Search Documents

By J. D. Forrester

Many have been prone to credit the decline of professional interest in some branches of mineral industry education to the industrialists and other agencies who use our graduates. We hear the cry that industrial salaries are too low, opportunities for advancement do not exist, and the mineral industry specifically and generally is not interested in the engineer's efforts. Perhaps the time now has come when we should "dress-ranks," examine our practices, and publicize and encourage advanced technical training instead of laying all our troubles elsewhere. There can be no doubt but that industry is interested and stands ready and willing to co-operate. This is demonstrated by the numerous grants-in-aid and co-operative industrial projects which have been made available to those relatively few schools which have been encouraging graduate study and research. There is no dearth of research problems in any of the mineral industry fields and the sooner we realize the great opportunities for constructive, technical research in all areas of our profession the sooner we will reap the benefits of our engineering enterprises by closer liaison and broader understanding with industry. An analysis is offered here of the status of graduate work and research in various phases of mineral industry education in the United States. It is

Jan 1, 1949

Jan 1, 1941

By Edward D. Thimons, Richard J. Kline

Converting the energy of falling water into useful work is a well developed engineering concept. Much of the electric power consumed in the United States is generated in this manner. It is easy to conceive that the water which flows down long vertical pipelines into deep nines could be utilized in a similar manner by allowing it to operate a turbine at the bottom of the pipelines. The mines in the United States are continually descending to greater depths in search of mineable deposits. Large quantities of water are carried down long vertical pipelines in order to be used for dust suppression, motor cooling, and refrigeration. Pumping the used water back to the surface is also required. The electrical costs associated with mining are also constantly escalating due to both increased demand and rising kilowatt hour costs. To help deal with this problem, the United States Bureau of Mines (USBM) has awarded a contract to Foster-Miller, Inc. of Waltham, MA, to investigate, evaluate, and demonstrate commercially available means of energy recovery for the deep mining industry. In other words, it demonstrates an efficient system for converting the energy of water flowing down vertical pipelines into useful mechanical or electrical energy.

Jan 1, 1982

By A. F. Meger

REPRESENTED here are the ideas and varied experiences of many people in the Hanna Coal Co. who have helped develop, over a number of years, an efficient and flexible method for spraying con- trolled amounts of oil on coal. Since the George- town preparation plant began operations early in 1951, oil treatment of coal has received special attention. It is believed that oil treating will satisfy present customers and also attract new markets. The first step in developing the new method of oil spraying was the construction of a dust cabinet for testing 50-lb samples of treated coal with the available oil sprays on the market. Tests results were tabulated for both indoor and outdoor storage.

