Search Documents

By Robert Wamsley, W. E. Jones

ONE of the earliest problems in the life of any community is the provision of an adequate supply of water sufficiently free from all types of contamination to be suitable for domestic purposes. Generally speaking, the location of most communities is determined to a great extent by the availability of an adequate supply of satisfactory water. For a mining camp, that consideration cannot be foremost. Here, the ore takes first place, and the men who mine it must do the best they can under the existing conditions. If there is no local source of water, it must be brought from some distant source or must be found by sinking shafts or drilling wells. Fortunate indeed is the mining company that discovers a commercially valuable ore deposit beside a never failing creek full of pure water, with sufficient water rights available, because the acquisition of water in any other manner nearly always involves not only a considerable period of time but the expenditure of considerable money. The experience of Climax Molybdenum Co. demonstrates the measures that sometimes are necessary in order to provide a suitable supply of water. The Climax mine and mill are on the Continental Divide, about 13 miles northeast of Leadville. The elevation of the domestic part of the camp varies from a minimum of 11,320 ft. to a maximum of approximately 11,550 ft. above sea level, and, as is common at such altitudes, the near-by streams that might be suitable for a water supply are small and intermittent, usually flowing only during the summer months. The only streams of any size in the immediate vicinity of Climax are the Ten Mile and Arkansas Rivers. The headwaters of Ten Mile River are on the Company's property, and its water has been used for the domestic supply. The headwaters of the Arkansas River are about 2 miles distant and have not been used as a source of supply by the company. During the past 11 years of the production of molybdenum at-Climax, the number of families living there has increased from about 45 to 283, and the population has increased from about 200 to 1200 persons. Consequently, the capacity of the water-treatment facilities, and the amount of water available, had to be increased to meet the requirements of the camp. As early as 1932 it was recognized that the water in Ten Mile River would not continue to be adequate for domestic purposes and after considerable discussion it was decided to drive a drift through the major fault in an effort to find additional water. This drift was completed in 1935 and tapped sufficient water to make the supply adequate. This water was treated in a tank underground, where lime was added, and was then piped into the domestic supply lines. At about the time this line was completed, the presence of fluorine in harmful concentrations was discovered in the water. This problem was submitted to the International Filter Co. and in November 1937 a plant of its design was put in operation for treating the water to remove the fluorine. This plant proved entirely successful,

Jan 1, 1945

By Grover J. Holt

In order to provide a clear picture of the development of the sink-and-float process of concentration as applied to the iron ores of Minnesota, a few pertinent facts should be brought out concerning the ores and the products of concentration. Iron ore is primarily a cheap commodity handled in immense quantities. The price of iron ore at present, based on a natural iron content of 51.5 per cent, varies from $2.55 to $2.70 per gross ton f.0.b. cars at the mine or washing plant in Minnesota. Last year 92,000,000 gross tons were shipped from the Lake Superior district (Minnesota, Michigan, and Wisconsin) to the furnaces. Concentrated iron ores have no greater value per unit of iron content than ores that can be mined and shipped direct from the shafts or open pits. For years only the higher grades of concentrating ores could be treated and sold in competition with the immense reserves of direct shipping ore available. These higher-grade "straight wash" ores required only the simplest treatment; namely, the washing out of fine sand from coarse ore particles. As the exhaustion of the " straight wash " ore is reached, rock is found replacing part of this sand, and the ore no longer responds to the former sizing treatment. Substantial tonnages of this marginal (jig ore) remained to be treated. Because of the limitations placed on concentrates by the furnaces—namely, low price of product and minimum amount of fines—iron-ore concentration oil has been and must continue to be a one-pass process. Only an increase in price or a change in structure of concentrates allowed by the ore consumer will encourage departure from this practice. Faced with the necessity of handling large tonnages, with the limitations mentioned, iron-ore research men have found their search for new and more efficient methods of treatment seriously handicapped and removed from the field of fine crushing. Sink-and-float treatment appeared to offer the best field in coarse concentration and has been proved by several plants to be well adapted to our problem. The use of ferrosilicon as a medium solid was decided upon. In our present practice, the ferrosilicon metal, carrying about 83 per cent iron, 15 per cent silicon and 2 per cent carbon and nonmagnetics, is crushed to pass 65 mesh and used without further sizing. When mixed with water the specific gravity of the medium may be controlled to within 0.02 per cent above or below the required gravity. Table I shows examples of a change in solid content of the medium for varying gravities. the I is based on clean ferrosilicon, whereas some contamination is always present in the mill circuit, tending to

