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By W. P. Sykes

TUNGSTEN serves mankind in two major roles. The first of these is represented by the tungsten filament of the incandescent electric lamp, a common article of commerce. In the field of hard alloys it plays its second substantial part. A fortunate combination of physical properties in this metal ac- counts for its efficient service as a source of illumination. Tungsten melts at about 3400°C, has a relatively low vapor pressure and at the same time sufficient strength, both hot and cold, to serve satisfactorily as filaments, which may range in diameter from 0.060 to 0.0005 in. In the early days of the incandescent lamp, the pioneers realized the importance of using a substance of high melting point for the source of light. The metals osmium (mp approx. 2700°C) and tantalum (mp approx. 2850°C) were both employed to some extent. Tantalum actually attained some commercial importance in this field because it could be drawn into small wires of appreciable length. DUCTILE TUNGSTEN WIRE Before the year 1908, tungsten was considered a nonductile metal, since no one had succeeded in overcoming the brittleness so typical of the unworked metal at room temperature. The methods employed today in producing ductile tungsten wire were developed over a period of years. The process was largely determined by the exceedingly high temperature required to melt this metal. Even today the difficulties involved in producing an appreciable quantity of pure

Jan 1, 1953

By W. L. Price

Since they were first introduced in the United States in 1964, rail mounted bucket wheel stacker-reclaimers have gained wide acceptance by the coal burning power plant group. Other installations include those in phosphate and steel mill ore storage areas. First Installation in the U.S.A. Three basic types of bucketwheels for handling stored bulk materials are now being used in the U.S. Bucketwheel stacker-reclaimers came into use in the U.S.A. in 1964 at the Chalk Point power station built by the Potomac Electric Power Co. It was decided, after serious study, to install the first slewing-boom, rail mounted bucketwheel stacker-reclaimer at this installation. It was designed with a separately counter- weighted wheel boom because the fixed counterweight of the European designed bucketwheel made it possible for the machine to overturn backwards if the wheel rested on the ground due to a possible failure of the luffing system.

Jan 1, 1970

By E. H. Hamilton

WHEN starting a series of experiments on the use of powdered coal in lead blast furnaces to replace coke, I realized that in copper smelting the problem is simpler because the sulfur recovers the copper in the form of matte. In lead smelting there are greater difficulties because a reducing atmosphere must be maintained in the active, zone corresponding to each tuyere in order to get the best recovery of lead. Therefore, the feed of powdered coal must be quite regular, uniform and under control. The molten products issuing from the taphole are the resultant of the work of all the tuyeres and it can readily be con-ceived that one part of the furnace may be forming slag with a higher lead content than the slag formed in other parts of the furnace. At first, we used only one tuyere situated on the back of the furnace. This was for the purpose of getting all of our regulations under the regular operating conditions. We tried every known system of feed and found they were not dependable and our present system was finally worked out, and so far as we know, is the only working system that will give uniformly good saving in lead blast furnaces. We placed a Bristol self-recording thermometer on the feed floor. This gives a 24-hr. continuous record of the temperature of the gases leaving the furnace. We put a self-recording gage on the "15-lb." air used in the injector. A second recording Bristol gage was put on the low-pressure air (40 oz.). I realized that it was necessary that we should know the exact weight of coal going into each tuyere and that it should 'be under observation at all times. L. W. Kirk was assigned to the problem and developed the open sight feed and the distributor, so that we now have the coal being fed into each tuyere in sight of the men in charge. We have an apothecary's balance beside the furnace, and the operator takes the pan and inserts it under the stream of falling powdered coal for one minute, and places the pan on the scale, the other scale pan having weights indicating the desired amount to be fed to each tuyere per minute.

Jan 10, 1922

By Richard L. Rains

The U.S. Bureau of Mines conducted a field study of mines and prospects of the Black Canyon RARE II area (No. 5061), Inyo County, California, from June to October 1981. Geological) geochemical, and geophysical studies were conducted by the U.S. Geological Survey. The Black Canyon RARE II area is east of Owens Valley and 6 mi east of Bishop, California. The principal mineral commodities are gold, silver, lead, zinc, and tungsten. Properties with resources in and adjacent to the area are listed in table 1; the locations are shown on figure 1.

