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By D. Bois, P. Keating, J. Lemieux, M. A. Vallée, M. Allard, R. S. Smith, L. Z. Cheng, M. Chouteau, D. K. Fountain

"As part of a larger research program, a number of MEGATEM airborne electromagnetic (EM) test flights were flown over the Gallen massive sulfide deposit in northwest Québec. A particularity of this test site is that a major part of the ore body was extracted before the MEGATEM survey. Therefore one of the purposes of this study was to verify the ability of the system to detect the remaining massive sulfides below the water in the open pit. The open pit is also surrounded by a metallic fence, and a power line is present in the vicinity. A large part of the case study involved accounting for the impact of infrastructure and acidic water on the survey, which will help in the interpretation of airborne EM responses in complex exploration situations.The Gallen deposit was also previously flown with the INPUT and GEOTEM airborne EM systems before the major exploitation period. A comparison between the results from the different survey results allows estimation of the physical properties of the Gallen deposit, which is a relatively poor conductor.A new method for removing the power line signal shows amplitudes with a smaller residual associated with the emanating fields, and more compact, cleaner responses associated with induced currents. This will make it easier to identify bedrock conductors close to power lines"

Jan 1, 2007

By J K. Claflin, S R. La Brooy

A case study from a current Ausenco project is presented to demonstrate the importance of maintaining high carbon activity to illustrate the driving force for plant improvements such as a carbon regeneration kiln upgrade.This paper revisits the factors that influence carbon activity for gold loading, with emphasis on deactivation by organic solution components such as flotation reagents.Kiln process design requirements for effective thermal regeneration are reviewed including the interaction of parameters such as temperature, kiln atmosphere and residence time.The different types of kilns that have been used for carbon reactivation are described. A check list is provided of what to look for when purchasing a carbon reactivation system for dealing with severely fouled carbon. This covers the ancillary equipment as well as the kiln itself.While the effectiveness of the carbon reactivation kiln is vital to maintenance of high carbon activity it needs to be remembered that this is only the end of pipe solution. It is also important to ensure that reagents such as frothers and flotation collectors are appropriately chosen to maximise recovery and at the same time minimise carbon deactivation.CITATION:La Brooy, S R and Claflin, J K, 2013. Carbon management in a high gold price environment, in Proceedings MetPlant 2013 , pp 455-467 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

Ore from the "Staimite" lode in the Oonah mine, Zeehan, has a complex composition and contains an exceptional number of elements. Its chemical composition has been indicated by the following published figuresà

Jan 1, 1931

The objectives of this paper are to introduce the International Code of Practice for Risk Management of Tunnel Works and to illustrate to the participants of the 13th Australian Tunnelling Conference 2008 how the insurance industry would like to see the future of tunnelling insurance. Tunnel construction projects have suffered large losses over the years as can be shown from various loss examples and a list of major losses over the last ten to 15 years. Since the consequences of insufficient risk control had to be borne by insurers, these losses have heightened the need for improved and adequate risk management measures so that insurance cover can also in future be provided for this hazardous industry sector. Observations are made as regards to the prevailing trends in the tunnelling industry, which contribute to the increase in risk and have adverse consequences for the insurance industry. To find a solution to this dilemma various options are examined with the suggestion of a Joint Code of Practice for Tunnel Works being agreed by all stakeholders, which would become essential to secure future insurance protection for such project work. The British Tunnelling Society has, in cooperation with the Association of British Insurers, developed such a code, which the International Tunnelling Insurance Group has now adopted for global application in international markets. The content and concept of this code is explained to establish a framework of understanding and applied risk management principles for tunnel works. This initiative also has the support of the International Tunnelling Association and the International Association of Engineering Insurers. The international application of this new code is demonstrated with a few examples, which also includes Australian projects. It is the aim that this code forms in future part of the insurance coverage for tunnelling works in order to put this risk segment on a more sustainable basis. For that reason the insurance industry is seeking the support of all stakeholders of tunnelling construction projects.

Jan 1, 2008

By Enrique Albarrán, Julian Hernández

"In 1942 The “Presa Mixcoac” dam was built, along with 15 other dams, to control the rain fall waterin the mountains west of Mexico City. Mexico City’s population at that time was around 1.5 millionpeople, and the dam was way out of the city."

