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By M Vendrup, T C. Christensen, C Dube

The adsorptive and granulate forming MetClean™ process has been used at many locations in Northern Sweden, Norway, Denmark, France, Spain, Mongolia, Japan and Australia. It has been pilot tested and used in full scale treatment plants to remove metals from:mine watersleachate from solid waste in incineration flue gasleachate from fly ash damsleachate from landfill and waste ponds.The following paper provides details of pilot and plants tests on the effectiveness of MetClean™ in removing arsenic, antimony, barium, cadmium, copper, molybdenum, nickel, radium, uranium, vanadium and zinc. Results show that MetClean™ may reduce the concentration of these metals in treated effluent water to the one part per billion (ppb) range.The paper also finds that, for specific metals, the optimal adsorption condition depends on the:pH levelmolar relation between the specific targeted metal and the addition of iron (II) or manganese (II)type of oxidation agentssalinity levelpresence of other metals.The most effective pH level varies according to the targeted metal but falls within the pH 5 to pH 11 range. A compromise pH level may be set when more than one metal is targeted for removal at the same time and through only one process step. The removal efficiency of one or both metals may be affected by operating at a compromise rather than optimum pH level.The MetClean process generates non-hazardous solid waste. Waste can then be disposed of more easily than brine or sludge.CITATION:Christensen, T C, Vendrup, M and Dube, C, 2015. Pilot tests for heavy metals removal in mine water, in Proceedings MetPlant 2015, pp 404–415 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

How Particles Stick to Bubbles - The Influence of pH and Hydrophobicity in Flotation

Sep 13, 2010

By Adams R. W

A commercial scale strong acid leaching plant was commissioned at the Risdon plant of the Electrolytic Zinc Company of Australasia Limited, a member of the Pasminco group of companies, in February 1988. It was designed to upgrade the lead/silver residue product from 26% to 37% lead, thus improving the realised value and increasing overall zinc recovery. This in turn enables the lead smelter treating the lead residue to improve its productivity. The equipment consists of two 250m3 bricklined leach tanks and two 6.5m diameter stainless steel high rate thickeners operating with counter current washing at 95¦C and 120 g/L H2SO4. The present filtration and drying equipment is also being replaced. Two 35m2 squeeze action filter presses equipped with horizontal plates are being installed, together with ancillary drying equipment to ensure that the final product complies with the transportable moisture limit. The new filtration plant is due to be commissioned in mid-1989.

Jan 1, 1989

According to the data provided by the most recent European Survey on Working Conditions, roughly 25 per cent of the European working population is exposed to mechanical vibrations for no less than one quarter of the work shift duration, while around ten per cent are exposed for the entire work shift. The occupational exposure to whole-body vibration (WBV), in particular, represents a major health risk in mining, quarrying and civil excavation activities. In accordance with European Directive 2002/44/EC, the latest version of the Italian law on physical risks has recently confirmed the possibility of using relevant literature data on vibration magnitude in order to evaluate personal occupational exposure (vibration database or data provided by the manufacturer). Still the alternative option, based on field measurements, represents the most appropriated method of risk assessment, as it accounts for the actual operating condition at the workplace; actual operator and vehicle under investigation and specific working cycle. The article discusses the vibration measurements taken on a number of heavy machinery (excavators, loaders, trucks, dumpers, etc) employed for talc extraction in a mine located in Sardinia and the resulting personal exposure for the drivers. The assessment was carried out in accordance with the specifications of ISO 2631-1 and EN 14253.

Dec 6, 2010

By M A. Tuck

The dominant heat loads in a deep underground mine are the surrounding rock mass, autocompression and machinery. In addition heat can be contributed to by other sources. Many block cave, sublevel cave operations and coalmines utilise conveyors to transport broken rock out of mine, in some cases completely, in others in combination with other forms of transport. This broken rock can be loaded onto the conveyor at virgin rock temperature and can represent a major heat input to the ventilation airflow as it is transported out of the mine. The purpose of this paper is to review established knowledge regarding heat flow, from conveyed rock to determine the main factors influencing the heat flow and to develop a methodology for predicting heat flow from caved rock. The paper concludes with suggestions for further research in the area of conveyed rock heat transfer.CITATION:Tuck, T A, 2017. Accurately estimating heat load from conveyed rock, in Proceedings Australian Mine Vent Conference 2017, pp 225–230 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By G A. Challis, A B. Christiel

