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By Yang Jian-guang, Deng Zi-xiang, Zhang Xu-liang, Li Jun-yuan

"Hyperaccumulator biomass harvested after heavy-metal phytoremediation must be considered as hazardous waste that should be contained or treated appropriately before disposal or reuse. As a potential method to detoxify the biomass and to convert this material to a suitable bio-energy resource, the hydrothermal upgrading process was applied to remove heavy metals and upgrading crude bio-oil from Pteris vittata stems and leaves harvest. Parameters such as material granularity, temperature, Liquid/Solid (L/S, ml/g), pressure, duration and catalysts were examined for their effect on the removal efficiency of heavy metals and upgrading efficiency of crude bio-oil. Maximum heavy metal removal efficiency of>99% and crude bio-oil upgrading efficiency of 83% were attained with an 200 mesh (75 µm) granularity, LIS 40:1and23 MPa at 380°C in the presence ofO.l mol L-1 K2C03 for 30 min. GC-MS analysis results show that the resulting bio-oil mainly consists of benzene 11 %, ketone 42%, alcohols 14%, alkene 15% and ester 11 %, etc., and the relative molecular weight distribution lies in 94-282, carbon number distribution lies in 6-18, calorific value is 32MJkg-1.IntroductionPhytoremediation of soil or water with hyperaccumulator has been extensively explored in recent years [1-4]. Living plants can clean up soils or waterways. This approach exploits the ability of various plant species to thrive in high metal environments where large amounts of toxic elements are accumulated, such as heavy metals, and is particularly appropriate when slow remediation of relatively low metal concentrations is acceptable. Advantages compared with existing remediation methods include the minimal site destruction and destabilization, low environmental impact, and favourable aesthetics; advantages compared with biosorption include continuous in situ regeneration of the biomass, and the ability of living plant cells to supplement passive sorption of metals with metabolic mechanisms of metal uptake and detoxification [5-8]."

Jan 1, 2014

By Forrest T. Moyer, Nina L. Jones, Mary B. McNair, Virginia C. Berté

To keep the mineral and allied industries informed of trends in the causes of accidents, and to point out the need for corrective measures, the Bueau of Mines collects, analyzes, and periodically publishes health and safety statistics. This report includes data for 1963 on injury experience, with related employment statistics, at coal mines in the United States. These data are presented in tabular form under the following headings:

Aug 1, 1965

One Hundred Sixteenth Meeting of the Institute, Monday, Feb. 18, to Thursday, Feb. 21, inclusive, 1918. Committee on Arrangements J. E. JOHNSON, JR., Chairman BRADLEY STOUGHTON, Vice-Chairman A. R. LEDOUX J. V. N. DORR L. W. FRANCIS F. T. RUBIDGE G. D. VAN ARSDALE MRS. S. J. JENNINGS E. M. SHIPP RALPH W. DEACON ARTHUR L. WALKER The program for the New York Meeting, in February, 1918, as planned by the Committee on Arrangements at meetings in the middle of December, and therefore subject to slight alteration in detail, is as follows: MONDAY, FEBRUARY 18 9 a. m. to 5 p. m. Registration at Institute Headquarters. 10 a. In. Technical Sessions. 12.30 p. in. Luncheon at Engineering Societies' Building. 2 p. m. : Technical Sessions. 8.30 p. m. War Smoker or Patriotic Meeting. TUESDAY, FEBRUARY 19 10 a.m. Annual Business Meeting, followed by Technical Sessions.

Jan 1, 1918

New York Meets first Wednesday after first Tuesday of each month. J. E. JOHNSON, JR., Chairman. EDGAR RICHARD, Vice-Chairman. D. M. LIDDELL, Secretary, 7 Wall St., New York, N. Y. C. A. BOHN, Treasurer. JOHN V. N. DORR, LEWIS W. FRANCIS. Boston Meets first Monday of each winter month. R. L. AGASSIZ, Chairman. JAMES G. CARLETON, Vice-Chairman. E. E. BUGBEE, Secretary-Treasurer, Mass. Inst. of Technology, Cambridge, Mass., W. E. C. EUSTIS. G. A. PACKARD. Columbia Holds four sessions during year. Annual meeting n September or October. W. H. LINNEY, Chairman. OSCAR LACHMUND, Vice-Chairman. LYNDON K. ARMSTRONG, Secretary-Treasurer, P. O. Drawer 2154, Spokane, Wash. STANLY A. EASTON, S. SHEDD. Puget Sound Meets second Saturday of each month SIMON H. ASH, Chairman. I. F. LAUCKS, Vice-Chairman. CHARLES SIMENSTAD, Secretary-Treasurer, 425 Lyon Bldg., Seattle, Wash. GLENVILLE A. COLLINS, JOHN N. POTT

