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By P. Erskine

"Hyperaccumulator plants can be utilized as ‘metal crops’ in agromining operations. This emerging technology produces ‘bio-ore’ by growing ‘metal crops’ on sub-economic ore materials, such as natural ultramafic soils. In a typical application plant material is periodically harvested, followed by air-drying and incineration to produce the bio-ore intermediate. The bio-ore is of very high grade (>15 wt. % nickel), and of high purity, and may be processed into a number of different products (including nickel metal, nickelbased catalysts and pure nickel salts). Current research efforts from our team focus on Mediterranean climate field trials (Albania, Spain) and tropical climate field trials (Malaysia, Indonesia). Field-scale demonstrations are required to provide evidence of real-life performance and of economic viability. If the trials are successful, agromining may in the near future support local livelihoods with income opportunities as an alternative type of agriculture: to farm nickel.INTRODUCTION AND BACKGROUNDHyperaccumulators, plants with the exceptional ability to uptake and concentrate trace elements in their shoots, can be utilized as ‘metal crops’ in agromining operations (Van der Ent et al., 2013a; Chaney et al., 1998; 2007; Baker et al., 2010). Agromining produces ‘bio-ore’ from harvested ‘metal crops’ grown on unconventional resources such as natural ultramafic soils (Van der Ent et al., 2015a). The bio-ore is a high purity and very high-grade (>15 wt. % nickel) product intermediate that may be turned into a range of different nickel products (nickel metal, nickel-based catalysts and pure nickel salts). The potential for agromining is greatest in tropical regions (Asia-Pacific Region: Indonesia, Malaysia, Philippines, Papua New Guinea and New Caledonia) where very large expanses of ultramafic soils exist (Van der Ent et al., 2013b). Agromine operations may replace existing marginal agriculture on poor ultramafic soils, for example oil palm plantations that require high fertilizer inputs to be profitable, or take place under a cocropping regime. The ability of ‘metal crops’ to achieve high nickel concentrations in biomass (and hence in harvested bio-ore) from soils with just <0.5 wt. % nickel, makes it possible to access non-conventional resources, not accessible by traditional mining techniques. For example, agromining could be implemented both on the large ‘halo’ around the mine leases, and as part of the progressive rehabilitation process after conventional resource extraction. As with all methods for resource extraction, agromining will be finite due to the diminishing concentrations of nickel in the zone accessible by plant roots (Chaney et al., 2014). Nevertheless, considering soil materials with 0.2 wt. % nickel and ‘metal crops’ with a yield of 100 kg nickel ha-1 the agromining venture may be sustainable for decades (Van der Ent et al., 2015a)."

Jan 1, 2016

By J. Stumper

The control of the distribution and movement of liquid water is crucial for increased reliability and durability of PEM fuel cells: whereas the proton exchange membrane requires a minimum amount of liquid water for optimum operation, water excess in the GDL will impede reactant gas access to the catalyst layer thereby reducing performance. In order to understand the relationships between water management on one hand and fuel cell performance and durability on the other, Ballard has been developing a number of minimally invasive techniques that can throw light on the role of liquid water for both cell performance and durability. This paper introduces a novel measurement method that can provide information about the amount and distribution of liquid water under operation. It is shown how the MEA Resistance and Electrode Diffusivity (MRED) method can be used to determine i) the amount of liquid water in the fuel cell, ii) the pure ohmic cell resistance and iii) the O2 -diffusivity of the cathode. Furthermore, through a combination of the MRED method with current mapping it is possible to determine spatially resolved MEA resistance profiles.

Jan 1, 2005

Introduction Gold Mining is an Important Economic Activity in Canada n Total value added during 1990-99 was $15.5 bn n The gold price is an important factor in the value added process n The gold price affects gold mining output, profits, exploration expenditures, employment, etc. Some Factors that Affect the Gold Price n The value of the US Dollar affects the US Dollar price of gold: a weaker US$ correlates with a higher gold price n Supply affects the gold price: the higher the supply on the market each year, the lower the average gold price that year Central Bank Gold Sales n Yearly central bank gold sales add to supply, and affect the price of gold negatively n The negative impact on the price of gold reverberates through the Canadian gold mining industry n Despite the modest amounts, even Bank of Canada gold sales affect the Canadian gold mining industry

May 1, 2003

By Asbjørn Solheim

The service life for aluminium reduction cells is often limited by the cathode carbon, due to preferential wear along the periphery of the cell leading to the so-called "W" wear pattern. The reason for this preferential wear is not well understood. Two mechanisms are suggested in the present paper; 1) non-stationary dissolution of aluminium carbide into a layer of sludge that periodically forms and disappears, and 2) electrochemical formation and dissolution of aluminium carbide within an aluminium carbide layer containing bath-filled pores. The latter mechanism may be related to the high local current density at the periphery of the cathode.