Jan 1, 1947

By Grover J. Holt

In order to provide a clear picture of the development of the sink-and-float process of concentration as applied to the iron ores of Minnesota, a few pertinent facts should be brought out concerning the ores and the products of concentration. Iron ore is primarily a cheap commodity handled in immense quantities. The price of iron ore at present, based on a natural iron content of 51.5 per cent, varies from $2.55 to $2.70 per gross ton f.0.b. cars at the mine or washing plant in Minnesota. Last year 92,000,000 gross tons were shipped from the Lake Superior district (Minnesota, Michigan, and Wisconsin) to the furnaces. Concentrated iron ores have no greater value per unit of iron content than ores that can be mined and shipped direct from the shafts or open pits. For years only the higher grades of concentrating ores could be treated and sold in competition with the immense reserves of direct shipping ore available. These higher-grade "straight wash" ores required only the simplest treatment; namely, the washing out of fine sand from coarse ore particles. As the exhaustion of the " straight wash " ore is reached, rock is found replacing part of this sand, and the ore no longer responds to the former sizing treatment. Substantial tonnages of this marginal (jig ore) remained to be treated. Because of the limitations placed on concentrates by the furnaces—namely, low price of product and minimum amount of fines—iron-ore concentration oil has been and must continue to be a one-pass process. Only an increase in price or a change in structure of concentrates allowed by the ore consumer will encourage departure from this practice. Faced with the necessity of handling large tonnages, with the limitations mentioned, iron-ore research men have found their search for new and more efficient methods of treatment seriously handicapped and removed from the field of fine crushing. Sink-and-float treatment appeared to offer the best field in coarse concentration and has been proved by several plants to be well adapted to our problem. The use of ferrosilicon as a medium solid was decided upon. In our present practice, the ferrosilicon metal, carrying about 83 per cent iron, 15 per cent silicon and 2 per cent carbon and nonmagnetics, is crushed to pass 65 mesh and used without further sizing. When mixed with water the specific gravity of the medium may be controlled to within 0.02 per cent above or below the required gravity. Table I shows examples of a change in solid content of the medium for varying gravities. the I is based on clean ferrosilicon, whereas some contamination is always present in the mill circuit, tending to

Jan 1, 1947

By Vitaly T. Borisovich

Mining economics courses have been taught in Europe for more than two centuries and in the United States for most of this century. They are the mineral industry's version of engineering economics offered by industrial engineering departments. In the 1930s, mineral economics first appeared in American mining schools. This subject goes beyond the deposit and the mine. It examines the economic aspects of mineral resources in general and the individual mineral industries in particular. In 1947, the first degrees in mineral economics were granted in the United States. There are mining and geological engineers who specialize in mining economics. But it has rarely become a separate degree program. Rather, in this country and several others, a graduate student in a mining department or school will include economics in his course work. Then the person writes a thesis or dissertation on a mining economics topic. One exception is found in Moscow at the Department of Geoeconomics of the Moscow Geological and Prospecting Institute (MGPI). To place this program in perspective, some background is needed on education in the Soviet Union.

Jan 1, 1991

By P. W. Bakarian

PREVIOUS determinations1,2,3 of the texture of magnesium and its alloys have shown only slight variations in the principal features of the structure. This investigation presents pole figures for magnesium and two of its alloys, in which differences of some magnitude will be shown. Schmid and Wassermann have considered the texture of magnesium in analogy with that of zinc-also a hexagonal lattice. Whereas the zinc texture is said to be derived primarily through basal slip and secondarily through {102}† twinning, the {102} twinning is considered impossible at the later stages of the rolling in magnesium because of its smaller axial ratio. This state of affairs appears reasonable for pure magnesium, but for alloy textures the situation is more complex. A double orientation similar to that found in zinc has been reported by J. D. Hanawalt,4 and the addition of small amounts of calcium to magnesium and its alloys to produce a double texture was noted by J. C. McDonald.5 The pole figures of this investigation, using an improved X-ray technique, show these various textures. The dependence of directional properties of rolled sheet on modifications of texture is well recognized. Correlation of physical properties with existing texture should be even more significant if quantitative valuations are attached to the various areas on the pole figures. Such a quantitative technique is developed herein. EXPERIMENTAL METHOD Two alloys were used, besides high-purity magnesium. In each case, the metal was extruded to bars 32 in. thick and hot-rolled to a thickness of about 0.075 in. It had been established previously that such a reduction was more than sufficient to eliminate the extruded structure. The rolling proceeded in the same direction as that of the extrusion, without any cross rolling. The temperatures corresponded to normal commercial practice, averaging around 600°F. A unique method of preparing the sample was developed in this work. Instead of using a flat specimen, a stem of the metal was cut out of the rolled sheet in the desired direction (rolling direction) as shown in Fig. 2. From a sheet of 0.075 to 0.065-in. gauge, the stem was cut to a square cross section with a jeweler's saw, rounded with a file and polishing paper to a diameter of 0.060 in, and evenly etched in dilute hydrochloric acid to a diameter of 0.038 ± 0.001 in. In this way, a cylinder of the original sheet with its axis in the desired direction was produced. By using this type of specimen for the pin-point pictures, any variance in the absorption of the diffracted beam at the various angular settings of the specimen, was completely eliminated.*

