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By F H. Henrfquez, A G. Oroz

Design and operating conditions of large size mechanical flotation cells were evaluated by comparing them with actual operating conditions in a plant. The objective was to determine the time scale-up factor, typically based on empirical rules. Experiments were conducted on the rougher flotation circuit at Minera Escondida Ltd. The circuit consisted of self-aerated mechanical cells of 160 m3, arranged in six parallel banks with nine cells each. The rougher circuit flotation kinetics were evaluated from direct sampling and local mass balances around each cell of the bank. Adjusted overall mass balances were also developed. This information was used to fit different kinetic flotation models, and it was found that the rectangular distribution function was the most appropriate to describe the distributed rate constant for industrial operation. Then, a rougher flotation simulator was developed to describe the actual operation in terms of the operating variables (mass flowrate, solid percentage, feed grade) and the actual volumetric flowrate entering to each cell. In this study feed pulp samples were taken in parallel from the rougher circuit and were simultaneously floated in the laboratory. The kinetic behaviour was then modelled at a laboratory batch scale in order to determine the time scale-up factor between laboratory batch flotation data and industrial size flotation. The time scale-up factor observed for large sized cells, 160 m3, was found to be reasonably similar to those previously determined for self-aerated mechanical cells, but of lower size, operating at similar recoveries. In addition, the relative effect of mixing, between laboratory batch and an industrial flotation bank, was quantified by the parameter, separating the impact that kinetic and mixing changes have on the time scale-up factor. In general, the rougher flotation operation was found to reach the predicted metallurgical target, and the optimal separability criterion was also respected. The diagnostic generates information about the internal state of the process and helps to identify potential improvements for design, operation and control of the circuit.

Jan 1, 2005

By J Lombardi, M Weidenbach

"OZ MineralsÆ Prominent Hill copper-gold concentrator is located 650 km north-east of Adelaide, 130 km north-east of BHP BillitonÆs Olympic Dam operation and 130 km south-east of the regional township of Coober Pedy, in the Gawler Craton region of South Australia. The concentrator was built in 2008 and commenced commercial production in early 2009. The Prominent Hill concentrator is comprised of a conventional grinding and flotation processing plant with a 10 Mt/a ore throughput capacity, operating well over the design rate of 8 Mt/a. Increased throughput rates have seen a decreased water recovery from the tailing thickener due to operating above design. Subsequently, greater pressure was placed on the site water balance and bore field off-take rates due to increased evaporation losses from greater volumes of water reporting to the tailing storage facility. This resulted in a trade-off between water availability and milling rates as part of the operating strategy.Two projects were implemented to increase the tailing thickener underflow density, thus improving water recovery directly back into the operating plant, reducing water losses via evaporation and decreasing the reliance on the bore field system operating at maximum rates to maintain mill throughput. The two projects were: tailing thickener feedwell redesign implementation of the Manta Cube control system.This paper discusses the background, implementation and benefits attained from these two key projects. Combined they have allowed a two to three per cent increase in tailing thickener underflow density to be consistently achieved, which has allowed greater water recovery. As a result, the processing plant has been able to operate at higher throughput rates when required, with greater water availability in the process plant recirculating system and a reduction in occurrences of the plant being æslowed downÆ due to water supply shortfalls. Both projects have also delivered a significant reduction in flocculant usage.CITATION:Weidenbach, M and Lombardi, J, 2012. Tailing thickener operability and control improvements at Prominent Hill, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 137-142 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 29, 2012