Jan 7, 1954

By S. A. Braley

DRAINAGE water from coal mines is probably the most serious water pollution problem today, varying in importance according to location of the mines and geological structure. Drainage may be either acid or alkaline in character. Acid discharge, the most severely detrimental to a stream, is caused by natural oxidation of the sulfuritic material (FeS2) in the strata associated with the coal seam. Since the acid is the result of a natural reaction the acid water differs because it does not cease with abandonment of the mining operations. There is no known economical method of neutralizing acid mine water or any practical method to prevent oxidation of exposed pyrite. Since production of acid from a mine does not stop when mining stops, the total quantity produced depends entirely upon the excavated areas. The increasing volume of acid water in manv mines has greatly increased operating costs. Pumping is expensive and acid mine waters are destructive of all equipment, especially metals in pumps and piping, and necessitate the use of corrosion-resistant materials. Discharge of the acid mine drainage into streams neutralizes their normal alkalinity, causes them to become acid, and produces an environment unfavorable for aquatic life and unsuited for industrial or domestic use without costly treatment. Mine drainages vary in percentage composition over wide limits, although the usual dissolved substances are ferrous and ferric iron, aluminum, calcium and magnesium sulfates, and lesser amounts of sodium, potassium and manganese sulfates and chlorides. Some alkaline discharges may contain heavy concentrations of iron as iron bicarbonate. These waters may produce iron hydroxide deposits in the receiving stream but do not cause it to become acid. In the extensive literature on acid mine water there appears to be a great deal of confusion about the importance of various components and the methods for their determination. In many instances faulty conclusions have been drawn from use of unsuitable methods of analysis. It is desirable that the factors and terms used in evaluation of analyses of mine waters should be so clearly defined that any interested person could properly appraise any analytical report. Some analysts report complete chemical analyses of mine waters and neglect to record drainage volumes. Others report only a minimum of analytical data after taking no precautions to preserve the original composition of the water during the time elapsing between collection and analysis. Some use methods of analysis intended for so-called pure waters of the potable and boiler water classes. These methods are not applicable to highly buffered waters such as mine water. Probably the most common criteria for evaluation are pH, free acidity, or acidity or alkalinity to methyl orange or methyl red, total acidity or acidity to hot phenol-phthalein, and the sulfate content. If these determinations are made on carelessly collected samples after a few days to weeks standing in warm rooms, they do not in any way represent the character of the water flowing from the mines. It is hoped that a brief discussion of the fundamental value of some of these factors may lead to a bettqr understanding of the need for more careful evaluation of mine water discharges. The term pH is one used by chemists to express relative acidity or alkalinity in terms of concentration of effective hydrogen ion in a solution. It is defined as the negative logarithm of the hydrogen ion concentration or activity in equivalents per liter. pH = logarithm A neutral solution, which is one containing the same number of hydrogen and hydroxyl ions, has a pH of 7. As the hydrogen ions increase and the solution becomes more acid, the pH decreases toward zero; and as the hydroxyl ions increase and the solution becomes more alkaline, the pH approaches 14. When dissolved in water to a dilute solution acids like sulfuric and hydrochloric, commonly known as strong acids, ionize completely, and the pH or hydrogen ion concentration varies with molar concentration of the dissolved acid. However, in high concentrations of such acids, the pH or hydrogen ion concentration is less than the acid concentration because the acid does not completely ionize. In only very dilute solutions does the pH represent the total amount of acid that can be neutralized by an alkali. All ionization reactions are equilibrium reactions. If other chemicals are added to the solution of an acid and the added chemical produces an ion that is the same as one of the ions of the acid, the degree of ionization of the acid is altered and the pH changes to some value that represents the active hydrogen ion of the new solution. Thus if iron sulfate is added to a solution of sulfuric acid the pH increases, since the common sulfate ion suppresses the degree of ionization of the sulfuric acid and decreases the effective hydrogen ion. However, the total acidity of the solution is increased. There are two salts composed of iron and sulfate— ferrous and ferric sulfate. In these salts there is no hydrogen ion that can ionize to give an acid solution, but when they are dissolved in water, the pH is less than 7 and the solution becomes acid. This is caused by a reaction known as hydrolysis and is represented by the equations FeSO4 + 2H2O ? Fe(OH)2 + 2H + SO,: or Fe,(SO,)3 + 6H2O ? 2Fe(OH)3 + 6H+ + 3504 A solution with a total acidity of 5000 ppm according to the first equation will have a pH of 4.40 but one with an acidity of 75 ppm, according to the sec-

Jan 1, 1958

By Frank T. Wheby

The cost of tunneling is highly sensitive to the rock characteristics through which the tunnel is to be driven. These characteristics affect in a major way the rates at which tunnels and shafts can be driven and the degree to which the openings must be supported to maintain them in a permanent stable condition. Tunnel and shaft design and cost criteria have been computerized, permitting estimates of tunnel-shaft systems to be made directly from inputs of rock mechanics characteristics and other data. Curves of quantities of steel, rock bolts, and other rock support items as related to tunnel size and rock quality designation are presented. An illustrative example of the use of the program in calculating the cost of a hypothetical tunnel system is included.

