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Some years ago the open Hearth Committee of the Institute reached the conclusion that the reading of "set" papers tended to preclude the specific and detailed discussion of specialized problems of current interest to those operating steel plants. As an innovation the Committee distributed in advance of the meeting in May, 1927, a questionnaire containing a list of 27 topics involving operating problems. The subsequent discussion of the questions, participated in by 37 members, was a conspicuous success. Semiannual meetings have been held since; and at the conference of November, 1929, at Chicago, 131 men were present and the minutes comprised a book of 133 printed pages, thereby, indicating the growing value of the conference in the eyes of both the metallurgists themselves and the companies that employed them. With this example in mind, the Directors felt that definite advantages would accrue to a similar conference to be participated in by smelter officials and metallurgists engaged in the operation of copper reverberatory furnaces. The settlement of the Carson litigation, which for several years had virtually stopped public discussion of reverberatory practice, offered an opportune time for launching the scheme. Although the Conference may become largely self-financing in the future, some funds were regarded as necessary to conduct the first meeting. The members of the Rocky Mountain Income Committee, in view of the fact that copper smelting was essentially an activity of the Rocky Mountain area, recommended the project be, in effect, underwritten by the Fund, and the directors approved an appropriation for this purpose. Invitations were extended to high executives of the various-companies interested to send representatives to an initial meeting to be held at Salt Lake City, May 26-27. The response was enthusiastic. Twenty-three metallurgists representing 12 different plants were present to discuss the comprehensive-program relating to construction and operating phases of reverberatory smelting. It was understood that the record was not to be included in the regular publications of the Institute but that it would be prepared for private distribution among the participants and the officials of their companies. That the exchange of views and experience was no less instructive and stimulating than it was frank, full and informal is indicated by the following transcript of the minutes of the meeting.

Jan 1, 1930

By Kenneth G. Skinner

Diatomite, also known as diatomaceous earth, diatomaceous silica, kieselguhr, and moler, has been used extensively for many years, but only during the past two decades has it become an important industrial mineral. United States sales for 1.936-38 totaled almost 280,010 tons,7 but relatively little (with the exception of that sold by an Oregon company affiliated with a larger California company) was sold by Pacific Northwest producers. In attempting to develop some of the many Pacific Northwest diatomite deposits, these producers have been handicapped by lack of published technical information regarding processing methods and the suitability of different deposits for specific uses. To determine some of the physical and chemical properties of known Pacific Northwest diatomites, the present investigation was started in 1938 by the Bureau of Mines in cooperation with the College of Mines, University of Washington. Figure 1 shows the location of deposits sampled. Because most relatively pure diatomites can be used as concrete admixtures or as inert fillers in rubber, paints, and plastics, this investigation concentrated upon determining some filter-aid characteristics and their relationship to other physical properties. A filter-aid is a powdered material that, when added to solutions to be filtered, improves flow rate, filtrate clarity, or both. Some chemical analyses also were made.

Jan 1, 1944

By Harold S. Davis

SURROUNDING the nuclear core of an atomic energy plant there are usually one or more thick walls of concrete, as required to protect instruments and personnel from the harmful effects of nuclear radiations. Sometimes these massive walls are of ordinary concrete weighing about 150 pcf. To reduce wall thicknesses, concrete weighing 200 to 350 pcf may be used. Such high densities are obtained by using natural aggregate processed from heavy ore, or by using steel slugs or iron shot in concrete. Mix data for a number of high-density concretes are summarized in Table I.1 High density at low cost is of prime importance in shields designed to absorb gamma rays. On the other hand, biological shields located near the reactor core must attenuate neutrons as well as gamma rays. In general, a biological shield should contain: 1) heavy elements to slow down high energy neutrons and to absorb gamma rays, 2) either light elements or hydrogenous materials to moderate neutrons of intermediate energy, and 3) materials to absorb neutrons once they have been slowed down to thermal energies. Some shield materials, iron and water for example, are effective in one or more of the above ways. On the other hand, some otherwise excellent shield materials have certain undesirable radiation properties that limit the ways or number of places they can be used. For example, when iron absorbs neutrons it emits secondary gamma rays of high energy. On the other hand, boron absorbs neutrons avidly without producing high energy gamma rays. In spite of its high cost, boron is sometimes used in concrete to minimize production of secondary gamma rays. In some shielding applications it is necessary to avoid materials that become radioactive when subjected to neutron bombardment, continuing to give off high energy gamma rays for long periods after being removed from a neutron field.

