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By Kelsall D. F, Trahar W. J

The size by size batch flotation behaviour of copper activated sphalerite from synthetic mixtures with quartz was determined. In terms of recovery of sphalerite, the size fractions could be grouped into coarse, intermediate, and fine ranges. The behaviour of the coarse and fine ranges was significantly poorer than that of the intermediate range in both the extent and rate of flotation.Each size fraction had a fast and a slow floating component.The main effect of changing the copper sulphate addition was to alter the proportion of any size fraction which was fast floating. No correlation could be found, between the amount of copper on the spha:lerite andeither the flotation rate of the mineral or the amount of copper added to the system. It was found that fine particles did not appear to consume greatly disproportionate amounts of copper sulphate during conditioning. A modified conditioning procedure was found to lead to a higher rate of flotation and recovery of coarse sphalerite and to make poss1ble substantial savings of copper sulphate.

Jan 1, 1975

When asked to lecture at Bendigo on the geological factors that determine the depths of ore deposits, I hesitated for a little before agreeing to lecture on the theory of deep ores in the city world famous as the pioneer of deep gold mining. If there be one place, wherein the conditions of deep-seated ore deposits should be sufficiently well understood, it is the city where the 180 mine made its bold plunge to previously neglected depths; and where the record of that famous mine has been broken by the skill of the managers, and the pluck of the proprietors, of the New Chum Railway and Lazarus mines.In the face of such practical triumphs, theoretical discussion may seem a waste of time, especially since it is often dedared that the existence of such deep-seated ores was denied by geological theory. This assertion is, however, startling since the oldest and best supported geoiogical theory of ore deposits, has taught for more than a century tliat ores must descend far below the regions of practical mining. This charge against Victorian geologists is generally based on opinions attributed to the late Sir Fredrick McCoy. It has been repeatedly affirmed that he declared that gold cannot occur pelow a depth of 300 feet. But so far I have not been able to discover that McCoy ever made any such assertion or ever held such a view.

Jan 1, 1902

By Wenquan Zhang

Based on the mining and geological conditions of Wadong Mine, Longkou City, Shandong Province, China, a viscoelastic model with proper creep parameters was established. The 3-D ANSYS was used to simulate surface subsidence, analyze overburden subsidence characteristics, and propose the rational mining and pillar widths for mining in weak rocks and under special mining conditions, and provide the policy makers scientific data for decision making on mining activities.

Jan 1, 2006

Modelling and Optimisation of Direct Reduction of Iron Ore by Coal in a Rotary Kiln

Sep 13, 2010

By Fidelis T. Suorineni

Rockbursts are a major hazard in deep hard rock underground mining and tunneling. To date a significant number of rockbursts still defy conventional explanations. A review of rockburst case histories in the literature has shown that pillars and tabular excavations under shear loading are prone to rockbursting in situations where they are least expected under conventional knowledge of rockburst causes. Despite the evidence of the effects of shear loading on underground infrastructure, and the frequency of their occurrence, little is known about how this loading mechanism causes such large magnitude events and extensive damage. In this paper analytical and numerical modeling are used to understand the behaviour of pillars and tabular excavations under shear loading. The numerical modelling results show that pillars under shear loading are less confined than their equivalents in loaded in pure compression in the same geologic environment, and are therefore more brittle and weak. For tabular excavations under shear loading, the behaviour depends on whether such excavations are continuous, co-planar or offset with rock bridges. Analytical results based on slit theory show releasable potential energy in tabular excavations increases nonlinearly with excavation half-span. The study results are important for the safe and economic extraction of orebodies under shear loading.

May 1, 2011

By T. McKeon

Gravity separators are commonly used in multistage cleaning and scavenging circuits to improve the quality and/or recovery of the final concentrate. Unfortunately, studies suggest that many industrial plants are poorly designed in terms of equipment layout. This shortcoming can often be attributed to a failure by engineers to make use of fundamental process engineering tools for circuit design. One of the most important of these is linear circuit analysis. This powerful tool makes it possible to mathematically compare the relative efficiencies of circuit configurations in advance of experimental testing. This article provides a basic review of the linear circuit analysis concept and discusses some of the key insights it provides for the layout of multistage circuits. An industrial case study is provided to show the tremendous impact that this process engineering tool can have on the design of multistage spiral circuits in a heavy mineral wet plant.

