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ABSTRACT It is critical that historical processes and concomitant exposures to specific nickel substances be understood because some diseases linked to inhalation of certain nickel-containing substances have a long latency between first exposure and disease onset, and because nickel substances vary significantly in their toxicological properties. A discussion of the smelting history and related processes at Vale Canada’s (Inco’s) Copper Cliff, Ontario, smelter is integral to the understanding of these processes. The post-1950 processing history, equipment, propensity for aerosol formation, operational procedures, and ventilation controls used by Vale Canada in roasting, smelting, converting, and copper-nickel separation is discussed.

Jan 1, 2013

By M. A. Barron, D. Y. Medina, R. T. Hernandez, I. Hilerio

"Chromium Nitride (CrN) thin fihns were deposited on steel AISI 316 substrates with reactive magnetron sputtering method. CrN films were produced under two different conditions. In the first one, the substrate was heated by a d.c. source. At the second coating was applied a negative substrate bias voltage. X ray diffraction, quantitative energy dispersive and scanning electron microscope, were employed to characterize their phases, chemical composition and microstructure. Additionally microhardness was evaluated using a microhardness tester. The results show that the phase formation of CrN thin films in the first case (with temperature) is better. Both coatings presented homogeneous surface. Their compositions shows differences though that gases flow are same. In attention to their hardness, presents an increment if it's compared with hardness substrate.Nomenclature.P Ar =Argon gas pressure during coating.PN2 = Nitrogen gas pressure during coating.Ts = Substrate temperature during coating.T f = Coating melting temperature. (CrN = 1050°C).E=Potential difference.t =Coating time.P=Target power (Cr) in magnetron sputtering de.HV = Vickers hardness.F = Applied charge.d= Average length of longitude of the two diagonals (mm)Introduction.Wear causes losses in materials surface, generating that components of mechanical systems suffer irreversible changes in their properties, causing a faulty operation of the system. It is important to control their effects, measuring and interpreting their causes clearly."

Jan 1, 2013

By A T. Spathis

Corrections are given for “A three parameter rock fragmentation distribution” by A.T. Spathis (Measurement and Analysis of Blast Fragmentation, Workshop hosted by 10th International Symposium on Rock Fragmentation by Blasting, New Delhi, India, November 25-29, 2012 pp. 73-86). Typographical errors in two equations for the uniformity index in the two versions of the original and modified Kuz-Ram model are corrected. It is noted that the modified equation in the original published paper of Cunningham also had the same typographical error. A corrected plot of the dependence of the uniformity index versus the burden to diameter ratio is given. These corrections do not affect the rest of the original published paper.

Jan 1, 2013

By G. Apsey

Eutectic freeze crystallization (EFC) is a novel technique for the recovery of pure salt and pure water from hypersaline waste brines. It is therefore a promising technology for the treatment of industrial waste waters. The impurities caused by crystallizing salt out of multi-component brines by EFC have not yet been investigated, however. To these ends, the selenium impurity found in sodium sulphate, produced from the waste brine of a platinum operation, was investigated. It was believed that the similarity between sulphate and selenate ions allowed isomorphous substitution of selenate ions into the sodium sulphate crystals, which was the likely cause of impurity uptake. It was found that the presence of sodium chloride in the industrial brine promotes the uptake of selenium, while ionic strength of the brine and mass deposition rate of sodium sulphate did not have a significant effect on the selenium uptake. Isomorphous substitution is predicted to be the most significant mechanism by which all impurities will be taken up when applying EFC to other industrial waste brines.

Jan 1, 2013

By Heather E. Lawson

Recent field data providing measured pillar loading from a deep western mine revealed that an increased load transfer distance existed compared to expected values (Larson et al., 2012). Additionally, recent work by Tulu and Heasley (2012) has shown that the abutment angle in deep longwall mines can be significantly reduced as the depth of mining increases. The load transfer distance and abutment angle are both used as parameters to estimate pillar loading in longwall design. To investigate the potential implications of these observations on pillar loading in deep longwall mines, a parametric study using ALPS loading estimation procedures was performed. A supplemental study was conducted using LaModel to further investigate pillar loading at the tailgate. The study found that the abutment angle is particularly important for panels with supercritical geometries. As panels reach a subcritical geometry with increasing depth, the primary influence of the abutment angle is reduced and matched by other factors, including load transfer distance for tailgate loading. An extended load transfer distance was shown to potentially reduce loading on pillars adjacent to the longwall as the loading is spread over a larger area. The results of these studies indicate a need for further field verification and research toward regional geologic influences on pillar loading and how these may impact ground stability.

