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An important consideration in any mining operation is waste disposal management. Tailings management at Macraes gold mine allows for the disposal of tailings into fully engineered embankment dams and overburden material to be incorporated as construction material into those embankment dams. This paper outlines the current tailings management practices.

Jan 1, 1992

By A H. Clemens, T A. Moore

This paper discusses a number of technical issues related to marketing coal. It outlines how the results of research undertaken in New Zealand and overseas can help producers address a range of technical factors that impact on production costs and marketability. The paper also discusses trends in coal utilisation for power generation and how new technologies may require coal with different characteristics. Research and development into options for CO2 sequestration are discussed including carbon storage in forests, and removal of CO2 from flue or fuel gas in power stations, and its disposal.

Jan 1, 1997

Effect of Anionic Surfactant on Silica Particle Attachment at the Oil-Water Interface Controlling particle attachment is crucial where powdered solids come into contact with oil and water. Particles are trapped in a deep energy well at the oil-water interface, stabilising emulsions. Here it is shown that adding anionic surfactant causes dramatic changes to the bulk and interfacial structure of silica particle-stabilised oil-in-water emulsions. Exposing particle-stabilised drops to surfactant concentrations above the critical micelle concentration enhances the rate and extent of creaming and flocculation. Mixing particle-stabilised emulsions with surfactant solutions causes drop fragmentation. As the surfactant concentration increases, the average drop size decreases and particles are displaced from the interface during the mixing process.

Sep 13, 2010

By J P. Clark

Industrial minerals contribute about 50% of the NZ$1.2 billion generated annually by the minerals industry in New Zealand. The value is supplemented by a further NZ$500 million of minerals imported to supply our vital agricultural and industrial activity. As globalisation of the world's economy precedes, sources of minerals are being processed by fewer companies giving an ever-increasing control over global markets. If only to protect its primary production New Zealand needs to aggressively develop its mineral resources. The successful development of a deposit requires identification of the preferred market. While low-value aggregates dominate New Zealand industrial mineral production it is more specialised minerals supplied to the manufacturing and industrial sectors that provide more value per tonne. Minerals that have highly desirable intrinsic properties, or through value-added processing provide desirable properties, have the ability to fill niche markets both locally and overseas. Research and development towards enhancement or creation of desirable mineral properties could benefit New Zealand with both increased mineral potential and export of technological information. But, it is nearly always the market not the resource that dictates the viability of an industrial mineral and, with the globalisation of industrial mineral markets resulting in fewer but larger companies, any supplier must be ready to explore niche markets in order to compete on a more global basis.

Jan 1, 2000

By A Kurniawan, A Sjadat and M Akhasyah

PT Freeport Indonesia’s Deep Ore Zone (DOZ) is a block cave mining operation that has been in production for 15 years. DOZ is located approximately 900 m below surface and has an average production rate of more than 5000 t/d. The footprint of the extraction level will ultimately be 900 m long and average more than 200 m wide. The undercut level is located 20 m above the extraction level.While developing Panel 1K on the northern portion of the extraction level, a major geotechnical problem was encountered when there was a change in lithology and an associated fault intersection. A large collapse of the hanging wall of the extraction level drifts occurred in the area of the fault intersection between February and March 2011. This was followed by a collapse of one of the undercut level drifts directly above the extraction level in May 2011.It was suggested that the best approach to mitigate risk during rehabilitation was to systematically open up the failed area under the protection of a steel set support system. To achieve this, approximately 60 t of grout was injected from the undercut level to fill the voids created when the rock mass between the two levels failed. A ground penetrating radar system was used to survey the condition of the rock mass between the two levels before and after the injection of grout. After the grout injection phase was completed to a satisfactory level of confidence, rehabilitation activities started on the extraction level by taking out the now consolidated material from inside the drift in 2 m advances from under steel sets initially constructed in secured ground.Controlled blasting was the key aspect to the success of the initiative to open up just enough of the drift to systematically support the rock mass before the next set was installed. The systematic support consisted of in-cycle shotcrete sprayed over mesh pinned to the exposed rock, as effectively as possible, with splitsets before spiling the next advance’s protection canopy with rebar. Once secure, a combination of steel set and pumped concrete was installed as the final support. This final support provided a safe platform to repeat the process until the failed zone was safely traversed.CITATION:Kurniawan, A, Sjadat, A and Akhasyah, M, 2016. Rehabilitation of the collapsed panel 1K north in the Deep Ore Zone block cave mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 763–768 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By A Hekmat, M Fuentes, F Armijo, R Castro, F Rodriguez