Jan 1, 1971

US Tin Mission To Study Costs in Far East A move to obtain adequate supplies of tin at prices the United States is willing to pay was initiated when the interagency tin mission left for the Far East. The Mission, which includes representatives of the Reconstruction Finance Corporation, State Department, Defense Minerals Procurement Agency and the Bureau of Mines will go to Indonesia and Malaya. The primary purpose of the mission, according to officials, will be to study tin production costs, not to negotiate for the purchase of tin. The mission will be prepared to enter into negotiations, if the Far Eastern producers are amenable. The United States withdrew as a large-scale buyer of tin some months ago in protest against what it considered exorbitant prices being charged in the Singapore market. Subsequent attempts to negotiate for a steady tin supply at what this country considers reasonable prices have been unavailing. The U. S. is prepared to enter into a two or three year contract with the price of tin somewhere between $1.00 to $1.12 per lb. The decision to abstain from the market has not yet put a squeeze on U. S. supplies. Substantial quantities of tin still are coming in from Malaya under an old contract.

Jan 12, 1951

W. H. SHOCKLEY, Chairman, FRANK H.-PROBERT, :Vice-Chairman, T. A. RICKARD, Sec.-Treas.; 420 Market St.,. San Francisco, Cal. C. C. BRAYTON, J. F. NEWSOM. A Meeting of the San Francisco Section was held on May 7, 1917. Chairman Shockley was in the Chair. The Section was honored by the presence of President Moore and Secretary Stoughton of the Institute. C. W. Merrill introduced President Moore, who then spoke to the Section on the Aims of the Institute. He discussed the possibility of improving the standards of membership by introducing a classification of membership. The present rigid investigation of applicants was pointed out by him. He spoke of the important influence that the local Sections can exert on the Institute and of the importance of sociability and informality at the meetings. Secretary Stoughton, who was introduced by the Chairman, emphasized somewhat the same points. He mentioned the need for making the Bulletin of the Institute more, interesting than it is at present, this to be accomplished by raising the necessary funds by increased advertising. He asked for an expression of opinion on this point. He. said that the employment department of the Institute is now used extensively. At the request of Mrs. Mark L. Requa, Mr. Stoughton. announced that a San Francisco branch of the Woman's Auxiliary of the, Institute was being formed and asked that the ladies of the members' families send in their names to Mrs. Requa or to the Secretary of the Institute.

Jan 10, 1917

By L. A. Roe

The flotation of fine particles less than five microns in diameter and the flotation of liquids from liquids generally requires bubble generation methods different than methods used in dispersed air type machines used in mineral flotation. Conditions in the separatory zone in mineral cells are generally more dynamic as compared to the quiescent conditions often absolutely necessary for the flotation of fine particles and liquids. An example of quiescent flotation with very fine bubbles is the lithium flotation plant which operated at Trona, California for 34 years, until it ceased operations in 1978. A review of the process development and the commercial flotation operations at Trona is given in this paper. The clarification of oil field brines by flotation of the oil from the brine has been used for over twenty-five years. Recent installations related to the Prudhoe Bay oil field and the Alaska pipeline are described.

Jan 1, 1980

Welfare endeavor in connection with both the metal and the coal mines of Utah has shown gratifying progress during recent years and both the operators and their employees are deserving of much credit for the efforts put forth to better living, working, educational and receational conditions in most of the mining camps of the state. In the older metal mining camps of Utah, where the towns are incorporated and independent of the mining properties operating in the vicinity, less opportunity is presented for the companies to exercise efforts looking towards improved welfare conditions than is the case of camps located on company ground and under the full control of operators.

Jan 1, 1925

By George J. Simchuk

Selection of an applicable stripping method and the subsequent determination of appropriate sizes of selected equipment are discussed. The case in point is Utah International, Inc.'s Goonyella mine located in central Queensland, Australia. A detailed study of the various types of stripping methods now practiced throughout the world led to the conclusion that large draglines would be the logical choice for Goonyella. The optimal size of dragline was then determined by first designing a series of cut diagrams using an array of machine and pit geometries followed by a cost comparison of the various sizes of machines, in terms of their effective spoil radius. A dragline with a 51-cu-yd bucket was determined to be of optimum size. Further calculations, incorporating total overburden moved from both the highwall and spoil sides, required that four drag lines, two equipped with 40-cy-yd buckets and two with 54-cu-yd buckets, be used to satisfy the stripping requirements at Goonyella.

