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By F. -J. Wodopia

Sustainability of energy supplies has been an issue of general interest for a long time. Whilst in the past the continuous productive use of natural commodities was in the fore, its compatibility with the environment and climate and ultimately also social aspects have recently gained more and more attention. Today many discussions focus on the climate compatibility of individual options to act. Fossil fuels, in particular coal and lignite, are generally challenged because coal use makes a significant contribution to global man-made CO2 emissions. The drastic increase in the consumption of fossil fuels is not explained by the fact that coal utilisation technologies are not or cannot be sustainable but rather by the growing world population and the endeavours numerous national economies trying to catch up economically. Coal is the world’s No. 1 fuel and, in the view of many experts, will keep this position also in the foreseeable future. The access to its deposits plays a significant role for the economies of the emerging countries. Consequently the aspects of energy security and economic efficiency need to be considered at eye level with climate compatibility. In Germany, however, the public acceptance of fossil fuels and of large industrial projects is in the focus of attention.

Jan 1, 2011

By V. Labiouse, P. K. Kaiser, F. Descoeudres, F. Rojat

In this paper some failure phenomena observed in the crossing of brittle rock formations at the Lötschberg base tunnel are presented. A brittle failure criteria, recently developed by Canadian researchers, is applied through finite element calculations together with a semi-empirical failure criterion, to explain these behaviours. Good agreement is found between predicted and observed failures at the tunnel walls. This study also shows some of the limitations of this approach. Dans cet article sont présentés certains phénomènes de rupture observés durant la traversée de zones de roches fragiles lors de l’excavation du tunnel du Lötschberg. Un critère de rupture développé récemment par la recherche canadienne est utilisé à travers des calculs par éléments finis. En parallèle, les résultats sont comparés avec ceux d’un critère semi-empirique. Au niveau des parements, l’ampleur des ruptures observées est assez proche des résultats de calcul. Cette étude a également permis de mettre en avant certaines limites de l’approche choisie. In diesem Artikel werden verschiedene Brucharten dargestellt, die bei der Durchfahrung von sprödem Gestein im Rahmen des Ausbaus des Lötschberg-Basistunnels beobachtet wurden. Zur Erklärung des vorliegenden Verhaltens wurden die erst kürzlich in Kanada entwickelten Theorien zur Beschreibung von Sprödbrüchen herangezogen und bei der Berechnung mittels der Finite-Elemente-Methode und eines semi-empirischen Kriteriums angewendet. Die so vorhergesagten Versagenszonen an den Tunnelwänden stimmen mit den Beobachtungen gut überein. Die Studie hat auch dazu beigetragen, die bei der Anwendung des Lösungsansatzes angetroffenen Schwierigkeiten aufzuzeigen.

Jan 1, 2003

By L O. Filippov, Q Dehaine

Variographic analysis, a classical tool from the Theory of Sampling (TOS), can address practical situations with multiple variables; however, its application has very often been limited to one variable at a time. Recent developments have shown the benefits of using multivariate approaches for variographic characterisation of a set of variables instead of considering individual variables sequentially. Among these approaches, the multivariogram has been revealed itself to be a powerful tool when the overall time-variability of a process must be summarised in terms of a large set of properties (variables) to assess its true global variability. However, even when choosing the properties of interest carefully, the resulting global variance obtained with this approach may be very high. In particular, some variables that contribute to a major proportion of the global (multivariate) variability could be less important for the process performance than others having a lower variability. To address this issue, a new approach is proposed, combining the multivariogram with process modelling and multivariate data analysis methods such as partial least squares (PLS) regression from chemometrics. An example from the mineral processing industry is presented, for which the process performance could be linked to key process variables (sensor data) using the PLS regression. Once introduced in the multivariogram equation, PLS model parameters (loading-weights or regression coefficients) can be used to weigh the variables according to their relevance for the process. In addition, this also permits characterisation of process performance variability with time using only the process input variables and a weighted metric according to the PLS regression model. Ultimately, this method helps to find an optimised sampling procedure in terms of frequency, sampling mode and number of increments according to the actual overall process performance. This approach has potentially many applications in the mining, feed and food, pharmaceutical or any other industry for which it can be used to reduce risks and ensure a better use and management of resources.CITATION:Dehaine, Q, Filippov, L O and Glass, H J, 2017. Optimising multivariate variographic analysis with information from multivariate process data modelling (partial least squares regression), in Proceedings Eighth World Conference on Sampling and Blending , pp 381–390 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

This manual provides instructions for installing, operating, and maintaining a protective canopy on the Galis Mfg. Co. face drill. The instructions are based upon an actual installation made in the mine on face drill model 460-S. The parts list and engineering drawings for the protective canopy are included at the end of the manual. And a discussion of some alternative design concepts is also included. The manual can also be used for retrofitting other face drills with similar protective canopies. Skilled mechanics can determine if the instructions herein would be applicable to the other face drills and can determine any necessary modifications if they are not.

