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By B. S. Kim, Y. D. Kim, T. S. Kim, T. B. Kim, H. J. Chae

"The Nd-Fe-B scrap was placed in Fe crucible with pure Mg in an Ar atmosphere, and the scraps were melted using an induction heating method. The effects of experimental parameters such as melting temperature (range of 993K to 1073K) and holding time (15min-600min) on the ability of extraction were investigated. The microstructure and diffusion layers were analyzed by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS), and the constituent phases were characterized using XRay Diffraction (XRD). Diffusion of Nd through the Nd-Fe-B scrap into liquid Mg was described, and the diffusion coefficient of Nd in liquid Mg was estimated.INTRODUCTIONNd-Fe-B magnets are usually produced either from comminuted melt-spun ribbons as bonded magnets or hot pressed bulk magnets, or by sintering in conjunction with prior green compaction in an applied magnetic field (Sagawa et al., 1984). These magnets have been widely used for various electromechanical and electronic devices such as voice coil motors (VCMs) and magnetic resonance imaging (MRI) (Samardzija et al., 2012; Matsuura et al., 2006). The production of the Nd-Fe-B magnets is increasing by about 20% per year because of their excellent magnetic properties. However, the expansion of Nd-Fe-B magnet market induced a concern for the scarcity of Nd at the aspect of natural resource. Therefore, the development of an effective recycling process for Nd-Fe-B magnet scraps is an extremely important issue from the viewpoint of resource and energy conservation. Several recycling processes for the Nd-Fe-B magnets have been proposed (Uda et al., 2002; Lyman et al., 1993]. It has been reported that the best separation of rare-earths from the Nd-Fe-B magnets is obtained by sulfuric acid dissolution followed by precipitation of recyclable rare-earth salts. However, this process can make a large amount of waste water including dangerous solutions. Recently, (Xu et al., 2000) have reported a technique to extract Nd from 18Nd-72.4Fe-0.9B-1.82Pr-5.3Dy (wt.%) magnet scrap by using liquid metal extraction (LME) processing. However, these techniques seemed to be difficult for application, because the scraps consist of an infinitesimal amount of other minor elements (Pr, Dy, Cu, Al and Tb), and these minor elements can make a new intermetallic compounds with Mg. Also, some oxides or the plated Ni metal can be preventable to reaction between solid-liquid (S/L) interfaces. For these reasons, the substantive reaction mechanism between Mg and Nd-Fe-B scrap is not clear. In this study, the simple composition of 33Nd-66Fe-1B (wt.%) magnet scraps were prepared using an induction melting process. The effects of the experimental parameter on the diffusion properties between Mg and scraps were investigated to determine whether these methods could be used in industrial application in a liquid metal extraction (LME) process."

Jan 1, 2012

By Christopher A. Jacobs

Project managers aim to maximise the NPV of their projects, but don't always appreciate the relationship between mine throughput, project value and the discount rate being used to evaluate their projects. Rate of production or throughput is perhaps one of the most crucial decisions a project manager must make, but if this choice is made arbitrarily, much effort may be spent on a feasibility study that does not optimise project value. The timing of the study in relation to the stage of exploration is examined and simple techniques are presented that project engineers and managers can use to home in on a production rate which will give their project the greatest chance of success.

May 1, 2006

By Orlando C. Gaspar

The presence of ?ne-grained mineral intergrowths, the complex distribution of deleterious minor elements, and the variable base-metal contents in some assemblages commonly pose technical problems for the processing of volcanogenic massive sul?de ores. The bene?ciation of most massive sul?de ores from the Iberian Pyrite Belt requires extremely ?ne grinding to liberation sizes of K80= 15 µm to 25 µm. For several deposits, mapping of the ore types and metal zoning pat-terns has shown that the different ore types are distributed as ore lenses within the massive sul?des. Mineralogical, textural, and metallogenetic studies have provided an understanding of the distribution of both the vertical and the horizontal metal zonation in the orebodies. Because the ef?ciency of ore processing is affected by ore textures, and because the same mineral commonly has different textures and varies in chemical composition, a relationship between textures of the feed and the middlings must be established for all ore types de?ned at the deposit scale. Quantitative mineralogical methods have been developed to provide, on a timely basis, the information needed to optimize the concentration processes for the massive sul?de ores at the Aljustrel and Neves-Corvo deposits, Iberian Pyrite Belt, Portugal.