Jan 1, 2011

By David W. Mogk, Tamara Darsow, Macgregor L. Fogelsong, Robert M. Hunter, Frank M. Stewart, Edwin H. Abbott, Courtney A. Young

Abstract: Development of cost-effective techniques for recovering precious metals from their ores has been the goal of metallurgists for hundreds of years. Today, metallurgists are increasingly called upon to design processes for ores that are refractory to conventional recovery techniques. These challenges and the addition of environmental costs (including site remediation) to the total cost of mining have stimulated a search for alternatives to conventional processes, such as cyanidation. This paper describes the progress made to date in development of an innovative alternative to cyanidation, termed bisulfide leaching, for extracting gold, silver and platinum-group elements from refractory ores and concentrates. While bisulfide leaching can be implemented abiotically, significant benefits accrue from its practice as a bioprocess that integrates the steps of precious-metals liberation and extraction. In many applications, bisulfide leaching appears to offer significant advantages over the traditional cyanidation process. Dissolved bisulfide and hydrogen sulfide are much less toxic than dissolved cyanide and hydrogen cyanide. Recommended workspace exposure limits and harmful concentrations for hydrogen sulfide gas are higher than those for hydrogen cyanide gas. While the facilities required to practice the bioprocess on an industrial scale would be similar to that of cyanidation plants, chemical reagent costs could be 80 percent less. The bioprocess may also offer advantages in the leaching of ores and concentrates that are not amenable to cyanidation. For example, bisulfide leaching of ores containing carbonaceous material may produce higher gold recoveries if the "preg-robbing" characteristic of the material can be controlled biologically or with dissolved sulfide binding. Moreover, in that precious metals are much more soluble than base metals in bisulfide solutions, bisulfide leaching offers distinct advantages over cyanidation for selective dissolution of precious metals from base-metal concentrates. Thus, the bioprocess uses the natural sulfur cycle to mitigate pollutant production and to enhance precious-metals recovery.

Jan 1, 1998

By Eugene Sun, Qiang Xu

This presentation will review current applications of composite materials in aircraft design and discuss the challenges involved in maximizing the potential of the composites in aircraft applications.

Jan 1, 2010

By Gerald H. Luttrell, Lance Christodoulou, Jaisen N. Kohmuench, Michael J. Mankosa

The efficiency of the froth flotation process has long been known to be strongly dependent on particle size. For sulfide minerals, good recoveries are typically achieved in industrial flotation circuits for particles in the 30 to 200 µm size range. Particles outside this critical size are typically lost in industrial operations and rejected to tailings streams due to inherent constraints associated with the physical interactions that occur in the pulp and froth phases of conventional flotation equipment. In response to these limitations, a series of experimental studies were conducted to determine whether particles previously lost as tailings could be economically recovered using a suite of novel flotation technologies developed for upgrading ultra-coarse and ultra-fine particles in the industrial minerals industry. For the case of ultracoarse particles, a fluidized-bed flotation system called the HydroFloatTM separator was tested. The data obtained using this novel flotation device in both laboratory- and pilot-scale trials showed that good recovery of previously lost sulfide values up to 850 µm diameter could be achieved. Similarly, for ultrafine particles, a high-intensity cavitation-based column cell was tested. This technology, which utilizes highshear contacting of slurry and gas, was capable of recovering valuable ultra-fine sulfide that were previously lost due to the low capture efficiency of conventional flotation processes. The objectives of this article are (i) to describe the unique operating principles of these two advanced flotation technologies and associated ancillary classification equipment, (ii) to present laboratory- and pilot-scale experimental test data showing the metallurgical benefits of the proposed novel flowsheet for sulfide tailings processing, and (iii) to provide a generic cost-benefit analysis of the proposed system for recovering lost values in existing sulfide tailing streams.

