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By Sarah Holtz Wilson, Kenneth Rossi, Carl R. Handford, David F. Tsztoo

The East Bay Municipal Utility District’s Claremont Tunnel is an 18,000-foot long water tunnel that crosses the Hayward Fault zone near Oakland, California. It was originally completed in 1929. This project involved the construction of a bypass tunnel through the fault zone, including an enlarged vault section designed to accommodate up to 8.5 feet of horizontal offset. Ground conditions encountered included sheared and crushed serpentinite and clayey fault gouge, and presented specific challenges for construction. A special excavation and support sequence used concrete-backfilled side drifts as foundations for the vault steel sets. It also allowed for a 20-foot-wide top heading and bench excavation in soft and squeezing ground conditions.

Jan 1, 2007

By E. Laine

Rock density determinations are necessary for ore resource evaluations from estimated block grades in g/t. Rock density depends on the mineral composition and, thus, it is specific for each rock type. The rock density distributions for different rock types are often symmetric. Hence, the arithmetic mean is a good approximation for the average density for lithological units. However, there may exist spatial variation in density values due to alteration, fracturing and original heterogeneities such as layering. This study compares the kriged density model with the one with constant density values for different lithological units in the evaluation of metal amounts in rock blocks. The case study consisted of rock densities measured from the drill cores at Ahmavaara PGE deposit in northern Finland. The used Ni contents were simulated in accordance with the spatial distribution of rock densities. The Ni amounts in 2x2x2 m3blocks are higher for the kriged densities than for the average densities. The difference is increasing with the increasing metal amounts due to the nonlinear correlation between Ni content and rock density. The final effect on the resource estimation depends on the cutt off grade and prices of the metal, for example, for a very valuable metal the small differences are significant

Jan 1, 2003

By John G. Henning

The Porcupine Joint Venture operates the Dome Mine in South Porcupine, Ontario. Dome underground began production in 1910. It is the longest continuous operating gold mine in Canada, producing in excess of 15 M ounces. More than 900 underground stopes have been mined and hundreds of miles of drifts, sublevels and raises developed. Underground mining methods included shrinkage, cut and fill and longhole. Not all stopes were backfilled upon completion, particularly the longhole stopes. The Dome open pit was designed above the underground mine workings such that, as the pit is excavated, it intersects underground drifts and stopes. Potential operational problems associated with the interactions between the stopes and the pit walls may occur, necessitating pit wall redesign, ground support installation and operational rescheduling. Each intersection of the pit with the underground mine workings is closely evaluated to maintain a safe working environment and wall stability. This paper discussed how risks to pit wall stability are assessed, mitigated and monitored.

May 1, 2004

By Jaidev Sankar

The dream of constructing the new Second Avenue Subway in New York has finally become reality as the first construction contract package is currently underway. This first contract requires the construction a TBM Launch Box in the middle of Second Avenue from which a Tunnel Boring Machine (TBM) will bore two tunnels south to 63rd Street. This paper will discuss the design of this contract and how construction has progressed including preparation, site constraints, utility construction and com-munity impacts while highlighting the challenges of working in an urban environment. It will also discuss moving forward on this major project outlining the remaining contract packages including their scope and status.

The discussion in this paper centres on examples of mining that are drawn mainly from the coal mining industry. The intention is to review the opportunities that exist for incorporating environmental planning into mining industry practice in New Zealand. The coal mining examples serve to make some general points which have some application for many types of mining.

