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By M Morey

Ok Tedi Mine is located eighteen kilometers from the Irian Jaya border in the Star Mountains, Western Province, Papua New Guinea. Sequential flotation concentrators produce a copper / gold concentrate for market, and a pyrite concentrate for environmental containment, with low sulphur tailings from the pyrite flotation sequence being discharged to river. Strict sulphur assay targets are set for the riverine discharge. Current porphyry and skarn ore blends from open pit operations at Mt. Fubilan will cease by 2017. However, drill cores indicate an economic ore body in the skarn ores surrounding and below the current pit limits. With proposed mining from a western pit wall ‘cut back’ and an eastern pit wall underground operation, potential for ore ageing in sub level cave underground stockpiles is apparent. With little information in the literature, Ore Ageing test work at prefeasibility level consisted of multiple one tonne stockpiles of -50 mm crushed rock. For the bankable feasibility study, a successful test work program was implemented utilizing 40 tonne ROM ore stockpiles composed of exposed pit extensions of future ores. Realistic ageing profiles of Skarn ores were obtained from one tonne monthly samples subjected to laboratory testing. Test work outcomes included:• Similar ore ageing profiles from both the pre feasibility study (PFS) and feasibility study (FS) programs, suggesting ore susceptibility to oxidation has greater effect in ore ageing than rock size for Ok Tedi skarns. • Laboratory rougher flotation of pyrite showed significant variation in sulphur recovery rate, suggesting three classes of pyrite floatability.• Laboratory rougher flotation of both copper and pyrite for up to 19 months ore ageing from 11 stockpiles, suggested three stages in the ore ageing process.

Aug 8, 2011

By Jr. Watts, J. L. Ambs, B. K. Cantrell, K. L. Rubow

"The University of Minnesota and the U.S. Bureau of Mines collaborated to develop and field test a personal diesel exhaust aerosol sampler (PDEAS). The PDEAS was field tested in five underground coal mines that use continuous miners and a variety of diesel vehicles, including diesel haulage and utility vehicles. One mine was surveyed a second time, with the haulage vehicles fitted with a low-temperature disposable diesel exhaust filter (DDEF). Aerosol samples were collected with a variety of instruments, including the PDEAS and the microorifice, uniform-deposit impactor (MOUDI). This paper presents the diesel exhaust aerosol (DEA) concentration data collected in these mines and assesses the impact of diesel face-haulage equipment, with and without exhaust filters, on underground mine air quality.The average DEA concentration at the haulageway location for five mines, determined by the PDEAS, was 0.89 mg/m3, with a standard deviation of 0.44 mg/m3 • DEA contributed 52 pct, of the respirable aerosol at the haulageway location. Use of the DDEF at one mine reduced DEA by 95 pct, with a standard deviation of 6 pct, and filter life averaged 10 h. DEA contributed a large proportion of the respirable aerosol concentrations in mines with diesel equipment, and a substantial reduction was achieved with use of a DDEF. INTRODUCTIONDiesel equipment is gaining popularity in underground coal mines. There are an estimated 1,951 units of diesel equipment in 152 underground coal mines compared with 1,100 units in 110 mines 5 years ago (J).5 This increased use is due to the recognition that diesel-powered vehicles are more versatile, which can contribute to increased productivity compared with their electrically powered counterparts. Approximately 33 pct of the diesel vehicles haul coal, 45 pct haul personnel and materials, and- 22 pct perform other duties, such as roof bolting, rock dusting, and road maintenance. Most mines using diesel equipment are located in Kentucky, Utah, Virginia, and Colorado."

