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By Walter Ensinger

Working safely means working cost-effectively. Every "dangerous occurrence" and - even more so - every industrial accident causes disruptions in the planned course of construction. Besides moral and legal obligations, economic aspects are therefore also factors motivating increased efforts towards optimal prevention: improvements in work safety and protection of health are wise investments! Ever since its earliest days, the European Federation of Foundation Contractors (EFFC) has made this subject one of its key objectives and therefore set up a Safety + Environmental Working Group, in which experts from the member organisations exchange national experience and develop proposals for "best practices". The paper presents current developments and results from the work of the S+E WG with particular reference to the project "Ideas for Safety Improvement".

Jan 1, 2006

By K. Englehardt

J BERESFORD introduced the subject of the paper which is the use of polymeric slurries to support the sides of diaphragm wall and bored pile excavations during construction. In the opinion of the authors the use of a suitable polymeric fluid offers financial and technical advantages compared with traditional bentonite based slurries. Under quiescent conditions a support slurry must have the following properties. - sufficient viscosity to support the sides of the excavation, to prevent infiltration into soils and to hold loose soil particles in suspension. - when agitated it should thin quickly to assist pumping transfer and cleaning and allow free passage of the grab or drill. - viscosity should be low enough during concreting to facilitate placement but high enough to prevent contamination of the concrete.

Jan 1, 1991

By J. C. Loretto

"OPENING REMARKS Yesterday and today we have heard some very interesting papers on operating matters and some of you are probably wondering what we are now doing talking about Communications in Plant Design. Let me tell you! Before the techniques we have heard being discussed can be used, there has to be a properly operating plant. It is certainly a fact that many mineral processing plants achieve only limited success and a number of them can even be said to be failures. Some of you sitting here are probably living with operating problems that are clue to errors in the design.If the histories of these problem plants are examined, it will be found that in many cases, the necessary skills were available during the period of the plant design. There was extensive operating know¬ledge together with a full range of project expertise. Why then the failures? In a substantial number of cases it can be traced to the old, old problem of communications. As plants get bigger, money costs more and smooth startups become more important, it becomes less and less economic to fix up any design errors during plant operations.During our careers in mineral processing, nearly all of us will be involved in at least one plant design and I feel that it is as well if we understand some of these communication difficulties that can lead to a problem plant. There is little point in us being experts in mineral processing if the knowledge we have acquired doesn't somehow get incorporated into the plant.I would, therefore, like to present this short paper that mentions a few of the significant communication problems that can occur during the design of mining and mineral processing plants, together with some thoughts on answers to these problems."

Jan 1, 1973

By V. E. Edlund

As part of a research program for recovering alumina from domestic nonbauxitic resources, the Bureau of Mines investigated a lime-sinter, caustic leach technology for anorthosite. This report discusses the unit operations--feed preparation, sintering, and leaching. Acceptable pellets for the bench-scale sintering studies were prepared from mixtures of minus 200-mesh anorthosite and limestone using water alone as the pelletizing agent. Heating pellets at 1,270° to 1,360° C for periods of 0.5 to 2 hr, followed by a 15-min soaking period at 700° C and cooling to room temperature, produced a sinter that dusted to more than 90 pct minus 65 mesh. The weight ratio of limestone to anorthnsite was critical in producing sinter exhibiting good dusting and leaching characteristics. A ratio of 2.0 was optimum for the bulk samples of anorthosite and limestone used in this research. Leach solutions from lower ratio sinters were unstable; gelation became progressively more severe with higher ratio sinters. Leaching the dusted sinter with 10-pct Na2CO3 at 60° C extracted 85 to 90 pct of the alumina in a product solution containing about 50 g/l A1203. Leach residue in contact with pregnant solution tended to set up as a rigid gel as a result of cementation, comp action, and gelation. The presence of a calcium-sodium zeolite [(Cn,Na2)6?(Al2Si04)12?27-3OH20] in the ungelled residues seemed to be the main difference between gelled and ungelled residues.

