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By I. S. Blair

The introduction of the 36 MVA smelting furnace at Mufulira, and the experience gained during the first five years of operation have been described previously (6). Based on this experience the furnace was rebuilt in 1977., Details of the modifications made during this rebuild are described. Subsequent to the rebuild, refractory failures, particularly in the electrode ring bricks of the sprung arch roof, continued to cause concern, and repair and improved roof control methods are described. Electrode breakages continued, but developments in casing design and electrode preparation have resulted in significant improvements. Modifications in the electric furnace gas handling system are outlined, together with details of further changes to be implemented in the near future. The systems developed for metallurgical control of the furnace and the thermo-dynamics of the process are discussed. The electric furnace at Mufulira is now operating at above design production levels, and has decisively justified the choice of this technology in situations with inexpensive electric power. The potential for further increases in production capacity from the Mufulira unit, and improvements in design for new units are discussed.

Jan 1, 1983

By Alexander Sutulov

It is calculated that since the beginning of last century, which practically coincides with the beginning of the Industrial Revolution, our civilization has consumed around 239.5 million tons of copper (see: Table 1). According to the most pessimistic projections of today, with only a 2.5% annual growth rate in demand, we are bound until the end of this century to consume another 200 million tons of copper in remaining 17 years. A recent study made by US Bureau of Mines (1) indicates that the proven ore reserves of 150 major operating mines and about 120 deposits sufficiently explored for development and feasibility studies accumulate a total mass of 49.3 billion tons of ore, assaying an average of 0.82% Cu and containing around 324 million tons of recoverable copper. Consequently, there is a high grade of probability that the bulk of our future ore supplies, for our demand of, say, next 25 years will cane precisely from these mines. The interesting point in USBM study is that it indicates the recoverable byproduct content of these ores and which is: 118.2 million troy ounces of gold 2277.4 million troy ounces of silver 7.1 million tons of lead 24.7 million tons of zinc 1.3 million tons of nickel 3.1 million tons of molybdenum 765 thousand tons of cobalt, and 720 thousand troy ounces of platinum. This information gives us a relatively reliable profile of our future ores for next 25 years, and thus makes possible evaluation of byproduct credits in our future copper mining and producing activities.

Jan 1, 1983

By Dennis R. Twining

Recently a mining analyst for a major bank called me to say that during his travels he had encountered an electric utility interested in a new uranium supply. Since we produce uranium as a by-product of phosphate operations rather than as a primary product, he assumed we simply sold our output in the spot market and that a new prospective purchaser would be of interest to us. This assumption was incorrect; the uranium had already been sold on a long term basis at terms more favorable than the currently depressed spot market. From the outset our approach to the marketing of uranium was based on the principle that by-product marketing is not unlike primary product marketing. This was particularly appropriate in the case of uranium, as we were planning a considerable technical and capital commitment to a new business. This illustrates: that the fundamental principle in by-product marketing is to follow a primary product strategy; that the terms "by-product" or "co-product" are creations of accountants; that they have no place in marketing decisions! Traditionally, the term "by-product" has implied that only a secondary marketing effort is required. Recent history has contradicted that view by demonstrating that by-product values can have marked impact on a mine's revenues and costs. In fact, by-product values can spell the difference between success and failure.

Jan 1, 1983

By P. Rooney

In due course, new smelters will have to be installed in order to meet the increasing worldwide demand for copper. This paper presents the results of a study made for the purpose of identifying the most desirable countries in the world in which to locate a new smelter. Both sociopolitical and economic factors were taken into account. Criteria developed and methods used to assess each possible location are described. The study indicated that the most interesting potential locations are Canada, -Chile, Portugal and the USA for new copper smelting complexes.