Jan 1, 2016

By É. Roberge, S. Makni, G. Gagnon, F. Lavoie, A. Faucher

"Feed particle size is an important variable for the primary grinding mill operation. Several commercial vision systems have proven to successfully measure online many types of ores and are used for automatic control. However, due to limitations associated with segmentation algorithms, these systems fail to provide good measurements when the feed is composed of a specific bimodal particle size distribution: very big rocks and a large amount of fine particles. This is typically the case for crushed iron ore. This paper presents a technique to overcome the limitations of existing vision systems by using 3D cameras and appropriate processing methods. It provides online particle size distribution indicators and bulk volume flow rate measurement. It is designed to be very cost-effective, robust, precise, easy to install and to maintain. The 3D system was validated in two iron ore processing plants and the results clearly show that it can be used to optimize primary grinding mill operation where 2D segmentation vision systems fail.INTRODUCTIONFragmentation measurement using digital image processing has successfully been applied in mining and mineral processing operations. Several maintenance and operating applications are already deployed in the industry: Measurement of rock fragmentation after blasting (Maerz, 1999; Palangio, 1999) (Pragyan, 2012) Truck inventory (Palangio, 2005) Monitoring of crusher mantle wear Automatic control of crushers and SAG mills (Bouajila, 2000) (Bartolacci, 2001)Commercial technologies like WipFrag (Maerz, 1999), VisioRock and others proved to be very efficient to precisely measure the particle size distribution of many types of materials. These products are mainly composed of a camera, a lighting system and an image processing system based on a segmentation algorithm. By controlling adequately the lighting conditions and with periodic maintenance on the segmentation algorithm calibration parameters, it is almost always possible to achieve reliable measurements.However, the segmentation algorithm is not adequate when the particle size distribution contains big rocks and a large amount of fine particles. In this case, the area containing the fine particles is accounted as a big rock while big rocks get segmented as multiple smaller sized particles, leading globally to a wrong measurement. This situation prevails for crushed iron ore and coke, among other materials. Figure 1 shows a picture of a material which is typically very difficult to process through segmentation techniques."

Jan 1, 2015

By Kumar A, Mishra N. C

For each tonne of chromite ore mined in Sukinda, approximately ten tonnes of fine overburden material is generated. The overburden typically contains about 30 - 60 per cent Fe2O3, 0.3 - 1.1 per cent Ni, four to nine per cent Cr2O3 and 0.04 - 0.2 per cent cobalt and is being discarded leading to loss of valuable metals and creating environmental pollution. In order to take the advantage of presence of iron, nickel and chromium, the present studies advocate the utilisation of nickel lateritic chromite overburden for production of Ni bearing pig iron through blast furnace extracting maximum iron and nickel from the chromite overburden. The present paper deals mainly with the beneficiation of chromite overburden, sintering characteristics and thermodynamic studies. The beneficiation study shows that a beneficiated concentrate having Fe - 50 per cent and Ni -- 1.1 per cent can be achieved from chromite overburden having Fe - 30 per cent and Ni -- 0.7 per cent. Sintering studies have been carried out with bed height of 300 and 450 mm at a suction of 600 and 900 WG respectively. The results reveal that good quality sinter can be produced from chromite overburden concentrate with a basicity of about 1.0 and coke breeze consumption rate about 16 per cent. In all the experiments, Tumbler Index, Abrasion Index and Shatter Index was found to be in the range of 65 - 70, 4.5 - 5.5 and 85 - 90 respectively. The other parameters namely softening temperature, melt down temperature, reduction degradation test and relative reducibility have also been determined. A thermodynamic analysis has also been carried out to make a technological assessment of the process for the production of alloyed pig iron from chromite overburden in blast furnace which shows that it is possible to produce nickel bearing pig iron in blast furnace using the sinter up to 80 per cent. Techno-economic analysis reveals that this route will yield a substantial profit even after accounting for cost of beneficiation, extra coke, raw materials and extra slag produced.

Jan 1, 1999

Techniques have been developed for the dissolution of a wide range of rocks and minerals by a sodium peroxide sinter process. A olarge number of elements are determined by atomic absorption spectroscopy, and other elements such as arsenic and sulphur are determined by chemical analytical methods. The methods adopted to overcome inter-element and ionization effects on the atomic absorption results are discussed.