Microprobe analyses of electrum grains in some Hauraki Au-Ag deposits indicate that gold fineness is in the range of 500 - 800 (50 - 80 per cent Au), but for most deposits the range is usually narrower than this. The electrums contain minor amounts (<0.8 per cent) of copper, arsenic, antimony, mercury, iron, and sulphur. Platinum and palladium were analysed for but were not detected (detection limit 0.24 per cent for Pt or Pd). For some deposits (eg Waihi), the average fineness values for the analysed electrums correspond fairly well with the electrum fineness determined by assay during the historic mining operations.

Jan 1, 1992

By J Benn, V Kuznetsov, G Timms, A Spain

Earthen covers are now widely used in the mining industry to control the generation rate and/or release rate of low quality drainage from piles of sulfidic minewastes. Covers are usually designed to reduce the water infiltration rate and in some cases may also reduce the oxygen flux to the underlying sulfides. Engineered covers have only been used since the 1980s, however, and there is very little field data on their performance in the longer term. This lack of information has implications for the degree of confidence that can be placed on the predictions of the environmental impacts of sulfidic minewastes, for the acceptance of close-out criteria by regulatory authorities and for the financial liability of the mining industry. Covers were placed on sulfidic waste rock dumps at the abandoned Rum Jungle uranium mine during 1984 - 1985. These covers were designed to reduce the water infiltration to less than five per cent of incident rainfall by both water shedding and storage-release mechanisms. Regular monitoring by the Australian Nuclear Science and Technology Organisation (ANSTO) demonstrated that the covers performed better than the design criterion for around ten years, but infiltration rates have subsequently increased. There is a 66 per cent probability that the infiltration rate now exceeds five per cent of incident rainfall. The cover on the largest pile, WhiteÆs heap, was sampled in pits dug at eight locations. Sampling was carried out at the end of the monsoonal wet season and again at the end of the ædryÆ season. This, together with laboratory testing, enabled cover performance to be assessed against five criteria: design, construction, cover material characteristics, physico-chemical characteristics and biological characteristics. We are of the opinion that the design of the cover was suitable to achieve the objectives of stability, water shedding, storage-release, and provision of a substrate for vegetation growth. Over most of the surface of the heap, the construction of the covers, drains and erosion prevention structures was in accordance with design specifications. However, several small and localised bare patches on the upper surface of WhiteÆs heap coincide with a reduced cover thickness, which is likely to have been due to poor construction in those patches. The construction of covers on minewastes is dependent on an adequate source of material meeting design specifications. From our limited examination, it appears that there was shortage of material for each of the three zones û a lower impervious clay layer, the moisture storage-release layer and the upper erosion-resistant layer for vegetative growth. An indication of this was that the upper layers in some areas were observed to be thinner than specified. We are of the opinion that this shortage of suitable material has been responsible for some of the changes observed ten years after emplacement. Physical and geotechnical testing indicated that the cover materials no longer meet the original specifications. In particular, the permeability at the 8 locations was found to be greater than specified, by up to several orders of magnitude. The higher permeability may explain the higher observed rainfall infiltration and moisture content of the waste rock. This increased permeability appears to be due to a combination of biological and physical processes û galleries formed by termites and ants and an extensive system of shrinkage/desiccation cracks formed by the development of a polygonal blocky structure involving the entire lower clay layer. The desiccation cracks may fill with coarser illuviated materials and form a conduit through which roots access the underlying waste rock. Measurements were made of oxygen flux into the heap as cover layers were excavated in the pits. They indicated that the full cover currently reduces the oxygen flux to 20 - 23 per cent of that into bare waste and that this reduction seems to be proportional to the cover thickness. It was also found that the oxygen flux into the cover is about four times higher at the end of the dry season than at the end of the wet season and that the difference is due primarily to the difference in moisture content of the cover. Recommendations are made for the design and construction of covers.