By A K. Ghosh

"Inrush of water is always an issue, especially for mines located in heavy rainfall areas. Nowadays, mining companies and research institutes have developed many advanced technologies for study and analysis of hydrological processes. In this paper, an advanced method is introduced, which uses the Shuttle Radar Topography Mission Digital Elevation Model (SRTM DEM) data in the Geographical Information System (GIS) platform to simulate the stream distributions around two specific mines: Super Pit and Griffin coalmine in Western Australia. The impact of this approach is important because it reduces the time and economic cost by creating a high spatial resolution hydrological map in the specific areas. The study identifies the flow path of the run-off water, which helps in adopting a suitable water management plan surrounding the case study mines. The results match with the ground reality. Based on the results, the stream structure around Griffin coalmine is more complicated than that of Super Pit. The bifurcation ratio and drainage density are computed to estimate the subsoil permeability characteristics of the two mines. Recommendations have been put forward to prevent and reduce the potential risks of water accumulation around the open pit mines.Citation:Ghosh, A K, 2016. Application of Shuttle Radar Topography Mission Data in Hydrological Analyses of Super Pit and Griffin Coal Mine, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 162–169 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

The Wattle Dam gold mine, located near Kambalda in the Goldfi elds region of Western Australia has recently progressed to an underground operation and is now believed to be Australia's highest grade operating gold mine. At end of March 2010, the deposit had reserves of 132 000 t @ 20.8 g/t for 88 000 oz and by the end of June 2010 had produced 110 000 oz from open-pit and underground mining. The Wattle Dam main lode is characterised by very coarse gold mineralisation. Gold occurs as cm to decimetre fracture fi ll veinlets, shear surface coatings and erratic fl akey clusters. The gold has no quartz or silica association and lacks adjacent low-grade mineralisation or alteration assemblage. Geologically it appears atypical of Archaean lode gold deposits and may represent an extreme end member of the type. Definition of the lode is largely dependent on effective geological identification of the host lode zone and an understanding of the erratic distribution and grade behaviour of a high-nugget, coarse gold deposit. Dependence on assay data to defi ne the lode zone would result in the deposit being mined incorrectly and much of the deposit being left unexploited. This paper discusses the geology, coarse gold characteristics and defi nition methods which are used to successfully defi ne and mine the deposit.

Aug 1, 2010

The sedimentary basins of this region developed in the collision zone of thePacific Ocean plate and the continent. Stresses were transmitted thorough wedge-like lithospheric blocks, such as the Okotsk Sea, East Kamchatka, Aleutian and other smaller blocks. Compression and inversion were more active at the boundaries: ***INSERT EQ*** and ***INSERT EQ*** in places. Tension, rifting and the increase in the rate of sedimentation were marked in P1-2, P3, N12, and also in N2 û Q in places. Structural plan changes of the sedimentary basins and possible oil, gas and fluid migration occurred more actively at the boundaries: ***INSERT EQ***.

Jan 1, 1995

Much attention in controlling blast vibrations has been centred on the probability of causing damage to structures in the area adjacent to where blasting is carried out. In most cases these structures are residential properties and the effect of the vibrations on the occupiers has not been studied to any great extent. This paper looks at the sources of disturbance caused by blasting and their psychological effect. A comparison of ground vibration levels for compliance is examined within the framework of structural and human response.

Jan 1, 1998

By T van der Meer, A Salokannel, M Martikainen, L M. Nevatalo, J McCulloch

Water use and wastewater management is becoming a focus for many industries around Australia and the rest of the world. Good quality water is increasingly being recognised as a precious resource, and regulations on the bulk storage and discharge of waste streams is becoming more stringent in order to protect the environment, existing water reserves and the communities that use these resources. Components such as heavy metals, arsenic, cyanide, and sulfate from acid mine drainage are some that occur at mining and metallurgical processing sites. Removal of such components can allow safe re-use of these streams, reducing the new water requirements of the process, or else allowing acceptable discharge to the environment. Re-use or discharge of treated water eliminates or reduces the risk associated with storage of large volumes of contaminated water on site.Technologies where a contaminant is selectively precipitated and removed as a sludge are used for many of these treatments. Selection of the best treatment option for wastewater must depend on what is suitable to each site, and consider not only the nature of the contaminant, but also other aspects, including the location and situation of the site, local regulations, cost of reagents, the sensitivity of the local environment and waste sludge disposal options. To outline how an effective and economical solution can be designed and delivered, this paper will present a case study for the removal of arsenic from a site wastewater, from assessment of the problem, selection of suitable technology, design and implementation, to the benefits delivered to the site.CITATION:Salokannel, A, Nevatalo, L M, Martikainen, M, van der Meer, T and McCulloch, J, 2013. Technology selection for removal of contaminants from an industrial wastewater, in Proceedings MetPlant 2013 , pp 531-538 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

