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By Pasi Korkeakoski

There are about 400 multi-storey buildings founded on wooden piles in the city centre of Turku in Finland. Soil conditions are variable from hard rock to very soft clay. Due to the soil conditions and ground water lowering there are basically four different types of underpinning projects. Under dimensioned cohesion piles in a deep clay layer, decaying cohesion piles, a combination of these two reasons and decaying end bearing piles in a thin clay layer area. Many different execution methods have been used such as impact driving, jacking and drilling and combinations of these.

Jan 1, 2000

The work to be described is part of a comprehensive research on the influence of impurities on the properties of lead. The author had previously compared an electrolytic lead containing less than 0.002% total impurities with a commercial lead containing 0.008% impurities (excluding oxygen) and had shown that the former recrystallised more readily than the latter under the same conditions of cold work and annealing. This difference in properties was attributed to the difference in purity. Electrolytic lead containing only 0.0005% total impurities has been prepared and cast in vacuo. Some interesting effects have been obtained by working and annealing this lead, and by adding silver to it. The preparation of this lead, and the effects obtained thereon, are described in this paper. Thepaper is divided into the following sections:(I) Preparation of electrolytic lead.(II) Vacuum Casting.(III) Effect of Cold, Work and Annealing on two Electrolytic Leads, having 0.002% and 0.0005% Total Impurities respectively.1 Research Fellow, Dept. of Metallurgy, University of Melbourne.2 Proc. Aust. lnst. Min. Met., 1932, 87, 145.

Jan 1, 1934

By Joe Maher

Adequate mine roof support to insure the safety of men and equipment is essential to successful mining. It is also expensive, amounting to more than one-fifth of the total mining cost at the White Pine mine. Cost effectiveness is therefore a prime consideration in developing optimum roof support. Roof bolt length is an important cost factor. This Phase II work compared uniform four-foot length Resin Bolts with the hitherto standard alternating four-foot and six-foot Resin Bolts, aiming at more cost-effective roof bolting. The data generated under this Phase II show that there is no discernible difference in the roof support given by uniform four-foot, and by alternating four- and six-foot, Resin Bolts in the relatively difficult ground selected for a severe initial test comparison; subsequent data from less difficult ground led to the same conclusion, namely no discernible difference between four-foot and four-six foot bolting.

Jan 1, 1975

By Mike Boissonneault

It was three years ago when the “storm of the century” had taken a firm grip over the Pacific West Coast and inland areas. At the Big Sky ski resort in Montana on Christmas morning two ski patrollers set out to perform an explosives “hand charge” avalanche control mission that would see only one return. It has been difficult to determine exactly what happened. Investigators do know that there were three separate and consecutive attempts to light a safety fuse, when it had apparently been burning since the first attempt. Time ran out after the third attempt. Although this accident has had a profound impact on North American avalanche control programs, I am sure it pales in contrast to the shock and grief experienced by family members who lost a loved one.

Jan 1, 2001

A GREAT deal of attention has lately been given to the discussion as to the education required for engineers, and especially for mining engineers. The Institute of Civil Engineers has had a committee's report on it which has come to some interesting and valuable conclusions.The Institute of Mining and Metallurgy had a few years back a very long discussion on the subject, and the subject appears to be one of perennial interest to similar societies. Two recent addresses by Prof. Kernot, as president of the Victorian Instituteof Civil Engineers, are among the most interesting and practical of the contributions to the discussion. Engineers seem to feel either that the coming generation has not the same capacity to benefit by the training that has made themselves what they are, or that such training has turned out in themselves inefficient men, and that they must consequently struggle to obtain a better one for their successors. For not only is there a desire to extend existing instruction to cover the advances of science, but there seems to be a general desire also to make a completely radical change in the methods.It is not necessary to observe that education does not mean the imparting and acquiring of information, but rather the cultivation of the faculties so that the best use can be made of them and of any information acquired. For instance, a man is not educated who has by heart his lectures and the contents of his text-books, but that man is who remembers little of the actual wording of his text-books, but is able to find anything required in them...