Jan 1, 2013

By G. Couture, J. -F. Dubé, F. Letarte-Lavoie

"The Xstrata Nickel Raglan concentrator, located in Quebec’s Nunavik region, has been in operation since 1997. Originally designed to process 800,000 tonnes per year of high-grade nickel ore, the plant’s current capacity is 1.3 million tonnes per year due to various optimization projects. In 2011 and 2012, the Metallurgical group, with assistance from BBA, updated and optimized the variables affecting SAG throughput in order to optimize process stability while maintaining maximum plant throughput. This project consisted of reviewing the control strategy and completely updating the pre-existing Fuzzy Logic controller. This paper describes the successful update of the controller including a complete revision of control rules, a new process control strategy and the integration of new process variables, most notably mill rotational speed. It will also show how this new approach has provided a simple and robust way of delivering both an increase in throughput while reducing process variability.INTRODUCTIONThe Xstrata Nickel Raglan Mine concentrator is located in Northern Quebec along the 62th parallel. It has been in operation since 1997 and was originally designed to treat 800,000 tonnes of ore annually. The Raglan Agreement held with the Makivik Corporation and the Inuit communities limits the annual tonnage of ore that can be processed at 1.32 million tonnes.The ore is processed in a 24 foot variable speed, semi-autogenous grinding mill (SAG). The conversion from Autogenous Grinding (AG) to SAG was completed in 2006. Before the ore is processed by the SAG, its size is analyzed by a Wipfrag camera that provides a granulometry estimate. A cone crusher reduces the SAG’s discharge screen’s oversize material. A 14 foot diameter ball mill ensures final grinding before the flotation stage.Many control strategies were used at the SAG over the past few years. Fuzzy Logic was first used in 2007 in order to control tonnage feed to the SAG. This first version only measured the value of the variables without taking into account their rate of change. Revisions were made over the course of the last few years to improve controller performance. Other variables were added such as slurry density and crusher Closed Side Setting (CSS). The previous revision of the Fuzzy Logic was done in 2009 with a review of the rules only."

Jan 1, 2013

By Dan Wang, Qian Li, Yong-bin Yang, Tao Jiang

"Thiosulfate is one of the most promising non-cyanide lixiviants for gold leaching. However, the undesirable reaction between thiosulfate and copper (II) gives rise to increased reagent consumption, which results in high cost and huge limit to its development. This paper presents study on the effect of ammonia, copper (II) and Cu(NH3)l+ ions on the oxidative decomposition of thioulfate. It shows that the presence of copper (II) and Cu(NH3)l+ can significantly increase the thiosulfate oxidation, while ammonia is relatively unaffected. The oxidation of thiosulfate by copper(II) in the absence of ammonia is fast at first and then decreases as time increased within a certain time, which can postulate that an intermediate product is responsible for the decreased consumption. The effect of ammonia is depended on the interaction with copper (II), which was found to significantly affect the consumption of thiosulfate.IntroductionFor over one century cyanidation is widely used in industrial production of gold, due to its simplity of process and low cost of production. However, cyanide is a highly toxic chemical reagent used dangerously and brings serious environmental pollution. What's more, cyanidation has slow speed of leaching gold and poorly leaching effective for refractory ores. With the exhausting of free-milling gold ores and promoted environmental protection requests, the disadvantage of cyanidation becomes a growing problem. In recent years, more and more research activities have been focused on alternative processes using non-cyanide lixiviants. Among the non-cyanide lixiviants, thiosulfate is considered as the most promising one[l-5].Compared to cyanide, thiosulfate is an inexpensive, nontoxic and less-pollution reagent, which can form complexes with many metal ions. Thiosulfate leaching of gold has an acceptable leaching rate and is insensitivity to impurities. Moreover it presents advantage on the treatment of refractory gold ores such as carbonaceous gold ores, copper gold ores, complex arsenic and sulfur gold ores, and so on[6]."