Jan 1, 1982

By E. Ringdalen

Keywords: Pyrometallurgy, research, Norway, SINTEF, NTNU The Norwegian Ferro-alloy Industry and the model for research cooperation between SINTEF, NTNU, and the Norwegian ferro-alloy industry is presented as an introduction. The research within pyrometallurgy is illustrated by examples from characterisation of Mn-ores and characterisation of carbon materials. Examples from studies of reaction mechanisms in laboratory- and pilot-scale experiments are presented, in addition to an example of industrial off-gas measurements. Education possibilities at NTNU are also described.

Jan 1, 2011

By E. H. Herron, J. H. Perry

Mathematical simulation of reservoir behavior may be used to help understand reservoir processes and to predict reservoir behavior, thereby leading to the most economically desirable form of exploitation. In addition, simulation can be used as a tool for reservoir description to learn more about the physical nature of the reservoir and the mode of primary recovery. This use is essential in most reservoir studies and represents one of the more significant applications of simulation. Prediction of reservoir behavior provides information concerning displacement efficiency, optimum well locations, and the comparison of alternative producing processes. Since oil, water and gas all commonly occur in many reservoirs, a simulation that takes into account the simultaneous flow of three immiscible phases is a prerequisite for obtaining such information. Furthermore, a simulation that describes this flow in two dimensions provides the capability of evaluating combination gas- and water-drive reservoirs with either an areal or a cross-sectional description. Many reservoir problems require such a simulation. The objective of the research described here was to develop a mathematical model and associated computer program for accurate, efficient, and economical prediction of the reservoir flow of three phases in two-dimensional geometry. Several authors have discussed multidimensional reservoir simulation of two phases.l-3 Gottfried et al.' presented an analy- sis of three-phase simulation in one dimension. Fagin and Stewart" and Garrett6 have discussed the simulation of three-phase flow in two dimensions, but their solution techniques were different from the method discussed in this paper. In particular, previous models and computer programs have usually involved either fewer capabilities or inefficient and less rigorous descriptions resulting in limited applicability. In the following sections, we present a description of the model, an evaluation of the method, and the application to reservoir problems. Additional and supporting material is presented in the Appendix. The Three-Phase Model General Description The three-phase model consists of the mathematical description of the flow of oil, water and gas in a reservoir. Conceptually this description considers flow in all three space dimensions, but in the subject simulator it is assumed that no flow occurs in the third dimension. The model includes the effects on reservoir behavior of fluid and rock compressibility, viscosity, gravity, capillary pressure, relative permeability and gas solubility. Within the two-dimensional restriction, the reservoir considered may be completely heterogeneous and anisotropic. The differential equations governing multiphase, multidimensional flow in a reservoir are too complex to be solved analytically, so they are approximated by a system of finite difference equations and solved

Jan 1, 1970

By Paul Eger

The use of wetlands to treat mine drainage has become increasingly common, particularly as more information is available on their operation and construction. However, the lifetime of each system is still, at best, an estimate. Treatment lifetime depends on the types of processes that provide the majority of the metal removal. Anaerobic systems (vertical flow systems) rely primarily on sulfate reducing bacteria, which reduce sulfate to sulfide and generate alkalinity. Metals can be precipitated as sulfides, and acidity is neutralized. These systems can remove over 90% of the metals and increase pH from around 4 to over 7. The bacteria will remain active as long as the system remains anaerobic and contains an adequate supply of sulfate and small chain organics. Although estimates of lifetime made on the total carbon in the system suggest that lifetime should exceed 20 years, data from field and laboratory studies show that the rate of sulfate reaction decreases with time, and that after several years rates decreased substantially. To maintain acceptable treatment, either additional organic material must be added or the total metal and acid load to the system would need to be reduced substantially. Aerobic systems (overland flow wetlands) can effectively remove metals from neutral mine drainage by reactions with organic material in the substrate. Over 90% of the copper and nickel have been removed in aerobic systems treating mine drainage in Minnesota. The primary removal processes in these systems include adsorption, ion exchange and complexation, which are finite; removal will cease unless new removal sites are generated. Two wetlands built in Minnesota have been successfully treating mine drainage for 12 years. At one of the wetlands, the annual production of new removal sites has been estimated to be equal to the annual metal input, and, as a result, metal removal should theoretically continue indefinitely.