Jan 1, 2005

By J. E. Bernick, J. Davies

This paper describes the design and construction of a 22.86 m (75 ft) long jacked tunnel, which was successfully installed, despite difficult mixed face conditions at Metro-North’s Westport Station, in Connecticut in the fall of 2003. The tunnel utilized what is believed to be, the first application of a steel grillage system within the United States. This grillage was installed before the jacking started and allowed the tunnel to be jacked under four live railway tracks, which included the Acela high speed line, without affecting train operations. The clearance between the top of the tunnel and the rails was only 0.9 m (3 ft).

Jan 1, 2005

By Srinivasulu Tadisetty

The productivity and safety of Indian longwall operations are insignificant because of complex geomechanical conditions. Therefore, the continuous monitoring and forecasting of abnormalities is imperative. Authors developed an innovative real time system and implemented in one of the Indian longwall mines. The real time system was successfully acquired data from underground chock shields and classified the behaviour in real time as per the standard norms. Furthermore, it forecasted the abnormal behaviour of chock shields promptly. The management was implemented appropriate precautionary measures based on real time forecast. Subsequently, the longwall operations were successfully completed with enhanced productivity and safety. This paper discuss the impact of the innovative system on productivity of experimental longwall mine.

Jan 1, 2006

By Lewis Martin

Whereas many researchers and mine engineers have conducted tests using different types of grout, grout ratios, and physical modifications of the cable to determine cable bolt load characteristics, few studies have been conducted on cables fitted with internal instruments. Those studies that have been done have concentrated on cable behavior averaged over significant cable lengths. Researchers at the Spokane Research Laboratory (SRL) of the National Institute for Occupational Safety and Health in Spokane, WA, are investigating the physical properties of cable bolts by replacing the conventional king wire with a modified king wire on which strain gauges have been installed . This paper documents test results on these modified cable bolts. Three tests were conducted at SRL on 1.83-m-long cables grouted into two 0.91-m-long pull-tube assemblies. Load along the cable was monitored with 20 strain gauges installed along the length of the cable. The instrumented cable bolt provided reproducible point measurements of cable load as opposed to load measurements averaged over significant cable lengths. Such point measurements can assist in interpreting the influence of cable confinement, grout quality, rock mass stiffness, and other factors. The instrumented cable bolt is a practical field and research tool because it can predict point loading along the cable and thereby allow interpolation of maximum possible loads on a cable.

May 1, 2002

By Gary B. Petersen

The author has developed a seven-step process called the Applied Rock Mechanics (ARM) Protocol that the author has used to solve numerous roof stability problems in mines throughout North America since 1975. It is a practical evaluation process using trained observation, innovative data collection instrumentation, video borehole cameras, analytical processes, and controlled testing methods that have become highly effective in solving ground control problems in every type of underground mine. This paper will describe each of the steps of the protocol and how the rock mechanics engineer applies them to resolve a typical ground control problem.

Jan 1, 2012

The excavation of ramps and tunnels often requires high-speed development with (or without) the use of high-energy mining equipment such as loaders, dump trucks, TBMs and roadheaders. This high-speed development creates a challenge in terms of providing a safe and productive working environment. For example, heat from continuously exposed surrounding rock, heat from broken rock, heat generated by mining equipment, potential in flows of hot ground water, pollution from associated diesel equipment and the distance of the advancing face from fresh through-ventilation all have to be taken into account when designing ventilation systems for high-speed ramp and tunnel developments. This paper discusses methods of achieving acceptable environments at the face and along the length of the tunnel. The methodology has been successfully implemented in the development of long (up to 20 km) TBM drives in the Lesotho Highlands Project and in mining projects in hot rock using drill and blast methods as well as mechanized methods using continuous miners and roadheaders. The determination of heat loads includes calculation of the heat flow within the surrounding rock, evaluation of the operating cycle of the equipment and the contribution to the overall heat load of the broken rock as it travels out of the tunnel. The determination of heat loads from surrounding rock in new tunnels required a modification of the algorithms generally used for established excavations. The paper also examines the use of, for example, mobile duct and fan systems to ensure that fresh air is delivered to the specific areas where workers are located.