Mar 1, 1992

By Heidy de Oliveira Simões

O objetivo deste trabalho foi estudar as correlações entre o IPM (Índice de Permeabilidade Magnética) das pelotas queimadas, as trincas formadas durante o processamento das pelotas no pelotamento/endurecimento e o FeO de cada amostra. As análises evidenciaram que o tipo de trinca presente na pelota impacta no IPM fazendo diminuir a correlação entre IPM e FeO. O entendimento do fenômeno possibilitou desenvolver uma metodologia para determinação de um parâmetro que pudesse ser correlacionado ao FeO das pelotas de minério de ferro, estendendo sua aplicação ao pellet feed, baseado nas propriedades magnéticas do material. O método consiste em medir a variação da indutância de um solenoide, provocada pela introdução do material que se deseja determinar o parâmetro no núcleo de uma bobina, determinando-se relativamente a permeabilidade magnética das pelotas e pellet feed. Para tal, foi definida uma metodologia nas quais alterações devidas à variação da densidade da amostra, causadas principalmente devido a trincas nas pelotas, sejam mitigadas, garantindo a repetibilidade dos resultados. Assim, foi possível a determinação do FeO das amostras através da medição deste novo parâmetro, de forma mais rápida, fácil e com um custo consideravelmente menor que na química analítica clássica.

Aug 1, 2018

By G. Belardi

This paper presents the preliminary results of a research programme conducted to assess the feasibility of a flotation technique in the remediation of soils severely affected by heavy metal contamination. The use of flotation in soil remediation is a recent practice. The main difficulties are given by the variety and peculiarity of the heavy metal containing species, and also by the grain size. Most of the studies reported in the literature concern the use of conventional collectors, such as xanthates, after a preliminary chemical modification of the metal bearing species through sulphidization. On the basis of the minera-petrographic characterization and of speciation, some classes of reagents have been selected, capable of acting both on metal-bearing species and all metallic cations to be separated. The design of the synthetic molecules has been based on the coordinative properties of the metallic centres and functionalized in order to act as collectors for a wide range of metals independently on their surrounding atoms. In laboratory experiments a sample of stream sediment has been utilized, whose contamination is caused by the runoff from Sardinia mine waste dumps and overflow from the settling ponds. The material showed contamination mainly from Zn, Pb and Cu and to a lesser extent from Cr, Ni, Cd, and Sb associated in mixed particles of Fe and Mn. Flotation tests on a laboratory scale have been performed on grain sizes less than 355 µm in laboratory cell Minerais & Metaux. The effects of the structure of collectors (functional group, chain configuration) as well as of the principal flotation parameters (such as pH, concentration of reagent) on the grade and recovery of heavy metals in the concentrate and in the tailings (remediated soil) have been investigated. The results of the laboratory tests substantially confirm the theoretical premises, and the most effecive reagents found belong to the classes ATP, MBT, MBO, fat acids and phosphates.

Jan 1, 2014

By Thomas A. Simpson, Tunstall R. Gray

The Birmingham district first produced steel from Alabama hematite ores in 1899. Since then, the district generally produced more than 6.0 million gross tons of ore a year to the late 1950's. Production has declined since then to an annual rate of about 1.5 million gross tons. Reserves calculated for the district are sufficient to last many years. Mining in the district is now confined to Woodward Iron Company's Vance and Pyne mines. The rocks exposed consist of about 15,000 feet of consolidated Paleozoic sediments with a thin veneer of unconsolidated Cretaceous sediments in the Vance area. The district is characterized by a distinctively parallel and subparallel, slightly arcuate series of faults and joint systems. In view of available information, it seems reasonable to conclude that the Birmingham red ores are of sedimentary origin, modified to a small extent by diagenetic replacement after original deposition.

Jan 1, 1968

By L. Harris

Los finos de coque son materiales que se producen en toda planta de gas y coque y que no pueden ser usados directamente en los hornos metalúrgicos debido que sus propiedades físicas y quimicas ison ndeseables. En este sentido, los finos de coque se producen en altos hornos de fierro y plomo, donde una capa de carbón sin aglomerar y parcialmente coquificado, permanece en la parte superior de la carga y es durante esta descarga que se separa del coque grueso. Sin embargo, el coque descargado es muy grande para el horno y debe reducirse a un tamaño pequeño. Por tanto, el texto señala que para que el coque llegue a los hornos debe contener más de 20% de finos y en el caso de los hornos de plomo, es necesario que se separe de los finos debido a que puede generar un sofocamiento en el rendimiento de los hornos. Así también, describe la operación de la planta de coque en La Oroya, como las características deseadas del coque.

