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By R. D. Pehlke, J. V. Gluck

AS a portion of a general study of liquid-metal thermodynamics, high-temperature galvanic cells were used to study the effect of added dilute solutes on the activity of zinc in dilute solution with molten bismuth in the range 450° to 650°C. 1,2 The cells were of the type The experimental procedures have been described previously.1 In the course of studies conducted in the bismuth-rich corner of the systems Bi-Zn-Au and Bi-Zn-Cu, marked discontinuities were observed in the electromotive force-temperature relations for a number of the experimental compositions. Above the discontinuity temperatures, the relations, which were linear, exhibited slopes similar to the binary alloy of the same mole fraction zinc, as shown in Figs. I and 2. Below the discontinuity temperatures, the slopes were markedly different, but the relations remained linear. In general, as the amount of the third eletnent was increased, the slope of the lower portion of the relations tended to become less positive. The slopes of electromotive force-temperature relations reflect the entropy of mixing of zinc and, therefore, the occurrence of a discontinuity marks the transition between two different equilibrium situations involving the solution of zinc. A number of other investigators3-5 have used such observations to determine liquidus boundaries in binary alloys. Since the upper portions of the ternary electromotive force-temperature relations of this study had the same slopes as the binary alloys, the discontinuities are interpreted as marking the transition between the single-phase liquid region and the underlying two- and three-phase regions. Reference to the Zn-Bi equilibrium diagram6 confirms that the binary alloys were single-phase liquids at the experimental temperatures. Fig. I shows the electromotive force-temperature relations for the alloys containing Bi-Zn-Au and Fig. 2 shows similar relations for the Bi-Zn-Cu alloys. In the lower portion of each figure, the temperature of the discontinuity is plotted vs the mole fraction of the added solute at the various levels of zinc concentra- tion. Cross-plots from these curves at constant temperature permitted the construction of the partial liquidus surface isotherms shown in Figs. 3 and 4.

Jan 1, 1967

By T. van Heerden

A range of supported gold catalysts was prepared by ion exchange, varying many of the preparation variables, including concentration in the precursor solution, washing procedure, as well as drying and calcination procedures. These catalysts have been characterized extensively. TEM images show essentially the same crystallite size distributions, between 2?5 nm, for almost all catalysts, the only exception being catalysts not washed in ammonia, which did not show any small crystallites. Additional characterization with SEM yielded an interesting discovery. Catalysts that appear identical on the TEM also contain some large crystallites in the range of 50?500 nm. Differences in dispersion due to the drying procedure not seen on the TEM can now be observed. Oxygen chemisorption is being investigated as an additional method to characterize gold based catalysts to complement the typically used electron microscope techniques.

Jan 1, 2012

By Luis Espinoza

La unidad minera Tintaya al igual que la Unidad Minera Antapaccay, son las operaciones de la división Perú de Xstrata Copper dedicados a la producción y comercialización de concentrado y cátodos de cobre. Sin embargo, la mina está en su última etapa de vida. En este sentido, surge el proyecto de integración de la unidad Antapaccay, donde se busca prolongar la vida útil de la mina y por consiguiente, el de la actividad económica minera en la provincia de Espinar. Por ello, el presente trabajo, describe los efectos de esta expansión de la explotación minera a través de la Unidad Minera Antapaccay que utiliza las instalaciones de Tintaya, manteniendo los planes de inversión social y el desarrollo económico local y regional.

Sep 21, 2013

By A. K. Majumder

The multi-gravity separator (MGS) is a novel piece of equipment for the separation of fine and ultra-fine minerals. However, the published literature does not demonstrate its use in the separation of coal fines. Therefore, an attempt was made to study the effects of different process variables on the performance of an MGS for the beneficiation of coal fines. The results obtained from this study revealed that among the parameters studied, drum rotation and feed solids concentration play dominating roles in controlling the yield and ash content of the clean coal. Mathematical modeling equations that correlate the variables studied and the yield and ash contents of the clean coal were developed to predict the performance of an MGS under different operating and design conditions. The entire exercise revealed that the MGS could produce a clean coal with an ash content of 14.67% and a yield of 71.23% from a feed coal having an ash content of 24.61%.

Jan 1, 2007

The mechanization of the coal industry in New South Wales involved the introduction of large face and transport machines. The trend is towards still higher capacity units with .greater horsepower and it became apparent that a potential risk of damage to the hearing of workmen existed. In order to assess whether the sound levels were SUfficiently high to impair the hearing of workmen a sound level survey of all major operations in the industry was carried out by the Mining Engineering Division of the Joint Coal Board.The results indicated ·that the operations could be classified into three categories of risk, probably hazardous, of doubtful hazard due to the intermittency of the operations, and of low hazard.Legislation has subsequently been enacted requiring the wearing of hearing preservation aids in some of the probable risk operations.