Jan 1, 2005

The Coeur Rochester Mine is one of the largest and lowest cost primary silver mines in the United States. In January, the mine surpassed 3.1 kt (100 million oz) of historic silver production. Rochester is owned and operated by Coeur d’Alene Mines, the world’s largest primary silver producer. Rochester is the world’s seventh largest silver mine. It also produces gold — more than 31.1 t (1 million oz) in historic production. Cash operating costs have averaged 8 cents/g ($2.58/oz) of silver since operations began in 1986.

Jan 1, 2004

By W C. Cook, S J. Mathews, A H. Purvis

The Golden Cross Gold Mine is located at the head of the Waite kauri Ri ver, 8 km northwest of Waihi near the southern end of the Coromandel Range. The mine produces gold and silver from epithermal veins hosted by Miocene andesitic flows and pyroclastics of the Coromandel Group. Golden Cross is owned in joint venture by Coeur Gold NZ Ltd (80 per cent) and Viking Mining Company Ltd (20 per cent). Mining is by open pit and underground methods. Mineralisation in a near-surface sheeted/stockworked vein zone is mined from the open pit. The deeper Empire Vein System is mined from underground where higher grade mineralisation is restricted to generally discrete veins. The open pit stockwork zone is west of and offset from the updip trend of the Empire Vein System. The Empire (hangingwall) Vein strikes generally north-northeast and dips steeply west. Dips become subvertical at greater depth. The hangingwall vein is a well developed, generally continuous structure with relatively high gold grades. A complex footwall vein system forms shallow west-dipping offshoots to the hangingwall vein. Structure and gold grades become increasingly erratic away from the hangingwall vein. The better developed footwall veins carry economic grades and high 'spot' grades over 50 g/t Au are not uncommon. Highest gold grades are associated with tightly crustiform banded sections of quartz veins and with dark fine grained siliceous breccias. The main hangingwall vein occupies a major north-northeast trending fault structure, the Empire Fault. Footwall veining forms within subordinate splinter fault zones. There has been extensive multidirectional pre-, syn- and post-mineralisation faulting. Fault manifestation is highly dependent on host rock characteristics. The central part of the hangingwall vein and surrounding silicified country rock has been shattered by a major fault structure, the West Mine Fault, forming a poorly consolidated, blocky quartz-breccia ore zone. Away from the more brittle ore zones and associated silicified envelope, wide clay-filled shears mark the major fault trends. Development of the deposit is considered to have occurred in two distinct stages related to separate episodes of dilational jog movement on the Empire Fault. The first phase reactivated the pre-existing Empire Fault as a dilational fissure with subordinate splinters on the footwall side. The Empire Vein System (hangingwall and associated footwall veining) formed during this phase. A second phase of renewed movement with further dilation resulted in more extensive fracturing of the Empire Vein and surrounding country rock and formed the sheeted/stockwork veining of the open pit. An upwards/westward migration of the hydrothermal system is assumed but fluid pathways between underground and open pit veining are unclear. Ore extraction and mining geology methods have responded to improved understanding of the grade and structural variability, and changing ground conditions inherent in the vein system. The underground mine produces ore from flatback cut and fill, post-pillar and bench stopes. Open pit and underground ores are campaign milled through a conventional CIP plant.

Jan 1, 1993

By B. Anderson, P. Churak, S. Dewar, A. Johnson, P. Eger

Although vegetation can be successfully established on fine taconite tailings, innovative approaches are needed to reclaim the coarse tailings used for dam construction. Through a series of cooperative projects with various government agencies and industries, EVTAC has been able to develop a unique closure plan. This plan will not only meet current reclamation standards, but also provide mitigation for a disturbed wetland and possibly create a tree plantation in the interior of the basin. By using waste products and exchanging materials, reclamation of the entire basin will be accomplised in a cost effective manner.

