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By Takashi Nakamura, Atsushi Iizuka, Yong Fan, Etsuro Shibata

The level of iron in typical copper slag reaches nearly 40% by mass, in the form of iron silicate. We designed a method to oxidize the nonmagnetic iron silicate to magnetite, permitting the selective recovery of the slag’s iron content by magnetic separation. This would effectively decrease the volume of dumped slag; the reclaimed iron could be used for iron and steel making. The crystallization behaviors of magnetite and hematite were studied as reaction products of the molten oxidation of copper slag. A gas atmosphere of 1% by volume of oxygen was found to effectively precipitate the slag’s iron content as magnetite.

Jan 1, 2015

Caterpillar Inc The world's largest manufacturer of construction and mining equipment, diesel and natural gas engines and industrial gas turbines. Technology leader in logistics, construction, transportation, mining, forestry, energy and electric power generation.

Aug 1, 2013

By D. Nower

"The supply of copper is expected to be at a large deficit in 2012. To recover from these deficits mining companies are required to maximize production and there is no better way to accomplish this than to optimize the use of their mobile mining equipment fleets. To optimize these fleets, each equipment type has to be monitored in its own unique way. Automation would not only improve production, but also minimize the safety risks and eliminate planning errors. The automated vibration monitoring of multiple systems on the shovel can determine the machine’s condition at all times. This reduces unplanned downtime and keeps critical shovels in production. This paper will discuss the details of how shovels can be successfully monitored, continuously. INTRODUCTIONP&H Mining, part of Joy Global, is the world’s largest manufacturer of above-ground mining equipment. Its electric rope shovels, such as Figure 1, with capacities up to 115 tons (104.3 metric tons), are used for high production loading in surface mines; its draglines, such as Figure 2, have bucket capacities to 160 cubic yards (122 cubic meters). P&H also produces blasthole drills, mobile mining crushers and other essential mining equipment. Headquartered in Milwaukee, WI, the company does business on every continent, except Antarctica. ECONOMIC FACTORSDue to the global demands for metals and power, mines are required to operate at full capacity. Mine operations cannot afford any critical assets to shutdown unexpectedly; depending on the ore type and quality, downtime for a single shovel can be as much as $300,000 per hour.Electric rope shovels are one of the most critical assets in open pit mining. They are very large, complex machines with DC or AC motors, multiple reduction gearboxes (some of them complex planetary) and multiple large rolling element bearings. This complexity, combined with the tough 24/7 service, results in too much unplanned shovel downtime, which can affect the entire downstream process."

Jan 1, 2012

By Michael Moser, Brighty Dutta, David Dreisinger

"Molybdenum is widely used in the industries as an alloying element in the manufacture of steels and super alloys. The widespread use of the element encourages a growing need to develop extraction processes for recovery from both primary and secondary sources. The Solvay Group has developed a solvent extraction reagent named CYANEX®600 for the recovery of molybdenum from acidic solutions originating from both low grade (e.g. copper solvent extraction raffinates, smelter dusts and slags) and high grade (molybdenite) molybdenum sources. CYANEX®600 is a purified form of CYANEX®272 with the active component bis(2,4,4- trimethylpentyl)phosphinic acid. The extraction behavior of CYANEX®600 towards molybdenum in sulphuric acid medium was evaluated. The uptake of molybdenum increased with the increase in concentration of CYANEX®600. The approximate stoichiometry of the extracted complex was: Mo: CYANEX®600 = 1:2. Efficient back-extraction could be achieved with 0.1 M disodium EDTA and 0.1 M (NH4)2CO3, thus providing the option of recyclability of the extractant. The detailed back-extraction studies are currently under progress to find out the possible option for complete transfer of Mo(VI) to the aqueous phase so that high purity Mo salts could be precipitated from the molybdate solutions.INTRODUCTION Molybdenum (Mo) is one of the world’s valuable metals and is highly sought after by researchers due to its versatile mechanical, thermal, chemical properties. Swedish scientist Carl Wilhelm Scheele demonstrated molybdenite to be a mineral sulfide in 1778. Peter Hjelm successfully isolated dark metal powder from the mineral sulphide and named it as ‘Molybdenum’ in 1782 (Gupta, 1992). Molybdenum is a refractory metal of silver gray appearance and is an important alloying element used in the manufacture of steels and super alloys. Molybdenum compounds are widely used in formulation of catalysts (Gupta, 1992). Molybdenum occurs in nature only in chemical combination with other elements. Several molybdenum bearing minerals have been identified, but the only one of commercial significance is molybdenite (MoS2). As molybdenum is a strategic metal for the industrial sector, its widespread use acts as a factor for depletion of the natural resources. Hence, there is growing need to develop extraction procedures for its recovery from both primary and secondary sources. United States, China, Chile, Canada, Peru, and Mexico are listed as the main producers by the U.S. Geological Survey, 2016 (U.S. Geological Survey, Mineral Commodity Summaries, January 2016)."