Jan 1, 2000

By S. Dessureault

Computer Integrated Mining (CIMG) is a process of using computer networks to transform islands of enabling technologies into a highly interconnected mining system. CIMG involves the integration of advanced technologies at various levels in the mine business to achieve higher flexibility, better quality of processes and control, and improved profitability. Justifying the benefits of CIMG are difficult as many of the advantages are derived from improved flexibility, quality, and control. Justification is based on the evaluation of the benefits to be gained, compared to the required capital investment. Management tools used in mining are currently inadequate in assessing the value of advanced technology whose benefits are primarily qualitative. A key aspect of successful implementation is management acceptance, which has to be won through the capability to justify the technology?s financial costs and the true value of all of its benefits. The manufacturing industry faced similar justification difficulties when adopting advanced technology in factories. A significant amount of funding and research was invested in developing management strategies and approaches to justification. Many of the problems that faced the transformation of the manufacturing industry in the late Eighties and early Nineties are now facing mining. The solutions derived for manufacturing may help mining in its transition to an increased reliance on integration technology. Reviewing the industrial history of computer integrated manufacturing identifies several tools and strategic frameworks that can be adapted for mining. Keywords: Computer integrated mining, justification techniques, CIM, information technology.

Jan 1, 2004

As we look back through the Proceedings of our Institute, we find few papers dealing directly with education and recruitment. Apart from papers prepared in the earlier decades of this century, there was little written discussion on the subject until the 1950s, and mostly this was by the professionals, the professors and lecturers who staff the various mining schools of Australia and New Zealand.I use the term "mining school" in its fullest and widest meaning, to cover all aspects from ore to metal, and not in the narrow meaning that the word might imply. At the same time, in restricting the parameters of this address to "ore to metal" I recognize that I am excluding the very important fields of physical metallurgy and materials science; this I do because there is a limit to the quantum of any paper, and in fact these subjects are more closely allied to the use rather than the production of metals.However, the lack of education papers does not mean that education has been regarded lightly by The Institute. Sir Maurice Mawby in his presidential address in 1968, reminded us of the original objectives of The Institute, one 'of which was, "To promote the arts and sciences connected with the economical production of the useful minerals and metals ...". Our present Royal Charter is more specific when it says that one of the objects of The Institute is, ". . . to encourage the study of engineering with special reference to mining and metallurgy ...". If we recognize that in itself membership of our Institute is one means of continuing our education, it is true that education has been a concern of The Institute since it was first founded.Occasionally in recent years, an intrepid president has ventured to tell the academics what the industry needs, and he generally does this in a "no-question" situation! However it is encouraging that those entrusted with mineral education have always accepted this; they keep coming back for more and ask us to tell them what we want, and they will provide it.In 1948 a considerable dialogue on education was initiated when a standing committee was established by the Council of The Institute. In the period 1949 to 1951, three papers were prepared under the chair...

Jan 1, 1974

The banded iron formations "jasper bars," jaspilites, banded hematite quartzites or banded ironstones, etc., as they have. variously been termed in Western Australia, constitute one of the most striking features of the Pre-Cambrian in this State. They occur in at least two distinct divisions of the Pre-Cambrian, viz., in horizons interbedded with quartzites, shales and thin bedded dolomite in the N~llagine (Proterozoic) Series; and amongst the Older Pre-Cambrian rocks, associated with the metamorphosed sediments of the Jimperding-Chittering Series, the Yilgarn Whitestone Series and the Mosquito Creek Series, and interbedded with metamorphosed basic lavas, tuffs and sediments of the Older prenstone or Kalgoorlie Series.In the Hamersley Ranges in the north-west of Western Australia banded ferroginous cherts are well developed amongst the horizontal sediments of Nullagine Age. These iron formations have recently sprung into prominence as they have been found to form the host rocks for important deposits of· blue asbestos. They are closely comparable with the unique crocidolite-bearing banded ironstones of the Cape Province, South Africa, and have been described elsewhere in some detail by the writer. (1) t .The banded iron formations with which it is intended to deal principally in the following pages, form most abundantly in the Central and Eastern Goldfields of Western Australia where they form portions of the Older Greenstone or Kalgoorlie Series of auriferous rocks. In these regions their chemical inertness and physical hardness provide considerable resistance to the agents of erosion and consequently they frequently stand out in strong topographic relief in otherwise monotonously flat or gently rolling country. These banded-iron formations have proved of considerable direct economic importance in the goldfields and in other portions of the State because of thei!! associations with 'gold, iron -and to' a lesser extent, manganese; whilst indirectly because of their peculiar nature, form and topographic prominence, etc, they have been of tremendous assistance to the field geologist both in the practical application of methods of geological mapping and in the' elucidation of geological structures. Finally, they have recently acquired a new importance in the specialised search for ore-bearing lodes or for structural information over areas of soil-covered country, as their form and composition make them ideal subjects for the use of either electrical or m!1-gnetic methods of geophysical prospecting.