Although mining, particularly of gold and coal, played a significant role in the development of New Zealand, from the time of the spectacular gold rushes of the 1860s its economic importance to the country as a whole has decreased substantially since that time. Gold, coal and non-metallic agricultural and industrial minerals have been found in economically significant quantities, however, the search for base metals has not been successful.

Jan 1, 1982

Flat jack stress determinations in selected colliery roadways have revealed a range of measured stress from 330 lb/sq. in. tension to 3,750 lb/sq. in. compression. Photoelastic examination of loaded plastic and actual rock model mine openings has shown that the primary horizontal stress required to attain these measured stresses would be from one to three times the superincumbent vertical load.Examination of roof movement with a borehole extensometer and a series of anchors at various horizons to 30 feet in a vertical roof borehole showed that when a standing face was advanced the roof movement was practically confined to the lower two feet. The majority of this movement occurred during the 36 hours after mining at this face commenced.The use of a radioactive isotope and a scintillation counter in a pair of parallel boreholes is a sensitive and accurate method of roof bedding plane crack detection.INTRODUCTIONA knowledge of strata stresses is required to understand the deformation of an underground opening and, in particular, the roof behaviour. It is the aim of investigations currently being conducted by Australian Coal Association (Research) Ltd. to determine the stress existing around mine openings and the location and magnitude of roof movement.STRATA PRESSURE MEASUREMENTMost measurements of strata stress are performed at the surface of underground openings and the majority measure the change of strain resulting from stress relief. The accuracy of the measured value of stress depends upon knowledge of the rock modulus of elasticity. The flat jack method has the advantage that strain relief is restored by a measured stress applied directly by the jack. The rock modulus of elasticity can also be determined.

Jan 1, 1963

By H Ishikawa, R Halomoan, S Palaniandy

The Karara iron ore project is a magnetite operation consist of open pit mining and concentrator to produce high-grade magnetite concentrate. The concentrator has adopted three stages of comminution, ie fine crushing in the high pressure grinding rolls (HPGR), primary ball milling and fine grinding in the TowerMill plus magnetic separation in between these comminution devices. Since 2014, the concentrator has increased the plant feed rate by 18 per cent. Meanwhile, the ore hardness has increased by 13 per cent to a Bond work index value of 15 kWh/t that led to a coarser flotation feed. Karara Mine has decided to shift the comminution workload from the primary ball mill to the TowerMill circuit by bypassing the 100 µm fine screen in between the ball mill and TowerMill circuits. This action has increased the circuit feed particle size distribution with a top size close to 1 mm. The specific energy consumption of the TowerMill circuit was approximately 3.4 kWh/t, and the circuit product sizes (P80) were ranged between 38 and 45 µm. A joint process improvement exercise was carried out to reduce the circuit product size closer to the magnetite liberation size, ie 35 µm. Among the activities were circuit audit, recommendation for improvement, modelling and simulation, multicomponent analysis, implementation of recommendations and quantification of the improvement. One of the key findings was the density effect of multicomponent minerals in the hydrocyclone. The analysis revealed that the low density coarser gangue minerals were bypassed to the hydrocyclone overflow stream that has resulted in a coarser particle size distribution. Meanwhile, more than 20 per cent of fine (-35 µm) high-density magnetite particles were recycled back to the mill through the hydrocyclone underflow stream and increased the circulating load. Based on these outcomes, several recommendations such as conversion to bottom feed configuration, use of smaller grinding media, high operating hydrocyclone pressure and additional grinding power to the TowerMill circuit were made to improve the overall circuit performances. Karara Mine has prioritised to implement those recommendations that have a minimal financial implication. Full-scale plant trials with bottom feed configuration and 17 mm grinding media were conducted to evaluate its performances. These trials have indicated that the grinding efficiency in the TowerMill was enhanced by 10 – 30 per cent. In May 2017, all the five TowerMills were converted to the bottom feed configuration. This paper discusses the impact of shifting the comminution workload load from the primary ball mills to TowerMill circuit and the performances enhancement of the TowerMill circuit. CITATION:Palaniandy, S, Halomoan, R and Ishikawa, H, 2018. Shifting the comminution workload from the primary ball mill to TowerMill circuit, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 163–176 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By I Auranen, J Raatikainen

