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By A. Suzue, T. H. Okabe, Y. Taninouchi

Methods for the physical separation and enrichment of platinum group metals (PGMs) from autocatalyst scrap were studied in order to develop an environmentally friendly and efficient recycling process. In general, an autocatalyst has a honeycomb-structured ceramic substrate that is coated with a catalyst layer containing platinum (Pt), palladium (Pd), and rhodium (Rh). Therefore, physical separation of the PGM-containing catalyst layer directly from the ceramic substrate is favorable for upgrading the autocatalyst scrap. In this paper, the authors present a scrap-upgrade process consisting of electroless iron plating and magnetic separation techniques. Iron was plated on the surface of a catalyst sample used to represent an autocatalyst, which was then crushed and magnetically separated. The Pd in the catalyst sample was successfully extracted and concentrated in the magnetic powder. Under certain conditions, the process increased the Pd concentration by a factor of 4 and recovered 89% of the Pd in the autocatalyst sample.

Jan 1, 2014

By A. J. Hyett, R. D. Reichert

"A laboratory and field research program was conducted to investigate the major factors influencing bond capacity of grouted cable bolts. The results indicate that cable bolt capacity most critically depends on the grout uniaxial compressive strength (UCS), the radial confinement, and the embedment length.In the laboratory &apos;split-pipe&apos; tests were conducted using P VC, aluminum and steel pipes to provide radial confinement, and field test sites were chosen in granite, limestone and shale rock masses. For both datasets higher capacities were obtained under conditions of higher radial confinement. A correlation between the two was obtained through a comparison of the radial wall stiffness of the laboratory pipes with that of the field boreholes as measured using a high pressure dilatometer. Cable bolt capacity was found to increase with embedment length though not in direct proportionality.The use of low water cement ratio grouts (<0.40) can increase cable bolt capacities by 50% to 75%. This effect is maximized under conditions of high radial confinement. However, the use of super thick grout paste (0.30 and less) may be both impractical and undesirable, first because of their limited pumpability and second because of their inconsistency in strength. Grouts with a water cement ratio of between 0.35 and 0.40 are recommended for practical cable bolt applications."

Jan 1, 1992

While this paper is directed towards the ?Bellambie? type of rope attachment, the principles can be applied to any brand of rope fitting however, it is a only a broad outline and the specific installation and maintenance procedures can be obtained from the attachment supplier. The types of attachment to be discussed are:- ?Thimble Type rope cappel ?Wedge Type cappel ?WRC Rope Clamp ? (Rope Glands) ??Hoist and Balance Rope Sockets In each case, the assembly and stripping (disassembly) plus the basic maintenance procedures is briefly described. A guide for Risk Assessment is also included but because of his familiarity with the installation, the end-user is in the best position to draft the final version.

May 1, 2003

By A. Kraly, M. Complojer, P. Paschen, K. Gamweger, H. Antrekowitsch

Increasing quality of aluminium alloys and continuous optimization of the production process leads to an improvement of the gas purging systems. The application of porous plugs for the treatment of liquid aluminum is nowadays not widely used in the aluminium industry especially in Europe. The Department of Nonferrous Metallurgy and the Christian Doppler Laboratory of Secondary Metallurgy of Nonferrous Metals intensified the research and development of refining and alloying processes by gas treatment during the last years. CFD-modeling supports these experiments, which should lead to lower hydrogen content, lower suspended particles and a better distribution of alloying elements in the melt. Different parameters such as temperature, bubble size, gas amount and which kind of gas is used influence the quality of the products.