Nov 20, 1967

By J. Dean Warner

In 1984, as part of a project to evaluate Alaskan occurrences of certain critical and strategic minerals, the Bureau of Mines investigated a columbium-bearing regolith on upper Idaho Gulch, near Tofty, AK. The regolith is derived from weathering of a dolomitic marble and consists mostly of iron oxide minerals with accessory apatite, zircon, xenotime, rutile, monazite, and the columbium minerals aeschynite, columbite, and ilmenorutile. Two regolith lenses contain 340,000 lb of columbium resources at an average grade of 0.07 pct. Calculated composite concentrates from two regolith samples (approximately 200 lb each) contained 53 and 57 pct of the columbium at grades of 0.97 and 0.86 pct, respectively. In each case the grade could be improved to 1.1 pct Cb with a sacrifice of 9-pct recovery. The regolith's mineralogy, trace-element geochemistry, and similarity to descriptions of other columbium-enriched regoliths suggest that the underlying marble may be a carbonatite. The lack of associated alkalic igneous rocks and the stratiform nature of the regolith, however, may be interpreted as evidence for sedimentary origin of the marble. The marble and regolith are a lode source for some of the minerals in the Idaho Gulch placer deposit.

Jan 1, 1986

By Liu Yong

A complex rare metal ore, containing various valuable elements is used in this study. The mineralogy results indicate that the mineral composition of the raw ore is complex, and there are more than thirty-eight kinds of minerals in the raw ore, and the elements, such as Nb, Ti, Fe, REO, Be etc, always form isomorphism relationship. The REO content of the raw ore is 0.45%, and the contents of other rare metals Nb, Ta, Ti and Zr are 0.33%, 0.02%, 0.93% and 2.00% respectively, and the main gangue elements are Si and Al, and their contents are 71.84% and 8.5% respectively. The beneficiation-metallurgy combination process of ?preconcentration-reduction and magnetic separation-acidification and leaching-precipitation? is used to treat the raw ore. The preconcentration of raw ore is realized through high intensity magnetic separation, and the magnetic field intensity is 1.0T, and the rough concentrate with 2.88% REO and 1.95% Nbresidue can be obtained, and the iron recovery is 92.83%, and the REO recovery is 95.87%, and the Nbresidue is treated by hydrometallurgy process of ?acidification-leaching-precipitation?, then the rare earth oxide, niobium concentrate and zircon-bearing residue can be obtained, and the REO recovery is 80.10% and the Nbresidue and the gangue obtained from the high intensity magnetic separation process is separated by gravity separation, and then the zirconium concentrate can be obtained. The indexes of the beneficiation-metallurgy combination process used to treat the complex rare metal ore are as follows. The REO content of the rare earth oxide is 92.58% and the recovery is 58.44%. The Nb2O5 and 27.42% TFe can be obtained. Iron in rough concentrates is removed after reduction and low intensity magnetic separation, then the iron powder with Fe content over 88% and nonmagnetic rare-metal 2O5 recovery is 94.77%. The rare-metal 2O5 recovery is 80.04%. The mixture of the zircon-bearing 2O5 content of niobium concentrate is 28.34% and the recovery is 54.02%. The ZrO2 content of zirconium concentrate is 28.43% and the recovery is 52.35%. The TFe of iron powder is 89.53% and the recovery is 78.13%. Keywords: rare metal ore, separation and extraction, beneficiation-metallurgy combination, comprehensive utilization

Sep 1, 2012

By J. D. Davis

On May 15, 1936, Congress authorized the Bureau of Mines to conduct certain studies, experiments, and. investigations of subbituminous coal and lignite.4/ Appropriations were made in July 19 7, and since that date an active investigation has been underway to complete the provisions of the act. Part of the investigation has included a comprehensive survey of the known properties of the lower-rank non-coking coals, and provisions were made to obtain more data on certain varieties. In line with this plan, a typical subbituminous coal was selected for an extended series of tests in the standard. Bureau of Mines-American Gas Association unit,5/ at the Central Experiment Station. This particular noncoking coal was the first one of its rank that had been tested in the apparatus; for this reason the results are of particular interest because the testing apparatus was originally designed for use in studying the coke- and gas-making properties of coking coals. The test as described below has been developed by the Bureau of Mines since 1927 through a cooperative agreement with the American Gas Association.6/ Ninety to 180 pounds of coal is heated in a circular retort, 13 to 18 inches in diameter, at wall temperatures ranging from 500°C. to 1,110°C. in 100°C. steps. All products are collected and measured; their physical and chemical properties are then carefully determined to ascertain the gas- and coke-making properties of the coal. During the last 10 years approximately 50 representative American coals have been tested in the Bureau of Mines equipment. The results on the first 30 coals and a complete description of the test procedure are contained in a joint publication of the Bureau of Mines and the American Gas Association.7/ The remaining twenty coals have been reported in Bureau of Mines reports as Technical Papers and Bulletins.