Jan 1, 1941

By Sidiney Nascimento Silva

O trabalho descreve os principais resultados dos testes industriais realizados na Usina Presidente Vargas, CSN, Brasil, envolvendo a adição de um catalisador à mistura de carvões, em termos da qualidade do coque e do processo da coqueria. O catalisador em questão é o produto Thermact, que possui partículas nanométricas em sua composição, fornecido pela empresa Abhitech Energycon Limited, Índia. O catalisador foi dosado e adicionado à mistura de carvões via correia transportadora, na proporção, em peso, de 1kg de catalisador para 4.000kg da mistura de carvões. Os resultados dos testes realizados nas Baterias # 1, 4A, 4B e 5 com a adição de um catalisador à mistura de carvões, sinalizaram a viabilidade técnica e financeira da sua aplicação no processo da coqueria. Os principais benefícios decorrentes da adição do catalisador foram: i) aumento potencial da capacidade de produção de coque ao redor de 10% ou, alternativamente, melhoria da qualidade do coque - aumento de 1,4% do valor médio do índice de resistência mecânica a frio do coque, DI150/15, mantendo-se o tempo total padronizado do processo de coqueificação, visando à preservação das Baterias, ou ainda, a utilização de uma mistura de carvões de menor custo, sem prejuízos ao atendimento à especificação do coque para os Altos-Fornos; b) aumento da geração e redução do consumo de gás de coqueria, GCO; iii) aumento na produção de BTX (Benzeno, Tolueno, Xileno) e redução da produção de alcatrão na Planta de Carboquímicos; iv) limpeza do sistema “PROven”, “goosenecks”, tubos de ascensão e paredes dos fornos, sinalizando a sua viabilidade técnica e econômica.

Aug 1, 2018

By James M. Barker

Marketing is the linchpin of the industrial-mineral (IM) industry. Without markets and consumers for IM products, all other associated IM activities are superfluous. The simple existence of an IM deposit does not mean that it can be exploited. A dynamic interaction between exploration (geology), mining, processing, transport, marketing, sales, and consumers is required for profits. Geology dictates the existence of a deposit, but markets dictate its development, and transportation provides the connection. This is true to such an extent that marketing commonly is called the exploration phase of IMs. Marketing is strategic and includes long-range market-development and planning activities, whereas selling is tactical and more focused on day-to-day consumer interactions. Each will help the other when properly done. Many producers of IMs have failed because of inadequate marketing skill, information, and practice. Over many years at the Montana Bureau of Mines, the many developers seeking technical assistance to find an IM deposit, but who had no marketing plan, always failed. In contrast, the few who sought assistance first on marketing, with the IM deposit to be found later, always succeeded (Richard Berg, personal communication, 1998). Marketing has many facets helped by geologists who must be aware of what marketing is attempting to do. A geologist needs to understand many aspects of IMs: location (deposits, plants, consumers), processing (specifications), transportation (truck, rail, barge, ship), competition (local, regional, national, international), substitutes, pricing, and new developments and market forces of all kinds. Some needed skills are not taught formally to geologists, so well-rounded self-education and on-the-job training are the way a geologist normally enters into IM marketing. The IM geologist generally is associated with marketing either by helping to prepare a market study or by acting on the results of one. Preparing a market study is a two-part process. The first part is relatively simple but requires a time-consuming collation of data into an IM survey (mostly past-and present-oriented). The more difficult and much more important second part entails expanding the IM survey into a market evaluation (mainly future-oriented) that emphasizes forecasting, timing, location, and specific products. A market evaluation generally boils down to formulating the right questions to ask of the right persons. One very good question to ask is, "What could be the market for this specific IM?" while thinking for yourself without excessive recourse to gossip, rumors, promoters, developers, or (at times) IM experts. The evaluation must prove that market potential exists and suggests a marketing plan. Effective marketing is an ongoing process, with the initial marketing plan modified over time, using wide and continuous input to avoid tunnel vision. Industrial-mineral markets are based either on commodity (lower-priced, basic-processing) minerals or specialty (higher-priced, value-added) minerals. IM marketing methods are either product-driven (commodity minerals), a more traditional approach, or market-driven (specialty minerals), but these are neither mutually exclusive nor is one always better than the other. Focusing too much on specialty minerals can lead to problems. A blend of commodity products with specialty products commonly lowers risk and enhances long-term profits. The highest profits occur in specialty minerals at the cost of higher risk and complexity and require intelligent marketing, versatile technical services, and creative research and development. Industrial minerals are best served by an industrial-marketing approach rather than a consumer approach. Modern industrial marketing emphasizes the consumer using the "marketing concept." The marketing concept focuses all management and operational activities on total consumer management and satisfaction similar to the total quality management approaches to excellence.