Jan 1, 1981

By Natalie White, Joel Asp, Allyz Kramer

"Minnesota has robust reclamation standards and have proven results in the taconite mining industry. Reclamation of overburden spoils, lean ore spoils and fine tailings from taconite production has generally been successful on the Iron Range, using a low input standard reclamation practice. Success at reestablishing vegetation on these landscapes is likely due to fairly favorable chemical and physical properties (e.g., few limitations due to acidic generating materials, metal toxicities and water and nutrient holding capacities). However, coarse tailings reclamation has proven more difficult, presumably due to lower nutrients and challenges with moisture holding capacities. Research efforts conducted since 1990 have struggled to develop a reclamation strategy for coarse tailings that meets the Minnesota Mineland Reclamation Rules, Chapter 6130. However, new breakthroughs in scram mining technologies are producing fine and coarse tailings that have not been encountered nor reclaimed in northern Minnesota. Scram mining in Minnesota is defined as those mining operations that produce natural iron ore concentrates. Innovative research is underway to investigate and determine successful reclamation strategies to reclaim scram mining tailings from these scram mining operations. The research program is conducted through collaboration with SEH, Prairie Restorations, Inc. (PRI) and Mining Resources, LLC with funding support from the Iron Range Resources and Rehabilitation Laurentian Vision Partnership minescapes grant program.The research program was divided into three phases:Phase I. Bench-scale testing to identify successful treatments to reclaim and restore scram tailings through evaluating surface soils amendments, viable seed mixes and plant germination, growth and densities. Phase I was completed in early 2015.Phase II. Field-scale pilot trial to test larger scale effectiveness of the treatments deemed successful in Phase I and test various vegetative assemblages and planting techniques focused on the unique challenges with scram tailing basins. Phase II was completed in late 2016 with a summary monitoring report.Phase III. Produce a technical report of results for the research undertaken in this study, as well as compile prior reclamation results used during previous Minnesota iron mining reclamation projects on tailings basin applications. Phase III was completed in 2017 with a summary monitoring report and recommendations."

Jan 2, 2018

By Anthony D. Hammond

The use of geographic information systems (GIS) as a tool to analyze and display data is gathering momentum in the mining industry. Of particular interest is the capability of GIS to link spatial features and tabular data. The application of GIS in underground mining discussed here concentrates on four technical areas. They are land ownership and mineral claims, exploration management, production and mine safety.

Jan 1, 2002

By C. Tan, C. Detournay

Wellbore stability is a major concern for drilling in naturally fractured formations. The infiltration of drilling mud into the fractures is a factor, which may compromise wellbore integrity due to the loss of strength experienced by the fractures. The reduction in the fracture frictional and cohesive properties is attributed to weakening of the infill materials and lubrication of fracture asperities by the mud filtrate. One way to investigate the influence of mud infiltration on wellbore stability in fractured formations is to use a numerical modeling approach. A requirement for the numerical model is the ability to predict the region of mud infiltration. This paper describes a numerical technique to model the extent of mud infiltration for application in coupled fluid-mechanical simulations in densely fractured rock masses using the computer code, UDEC. Several factors are considered including fracture pattern, in-situ stresses, reduction in joint frictional angle and cohesion, viscosity of the mud filtrate and fracture plugging. Results of numerical simulations are presented to illustrate the technique and show the influence of these factors on the extent of mud infiltration. Un des problèmes importants posés par le forage en milieu fissuré saturé, est celui du maintient de la stabilité du puit. L’infiltration de boue de forage dans le massif peut avoir pour effet de réduire les propriétés frictionnelles et cohésives des fractures et de compromettre ainsi la stabilité du puit de forage. Le radoucissement des propriétés des fractures est attribué à la dégradation du materiau de remplissage et au pouvoir lubrifiant des boues. L’analyse numérique offre un moyen d’investiguer l’influence jouée par l’infiltration de boue sur la stabilité du puit. Un des critères de sélection du modèle numérique sera son pouvoir de prédiction du domaine d’infiltration de boue. Cet article décrit une technique numérique permettant de modéliser l’infiltration de boue de forage dans le cadre de simulations hydro-mécaniques, en milieu à haute densité de fractures, effectuées avec le logiciel de calcul UDEC. Parmis les facteurs tenus en compte, on trouvera la nature du réseau de fractures, les contraintes in-situ, le radoucissement en friction et cohésion des joints, la viscosité de la boue et le bourrage des fractures. Des résultats de simulations sont présentés pour illustrer la technique et montrer l’influence de ces facteurs sur la taille du domaine d’infiltration de boue. Bohrlochstabilität ist ein wichtiger Aspekt für das Bohren in geklüfteten Gebirgsformationen. Das Eindringen der Bohrlochstützflüssigkeit in die Klüfte kann die Bohrlochintegrität wegen des Verlustes der Festigkeit des Kluftsystems gefährden. Die Reduktion der Reibung und kohäsiven Eigenschaften ist der Schwächung der Kluftfüllung und der Schmierwirkung der eingerungenen Stützflüssigkeit in Bezug auf die Kluft-Asperities geschuldet. Numerische Berechnungen sind ein Weg zur Untersuchung des Einflusses der Infiltration der Bohrlochstützflüssigkeit auf die Bohrlochstabilität in geklüfteten Gebirgsformationen. Eine Voraussetzung für numerische Modelle ist die Fähigkeit den Bereich der Infiltration der Stützflüssigkeit zu prognostizieren. Diese Publikation beschreibt ein numerisches Verfahren, um die Reichweite der Infiltration von Stützflüssigkeiten mittels fluid-mechanisch gekoppelter Simulationen im engständig geklüfteten Gebirge mit dem Programm UDEC zu modellieren. Verschiedene Faktoren, wie Kluftmuster, Gebirgsspannungszustand, Reduktion von Kluftreibungswinkel- und kohäsion, Viskosität der Stützflüssigkeit und Rissabdichtung wurden untersucht. Ergebnisse numerischer Simulationen werden präsentiert, um die Vorgehensweise zu illu