Jan 1, 1997

By W. G. Worcester

Generally speaking, the term 'clay' appears to convey but little to the average layman other than of a sticky substance to be rigidly avoided when making a cross-country drive in the family ark- especially so if the chains have been left behind. On the other hand, the technical ceramic; engineer, though his chariot be bogged in the self-same mud-holes, will, more than likely, be planning on ways and means for the conversion of the troublesome gumbo into paving bricks over which all might ride with pleasure and security. However, to come to the point, the term 'clay' bears much the same relation to the ceramic world that the term 'ore' does to the metallurgical; in other words, as there are many kinds of ores, so also are there many kinds of clays, and it therefore becomes necessary to classify and sub-classify them previous to a discussion of their relative values and importance. Hence, a brief digression will be made from the main topic of this paper in order to enumerate and classify a number of the more important types of clays. By so doing, the relative position of Saskatchewan clays, later discussed, will be better understood.

Jan 1, 1929

By M. S. Diederichs, J. Oke

Surface limitations and a need for more direct transportation routes require serious consideration be given to the development of underground construction works in geotechnically unfavourable conditions. Due to geographical and logistical limitations, the construction of these underground works is restricted to difficult ground conditions that require temporary pre-support before excavation in order to avoid tunnel collapse or severe surface settlement. One type of pre-support is the umbrella arch system, which has been gaining popularity due to cost and time commitment in comparison with other pre-support systems (e.g., ground freezing). The umbrella arch system has been employed with significant frequency around the world, yet without a complete understanding about the mechanical response of the system. As such, literature has found the temporary support system to be both under and over designed with regard to safety and/or economical impact. The authors of this paper have made three major contributions to increase understanding of the umbrella arch system and to help optimize the design process. Firstly, the authors have developed nomenclature in order to categorize and define umbrella arch elements and systems, which also stimulated the creation of the empirically driven Umbrella Arch Selection Chart. Secondly, the authors have established a design methodology that is primarily based on advanced numerical modelling techniques to aid in the optimized design of the umbrella arch arrangement for site specific conditions. Thirdly, the authors have developed a semi-analytical model for umbrella arch systems employed in squeezing ground conditions by incorporating elastic foundation theory as well as convergence confinement theory. These three major contributions to such a widely employed tunnelling pre-support system will be introduced and explained in detail, and will include discussion of how each is incorporated in the complete tunnel support design process and throughout the construction and monitoring phase of a project.

Jan 1, 2015

By E. C. Harder

BRITISH Guiana, Great Britain's only South American colony, may be reached by very comfortable steamers, both from North America and Europe. The trip from North American Atlantic ports requires about 12 to 14 days; that from Europe about 18 to 20 days. A number of steamship lines, including Canadian, American, and Dutch, have regular sailings between North America and British Guiana, with calls en route at various interesting ports in the West Indies and northern South America. Moreover, several lines, including British, German, and French, have steamships operating regularly between Europe and the West Indies. Indeed, so popular have the West Indian voyages become in recent years that, during the winter months, special cruises in considerable number are organized for many vessels that ply in the trans-Atlantic service in the summer. A trip to British Guiana, therefore, has become a delightful experience. After visits at the various attractive Leeward and Windward islands and Trinidad, the approach to the low, flat, British Guiana coast, with its muddy coastal waters extending for many miles offshore, is somewhat of a contrast. Arrival in Guiana waters is signalled by the appearance of the modern high-power Demerara Light, located "on a shoal about twelve miles from the mouth of Demerara river. From this point, if the tide is right, a pilot takes the steamer across the bar, eight to ten miles offshore, and into Georgetown harbour. At high tide, the water above the bar ranges from 15 to 18 feet in depth, depending on whether it is neap tide or spring tide; at low tide, the corresponding depths are 9 to 11 feet. As the bar is of soft mud, however, it is usually possible for vessels to pass over it with a draught of about two feet in excess of that indicated by the tide tables. Upon nearing the shore, one sees first the Georgetown wireless towers, then the light-house and the tall chimneys of sugar mills and of various factories in Georgetown, and finally the palms and other tropical trees and the houses of Georgetown itself along the sea shore and the east bank of Demerara river. Extensive wharves operated by various exporting and importing companies stretch along the river bank and activity prevails in Georgetown harbour. The principal exports are sugar, rice, gold, diamonds, bauxite, balata, lumber, fruit and other tropical products. The imports are food-stuffs, wearing apparel, and manufactured materials of many kinds.