Jan 5, 1957

By K. J. Boser

"Medium Voltage (MV) metal clad switchgear is referred to as the voltage class from 2.4 kV to 38 kV. Technological advances in circuit breaker designs over the last 20 years have given rise to retrofit options in lieu of complete replacement for older outdated circuit breaker technology. This paper examines the four MV breaking techniques that exist in industry and investigates various retrofit versus refurbish options for switchgear modernization and life extension. IntroductionThe life extension and upgrade of medium voltage circuit breakers is becoming an increasingly important issue in today’s modern industrial facilities from both a reliability and safety standpoint. Unscheduled downtime, loss of production, and plant safety issues are just some of the concerns that need to be addressed with aging switchgear. A thorough examination of the available breaking mediums allows an informed decision to be made when the time comes to assess equipment performance. If you look back over the history of medium voltage breakers, you will find that there have been four breaking techniques developed and widely used:• air magnetic;• minimum oil;• vacuum; and• SF6.Many facilities that were constructed 25 to 30 years ago relied on air magnetic or minimum oil circuit breakers in their distribution systems. At the time, these were the only “tried and tested” options and they afforded good service. Since then, however, newer technology has given us the vacuum and SF6 mediums which have both proven their reliability and monopolized the market. All the methods have their particular place in industry and what follows is a summary of the advantages, disadvantages, and chronological development of each breaking technique."

Jan 1, 1998

By R. L. Huntington, Frank P. Vance, George F. Russell, Robert Thompson

With the advent of higher pressures in the operation of natural-gas transmission lines, the removal of water vapor from the gas has become increasingly important in order to prevent condensation or formation of gas hydrate from slowing down or stopping the flow of gas. Intelligent design of these dehydration or gas-drying plants has been hampered through the Iack of experimental data on the water vapor content of natural gas at elevated pressures. In view of this need, this present investigation was sponsored by the Southern Natural Gas Co. in the Chemical Engineering laboratories at the University of Oklahoma Research Institute. Experimental results were obtained on the water-vapor content of natural gas up to 2000 lb. per sq. in. at atmospheric temperatures. The water content at 2000 lb. is approximately two thirds as much as it is at 1000 Ib. Deviations from the ideal gas laws vary directly with pressure and indirectly with temperature. Introduction The removal of water vapor from natural gas is an important operation in connection with the production and transportation of this commodity because: I. Liquid water accelerates internal corrosion of a pipe line. 2. Accumulation of water at low points in a pipe line reduces markedly its capacity. 3. Gas hydrates, icy snowlike growths, form readily under high pressure in the presence of the lower hydrocarbons and water, often plugging up the pipe line. In order to design dehydration plants for stripping the gas of its water content, it is essential that the engineer. have a knowledge of the saturated or equilibrium water-vapor content of the gas to be processed. With the gradual increase of operating pressures around gas-producing wells and pipe lines, it was observed that the quantity of water recovered from dehydration plants or condensed in colder lines was considerably greater than had been expected from calculated contents, based on vapor-pressure data taken from steam tables. This observation prompted a number of investigators, for instance, Laulhere,3 Dea-ton,l and Hammerschmidt2 to carry out experimental work at pressures up to 600 lb. per sq. in. in order to determine quantitatively the water content of various gases. Sage, Lacey, et al.4,5 have recognized more recently the need for such data at higher pressures, but their work was done at temperatures of 100ºF, and higher. Since hydrate formation usually, if not entirely, occurs at temperatures below 100ºF., the present investigation was confined to the . lower temperature range at pressures from 600 to 2000 lb. per sq. in. gauge.

