Search Documents

MR. MARGOLF: Our final speaker this afternoon before we have an opportunity for some questions for the members of the panel, is a gentleman who has spent more than 40 years in the newspaper industry. He started out as an office boy while he was still in high school. He worked his way through college working for a newspaper in Lexington, Kentucky where he graduated from the University. He has a long association with the Albuquerque Tribune but what brings him here today is in his position as editor of The Rocky Mountain News which is certainly one of our largest circulations. I think it is the largest circulation newspaper in the Rocky Mountain states. Ralph Looney, in that

Jan 1, 1982

Papers in Classes A-Metal Mining, B-Milling and Concentration, H-Indus¬trial Minerals, and I-Mining Geology are distributed in MINING TECHNOLOGY, which is issued every other month. Papers in Classes C-Iron and Steel Division, D¬-Nonferrous Metallurgy and E-Institute of Metals Division are distributed in METALS TECHNOLOGY, which is issued twice quarterly. Papers in Class G-Pe¬troleum Division are distributed in PE¬TROLEUM TECHNOLOGY, which is issued every other month. TECHNICAL PUBLICA¬TIONS in Classes F-Coal Division, J¬-Mineral Industry Education Division, K¬-Mining Administration, and 1-Geophysics, are issued as separate pamphlets. Contributions are papers that when printed or mimeographed are available but only on request.

Jan 1, 1943

By P. Somasundaran Discussion by Knut L. Sandvik

Knut L. Sandvik (Mining Engineer, Mineral Dressing Laboratory, Technical University of Norway, Trond-heim, Norway) — The discovery that adsorption at solid-liquid interfaces is influenced by adsorption at other interfaces may prove very fruitful in the further development of flotation theory. Having reached the same conclusions as P. Somasundaran in some experiments with amine hydrochlorides, I would like to offer more direct evidence of the interfacial adsorption mechanism based on surface tension measurements and adsorption studies.' This evidence was derived from flotation tests carried out in a Hallimond tube at neutral pH and 60°C. The amount of amine solution and quartz surface were chosen to insure measurable concentration changes during flotation due to adsorption. Adsorption data for

Jan 1, 1969

By Philip D. Pearson

IN recent years, there have been many changes in mining operations in the Lake Superior district. To follow these trends on the Menominee Range of Michigan, information has been assembled from all of the iron mining operations in the area. There are 15 operating underground mines in the Iron River-Crystal Falls area of the Menominee Range. Within the past two years, two idle properties were re- opened and are now producing, and a third and fourth are being reopened. Also, there are two siliceous openpits operated by independent companies outside this immediate area. Six companies operate the underground mines, employing some 1850 employees. Table I shows pertinent facts about these properties.

Jan 4, 1951

By B. Erdem, N. Çelebi

An important problem associated with tandem dragline systems is that of matching the productive capability of individual draglines in the combination. In this paper, a dependence mechanism among draglines in a tandem system is described, and possible consequential problems in a poorly-matched system are defined. The rate of linear advance and the cost of stripping are determined as two major indications for an efficient operation. The proposed decision criteria and the underlying mechanism to select a synchronous couple are introduced and used in simulating tandem dragline systems. The developed model is tested on a hypothetical strip mine where pullback stripping is applied with a tandem dragline system.

Jan 1, 1999

By Kaushik Dey

Bord and pillar is the most predominant method of wining of coal in Indian underground coal mines. Development heading in coal mines often encounters roof stability problem and results in roof overbreak. Research on this reveals that the blast-induced ground vibration may have significant contribution in roof overbreak, especially, when solid blasting is carried out in the bord and pillar method. Solid blasting, in general, is associated with higher charge confinement due to lack of free face and generates higher ground vibration, which in turn results in excess overbreak.