Jan 1, 1939

By H. E. Peterson, W. L. Anderson

"INTRODUCTION The great demand for tungsten incident to the war has led to the exploration of a large number of low-grade tungsten deposits. To properly evaluate the low-grade deposits it is essential to have available a dependable method of analysis applicable to all types of low-grade tungsten ores. Results reported on the tungsten content of the ores have often varied quite widely and have led to confusion. The Bureau of Mines has been requested by Government lending agencies and by companies interested in the production of tungsten to publish a general method for the determination of tungsten in low-grade ores. To meet this need, the Bureau of Mines is herein submitting two methods for analysis that have been proved on a large number of tungsten-bearing ores various types in the Bureau of Mines laboratory in Salt Lake City. Also, a third method was developed that requires no cinchonine and has proved to be applicable on most tungsten ores. The cinchonine method is the generally accepted for analysis of tungsten ores. Very reliable results can be obtained by this method if certain precautions are taken, as outlined in this report."

May 1, 1943

By A. J. Reed, W. R. Bergey, Carr. J. M.

"The Highmont copper-molybdenum deposits are at Gnawed Mountain in the Highland Valley porphyry copper district, 125 miles northeast of Vancouver. This district is near the center of the lower Jurassic Guichon Batholith, where a north-trending swarm of porphyry dikes is crossed by west-northwesterly structural belts in which fracturing, intrusion of porphyry and breccia, and mineralization areconcentrated.The Highmont deposits are 2 miles southeast of, and in the same southernmost structural belt as, the Lornex deposit. The main deposits occur on either side of a composite dike of granodiorite, porphyry and breccia which strikes west-northwestward in fractured quartz diorite. North of the dike, the adjacent Nos. 1 (East) and 2 (West) zones together contain 150 million tons of open-pit ore mineable in two separate pits. These two zones will support a 25,000-tpd mill with a grade in the first five years of approximately 0.46 per cent copper equivalent. South of the dike, the Nos. 3 and 4 zones are partly explored and will provide large additional reserves. In these various zones, chalcopyrite, bornite and molybdenite form disseminations and fracture-fillings accompanied by quartz, K-feldspar, tourmaline, sericite, specular hematite and other minerals. Bornite extends for varying distances north of the dike, beyond which chalcopyrite is locally accompanied by pyrite. Higher-grade mineralization tends to coincide with fracture swarms, or with shear zones and faults which largely parallel these swarms. The ore zones are reflected by geochemical soil anomalies which show some glacial dispersion. LP. surveys gave weak but significant responses, expressed as per cent frequency effect. The ore zones occur within a strong magnetic gradient, but do not show a significant magnetic response."

Jan 1, 1971

By Nick Barton

The ability to estimate that support is unnecessary for various dimensions of opening in certain rock mass environments is of particular relevance in the mining industry, where most excavations are not expected to remain open indefinitely. As Hoek1 observes: "the basic aim of any underground excavation design should be to utilize the rock itself as the principal structural material, creating as little disturbance as possible during the excavation process and adding as little as possible in the way of concrete or steel support". Approximately two hundred case records have been analysed for the purpose of determining the amount of permanent support normally used when a given span is excavated in known rock mass conditions Some thirty cases concerned unsupported openings. Excavations that can stand unsupported appear to have certain common characteristics as regards rock mass quality. However, the mechanical properties of the rock mass are not the only factors controlling the choice of design. The dimension of the opening (span or height) and the type of excavation are two important variables.