Jan 1, 1945

GEO. F. COMSTOCK,* Niagara Falls, N. Y. (written discussion?).-This interesting paper throws additional light on a question about which differences of opinion have apparently existed in the past, and the writer would like to record in this connection the agreement of his experience with that of Primrose and Prof. Smart in regard to the effect of quenching on the properties of gun-metal bronze. The writer's results have been published, so that there is no need for a detailed report, here, but his in-vestigations resulted in showing that both gun metal and manganese bronze are ruined by quenching in water from a red heat, apparently because they cannot stand the strains produced by the sudden cooling. The lines, mentioned by Prof. Smart, in a polished and etched section of the quenched metal have also been noticed by the writer, who however has not found them any different in quenched specimens than in annealed specimens. Since they appear only after etching, it would seem most probable that they are merely grain boundaries in most cases, though Prof. Smart's idea that they are indications of strains is by no means impossible. Fig. 1 shows how these lines appeared on the author's speci-mens of annealed gun metal, etched with ammonia and hydrogen per-oxide, and magnified 100 diameters.

Jan 11, 1919

By Benjamin C. B. Hsieh

Many processes in the hydrometallurgical and chemical industries require the separation of dissolved material from suspended solids. Counter current decantation (CCD) with thickeners is one of the methods generally used. The process engineer needs a quick and accurate CCD calculation method. Several theoretical 1-12 CCD calculation methods are available in the literature . The simultaneous 1, 2 equation method for a complex circuit as used would take too long to solve the problems. Approximate equation method1 is not accurate and is for simple cases only. A shortcut method developed by Counselman3 contains no mathematical equation, and thus is not suitable for computer programming. Based on Counselman's method, Woody4 derived two simple equations in terms of percent soluble loss for two typical examples. Scandrett5 included a term for mixing in his formulas. This mixing efficiency was defined by Murphree6. Another method which depends on making volume calculations instead of using weights is presented by Mastin8 and Cahalan9. None of these methods is related to dissolution and pre¬cipitation reactions. Chen 10,11 demonstrated his methods for counter current leaching. His results are calculated from the general solution of a derived linear difference equation for constant underflow, and from the solution of a derived non-linear Ricatti difference equation for variable underflow. This paper concerns derivation of a general equation for CCD washing with provisions for adding and withdrawing the streams, and for leaching (dissolution) or precipitation reactions. These equations take several forms depending on the input information available. A set of simplified equations for continuous counter current washing and leaching is derived for determining:

Jan 1, 1972

By R. O. Harma

Introduction Wet autogenous grinding is utilized in three iron ore concentrating plants operated by the Cleveland-Cliffs Iron Company (CCI). This paper will trace some of the development in converting from the use of metal grinding mill liners to the use of rubber and will update the current performance of rubber liners in these applications. The Cleveland-Cliffs Iron Company is a natural resources firm with major interests in iron ore mining and processing and oil and gas contract drilling. The company also has interests in oil shale, uranium, forest products, and Great Lakes shipping. The three operations discussed in this paper are the Empire and Tilden Mines on the Marquette Iron Range in Michigan's Upper Peninsula and the Sherman Mine in northern Ontario, Canada. The Empire Iron Mining Partnership is managed by The Cleveland-Cliffs Iron Company and is owned by Inland Steel, McLouth Steel, The Cleveland-Cliffs Iron Company, and International Harvester. The Tilden Iron Mining Partnership is also managed by The Cleveland-Cliffs Iron Company and is owned by Algoma Steel Corporation, Ltd., Jones & Laughlin Steel Corporation, The Cleveland-Cliffs Iron Company, Steel Company of Canada, Wheeling-Pittsburgh, and Sharon Steel Corporation. The Sherman Mine is a joint venture managed by Cliffs of Canada, Ltd. and owned by Dominion Foundries and Steel Company, Ltd. and Tetapaga Mining Company, a wholly owned subsidiary of The Cleveland-Cliffs Iron Company. The concentrators at all three mines utilize two stage autogenous grinding. Empire and Sherman process magnetic iron ores (Table 1) and utilize magnetic, hydraulic, and flotation concentration methods. Tilden processes an oxidized iron ore (martite, goethite, and hematite) and utilizes a selective-flocculation desliming and flotation concentration flowsheet. Final grind particle sizes are 90% -325M (43k) at Sherman, 90% -500M (25,u ) at Empire and 85% -500M (25 µ) at Tilden. Developmental History The success of using rubber mill linings in Scandinavia led to the first rubber mill lining used by CCI. It was installed in a conventional primary ball mill at Republic Mine in 1964 as reported by Lindroos (1970). This was followed by additional rubber liners for both primary and regrind ball mills. Generally these rubber linings provided about twice the service life as compared to the Type I Ni-hard liners previously used. Grinding efficiency of rubber was found to

