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By Valentín Pamo

El presente trabajo describe los procesos y equipos que permiten la extracción de metales preciosos de la refinería de Ilo en condiciones agresivas, obligando a investigar materiales resistentes a la corrosión. Asimismo, se presentan alternativas que aseguren la continuidad de las operaciones en el proceso productivo de dicha refinería.

Sep 9, 2007

By Chris G. Leach

"Abstract A seven storey Northbridge area of Perth, Western Australia presented residential apartment complex located in the an opportunity for a novel application of Cutter Soil Mix technology (CSM). The development included a two-level basement for car parking which covered the full site area. However, the basement was also required to extend under an existing single story heritage building. Soil conditions comprised 2m of fill overlying medium dense to dense sands that in turn were overlying a very stiff clay stratum at approximately 14-16m depth. The ground water table was located at a depth of approximately 1m below the natural surface level.A site boundary consisting of a reinforced CSM retention system and was designed and installed to allow the excavation to proceed to basement level. Two rows of temporary soils anchors or inclined struts were required to achieve this. A CSM support system for the heritage building was also designed and constructed to provide temporary support during excavation and permanent construction works. The brief for the contract works emphasised that it was vital that settlements of the heritage building be kept within strict limits.CSM is a relatively new introduction to the Australian construction market, using a modified trench cutter to mix a binder slurry with in situ soils, generally to form cut-off walls, retaining walls and soil improvement works. This project is understood to be first application of the CSM for underpinning work in Australia.This paper discusses the site background details leading to the decision by the client to adopt CSM technology, and the design and construction aspects to meet the challenges offered by this project.Introduction190 Newcastle St is a 7-level residential apartment complex located in the Northbridge area of Perth, Western Australia. The development includes a 2 level basement for car parking, which covers the full site area. The basement also extends under a single story heritage building, which remained in-situ throughout the building works.A site boundary retention system was required to allow the excavation to basement level to proceed. In addition, a support system for the heritage building was required to provide temporary support during excavation and permanent construction works."

Jan 1, 2014

By Paul Harvey

Following initial discovery in 1991, BHP Billiton Diamonds Inc opened Canada?s first diamond mine, the Ekati Diamond Mine TM (Ekati) in the Northwest Territories on October 14th, 1998. Four short years later on November 29th, 2002, saw the opening of North America?s first underground diamond mine - the Koala North mine. Nestled between the original Panda open pit and the new Koala pit which is in the early stages of production, Koala North represents the only underground kimberlite mining venture in arctic conditions outside the new underground mines being developed by ALROSA in the Yakutsk region of eastern Russia. Extensive underground kimberlite mining has been practiced in the Republic of South Africa for much of the 20th century and continues today. Underground mining represents a key component of the long term business plan for the Ekati. As various open pits reach their economic limit, continued recovery of high value ore at depth is dependent upon the ability to productively mine the kimberlite pipes by underground methods. As a function of its location, size, and value, the Koala North pipe is ideally positioned to host the first underground mine at Ekati . In addition to being a production source for the operation, Koala North is designed as a learning mine, from which to gain valuable experience in preparation for the potential mining of other larger, higher value pipes by underground methods in the future. Fortuitously Koala North was available for development so the learnings could be integrated into the Panda mine design prior to completion of the Panda pit. Establishing our first underground diamond mine, and applying the open benching mining method in arctic conditions brings a unique combination of mining challenges together in a harsh climate and remote environment. This paper examines the design and establishment of the Koala North mine. Discussion includes experiences gained from the first year of development, production start-up, and provides a brief overview of our potential underground future at Ekati .

May 1, 2003

By Patrick Frenette

The Goldex Mine is an underground gold mine using a unique mining method where a single very large stope is being created. In order to maintain stability of the walls and roof of the stope which is 450m, 250m high and up to 120m thick, ore is left in the stope as long as possible and acts as backfill would do. At many occasions during the mining sequence, the walls will be exposed on height ranging from 30 meters up to 250 meters. A monitoring system comprising in-stope laser surveys, a seismic system and an array of extensometers and sloughmeters all remotely connected to surface is used to observe the shape and evolution of the stope. This paper will focus on the results obtained following some of the large blasts and on the long term monitoring of the stope.