Jan 7, 1917

By J. B. Coher, M. B. Bever

COLD work destroys long-range order, as was first observed by Dehlinger and Graf.1 Dahl2 showed that the mechanical disordering caused by cold work produces changes in those properties that are affected by long-range order. The existence of order has a marked effect on tile manner in which an alloy deforms and therefore on its mechanical properties.L' The relation between order and deformation behavior however, is only beginning to be understood. Seemann and G1ander4 suggested that cold work reduces an ordered alloy to a kind of gruel of antiphase domains. According to Cottrell,5 superdis-locations and pairs of dislocations in a slip plane connected by a strip of anti-phase domain boundary provide deformation mechanisms which do not change the state of order. In general, however, slip may be expected to produce new domain boundaries and destroy order if dislocations move on intersecting planes or cut through existing domain boundaries. The yield strength of an ordered alloy may pass through a maximum with decreasing domain size.5"7 The reduction of domain size resulting from cold work may, therefore, lead to a maximum in strength properties. Flinn8 suggests that dislocations can climb by short-range diffusion during deformation and thus can generate domain boundaries not only on slip planes, but also on other planes which will be those with the lowest domain-boundary energy. It has long been known that the rate of strain hardening of an alloy in the ordered state is larger than in the disordered state.3'9 Also the slip bands in ordered CU3, AU10 and Ni3Mn" are finer than in the disordered alloys. The stress which causes initial yielding in Cu,Au passes through a maximum with decreasing domain size.6'12 A maximum has also been observed in the hardness of ordered Ni3Mn as a function of strain.' These observations suggest, but do not prove, that domain size reduction occurs during deformation. According to Fisher13 slip destroys short-range order and thus the strength of an alloy is related to the degree of short-range order present. Rudman and Averbach14 and Averbach et a1.,15 demonstrated that cold work reduces short-range order in copper-gold and gold-silver alloys. Destruction of long-range and short-range order by cold work implies slip on an appreciable fraction of planes. Yielding of an alloy in which short-range order exists or antiphase domain boundaries are present should be discontinuous because the first dislocations moving across the slip plane meet with the largest resistance.5 Such discontinuous yielding has been observed in CU3AU6,16 and Cuzn.l7 This phenomenon, however, can also be explained by mechanisms not involving order.b The published investigations of the effects of cold work on alloys with long-range or short-range order have not been covered thoroughly in reviews of order-disorder phenomena. These investigations, therefore, will be listed here. They have been concerned with strength properties> 2,3,6,8,9,12,16-21 electrical resistivity,2,4,18,19,21-26: thermoelectric power, magnetic properties,2,18,21,26 and X-ray strain'1,2,14,15,27,28 The slip systems and the appearance of the microstructure after deformation in ordered and disordered alloys have also been investigated. 6.10.ll,l7,23,29,30 The alloys used in these investigations were copper-gold. 1-4,6,9,10,14,16,18 23-26,28,29 copper-zinc. L7. 19. 20,30 nickel-manganese,2 11,21 iron-aluminum. iron-nickel,' copper palladium,4,18,22 gold-silver.4,18,22 and palladium-silver-copper.4 In the work reported here. the changes in properties of polycrystalline Cu3Au were investigated as functions of strain in wire drawing and rolling. Specimens were heat treated before deformation

Jan 1, 1961

Reviewer: P.R. Janisch The progress of mining and metallurgy in Australia and their contribution to that nation's economy closely parallel those of South Africa. Australia's was the second of the three great gold rushes of the nineteenth century. It was centred on Bendigo and Ballarat in Victoria, and occurred in the 1850's, a few years after California's forty-niners. The California goldfield also gave birth to the now common term for a tabular gold bearing deposit-a 'reef'. Amongst the fortune-seekers were sailors who had jumped ship on hearing of the riches to be found on land. When the gold ran out, and with it the money, the sailors found themselves stuck on a reef'. But others, more canny, had accumulated the means to move on, and some came to the Transvaal on the news of the Barberton discoveries. One of them was George Harrison.