Jan 1, 1983

By P. J. Mackey

New and emerging, as well as proven technologies for the smelting of copper, nickel, lead and zinc are briefly reviewed. The number of new technologies available today is greater than at any time in the past, and interest and development activities remain high despite the economic dif-ficulties faced by the non-ferrous metallurgical industry. Part of the impetus is provided by the realization that only the most cost effective producers will remain competitive, and that new technology is one key to cost effectiveness. The commercially proven "new" copper smelting processes can now be considered to be conventional- technology, and are expected to dominate copper smelting for acme time. There is a growing. interest in continuous copper converting, although direct smelting and converting to copper in one vessel remains the- ideal. There is little activity in nickel smelting. After many years. of development, it appears that several new direct lead smelting processes will soon be a commercial reality. The electrolytic zinc process is expected to continue its dominance, although there is a renewed interest in pyrometallurgical approaches. One of the new zinc processes, and a molybdenum smelting process, illustrate the possibilities of using plasma technology in non-ferrous metallurgy. In the area of complex sulphides, there is perhaps less interest in the treatment of bulk con¬centrate, and more in the treatment of so-called dirty copper concentrates. Much of the technology ancillary to smelting has remained relatively unchanged, and more effort must be made to advance the technology in areas such as materials handling, gas cleaning and sulphur fixation, and energy recovery. More attention to engineering design is also needed. Escalating capital costs may make mini-smelters attractive, but imaginative technology and innovative engineering will be required to make them cost effective. Finally, a glimpse is offered of the smelter of the future.

Jan 1, 1983

Past issues of Minerals and Materials have discussed such aspects of the economy as consumption and investment expenditures, interest rates, productivity, and international trade barriers and their effect on the minerals industry here and abroad. In this issue, we will (l) look at recent indications of a possible economic recovery, (2) present 1983 expectations reflecting the results of industry surveys conducted by the U.S. Department of Commerce (DOC), and (3) briefly discuss the contribution of the U.S. mining industry to total gross national product (GNP). THE RECOVERY Throughout most of 1982, DOC's Composite Index of Leading Indicators provided evidence of impending improvement in the economy. The index increased moderately during eight of the months in 1982 and then jumped an estimated 3.6 percent in January 1983 (table 1). While the leading indicators continued to predict improvement, the general economy, as measured by the Index of Industrial Production, continued its slide through November 1982 (table 2). Finally total industrial production increased in December 1982 and continued on an upward path in January and February, as predicted by the leading indicators.

Jan 1, 1983

By Christopher J. Farrow

This paper describes the grinding circuits installed at two remote sites in northern Canada. One is Cominco's Polaris Project at Little Cornwallis Island; a barge-mounted lead/zinc concentrator. The other is Echo Bay Mines' Lupin Project at Contwoyto Lake, 400 km northeast of Yellowknife, a gold mine, all components of which had to be flown to the site. Logistics and considerations of operating and maintenance presented challenges which were met by innovative design. The evolution of the grinding circuits is discussed. Both plants are operating at design throughput.

Jan 1, 1983

By V. P. Keran

The lead and copper smelting processes employed by Mount Isa Mines Limited, Mount Isa, Australia, are used to illustrate an operating viewpoint of some problems and solutions encountered in existing commercial sulphide smelters. The smelting processes discussed; include updraught sintering, blast furnace and reverberatory smelting, and converting. Selected examples are given of methods implemented, and options available, to improve the productivity and efficiency of conventional smelting processes.

Jan 1, 1983

By B. W. Dunning

The Bureau of Mines investigated the concentration and distribution of precious metals in the various fractions produced from mechanical processing of obsolete military electronic scrap. Whole avionic units, printed circuit cards, and electrical connectors were processed and analyzed. Materials recovered included baghouse lights, wire bundles, mag-netics, and metal concentrates from eddy-current and high-tension sepa-ration. Higher value fractions were processed by a commercial toll refiner for recovery of gold and silver. Lower value fractions were analyzed by the Bureau. Three fractions, the lights, wire bundles, and metallics from high-tension separation, contained most of the precious metals. Depending on the type of scrap feed, these fractions represented 34 to 60 pct of the original sample weight. Collectively, they represented 68 to 97 pct and 75 to 98 pct of the contained gold and silver, respectively.

Jan 1, 1983

By Peter Fischer

A demonstration plant for QSL technology with a continuous through-put of up to 10 t/h concentrate has been in operation at the Berzelius smelter, Duisburg, Germany since early 1981. In the QSL-process, both oxidation and reduction steps are performed in a single horizontal long cylindrical reactor. In the present demo-reacior, 2.5 M diameter by 22 M long, these steps are separated by a low partition wall with an underflow opening, to prevent backmixing of slag. -Tests on a variety of concentrates, including high-lead Missouri-type material and lower grades, have shown recoveries and consumables indicating very attractive economics. Investment cost estimates further enhance the economic attractiveness. Environmental protection afforded by the QSL system is a major advantage. The process has proven its reliability and versatility and is now ready for commercialization. Continued test work, including smelting secondary lead materials, is planned.

