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Adhesion of Escherichia coli onto Oxide Minerals - Extended DLVO Theory and Flotation Behaviour

Sep 13, 2010

Mining is both a high risk and a long term business. This is dramatically illustrated by the fact that, on average, the explorer will expend over $30 million in a ten year period for each significant economic discovery. The time required to complete the exploration process is one of the most substantial commitments made by any mining company. For example the time lag between the implementation of an exploration programme and an economic discovery is variously estimated to take two to ten years. The ore definition phase following discovery currently takes between two and five years while subsequent mine development may take one to two years in easy situations and up to 8 in difficult environments. In most countries the critical path through the early stages is determined largely by technical considerations but in almost all countries the path through the later phases is dictated by the plethora of permits, licences and community involvement steps.

Jan 1, 1982

By B K. Hebblewhite, F T. Suorineni, J D. Tibbett

Block caving is an underground mining method that can provide high production capacities at low operating costs. This enables the profitable extraction of massive, low-grade orebodies and attracts industry towards the method. Block caving operations require significant initial capital investment and predictable cave propagation is crucial to safety and economic success. Lack of access to observe the caving process hinders our ability to learn how the rock mass and geological structures are reacting to mining. Virtual reality scientific visualisation (VRSV) enables the integration and investigation of multiple, large caving data sets and provides a viable alternative to visualise rock mass response without physical access to the cave. Point instrumentation is incapable of providing an overview of cave performance and seismic monitoring, while providing an overview of the rock mass and the response of structures to caving, is only useful when linked to the caving activities. The integration of point instrumentation data with seismic monitoring information, coupled with scientific visualisation of the mining system in a virtual reality environment, provides a powerful means for understanding caving performance.This paper describes the use of a VRSV module at UNSW Australia, designed for investigating the block cave mining system from a case study operation. This module has been used to investigate the location and chronological evolution of seismicity to understand sources of damage resulting in seismic space-time sequences (SSTS) in the caving system. The events within an SSTS represent damage that is spatially and temporally related. An SSTS group represents a collection of microseismic events from a reasonably competent region of the rock mass that has experienced a stress change significant enough to cause sequential damage. SSTS group locations have been seen to be the path of subsequent cave propagation. Thus, SSTS analysis enables insight to further our understanding of rock mass damage in caving geomechanics through analysis of historic data. Such insight has operational potential to learn from recent rock mass activity for optimising the management of undercut advance, draw front advance and cave draw patterns.CITATION:Tibbett, J D, Suorineni, F T and Hebblewhite, B K, 2016. Understanding damage source mechanisms in a caving system using virtual reality scientific visualisation, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 439–452 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By B Hiebl, J Martens, L Petzold

A research team at the Iron and Steelmaking department at Primetals Technologies has established new upgrading measures for improving the efficiency of the beneficiation process in ironmaking plants, relying largely on pre-existing equipment. After the upgrade, the iron content in the final iron ore concentrate was shown to be significantly higher. Remarkably, the costs for employing the respective measures are surprisingly low.This case study is based on a Kazakh iron and steel producer, whose beneficiation process is currently generating a magnetite concentrate with a final iron content of 65.65 per cent. The study shows that the implementation of Primetals Technologies’ intelligent modification measures to the current beneficiation process, the realisation of more effective dewatering, and the utilisation of an innovative binder lead to an increased iron content in the resulting pellets, reaching a concentration of 69.17 per cent (iron ore concentrate) and 66.5 per cent (pellets).The current operation consists of three closed circuit grinding stages, four stages of low intensity magnetic separation, vacuum disc filters and straight-grate pelletising. By dividing the slurry after the second stage of grinding and the third stage of low intensity magnetic separation, it is possible to divert the more iron-rich fines before they would enter the third grinding stage and the fourth stage of magnetic separation. This then reduces the load on the existing third stage ball mill. Afterwards, the ground material is treated in an additional low intensity magnetic separator and mixed with the previously diverted fraction of the fines. An improved filtration procedure, combined with the application of a highly sophisticated binder, further reduces the amount of additives needed, so that a genuine direct reduced (DR)-grade iron concentrate is produced as a result.All laboratory, pilot and pelletising test work was executed at Primetals Technologies’ laboratories in Austria.CITATION:Martens, J, Petzold, L and Hiebl, B, 2017. Enabling iron ore concentrate for the production of direct reduced iron with pre-existing beneficiation lines, in Proceedings Iron Ore 2017, pp 227–232 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

To ensure that its voice is heard in the development of policies and plans under the Resource Management Act, the mining industry is challenged to participate in their preparation. This paper outlines a number of practical ways in which the industry can participate in debate on sustainable management and how it can be put into practice within the industry.