Jan 1, 1993

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who registered at Institute headquarters during the period Oct. to Nov. 10, 1915: Lester S. Thompson, New York, N. Y. Arthur L. Sweetser, Boston, Mass. William Reed, El Oro, Mexico. Dorsey A. Lyon, Salt Lake City, Utah Heinrich Ries, Ithaca, N. Y. D. W. Blaylock has resigned his position with the St. Joseph Lead Co., Bonne Terre, Mo., and has accepted the position of division engineer for the Big Creek Coal Co., of Chicago, at Harrisburg, Ill. R. B. Lamb announces the removal of his office to Room 1809, 43 Exchange Place, New York, N. Y. C. C. Sanders has taken a bond and lease on the Red Mountain group of 34 mining claims (copper), Patagonia, Ariz., and has commenced extensive development.

Jan 12, 1915

PENNSYLVANIA ANTHRACITE SECTION Executive Committee R. V. NORRIS, Chairman. CHARLES F. HUBER, Vice-Chairman, W. J. RICHARDS, Vice-Chairman, EDWIN LUDLOW, Vice-Chairman, ARTHUR H. STORRS, Vice-Chairman. CHARLES ENZIAN, Secretary-Treasurer, U. S. Bureau of Mines, Wilkes-Barre, Pa. DOUGLAS BUNTING, FRANK A. HILL, ALBERT B. JESSUP, RUFUS J. FOSTER, JOHN M. HUMPHREY, ROBERT A. QUIN. The Pennsylvania Anthracite Section held its second regular meeting at the Pottsville Club House, Pottsville, Pa., July 25,1914. The meeting was attended by more than 90 members and guests. Vice-Chairman W. J. Richards presided. Following an informal dinner, W. G. Whildin, Mining Superintendent, Lehigh Coal & Navigation Co., Lansford, Pa., presented a. paper on Steep Pitch Mining of Thick Coal Seams, illustrated by numerous drawings. This paper will be printed in the November number of the Bulletin. A lively discussion followed the reading of the paper.

Jan 10, 1914

PERSONAL (Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who registered at Institute headquarters during the period June 10 to July 10: J. C. Ralston, Spokane, Wash. E. P. Ashmore, So. Porcupine, Ont., Can. William H. Yeandle, Jr., Mexico City, Stuart Croasdale, Denver, Colo. Mexico. W. E. Hopper, Houghton, Mich. W. C. Minsch, Mexico City, Mexico. D. W. Brunton, Denver, Colo. H. V. Winchell, Minneapolis, Minn. Fred Crabtree, Pittsburg, Pa. W. G. Swart, Denver, Colo. Robert S. Lewis, Salt Lake City, Utah. D. F. Schindler, Madison, Wis. Noel Cunningham, Timmins, Ont., Can E. R. Pettebone has just been elected a Trustee of the Pennsylvania State College, being supported by the votes of the delegates of the Pennsylvania Anthracite Local Section of the Institute and the Engineers' Society of Northeastern Pennsylvania.

Jan 8, 1914

By Carolina Machado de Castro Amaral

A necessidade de treinamento é uma realidade nas indústrias. A qualificação de operadores é importante para garantir segurança e prevenir perdas econômicas. Nesse contexto, o objetivo desse trabalho é desenvolver e avaliar um simulador de treinamento de operador. O estudo de caso é um moinho vertical, comumente utilizado na indústria de cimento. Nessa direção, passou-se pela construção de um supervisório, pela modelagem e simulação dinâmica de um moinho vertical e, por fim, pela elaboração e execução de um treinamento. Para tal, foram construídos três cenários de situações anormais, além da consideração da operação normal. Ainda em relação à metodologia, treinaram-se dois grupos de alunos com métodos distintos de ensino: o primeiro recebeu apenas um treinamento teórico, através de uma apresentação multimídia; e o segundo, após esse treinamento teórico, recebeu um treinamento prático, ou seja, do tipo aprender fazendo, a partir do contato direto com o simulador de processos. De modo geral, percebeu-se que o contato com a prática possibilitou um maior entendimento da operação do moinho vertical, do grau de dependência entre as variáveis de entrada e de saída, e das variáveis utilizadas para a recuperação do processo à operação normal, contribuindo ainda para uma maior fixação do conhecimento teórico. Esse trabalho é resultado de uma parceria UniversidadeEmpresa, cujas atividades foram desenvolvidas por um grupo de alunos de graduação em Engenharia Química.