Jan 1, 1936

By M. Oliazadeh

The bioleaching of fine low grade copper sulfide ore is described. A sample of ground (> 1 mm) copper ore from Sarcheshmeh, Iran, was subjected to a series of agglomeration procedures and subsequently leached. The best agglomerate was obtained by using lime and sulfuric acid as binders. A column bioleaching test of agglomerated ore was then run for 105 days along with a non-inoculated control column having thymol as bactericide. The results show that about 77.5% of copper was extracted in the bioleaching, whereas the control column achieved only 57% copper leaching.

Jan 1, 2007

By Kim Le Roux

Cemented paste backfill (CPB) is a relatively new material that is increasingly being used in open stope mining across the world. The advantages offered by this high density tailings backfill include: a lower total cost associated with backfill placement, reduction of excess water underground; and the elimination of the need to process the tailings prior to placement. However, almost all backfill design is based on the performance of laboratory prepared samples since it is difficult to obtain undisturbed samples and conduct in situ testing due to the lack of access to backfilled stopes and the safety concerns in accessible areas. The logistical problems associated with conducting in situ testing and obtaining undisturbed samples of cemented paste backfill (CPB) has lead to the reliance in the mining industry on performance data obtained from laboratory prepared CPB samples. The degree to which these laboratory prepared samples represent the actual in situ condition is not well defined, partly because the influence of the mixing, transport and placement process on the material properties it is not well understood. Therefore, there is a need in the industry to understand how the material properties and hence the performance of the laboratory prepared CPB compares with in situ material. This paper reports the findings of an investigation into the in situ properties of CPB at a gold mine in Northern Ontario. A combination of in situ and laboratory testing, conducted on undisturbed samples, was used to quantify the in situ properties and performance of the CPB. These results were then compared to those of a laboratory based investigation of the same CPB. It is evident from this investigation that the bulk properties of the in situ CPB are different from those of the laboratory prepared CPB. The most significant observed differences are that the in situ CPB has a higher void ratio and a lower degree of saturation than the laboratory prepared material. The implication of these differences on the stability and performance of the CPB will also be explored in this paper. 1

May 1, 2002

By K. D. Hester

This paper will review the metallurgical aspects of the completed expansion program at Quirke, and the current rehabilitation and refurbishing program at Panel. During the Quirke program, completed at the end of 1977, the plant capacity was increased from a nominal 4,500 to 7,000 short tons per milling day. The expansion of crushing, grinding, neutral thickening and filtering, leaching, partial neutralization, sand-slime separation, sand washing, C.C.D., clarification, ion exchange, mine water treatment, and tailings neutralization and pumping will be considered. The application of Enviro-Clear thickeners in the mine water treatment circuit and in the C.C.D. will be briefly reviewed. An automatic grinding and classification circuit for limestone will also be covered. The refurbishing program underway at Panel will be discussed. The Quirke and Panel plants will be contrasted and compared. In particular, reference will be made to environmental considerations. The innovative system for producing yellow cake at Panel, LAMIX, will be considered as well as the proposed treatment system for Panel tailings.

Jan 1, 1979

Who is CIBC? ? Canadian Imperial Bank of Commerce (?CIBC?) is a leading North American financial institution. ? Total Assets: US$315 billion ? Market Capitalization: US$29 billion ? CIBC comprises three strategic business lines: ? CIBC Retail Bank ? CIBC Wealth Management ? CIBC Wholesale Bank ? CIBC Wholesale Bank is a leading North American investment bank with niche capabilities in Asia, Australia & Europe. ? 1,000 + employees around the world ? Product range includes: Mergers & Acquisitions advisory and financing, Equity and Debt issues, Merchant Banking and Strategic Lending ? CIBC is ranked as the #1 investment bank in Canada across most of its key products and industries ? #1 Equity Underwriter in Canada ? #1 Mergers & Acquisitions Advisor in Canada