Jan 1, 2006

By K. Mayhew, A. Lossin, H. Salomon-de-Friedberg

"The proportion of arsenic-bearing copper concentrates that supply the copper industry is on the increase. The current strategy of miners and smelters to blend feeds to reduce average arsenic levels is rapidly becoming unsustainable as more concentrates with even higher arsenic levels enter the marketplace. In addition, the capability of smelters to manage increasing arsenic levels to more stringent and restrictive environmental standards is limited by available process technologies.CESL Cu-As Technology is a viable technical and economic alternative to traditional smelting. It offers the advantage of simultaneous leaching and precipitation of the arsenic in a single processing step while achieving high copper extractions. The process has been piloted in six separate, fully-integrated pilot campaigns for feeds ranging from ~1% to 12% arsenic in concentration. This paper will focus on the behaviour of arsenic in CESL’s leaching/precipitation step and operational factors that influence it, and on the chemical and physical characteristics of the subsequent iron-arsenic residue that represents today’s best available technology from a long-term sustainable (capital/operating costs, metal recovery, safety, environmental) perspective.The examples provided will demonstrate copper extractions approaching 99% and arsenic deportment to residue of 99%. Instantaneous settling rates of the residue were measured at 15+ m/hr. Data from subsequent short and long-term stability testing of the residue confidently support the view that the scorodite-bearing residues from the process will be stable and provide an acceptable arsenic management practice. The technology offers increased revenue and environmental certainty for miners, smelters & refiners to support the development of metallurgically challenged copper-arsenic deposits. Furthermore, results will be presented demonstrating the technology’s ability to successfully incorporate hazardous arsenic containing smelter by-products such as dust into the process feed and simultaneously extract copper value while fixing the arsenic in a stable residue."

Jan 1, 2016

By J. Olaf Sund

"THE November issue of the Bulletin carried in it ""Origin of the New Bruns1viclc Gypsum Deposits"" by J. Olaf Sund. This paper was a digested account of a Master's thesis at the University of New Brunswick which was a very useful compendium of information of gyp-sum in New Brunswick. It was a warded the President' s Gold .Medal and the First Prize in the Graduates' Section of the Students' Essay Competition. The present writer presents his congratulations to the winner of the competition. At the same time he must comment on the use of certain terms and on certain conclusions presented in the paper.The term ""unconformable"" has been used in several places in the paper to describe the relationship of gypsum to anhydrite in various deposits in New Brunswick in a sense which is quite alien to the accepted meaning. It has long been known tl1at the gypsum at the surface or near the surface in deposits in the Atlantic Provinces has come from hydration of anhydrite by surface and ground waters. The gyp-sum must be looked upon then as an alteration or even a weathering product. It cannot in this sense be called ""unconformable"" and thus arguments using the word in the accepted sense are invalid."

Jan 1, 1960

By M. Moghadami

Design and construction of underground openings are associated with many uncertainties with regard to input data. In the construction process of underground openings various levels of risks exist and these affect the safety and profitability of the project. The development of underground openings can be broadly categorized into three major phases of data collection, design, and construction. A significant level of uncertainty is associated with some of the key parameters involved in the aforementioned development phases. Moreover, it is very difficult to evaluate and quantify the effects of uncertainties on the underground project construction process. Additionally, the interactions between important risk elements are typically not well understood. The intention of this study is to develop a general risk model for underground opening projects located in soils and weak rock masses. The goal of the research is to identify and quantify important geotechnical risk elements. Moreover, a weighting procedure will be proposed for the identified risk elements. Finally, all important risk elements will be assembled into a general model with emphasis on geotechnical parameters. The final objective of this study is to apply the proposed model to a real underground project scenario and verify it for actual field conditions. The proposed model, once calibrated properly, will provide a useful support tool for the decision making process.

Aug 1, 2013

By Xiao Huang, Jean-Francois Thibault, Ali Merati, Prakash C. Patnaik

Single-crystal nickel-based superalloys are the current state-of-the-art technology for the manufacture of turbine blades. This technological improvement of the turbine blade has brought a considerable increase in its cost. Repair and overhaul of service stressed single crystal turbine components is an economic necessity for life cycle cost reduction of engines since the cost associated with replacement is significantly higher than its counterpart polycrystalline component. This paper will first review the recently reported research in developing repair technologies used for DS and SX components. These techniques repair the crack or defect while at the same time ensuring that the mechanical properties do not deteriorate and, more importantly, that the single-crystal microstructure is not jeopardized. It will then be followed by a brief overview of the research conducted and initiated by the authors with regards to the repair of single crystal alloys.