Aug 17, 2017

By Pedro Henrique Moura Costa

Com o estudo realizado em artigos técnicos e acadêmicos e vivência no ramo industrial, ficou evidente uma deficiência no desempenho dos sistemas de controle regulatório das plantas industriais. Parte dessa deficiência é proveniente da falta de engenheiros de controle para auditar as malhas de controle regulatório. Foi realizado em um forno de tratamento térmico, um trabalho de auditoria das malhas de controle regulatório, baseando-se em uma metodologia já existente na literatura. Levantou-se informações do processo do forno como, os controladores automáticos, o sistema de aquisição de dados e a infraestrutura de rede de automação e por seguinte, as implementações dos PID's no CLP. Após essa contextualização, métricas para avaliar o desempenho inicial das malhas foram utilizadas e então, o funcionamento dos elementos de controle utilizados no forno foram diagnosticados através de ferramental estatístico e análise dos sinais na ferramenta PIMS. Adquirido o conhecimento necessário sobre o processo e o diagnosticado de maneira concisa, ações corretivas e de otimização foram realizadas e propostas com o intuito de otimizar o desempenho das malhas de controle. Por fim, os índices de desempenho do sistema são recalculados e os valores comparados com os valores pré auditoria, concluindo que pode ser possível melhorar alguns dos principais termos adotados no negócio como redução de custos, aumento de produtividade e sustentabilidade.

Jul 30, 2018

By Cícero Alberto Pereira Belém

Neste artigo, buscou-se replicar, em laboratório, os procedimentos de retificação do eixo propulsor, elemento responsável pela transmissão de força e potência para os hélices do Navio, e que, frequentemente, apresentam problemas de desgaste devido ao atrito entre o eixo e seus pontos de apoio (mancais). Em virtude do intenso uso deste tipo de transporte, é frequente a manutenção da linha de eixo dessas embarcações, havendo a necessidade de uma análise que verifique se os métodos utilizados seguem padrões normatizados e que passem por testes de qualificação. A relevância regional do estudo se justifica pelo potencial hidrográfico da Região Amazônica, a qual possui bacias como Solimões-Amazonas e Rio Madeira, que servem como vias de acesso e de transporte de pequenas, médias e grandes embarcações; seus afluentes são verdadeiras estradas fluviais, sendo um modal hidroviário de importância histórica e cultural. As operações em laboratório seguiram as etapas: soldagem dos Corpos de Prova pelos processos SMAW (processo mais utilizado na maioria das empresas de retificação de eixos na região Norte) e GMAW com dois métodos (automatizado e manual) e com adição de dois metais de solda diferentes (307, 309L com e sem adição de Nióbio); ensaio por Líquido Penetrante (LP), Metalografia, Análise Macrográfica e Micrográfica e Análise de Microdureza. Os resultados obtidos em laboratório demonstraram que a metodologia desenvolvida na retificação é apropriada e eficiente para a recuperação de eixos propulsores.