Jan 1, 1909

By I. Mc Dougall

Finite element models were generated of two submerged arc furnaces of different geometries. A 48MW circular furnace and a 68MW 6-in-line rectangular furnace were studied. The electrodes, raw material, slag and molten metal were included in the model. ANSYS/Multiphysics was used to predict the current density distribution in the electrodes, raw material, slag and molten metal as a result of the three phase AC current. The effect of the electrode immersion on the current path was studied. The ?proximity effect? caused a pronounced asymmetry in the electrode currents in the circular furnace, whilst the electrode currents in the rectangular furnace exhibited radial symmetry. The current distribution in the melt in both furnaces indicated that the bulk of the current flows between phases. The current density is greatest between electrodes. Results were compared to qualitatively similar published work, operating experience and results of furnace dig-outs.

Jan 1, 2007

By J. O. Marsden

Over the past eight years, Phelps Dodge (a subsidiary of Freeport-McMoRan Copper & Gold, Inc.) devoted a significant amount of effort to the development of a suite of processes for the effective hydrometallurgical treatment of copper sulfide concentrates. This effort resulted in the development of high-temperature (>200ºC) and medium-temperature (150° to 165ºC) pressure leaching processes. Specific configurations of both processes have been commercially demonstrated at Phelps Dodge?s facility in Bagdad, Arizona. This paper reviews in detail the chemistry of medium-temperature pressure leaching of copper concentrates and reports on the process development work conducted by Phelps Dodge and others for this technology. This paper is Part I of a four-part series on this technology. Part II covers the development of medium-temperature pressure leaching and direct electrowinning technology; Part III considers the large-scale demonstration of the MT-DEW-SX process at Bagdad, Arizona; and Part IV addresses the development and design of a full-scale commercial application at Morenci, Arizona.

Jan 1, 2007

By J. C. Haptonstall

The Bismark Mine is located in northern Chihuahua, Mexico, 150 km (95 miles) southwest of Ciudad Juarez (Fig.1). The ore deposit was discovered in 1979 and was placed in production in 1992. The production rate is about 2.4 kt/d (2650 stpd) from an ore reserve of 8.5 Mt (9.3 million st). Grades currently average about 8% zinc, 0.5% lead, 0.2% copper and 50 g/t (1.46 oz/st) silver. Substantial inflows of water into the underground mine complicate the operation. Complex metallurgy poses another challenge for the operators. Bismark is a joint venture with 90% participation by Minas Penoles, SA de CR of Mexico City and 10% participation by Promociones Industriales Banamex, S A de C V (PIB S A) of Mexico City. Anew company, Minera Bismark, SA de CV was formed to operate the property. Cyprus Minerals was a 40% participant in the joint venture but, in early 1993, sold its share to Minas Penoles. The Bismark Mine is one of the largest new underground mining projects built in Mexico during the last 10 years. It is the country's fifth largest underground metal mine and provides about 1 % of the world's zinc supply at about 50 t/a (55,000 stpy). Bismark is a trackless operation with overall productivities of 7.6 t/manshift (8.4 st/manshift). The 2.4-kt/d (2650-stpd) concentrator started up in March 1992.

