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By Axel Preusse

On the basis of the Law on Financing Hard Coal Mining dated 28 December 2007, the subsidized German hard coal mining industry will be shut down to the end of the year 2018 in a socially acceptable manner; in 2012 this decision will be reassessed. Even after the abandonment of all mining activities subsequent burdens are inevitable. In this paper, the possible long-term effects resulting from a mining industry history, which is spanning more than 200 years, and their possible consequences are pointed out, in particular in connection with the abandonment of mine water drainage measures which is economically meaningful in the long term. According to the decision situation as it presents itself today, this point in time will be far beyond 2018. In preparation for this, an action framework is to be developed in areas possibly affected.

Jan 1, 2008

By H. Venkatesh, Balachander R.

This article discusses the method that was adopted for controlling damage to rock mass while excavating an underground powerhouse cavern at Tala Hydroelectric Project. It discusses in detail the near field vibration studies carried out and the safe vibration levels established for that rock mass condition.

Jan 1, 2006

Jan 1, 2000

By Sean Gallagher

Humankind's interest in measurement of human physical strength probably dates to the first humans. At that time, life was truly a struggle in which the fittest survived. To a great extent, fittest meant strongest. Interestingly, current interest in human physical strength in the workplace stems from 1970-1980s vintage research demonstrating that persons with adequate physical strength are less likely to be injured on physically demanding jobs. Survival in many modem workplaces may still be a case of survival of the strongest. There is, however, a flip side to this issue - that persons with limited strength are more likely to be injured on "hard" jobs. To address this problem, we can apply what we know about physical strength to job design. "Hard" jobs can be redesigned to be within the physical strength capability of most people. Since physical strength is important to these jobs, we must find ways to quantify it through testing. This publication concerns human physical strength testing. Its purpose is not to recommend any particular type of testing, but rather to describe the types of testing available and their uses. It is up to each individual user of strength testing to decide which testing technique is most appropriate for his or her particular application. This booklet discusses four types of strength testing: isometric, isoinertial, psychophysical, and isokinetic.

Jan 1, 1998

To the industrial geologist, as wen as to the general or historic geologist, the possession of a reliable key to the true order or sequence of the stratigraphy or position of the various upper rocky envelopes of the earth's crust, is, equally, a desideratum of the utmost importance. Of similar value to the two groups of students is the possession of facts which throw light upon the relationships which subsist between the puccessive rock formation of different countries, especially between countries lying close to each other, or within the same great geographical division.But there is necessarily a fundamental distinction which marks the respective limits of the field of observations of the industrial geologist, and the purely historic interest of the general geologist. The former has a more definite though less extensive scope. The scope of the latter is wide and indeterminate. In short, the observations of the industrial geologist are, 'from a commercial or economic point of view, of a more practical character, and are, therefore, intentionally restricted to the study of all geological questions which throw light upon the rocks which yield products of economic value and only include the study of the character and history of other rocks, in so far, as they afford aid to the more perfect comprehension of the best manner in which materials of economic value are likely to be sought, and the best means whereby these products may be secured for the material advantage of the community. The motive of the general geologist-in most cases-is a love of the study of some particular branch or province of the geological field, and the fascination of opening a new volume in nature's library, and the hope of extending the realm of knowledge, however slight, are often sufficient, as a motive, to enlist the energy and life's devotion of the true brethren of the hammer, irrespective of considerations regarding the commercial utility of the pursuit.

By C. C. Clark, P. W. Patton, B. M. Stewart

Handling materials in underground mines continues to be a major safety problem. To help reduce materials-handling injuries, researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health are investigating those materials-handling tasks in underground mines that appear to generate a high number of injuries. Data from the Mine Safety and Health Administration for the years 1989-1999 were studied to find out if there were any trends in materials-handling accidents and if so, to determine what tasks were involved and the sources of injuries. Several underground coal and metal mines were visited to document innovative materials-handling technologies. Considerations for safety training and mechanization needs for continued reduction in materials-handling injuries are described.

