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Northern Iron Ltd (NIL) is an Australian listed company that recently brought the historic Sydvaranger open pit Magnetite Mine (the Project) in Northern Norway successfully back into production. NIL made the decision to operate the Project on an owner mining basis, due to limited large scale mining expertise amongst Norwegian mining contractors, a long mine life, a limited range in planned mining rate and to minimise costs. As a new mine operator in a country where labour practices are strictly regulated, there was the desire to reduce the risk associated employing and managing skilled personnel. This was achieved by coupling the purchase of the required mining equipment from the original equipment manufacturer's (OEM) regional dealers with OEM supported Maintenance and Repair Contracts (MARC). This paper examines the process that was followed to implement an owner mining operation in a short time frame; approximately 12 months from the initial requests for quotation to actual delivery of mining equipment to site, and some of the challenges faced. By following a formal and well-tested process, not only was the implementation achieved in the set time frame, but significant value was added through the cost savings achieved in the equipment purchase price and MARC rates that were negotiated through this process.

May 1, 2010

By P D. "Takis" Katsabanis

The phenomenon of sympathetic detonations in blastholes is investigated by comparing experimental observations and numerical modelling results. Numerical modelling using the TDL computer code and Forest Fire decomposition rates for commercial explosives has shown the importance of blasthole diameter, impedance of the stemming and host rock. Comparison with experimental observations has also shown that sympathetic detonations cannot always be treated as shock to detonation transition. Examination of previous results which have been obtained from calibrated low amplitude shock experiments reveal that there is an ignition threshold prior to the detonation threshold. The difference between the two thresholds is more pronounced in the case of air bubble sensitized products. The ignition threshold can be very important under the confinement provided by the blasthole and the conditions of application. It also correlates well with the pressures expected at the gap distances of interest in the practical application. It is suggested that critical energies are used as the criterion for cross initiation in blastholes. Practical suggestions based on the numerical calculations and experiments based on these calculations are also given and discussed.

Jan 1, 1991

By James Westfield

I welcome this opportunity to appear before you and to review briefly the various health and safety services of the Bureau of Mines available to the mining industry, other than coal, and also to tell of our plans for extending these services to improve safety and health conditions. The Bureau's health and safety activities are basically services by which we attempt to develop and disseminate information on improved techniques in mine accident prevention and promote mine safety education in the mineral industries. Unfortunately, some mining companies, particularly some of the smaller operations, seem to be unfamiliar with these services, The Bureau of Mines is charged by law with the responsibility for inspecting coal mines; other services to the coal mining industry and are provided only on request, Safety inspections and other services that we offer are provided for noncoal mining industries solely upon request.

Jan 1, 1958

By C. McCall, J. T. Knight, J. R. Ridley

Gold mineralisation in the gabbro sills is mainly stratabound to quartz- and Fe-rich, granophyric-textured units and is sited in undeformed, brittle quartz vein sets, which form pipe-like orebodies. Hydrothermal wallrock alteration consists of hornblende-plagioclase-calcite-quartz with minor biotite, garnet and chlorite and with arsenopyrite and pyrrhotite as the dominant sulphides. Geothermobarometric data suggest that gold was deposited at around 520 degrees C at 2.8-3.8 bar. Mineralisation is thought to have occurred during amphibolite-facies metamorphism. Fluid inclusion and isotope data indicate that gold mineralisation was the result of deposition from a low-salinity H2O-CO2-CH4 fluid of either metamorphic or magmatic origin. Although the Three Mile Hill deposit differs from others in the area in its wallrock-alteration assemblages, peak-metamorphic timing of gold deposition and distinct geochemical associations it forms a brittle stratabound ore body which suggests structural and gold-depositional mechanisms in common with those of the other gabbro-hosted gold deposits

Jun 18, 1905

By W. Breytenbach

Traditionally, dithiocarbonates (xanthates) have been the preferred collectors for the flotation of platinum-bearing sulphides. However, collector development has led to trithiocarbonates (TTC), which have proven to be very effective bulk sulphide collectors. The interest in TTC flotation behaviour is currently focused on the interaction of these collectors with other collectors, specifically the dithicarbonates. Batch-flotation research has shown synergism to exist among dithiocarbonate, dithiophosphate and trithiocarbonate collectors. Increased sulphide recoveries, both for the first-minute and final concentrate, were realized using mixtures of these collectors relative to the standard.