Jan 1, 1994

By R L. Brathwaite

Previous paleodepth studies of low-sulphidation epithermal Au-Ag deposits in the Coromandel region indicated that economic gold mineralisation was generally limited to a depth zone of 100 to 400 m below the paleosurface. Notable exceptions are Waihi and Karangahake, where ore shoots extended to depths of about 750 and 900 m respectively. These studies have been extended to include Au-Ag, Hg and Sb epithermal deposits in Northland and the Taupo Volcanic Zone. The main paleodepth indicators used are sinters and hydrothermal eruption breccias, hydrostatic pressures estimated from homogenisation temperature measurements on fluid inclusions, and hydrothermal alteration mineralogy. Also the occurrence of lacustrine and fluvial sediments is an indicator of the paleosurface at their time of deposition. Selected paleodepth indicators have been compiled and mapped in a GIS environment. The distribution of the paleodepth indicators are used to define regional variations in erosion levels, and may be useful in predicting areas most likely to preserve the optimum depth window for gold deposition. In the Coromandel region, regional stream sediment geochemical data has also been used to broadly define erosion levels in terms of Zn, Pb and Cu representing deeper base metal zone mineralization and Hg and Sb representing shallower cinnabar and stibnite mineralisation. The interpretations of paleodepth and potential reconstruction of paleosurfaces are limited by the paucity of data, poor age control on the paleodepth indicators and the epithermal deposits, and marked relief and complex stratigraphy in the volcanic terranes.

Jan 1, 2003

By S. Nikolic, G. M. Stieper, D. P. Mallah, B. J. Hogg, P. B. Voigt

Copper feed materials processing is becoming more challenging, due to an incremental increase in the mineralogical and compositional complexity of these feeds. These complex and polymetallic feeds are now becoming more common and many sites have been forced to re-evaluate their operating strategies to process these materials at cost competitive rates, whilst meeting ever more stringent environmental regulations. Most operations must first evaluate the merits of pyrometallurgical and hydrometallurgical treatment routes. Although there are multiple copper smelting technologies available, only top-submerged lance (TSL) technology, supplied by Glencore Technology as ISASMELT™, has been applied in the real world to consistently and successfully smelt complex materials in integrated metallurgical facilities such as Glencore’s Kazzinc Ltd. operation in Kazakhstan, Umicore Precious Metals Refining in Belgium and Aurubis AG in Germany. Glencore Technology also offers hydrometallurgical processing, through the Albion Process™ technology, opening up viable flowsheet options previously not possible for these complex feeds. This paper describes a number of real world process flowsheets at global operations and Glencore’s own operations at Mount Isa and Kazzinc Ltd., which process complex feeds. These flowsheets integrate the ISASMELT™, Albion Process™, ISACONVERT™, ISAKIDD™ Tank house, and bottom blown oxygen cupel (BBOC™) technologies to provide an effective process solution for the treatment of complex polymetallic feeds to produce metallic copper and associated by-products. INTRODUCTION Traditional smelters and those built in recent times within the bulk smelting hubs of the world have been designed to treat standard/clean concentrates. In recent years the processing of complex polymetallic sulfide concentrates and the recycling of secondary copper and derivatives of waste electrical and electronic equipment, such as e-scrap, have become a focus for numerous companies (Alvear & Nikolic, 2013). Processing of these complex feeds, characterized by relatively high levels of minor elements (over 5% of elements such as arsenic, antimony, bismuth, lead and zinc) is more challenging. Facilities not designed for these types of materials may require significant modifications or a change in smelting technology to treat them. Often operations find themselves re-evaluating the merits of pyrometallurgical and hydrometallurgical treatment routes for their sites through a number of factors:

Jan 1, 2019

By Enrique Fernandez

M-30, Madrid’s inner ring, covers 42 sq km of the city centre where one million people reside. It was constructed in several phases during the sixties and the eighties. The design criteria applied to those phases were different and were not always homogeneous with urban roads with lighting regulation as well as speedways. These areas had a heavy concentration of access and exits and there had been made many changes on the number of traffic lanes which has caused heavy traffic congestions and high accident rates. The environmental impact and noise pollution in residential areas are also consequences of M-30. The Madrid Major took a decision at the beginning of the present legislation, based on socio economic and environmental evaluation; rebuild the M-30 with the following sustainable mobility principles: Underground transfer of a considerable portion of the main ring and some of its links replacing some parts of the surface with new green areas in order to reduce the environmental impact. Increase the traffic capacity, improving the traffic continuity and fluidity and eliminating the lighting regulation areas, which is one of the main congestion problems currently. Increase the traffic safety with clear signalling information panels and avoiding difficult maneuvering. Redesign the links with the high capacity radial highways and other connecting lanes of the city. The project is worth 3.7 billion Euros. In 2007, when the construction is completed, it is expected will save 14 million of journey hours that represent 4.5 million Euros saved in fuel consumption per annum, There will be a very significant reduction of 35,000 tons of CO2 in terms of pollution and 400 less car accidents. Those values will increase even more in the following years. The areas beside Manzanares River, running parallel to the M-30 on the western side of Madrid, will be highly enhanced. Better water quality and the recovering of the green areas existing in old times will also return for the citizen’s enjoyment. TUNNEL CROSS SECTION OF CALLE 30 SOUTH BY PASS One of the major challenges of the new Calle 30 is actually not only the related to the main road but also to the link with the A-3, with highway to Valencia. This link is currently the most congested area and has one of the highest traffic densities of Spanish roads, with more than 250,000 vehicles/day. The remodelling of this area is the principle objective of the South by-pass. The tunnel is the only answer for this by-pass as the road alignment will go among buildings. A twin tube design, one for each direction, with three lanes allowing the circulation of both, light cars and heavy trucks, is the solution that has been

Jan 1, 2007

By I. A. Mwamba

Titanium sponge, which is almost pure titanium, is extremely ductile and not easily processed into titanium powder. One method of producing powder is the hydride-dehydride (HDH) process, where titanium sponge is hydrided to form brittle titanium hydride (TiH2). Titanium hydride is easily milled to produce powder and is then dehydrided to form Ti powder. In this work, titanium hydride powder obtained from titanium sponge was used as a starting material for blending and mechanical alloying with elemental powders. Firstly, titanium hydride powder was blended with aluminium elemental powder to produce a homogenized powder, which was then compacted and sintered to produce powder metallurgy compacts. Secondly, titanium hydride powder was mechanically alloyed with aluminium elemental powder and then compacted. The mechanically alloyed powder was characterized in terms of particle size distribution, morphology and microstructure. In both blending and mechanical alloying, the green compacts were characterized by assessing the green density, while the sintered compacts were characterized by their sintered density, microstructure, and hardness. The two processes have resulted in the formation of TiA13 intermetallic compound. It was established that by simple mixing and homogenizing, titanium hydride can be used as a starting material to produce powder metallurgy components in which porosity is a benefit rather than a problem, much akin to metallic foams. From the products obtained in the TiHz-Al system, it appears that titanium hydride can be used as a precursor in mechanical alloying. However, the possible formation of complex hydrides may introduce detrimental properties, and needs to be further investigated. For the production of non-porous components, it would be advisable to dehydrogenate the TiH2 powder before milling i.e. producing titanium powder by the hydride-dehydride (HDH) method. Keywords Mechanical alloying, titanium hydride, titanium aluminide and blending