May 1, 2011

By Mitchell L. Fong

The Bay Area Rapid Transit (BART) District will be extending BART service south along an 8.7-km (5.4-mile) -long corridor in the city of Fremont, California as part of the Warm Springs Extension (WSX). The WSX project will link the existing BART system to the future BART to San Jose extension. A segment of WSX is located in Fremont Central Park (referred to as the Fremont Central Park Subway Project). The Fremont Central Park Subway is considered the most complicated and geotechnically challenging portion of the project with an underground subway box being constructed near the active Hayward Fault which is capable of ground motions up to 0.75 g and is located in an aquifer which is used for water storage and supply. Soil-structure interaction analysis was used in the design of the subway box to resist deformations due to earthquake ground motions. A water-tight excavation support system has been designed to allow subway box construction while minimizing impacts to the aquifer.

By J. D. Stone

This paper briefly reviews the adequacy of existing management theories and practices and the managerial proficiency or competency in the South African mining industry. The investigation revealed that existing management practices are totally inadequate to enable all employees on all the levels of the mining industry to achieve the results required from them, in all aspects, at all times. As a result, the South African mining industry is gradually losing its long standing reputation as a relative cheap, competitive, and reliable supplier of minerals to the local and global markets. According to some prominent management authors and theorists, an all-inclusive unified management theory does not exist at present. In this paper the authors summarize the main aspects of a newly developed comprehensive, practical, and integrated management method. It is believed that the application of this method would significantly improve the future performance and competitiveness of the South African mining industry

Jan 1, 2010

By Mark Maday

As part of the I-94 North-South Corridor reconstruction program, the Wisconsin Department of Transportation (department) is reconstructing the Mitchell Interchange in Milwaukee, Wisconsin. Located on the south side of Milwaukee near Mitchell International Airport, The Mitchell Interchange interconnects I-94, I-43 and I-894. Reconstruction began in 2009 with the letting of the first advance contract for local crossroad bridge reconstruction. A second advance contract for construction of collector-distributer roads on each side of the I-94 mainline was completed in 2010. The main contract involving reconstruction of the core of the Mitchell Interchange was let in the summer of 2010, and is scheduled to be completed by the end of 2012. The core contract includes construction of three cut and cover tunnels along two system interchange ramps. Construction of the three tunnel structures is on the critical construction path. The contract includes an interim contract completion date that requires the tunnels to be open to traffic by the end of 2011. A top down method of construction using drilled shaft secant piles for the sidewalls of the cut and cover tunnel structures was selected as the preferred structure type to address subsurface and construction schedule challenges. The department identified in pre bid coordination that no cost reduction incentives would be reviewed or accepted for changes in tunnel wall type. A major component of the tunnel structures requires the installation of 1,500, 4-foot diameter secant piles. This paper presents mitigation strategies to manage construction risks associated with the installation of the secant piles including; prequalification of the secant pile subcontractors, requirement for use of full depth temporary casing, a site specific quality control plan, specifying drilling equipment, and developing a geotechnical baseline report for this critical component of the Mitchell Interchange reconstruction project.

Jan 1, 2011

By C. M. Harrer

The location, features, quality, and extent of iron ore deposits are evaluated in this Bureau of Mines report. The results of pioneer beneficiation on Wyoming taconites and their success are discussed along with developments in the iron-ore mining industry, markets, and economics. Market potential, transportation, resource developments, taxation, cost of iron ore enterprises, and the future of Wyoming iron resources are evaluated. Although occurrences of iron ores in Wyoming were known prior to 1870, early production to 1900 was as a nonferrous metallurgical flux and as mineral pigment for paints. In 1901, the Hartville-Sunrise hematite deposits were available to the Western iron and steel industry and in 1962, the first western taconite operation was placed in production at Atlantic City, Wyo. This investigation disclosed the probability of other large iron deposits in Wyoming. Taconite in the Bradley Peak area of the Seminoe Mountains has a potentiality of 100 million tons; that in the Owl Creek Mountains may prove very large also. Pioneer beneficiation testing has been included, and results have been generally encouraging. Research continues on the large titaniferous magnetite deposits of Albany County, Wyo. At present high-density titaniferous magnetite is being mined and processed at Iron Mountain for heavy-aggregate and as a sized coating for underwater pipelines. Ample mineral raw materials needed for mining and processing Wyoming iron ores are available. Investments for iron-ore processing plants will generally be large, particularly for taconite and titaniferous magnetite.

