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By Paul A. Beck

IN several recent investigations1 ' considerable evidence was accumulated to show the predominance in various face-centered cubic metals of a certain relative orientation, corresponding to a rotation of 30" to, 40" around a [111] axis, between a matrix with a strong single orientation texture and grains growing in this matrix." This relative orientation was found to occur both in recrystallization and in coarsening, "secondary recrystallization", so that one is inclined to look for an explanation applicable in both cases. The abundance of growing grains in the described orientations proves that suitable "nuclei" are present in the matrix material and that they have the capacity to grow. The scarcity of growing grains in other orientations may be explained in one 'of two ways. Either the number of nuclei or the rate of growth must decrease strongly for orientations deviating from that predominating among the growing grains, Fig. 1. Both the "oriented nucleation" and the "oriented growth" theory found support in the literature. Because the frequency of nuclei as a function of orientation is in most instances not amenable to direct experimental investigation, a definitive decision is difficult to achieve. However, it is now known with great certainty that the rate of boundary migration is strongly dependent on the relative orientation of the two grains meeting at the boundary and that the orientation favored by high boundary mobility closely corresponds to that predominating in most cases of recrystallization and coarsening. Thus, it was found that, in general, the mobility is very low for boundaries between grains of nearly identical orientation, or for coherent twin boundaries. On the other hand, the boundaries between two grains of a relative orientation correspending to a [1111 rotation of 30" to 40" have the highest mobility in face-centered cubic metals. If a large variety of nucleus orientations are produced grow- by means of a highly inhomogeneous local deformation, nuclei close to the above orientation are found to grow fastest.z4 In view of this evidence and of the fact that the preferred orientation relationship is the same in recrystallization and in coarsening, the oriented growth theory appears by far the more promising one. Since the origin of nuclei in primary recrystallization is certainly different from that in coarsening, the occurrence of the same orientation relationship in the two processes would be difficult to explain on the basis of oriented nucleation. other advantages of the oriented growth theory are its capability of accounting for the often observed sharpening of the texture in coarsening, and its suitability for explaining the role in the formation of the ''cube texture,, of the most important variables, such as the degree of rolling, the penultimate grain size, and the time and temperature of the last anneal: No similarly consistent explanation of all these effects has ever been offered in terms of oriented nucleation. An important problem in connection with the oriented growth theory is the following: In the ce-c entered system there are four [111] axes and

Jan 1, 1952

By L. L. Karafiath, S. G. Vick, E. A. Nowatzki

Computer analyses of the trafficability of copper mine tailings by four different commercially available BWEs were performed. A mathematical model incorporating the tailings' Coulomb strength parameters and the vehicles' geometry and operational characteristics was used to study the vehicle terrain interaction. The computer output provides the maximum tractive force (net drawbar pull) that each BWE can develop for given tailings conditions without bnngzng about a state of plastic failure in the tailings. Estimates of sinkage are also provided. The theoretical results for the BWEs and tailings studied compare favorably with the operating experience of similar BWEs used for remining gold tailings in South Africa. This lends some confidence to the validity of the mathematical model. The results of such analyses may be wed to evaluate, on a relative basis, which of a number of different machines would perform better than others under given conditions of a tailings deposit.

