software dedicated to the design of landforms.This development has had its genesis primarily in the United States. We suggest that process has been driven, in recent decades, by the application of resources in response to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), (USA Congress 11 December 1980) and other mine reclamation legislation enacted by federal and states regulators in the USA. The combining impact has seen a huge transfer of capital back from the public purse and ‘potentially responsible parties’, into abandoned mines to affect control, remediation, and reclamation/rehabilitation of those mines.Given this investment in rehabilitation and reclamation, people engaging in the business of landform planning have had the opportunity to address landform reclamation of historic and active sites. The skills of engineers and scientists with improved technology, waste rock characterisation and modelling tools have been combined resulting in the evolution of landform design and in mine planning of active mines. This has delivered cost-effective, sustainable mine closure designs for over 30 years. Integration of mine design with an understanding of geomorphic principals and the natural landscape, coupled with waste and soil characterisation, yield a positive result. Recently work has been applied across large and small-scale projects by companies. As these processes develop, ideas and concepts are evolving that active mines, or mines in the early planning stages, could use to help reduce double handling, and in the long run reduce overall project and closure costs, more effectively attain the desired final land use, and enhance the industry’s reputation and licence to operate.CITATION:Leidich, T,?Lacy, H?and Van?Zyl,?M,?2014. Application of design concepts and engineering controls necessary to deliver well-designed and rehabilitated landforms, in Proceedings Life-of-Mine 2014 , pp 55–66 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By A Fareth

Constructed between 1885 and 1891, the New Croton Aqueduct (NCA) in New York State is a 50 km long (31 mi) brick-lined tunnel conveying water from the Croton watershed north of New York City to distribution systems in the Bronx and Manhattan. Except at two siphons, the aqueduct operates as an open channel conduit from the New Croton Reservoir downstream 39 km (25 mi) to the Jerome Park Reservoir in the Bronx. The remaining 11 km (6 mi) is operated as a pressurised conduit and includes a major siphon, of circular cross-section, under the Harlem River. The aqueduct has a flow capacity of approximately 1100 million litres of water per day (13 m3/s or 290 million gallons per day) and supplies on average ten per cent of New York CityÆs drinking water. The CityÆs water supply system is operated and maintained by the New York City Department of Environmental Protection (NYCDEP). This paper covers the work done during the three main stages of the program to rehabilitate the entire NCA: inspections, design and rehabilitation. It also includes some of the more interesting structural findings of the original construction as well as documents and drawings from the NYCDEP archives. The rehabilitation program has been underway in phases since 1993, with inspections scheduled to minimise outages, allowing this strategic aqueduct to remain in service during critical seasonal periods. The open channel flow section of the aqueduct in the north is horseshoe shaped, with inside dimensions of 4.1 m (13.6 ft) in width and 4 m (13.5 ft) in height. The pressurised section is 3.7 m (12.3 ft) in diameter, and includes a 90 m (330 ft) deep siphon under the Harlem River. A total of 163 million bricks were used in the construction, enough to build a 48 km (30 mi) wall around Manhattan Island, 3 m (10 ft) thick and 15 m (50 ft) high.Between 1993 and 1997 a series of in-tunnel investigations were performed in the open channel portion of the NCA, consisting of field inspection, non-destructive geophysical testing, and coring of the brick liner. Between November 2004 and September 2005, a major inspection program was conducted to assess the condition of the 11 km (6 mi) long pressurised section and all shafts, headhouses and blow-off structures along the entire 50 km (31 mi) alignment. Inspection methods included using an underwater remote operated vehicle (ROV) equipped with sonar and cameras to inspect the deep siphon, fibre optics examinations of probe holes drilled through and beyond the brick lining, and core holes and geophysical inspections to assess properties of the liner and behind-the-liner materials. A water pressure and test grouting program was conducted to assess methods and expected grout takes for the rehabilitation work in the pressurised sections. The rehabilitation program is anticipated to be completed in 2010.