Jan 1, 2017

By M. Santaluce

"The revamp of critical process assets that require a significant plant outage (shutdown) presents a unique and demanding set of challenges for plant operators. They are executed in a more complex Brownfield environment, typically with limited working space and often involve unknown conditions or scope. For plant operators, such a project is often a high cost event both in terms of opportunity cost of lost production and the resource cost of labor and materials. It can also be a high risk event in terms safety, environment, and future plant reliability/availability. This impacts current and future performance or Overall Equipment Effectiveness (OEE). In our experience, the sequential nature of the EPCM approach does not provide the proper framework to facilitate the level of coordination, stakeholder cooperation and detailed planning required to adequately address the construction and shutdown complexity of a critical asset revamp projects. This paper proposes a more integrated approach to handling shutdown revamps of critical assets. Its main thesis is to involve the key performing stakeholder groups early in the project lifecycle (engineering team, procurement team, construction team and plant operations) to form an integrated shutdown management team that is focused on ensuring delivered results are aligned with project objectives. In this model, the construction team executing the shutdown/construction is preparing the detailed shutdown/construction planning concurrently with detailed engineering and procurement planning. This allows construction/shutdown requirements to influence engineering and procurement, with the desire to optimize safety, speed, quality and cost. The paper also discusses how to overcome the procurement hurdle in applying such an approach. The outcome of this integrated approach is better planning, coordination, communication and alignment between the project stakeholders, a shutdown/construction driven planning approach that more fully addresses the challenges of these projects and delivered results that are aligned with project objectives."

Jan 1, 2015

By T. Nomura, N. Saitoh, K. Tamaoki, Y. Konishi

We have developed new recycling technologies, based upon an eco-friendly biotechnology, in order to extract precious and rare metals sourced from end-of-life products and electronics. We have been focusing on the metal ion-reducing bacteria, Shewanella algae and Shewanella oneidensis, that are able to reduce and deposit gold ions (Au(III)) or PGMs ions (Pd(II), Pt(IV) and Rh(III)) into metal nanoparticles at room temperature within 120 min. When processing the aqua regia leachate of printed circuit boards, Shewanella bacteria were able to rapidly and selectively collect gold ions under acidic conditions in the presence of heavy metal ions, proposing a new bio-recovery system for gold. This biotechnological procedure also has the potential to allow the recovery of PGMs from the leachate of automotive catalysts. Shewanella bacteria were also able to successfully perform the complete reduction and deposition of the PGM ions. The ability to collect the PGM ions suggests that this represents a new process for the biorecovery of PGMs from used automotive catalysts. Our proposed biological method enables the rapid and highly efficient recovery of precious and rare metals via separation and concentration utilizing microbial reactions at room temperature.