Interpreting the behaviour of granular material and simulating the gravity flow are complex processes in cave mining methods. In this paper, a new Cellular Automata based code – FlowSim – is used as a flexible tool to simulate the gravity flow and subsidence zone in block caving mines. The simulation results of the gravity flow model in a real scaled mine as well as a scaled physical model are presented in this study. In this research, FlowSim was first calibrated at a mine, based on the information obtained from smart markers. These markers were located in five points of the second block of the Esmeralda sector, at the El Teniente copper mine, Codelco, Chile. The calibration was performed with the objective of reducing the discrepancy between the extraction zone defined by markers in the mine and FlowSim outputs. Regarding the mine data, FlowSim was calibrated with the minimum error of ten per cent between real and simulated results. Then, the calibrated FlowSim model was used to simulate the flow behaviour of a scaled physical model. This model was constructed in the Block Caving Laboratory of the University of Chile to scale down the same block of the Esmeralda sector with the scale of 1:200. The FlowSim outputs show that this software enables the simulation of the gravity flow of the scaled model with less than five per cent discrepancy in grade and dilution entry to the drawpoints. According to the obtained results, this paper recommends FlowSim as an appropriate tool which can improve the design of production level in block caving and can enhance the prediction of the subsidence zone and dilution entry.CITATION:Castro, R, Hekmat, A, Fuentes, M, Armijo, F and Rodriguez, F, 2016. FlowSim – a versatile flow simulation tool to quantify extraction and design alternatives for block caving, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 645–652 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By R Harding, T Hunt

For the past 120 years, Portland cement manufacture has been undertaken on the shores of the Whangarei Harbour in northern New Zealand. Through a serendipitous conjunction of geo-chemistry, the argillaceous marl found on Limestone Island in the harbour and Tikorangi Hill provides a perfect mix of the various elements required for strong and durable cement. Golden Bay Cement, and its predecessors, have been the guardians and managers of the use of these minerals. As the demands of the concrete industry have increased, so have the needs of the manufacturing process. Careful mapping of the resource at both Portland and Wilsonville Quarries has been undertaken. This has allowed the Company to change the Quarry operation from a purely volume basis to one of selection and blending of constituent minerals. Within the manufacturing process, change has also been introduced. Analytical techniques, using x-ray fluorescence spectrometry, microscopy and the application of modem data collation, has allowed fine tuning of the process. The Company now produces an increasing diverse range of products for both the domestic New Zealand market and exports to various South Pacific countries. This paper discusses the processing of limestone and æcement rockÆ into cement clinker, an intermediate synthetic mineral ground into cement. It examines control and blending regimes, and some methods used in determining process efficiency. An important technique ærediscoveredÆ has been the application of microscopy to clinker.  Examination of the major silicate minerals enables interpretation of the kiln processing and feedback to process operators. It also enables a prediction of indicated performance when ground into cement. Examples this paper give an insight into the use of minerals from Northland in some of the more important construction projects in modem New Zealand.

Jan 1, 1999

Python Underground Processing Plant Critical Design The use of continuous gravity recovery in combination with a controlled breakage fine crushing and screening system followed by flash flotation has been incorporated into the Python processing plant. This provides miners with a flexible, robust, low cost, low energy pre-concentration process for the recovery of gold and/or heavy minerals. The Python plant incorporates fine crushing utilizing either High Pressure Grinding Rolls or Vertical Shaft Impactors in combination with the InLine Pressure Jig and Flash Flotation to continuously liberate and recover the valuable minerals. The use of these technologies has enabled a narrow, transportable pre-concentration plant to be produced which can easily be installed and operated in underground drifts and tunnels.