Jan 1, 1973

By Om P. Garg

During the period between 1970 and 1974 the Iron Ore Company of Canada had embarked on a detailed program to evaluate all aspects of mine design work for its open pit mines around Schefferville, located both in Quebec and Labrador, Newfoundland, Canada. One of the main conclusions was that the majority of the slope angles for the ultimate pit walls could be steeped. During the period 1975 and 1976,five (5) open pit iron ore mines were redesigned using the steeper slope angles up to 55 degrees. Initially these pits were designed at slope angles varying between 37 degrees and 45 degrees due to the generally fractured and leached nature of rocks in the area. During the active mining phase between 1976 and 1979, the stability of the steeper ultimate pit walls was monitored. The mining of ore was successfully completed in 1978 and 1979 in three pits. This of course, resulted in a significant savings due to a reduction in the quantity of waste that had to be removed. The successful pit slope redesign project was a co-operative effort between the Federal Government, Universities and the Iron Ore Company of Canada.

Jan 1, 1983

By R. H. B. Jones

This paper reviews pertinent geology of the Biwabik iron formation, Mesabi Range, Minnesota. This iron formation is divisible into four members. Each member is distinctive and contains marker horizons, which are recog nizable throughout all phases of alteration from lean, fresh rock to high-grade iron ore. Some beds have a larger magnetite content than others. During the process of ore genesis, which is essentially an oxidation process, the magnetite content is lowered. Alteration from iron formation to ore includes both oxidation of iron minerals and silica removal by leaching and these distinct processes progress at variable rates for different locations and structures. Magnetic intensities, of each horizon of the iron formation are dependent chiefly upon its preoxidation magnetite content, upon the subsequent degree of oxidation, upon the character of the enclosing rocks, and on the extent of fracturing, folding, or faulting. The results of a number of magnetic surveys are described and are correlated with results of drill-hole and mine exploration and developmerit. The magnetic anomalies obtained are discussed in relation to phases of formation of ore within the iron formation. General Information One hundred years ago a party of surveyors, applying the principles of geophysical prospecting, discovered iron ore in the state of Michigan in the Lake Superior district. This event was officially reported as follows:' On Sept. 19 (1844) while running the east line of Town 47 North, Range 27 West, they observed by means of the solar compass remarkable variations in the direction of the needle, amounting to 87" from the normal. Ascribing this phenomenon to iron ore, they sought and found it in ledges or outcrops at several points. The solar compass referred to was invented by William A. Burt, deputy surveyor in charge of this party.2 It is used for determining the true meridian by an observation on the sun. Eight years later, on July 7, 1852, the first iron 're, consisting of 6 bbl. of Ore, was shipped from Marquette, Michigan. It was another 40 years before the first or> shipment left the Mesabi Range in Minnesota, in October 1892. It totaled 4245 tons. Fifty years later, 90 years after the original shipment, during 1942 the Lake Superior district shipped 93,495,392 gross tons of iron ore. Production came from Minnesota, Michigan, Wisconsin, and Ontario, Canada. Throughout the 90-Year period it was known that magnetic properties of most of the ore bodies, and of the iron formations in which they occur, affected the compass. This phenomenon, later to be made use of to outline areas of ground favorable for exploration, was at first a