May 1, 2010

By J. C. Heaslip

Introduction The greatest single advance in rock drilling practice since the advent of percussion drills was the introduction of tungsten carbide tipped rock drill?bits. The evolution of rock drills has been a long and highly diversified effort which has culminated in the highly refined ?drilling machines we know today, but because of the spectacular possibilities shown by ?detachable bits, and especially those with tungsten carbide inserts, there is little doubt that the cutting face of .the drilling unit has in recent days stolen the spotlight of rock drilling research and commanded the major attention of the rock drilling fraternity. "Solid" Steels Until about twenty years ago, all rock was drilled with a one-piece rod with a bit forged on one end. In the early years of the art of rock drilling, there was tried every conceivable pattern of :bit from the single-edge chisel to elaborate geometric 'designs. In the end, it was found that a 4-point bit with two sharpened cutting edges crossing each other at right angles would serve best for most rock drilling requirements. For some years thereafter, the main concern of drill manufacturers was .to obtain the best possible steel for drill rods. This was not accomplished as easily as might be thought. The cutting end had to be such that it could be hardened sufficiently to do its work without premature dulling and yet not so brittle as to shatter under the multiple impacts.

Jan 1, 1951

By F. A. Auld

"During the period 1958-1980 seven deep shafts were sunk from the surface in the UK. From 1977 until 1989 sixteen deep shafts were sunk in the UK, all concrete lined. Subsequently from 1989 up to the present day no deep shafts have been sunk in the UK, a period of 30 years. Developments in the design and construction of deep shaft linings in the UK therefore were predominantly carried out throughout the period 1977–1989. This knowledge is recorded in several published papers by the author over that period which will be referred to in the paper. INTRODUCTION The paper includes a review of past precedent for the design of deep shaft concrete linings in the UK and sets out the principles for future designs, including the design load to be adopted and Factors of Safety (SFs) to be used in the design. Hydrostatic pressure increases with depth from the surface and therefore the concrete lining must increase in thickness and strength throughout its depth to resist the pressure. High strength concrete mixes were developed to enable economic linings to reach greater depths and these will be detailed. The ground conditions to sink through in the UK consist of predominantly competent (self-standing when excavated) rock, which can be water bearing, and hence a hydrostatic pressure resisting lining is required. The paper describes the construction measures needed to produce a dry shaft by way of pour length, joint detail, backwall grouting and joint sealing details. PAST PRECEDENT FOR UK DEEP SHAFT SINKING AND LINING Seven deep shafts were sunk from the surface in the UK from 1957–1977 over a 20-year period (Auld, 1987). These are listed in Table 1. Three shafts were for British Coal, two were for Cleveland Potash Ltd and two were for the Central Electricity Generating Board. The British Coal shafts were 5.486 m and 7.315 m internal diameter to depths of 550 m and 780 m, respectively. At 5.5 m internal diameter and a depth of 1150 m, the two Boulby Mine shafts for Cleveland Potash Ltd are currently the deepest shafts in the UK. The two Central Electricity Generating Board shafts of 5 m and 10 m internal diameter, to depths of 255 m and 440 m, respectively, were ventilation shafts for a pumped storage scheme. Six of the shafts were sunk by Thyssen (GB) Ltd and one by Cementation Mining Ltd."

Jan 1, 2019

By A. Brown

THIS P APER has been pre-pared as a progress report on Mines Branch investigations into problems of ground stress in certain co al mines of Western Canada. As such, it should be considered as a companion report to the one ( 1) presented to the Mining Society of Nova Scotia in 1956 and which dealt with similar investigations in the coal mines of Eastern Canada. For the past 50 years, dynamic incidents in the form of 'bumps' and 'outbursts' have been occurring in the coal mines of the Inner Foot-hills belt of tl1e Canadian Cordillera. As these phenomena generally become more frequent with in-creased thickness of overburden, a limiting depth of mining of 2,500 feet has been set (2) for estimating recoverable reserves of coal. If such a view were accepted, from a long-term viewpoint very large resources of coking-grade ?coal -in a part of the continent deficient in such coals -would not be available to the nation. The terrain in which these in-6dents take place may be described in geological terms as being dominated by pronounced structure in strata ?consisting of a large proportion of highly indurated rocks. The Geological Survey of Canada has co-operated by carrying out structural studies (3) at the mines, supplemented lithological by stratigraphic observations.