Jan 1, 2003

This Bureau of Mines report describes research on methods of assuring the continued safety of mine electrical power distribution circuits through reliability and quality assessment of the protective devices, innovative inspection techniques for these devices and the circuits themselves, novel applications of trolley line circuit breakers, and computer modeling of distribution systems to determine the proper ratings for cables, power sources, and circuit protective elements. Battery charger safety is included.

Jan 1, 1979

By Probert D. H, Wright E. A, Taylor B. L

A general description of the geology of the Southern Coalfield is given. The relationship between the Illawarra Coal Measures, the overlying Triassic and the underlying Upper Marine Series, of Permian age as are the Coal Measures, is briefly explained and thestratigraphy of each is described. The eight coal seams are then treated in slightly more detail as to their thickness, quality, areas of distribution and best occurrences.In the last few years each of the authors has been concerned with one phase or other of the stTucture of the field in detail or in mining operations with the result that it is now possible to name a number of monoclines, anticlines, domes and synclines defined in detail. A minor quantitative study has been made of faults and dykes with regard to form, direction intensity and inter-relationship. It seems probable that with the further collection of data a more detailed study in these matters will be of considerable value to the economy of mining in the Southern Coalfield.

Jan 1, 1958

By Christian Divis

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Jan 1, 2002

By B. S. Van Gosen

In recent years, U.S. regulatory agencies have placed emphasis on identifying and regulating asbestos dust exposures in the mining environment, with a particular focus upon industrial mineral deposits in which asbestos occurs as an accessory mineral. Because asbestos minerals form in specific geologic environments, only certain predictable types of industrial mineral deposits can potentially host asbestos mineralization. By applying a basic knowledge of asbestos geology, the costly and time consuming efforts of asbestos monitoring and analyses can be directed towards those mineral deposit types most likely to contain asbestos mineralogy, while saving efforts on the mineral deposits that are unlikely to contain asbestos. While the vast majority of industrial mineral deposits in the Western United States are asbestos-free, there are several types that can, in some instances, host asbestos mineralization, or be closely associated with it. These industrial mineral deposits include a few types of aggregate, dimension, and decorative stone, and some deposits of chromite-nickel, magnesite, nepheline syenite, olivine, rare earth elements, talc, vermiculite, and wollastonite.

Jan 1, 2009

By E. Özberk

Uranium minerals are often associated with iron minerals, and during the hydrometallurgical processing of the uranium ores, iron plays several significant roles. The presence of Fe(III) in solution promotes the oxidative acid leaching for the recovery of uranium. The control of the distribution of impurities in milling and refining is also affected by dissolved iron. When rejected from the process streams, iron usually collects other impurities and contributes to the stabilization of the wastes for final disposal. These roles of iron, as they relate to current uranium processing operations, are discussed in detail, and some broad and historical perspectives are also presented.