Jan 1, 1949

By R. H. B. Jones

This paper reviews pertinent geology of the Biwabik iron formation, Mesabi Range, Minnesota. This iron formation is divisible into four members. Each member is distinctive and contains marker horizons, which are recog nizable throughout all phases of alteration from lean, fresh rock to high-grade iron ore. Some beds have a larger magnetite content than others. During the process of ore genesis, which is essentially an oxidation process, the magnetite content is lowered. Alteration from iron formation to ore includes both oxidation of iron minerals and silica removal by leaching and these distinct processes progress at variable rates for different locations and structures. Magnetic intensities, of each horizon of the iron formation are dependent chiefly upon its preoxidation magnetite content, upon the subsequent degree of oxidation, upon the character of the enclosing rocks, and on the extent of fracturing, folding, or faulting. The results of a number of magnetic surveys are described and are correlated with results of drill-hole and mine exploration and developmerit. The magnetic anomalies obtained are discussed in relation to phases of formation of ore within the iron formation. General Information One hundred years ago a party of surveyors, applying the principles of geophysical prospecting, discovered iron ore in the state of Michigan in the Lake Superior district. This event was officially reported as follows:' On Sept. 19 (1844) while running the east line of Town 47 North, Range 27 West, they observed by means of the solar compass remarkable variations in the direction of the needle, amounting to 87" from the normal. Ascribing this phenomenon to iron ore, they sought and found it in ledges or outcrops at several points. The solar compass referred to was invented by William A. Burt, deputy surveyor in charge of this party.2 It is used for determining the true meridian by an observation on the sun. Eight years later, on July 7, 1852, the first iron 're, consisting of 6 bbl. of Ore, was shipped from Marquette, Michigan. It was another 40 years before the first or> shipment left the Mesabi Range in Minnesota, in October 1892. It totaled 4245 tons. Fifty years later, 90 years after the original shipment, during 1942 the Lake Superior district shipped 93,495,392 gross tons of iron ore. Production came from Minnesota, Michigan, Wisconsin, and Ontario, Canada. Throughout the 90-Year period it was known that magnetic properties of most of the ore bodies, and of the iron formations in which they occur, affected the compass. This phenomenon, later to be made use of to outline areas of ground favorable for exploration, was at first a

Jan 1, 1949

By R. M. Daelen

Mechanical science is severely tested by the demands of the iron manufacture for the varied apparatus needed to transport and to treat raw materials and products. Water has long been a favorite means of transmitting pressure for such purposes, because of its own incompressibility. Further advances in its use are the more to be expected, since mechanical improvements have steadily tended to overcome the difficulties formerly encountered in the employment of great hydraulic pressures. So long as the pressure is not higher than that which requires for plungers, etc., only ordinary stuffing-boxes, with hemp or other similar packing, the necessary arrangements for the production and transmission of the water-pressure without leakage are very simple. But when this limit (which is, for most purposes, 50 kilos to the square centimeter) is exceeded, new conditions of construction arise, which are met in various ways, and which justify a primary division of hydraulic presses into low-pressure and high-pressure respectively. The former are used in lifting and moving weights, and employ pressures as high (in extreme cases) as 100 kilos per square centimeter; but at this point the friction between piston and hemp-packing is so great that the use of cup-leathers is already preferable. Beyond 100 kilos it becomes a necessity. The range of practicable tight packing which follows is considerable, extending to about 1000 kilos; but "high pressure" in practice is from 100 to 600 kilos, and it is to this that the present paper applies. General Classes and Types. Hydraulic transmission at high pressure usually claims consideration in case the solid mechanism, such as levers, cams, screws, and gear-wheels, would have to be too large, would involve too much friction, or could not be suitably adapted to the speed-requirements of the working-tools. Since steam is mostly the primary carrier of

