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By R. Hart

In this paper, problems that have been experienced with the rockpass system at Kloof Mine No. 3 Shaft are described. Actions that have been taken to overcome the problems are also described. These include the use of slugshots to remove hang-ups, the abandonment and waste filling of passes, and design criteria adopted for an alternative pass system.

Jan 1, 2006

By Arturo Ressi di Cervia

From the times when men in lacustrine environments drove wooden piles into the mud to elevate their dwellings, until the beginning of the twentieth century builders reacted to the conditions found in the location of their proposed structures by attempting to distribute their loads in ways that could be supported by the foundation's soils; or, if those were unsuitable, by moving the structure, whenever possible. While many major structures were built on stable ground (the pyramids were founded on rock), others were built on [ ]

Jan 1, 2000

Knowledge of true block grades is obtained from a mathematical model of an orebody, simulated with sample grades normally distributed and spatially correlated according io a spherical semi-variogram model.The superiority of kriging to the polygonal method of estimation is demonstrated on this modelled deposit by comparing the true values with the kriged and polygonal estimates obtained from sampling the deposit. Finally, selection of blocks of the deposit on the basis of the estimated values, shows that if kriging is used, what is predicted is largely mined, whilst if the polygonal method is used large biases can occur depending on the position of the cut-off grade.

Jan 1, 1978

By Zhan Jing

Keywords: thermodynamic, Ni-Co alloy powders, composition, fibrous The mathematics model of Ni(II)-Co(II)-C2O42?-NH3?H2O-H2O of thermodynamic equilibrium system has been developed theoretically according to the law of conservation of mass and the law of simultaneous equilibrium, and the logarithm concentration-pH (log[Me2+]T-pH) diagrams of this system have been made. The effect of ligand and pH value was studied. Two issues in coprecipitation route to synthesize fibrous nickel-cobalt alloy precursor powder, com-position and morphology which are a first priority, are addressed based on thermodynamic analysis and experiments. The results show that suitable pH value range of coprecipitation of nickel ions and cobalt ions in theory can be obtained to maintain fibrous, excellent compositonal homogeneity and stoichiometry in coprecipitation products. Experimental demonstration is also carried out.

Jan 1, 2005

By D Mnller, J L. Mauk

The Oblaga Cu-Au skarn deposit and porphyry prospect is located in the south-eastern edge of the Gobi Desert in western Inner Mongolia. The deposit occurs within metamorphosed middle Paleozoic volcanic, plutonic and sedimentary rocks.   Ivanhoe geologists recognise eight main rock types in the area. Calcareous sediments include conglomerate, interlayered siltstone-sandstone, and limestone. Covering the calcareous sediments is a slab of thrusted biotite granite, and above it is rhyodacitic lithic tuff which, in places, is overlain by alluvial sediments. Various plutonic rocks and related intrusion breccias have intruded these units. Monzodiorite, quartz-monzonite and monzonite tend to form thin, high-angle intrusions and the youngest andesitic intrusions are generally wider and subhorizontal.   The Oblaga Cu-Au skarn, which occurs in the calcareous sediments, shows typical prograde and retrograde mineralogy. Petrographic studies show that prograde skarn minerals have been overprinted by retrograde skarn minerals, and original host rock minerals have been texturally obliterated and completely replaced. The mineralogy of the Oblaga skarn deposit is very similar to other Cu-Au skarn deposits worldwide.   Sericitic and minor chloritic alteration occurs throughout the study area and may relate to porphyry-style mineralisation. Generally, this alteration is not intense and most rocks have retained their original texture. Geochemical analyses suggest that K-metasomatism is not widespread at Oblaga. XRD analyses suggest an upward and outward transition from sericitic to chloritic alteration.   Comparisons between Oblaga and other porphyry Cu-Au deposits worldwide show that Oblaga has very similar characteristics to deposits that have undergone sericitic alteration. However, Oblaga is special because it also has relatively intense chloritic alteration, which is uncommon in other porphyry Cu deposits described in the literature.