Jan 1, 2011

By K Kermanshahi, J Allen, MáHilden, M Powell, S Mwansa, S Palaniandy

Approximately 420 VertiMills« (VTM) have been installed in mineral processing plants throughout the world, mainly in tertiary and regrind applications plus several in secondary grinding duties. Metso Minerals (Metso) and the Julius Kruttschnitt Mineral Research Centre (JKMRC) have commenced a collaborative research program in stirred milling technology focusing on mill performance evaluation, model development and scale-up methodology. Industrial VTMs are being assessed using a consistent circuit survey protocol to evaluate the performance of VTMs in comminution circuits. The survey protocol includes identification and modification of sampling points, appropriate sampling techniques, controlled circuit stability, and best sample analysis practice. To initiate this study four surveys were conducted in the tertiary grind circuit in the Ridgeway Concentrator at Cadia Valley Operations (CVO) that treats the full circuit throughput of over 800 tph. To deal with the high feed rate the site opted to lead the world in the application of stirred mills by installing the largest VTM, at 3000 hp (2240kW) in closed circuit with a hydrocyclone bank. On average the operating work index was 13.1 kWh/t, reducing the secondary grind product by 40 - 50 ¦m to the required 80 to 100 ¦m range. The applied specific energy is relatively low in these low-intensity stirred media mills at 2.7 kWh/t. The size specific energy was 24.2 kWh/t-75¦m. Based on the survey and operating data the VTM circuit is performing well in this high-throughput tertiary grinding application, producing a sub-100¦m product.CITATION:Palaniandy, S, Powell, M, Hilden, M, Kermanshahi, K, Allen, J and Mwansa, S, 2013. VertiMill« - Development of circuit survey and performance evaluation protocols, in Proceedings MetPlant 2013 , pp 162-175 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By Laura McNally

In 2006 McNally International Inc. in a Joint Venture partnership with Aecon Constructors was the successful bidder on two York Region Tunnel Projects: Bathurst Collector/Langstaff Trunk Sewers; and YDSS Interceptor Sewer 19th Avenue Project. These projects comprise a total of 13 kilometres of 2.74 meter finished diameter tunnels and are both part of the York Durham Sewer System (YDSS). Both contracts require the use of EPB tunnel boring machines with a precast concrete segmental liner. The following provides an overview the two projects.

Jan 1, 2008

Allis Mineral Systems ARCO Coal Company Buckley Powder Co. CALCO, Inc. Coal Magazine Colowyo Coal Company Continental Conveyor & Equipment Company Crane & Hoist Sales Cummins Southwest, Inc. Energy West Mining Company Paul J. Epley FMC Corporation The Falkirk Mining Company Fleischli Oil Co., Inc. T. J. Gundlach Machine Company Halbach & Braun Harnischfeger Corporation Hemscheidt Corporation Hyatt Regency Beaver Creek Jennmar Corporation Joy Technologies, Inc. K&P Sales Engineers, Inc. Kennametal, Inc. Kerr-McGee Coal Corporation McLanahan Corporation National Coal Association The North American Coal Corporation Northwestern Resources Company Peabody Coal Company Phillips Machine Service, Inc. Pincock, Allen & Holt, Inc. Pittsburg & Midway Coal Mining Co. Roberts & Schaefer Company Rust Tractor Company Salt River Project Santa Fe Pacific Coal Corporation Schroeder Industries Shearson-Lehman Brothers Southern Pacific Transportation Stamler Corporation Trapper Mining Inc. Wagner Equipment Company Western Energy Company Wheeler Machinery Company