Jan 1, 1975

By Edna A. Dancy, Gerhard J. Derge

The specific conductance of FeOx,-CaO melts in contact with iron was found to decrease from 200 ohm-1 cm-1 for FeO, to 40 ohm-1 cm-1 for a melt containing 26.3 pct CaO at 1400°C. The temperature coefficient was positive at all compositions, but became smaller at high CaO contents. Current efficiencies for electrolysis increased from 2.5 pct in FeOx to 17.3 pct at the high CaO composition, indicating a change from predominantly electronic conduction to conduction with a substantial ionic contribution. It was shown that Ca++ ions as well as Fe++ ions carry the ionic current. A subsidiary investigation on the apparent effect of atmospheres of argon, helium, and nitrogen on the electrical conductivity showed that this could be correlated with surface temperature losses, which varied with the thermal conductivities of the gases and resulted in precipitation of metal by the reaction 3 Fe++ = 2 Fe+++ + Fe. The work described in this paper is offered as a contribution to the general fund of knowledge concerning metallurgical slags. Measurement of electrical conductivity and electrolysis are comparatively trouble -free methods for investigating molten materials, but, although these methods had been used for complex slags, it was not until the work of Bockris et al.1 that the approach of examining simple binary slag systems was employed, and CaO-SiO2, MnO-SiO2, and Al2O3-Si9 were studied. Two groups have performed work of particular relevance to the present investigation. Inouye, Tomlinson, and chipman2 studied the conductivity of wustite as a function of temperature and of the addition of 5 mol pct of a number of oxides, including CaO. They concluded that molten FeOx in equilibrium with iron is a semiconductor. Simnad, Derge, and ceorge3 demonstrated the ionic nature of liquid iron silicate slags and also concluded that, although the conductivity of FeOx in equilibrium with iron is predominantly electronic in nature, there is a small ionic contribution. The work reported here on FeOx,-CaO slags consists of three main parts, namely, the determination of the specific conductance over a wide composition range, an investigation into the nature of the conductivity through current-efficiency measurements over the same composition range, and an attempt to identify the current-carrying ions, as well as a subsidiary investigation on the apparent effect of the nature of the inert atmosphere on the conductivity. EXPERIMENTAL Materials. The slags, varying in composition from FeOx to 27 pct CaO, were prepared by heating reagent- grade Fe2O3 in an ingot iron crucible with a suitable amount of CaCO3 and, in some cases, powdered iron, in air. This prefused material was then used for the runs. At the end of each run the cell was removed from the furnace and quenched by immersing the bottom half in water. After crushing, the slags were analyzed for calcium and total iron by the usual wet methods. The oxygen content was obtained by difference. Specific Conductance: Apparatus and Method. Fig. shows the experimental setup, with the conductivity cell and leads of ingot iron. The standard four-probe method for measuring high conductivities was used. In this, the potential drop across the unknown resistance is compared with the potential drop across a known resistance connected in series, i .e., same current through both resistances. Thus there are both current and potential leads to the center electrode and to the crucible, which acts as th other electrode. Both ac and dc circuits were available for the measurements; they have been described in earlier work performed in this laboratory.4,5 The geometry of the cell was such that the center electrode was equidistant from the bottom and sides of the crucible. This ensured that the current path was the same irrespective of the magnitude of the conductivity of the material in the cell. Cell constant were measured with KC1 or NaCl solutions, which have considerably lower conductivities (0.0013 to 0.25 ohm-' cm) than the slags, and this precaution in design made sure that the determined cell constants applied to the cells with contents of any conductivity. The cell-constant determinations were made with the ac measuring circuit to prevent polarization. The four-probe method eliminates lead resistance but not the resistance of those parts of the center

Jan 1, 1967

By A. L. Engel

This report is a compilation of results of preliminary concentration tests of nine manganese-ore samples in 1953-1954. Three samples were from Nevada and the other six from California. These samples represent marginal or low-grade ores from deposits that have been mined selectively in the past. The present interest lies chiefly in the possibilities of concentration of the remaining low-grade ores for economical exploitation. The treatment methods included gravity concentration and flotation in most cases. Results were sometimes unsatisfactory, particularly when the ore was too fine grained for liberation of the minerals within economical grinding range. The contaminating gangue minerals, such as quartz and iron oxides, were locked with the manganese to an extent that prevented separation of high-grade concentrates with satisfactory recovery. In cases where fairly good concentrates were made, it was at the expense of recovery, a condition typical of low-grade ores.

