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By Isabel F. Barton, Matthew J. Gabriel, CARSON ROBERTS, JOHN LYONS-BARAL, LEON DUPLESSIS, Mark D. Barton

Geometallurgical assessment of orebodies in the mining industry typically relies on bench-scale or lab-based characterization techniques. In this study, we investigate drone- and tripod-based field hyperspectral imaging as a potential addition to the geometallurgy toolkit in multiple applications. This pilot study tests hyperspectral imaging for largescale mineral mapping in and around the active Lisbon Valley copper mine, including natural exposures, previously producing U-V mines, highwalls, dumps, and leaching sites. Tests include different (supervised and unsupervised) mineral data classification methods, varying mineral spectral reference libraries, comparison with ground-truth geological and spectroscopic mapping and sampling, and integration with LiDAR data. The results show that hyperspectral scans can produce spatially registered maps of the distribution of different spectrally active mineral types over dumps, highwalls, leach pads, and natural outcrops. Clays, other phyllosilicates, carbonates, and sulfates showed up particularly well. The sensor was also able to distinguish dry from lixiviant-saturated areas and map different clay types on the leach pads, and shows promise for differentiating types and health of vegetation. These results suggest that hyperspectral imaging, if coupled with robust ground-truthing, can be a useful complement to existing geometallurgical techniques in the mining industry, such as geological mapping, blast hole sampling and automated mineralogy identifications, and handheld spectrometry. In particular, hyperspectral imaging has promise for mapping the distribution of acid-consuming minerals; mapping the distribution of swelling, sliming, and heap-blinding clays; and pinpointing problem areas on heap leach pad surfaces.

Feb 10, 2021

By F Anthes, U Barow

Two tunnels are being bored using a æHydroshieldÆ in section 3.1 of the extension of the Underground railway line 5. At the end of the two tunnels, directly in front of the Hotel Adlon, the shields cannot be retrieved. The steel shell of the shield will be left in place within a sealed concrete block and the reusable components taken out through the completed tunnel. For the first time in Germany, an Underground tunnel is being lined solely by means of UNI rings. BerlinÆs Underground network is 165 km long and has 167 stations. Some 450 million passengers are transported annually. On account of the urban planning modifications that followed reunification, the network has to be adjusted, particularly in the city centre. The most significant project is the extension of the U5 from Alexanderplatz to the Lehrter Bahnhof. After completion, the U5 will be a continuous east-west traffic artery. It will provide a direct link with the new parliamentary and government district, open up new business districts and the cultural centre of the city.

Jan 1, 1999

By Dean Workman

Long extensible conveyor systems are an important option for efficient tunnel excavation where intermediate access is impractical. The conveyor system designed for the Pula Subbaiah Veligonda Tunnel #2 in Andhra Pradesh, India will eventually extend to 19.35km. The Ø10.0m water diversion tunnel will be excavated under India?s largest tiger sanctuary using a Robbins Double Shield TBM. Once extended, the conveyor will be one of the longest single-flight systems ever installed in India, and is expected to offer increased system availability over comparable systems using muck cars. This paper will examine the engineering challenges of long-flight extensible conveyor systems in the areas of belt selection, component design, and equipment location in confined assembly and launch areas

By Gunn S. G, Wilson E. G

Studies by Telecom showed that the existing cable tunnel system in the Melbourne C.B.D. required expansion in order to meet the future telecommunications needs of the City. Due to physical locations of the various telephone exchanges in the CBD, together with a necessity to connect into existing ATC tunnels, a network of low cover small sized tunnels was proposed to maintain and extend the existing telephone cable network. This paper reviews the feasibility studies, design criteria and constructional aspects involved in building 5 tunnels (total length of 1850 m) and 13 chambers (4 open cut and 9 underground)-together with ancillary works, which form part of the new cable tunnel network.