Jan 1, 1974

By Fookes R. A, Bunch K, Gravitis V. L, Watt J. S

The combustible volatile matter in coal mine roadway dusts (CVM) has been determined using x-ray backscatter techniques. The correlation between x-ray and chemical techniques is reasonably good for the 92 samples from collieries on the Bulli seam, and the maximum error expected at the maximum level of 11· 5 weight per cent CVM permitted in the N.S.W. Coal Mines Regulation Act, 1912, as amended, is about ± 2·5 weight per cent. This x-ray technique can be used only when the combustible volatile content of the coal matter (cvm) varies within a limited range, and a separate calibration is required for each coal seam.Portable equipment based on a radioisotope x-ray source ahd digital ratemeter makes possible simple and rapid analysis, and with adaptation to use in coal mines should lead to much more comprehensive testing- ofroadways and hence improved overall prevention of coal dust explosions.

Jan 1, 1977

By C. Crussard, R. Tamhankar

It is the policy of The Metallurgical Society to provide, in the TRANSACTIONS OF THE METALLURGICAL SOCIETY OF AIME, a prompt and accurate medium for publication of reports of significant new research in both the scientific and engineering aspects of metallurgy. Papers submitted to the Society are judged by competent reviewers accord-ing to established criteria for technical merit, accuracy, originality, and presentation. STAFF: Editor, Gerhurd Derge Carnegie Institute of Technology Schenley Park Pittsburgh 13, Pa. Editorial Assistant, M. A. Redmerski Staff Coordinator, James J. Burke THE METALLURGICAL SOCIETY: W. R. Hibbard, Jr., President; J. C. Kinnear, Jr., Past-President; John Chiprnan, Vice President; T. D. Jones, Treasurer; R. W. Shearman, Secretary. PUBLICATIONS COMMITTEE OF THE METALLURGICAL SOCIETY: A. W. Thornton, Chairman; Dennis Carney, John Chip-man, J. C. Fulton, J. H. Hollomon, H. H. Kellogg, A. E. Lee, R. Maddin, J. D. Sullivan, and D. Swan. Review and selection of manuscripts is under the supervision of the following Publications Committees: Extractive Metallurgy Division: T. B. King, Chairman; S. J. Dickenson, R. P. Hermsdorf, R. Schuhmann, Jr., and P. T. Stroup. Institute of Metals Division: Robert Maddin, Chairman, F. Lincoln Vogel, Jr., Vice-chairman, W. A. Backofen, R. W. Balluffi, J. H. Bechtold, M. B. Bever, R. S. Busk, C. G. Goetzel, Paul Gordon, C. D. Graham, .Jr., Robert F. Hehemonn, R. I. Jaffee, F. E. Jaumot, Jr., Irving R. Kramer, A. J. Lena, Harold Margolin, C. J. McHorgue, Russell A. Meussner, J. B. Newkirk, H. W. Paxton, G. E. Pellissier, I. S. Servi, Alan U. Seybolt, A. J. Shaler, and Jack Washburn. Iron and Steel Division: J. C. Fulton, Chairman; T. B. King, F. C. Langenberg, W. 0. Philbrook, and T. 0. Winkler. Published bimonthly by the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc., 29 West 39th Street, New York 18, N. Y. Telephone: PEnnsylvania 6-9220. Subscription $20 per year for non-AIME members in United States and North, South, and Central America; $25, foreign; $5 for AIME members. Single copies, $4.00, single copies foreign, $5.00. The AIME is not responsible for any statement made or opinion expressed in its publications . . . Copyright 1958 by the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. . . . Registered cable address, AIME New York ... Indexed in Engineering Index, Industrial Arts Index, and Chemical Abstracts... Second class postage paid at New Yark, N. Y., and Ann Arbor, Mich. Volume 212, Number 6.