Jan 1, 2014

By W. Yang, R. Rajasingam, B. Tadesse, K. Mohanarangam

Copper electrowinning is a complex electrochemical process that involves the production of LME grade copper from copper rich electrolyte. The process involves the deposition of the copper ions onto the cathode from copper rich electrolyte with the production of oxygen bubbles at the anode. Acid mist is produced by these oxygen bubbles bursting at the electrolyte free surface. It is an undesired by-product of the Electrowinning process which unchecked could result in mist generation higher than the recommended time-weight-average exposure limit. Various approaches to alleviate the problem have been adopted by companies, all with varying degrees of success. All of these have been attempts to treat the symptom acid mist rather than the inherent problem, often proving expensive and, in some cases, ineffectual. In this paper, a new method was developed for acid mist quantification based on ‘total acid mist’ capture above the EW cell under well controlled conditions. With the use of sophisticated diagnostic analytical tools and measurement techniques it was possible to study all the operating variables including current density, flow rate, temperature, etc. independently and their effect on bubble size, bubble velocity, gas hold-up as well as acid mist generation and its droplet size. Results show that total acid mist capture increases with an increase in current density but remains more or less constant between 300–500 A m-2. Total acid mist also shows an increase with increasing electrolyte temperature. These findings are substantiated with the aid of bubble size and gas hold-up measurements with the transparent EW cell.

Jan 1, 2019

By H. Wotruba, K. Neubert

Dual-energy X-ray transmission (DE-XRT) imaging is known from safety luggage inspections at airports. The use of DE-XRT technology for sorting applications in the primary raw materials industry has been the subject of numerous investigations. Beside other metal ores, X-ray transmission sorting is already used for the preconcentration of tungsten ore, gold ore and coal. The applicability of DE-XRT sorting is limited to ore types where differences in metal concentrations are measurable, based on an interpretation of X-ray images. Metal contents in particles occur in large varieties in terms of concentration, grain sizes, spatial distribution and mineralogy and therefore influence the X-ray absorption. As a result, each ore has to be tested individually for its suitability for DE-XRT sorting. The objective of current research at the Department of Mineral Processing (AMR) at RWTH Aachen University is to assess parameters influencing the detectability of rare earth oxides. Two approaches were followed: (1) Practical test work, based on artificial ore samples of defined compositions and (2) Computer-based simulation of absorption features of identical particle compositions. In total, more than 300 artificial samples of various compositions and metal grades were produced and X-ray images from DE-XRT sorting were analyzed. Results from the DE-XRT sensor were put into correlation with metal grades and particle sizes, to analyze influences and limits on the detectability of rare earth oxides. In addition, a new approach was tested in which the X-ray absorption of particles of various compositions was determined based on a Monte Carlo (MCNP) simulation. During the simulation, similar compositions, as used for the artificial samples, were tested and the X-ray absorption behavior during DE-XRT sorting was determined. A comparison of results from both approaches is used to assess the applicability of the MCNP-simulation for the prediction of the X-ray attenuation behavior during DE-XRT sorting.

Jan 1, 2016

By V. Schwinn, P. Fluess, N. Cauderlier, J. Bauer

From a strategic and economic point of view, the development of fine grain high strength steels for long distance pipelines is intensified world wide to satisfy the demand for natural gas in the future.The project related property profiles based on strength, toughness, crack arrest and sometimes resistance against HIC at defined design temperatures require an effective structural refinement using advanced steelmaking and processing in the rolling mill. The microstructure of modern line pipe steels ranges from ferritic pearlitic to ferritic-bainitic and structures where bainite is the dominant component, possibly upgraded by secondary phases. This paper illustrates microstructures and properties of recent orders on line pipe steels both for onshore and offshore application using different processing routes in the plate mill. Examples will be given for SAWL 485 offshore grades, X65 HIC and X70 HIC onshore grades, respectively. Finally, production results of a recent X80 order will be presented.