Sep 13, 2010

By D Symonds, S S. Kanchibotla, L Kennelly, G McNamara, J Gaunt, B Adiyansyah

Ban Houayxai is a gold-silver mine operated by Phu Bia Mining Limited in Laos since 2012. The first two years of operation processed predominately soft oxidised ore but subsequent years were expected to process more fresh hard ore. Fragmentation of the fresh primary ores was also expected to be much coarser than for the soft oxide ores. This coarser and harder ore is expected to significantly reduce mill throughput and mining productivity. The Ban Houayxai management realised the potential downside risk when processing fresh harder ores and implemented a blast optimisation project to deliver finer fresh ore to the mill without unduly increasing blast induced dilution and damage.JKTech and the Ban Houayxai drill and blast team began a joint blast optimisation project in April 2013 to achieve finer fragmentation from fresh ores. This was achieved by modifying the bench geometry, blast patterns and applying exceptionally high levels of quality control during implementation. Blast induced ore loss and dilution was controlled by adjusting the ore blocks for blast movement. Finer fragmentation from these modified designs improved mill throughput for the hard fresh ore by 46 per cent above design on average. These new practices have been embedded in site operating procedures and have provided a quick reference ‘cookbook’ document for the engineers.CITATION:Gaunt, J, Symonds, D, McNamara, G, Adiyansyah, B, Kennelly, L, Sellers, E J and Kanchibotla, S S, 2015. Optimisation of drill and blast for mill throughput improvement at Ban Houayxai Mine, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 307–314 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

Selective Recovery of Platinum from Cobalt-Rich Crust

Sep 13, 2010

By D J. Robinson, L L. Kuhar

"Regardless of orebody value, at some stage, the pit will reach a depth where the reward for mining wider and/or deeper is not justified by the anticipated returns. ‘Last-blast’ strategies may help to some degree in recovering additional quantities of the resource but when a pit remains, there is often significant value left in the ground. In addition, in many cases, one or many good reasons may dictate why going underground and pursuing the orebody below the pit is also not justifiable. Whereas the company can hopefully move on to other more prospective parts of the orebody, the remaining options for the pit are usually very limited. Typically the pit is either held for potentially more favourable future pit expansion opportunities or it could be used for an alternative purpose, such as tailings or waste storage. This paper will present an alternative option that involves the direct extraction of values using in situ recovery (ISR) methods to recover additional value metals from the walls and/or floor of the pit. ISR involves circulating a fluid through the remaining orebody, solubilising the target metal and subsequently returning the solution to the surface for metal recovery. ISR is not the panacea to all but it has been employed selectively in the minerals industry for some time and the production of metals, such as uranium, rely heavily on this approach. ISR is not yet considered by many operators as an approach to compete with open pit or underground mining, largely because of the perceived limitations of this approach and the perceptions of risk. Rapid recent development of tools and enabling technologies relevant to ISR have made us reconsider the most economic approach to extracting many other metals from known mineral systems, even those currently listed as subeconomic. We suggest that ISR has the potential to make mine operators rethink the end of the pit life and adopt an innovative ISR approach to work toward a more complete recovery of value metals from existing pits.Citation:Kuhar, L L and Robinson, D J, 2016. In-pit In Situ Recovery - a New Approach That May Allow for Increased Value Extraction before Pit Closure, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 275–283 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

Validation of the JKMRC Rotary Breakage Tester (JKRBT) Ore Breakage Characterisation Device

