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By A. Bois-Brochu, G. Morin, G. Marin, M. C. Parr, J. Carignan

The presence of an alpha case on titanium parts produced by investment casting is problematic and has to be eliminated. The traditional techniques for the evaluation of its thickness are metallographic measurements and micro-hardness profiles. To obtain a better understanding of how the alpha case is formed with the underlying objective of limiting its depth, the present study proposes to characterize the microstructure and the chemical composition of the alpha case. Electron microprobe analyzer (EMPA) linescans were used to quantify the oxygen and substitutional elements that come from the mould and promote the alpha case formation. The chemical profiles were correlated with metallographic and microhardness measurements. For microstructure, optical microscopy (etched and polarized light analysis) was used. For phase analysis, samples were mechanically polished step by step and analysed using X-ray diffraction and optical microscopy. Furthermore, surface analysis techniques such as XPS and Auger Microscopy were evaluated but results were found to be inconclusive because the formation of the oxide layer was faster than its ablation and the matrix could thus not be analysed. The alpha case was observed on a Ti-6Al-4V step block casting.

Jan 1, 2014

By George J. Simandl, Suzanne Paradis, Kirk D. Hancock, Jana Simandl

Traditional prospecting and boulder tracing are the two most important field techniques used in exploration for magnesite deposits hosted by sedimentary rocks. Consequently, success depends largely on the prospector's ability to identify magnesite. A density agent called sodium polytungstate (3Na2W04·9WOj'HPJ was successfully used to determine the presence of magnesite in sedimentary carbonate rocks of southeastern British Columbia. A rapid field method was developed and tested. This method permits discrimination between limy dolomites, dolomites, magnesite-bearing dolomites and magnesite-rich rocks.

Jan 1, 1993

By Y. Kocaefe, D. Kocaefe, G. Ergin

Filtration efficiency depends strongly on the wetting of the bed media by aluminum. This project was undertaken to study the wettability of different types of bed media (tabular alumina) using sessile-drop and infiltration techniques. The samples were analyzed using optical microscopy, SEM, and TEM to study the chemical interactions. The results indicate the spinel formation at the interface. This paper presents some of the findings which compares the two methods and gives the results of the analyses on the wetting of alumina by aluminum.

Jan 1, 2004

By Masaharu Moteki

At present, the Unmanned Construction System (UCS) is adapted on initial operation against the disaster. For instance, it has been used in Unzen. When the scale of the disaster is big, or the danger to a person is big, the UCS is expected as a quick and safe construction technology. The Remote Controlled UCS is introduced into construction site to repair earth-fill embankment or to remove rock, as urgent measures after the disaster outbreak. For improvement of the operability, shortening of the skill time, reduction of the fatigue, examination of the most suitable system (placement of a monitor and the joy stick) of the remote system is a main theme in the Public Works Research Institute (PWRI). In the report of this year, when the operator controls construction machine directly or he controls it using remote system (he can check the situation of site only via monitor), the degree of achievement, construction efficiency and construction precision were inspected. The remote system which is based on the system used at Unzen was developed at PWRI.

Aug 1, 2013

By I Wilkomirsky, F. Parada, R. Parra, E. Balladares

"The neutral roasting of As bearing copper concentrates is confirmed well established and promising option for the treatment of this type of complex concentrate. The AS elimination by volatilization allows subsequent treatment of the calcines produced in a conventional pyrometallurgical process, by blending this product with standard concentrates.Several tests were performed using the fluidized bed pilot plant at the University of Concepción with different types of concentrates. Calcines, fines from two hot cyclones and flue dust from the ESP were collected. These materials were characterized using QEMSCAN® and the results used for the development of a mass and energy balance which took into consideration the specific chemical transformations that occurred in the reactor.A physico-chemical/kinetic model is proposed to explain the formation of bornite, chalcopyrite and magnetite. The mechanism involves solid-gas reactions between chalcocite, pyrrhotite and gaseous sulfur that without the mineralogical characterization would not have been possible to propose"