Jan 1, 1983

By J. C. Yannopoulos

The quest for a continuous copper smelting and converting process, which has been going on for a long time, has not as yet reached its objective. The most recent efforts for the development of a continuous copper?making process started about two decades ago. Among the contending proposed processes, four have been piloted and three of them are currently in operation: the WORCRA process., the NORANDA process, the MITSUBISHI process, the OUTOKUMPU process. The WORCRA process, after some long pilot plant tests, failed to develop as an industrial process: The NORANDA process, as currently operating, is a smelting process and not a continuous copper?making reactor as initially conceived. The MITSUBISHI, although the only continuous process, has not been widely accepted. The OUTOKUMPU process can be applied only to a low iron concentrate feed and co?produces blister and high in copper slag. The thermodynamics of these "continuous" systems and the practical problems of their industrial application are reviewed and discussed. The achievement of efficient and inexpensive environmental control should' be the primary objective of any new process development. A review of the environmental problems of the copper industry indicates that the quest for a continuous smelting and converting furnace should be intensified.

Jan 1, 1983

By O. Llewellyn Jack

From September 1978 to December 1983, ESD Corporation (formerly a Division of FMC Corporation) undertook the development and testing of a bidirectional auger under contract with the U.S. Department of Energy. Underground testing began in August 1981 at Peabody Coal Company's Marissa Mine near Marissa, Illinois. The auger was developed to increase mine production and coal recovery without increasing land subsidence. It bored 4-foot-diameter by 10-foot-deep holes into pillars on 7-foot centers (each hole recovering 5 tons). All operating during this test was performed by maintenance personnel with the goal of finding ways to increase the machine potential. The maximum excavation rate achieved was 1.4 tons per minute. It was concluded that the concept of drilling short holes to extract coal from underground pillars without surface subsidence was practicable with a wheel mounted auger, but that more power was desirable for this mine, and that the hydraulically driven augering system that provided experimental versatility was not sufficiently reliable for production use.

Jan 1, 1983

The Minerals Data Source Directory is a compilation of descriptive information on the availability, content, and location of minerals data in the Federal Government. It is intended to assist Government personnel and the general public in locating and acquiring minerals information. Included in the Directory are descriptions of data bases, publications, information systems, and information offices containing data pertaining to ail aspects of mineral production, consumption, trade, and related information. These mineral data sources include the Federal agencies such as the Department of the Interior's Bureau of Mines and Geological Survey whose major mission is the collection and dissemination of mineral information. Also included are agencies such as the Departments of Agriculture, Commerce, Labor, State, Transportation, and Treasury, the Central Intelligence Agency, the Environ- mental Protection Agency, the Federal Reserve System, the interstate Commerce Commission, and the Securities and Exchange Commission, whose primary mission is the collection of data in nonmineral subject areas, but in which the mineral industry is a component.

Jan 1, 1983

By Keith D. Rosbury

The basic objective of this project was to determine the cost-effectiveness of dust control used on unpaved mine haul roads. Field testing was conducted at three surface coal mines (two in Wyoming, one in southern Illinois) for a total of 20 weeks. The highest control efficiency measured for a chemical dust suppressant, 82 percent, was for calcium chloride two weeks after application. Generally, however, the control efficiencies hovered in the 40 to 60 percent range over the first two weeks since application, and then decreased with time. After the fifth week, the limited number of data points suggest a control efficiency of less than 20 percent. Composite watering data were fairly uniform. Watering once per hour resulted in a TSP control efficiency of approximately 40 percent. Doubling that application rate increased the control effectiveness by about 15 percent to 55 percent. Chemical dust suppressants (primarily salts and lignons) can be shown to be more cost-effective than watering under some conditions. Data summaries and the analysis of data are contained in Volume I. Volume II contains basic data.

Jan 1, 1983

By Jaan Kiusalaas

This report is a self-contained User Manual for a computer program called SPASID -- Subsidence Prediction and System Identification. The program has two primary functions: (i) Precalculation of ground movements due to underground mining operations using the influence function method; (ii) Computation of influence function and site parameters from measured displacements. SPASID is written in FORTRAN and consists of four modules: (i) Preprocessor Module that prepares and maintains surface and mine data bases; (ii) Subsidence Computation Module that predicts movements of the surface; (iii) System Identification Module which is used to calculate the optimal influence function parameters, and (iv) Postprocessor Module for generating graphic displays of subsidence data. The last module is somewhat machine dependent but has internal documentation to indicate potential changes. All of the modules may be run in either batch or interactive mode. The manual does not assume previous knowledge of the influence function method or programming competence.