Jan 1, 2008

Jan 5, 1950

By William C. Alden

A great landslide occurred on June 23, 1925, in the valley of Gros Ventre River, about 35 miles south of Yellowstone National Park (Fig. 1). The relations of the north-easterly dipping rock formations of the slide scarp and of the dam formed by the slide are shown in the diagrammatic cross-section of the valley (Fig. 2). This generalized section is based on unpublished maps and notes by Eliot Rlackwelder, in the files of the IT. S. Geological Survey. Heavy rains and melting snow in the Gros Ventre Mountains had saturated clay layers in the Carboniferous strata, which dip toward the valley at angles of 18" to 21°, consequently an enormous mass of rock at the end of the north spur of Sheep Mountain became loosened and, on the afternoon of June 23, slid suddenly down into the valley. Within a few minutes this mass of debris—estimated as 50,000,000 cu. yd.—carrying

Jan 1, 1928

By Carter LC

Following the perception by the Groote Eylandt Mining Company of a need to further beneficiate a fines product, and preliminary metallurgical testing to demonstrate the feasibility of such beneficiation, a comparison was made of the various configurations of cyclonic heavy medium separators available. This comparison consisted of (i) a pilot plant test in which a dynawhirlpool (DWP) and a pump fed cyclone were compared, and (ii) a survey of operating plants using the systems under consideration. Little metallurgical difference was found-between the different systems. The gravity fed cyclone configuration was finally chosen based on a particular need to minimise degradation of ore and on a desire, in so isolated a location, to use established and locally supported technology.

Jan 1, 1987

The global mining industry will always face significant challenges. Some, though, are bigger than others. What do you consider the major challenges facing the mining industry as a whole and SME in particular? Without a doubt, the major issue in both coal and metal/nonmetal mining industries is the ?graying? of the workforce in all aspects of mining. As the baby boomers continue to age, valuable experience is being lost by industry, government and academia. And there is the potential for SME to lose some of its membership. Now with that said, I should note that, despite the aging of the workforce, SME membership continued to grow by 7.1 percent during 2011.

Jan 1, 2012

By Robert Hopler

CHAPTER I. DEFINITIONS AND CLASSIFICATIONS. Definition of Explosives. SECTION 1. The term “Explosive” or “Explosives” whenever used in this ordinance, shall be held to mean and include any chemical compound or mechanical mixture that contains any oxidizing and combustible units, or other ingredients, in such proportions, quantities or packing that an ignition by fire, by friction, by concussion, by percussion or by detonator of any part of the compound or mixture may cause such a sudden generation of highly heated gases that the resultant gaseous pressures are capable of producing destructive effects on contiguous objects or of destroying life or limb, and includes all the articles specifically mentioned in Section 3 herein, and all other similar articles

Jan 1, 2013

By C. M. Diaz, S. W. Marcuson

In the late 19th century, the discovery of rich nickel-copper sulfide ore bodies in Sudbury and the need for tonnage quantities of the metal to be used in nickel steel armor provided the foundation for establishing the Canadian nickel industry. For almost 50 years, International Nickel was the key player. In 1930, Falconbridge Nickel entered the field. These two companies remain the key Canadian nickel producers. This paper discusses the factors that have influenced the evolution of nickel smelting processes. The initial Sudbury ore smelting and nickel copper separation technologies were imported from abroad. It was only in 1937 that International Nickel established a process research laboratory in Copper Cliff The explosive post WW II industrial development created a strong demand for a broader variety of nickel products. For both International Nickel and Falconbridge, R&D became an essential business tool to succeed in the new market scenery. In the last few decades, new technologies were developed and commercialized to respond to the raising cost of energy, society pressing environmental concerns, the advent of nickel laterites as an important source of new metal, the incorporation of new nickel producers to the market, and, therefore, the need to increase productivity. Canada thus became an important exporter of technology. In this paper, the authors review this history with the objective of highlighting the forces that have triggered the most important changes in Canadian nickel smelting.