Sep 13, 2010

By E J. B van Etten

This paper reports on the results of several years of monitoring rehabilitation at a silica sand mine on the Swan Coastal Plain, south of Perth. Mining here occurs below the regional watertable and leaves a post-mine landscape of dredge pond voids (pit lakes) with surrounding battered slopes. The restoration we recommended was to develop the pit lakes as wetlands of regional analogue and value. Several different restoration techniques have been applied to re-vegetate pit lake slopes over many years which have enabled an evaluation of reasons for success/failure of different restoration approaches. Learning acquired clearly showed the benefits of using fresh topsoil for restoration over topsoil that has been stockpiled for several years. Most topsoil used in restoration was from seasonal wetlands and consequently restoration was most successful in the riparian zone from the edge of pit lakes to about 2 m vertically above the water table. Topsoil restored areas above this level remained poor in plant species and cover. Conversely, remedial seeding/planting proved largely unsuccessful. Permanently and seasonally flooded pit lake margins recolonised relatively quickly and successfully with native sedges and rushes. Development of rehabilitated upper slope plant communities over time was evident with loss of typical wetland species and greater growth and survivorship of upland and dampland plant species on mid to upper rehabilitated slopes. Plant communities of lower slopes showed a converse pattern of development, with a shift towards a more typical wetland composition. We believe matching topsoil to site and development of topographic profiles similar to natural wetlands of the region are the keys to optimising restoration success of sand mines with shallow water tables.

Oct 5, 2011

By G Sparrow

The Murray Basin is being heralded as the next major mineral sands province in Australia. Already exploration programs have delineated extensive commercial deposits and several companies are progressing with plans to produce zircon, rutile and ilmenite in the Basin. As these deposits are developed consideration will need to be given to several key issues of the Murray Darling Basin; the availability of fresh water and management of salinity in the area being two of them. In this paper ideas being developed in CSIRO that link the processing of mineral sands with the salinity problem in the Basin are presented. The proposal presented here is to process saline water to produce industrial minerals with large volume applications and to produce value-added products from the mineral sands in the Basin using reagents produced from the saline waters. Processes to produce titania pigment and zirconia consume chlorine, caustic soda, soda ash and hydrochloric acid, all derivatives of salt (sodium chloride). There may be a good economic incentive if these processing plants were located in the close vicinity of each other.

Jan 1, 2001

The need for the hydraulic transportation of coal in the New South Wales coal industry, both from the coal face to the surface and from the coal mine to the consumer or the port for export, is explained. Details of research projects currently in progress and involving the hydraulic transportation of New South Wales coals are given together with information on the hydraulic transportation of coal in the United States of America. The potential of hydraulic transportation as a viable alternative to the proposed expansion and upgrading of the New South Wales railway system to meet the projected New South Wales coal production to the year 2000 is described.

Jan 1, 1980

By E Beltran, S Ngunz, F Orrante, F van Zyl, M Westcott

"The primary control objective of the project is to achieve milling optimisation by ensuring that the energy available for rock breakage is used as efficiently as possible. This is achieved by increasing the level of mill filing until a process constraint is reached. Stable operation against this limiting constraint is then maintained to ensure long-term optimised operation.Semi-autogenous grinding (SAG) mill control optimisation presents a number of challenges. SAG mills have multiple inputs that are used to control multiple outputs (MIMO process). Secondly, the SAG mill loading process is a ‘high inertia’ process that can be approximated as an integrating process. This means that it is open-loop unstable. The hybrid control strategy presented implements an advanced ‘load stabiliser’, which transforms this integrator process into a more manageable first order process, which can be steered stably against the constraints. This SGS hybrid Expert control strategy implemented on both SAG mills at the Porgera concentrator therefore consists of two integrated parts responsible for:stabilising the mill load to a targetdriving the mill load target to the maximum determined by the process constraints (eg maximum power draw) to maximise efficiency and throughput. A comparative study is done between the operation of the plant for a period of a month before and a month after the implementation of this strategy. The results indicated a significant improvement in the SAG mills’ stability and operation as well as a reduction of overload situations leading to a loss of throughput.Citation:Ngunz, S, van Zyl, F, Orrante, F, Beltran, E, Westcott, M and Wilson, S, 2016. Simplified Hybrid Semi-autogenous Grinding Mill Control - Explanation and Practical Results at the Porgera Concentrator, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 313–320 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By S C. Dominy