Jan 1, 1999

By Newell Alford

FORECASTS of future timber consumption in soft-coal mining are handicapped by; the lack of adequate experience records for estimating properly the timber requirements of the industry. Data were obtained from plants where records are kept or from operators who collected the information and to these were added FIG. 1.-GROWTH OF POPULATION IN UNITED STATES, FROM PEARL'S ?BIOLOGY OF DEATH." composite figures for the continental United States in 1905 and 1919 1 and for central and. Western Pennsylvania and for Illinois in 1922.2 The result, representing slightly over 928;000,000 net tons, is shown in Table 1. Some of the companies furnishing data were unable to segregate the timber into classes of use but for those who did, Table 2 shows the board feet of posts and cross bars used per ton of coal mined and the, percentage of the total timber consumed that was used in roof support. The wide variation in amounts of timber per ton of coal mined is the result of

Jan 5, 1924

By Z. Zhang, Zongshu Zou, Nan Wang

"Thermodynamic calculation is applied to make an investigation on the equilibrium phase relations and liquids of CaO-SiO2-Al2O3-FeOx system for different temperatures. The calculated results with FactSage6.1 show that the effect of temperature on the the equilibrium phase relations and liquidus of CaO-SiO2-Al2O3-FeOx system and its sub-systems is appreciable. The liquid phase regions enlarge with increasing temperature from 1573K to 1873K, while the primary phase fields reduce distinctly.IntroductionThe main oxide components of vitrified bottom ash slag are CaO, Al2O3, SiO2, Fe2O3, MgO, and Na2O, accounting for more than 90% of the bottom ash by weight[1]. During slag processing, the knowledge of thermodynamic properties and liquidus temperature in the related slag systems is highly required [2, 3], which is not yet available. Through literature survey [4-6], it is clear that the systematic information on the concerned complex slag system is scarce. So far the engineers in the field have to make assumptions of the thermodynamic properties of the simplified oxide system, without taking into consideration the interactions of the different oxide components, which hinders the development of the slag valorization and utilization. In order to provide thermodynamic properties for the application of the vitrified bottom ash, the six-component oxide system (CaO-MgO-Al2O3-SiO2-FeOx-Na2O) is highly required. A preliminary phase diagram of the CaO-MgO-Al2O3-SiO2-FeOx-Na2O system can be obtained from extrapolation of the thermodynamic functions of constituent subsystems such as CaO-SiO2-FeOx-MgO, CaO-SiO2-FeOx-Al2O3, CaO-SiO2-Na2O-MgO and CaO-SiO2-Na2O-Al2O3. In this work, the equilibrium phase relation and liquidus of CaO-SiO2-FeOx-Al2O3 system, one subsystem of the concerned complex slag system, are calculated and the effect of temperature is also discussed."