Jan 1, 2004

Advanced high temperature electrochemical systems such as fuel cells, electrolyzers and ionic transport membranes are currently being developed for a wide variety of energy conversion, storage and gas cleanup applications. These systems offer high electrical efficiency, multi fuel capability, modular construction, no/negligible emissions (SOx, NOx, VOC, particulate matters) with capability to sequester green house gas emissions (GHG). Electrochemical processes and electrode reactions will be discussed. Cell and stack component materials and fabrication processes will be presented. Bulk, surface and interface degradation processes responsible for cell and stack performance degradation will be examined.

Jan 1, 2005

By K. Morikawa, K. Asano, J. Yoshitomi

The quality requirements for ladle shrouds have become stricter year by year to the pursuit of higher productivity and improved quality in the continuous casting of steel. The ladle shrouds must be sufficiently durable under severe conditions, such as operation without preheating and during several sequential castings. The consideration is that ceramic fibres, which have been applied in shrouds for thermal insulation during casting, could pose a risk to the worker&apos;s health. We realized materials for the ladle shrouds which show high strength and low elasticity. At the same time pursuing effective insulation, a coating which contains no fibres (Foaming Coat) has been developed, replacing the conventional one containing fibres. These materials are durable under conditions of repetitive use and consequently satisfy the customer&apos;s demands. The ladle shrouds which were improved in this way have achieved an excellent durable life in hot service of three times that of conventional ones. This paper reports the recent technological developments in ladle shrouds as well as their performance under hot operating conditions.

Jan 1, 2004

By T. Navessin

Recent research activities in proton exchange membrane fuel cell (PEMFC) have significantly improved the performance per unit cost and its lifetime. These activities narrow the technology gaps, and thus, enable commercialization in some applications. One particular focus is in the development and understanding of proton conducting membrane materials. Many novel membranes are being developed which provide control and systematic understanding of complex relationships between chemical structure, morphology, physicochemical properties, and electrochemical kinetics. In this study, different classes of proton conducting membranes suitable for portable and automotive applications were evaluated in an operating PEMFC at the Institute for Fuel Cell Innovation, National Research Council. Analysis of these results may provide constructive feedbacks to the material researchers.

Jan 1, 2005

By F. Rosenblum, P. Spira

"Self-heating of broken sulphide ore or waste rock underground can lead to ignition and cause serious problems in a mine operation. An extensive study has demonstrated that it is caused by oxidation of certain species of pyrrhotite. Self-heating was found to take place in two stages, first progressing from ambient temperature to 1000C with exothermic formation of elemental sulphur in the presence of moisture and oxygen, and proceeding to a second stage in which the sulphur oxidizes to SO2. Ignition may eventually follow. An apparatus was developed to assess the propensity of sulphide rock to self-heating and the potential for hazardous behaviour. The effect of temperature, time, rock size, and surface treatment with chemicals is presented. On the basis of these results, possible approaches for preventing a runaway reaction are suggested for further investigation.IntroductionThe oxidation of sulphide ore, waste rock or tailings backfill, which may cause hazardous conditions underground through heating, oxygen depletion and, in some cases, fire, is well documented (Farnsworth, 1977; Ninteman, 1978; Rosenblum et al., 1982; Reimers, 1987). The self-heating mechanism, nevertheless, has not been satisfactorily explained. The onset of heating from ambient temperature, in particular, has not drawn the attention of researchers. In the course of a previous study (Rosenblum et al., 1982) aimed at finding a method to assess the hazard from using sulphide tailings as backfill, the authors developed an apparatus to measure self-heating rate under controlled, near ambient conditions. This has since provided decisive information in backfill investigations in the Noranda Group.The test methodology devised for tailings failed to predict self-heating in a broken waste rock known to be active. Upon repeated testing, however, a freshly crushed sample began to exhibit appreciable heating and oxygen uptake (Fig. I). After 14 tests, the self-heating rate reached a plateau of about 4O°C/h and then fell progressively to < 5°C/h after 30 tests. It was hypothesized that weathering in the presence of moisture and oxygen during testing had caused the onset of self-heating. Active tailings, on the other hand, are exposed to natural surface oxidation and need not be weathered to show heating. Based on this finding, a new apparatus was developed capable of simultaneously weathering a sample of rock and monitoring its self-heating behaviour."