Jan 1, 1893

By Michael P. Robinson

It has been suggested that streaming potentials are not nomlally logged because the streaming potentials known to be generated across mud filter cakes are substantially cancelled by streaming potentials generated in contiguous shale beds. Laboratory measuments of streaming poterztials acrons hand specirnens of shale have been adduced as evidence to support the suggestion. The experiments show that streanzing potential depends on the resistivity of the equilibrating solution and on pressure drop. Meizsurenlents were made perpendicular to the bedding planes of the shales. The mechanism of streaming potential generation in shale which the suggested cancellation theory iniplies has been critically examined. Conclusions reached are tested by comparing self potentials logged before and immediately after changing the resistil~ity (but not the weight) of mud in a borehole. The resultant SP change is found to equal the theoretical electrochetnical potential change, i.e., cancellation of .strearning potential is independent of mud resistivity. Since streaming po/entials generateal across mud filter cakes depend critically upon mud reistivity, shale .strearlling potential in situ must he equally sensitive. Using plausible values for the pemleahility, porosiy arzd compressibility of shale, the van Ererdingerl-Hurst approach shows that the pressure drop between horehole pressure and formation pressure in a radially honzogeneous shale is unlikely to coincide with the zone of filtrate invasion. If, perchance. this coincidence occurs with one mud a chatzge 10 a second must result in non-coincidence, i.e., a .YP logged in the second mud should show a streaming potenlial. The dilernrna may he overcome by postrrlating: (I) perrneabilities of shale7 parallel to their beddine planes greatly exceed their cross-bedding permeabilities; (2) a resistivity-sensitive mud cake of low permeability forms either on the face of, or probnhly in the lanlinations of, many shales. These postulates are examined with reference to the pres.sure and SP histories of the McClosky and Aux Vases zones in the Illinois Basin and some srcpport for them found. It is concluded that a definitive solultion to the streaming potential problem does not exist. INTRODUCTION Recently Gondouin and Scala' published a contribution to the streaming potential problem which is notable particularly for the elegance of its experimental techniques. The conclusions drawn by Gondouin and Scala from their studies amplified those previously suggested by Schehck'. In essence they suggested that the streaming potentials known to develop across mud filter cakes" are not normally observed on SP logs because they are largely cancelled by streaming potentials generated in adjacent shales. This suggestion appears so reasonable that many workers in the logging field will be prone to accept it. We incline strongly to the view that the suggestion is basically correct. Nevertheless, it is important to realize that the cancellation hypothesis in the form put forward by Gondouin and Scala does not appear to meet all the known experimental facts. It is the principal intention of this note to call attention to what appears to be a flaw in the relevancy of the experimental evidence adduced by Gondouin and Scala and to suggest an alternative hypothesis to remove it. The consequences of the new hypothesis are compared with field data which, we believe, are unique. A second but not less important purpose of this note is to emphasize that even the new hypothesis does not fully explain all field observations. Hence we conclude that further study of the streaming potential problem is required before it can be said that a definitive solution to it has been attained. The bare experimental bones of laboratory data on streaming potentials appear to be as follows. 1. A streaming potential is developed across a mud filter cake. This streaming potential is virtually independent of cake thickness but depends on the mud resistivity. The relationship is of the form, 2. A streaming potential is developed across a shale. This potential is independent of shale thickness but depends on the resistivity of the permeating solution if the shale has been first equilibrated in this solution. The relationship is of the form, The relationship in (1) was determined first by Wyllie3, confirmed by Gondouin and Scala and qualita-