Jan 1, 2013

By Edward J. Sterne

Several shale-hosted Pb-Zn-Ag deposits have been discovered in the northwestern Brooks Range, Alaska. Best known among these are the Red Dog, Drenchwater Creek, Lik, Ferric Creek, Hot Dog Creek, and Competition Creek deposits. They occur in a tectonically disturbed sequence of of Mississippian to Triassic shales, argillites, and cherts, and most are spatially associated with volcanic rocks. The sulfides are hosted in shales as disseminations, banded layers, massive lenses, and crosscutting veins. Detailed geologic descriptions of sulfide prospects in the Brooks Range were given by Tailleur (1970), Nokleberg and Winkler (1978), and Plahuta and Robinson (1979). Lange et al. (1980) discussed the formation of the deposits, the nature of the mineralizing solutions, and the temperature of formation on the basis of sulfur isotope studies. More recently, Harrover et al. (1982) detected a correlation between sulfide mineralization and high-temperature formation of charts associated with the sulfides by oxygen Isotope and chert crystallite size determinations.

Jan 1, 2013

By Ulrich Leiste, David M. Fox

This paper presents the results from small scale testing aimed at measuring the loads on a rigid target due to the detonation of a buried mine. The aim of this research is to find how the impulse delivered to the target varies as the air filled void volume fraction within the soil changes.

Jan 1, 2013

By Ben C. Gerwick

Large diameter steel tubular piles installed vertically or on a slight rake, offer many advantages as the foundations of major overwater bridge in regions of high seismicity. By proper selection of diameter and wall thickness, an optimum balance between stiffness and strength can be achieved. Under strong seismic motion, the piles will deflect and bend so as to reduce the acceleration forces transmitted to the superstructure, while still limiting drift. A major advantage of this concept is that the mass of the footing block is significantly reduced from that of the conventional pier. The design of the footing block requires great care in order to transfer the high shears and moments. Where the soils consist of significant depths of sediments, the kinematic interaction of soils, piles and structures must be considered. Moments will be a maximum just under the footing block. Filling the top portion of the pile with concrete will prevent local buckling and assure ductile behavior even under overload. Typically the piles will be long, with most or all of their support furnished by friction and will require the use of very large pile hammers to achieve the required capacities. Where the piles are founded on rock or in hardpan, sockets will be drilled and filled with reinforced concrete. For these piles, high moments can occur both at the head and just below the rock surface, so the concrete infill should extend the full length. This paper describes the use of tubular piles driven through the deep silty sands of the Jamuna River, Bangladesh, and also where socketed into the near-surface rock for the mail pylon pier of the new San Francisco-Oakland East Bay Bridge in California.

Jan 1, 2013

By Sylwia Zymankowska-Kumon, Rafal Danko, Józef Danko, Mariusz Holtzer

"Burning of ceramic materials is carried out at temperatures 900+ 1300°C, in dependence of the required functional properties. The Faculty of Foundry Engineering together with the Faculty of Material Engineering and Ceramics developed the technology of production of burned ceramic materials with using spent moulding and core sands. The mentioned above waste materials of the foundry industry fulfilled -in plastic masses intended for obtaining ceramic materials -the role of the addition weakening clay raw materials. The laboratory investigations were fully verified by the results of industrial tests. It should be pointed out that none negative effects were observed at the stage of mixing raw materials and preparation of plastic masses. The measurements of exhaust gases emissions performed during burning the products containing spent moulding sands as well as during the normal production did not exhibit any significant differences, which could have indicated the harmful impact on the natural environment.IntroductionSands are used by the foundry industry to make metal casting molds and are a mixture of silica sand, bentonite clay and carbonaceous additives or resins. During the casting process, the molten metal cause thermal decomposition of carbonaceous additives or resins, which results in the formation of potentially hazardous organics, that are emitted to the atmosphere and condense in the molding sand. Each year the U.S. foundry industry landfills about 10 million tones of sand because it is no longer suitable to make metal casting molds. A large high-silica sand content in spent foundry sands (SFSs) generates rational premises for their reuse in other than foundry practice fields. Efforts to divert the SFSs from landfills and encourage their beneficial use in manufactured soils, geotechnical applications, the construction industry (road construction, highway construction), the building materials industry (cement, bricks, limestone manufacture), in the filling of mining cavities or in landfill construction (roads on landfills, permanent covers) are make [1-7]."

