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As the theme of the conference is ære-discover Otago' from the minerals point of view, it is also timely. Of the eight million ounces of gold recorded produced from Otago, perhaps a quarter of this came from the goldfields of St Bathans, Vinegar Hill and Cambrians. The most notable among them was the Kildare Hill Mine, which is the so-called Blue Lake at St Bathans today. The bottom wash encountered in this mine contained the famous Kildare lead, which averaged 7 1/2 dwt to the dish, and is still one of the richest leads of alluvial gold known in the world. The richness of this lead, the best encountered in these gold fields, is otherwise stated to have yielded more than 42 ounces of gold to the cubic yard. It should be borne in mind that this equates to about $22 000 per cubic metre, in todayÆs values. I have been told by older residents of this district that in fact about 1 million ounces came out of the Kildare mine and associated workings. In todayÆs values, this would be about 530 million dollars worth of gold. The largest mines in the district were at Surface Hill, Kildare Hill, Nicholsons, Vinegar Hill, the Never Fail claim at Shepherds Flat nearby, and at Cambrians. It would appear that in almost every case, work stopped when the bottom wash progressed too deep down dip of the anticline hills on which it was initially found. The mining methods were sluicing and hydraulic elevating, and although the gold bearing ground did not stop, eventually it exceeded the ability of the mining methods then available years ago, to work it further. When it is realised that the previous mining has removed what is likely to be only a low percentage of the gold resources in these fields, a tantalising situation presents itself today in that mining technology now available will enable another cut to be taken off these fields. As in the past, I believe this will be million ounce plus and multi-million dollar scenarios, where the economic and social benefits will become widespread prizes.

Jan 1, 1992

Study on the Interaction Mechanism of Flotation Reagents and Rare-Earths-Bearing Phosphate Ore

Sep 13, 2010

The mercury, gold, silver, copper, lead and zinc values of soils over altered and mineralised rock were determined to establish the potential use of mercury as an indicator element in geochemical prospecting. The results are presented to show that mercury can be used successfully in prospecting for precious metal mineralization in the Thames-Waihi area.

Jan 1, 1979

Influence of Grinding Media on the Flotation of Carbonate Using Sodium Oleate as Collector

Sep 13, 2010

The Southwest Pacific is a region of active volcanism and geothermal systems. Only in New Zealand have the geothermal systems been exploited for electricity generation and industrial processing. At present, approximately 280 MWe of geothermal electricity is generated in New Zealand. A considerable amount of further exploration work is required before the total geothermal potential of the region can be assessed and before the significance of these resources can be judged against other local energy sources.

Jan 1, 1990

By R Stefansen

Stockyard operations are governed by the interaction between the different disciplines required to successfully schedule and control the supply chain of raw material through the stockyard in combination with the effectivity of the operation of the stockyard equipment. The system demonstrates a proven technology for implementing a centralised operation of full unmanned stockyard equipment, using a high precision absolute positioning system based on a Real-Time Kinematic (RTK) Global Navigation Satellite System (GNSS) receivers in combination with 3D rangefinders. The system implementation maps the surface profile of the stockyard inventory and allows in combination with proprietary algorithms for full operation of the stockyard machines without on-board operators. The operational impact of delayering the process by moving to a centralised operation is examined, together with the combined effect on the overall safety in the stockyard as a result of a change in reliance on operator skill dependencies. Average performance gains range from 10–20 per cent. The performance of the automation system is related to a consistency and reliability of uniform operation, which has an impact on the life expectancy and the effectiveness of the equipment. The effects of having instantaneous and correct information about the stockyard inventory volume measurement are investigated in relation towards spot price trading in current fast reacting markets.CITATION:Stefansen, R, 2017. Advanced automation for centralised stockyard operations, in Proceedings Iron Ore 2017, pp 105–110 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

Processing of Hard-to-Treat Copper Ore and Flotation Middlings Using Chemical Treatment

Sep 13, 2010

Improvement of Phosphate Ore Flotation Performance Through Sized Flotation

Sep 13, 2010

Lean Iron Ore Beneficiation in India

Sep 13, 2010

By P E. H Gregg, R B. Stewart

Restoration trials established in 1985 included a treatment where pasture seed was sown directly into fertilised tailings. After seven years, accumulated soil data was used to compare physical and chemical changes in the plots with the original tailings control area nearby.   A known amount of annual fertiliser additions over the seven year period allowed nutrient balances to be calculated. Losses of S and P were relatively high at 72% of applied S and 28% of applied P. Calculations show that at least 240 kg N/ha/yr was fixed by clovers and this is likely to be under-estimated given that the calculation did not allow for leaching losses.