Jan 1, 1966

By C. M. Harrer

The location, features, quality, and extent of iron ore deposits are evaluated in this Bureau of Mines report. The results of pioneer beneficiation on Wyoming taconites and their success are discussed along with developments in the iron-ore mining industry, markets, and economics. Market potential, transportation, resource developments, taxation, cost of iron ore enterprises, and the future of Wyoming iron resources are evaluated. Although occurrences of iron ores in Wyoming were known prior to 1870, early production to 1900 was as a nonferrous metallurgical flux and as mineral pigment for paints. In 1901, the Hartville-Sunrise hematite deposits were available to the Western iron and steel industry and in 1962, the first western taconite operation was placed in production at Atlantic City, Wyo. This investigation disclosed the probability of other large iron deposits in Wyoming. Taconite in the Bradley Peak area of the Seminoe Mountains has a potentiality of 100 million tons; that in the Owl Creek Mountains may prove very large also. Pioneer beneficiation testing has been included, and results have been generally encouraging. Research continues on the large titaniferous magnetite deposits of Albany County, Wyo. At present high-density titaniferous magnetite is being mined and processed at Iron Mountain for heavy-aggregate and as a sized coating for underwater pipelines. Ample mineral raw materials needed for mining and processing Wyoming iron ores are available. Investments for iron-ore processing plants will generally be large, particularly for taconite and titaniferous magnetite.

Jan 1, 1966

By Dave Stefanuto

Voisey?s Bay Project Components ? Mine/Mill Port In Labrador ? Mini Plant in Mississauga ? Demonstration Plant in Argentia ? Supply Vessel (Umiak1) ? Transshipment Facility (Quebec) ? Concentrate Handling & Transport to Sudbury/Thompson ? Cobalt Refinery Upgrade (Thompson) Project Setting ? The Project is on the traditional lands of the Labrador Inuit and the Labrador Innu ? Canadian courts have held that Aboriginal peoples in Canada possess special rights to traditional Aboriginal lands Those rights can include requiring resource developers to enter into Impacts and Benefits Agreements (IBAs) on traditional lands to set forth how lands can be used and benefits to be received by Aboriginal people

May 1, 2006

A review of historic mining information and geological literature pertaining to the Alpine Mine, Lyell Goldfield has been completed. As a result of this work the Alpine reef is inferred to be associated with an upright anticline with a sub-horizontal axis. Structural profiles prepared from limited underground data indicate that the reef is subparallel to the eastern limb of the anticline and cuts across the western limb. Reassessment of structural mapping completed by the New Zealand Geological Survey indicates that Greenland Group metasediments within the Lyell Goldfield are folded into a series of opposed assymetic folds with sub-horizontal axes. It is suggested that the anticline which harbours the Alpine Reef is located on the axis of a synclinorium. Along the western limb of the synclinorium the subsidiary folds have steep west dipping limbs and shallow east dipping limbs (western sense of assymmetry) whereas shallow west dips and steep east dips are typical of the eastern limb. The notion of quartz mineralisation occupying the axis of a synclinorium is contrary to the situation in the Reefton Goldfield where quartz mineralisation is affiliated with folds associated with an anticlinorium. Historic mine data reveals that below No.4 Level the quartz-gold mineralisation, in the Alpine Mine, occupied a steeply dipping ore channel. The strike of the channel was to the northwest and within this structure the are shoots plunged to the north at approximately 40¦. Archival mine plans show that two quartz bodies, the North and South Blocks, were present at No. 4 Level. Although the North Block was followed down to No 14 Level (530 m vertically below the surface outcrop) the South Block was only mined as far as No 7 Level. Sampling on No 7 Level together with the results of trial mining suggest that the grade of quartz underfoot in South Block is low. Information from the Mines Statements and mapping undertaken by the Gold Prospecting Scheme reveals that faulting had a profound influence on the intregity and extent of the Alpine Reef. The reef occupies a Inajor shear zone but little is known about it. It is also apparent that below No 7 Level the reef was progressively shattered by faulting and this may be the chief reason for the decrease in grade in the lower levels of the mine. No substantive facts are available about wall rock alteration effects adjacent to the Alpine Reef Still this is not surprising considering that comments on the mineralised pug envelope and breccias adjacent to the mined quartz shoots at the Globe - Progress Prospect were omitted from contemporary publications. In spite of this the existance of sulphide bearing reef casing lithologies cannot be completely dismissed since 9.15 m of 'reef track' has been reported in Reids No 2 Level.