Jan 1, 1992

By H Hutchinson

Froth flotation is applied to mineral sand concentrates in order to produce commercially viable xenotime concentrates. Experiments indicate that a xenotime product containing 38% Y2O3 at 47% recovery or 34% Y2O3 at 83% recovery can be obtained from a 27% Y2O3 feed. The process involves a primary stage of reverse flotation at which oxide and silicate gangue is floated, and secondary stage of direct flotation at which xenotime is floated. Of the various collectors screened an amphoteric compound was found to be effective at both stages. This was made possible by the addition of sodium silicate at the second stage, which acted as depressant for the remainder of the gangue. Similar studies on a low grade feed material were somewhat unsatisfactory as the grade achieved fell short of what was targeted.

Jan 1, 1990

By R Blair

The Domain and Burnley Tunnels, which are major features of the Melbourne City Link Project, are MelbourneÆs first road tunnels. They are 1.6 km and 3.5 km in length respectively and are being constructed through a variety of ground conditions. Deeper sections of the tunnels have been driven through the Silurian mudstone which underlies Melbourne. Other shallower sections of the tunnels pass through a variety of ground conditions including silts, sands, clay and rock and have been constructed using both top-down and bottom-up cut and cover construction techniques. The Yarra River Crossing is a 140 m length of the Domain Tunnel which crosses under the Yarra River on a relatively shallow alignment. The crossing of the river using cut and cover techniques was identified in the early stages of design development as being one of the most challenging stages of the works on the Southern Link. The prevalence of varying geological conditions combined with the need for maintained traffic and stream flow conditions provided a demanding and often conflicting set of criteria for which there appeared to be no one clear solution. A team of designers, constructors, estimators and specialist contractors were involved in a concept evaluation and risk analysis study spanning a period of approximately 12 months. During this study, four concepts were considered as likely contenders. This paper provides a brief outline of the four concepts addressing their relative merits, disadvantages and risks followed by a detailed description of the adopted solution, namely top-down construction using secant pile walling (east bank) and bottom-up in situ construction (west bank).

Jan 1, 1999

In recent years there have been many changes in mine ownership due to the on-going rationalisation towards larger mining companies. Larger companies inevitably find it hard to manage small mining operations and in many cases smaller mines do not fit corporate resource, production and profit criteria. Smaller companies are more suited to managing these medium or small scale mines and are tendering for the purchase or lease of mines that larger companies wish to dispose of. In addition to these factors there has also been a trend (especially in Western Australia) for mines to continue operating at ever increasing depths. This in turn has led to more mines operating in high stress environments and experiencing damaging seismicity. Assessing the viability of seismically active mines from a takeover or purchase point of view should involve analysing the risk profile of every aspect on mining that could be affected by adverse seismicity. This includes assessing current and alternative mining methods, mine designs, support systems, extraction sequencing, monitoring and blasting. This paper includes discussion on items that need to be assessed when considering the purchase of seismically active mines, with experience gained from some recent studies in Western Australia. In these cases it was apparent that quantification of previous seismic history on itÆs own was a totally inadequate method of assessing minewide seismic risk potential. A more holistic approach is required, taking into account all aspects of relevant data, all the minewide effects of seismic activity and all possible means of mitigating those effects.