Jan 1, 2006

By Troy Williams, Chris Preston, Ian Lipchak

"Underground blasting operations are challenging from the standpoint of the distribution of explosivesenergy representative of ring blasting. Energy from both shock and pressure regimes of commercialexplosives may appear concentrated in the collar region of a typical ring blast and diluted at the toes of holes due to the oblique geometries of blastholes. The non-homogenous nature of ore in whichexplosives are distributed via drillholes, adds to the complexities of generating particulate profiles from fragmented material with consistencies that are predictable from blast pattern to blast pattern - well suited for specific underground handling equipment and mill processing. In an ideal world, it would be the blasting operations themselves that represent the primary crushing mechanism, or at least mitigate mechanical crushing that can comprise a large component of the cost in generating suitable muck. This paper presents a dynamic break view in 3D that allows a planner to visualize the potential break zone around a blasthole generated by an explosive load using a Kleine field. Simple as it sounds, this methodology provides information that can be used in conjunction with cavity monitoring surveys (CMS) to potentially judge dilution due to overbreak as well as recovery for a typical blast. As examples, there are two break geometries that are examined regarding circular breaks and elliptical breaks around blastholes. Using a Kleine field to define break, a planner generated isosurface can be generated and compared to CMS data for calibration and prediction, using AEGIS 3D ring design software."

Jan 1, 2016

By R. E. Gilmore

Introduction The Sydney coal-field extends for a distance of thirty miles along the northeastern coast of Cape Breton island. At a central focal point at the tip of the south arm of Sydney harbour, seven miles or so in from the Atlantic ocean, is the city of Sydney, with Port Morien to the southeast and Sydney Mines to the north . Mining centres along the ocean coast between these points include Birchgrove, Reserve, Glace Bay, and Waterford. The field is divided into three districts or 'basins', namely, Morien basin to the south, Glace Bay in the centre, and the Lingan-Sydney Mines basin to the northeast. The eastern and western portions of the latter are known as the Lingan and the Sydney Mines basins, respectively. Six distinct coal seams are described as existing in the Morien basin, nine in the Glace Bay basin, and six in both the Lingan and the Sydney Mines basin. Although known by different names in the several basins, a definite continuity of the seams has been established.

Jan 1, 1933

By D. S. van Vuuren

Titanium bearing resources can selectively be chlorinated at temperatures below 200°C if the Ti02 in the feed is nitrided before chlorination. However, the nitriding reaction is highly endothermic, requires highly reducing conditions, is only thermodynamically favourable at elevated temperatures, and is affected by mass and heat transfer restrictions. At the required processing conditions, problems might also be experienced with sintering and with melting of slag forming components in the raw materials. A test programme was undertaken to study the effects of raw material type, temperature, gas composition, bed depth, carbon to raw material ratio and residence time in order to simulate conditions required for scaling up a nitriding process. In contrast to previous experience with low-grade titanium-bearing slag containing about 30% Ti02, ilmenite and chlorinateable slag do not form melting phases under the studied nitriding conditions and hardly sintered at all. Both feed materials can readily be nitrided with conversions in excess of 90% at temperatures around 1300°C and using bituminous coal as reducing agent with fixed carbon in excess of 1.1 times the stoichiometric requirement. The conversion decreases as the bed depth of the feed material increases and the N2/CO ratio in the gas decreases. Analysis of the relative rates of mass and heat transfer into the reacting beds of ilmenite and slag showed that the heat transfer rates are more limiting than the mass transfer rates. In order to increase the throughput that can be achieved in a kiln, it would be necessary to take special measures to enhance the heat transfer rates into the mass of reacting material. One such a measure is to pre-form the mass of reacting material into thin-walled, hollow brick shapes prior to introducing it into a kiln. Depending on bed depth, temperature and N2/CO ratio, required residence times in the high temperature zone of the kiln can vary between about 6 and 10 hours. Keywords Titanium dioxide, titanium nitride, carbo-thermic, reduction, ilmenite, slag, tunnel kiln, residence time.