Jan 1, 1941

By M. R. Madhav

The ultimate pullout capacity of single batter piles has been presented in literature in three contradictory trends. These trends are: the pullout capacity of a single batter pile increases, remain almost constant, or decrease with increasing the inclination angle of the pile. The present paper presents a theoretical study which explained these trends in terms of existing initial stress condition and the earth pressure coefficient at rest. The paper also presents a form of guideline for predicting the pullout capacity of inclined piles based on simple field and/or laboratory tests.

Jan 1, 2010

This study explores two evolving 3D surveying technologies, photogrammetry and laser scanning, and applies them to deformation monitoring of rock faces and mine highwalls. A quantitative analysis focused on 3D coordinate determination is performed. Furthermore, a qualitative assessment directed at the practicality and viability of each system operating near a rock face or in a mining operation is undertaken to reveal one systemÆs deficiencies over the other. Two photogrammetric and four laser scanning surveys aimed at optimising accuracy and precision within a short period of data acquisition are conducted on the rock face at Organ Pipes National Park, Keilor, Victoria. The accuracy and repeatability of each survey is determined using a combination of iWitness photogrammetric, and Cyclone laser scanning software. The 3D coordinates of targets placed on the rock face are determined by triangulation and resection principles within a bundle adjustment. The coordinates determined by each system are then compared in a 3D transformation. Controlled deformation conditions are established to determine the precision to which each system can detect movement in the rock face. An object of known dimensions is placed on the rock face to simulate deformation. The relative orientation of images taken for the pre- and post-deformation photogrammetric surveys provide an overall 3D point accuracy of 1.255 mm and 1.804 mm respectively. A 3D transformation shows discrepancies of less than ¦22 mm (RMS) between the geometry of the photogrammetric and laser scanning models. Both systems are able to detect the simulated deformation to a precision of 50 mm. This work also identifies how to obtain millimetre accuracy for 3D coordinate determination of rock faces, thereby providing a quality data set for surveyors, geotechnical engineers and mine geologists. Photogrammetry is shown to be a mobile, time and cost-effective technique that is more amenable to mining operations than terrestrial laser scanning. However, both systems demonstrate that they are capable of detecting movements that may lead to failures in the rock face, and possibly endangering human life. The implications are significant for surveyors, geotechnical engineers and mine geologists working in mining operations where enhanced safety conditions, increased productivity and lower operational costs are important considerations.

Jan 1, 2009

By Lynch A. J

Comminution within rod mills has been investigated by use of a matrix analysis of breakage processes. A parameter, the number of breakage stages, has been introduced and comminution within all rod mills has been expressed in terms of the number of grinding stages and a function which describes the feed rate, mill diameter, and mill speed. The effect of variation in feed rate, feed sizing analysis and mill speed on the number of breakage stages is discussed, but no general relation is proposed because more study is needed.INTRODUCTIONRod mills are normally used as the first unit of multi-unit systems for the grinding of metalliferous ores and the cost of operating rod mills may be considerable. For both economic and metallurgical reasons, it is therefore necessary that the mills should be operated efficiently and that a knowledge of the mechanism of the size reduction process within rod mills should be as complete as possible. While a qualitative assessment of the process may be of some value, a quantitative assessment gained by describing the process in mathematical terms can be of much greater use because it may also be used for design and control purposes.In this paper, an empirical mathematical model is postulated to describe the size reduction process within rod mills and it is used to analyse the effects of variations in both rates and size distributions of the feed to the mills.GRINDING CHARACTERISTICS OF ROD MILLSMyers (1953) discussed the grinding characteristics of rod mills and suggested that a pronounced screening effect, resulting in the preferential grinding of the coarser particles, occurs within the mills. This is illustrated in...