Jan 1, 2002

SEVERAL serious accidents, which had occurred owing to the platman leaving the plat without first withdrawing the "chairs" from the shaft, set the writer scheming to devise a mechanically operated system which would obviate such accidents and be "fool-proof". It was obvious at the outset that some means of indicating to the engine-driver by the movement of the "chairs" themselves, whether they were "in" or "out" of the shaft, was necessary.An arrangement of signalling similar to railway semaphores was considered, but was rejected owing to the difficulties accruing from the large number of communicating wires which would be required down the shaft-viz., 2 for each level. After several experiments, a comparatively simple and efficient electrical system was devised, and which is covered by Commonwealth Patent TO. 10,402.One of the chief features of the apparatus is its simplicity, and its strongest point is the fact that both the engine-driver and platman receive visual indication of the position of the "chairs." The arrangement consists of a miniature coloured glow lamp, one for each level of each shaft compartment, arranged and placed beside the numbers and arrows corresponding to the various levels, on the winding engine indicators. Also a large indicating glow lamp is installed at each compartment in the various levels, in proximity to the levers for operating the "chairs." Upon operating the various levers for the "chairs," an electrical current...

Jan 1, 1909

By V. Velicka, J. Ptacek, R. Snuparek, P. Konecny, G. Takla

Coal mining in Ostrava-Karvina coalfield is being accompanied by rockbursts. 82 rockbursts occurred within the period between 1990 and 2002. Natural and technological factors from these rockbursts were collected and analysed. They confirmed that rockbursts are complex geomechanical events and that the relations between co-acting technological and natural factors are very complicated. Der Abbau in dem Ostrava-Karvina Steinkohlenrevier wurde von Anfang an durch Gebirgsschläge begleitet. 82 Gebirgsschläge in dem Zeitabshnitt von 1990 bis 2002 erfolgten. Die Angaben über natürliche und technische Faktoren der Gebirgsschläge wurden gesammelt und analysiert. Es wurde bestätigt, dass die Gebirgsschläge komplexe geomechanische Phänomene sind und dass die Beziehungen zwischen den zusammenwirkenden Faktoren sehr kompliziert sind. L´abattage d´houille dans le Bassin houiller d´Ostrava-Karvina est accompagnée par les coups de terrains. 82 coups de terrains s´étaient produit dans la période entre 1990-2002. Les données sur les facteurs naturels et techniques ont été ramassées et analysées. Les résultats ont corroboré que les coups de terrains sont des phénomènes géoméchaniques complexes. Les relations entre les facteurs techniques et naturels coopérants sont très compliqués.

Jan 1, 2003

By E. L. Singleton

This Bureau of Mines investigation was initiated to study and establish some of the chemical and physical characteristics of the condensed Mno-Si02 system. To prevent oxidation of the manganous ion, I atmosphere of purified helium was used in the furnaces. Solidus-liquidus curves and invariant points were established from melting-point determinations and were supplemented from data obtained by the static-quenching method. Experimental findings and data are for the intermediate compounds of tephroite and rhodonite with their respective eutectics represented at 25.5 and 37.2 weight-percent silica. Tephroite melts congruently at 1,347° C., and rhodonite melts incongruently at 1,286° 8.. A metastable transformation was determined to exist at the 1,347° C. isotherm, the congruent melting point of tephroite. A composite X-ray-diffraction pattern was formulated for synthetic rhodonite. This investigation contributes fundamental data leading toward a better understanding of the more complex slag systems.

Jan 1, 1962

By L. Boyd, A. Charland, G. Potts, D. Fragomeni, N. O. Lotter

"The Raglan orebody and concentrator has been the subject of study in Process Mineralogy at Falconbridge since 1998. (Lotter and Tuzun, 1998) The orebody is classified into three distinct textural groups, or end members. These are referred to as disseminated, net-textured, and Massive Sulphides, and differ in terms of mineral grain size, nickel grade, hardness, and mineral association. In this paper, it will be shown that the sampling and characterisation of each end member on an individual basis develops a higher-level understanding of the processing requirements and behaviour of the mixture of ore as presented to the mill.The end members have been used in robust prediction of recovery at various grind size p80 from laboratory scale High Confidence Flotation Tests. Weighted mean mixtures of the end members have been mathematically combined to determine impact of textural distribution on metallurgical performance as a function of grind size.The ore end members also vary in hardness and breakage mechanism and have been used to model throughput capability for existing, optimized and retrofit grinding circuits. This modeling has provided a range of expected throughputs as the relative proportions of each end member varies.Finally, the differing grinding requirement per end member has led to the development of grinding and flotation strategy that increases rougher flotation recovery and provides flowsheet options for a concentrator expansion. This leads to further understanding of the plant performance as a function of ore mixture."