Oct 30, 2017

By Peter Moser, Thoma Oberndorfer

"Within the research project “Mine Development” (Fettweis and Moser, 1990) a PC-based mine database has been built up since 1991 and so far includes detailed technical and economic data of about 150 under-ground hardrock mines in industrialized countries worldwide. These data represent about 50% of the underground hardrock mines in west and central Europe, Scandinavia, United States, Canada and Australia (Fig. 1). The mining operations included in the database have been visited directly and analyzed with respect to their deposit conditions, their general design and layout and also their operational and economic performance.The main aim of the Mine Database is to make a contribution to an improved planning of new underground hardrock mines. An analysis of current mine planning practices shows, that both personnel and company experience is still a dominant factor in planning new underground hardrock operations. Through the information included in the Mine Database the experience of a single per-son or company is supplemented by the experience of a wider group of people. The Mine Database makes the huge amount of experience that is available worldwide in the field of under-ground mining accessible for new mining projects. From that a contribution to a more reliable mine planning procedure based on the performance of existing mining operations is expected.In addition to its use in planning new mining operations, the Mine Database can con-tribute to the exchange of technical data among different mining operations, especially on equipment performance, etc. Such an information service is offered by the Department of Mining Engineering & Mineral Economics in Leoben and is already being used by different mining companies. To respect proprietory information, company specific information is not released under any circumstances.The cost of building up the Mine Database, so far, is about US$500.000 — two thirds of which is labour, and one third, travel."

Jan 1, 1996

By Andrzej Luszczkiewicz, Magdalena Duchnowska, KGHM Polska Miedz S. A., Witold Pawlos, Jan Drzymala, Alicja Bakalarz, Przemyslaw B. Kowalczuk

A pre-flotation process of the Kupferschiefer ore with only frothers produces a concentrate enriched in carbonaceous matter and tailings for further upgrading steps. A partial removal of easy-to-float components of the feed before the main enrichments steps by flotation (rougher, scavenger) improves overall efficiency of separation of valuable elements from the ore. Since the types and doses of frother used for pre-flotation effect the process, the aim of this study was to determine the influence of selected frothers on the efficiency and selectivity of the Kupferschiefer ore processed by KGHM Polska Miedz S.A. A series of pre-flotation tests in the presence of different poly(propylene glycols) ethers, poly(ethylene glycols) ethers and aliphatic alcohols were conducted. The obtained results indicated that the types and doses of frother determine the flotation selectivity of copper and total organic carbon. The evaluation of the pre-flotation process was based on the analysis of selectivity parameters calculated from the recoveryrecovery Fuerstenau upgrading curves as well as the values of copper and organic carbon grades in the flotation products. It was shown that pre-flotation performed in the laboratory scale using a suitable frother provides higher overall flotation selectivity of organic carbon with lower overall flotation recovery of copper in comparison to flotation without the pre-flotation step. Thus, the pre-flotation process improves the quality and quantity of the final concentrates produced from the Kupferschiefer ore.

Jan 1, 2016

By Lucas Travi

Os problemas gerados no processamento do aço inoxidável AISI 316 são um grande problema do setor metal mecânico, por exemplo, no processo de usinagem, onde o material sofre altas taxas de deformação plástica e elevadas temperaturas na região de contato ferramenta-peça. Além disso, a adesão de aço inoxidável em materiais de maior dureza, no caso a ferramenta, também são problemas enfrentados. Neste trabalho foi feito um estudo qualitativo em escala laboratorial do contato entre um material de maior dureza (aço AISI M2 nitretado a plasma) e o aço AISI 316. Foram realizados ensaios de microdureza Vickers e rugosidade afim de caracterizar as amostras de aço AISI M2. Ensaios tribológicos do tipo Ball-on-Plate foram realizados com a finalidade de determinar o coeficiente de atrito ao longo do tempo para os pares tribológicos formados. Análises feitas via MEV/EDS foram feitas tanto nas trilhas geradas nas superfícies das amostras quanto nas esferas, para detectar pontos de adesão, deformação plástica e transferência de material entre as duas superfícies. Ficou comprovado que a nitretação a plasma com gaiola catódica proporcionou um menor coeficiente de atrito ao longo do tempo quando posta em contato com a esfera de aço inoxidável, bem como foi possível observar a formação de uma menor quantidade de pontos de adesão de aço inoxidável para esta superfície.