Jan 1, 1982

Your Council has pleasure in submitting its report for the year ended 30th June, 1969. COUNCIL The following served as Office Bearers during the year under review: Messrs. R. C. J. Goode (President), J. K. E. Douglas and V. C. Robinson (Vice-Presidents), P. Lambooy (Immediate Past President) and D. G. Maxwell (Honorary Treasurer). Members of Council: Messrs R. J. Adamson, M. Barcza, F. P. Bath, Or J. M. Bereza, Or W. Bleloch, Messrs H. Britten, H. E. Cross, A. R. C. Fowler, A. E. Gilfillan, G. W. Holl, Prof D. D. Howat, Or J. P. Hugo, Messrs C. J. Irving, D. M. Jamieson, J. G. Kirchner, Prof J. de V. Lambrechts, Mr C. E. Mavrocordatos, Or J. T. McIntyre, Mr J. A. Nixon, Prof R. P. Plewman, Messrs J. F. Reid, H. Simon, C. G. Sowry, W. T. Stobart and P. W. J. van Rensburg. Ten Council meetings were held during the year with an average attendance of eighteen. FINANCE The annual accounts, which are attached to this report, show an excess of expenditure over income of R2,124, compared with an excess of income over expenditure of R4,218 last year. There are a number of reasons for this substantial change. There was a loss on realization of investments compared with a substantial surplus in recent years. The publication of the Journal once again resulted in a large loss in spite of a generous subvention of R2,000 from the Department of Cultural Affairs and other assistance amounting to R750. The revenue from sales of publications was down considerably. This is a figure which fluctuates considerably from year to year. The secretarial fee was considerably higher than previously. Due to pressure of work it was necessary for the Secretary to relinquish his duties with the Institute of Land Surveyors and, therefore, for this Institute to assume the additional staff costs involved. Finally there was unusual expenditure on the 75th Anniversary celebrations. There was a pleasing increase in revenue from subscriptions, due to the steadily increasing membership, but this was quite inadequate to cover the substantial increases in expenditure and losses in revenue mentioned above. The changes that have been effected in the arrangements for the publication of the Journal have been mentioned elsewhere in this report. It is expected that these will bring about substantial financial benefits in the long term. The MacArthur Forrest Memorial Fund shows an excess of income over expenditure of Rl00 and the total fund was therefore increased by this amount to R4,206. The balance sheet indicates that the market value of quoted shares and debentures increased during the year from R8,755 to R13,059, while the Accumulated Funds now amount to R22,567 as against R24,691 last year. MEMBERSHIP Fifty-six Members, fifty-five Associate Members, thirteen Graduates, twenty-two Affiliates and twenty- nine Students were elected during the year. Twelve Members were admitted to Life Membership; seven Associate Members were transferred to the grade of Member; four Graduates and two Students were transferred to the grade of Associate Member; five Students were transferred to the grade of Graduate; three Affiliates were transferred to the grade of Member; five Affiliates were transferred to the grade of Associate Member. Three Members, seven Associate Members, two Graduates, two Affiliates and six Students were removed from the Membership Roll in terms of By-Law 7.7.1. Your Council records with deep regret the death during the year of the following members: E. F. J. Bulman (Member), E. F. Chapin (Member), R. A. H. Flugge-de-Smidt (Hon. Life Member), T. S. Haldane (Member), J. M. Massie (Associate Member), S. W. Page (Student), S. R. Rabson (Member), M. Ramsay (Member), F. Wartenweiler (Hon. Life Member). A comparative statement of the membership as at 30th June, 1969, and the end of the previous year is shown in the following tabulation: 30th June 30th June 1968 1968 Honorary Life Members 12 10 Honorary Members 6 6 Life Members 176 189 Members 488 514 Associate Members 409 448 Graduates 60 68 Affiliates153 155 Students152 162 1,456 1,552 PAPERS AND JOURNAL The Institute is changing the format of the Journal from the present size to the standard international A4 size with effect from August, 1969. In making this change it will conform to more general practice today in regard to publications and this should effect certain economies and facilitate selling of advertising space. It has been arranged that in future the publication of the Journal, including advertisement sales, will be handled by Kelvin Publications (Pty.) Ltd. who are already doing this work satisfactorily for the Mechanical and Electrical Engineering Institutes. In making these changes the opportunity was taken of redesigning the outer cover of the Journal to incorporate the new coat of arms. The Presidential Address by Mr R. C. J. Goode and twelve papers which were published in the Journal during the year are listed below: August, 1968: Presidential Address: "The Institute-In retrospect and prospect." September, 1968: "Rotary mill liner practice in the South African gold mining industry," by J. H. French and O. E. Lissner.