Jan 1, 1981

By Jürg Schlumpf

Concrete is one of the decisive construction materials, also for the AlpTransit Gotthard Tunnel. The client has many requirements, and many are the solution possibilities that concrete systems can offer. Cement producers and concrete admixture manufacturers have been challenged to design and test jointly concrete systems for cast and sprayed concrete. The testing operation followed the scenario laid out by the Gotthard AlpTransit Project management?s instructions ?Testing system for concrete mixes.? Various supplier teams have applied for the concrete systems for sections Amsteg/Erstfeld, section Sedrun and/or sections Bodio/Faido and have also followed through with the tests. As was to be expected, the rate of failed mixes matched the level of the requirements. Thanks to this system, it was nevertheless possible to test complete concrete systems for all sections and to get them approved. The joint ventures tendering for the contracts were allowed to include only approved mix designs in their bids. Workability and durability are of paramount importance for cast and sprayed concrete mixes. Durability is influenced by the chosen mix design where binder concept and well-defined water content, i.e., impermeability, are determinant. Aggregates for AlpTransit are to be considered as given. The concrete mix design also determines workability. Because ambient conditions and also requirements with respect to workability are subjected to change, it is necessary that the mix designs include control measures. The choice and number of components for the concrete systems (cement, additives and admixtures) allow adaptation to changing conditions. For AlpTransit such adaptive measures must meet very strict requirements.

Jan 1, 2008

By MYRIAM FRANCOEUR, JOHN R.R. BOWLING, ADAM MCFADDEN

As duct-fan systems push the envelope of power, length and cost, their design calls for a more comprehensive technoeconomic analysis to ensure they deliver the expected results without failure and cost overrun. This work explores the numerous factors to include in the design of an extensive (semi-)rigid duct-fan system. Besides delivering a given airflow, the system must satisfy component limitations and power constraints during its lifetime. We evaluate the assumptions underlying the positioning of in-line booster fans in a long gapless duct-fan system and propose a strategy for specifying the location and blade pitch of successive booster fans to prevent system failure due to a partial vacuum.

Oct 1, 2022

By J. R. R. Bowling, A. McFadden, M. Francoeur

The abstract discusses the increasing use of extensive duct-fan systems in underground hard-rock mine development. It highlights the challenges of designing these systems, particularly the risk of partial vacuum and the need for careful booster fan positioning. The paper explores factors influencing the design of these systems, including component limitations, operational wear margins, and power constraints. It also defines the concept of partial vacuum and its impact on ventilation ducts. The authors propose an algorithmic approach for specifying the location and blade pitch of in-line booster fans to prevent system failure.

Mar 17, 2022

By Hans Hamrin

Three drill-blast cycles of 3.1 m advance achieved in one working shift of 7.5 hours at the Holsfjorden Tunnel project in Norway. The tunnel, 5235 m long, with a cross section of 8.6 m2, was completed several months ahead of schedule. This remarkable performance was achieved by a crew of 16 men, using machines specially designed for small tunnel excavation. The integration of drilling and charging into one unit, mucking and transport in another, reduced non-productive time considerably. The average cycle time of 140 min made it possible to complete three rounds in one 7.5 hours shift.

Jan 1, 1987

By E. Lovera

ABSTRACT: The current study analyzes the feasibility of an odd operation: to obtain, using a properly tailored drilling and blasting scheme, blocks suitable for the production of dimension stone from tunnel driving. Clearly, a compromise must be found between the rate of progression and the achievement of workable blocks. As a case study, a civil work under consideration in northern Italy was examined. The work was planned to cross a conglomerate that has traditionally been locally exploited for the production of highly prized paving and lining stones with excellent strength and aesthetic features. Natural exposures and mined-out quarries were available for tests. The relevant rock data are given, blast designs are shown (within the limitations of contour accuracy), and the test program is described.

Jan 1, 2011

By James R. Evans

Orange County, adjacent to the populous and industrialized Los Angeles area, is the fastest growing county in California and is second only to Los Angeles County in total population (figure 1). In addition to an equable climate and a burgeoning economy, there is room in Orange County for growth and expansion. Growth over the past decade has resulted in rapid development of industrial tracts, housing areas, and shopping and commercial centers, mostly in former agricultural areas. The value of new building in 1972 was a record amount-over I billion dollars (figure 2). Problems relating to the proper direction of growth are the concern of both government and the private sector. The intelligent and efficient use of areas to be developed requires planning for the conservation and protection of the County's natural beauty and for the orderly development of natural resources. The availability of sand and gravel, which is used in many phases of construction, will be a major controlling factor in the future of the County.