Aug 17, 2017

By P. J. Colbassani

Samples of mine atmospheres collected by Federal coal-mine inspectors during their inspections and investigations of coal mines, in accordance with provisions of the Federal Coal Mine Safety Act (66 Stat. 692; 30 U. S. C., sees. 451-483) are analyzed routinely by chemical methods at Bureau of Mines laboratories. When samples collected in open workings of nongassy coal mines at points not less than 12 inches from the roof, face, or rib contain 0.25 percent or more methane, the act requires the operator, during operation of such mine, to comply with the provisions of sec. 209, Title II, of the act, which pertain to gassy mines. The methane con-tents of such samples are determined by a physical method based on infrared absorption spectrometry to provide an independent check on analytical results obtained by chemical methods. This information circular describes the equipment and procedures used by the Bureau for determining low concentrations of methane in coal mine atmospheres by infrared absorption spectrometry. ACKNOWLEDGMENTS The authors are indebted to Dr. R. A. Friedel, Chief of Spectrometric Section, Branch of Coal-to-Oil Research, Bureau of Mines, for suggesting the analytical method and for furnishing valuable advice and assistance, and to J. A. Queiser of his staff for making exploratory measurements by this method; to Dr. M. G. Zabetakis of the Division of Explosives Technology for his assistance during the conduct of preliminary experimentation; and to L. B. Berger, Chief, Branch of Health Research, under whose guidance the equipment was procured and the work conducted.

Jan 1, 1958

By J. E. Dutrizac

The dissolution of low-iron sphalerite, (Zn,Fe)S containing 0.08% Fe, in ferric sulphate-sulphuric acid media was investigated using closely sized fractions of crushed sphalerite crystals and sintered disks made from the crushed crystals. Linear kinetics are observed, and the predominant reaction products are ZnSO4, FeSO4 and elemental sulphur. The leaching rate increases systematically with increasing temperature, and the calculated apparent activation energy is 56 kJ/mol for the sized sphalerite and 54 kJ/mol for the sintered disks. The relatively high apparent activation energy suggests that the rate is chemically controlled, a conclusion supported by the insensitivity of the rate to the disk rotation speed. The rate increases as the 0.22 power of the Fe(SO4)1.5 concentration, and as the 0.22 power of the H2SO4 concentration. However, in the absence of ferric ions, the rate increases more significantly with increasing H2SO4 concentrations, and relatively rapid rates are observed in solutions containing >0.5 M H2SO4. In 0.1 M Fe(SO4)1.5-0.3 M H2SO4 media, the measured rate decreases with increasing sulphate concentrations, added as Li2SO4. The rate of dissolution of low-iron sphalerite is promoted by dissolved copper concentrations as high as 800 mg/L. In contrast, dissolved silver, even in the 0-2 mg/L concentration range, significantly retards the dissolution of the low-iron sphalerite.

Jan 1, 2008

THE morning session on non-metallic minerals was opened briefly by the chairman, Oliver Bowles, giving the usual instructions and then turning immediately to the introduction of the speakers. "Min-ing and Preparation of the St. Peter Sandstone in' Arkansas" by D. D. Dunkin was first presented by W. M. Weigel, mining technologist for the Missouri Pacific R. R. The paper covered a discussion of the geology of the sandstone, correlating it with the sand-stones at Klondike, Mo., and at Ottawa, III. Its physical appearance, structural characteristics and thickness; the mining methods, blasting, loading, haulage and classification were taken up. A series of slides aided in clarifying the details. The discussion consisted of questioning Mr. Weigel on operating details. The second paper, "Geology and Mining of Diaspore and Flint Fire-Clays of Missouri," written by H. S. McQueen, geologist with the Missouri Bureau of Geology and Mines, and C. R. Forbes, professor of mining, Missouri School of Mines and Metallurgy, was presented by Mr. Forbes. It thoroughly covered the geology, stressing the peculiar sink formations in which all diaspore clay deposits of the region occur. The crudeness of the mining methods was mentioned and believed justifiable because of the small size of the indi-vidual deposits. It was stated that the diaspore and flint clay deposits of Missouri were confined to an area 60 mi. square and it was found in a survey that the average deposit had dimensions comparable to the fol-lowing: 100 ft. long, 75 ft. wide and 50 ft. deep. The largest deposit found was 800 ft. long. 500 ft. wide and 20 ft. deep. It is estimated that the known reserve of clays is from 750.000 to 1,500,000 tons. Mr. Forbes stressed the fact that in mining clays the major problem is entirely one of sorting. This is done under the supervision of a pit foreman trained to make this classification by eye. The mine-run clays are sepa-rated into diaspore clay ranging in alumina content from 70 to about 85 per cent, first grade Burly clay 00 to 70 per cent, and Flint clay 52 to 60 per cent. Discussion of the paper consisted in questioning Pro-fessor Forbes on labor. cost, haulage, drilling, and geology.