The thirty-ninth meeting of the Boston Section was held at the Engi- neers? Club on Monday evening, Dec. 4, 1916. Thirty-three members and guests sat down to dinner; There were present as section guests; Dr. L. D. Ricketts, and Prof. Bradley Stoughton, President and Secretary of the parent society, and each was called upon to speak. Mr. Stoughton spoke of the growth of the Institute during the past year and described the very numerous and important activities, of which the junction of the American Society of Civil Engineers with the other three societies is perhaps the most important. Dr. Ricketts, the advertised speaker of the evening, spoke on Recent Progress in Mining and Metallurgy of Copper Ores. In discussing the improvements in mining, he traced the mining methods from square- set mining to the modified Ohio System now so successfully used at Inspiration: In metallurgy, he described the growth of reverberatory-smelting ant1 allied problems such as the utilization of the waste heat for generating steam. He laid stress on the importance of sampling and bedding of

Jan 6, 1917

By Oliver C. Ralston, James E. Norman

SEPARATION of minerals by froth flotation is rightly called an art. It can truthfully be said that no two ores separate in the same way. The difference in results obtained when natural and synthetic mixtures of minerals are separated is so great that such tests frequently have been worthless in attempting to select conditions in which a natural mixture will separate. With a few rare exceptions, the natural mixture is much more difficult to treat than a synthetic mixture, and a much poorer separation is obtained. Perhaps several experimenters have wondered why 10 or 20 per cent of a mineral being floated from an ore does not float and is different from the 90 or 80 per cent that is recovered. In experimental tests on pure sphalerite, observers1 have noted that varying amounts of sphaIerite may be froth-floated with pine oil alone, the amount recovered in the froth depending apparently upon the source of the sulphide. The only explanation of results such as these, barring insufficiency of frother or time of flotation, is that the surface of the mineral floated is different from that of the mineral depressed. This difference often has been found to be caused by natural contamination of mineral surfaces, apparently brought about by weathering and exposure to natural solutions. There is virtually no rock that is absolutely unweathered. One of the writers had an exceedingly instructive experience in 1931 while working with United Verde copper-zinc iron sulphide ore in Arizona. Nonselective flotation of chalcopyrite and sphalerite away from some of the pyrite was all that could be accomplished. All known depressants produced only slight effect. Sodium cyanide showed some effect, but so much had to be used that only a small amount of chalcopyrite could be

Jan 1, 1939

By E. Orowan

LONG before the role of dislocations in the plastic deformation of crystals was recognized, the stress-strain field around dislocations received considerable attention in the theory of elasticity. It seems that Weingarten1 was the first to consider dislocations as simple and typical sources of internal stress in elastic solids, and Volterra2 and Timpe3 investigated their elastic field. Fig 3-1 shows the two basic types of dislocations considered by Volterra. The first arises by making a straight-edged .plane cut in a solid, displacing the two surfaces of the cut in their own plane relatively to one another by a constant amount in a direction perpendicular to the edge, and welding them together; this is shown in Fig 3-la, where the outer cylindrical surface represents the boundary of the solid, and the thin spiral cylinder around the edge of the cut has been removed in order to avoid infinities of stress and strain. The second type of dislocation is shown in Fig 3-lb; here the surfaces of the cut have been displaced relatively to one another by a constant amount parallel to the edge, and then welded together. After J. M. Burgers,4 these two types are called edge and screw dislocations, respectively. They represent simple limiting cases; in the general case, the surfaces of the cut are displaced by a constant vector that lies in the plane of the surface but has components both parallel and perpendicular to the edge of the cut. This vector is the Burgers or slip vector. The name “dislocation” was given by A. E. H. Love;5 it was bor-