Jan 1, 2002

Phelps Dodge Mining’s Bagdad, AZ copper facility uses a large series of cone crushers and ball mills to reduce copper ore to very fine particles. The solids are mixed with water to create a slurry. Milk of lime is added to this slurry to raise the pH. Small amounts of reagents are also added, including a frother to make bubbles, as well as a collector chemical that causes the copper minerals to stick to those bubbles. This material is pumped to a series of froth flotation cells to concentrate the copper. Air is blown into the flotation cell tank and the pulp mixture is vigorously agitated. Rising bubbles carry the copper particles over the edge of the flotation tank. The bubbles break after they flow over the edge.

Jan 1, 2005

By Y Xiao, C Lei, C Shu, W Wang, K Wang, J Deng

To investigate the effect on coal spontaneous combustion with high geo-temperature, an experimental apparatus was developed to measure characteristic parameters of two kinds of coal samples at different temperatures: one was 40°C (G coal sample) and the other was a rising temperature from room temperature (C coal sample). Based on the relationship between CO concentration and the temperature variation, a calculation model of the apparent activation energy of coal was established. The results indicated that the oxygen consumption rate, the generation rate of CO and CO2, and heat release intensity of G coal sample were higher than C coal sample. This trend was more and more obvious as the temperature increased. Furthermore, the apparent activation energy of G coal sample was lower than C coal sample, especially at low temperature stage, which demonstrated that the more the oxidation and exothermic reaction of G coal sample was enhanced, the less energy was required to break the barrier of oxidation reaction. Under the same condition, the speed of oxidation reaction was faster for the coal in the high geo-temperature environment, which was more liable to spontaneous combustion.CITATION:Lei, C, Deng, J, Xiao, Y, Shu, C, Wang, K and Wang, W, 2017. The effect of high geo-temperature environment on spontaneous combustion – an experimental study, in Proceedings Australian Mine Vent Conference 2017, pp 137–142 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By Andy Mille

The paper highlights development of tunneling methodology in the UK during the years 1990-2000 using the example of two major tunneling contracts where there solution of difficult tunneling problems during construction has benefited the industry as a whole. The paper deals with specific difficulties on two Contracts. The London Water Ring Main 80 kms (50 miles) long tunnel average internal diameter 2.54 m (9 ft4 in) and the Brighton Stormwater Tunnel 5.2 km (3.2 miles) long tunnel with an internal diameter of 6 m (19 ft 8 in). The results of human endeavour and technological innovations will demonstrate the giant strides made in tunneling methodology in the last decade of the 20th Century.

Jan 1, 2001

By M Passmore, N Poznik

Olympic Dam is a world-class deposit and is unquestionably one of the most geologically, structurally and texturally complex orebodies in the world. As development advances into the Southern Mine Area (SMA) the geological understanding is rapidly evolving as underground drill rigs are prioritised to provide the additional data necessary to convert Indicated and Inferred Resources into Measured Resources. The SMA represents approximately 70 per cent of Olympic Dam’s total resource and is significantly more complex when compared to the Northern Mine Area with respect to the diverse nature and origin of lithotypes, rock mass characteristics and the extent of major structures controlling primary mineralisation trends.Recent mine development into the central SMA has been impacted by a major structural gouge zone. Sound geological interpretation allowed mine geologists to successfully integrate their local understanding of the distribution of lithotypes with critical geotechnical data, chiefly rock quality designation (RQD), to delineate and better predict this major structural gouge zone. As a direct result, development rates improved whilst also increasing awareness for the importance of sound geological interpretation utilising all available data. In order to maximise predictability across all systems in place through the mining geology value chain, the integration of geological and geotechnical data in a geotechnical RQD block model provides an additional tool to assist in preventative solutions for complex problems to achieve a proactive mining environment.This paper details the methods used to build the RQD block model, the geostatistical estimation parameters, 3D geotechnical domain wireframes, challenges regarding legacy approaches, and collection of geotechnical information and incorporating/linking geotechnical data with geological features, including the use of grade and lithotype domains. Although the geotechnical block model proved difficult and complex to construct, the resultant product has seen successful integration of geological and geotechnical data into mine planning providing higher resolution of critical parameters for local mining areas.CITATION:Clark, J M, Passmore, M and Poznik, N, 2017. Olympic Dam rock quality designation model – an integrated approach, in Proceedings Tenth International Mining Geology Conference 2017, pp 27–36 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By H. J. Uananisa, M. J. Papo, C. W. Siyasiya, W. E. Stumpf