Jan 1, 2008

By P J. Fairfield

"This paper reflects on the author’s experiences in undertaking mining studies and reviewing mining projects and technical reports, particularly over the past five years, and the impact of recent changes in reporting standards and listing requirements pertaining to mining-related evaluation and valuation exercises. It also discusses contemporary changes in the expectations of the investment community and the implications for the role of the technical specialist in providing advice to such stakeholders.Not for the first time in history, the resources industry has experienced a significant downturn after a period of strong, sustained growth in line with the traditional view of the cyclical nature of commodity markets. The resource industry is currently faced with capital austerity in the wake of projects ‘failing’ (not delivering to expectations). In response, the industry has experienced changes in investment behaviour (slowing of investment) and an increasing regulatory burden as stakeholders seek a greater understanding of mining project risks.This paper discusses this response and uses case studies to highlight the key learnings (perhaps re-learnt) by the industry. It also discusses the challenges faced by technical specialists in communicating the results of technical and valuation studies to the investment community.As investors seek to take advantage of the current stage in the investment cycle, the key challenge of the technical specialist is to effectively communicate the uncertainty in technical assumptions, risks and opportunities that drive project value.CITATION:Fairfield, P J, 2016. Managing expectations – from buyer beware to buyer be aware, in Proceedings Project Evaluation 2016, pp 66–74 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

By A T. Spathis, K E. Leslie, K R. Blay

Many open pit mining operations seek to control blasting-related movement of ore and waste to minimise loss and dilution. Tracking the movement of ore boundaries can result in the maximisation of ore recovery and minimisation of waste sent to the mill, thereby optimising the economic performance of the operation.A novel solution for tracking the ore–waste boundary location before and after a blast uses subsurface markers placed along the boundary with all measurements and scans conducted remotely from the blast block. Upon system activation, user-operated equipment on the surface determines the three-dimensional (3D) location of the subsurface markers.The patented system concept combines two electromagnetic mechanisms, magnetic positioning and radio frequency through-rock communications to enable remote battery-powered markers, buried within the rock to be accurately located in 3D space.Field trials at a quarry have demonstrated the system can comfortably handle over 100 subsurface markers with a complete scan, including set-up, taking less than an hour. Location accuracy for each marker in 3D space is better than 0.5 m at a range up to 50 m from the magnetic source, and the system has an overall operational range in excess of 75 m.CITATION:Blay, K R, Spathis, A T and Leslie, K E, 2015. A remote, rapid and accurate three-dimensional ore waste boundary tracking system, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 297–306 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

Analysis of Procedures and Drivers for Industrial Waste Management

Sep 13, 2010

In the geologically prospective nations which rim the Pacific Ocean, mineral deposits offer great potential to create wealth for social and economic development. The paper first examines the geological and economic attributes of potential mineral wealth based on current outlook assessment of all significant base metal deposits discovered to 1988 in two Pacific Rim nations - Australia and Canada . The variability of mineral wealth among the economic deposits evaluated and the major contribution of the few world-class discoveries to total mineral wealth are highlighted. Then, the essential but too often neglected linkage between the makeup of potential wealth and its actual realization is analysed. The impact of taxation and the role of exploration are crucial in this regard. Finally, the ingredients of exploration success, prerequisites for realizing the mineral wealth of nations, are examined.