Jan 1, 2002

By W E. Vance, B H. Ashton

The emission of seam gases into underground workings in coal mines is acknowledged as a major hazard, particularly methane due to its possible ignition. Acknowledge of seam gas parameters is important for the prediction of gas emission rates into the ventilating air current. They are also important as the basis for the evaluation of the likely contained gas as a possible energy source.   Gas content determinations for the Kupakupa seam have been made at the Huntly West Mine.  Applying the method of Creedy (1986) to face samples, gas contents of 1.80 and 1.66 have been determined. Using desorbed and residual gas content data a content of 1.92 m3/t has been derived. These are on an ash included basis. Calculations using the adsorption equation of Kim (1977) and coal quality have given a gas content of 2.19 m3 t. Long-hole exploration drilling at Huntly West Mine has provided information on gas pressure. A pressure rise test has given a reading of 500 kPa (absolute); this is low compared with the pressure given for the determined gas content from theoretical adsorption isotherms.

Jan 1, 1991

A key issue in maintaining the mining industryÆs social contract to access community-owned resources, is the need to be able to demonstrate professional management of resource extraction and the risk associated with mining hazards. Significant failures such as disease relating to coal dust and asbestos and mine disasters such as Moura, Appin and Gretley have resulted in judicial and legislative interventions that respond to the community outcry but do not necessarily effectively manage the longer term risk in a sector driven by new technology. With the implementation of recent amendments to the Queensland Professional Engineers Act, senior engineers in all industries including the mining industry are required to be registered and to demonstrate that they have æmaintained competency in the practice of engineering in the area of engineering for which the (engineer) is ... registeredÆ. This may be facilitated through a report produced by an æAssessing EntityÆ. These entities are approved by the Minister on advice from the Board of Professional Engineers, Queensland. Engineers Australia and The Australasian Institute of Mining and Metallurgy (The AusIMM) are the two professional bodies approved as æassessing entitiesÆ charged with facilitating successful implementation of the process established by the legislation. The scope of the legislation covers engineering enterprises in Queensland and engineering activities elsewhere that may have been designed in Queensland. There is currently a challenge to determine what the necessary health and safety competencies for the mining industry are and how the maintenance of these competencies will be assessed. The different approaches taken by the two assessing entities are compared and contrasted. At the legislative level, establishing an obligation to assess professional competency is simple, but at the level of the profession, it is new ground that warrants a substantial research and development input. The challenge is to develop criteria by which the quality of such system can be assessed. The comparison is made by considering such issues as equity, effectiveness, efficiency, objectiveness and transparency. These five indicators are considered in terms of how they are applied in other sectors and how they might be applied in the mining sector.

Jan 1, 2009

By G J. Fleming

The Miwah prospect lies on the dilational 070¦ trending Miwah Lineament near its intersection with northerly oriented fractures within Pliocene volcanic rocks exposed between a NW trending segment of the dextral transcurrent Sumatra Fault, and the more northerly trending Samalanga-Sipopok Fault to the east. These faults reflect the continued interaction between stresses from the India-Australia plate located to the southwest, and spreading within theAndaman Sea to the north of Sumatra. A system of deep seated faults is believed to have facilitated emplacement of post-Miocene magmas and Quaternary volcanic centres at shallow crustal levels throughout northern Sumatra. Miwah mineralisation is associated with variably dipping structurally and lithologically controlled argillic and advanced argillic alteration. An oxidised supergene leached zone and a recent, thin, unaltered tuff blanket partly overlie the mineralisation. Mineralised zones are commonly brecciated and veined, and display quartz, quartz-alunite, quartz-alunite¦pyrophyllite¦kaolinite replacement assemblages, surrounded by more weakly mineralised, often vugghy quartzalunite¦pyrophyllite¦kaolinite advanced argillic, and argillic zones of quartz-kaolinite, quartz¦pyrophyllite¦kaolinite and smectite-illite-quartz. Propylitic assemblages are marginal to more intensely altered zones. Hypogene copper mineralisation is typified by enargite, luzonite, and covellite. The host mineral to gold is uncertain at present. Rare barite, native sulfur, and ?telluride also occur. Bornite and chalcopyrite have been observed in transported altered rocks in faults. Generally the mineralisation is anomalous in precious metals, locally enriched in Cu, erratic in Pb, and depleted in Zn, with a good correlation between Cu-As-Ag.