Jan 1, 2014

By M. Walmsley, D. Maynard

"This paper describes the use of terrain and soil information in the planning of mine developments, particularly in satisfying many of the existing provincial regulatory requirements. It is also noted that, if properly used, this will provide a solid data base for cost-efficient and environmentally acceptable land use.IntroductionIn planning the development or expansion of a new or existing mine, engineering alternatives are judged on many factors, one of which is the environmental influence. Ecological investigations, ensuring consideration of a rational approach to managing land use and environmental impacts, should be carried out prior to a final decision being made on mine development. The Pit Slope Manual (CANMET, 1976) suggests that both baseline aquatic and terrestrial data be collected and interpreted in such pre-mining surveys. In British Columbia, planning procedures now exist which incorporate biophysical studies to help identify, assess and manage major environmental impacts associated with mine development.Methods outlined in the Guidelines for Coal Development (E.L.U.C., 1976) have been successfully applied in recent years. Following this example, the Inspection and Engineering Division of the B.C. Mineral Resources Branch prepared guidelines to help expedite the development of new base metal mines (Procedures for Obtaining Approval for Metal Mine Development; Ministry of Energy, Mines and PetroleumResources, 1979).The metal-mine guidelines require the proponent of a new mine development project to prepare a two-stage assessment proposal which systematically moves from a preliminary feasibility study (Stage I) to a final project design (Stage II), including application for regulatory approvals. One purpose of the Stage I report is to provide a description of the existing environmental conditions that could be affected by the proposed development. A preliminary environmental impact assessment should also be reported. The Stage II report will contain detailed assessment and management of environmental impacts."

Jan 1, 1981

By G. Tozsin

A six-stage sequential leaching procedure was used to assess the leachability of heavy metals from waste rock in Antamina Mine. Sequential extractions procedure is well established for fine and small (? 1g) samples. However procedures for coarse and large test samples are lacking. This study presents results of the sequential leaches tests conducted on relatively coarse and large representative samples in terms of the availability and mobility of metals. Selective chemical reagents were used to extract metals from six different fractions where metals released with each subsequent extraction are believed to be bound tighter than those released in prior steps and therefore less likely to be leached.

Aug 1, 2013

By T. Newton, G. A. Bezuidenhout, P. J. Tauetsile, F. Trask

The technology to selectively leach gold, silver and base metals from ores, concentrates, and wastes, using an alkaline glycine solution, has initiated significant interest in using the new technology in various environments such as in-situ, in-place, dump, heap, and vat and agitated tank leaching. It has been shown that glycine acts synergistically with a number of other lixiviants to lower the net consumption of the other lixiviants while allowing low cost glycine solution recovery. Glycine is a non-toxic, stable, environmentally benign reagent that is available in bulk industrial quantities. It has the ability to dissolve most copper oxide and sulfide minerals, as well as native copper, whilst not interacting with acid consuming gangue nor dissolving iron and various or ubiquitous gangue elements. It acts synergistically with small amounts of cyanide to leach gold-copper ores at leach rates higher than either glycine or cyanide on their own, while significantly reducing cyanide consumption and eliminating detoxification requirements. The leaching behaviour of various glycine based systems will be reviewed, followed by the evaluation of the adsorption of gold onto activated carbon. Where the economics merit it, copper can be easily recovered using solvent extraction or sulfide precipitation.

Jan 1, 2017

By B. Zhu, W. E. Lee, N. Li

Al powder is used extensively as an antioxidant in carbon-containing bricks, but it cannot be used directly in water-based carbon-containing castables due to its hydration tendency. To overcome this problem, in this work, SiO2-PVA (polyvinyl alcohol) inorganic-organic hybrid coatings have been prepared via sol-gel processing, and used to coat Al powder. The hydration behaviour of uncoated and coated Al powders has been investigated in water at 60 or 100°C for 36h by examining phase and microstructural changes. While significant hydration is detected in uncoated Al powder, no obvious hydration is detected in coated Al powder, indicating that its hydration resistance has been greatly improved. Oxidation resistance of graphite coexisting with uncoated or coated Al powder was also investigated in air at 1250°C for 1.5h. The oxidation ratio of graphite coexisting with coated Al powder was similar to that of graphite coexisting with uncoated Al powder, indicating that both powders showed similar antioxidising behaviour. This, along with the much improved hydration resistance, makes the coated Al powder a potential antioxidant in carbon-containing castables systems.