Jan 1, 1954

By Whincup P

Hilton deposit comprises en-echelon silver-lead-zinc orebodies with reserves in excess of 50 million tonnes. The host rock to the ore is a dolomitic and pyritic shale/siltstone which dips steeply west. The shale/siltstone is deeply leached and porous, particularly over the Ore Zone where the depth of leaching continues down to 440 m below surface, and constitutes an extensive permeable aquifer system containing a large volume of saline acidic groundwater. Initial production commenced at Hilton in 1987 well below the aquifer. A dedicated dewatering and monitoring programme is in place to ensure security of stoping operations and allow extraction of ore close to the leached zone in future years. Dewatering is undertaken from controlled bores from underground sites. Mine groundwater discharge is presently at the rate of 4000 kl/day with plans to increase to 8000 kl/day. An additional 2000 kl/day of fill and service water and water from secondary aquifers is also pumped from the mine daily. Although recharge rate to the aquifer is minimal, studies indicate that due to the size of the aquifer and future extensions to mine development, dewatering will be a life of mine activity. The investigations which have been undertaken to determine optimum dewatering techniques and schedules are described. These include production bore tests, mine planning constraints and computer aquifer modelling. Gravity geophysical techniques have been successful in delineating the lateral and vertical disposition of the aquifer. The mine dewatering schedule, whose principal component is underground mine drainage, is also outlined.

Jan 1, 1988

By August Wendel

weight, and deflection, and recommends that the Pennsylvania Railroad Company denland that rails be made on specifications, based on these six variables, so narrow, that to fill them would cause the constant rejection of enormous quantities of steel, and a consequent enhancement of the price of rails, probably ten or twenty per cent., without any certainty that such rails would be any better than those the steel-mills are now making. I earnestly hope that the investigation which Dr. Dudley has so ably carried on will be continued. I hope the Pennsylvarlia Sailroad Company, or preferably a combination of several railroads, will institute the prolonged investigation which I think will be necessary to solve this deep problem; that they will take a hundred or more rails, watching and noting down carefully every detail of their manufacture as well as their analysis; that they will be carefully weighed before, during, and after service; that their crop-ends will be tested before service, and the rails themselves after removal; that all the sources of error which Dr. Dudley admits in the present investigation may be removed, and that enough facts may be gathered and tabulated so that the conclusions which may be drawn from them may be apparent to every one without labored discussion or heated argument. But I venture to prophesy that after this investigation shall have been completed, and a formula adopted which shall be satiefactory to both manufacturers and consumcrs, that formula will not be the one now under discussion. I hope Dr. Durlley will pardon me if I have been unduly severe in my criticism, and consider that I have written my remarks hastily and at a time which should have been given to needed rest. I differ with him only as regards the conclusions which he has drawn. I appreciate the value of his labors, and only make public my own conclusions in the hope of contributing to the advancement of the science of steelmaking, in which we are ail so deeply interested. Dr. August WENDEL, Troy, K. Y.: Dr. Dudley's last paper gives, certainly, very valuable and interesting information regarding the wear of rails under different conditions. His results concernillg the composition of rails, explotle, rather startlingly, some old theories regarding the wear of rails, and 1 think after his formula is silnplified it will be one good formula to work by. As he now arrives at the same conclusions reached ill his first paper, some of my remarks will apply to both, althougl~ I would

Jan 1, 1881

By H. R. Hanley

IT is a well-known fact that the solubility of zinc compounds decreases when these compounds are roasted in contact with iron compounds, but descriptions of tests to quantitatively express the fact have not appeared in the literature. Possibly such an expression cannot be uniformly and exactly duplicated by different operators because of the variation in the personal equation. In a general way, however, the reactions between zinc compounds and iron compounds under roasting conditions will show a certain trend with changing conditions and the approximate quantitative expression of this trend appears reasonably well established by experimental work conducted for this purpose.

Jan 1, 1929

By Pedro Damas Resende

As propriedades físicas e mecânicas de ligas NiTi são fortemente influenciadas pelo seu histórico termomecânico. Este trabalho visa avaliar a influência de uma deformação preliminar (chegando ao escorregamento da martensita) aliada ao recozimento de uma liga NiTi sobre suas propriedades através de DSC (Calorimetria Diferencial Exploratória), ensaios de tração até a ruptura e difração de raios X (DRX). Observou-se um aumento da histerese térmica como resultados dos tratamentos, e as transformações martensíticas passaram a ocorrer com formação de fase intermediária (fase R) para os grupos recozidos. Os valores de tensões de início e fim de patamar do grupo tratado diminuíram em relação ao grupo do material como recebido.