Jan 1, 2005

By J E. McMynn

The development of the Granduc mine presents a number of problems which are peculiar to its location and surrounding terrain. Because the development tunnels portal onto an area which is covered by an extensive glacier, and the mountain-side is subjected to dangerous snow slides, it was decided to construct an underground powerhouse to supply the necessary electric power and compressed air. This paper deals with the special problems inherent in the design and -construction of an underground plant. It involves the installation of diesel-electric generating equipment having an aggregate capacity of 1,050 kw.,and of air compressors with a total capacity of 2,400 cfm. Items dis-cussed include the selection of equipment to meet site conditions, the ventilation and cooling of the underground room, and the protection of personnel and equipment from explosions and fire. A short discussion on the automatic supervisory and alarm installation is also included. THE Granduc mine is located 135 miles north of Prince Rupert and 25 miles north of Stew-art. This seems quite accessible, mileage-wise, but, due to mountains,

Jan 1, 1963

By Zhiqing Zhang, Changyun Chen, Qing Liu, Lin Lin, Zhihong Jia, Guangjie Huang, Lipeng Ding

The effect of interrupted quenching (IQ) treatments on natural aging and bake hardening response of Al-Mg-Si alloy was investigated by hardness measurements, tensile test, differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The results show that interrupted quenching at 100oC could effectively suppress natural aging and improve bake hardening response. The optimized interrupted quenching treatment is 100oC for 45min, which gives the alloy a relatively low T4 temper strength and higher bake hardening response. The formation of highly dense cluster(2) during the interrupted quenching could be the reason for suppressing the natural aging and accelerating the precipitation of ß? phase during the paint bake treatment. In addition, interrupted quenching at higher temperature (170oC) results in unfavorable properties in both T4 temper and paint bake treatment. The formation of large precipitates is responsible for these undesired effects.

Jan 1, 2015

By Shuo Zhang, Wenying Liu

"In dump leaching, the efficiency of metal extraction from ores is strongly influenced by the mechanisms of fluid flow. Particle size distribution acts as a fundamental parameter in the determination of fluid flow properties in packed ore beds. In this study, we investigated the particle size distribution in dump leaching by using image analysis technique. The results showed that the particles in the dump varied from smaller than 2 cm to larger than 200 cm in diameter. P80 was calculated to be 200 cm, which was significantly higher than the historical data used by the operation. P25, P50 and P80 were found to increase non-linearly with increasing depth towards the toe of the dump, suggesting the segregation of fine and coarse particles. The image analysis results were verified by applying the rock fragmentation models. The model with the Swebrec function was found to be in better agreement with the image analysis results. Future research will investigate the effect of particle size distribution on the behaviour of fluid flow.INTRODUCTION Fluid flow plays an essential role in the extraction of valuable metals using heap/dump leaching (Amos et al., 2009). The rates of the chemical leaching reactions and microbial activities determine metal concentrations in the leachates and therefore the efficiency of the metal extraction. The reaction rates are influenced by two fundamental processes: transport phenomenon and reaction kinetics (Bouffard & Dixon, 2001). The transport phenomenon refers to the percolation of fluids through channels and pores in a packed ore bed, which carries lixiviants and reaction products to/from ore surfaces by convection and diffusion. The percolation rate of the leaching solution is determined by the hydraulic conductivity of the packed ore bed, which is a function of the permeability and the degree of saturation (Guzman et al., 2008). Permeability, an intrinsic property of a packed ore bed, is strongly influenced by the particle size distribution of the ore grains (Bouffard & Dixon, 2001). Hence, the objective of this study was to investigate the particle size distribution in dump leaching."

Jan 1, 2017

By Hiwa Salimi, Foley. Stephen R, Loghman Moradi

Common water-miscible organic solvents including DMSO, DMF, methanol, ethanol, acetone and THF in combination with HCl and low concentrations of H2O2 were investigated for dissolution of gold. THF showed the best result demonstrating that gold powder could be completely dissolved in 1.5 hours in 1.0 mol/L HCl and 0.2 mol/L H2O2. No complete gold dissolution was observed for the rest of solvents even after 24 hours. The rate of gold dissolution was measured by dissolving gold wire in THF/HCl/H2O2 mixture. The rate of gold dissolution in optimised condition was 75 g m-2 h-1 at room temperature and significantly increased to 590 g m-2 h-1 by raising the temperature up to 60 oC. Although a THF/HCl/H2O2 mixture showed a slower dissolution rate in comparison with aqua regia, however the applied conditions are considerably milder which is highly promising for gold leaching in an industrial scale.