Jan 1, 2004

By Serena Biella

Gold has received a growing interest as a catalyst for the selective oxidation of organic molecules using oxygen under mild conditions1. In the liquid phase application small gold particles (2.5-7 nm) deposited over different solid supports can be used but, like many other noble metals, their catalytic activity depends upon the nature of the support and the preparation metod2-5. In particular, gold on carbon is the preferred catalyst for the oxidation of the alcoholic 2-7 and the aldehydic7-9 groups and one of the best preparation method is the immobilisation of colloidal particles2-5,8,9. Suggested application of gold catalysis in fine chemicals production, tested on laboratory scale preparations, is reported in table 110. In order to produce more efficient catalysts for the liquid phase oxidation and to derive new insights into the reaction mechanism, we have made a comparison among catalytic systems based on different metals. The first effort was to test the activity, if present, of naked metal particles and then to study the influence of various materials commonly used as a support.

Oct 1, 2003

By F. Duan, J. Pfarr, J. M. Goris

"The U.S. Bureau of Mines, in cooperation with the Homestake Mining Co. and the University of Utah, is conducting a field demonstration to evaluate the behaviour of rock masses supported with cable bolts. One of two rock masses being studied is supported with both conventional and birdcage cables. This rock mass is located between the 6500 and 6650 levels of the 45-48N stope, 21 ledge. The second rock mass is the hanging wall of the D-limb stope between the 3500 and 3650 levels near the Ross Shaft and is supported with conventional cables. The primary objectives of the project are to monitor the behaviour of the two rock masses during mining using extensometers and cable support strain gauges, after which the rock will be modelled using the finite-element code UTAH III. Field data will be used to verify the modelling. In addition, a comparison between the effectiveness of conventional and birdcage cables will be made.45-48N StopeThe 45-48N stope is located in the 21 ledge between the 6500 and 6650 levels and contains about 233 000 short tons of mineable ore. The orebody lies within the Homestake Formation and is very irregular being approximately 200 ft long and 75 ft wide. Between the 6500 and 6650 levels, it dips from 35 degrees to 60 degrees east with a near-vertical plunge to the south. Mineralization is characterized by arsenopyrite and pyrrhotite with minor gold. The contact between the Homestake and the overlying Ellison Formation creates a plane of weakness along localized graphitic layers. The footwall dips at approximately 60 degrees but between 100 ft and 120 ft above the 6650 level , the hanging wall flattens to almost 20 degrees causing a significant mining problem."

Jan 1, 1991

By Roger D. Plouffe

In today's mining industry, it is possible to retrieve, from small-diameter holes, geophysical data for qualitative interpretation in exploration and quantitative interpretation in the development of orebodies. The primary objectives in the exploration stage are to identify where, within a hole, economic minerals are, and to help in lithological interpretations. Other aspects, which are more quantitative, are the interpretation of downhole logs for parameters which can be used in surface geophysical methods (i.e. density for gravity surveys, acoustic velocities for seismic surveys, and magnetic susceptibility for airborne and ground magnetic surveys). Recent advances in equipment design, portability and durability have made downhole logging in exploration more inexpensive and reliable. This new equipment is being used to generate very precise quantitative results. This is especially true on uranium development projects. The interpretation of gamma logs for eUJOS values has finally become precise enough that they have begun to replace chemical values in reserve calculations. Another part of development data is density and equilibrium information, which, with today's technology, is being derived from downhole probing. In the years to come, the trends for many metals are toward neutron activation techniques, or "in-situ assaying", and the use of multiple logs for better lithological and physical rock property determinations.