Jan 1, 1955

By W. J. Kennedy

Energy management in industry has recently achieved notice as a way to reduce costs without decreasing production. The same approach used in industry can be used in mining, even though the processes are different. This approach is based upon a three phase system of data collection, implementation, and monitoring, all aimed at gathering and evaluating information in such a way as to have a maximum impact on energy costs. This approach has these advantages: (1) attention is directed toward the part of each mining system where the most energy is used, (2) input is collected systematically from all persons involved in the operation of each system, and (3) a means of monitoring the progress toward established goals is created. The mining systems considered are truck haulage, conveyor haulage, blasting and crushing, and lighting. After describing the general procedure, the authors have described a specific method for improving the efficiency (and hence the energy consumption) of round-trip truck haul age systems.

Jan 1, 1982

By D. Yu, Y. Thibault, D. Paktunc

"Prereduction and flux-aided direct reduction of chromite provide significant advantages in reducing energy consumption and greenhouse gas emissions during ferrochrome production. In this investigation, a comparative evaluation of the influences of several alkali fluxes was carried out based on experimental observations supplemented by advanced material characterization and thermodynamic predictions. Direct reduction of a chromite ore with alkali fluxes at 1300°C for 1 hour produced (Cr,Fe)7C3 type alloys with Cr/Fe mass ratios from 0.7 to 2.3. Among the alkali fluxes, reduction aided by NaOH resulted in a high degree (85%) of Cr metallization with the ferrochrome alloy being Cr4.2–4.6Fe2.4–2.8C3. The formation of liquid slag, which facilitated Cr metallization, was limited by the formation of NaAlO2 between 800 and 1300°C. This, in turn, restricted the collection and transport of the charged ionic Cr species (i.e. O2–) to graphite particles. Under the conditions studied, ferrochrome particles were often small and largely unliberated, which would make the physical recovery of ferrochrome challenging. At 1400°C, the amount of liquid slag increased, enabling the growth of alloy particles. Direct reduction of chromite aided by NaOH is promising as an alternative technology to conventional flux-based smelting in electric arc furnaces. IntroductionConventional smelting processes are energyintensive (Riekkola-Vanhanen, 1999) with the energy requirements greater than 4 MWh/t (Naiker and Riley, 2006; Beukes, van Zyl, and Neizel, 2015), and the greenhouse gas emissions can be significant, exceeding 10.5 t CO2 per ton Cr in ferrochrome produced (International Chromium Development Association, 2016). These include emissions occurring on-site (smelter), emissions due to electricity production, and emissions due to upstream processes. Overall energy requirements are influenced by the degree of prereduction and smelter charge temperature. Significant reduction in electricity consumption can be realized if the charge is prereduced before feeding to the submerged arc furnace (Niayesh and Fletcher, 1986). This consideration has led to the development of several prereduction technologies, with the most important example being the Premus process. In comparison to the conventional smelting processes, this prereduction process lowers the overall energy consumption and greenhouse gas emissions by about one-third (Naiker, 2007)."