Jan 1, 2005

By M. A. H. Shuva, M. A. Rhamdhani, G. A. Brooks, S. H. Masood, M. A. Reuter

Ferrous-calcium-silicate (FCS) based slag has been used in the copper industry over the last two decades. The FCS slag has also been used in a secondary copper processing such as in black copper smelting which has different operation conditions compared to that of typical primary copper processing. In the process, a variety of copper bearing scraps from sources such as industrial waste, consumer waste and electronic waste (e-waste) are used. The valuable metals in these sec- ondary resources are distributed in different phases during the process. Understanding the behaviour of the valuable elements at the relevant conditions is vital for optimizing the process and to maximize the recovery of the elements. In this study, we investigated the structure of Ge-containing FCS-based slag at different conditions (oxygen partial pressure and temperature) using Fourier-Transform Infrared (FTIR) spectroscopy to explore the effect of the polymerization on the behaviour of the valuable element Ge in the slag. It was found that experimental parameters significantly in fluence the slag structure, and therefore, the partitioning of Ge in the slag. A correlation between the distribution ratio of Ge and the slag structure has developed in the current study.

Mar 1, 2018

By R. V. Ramani

One area of study in the Coal Mine Injury Analysis project was to illustrate and enhance the ability of mine safety management personnel to apply analytical techniques to injury experience data and to justify requests for funds for safety enhancement actions on a cost/benefit and other quantitative basis. Four volumes of this final project report detail (1) the objective and scope of the mine safety management research, (2) the results of literature review, and case studies, and (3) models developed for mine safety management. The four volumes are titled as Volume III: Mine Safety Management, Volume IV: Analytical Techniques for Mine Safety Management; Volume V: Mine Safety Management Case Studies and Volume IX: Training Cost Model. In this volume, the following material is presented: (i) review of related literature, (ii) mathematical models to perform quantitative analyses of accident/ injury experience data using the tools and techniques of risk analysis, time series analysis, and the Markov process, and (iii) descriptions of the HDBSEL and ACIM programs which are used to perform accident/injury experience analyses and cost analyses, respectively.

Jan 1, 1993

By Reginald N. Boryor, Steven D. Woods

1.0 Introduction ?Low grade, high tonnage, open pit gold mine. ?Gold bearing Tarkwaian conglomerates. ?Reverse Circulation percussion drilling (25m X 25m grid). ?Composite 1m intervals, logged and split in the field to provide±2Kg samples. ?Samples used to build grade control block models using SURPAC. ?Approximately 100,000-130,000 meters drilled per year. ?RC samples are assayed using Rapid Cyanide Leach (RCL). ?Check assays are done using Fire Assay

Jan 1, 2005

By G. Lyman

The cross-belt sampler is a device that is very widely used even though it has not been ratified by the Standards associations. This paper is concerned with the bias testing of two cross-belt sampler designs against stopped belt samples and a cross-stream cutter at the belt end. The bias analysis is carried out using size distribution as the analyte and conventional t-testing and the Hotelling T squared test, which are compared for their effectiveness. The paper considers the issue of detectable bias and the statistical planning of bias tests.