Jan 1, 1983

By Jacqueline V. Rich

The relationship between surface and ground water quality and copper mining in the Globe-Miami area is investigated in this three-year study. Methods to prevent, minimize, mitigate, or treat polluted waters are identified and evaluated. Best Management Practices are incorporated in a recommended plan to manage the area's water quality.

Jan 1, 1983

The evident need to improve the reliability of fluid power systems in underground coal mining equipment prompted the U.S. Bureau of Mines, and later the Department of Energy, to contract with the Fluid Power Research Center at Oklahoma State University for a research project to develop methods for achieving this end. Since the work of the contract was completed at about the time DOE was relinquishing its underground coal mining projects to BOM it was decided to issue the final report under 80M cover. The contract revealed that the major causes of poor reliability were: (1) poor overall system design, (2) poor component contamination toleranace, (3) poor system filtration, and 4) poor maintenance practices stemming from a lack of defined maintenance procedures and enforcement of same. This report demonstrates the variability of the reliabilities of components of similar performance description when subjected to standard tests. Improved design procedures are recommended and the information needed to specify and select components whose reliability is predictable and optimum without sacrifice in performance or significant increase in envelope size.

Jan 1, 1983

By Thomas F. Clemens

This paper covers various changes in government regulations, taxation, and legislation for the past two plus years and the up- coming one. Part of the paper will discuss recent business conditions and how they have affected the cement and lime industry.

Jan 1, 1983

By F. Ajersch, M. Rigaud, M. Jallouli

"Le gonflement des boulettes d'hématite à été étudié à l'aide d'une méthode de mesure standard ISO ainsi qu'à l'aide d 'une méthode de mesure dilatométrique.La première méthode a servi à l'étude des boulettes haute silice (5% SiO2) dont l'indice de basicité (IB = CaO + MgO -i- SiO2 + Al2O3) a été ajustée soit à l'aide d'une addition de dolomie, soit à l'aide d'une addition de pierre à chaux, soit à l'aide d'une addition de ces deux composes. L'indice de basicité variait de 0.05 à 0.12. Les résultats de gonfle ment obtenus à 1000?C dans une atmosphère de 40 CO - 60 N2 ont permis de montrer qu’indépendamment de l'indice de basicité c'est la dolomie qui contribue le plus à diminuer le gonflement par rapport à la pierre à chaux. L'utilisation de l'indice de basicité comme critère de sélection des boulettes est discutée.La méthode dilatométrique a servi à l'étude du gonfle ment de deux types de boulettes préparées à partir de deux concentrés de fer et dont la teneur en silice a été fixée à 2.5% et 0 5%. Ces deux types de boulettes ont reçues les mêmes additions de liant en quantité et en nature. La détermination en continue du gonflement, à 950?C dans 40 CO - 60 N2, a permis d'une part de mieux cerner le niveau de réduction auquel correspond le maximum de gonflement et d'autre part de montrer que l’allure des courbes de gonflement est étroitement liée à la nature du liant. Une augmentation de la teneur en silice des concentres contribue à diminuer le gonflement des boulettes.Des essais de réduction de gonflement non isothermes ont été réalisés à des montées de température à 10 et 20?C/min. Les résultats indiquent que le gonflement déterminé dans les conditions non iso thermes est inferieur à celui obtenu lors des essais isothermes. On discute alors de la validité des essais standards de gonflement qui sont utilisés pour prédire le comportement des boulettes lors de leur réduction dans un haut fourneau."

Jan 1, 1983

By Alastair M. Lumsden

A study was initiated to examine the ways in which a number of foreign countries classify and regulate metal/non-metal mines which experience problems due to naturally-occurring flammable gases. Twenty countries were selected for study, and useful information was obtained from sixteen of these. Nine countries were visited (five of them twice) to hold meetings with representatives of government mine regulatory agencies and mine operators, and to visit mines encountering methane and other gases (carbon dioxide, nitrogen). In the later stages of the study seven gassy metal/non-metal mines in the United States were visited so as to provide a basis for comparison, and hence the evaluation of both the U.S. and foreign gassy mine regulations. In addition to obtaining copies of the mining laws and regulations of a number of foreign countries, nine foreign gassy mines, and the seven in the United States were documented in as much detail as possible. All this information is presented, along with appropriate conclusions and appendices. The study took two years and three months to complete.

Jan 1, 1983