Jan 1, 1996

By Ludovic Charpentier

Production of metallic wires directly from liquid jets would avoid drawbacks of extrusion (space needed, damaging, cost?) and enable recycling. But liquid jets tend to break, due to capillary instabilities, unless a solid layer (coating or start of solidification) surrounds it. We recently developed a process to produce tin wires, cooled by water flow parallel to the jet. Superficial oxidization of tin produces a glass coating around the jet. Studies showed the length of wires increased when increasing speed of tin jets, and that water average speed should be the closest possible to the jet one to have smooth fibers. Producing 1 mm diameter wires is possible. The length of wires is limited by the experimental setup, which does not provide possibilities to coil the wire. Most of other metals do not generate glass-like oxides. The lack of coatings makes it necessary to reduce the capillary instabilities to obtain fibers.

Jan 1, 2006

By M. A. Trevits, I. R. Houlison, A. C. Smith, T. P. Mucho

Timely and rapid intervention to underground combustion events (fires, explosions, and spontaneous combustion) is the key to the successful control of the mine atmosphere and restoring of a coal mine to production. The focus of this paper is the utilization of a GAG 3A jet engine system to combat either large out-of-control fires or to render an entire mine inert when access to problem areas is difficult or impossible. This system is based upon a Soviet designed agricultural jet engine which consumes aviation fuel with oxygen (O2) from the intake air and exhausts combustion gases, primarily carbon dioxide (CO2) and water (H2O), along with the nitrogen (N2) from the air and small amounts of carbon monoxide (CO) and hydrogen (H2). The system is designed to approach stoichiometric combustion (ideally, pure burning that scavenges all the oxygen from the intake air). Therefore, these exhaust gases are almost entirely “inert gases”- i.e., gases which do not contribute to, and in fact, can suppress the combustion process due to the lack of oxygen. Other methods to inert mine areas have been used in the US and internationally, but these methods usually use low flow inertisation equipment or methods. Use of these low-flow inertisation equipment and methods has been successful in proactively rendering gob areas inert and has the ability to inert the entire mine workings. Due to the low flow rate, however, a substantial period of

By Q. G. Reynolds

The presence of dust and fume suspended in the freeboard region is a common feature of the operation of direct current (DC) plasma smelting furnaces. This occurs primarily as a result of the use of fine feed materials together with the open-arc, open-bath operation of such smelters, and is exacerbated by the high velocities and turbulent mixing of the gas in the vicinity of the arc jet. Dust and fume losses into the furnace off-gas system can be significant in some cases and may have economic, operational, and environmental impacts on the process. A computational modelling study is presented in which the concentration of dust material was considered as a continuous field subject to a governing partial differential equation. Settling behaviour was calculated as a function of particle size, local gas/plasma temperature, and other physical properties. Development of the coupling between the concentration field and a magnetohydrodynamic description of the arc is shown, and the resulting models were used to compute various aspects of the behaviour of the concentration field in the arc region for a variety of furnace conditions. Time-averaged as well as transient models of the arc were used to generate the results presented. Qualitative case studies produced several practical suggestions for furnace operation, including increased dust capture by the bath when feed ports are located closer to the electrode, and the possible effects of feed segregation in the furnace freeboard based on dust particle size and density.

Jan 1, 2015

By R. N. Powell

The Pipeline ore body was discovered in March 1991. The construction of the new mine and mill did not start until early March of 1996. Upon completion of permitting and corporate project approval, the 289 million USD project was “fast tracked”. The commissioning began 11 months after start of construction and the project ended 40 million USD under the budget figure. The objective of this paper is to review and highlight the Pipeline Project history from discovery, design, lawsuits, permitting, and re-design through to current - 1998operating practices. Particular emphasis will review the process design, design mistakes, and design successes. The paper will review project history, feasibility, design concepts, operator training, construction, financial and the current operation. Additional discussion will review what design features worked and which did not work within the process plant.

Jan 1, 1999

By Paul Doherty

Expansion of the global piling industry has been coupled with significant research efforts investigating the mechanisms controlling pile capacity. Static pile design has transitioned from total stress approaches toward effective stress design, with associated improvements in predicting pile performance. As a result, the available literature is heavily skewed toward static capacity prediction. However, when considering piles offshore, the majority of loading is not static but highly variable and cyclic in nature. This paper outlines the additional factors that require consideration for cyclic pile design, including elevated loading rates, cyclic displacements and capacity degradation. A review of the literature identified a number of cyclic pile testing programs which are collated in this paper. General trends are established through comparison of the tests within the database and the conditions where cyclic loading is most likely to be a concern are identified. In particular, loading conditions which involve full plastic shear reversals are seen to cause the most extreme cyclic damage, with the degraded capacity as low as 31% of the precyclic static capacity. The underlying mechanisms which can result in cyclic damage are explored, with particular attention given to the pore pressure response, radial stresses, shear transfer and particle reorientation.