Jan 1, 1973

By Leon Lorenzen, Victor E. Ross, Anton W. Kleingeld

"Key to successful innovation, whether at organization, industry or national level, is the alignment and utilization of resources in the most appropriate and efficient way. Innovation needs to be directed strategically, and it needs to be auditable in a systematic and integrated fashion. In the light of these considerations, this paper describes the construction and use of a topographical map of the innovation landscape of an organization. The purpose of the map is to provide a holistic view of the key factors that enable innovation (the so-called 'landmarks'), how well they are aligned to support a particular type/nature of innovation in the organization (e.g. radical vs. incremental innovation), and to identify possible gaps between actual and sought performance.The landscape covers four domains that influence innovation - the attributes of the individual, the organizational context in which he/she functions, the business environment (the market / industry in which the organization is operating) and the external environment. The significance (importance) and height (performance) of the landmarks in supporting and enabling innovation within the organization is determined by means of a self-appraisal audit. The topography of the landscape derived thus is subsequently interpreted in terms of the organization's particular innovation strategy and environmental context."

Jan 1, 2003

By W. E. Field

In the Coast Mountains approximately 110 miles north of Vancouver, the gold mine of Bralorne- Pioneer Mines Ltd. lies at an elevation of 3500 ft. The deepest or 41 level in the mine is at an elevation of 1400 ft below sea level, and the rock temperature on this level is 122.5°F. The thermal gradient is 1 "F increase in temperature for each 67.5 ft increase in depth. The mine produces between 500 and 600 tons per clay, utilizing an adit two internal shafts, and one service shaft from surface. The Queen shaft, extending from the 26 to the 41 level, IS the deepest, and most production now comes from this area. Stoping in by cut and fill using mill tailing hydraulic backfill.

Jan 12, 1963

By Charles Will Wright

This paper is one of a series dealing with mining problems and summarizing the data contained in the Information Circulars on individual mines that have been prepared by the managers or superintendents and published by the Bureau of Mines. The purpose of this paper is to present the problems encountered in the development of an efficient mine organization and to show the means used by certain mining companies in promoting efficiency. There is also a discussion of the advantages and disadvantages of the various systems of paying and handling labor and a description of their application at the individual mines.

Jan 1, 1932

Introduction The science of geometallurgy requires that ore characterization be performed holistically, that is, with consideration of ore quality on plant performance and product quality. Geometallurgy, by definition, requires knowledge of geology, mineralogy, extractive metallurgy and pyrometallurgy. Examples of the ore characterization challenges for the geometallurgist in the production of iron ore pellets from low-grade Proterozoic iron formation are presented here. Ore Characterization Ore characterization, the quantifying of mineralogy, grain size and the texture of ores, is an often overlooked tool in improving process efficiency. Some mineral related problems are not unique to the production of iron ore pellets; e.g. the problems caused by expanding clays in flotation. The negative impact of carbonate minerals in the ore on pellet productivity and pellet quality are unique. The long and complex geologic history of Precambrian iron formations contribute to modifications of grain size and the introduction of complex textures.

Jan 1, 2007

By L. M. Anisdahl

Ventiflex is a flexible ventilation duct system with a global market within mine and tunnel ventilation. The system is distributed in a wide range of qualities and dimensions. It is very important that ventilation systems are designed correctly in mines and tunnels. An incorrectly dimensioned system might result in bad air quality and too high costs. The objective of this study has been to assess some important design parameters for ventiflex comprising the friction loss factor for the duct wall itself, as well as the shock loss factors and the leakage factors for the different couplings systems. This has been obtained by carrying out a large scale experimental program on ducts with all the three different couplings: Velcro, zip and steel-ring. Pressure profiles and air flow rates have been measured, and based on these data the different factors have been calculated. The following results have been obtained: A friction factor l = 0,012 (K = 10) for the duct wall, a shock loss factor z = 0,0125 for velcro- and zip couplings, a shock loss factor z = 0,005 for steel-ring couplings, and a leakage factor f* = 0 mm2/m2 for all three coupling types. The latter result proves that no leakage is possible for a correctly installed duct with proper alignment. The results also confirm that ventiflex complies with class S, or better, according to the SIA-norm. However, whether ventiflex should be designed as class S, A or B according to the SIA-norm, depends on the particular application.