Jan 1, 1983

By Alex Henderson

The underground hard rock mining industry has had little change since the mobile equipment era began in the 1970s. Equipment has become larger and faster but has not kept pace with the following challenges: ? Improvements in safe production, ? Increasing demand for metals, ? Environmental improvements, ? Decreasing grades, ? Increasing depth of mining, ? More metal from underground vs. surface mining, and ? Energy and green house gas awareness. We are on the cusp of a new mining era and must rethink how underground hard rock mining must change in order to meet these challenges. This paper will show historical changes and propose a set of guiding principles for the next era of mining. Mining has changed over the last century. Initially mining was primarily an endeavor carried on by private companies with minor environmental controls and few social expectations other than employment. In the mid to later part of the century the mining industry was facing new challenges: deeper mines, the London Metals Exchange markets for pricing, and environmental concerns related to acidic rock drainage coming to the forefront. In today?s context, mining has evolved in complexity with the social and environmental aspects equally or surpassing the technical complexities such as expanding from mining hard rock to laterites, and mining lower grades or at greater depths. Nowadays, communities must be considered as partners, both locally and globally and the increased international visibility pushes the mining sector to take a more balanced approach to the business of mining (Fig. 1).

May 1, 2011

By J. Daraisme

Société le Nickel (SLN) exploits the Dôme lateritic nickel orebody at its Tiébaghi operations in New Caledonia. The site geology has an obvious bearing on recovery and metallurgical performance, and the controls are extremely complex at all scales: lithology, oxidation-reduction conditions, mineralogy, and multivariate geochemistry. In that context, establishing an adapted recoverable resource estimation method that is efficient and transparent proves an interesting challenge. The method must address the key notions of: ? Support effect: the exploration data-set can only warrant the estimation of large panels 20×20×3 m3, which are much larger than the selective mining units (SMUs) of 5×5×3 m3 ? Information effect: the selection at production stage uses estimates based on information much denser than that available for mine planning. The problem is rendered more complex in this type of deposit by the fact that the additive variables used for any estimation process (metal accumulation and ore tonnage) are not the ones used to establish the selection at mining stage (i.e. the nickel grade of SMUs, which is the ratio of accumulation on tonnage). Eventually, the selection criteria involve not only Ni grades but also other constituents such as Al2O3, Fe2O3, MgO, and SiO2. The solution presented in this paper is the construction of a platform of SMU multivariate simulations in the saprolitic horizon, together with efficient post-processing aimed at producing the multivariate recoverable resource estimates. The efficiency constraints imposed by the number of blocks to be simulated (1.5 million) lead to resorting to direct block simulations. The underlying multivariate discrete Gaussian model (DGM), the validity of which is tested beforehand, is put to good use to mimic the selection process at the mining stage, by offering the ability to simulate in each block a composite value located at random within the block. Finally, the paper presents the application of a scenario reduction algorithm to pick a representative subset of a few simulations to help appraise the risk attached to the downstream phases (reserve optimization, mine sequencing) of the project. The implementation presented here is for the first generation of the Scenario Reduction plugin built in Isatis software, where measuring the distance between the initial set of scenarios and the reduced set is based on Ni quantities only. Research is under way to adapt the measure to the true multivariate nature of the problem.

Jan 1, 2014

Calculations of the temperatures of metal, coke, and gas at any level in the cupola furn~ce can be carried out by means of heat balances, using data obtained from experiments with an 18 in. experimental cupola. The results can, to a certain extent, be verified by means of heat transfer calculations.The curves thus obtained, showing the variation of temperature with height in the cupola, provide a valuable picture of the heat transfer processes in a shaft 'furnace.INTRODUCTIONThe Brown Coal Research Laboratory, of the University of Melbourne, has been engaged in recent years on a programme of iron-melting tests in an experimental cupola furnace.Although the ultimate aim of this work is to develop brown coal char as a cupola fuel, most of the experimental work so far has been with conventional coke. The testing programme was designed to provide information on the effect of variables such as blast rate, metal-coke ratio, and coke size on the overall melting process, e.g. melting rate, temperature of metal tapped, and stack gas composition.However, in many cases data were obtained on conditions inside the furnace by measuring temperatures and gas compositions. The aim of the work described in this paper was to qevelop a method for using this data to obtain information on the processes taking place in the cupola.Very little research has been done on the combustion of fuels in shaft furnaces. Early work on this subject, as well as the initial stages of the Brown Coal Research Laboratory's programme, has been discussed by Evans (1959). The use of probes for obtaining information on conditions in the interior of a shaft furnace was pioneered by Belden (1913)...

Jan 1, 1963

By W. J. Reagan

Mr. Caine, members and friends of the AIME Electric Furnace Conference, as Chairman of the Executive Committee it is my pleasure to welcome you to this our fifth annual conference. I can assure you that the conference chairman and his committee have prepared a program of unusual and timely interest. Mr. Caine has spoken of the educational session. This part of our program was of unusual interest last year and I am sure that the subject of this year's discussion will prove to be just as interesting. The wide variety of subjects cover both the basic and the acid electric furnace and are in keeping with the usual high quality maintained on our programs in past years. As the papers and discussions will be published in the PROCEEDINS, you will in a short time be able to add another volume to the present series.