Jan 1, 1959

By Bryan M. Maybee

The scheduling of underground mining activities is a complex task, in particular because of the requirement to satisfy a large number of constraints. A Schedule Optimization Tool (SOT) for underground mine planning is described, and its use for investigating strategic decisions is illustrated by means of a case study. The main components of SOT include: a genetic algorithm, which searches for optimal schedules; guidance, the application of heuristic rules to guide the genetic algorithm; and sliding, which implements just-in-time development. For the case study, SOT is employed to generate schedules at various ore capacities, accounting for the appropriate financials in each schedule evaluation. The case study finds that preliminary scheduling performed before invoking SOT, intended to provide a good starting point for the search, does not ultimately lead to higher value schedules. Two key uses for SOT are identified. A mine planner can save time by using SOT to produce high-value scheduling alternatives. This process ensures a broader investigation of the value that the deposit can yield. Also, SOT can be used to validate strategic and tactical decisions, by scheduling under alternative scenarios. Both uses produce high value schedules conforming to all imposed resource constraints.

May 1, 2009

By E. F. Johnson, V. O. Naumann, D. P. Bossler

A method is presented for calculating individual gas and oil or water and oil relative permeabilities from data obtained during a gas drive or a waterflood experiment performed on a linear porous body. The method has been tested and found both rapid and reliable for normal-sized core samples. INTRODUCTION Individual oil and gas or oil and water relative permeabilities are required for a number of reservoir engineering applications. Chief among these is the evaluation of oil displacement under conditions where gravitational effects are significant, such as a water drive or crestal gas injection in a steeply dipping oil reservoir. Numerous proposed methods of obtaining relative permeability data on reservoir core samples have been too tedious and time consuming for practical use, or have yielded questionable and sometimes inconsistent results. A method has been developed by which the individual relative permeability curves can be calculated from data collected during a displacement test. The method is based on sound theoretical considerations. Using this method, with a properly designed experimental procedure, relative permeability curves can be obtained using core samples of normal size (i.e., 2 to 3 in. in length and 1 to 2 in. in diameter) within a few days after receipt of the core. In a recent publication D. A. Efros1 describes an approach to the calculation of individual relative permeabilities that is based on the same theoretical considerations. We believe the approach described in the present paper is more adaptable to practical application than the method implied by Efros. In addition, comparisons with independently determined relative permeabilities are furnished to substantiate the reliability of the new method. DERIVATION Previously the theory of Buckley and Leverett as extended by Welge2 as been used to calculate the ratio of relative permeabilities. In the derivation which follows, this theory is further extended to permit calculation of the individual relative permeabilities. The theory assumes two conditions which must be achieved before the method is applicable. They are that the flow velocity be high enough to achieve what has been termed stabilized displacement,3 and that the flow velocity is constant at all cross sections of the linear porous body. In stabilized displacement the flowing pressure gradient is high compared with the capillary pressure difference between the flowing phases. The high pressure drop insures that the portion of the core in which capillary effects predominate will be compressed to a negligibly small fraction of the total pore space. The assumption of constant flow velocity at all

By Patricio Santis, Jacopo Seccatore

Artisanal and Small-scale Mining (ASM) is a prominent activity in the extractive industry: considering only gold, it produces about 20% of world market supply. Despite this fact, ASM is generally associated with negative aspects of its environmental impact, and operational research is generally neglected. This paper emphasizes the peculiarity of the drilling and blasting systems of small underground mines in selected South American Countries. Such Countries, while having large mineral deposits and well recognized large-scale mining activities, at the same time still present on their territory ASM activities that are archaic, highly inefficient and dangerous for the safety of its operators. This paper documents drilling and blasting activities from gold mining in Ecuador and Chile. First, are described the outdated and often non-rational techniques employed by miners, to provide a general framework of the current methods. Then, it is shown what can be improved and how the current methods can be modified. Finally, are shown some field applications and the comparisons of the results obtained. One case shows how blast pull efficiency can be increased of from 82% to 98% by changing non-rational applications of explosive products. Another case shows how, by rationalizing blast designs, drilling and blasting costs can be reduced by 9% per month, the advance by blasting increased by 29% and the blasting efficiency increased from 70% to 90%. Finally, it is concluded that examples of application show how operational improvements are easily applicable on the field, relying only on tools and resources of artisanal mining, but combining solid engineering bases with confidence-gain and respect for the experience of the miners.