Jan 1, 2011

By M Donghi, G Ramage, A Barnes

As the mining landscape continues to transform, the challenge of accessing deeper orebodies quickly and safely is becoming a frequent topic of conversation amongst those in the mining industry. The rapid development of underground mine entries to gain earlier access to deeper orebodies is an ever-present challenge to mine owners and contractors. Overcoming this and providing economical solutions to unlock the value in these deeper deposits is a challenge that should be confronted.In 2013, Redpath Australia Pty Ltd (Redpath) commenced construction of what would be the first of two drifts excavated through the use of a tunnel boring machine (TBM) in Queensland’s Bowen Basin.The excavation and development of the two drifts (declines) was completed as part of a contract for underground mining services between Redpath and Anglo American at the Grosvenor Coal Mine Project in Central Queensland, located approximately 5 km north of the town of Moranbah. Having recently completed the drift development, this paper will extend on the early writings of Donnelly, Ramage and Donghi (2014) and provide detail on the operational achievements, advance rates, threats, opportunities and learnings during the excavation of the two declines: the conveyor (CV) drift and the transport (M&M) drift.CITATION:Ramage, G, Donghi, M and Barnes, A, 2016. Experiences gained through tunnel boring machine decline development, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 695–712 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By Tianjiao Luo

The electroless copper plating process for continuous carbon fiber using CuSO4?5H2O as the main salt and formaldehyde as reducing agent was experimentally studied, including the effects of pH values and concentration of chelating agents, stabilizing agents and reducing agent on the electroless plating process. The surface morphology and the composition of coating were investigated by means of Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS), and deposited the coating thickness was measured by way of dissolution. The results indicated that the pretreatment of carbon fiber before plating was so important. This pretreatment could prevent the formation of the black cores, furthermore, it could form many active absorption cores with Ag as the center on the carbon fiber surface. Used the optimized parameters in this process, which led to a stable solution for plating, a homogeneous copper coating was conducted with the carbon fiber plated with favorable mechanical performance and high adhesion strength.

Jan 1, 2006

By A. D. Mukherjee, H. N. Bhattacharya

Middle Proterozoic sulphide ore mineralisation occurs in isolated blocks of the NE-SW trending Delhi fold belt composed of Delhi Supergroup rocks. The Ajari-Basantgarh-Pipela belt forms part of the longest, widest and westernmost tectonic unit of the Delhi fold belt and consists of amphibolites, metapelites, quartzites and carbonates. The metapelite lenses and associated amphibolites host pyritic copper mineralisation. Mineralisation takes the form of sheet-like bodies consisting of ore lenses of various sizes interlayered with host or associated rocks. Massive, banded and disseminated varieties of ore are found. Pyrite is dominant with subordinate chalcopyrite and sphalerite. Pyrrhotite, galena, cubanite, mackinawite, marcasite and freibergite constitute the minor minerals. The characteristic features of the ores suggest a possible correlation with Besshi-type deposits, and the closely associated amphibolites are interpreted as low-K tholeiites of a fore-arc setting

Jun 19, 1905

By Karsten Zimmermann

Surface deformation monitoring is required all over the mining industry. For example oil and gas companies need this information to support exploration and production activities and to detect impacts from surface subsidence of existing hydrocarbon fields. Also opencast mines require large area information of subsidence due to dewatering of the overburden. Because of this, a lot of surface deformations measurements with GPS or traditional geodetic measurement techniques have been conduced during the last decades. This paper presents the actual capabilities to analyze GPS data using the state of the art Bernese GPS Software for GPS post processing. A new way of monitoring subsidence is a combination of GPS and satellite InSAR data. Considering this it is hoped that a combined strategy will permit receiving overall more information by integrating high point density of InSAR and accuracy of GPS. DMT is one of the leading actors on GPS services especially for monitoring surface movements from underground activities e.g. mining, water pumping or oil and gas exploitation. The paper will discuss preferences and problems of this approach on results of a current project of DMT.

Jan 1, 2008