Jan 1, 1947

By Michael W. Lewis

The latest downturn in the world’s metal prices has forced many mining companies to focus on cost reduction and productivity improvements to remain competitive. Maintenance represents a significant part of the overall operating costs in the mining industry. A structured, proactive maintenance approach, such as reliability-centered maintenance, can achieve cost reductions and productivity improvements. Remote condition-monitoring systems are becoming commonplace because they have the potential to identify problems before failure. Detection of equipment degradation before failure will enable repairs to be scheduled, thereby reducing costs and interruptions to production. The mining industry is in the midst of uncertain times. Decreasing commodity prices, demand, head grade and capital availability along with increasing environmental requirements have put pressure on mining companies to significantly reduce costs to maintain short- and long-term viability. Corporations are looking at expansion, merger/consolidation and financial/hedging programs to achieve these cost reductions. Mines are reducing costs by eliminating all but essential expenditures, increasing production levels, reducing overtime and investing in new technologies.

Jan 1, 2000

By Henrik Saxén, Mikko Helle, Hamid Ghanbari

In this study, a process integration approach in a primary steelmaking is investigated to evaluate future operation concepts of a steelmaking site considering sustainability issues. Mathematical programming is used to study the integration of the steel plant with chemical units for utilization of available off-gases in the system, and carbon capturing and sequestration unit. Different industrial carbon utilization options are considered to find the best route of development. A multi-period optimization model is developed based on site-wide mass and energy balances by considering the availability of the fuels and by-product gases and their consumption in the production system and a conceptual polygeneration system. The objective is to reach maximum economic profit while environmental aspects of integrated system are considered for different fuel systems, alternative blast furnace reductants and implementation of new process technologies. The model can provide useful information concerning techno-environmental and economic aspects for decision-making and can estimate optimal operational condition of current and future primary steelmaking under alternative scenarios. The results of the work illustrate the potential to develop steelmaking towards more sustainable operation in the future.

Jan 1, 2015

BROWN iron ore reserves of Franklin county are being proved economical by Heavy-Media separation at the Blackburn mine of the Shook & Fletcher Supply Co. about 120 miles north-west of Birmingham. The ore occurs under a cover of ferruginous chert and gravel and these materials are also disclosed as streaks in the ore body as it is mined. Previous methods of jigging and hand sorting the ore became too expensive because of rising wages but the use of Heavy-Media separation has proved economical and is making Franklin county the most promising source of additional reserves of brown ore.

Jan 12, 1950

Prof. G. W. MAYNARD, New York City (communication to the Secretary): Prof. Christy, in his admirable paper on "The Growth of American Mining Schools," has overlooked the work done by the Rensselaer Polytechnic Institute in its department of mining and metallurgy. This oversight is naturally due to the fact that the department was, for lack of money, discontinued in 1871. It was organized by the writer in 1867, starting with ten students, who had already completed the first two years of the civil engineering course in the Institute. The course covered two years, specifically devoted to mining, metallurgy and assaying, which, in connection with the two years' drill in the civil engineering department made a four years' course. During the four years of the existence of the department, thirty-five students took the course, of whom twentyfive graduated; and of this number eight have been members of the Institute of Mining Engineers, and the majority of them have occupied high positions in the profession. The equipment of the department was, at that time, second only to that of the Columbia School of Mines. As Prof. Christy has cited other institutions which are not distinctively mining schools, but in which the ruining course was subordinate to other courses, it seems to me that the work in this line carried out by the oldest engineering school in the country may very properly be referred to. In addition to the regular mining course, a special course in assaying was given; and many young men were here prepared for positions in the mines and metallurgical works of the west. PROF. George F. Swain, Boston, Mass.: I have listened with great interest to Prof. Christy's valuable paper, but there is one conclusion at which he arrives that appears to me entirely unjustifiable, and to which I desire to take exception. Prof. Christy finds that of the total wage-earners in the United States in 1880,10.41 per cent. were employed in " trade and transport;" 20.24 per cent. in " manufactures and mechanics," and 1.83

Jan 1, 1894

By W. G. Davenport

The offgas from flash furnaces inadvertently contains dust. The dust contains 25 to 30% Cu so it must be treated for Cu recovery. This is almost always done by recycling it back through the flash furnace*. This chapter shows how dust production/recycle is included in our matrix calculations. It then discusses the effects of dust production/recycle on flash furnace industrial oxygen and oil requirements. It concludes that re-smelting of dust requires considerable industrial oxygen and fuel, so that dust production should be minimized. Recycled dust also takes the place of new concentrate in the flash furnace feed system, decreasing Smelter productivity -another reason to minimize dust production. Compositions of industrial dusts are given in Appendix VII and Table 18.3. Industrial quantities are given in Tables 2.1, 3.1, 19.1,20.1' and Appendix VI.