Jan 1, 1981

By Aalbert Zwijnenburg

One of problems connected with the use of gold/titania-based catalyst systems is the low yield in propene oxide (up to 2 wt %). It is shown that the low propene oxide yield is due to product inhibition. New options for propene epoxidation with hydrogen and oxygen are discussed. INTRODUCTION The direct gas-phase synthesis of propene oxide (PO), by the use of molecular oxygen, is still aimed for. Agbased catalysis is in principle possible, but selectivity at present is not promising. Highly dispersed gold on titanium containing catalysts show an extraordinary selectivity in the oxidation of propene to the corresponding epoxide (> 99 %), using a combination of H2 and O2 as oxidation mixture [1]. Additional studies of the epoxidation reaction have indicated several drawbacks of the Au/TiO2 catalyst. Firstly, the low conversion (1- 2 %) obtained under typical reaction conditions (atmospheric pressure, 323 - 423 K) cannot be increased by increasing the reaction temperature, because this leads to extensive by-product formation. Secondly, the low efficiency of hydrogen (relatively large amounts of water are formed) is hard to prevent. Finally, significant deactivation of Au/TiO2 catalysts within several hours on stream has been observed. Deactivation can be almost completely prevented by using dispersed TiO2 supports, such as TiO2/SiO2 and Titanium-Silicalite-1 (TS-1) [2]. In recent literature [2,3] a hydroperoxide-like intermediate has been proposed to be responsible for the selective epoxidation. This oxidising species is said to be formed over gold and subsequently used for epoxidation over the Ti-containing support. The support is responsible for the slow desorption of PO. One of the problems for future industrial application might be the low yield in propene oxide. Furthermore, the presence of minor amounts of by-products, not detected on lab-scale catalyst testing, might complicate the separation unit in an industrial process. The reason for the low PO yield over Au/TiO2-based catalysts will be discussed in this paper. Temperature Programmed Desorption (TPD) and micro-flow experiments have been carried out to study PO desorption and catalyst performance, respectively. A catalytic cycle is proposed together with its consequences for the maximum yield in PO. Finally, several process and catalyst options are discussed in view of potential future industrial application.

Oct 1, 2003

By J. Gustavsson, S. Holmin, Å. Afvander, E. Rosseland, E. Zimmerman

There are numerous advantages in replacing lead-based anodes with mixed metal oxide (MMO) coated anodes in copper electrowinning; for example, lower energy consumption, improved working conditions for operators and less environmental impact. Since 2012, Permascand AB in Ljungaverk, Sweden has evaluated Permascand coated titanium anodes in copper electrowinning pilot trials at Glencore Nikkelverk in Kristiansand, Norway. The investigation has proceeded in three different steps (Phase I, II and III). In Phase I, different Permascand coatings, electrode structures and coating methods were investigated. The results showed that improved current distribution, lower energy consumption and longer service life could be obtained with expanded mesh electrode structure in a box configuration compared to rod anodes in a single-mode construction. In addition, improved current distribution and less coating wear was found when electrostatic spray coating was used instead of brush (manual) coating. It was also found that the extrapolated service life from controlled lab experiments at 200 A/m2 was much shorter compared to what was experimentally obtained in copper electrowinning pilot trials at similar current densities. This was mainly attributed to different coating failure mechanisms in lab and industrial copper production. INTRODUCTION Traditionally lead-based anodes have been used in copper in electrowinning due to lower cost. But there are many advantages in replacing lead-based anodes with mixed metal oxide (MMO) coated titanium anodes in copper electrowinning, such as lower energy consumption, higher corrosion resistance, improved working conditions for operators and less environmental impact. Still, many facilities are using lead-based anodes, although the progression of using metal oxide coated anodes in copper electrowinning has slightly increased (Robinson et al., 2012).