Jan 1, 2016

By Abdelhak Bentriou

The choice of tool for the first well of an oilfield or gasfield is an important factor, given that we will be drilling with the same type of tool for the entire phase and explains why we need to have another type for comparison based on the efficiency of the tool and its ability to crush the rock, and the wear of different types of tools. Development of theoretical and practical tests to determine the optimal regime for drilling is required to take into account the characteristics of rock layers crossed. Classification of boring tools is based on the geometry of the teeth and depends on the hardness, the abrasiveness of rocks as well as their hydraulic system, but it is better to classify them according to the working conditions with a coefficient designating a discriminant. This is called physical characteristic of the drilling tool. The goal is to designate each element of the tool by a coefficient. Results were obtained from laboratory tests. Modeling the initial rate of progress by different types of tools allowed us to determine an adequate mathematical model of the speed initial progress in clean conditions. Using experimental data and statistics we have established the mathematical model of the average speed of progress as a function of time. With these equations we can determine the wear evaluation and analysis of these factors as an approach to classification according to their characteristics. The main equations for the selection of drilling tools will be based on the optimization of drilling parameters for each type of tool. After analysis, we choose the tool that gives a better forward speed with an optimal load and axial rotation.

Aug 1, 2013

By Mario Giavani

"IntroductionBy the 1980s, the continuous casting process had almost replaced the ingot casting of steel in Japan, Europe and North America. While economic benefits were probably initially the prime motivator, the transition rapidly proved that continuous casting in conjunction with ladle metallurgy offered a much greater degree of process control and made possible routine steel specifications not previously available.This new technology demanded improved procedures for the quantitative addition of the required metallurgical reagents, especially as regards the more volatile or toxic elements such as calcium , boron, carbon, sulphur, lead and tellurium. The injection of a thin steel tube containing the additive into the metal bath of a ladle refining station offers the best procedure for this. In the industry this has been referred to as ""Cored Wire "".Operators using this technology find that they are faced with balancing the injection speed against the small cross section of the tube to feed the required amount of reagent within the short time span available to the operation. Large-ladle shops requiring major quantities usually resort to multiple machines and high speeds. Many machines approach a maximum feed rate of 400 m/min. Higher speeds exceed the melting rate of the system, and the ferro static buoyancy of the tube will cause it to coil up the ladle wall and possibly resurface into the slag layer, and even eject itself above the surface. Under these conditions, exact control of element recovery becomes difficult, especially with the commonest addition, calcium silicon alloy.Many experts are persuaded that the final melting position of the carrier tube has major importance in establishing consistent element yield to the bath.For instance, the vapour pressure of calcium at l500 °C is close to I bar. Reaching a melting depth sufficient to accommodate this value is considered to be critical to achieving an acceptable and reproducible yield.Many studies have elaborated semi-empirical formulae to establish the melt zone depth, connecting this value essentially to the diameter of the tube , the injection rate and the superheat of the steel. The author&apos;s experience in steelmaking could not confirm such formulae in many cases, and he set about to develop a mathematical model which would be useful in addressing this problem, taking into account the several parameters which will regulate the behaviour of a filled tube immersed in molten steel."

Jan 1, 1991

By N. Depountis, Th. Rondoyanni, N. Sabtakakis, K. Kavoura, G. Tsiambaos

"Some typical landslide phenomena in Western Greece, in terms of the geological composition and structure of the affected materials, induced by heavy rainfalls are thoroughly studied and analyzed. The studied cases involved composite landslides on Flysch and Neogene weak rock materials that constitute the most critical landslide prone geological formations in Greece. The studied cases named Platanos, Platanitis and Karya include representative landslide sites as regards to the geological composition and structure of the displaced formations. Thus: (a) flysch formation includes different lithological units as shales, marls, siltstones, sandstones and conglomerates and is closely related to the Alpine orogenesis, suffering intense past tectonic movements and (b) the Plio-Pleistocene sediments include clayey marls, marlstones and siltstones. The investigated landslides , affecting mainly transportation routes, are closely related to heavy rainfalls induced by extreme meteorological events and are controlled by active fault tectonics. Long term movement monitoring using borehole inclinometers and surface benchmarks showed that landslides control was effective only when the proper stabilization measures were taken.INTRODUCTIONLandslides represent a major threat to human life, property, infrastructure and natural environment in most regions of the world. They are recognized by the scientific and politic authorities as having a major socio-economic impact and they represent a significant hazard for the population and the properties in particular locations. Landslide hazard expressed as the probability of occurrence within a reference time period and is a function of the spatial and temporal probability (Varnes, 1984; Guzzetti et al. 1999; Lee and Jones, 2004). The spatial probability of landslide initiation (susceptibility) is mainly related to static causal factors (slope inclination, material properties, etc.), while temporal probability is mainly related to dynamic causal factors such as rain input, increased groundwater levels and drainage, earthquakes, etc. (Van Westen et al. 2005)."