Jan 1, 2005

By Seong-Taek Yun, Chil-Sup So, Seung-Jun Youm

The greisen-bordered quartz veins are spatially, temporally and genetically associated with a late Cretaceous granite intruding an early Palaeozoic, limestone-rich formation. Paragenetic data indicate three stages of hydrothermal mineralisation, the first typically in or within 500 m of the granite stock and showing vertical zoning between deeper Mo and higher W, the other two more abundant in the upper and outer parts of the mineralised area. Fluid inclusion and stable isotope data indicate that hydrothermal veins formed over a temperature range of 120-395 degrees C from low-salinity fluids. Early wolframite and molybdenite deposition in stage I occurred at temperatures of 300-395 degrees C from magma-derived, low-salinity, CO2-rich fluid, mainly as a result of fluid boiling and associated CO2 effervescence. Progressively larger volumes of local meteoric water entering the system led to the successive deposition of scheelite in stage I vugs, stage II base-metal sulphides and stage III fluorite-carbonates. Remobilisation of W and its later deposition of scheelite in the outer and shallower portions of the system occurred at 215-275 degrees C and stage II and III mineralisation from lower-temperature fluids that became progressively lighter in stable isotopes. It is concluded that the influx of meteoric water increased with distance from the cooling pluton

Jun 18, 1905

By David M. Spatz

The way people interact, collaborate, learn and improve can have a profound impact on a company’s efficiency, performance, productivity and return on investment. This is the motive behind corporate efforts today to replace the traditional hierarchical structure with team-oriented organization. The increased importance of communication and collaboration during the past 20 years has been propelled by rapid advances in technology and increased availability of information. Companies must take advantage of the information that is required for competitive performance and for the continued production of quality products. So it is essential that outstanding communication, cooperation and collaboration take place among multidisciplinary specialists assigned to work together to solve common problems and achieve common goals. Companies are searching for ways to increase knowledge transfer and learning, particularly among people who work on related topics. This will improve efficiency and quality and reduce redundancy and costs.

Jan 1, 2000

By da Silva C A, Tenorio J. A S, de Assis R M, de Oliveira J R

For Fe-Mn alloy production, two reactions are responsible for this process: the MnO reduction in the slag and the carbon dissolution in the bath. The smelting-reduction process has been studied as alternative route to be used to produce alloy so as steel. This technical paper presents some initial studies to be used to determine the main ways that one can have for the mechanisms for this reaction. The limited factors like mass transport or chemical reaction were analysed. The Mn content in the bath were varied and it was concluded that by increasing the former, dissolution of Mn into the bath was increased, so as a reduction of MnO in the slag. For carbon dissolution, it was used a experiment with a stationary bar, this one was added into the bath, after ten minutes probes were catched, by temperature 1600¦C, for the dissolution of MnO, one graphite crucible was employed, after 45 min the slag and alloy were analysed. After the experimental part, some curves were plotted against time, based on these graphics, and kinetic analysis was made.

Jan 1, 1999

By R. W. Pugh, D. G. Bellow

"This paper will describe how cultivator shanks are made in one company and how the manufacturing was studied with a view to increasing product consistency and reducing manufacturing cost. The product: which is used extensively in the agriculture industry, was analyzed to determine which geometric parameters optimized its design and whether there was justification for the great variety of styles and shapes that are available in the market. Finally, an extensive series of field trials were undertaken which showed that it is advantageous to the manufacturer to be better aware of the loads and forces that his product is subjected to by another industry.IntroductionStelco maintains a Research Group for its Western Region operations headquartered in Edmonton, Alberta. Because of the small staff, a location that is isolated with respect to its Burlington, Ontario centre and a diverse set of processes and products, a university relationship has developed which may be different from that which would be developed at a larger integrated Steel Works. This paper outlines the type of cooperative studies carried out by Stelco Inc. in Edmonton and the University of Alberta. .To meet the research needs covering a wide variety of steelmaking processes and steel products produced in Edmonton would require more staff and equipment than the sales volume in the West justifies. The gap is filled by cooperation with university personnel. This cooperation has provided these benefits to Stelco Inc.:• access to specialized test equipment and a trained staff to operate it; and• assistance from experts in the areas of product testing and problem solving.Moreover, the close proximity of the university to the plant allows frequent meetings and ensures that practical solutions are developed and implemented. A good example of the ongoing university I industry relationship developed is the joint work on improving cultivator shanks."