The iron ore deposits of the Port Hedland district of North Western Australia are associated with band'ed sedimentary iron formations that form part of the local succession of folded and faulted Archaean volcanic and sedimentary rocks. The iron formations are regarded as the protore beds or sources of the iron which became concentrated by supergene processes to form commercial grade iron ore deposits.Iron oxide deposits occurring in situ within the protore beds are considered to be of residual-replacement origin, due to supergene leaching of gangue minerals and' deposition of secondary iron oxides in their place, Two types of deposit have been recognized. Lode deposits are deep lenses of massive hematite located adjacent to major faults. These deposits are thought to be very old and to have originated by supergene processes during the long period of erosion represented by the major unconformity between the Archaean rocks and the overlying Proterozoic beds. The other type, known as crust ore deposits, are shallow cappings of hematite and goethite on hills formed by the outcrops of steeply dipping protore beds. These deposits could have originated as far back as the early Mesozoic and it is possible that the ore-forming process is continuing at a slow rate at the present day.Deposits formed by erosion and re-deposition of material derived from pre-existing residual-type deposits are known as derived deposits. These include conglomerates and scree accumulations of various types and ages and pisolitic deposits formed by supergene leaching of transported detritus. Derived deposits range in age from early Proterozoic to Recent. The presence of pebble accumulatio,ns of lode-type hematite in the Proterozoic basal conglomerate provides good evidence that lode hematite deposits existed in pre-Proterozoic times.INTRODUCTIONThe existence of iron ore deposits in the Port Hedland district of Western Australia has been known since the beginning of the century, but little attention was paid to them untIl the 1930's, when the Commonwealth Aerial, Geological and Geophysical Survey of Northern Australia carried out investigations of most of the then known mining fields of the Northwest Division. The only iron...

Jan 1, 1964

Copper ores are widespread through the Lachlan Geosyncline in New South Wales, but the size of the orebodies is generally small. The largest deposits occur in the Cobar district where an iron-rich copper ore type has been developed in Silurian sediments. Similar de- . posits to the south in the Nymagee-Mt. Hope-Melrose districts are related to quartz feldspar porphyries of probable Upper Silurian age. Deposits to the east in the Tottenham-Girilambone districts are less complex mineralogically and are possibly related to an ultra-basic source.Copper mineralization in the Highlands further to the east is often developed in Ordovician andesite or MiddleUpper Silurian acid volcanic sequences. The deposits in andesite contain considerably less galena than those in the acid extrusives; a small proportion of the mineralization in the latter has texture, mineralogy, and geologic setting analogous to the Captain's Flat copper-Iead-zinc deposit, for which both syngenetic and epigenetic origins have been proposed. Very little copper mineralization occurs within granitic material, even though rocks of this type ranging from Silurian to Carboniferous in age crop out through much of the geosyncline, and the extent of the metal contribution from plutons to the deposits in volcanics is open to question. Numerous deposits are known in the contact zone around Mid-Devonian and Mid-Carboniferous granites, however, and the formation of these orebodies has undoubtedly been influenced by plutonic activity. Small occurrences of copper with associated minor nickel sulphides are developed in a narrow serpentinite belt of possible Lower-Middle Devonian age in the southern section of the Highlands.

Jan 1, 1970

By Crazy Horse - The Journal of Explosives Engineering - Vol 20 No 1

The crew at Crazy Horse Memorial has produced a w o n d e rful new video called “The Fine Art of Mountain Carving.” The video closely examines for the first time, the extraordinary explosives engineering on the Crazy Horse mountain currently in pro g ress in the Black Hills of South Dakota. The 56-minute video takes the viewer up the mountain for a behind-the-scenes look at the drilling and blasting crew at work on the mountain. The video was written, edited and produced by Robb D e Wall and is available exclusively from the Crazy Horse Memorial in both DVD and VHS formats. For i n f o rmation, see www.crazyhorsememorial.org The following, is a brief summary of the 25 steps involved in carving the mountain. The video goes into extensive detail on each of the 25 steps. Both those in the explosives industry and those outside the industry will find the video intere s t i n g .