Jan 1, 2019

By T. A. Postolski, A. J. Sinclair

"Abstract- Two examples are used to describe how geological features impact on the development of semi-variogram models to be used for geostatistical resource/reserve estimation of porphyry-type deposits. In the Main zone of the Huckleberry porphyry copper deposit, mineralization is concentrated in fracture zones localized in volcanic rocks, along the eastern and southern margins of a granitic stock. Mineralized volcanic rocks can be subdivided into three separate domains, each with its own preferred direction of mineralization that is reflected in contoured Cu diagrams and semivariograms.The East zone at Huckleberry deposit, spatially distinct from the Main zone, is controlled by a fracture zone elongate roughly east-westerly and bounded on the south by a major fault (easterly striking and steeply dipping) across which there is a dramatic drop in grades. The eastern part of the East zone appears to be coaxial with a large intrusive body; the western part contains a small, elongate dike-like intrusion. Contoured Cu values for many levels suggest that the principal direction of geological elongation of the east and west domains of the East zone differs significantly. Independently derived semi-variogram models for each domain are different and reflect this difference in trend.In both Main and East zones of the Huckleberry deposit, block estimates by ordinary kriging are significantly different using a domain-specific semi-variogram model than using a deposit-general semi-variogram model. The domain-specific estimates are deemed better because they are based on local controls of mineralization and have less conditional bias than those generated by the depositgeneral semi-variogram model."

Jan 1, 1998

By P. E. Auger, J. E. Gill

"The zinc deposits to be described are in Lemieux township a few miles south of the Tabletop mountains, in the central part of Gaspe peninsula, Quebec. Although they have not been worked, they constitute a potential source of zinc and lead and structurally are of considerable interest.GENERAL CHARACTER OF THE OCCURRENCEThe deposits are in sharp-walled quartz-carbonate veins and breccia zones carrying locally, and in varying amounts, sphalerite, galena, pyrite, marcasite, chalcopyrite, and specularite. Those so far investigated strike generally north-south, have steep dips, and cut through sediments of Lower Devonian age, mostly calcareous argillites or siltstones. Wall-rock alteration is negligible.BROADER STRUCTURAL FEATURESThe principal known occurrences are in the south-central part of a dome structure measuring 6 by 5 miles. The argillaceous sediments are overlain, on the flanks of the dome, by sandstones and lavas. These have been stripped from the central part of the dome, revealing the veins in the argillites beneath. The veins formed after the volcanics, but the fractures and breccia zones in which the deposits formed are confined mainly to the argillite series, presumably because of the greater strength of the lavas.The argillite series is cut by dykes, sills, and small stocks of diorite and acidic 'porphyries' that are older than the veins.THE FEDERAL HILL AREAThe distribution of known veins is shown in Fig. 1. The characteristic features of the veins are well illustrated by the Federal Hill area shown in Figs. 2, 3, and 4, and described below."

Jan 1, 1954

By Bern Klein, A. Tugba Cebeci, Libin Tong

"Sensor based sorting faces two main challenges related to limited capacity/throughput and the ability of sensors to accurately discriminate based on estimated grades. This paper is aimed at improving sensor discrimination. Sensors have the ability to measure more than a single response. X-ray fluorescence (XRF) can detect and provide concentration information about a range of elements. Similarly, electromagnetic sensors (EMs) can generate magnetic susceptibility and conductivity responses over a range of frequency levels. The sensors thereby provide a response signature rather than a simply a single response that is a proxy for a metal grade. Furthermore, integrating sensor responses can improve the discrimination of metal bearing rock from waste. A study was conducted on a gold ore to assess sortability using XRF and EM sensors. A multi-variable regression approach was used to develop models that included a range of responses. Correlations improved significantly when compared to single response correlations. The approach showed that both positive and negative correlations contributed to the improved correlations. Stepwise regression simplified the models and showed that 2nd order interaction effects can be important. The approach also showed that combining different responses can improve discrimination accuracy. An important outcome of the study was that an ore that had been consider not to be sortable was determined to be sortable through the application of an approach that used the sensor responses in a more intelligent manner.INTRODUCTIONMining is aimed at recovering valuable minerals from their host rocks. Many methods are used to recover valuable minerals, and finding efficient and cost-effective ways is the key in research and production. . Ore sorting technology is fitting this definition. It not only discards waste rocks away from the concentrator but also recovers metal bearing ore particles that could be lost to the waste dump. The benefits of ore sorting include increased energy efficiency and reduced water and reagent usage in the downstream operations (Bamber, 2008; Gunson, Klein, Veiga, & Dunbar, 2012; Mazhary & Klein, 2015; Robben, Wotruba, Robben, von Ketelhodt, & Kowalzcyk, 2013)."