IMA Engineering (IMA) and Mine On-Line Service (MOLS) companies have used on-line sensors for analysing ore and waste rock in mining for more than 25 years. Today IMA on-line sensors are used in various stages of the mining process including on-line analysis of drill cores, drill chips, ore and waste in loader bucket, ROM ore analysis on belt conveyor belt and in bulk ore sorting and in slurry analysis in concentrators. During years of extensive field experience and testing we have found that the waste rock dilution and ore losses create much larger economic and environmental losses than has been previously recognized. According to our studies the main reason is limited number of analysis already in exploration when drill cores or drill cuttings are used in block modelling. The same happens in production because too few and biased samples from benches are used to estimate the ore grade. Much more than today estimated amount of waste enters the mill and considerable volumes of ore losses happen at the same time. The ore grade on the benches and in muck piles is averaged and “homogenized” with averaged and biased samples. These are the main root causes of waste rock dilution and ore losses. Sensor based preconcentration can be the remedy to waste rock dilution and ore losses. This presentation will show examples of the use of on-line sensors in preconcentration when analysing ore and waste rock in drill cores, drill cuttings, on conveyor belt and in bulk ore sorting. Waste rock removal in preconcentration has direct effect on energy consumption in crushing and grinding and chemicals in concentrator. In concentrator waste is separated and goes to tailings pond, however, preconcentration directly reduces the volume of the tailings. In our presentation we will cover cases in base metals and in gold mines.

Nov 10, 2020

By D Reid, A Fourie

The in-pipe treatment of slurries with polymer addition shortly prior to deposition is a noteworthy emerging technology of increasing popularity. Although polymer treatment has been shown to substantially modify and improve depositional and dewatering behaviour in a significant number of cases, the impacts of polymer treatment on geotechnical performance of tailings are less well understood. For example, certain combinations of polymer and slurry type have been shown to result in lower final densities at a given vertical effective stress. Despite these lower densities, polymer-treated tailings often exhibit peak undrained shear strengths consistent with untreated material. However, the sensitivity and/or brittleness of the material may be negatively influenced by the looser state created. Although these changes have been studied, most testing available in the literature was undertaken on relatively ‘fresh’ samples of polymer-treated material. However, significant shear may occur following treatment and prior to the commencement of settling and self-weight consolidation as the material moves down the beach.To study the effects of shearing on the subsequent performance of polymer-treated tailings, a test program consisting of consolidation, triaxial and direct simple shear tests was undertaken on presheared polymer-treated material. Materials used were identical to those used in previously published studies on the impacts of polymer treatment in a ‘fresh’ condition. Shearing of the polymer-treated material generally appeared to lessen the impacts of the polymer treatment process. However, the behaviour of the material when sheared indicated that the polymer was still impacting the behaviour of the material in some respects. The results indicate the importance of the consideration of shearing on material behaviour when planning and designing a tailings deposit where polymer treatment is to be implemented.CITATION:Reid, D and Fourie, A, 2015. Effects of shear on the behaviour of polymer-treated slurries, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 215–224 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By R Dimitrakopoulos, I Minniakhmetov