Jan 1, 2009

By A Hoyle, P Walker, D Bennett

The Phu Kham copper-gold operation located in Laos People’s Democratic Republic (PDR) is owned and operated by Phu Bia Mining Limited. PanAust Limited, based in Brisbane Australia, holds a 90 per cent interest in Phu Bia Mining Limited, with the remaining 10 per cent held by the Government of Laos PDR.The 12Mt/y copper-gold concentrator at Phu Kham commenced production in April 2008. Flotation copper and gold recovery from commissioning was consistently poor, due to the high levels of pyrite and problematic secondary and oxide copper species and non-sulfide gangue.The low recoveries of copper and gold from Phu Kham were recognised during the feasibility study design phase. A bulk sulfide flotation regime in roughing produced high recoveries, however a large capacity cleaning circuit was required and there was risk of not meeting saleable concentrate grade specifications. The installed design offered a capital efficient compromise to ensure that a concentrate grade of 24% copper could be achieved at acceptable recoveries.Incremental improvements in copper recovery were achieved by 2011 through conversion of conditioning cells to flotation cells in both roughing and first cleaning and increased cleaner capacity through the installation of a Jameson cell. In 2012 the Phu Kham Upgrade Project was commissioned to increase mill throughput, along with additional rougher and cleaner capacity to increase residence times at the nominal 16 Mt/y throughput. The marginal reduction in primary grind size due to the additional ball milling power also provided a small recovery improvement.This paper presents the development, design, implementation, and performance of the Increased Recovery Project commissioned in April 2013 which targeted the major causes of copper loss from the circuit. Based on fundamental and detailed test work and mineralogical analysis of concentrator streams, an optimised design was developed which has increased copper and gold recoveries by over 5% and 10% respectively. The Increased Recovery Project has positioned the concentrator to process high pyrite ores that were previously considered untreatable, and opened further opportunities for maximising flotation recovery by de-bottlenecking plant regrind and cleaning capacity.CITATION:Hoyle, A, Bennett, D and Walker, P, 2015. The increased recovery project at the Phu Kham copper-gold operation, Laos PDR, in Proceedings MetPlant 2015, pp 246–265 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By A. V. Pavlov, A. V. Dubachev, K. L. Kossyrev

The purpose of the given research was to investigate the possibility of high-carbon ferrochromium refining to remove harmful impurities as a result of metal treatment by slag mixtures on the basis of the CaO-MgO-SiO2system. The final conclusions were drawn from experimental results. It was shown that the treatment of high-carbon ferrochromium by SiO2-MgO-CaO slag mixtures with additions of chromium sinter or iron-ore concentrate removes carbon, sulphur and phosphorus from the metal. A mechanism of phosphorus removal from a melt to a gas phase is proposed.

Jan 1, 2004

By D. Harrington

The record of fatalities from mine explosions during the past 2 fiscal years has been anything but encouraging; more men were killed by explosions (379) than were killed from the ante cause during to' preceding 6 years combined (368). The reason for the large increase in the number of explosion fatalities during the past 2 years as compared with the previous 6 years is not entirely clear. In some instances, there has been laxity in the enforcement of State mining laws; in others, both workers and operating officials is have failed to observe recognized precautionary measures to prevent explosions. In many of the explosions that lave occurred within the asst few years in mechanized mines it has been evident that speed of operation and a demand for maximum tonnage at minimum cost resulted in neglect of ordinary safety measures.

Jan 1, 1942

By S. C. Rhoads

The Bureau of Mines is investigating low-chromium alloy substitutes for type 304 stainless steel (type 304 SS). The purpose of the research is to reduce the chromium content in austenitic stainless steels used for corrosion-resistant applications. Nine Fe-9Cr-12Ni alloys containing additions of 0 to 5 pct Mo, 0 to 2 pct V, and 0 to 2 pct Cu were selected for evaluation. All of the experimental alloys containing 5 pct Mo and an alloy containing 2Mo-2V-2Cu possessed structure and tensile strengths similar to those of type 304 SSe Alloys containing SMo-2V and SMo-2V-2Cu had ac-ceptable welding properties as measured by the Varestraint test. Alloys containing at least 2 pct Mo had cQrrosion resistance comparable to that of type 304 SS in solutions of nitric acid, phosphoric acid, acetic acid, and citric acid. In chlorides, all the experimental alloys were susceptible to localized corrosion and stress corrosion cracking similar to that of type 304 SSe The corrosion properties were established by weight-loss tests, electrochemical polarization tests, and stress-corrosion cracking tests. An Fe-9Cr-12Ni-SMo-2V alloy and an Fe-9Cr-12Ni-SMo-2V-2Cu alloy had a combination of welding properties, tensile properties, and corrosion resistances that were most comparable to those of 304 SS.