Jan 1, 2003

By Oboso A, Nakahiro Y, Takenaka Y, Wakamatsu T

As part of the fundamental studies on the recovery of Au by solvent extraction, the synergism of combined extractants on the extraction of An from the sulphuric acid solution containing thiourea was investigated. Extractants tested were di-(2-ethylhexyl)phosphoric acid (D2EHPA), tri-n-octylamine (TOA), tri-n-butyl phosphate (TBP), and trioctyl phosphine oxide (TOPO). Four kinds of extractant combinations, D2EHPA/TBP, D2EHPA/TOPO, TOA/I'BP, and TOAITOPO, were tested to clarify the synergism on the extraction of Au in terms of various concentration ratios, diluents, the concentration of sulphuric acid, and the concentration of thiourea.

Jan 1, 1993

Various reagents are added to flotation pulps to manipulate the chemical environment in order to create favourable conditions for the separation of the desired mineral from the unwanted gangue. Interactions occur between these reagents and between the other chemical parameters existing in the flotation pulp which complicate the elucidation of the behaviour of the respective reagents. This paper discusses the roles of the main classes of reagents added viz. collectors, frothers, depressants and activators, as well as the interactions between frothers and collectors. A case study reporting synergistic interactions between thiol collectors in the flotation of pyrite at pH = 4 is included. The use of Potassium n-butyl xanthate (PNBX) and a dithiocarbamate type collector (DTC) were tested both as pure collectors and as components in a collector mixture. In the batch flotation tests sulphur recovery and grade, water recovery, rate of recovery and image analysis of the surface froth were used to evaluate the effect of the mixture on the overall flotation performance. Bubble loading tests showed that the use of the mixture improved the efficiency of the particle collection process by bubbles. Thermochemical measurements of the adsorption of the collectors onto the mineral, indicated the formation of different surface products by the two collectors.

Jan 1, 1998

By Pierre De Pasquale, Aquilino Antonio Alvarez-Castro

Greenhouse gas emissions are now an essential issue for extractive industries. Actually, lowering of quarry energy consumption and CO2 emissions participates to answer both environmental and financial issues. The “EE-Quarry” European project, supported by the European Commission (EE stands for Energy Efficient), develops a new and highly effective modelling and monitoring Energy Management System technique to improve Energy Efficiency and move to a low CO2 emission rate in the nonmetallic mineral industry.

Jan 1, 2016

By Brian W. Stump, David P. Anderson, John Wiegand

Mining explosions are designed for a variety of purposes including the fragmentation and movement of materials. The blast design is dependent on the particular application intended and the material properties of the rock. The range of mining applications from hard rock quarrying to coal exposure to mineral recovery leads to a great variety of blasting practices.

Jan 1, 1997

By Rashmi Ramesh

Zinc oxide nanoparticles and nanostructures form an active area of research in the recent years. It can be doped to modify electronic, optical and other properties. Synthesis and characterization of zinc oxide is of extreme importance in order to understand the structure property relationship in this material which is now being considered of importance next to carbon nanotubes. Microstructure of zinc oxide nanomaterial is extremely sensitive to the preparation conditions. Nanocrystalline pure and Mn and Mg doped zinc oxide samples were prepared by wet-chemical method under different growth conditions. The samples were investigated for crystalline phase, microstructure, morphology and luminescence characteristics. The effect of Mn and Mg doping on the characteristics of ZnO have been discussed.

Jan 1, 2010

By Selda Ozkan

In this study, a combination of cathodic arc physical vapor deposition (PVD) and molten salt electrolysis methods were used to obtain ZrB2 layers on AISI 304 grade stainless steel surface. Prior to boriding, steel surface was coated with metallic zirconium via cathodic arc PVD method and then the zirconium coated steel was borided by molten salt electrolysis. Well adherent, dense, ZrB2 layers are formed on the substrates. The thickness of the ZrB2 layer showed dependence on the thickness of the metallic Zr coating layer and the time of boriding. During the boriding process the alloying elements of the substrate also took part in the coating structure depending on their diffusion characteristics.