Jan 1, 1982

By P. Botane, A. Cailleau

"Compagnie Miniere Esperance operates a gold primary ore body. The ore is processed through crushing, grinding and gravity concentration generating tailings with remaining fine gold. Analyses of the tailings proved a residual gold grade sufficient for a chemical treatment.As lab tests proved the technical feasibility of a pre-concentration using flotation, an on-site pilot operation has been carried out to assess the continuous circuit performances, define the best configuration and obtain enough data for the industrial circuit sizing.Data collected during the pilot campaign have been used for calibrating a process simulator built with the USIM™ PAC software. The simulator validated the feasibility of upgrading the existing plant, including the reprocessing of tailings to obtain a good fine gold recovery in a small amount of concentrate. A preliminary capital cost has been achieved to assess the flotation workshop profitability.INTRODUCTIONCompagnie Miniere Esperance (CME), a mining company based in French Guyana, operates a gold primary ore body in open pit. The ore is processed through crushing, grinding and gravity separation in two stages: a top plant and a bottom plant. A “coarse” pond contains tailings of the top plant; this product feeds the bottom plant. Tailings of the bottom plant are stored in the “fine” pond.Analyses of the fine ponds proved a residual gold grade sufficient for a chemical treatment. However, direct cyanidation would require a too large installation, regarding the local conditions (accessibility, supplying and meteorological conditions).It has been then decided to test the feasibility of a pre-concentration using flotation. Lab tests have been carried out by SGS Lakefield (Canada) in March 2007, which proves the technical feasibility."

Jan 1, 2009

By J. A. Caceres

Mining planning and mineral processing are almost two unconnected areas. The mining area builds its economical models considering the plant like a constant parameter: a constant throughput, an average recovery and a unitary cost. On the other hand, the mineral processing area assumes a mine plan with grades, ore type, work index, estimating the performances in an independent way. Previous researches have evaluated the advantage for increasing throughput by increasing the liberation size, thus sacrificing recovery. These valuables approaches have left behind the work index factor, critical variable for Recovery-Throughput capacity estimation. This study describes a method combining mineral processing and mining planning. This method incorporates the grinding and flotation performances into the mining economic models optimizing simultaneously the Throughput- Wi(Work index)- Recovery relations with mining sequence, cut-off strategies, and reserve schedules. This method has been used at Andina Mine Chile, showing 18% net present value increasing with minimum investment associated.

May 1, 2003

By G. Stokreef, B. R. Davis, M. Kadiyski, Alvear Montenegro, H-P. Loock, V. Montenegro

An optical probe for burner monitoring in copper flash smelting, first developed at the University of Concepcion, is being industrially tested in a collaboration between Kingston Process Metallurgy, Aurubis AG, and Queen’s University. The sensor uses fibre-optics and optical emission spectroscopy to analyze the light emitted from combusting particles in the furnace reaction shaft. Information that can be extracted from the emission spectrum includes the temperature and brightness of the flame, as well as emission lines or bands from excited atomic and/or molecular species. Laboratory proof of concept testing of the sensor was first completed in a continuously fed drop tube reactor using O2/S stoichiometric ratios between 0.8–4.0. These O2/S stoichiometries capture the industrial operating condition, which is typically less than 1. The results from lab testing justified a plant trial of the optical probe, which was done in the Aurubis Hamburg flash furnace in September 2018. From this trial, approximately 31 hours of spectral data were collected and synchronized with furnace operating data. The results from both drop tower test work and the plant trial are discussed with implications for process monitoring in the commercial furnace. INTRODUCTION Flash furnace smelting is a continuous feed, batch tap, pyrometallurgical process. It is used to treat copper sulphide concentrates and small amounts of secondary materials, such as dust generated by the process. O2 enriched air and the concentrate blend are fed into the furnace reaction shaft through the concentrate burner. As the particles fall through the reaction shaft, they heat up and ignite, causing rapid, exothermic reactions that oxidize the iron sulphide, some copper sulphide and impurities in the feed. Reacted particles fall into the settler of the furnace, melt and separate into a matte and slag, while the SO2 enriched off-gas is carried out of the furnace for heat recovery and H2SO4 production. Operation of the furnace is achieved by adjusting a limited number of control variables. The main variables are the blast feed rate, blast oxygen enrichment, SiO2 flux feed rate and CH4 combustion rate (CH4 is used when the chemical energy of the concentrate is low) all measured relative to a set feed throughput. (Davenport & Partelpoeg, 1987; Davenport, King, Schlesinger & Biswas, 2002) The batch tapping nature of flash furnaces makes operation difficult because these control variables impact each other, and product quality can only be measured when matte and slag are tapped from the furnace. This means that operation of a furnace is based on feedback control from matte and slag assays. Because of the time-delay associated with understanding product quality, there is interest in using technology to monitor the combustion reactions that happen in the furnace reaction shaft.