Jan 1, 2012

By J. J. Gilman

The dependence of ortho kink-band formation on crystal orientation, on temperature, and on the conditions at the ends of a specimen is described. Load-compression curves for crystals that kink are presented. The reversibility of ortho kinking is demonstrated, and motion of kink planes through crystals is shown. Finally, a phenomenological explanation of ortho kink-band formation is given. ORTHO compressive kink bands (Fig. la) were discovered for the case of metals by Orowan,1 and they have been discussed by Jillson2 and in some detail by Hess and Barrett." However, their history in nonmetallic crystals is considerably older. It is not known when they were first observed in mineral crystals, but descriptions of them may be found as early as 1885.* They were sometimes mistaken for twins.6 Mügge seems to have been first to realize their true nature and importance. He reviewed the knowledge of them for a wide variety of crystals: anhydrite, antimonite, kyanite, vivianite, gypsum, mica, graphite, molybdenite, barium bromide, cal-cite, sodium nitrate, and barite. Also, the "twins" observed by Bridgman7 in sapphire crystals resemble kink bands more than twins. The terms ortho and para kink bands have been coined in order to distinguish between two types of kink bands which seem to represent the same geometrical configurations, but which have different origins and sizes. Ortho kink bands are the usual type that form at low loads when zinc crystals are compressed parallel to the basal plane. Para kink bands form at much higher loads in highly deformed crystals. These terms refer to compression phenomena and are not to be confused with analogous tension phenomena such as tensile kink bands and deformation bands. Mügge described the geometry of ortho kink bands quite completely for kyanite crystals, Fig. lc. The geometry observed for cadmium by Orowan1 and for zinc by Hess and Barrett3 is very similar to that described by Mügge. (See Hess and Barrett for a complete discussion.) Mügge associated kinking with bending combined with basal slip. He pointed out that the kink angles

Jan 1, 1955

By R. T. Walker

GROUND waters-hot or cold-containing small amounts of the more common earth acids, such as carbonic acid, silicic acid, hydrogen sulfide, sulfurous acid and sulfuric acid, have only a very limited "solvent effect on dominantly siliceous rocks, whether of igneous or sedimentary origin, but in limestone they often form extensive cavities; and such "limestone caves" are the only openings of considerable size and continuity in rock formations that do not owe their existence directly and almost wholly to dynamic action. Limestone caves such as are developing at the present time must have been formed in all past geological ages in which limestone beds existed and where suitable conditions for the development of such caves prevailed; hence it would seem a reasonable expectation that, in the course of geological history, a certain number of ancient limestone caves must have been utilized as channels for the passage of mineralizing solutions, during portions of their course, at least, and that, in consequence, orebodies must have been deposited in such caves. Such a conception is not novel; it was proposed many years ago, but its possibilities, as explaining certain types of ore deposits, have been rather lost sight of in the development of the theory of the metasomatic replacement of rocks by minerals. It is the purpose of this article to assemble evidence to show that many of the orebodies found in limestone beds have been deposited in pre-existing caves; to discuss the criteria whereby such orebodies can be distinguished from others which have been formed along fissures and fracture zones traversing limestone, by the more common method of metasomatic replacement, analogous to orebodies in other formations; and to describe certain orebodies-particularly the "ore channels" of the Tintic district, Utah-as illustrative of the principles discussed. Limestone caves may be divided into two classes: those formed by cold, descending surface waters, which emerge again at some lower elevation as cold springs; and those formed by hot, ascending waters of deep origin or circulation, which attain the surface as thermal springs. Although these two classes are similar in many respects, there are certain characteristic and inherent differences whereby they can usually be distinguished.

Jan 1, 1928

By Richard Crowell, James Gillaspie

A concentrate biooxidation process was successfully demon­strated in the field in a remote part of northwestern Mexico. A 275 tonne (300 st) biooxidation heap was constructed using GeoBiotics' proprietary GEOCOAT™ coated concentrate process. The pyrite/chalcopyrite/sphalerite concentrate was bioox­idized in the heap for 60 days. Cyanide leach recovery of the con­centrate increased from 68% gold recovery at a cyanide consump­tion of 1.6 kg NaCN/g Au (llO lbs/oz) in the as-received concen­trate, to 94% gold recovery at a cyanide consumption of 0.37 kg NaCN/g Au (27 lbs/oz) in the biooxidized concentrate. The heap was constructed at a rate of7 tonnes (7.5 st) concentrate per hour, using typical heap leach equipment and easily scalable methods. Heap operations demonstrated that energy dissipation in the humid summer environment was easily controlled by low pressure aeration and management of solution chemistry and application. Observations of the demonstration heap appear to support the presence of reflux of moisture within the biooxidation heap.

Jan 1, 1998

Scheduling mine development and underground construction has been the bane of most mine managersÆ lives at one time or another. Even though scheduling software has developed significantly over the last 20 years, mining projects continue to take far longer than expected to complete. It would appear that possession of a gleaming 1000 activity bar chart generated by the latest project management software and plotted in multiple colours offers no guarantee at all that any of those 1000 activities will be completed on time, let alone the project as a whole. The author has earned his æmasters in disastersÆ with more than one project running over time and budget. This paper describes some of his experiences in scheduling major mine development and construction projects and the lessons he has learnt along the way. In particular, the paper examines a range of key issues that mine schedulers must take into account when planning mining projects. The paper also examines the development of scheduling software and particular advance rates used in scheduling mine development projects in Australia.