Jan 1, 2003

By A G. L Pratt

Change and its relationship with the introduction of new technology is a constant of human history. The mining industry has many examples of this relationship. This record contrasts with its present day struggles to move beyond a public perception of being just ‘dirty, dumb and dangerous’. The drivers for the introduction of new technology are frequently listed as the occupational health and safety of people working in the mines, reductions in direct operating costs, and increases in productivity.This paper discusses the issues that a mining business needs to deal with to implement new technology with the best possible conditions for success. It comments on how the strategic and tactical components of technology planning relate to and interact with change management. The central discussion is directed at the role that people play in the successful implementation of new technology. The introduction of autonomous underground haulage equipment provides a background for the discussion of this topic.The paper uses case study references, equipment supplier information and research findings. The aim is to offer a high-level view of the issues a mine operator needs to consider when approaching the introduction of new technologies for underground mining.CITATION:Pratt, A G L, 2017. Technology change in underground mining – things to consider, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 103–114 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By K Lownie, R Sani, A Sianturi

Part of the PT Freeport Indonesia (PTFI) mine production is in the process of transitioning from the deep ore zone (DOZ) mine to the deep mill level zone (DMLZ) mine. The DMLZ mine is the next lift in the caving series and lies 500 m below the current DOZ footprint.In order to reduce the need for a very expensive additional ventilation system for the DMLZ mine, it was decided to reconfigure some infrastructure and upgrade the performance of the three existing DOZ mixed flow ventilation fans in situ, reducing the new fans required to two. This was far less costly than providing complete new installations.These fans are installed in individual underground chambers in DOZ mine exhaust drifts and connected to the DMLZ mine exhaust drifts system in 7 m × 7 m airways size, through sets of 6 m diameter by 500 m high raises.The upgrade process involved replacement of motors, fan shafts and bearings. The existing 1600 kW DOZ mixed flow fans are 3500 mm diameter and operate at a speed of 595 rev/min and were originally designed to deliver 390 m3/s at 3.3 kPa. Efficiency optimisation may be required at a later date.The upgraded DMLZ fans are required to deliver 425 m3/s at 3.7 kPa and it was necessary to increase in motor size and speed to 2200 kW at 710 rev/min. This paper will discuss the fan upgrade project and in particular the integration of an unusual ventilation system, which is based on the semi parallel operation of multiple large fans.CITATION:Sani, R, Sianturi, A and Lownie, K, 2017. Operation of deep mill level zone mixed flow fans after the first fan upgrade – a parallel fans case study, in Proceedings Australian Mine Vent Conference 2017, pp 285–292 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

Review on Some Research Methods of Mineral Crystal Chemistry and Computer Simulation on Flotation