Jan 1, 2015

By D. M. Maijer, S. M. Mohseni, A. B. Phillion

The microstructure evolution kinetics of aluminum alloy B206 during artificial aging has been investigated using non-isothermal calorimetry. A combination of differential-scanning calorimetry (DSC) and tensile tests have been utilized to develop an Avrami model to predict the precipitation kinetics as a function of the thermal processing parameters. The Avrami coefficients, found based on a Kissinger analysis, compare well against those reported in the literature for aluminum-copper alloys. The rapid precipitation kinetics predicted by the Avrami model at temperatures higher than 200°C were assessed through a qualitative comparison against hardness measurement results. In contrast to the continuous hardening observed at 150°C, the material softens with continuing heat treatment at 250°C resulting in an overaged state. This can be attributed to the rapid precipitation kinetics at this temperature, leading to the termination of the precipitation-hardening effects at early stages of artificial aging.

Jan 1, 2015

By G. T. Lapidus, A. Garcés, O. J. Restrepo

"Colombian nickel laterites have historically been processed by pyrometallurgy. However, due to the depletion in ore grades, alternative processes are required. Hydrometallurgical processes, such as pressure acid leaching, have been proposed as alternatives to extract nickel from deposits with suitable characteristics. Such a leaching process requires high concentrations of acid to achieve acceptable extractions, and is not selective. In this study, an alternative aqueous alkaline glycine system has been employed to evaluate the leaching behaviour of a Colombian nickel laterite which contains 1.15% Ni, 0.12% Co and 41.1% Fe. Additionally, the effect of the addition of chloride ions, the use of a reducing agent and the application of a pre-treatment to improve the extraction of nickel were evaluated. Extractions of 4.63% Ni, 42.16% Co and 0.33% Fe were obtained using a 1M solution of glycine at pH 9. In addition, an increase in nickel extraction from 4.63% to 25.68% was achieved by applying a pre-treatment to the sample. The results show that even though nickel dissolution was much slower than in acid leaching, it was selective over other metals such as iron, proving the proposed method to have potential as a process for the extraction of nickel from Colombian laterites.INTRODUCTION Before 2010, most of the industrial operations used pyrometallurgical processes for the extraction of nickel, mainly in saprolitic regions of deposits, with greater contents of the metal. Nevertheless, due to the gradual depletion of such deposits, different hydrometallurgical processes have been studied as alternatives to process those nickel laterites with low grade and those which present problems of refractoriness due to the presence of acid consuming materials (McDonald & Whittington, 2008; Oxley & Barcza, 2013; Wang et al., 2012). However, such leaching processes require high concentrations of acid to achieve acceptable extractions and they are not selective. Facing lateritic nickel ore deposits containing high levels of acid consuming materials, an alkaline leaching medium becomes an advantageous alternative over acidic media, due to the increase in selectivity and decreased corrosiveness and reagent consumption (Tanda, Eksteen, & Oraby, 2017). Unlike conventional acidic reagents used for metal recovery, alkaline reagents can selectively dissolve the desired metal, leaving in the solid residue other elements such as iron, magnesium and aluminum, which are problematic in subsequent stages of metals separation and recovery. Furthermore, there are no serious corrosion problems associated with alkaline leaching, even at higher reagent concentrations, or at elevated temperature and pressure (Ntumba Malenga, Mulaba-Bafubiandi, & Nheta, 2015)."