Jan 1, 1982

By Hernán Arévalo

El presente texto describe las perspectivas en la utilización de la tecnología de conversión del carbón en los países latinoamericanos para producir petróleo sintético y derivados. En ese sentido, el proceso de gasificación carbón y síntesis en combustibles líquidos es costoso. Por ello, se requiere un análisis económico cuidadoso antes de decidir la instalación de cada planta en los países en América Latina y en el que los institutos geológicos y del carbón de los países de Latinoamerica inicien o continuen, según sea el caso, con la exploración de los recursos carboníferos para determinar reservas, incluyendo las de los carbones hidrocarburables.

Mar 1, 1982

By Richard W. Hutchinson, Christopher Osterman

Abstract -The Selebi-Phikwe deposits are hosted by amphibolite to granulite facies gneisses of the Limpopo belt. The sulfide orebodies are generally stratiform and conformable to the foliation of the wallrock gneiss. Sulfide remobilization has occurred during metamorphism and has produced discordant sulfide veins, called piercement structures, which project into the hanging wall and foot­ wall gneisses. These piercement structures are compositionally similar to the stratiform sulfides, consisting mainly of pyrrhotite, pentlandite and chalcopyrite. However, texturally the piercement sulfides are coarse grained and inclusion-free, whereas the stratiform sulfides are fine grained and packed with tectonically produced wallrock inclusions. The piercement structure sulfides and adjacent stratabound sulfides were sampled and analyzed for major base metals and PGE's for comparative purposes. Most of the piercement structures were enriched in Cu, Ag and Au, whereas they were generally depleted in Ni, Co, Fe and PGE's. Changing elemental associations were observed from the stratabound sulfides and along the length of the piercement structures. This and the degree of depletion or enrichment of various major and minor elements in the sulfide piercement structures may reflect the relative mobilities of metals under metamorphic conditions. The similarities between sulfide piercement structures and the footwall Cu-POE veins in some Sudbury deposits are reviewed.

Jan 1, 1994

By Roland W. Rammler

In recent years, the crude oil reserves of the world have increased at the same rate as the consumption. A Consideration of the global figures suggests that adequate supplies of petroleum will be available during the next decades. On the other hand, it in a fast of economic and political significance that the reserves in the industrialized countries increase much more slowly than in the developing countries. In Western Europe the reserves have even decreased. At the present time, about 70 % of the petroleum reserves of the world are in the Middle East and in Africa in regions in which political arises are prevalent or impending. For the industrialized countries, the discrepancies between the consumption and reserves in various regions of the world are a strong urge to investigate whether oil can be recovered from other sources. The situation will probably not be changed to a large extent by the discovery of oil in the north of Alaska. The main starting materials for the production of synthetic crude oil are coal, oil shale and tar sand. In North America, where the consumption of petroleum increases more rapidly than the reserves, there are enormous deposits of each of the three materials. This fact is another incentive toward the utilization of these unconventional oil reserves, which provide a reliable basis for a supple of energy for a long time to come.

Jan 1, 1970

By Harrison A. Schmitt

One of the great copper-producing areas of the world is comprised of five U. S. western states and northern Sonora, Mexico. The Southwest province of this area, covering southern Arizona, south- western New Mexico, and northern Sonora, produces some 55 pct of U. S. copper output and the equivalent of 15 pct of world production. In 1956 the area produced about 550,000 tons. Tucson is approximately the center of the oval- shaped province, which measures only 300 miles on its east-west axis and about 200 miles on its short axis. Northwest of the oval, and forming a tenuous connection with the Utah and Nevada copper fields, is an important operating mine, Bagdad, and also the now inactive United Verde. Along its north- south axis, running from Globe, through Tucson, to Nogales, ten moderate to major copper properties have been discovered or revived during the past 15 years, and five of these in only the past seven years. The latter five properties lie in an area 25 miles in diameter, centering 20 miles south of Tucson. In order of discovery, or revival, they are: Banner's Mineral Hill and Daisy; Cyprus et al's Pima; Duval's Esperanza; Asarco's East Pima (now called Mission mine) ; and Lewisohn's Peach. Total tonnage is estimated at about 250 million tons averaging some 0.90 pct Cu, but ultimate production may exceed this amount since some of the reserve is open ended.