Jan 1, 1995

By C Paoletti

About 15 years ago the debate on the reliability of sampling procedures for agricultural food and feed commodities was initiated by a few brave scientists who questioned the representativeness of what, at the time, were routine sampling procedures established exclusively on the basis of tradition and practical feasibility. Over time several national and international organisations contributed to the discussion, developing standards and publishing papers either to underline the fact that sampling is always a source of error, in itself, which cannot be overlooked, or to minimise the relevance of sampling on the basis of argumentations linked to time and money limitations. The latter dominated, but is nevertheless impossible to accept from both a scientific and a responsible management perspective. Here the author presents an historical overview of these past 15 years, illustrating the most controversial issues, reporting major achievements in food/feed sampling, highlighting milestones, as well as unresolved problems that still need the attention and contribution from the sampling community. The need to incorporate Theory of Sampling (TOS) into food/feed safety assessment (pre-market), as well as into food/feed safety monitoring (post-market) has recently been highlighted, and the practical applicability of TOS to base food/feed safety decisions on representative sampling, has been explored and documented via concrete examples of risk analysis in different areas of food/feed industrial production chains. Now it is time to move forward and ensure that TOS is fully integrated into the well-established Food and Agriculture Organization (FAO) / World Health Organization (WHO) risk assessment approach, in order to guarantee a transparent and correct universal frame for risk assessment and the subsequent management decision-making process. WCSB8 offers the ideal platform to explore the best way to do so, switching from a theoretical discussion of correct sampling principles for food and feed agricultural commodities to practical recommendations in the interest of consumers, worldwide. These 15 years have also been a personal journey of interesting dimensions, indeed a veritable roller-coaster ride in-and-out of the scientific, technological, industrial and (last but not least) regulatory worlds. The start was WCSB2 in 2004, when I flew to Australia to discover if in other areas sampling had been identified as an unavoidable issue and, if so, what the solution was. There, I found a good travel companion who today is still on my side, to assemble the puzzle and explore how to shape the future, to concretely answer to the 15 years’ quest for proper sampling in the assessment and monitoring of food/feed safety.CITATION:Paoletti, C, 2017. Assessing and monitoring food and feed safety – a 15 year quest for proper sampling, in Proceedings Eighth World Conference on Sampling and Blending , pp 39–44 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

To solve the mining safety and health needs of the future, access to, and sharing of, timely and relevant information will be crucial. The next generation of the Web will provide tools (RDF, OWL, SPARQL, etc) to define and link content for more effective discovery, integration, and reuse across applications and organisations. A recent Gartner Research Report (Finding and exploiting value in Semantic Web technologies on the web, May 2007) predicts these technologies will begin to coalesce in ten years. Implementing this Semantic Web requires structured web content described via metadata (information about information). If an industry or enterprise bases its metadata on a common vocabulary, it becomes possible to share and reuse information. The National Institute for Occupational Safety and HealthÆs (NIOSH) Mining web site provides access to more than 1500 NIOSH-developed publications, products, and topic pages on issues as diverse as ground control, respiratory diseases, and mine emergency management. As the site has grown, locating content has become increasingly difficult. To improve the searching process, a panel of internal experts representing all major research programs was established to develop a controlled vocabulary for indexing that content. The outcome is the NIOSH Mining Safety and Health Thesaurus, a faceted, hierarchical thesaurus containing hundreds of mining safety and health terms organised into 20 facets (eg diseases, injuries and disorders; hazardous events and exposures, equipment, engineering and administrative controls). One immediate goal of this project is to reduce the complexity of locating information on the NIOSH Mining web site by implementing metadata and faceted information retrieval techniques. Another goal is to stimulate discussion in the international mining community regarding developing metadata standards so the industry is ready to adopt future Semantic Web technologies to improve access to mining safety and health information.

Jan 1, 2008

By D J. Hill

"Mining companies routinely invest in improvements to their processing operations, but often these enhancements do not work to full effect.Improvements can be ineffectual because underlying process problems are not identified or prioritised for correction or repair.This is frequently because ‘black box’ solutions deployed to implement process control improvements typically rely on instrumentation to provide data for algorithms to work effectively, and these solutions are often ineffective or disabled at mineral processing sites.There are three key reasons they can fail to deliver: vital instrumentation is not calibrated or functioning as required basic process control and loop tuning was not implemented correctly or is in need of tuning there is an inability to support the ‘black box’ solutions on-site.Many of these problems can be overcome by implementing operational analytics that identify where problems are occurring and prioritise where improvements need to be made.Incorporating operational analytics into process improvement is not a new methodology. It is more a back-to-basics approach to make more efficient use of capital and systems already deployed.Data collection systems, such as the OSIsoft PI System, provide real-time and historical process information for process control experts to analyse and identify areas for improvement. However, most systems are not used effectively. With some simple enabling, data collection systems can provide evidence for prioritising investments in improvements and determining an investment’s effectiveness.MIPAC advocates that the initial step, with analytical evidence, is that clients review the control strategies and implement small influential instrument repairs/calibrations and operator training. This can significantly boost process productivity without the need to spend large sums of money on new capital or employing expensive, difficult to maintain ‘black box’ solutions.A simple Stage-Gate®-style approach ensures that small investments in evidence-based process improvements deliver significant benefits to mining operations.CITATION:Hill, D J, 2014. How to prioritise process improvements, in Proceedings 12th AusIMM Mill Operators’ Conference 2014, pp 307–314 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 1, 2014