Jan 1, 2016

By Tom Shumka

INTRODUCTION ?The Electro-Magnetic Crack Detection (EMCD) technique is an electromagnetic inspection method used for detecting and sizing surface breaking flaws. ?It works well on structural material or welds, ferrous or non-ferrous metals. ?EMCD?s rapid scanning is achieved using a hand-held probe. ?EMCD provides reliable crack detection and sizing (length and depth). Cracks can be sized accurately. ?EMCD dramatically reduces most cleaning requirements as there is no need to clean to bare metal. ?EMCD is capable of inspection through thin metallic coatings, or through non-conducting coatings up to 10mm thick. ?EMCD allows full data storage for back-up, off-line view and audit purposes.

Oct 1, 2010

By Franc R. Joubin, Donald H. James

"THE PROPERTY of Rexspar Uranium and Metals Mining Co. Limited is situated within 3 miles of Birch Island, British Columbia, a village on the C.N.R. main line 80 miles north of Kamloops. The claims extend up the south slope of the North Thompson River valley.Prospecting in the area dates back many years. Fluorite was reported in 1918, lead showings in 1926, and bog manganese in 1929. Diamond drilling in 1942-43 indicated more than a million tons of material containing 20 per cent fluorite and 15 per cent celestite in what is known as the 'fluorite zone'. Marketing and beneficiation difficulties have delayed further development of this deposit.Systematic checking of specimens and drill core by the B.C. Department of Mines and the Geological Survey of Canada revealed low radio-activity in the fluorite zone material. Subsequent prospecting with Geiger counters revealed zones of higher radioactivity a few hundred feet distant from the fluorite zone. The property at this stage came under the development direction of Technical Mine Consultants Limited, who undertook a program of diamond drilling. Of the several radioactive zones located, two have so far rewarded development and appear to constitute low-grade uranium orebodies. These are referred to as the ""Black Diamond"" or ""BD"", and the ""A"" zones -see section. Open-pit mining of the thick, dip-slope orebodies appears possible.General GeologyWalker (1) describes the local rocks as metamorphosed sediments cut by granodioritic intrusives and by greens tone. At the property the sequence is:GreenstoneUnconformity or intrusive contact Trachytic member -tuffs, breccia, flows. Argillite -black, thin, not always present. Schist -thin-bedded sericitic quartzite and siltstone with some calcareous layers."

Jan 1, 1949

By S. Itoh, T. Nagasaka, J. Ono

With respect to the recycling of used lead-batteries, a pure lead is required to prepare a lead-calcium alloy electrode for a new maintenance-free battery. The pure lead can be obtained by means of electrolytic and/or pyrometallurgical refining. In the lead electrorefming, antimony is concentrated in anode slime. From the viewpoint of the recycling and recovery of metal values from used lead-batteries, especially from anode slime, oxidation experiments were conducted for pure liquid antimony in the temperature range between 973 and 1373 K to elucidate the oxidation kinetics and mechanism. Furthermore, since lead anode slime generally consists of antimony, lead and bismuth, experiments have been also carried out using antimony-lead-bismuth alloy. The equation relating to the mass transfer characteristics in the gas phase was then applied to analyze the oxidation kinetics. As a result, it was found that the anode slime treatment, that is, an oxidation of antimony concentrated in anode slime followed by vaporization as antimony oxide Sb406, should be operated with higher oxygen partial pressure and sufficient amount of gas flow rate at lower temperature around 1073 K. The feasibility of the oxidation treatment for anode slime has been also discussed.

Jan 1, 2004