Jan 1, 1958

By Jean-Paul Drolet

"The ultimate aim of the Law of the Sea Conference, held under the auspices of the United Nations, is to ensure that all aspects of the use of the sea are covered by international law. The question facing the nations of the world can be stated as: "" Who will control and benefit from the use and the wealth of the sea?""The United Nations Conference on Law of the Sea - known as UNCLOS - which reconvened in New York during the latter part of August 1978 was the third such Conference in the UN's history. The concepts of sovereignty over the territorial sea and freedom on the high seas have remained fundamental to the international law o f the sea until our time. The legal regime based on these two concepts developed initially from state practice meant that the unilateral actions taken by one or more countries were eventually accepted and followed by others.It was not until 1958, during the first Geneva Conference on the Law of the Sea (pursued in a second Conference in 1960) that the Law of the Sea was codified and modified to a certain extent by the then independent nations of the world in the four multilateral conventions on territorial sea and contiguous zone, continental shelf, high seas, and fishing and conservation of living resources.A third Conference got under way many years later when the members of the UN met in New York at the end of 1973 for preliminary discussions . This meeting stemmed largely from the need to fill gaps in existing international legislation which did not cover the new uses of the sea. The Conference was subsequently reconvened a number of times - in Caracas (1974), in Geneva (1975) and twice in New York (1976) for what was called "" substantive negotiating sessions."" A sixth session was held in New York in 1977; a seventh, held in Geneva at the beginning of 1978, recessed and reconvened in New York at the end of August 1978. This is what is referred to, in international jargon, as the seventh session of the Third United Nations Conference on the Law o f the Sea. The following dates are the principal markers of a saga which began some twenty years ago with the purpose of regulating the use of the oceans."

Jan 1, 1981

By J. J. Brummer

"A reconnaissance geochemical survey, using the stream sediment technique, is described. The survey covered an area of about 400 square miles, in the Seal Lake area of central Labrador, underlain by basaltic flows, diabase and metadiabase sills, and sedimentary rocks. Previous work had indicated numerous small copper occurrences within the Seal Lake group of rocks. Stream sediments were tested for the readily extractable copper content and total heavy metal content. The results of the copper survey did not yield any new data on the distribution of copper mineralization. Results of the total heavy metal survey attracted attention to a remote portion of the area (Ten Mile Lake), which had hitherto been regarded as having no economic interest. The anomalous values found, suggested that zinc mineralization should occur in this region. Geological mapping indicated that the rocks exposed belonged to the Letitia Lake Group, which is older than the Seal Lake Group exposed to the east, which contains the copper mineralization of the district.Investigation of the area lead to the discovery of: (1) uneconomic lead-zinc mineralization; (2) radioactivity extending over a considerable area. Evaluation of the radioactive rocks led to the discovery of columbium-thorium mineralization in amphibolite and in diopside-actinolite schists along a contact with intrusive alkali syenite.Thus a geochemical survey, which was planned to evaluate a copper province, resulted in the discovery of lead-zinc-columbium-thorium mineralization."

Jan 1, 1960

Accurate hematite solubility data are required to construct predictive solution chemistry models for complex hydrometallurgical solutions. These data are useful in understanding Fe(III) speciation and precipitation in a variety of hydrometallurgical processes. Hematite solubility data were generated in 10 to 70 g/L H2SO4 solutions and at temperatures from 130 to 270°C, using specially modified titanium autoclaves. These measurements represent an improvement over previous experimental data because of better in-situ filtration of the sample aliquots, the approach to equilibrium via hematite dissolution, and the inhibition of Fe(III) reduction on titanium surfaces. Fe(III) reduction was particularly studied to evaluate the inflationary effect of Fe(II) on hematite solubility measurements. Chromate was found to reliably inhibit Fe(III) reduction on titanium. Finally, the generated hematite solubility data were used to construct a solution chemistry model using the OLI software.