Jan 1, 2010

By Sutham Niyomwas

Keywords: Al2O3-SiCW, Ceramic Matrix Composite, Carbothermal Reduction, Kaolin The formations of Al2O3-SiCw composite have been obtained in situ by carbothermal reduction of a mixture of kaolin and activated carbon. The reaction temperature was controlled at between 1400°C to 1600°C. The synthesized products were mixtures of alumina and silicon carbide in the form of whiskers. The effects of milling time of precursors and reaction temperature are presented. XRD and SEM analyses indicate complete reaction of precursors to yield Al2O3-SiC as product powders, with the SiC having porous and whisker morphology.

Jan 1, 2005

By M. Radwan, S. Shimada, S. Z. El-Tawil, K. A. El-Barawy, Y. Miyamoto

This study presents the results of synthesizing monolithic siliconoxynitride, Si2N2O, ceramic from a mixture composed of reclaimed silicon and natural desert sand by using the nitriding combustion synthesis method. Single-phase Si2N2O powder was prepared by the combustion of a mixture composed of silicon and pulverized sand in 3 MPa nitrogen gas. The combustion reaction completed in 2 min and the combustion temperature reached 1577°C.The as-synthesized Si2N2O powder is agglomerate of fine particles with sizes < 5 µm and has various morphologies; rod-like and irregular crystals, irregular kinking, hollow crystals and grown pseudo-hexagonal prismatic crystals. Porous Si2N2O compacts (24.5–47.1% porosities) were fabricated from the synthesized Si2N2O powder at different calcia-alumina additives (5–20 wt%) by normal sintering at 1500°C for 1 hr in N2atmosphere.They showed superior oxidation-resistance at high temperatures up to 1500°C in an oxidizing atmosphere of Ar/O2/H2O(70/20/10 kPa).Near-full dense Si2N2O compacts were also successfully fabricated from the synthesized Si2N2O powder with 5 wt% oxide additives by using the spark plasma sintering at 1600°C.DenseSi2N2O had good mechanical properties (18.7 GPa Vickers hardness, 3.3 MPa.m1/2fracture toughness and 363 MPa strength) and excellent chemical and oxidation resistance.

Jan 1, 2004

By Taegong Ryu

Nanosized tungsten powder was synthesized by the hydrogen reduction of ammonium paratungstate (APT) in thermal plasma. The effects of operating conditions on the product composition and particle size were investigated. The particle size of synthesized W powder was less than 30 nm in all cases tested. The sintering behavior of the synthesized powder (25 nm average size) was then investigated and compared with those of commercial W powder of 500 nm average size and W powder of 23 nm average size produced by milling the commercial powder. The sintering was done at 1400oC with various holding times. The hardness of the resulting compact from the synthesized W powder (315 VHN) was similar to that from the milled W powder (309 VHN), but the plasma-synthesized powder had a much lower tendency to form cracks. The compacts of both nanopowders were significantly harder than that of the commercial powder (192 VHN).

Jan 1, 2009

By Rolf Birger Pedersen, Alden Ross Denny

"Synthetic Aperature Sonar (SAS) is a powerful tool for ultra-high resolution marine survey. The Kongsberg HiSAS system deployed on the HUGIN AUV has a rangeindependent resolution of 3x3 cm for sonar image and ~10x10cm for the interferometric bathymetry product [1]. This resolution is achievable for areas up to 50 km2 on a single survey mission providing huge multi-attribute datasets. This technology, originally designed for military and oil-industry applications, has the potential to revolutionize scientific seafloor mapping. The extreme resolution of this technique allows for deposit mapping in and around seafloor hydrothermal systems, including the discovery of extinct venting structures. By clearly distinguishing between volcanic and hydrothermal landscapes based on features below the resolution of conventional multibeam systems, SAS enables an entirely new level of hydrothermal deposit survey. Additionally due to the extreme resolution of this survey technology, repeat survey and change detection should allow centimeter-scale changes in deposit morphology to be routinely detected over an entire hydrothermally venting region. In collaboration with the EU funded MIDAS project, the Centre for Geobiology at the University of Bergen will deploy the HUGIN AUV this summer at two distinct shallow venting systems on the Arctic Mid-Ocean Ridge system. The AUV will collect repeat bathymetry at the Jan Mayen Vent Field, and extend the SAS coverage to include newly discovered venting sites. We will present the preliminary findings of this expedition, including the first deposit estimations made from full-resolution SAS mosaics."