Sep 13, 2010

By P Jones

Fosterville Gold Mine is an underground operation located approximately 20 km northeast of Bendigo and 170 km north of Melbourne. Fosterville is the most productive gold mine in Victoria, producing over 100 000 ounces of gold annually. Access to the underground is via two portals cut into previously mined open pits. Fosterville is 100 per cent owned and operated by Northgate Minerals, a gold and copper producer with mining operations, development projects and exploration properties in Canada and Australia. (Northgate Minerals Corporation, 2010).Underground operations commenced in 2006 with ore production focused on three orebodies – Phoenix, Ellesmere and Falcon. Primary ventilation to the existing operation is provided by wall mounted exhaust fans located underground. This system provides approximately 220 m3/s of primary ventilation to the operations with intake achieved through the portals. Exploration drilling during recent times has uncovered another lode, the Harrier orebody, located 2.2 km to the south of the existing workings. Due to the location of the new Harrier orebody, vent analysis revealed the requirement for a separate source of primary ventilation to service Harrier. Figure 1 shows a current underground long section and the location of Harrier in relation to the existing workings. A number of options were considered, including a parallel decline from one of the existing two portals, however, a 4 m diameter, 350 m deep surface ventilation shaft was selected as the most suitable and feasible option for the mine.In December 2009, geotechnical drilling commenced to determine the most suitable location for the shaft. Site locations were constrained by a number of factors including interaction with current and planned surface infrastructure as well as proximity to nearby community members at the southern end of the mining lease. Results from the geotechnical drilling indicated that the majority of the proposed shaft would be suitable for a 4 m raise bored shaft. However, the top 40 m of the proposed shaft were deemed unsuitable for raiseboring due to zones of weakness that would likely influence the stability of a 4 m diameter shaft (Robinson, 2010). Following independent geotechnical advice and input from experienced raiseboring contractors, it was decided to construct a 40 m presink prior to raiseboring activities.A crane mounted auger was chosen as the preferred method to construct the presink. This method differs substantially from traditional blind sinking methods which are highly labour intensive. The auger, or drill, is designed and built to be attached to a crane base using engineered pivoting cradles. The auger is suspended from the crane jib by pennant ropes attached to hydraulic rams. The auger applies rotation and axial loads to the drilling tools via a telescopic steel bar (Kelly Bar). Drill tools are attached to the bottom of the Kelly Bar and comprise an assortment of drilling buckets and reaming barrels. Drilling buckets cut in situ material and collect the spoil for removal and are used for the excavation of the ‘pilot hole’. Reaming barrels are used to expand the diameter of the excavation by directing cuttings into the pilot hole which are then removed by the drilling bucket. In June 2010, the presink was constructed utilising a crane mounted auger with support to the shaft walls applied via a remote fibrecrete unit. The excavation method involved cutting a series of smaller diameter holes (2.4 m wide) before reaming out to the final diameter (4.7 m wide) in 4 - 5 m vertical increments. Fibrecreting activities were carried out on the backshifts, to ensure the stability of the excavation and minimise interaction between the two units. The presink was completed on time and offered many advantages compared to traditional blind sinking methods, including safety, costs and timing. This paper will examine the benefits of this method as well as lessons learnt and future applications in the mining industry.

Mar 21, 2011

By K Osten, N Scagliotta, G Lane

Oceana Gold (New Zealand) Limited operates the Macraes Gold Mine near Dunedin on the South Island of New Zealand. The orebody is mineralogically complex and comparatively low grade requiring a series of unit processes and resulting in a relatively complex plant. As part of Oceana GoldÆs ongoing Business Improvement program, a concerted effort has been made to focus on operational efficiency. One aspect of this has been the efficient use of energy in the gold recovery process. A benchmarking process has been developed for the Macraes operation that includes comparison with other operating mines and theoretical design. Criteria for determining operational efficiency have been developed. While benchmarking is, in theory, a simple process, this paper looks at putting benchmarking into practice by catering for variability in ore and associate processing methods. The unit processes discussed include the comminution circuit, flotation plant, pressure oxidation plant and gold recovery circuits.

Jan 1, 2004

A tectonic interpretation of the Coromandel Peninsula which suggests that the basement underwent tensional collapse at its northern and southern ends would permit more ready penetration of late stage magmatic fluids. This hypothesis is consistent with regional trends of the chloride content of low grade geothermal waters and of the yield of gold and silver per unit weight of quartz worked. The consequences of such a model are that mercury should not only be a good pathfinder for Coromandel gold, but that it should be correlative with ratios of base metals high in the zoning or paragenetic sequences to those lower in the sequences. This is demonstrated successfully in an area of mineralisation in the southern Coromandel.

Jan 1, 1987

The Kalgoorlie Golden Mile is proposed as an Archaean volcanogenic-type deposit, modified and redistributed along later-developed structures. Rich pyritctelluride and Green Leader gold mineralization is associated with the end phase of basic volcanism and, in a general sense, is confined to a broad interface zone between the products of marine basic volcanism and later acid volcanism. There is virtualIy no ore associated with the main body of acid volcanics.Green Leader is the local name of a type of ore that occurs at some igneous rock contacts in association with graphitic sediments and layered acidic tuffs. It is characteristicalIy green, of various shades, and commonly yields very high gold assays, the reasons for which are not apparent in hand specimen.Carbonates, carbonaceous shales, tuffites, rich gold ores, and acid and intermediate dykes, alI indicating a common heritage, are features common to the main ore hosts, viz. the Paringa Basalt (Calc Schist) and theGolden Mile Dolerite ("Quartz Dolerite Greenstone").Several probably related fracture systems have reconstituted most, but not all, of the original deposits into a large number of steep tabular lodes.Includes two sets of discussions and comments from later Proceedings volumes.