By R Durchholz, A-J Heiertz, R Schmitz

Mining of lignite is the largest bulk materials handling activity in Europe. In order to mine this lignite, with an average calorific value of only a third of bituminous coal in an economical way, highly efficient opencast mining technology is mandatory. The total continuous mining of overburden and lignite was introduced more than 60 years ago and was subsequently developed stepwise into the largest mass transport system of the world. In 2011, the Inden Mine, one of three RWE Power mines, stripped 90 Mbcm of overburden to produce 22 Mt of lignite. In total, nearly 100 Mt of Lignite was produced from the three mines of RWE Power in Germany. Beside bucket wheel excavators (BWE), several high-performance in-pit crushing and conveying (IPCC) systems, which allow the adoption of continuous mining systems, even for typical shovel and truck (S&T) operations, are available today. RWE Power assists operators considering a change from the S&T to IPCC technology, both in the planning process involving large-scale belt conveyor systems and later with operational know how transfer. In a number of cases, the challenges associated with this system change have been addressed and solved successfully. One key challenge is managing the development of skills for operating the belt conveyor systems efficiently. This paper compares the effectiveness of S&T to different configurations of continuous mining operation for an up to 170 m deep mine with a total annual output of 117 Mbcm. From the mine operatorÆs point-of-view, the quantity and skill level of staffing required for operation and maintenance are discussed in detail. The main conclusion of this paper is the larger the operation becomes and the longer the mine life is, the earlier fully continuous mining systems should be planned and implemented.CITATION:Schmitz, R, Durchholz, R and Heiertz, A-J, 2012. Change challenges for large open pit mines, in Proceedings Eighth Open Pit OperatorsÆ Conference , pp 103-110 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 18, 2012

By D Clarke, I Minniakhmetov

This paper describes the application of the SBRE framework to model the Olympic Dam deposit, one of the largest copper and uranium deposits in the world. Geostatistical simulations are the best practice for quantifying uncertainty in the mineral value chain and estimating resources. However, these simulations are currently undertaken on an ad hoc basis in the mining industry due to the high requirements in computing resources and capabilities in advanced geostatistics. The SBRE project provides a standard framework to test, build, and run conditional simulation workflows, which has been applied to the Olympic Dam deposit. Conventional geostatistical methods face challenges when modelling the Olympic Dam deposit, such as non-stationarity, non-linear correlations, and a large number of grid blocks to simulate. To address these challenges, a combination of methods was used, including projection pursuit multivariate transform, trend-residual decorrelation, pluri-Gaussian simulations, and turning-bands simulations. Various tools and applications were used to build the model, including in-house developed applications, Autovariogram software (Varify), and the RMSP python library. All computations were accomplished on the AWS cloud using the EC2-Batch service. The final set of simulations was validated using various methods, such as grade-tonnage curves, histograms, swath plots, and variogram reproductions, as well as validation using historical samples back-testing. The study highlights the importance of an automated, modular, and scalable framework in the development of conditional simulation workflows and describes the learning gained from trials of different combinations of methods and software