Jan 1, 2013

By San-chuan Tang, Wen Chen, Shun-ming Ning, Kan-ping Yu, Qiang Zhao, Xue-yong Xing

"A new type of desilication agent (PA-2) was selected by experiment based on the analysis of the characters of silica gel, and the influence of desilication type, desilication dosage, pH value, temperature and aging time on the desilicating effect was studied. The test results showed that on the conditions that pH was 2.0, temperature was 20""C, aging time was12 hours and the dosage of desilication agent was 0.23%, the desilication rate was higher than 93% in solution.IntroductionVanadium is an important strategic resources, which applies to steel industry and petrochemical industry. The main materials for vanadium product are steelmaking vanadium slag, stone coal and containing vanadium waste catalyst, etc. And stone coal is a low-grade carbonaceous silicified vanadium resource, which is unique material for vanadium extraction in China. Meanwhile, our stone coal reserves is No.l throughout the world.The silica acid solution containing vanadium is produced by acid leaching of raw stone coal or its roasted ore. The silica content of this solution is mostly high, besides, when pH is higher than 2 , the solution is unstable. Furthermore, it is very easy to generate gel substance with the increasing of pH value and standing time. 'Ibis silica gel is composed of colloidal particles with the size in 0.001 - 0.1 um. As a result, it is very hard even impossible for the following operation of solution."

Jan 1, 2013

By Norman Paley, Finn Ouchterlony

Detailed fragmentation data for different blast delay timing tests at the Red Dog mine in Alaska are analyzed. This work is a continuation of previous work in which the crusher output was found to be better described by the three-parameter Swebrec function than by the Rosin-Rammler function. For a crusher model, the x50 variable sufficed to describe changing crusher input while b and xmax could be considered fixed. For the crusher output from aggregated stockpile rock, as measured by digital image analysis using Split-Online, the constancy of b was not as apparent. In this paper detailed stockpile data, single Split data series, and sieved belt cuts of crusher product are analyzed using the Swebrec and truncated Rosin-Rammler functions. The variability of b is confirmed. By using specific fraction passing sizes a shortcut is presented that removes the need to do curve fitting to determine the three Swebrec function parameters.

Jan 1, 2013

By Jian Li, Guo Chen, Bingguo Liu, Hongying Xia, Jinhui Peng, Libo Zhang

"Decomposition of ammonium tetramolybdate to prepare Mo03 using silicon carbide crucible in microwave fields was investigated. The results were analyzed Using TG-DTG and X-ray diffraction. Meanwhile, the effects of heating rat, material thickness, socking time, socking temperature on the structure of preparing Mo03 were studied. TG-DTG curves show that the decomposition process of ammonium tetramolybdate is only one stage, in the temperature range 300-350°C, whose begin to decompose when temperature increases beyond 300°C. The molybdenum trioxide was prepared by thermal decomposition. The quality ofMo03 was not affected under the heating rat is 12°C/min. It was beneficial for decomposition ratio with the lower material thickness, longer soaking time, and higher soaking temperature. XRD curves showed that it is viable method for preparation of Mo03 by decomposition from ammonium tetramolybdate in microwave fields.IntroductionMolybdenum is widely used in national defense, aviation, industrial and agricultural production as rare refractory metal. Molybdenum trioxide is vital raw materials for the process of preparation of molybdenum. The traditional production technology of molybdenum oxide is that ammonium tetramolybdate is calcined in rotary kiln or 4-tube furnace [J,2J. But the longer production time, the higher production cost, the lower furnace thermal efficiency, and bigger the energy consumption, especially the powder is easy to leak, the working environment is poor by using rotary kiln [ 3 l _ The particle of molybdenum oxide is non-uniform by using 4-tube furnace because of the uneven temperature of every tube and the poor exhaust of boat bottom [4l _ However microwave heating is quick and uniformity, it is a meaningful research that the microwave is used in the process of calcining ammonium tetramolybdate."