Jan 1, 2000

By Giovanni Barla, Stefan H. Boshkov

This paper examines the application of gelatin mixture models to the study of factors such as gravity effects, tectonic and residual stresses, anisotropy, physical nonlinearity, time-dependent behavior of the rock mass and connectedness of the geologic space. The technique of calibrating gelatin mixtures proposed by Richards and Mark in 1966 is applied to the particular problem considered. Similitude relationships between model and prototype are discussed with reference to the constitutive equations describing the physical behavior of the rock mass. The interaction between two openings in a linearly elastic medium, under conditions of plane strain, is used as an illustrative example with the view to describing the history of stress and deformation changes on the rock medium and lining around a slusher drift while undercuts are made in block caving. The prediction of the displacement, stress field and mode of fracture associated with a given rock structure, its initial stress field, and its physical properties is essential to rock mechanics and ground control. The basic approach is to assume the rock mass to behave as a continuous, homogeneous, and isotropic medium. The classical theory of elasticity is the simplest theory based on such a concept. Specification of the elastic constants, the initial state of stress in the ground, and the boundary conditions on stress and displacement allows one to predict stress and displacement within the body. Subsequently, provided that a criterion which governs rock fracture under various stress conditions has been established, a stability analysis of the rock structure can be performed. A natural extension of the present knowledge consists of removing some of the simplifying assumptions which characterize the analytical solutions based on the classical theory of elasticity. Complex geometry, the significance of tectonic and residual stresses, anisotropy, physical nonlinearity, time-dependent behavior of the rock mass and connectedness of the geologic space are some of the important factors which are neglected in the classical approach. A better insight into the real problem can be attained with either the finite element method of stress analysis or an experimental technique. The former has already been applied with success on several occasion 1-4 and is destined to render great service in the field of rock mechanics and ground control. The latter, which will be considered in this paper, has been used extensively in applications too numerous to be enumerated. Experimental technique involves either prototype testing, if the area to be studied is accessible, or model testing. Two- and three-dimensional photo-elastic analyses are very convenient means of obtaining the stress distribution in models of complex geometry. In general, such analyses are confined to studies of stress fields around openings which are sufficiently far removed from the surface boundary so that the stresses in their neighborhood are practically equal to those produced by an initial uniform stress field; i.e., so that gravitational effects are negligible. There are, however, many rock structures where these effects must be taken into account to attain a more realistic representation of the problem. Surface and near surface rock structures, systems of openings interacting with one another, and structural components loaded only by their own weight are some of the obvious examples. This paper was written to show how factors neglected in the usual analysis based on the classical theory of elasticity, can be taken into account when gelatin mixture models are used inconjunction with photoelastic methods. The interaction between two openings in a linearly elastic medium, under conditions of plane strain, is used as an illustrative example, with a view to describing the history of stress and deformation changes on the rock medium and lining around a slusher drift while undercuts are made in block caving. The birefringence of gelatin mixtures has been known for some time. A series of experiments were carried out by Rossi in 1910,5 but after that very

Jan 1, 1970

By T. J. Ballard

The Rickard mine in York County, S. C., named for the original owner, Alexander Rickard, was operated about 50 years as. No records are available of the quantity of corundum shipped. Pratt states, "Many tons were picked up from the surface and shipped." The mine was visited on August 6, 1943, by the author, accompanied by Gilbert W. Withers of Atlanta, Ga. Investigation of the property was begun by the Bureau of Mines after some initial work by the Mi-Cor Corp., a company organized by Gilbert P. Withers of Atlanta to explore the property. In conducting the Bureau program, 754 linear feet of trenches were dug, 110 feet of old drifts cleaned out and examined, and 38 feet of shaft retimbered.