May 24, 2023

By M Alston

Many organisations struggle to yield meaningful outcomes from incident investigations. This paper will demonstrate that we can discover systemic issues by rethinking the ‘Why’ and ‘How’ of investigations, fostering genuine risk reduction. Key points: 1. Shift from ‘prevent recurrence’ to ‘learn and reduce risk’: conventional investigations focus narrowly on recurrence prevention, resulting in narrowly focused investigations with limited ability to identify and reduce organisational risk. Redirecting our objective to learning and improvement opens avenues for broader risk mitigation. 2. Understanding daily work for risk insights: recognise that work is not always completed in full compliance with procedures. Workers will adapt how they complete tasks influenced by the conditions and management systems that exist every day. Understanding the conditions and systems affecting everyday work is vital for uncovering systemic risks. 3. Unearth systemic issues through in-depth exploration: many investigations address surface concerns such as lack of training, incorrect procedures, equipment not being maintained, and missing overarching organisational risks. Systemic, organisation-wide risks are not identified. To discover these systemic issues and create shared learnings, investigators must question management systems, including resourcing, planning and risk management. 4. Design actions for safe failure: common actions like discipline and training fall short and do not reduce risk. Resilience emerges from well-designed controls. Incorporate planning, better resources, interlocks, and guarding to bridge the gap between task execution and risk. 5. Investigation Reports as a Business Case: Investigation reports should not simply state historical information regarding an incident. They are to facilitate decision-making and be presented as a business case to drive change. Organisations can move beyond localised risk and ineffective administrative actions by changing investigation objectives and methods. They can facilitate learning, understand daily work intricacies, identify systemic issues, and enhance the capacity for safety, driving lasting risk reduction.

Apr 16, 2024

Mining had a very considerable effect on the country's development. The visual evidence remaining is an integral part of New Zealand history. Early mining for manganese and copper in the 1840s was succeeded by alluvial gold rushes. These gave way to hard rock extraction, hydraulic elevation and dredging. Coal mining dating from the 1850s was fairly widespread. Other minerals were obtained on a small scale. Manufacture of mining' machinery stimulated industrial engineering enterprises. Schools of mines played a significant part in advancing technical skills and several remain as museums. Surviving mine structures and site relics are part of the industrial heritage signifying the technological and economic development of a small isolated nation. Some of these are described. Identification, recording and preservation where practicable is advocated.

Jan 1, 1990

By S Hancock, B H. Brady, H Muhlhaus

The aims of this paper are to present the governing science, verify the performance and demonstrate the potential engineering applications of a computational simulator for in situ leach mining of non-ferrous minerals. Assuming that the target mineral is deposited either uniformly within rock matrixes (matrix-hosted) or on fracture walls (fracture-hosted), in situ leaching can be treated as reactive flow and transport in geological media (porous media for matrix-hosted ore deposits and fractured media for fracture-hosted ore deposits). Under this treatment, the processes of in situ leach mining for non-ferrous minerals can be quantified through several sets of equations and these coupled equations have been numerically solved. The computational simulator has been applied to the simulations of one-, two-, and three-dimensional in situ leaching cases. The computational simulator, together with laboratory and in situ leaching tests, can be used to:optimise the leaching chemistry; optimise the in situ scale mining operations; scale up the in situ scale test operation to a full-scale mining operation; and evaluate the post-mining environmental restoration plan.

Jan 1, 2000

By D Craw, G Eis

Late Cretaceous Blue Spur Conglomerate preserved as isolated remnants at Gabriels Gully, Weatherstones, Forsyth, Waitahuna Gully and Adams Flat was deposited during the intiation and early stages of extensional movement on the Tuapeka Fault zone at each locality. The deposits represent successive courses of a single fluvial system flowing across the Tuapeka Fault zone from the up-thrown (northeast) block. Each course, beginning with the channel at Gabriels Gully, was abandoned as a result of uplift-induced defeated antecedence in favour of a new course farther to the southeast around the southeast-propagating tip of the Tuapeka Fault zone. Schist and quartz in the conglomerate was derived ultimately from schistose rocks northeast of the Tuapeka Fault zone. Caples Terrane greywacke detritus in the middle and upper beds of the conglomerate was probably recycled from pre-existing sedimentary cover on the up-thrown block, following initiation of uplift on the Tuapeka Fault zone at each locality. Most of the gold is derived from vein sources in Otago Schist rocks to the north, and/or associated placers. Hydrothermal veins at Waipori, Hindon, Barewood, and Macraes are the most likely primary sources. There is no evidence to support previous interpretations of deposition by river systems flowing from the southwest, or axially along the Tuapeka Fault zone from northwest to southeast. High gold grades within Blue Spur Conglomerate should have a linear trend more or less similar to the orientation of the host channels, but are likely to drop off rapidly to the southwest. Extensions of the conglomerate-filled channels are unlikely to be preserved, but there is a strong probability that younger placers recycled from the former channels exist.