Aug 16, 2017

By L. D. Muller, C. P. Sayles

When minerals are mined in arid or semiarid areas where water is at a premium, dry processing is a natural route to take for concentrating or classifying the values. Until recently though, dry processing technique were limited by the lack of suitable equipment. With the advent of the pneumatic pinched sluice at Warren Spring Laboratory, Stevenage, Hertfordshire, England, a new tool emerged to fill this gap and it has the potential of providing industry with a high output concentrator or preconcentrator for dry natural ores and secondary materials. The pneumatic pinched sluice gives every indication of fulfilling these requirements with the added advantage that with homogeneous materials-such as crushed limestone or quartzose sands-it may alternatively operate as a high throughput dry classifier or sizing device. An industrial version of the equipment is now being manufactured by Dryflow Separators Ltd., as sole licensee for the National Re- search Development Corporation.

Jan 1, 1971

The Mt Todd Project is located 42 km northwest of Katherine in the Northern Territory. The identified mineral resource estimate for the Batman gold deposit is 66.7 million tonnes (Mt) grading 1.4 grams/tonne (g/t). Proved and Probable Ore Reserves total 42.3 Mt grading 1.5 g/t. Orebody definition and reserve estimation is based on extensive percussion and diamond drilling. Exhaustive bias analysis comparing grades produced from different drilling techniques has been undertaken. Similarly, detailed check assaying programs have been run to validate grade data produced by commercial laboratories used during the exploratory drilling phase. Significant biases were established from both studies and appropriate 'corrections' were made to drillhole databases prior to final resource and reserve estimation. 3D geostatistical modelling has been utilised for resource and reserve estimation, with specialist consultants contracted for this work. At all times, interpreted geological controls on mineralisation, provided by

Jan 1, 1994

By Anderson Nogueira Vidal

Os tubos de Plástico Reforçado com Fibras de Vidro, também conhecidos como tubos de PRFV são pouco utilizados em obras de infraestrutura no Brasil, principalmente por desconhecimento técnico da sua vida estrutural. Este trabalho tem como objetivo verificar a expectativa mínima de 50 (cinquenta) anos de utilização dos tubos de PRFV. A metodologia adotada consiste na realização de ensaios mecânicos de longa duração em corpos de prova de tubos de PRFV por mais de 10.000 horas (1,4 anos), conforme rigor da norma ASTM D 2992 – Procedimento B. Este ensaio é comumente conhecido como ensaio de HDB (Hydrostatic Design Basis). Os resultados mostraram que a metodologia utilizada é adequada para verificar e certificar a vida estrutural dos tubos de PRFV, bem como evidenciou que o valor de HDB encontrado é satisfatório e compatível, quando comparado aos outros ensaios de HDB realizados no mundo em tubos de PRFV fabricados pelo mesmo processo produtivo de enrolamento contínuo.

Aug 8, 2018

By Will L. Clark

He who enters a mining claim within an Indian reservation of the United States of America acquires no rights thereby, because of the fact that the lands within such Indian reservation are not a part of the public domain, and cannot be located or acquired as mineral land. However, where such an entry is authorized as to a particular reservation by an Act of Congress, such claims as may be ontered under such authorization are thereby segregated from the reservation, and the Indian title is oxtinguished. Under the Choctaw Constitution, any citizen of that nation, in other words any Choctaw Indian, who discovered a coal mine, acquired an exclusive right to all coal within a radius of 1 mile. The laws of the Chickasaw nation provided for the formation of corporations to develop coal and other mines, with authority to contract with others to develop and work the mines. Under these laws, leases were made; but Congress subsequently abrogated all existing leases, prohibited all persons from receiving royaltics from such mines, and provided that all coal within the nation should remain the common property of the tribes. , Such leases are now expressly prohibited by an Act of Congress (32 United States Statutes at Large, 655). All leases of mineral lands upon Indian reservations must now be made under regulations promulgated by the Secretary of the Interior, and the royalties must' be paid into the United States Treasury for the benefit of the tribes. In Canada the Indians have no rights to the royal mines and minerals, and the government can make no stipulation with the Indians which would affect the rights of the Province in which the lands are situated. Therefore, while it is true that under our present law no rights can be acquired to a mining claim within an Indian reservation, it seems to be fully within the authority of Congress to make laws, giving such rights to mineral locators as it may deem necessary or expedient. There is a demand for a general law that will permit mining upon Indian reservations, and I am informed that most of the members of both houses of Congress from the Western States are in favor of Congress pass-