Jan 1, 1948

By D. F. Atkins, B. A. Rogers

The constitutional diagram presented herein is relatively simple. Complete mutual solid solubility exists for an interval below the solidus line, a continuous curve with a flat minimum near 22 pct Cb and 1740°C. Upon cooling, the solid solution breaks up, except at the columbium-rich side, from two causes: zirconium-rich alloys transform under the influence of the ß-a transformation in zirconium; alloys of intermediate composition decompose into two solid solutions below 1000°C. The combined effect is the formation of a eutectoid at a temperature of 610°C and a composition of 17.5 pct Cb. The eutectoid horizontal extends from 6.5 to 87.0 pct Cb. Some age hardening effects have been observed in the zirconium-rich alloys but the positions of the solvus lines remain uncertain. IN recent years, zirconium has been produced in much larger quantities than were available previously. Correspondingly, the incentive for studying its alloy systems has increased, as the number of recent publications on alloy systems testifies. However, only a partial diagram of the Zr-Cb system has been published and relatively few references have been made to alloys of the two metals. Hodge' investigated the Zr-Cb system up to about 25 pct Cb. His data on melting points were not sufficiently numerous to distinguish with certainty between the alternatives of a narrow eutec-tic horizontal and a wide flat minimum in the solidus curve. Although Hodge considered his results on transformations in the solid state to be only tentative, he suggested that the eutectoid in the zirconium-rich alloys lay at about 625 °C and 10 pct Cb and estimated that the solubility of colum-bium in zirconium at 625 °C was near 6 pct. According to Simcoe and Mudge,2 less than 0.5 pct Cb is soluble in zirconium at 800°C. These authors observed an increased strength in both the 0.5 and I pct Cb alloys made with hafnium-containing zirconium. According to Keeler,3 the strength of zirconium is increased by addition of columbium to a content of at least 3 pct. Keeler' also observed a maximum in hardness at about 10 atomic pct Cb and commented on the brittleness of alloys of this composition. Anderson, Hayes, Rober-son, and Kroll5 investigated the tensile properties of Zr-Cb alloys containing 5.1 and 12.9 pct Cb at room temperature and at 343°C. The 12.9 pct alloy had a high tensile strength at room temperature but also a low percentage of elongation. All alloys had high elongation at 343 °C. Littona measured strength and elongation values of annealed alloys containing up to 27.5 pct Cb and found low elongation values for all of the alloys of high columbium content. Some observations on the resistance of Zr-Cb alloys to corrosion in water at high temperature have been published by Lustman, De Paul, Glatter, and Thomas' who found that additions of columbium up to 1 pct had only a minor effect on the corrosion resistance of zirconium. Preparation of the Alloys Raw Material: Zirconium of a relatively good grade was available for making the alloys. It was obtained as scrap pieces that had been left over from an operation that included production by the iodide process, melting under a protecting atmosphere, and fabrication to plates. The individual pieces had hardness values of 24 to 32 Ra and a typical analysis is shown in Table I. The columbium also was scrap trimmed from sheets. It was furnished by the Fansteel Metallurgical Corp. and had a high ductility but its analysis was known only approximately. The metal probably contained about 0.5 pct Ta, perhaps 0.25 pct C, and a few hundredths percent each of iron, silicon, and titanium. Melting: The alloys were melted in a tungsten-electrode copper-crucible arc furnace similar to units that have been described recently in the metallurgical journals.'.' The crucible of this furnace is provided with a cavity in which a getter charge can be melted before the melting of the alloy charges. Hardness measurements on the ingots indicate that the getter charge takes up a considerable fraction of the oxygen and nitrogen from the helium atmosphere of the furnace. The alloys used in the investigation are given with their intended compositions, hardness, and melting points in Table 11. Fabrication: All alloys of the Zr-Cb system appear to be amenable to fabrication. At least, all of the compositions listed in Table II could be reduced to wires in a rotary swaging machine. The starting material was either slabs cut from ingots and ground by hand to rough cylinders or narrow strips trimmed from sheets made by cold rolling slabs. However, not all of the alloys could be fabricated satisfactorily by the same method. From 0 to 4 pct Cb and from 20 to 30 pct Cb or more, the alloys could be swaged cold from ¼ in. cylinders to 0.80 mm wires with only one intermediate annealing, sometimes with none. From 40 to 90 pct Cb, the alloys were difficult to swage either hot or cold but could