Jan 1, 1995

By T. R. Eger

The Load-Haul-Dump (LHD) vehicle is a trackless, free-steered vehicle used in underground hardrock mining to move large quantities of ore/rock to haulage trucks, ore dump locations, or crushing stations. The purpose of this paper is to show, through case study examples, how principles of human factors can be applied to improve the overall design of the LHD vehicle to enhance line-of-sight (LOS), improve posture and decrease whole-body vibration exposure (WBV). Vehicle modifications (larger cab windows, lower engine profile, smaller buckets, angled radiator profile) can lead to improved line-of-sight. The use of secondary viewing devices, such as cameras, can also improve line-of-sight and allow the operator to adopt a more neutral sitting posture. Seating systems that are suited to the underground mining environment can result in vibration attenuation and less vibration transmitted to the LHD operator. The connection between vehicle design, line-of-sight and driving posture needs to be considered in order to continue to improve the design of the LHD and enable the operator to work in a neutral posture with minimal vibration exposure. Changes leading to improved line-of-sight, vibration reduction, and a neutral sitting posture will lead to fewer LOS related accidents and decreased risk factors for musculoskeletal injury.

Aug 1, 2013

By Simon D. Handelsman, Malcolm Scoble, Marcello Veiga

"Abstract - In many mining areas, potentially profitable mineral projects can be at risk because local people do not trust their governments and mining companies on many issues, including human rights. Projects will continue to be vulnerable to potential failure, delays, and higher costs. This paper suggests that geoscientists need to be aware of the global challenges they face from issues of corporate social responsibility, sustainable development, and human rights. These are not areas in which geoscience education has traditionally focused.This paper examines the types of conflict concerning human rights that are encountered by geoscientists involved in mineral exploration and development. It provides a background to human rights issues and presents a classification of the types of issue encountered. It reports on a survey of case studies that provide examples of the breadth, complexities, and consequences of such issues. The paper then concludes by outlining the development of codes and standards to improve performance, and suggests approaches for positive, practical engagement."

Jan 1, 2003

By R. D. MacEchern, M. C. Rockwell

"This paper describes the research and tests carried out to recover the readily available barite from the tailings produced by the Nystone Chemical Ltd. operation at Debert, N.S. The tailings comprised 70-80% of the original feed and contained about 20-25% Baso4 .The objective of the research, undertaken during 1982, was to produce a barite concentrate which would meet the American Petroleum Institute (API) barite requirements for use in drilling mud. Samples from the tailings pond were examined and analysed to determine the tailings characteristics.Preliminary test work was performed on the tailings samples using a Haultain Superpanner, Wilfley tables and Humphrey's spirals. The grade of the barite concentrate retrieved did not satisfy the API barite requirements.The fineness of the tailings and the fact that approximately 80% of the barite was contained in the -200 mesh (0.074 mm) size fractions, indicated that flotation of barite from the tailings might be successful."