Jan 1, 1974

Several factors contributing to the loss of fibre during treatment are a function of the paragenesis of the veins. The occurrence, of magnetite from the cap rock within the veins prevents complete fiberization. There is a marked similarity between these veins and those in the Koegas-Westerberg area of South Africa.INTRODUCTIONAn investigation of the mineralogy of the Wittenoom Gorge crocidolite veins was undertaken in the latter part of 1962 at the request of the Colonial Sugar Refining Co. Ltd. It was anticipated that such a study might reveal the cause or causes of the lack of recovery of some asbestos during beneficiation. Some interesting features of the mineralogy and paragenesis of the crocidolite veins become apparent, but it is emphasized that the investigation is far from complete, as the study did not extend to the field occurrence.The samples examined were selected from the mill and from the untreated ore.GEOLOGICAL SETTINGWittenoom Gorge is situated on the Fortescue River in the Hammersley Ranges of Western Australia and is one of several gorges in these ranges, on the sides of which 'crocidoIite asbestos is known to occur. The Hammersley, Ranges consist essentially of a series of quartzites, shales, ferruginous quartzites and dolomites. These' rocks are part of the Nullagine Formation (Proterozoic) and are usually either horizontal or gently folded. In some 'areas small beds of riebeckite as well as crocidolite are known to occur interbedded in the sequence.Riebeckite is a monoclinic amphibole, the formula of which may be stated as Na2Fe2"Fe2" (OH) 2Si8O22, and crocidolite is a fibrous variety of this mineral. This formula...

Jan 1, 1963

By P. Pyykkö, E. Peuraniemi, J. Järvi, P. V. Latostenmaa, V. Törölä, S. Junnikkala

"Nickel concentrate smelting started in Harjavalta in 1959. First, flash smelting - Peirce-Smith converting route was applied, and the high-grade converter matte was further refined to nickel cathodes. In 1995 the original smelter flow sheet was simplified with the novel DON (Direct Outokumpu Nickel) technology. In Harjavalta with the DON technology, high-grade nickel matte with low iron content is produced in flash smelting furnace directly without subsequent converting stage. The metal values in the smelting slag are recovered in an electric furnace as an iron containing bottom alloy. Main special features in Boliden Harjavalta nickel smelter are smelting of high-magnesia concentrates, the high recoveries of nickel and copper, as well as those of PGM`s and cobalt.Sulfur and dust emissions to air can be seen generally as one main disadvantage of nickel smelting operations. In Harjavalta continuous improvements in environmental performance has been rewarded by minimum sulfur and dust emissions to the environment and working atmosphere. Today Boliden Harjavalta’s nickel smelter is presenting state-of-art-technology at nickel smelting.This paper describes the nickel smelter process and includes recent production and emission data. It describes features required to achieve environmental and occupational hygiene goals and compares environmental performance data to that published on other smelting operations. General description of New Boliden Way is presented and a case example of production stability project is also presented."

Jan 1, 2014

A wide range of drill holes and process streams are sampled for resource estimation, grade control, and contractual purposes in the minerals industry. However, despite the availability of training courses, conferences and both national and international standards on correct sampling practices, it is still surprising how often little attention is given to ensuring that representative samples are collected for analysis. The reason for this is that the responsibility for sampling is often entrusted to personnel who do not appreciate the significance and importance of sampling, with cost being the main driving force rather than whether the sample is representative of the material from which it was extracted. This seriously undermines the precision and accuracy of the analyses subsequently generated and can render the analysis process a total waste of time and money and expose mining companies to serious, potential, financial losses. Company management needs to reverse this situation and ensure that sampling is given the attention it deserves to generate representative samples for analysis.

Jan 1, 2010

By K. Lundholm, A. E. Mäkinen

"Ore grades are declining and getting more complex around the world which not only complicate the ore processing but also produce new type of requirements to manage the produce waste streams. One specifically problematic and increasingly identified element in waste streams produced in mining and metallurgy is arsenic.Arsenic is a compound that has no significant market value, but that needs to be removed from ores, concentrates and other process streams because of environmental or process technical reasons. One example of a removal process is partial roasting of high-As sulfide concentrates, originally developed by Outotec. In this process the arsenic is volatilized in the gas phase and thus separated from the solid material, i.e. the calcine. If the arsenic is recovered by wet methods the process gas is quenched and all arsenic needs to be stabilized in the effluent treatment plant.Outotec has developed ferric arsenate precipitation as a method to produce stabile arsenic residues from wet gas cleaning effluents. Iron based precipitates, when correctly produced, can meet typical landfill criteria measured with different types of leaching methods meant for characterizing the arsenic dissolution behavior from the precipitates.In this paper partial roasting of sulfide concentrates with arsenic volatilization in combination with ferric arsenate precipitation is discussed from the perspective of producing wastes that can meet the stability requirements set by common leaching tests methods, TCLP and CEN. These leaching test methods set the normative landfill requirements for most operations generating arsenic containing wastes. A typical flow sheet of Outotec® Ferric arsenate process is discussed with results showing the importance of correct process control and sequence on producing arsenic containing waste that can meet the landfill disposal requirements."