Jan 1, 2001

By Qing Wang

In this method the state of an open-pit mine is represented by the number of benches that are mined in each predesigned mining phase (or pushback). Consequently, a specific mining schedule can be represented by a sequence of states which starts with the topography of the mine site and ends with the ultimate pit. For a given set of mining phases all feasible states are first generated and sequences of states are then evaluated for technical and economical feasibility. The best sequence, which gives the maximum net present value (NPV), is found by applying a dynamic programming optimisation algorithm. The algorithm also optimises the cut-off grade which satisfies the mill feed requirement for each planning period. It was found that the algorithm can be used not only for scheduling but also as an effective tool for analysing the effects of mining and milling capacities and cut-off constraints on the mining schedule and the total NPV. The algorithm, which was programmed in C, was successfully applied to a large Au-Cu deposit

Jul 1, 1996

By William E. Torres

The Southern Peru Limited smelter, in Ilo, operates two reverberatory furnaces, seven Peirce-Smith converters, one Teniente Converter, two casting wheels and a single contact acid plant. The Teniente Converter was commissioned in August 1995 and was designed to smelt 744 dry metric tons (820 dry short tons) of concentrate per day. The process off-gas is collected in a water-cooled hood, cooled in a spray chamber, and cleaned in a Joy electrostatic precipitator for further treatment in the Acid Plant. This paper presents the current Teniente Converter operating practices and control philosophy. Relevant improvements and modifications to achieve a 379 day campaign without tuyere replacement and a daily average smelting rate of 862 dry metric tons (940 dry short tons) of concentrate are discussed.

Jan 1, 1998

By G. S. Hill, B. J. Huls

This paper on coarse particle recovery (CPR) summarizes a process to capture coarse particles that are not recoverable by regular flotation. Several porphyry copper operations in the world operate analogous circuits that recover non-floated copper from tailings; however, the case presented here is unique in that extensive underlying test work has allowed the authors to elucidate some fundamental principles behind recovery enhancement. This paper discusses an overview of the flowsheet that is proposed to Minera Escondida Ltda., the nature of copper in the feed to the CPR circuit, and the various unit operations within the recovery circuit.

Jan 1, 2006

By A. W. Cochardt

MOST of the current high temperature materials are precipitation-hardened alloys. These alloys are usually soft when quenched from a solution heat-treatment temperature, but become harder

Jan 1, 1958

Certain information contained herein regarding Champion Minerals Inc., including management?s assessment of future plans and operations, may constitute forward-looking statements under applicable securities law and necessarily involve risks, including but not limited to risks associated with mining exploration, operating costs, production costs, volatility of share prices, currency fluctuations, imprecision of resource and reserve estimates, environmental risks and ability to access sufficient capital from internal and external sources. As a consequence, actual results may differ materially from those anticipated in any forward looking statements. Plans, intentions or expectations disclosed in any forward-looking statements or information should not be read as guarantees of future results or events, and will not necessarily be accurate indications of whether or when or by which such results or events will be achieved. Except as required by law, Champion Minerals Inc., expressly disclaims any intention and undertakes no obligation to update any forward looking statements or information as conditions change. The historical mineral resources mentioned are strictly historical in nature and are non-compliant to National Instrument 43-101 mineral resources and mineral reserves standards, and should therefore not be relied upon. A qualified person has not done sufficient work to upgrade or classify the historical mineral resources as current National Instrument NI-43-101 compliant.

May 1, 2011

By D. Duvris

The main objective of this work was to quantitatively investigate exhaust emission levels, as related to maintenance (service) intervals, during the operation of diesel-powered equipment at an underground bauxite mine in Greece. Such emissions depend on a great number of parameters, including the type (technology) and tuning of the engine, the type of work performed as related to the engine workload, suggested maintenance intervals, the altitude, the temperature and the humidity of the atmosphere of the underground mine, the properties of the fuel, the operator's training and experience level. Necessary ventilation quantities were calculated based on exhaust gas concentration measurements, site specific relationships between pollutants and adjusted air quality indices. Diagrams comparing necessary and recommended air flow for several equipment groups featuring two engine types and for different maintenance intervals are presented.

Jan 1, 1998