Jan 1, 2017

By Y. Thibault, L. Morin, R. Cameron, D. Gould

"There are an estimated 50 to 100 million dry metric tonnes of low-grade nickeliferous pyrrhotite tailings in the Sudbury area alone, with an average nickel grade ~0.8% (plus cobalt). Pyrrhotite is a highly reactive sulphide mineral that has the potential to generate acidity; consequently, it is stored in large tailings ponds that require perpetual treatment to avoid the production of acidic drainage. Re-processing this material using bioleaching technologies has the potential to recover valuable metals, while reducing the toxicity, reactivity, and acid generating potential of the remaining residues. CanmetMINING is currently developing a stirred-tank bioleaching process to recovery nickel and cobalt from pyrrhotite-rich tailings. Stirred-tank experiments have been conducted with one tailings sample over a range of pH and temperature conditions, resulting in 80 to 90% and 70 to 80% leaching of nickel and cobalt respectively in 10 days.INTRODUCTION Sulphide tailings may represent a significant financial liability for mining companies as these wastes may produce acidic drainage under some disposal conditions. As a result, the companies must post financial bonds large enough to ensure there are sufficient funds for perpetual management of these wastes. At the same time, there are billions of dollars in metals incorporated into these mining wastes waiting to become valorized. Many sulphide tailings are amendable to bacterial oxidation for metal extraction. Re-processing of tailings using bacterial leaching has the potential to recover valuable metals from waste; and reduce the toxicity, the reactivity, and the acid generating potential of the remaining residue. By reprocessing these wastes there is an opportunity to significantly reduce liabilities and financial assurance bonds, while recovering metal values. There are an estimated 50 to 100 million dry metric tonnes of low-grade nickeliferous pyrrhotite-rich tailings in the Sudbury area alone with an average nickel grade ~0.8% (Peek et al., 2011) plus cobalt and copper. Pyrrhotite is separated from pentlandite concentrates by magnetic separation and flotation. It is already finely ground and has often been segregated from other tailings material, making „mining? relatively inexpensive. This represents roughly (> $100/ton) in contained value, with negligible mining costs. This paper reports on the development of a stirred-tank bioleaching process for recovering nickel and cobalt from pyrrhoitite-rich tailings, which is currently underway at Canmet MINING."

Jan 1, 2017

By B. Drew, K. Budna, C. Wenzl, D. Gregurek, A. Spanring

"The metallurgy of nickel and cobalt and of copper is closely interlinked when processing sulfidic Ni-Co ores and Cu-Co ores. The respective furnaces are typically lined with magnesia-chromite refractories, which are exposed to multiple and complex stresses. The selection of the processing route, furnace type and slag system will be dictated by the specific ore type available, this will determine the individual refractory wear mode. This paper evaluates the common refractory wear mechanisms, namely infiltration, spalling and chemical attack by various slag systems, as well as sulfur attack, as observed when processing primary sulfidic ores. All these wear parameters, which are discussed in this paper, lead to a severe degeneration of the brick microstructure and a decreased lining life. Therefore, a detailed investigation and understanding of the wear mechanisms through “post mortem studies” is an important prerequisite for the refractory producer. Based on such research results, combined with specific process knowledge, appropriate brick lining solutions for nickel and cobalt processing furnaces can be recommended.INTRODUCTION The metallurgical production of cobalt and nickel and of copper is closely interlinked to the mineralogy of the respective ores: cobalt is found in African Cu-Co ores as well as in Co-rich nickel ores (laterites and sulfides). Also, Co-bearing secondary raw materials contain the mentioned elements in different contents. In pyrometallurgical processing of sulfidic ores, cobalt is generally recovered as a by-product during the production of copper and nickel, whereas it is normally not recovered separately during the processing of nickel laterites but remains in the FeNi product. Besides various hydrometallurgical production routes, the pyrometallurgical processes involved comprise smelting (i.e., production of a Cu-Ni-Co-Fe matte in electric or flash furnaces), converting and refining (i.e. removal of Fe and S as well as other elements from matte by oxidation). The ongoing trend to use higher oxygen enrichment in process air enables higher intensity processes but also increases the oxidation potential in the vessel. Therefore, during smelting and especially during the oxidative treatment in converting and refining, some amounts of valuable metals are also transferred to the slag in their oxides form. A subsequent slag treatment is then applied for recovering valuable metals from the slag, namely allowing an economic material stream handling and minimizing metal losses. This is often done in a slag reduction furnace. Additionally, copper and nickel are very good collectors for precious metals and platinum group metals (PGMs) - therefore, depending on the content of these metals, an additional refining process is used to recover these valuable metals from the matte or metal phase (Elvers et al., 1997; Davenport et al., 2002; Crundwell et al., 2011)."