Jan 3, 1928

By R. P. King

Held on the 22nd March 1972 at Kelvin House. Four papers were presented at this colloquium, which was attended by approximately 120 people. The first paper, 'Flotation Research Work at the N.I.M. research group, University of Natal on the modelling of a Flotation Process' was presented by Dr R. P. King, the leader of the N.I.M. Research Group in the Department of Chemical Engineering at the University of Natal. A discussion panel, under the chairmanship of Dr R. E. Robinson with Mr M. Dawson (PMC), Mr E. Roux (FOSKOR), and Dr B. K. Loveday (NIM), discussed the potential application of the theoretical work on flotation modelling to industrial processes, and alternative approaches to providing a way of control of flotation plants. The second paper, 'Fundamental Studies of the Flotation Process the Work of the National Institute) for Metallurgy', was presented by Dr N. P. Finkelstein. The discussion panel for this paper was under the chairmanship of Professor D. D. Howat,and had as its members Mr H. P. Carlisle (JCI), Professor D. le Roux (University of Pretoria), and Mr E. Rudolph (Anglo American Research Laboratories). A lively discussion on this paper ensued, with several contributions from the floor. After lunch, Mr S. K. de Kok, Assistant Consulting Metallurgist, Anglo Vaal, presented a paper on 'The Flotation of Copper and Zinc Sulphide from Prieska Ore'. The paper was discussed by a panel comprising Dr V. C. Lovell (NIM), Mr A. Gilbert (General Mining), and Dr D. Legge (Anglo Vaal), under the chairmanship of Dr L. Bushell. This discussion, in which many members of the audience participated, revolved around the difficulties associated with the production of copper and zinc concentrates and the lack of fundamental information on the behaviour of copper and zinc sulphides in flotation. The final presentati0n was a paper, 'The Recovery by Flotation of Cassiterite contained in Gravity Concentration Plant Tailings', presented by Mr E. B. Viljoen (Metallurgy Department, Goldfields South Africa Limited). The discussion, led by a panel consisting of Mr O. Tant (Goldfields Laboratories), Mr J. Levin (NIM), and Mr R. I. Shanks (NIM), under the chairmanship of Mr H. Cross (Goldfields South Africa Limited) referred particularly to the use of new reagents for the flotation of tin, with particular emphasis on the fundamental relationship between reagent composition and its ability to float this type of mineral.

Jan 4, 1972

By Douglas H. Silvey

"The historical transformations in fire -resistant conveyor belt compositions in the past 20 years have been influenced by factors of material cost, changing flame and burn test requirements, material replacements, adhesion and oil resistance considerations, increased responsibility and legal liability. Specifically, this has resulted in a swing from neoprene-cotton belts to S.B.R. blends and synthetic fibre carcasses, and tighter quality control and documentation of test data.Flame dynamics are discussed and the function and performance of the multiple types of flame-resistant additives in the flame front are presented. Specific flame and burn test requirements are described. The belt manufacturers' requirements and criteria in selecting the types of flame-resistant additives are presented.The author will describe the composition of the types of flame-resistant compounds used in a practical production, the belts that are available on today's mark et and future developments in requirements that may further transform the composition of fire-resistant belts.IntroductionThe historical transformations of conveyor belt compositions in the past two decades have been based on factors common to those leading to changes in man y organic compositional products. These factors are material cost, new materials, the customer' s changing requirements, government regulation s and increased manufacturer' s liability.As a basis for understanding the product, I will provide a brief breakdown of the conveyor belt composite. Figure 1 represents a cross section of a typical belt. A skim rubber coats each fabric ply of the belt carcass and is of a different rubber composition than the outside layer of rubber which forms the cover. This outside cover layer is designed to protect the belt from environmental factors such as heat, oil and abrasion, and other factors involved in the service condition s under which the belt will operate. In the case of fire-retardant belt s, both the skim coat encapsulating the fabric plies and the outer cover must contain sufficient fire retardancy to overcome the contribution to burning of the decomosition products of the fabric."

Jan 1, 1982