Jan 1, 2005

By Robert E. Ogilvie, Zvonimir Ban

Oxidation experiments were conducted above 600°C to investigate the oxidation products formed on the surface of MoSi2. Results are presented which indicate that minor iron impurities play a key role in the oxidation behavior of MoSi2 above 600 °C. Based on considerations of the crystal chemistry of the oxidation products, MoSi2 with rhenium and iron additions was found to be resistant to oxidation in the pesting temperature range. AS early as 1914, Honigschmidtl observed that some silicides of molybdenum exhibited high resistance to oxidation at elevated temperatures. This fact did not arouse much interest until 1950, when Kieffer and cerwenka2 examined this property in more detail. They found that Mo-Si alloys with approximately 70 pct Mo (by weight) could be heated to 1600°C in an oxidizing atmosphere without any significant damage. The surface was found to be protected by the formation of an extremely thin silica glass layer which had no tendency to spa11 during subsequent thermal cycling. In 1955, Fitzer3 discovered that even solid bodies made of MoSi2 completely oxidized within a relatively short time when exposed to the air in the temperature range from 300° to 600°C. To describe this phenomenon he proposed the name "molybdenum disilicide 'pest' ", clearly analogous to the previously observed "tin plague" ("tin pest") which, however, arises as the result of a phase transformation. Studies performed by Fitzer and, in particular, one published recently by Berkowitz, Blackburn, and Fel-ten,' comprise the most extensive research to date on the pest phenomenon in MoSi2, as far as the fundamen- tal mechanism of the process is concerned. The first of these studies revealed the existence of a crystalline phase which appeared at the surface at 750°C and dissolved in the glassy silica layer at 1150°C. The logical assumption was that this phase was some reaction product of MOO3 and SiO2. The formation of a reaction product of this type seemed probable since it had been mentioned by Glemser and Lutz6 in a paper describing their studies of molybdenum oxides; however, this assumption was later disproved.8 It is our belief that information concerning the exact nature of this crystalline phase may be important for a better understanding of both pesting and the protection mechanism. Therefore, since the only available general description of the pest phenomenon was that of Fitzer, it was decided to reproduce his experiments. These experiments established that, in addition to the "pest" and "nonpest" temperature range, an intermediate region exists between 600" and approximately 650°C. This region is characterized by the appearance of a variable amount of yellow to orange colored crystals. The electron-beam microanalyzer was used to qualitatively determine their composition. Iron and molybdenum were found to be major constituents. This result can be explained based on the following facts: 1) iron, according to literature data,* is the most common impurity in molybdenum powder, and its content can be as high as 0.25 pct; 2) technical silicon powder usually contains iron; 3) steel ball mills are often used for the crushing and grinding of MoSi2. In order to clarify the exact role of iron, it was deliberately added to a stoichiometric mixture of molybdenum and silicon. The observed results corroborated the previous experiment, proving that iron (probably as some silicide phase) concentrates along the grain boundaries. I) EXPERIMENTAL PROCEDURE A) Oxidation of MoSi2 with Iron Additions. 1) Specimen Preparation. Specimens were prepared by both

Jan 1, 1967

By Barry K. Johnston, Norman W. Bainbridge, Neville C. Lockhart

CSIRO and its collaborators have developed a major R & D project on dewatering of coal. This involves sub-projects on (i) the fundamentals of coal-water associations; (ii) reducing the variability of product moisture levels from small coal centrifuges; (iii) process mechanisms and optimisation for fine coal dewatering; (iv) pilot scale testing, engineering development and innovation. Results from each of these sub-projects are presented, and the pilot facility incorporating a vacuum filter, belt press, membrane press, hyperbaric filters and centrifuges, is discussed. The vacuum filter and membrane press can be configured for electric-field assisted dewatering, which provides substantial enhancements in the rate and degree of dewatering for fine coal, coal tailings, and other suspensions.