Jan 1, 2014

This technical note describes a problem with WANG82, a ventilation network analysis programme. The problem was highlighted by Renison Ltd when using the programme on large, complex networks. Under certain circumstances the programme produced incorrect results or failed to converge to a solution.

Jan 1, 1986

By Jonathan Taylor, Irwan Halim, Frederick (Rick) Vincent

The new underground facilities for the LINAC Coherent Light Source project at the Stanford Linear Accelerator Center in Menlo Park, CA, are constructed in very weak sedimentary rock interspersed with uncemented zones. In addition to several 21-footwide (excavated) tunnels, the NATM excavations include a large, 49-foot wide (excavated) cavern, an unprecedented size in this geology. The critical design issues include characterization of the weak rock, some shallow rock cover areas, and very stringent criteria for final invert slab movements within the tunnel. The design also incorporated severe seismic criteria, since the site is in close proximity to the San Andreas Fault.

Jan 1, 2007

In this address I look back over the past 40 years of mineral exploration in New Zealand û essentially the period since the Second World War (ie since 1945). It was the period of my personal involvement, and indeed of the personal involvement of a number of you. Luckily it was aperiod of great interest and activity. In the previous 50 years, virtually nothing had happened, and it is kindest to draw a veil over that period. In the very important earlier 40 years (1855 - 1895) the New Zealand gold rush occurred. That must have been a fascinating, rewarding period, which has been thoroughly documented by better historians than myself. I will simply comment firstly that its mineral explorers (gold-prospectors) were very successful indeed, and found most localities of the minerals they sought, in spite of using very different methods from ours of today. Secondly, they were preceeded by one of Maori exploration, which searched for a much restricted list of minerals, but succeeded in finding virtually every locality we know of today. The explorers of both of these early periods were obviously highly successful, but, in the time available, I must restrict myself to the period since 1945. I am currently editing the effective up-dating of Gordon WilliamsÆ 'Economic Geology of New Zealand' (1974). It covers the last 12 years or so. Many of you are contributing to that volume û both as authors and as referees û and I would like to take this opportunity of thanking you all. Although this new volume excludes the energy field, many of us have been involved in it, and I am therefore including energy minerals in this review, as Williams did in 1974.

Jan 1, 1987

By G. S. S. Raman, M. S. Klima

Coal refuse slurries stored in tailings impoundments can potentially lead to environmental concerns such as effluent seepage, property devaluation, and in extreme cases, dam failures. Pressure filtration offers an opportunity to reduce the impoundment requirements by providing significantly drier solids. A full-factorial design was used to study the effects of temperature and pH on dewatering a refuse slurry obtained from a coal preparation facility in Pennsylvania, USA. The experimental results indicated a strong effect of temperature on cake moisture as the cake moisture after about 2800 s was 22% at 43 °C and only 36% at 10 °C for tests conducted at pH 3. ANOVA results confirmed the statistical significance of pH, temperature, and their interaction effect. Also, the results showed no significant differences between the tests conducted near neutral and alkaline pH values at low and ambient temperatures. On the other hand, Tukey’s test indicated higher reductions in cake moisture at higher temperatures for lower pH values. This study affirms the need to monitor and control the pressure filtration process as throughput could significantly vary with changes in temperature and slurry conditions.