Jan 1, 2017

By E. H. Holm

"This paper is a market-oriented review of the industry's present and forecasted performance, considering some of the principal factors influencing natural resource development. The author illustrates the steady consumption growth of nickel, and stresses the need for a quantitative long-range approach to production, consumption and the supply/ demand balance on a worldwide basis. Objective consideration of this data exposes some popular misconceptions. The possibility of near-term undersupply of nickel is discussed in relation to historically rapid changes in inventories and demand patterns. What is the significance of the increasing reliance on lateritic sources? New• facilities, new processing methods and new product forms are illustrated as further evidence of the industry's determination to satisfy the needs and preferences of nickel consumers. Examples indicate how product forms must accommodate to fast-evolving end-use technology. A review of nickel's price performance is used as a base from which to explore tomorrow's price trends."

Jan 1, 1972

A Joint Venture between Hope Bay Gold Corporation and Miramar Mining Corporation recently acquired the Hope Bay project in Nunavut, which represents the first discovery of a major new Archean greenstone gold belt in Canada since the discovery of Hemlo in 1982 and the Yellowknife belt in 1938. Located some 685 km North of Yellowknife, the Hope Bay Belt is geologically comparable to the other major gold producing regions of Canada. The initial discovery of gold mineralization in 1992 led BHP to acquire virtually all of the Hope Bay belt. Over the subsequent 6 years, BHP expended C$85 million on exploration, including 180,000 meters of drilling, 2.3km of underground workings and a 27,000 tonne bulk sample, as well as extensive environmental and economic studies. Hope Bay Gold and Miramar acquired the Hope Bay property in December 1999 for a cost of C$27 million, considerably less than the C$85 million spent by BHP in exploring the property. They both hold 50% of the project, and share expenses equally. Hope Bay Gold is the manager of all exploration phases and Miramar will manage feasibility, construction and operations. The Hope Bay Joint Venture controls 1,117 sq. km., covering virtually the entire 80 km long Hope Bay and adjacent Elu greenstone belts. We believe that Hope Bay is one of the best-undeveloped gold projects in Canada. Work to date has defined a global resource in excess of three million ounces of gold in three principal deposits, each of which is open to extension along strike and to depth. A C$17 million work program for year 2000 focused on advancing a significant portion of the gold resource to a measured and indicated category. This will provide the basis for initiation of a feasibility study in 2001. The 2000 drill program was one of the largest undertaken in Canada last year, and is a clear indication of our confidence that Hope Bay will develop into a major gold producing district. The majority of the potential mineable areas known to date lie within 350m of surface and would be accessed through a combination of open pit and declines. Currently, development of a 1,800 to 2,000 tpd gold mine producing in excess of 300,000 ounces of gold per year at cash costs below $US200 per ounce is envisioned. In addition, the exploration potential on the 80 km gold belt at Hope Bay is clearly tremendous.

May 1, 2001

By G. Itoh, S. Fukasawa

The Al-Zn-Mg alloys have been known to be susceptible to stress corrosion cracking (SCC), which is based on intergranular cracking arisen from hydrogen embrittlement (HE). The mechanism of HE has not been fully understood yet. In order to elucidate the mechanism of HE, we need to investigate the behavior of hydrogen in the alloys. In this paper, behavior of hydrogen in an Al-5.8%Zn-2.4Mg alloy was investigated by means of hydrogen microprint technique, a method to visualize location of hydrogen emission from specimen surface as silver particles. One side of the tensile test pieces was electrolytically polished and then covered with photographic emulsion. Hydrogen was pre-introduced into the test pieces from opposite side by cathodic electrolytic charging for 30min. Then, the test pieces were stretched with continuing the charging. After that, the specimen was fixed, rinsed, dried and observed with a scanning electron microscope. As a result, silver particles were observed on some grain boundaries.

Jan 1, 2015