Jan 1, 2013

By Bing Gao, Zhe Wang, Xiangdong Xing, Xueqi Zhang, Shan Ren, Jianliang Zhang

"In sintering, the flame front speed (bed permeability) and sinter qualities are greatly depended on the feed size, especially coke breeze and limestone particle size. It is well known that coke breeze provides sinter bed with heat to meet the demand of partial fusion and diffusion bonding while limestone reacts with iron ore to generate bonding phase in the sintering process. Accordingly, it is necessary to find the optimum combination of different particle size of coke breeze and limestone to yield sinter associated with better qualities. In this study, sinter was produced in the sinter pot with varying coke breeze and limestone particle size together in sintering of a coarse hematite iron ore. The sintering productivity was measured and all of the result sinters were examined by microstructure analysis and reduction degradation test (RDI test). For the sintering of a coarse hematite iron ore, it was found that the optimum mean particle size combination of coke breeze and limestone was 1. 71mm and 1.55mm in the sinter mix. On such a circumstance, sintering productivity was higher and the properties of sinter were better.IntroductionNowadays, as the main iron bearing burden material of modem blast furnaces, sinter has a great influence on the blast furnace operation. Sintering is a greatly complex process involving various chemical reactions to form kinds of mineral phases [1, 2]. In the sintering process, coke breeze is used for fuel and it generates heat to raise the green bed temperature. Limestone serves as flux and it reacts with iron ore to produce various mineral phases. On one hand, during the sintering process, the particle size of coke breeze can have an effect on temperature, atmosphere, the flame front speed and all of them act on the microstructure and mineral constitutions of sinter [3, 4]."

Jan 1, 2013

By Kameron Ray, Ruilin Yang

This paper compares the modeling results obtained by using a single seed waveform (SS) versus multiple seed waveforms (MS) as inputs to the Multiple Seed Waveform (MSW) blast vibration model. The field data for the comparison was collected at a coal mine. The results of the comparison showed that the MSW model yields more accurate predictions and significantly higher correlation to field measurement when using MS as input. When using a single seed waveform as input, different seed waves result in different predictions of PPV. In contrast, using the multiple seed waveforms as an input, more consistent results are obtained.

Jan 1, 2013

By Bohumir Jelinek, Sergio Felicelli, Mohsen Eshraghi

"We present a parallel lattice Boltzmann - cellular automaton model of the two-dimensional dendritic growth during solidification of binary alloys. The model incorporates effects of solute and energy transport under melt convection. The parallel performance of the algorithm is assessed. A loss in the parallel efficiency is observed when multiple computational cores per processor are utilized. Excellent strong scaling up to thousands of computing cores is obtained across the nodes of a computer cluster, along with the near-perfect weak scaling up to forty thousand cores. The presented solidification model shows a good scalability up to centimeter size domains, including millions of dendrites.IntroductionLattice Boltzmann method (LBM) is an attractive numerical technique for solving fluid dynamics problems. Its advantages are simple formulation and locality, with locality facilitating parallel implementation. In the present model, interface kinetic is driven by the difference between local actual and local equilibrium liquid composition [1]. The cellular automaton (CA) technique is deployed to track the solid-liquid interface [2]. A serial version of the present LBM-CA model with a small number of dendrites was validated against theoretical and experimental results in the previous publications [3, 4]. In this work, it is the first time that simulations with millions of dendrites were performed, something not possible with the computationally much more costly phasefield method [5].This research effort examines a technique for simulations of millions of dendrites in centimeter size domains, including thermal, convection, and solute redistribution effects. Nearly ideal scaling properties of the model are demonstrated. This extensively large landmark was achieved because of• the CA technique being two orders of magnitude faster than alternative, phase-field methods [5]• highly parallelizable LBM method, convenient for simulations of flow within complex and time dependent boundaries• availability of the powerful NSF Extreme Science and Engineering Discovery Environment (XSEDE) supercomputing resources"