Jan 6, 1959

By K. K. Bhattacharyya

In the Gulf Coast area lignite deposits occur in Texas, Louisiana, Arkansas, Mississippi and Alabama. Lignite has been mined in Texas since the early 1800's reaching a production of over 900,000 metric tons (1 million short tons) in 1910. With the availability of inexpensive oil and gas, production fall to as low as 16,000 metric tons (18,000 short tons) by 1950 (Henry, 1976). With the advent of the oil and gas shortage in early 1970, lignite production began to increase again. The purpose of this paper is to discuss the geotechnical considerations of mining lignite in the Gulf Coast area, particularly Texas and Louisiana. Lignite deposition occurs in unconsolidated sand, silt and clay environments. Extensive sand units saturated with water may be present within the potential mining depths. This paper describes the geotechnical considerations for designing a surface mine in this geographical area. These factors include geology, hydrology, mining method, and equipment utilization.

Jan 1, 1982

By Hugo Candiotti

El presente texto describe la secuencia de los trabajos de exploración realizados en el yacimiento de Sipán desde el descubrimiento hasta la puesta en producción. Así también, señala las características geológicas, mineralógicas y geoquímicas del yacimiento que contribuyeron a la localización y formación del cuerpo mineralizado de oro.

Apr 26, 1999

By William E. Ford, Edward Salisbury Dana

447. Minerals, as regards their chemical constitution, are either the uncombined elements in %native state, or definite compounds of these elements formed in accordance with chemical laws. It is the object of Chemical Mineralogy to determine the chemical composition of each species; to show the chemical relations of different species to each other where such exist; and also to explain the methods of distinguishing different minerals by chemical means. It thus embraces the most important part of Determinative Mineralogy. In order to understand the chemical constitution of minerals, some knowledge of the fundamental principles of Chemical Philosophy is required; and these are here briefly recapitulated. 448. Chemical Elements. - Chemistry recognizes about eighty sub- stances which cannot at will be decomposed, or divided into others, by any process of analysis at present known; these substances are called the chemical elements. A list of them is given in a later article (452) ; common examples are: Oxygen, nitrogen, hydrogen, chlorine, gold, silver, sodium, etc.

Jan 1, 1922

Jan 1, 1890

By Anthony McDonald, Dominic Verhelst

"Hudson Bay Mining and Smelting Co. Ltd. (HBM&S) started up a zinc plant and smelter in late 1930, employing technology of that period. The zinc plant has since converted from a roast/leach operation to a two stage pressure leach operation to eliminate sulphur dioxide emissioms. The smelter, however, is still continuing with much of the original roaster/reverberatory furnace technology. This paper reviews the process flow of the copper smelter, with some comments on past and recent changes.Smelter FlowsheetPrior to July 1993, the HBM&S smelter operation consisted of seven areas, namely feed preparation, roasters, reverberatory furnace, converters, anode casting, fuming plant, and dust collection. A simplified smelter flowsheet is shown in Figure 1. The data for tonnage of materials moving through the circuit are presented in Tables I to 4, and are representative of the time period from July 1992 to June 1993. A change in the zinc plant technology in 1993 resulted in the elimination of a zinc-bearing sulphide leach residue from the smelter feed blend, thereby greatly reducing the zinc content of slag produced in the smelter. Consequently the fuming plant and ancillary equipment, such as the drying plant, were shut down. These areas will, however, be described. With the closure of the zinc fuming furnaces all the slag from the reverberatory furnace is now discarded to stockpile.The over-all smelter metal recoveries are 96% for Cu and rn.5010 for Au and Ag. Figures 2 and 4 indicate historical production numbers of copper, silver and gold, respectively. A review of the minor element distribution in the smelter can be found elsewhere."