Jan 1, 1956

By R. C. J. Goode, W. S. Rapson, W. R. Lawrie, L. W. P. Van Der Bosch

W. R. Lawrie (Member): As all the Institute members present are aware, the Ninth Commonwealth Mining and Metallurgical Congress was held in Great Britain from 3rd to 24th May, 1969. The Congress opened in London and the first week was devoted to technical sessions. Several receptions and other forms of entertainment were held in the evenings. The Congress was attended by some 1 200 delegates, many of whom were accompanied by their wives. As can be imagined a large organisation was needed to cater for all the whims of these delegates, to arrange accommodation and to provide transport for the technical trips, for the receptions and for the sight-seeing tours. Papers presented at the technical sessions proved of great interest. It was stimulating to hear of the developments taking place in the various branches of mining and metallurgy. The discussions which developed between men from so many different countries were thought provoking, led to new friendships and most of us made valuable contacts for the future. There were 141 papers presented in the one week. They were given in four separate halls with two, three and sometimes four papers coming up for discussion in each of the three sessions per day in each hall. Among the more interesting subjects were those concerning off-shore drilling and the facilities for production of petroleum and natural gas. Beach mining at Consolidated Diamond Mines drew a large audience. Automation, mechanization and other technical developments were well described and we were brought up to date with modern techniques of mineral prospecting. There was general discussion on the future of the mineral industries together with comments on the consumption and price trends of these metals and minerals. The future of uranium, of vital interest to us in South Africa, came in for much debate. During the first week, besides attending the technical sessions and seeing some of the sights of London, we were royally entertained. There was a banquet, attended by some I 400 people, where we were welcomed by Princess Alexandra, a reception by H.M. Government in the Banqueting House, and we were entertained at the House of Lords on a terrace overlooking the bustling and rather muddy river Thames. Then there was the visit to the Glyndebourne Opera. It is only in London that at 3 o'clock of an afternoon, nearly 1 000 people all togged up in dress suits and long dresses and carrying packets of sandwiches for supper could arrive at a station to catch a train, and not even cause a stir of interest or a raised eyebrow! This is the way we travelled 60 miles to the opera from London. Surely there can be no more picturesque or romantic a setting for an opera than this large 400-year old red brick manor house nestling in the green valleys of the unspoilt Sussex countryside. It was a glorious evening and though we returned somewhat late and tired, not one of us would have missed this experience. After the first week in London there was a choice of tours of one week to London and the Home Counties, Cornwall, a Geological tour to Scotland, South Wales, and North England. These were followed by further one week tours to Yorkshire and Lancashire, Scotland, West Country and Midlands, a Geological tour of Wales, and a Mining and Geological tour to Jurassic Iron Mines. We then returned to London for the final session and closing banquet. Post-congress tours were arranged to Europe and to Ireland. It was a wonderful Congress, a great experience, we made many friends and may there be many more congresses! . L. W. P. van den Bosch (Member): Much has already been said in appreciation of the excellent organisation and arrangements made for the delegates who attended this Congress. This report is confined to a brief discussion of the personal impressions gained from the papers presented and the technical visits attended. The papers covered a wide variety of subjects ranging from highly theoretical observations to practical descriptions of operations. There were three main themes, VIZ: 1. The attention given to research and its forceful application to practical operation. 2. A steady development in mechanization and automation leading to savings in manpower. 3. Improvization, modernization and adaptation of exisitng facilities. Thoughts on these themes can best be illustrated by comments on some of the industries visited. COAL The National Coal Board (N.C.B.) has been most progressive and all of us have heard of the Bevercotes Colliery with its completely automatic mining and coal handling equipment. This was not, unfortunately, on show but there is no doubt that this is one of the greatest advances in coal mining leading towards continuous production. Coal in Britain is fighting for its life against oil, North Sea gas, imported gases and nuclear power. Output is dropping, the less efficient collieries are closing down and efficiencies are steadily rising as the following tabulation indicates: In 1931: 1 million men produced 300 million tons of coal In 1947: 0.7 million men produced 230 million tons of coal In 1968: 0.4 million men produced 160 million tons of coal

By Emile D. L. Rienks

We have studied the interaction of NO with the quasi-hexagonally reconstructed Au(100) surface. Using variable temperature scanning tunneling microscopy we have observed formation of the unreconstructed phase of Au(100) after NO exposure. This NO adsorption induced phase transition is observed in a window of temperatures around 170 K. Under the same conditions, CO and O2 cannot drive the phase transition, suggesting weaker interaction. Thermal desorption spectroscopy experiments provide an estimate for the strength of NO chemisorption on Au(100) of 57 ± 4 kJ mol-1.

Oct 1, 2003

By Jack K. Lemley

This paper will provide an update of the Channel Tunnel Project including a discussion of the overall legal structure and management organisation. It is important to understand the mission that TML, as a design/build contractor, has undertaken and how the various interfaces have evolved between the other entities involved in the project. The paper will describe the evolution of the management organisation and the approach to completion of our contract, recapping the historic events and moving into a projection of how we will manage the completion of this very large transportation system.

Jan 1, 1991

By John D. Welsh

Heap leach pad liners are important to leach operations for maximizing recovery of gold bearing solutions and minimizing potential environmental impacts. Liners must be designed so that they can be built economically, but careful attention must be paid to the potential for liner damage during installation or placement of ore on the completed pads. This paper summarizes field experience gained on several leach pad construction projects in Nevada. Both soil and synthetic membrane installations are discussed. Emphasis is placed on principles that should be considered during design to provide economical and practical leach pads.

Jan 1, 1987