This contribution examines the effect of feedstock sampling before the sorting stage of polyethylene terephtalate (PET) bottle recycling. Batches of waste PET bottles may contain non-PET bottles which need to be removed by sorting. Any residual presence of PVC is detrimental for the quality of products manufactured from recycled PET. The maximum tolerated concentration of PVC in cleaned PET is extremely low, which places high demands on the recovery of PVC achieved by sorting. To be confident of attaining the desired PET quality after sorting, acceptance sampling of truckloads of PET bottles may take place prior to sorting. It is shown that accounting for sampling uncertainty requires that the sorting process achieves a consistently high recovery of PVC bottles.CITATION:Glass, H J and Dominy, S C, 2017. Plastics recycling and sampling, in Proceedings Eighth World Conference on Sampling and Blending , pp 129–134 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

I want to explore whether it is valid or even useful to talk about sustainable corporations. After 20 years of focus on sustainable development, the concept of a sustainable corporation is not particularly helpful and it may in fact be profoundly misleading. Why? û because it obscures the need for corporations to be recognised as part of a sustainable society, rather than achieving some kind of corporate nirvana divorced from the social, political and environmental reality. It is more helpful to ask whether corporations are ready to recognise that they are one player among many within society û with the demands this would place on them in terms of transparency, accountability and social responsibility. The achievement of sustainable development has become the new corporate orthodoxy of many large corporations. It has become a clichT to argue that corporations must become æsustainableÆ. The achievement of æsustainabilityÆ is encouraged, as the ultimate step in some form of corporate evolution. We are failing to recognise that sustainability a process û not an end in itself. An enormous array of instruments is being developed to measure when sustainability is or is not being achieved. For example, corporate reporting has burgeoned into an art form, which describes æsustainabilityÆ in a variety of ways. There is no external standard applied to such reporting. These descriptions are quite partial and often place the best possible gloss on the companyÆs activities. I have become increasingly uneasy about this rhetoric and this paper has allowed me the luxury of sorting out my unease. I will discuss, largely in the Australian context, the current debate and literature and describe the way some global mining corporations are dealing with these questions, and finally, offer some suggestions which might be helpful at the operational level.

Jan 1, 2002

By C J. Greet

Oil can enter a flotation circuit from a number of sources (for example, from mining equipment, oil leaks from the grinding equipment and coatings on the grinding media, but to name a few). Folklore generally states that any oil that contaminates the ore entering the flotation circuit is considered to have a negative impact on flotation. That is, a loss in concentrate grade and recovery.This represents a dilemma for some grinding media suppliers, who use a variety of quenching medium (air, polymer, oil or water) to achieve the desired physical properties of the ball. In the case of high chrome grinding media it is necessary, in some instances, to quench in oil to give the ball the right degree of toughness, which invariably leads to these balls having a thin film of oil on their surface. Once the grinding media arrives on site and site personnel recognise that the balls are “covered” in oil, they generally insist that the oil will have a deleterious impact on flotation performance.Obviously, any supplier “worth their salt” would take remedial action at the point of manufacture to minimise this problem. However, does quenching oil actually present a significant “threat” to the flotation process? This paper provides both laboratory and plant data describing the effect quenching oil has on the flotation of copper sulphide ore, with surprising results!

Aug 8, 2011

In coal mining, geophysical techniques have an established application in determining the location of seam boundaries ahead of the face so that underground mines can be planned to avoid any geological structures that might disrupt production. Geophysics can also be used in geotechnical studies to determine the in situ properties of the rock mass and the response of the rock mass to the mining. The use of geophysical logs and microseismic monitoring in these geotechnical applications are discussed in this paper.

Jan 1, 2002