Jan 1, 1974

By H. A. Shaw, H. G. G. Whitton

This paper describes the use of the electric-arc furnace for the production of tough-pitch, horizontal cast copper shapes and the production of copper anodes from tank house anode scrap. This installation is the only one of its kind in the United States. SINCE the initial use of electric-arc furnaces for refined copper melting on a commercial scale at Copper Cliff in 1936, this type of melting has been of extreme interest to everyone in any way connected with copper casting and fabricating. Early in 1948, Kennecott Copper Corp. decided to build an electrolytic copper refinery at Garfield, Utah. One of the major decisions to be made at that time was the type of furnace to be used for melting cathodes for casting into refined copper shapes and for melting anode scrap for the production of anodes. Based on the results obtained from arc furnaces by the Tnternational Nickel Co. of Canada, at Copper Cliff, and by the American Smelting and Refining Co., at Baltimore, coupled with certain important economic factors such as having an adequate amount of relatively cheap power available at the Magna Central Power Plant, high cost of poles and oil in the Salt Lake District, and the lack of natural gas at that time, the final decision was to install electric-arc furnaces rather than the standard type of rever-beratory furnaces. Experience has shown certain parts of the original installation to have been inadequate or in need of modification. Although the present status of arc-furnace melting at the Utah Refinery is far from perfect, nevertheless substantial progress has been made. At the Utah refinery, copper is melted in three 15-ft diam, size "M" Lectromelt furnaces, two of which are used for melting cathodes and one for remelting anode scrap. Each furnace is energized from a 13,800-225 v, 3-phase, 60-cycle, 6000-kva (at 40°C rise) oil-immersed water-cooled transformer. Auxiliary equipment for each refined copper furnace includes a charging machine, launders, ladle, 40 ft diam Walker-type casting wheel, bosh, and inspection conveyor. The anode furnace differs in that it is charged by hand from an elevated platform and the anodes are picked off the 24-ft diam casting wheel by a takeoff hoist and loaded directly into specially designed trailers, Figs. 1 and 2. Electrical Equipment Electric power to operate the arc furnaces is generated at the Kennecott-owned Magna Central Power Station two miles distant and transmitted to the Refinery outdoor substation at 44,000 v. At this point it is stepped down to 13,800 v and carried through concrete-lined underground tunnels to the switchgear and then to the primary side of the furnace transformers. The power is conducted from the Y-connected secondary bus bars of the transformer to the electrode arms by means of 22 flexible copper cable conductors per phase. Each cable has a cross-sectional area of 1,750,000 circular mils, giving a total area of 38,500,000 circular mils per phase. The power is carried from these cables to the three individual electrode holders by means of water-cooled copper bus tubing. The electrode clamps are incorporated in the electrode holders and are released by air pressure working against a spring in the clamp control cylinder. The movement of the electrode arms is either automatic or manual. The automatic control is used during melting and is regulated by three Westing-

Jan 1, 1954

By F. Habashi

"A short account will be presented on the extraction of rare earths from monazite sand, bastnasite ore, and phosphate rock of igneous origin. This includes mineral beneficiation, leaching methods, fractional crystallization [of historical interest], ion exchange, solvent extraction, precipitation from solution, and reduction to metals. INTRODUCTIONOriginally, the term rare earths was only used for the oxides, R2O3, which are similar to one other in their chemical and physical properties and are therefore difficult to separate. Within the rare earth group, the elements scandium, yttrium, and lanthanum differ in their atomic structure from the elements cerium to lutetium (the lanthanides, Ln). Scandium occupies a special position with respect to this classification and its other properties, and therefore does not belong to either of these groups. The rare earth elements always occur in nature in association with each other. The isolation of groups of rare earth elements or of individual elements requires costly separation and fractionation processes owing to the great similarity of the chemical and physical properties of their compounds, which explains why the history of their discovery has extended over such a long period.The word “rare”, when used to describe this group of elements, originates from the fact it was thought that these elements could only be isolated from very rare minerals. Considering their abundance in the Earth’s crust, the term rare is now inappropriate. These elements are lithophilic and are therefore concentrated in oxidic compounds such as carbonates, silicates, titano-tantalo-niobates, and phosphates.The abundance of the rare earth elements taken together is quite considerable. Cerium, the most common rare earth, is more abundant than cobalt. Yttrium is more abundant than lead, whereas Lu and Tm are as abundant as Sb, Hg, Bi, and Ag. For all practical purposes promethium does not occur in nature. It forms only in nuclear reactors."