Jan 1, 2009

Recently discovered Carboniferous bentonites are variable in charadeI and thickness, but being altered aeolian, ash-fall tuffs, they are probably extensive. Most are the Ca-montmorillonite type without the natural swelling characteristics of the Wyoming deposits, but their situation, thickness, and response to beneficiation through cation exchange may give them some potential as sources of future economic deposits.INTRODUCTIONLoughnan and See (1959) gave an account of bentonites and fuller's earth deposits of New South Wales. The most likely potential industrial sources were those occurring in the uppermost formations of the Newcastle and Singleton Coal Measures (Permian) in the Hunter Valley and deposited during epochs not marked by strong contemporary vulcanicity.One feature of the record of known occurrences at that time was the absence of bentonites from the thick volcanic sequences of the Carboniferous, but since this paper appeared, many bentonite beds have been discovered by the writer in the Carboniferous facies formerly known as the "Kuttung Series".The purpose of this contribution is to report briefly on the occurrence, genesis, mineralogy, and economic potential of these deposits which augment possible sources of bentonite near major industrial centres on the eastern seaboard.The potential world demand for bentonite would increase markedly with the trend to pelletization in the steel industry, if its use in this field became more general. More detailed mineralogical studies will be presented in later publications.STRATIGRAPHIC DISTRIBUTIONBentonite occurs at irregular intervals throughout a thick sequence of dominantly continental, plant bearing strata...

Jan 1, 1965

By S. T. Kok

This paper presents a case study in West Malaysia for passive piles failure in very soft marine clay in open excavation. In this particular case, the thickness of the very soft marine clay ranges from 5 m to 7 m (16 ft to 23 ft) from the ground surface. Preliminary site investigation reported SPT ?N? value of zero for the very soft marine clay. The design was based on a deep foundation utilizing driven piles to support the superstructure. During pile cap construction, the piles were subjected to uncontrolled open excavation, inducing bending moment in the piles, resulting in some cracked and broken piles. Analyses were carried out using an existing three-dimensional finite element code with a non-linear soil model to predict the response of these piles during excavation. Finally, the predictions of pile responses during excavation were compared satisfactorily with the observed results.

Jan 1, 2009

By R. Q. Shotts

Factors of geological structure and occurrence of coalbeds, plus the resulting mining conditions, have required more care in preparing coals in Alabama than in most other districts almost since mining Alabama coals began. For this reason, literature on these coals may be interesting to those in areas where prime coals have been mined out, and thinner and less regular beds must now be exploited. This literature review has been arranged in order of subject matter. Some references have been listed more than once, but each separate review is limited to the material pertaining to the subject matter being discussed. For those seeking specific information, the authors have indicated which items repeat material and which items are most complete or specific. Geology, preparation, and carbonization of coal have been reviewed the most frequently.

Jan 1, 1963

This report is the 25th in a series summarizing Bureau of Mines research and technologic work on coal and related investigations, and the 7th of these reports to be issued on a calendar-year basis.3 It reviews briefly work in progress during 1960, and furnishes references to publications by Bureau personnel during 1960 and also to a few older papers that were not cited in prior reports of this series. Details about some of the researches mentioned can be found by referring to the publications cited in the footnotes or in the further list in the Miscellaneous section; other phases of work are reported here for the first time and will be covered in more detail by later publications, Coal programs of the Bureau of Mines extend over the wide range of theoretical and applied studies indicated by the table of contents. Fundamental research on coal structure and on the properties of coal will, over a period of time, increase the general knowledge about coal Which scientists and engineers may use in answering practical questions and in solving problems in the mining and utilization of coal. More applied studies are conducted in connection with the developement and evaluation of new mining techniques and the effective processing and utilization of coal and of coal products. Health and safety activities, analyses of coal being mined, and technical advice and assistance to Federal agencies in connection with fuel and boiler-water problems are among the practical services handled by the Bureau.4 5

Jan 1, 1962