By G. S. S. Raman, M. S. Klima

Coal refuse slurries stored in tailings impoundments can potentially lead to environmental concerns such as effluent seepage, property devaluation, and in extreme cases, dam failures. Pressure filtration offers an opportunity to reduce the impoundment requirements by providing significantly drier solids. A full-factorial design was used to study the effects of temperature and pH on dewatering a refuse slurry obtained from a coal preparation facility in Pennsylvania, USA. The experimental results indicated a strong effect of temperature on cake moisture as the cake moisture after about 2800 s was 22% at 43 °C and only 36% at 10 °C for tests conducted at pH 3. ANOVA results confirmed the statistical significance of pH, temperature, and their interaction effect. Also, the results showed no significant differences between the tests conducted near neutral and alkaline pH values at low and ambient temperatures. On the other hand, Tukey’s test indicated higher reductions in cake moisture at higher temperatures for lower pH values. This study affirms the need to monitor and control the pressure filtration process as throughput could significantly vary with changes in temperature and slurry conditions.

G. R. Compton (Gold Mines of Kalgoorlie (Australia) Ltd., Fimiston, W. A.) : In congratulating Mr. Hooker upon his resume of Mr Parry's paper I have in mind the fact that he carried out the research into pipe pressures. Hydraulic filling as practised in Kalgoorlie has created world wide interest, with these pressures and percolation being vital points.Early in the 1950s, representatives of the Kolar field were conduGted over the local mines where stopes at depths below 2,000 ft were being filled. The problems of pipe pressures were their main consideration since depths of up to 10,000 ft were envisaged.Mr Krishnaiah and Mr Murthy from the same field are with us today and perhaps we may hear of their experiences with depths of 6,000 ft and long lateral lines.J. Holly (Lake View and Star Ltd., Fimiston, W.A.): There is one phase, which I would like to mention myself, that has been very evident in Kalgoorlie operations. That is, we do not get the percolation properties that are obtained on many other fields in the world, and our tendency here has been to assess the quality of our fill more by its settling rate, i.e. the rate at which we can draw off clear water at the surface of the filling levels, rather than the rate that this water percolates down through the fill before it consolidates.We are tending now to measure the quality of our fill as a settling rate rather than as a percolation rate.Americans talk about percolation rates being the important property: If anyone has any experience on operating with fills with different percolation rates, I think their views would be very interesting to the meeting art this stage. Mr ...

Jan 1, 1965

By A Jäger, J L. Lett, J Rachocki and B Mobilio

The Newcrest Mining Limited Cadia East Panel Cave mines near Orange, New South Wales, Australia commenced production 1200 m below the surface in May 2014. Understanding the mine-wide impact caving had on excavation stability was a primary objective to ensure a safe working environment as production ramped up in the Panel Cave 1 operation and establishment activities were implemented in Panel Cave 2. The impact of cave interaction between Panel Cave 1 and Panel Cave 2 and establishing monitoring systems to assist mine planning and production as both caves joined is explained in this paper. Monitoring tools such as a microseismic system, open holes, HI-cells, extensometers, fibre optic sensing, cave markers, closure monitoring, underground observations and damage mapping were used to characterise the performance and position of the cave back. The data and observations collected were compared to predictions from numerical and empirical methods and used to calibrate the numerical models for forward prediction and to develop site empirical design tools. The results and methodology for monitoring deep high-output caves are the key discussion points in this paper.CITATION:Lett, J L, Jäger, A, Thornhill, T, Rachocki, J and Mobilio, B, 2016. Geotechnical challenges in cave monitoring – a modern approach, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 203–216 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By Robert B. Parsons

"The tax reform process marches on. The December 16, 1987 measures tabled by Finance Minister Michael Wilson represent one more step toward the objective of total reform of Canada's income and sales taxes. While the income tax changes are taking shape, much work still needs to be done on the sales tax side of the coin.IntroductionOn December 16, 1987 Finance Minister Michael Wilson tabled measures to implement the changes to Canada's income tax system that were proposed in the June 18, 1987 White Paper on Tax Reform. The measures were set out in a Notice of Ways and Means Motion; draft legislation relating to preferred shares, research and development expenditures; and draft regulations regarding capital cost allowance, certified films, flow-through shares, and the resource sector. The reaction of the government to the recommendations made by the Finance and Economic Affairs Committee Report on Tax Reform (the Blenkarn Committee), the Report of the Standing Senate Committee on Banking, Trade and Commerce and through consultations with interested groups and organizations, business, labour and individual Canadians is set out in a booklet of supplementary information.The basic features of the reformed income tax system set out in the White Paper remain. However, a number of significant changes have been incorporated in the Notice of Ways and Means Motion and other material. The following comments address those area s where changes have been made to the original White Paper proposals."

Jan 1, 1988