Jan 1, 1995

By J M. Marwan, B Tang

Strain-type rockbursts, or strainbursts, are characterised by a localised violent failure. Their cause is attributed primarily to the sudden release of strain energy, which accumulates in a volume of highly stressed rock as a result of mining activities. Examples of such phenomena are crown/sill pillar bursts created in the mining process, pillar crush in room-and-pillar mining, face ejection in drift development headings at depth, and floor bursts associated with deep shaft sinking. The paper describes a simple method for the assessment of crown pillar bursts in steeply dipping ore deposits which are extracted by the overhand cut-and-fill method. The method is based on a theory previously established by the author to help assess the need for a remedial solution such as pillar destress blasting. Basically, the mining-induced energy storage rate (ESR) in the pillar is compared with the critical strain energy to come up with the so-called burst potential index (BPI).

Jan 1, 2001

Separation of Iron Particles from Banded Haematite Quartzite (BHQ) Ore by Selective Magnetic Coating The separation of fine iron particles from banded hematite quartzite (BHQ) has been studied using selective magnetic coating. The BHQ ore assays as 38.9 per cent Fe, 42.5 per cent SiO2 and 1.0 per cent Al2O3. Mineralogically, the ore contains hematite and quartz as the major mineral phases where as goethite and magnetite is present in minor entities. Natural magnetite of very fine size and oleate-magnetite in colloidal form, prepared synthetically in the laboratory are used as the coating material on the surface of hematite particles. The selective coatings of oleate-magnetite on BHQ surfaces followed by magnetic separation studies have indicated that, it is possible to achieve 62.3 per cent Fe with 8.5 per cent SiO2 at 85.4 per cent iron recovery. The recovery of iron values is found to be superior in comparison to the conventional magnetic separation techniques. The selectivity of coating for enhancing the magnetic response of iron particles is achieved by controlling the surface properties of the particle via electrokinetic potential adjustment by controling pH and addition of oleate-magnetite. In the separation process, the effects of pH, magnetic intensity and addition of oleate-magnetite are studied to achieve the maximum grade and recovery of iron values. The optimum separation is observed at pH of 7.5, oleate-magnetite concentration of 0.25 ml/g of BHQ ore and a magnetic intensity of around 0.8 Tesla. The X-ray diffraction (XRD), Infra-red spectroscopy (IR) and UV-visible spectroscopic studies strongly suggest preferential coating of magnetite on hematite surfaces. Scanning electron microscopy (SEM) studies have brought out the semi-quantitative features of BHQ ore. The recovery of iron values from a lean grade ore such as BHQ is carried out looking into the future needs of this ore in India for iron and steel making.

Sep 13, 2010

By K Palmer

Alluvial platinum was recovered during gold mining operations in Maud Creek, a tributary of the Howard River. Average electron probe analyses give Pt 88.75, Fe 5.27, Ir 0.70, Os 1.06, Pd 0.34, Ru 0.14, Rh 1.29, Cu 1.06. Rare grains of a Pt-Fe-Cu alloy are also present and an unusual feature of all grains is the relatively high rhodium content which finds expression in segregations of rhodium arsenide, cherepanovite. Platinum is found in the Orepuki area of Southland, where it is probably partly derived from the mafic rocks of the Longwood Complex. Rocks of the Rotoroa Complex, similar to those of the Longwood Complex, form bedrock in Maud Creek and are possibly the source of the Howard platinum. Alternatively, it might be derived by glacial transport from the Matakitaki ultramafic block 30 km to the southwest. Origin from the Rotoroa rocks is preferred as, if the Matakitaki rocks are part of the Dun Mountain Ophiolites, they might be expected to contain osmiridium rather than platinum. The ratio Pt:Ir-Os has been widely used to distinguish low Pt:Ir-Os ophiolitic from high Pt:Ir-Os gabbroic assemblages. Mafic complexes such as Longwoods, Darran, Rotoroa, and Riwaka might be expected to show similar high Pt:Ir-Os ratios and be targets for platinum exploration. Detrital platinum examined from the Parapara area, Golden Bay is mainly osmiridium, with rare grains of rutheniridosmine, very similar in composition to that found in concentrates from the Kaniere dredge, West Coast.