Jan 1, 2015

By M. Reza Bateni, M. Zandrahimi, J. A. Szpunar

Titanium aluminides and nickel aluminides offer the potentials, as coating materials, for high temperature and aerospace applications. In this research, attempt has been made to develop Al-Ti and Ni-Al intermetallic compound coatings on the surface of Inconel 738. The coatings applied through pack cementation and simultaneous diffusion annealing processes. Scanning-electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDAX) and grazing angle X-ray diffraction were used for evaluating of coating structure. It was demonstrated that the pack cementation technique could be used to develop TiAl3 and AlNi intermetallic compounds coating on Inconel 738 substrate. When pack cementation technique is based on a halide-activated pack with aluminum and titanium powders, the coating consists of TiAl3 intermetallic compound phase. Whereas, by pack aluminization of Inconel 738, the coating consists of AlNi intermetallic compound phase.

Jan 1, 2004

By O. A. Ojo, R. G. Ding, M. C. Chaturvedi

In this study, the fusion zone microstructure of tungsten inert gas weld of a directionally solidified NhAl-base alloy was examined by the standard metallographic techniques involving the use of optical, analytical scanning and transmission electron microscopes equipped with energy dispersive spectrometer. Fusion zone cracking was observed to be closely associated with interdendritic secondary solidification microconstituents identified as consisting of y, y&apos; and NiMo (Y) phases. Depression of solidification temperature to the terminal ternary eutectic reaction temperature of the system during cooling is suggested as an important factor contributing to the fusion zone cracking.

Jan 1, 2006

By M. W. Bartley

"The Steep Rock iron mine is 141 miles west of Port Arthur, Ontario, and 50 air miles north of the Vermilion iron range in Minnesota. The property lies 27'2 miles north of the village of Atikokan on the south line of the Canadian National railway.The orebodies underlying the bed of Steeprock lake, since de-watered, were known to exist 60 years ago. References to the possibility of iron ore at this location were made in early geological papers and reports. In 1937 the locations of the orebodies were determined by dip-needle surveys, and from 1938 until 1943 diamond and churn drilling were carried on to prove their extent and configuration. It was found that the ore, in addition to being associated with definite types of wall-rock, was controlled by structural features, such as faulting and brecciation. From this geological knowledge the presence of other deposits has been inferred, and these are now being explored and developed.Production at the property commenced in October 1944. During that season 17,000 gross tons of ore was shipped. In 1945, 506,000 gross tons and in 1946, 830,000 gross tons was mined and shipped. In 1946, 164,000 gross tons additional was placed on stockpile for future shipment.TYPES OF 0REBODIES AND MINERALIZATIONThe orebodies at Steep Rock iron mine are tabular. They have an average width of 250 feet, lengths up to 5,000 feet, and persist to known depths of 1,200 feet. They are replacement deposits in brecciated carbonate rock at the contact of underlying pseudo-limestones and overlying volcanics. The ore is composed of hematite and hydrous hematite in the form of goethite, turgite, and limonite. These minerals replaced the brecciated host rocks metasomatically as a result of hydrothermal action. The replacement followed a definite structural pattern along the unconformable contact between the sediments or other rock (now replaced by carbonate) and the volcanics, subsequent to disturbances in the form of minor faulting and shearing. The faulting and shearing provided the channels through which the replacing solutions percolated. It is believed that the late basic intrusions outside the ore zones were genetically responsible for the introduction of the ore-bearing solutions."