By Kurt Kennedy

A method is described by which three elements can be condensed simirltaneously on a common substrate in such a way that the composition varies with position on the substrate. Almost all possible combinations of three solid elements can be formed in a single evaporation. The three elements are heated by magnetically deflected electron beams. The alloys and cornpounds formed by this method generally correspond to those trade by other methods; however, many exceptions exist. Simple symmetric crystallographic phases tend to form in preference to more complex phases. The Nb-Sn. Cr-Fe-Nt, and other systems of alloys made by this method will be discussed. Phases that form very slowly, such as the o phase in Cr-Fe alloys, may be formed rapidly by this method when certain substrate temperatures are used. STUDYING all the mixtures and compounds of two or more elements by the preparation of individual samples forces the investigator to make sampling sufficiently close together so that the properties of the intermediate compositions can be inferred. A completely unknown system will require a dis c our aging ly large number of preparations in order to fully know all its properties. For the purpose of expediting this type of investigation, methods have been devised to prepare samples that have a continuous variation in composition over some predefined area. The code-position of two elements onto suitable substrates has been used to produce alloys or compounds that have variable compositions depending on their positions on the substrates Composition gradients have been formed by depositing a wedge-shaped layer of one element and then depositing a second wedge-shaped layer on top of it such that the total film thickness is kept constant. Concentration equilibrium perpendicular to the surface is then established by annealing.4 This paper describes a method for the simultaneous condensation of three volatile components on a substrate such that there is a regular variation of composition with position on the substrate. The arrangement of the evaporation sources and the substrate is shown schematically in Fig. 1. Materials to be evaporated are placed in three water-cooled crucibles located at the corners of a 10-in. equilateral triangle. Electron beams from cathodes located below the crucibles are bent 180 deg by magnetic fields and focused on the material to be evaporated. The cathodes are connected in parallel to a constant-current 12-kv power supply. The distribution of emission current from each cathode is controlled by filament temperature. When materials that sublime are to be evaporated, the electron beam is deflected by an auxiliary ac magnetic field so that the beam moves over the surface of the evaporating material rather than digging a hole in one spot. The substrate is a 10-in. triangle of 2-mil stainless steel or molybdenum which is stretched against a slightly curved heat sink by a frame as shown in Fig. 2. This frame and heat sink are located so that each corner is directly above an evaporation source. The heat sink has three radiant heaters at each corner that can be separately controlled permitting the

Jan 1, 1967

By Alfred Weiss

Daniel C. Jackling's innovative concept for handling low grade ores ushered in a new philosophy of open pit mining. As one of the greatest minemakers of all times he revolutionized major segments of the industry and helped strengthen US defense efforts during World Wars I and II by making possible the tremendous copper supplies from US mines. Many great mining men have since followed in his footsteps with their discoveries of new orebodies or development of new mines. Their brilliance in leadership can also be traced to the coupling of a new idea to the physical nature of the materials in the earth's crust or to the extractive stages of minerals recovery. The minerals industry is now in another era of change and must again devise techniques to meet the challenge. The task is not only to create new exploration techniques and develop new mining methods, but, I believe, to optimally apply new concepts and tools in daily decision-making.

Jan 11, 1978

By R. B. Schluter, M. M. Fine

A process for winning copper from pelletized chalcocite concentrate without matte smelting and converting is under development at the Twin Cities Metallurgy Research Center of the U.S. Bureau of Mines. The new procedure includes a two-stage fluid-bed treatment in which the pelletized concentrate with 33% Cu and 7% S is first desulfurized to about 0.5% S in an oxidizing atmosphere, and then metallized by reduction with hydrogen. The reduced product is melted with flux to separate metallic copper from the gangue. The metal must be refined to remove residual sulfur and iron. The pelletizing of the fine concentrate into mini-pellets prior to fluid-bed treatment is an important feature of the process, because it permits shorter reaction time, decreases dusting, and facilitates subsequent processing.

Jan 1, 1972

By H. E. Wilborg

This chapter deals with those sands employed by the foundries for the manufacture of cores and molds used in the casting of such common metals as steel, gray iron, ductile iron, aluminum-based alloys, and copper-based alloys. Most metal is cast in "green sand" molds in which the sand mixture, consisting primarily of silica, clay, and water, forms a plastic material. This plastic material is rammed around a pattern in a split box called a flask, then the box is separated, the pattern is withdrawn, and the metal poured. These green sand molds are broken apart when the metal has solidified. The sand is then remixed and a new mold made for the next casting. To a lesser extent silica sand is mixed with resins or oils and, after forming, the mixture is hardened either by heat or chemical reaction. In any case, the foundry mold or core is used just once before being broken up and remixed for manufacturing another core or mold. By far the greatest consumption in the foundry is of those types of sand high in silica, low in clay (under 0.5%) and occurring in numerous locations thoughout the United States.

Jan 1, 1975