Dec 1, 2018

By Sebastian Schmuck, Petrico von Schweinichen, Dieter Senk, Mohammad Peymandar

"At Department of Ferrous Metallurgy of the RWTH Aachen University in Germany steels in the system Fe-Mn-C(-Al) are investigated and produced in the framework of the SFB 761 ""steel-ab initio"". A new world of steel grades leads to special challenges regarding the production and recycling at the end-of-life cycle of product. In order to recycle high manganese steel alloys the EAF has to be chosen preferentially. A good slag practice is necessary avoiding loss of manganese content during melting in the EAF. This paper investigates on the reaction kinetics at the interface of slag and steel containing Mn (17-22 wt.-%) and up to 3 wt.-% Al. The effect of changes in the composition of slag and steel on the interfacial reaction kinetics is studied. The thermodynamic software FactSage™ is utilized to calculate the composition of slag and steel at equilibrium.IntroductionTRIP and TWIP steels are highly alloyed steels which show superior strength and ductility when compared to standard carbon steel and stainless steel alloys. These TRIP- and TWIPsteel grades contain typically 15-30 wt.-% manganese, 0-4 wt.-% silicon and aluminum, and up to 1 wt.-% carbon. Steels containing 18-28 wt.-% manganese and 0.7-1.2 wt.-% carbon together with aluminum addition from 3 to 12 wt. -% and without silicon refer to TRIPLEX high manganese steel alloys. These alloys combine high strength at even large ductility [ 1-4]. At the Department of Ferrous Metallurgy (IEHK) of the RWTH Aachen University in Germany, steels in the system Fe-Mn-C(-Al) is under investigation at the collaborative research center, SFB 761 ""Steel-ab initio"". In this project, high manganese alloyed TRIP and TWIP steels are in the focus.The mechanical properties such as high strength and high ductility make this kind of steels perfect candidates for impact absorption applications in auto body such as vehicle doors and bumpers [2, 5]. With increasing the use of TRIP-, TWIP- and TRIPLEX-steels more high manganese steel scraps will be available at the end of life cycle of products, which need to develop the technologies and metallurgical processes to recovery of high manganese steel. A new steel grade brings new challenges in recycling. In order to recycle high manganese steel scraps the electric arc furnaces (EAF) have to be chosen preferentially [1]. Nevertheless it's not easy to prevent the manganese loss during the process in EAF. During the oxygen refining of high manganese molten steel in EAF the manganese content decreases strongly by oxidation and vaporization, which is affected by slag composition, slag properties such as basicity and viscosity, slag weight as well as melt temperature [6-8]."

Jan 1, 2014

The current boom being experienced by mining, coupled with a shortage of professionals, will mean those in the industry will have many choices. It may be easy to become carried away and run with the highest bid or the biggest promise. Without planning, however, the ærightÆ opportunity may be missed and there may be some long-term consequences. There are many choices of paths in the industry to suit work preferences, life cycles and to achieve a balanced life. People in mining have changed jobs and companies frequently û which means new leaders need to take greater responsibility in charting their own direction. Career options need to be carefully assessed and aligned to personal values and preferences. Emphasis is given on gaining site experience early on.This paper examines strategies for career planning, which incorporate life cycles, education and what is meant by a balanced lifestyle. Two tools are identified as being helpful in ensuring strategies can be successfully executed. They are ævisioningÆ and æinfluenceÆ.To make the mining industry more attractive, we need more creative solutions around advances in technology and organisation of work. It also needs the input and leadership of new entrants in to the industry to assist in its survival. New leaders are encouraged to voice a vision and effectively influence their companies. New leaders have little authority and need to learn how to effectively influence. We as a mining industry need to listen, be open-minded and give it a go.

Jan 1, 2004

By John A. Johnson

The first report of investigations5/ in this series pertaining to the investigation of stemming at the Mount Weather testing adit dealt with dust produced from blasting. The present report discusses the effect of stemming on eases generated by blasting, describes the test procedure, and analyzes the results from, blasting 61 standard rounds. Following care the types of stemming that -,re being investigated: 1, No stemming. 2. Sand in 2 paper cartridges. 3. Clay in 2 paper cartridges. 4. Commercial hydrated lime in 2 paper cartridges. 5. Combustible blasting plugs. 6. Ceramic is blasting plugs with clay in 2 paper cartridges.

Jan 1, 1940

By G Cao, Y R. Cui, J X. Zhao, H P. Gui, G H. Wang, Z M. Wang, M M. Ren, B Li

Pyro-metallurgy is still the main process for lead production and a lot of lead direct smelting processes have been developed in recent years. All the processes will experience two steps in common. The first is the oxidisation of PbS to PbO and then reduction from PbO to Pb, furthermore, from ZnO to Zn. So, the composition of melts, especially the slag composition at reduction step change continuously. Up to now, there are few systematic results on the slag physical-chemical properties with its composition change. In this work, the typical lead direct smelting processes were analysed from theoretical and practical standpoints. The full-period slag composition and slag melting point change were compared. Especially, to the PbO and ZnO reduction steps, based on the full-period slag composition change, the slag properties were predicted. Based on dust composition and test results, the mechanism of Pb compound evaporation and its effect on practice and measurement of high PbO bearing slag physical-chemical property is discussed. It is suggested that to restrain the evaporation in practice and to obtain more accurate measurement results of physicochemical properties of smelting slag are the key problem not only to set high efficiency, energy saving process, but also to environmental pollution control.

Aug 21, 2024