Jan 1, 1995

By J-F. Turgeon, Y. Pépin, G. Hudon

The high temperature hydrochloric acid leaching of titanium slag in the QIT upgraded slag process (UGS) creates a harsh environment for materials of construction. Because of their excellent chemical and heat resistance, furan mortars are a key component in the lining system of the UGS pressure leach reactors. Similar products coming from different manufacturers have however shown unequal performances in service. In some cases, cracking of the brick lining has occurred during curing of the mortar. This study was initiated to investigate the impact of the curing conditions on the properties of carbon filled furan mortars. Laboratory tests were conducted to assess the effects of temperature and exposure to water and HCl solutions on mortar shrinkage and mechanical properties (tensile, compressive and bond strength). Three commercial furan mortars that have been used in the UGS leach reactors were thus characterized. Mortar properties were found to vary significantly among the products tested. Moreover, the curing conditions were shown to have a significant impact on mortar shrinkage and mechanical strength. The experimental findings provide explanations for the unequal performances of the mortars in service and for the problems of brick lining cracking that occurred in the UGS leach reactors. This study demonstrates that excessive mortar shrinkage compromises the integrity of a brick lining system.

Jan 1, 2004

By John M. Crowl, L. E. Sawyer

5.3-1. General Public Resistance to Strip Mining. Surface (strip) mining is the oldest recorded method of extracting coal and other minerals from the earth. This method of mining completely alters the topography of the earth's surface, leaving an area of more or less parallel ridges or of peaked mounds of the materials which overlay the mineral seam. It destroys all original vegetation and provides materials for new type soil. During the early years the acreage mined by this method was small, land was plentiful, and with a growing young nation no thought was given to the restoration of the disturbed areas to some form of productive use. Early in the present century the development of steam shovels and drag-lines made it possible to remove thicker overburden to recover the products. With the deeper digging, the size of the disturbed areas increased. With this increase in the size of equipment and the improvement of blasting techniques, mining was expanded into more prominent locations and to areas of more valuable land. The more progressive operators became aware of the need to reclaim those areas for some productive use. Electric shovels with capacities of up to 200 cu yd and draglines with capacities of 145 cu yd, capable of uncovering products over 100 ft below the surface, are now in use. Combined with the increase in the size of equipment, the expansion of contour mining or rim stripping in the mountainous areas has focused public attention on the need for a sound reclamation program for all disturbed areas. APPEARANCE. After mining, the areas consist of varying percentages of rock, shale, slate, and soil material devoid of all plant and animal life. Unless a definite reclamation plan is carried out, many of the mined areas will remain bare for a period of years. The topography of the area is completely altered. What may have been level to rolling land in cultivation, in grass, or in timber is thrown up into a series of ridges or mounds.

Jan 1, 1968

By D. L. Martin

The study of cobalt-platinum alloys has been of interest since they represent a class of permanent-magnet material in which the disorder-to-order transformation plays a controlling role. The magnetic properties of alloys in the range 40 to 60 at. pct have been found to be greatly influenced by composition and heat-treatment. The peak properties of 4700 coercive force and 9,000,000 gauss-oersteds energy product were obtained by controlled cooling and aging. These high values combined with ductility and machin-ability give the alloys useful characteristics although their high cost limits their application. THE cobalt-platinum alloys have been of interest in the study of permanent-magnet materials ever since the discovery by Jellinghaus that they had unusually high coerceive-force values.' The high coercive force was associated by Jellinghaus with the disorder-order reaction which occurred in these alloys. This was later verified by Gebhardt and Koster in a detailed study.2 An investigation of the structure, mechanism, and kinetics of the disorder-order transformation and resulting property changes in cobalt-platinum alloys has been in progress for some years. Certain phases of this study related to equilibrium rela- tions, and to the mechanism and kinetics of the ordering reaction have been published previously.3-5 In this paper, the results of the processing and heat-treatment studies on 40 to 60 at. pct CO alloys are presented. The magnetic properties have been found to be influenced greatly by the composition, by the cooling rate from the disordering treatment, and the final ordering time and temperature. Coercive force values, Hc, of 4700 oersteds and energy values, (BH)m, approaching 9,000,000 gauss-oersteds have been obtained by controlled cooling and ordering. PROCESSING OF THE ALLOYS The composition range of interest for permanent-magnet properties centers around the equiatomic composition Copt. In this region the alloys are dis-