Jan 1, 2010

By K. G. Thorne, D. R. Lentz, A. F. Park

"The Main zone of the Clarence Stream gold deposit is hosted by a shear zone adjacent to the Saint George batholith in southwestern New Brunswick. The mineralization history relates to progressive deformation in the shear zone and the intrusion of the Magaguadavic granodiorite.Of three phases of deformation that have affected the area (D1-D3), D1 is not observed in the Clarence Stream shear zone. Two suites of igneous rocks intrude the shear zone: post-D2, pre-D3 gabbro; and granitic dikes, which crosscut the gabbros. Granitic dikes show a diverse range of relationships to D3 features, from pre-syn-D3 mylonitic fabrics in transposed and highly deformed enclaves, to nondeformed and entirely discordant dikes (post-D3).A variety of veins occur within this shear zone. Zoisite-bearing and later, crosscutting epidote-bearing veins are preserved as relics in quartz-mylonites, and predate quartz veins that host gold mineralization. The epidote-bearing veins are associated with pseudotachylitic cataclasite dikes, consistent with transient brittle failure during ductile deformation.Deformation relates to right-lateral strike-slip motion across the shear zone, and subhorizontal and near-vertical stretching lineations imply transpression. A late (late- or post-D3) dip-slip phase of motion is also apparent, and cooling followed a metamorphic peak early in D2-D3 history. Deformation of the shear zone, and more localized transient brittle failure, provided the permeability for fluid movement and vein emplacement. This scenario is similar to the findings of other studies, in which geochemical, tracer isotopic, and age-dating (U/Pb, 40Ar/39Ar) results suggest that the adjacent Magaguadavic granodiorite provided heat and metals. La zone principale (Main zone) du gisement d’or de Clarence Stream est encaissée par une zone de cisaillement qui longe le batholite de Saint George dans le sud-ouest du Nouveau Brunswick. L’historique de la mise en place de la minéralisation accorde un rôle important à la déformation progressive dans la zone de cisaillement et à la mise en place de la granodiorite de Magaguadavic.Des trois phases de déformation à avoir affecté la région (D1-D3), les effets de D1 ne sont pas observés dans la zone de cisaillement de Clarence Stream. Deux suites de roches ignées se sont mises en place dans cette zone de cisaillement : un gabbro post D2, pré-D3 et des dykes granitiques qui recoupent le gabbro. Les dykes granitiques montrent une grande diversité de relations avec les structures D3, allant de précoces à synchrones aux fabriques mylonitiques D3 dans des enclaves transportées et fortement déformées à des dykes complètement discordants et non déformés (post-D3).On note diverses veines dans cette zone de cisaillement. Des veines contenant de la zoisite ainsi que des veines d’épidote sécantes plus tardives, lesquelles sont préservées comme reliquats dans les mylonites à quartz et sont plus vieilles que les veines de quartz contenant la minéralisation aurifère. Les veines d’épidote sont associées à des dykes de catacalasite à texture de pseudotachylite, compatibles avec une rupture cassante épisodique durant la déformation ductile.La déformation résulte d’un mouvement décrochant dextre le long de la zone de cisaillement et les linéations d’étirement subhorizontales et quasi-verticales impliquent de la transpression. Une phase tardive (tardi- ou post-D3) de mouvement selon le pendage est aussi apparente, et le refroidissement succède à un pic métamorphique tôt dans l’histoire D2-D3. La déformation de la zone de cisaillement et la rupture cassante épisodique ont fourni la perméabilité nécessaire au mouvement des fluides et à la mise en place des veines. Ce scénario est similaire à celui proposé par d’autres études, dans lesquelles les résultats de géochimie, de traceurs isotopiques et de géochronologie (U/Pb, 40Ar/39Ar) suggèrent que la granodiorite de Magaguadavic avoisinante a fourni la chaleur et les métaux."

Jan 1, 2008

By Z. T. Bieniawski

Geomechanics signifies the science and engineering of soil and rock materials and of rock masses. It is a field of professional practice and research that draws heavily on the elements of soil and rock mechanics. Geomechanics contributes to a number of disciplines: mining engineering, civil engineering, geological engineering, petroleum and natural gas engineering, and engineering geology (including the elements of geohydrology and geophysics). These disciplines are involved in the design and construction of such projects as mines, tunnels, foundations for structures, excavated rock slopes, dams, shafts, boreholes, oil reservoir wells, underground storage facilities for oil and gas, and hazardous waste repositories. Geomechanics allows us to improve both our environment and our quality of life. In the context of this Handbook, the scope of geomechanics is discussed mainly from the point of view of applications to mining engineering. However, the coverage of the subject mate¬rial is so comprehensive that it is relevant to other disciplines as well. Section 10 covers the field of geomechanics in a structured fashion, beginning with the fundamental principles and leading into practical applications in mining engineering. Throughout the treatment of the subject, knowledge of geologic conditions is assumed since this is discussed in other sections of the Handbook. An important feature of this section is a series of practical examples illustrating the various aspects of geomechanics. Since geomechanics is concerned with both soil and rock mechanics, Chapter 10.1 introduces the fundamentals of soil