Jan 1, 2004

By A. Mazhary, T. Huff

Sensor-based ore sorting technology is a growing area of interest due to lower-grade ore deposits and higher costs of processing, among other reasons. Among the sensors currently utilized in the particle sorting industry, X-Ray Fluorescence (XRF), as the only sensor with elemental analysis capabilities, has always attracted more attention. Currently, the bench-scale amenability tests for this sensor are performed using hand-held XRF analysers. However, this testing method overestimates the performance of the XRF sorter, and therefore, the results from these tests can be misleading and are often mispresented. The work presented here was conducted on a copper mine and investigates how the sensor’s sensitivity to copper deteriorates under different testing methods. This work compares and correlates the results of an Olympus hand-held XRF analyser, static, and dynamic sorter responses with the actual grades of the rocks. The results confirmed that, the sorter response was extremely prone to blind spots. Furthermore, the results demonstrated that although the static sorter’s responses were comparable in terms of rock identification to those of the hand-held XRF analyzer and assays, the accuracy of the dynamic sorter response deteriorated both as a function of grade of the rocks as well as the potential for blind spots. INTRODUCTION Sensor-based sorting technology has been gaining increasing attention even by larger mining corporations as ore grades decrease, deposits get deeper and therefore cost of mining and processing increases. There are various types of sensors that are currently being used in the particle sorting industry such as X-Ray Transmission (XRT), Color, Electromagnetic (EM), Near-Infrared (NIR) and others. However, none of the sensors are capable of identifying and quantifying particles by the elemental content, except for X-Ray Fluorescence (XRF). XRF is a non-destructive, surficial analytical technique used to measure elemental composition of materials. X-ray fluorescence happens when a secondary x-ray (fluorescence) is released after a sample is bombarded by a primary x-ray source. From a sorting perspective, the most common and expected issues that are associated with XRF sorting are lower throughputs compared to other sensors due to particle presentation limitation as well as the need to wash the material before introducing to the sorter. However, one important issue that is mostly neglected is how the amenability tests are performed and how realistic the obtained results are. Current amenability test procedure utilises a handheld XRF analyser (such as an Olympus InnovX, as used in this work) on multiple, generally 4, sides of the rock and uses the average measured grade as a criterion for separation. While this is a widely accepted technique, it fails to consider some important factors such as exposure time and the distance between the sensor and the particle. These factors can significantly affect the sorting outcome.

Jan 1, 2019

By Sam Bang Jr, Rodney Burke

As mining progresses in the West, the depth of material has increased, making highwall stability a major factor in safety and production. The Jim Bridger Coal Mine’has made highwall stability a priority, concentrating on safety as well as increasing and improving production. Overburden depths are increasing dramatically; the geological environment consists of medium to sot? material, faulting, water, and current pit alignment not favorable to joint planes. Angle drilling the presplit at 20 degrees became necessaryas vertical presplit drilling produced wall failures.

Jan 1, 1998

By Pathies Nawej Muteb, Tom Strombotne, Karl Leetmaa, Irma Gabric, Keith Darby

"Continuous control of the final grinding product size is important to optimize gold liberation for Gold Milling operations. At Meadowbank Mine an on-line Particle Size Monitor has been employed successfully to achieve the targeted final grind which leads to optimizing the gold recovery at maximum grinding circuit throughput. The live monitoring of the final product particle size leads to a maximum grinding circuit throughput every minute during the process. This paper discusses the optimal utilization of the Particle Size Monitor to assist the Mill operator to maximize the grinding circuit throughput as the milling conditions change due to variable ore processed at Meadowbank Mine. Also the paper includes the usage of the Particle Size Monitor to guarantee the final grind target at each instant of the process.IntroductionAgnico-Eagle is a Canadian-based company that Trades on the TSX & NYSE (AEM). It owns eight mines (8) operating in Nunavut, Quebec, Finland and Mexico and has more than 7,500 employees (Figure 1). 1.6 M ounces of gold were produced in 2015 and the annual average annual production from 2016 to 2018 is forecast to be approximately 1.53 million ounces of gold.The Meadowbank Mine is located in Nunavut, Canada (Figure 2). The mine opened in 2010 and from 2010 to 2014 a total of 1.8M oz of gold was produced. The milling rate is 4.2 Mt per year with an average mill throughput of 11,900 tpd or 496 tph. Average annual gold production over life of mine is expected to be 450,000 ounces. Meadowbank has 775 employees, of which 265 are Inuit or 36% of the total workforce. Estimated life of mine is 2010 to 2018. Gold production in 2015 was 381,804 oz. Meadowbank was Agnico-Eagle’s largest Gold producer in 2015."