Jan 1, 1974

Flow Sheet Development of Three Geographically Distinct Chromium-Bearing Ores

Sep 13, 2010

By B A. Mowat, T M. Leach

The Morobe Goldfield inPapua New Guinea has produced in excess of 120 tonnes of gold from predominantly alluvial sources. Hardrock gold has been mined historically at Wau (23 t) and Edie Creek (4 t) and geological resources have been established at Hidden Valley (78 t), Kerimenge (36 t) and Hamata (30 t).Numerous prospects have also been identified within the goldfield. Primary gold mineralisation is related to intrusion of dacitic to andesitic Edie Porphyry (2.4 to 3.8 Ma), often with associated diatremes, which have intruded along major regional structures. A full spectrum of deposit styles from proximal (mesothermal) to distal (epithermal) to the porphyry source is recognised. The transition between the proximal and distal styles is recognised both between deposits and within an individual deposit. The deposit styles should be termed porphyry related gold mineralisation rather than given the generic epithermal and mesothermal labels.   It is proposed that magmatic fluids which evolved from parent melts to the high level Edie porphyry stocks mixed with convecting meteoric fluids and were channelled along major structure and diatreme contacts. Proximal to the intrusives, gold mineralisation is associated with deposition of pyrite-hematite-quartz+/-magnetite-gold (Hamata) and pyritebasemetals-quartz-gold (Wau). The mineralising fluids were hot, and periodically saline due to pulses of magmatic fluid. Gold is non-refractory and occurs as 20 to 30 micron blebs within the pyrite.   More distal from the intrusives or under late cooler conditions, mixing of cool dilute meteoric and magmatic fluids resulted in gold deposition associated with arsenic rich pyrite-and arsenopyrite-mineralisation (Kerimenge, Hamata and Edie Creek). Gold is refractory and occurs within the sulfides either as sub-micron inclusion or within the lattice.   CO2 and H2S gases which evolved off the upwelling hydrothermal fluids as a result of boiling and pressure reductions, condensed within superficial groundwater and formed cool oxygenated bicarbonate fluids. These fluids percolated back down the structures depositing manganocarbonate in the upper parts of the hydrothermal system. At deeper levels in the system mixing of the descending bicarbonate fluid with upwelling mineralised fluids deposited manganocarbonate-quartz-sulfides nonrefractory gold (Hidden Valley, Wau and Edie Creek).   At Kerimenge the cool bicarbonate fluids have also quenched a late stage magmatic fluid rising along high permeability structures. The quenching has resulted in deposition of non-refractory gold mineralisation associated with hessite (Ag2Te)-tennantite-chalcopyrite deposition.   Within the Morobe Goldfield, a transition from deeper level pyrite-quartz+/-hematite-magnetite to intermediate level quartz sulfide and quartz-carbonate-sulfide deposition to upper level, massive manganocarbonate deposition is recognized. Gold mineralisation can occur within all levels up the system.

Jan 1, 1995

By J E. Lynch

The Weda Bay nickel and cobalt laterite deposits on Halmahera Island, Republic of Indonesia were first drilled in May 1996 by Strand Minerals Pte Ltd (Strand). Subsequent exploration has delineated four large laterite provinces, parts of which have been diamond drilled to outline an indicated nickel resource of 59.9 Mt of 1.51 per cent Ni and 0.09 per cent Co within a total indicated and inferred resource of 117 Mt of 1.36 per cent Ni and 0.12 per cent Co. The project is held as a Seventh Generation Contract of Work (COW) by PT Weda Bay Nickel, which is jointly owned by Strand (90 per cent) and PT Aneka Tambang (ten per cent). Strand is a wholly owned subsidiary of Weda Bay Minerals Inc, a company listed on the Toronto and Alberta Stock Exchanges in Canada. Halmahera is located in the north-eastern part of the Indonesian archipelago at the convergent junction of three major plates and is a region of considerable tectonic and geological complexity. The western arms of Halmahera form a classic volcanic island arc while the central region and eastern arms contain ophiolite complexes and interlayered sediments. The extensive areas of laterite discovered at Weda Bay have developed over serpentinised harzburgites and dunites of pre-Cretaceous age. Weathering of these rocks has produced laterite profiles that are enriched in nickel and cobalt. There are three economically mineralised laterite types, namely limonites, ferruginous saprolites and saprolites and all are amenable to rapid pressure acid leaching with recoveries of 98 per cent nickel and 94 per cent cobalt in less than 20 minutes.