Jan 1, 1992

By R. G. Cawthorn

The vertical distribution of platinum-group elements (PGE) in the Merensky and UG2 chromitite Reefs is highly variable, but does follow certain general patterns that allow the testing of geological models. In the Merensky reef, historically popular geological representations and interpretations have suggested that the mineralization occurs in a pegmatitic pyroxenite bounded by two chromitite layers. However, there are now enough published exceptions to this relationship to expose its fallacy. The vertical distribution of the PGE depends largely upon the separation between these two chromitite layers or the absence of one chromitite layer. Where separation is small or only one chromitite layer is present, there is considerable PGE mineralization in the footwall below the pyroxenite and lower chromitite layer. With increasing separation between the two chromitites, the mineral¬ization occurs progressively higher in the succession, and tends to track the upper chromitite layer. The view presented here is that the entire Merensky package is comprised of three events of magma emplacement, in which each has produced variable reaction with, and erosion of, the footwall, causing recrystallization of pyroxenite into pegmatitic pyroxenite. The magma then produced a chromitite layer followed by pyroxenite. Each chromitite layer is associated with some mineralization, which was extensively complemented by the subsequent formation of a sulphide liquid carrying PGE that trickled down through about 1 m of permeable crystal pile. The sulphide liquid formed after, not coincident with, the pyroxenite layers. The distribution of PGE in the UG2 chromitite shows up to three upward depletion sequences of PGE, also suggesting three events. The PGE are associated only with the chromite. The contribution from a sulphide liquid is considered to have been minimal for two reasons. Cu and Ni are extremely low in the UG2 which would not be expected if sulphides had been present. Also, by analogy with the Merensky, downward trickling of sulphides would have caused some PGE to be present in the footwall. There are some PGE in the footwall, but only where remnants of chromitite occur, and the hanging wall is lacking in PGE. In the northeastern Bushveld the UG2 chromitite is thinner than elsewhere, and there is a UG3 chromitite layer, not present elsewhere, that has a high Pt/Pd ratio. It is surmized that in the rest of the Bushveld the UG3 only appears to be absent because it has merged with the UG2 to produce the high Pt concentration at the top of the composite UG2. The non-accumulation of the package of pyroxenite-norite-anorthosite between the UG2 and UG3 in the northeastern Bushveld, which is not seen elsewhere, creates an interesting challenge to the formation of silicate layering in the complex. The mineralization in the Platreef is not addressed here. Keywords Bushveld complex, Merensky Reef, UG2 chromitite, geological evolution.

Jan 1, 2011

By Steve Kral

Reducing the cost per ton and increasing productivity are key factors in a mine’s profitability. Mining companies can do little about commodity prices. So to keep a mine operating at a profit, management must reduce costs and improve worker and equipment productivity in every facet of a mining operation. From mining to crushing to processing, mine management is constantly seeking new methods and technologies to improve the way it mines minerals. And it is willing to borrow techniques used by other operators.

Jan 1, 2002

By E. F. Schnitzer, S. R. Mamoyac, P. J. Wampler

During 1996 and 1997, Oregon experienced flooding on a scale not seen in many years. Some gravel pits located near rivers experienced erosion and, in several cases, breaches between the gravel pit and the river. Initial evaluation of several sites that experienced breaches indicates that impacts to the river system are complex and vary significantly from site to site. The impacts to the adjacent river system may be viewed as both positive and negative. Several floodplain-mining sites in Oregon located in areas of historic river flow have reverted to active riverbed. In many cases, state and federal fisheries biologists and university researchers see the resulting increase in channel complexity and habitat as favorable. The Oregon Department of Geology and Mineral Industries – Mined Land Reclamation Program (DOGAMI-MLR) is performing additional studies of the impacts to the off-channel areas that resulted from the 1996 floods. More data is needed to make sound floodplain decisions regarding mining.

Jan 1, 1999

By W. J. Schlitt

The development of forced aeration as an approach to enhancing copper sulfide leaching is traced from its earliest development up to present day operations using this technology. Both large-scale field tests and commercial operations are covered. The historical portion is preceded by an introductory discussion of the role of air (oxygen) in sulfide leaching. Sufficient aeration may be achieved via naturally induced convective airflow. However, cases are identified where this is insufficient, leading to retardation of the sulfide leach rate. For these situations, forced aeration may be beneficial. The historical portion of the paper focuses on the major field tests that have been conducted in Montana, Nevada and Utah, along with commercial operations in the United States, Australia, Chile and Peru. The paper concludes with some general comments about the applicability of forced aeration, which are based on the information developed to-date.

Jan 1, 2006

By Donald C. Strimbeck

The Bureau of Mines designed a down-fired refractory-lined combustor that efficiently burned pulverized coal to produce a gas suitable as working fluid for an open-cycle gas turbine. The gas contained relatively little carbon, so the load on the ash-separation equipment was significantly reduced. Moreover, reduction in carbon content of the gas increased the average density of the solid particles making them more amenable to removal by centrifugation. Centrifugal-type separators failed to remove sufficient ash; however, to limit blade wear enough to achieve operating periods generally deemed necessary for commercial practicability.

Jan 1, 1969