Jan 1, 1993

Integrated Utilisation of Desulfurisation and Skimming Slag

Sep 13, 2010

Water rights and availability are extremely contentious issues in many mining regions around the world, in some instances leading to violent confrontation. This situation has the potential to only get worse because competition for 'scarce' water resources will increase with population growth. In this environment the dilemma facing the mining industry is how to generate confidence in developing a responsible, sustainable and transparent water management strategy that is recognised as such by all stakeholders. Whilst the water needs of the mining industry are minor compared to those of agriculture, an operating mine requires a relatively large quantity of water on a daily basis to carry out operations. Another contentious aspects of new mine development is the debate between all stakeholders on the amount and quality of water that a mine is able to discharge into the environment should this be required. There are a multitude of water resources available to the mining industry for operational needs however much of this water is saline and over the last two decades there has been a continual decline in water quality (ie salinity has increased). In today's world there are enormous internal and external pressures to reduce water consumption at a mine and/or alternatively use water not considered a resource by the local community (ie sewage, saline or salt water, desalinated water). Strategies to meet these objectives can be achieved by implementing good water management practices, by recycling process water, reducing water losses by evaporation and seepage (ie by increasing and improving dewatering practices) and employing new technologies such as dry stacking and dry processing. Recycled water, acid mine drainage water and water collected in the mining area have the potential to impact mineral processing performance, unless they are treated, because of the build up of mineral salts and decomposed chemical products in these types of waters. Besides this the regulatory requirements of any water discharged from a mine site (quantity and quality) have also become more stringent. For these reasons there is now some form of water treatment practiced at most mining operations around the world. This paper provides an overview of water stewardship undertaken in the mining industry over the last two decades and provides examples of water treatment practices that have recently been installed at mining operations that may be of interest to the reader.

Sep 13, 2010

The development of a robust belt sampling strategy and protocol inunderground gold mines is a fundamental requirement for effective grade quality control, ore accounting and mine-mill reconciliations. As part of the ore management system, a belt sampling system has been developed by the author, which is used to predict monthly gold grade and its error for underground/belt/mill reconciliation and grade control. This paper presents the step-by-step development of the belt samplingstrategy and sample preparation protocol at Target, an underground gold mine in South Africa. The belt sampling system at Target consists of an underground belt transporting run-of-mine material into an underground transfer point, a weightometer, a two stage crushing system, a tube splitter and a catchment device. The design allows run-of-mine ore on the belt to be sampled automatically by a go-belt sampler. GyÆs sampling theory of particulate materials forms the basicframework of the belt sampling strategy. The theory is used to quantify the optimum sample mass of broken material to be taken from the belt and to predict its reliability. It is also employed to determine the Fundamental Sampling Error (FSE), time interval between samples and particle size requirements of the final underground belt sample. Further, GyÆs sampling theory provides the means of analysing the crushing processes, splitting, segregation error, analytical variance, and the best sample preparation protocol. Although the belt sampling strategy developed in this study was forWitwaterstrand gold ore, the process is entirely general and may be very successfully used in any underground or surface mine.