Sep 1, 2014

By Samuel Frimpong

Synthetic fuel is a liquid hydrocarbon fuel synthesized from unconventional resources, such as tar sands, heavy oil, coal, and oil shale. These unconventional resources are immense and will be a major energy source for the 21st Century as the availability of conventional crude oil and natural gas declines. The authors review the available global distributions, production data, research frontiers, and current research organizations involved in tar sands, heavy oil, coal, and oil shale. Tar sands and heavy oil is mainly deposited in Canada, Venezuela, and the United States. Oil shale reserves are found in United States, Jordan, China and Australia. Coal occurs in United States, Russia, China, Canada, and Australia. Major research and development efforts are focused on reserves identification, transportation technologies, production cost modeling, bitumen extraction process improvements, coal liquefaction technologies, elimination of pollutants, greenhouse gases, and safeguarding human health and the environment. This review forms a major source for educating the public about these important energy sources, and the need to develop environmentally sound technologies and policies for their extraction.

May 1, 2007

By Jian Wu

In this paper, the surrounding rocks and the supports in a longwall are taken as an integral, i.e. a system. The structural characteristics and behavior of the system are discussed based on in-situ observations. A set of equations, which describe the interaction among the support, immediate roof and main roof, are developed. These equations can be used to design the longwall powered supports more reasonably and economically.

Jan 1, 1989

By H. A. D. Kirsten

Shotcrete has become a strategic component of support in underground mines. The ductility of reinforced shotcrete makes it a safe and economic means of surface support under adverse static and dynamic loads. The ability of ductile shotcrete to sustain load at large deflections enables excavations in squeezing conditions to be stabilized and the safety in excavations subject to rock bursting, to be assured. A Shotcrete Working Group was formed to find the configurations of fibre reinforcement that would give shotcrete the same ductility as when reinforced with mesh. Beams and panels reinforced with various types and lengths of fibre were accordingly tested. A single mix design consisting of river sand, ordinary Portland cement, fly ash, condensed silica fume and gunite dust and segregation suppressant was used. Steel and polypropylene fibre varying in length from 25 to 50 mm were used in nominal contents of 5 % and 0.5% by mass respectively. Beams, panels and control specimens were shot into specially made formers. Suitable mixing procedures were developed for the different types of fibre. The test specimens were shot in a semi-dry mix process. The shotcrete was cured until tested 28 days after shooting. The fibre contents and uniaxial compressive and Brazilian tensile strengths of the shotcrete were determined from the control specimens. The beams and panels were tested in bending in specially manufactured test rigs. The beams were examined for simple supports and fixed ends. The panels were fixed in a manner that simulated underground conditions and were loaded statically under uniform pressure. The beams were loaded and the corresponding deflections measured up to failure. The panels were loaded up to mid-span deflections of 150 mm. The results are presented in the form of load-deflection graphs. The peak loads and ultimate deflections for the fixed end beams were considerably larger than for the simply supported beams for the various types of fibre considered. None of the beams tested, however, were able to sustain load at relatively constant value beyond the peak load. The panel tests showed that 40 mm and 50 mm long steel fibre and 30 mm, 40 mm and 50 mm long monofilament polypropylene fibre reinforcement gave shotcrete the same ductility as mesh.