Jan 1, 1984

By Rimas Pakalnis, Andrea M. Ouchi, Thomas M. Brady, Mary M. MacLaughlin, Cristian Caceres, Paul Hughes

A major focus of ground control research presently being conducted by the Geomechanics Group at the University of British Columbia, Canada, in conjunction with the National Institute for Occupational Safety and Health’s (NIOSH) Spokane Research Laboratory, is the development of design guidelines for underground mining within weak rock masses. The study expands upon the span design curve for man-entry operations and the stability graph for nonentry operations developed at UBC by extending the application to weak rock masses. The original database has been augmented by weak rock mass information from mines throughout the United States, Canada, Australia, Indonesia, and Europe. The common factor in all of these mines is the presence of a weak back and/or walls. This paper expands on the North American database and how the design curves have been employed at mining operations throughout the world. The definition of a weak rock mass for this study has been defined as having an RMR76 under 45% and/or a Q-value under 1.0.

Jan 5, 2007

By Faruk Oksuz, Clay Haynes, Miguel Sanchez, Patrick Finn, Roger J. Maurer

The Milwaukee Metropolitan Sewerage District’s (MMSD)’s challenges of basement flooding and wet weather sewer overflows are being creatively addressed with the Northwest Side Relief Sewer tunnel. The $132 million, 20-foot diameter, and37,740 feet long conveyance and storage tunnel excavation in dolomite at depths reaching 165 feet below ground surface has been successfully completed within13 months in April 2004. This paper includes Owner’s perspective on the overall project, and the design and construction details by the Designer and the Contractor. The project contract documents included a comprehensive Geotechnical Data Report and the Geotechnical Baseline Report.

Jan 1, 2005

By R L. Langak, R A. Heins

The use of differences in specific gravity between minerals to separate them has long been utilized in the extractive industries. The environmental and cost benefits of the commercialized forms of these processes are well understood and widely used. Gravity concentration is used inter alia in the primary beneficiation of gold, diamonds, coal, tin, ferrous metal ores and andalusite. The potential for economic loss due to poor performance of these gravity processes is significant, but diverse in manifestation and regular process monitoring can prevent or at least reduce these losses. The measurement of performance of gravity processes has always presented a challenge, due primarily to the masses of material involved and the physical nature of the processes, generally typified by long reporting time, and hazardous materials (such as Tetrabromoethane) for float and sink type tests. The development of density tracers has improved this situation, however recovery of these tracers from the process streams created the next set of challenges, requiring significant manpower to physically remove tracers from product dewatering screens. Additions to these tracers (magnetic or x-ray fluorescent) eased the recovery mechanism issues but made them much more expensive to produce, hence operators became concerned about losses during process testing. In addition, magnetic recovery of smaller size tracers by a magnet suspended above a loaded screen panel is still problematic. The development of new low cost magnetic tracers has improved statistical significance of tracer tests, as the tracers themselves can be bought and used in much larger quantities, whilst still remaining economically viable. Coupled with the development of effective magnetic recovery technology, such as the Gekko MagScreen, for even fine sized tracers, on-line, continuous tracer testing is now becoming a reality. Whilst the development of high technology radio frequency detection tracer systems continues, enabling the real time measurement of the process and interpretation of results, miniaturization and recovery of these tracers, which is critical given their costs at present, remains an issue. Keywords: Gravity, process measurement, tracers, magnetic recovery