Jan 1, 1999

By F Linares, B De Waele, K Bischoff, M Lacorde, G Loveday

Recent exploration has identified the presence of detrital iron deposits (DIDs) associated with banded iron formation (BIF) units in the north-west of the Congo Craton, Gabon. The regional geology comprises a complex of granitoids and gneisses assigned to the Archaean Chaillu Complex, within which older slivers of lower amphibolite-grade greenstones are preserved including muscovite-biotite-garnet-bearing felsic schist, amphibolite and BIF. These units are typically overlain by several metres of residuum comprising colluvium, eluvium and duricrust. The residuum is overlain by a regionally extensive loess cover from 2 m to 10 m thick.The DIDs occur within the weathered residuum as mostly unconsolidated gravels with lesser canga (CAN) duricrust draped over deeply weathered hematite. Head grades are in the range of 45 to 52 per cent Fe. Fresh BIF, located from 30 to 50 m below surface, is comprised of magnetite-quartz±amphibole. The detrital iron gravels are comprised of rod- and plate-shaped clasts of hematite (martite)-maghemite-goethite composition, in a ferruginous sand to clay-sized matrix. The DID form ridges and plateaus that coincide with magnetic highs defined using high-resolution ground magnetic surveys.The field relations and petrography indicate that the detrital iron accumulations are the result of weathering (including enrichment) and erosion of primary BIF. This includes removal of quartz, further oxidation and re-cementation of BIF to form ferruginous caprock. This cap and the in situ oxidised BIF were subsequently disaggregated and liberated, and further weathered to form the detrital iron accumulations.Metallurgical test work on bulk detrital iron samples has shown this material can be upgraded to lump and fines iron ore products with grades of 62 to 65 per cent Fe using simple scrubbing and wet screening, followed by dense media separation of the -1 mm fraction, with overall mass yields from 75 to 85 per cent. The test work indicates a high ratio of lump to fines products, sometimes exceeding 50:50.CITATION:De Waele, B, Lacorde, M, Bischoff, K, Loveday, G and Linares, F, 2017. Geological and metallurgical characteristics of banded iron formation associated detrital iron mineralisation in Central West Africa, in Proceedings Iron Ore 2017, pp 259–268 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By S Bluhm, LádeáOliveira, R Funnell

Taquari Vasouras potash mine (Vale Fertilizantes) has many interesting features including virgin rock temperatures of 50¦C at depths of 700 m. The mine has a relatively small shaft system with limited ventilation carrying capacity, which was not adequate to exploit the full extent of the deposit. This limitation was overcome by installing two large-scale recirculation systems with underground reconditioning centres. This paper describes this unique mine ventilation and cooling system and some of its history over the past two decades. The two controlled recirculation systems have been operating safely for some ten years and the use of large-scale recirculation has been a fundamental component in the increase of production and extending the mining further-and-further from the shaft centre. The recirculation systems have played a huge role in the mine profitability and comprehensively extending the mine life. The paper also discusses a number of novel design and operating features such as reverse running pumps for energy recovery. The underground chilled water system design required a number of special safety features in order to minimise the risk of water leakage since this could be catastrophic in a potash mine. This paper describes a good example of a mine in which the final ventilation and cooling system design ends up very different to what was envisaged at the greenfields stage.CITATION:Bluhm, S, Funnell, R and de Oliveira, L, 2013. Controlled recirculation and refrigeration at ValeÆs Taquari Potash Mine, in Proceedings The Australian Mine Ventilation Conference , pp 237-248 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By B Powell