Jan 1, 1954

By A. Ghahreman

Activated carbon is proven to be able to catalyze arsenic oxidation in aqueous solution under acidic conditions. A commercially available granular coconut shell based activated carbon (AC) has been evaluated for catalysis of arsenic oxidation in this study. The rapid small-scale column test (RSSCT) has been developed to simulate and predict the performance of a carbon-based arsenic treatment system in a pilot scale reactor. Effects of residence time, aeration rate, and initial arsenic concentration in the influent solution on the AC catalysis of arsenic oxidation under dynamic and continuous conditions were studied by manipulating these parameters during RSSCTs. The effectiveness of the AC on arsenic oxidation was examined over the course of constant diffusivity based RSSCT operation. Residence time and initial arsenite concentration are proven to be the most effective impacting parameters on the arsenic oxidation process. For the 218 min residence time, the highest steady-state arsenic oxidation efficiency achieved was 98% with 1 g/L As(III) being treated at pH=1 under 0.05 L/min oxygen aeration. In a long-running RSSCT, the oxidation efficiency did not seem to deteriorate over a course of 666 hours operation, corresponding to 13986 mL total influent throughput volume. INTRODUCTION Arsenic is toxic to both animals and plants and inorganic arsenicals are proven carcinogens in humans. The increased extraction of low grade and complex mineral resources has introduced high ratios of arsenic into metallurgical processes. Discharge of arsenic by acid mine drainage resulting from mining activities has added intensive pressure on the need for proper treatment (Lawrence & Higgs, 1999). Since trivalent arsenite is more toxic and has lower affinity to solid surfaces for adsorption, many treatment systems initiate with an oxidation step to convert arsenite to arsenate and reach the ultimate immobilization of arsenic by the following precipitation of arsenate (Nazari, Radzinski, & Ghahreman, 2016). Scorodite precipitation has been studied extensively as a means of arsenic immobilization due to its high stability and negligible potential of releasing arsenic (Filippou & Demopoulos, 1997). As a stable ferric arsenate mineral, crystalline scorodite can contain up to 30 wt% arsenic (Paktunc, Dutrizac, & Gertsman, 2008). Arsenic must be in its pentavalent oxidation state in order for scorodite to be precipitated via oxidizing ferrous ions (Clancy, Hayes, & Raskin, 2013).

Jan 1, 2019

By Tong Gao, Jingyu Qin, Xiangfa Liu, Zengqiang Li, Yaoxian Zhang

"The recycling of aluminum materials is a green industry while Al–Si–Fe is a typical scrap aluminum alloy. The key point of recycling Al–Si–Fe alloys is to separate Al and Fe. A method by introducing Al–Si–Fe alloy into Mg melt has been investigated in this work. A separation layer with gathered Fe–rich and Al–poor Fe3Al0.7Si0.3particleswereobtained at the bottom of the cooled ingot, indicating that ß–Al5FeSi phase evolves to Fe3Al0.7Si0.3,and quantities of Al are released to the upper Mg matrix simultaneously. However, the evolution of Al3Fe by adding binary Al–Fe alloy into Mg melt is different. It is supposed that element Si plays an important role in the phase evolution procedure, thus affects the performance of this method.INTRODUCTIONThe rapid development of aeronautic, automotive and aerospace technologies strongly depends on the consumption of materials while sustainable development is the future direction. Aluminum is a recyclable material and Fe is one of the most common impurities. Fe can be introduced into Al alloys by adding low–purity alloying materials and by using unprotected ferrous crucible, tools, or equipment (Belov, Eskin, & Avxentieva, 2005; Lu& Dahle, 2005).For instance, wear–resistant rings are usually inserted into piston head when producing Al–Si pistons and an infiltration procedure by putting the cast iron rings into Al melt before casting is always essential. As a result, both the re–melting of pistons and the reuse of Al melt for infiltrating rings lead to the enrichment of Fe element, which can be even high to5 wt.%(Viala, Peronnet, Barbeau, Bosselet, & Bouix, 2002).It is widely known that coarse ß–Al5FeSi particles will form in high Fe–contained Al–Si–Fe alloys which is harmful for the mechanical properties. In the past decades, several methods to eliminate the harmful effect of ß–Al5FeSi have been investigated which can be widely referred (Munson, 1967; Lee, Kawamura, Inoue, Cho, & Masumoto, 1997; Suárez–Peña& Asensio–Lozano, 2006; Eidhed, 2008).These methods can be divided into two kinds. One is to aggregate and remove the Fe–rich phase through the methods of centrifugation, gravity filtration or magnetic separation. The other way is modifing the morphology of flake–like ß–Al5FeSi by overheating the melt or adding neutralized elements. However, these traditional methods are rarely used due to respective disadvantages, while the commonly used method in industries is using primary aluminum for dilution. However, only less than 30wt.% of scrap Al can be added into primary Al melt for each melting work while it also results in the decrease of product quality simultaneously(Zhang, Liu, & Liu, 2016)."