Jan 1, 1999

The Australian Centre for Minesite Rehabilitation Research (ACMRR) was established through a mining industry initiative to meet the need of industry, governments and the community for sustainable systems for land affected by exploration, mining and mineral processing activities. The Centre, which is a consortium of the major groups associated with mining rehabilitation research in Australia, has a focus on both strategic research and technology transfer and combines a wide range of multidisciplinary skills covering engineering and the physical and biological sciences. The paper briefly describes the goals, structure, expertise and research and technology transfer activities of the Centre. The major research program areas of waste rock dump and final void stability, acid mine drainage, tailings disposal, and remediation of ecosystem reconstruction are described in the context of national priorities.

Jan 1, 1995

By T Wambeke, J Benndorf

A risk-robust development of a heavy mineral resource requires an assessment of the geological uncertainty and spatial variability of the key factors impacting the mining and processing operation. Attributes of interest are the total heavy mineral grade, the slime content and the amount of oversized particles. The modelling of a mineral sand deposit presents two main challenges. Firstly, the exact location of the geological boundaries are obscure due to the complex interaction of the deposit formation processes. Secondly, the properties of interest exhibit a rather complex transitional behaviour across the so-called soft boundaries. Traditionally, the modelling exercise is restricted to a consecutive stochastic simulation of distinct geological facies and orebody properties. This results in different zones separated by hard boundaries, ignoring the typical transitional behaviour.This contribution presents an alternative approach which models the entire sand body as a single domain while accounting for the complex trends present. Error curves are used to infer covariance model parameters without the need of a prior removal of the trend. The principle is based on minimising the differences between empirical and theoretical errors resulting from two methods of prediction calculated for different rings of influence. The added value results from the unambiguous decomposition of the spatial variation into a deterministic trend and a stochastic residual. The trend model neither overfits nor underfits the data. The calculated residuals are thus unbiased and the uncertainty can be correctly assessed.The effort results in a characterisation of the resource uncertainty which provides a more realistic image of the spatial variability of the key properties in and across the geological domains of an existing heavy mineral sand deposit.CITATION:Wambeke, T and Benndorf, J, 2014. Optimal inference of modelling parameters to simulate complex trends across soft boundaries – a case study in heavy mineral sands, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 73–84 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By N Guresin, A Cooper, L Lorenzen, H Muller, S C. Dominy

Sampling and metallurgical test work during various phases of engineering?studies?is of?paramount importance for a robust processing plant design. When developing a process flow sheet, risks in achieving desirable financial outcomes are minimised by ensuring appropriate sampling and adequate metallurgical test work supports the engineering and cost estimation at each phase of project development.The quality and type of samples used for metallurgical test work are just as important as the metallurgical test work itself. The key characteristic required of any sample is that it represents some defined portion of a mineral deposit. Representivity should take into account the spatial orientation, lithology, alteration, degree of oxidation, mineralogy and competency of the ore such as hardness and abrasiveness. Statistically representative sampling procedures and an appropriate metallurgical test work program should be designed to bring metallurgical understanding up to feasibility study standard and to give a basis for process plant design.Snowden has observed that the quality of sampling and quantity of metallurgical test work carried out during the various phases of engineering studies are often insufficient to truly support a robust plant design. Some designs are often the result of the plant design based on benchmarks of apparently similar orebodies or buoyant metal prices supporting cash flows until rectifications can be implemented.The paper will discuss important aspects of sampling and test work required for engineering studies in designing process plants based on industrial case studies.CITATION:Guresin, N, Lorenzen, L, Dominy, S C, Muller, H and Cooper, A, 2012. Importance of effective sampling and test work protocols for process plant design, in Proceedings Sampling 2012 , pp 95-108 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 21, 2012