Jan 1, 2017

By R. V. Ramani, R. Stefanko, G. W. Luxbacher

C THRM 1 C CALCULATION OF MINE HEAD LOSSES FROM ALTIMETER SURVEY DATA TURN 2 C PENNSYLVANIA STATE UNIVERSITY - MINERAL ENGINEERING DEPARTMENT THRM 3 C THRM 4 C THRM 5 C THIS PROGRAM CALCULATES PRESSURE LOSSES USING THERMODYNAMIC RELATION- THRM 6 C SHIPS BASED ON POLYTROPIC FLOW BETWEEN STATIONS. FOR REFERENCE SEE THRM 7 C "A NEW TREATMENT OF MINE BAROMETER SURVEYS" BY M. J. MCPHERSON IN THRM 8 C 'THE MINING ENGINEER' NO. 109, VOL. 129, P 23. THRM 9 C THRM 10 C THRM 11 C THRM 12 C IDENTIFICATION OF ARRAYS THRM 13 C NOTE THE PROGRAM HAS BEEN DIMENTIONED FOR FOURTY (40) DATA POINTS THRM 14 C BASEC(6;2) BASE INSTRUMENT TEMPERATURE CORRECTIONS THRM 15 C TRAVC(6,2) TRAVERSE INSTRUMENT TEMPERATURE CORRECTIONS THRM 16 C BASER(I) BASE INSTRUMENT READING THRM 17 C TRAVR(I) TRAVERSE INSTRUMENT READING THRM 18 C TDRY(I) DRY BULB TEMPERATURE AT TRAVERSE STATION THRM 19 C TWET(I) WET BULB TEMPERATURE AT TRAVERSE STATION THRM 20 C ELEV(I) ELEVATION AT TRAVERSE STATION THRM 21 C VEL(I) AIR VELOCITY AT TRAVERSE STATION THRM 22 C TBDRY(I) DRY BULD TEMPERATURE AT BASE STATION THRM 23 C BASC(I) BASE READING CORRECTED FOR INSTRUMENT TEMPERATURE THRM 24 C TRAV(I) TRAVERSE READING CORRECTED FOR INSTRUMENT TEMPERATURE THRM 25 C BBASE(I) TEMPERATURE CORRECTED BASE READING IN BAROMETRIC THRM 26 C PRESSURE THRM 27 C BTRAV(I) TEMPERATURE CORRECTED TRAVERSE READING IN BAROMETRIC THRM 28 C PRESSURE THRM 29 C BTRAVS(I) BAROMETRIC TRAVERSE READING CORRECTED FOR ATMOSPHERIC THRM 30 C CHANGES THRM 31 C RELHUM(I) RELATIVE HUMIDITY THRM 32 C ASW(I) AIR SPECIFIC WEIGHT TURN 33 C R(I) GAS CONSTANT FOR MOIST AIR THRM 34 C STPRES(I) STATIC PRESSURE CHANCE BETWEEN STATIONS (I) AND (1-1) THRM 35 C TOPRES(I) TOTAL PRESSURE CHANCE BETWEEN STATIONS (I) AND (I-1) TURN 36

Jan 1, 1977

By F. Stober, D. Wanblad, J. Ndlovu, L. R. Nelson, L. P. S. de Villiers

The single six-in-line furnace of the Polokwane Smelter is the largest installed high-intensity furnace for platinum group metals (PGM) base metals sulphide smelting in the world. The furnace employs state-of-the art technology to deliver a planned throughput of 650 000 t/a dry concentrate at a design 68 MW power input. This furnace, at double the capacity of previously existing PGM furnaces, offers low unit operating and capital cost through the resulting economies of scale. Key features of the design include:

Jan 1, 2005

Some form of technical library is a necessity for every metallurgical plant, but its form and scope will vary with the conditions of each case. In its simplest form, it may consist of one or two mining journals and a few text books distributed amongst the staff. Again, it may be a separate establishment controlled by a clerk, the technical staff necessarily making its own research into the literature available. A still more elaborate organisation may be established both to supply information when requested and to keep the operating staff in touch with current matters of interest, and the library service of the Electrolytic Zinc Co. of Australasia is of this character.The necessity for such a service is due to several facts. The Company's interests are scattered over three States. Most of its staff members are remote from: good public library facilities and they have few opportunities for exchanging ideas verbally with other metallurgists and engineers. Then, too, the process of recovering zinc by electrolysis, is a young art of which the physical and chemical bases were far from fully known at the time the: Risdon plant was established. Most of the zinc produced is sold abroad, and this unsheltered industry can afford to miss no technical or economic development which may promote its efficiency. Add to these facts the geographical isolation of the Commonwealth and the case for an adequate library is complete.

Jan 1, 1934

A detailed study of the capital investment and production cost for copper electrowinning plants shows that significant savings in both can be achieved by increasing the current density. From the economic analysis it is determined that the optimum current density which will result in lowest capital investment and lowest operating cost is between 60 A/sq. ft. and 70 A/sq. ft., or at least three times as high as the Conventionally employed current density. The specific investment, expressed as $/ton-year, is found to be a function of both the current density and plant capacity and has a minimum value at the optimum current density. Empirical equations are developed for the purpose of estimating the capital investment and operating cost for plants of any production capacity operating at any current density.

Jan 1, 1972