Geostatistical simulation techniques are used to quantify uncertainty of spatial attributes of interest describing mineral deposits, petroleum reservoirs, hydrogeological horizons, environmental contaminants and so on. The majority of existing methods consider second-order spatial statistics and Gaussian processes, while the more advanced multiple point-based simulation approaches are algorithmic and do not consistently account for the high-order spatial relations in data. Recently, simulation techniques for complex and non-Gaussian spatially distributed variables have been developed, based on high-order spatial cumulants, and make no assumptions on data distribution or require data transformations. In this paper, the previous developments are extended and a new approach for the joint simulation of multiple correlated variables using high-order spatial statistics is proposed. The technique is based on a new algorithm for the decorrelation of correlated variables into factors, using the so-termed diagonal domination condition of high-order cumulants. The decorrelated factors are then simulated using high-order simulation and back-transformed into the initial correlated variables. The decorrelation using diagonal domination of high-order statistics is tested with a data set from a multielement iron ore deposit, and then a fully known two-dimensional data set with two correlated variables is used to demonstrate the practical intricacies of the proposed method.CITATION:Minniakhmetov, I and Dimitrakopoulos, R, 2014. Joint simulation of correlated variables using high-order spatial statistics for orebody modelling, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 53–60 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By S Sullivan

A recent review of resource reports lodged to statutory bodies found geological models with oversmoothed or unrealistic lithological boundaries, many of which do not represent geological appearance in the field, pit or underground drive. The underlying data is often too complex or messy to be incorporated into the resource model and is thus a simplification of reality, to the detriment of the mining operation and its shareholders. Volumes can be over- or underestimated and subsequent grade predictions can be misplaced, combining to cause over- or understatement in resource reporting to stakeholders and statutory authorities. Domain models can be improved with new modelling techniques such as machine learning. However, with poor data or improper use of machine learning techniques, the conclusions can be just as misleading as with current techniques. Machine learning rarely offers a single ‘right’ outcome, rather a range of possible outcomes from the data provided. But importantly it can take advantage of the full richness of data for more informed models. Machine learning also provides confidence in its predictions so that uncertainty in the resultant models can be quantified and passed through for risk assessment during mine planning and operation. This paper will discuss the factors accentuating complexity in deposit modelling: data diversity, structural controls, chemistry, data volumes, process workflows and external non-geological constraints. A case study illustrates the risk of reducing or ignoring complexity, which can result in an overly simplified geological model.

Mar 22, 2022

Resue or split face firing has the potential to separate ore and waste rock into separate muck piles within a stope. Thus split face firing has the potential to reduce dilution of the ore stream to be transported to the surface for subsequent processing. It also potentially reduces the total amount of broken rock needing to be transported out of the mine as the waste material is physically separated from the ore as part of the blasting process. Waste can therefore be used directly from the stope to backfi ll other mining areas. This paper reports on the results of split face firing trials at the Hillgrove mine in NSW and analyses the results of these blasts.

Aug 1, 2010

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

By Edmonds W, Jeffcoat R

The completion of the first two open hearth furnaces in the new No. 2 open hearth plant at Port Kembla will increase Australian production of steel by 350,000 tons of ingots per annum.The paper gives an outline of the essential features of open hearth design and auxiliary equipment required to operate the two modern open hearth furnaces at present being installed.INTRODUCTIONThe increasing demand for steel required by Australian secondary industries led to the decision to construct and operate No. 2 open hearth plant at Port Kembla. Two basic open hearth furnaces of the most modern design are under construction and it is anticipated that these units will be commissi.oned in September 1956. Australian steel capacity will thereby be increased by approximately 350,000 tons of ingots per annum.PLANT LAY-OUT AND CONSTRUCTIONIn the design and lay-out of this plant the emphasis has been on efficient material handling with simplicity of design and operation. Overseas methods were studied and these studies, together with experience gained at Newcastle and Port Kembla open hearth shops, enabled this plant to be built to a standard which compares favourably with any other in the industry.Initially two furnaces, each of 2,75 tons capacity, have been built, but provision has been made in. the design and lay-out to enable expansion to six furnaces.The location of the new plant in relation to the existing units will be noted in Fig. 5. It is one of the first units to be built in an area which will dovetail into a pattern for...