Jan 1, 1964

By Terry G. Montgomery, Eric S. Weiss, John E. Going, Kenneth L. Cashdollar

The Pittsburgh Research Laboratory (PRL) of the National Institute for Occupational Safety and Health (NIOSH) and the Mine Safety and Health Administration (MSHA) conducted joint research on dust explosions by studying post-explosion dust samples. The samples were collected after full-scale explosions at the PRL Lake Lynn Experimental Mine (LLEM), and after laboratory explosions in the PRL 20-L chamber and the Fike I m3 chamber. The dusts studied included both high- and low-volatile bituminous coals. Low temperature ashing for 24 h at 515 °C was used to measure the incombustible content of the dust before and after the explosions. The data showed that the post-explosion incombustible content was always as high as, or higher than the initial incombustible content. The MSHA alcohol coking test was used to determine the amount of coked dust in the post-explosion samples. The results showed that almost all coal dust that was suspended within the explosion flame produced significant amounts of coke. Measurements of floor dust concentrations after LLEM explosions were compared with the initial dust loadings to determine the transport distance of dust during an explosion. All these data will be useful in future forensic investigations of accidental dust explosions in coal mines, or elsewhere.

By S. E. Olsen, K. Tang

The complex heterogeneous equilibria associated with the production of manganese ferroalloys have been simulated by employing recently developed thermochemical databases. The non-ideal Mn-Fe-Si-C alloy and the MnO-SiO2-Al2O3-CaO-MgO-FeO slag system have been modelled separately by the compound energy and cellular model. A large number of experimental thermodynamic and phase-equilibrium data were used to evaluate the model parameters for the liquid and solid Mn-Fe-Si-C phases. In addition to the liquid metal phase, solid mixture phases occurring in the Mn-Fe-Si-C system have also been studied. Over 500 measured equilibrium data have been utilised to verify and calibrate the model calculations. The paper will present typical simulation results, from activities of components to multicomponent heterogeneous equilibria. Good agreements can be obtained for many important technological parameters such as carbon solubility, phase relations and equilibrium diagrams, element distribution as function of temperature and slag composition etc. Application of the present models to the silicomanganese production will be demonstrated in this paper.

Jan 1, 2004

By K. Aoki, Y. Mito, S. Shirasagi

The authors developed the TBM Excavation Control System (the TBM Navigator), in order to realize the advanced observational construction. During the excavation using this system, the rock strength value is immediately calculated from the TBM driving data as an index of rock properties, and the drill energy coefficient is also calculated from the drill logging data that is carried out using the probe hole ahead of the tunnel face. In this study, a new, geostatistical simulation-based method is proposed for the automatic prediction of the rock properties ahead of the tunnel face with good precision, using both the drill logging data and the TBM driving data. The applicability of this method is validated through the prediction at the actual tunnel excavation that passes through the faults. Les auteurs ont mis au point un Système de Contrôle de forage avec la machine à pleine section (Navigateur de la machine à pleine section), en vue de réaliser un système de surveillance plus efficace. Avec ce système, la résistance de la roche est immédiatement calculée, au cours du forage, à partir des données de conduite de la machine, comme indice des propriétés de la roche, et le coefficient d'énergie de la foreuse est également calculé à partir des données de log de forage collectées dans un trou de sonde foré dans le front de taille. Dans cette étude, on propose une nouvelle méthode basée sur la simulation géostatistique qui permet de prévoir d’une manière automatique, des propriétés de roches se trouvant derrière le front de taille avec une précision satisfaisante, à l’aide des données de log de forage et celles de conduite de la machine à pleine section. Cette méthode s’est avérée suffisamment précise au cours du forage d’un tunnel réel qui traversait une zone de failles. Die Autoren entwickelten das TBM Ausschachtungssteuerungssystem (den TBM Navigator), um noch besser überwachte Bauarbeiten zu ermöglichen. Unter Einsatz dieses Systems wird die Gesteinsfestigkeit während der Ausschachtungsarbeiten unmittelbar aus den TBM Antriebsdaten als ein Index für die Gesteinseigenschaften berechnet. Gleichzeitig wird auch der Bohrenergiekoeffizient aus den Bohrlogdaten berechnet, die an Hand der Probebohrung am Stirnende des Tunnels erhalten wurden. In der vorliegenden Studie wurde ein neuartiges, auf geostatistischen Methoden basierendes Verfahren für die automatische und angemessen genaue Vorhersage der Gesteinseigenschaften am Stirnende des Tunnels vorgeschlagen, für das sowohl die Bohrlogdaten als auch die TBM Antriebsdaten verwendet werden. Die Anwendbarkeit dieser Methode wird durch die Vorhersage bei einer tatsächlichen, durch Verwerfungen verlaufenden Tunnelausschachtung bewiesen.

Jan 1, 2003