Jan 1, 2012

By J. F. Mitchell, R. Bainbridge, E. A. Melvin

IN the fall of 1953, The Consolidated Mining and Smelting Co. of Canada Ltd. put into operation a completely new and modern plant for sintering the rather complex assortment of materials which comprise the feed to the Lead Smelter at Trail, British Columbia. This Lead Smelter is one section of an integrated metallurgical plant producing lead, zinc, silver, gold, cadmium and other metals. Since most of the incoming lead concentrate contains appreci- able zinc values, and most of the zinc concentrate similarly contains appreciable lead values, the cross-routing of residues or tails from the respective lead and zinc plants offers obvious advantages in recovery of metals, and has been practiced for many years. A disparity has existed, however, between the output of zinc plant residue and the capacity of the Lead Smelter to treat it, with the result that over the years a stock-pile of residue had been accumulating, and by the end of World War II had reached the formidable total of half a million tons. To treat this stock-pile, in addition to all current zinc plant residues and, of course, the regular quota of lead concentrates, became a prime objective of the Lead Smelter following World War 11. As zinc plant residue plays an important part in the operations to be discussed in this paper, some consideration of its

Jan 1, 1958

By Siegmund Babendererde, Jan O. Babendererde

Extruded Concrete Lining combines technological and financial advantages. The tunnel lining is reliably embedded in the surrounding ground as the fluid concrete is extruded at constant pressure directly behind the TBM supporting the exposed surface. Ground deformation from the TBM passage can be compensated and the ground will be pre-stressed by the extrusion process. Developments in concrete technology permit high speed tunneling by use of a slip formwork attached to the TBM. Realised projects in Milano (Italy), Lyon (France), Frankfurt (Germany) and Akima (Japan) will be demonstrated.

Jan 1, 2001

By D. S. Salonine

Aluminum alloys are widely used in modern industry. Tubes and hollow shapes give great opportunities for structural purposes as well as fluid transport due to their stiffness and lightness, Extrusions on a mandrel or through a bridge die, that requires splitting of the billet with re-welding, produce hollow shapes with varied contours, fins and multiple cavities. Moving and stationary mandrels, mandrel lubrication, tooling for ribbed-tube heat exchangers, and for drilling pipes are considered. Bridge dies can be classified by the bridge position relative to the die face, by mandrel support structure, and by assembly type, The main parameters influencing the quality of the die-welded seams are considered, The difficulties of extruding various alloys through bridge dies are discussed in terms of metallurgical factors, Some approaches to the calculation of the stresses in a bridge are presented.

Jan 1, 2005

By Madeline Mello, Michael Low, Nick Karlin, Bryce Scofield

The LA Effluent Outfall Tunnel is the first tunnel in the United States to incorporate post- tensioning into the precast segmental lining. Several unique components were integrated to ensure that the post tensioning could be carried out successfully in the tunnel, even concurrently with the TBM excavation. This also required the development of new processes both in the casting facility and in the TBM to ensure that the almost 3,700 rings could be successfully manufactured, threaded, stressed, and grouted. This paper will discuss the material selection, fabrication, and installation of, as well as lessons learned from, this first in country tunnel lining.

Jun 23, 2024

By Toshiharu Teranishi

When we apply the Au nanoparticle superlattices to the future nanooptical and nanoelectronic devices, the control of not only the particle size but also the interparticle spacing and symmetry of superlattice are the essential problems to be overcome. First, we developed a novel synthetic procedure to precisely control the particle size of alkanethiol-protected Au nanoparticles in the range from 1.5 to 9.7 nm by the heat-treatment of the small Au nanoparticles in the solid state. Absorption and nonlinear optical properties of alkanethiol-protected Au nanoparticle superlattices were then elucidated. On the other hand, the hexagonal close-packed (hcp) 2D superlattices of small Au nanoparticles with the interparticle spacings from 1.9 to 3.6 nm were successfully prepared by using newly-synthesized ligand for single electron tunneling devices. Finally, various symmetric superlattices, such as chain (2-fold), quasi-honeycomb (3-fold), square (4-fold), etc., of Au nanoparticles could be produced by making use of interligand interactions or some templates.