"SynopsisThe need to reduce weight while maintaining good mechanical properties in materials used in the automotive industry has over the years seen an increased exploitation of various steels to meet this new demand. In line with this development, the ferritic stainless steel family has seen a wide application in this industry, with the AISI 436 type increasingly being used for automotive trims and mufflers for exhaust systems, as well as a significant part of this steel’s application being for the manufacture of wheel nuts and wheel nut caps in trucks, mainly through the deep drawing process. However, there have been reports of some poor surface roughening of this material during deep drawing, with tearing and/or cracking also reported in some instances. This has been suspected to possibly be associated with some local differences in localized mechanical properties between grains and grain clusters of the rolled and annealed material.In order to investigate the poor surface roughness exhibited by AISI 436 ferritic stainless steel (FSS) during deep-drawing, Lankford values (R-mean and ?r), grain size, and microtextures of various sheet samples from this steel were studied. The chemical composition range for the samples was 0.013–0.017% C, 17–17.4% Cr, 0.9–1% Mo, and 0.4–0.5% Nb. The steels were subjected to various hot and cold rolling processing routes i.e. involving industrial direct rolling (DR) or intermediate annealing rolling (IR), and the drawability and final surface qualities of the steels were compared. It was found that the DR route gave an average R-mean and ?r value of 1.9 and -1.4 respectively, while the IR route yielded an average Rmean and ?r value of 1.6 and 0.52 respectively. The high ?r value for the DR processing route had a substantial adverse effect on the drawability. IR samples exhibited a smoother surface finish on visual inspection, while clear flow lines were visible on the DR samples, despite the fact that DR is the preferred industrial processing route due to the reduced production costs it offers. This observation was also confirmed through SEM examinations. The difference in the surface quality was attributed to microtexture. However, the mechanism responsible for this difference still needs to be identified."

Jan 1, 2015

By R. A. Meister

The study on improving surface coat refuse disposal site inspections included surface inspections of 15 refuse disposal sites. Monthly aerial photos were taken of the sites and computer methods were used to determine elevation changes. Photogrammetric techniques that were used are described in detail. A comparison of the results of each of these inspection techniques is included. A detailed evaluation of the photogrammetric techniques was made and conclusions were drawn concerning the advantages and disadvantages of using aerial photography and photogrammetry as part of the inspection procedure. Operators' opinions of the aerial photography methods are included.

Jan 1, 1980

By Fadeela Saloojee, Frank K. Crundwell

"Pressure leaching is an option for copper recovery from chalcopyrite. Leaching takes place at high temperatures and pressures in the presence of an oxidising agent. This work shows how the performance of pressure leaching circuits may be improved by optimising the configuration of autoclaves and the heat-removal method. The objective was achieved by creating an autoclave model by combining mass balances, energy balances and population balances. A base-case circuit consisting of a single autoclave was chosen, and this base case was compared with options for increasing capacity by adding more autoclaves to the circuit. These capacity–increase options include circuits in which the additional autoclave is added in parallel, in series and in series with thickening between the two autoclaves. The copper extraction, productivity and cooling requirements for these options are compared. The series circuit with inter-stage thickening has the highest extraction and productivity, however, the cooling duty in the first autoclave is high. In addition to comparing circuit options, three options for heat removal were investigated: cooling coils, quench water and flash recycling. The flash-recycle option results in the highest copper extraction, and the quench-water option gives the lowest copper extraction. INTRODUCTION Background Copper sulfide ores and concentrates containing chalcopyrite are typically hard to leach under atmospheric conditions. Smelting of these ores may also be a challenge, due to the inability of smelting processes to handle low-grade ores, as well as impurities such as arsenic and antimony. Alternative hydrometallurgical routes to treating chalcopyrite are therefore required. One option is pressure leaching, which is the focus of this work. In the pressure leaching process, sulfide ores and concentrates are leached in autoclaves at temperatures of 200 to 220°C and a pressure of about 3000 kPa (Schlesinger et al., 2011). An oxidising agent, usually oxygen, is required to oxidise sulfide ions to sulfate ions. The oxidation of sulfur to sulfate is exothermic; consequently, a method of heat removal is necessary in order to maintain the temperature in the autoclave."