Jan 1, 2019

By Martin Herrenknecht

Tunnel boring machine (TBM) development continues to take on not only larger diameters, but also more difficult ground conditions. Ground conditions consisting of unstable faces with water pressures up to 15 bar have required innovative design approaches. A systems approach has been required to produce tunneling machines that can safely excavate the tunnel in an efficient, cost-effective manner that stresses production and labor saving approaches. This article reviews the current design developments and present recent projects where these most recent principles have been applied. The world?s growing population and rapidly proceeding urbanization are boosting an enormous demand for new and high-capacity infrastructures to secure the mobility of goods and people. Densely populated areas face the challenge of providing efficient traffic infrastructure such as a modern public transport system. At the same time, the maintenance and modernization of supply and disposal structures for water, sewage, energy and communication are essential. Last but not least, are supra-regional transportation routes such as long distance water diversion schemes. All of these projects are as demanding and are characterized by a tight time schedule. In this context, the demand for efficient tunnels for traffic and utility lines is increasing, as new infrastructures often leads underground because of limited space above ground. Also, tunnels are the obvious choice to cross natural barriers like mountain ranges. To handle the complex and variable geological conditions and other constraints, such as low overburden, high water pressure or long tunnel drives while facing increasing demand of a quick completion of a project, mechanized tunneling sets standards regarding safety, profitability and environmental protection in traffic tunneling projects as well as in the trenchless construction of utility tunnels. Different machine types and working principles have been developed to master various geological and hydrogeological requirements. Continuous activity in research and development leads to constant improvement of the mechanized tunneling process.

Jan 1, 2008

By Joseph Daly

This is the detailed evaluation of the establishment and implementation of an ‘oil recycle plant’ located on site at Boggabri Mine NSW, (Australia); its production, its use and its value. Also discussed in detail is the quality of the raw material produced, and the process and initial application of this raw material generated as well as the analysis of such, as a component within bulk explosive as applied to the mining industry as compiled during analysis. Laboratory analysis prior to field testing is also discussed including independent external laboratory analysis as well as the environmental benefits and a business case for recycled oil in blasting. This paper includes technical details of the product including densities, velocity of detonation and other associated key performance indicators. The intention is to off-set the amount of Distillate (Diesel) utilised as a component of bulk explosives, with a raw recycled oil and thus reducing both the environmental carbon footprint as well as production costs with regard to introduced petrochemical production and utilisation; an oil that is an existing recourse of controlled waste not only difficult but expensive to otherwise dispose of, whilst keeping the entire process ‘on-site’. Though recycled oil in blasting is not an entirely original idea, the key feature of this paper is the ability to complete the entire process on-site.

Jan 1, 2014

By K. Häge

"Die Nachhaltigkeit der Braunkohlengewinnung in der öffentlichen Wahrnehmung wird nur weiter erfolgreich kommuniziert werden können, wenn durch konkretes Handeln glaubhaft gezeigt wird, dass die offenen Fragen fair und solide beantwortet werden. Dazu gehören insbesondere die neue innovative technische Lösung sowie das sensible Interessenmanagement. Die Braunkohlenindustrie hat gelernt, dass Offenheit und nicht zuletzt das beständige Bemühen um den Meinungsaustausch mit ihrem Umfeld wichtige Elemente sind. Der in Jahrzehnten erworbene Schatz an Glaubwürdig-keit ist eine Basis, auf der die Braunkohlenindustrie ihre Zukunft gestalten kann. Darüber hinaus sind politische Rahmenvorgaben erforderlich. Das öffentliche Interesse an einer sicheren und preiswerten Energieversorgung unter Einschluss der Braunkohle ist unverzichtbar. In diesem Kon-text kann dann die Braunkohle die an sie gerichteten Fragen der Ökonomie, der Ökologie und der Sozialverträglichkeit auch mit Hilfe von Indikatoren beantworten.ABSTRACTThe discussion of the sustainability of lignite mining can only be continued successfully if the indus-try acts in a practical manner and demonstrates trustworthiness by responding fairly and reliably to open questions. This includes new and innovative technical solutions as well as the sensitive management of interests. The lignite industry has learned that openness and the constant effort to exchange viewpoints within their environment are all essential elements. The credibility that has been gained over the decades is the foundation on which the lignite industry can build its future. Beyond that a framework of political guidelines is necessary. Public interest in a secure and inex-pensive energy supply that also includes lignite is indispensable. In this context, the lignite industry will then be able to answer the questions which are directed at them and concern the economy, ecology, and social tolerability also by indicators."

Jan 1, 2005