Jan 1, 1987

By L Langer, R Simcock, M Davis

Rehabilitation of mining sites helps to achieve the purpose 5(2c) of The Resource Management Act 1991 û æavoiding, remedying, or mitigating any adverse effects of activities on the environmentÆ. The environmental outcomes for recent and current mining operations on the West Coast are variable. There are some exemplary mining operations which are restoring or even improving land use and environmental factors in the region, particularly those operated by the larger mining companies. There are also examples of an exploitative mentality where the environment and land have been severely degraded by mining activities. Technology has been developed to prevent a repetition of the historical destruction of the environment through mining. Failure to rehabilitate mined land is no longer acceptable to the New Zealand public in the 1990s and damages the credibility of the mining industry. Examples of successful mine site rehabilitation to pastoral farming and to production or plantation forestry are illustrated from the alluvial gold mining industry. Planning, sequencing of operations, the utilization of sailor plant growth materials, and aftercare are key factors in successful land rehabilitation to these productive uses. There is also a recent focus on restoring indigenous forests and wetlands at both coal and gold mining sites, particularly for mines on or adjacent to the conservation estate. The results of scientific research and efforts by the industry on techniques for rehabilitating rainforest and pakihi wetland after mining are presented, particularly from the Giles Creek Dunoille Coal Mine. There is a need for further research and trials to apply and extend rehabilitation techniques to other geological and environmental situations, particularly to mines in mountainous areas and to difficult environments like the coal measures ecosystems of the plateaux above Westport.

Jan 1, 1996

By B B. Du, Y N. Lu, L X. Wang, S L. Wu

The cohesive zone in the blast furnace is largely affected by the softening and melting behaviour of ferrous burden because of its vital role in the blast furnace process. The Visual High Temperature Methodology (VHTM) has been given to study the softening and melting behaviour of sinter, two kinds of lump ores and acid pellet intuitively. Before softening, both two kinds of lump ore swelled and more serious for lump ore B because of its denser structure than lump ore A. The softening and melting temperature intervals are different from one another and this phenomenon contributed to the gas permeability of ore layer in the cohesive zone since the ‘ore window’ has formed. Besides, the softening and melting behaviour of mixed burdens have been studied, where it has been found that the softening and melting characteristics of mixed burden A (consisting of sinter and lump ore A) is better than mixed burden B (consisting of sinter and lump ore B) and mixed burden C (consisting of sinter and acid pellet) despite the poorest characteristics of lump ore A. The reason is that the high temperature interactivity between lump ore A and sinter is much better than lump ore B and acid pellet. The high temperature interactivity is mainly influenced by the chemical compositions, porosity and contact condition. This paper provides a new research method for the softening and melting behaviour of iron ore and an important technical basis for the optimisation of blast furnace burden.CITATION:Wang, L X, Wu, S L, Lu, Y N and Du, B B, 2017. The softening and melting behaviour of single and mixed iron ore burdens, in Proceedings Iron Ore 2017, pp 605–610 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By C Bailey, T Kojovic, M M. Hilden, M S. Powell

The Julius Kruttschnitt semi-autogenous grinding (SAG) mill model was developed by Leung in the 1980s and extensively updated to the variable rates model by Morrell and Morrison in 1996. Since then only minor upgrades have been incorporated in the version distributed in the JKSimMet simulator. A number of improvements, developed over the course of the AMIRA P9 project and in recent independent work, have now been incorporated. These improvements are based on a power-based model that directly relates the degree of breakage with energy consumption. The new size-dependent breakage function has been incorporated. The upgrades include more accurate predictions for a wide range of mill fillings (ten - 40 per cent), slurry hold-up in the mill, pebble discharge rate and the influence of changes in feed size and ball load.The paper presents the status of progress in the model development. The upgraded model will greatly enhance its application to challenging design and optimisation studies required to optimise the performance of SAG milling circuits.CITATION:Kojovic, T, Hilden, M M, Powell, M S and Bailey, C, 2012. Updated Julius Kruttschnitt semi-autogenous grinding mill model, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 71-80 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