Oct 1, 2003

By K. Kovári, G. Anagnostou

Slurry and EPB-shield tunnelling have been successfully applied worldwide in recent years. Under extremely unfavourable geological conditions, however, face instabilities may occur. The present paper aims at a better understanding of the mechanics of face failure. For the case of slurry shield, attention will be paid to the time-dependent effects associated with the infiltration of slurry into the ground ahead of the face. Related topics, such as the stand-up time and the effect of the excavation advance rate, will be discussed. In the case of an EPB-shield, a distinction will be drawn between fluid-pressure and effective pressure in the chamber. The effective pressure can be visualized as a “grain to grain” contact pressure between the muck and the ground at the face. The water pressure in the chamber reduces the hydraulic head gradient in the ground and, consequently, the seepage forces acting in front of the face. The face is thus stabilized both by the direct support of the pressurized muck and by the reduction of the seepage forces in the ground. The paper includes normalized diagrams which allow the assessment of tunnel face stability.

Jan 1, 1997

By K. D. Eng, W. T. Tierney

"During the past century, the development of vehicular transportation has benefitted tremendously from the performance improvement in engines in a situation where low-cost, plentiful fuel supplies were the order of the day. Engine advances were enhanced by and also dictated fuel modification to better adapt the energy source to the power plant.In discussing the several aspects of the change in approach from ""an engine and its fuel to a fuel and its engine"", the authors touch on the following areas:1. Description of an engine concept that provides the needed flexibility in fuel appetite at good efficiency to cope with future requirement s.2. The constraints placed on liquid fuel resource energy utilization efficiency by special engine-required fuel properties and the fuel efficiency of the various engine types available.3. Future vehicle engine fuel sources. This review will put into perspective the problem associated with the net energy available from future fuel sources under extensive research and development at present.4. A brief review of test data to show that fuel-tolerant and fuel-efficient engines are viable and that, in a fuel-resource-limited future, they can be a ""light at the end of the tunnel.""The Texaco Controlled Combustion System (TCCS)The TCCS is a unique means for stratified charge operation of an internal combustion engine in such a manner as to eliminate the requirement for octane or cetane number specification for the fuel. Octane rating is an empirical engine test method that evaluates a gasoline's resistance to spontaneous ignition or ""knock."" Cetane is based on a different engine test, which determines a diesel fuel's ease of spontaneous ignition . High cetane number enhances cold starting and permits high-speed diesel engine operation. As one would expect, the fuels in current use cover a band when the two values, octane and cetane, are plotted against each other."

Jan 1, 1982

By Luisa Perez, Carlos Perea

El método de explotación por subniveles es uno de los más utilizados en operaciones mineras de mediana y gran escala, como es el caso de la minería de zinc en Perú. Para seguir la secuencia de explotación, este método requiere el relleno de los caserones vacíos, como por ejemplo el relleno en pasta, el cual se produce mediante la mezcla del relave producto de la planta concentradora de mineral con un 3.5 % de cemento, con el fin de que dicho relleno actúe como pilares de gran dimensión que aporten el sostenimiento necesario a la mina (0,8 MPa). Sin embargo, esto genera una dilución con el mineral a explotar al momento de avanzar en los tajos aledaños. Por ese motivo, y por la necesidad de lograr la automatización de la operación minera, se decide evaluar el relleno detrítico cementado, evaluación que se realiza mediante el análisis de resistencia, estudios de factibilidad, rendimiento en costos, aumento de productividad y seguridad en la operación. El resultado son valores máximos de resistencia de los pilares de 1,6 MPa, que evitan la dilución y mejoran el porcentaje de recuperación de mineral.

Sep 20, 2019