Jan 1, 1994

By Alfred H. Bell, Charles W. Carter

In 1942, Illinois produced 106,590,000 bbl. of crude oil, or 7.6 per cent of the entire amount produced in the United States. It ranked fifth among the oil- producing states. The production for 1942 declined 20.5 per cent from the previous year's total of 134,139,000 bbl. Tie daily average production for 1942 was approximately 292,000 bbl., or 74,000 bbl; less than the 366,000 daily average for 1941. At the beginning of 1942 the daily production was 367,000 bbl. This production declined steadily to 282,000 for June and to 246,000 for December. This steady decline was caused partly by the reduction in drilling resulting from Federal Conservation Order M-68 and partly by the fact that no major pool was found during the year. Discoveries Forty new fields (Fig. 2, Table 2), 48 extensions (Table 3), and 45 additional producing zones in existing fields (Table 4) Were discovered in 23 counties in Illinois during 1942. Of the 40 new fields, three

Jan 1, 1943

Trial ore production began at the Hilton Mine in 1987 with ore being trucked into Mount Isa for treatment at the Lead/zinc Concentrator. The expansion of output from the Hilton mine required additional concentrator capacity which led to the design and construction of the Hilton Concentrator. Systematic laboratory and Pilot Plant testwork dating back to 1968 to develop a flowsheet and reagent regime suited to the varied and generally complex mineralogy of the Hilton ore was successfully concluded with a Pilot Plant trial using a sulphoxy based sphalerite depression system in early 1988.In May 1988, a decision was made to build a 750 000 t/y concentrator with some novel technological and capital-efficient features. The Hilton Concentrator commenced operations in December 1989 reaching target grinding rates and metallurgical performance by mid-1990. Current ore treatment rate is 800 000 t/y.Lead concentrates assaying 43 - 48 per cent Pb are combined with the Lead/Zinc Concentrator lead concentrates and smelted at Mount Isa. Zinc and Low Grade Middlings (LGM) concentrates are filtered in the zinc filter plant at Isa with those from the Lead/Zinc Concentrator and then railed to Townsville for export or treatment in Australia.

Jan 1, 1993

By A. Acar, E. T. Tuzcu, Y. O. Vural

"In order to sustain the operations in chromite processing plants, due to concentrate selling cost, plants are in need of optimization in terms of capacity and recovery increase. In this study, DAMA Engineering carried out a methodological study for the purpose after a detailed sampling campaign in a plant which is situated in one the main chromite zones in Turkey; 1 The current status of the plant was investigated quantitatively with the bottlenecks, Plant overall efficiency in terms of recovery, Efficiencies of the particular equipment (mill, screen, gravity circuit), 2 A new circuit was proposed with the available equipment, 3 The new circuit that is product of modeling and experimental effort, was evaluated quantitatively as if it is a running plant, After 4-5 months continuous effort, the capacity of the plant was almost doubled (37 tph to 70 tph) and the plant overall recovery was increased from 48% to 63% by grinding adjustments and additional shaking tables theoretically. It was shown that the plant may move into profit with the minimum amount investment using readily available system. INTRODUCTION TO THE CURRENT PLANT The objective of the study is to increase the capacity and recovery of the chromite plant owned by Kurmel Group, Akmetal Inc. The complete study is given elsewhere (DAMA, 2016). The plant is situated in one of the main chromite zones in Turkey; Aladag. The current capacity of the plant is around 35 tph and the overall recovery declared by plant engineer is around 47 %. The chromite plant mainly has 3 units; crushing, grinding and gravitational circuits. The crushing circuit has 3 stages; a jaw crusher, a secondary cone crusher and a tertiary cone crusher operating in closed circuit with a vibrating screen with the aperture size of 15mm. In grinding circuit, a rod mill (2.44 6m x 3.6) and a ball mill (2.13 x 2.3m) are used for primary and secondary grinding, respectively. Derrick screens are used for the size separation. Additionally, for the size classification of the system, hydrosizers are used and each size fraction is sent to the shaking table sets. The middling product of the tables is subjected to re-grinding with a ball mill with the dimensions of 2.1 x 2.9 m. The capacity and the recovery are affected by several bottle necks; hydrosizers’ pure classification, primary/secondary mill power vs capacity problems, re-grinding product’s high slime content and so on. These combined factors made the plant to run in low recovery and capacity. Hence, DAMA was asked to make a study to investigate current status of the plant and propose a new solution to increase capacity and recovery of the plant. The conceptual flowsheet of the circuit is given in Figure 1 below."

Jan 1, 2017