Jan 1, 2018

By Michael L. Wayman

Native copper is copper which exists in nature in elemental, metallic form, rather than being chemically combined as is the case with the more usual oxides, sulphides, carbonates, etc. Several other metals, including gold, silver and platinum also occur in native form as do, rarely, iron, lead and mercury; a few naturally occurring native metal alloys, notably electrum (gold-silver) and tumbaga {gold-copper or gold-silver-copper) are also known. An analysis of the relative availabilities of native metals as nuggets in a useful size range111 shows native copper to be by far the most abundant of the native metals, exceeding both gold and silver by at least two orders of magnitude. While such an estimate is crude, it serves to illustrate why copper was one of the first metals to have been used by ancient peoples. Native copper is known to occur on all inhabited continents, although its exact occurrence and abundance in ancient times cannot be unambiguously determined because many surface deposits may have been totally exploited and are therefore no longer identifiable. It is clear, however, that native copper does or did occur in all areas inhabited by the early metal-using cultures, for example in the Andes, in Central America and in the Near East. It is remarkable that most of the world&apos;s native copper occurs in the deposits of the Lake Superior region, primarily on the Keweenaw Peninsula of northern Michigan and on Isle Royale, an island in Lake Superior some 50 miles north of the Keweenaw deposits. Canadian deposits of native copper are found in Newfoundland and Labrador, Nova Scotia, Quebec, Ontario, British Columbia, the Yukon and the Northwest Territories (on Victoria Island, Bathurst Inlet and the Coppermine River area). It was to locate the latter deposits that the explorer Samuel Hearne was sent overland from Hudson&apos;s Bay in 1770; they were also surveyed by Sir John Franklin&apos;s expeditions in the 1820s.

Jan 1, 1999

By Wataru Inagaki, Kozo Kawano, Tetsuya Ando

Cu–Ni–P alloys are the typical precipitation-hardening material. Thus, Cu–Ni–P alloys is expected to apply alternative materials for heat-exchanger tubes. Therefore, it was investigated that the effect of the heat-treatment simulated brazing on mechanical properties of Cu–Ni–P alloy in this study. The hardness of specimen as heat-treatment simulated brazing after solution heat treated (sht) was shown approximately 105 HV. The peak hardness and tensile strength of the specimen as performed aged at 498 K for 43.2 ks following the heat-treatment simulated brazing achieved at approximately 140 HV and 260 MPa, respectively. From these results, it is expected the application to higher-strength tube for heat-exchanger after brazing in a furnace. INTRODUCTION Copper prices have increased dramatically with high in recent years. At the same time, manufacturing industries are required to reduce the environment load by reducing the wall thickness of the copper tubes used in heat exchangers. High-strength copper alloys are developed for reducing the wall thickness, while achieving high strength, of the copper tubes. Moreover, excellent workability and corrosive durability are also required by these copper tubes. Furthermore, the brazing, which are carried out at about 1050 K during the assembly process of heat exchangers, leads to grain growth and re-solving of additive elements. Nomura et al. achieved a tensile strength and Vickers hardness of approximately 260 MPa and 110 HV, respectively, after aging at 723 K for approximately 36 ks. Tamagawa et al. studied that the strength of Cu–Ni–P alloy rapidly increased at about 125 HV during the cooling process after the heat brazing due to the Ni2P precipitates sized 5–10 nm. Furthermore, Inagaki et al. achieved a Vickers hardness of approximately 130 HV by aging at 498 K for 10.8 ks. In the present study, we focused on the lowest aging temperature of 498 K in the previous study, and investigating the effect of heat-treatment simulated brazing on the mechanical properties of the Cu–0.93 mass%Ni–0.24 mass%P alloy.