Jan 1, 2008

By P Duplancic and C R Lilley, R Hudson, D Beck

For deep block and panel caving mines, undercut or extraction level instability can have as much impact on overall recovery as underbreak or the premature ingress of waste. If the area of the mine affected by excessive convergence is small, recovery is usually possible. However, there are several examples of entire blocks that were abandoned prematurely due to footprint collapse. Clearly, such global instability has a major impact on recovery and must be avoided – this is one of the essential tasks for the design team.The design problem is complex. The planning engineer must ensure that the footprint has sufficient capacity to withstand the maturing loads in the cave, accounting for the effects of stress path, geological structures and the rock mass conditions. These are often uncertain and only sometimes quantified.The demand on the footprint will also be influenced by decisions and actions taken during production, especially related to draw, which can worsen a developing problem. Perhaps most importantly, the design decisions that favour stability and lead to lower deformation also negatively impact on idealised cave flow. Many engineers aim to minimise the size of extraction level pillars, to improve theoretical future resource recovery but in fact this can reduce recovery if widespread deformation ensues due to the undersized pillars.In 2014, PT Freeport Indonesia undertook detailed numerical analysis to quantify the effects of variability in rock mass conditions and geological structure on overall footprint performance. The analysis accounted for a range of stress paths and maturing cave loading scenarios sourced from a calibrated whole-of-cave deformation-flow model. The intent was to replicate some of the diversity and distribution of pillar deformation outcomes that may be seen in practice at Freeport.The discontinuum finite element analysis was able to replicate damage localisation around persistent structures, a realistic distribution of drive deformation and show how small areas of instability can evolve into major problems if poorly managed. The limits of pillar size and ground support as solutions to a number of different instability problems was also investigated, showing that pillar size alone was not a sufficient remedy for all adverse circumstances.In this paper, we describe the workflow for numerical analysis of footprint deformation. We discuss the compromises and considerations for balancing the sometimes competing needs for efficient extraction levels pillars, ground support and prudent draw strategy.CITATION:Beck, D, Hudson, R, Wilson, A D, Duplancic, P and Lilley, C R, 2016. An investigation of factors affecting the long-term reliability of extraction level pillars in deep block and panel caves, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 295–304 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

Comminution is a vital part of minerals extraction, and therefore of the South African economy. The high cost and throughput-limiting nature of comminution forms a strong motivation for research directed at improving the efficiency of the process. Building on a ten year background of fundamental charge motion research, a new formal UCT flotation and communication group has been formed. The group is also moving strongly into the field of milling circuit modelling and simulation, based on close links formed with the Julius Kruttschnitt Mineral Research Centre (JKMRC) of Australia, and an international collaborative research programme.

Jan 1, 1998

By Eldon C. Pattee

Reconnaisance samples of reported beryllium occurrences in Idaho, Washington, Montana, and Oregon were chemically and spectroscopically tested in a mobile laboratory. The two predominant types of occurrences were green beryl associated with Cretaceous intrusions and disseminated aquamarine associated with Tertiary intrusions. Although the beryllium content of known deposits in the Northwest is too low for economic development at present, total submarginal-grade beryllium resources in pegmatites are estimated to be 570,000 to 1,870,000 tons containing 0.024 to 0.167 BeO. A potential source of 500,000 to 700,000 tons of beryllium-bearing tactite in Idaho and Montana averages 0.033 to 0.080 percent BeO.

Jan 1, 1968

By Eder Salazar

Como parte del desarrollo de sus operaciones de mina de cobre subterránea, la Sociedad Minera El Brocal S.A., desarrolló el método de minado tajeo por subniveles con pilares recorridas con el fin de incrementar su producción actual. En ese sentido, el presente texto señala la implementación de un método de minado conforme a las características geomecánicas del macizo rocoso del yacimiento.