Jan 1, 1915

By A. S. Moghaddam

The transportation of cemented and non-cemented mine tailings in the form of paste through pipelines is one of the main stages of paste backfill operations. For the purpose of pipeline design, the rheological properties of the materials, such as yield stress and viscosity must be determined. In this study, the yield stress of two Canadian mine tailings, for gold and copper mineralization, were studied using the vane method and slump tests. The comparison between the vane method and the slump tests indicates that the slump tests generally overestimate the yield stress values for both cemented and non-cemented paste backfills. In addition, the effects of 5% Portland cement (type 10) and mixing time on the yield stress of paste backfills were investigated. The percentage of cement as a binder agent has a direct effect on the increase of the yield stress of paste backfills. Yield stress measurements show that mixing times of 4 minutes and 12 minutes have the same effect on the yield stress values.

May 1, 2007

By A. R. Gregory, A. L. Podio, K. E. Gray

Dynamic elastic properties of dry and water-saturated Green River shale samples were computed from compressional- and shear-wave velocity measurements. P- and 5-wave velocity measurements were made in three mutually perpendicular directions with respect to the bedding planes. Measurements were also made in several different directions by varying the angle between the bedding planes and the direction of propagation of the wave for angles of 0, 30, 45, 60 and 909 The oriented samples were subjected to both confining pressure and axial loads, in excess of the confining stress, in the direction of propagation. In general, P- and S-wave velocities increased with increasing stress levels, with a corresponding increase in Young's modulus. Water saturation caused the P-wave velocity to increase and the S-wave velocity to decrease. Elastic moduli decreased upon saturation, except for Pois son's ratio, which increased, indicating some degree of weakening of the material. The samples showed a moderate degree of anisotropy; this was to be expected from the laminated nature and shallow occurrence of Green River shale. INTRODUCTION This paper presents some results of an experimental determination of the elastic coefficients of anisotropic materials (in particular, finely layered rocks and minerals such as Green River shale) from measurements of dilatational and shear-ultrasonic-wave velocities. Ultrasonic techniques have been used extensively in nondestructive testing. Several methods have been proposed by Mcskimmin, 1 and some of these have been used successfully to measure ultrasonic velocities in rocks. Hughes and Cross, 2 Wyllie et al., 3 and Birch 4,5 developed pulse first-arrival techniques for the measurement of dilatational and shear velocities. Williams and Lamb 6 used the method of cancellation of a traveling wave, which was later modified by Myers et al.' and perfected by McSkimmin. 8 Although this method is highly accurate, it has not been used as widely as the pulse-transmission methods recently reported by Jamieson and Hoskins 9 King,10 and Mattaboni and Schreiber. 11 It has been common practice to use some form of crystal transducers, either quartz or ceramic, that has been cut or polarized in different directions in order to generate either compressional or shear waves. However, accurate determination of shear wave velocities has been difficult due to problems that arise in obtaining a pure shear wave from cross-polarized crystals, which usually also generate a small amount of compressional energy. As reported by Gregory, 12 this energy can be seen as a long precursor preceding the sharp break of the shear first arrival. The need for generating pure shear waves led to interest in mode-conversion techniques, which are based upon conversion of the mode of vibration through wave reflection or refraction at a discontinuity. Arenberg13 showed that for certain materials and for certain angles of incidence it is possible to generate pure shear modes by reflection at a boundary. Jamieson and Hoskins 9 used a pyrex glass-air interface for generating pure shear waves, and King 10 used this method successfully for measuring shear-wave velocities in rocks. Gregory l4 arrived at a similar result by refraction of a wave at an aluminum-oil interface. A plane compressional wave, traveling in the oil phase, is incident on the aluminum at an angle larger than the critical angle for compressional waves, and thereby generates a purely transverse, plane-polarized wave in the aluminum. During the last few years methods have been developed that allow the simultaneous determination of shear and compressional velocities in solids.