Jan 1, 1984

By Lindsay A. Robertson

The long term management of acid generating tailings at mine closure is a common issue, however, management of ARD is significantly impacted by local conditions, including climate. Acid generating tailings, over time, will produce acid rock drainage (ARD) if left exposed to water and air, which both contribute to the sulphide oxidation process. The long term closure of tailings storage areas is a concern from both environmental and engineering perspectives, with long term acid generation and dam stability the main risks. Several approaches can be taken to minimize ARD from tailings facilities using cover systems. Three tailings facility cover case histories, in areas of net positive water balances, were investigated using unsaturated flow modelling software to determine the long term potential for limiting ARD by increasing saturation of the tailings and decreasing oxygen ingress. Each case study demonstrates the importance of integrating the tailings dam engineering into tailings cover closure design. Model predictions are compared to measured saturation levels to assess the accuracy of the calculations.

May 1, 2011

By Lee Barbour

Waste-rock piles from metal mining operations are comprised of large surface deposits of unsaturated, coarse-grained soil and rock. The unsaturated condition and heterogeneous, coarsegrained nature of these deposits make them difficult to monitor or characterize. Key parameters that must be evaluated include; volume-mass relationships (e.g. water content, air content, porosity, density, degree of saturation, grain-size), transport properties (e.g. air-permeability, gas diffusion, hydraulic conductivity), geochemistry (e.g. solids, gas, and fluid phases) and soilatmospheric fluxes (water and gas). This paper describes some of the techniques that have been developed to characterize waste rock piles for uranium mines in Northern Saskatchewan. For each technique, the method of measurement is described, and preliminary field data are presented and discussed.

Nov 1, 2002

By John G. Henning

Low quality rock is encountered in many manifestations in underground hard rock mines, ranging from weak and poorly consolidated rock to highly altered or foliated rock. Lateral mine developments driven in low quality rock pose on-going challenges to a mine operator, as ground stability issues, such as caving of under-supported ground, drift closure due to surface deformation or buckling processes, and degradation of exposed rock surfaces are a persistent concern. For many operators, ground support design is an iterative process, as support practices are refined with time. Using case studies from a variety of underground hard rock mines, this paper reviews techniques for the classification of low range rockmasses and examines the rationale and effectiveness of adopted ground support systems.

Oct 1, 2010

By J. Bhattacharya, S. K. Mukhopadhyay, S. K. Pal

"While time and again many authors have categorically stressed the restoration of the environment, very little effort has been made in the mineral industry to develop the economy of environmental control. There are many abatement procedures that search a maze of variants. Among them pricing environmental damage seems to be more logical and easily implementable.IntroductionMining as an operation has a severe impact on the Earth&apos;s natural resources. While economical environment control is much sought after, solutions are often varied and complex, and can differ in the problems of single or multiple mine sites.Determination of Optimum use LevelsIn “mining environmental control"" it is required to strike a balance to find optimum use levels. The solution is to find where the welfare benefits equal the cost involved to curb the degree of environmental damage (Fig . I) . In the mining industries this can be done by modifying the production/extraction process itself. For most pollutants, the marginal costs of control will exceed the benefits from further reduction of damage long before the zero pollution damage point is reached (Fig. I). From an economic perspective the optimal alteration of environment by mining would occur at z; pollution continues to be caused by ""zy"" control units, but it would be inefficient to pursue the redemption efforts further because the marginal cost involved would exceed marginal welfare benefits."

Jan 1, 1992

By F. Schulz

NA&apos;s primary smelter has continually increased its production output in the past decade, making it necessary to improve the lifetime of the casting moulds for copper anodes. The current throughput of more than 1,100,000 tonnes per year of copper concentrates amounts to an output of about 450,000 tonnes per year of anode copper at NA&apos;s Hamburg plant. The anodes are cast on a single casting wheel with 24 anode moulds. Besides the stable chemical analyses, the reproducible geometry of the anodes is an important precondition for the success of the subsequent electro-refining process. The anode moulds are subjected to thermally-induced alternating stress and side reactions with the melt. Typical signs of wear will be shown and discussed. Different processes to produce anode moulds will be introduced and the results in terms of their lifetime and the quality of the anodes themselves will be discussed. Finally an outlook is given on possible efficiency improvements.

Jan 1, 2007