Coastal acid sulfate soils (ASS) are wetland soils and unconsolidated sediments that contain iron sulfides which, when exposed to atmospheric oxygen in the presence of water, form sulfuric acid. ASS form in protected low energy environments such as barrier estuaries and coastal lakes and commonly occur in low lying coastal lands as Holocene marine muds and sands. When disturbed, the iron sulfides in these soils can oxidise and produce large volumes of sulfuric acid (essentially similar chemistry to acid rock drainage with mines) resulting in the subsequent release of toxic levels of iron, aluminium, manganese and possibly heavy metals. This results in detrimental effects on aquatic biota, plants, animals and steel/concrete structures and on human health in the surrounding environment. There are an estimated 2.3 million ha of ASS located along 6500 km of the Queensland coastline. In contrast to many mineral sulfides encountered in the mining industry, the pyrite crystals in ASS can be as small as 2 mm and commonly occur as framboids with extremely large surface area per unit mass, substantially increasing their reactivity if exposed to air (oxidation). Highly reactive iron monosulfides can also occur, particularly in drains and shallow lakes. Many coastal areas, where some 80 per cent of the population of Queensland reside, are coming under pressure for agricultural and urban development. Construction of canal estates, marinas, housing/industrial estates, roads, golf courses, aquaculture ponds, sand/gravel extraction and drainage for sugar cane can disturb ASS and release sulfuric acid, which may then drain into adjacent waterways with heavy rain. As development continues to encroach on coastal lowlands, the identification, quantification and management of ASS must be addressed as part of a commitment to the principles of Ecologically Sustainable Development (ESD). ASS can be successfully managed by adopting best practices and following guidelines, but government, community and industry must collaborate to raise awareness, avoid æhot spotsÆ and develop more cost-effective solutions. Scientists led the education and public awareness program showing infrastructure and environmental damages arising from ASS in Queensland. Using results from mapping and research, they convinced policy makers, industry and polititians to accept the need for legislation founded on good science. The resulting æState Planning Policy 2/02: Planning and Managing Development Involving Acid Sulfate SoilsÆ identifies the StateÆs interest in acid sulfate soils. The Queensland Government considers that development involving acid sulfate soils in low-lying coastal areas should be planned and managed to avoid potential adverse effects on the natural and built environment (including infrastructure) and human health. SPP 2/02 states where the policy applies and when a development application will trigger the policy. It can also be used to assist local governments in preparing their planning schemes under the æIntegrated Planning Act 1997Æ. The SPP 2/02 comes with a æState Planning Policy 2/02 GuidelineÆ to provide advice and technical information on interpreting and implementing the SPP 2/02. This guideline has legal status in assisting in the interpretation of SPP 2/02. Those seeking more detailed technical information can now also access the æSoil Management GuidelinesÆ and ASS æSampling GuidelineÆ, available from the Department of Natural Resources and Mines website. These are some of a series of chapters being developed for the æQueensland Acid Sulfate Soil Technical ManualÆ.

Jan 1, 2003

Natural Gas has been available in New Zealand for twenty years. During that time the gas share of the energy market has grown and now natural gas forms a significant part of New Zealand's energy scene, helping consumers to achieve a higher standard of living, and reducing dependence upon imported oil. Natural gas is now used for petrochemical manufacture and power generation in addition to direct supply to consumers. As concern for the environment continues to build, natural gas will have an increasingly important role to fill in these markets. This paper sets out the background to the development of natural gas in New Zealand and identifies the current markets. It then looks at those matters which are likely to influence the role of natural gas in the 1990s.

Jan 1, 1990

By D Craw, P Lindsay, B Peake

The geochemical properties of Kaiata Mudstone and Brunner Coal Measures are evaluated in order to determine their suitability for placement at the proposed Cypress and existing Stockton mines. Correct scheduling of this waste material is needed in order to prevent sulfide oxidation and the generation of acid rock drainage. The Kaiata Mudstone has both acid generating and acid neutralizing properties. Results from this study and previous research from Kingett Mitchell Ltd (2003), indicate that within the Kaiata Mudstone sulphur content decreases with distance away from the Brunner Coal Measure/Kaiata Mudstone contact, while calcium carbonate content increases; sulphur values range from 0.33 to 4.23 wt %; and the acid neutralizing capacity ranges from 0 to 10.4 wt %. The Brunner Coal Measures have a low capacity to neutralize acid and sulphur content is variable ranging from 0.25 to 3.5 wt %. Appropriate control measures are therefore needed for the Brunner Coal Measures and any Kaiata Mudstone within close proximity to its contact. Tests have been undertaken to develop a rapid field or laboratory procedure to define the potentially acid-forming from the non-acid-forming Kaiata material. Results indicate that paste pH, Net Acid Generation (NAG) and Carbonate Bomb tests are suitable. Results from the Carbonate Bomb Test show a strong relationship with the Acid Neutralizing Capacity (ANC) and the Net Acid Production Potential (NAPP), indicating that this method may efficiently determine non-acid forming material in the field within fifteen minutes. Ongoing research includes kinetic column and shake extraction tests. These tests will quantify what trace elements could be leached from the waste rock and provide information on the usefulness of alkaline producing products such as Bauxsol, Limestone and Cement Kiln Dust.

Jan 1, 2004

Copper Recovery from Printed Circuit Board by Carbonisation

Sep 13, 2010

On Kinetic Coupling in Meso-Scale Phenomena in Mineral Froth Flotation

Sep 13, 2010