Jan 1, 1999

The sequences in alteration and mineralisation from five copper-gold porphyry systems (Taysan and Didipio, Philippines; Horse-Ivaal and Wafi River, PNG; and Goonumbla, Australia) and one gold-copper skarn system (Browns Creek, Australia) are documented in this paper. Alteration and mineralisation in all these systems reflect a common evolution from crystallisation of melts emplaced at shallow crustal levels (zoned potassic -> propylitic alteration), followed by exsolution of volatile-rich fluids from these melts (porphyry quartz ¦K-feldspar/biotite veins and local high temperature advanced argillic alteration), to a progressive cooling of the intrusion which results in associated retrograde alteration. Copper-gold mineralisation in all cases is almost exclusively restricted to the cooler retrograde events. The recognition of the temporal and spatial zonations in alteration and mineralisation in gold-copper porphyry systems has significant relevance in the interpretation of geophysical signatures, overprinting alteration, vein sequences and structural controls, and can lead to more focused and potentially more cost-effective exploration.

Jan 1, 1999

By N Jamson, T K. Rohde

The Mine is an underground zinc (Zn), lead (Pb) and silver (Ag) operation in central New South Wales (NSW). Broadly speaking the Mine has two domains that require rehabilitation, the mine industrial area (MIA) and the tailings storage facility (TSF). The MIA has been used for the handling and processing of ore and contains elevated sulfate, sulfide and metals (Pb, Zn). The TSF receives the by-products of processing, that is, potentially acid forming (PAF) tailings which also contain elevate sulfate, sulfide and metals. Typically, the rehabilitation of a TSF involves two controls. Firstly, controlling the potential for PAF tailings to form acid rock drainage (ARD) by limiting interaction with oxygen. Secondly, once the tailings are unsaturated, limiting interaction with water (usually as rainfall) to reduce the potential for ARD to be transported to the receiving environment. These two controls are often employed in the form of a cover.In semi-arid environments there are many Australian examples of covers that have been built to limit interactions of mine by-products with oxygen and water. Typically, the covers contain one or more layers and are built from soil and rock which may include run-of-mine rock. The Mine however has limited supplies of stockpiled soil; and run-of-mine rock is not generated in large volumes because it is used as backfill underground. A cover design strategy was developed to cater for these limiting factors. The strategy identified soil, ore and rock accretion (the accretion) below the MIA could be a potential source of borrow material for the cover. The purpose of this paper is to describe the cover design process, the method and results of large (2 m tall) column trials that were used as a cost-effective way to trial three cover options and finally, the paper describes the water balance that was developed from the column trial results and subsequent modelling using SVFlux.CITATION:Rohde, T K and Jamson, N, 2018. Making use of potentially contaminating mine waste in cover design, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 285–298 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

The long-term outlook Tor Australla's traditional mining products is for flat demand and continuing low prices. This has come about because of three far-reaching changes since earlier boom days: 1. Continuing declines in intensity of usage of basic mine products; 2. The failure of newer western and third world developing countries to realise growth expectations; and 3. Continued production pressure from third world countries (and first-world primary producers) in an effort to earn foreign exchange and rectify trade balances. These trends have led to a general situation of excess supply and weak demand. In this environment, the prerequisites for survival in the mining sector are first-class mines, modern and efficient production methods, low unit costs, aggressive marketing, and products with reasonable operating margins. Many of Australia's mines meet these prerequisites. Following the A$ depreciation and widespread unit cost reductions, most of these mines will be moderately profitable at current depressed commodity prices. They are well placed to benefit from price rises if these eventuate. A new generation of mines is concentrating on a more profitable product range (gold, diamonds, uranium, mineral sands). Australia's balance of trade remains firmly dependent on the primary mining and agricultural industries (Fig. 1). Despite optimistic talk of high-tech developments, tourism and a resurgence of manufacturing, these will remain a small component of Australia's export structure.

Jan 1, 1987