Jan 1, 1969

By Fernanda Santos da Luz

Desde o período Neolítico, a argila é usada na produção de materiais para construção. Posteriormente, verificou-se que queima da argila em fornos aumentava a resistência do material, permitindo seu uso na maioria das formas abrasivas. Com a melhoria das propriedades, a cerâmica vermelha encontrou várias aplicações tais como, telhas, tijolos, louças e revestimentos. Na região estudada, a noroeste do Rio de Janeiro e a área leste da zona da mata mineira, as telhas produzidas e comercializadas exibem características correspondentes à argila local e ao método de queima. Neste trabalho foi avaliada a qualidade das telhas na região, referente às características geométricas, físicas e mecânicas, padronizadas pela norma NBR 15310:2009. De acordo com a análise dos resultados, concluiu-se que a tendência da qualidade das telhas existentes no mercado não atende aos parâmetros atuais da norma brasileira. O teste geométrico apresentou o maior número de não conformidades. A planicidade da superfície e os testes de rendimento também apresentaram desvios maiores em relação ao padrão aceitável. As não conformidades encontradas nas amostras indicaram que ocorreram falhas nos controles de fabricação do produto e na aprovação do lote que liberou o material para a produção de fábrica, resultando em produtos sem padronização.

Oct 30, 2017

By R. Els Ellis

Enhanced granulation of UASB granules was tested on pilot scale with two different test reactors (about 5 litres capacity each). Sludge from a local sewage works was used, with peach cannery effluent as carbon source. Cyclic motion of the reactor contents, and a daily replenishment of feed material create the necessary stress conditions for enhanced growth. Sizable granules, bigger than 0.5 mm, were produced within 20 days. Of the two reactors tested, the reactor equipped with a horizontal agitation shaft proved more effective.

Jan 1, 2003

By Bowmaker MD

Zinc and lead sulphide flotation con centrates containing from 0.02 to 0.20% Cd are roasted on an updraught sinter machine at the Cockle Creek Works of Sulphide Corp- oration Pty. Limited to provide sinter for simultaneous smelting of zinc and lead in an Imperial Smelting Furnace (I.S.F.). The major portion (about 85%) of cad- mium in concentrate feed to the Sinter Plant is eliminated with sinter fume and is rec- overed by weak acid leaching in the Cadmium Plant'followed by counter-current decantat- ion, ion exchange concentration, precipitat- ion of cadmium sponge and partial refining to caustic refined cadmium metal. Cadmium not eliminated during sintering is volatilised in the I.S.F. and subsequently recovered as zinc alloy by distillation in the zinc ref- ining columns of the Zinc Refluxer. The partially refined cadmium metal and cadmium- zinc alloy are blended as feed to the cadm- ium refining column where separation and recovery of cadmium is effected. Condensate from the column is further refined under caustic soda flux and cast into anode shapes. Production is 200 t.p.a. at 85% recovery of cadmium in concentrates. Emphasis is placed on changes from the practice described by Baker and Munro (1965) and upon operation

Jan 1, 1972

By Graham A. Mathieson

A detailed breakdown of capital and operating costs is an essential element in the planning and evaluation of any mining project. The OPCOST System was developed by Golder Associates to provide mining engineers with the facility to synthesize detailed cost estimates for all aspects of an operating or potential open pit mine. The system can also be applied to underground mines equally as well. Such estimates can be prepared at a variety of levels depending on the detail required by the project. The OPCOST System is a suite of computer programs linked through a common hierarchical data base. It simulates the thought and reasoning processes within the quantity takeoff and cost estimation phases of a mining project. The system was developed as a mining cost engineering tool on the basis that it would have to satisfy a variety of purposes, namely:

Jan 1, 1982