Jan 1, 2006

A mini- or micro-machine is a small electro- mechanical device. There are several existing applications of micro-sensors such as the accelerometers used in automobile airbags or the force sensors and grippers used at the ends of micro-surgery tools. Potential applications of existing mini- and micro-technologies are possible and could be used to improve the control and efficiency of fragmentation, heap leaching and other mining and mineral processing operations. A more radical proposition is to devise mass-produced, possibly disposable, minimachines that would operate in large groups. These would be the basis of highly selective, efficient, flexible, and clean mining and mineral processing methods. The paper is intended to promote discussion of how innovative applications of mini-technologies can be used to improve and radically change current mining and mineral processing methods.

Jan 1, 2002

By Z. Bibak, S. Banisi, A. Ghasemi, E. Nematollahi

"The major importance of liners in grinding is their role in providing an appropriate trajectory for the charge. Since it is not possible to study the charge movement by direct observation in operating industrial mills, this task is accomplished by physical (laboratory), and/or, mathematical (software) methods. Because of the high cost and a longer time required for a physical analysis, mathematical simulations have become more common. Simulation of the effect of liner shape on the charge movement has provided a means to select a proper design based on the operational objectives and conditions. Furthermore, the liner shape changes due to wear and impact during operation, which will influence the charge trajectory. This adds more of an incentive to use simulation. These changes in liner could be predicted through liner profile measurements during operation and/or simulation. In this research, an inhouse developed DEM software called KMPCDEM © was used to simulate the charge movement in industrial plant SAG mills. A geometrical method of implementing the shell liners on SAG mills at the Sarcheshmeh (9.75×4.87 m) and the Gole-E-Ghohar (9×2.05 m) operations facilitated the software simulation. Point by point implementation of the measurements of liner profiles of these mills enabled the study to trend the change in the charge movement as the liners wear. Comparison of the simulation to a laboratory mill (1 m diameter) showed that the difference between the measured and predicted charge impact point, shoulder angle and toe angle were 6, 4 and 3°, respectively. INTRODUCTIONComminution is the most energy intensive operation constituting the major portion of operating and capital costs of a mineral processing plant. In the last decade, a vast number of research was aimed at studying various aspects of grinding with the aim of performance improvements (Davis, 1919; Mishra & Rajamani, 1990; kalala, Breetzke, & Moys, 2008). Mill liners transfer the input power to the charge and play a significant role in affecting the motion of the charge (Mclvor, 1983; Mishra & Rajamani, 1990; Radziszewski, 1997; Van Nierop, Glover, Hinde, & Moys, 2001; kalala et al., 2008). Lifters are usually used with mill liners to extend their life and to enhance the grinding and impact breakage efficiency. Mill lifters are used to raise the grinding media and ore to transfer the energy from the mill to the load (Rezaeizadeh, Fooladi, Powell, & Weerasekara, 2010)."

Jan 1, 2016

By Henry Stoch

It?s a green, green world ? Public concern about the impact of human activities on the environment and the roles that businesses play in that impact is rising. What?s happened in the last few months? ? Recent news: ? British Columbia announces carbon tax in 2008 budget ? Federal Court ruling stalls oil sands approvals due to a lack of consideration of GHG implications ? US Energy Independence and Security Act could limit government procurement of oil sands-derived fuels ? Western Climate Initiative (WCI) suggests a ?first seller? approach for regulating generators outside WCI jurisdictions ? Implications ? A cost for carbon has arrived ? The lack of a GHG strategy can have a material impact on your business ? Regulations in other jurisdictions could affect your organization

May 1, 2008

By A. McLean, Q. R. Yang, Y. D. Yang, G. F. Zhang, P. Wu

A considerable amount of waste slag from the pyrite roasting process is discharged every year. Recovery of iron from the waste slag is of great interest for comprehensive use of mineral resource, reduction of environment impact and improvement of economical benefit to related companies. The objectives of the present work are focused on: (1) Compare various procedures for recovery of iron from the waste slag and select a best procedure for industrial trial which is roasting of the waste slag under reducing condition followed by magnetic separation; (2) Investigate the optimum conditions for maximum recovery of iron from the waste slag. The experimental result shows that under the treatment condition found in this work about 36 to 40% of the iron oxide was recovered from the waste slag, where the iron content in the concentrate is 57%. The total recovery ratio of iron, up to 70%, from the waste slag was achieved. After the treatment, sulphur content in the waste slag was reduced significantly and gangue materials, such as SiO2, Al2O3 and TiO2, were reduced effectively.

Jan 1, 2011