Jan 1, 2013

By Cheng Gong-jin, Chu Man-sheng, Liu Zheng-gen, Zhang Yong, Liu Jian-xing, Xue Xiang-xin

"High chromium vanadium-titanium magnetite is one kind of Fe-V-Ti-Cr composite ore resources, which owes high utilization value. Owing to lacking systematic study on the sintering of this ore home and abroad, effects of carbon addition and basicity on sintering process and sinter metallurgical properties, such as sinter yield, vertical sintering speed, tumbler strength, sinter machine utilization coefficient, and low temperature reduction degradation were investigated systematically under laboratory conditions in the paper. The results shows that, when high chromium vanadium-titanium magnetite proportion is kept unchanged as 13% in sintering feeds, sintering process index and metallurgical properties are the optimum under carbon addition 5.0% and basicity 2.70, which meets the requirements of blast furnace burdens. This research provides technical parameters for practical sintering production of high chromium vanadium-titanium magnetite.IntroductionHigh chromium vanadium-titanium magnetite (hereinafter abbreviated as hi§h-Cr V-Ti magnetite), in which Fe is closely symbiotic with Ti and isomorphous with V and Cr1'- l, is one kind of typical vanadium-titanium magnetite resources with high comprehensive utilization value but the difficulties are extremely high due to complex chemical composition and mineral structure. At present, the feasible and mainstream utilization process of high-Cr V-Ti magnetite should be the route of agglomeration-blast furnace smelting. Thus, sintering production is the foundation for high-Cr V-Ti magnetite utilization. However, till now there are few research documentations on high-Cr V-Ti magnetite sintering home and abroad. Under the above background, this study focused on detailed researches of high-Cr V-Ti magnetite sintering. Sintering process uses the powders or fine iron ores to produce artificial rich ore with good metallurgical properties 4l Solid fuel provides 90% heat requirement during sintering15J. The appropriate amount of fuel and flux should be added during sintering in order to provide necessary heat and maintain the desired basicity16l. That is to say, carbon addition and basicity are two key factors affecting metallurgical properties of sintering products17J. Therefore, the effects of carbon addition and basicity on sintering process and metallurgical properties, including sinter yield, vertical sintering speed, tumbler strength, sinter machine utilization coefficient, and low temperature reduction degradation, are systemically investigated under laboratory conditions in the study, on purpose to achieve the optimization of sintering process for high-Cr V-Ti magnetite."

Jan 1, 2013

By José Fernandes De Oliveira Ugarte

El presente texto analiza las diseminaciones de oro a través de la microscopia electrónica de barrido con microanálisis dispersivo. Dicha metodología permite identificar el oro refractario diseminado ( forma nativa y "electrum") en diferentes ambientes mineralógicos. Asimismo, genera informaciones acerca de la composición química, tamaño de partículas y grado de liberación del mineral de valor económico.

Jan 1, 2013

By Robert Hopler

THE KEYSTONE NATIONAL POWDER COMPANY is an Independent organization, incorporated under the laws of the State of Pennsylvania. It has three dynamite mills near Emporium, Pa., with a daily capacity of 165,000 pounds. It maintains branch offices in practically all the largest cities east of the Rocky Mountains, and has distributing magazines located in every section where there is a demand for high explosives, with facilities for wagon deliveries. Our mills are all of modern type and are equipped with the most improved machinery for the manufacture of high explosives. The efficiency of our laboratory in conjunction with the high class of labor employed, has enabled us to put on the market an explosive, the quality of which is the result of extensive research and scientific knowledge. Our modern and complete equipment for harbor and railroad transportation insures our patrons of prompt deliveries, which is an essential feature particularly to contractors and those whose facilities for storage are limited.

Jan 1, 2013