Jan 1, 2019

By David J. Forrester

Light metals, most commonly aluminum, magnesium and titanium, and alloys containing them, are used in many industrial applications where lightness, hardness, ductility and resistance to corrosion are needed. However, these metals and their alloys can be potential ignition sources in underground coal mines. There have been documented cases in the past where coal mine explosions have been attributed to firedamp/coal dust ignitions involving light metals or their alloys. When light metals and their alloys are brought into contact with oxygen bearing material, such as iron oxide (rust) in the presence of heat, then a "thermite" reaction can occur. This source of heat can be generated from frictional contact or from merely a glancing blow. This paper outlines the hazards associated with light alloys, how to address the hazard and regulatory aspects.

May 1, 2001

By L. A. Wolff

"Second only to profitability (but not always), productivity is the most sought after measurement for any operation. Whether it is in mining, manufacturing, construction, etc. managers always strive to know how productive various plants are. Even the Federal Government publishes, on a monthly basis, the nation&apos;s factory productivity.Just what is productivity and how is it measured? This is an important topic that needs definition. There could be as many definitions as there are people who use it. In the mining industry, the problems of defining productivity would be analogous to the definition of equipment availability. Each mine uses its own definition to suit its needs. Webster&apos;s Dictionary primary definition for productivity is ""the quality or state of being productive,"" with productive defined as ""yielding or furnishing results"". This is a definition open to a broad spectrum of interpretation. A discussion of how productivity is currently used in the mining industry and an introduction to a potentially different approach to its measurement and meaning is outlined in this paper.Defining ProductivityTypically, mining companies track several productivity measurements. These are partial measurements and can include the following: tons per specific equipment class per hour, tons per man-hour, and tons per shift. None of these, however, track the over -all performance of an operation, that is, a unit of output per unit of input.For a mining operation, output can be defined as the ore for mill processing. Input includes the required components of production to get to the first step of processing.The Wesbter&apos;s Dictionary definition exposes a major fault with the popular conception of productivity. The critical issue of accountability is not addressed. Anyone can produce, but how effectively and efficiently are resources used? Quantifying an inclusive measurement is difficult. Statistics referring to an increase in productivity are often published. For example, the statement, ""gold productivity has increased by 10%"" has many potentially dangerous interpretations. One must ask, what does this statistic really mean? Did gold companies produce 10%” more gold? Were less manpower or equipment required to produce an equivalent amount of gold? Did ore grades increase resulting in more ounces of gold produced, etc. Obviously, production and productivity can have similar implied applications and meanings, but also two different, distinct meanings.To mitigate a problem like this, a standard needs to be developed within the mining industry. Because of varying ore grade, changing waste to ore ratios, different mining methods, etc. all of which have a direct impact on mining, development of a standard is difficult. Kendrick(1) discusses the use of Total Factor Productivity as a productivity measurement. Summarized, the total factor productivity measure is an indication of the change in efficiency in the use of basic labour and capital factors associated with an operation.This measurement has little meaning when calculated at a given point in time. It should be an on-going calculation, tracking an operation over a period of time, to evaluate trends. These trends can be used to determine if an operation&apos;s productivity is what it should be, and alert management to potential problems before they become major and adversely affect an operation."

Jan 1, 1990

By M. Tanaka, H. Narita, T. Fuchikami, K. Morisaku, K. Nagao, T. Yoshida, K. Kuroda

The effect of various N-substituents on the performance of amide-containing tertiary amine compounds in the extraction of Rh(III) from HCl solutions was investigated to optimize the structure of these compounds for industrial use. It was found that N-2-ethylhexyl-bis(N-di-2-ethylhexyl-ethylamide)amine and tris(N-di-2-ethylhexyl-ethylamide)amine, which have long, branched alkyl chains, were suitable for Rh extraction, because they were soluble in a practical diluent (80 vol% n-dodecane?20 vol% 2-ethylhexanol) and stable against highly concentrated HCl/Rh solutions, and showed high selectivity for Rh(III) over Pd(II) and Pt(IV).

Jan 1, 2014