Jan 1, 2015

By J R. Lang, J K. Mortensen

The Canadian Cordillera contains numerous classic porphyry deposits and several unusual subtypes, including the alkaline suite of porphyry Cu-Au deposits and the Tombstone magmatic suite and associated Au¦W deposits. The alkaline suite formed in collisional settings in island arcs whereas the Tombstone suite was emplaced in an active fold and thrust belt in a continental arc. In addition to different regional settings, these suites differ in the type of underlying basement, metallogeny, and the styles of mineralization. Both magmatic suites were emplaced over short intervals, probably in response to specific tectonic events. In the case of the alkaline suite, the tectonic event promoted magmatic processes suitable for the formation of porphyry Cu-Au deposits. The tectonic environment is less well constrained for the Tombstone suite, but the result was the formation of distinctive porphyry and intrusion-related Au¦W deposits.

Jan 1, 1995

By A. J. Thompson

The Metropolitan Transportation Authority (MTA) East Side Access project (ESA) will, when it is complete, provide a new link to the east side of Manhattan from Long Island, NY that, linked with the Second Ave. Subway currently under construction, will assist in relieving overcrowding at Penn Station as well as the Lexington Ave. subway. ESA will bring Long Island Railroad (LIRR) directly from Long Island into a new station located 37 m (120 ft) beneath the existing Grand Central Terminal (GCT) located in the heart of Manhattan. It will connect the LIRR?s mainline tracks in Queens, via the existing 63rd Street Tunnel under the East River, to a new terminal constructed within, and beneath, the historic Grand Central Terminal.

Jan 1, 2012

By Joe Zhou

"Mineralogical characterization and metallurgical extraction of silver is challenging due to its complex mineralogy and chemistry. Over 200 Ag-bearing minerals have been identified and a silver-rich ore body would typically contain 5 to 10 different silver minerals. Silver can occur not only as discrete microscopic (visible) silver minerals but also as submicroscopic (invisible) silver in other minerals. During processing, silver may form passivation compounds such as silver hydroxide, silver sulphide, jarosite-like silver sulphate, silver halide or silver cyanide precipitate, all of which may negatively impact on silver extraction. Knowing the deportment of silver in the ore and its metallurgical products is important in flowsheet design and plant optimization. This paper begins with the classification of silver ores and minerals and a review of processing techniques, and focuses on the major mineralogical factors to explain why and how these factors affect silver extraction. Case studies are provided to demonstrate the application of silver process mineralogy in flowsheet design and plant optimization.INTRODUCTIONSilver was known to and utilized by mankind since ancient time. Actually, it was one of the earliest metals discovered and utilized by mankind after gold and copper.Silver is the whitest metallic element. It is rare, strong, corrosion resistant, and unaffected by moisture, vegetable acids, or alkalis. Silver is also resonant, moldable, malleable, and possesses the highest thermal and electric conductivity of any substance. The chemical symbol for silver is Ag, from the Latin argentum, which means white and shining. Although silver does not react with many chemicals, it does react with sulfur, which is always present in air at trace amounts. The reaction causes silver to tarnish, and consequently it must be polished periodically to retain its luster.Silver possesses many special physical characteristics and qualities that make it useful to a variety of industries. The photography industry is the biggest user of silver compounds. Silver forms the most light-sensitive halide salts, which are essential to developing highquality photographic prints. Silver also has the highest electrical conductivity per unit volume of any metal, including copper, so it is used extensively in electronics."

Jan 1, 2010