Jan 1, 1959

By Harry Roe

THE power drag scrapers and the slackline cableway excavator have been called "long-range excavators." Broadly, their field of usefulness is restricted to work in which their long range of action permits them to operate economically, and which other, possibly more conventional, excavating units cannot do. Both of these machines dig or lift material and transport it to a clumping point. They combine these two functions in a single machine, nearly always in a single straight-line motion. FIG. I.-SIMPLE FORM OF POWER DRAG SCRAPER. The purpose of this paper is to examine the important features that distinguish the machines in this group from each other, as well as from other groups.

Jan 1, 1937

[NORTH AMERICA UNITED STATES Alabama BIRMINGHAM BURROWS, WILLIAM C. CORD, RICHARD H. COSTON, OTIS D. JR. FAIRHOPE RUFFLES, WILLIAM R. HUNTSVILLE WAGGONER, JERRY B. MOBILE PETROUTSON, PETER C. SELMA JONES, JAMES J. JR. UNIVERSITY CUDWORTH, JAMES R. JONES, WALTER B. RICHARDS, EDWARD F.]

Jan 1, 1961

By R. P. Carreker, R. W. Guard

True stress-true strain data are given for nominally pure molybdenum (99.95 pct) over the temperature range -196° to 1540°C (0.027 to 0.63 T/T). Strain rate sensitivity was determined by rate change tests and stress relaxation tests. Inhomogeneous yielding and strain aging effects were observed. The yield stress and tensile strength depend markedly on temperature below 400°C and are insensitive to temperature in the range 400' to 800°C. The ductile to brittle transition range is +25O to -25OC. Strain rate sensitivity and stress relaxation effects are very large near room temperature. THIS report presents data which were obtained as a part of a continuing program designed to document the deformation behavior of nominally pure metals over a wide temperature range.'" This research program is rooted in the conviction that sufficient tensile and creep data of appropriate quality and detail does not exist to provide precise phe-nomenological descriptions of the deformation behavior of pure metals as a function of temperature, strain rate, and grain size. Such knowledge is needed to provide a firm base for alloy design and an experimental framework to which theories of deformation must conform. These data also complement a parallel exploratory program investigating the properties of refractory metals, including molybdenum, and their alloys. Several important reviews and research reports dealing with the tensile properties of molybdenum as a function of temperature have appeared."-lo To a great extent the work to be reported in the present paper parallels that of Bechtold and of Pugh. The authors' results are in general agreement with those of Bechtold and Pugh. The principle differences be- tween the present experiments and those published previously are as follows: 1—Wire specimens prepared from arc cast molybdenum were used in the present experiments, bar specimens were used by others. Pugh used arc cast material while Bechtold's most extensive results" were obtained on powder metallurgy specimens. 2—Several different grain sizes were tested in the present experiments. 3—The testing range was extended to cover from -196°C to 1570°C (0.027 to 0.63 T/Tm). 4—The combination of wire specimens, high speed autographic recording, and a stiff testing machine permitted more detailed study of initial yielding. The principle contribution of the present paper is the demonstration of the relatively consistent mechanical properties of nominally pure arc cast molybdenum specimens of differing metallurgical history. Bechtold and Scotts have shown that arc cast and powder metallurgy molybdenum samples have comparable tensile properties in the range —75" to 200°C when processed to have the same re-crystallized grain size. Material The molybdenum used in this investigation was supplied by the Climax Molybdenum CO. Its metallurgical history is outlined in Table I; the final products were 0,030 in, diam wire specimens annealed at 1100' and 1375°C and 0.060 in. diam wire

Jan 1, 1957