Sep 12, 2011

By D Wyatt, J Domenico, W Kow

Over the past few years developments in heavy minerals processing have concentrated on the mineral separation portion of the business. The best example of this would include new developments in rare-earth magnetic separators and associated flowsheet modifications. Except for some minor modifications in spirals, the æwetÆ side of the separation business has lagged behind the ædryÆ side. Basic concentrator design has not changed in 20 years. Recent pilot trials by Outokumpu Technology have shown the benefits of a new gravity flowsheet that combines density separation and spiral concentration on a variety of heavy mineral deposits. This concept is already well utilised within the iron ore industry. The synergistic combination of these two technologies allows smaller, simpler, and controllable gravity concentrators to be built while providing equivalent or better grade and recoveries of valuable heavy mineral. This is contrasted to the all spiral flowsheet characterised by the diminishing returns of multiple stages of spirals and associated recirculating loads. Examples of the flowsheets and associated benefits will be presented from a variety of cases.

Jan 1, 2001

By Mark K. Larson

Calibration of LaModel for deep coal mines begins with adjustment of overburden stiffness for load transfer distance. This calibration determines whether mining induced stresses are concentrated in the immediate abutment of the gob, or spread over a wider area. In the absence of site information, an empirically-based estimate is often used. Where data is available, a recommended calibration procedure can be followed, as is done in this case study at a deep western longwall mine, with minor modifications and extensions. In this case, data sources included borehole pressure cells, flatjacks installed in series with support Cans, and observed changes in ground conditions. Calibration was based on the first detection of mining-induced stress from the advancing longwall. Detection was found to depend on the type and sensitivity of measurement. Borehole pressure cell data with a 20-psi-increase detection threshold were chosen as the standard, in accord with data used in deriving empirical relationships. Application of this standard produced a load transfer distance estimate roughly four times the empirical relationship developed by Peng and Chiang (1984). This is a significant deviation with important implications for panel design at this site. Data from flatjacks, ground condition observations, and borehole pressure cells with higher threshold values, were tightly clustered and show load transfer distances from two to four times empirical guidance. Ratios between various measurements can be used to adjust measurements to the standard (although they may depend on mine geology). Once established, ratios can be used to adjust estimates, say from support flatjacks or ground observations, to the standard, where borehole pressure cell data is not available.`

Jan 1, 2012

By Daniel Bicalho Viegas

Chapa de desgaste revestida com metal duro tem ampla aplicação na indústria, principalmente no segmento de mineração. Usualmente, o revestimento é aplicado em chapas de aço de baixo carbono. Estes aços são os mais comuns devido à sua boa soldabilidade. Paralelamente ao emprego das chapas revestidas, foi desenvolvido um aço de baixo carbono e de elevada dureza (350 a 600HB), com a finalidade de se tornar uma boa opção como chapa de desgaste. Em função da escassez de informações técnicas quanto à aplicação de revestimento em chapas de alta dureza, este trabalho tem como objetivo avaliar a influência do ciclo térmico de soldagem sobre as propriedades mecânicas do aço Hardox® 450. A metodologia experimental consistiu no revestimento do aço Hardox® 450, com dureza da ordem de 450HB. Para o revestimento foi utilizado o processo de soldagem FCAW. Após a soldagem, foi feita análise do perfil de dureza na seção transversal dos corpos de prova. Para avaliação da resistência ao desgaste, foi feito o ensaio de abrasão conforme recomendações da norma ASTM G65-04. De acordo com os resultados obtidos foi possível confirmar que a aplicação do revestimento duro influencia diretamente nas propriedades mecânicas do material.

Aug 17, 2017

By M. E. Hawkins

This Bureau of Mines report provides information on all of the 329 proved salt domes in the Gulf Coastal States and offshore area of the United States. It includes specific data related to location, depth to the cap rock and to the salt, storage facilities for LPG, and production of salt, sulfur, petroleum, and rock related to or associated with the dome structure in the subject area. Also included is a brief history of the salt, sulfur, and petroleum industries as related to the salt domes. Gulf Coast salt domes were the scene of the first discovery of a large deposit of rock salt in North America, the birthplace of the Frasch sulfur industry, and the location of the first large oil gushers that ushered in the modern liquid fuel age.

Jan 1, 1966

The Effect of High Power Nanosecond Electromagnetic Pulses on Selectivity of Pyrite from Arsenopyrite

Sep 13, 2010