Jan 1, 1957

By P Ottenio, B CarrT

In the last 40 years, the froth flotation process widely spread in the paper industry becoming the dominant technology for ink removal from recovered paper slurries and cellulose fibres recovery. Most of current models used to describe the flotation deinking process are based on hydrodynamic and statistical theories of ink particles collision/attachment to air bubbles. The complexity of these theoretical models, together with the variability of the recovered papers composition, does not allow to define a set of æeasy to handleÆ equations to be used for modelling industrial flotation cells. This main limiting aspect makes that, in several deinking process modelling tools, basic parameters used to characterise the flotation unit, ie yield, ink removal efficiency, water loss, are constant parameters. Although in some process simulation tools the flotation yield/efficiency is adapted to process control parameters (air ratio, pulp flow, pulp consistency), physicochemical variables (namely the pulp frothing aptitude, the pulp surface tension and the ink adhesion energy to air bubbles) are not taken into account to adjust the flotation yield/efficiency. Data collected during recent laboratory and pilot plant experiments focusing on the role of surface active substances on the flotation efficiency were therefore interpreted and used to identify general trends that could be described with simple semi-empirical models. A set of model equations using surface tension and froth removal height as main variables was then defined in order to describe the behaviour of a pilot flotation cell. Trends obtained during the dynamic simulation of the deinking pilot plant were in good agreement with experimental data obtained under similar experimental conditions, thus indicating that developed equations can forecast with good approximation the behaviour of a flotation deinking unit.

Jan 1, 2005

By K L. C Gontalves

In 1999, the Mineral Development Centre of CVRD (CDM) acquired a flotation device referred to as Mini Pilot Plant (MPP), which is able to run continuous flotation tests with drill core samples. Since then this equipment has been used to define the flotation circuit and process conditions during the pre-feasibility phase of CVRDÆs copper sulfide projects. Until now, the MPP results had not been validated for an industrial flotation operation. The present work consists of a comparison and correlation of the results from a flotation MPP and an industrial plant. In order to make this comparison, an industrial plant was completely sampled and the feed ore was tested on bench scale and on a MPP. The metallurgical and mass balances of each test were used for the comparison.

Jan 1, 2005

By Y Chen, G Xu, B Albijanic

High concentrations of airborne coal particles is the main reason leading to health and safety hazards in underground coalmines. Water spray is one of the effective methods to suppress coal particles in mine sites, but the use of plain water is not effective enough to capture coal particles. By adding surfactants, coal wettability can be improved which will increase the coal dust suppression efficiency. In this study, a modified sink test was employed to evaluate coal wettability in the presence of two anionic surfactants: sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS). Sink rates were calculated by measuring sink weight over test time. Different surfactant concentrations (0.01 per cent, 0.05 per cent, 0.1 per cent, 0.2 per cent and 0.4 per cent) and two types of water (tap water and deionised water) were selected to investigate coal wettability over three size ranges (0–38, 53–75 and 75–90 µm). The results show that both SDS and SDBS surfactants can lower the water surface tension and improve coal wetting performance. Sink rates increased as the surfactant concentration increased, and surfactant solutions prepared by tap water performed better than deionised water in enhancing coal wettability. Also, coal wettability varied for different coal particle sizes; the smaller coal particles were, the worse the wettability they possessed.CITATION:Chen, Y, Xu, G, Wang, R and Albijanic, B, 2017. Study on coal wettability for dust suppression in the presence of surfactants by sink test, in Proceedings Australian Mine Vent Conference 2017, pp 105–110 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017