Jan 1, 1998

By P. J. Sylvester, D. H. C. Wilton, R. I. Wheeler, M. A. E. Huminicki, D. Evans-Lamswood

"Systematic characterization of the mineralogy of massive sulfide ore deposits can provide valuable insights into ore genesis and metallurgical processing that would not be apparent otherwise. We describe a method wherein (1) normative mineral abundances are calculated from whole-rock chemical assays using an algorithm, (2) the results are cast in block models, (3) the results are then verified with automated image analysis of a subset of samples prepared as grain mounts by backscattered electron imaging and X-ray mapping on a scanning electron microscope, and (4) those verified results are integrated with textural data determined by optical microscopy.The technique is applied to the magmatic Ni-Cu-Co sulfides of the Ovoid orebody, based on geochemical assays of 3175 whole-rock samples. Three principal ore zones are defined in the Ovoid. Type I ore occurs in the center of the deposit; it is magnetite-rich and pyrrhotite-poor with intermediate contents of pentlandite and chalcopyrite. Type II ore surrounds Type I ore and is pentlanditechalcopyrite- rich with intermediate contents of pyrrhotite and magnetite. Type III ore occurs at the base and along the outer periphery of the northern part of the orebody; it is pyrrhotite-rich and chalcopyrite- poor with an intermediate content of pentlandite, and a low-to-intermediate content of magnetite. La caractérisation systématique de la minéralogie des gîtes de sulfures massifs peut fournir des indications précieuses sur la genèse des minerais et le traitement métallurgique qui ne seraient pas disponibles par d’autres méthodes. Nous décrivons un procédé par lequel (1) un algorithme est utilisé pour calculer l’abondance de minéraux normatifs à partir d’analyses lithogéochimiques, (2) les résultats sont exprimés dans des blocs diagrammes, (3) les résultats sont par la suite validés par analyse d’image automatisée sur un microscope électronique à balayage en électrons rétrodiffusés et par cartographie en rayons X sur des échantillons constitués de grains montés en résine, et (4) les résultats de cette validation sont combinés aux données texturales obtenues par microscopie optique.Cette technique est appliquée aux sulfures magmatiques de Ni-Cu-Co du gisement Ovoïde, en utilisant les analyses géochimiques de 3175 échantillons de roche totale. L’Ovoïde comprend trois types de minerai. Le type I est situé au centre du gisement; il est riche en magnétite et pauvre en pyrrhotite avec des quantités intermédiaires de pentlandite et de chalcopyrite. Le minerai de type II entoure le minerai de type I et est riche en pentlandite et en chalcopyrite avec des quantités intermédiaires de pyrrhotite et de magnétite. Le minerai de type III se trouve à la base ainsi qu’à bordure externe de la partie nord du gisement; il est riche en pyrrhotite et pauvre en chalcopyrite, avec un contenu intermédiaire en pentlandite et une quantité faible à moyenne de magnétite."

Jan 1, 2012

By Frank Haehnig, Kjell-Åke Averstad, Johannes Glückert

"AbstractThe Söderströmstunneln is part of the Citybanan project that is currently under construction in the centre of Stockholm. Main part of the lot Söderströmstunneln is a 300m long immersed tunnel connecting the inner-city islands Södermalm and Riddarholmen. It consists of three tunnel elements that have been immersed in summer 2013. Since the solid bedrock is descending in that area to more then 40m depth, the tunnel elements have been placed and are permanently supported on four pile groups that have been constructed in advance. The common Swedish system of steel core piles has been used to built the pile groups. Drilling and installation of the steel cores piles in free water depth of up to 20m had to be done from a pontoon. The steel core piles are connected with underwater concrete pile caps.IntroductionCitybanan is a new 6km long double track railway tunnel running beneath central Stockholm including two new underground stations Odenplan and Stockholm City. When completed in 2017 commuter trains will have their own tracks through Stockholm, whereas the remaining railway traffic will continue to use the exisiting two tracks (see Fig. 1). This will double the capacity of the railway traffic through Stockholm. The Swedish transport administration Trafikverket is the client for this project. The design and built contract is carried out by the German contractor Züblin Spezialtiefbau GmbH together with their Swedish subsidiary Züblin Scandinavia AS.As the new Citybanan tunnel is in large parts situated below the bedrock level, it can be executed as rocktunnel in the common drill and blast method. Between the two inner-city islands Södermalm and Riddarholmen the tunnel is crossing the Söderström, an arm of the lake Mälaren. Here the bedrock is descending to a deep valley with more then 40m depth. To connect the rock tunnels between these islands a 300m long immersed concrete tunnel supported on pile foundations is currently under construction."

Jan 1, 2014