Distribution of Settling Velocity of Irregular Particles and its Effect on Jig Separation Efficiency

Sep 13, 2010

By W J Fisher

Northern Australia leads in world-class mineral deposits' is a bold statement. First there must be a starting point. Land north of the Tropic of Capricorn (23¦ 26' 5") will be regarded as Northern Australia covering nearly 40 per cent of the land surface of Australia. As opposed to land south of the Tropic of Capricorn, it should be regarded as Tropical Northern Australia and for the sake of brevity, (TNA) Refer Figure 1. Apart from the tyranny of distance from centres of power and population in the temperate zone, it suffered in the past from the belief that the tropics are unsuited for European workers and from the lack of infrastructure. Outstanding mineral deposits of iron, base metals, gold and diamonds, discovered and developed in the past three decades, provided the substance for the title. There are many world-class mines producing and there are mineral deposits neutralised through Government policy. TNA can maintain its lead in world-class mineral deposits provided Government policy will stop partitioning the land and decreasing that available for exploration. Let's look at what we have that is world-class. In Western TNA iron ore deposits at Paraburdoo, Mt Tom Price, Marandoo, gold at Telfer, diamonds at Argyle. In central TNA uranium at Ranger and Jabiluka, lead-zinc-silver at McArthur River, gold at the Tanami, manganese at Groote Eylandt and bauxite at Gove. In eastern TNA Mt Isa, Hilton, Century zinc-lead, bauxite at Weipa, gold at Kidston, Mt Leyshon, magnesite at Yamba and coal mines in the Bowen Basin. Those mines or deposits stand out yet are only an indication of the numerous lesser mines and of mineral deposits depending for development on market demand and/or changes in Government policy, eg 'The Three Mines' policy. Very large areas of mineral rich structures in the western, central and eastern parts of TNA are concealed below flat lying comparatively young unmineralised sediments. The Great Artisan basin sediments in eastern TNA can and do host oil shale and non metallic minerals. Nearly 40 per cent of western TNA is covered by the Great Sandy Desert. The Canning Track, with a series of 54 wells, was constructed by surveyor Alfred Canning in 1908 - 1910 with great difficulty. It extends 1700 kilometres from Halls Creek in the north to the gold town of Wiluna in the south, through the Great and Little Sandy Deserts. Gold explorers are following favourable structures extending to the north east below the sediments and sand hills covering the track. Half of central TNA's mineral structures are concealed by the Tanami desert and the Cretaceous sediments covering the pastoral regions of the Barkly Tableland and the Daly Waters to Top Springs pastoral areas. The Georgina Basin in the south eastern section is part of the concealment.

Jan 1, 1994

By D Craw

Sulphur-rich minerals such as authigenic pyrite (FeS2) are commonly associated with coal mine workings. Metallic elements such as arsenic (As), copper (Cu) and zinc (Zn) are enriched in the pyrite relative to their concentrations in the surrounding environment. Exposure of pyrite and coal to air and water results in a series of oxidation and hydrolysis reactions that are commonly catalysed by species of Thiobacillus bacteria. These reactions lead to a lowering of the pH in the drainage waters (acid mine drainage, AMD) and subsequent mobilisation of trace metals in environmentally significant concentrations. This study assesses the spatial distribution of As, Zn and Cu concentration in water in relation to pH and Eh (redox potential) downstream from the tailings at the Wangaloa opencast lignite mine in southeast Otago. This mine was abandoned in the late 1980s due to a decrease in the economic viability of mining the lignite. The area is showing the characteristic symptoms of AMD, which is detrimental to the health of several Pinus radiate growing on some of the tailings. The pH of the drainage waters can get as low as 2, and in some instances, lower, but it returns to near neutral (pH 6.5) up to 200 metres down stream from the base of mine waste piles. It is well documented that the atmospheric oxidation of pyrite is catalysed microbially, causing a substantial decrease in the pH of the drainage waters. Acidification is then counteracted predominantly by natural abiotic remediation processes occurring downstream.

Jan 1, 1999