Jan 1, 2006

By S M. Aminossadati, R Bagherpour, F Hasheminasab

Mine ventilation is an essential part of underground mining operations used to provide fresh and cool air, as well as to dilute and remove contaminants from the work environment. This paper presents an overview of the ventilation and gas management systems in one of the underground coalmines in Iran: Parvadeh_1 mine. The mine is located in the Tabas coalfield in the South Khorasan province. It is the only fully mechanised mine in Iran utilising the longwall retreat technique. The mine produces 1.1 to 1.3 Mt of coking coal annually. The mine ventilation system currently utilises two 630 kW exhaust surface fans. The gas management system includes surface to in seam (SIS) predrainage boreholes. The underground mine is equipped with an underground gas reticulation pipeline that is connected to a surface plant for the production of methane gas. This study shows that the ventilation and gas management systems of the Parvadeh_1 mine are in line with the standards of Australian underground mines.CITATION:Hasheminasab, F, Aminossadati, S M and Bagherpour, R, 2017. An overview of ventilation and gas management systems in an underground coalmine in Iran, in Proceedings Australian Mine Vent Conference 2017, pp 41–46 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By Susanna G. de Jager, Francis W. Petersen

"To enable the prediction of reagents suitable for fine coal flotation, it is necessary to develop a methodology applicable to different South African coal types. Statistical confirmation of the applicability of this methodology is important to avoid recommendation of reagents on a trial and error basis.The study included 5 coal samples from different collieries and included Highveld seam 3 and 4 coal (as one sample), Waterberg coal (zone 10 -11), Highveld seam 5 upper coal and Witbank seam 2 and seam 4 coal. Seam 3 and 4 (mixture) coal, Waterberg and the seam 5 upper coal were all found to be vitrinite rich coals. The coal characterisation study included petrographic analysis, proximate analysis, float-sink analysis, oxygen-containing functional groups, surface extraction, flotation release analysis and contact angle measurements. Flotation tests were used to validate expectations from the characterisation of the coal samples.RESULTSThe flotation data indicated that all of the coal samples were amendable to froth flotation. The best results were obtained with the Witbank seam 2 coal and the poorest flotation with Syferfontein seam 5 coal. The flotation tests showed that the best reagents to float all of the coal samples studied were iso-decanol and dodecene. These reagents produced flotation products that were near to the release curve, which are the optimum flotation results (obtained when using iso-paraffin as collector). Dodecene resulted in low ash products and iso-decanol in high yield products."

Jan 1, 2003

By Yuexin Han, Zehong Wang, Fujia Yu, Wanzhong Yin, Xinchao Wei

Bauxite is the main raw material in alumina and refractory industries. China has plentiful bauxite resources, most of which belong to the diaspore type bauxite with characteristics of high aluminum content, high silicon content and low ratio of alumina and silica (A/S). The resources with A/S 4-7 account for more than 60% of the total resource reserves of bauxite. Therefore improving the A/S through bauxite desilication is the key task of bauxite concentration in China. Normally the grinding fineness of 80-90% - 0.074mm is required in the bauxite flotation process. Thus fine grinding of bauxite ores is necessary, which leads to the high energy consumption. In the meanwhile, bauxite ores are easy to produce slime during grinding processes. The large amount of slime produced in fine grinding greatly worsens the process environment of bauxite flotation, affects the separation performance and results in the loss of metal. Also, fine grinding makes the flotation concentrate difficult to dewater, while the water content in the flotation concentrate must be removed by distillation in the subsequent alumina dissolution process, causing the increase of energy consumption and cost in the production of alumina. In this study, the selective grinding behaviors were examined with Henan Bauxite as feed. Separation of alumina and silica at a coarser grinding fineness was achieved and new route was explored to enhance the desilication in bauxite concentration to improve the A/S of bauxite concentrate.

Jan 1, 2003

By R. P. Jensen

This is a sampling of the papers presented at the conference, the proceedings can be bought from the SAIMM Arbitrary Lagrangian Eulerian (ALE) computational techniques allow treatment of gases, liquids and solids in the same simulation. ALE methods include the ability to treat shock waves in gases, liquids and solids and the interaction of shock waves with each other and with media from one of the other categories. ALE codes can also treat explosive detonation and the expansion of the explosive gases and their interaction with air and solids. ALEGRA is a 3-D ALE code that has been developed at Sandia National Laboratories over the past few years. ALEGRA has been applied to a 2-D simulation of presplitting using decoupled explosives in rock blasting with very interesting results. The detonation of the explosive at the bottom of the hole sends a shock wave up the borehole driven by the explosive gas expanding into air. The explosive gas compresses the air against the stemming column where it rebounds and recompresses at the bottom of the borehole. This type of ringing takes several cycles to damp out. The explosively induced expansion of the borehole is also treated by ALEGRA as well as the shock wave imparted to the rock. The presentation of this paper will include several computer animations to aid in understanding this complex phenomenon.

Jan 1, 2000