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By Edward Keller

Someone some time ago remarked that some chemists still insist on telling us how to determine copper by the electrolytic method. The writer must confess that he believes that everything is not known definitely as yet as to how the exact amount of copper is determined in such material as purest commercial electrolytic copper. Some of us are not yet convinced that the pure copper atom is at all times deposited from an acid solution and that no oxygen or hydrogen will, under certain conditions, accompany it. Difficulties with impurer material are frequent, but erroneous results are not always apparent, since these do not speak so readily for themselves as those in the first case. By this is meant that if a chemist finds 100 per cent. of copper in electrolytic copper it is pretty certain that he perceives the result to be wrong, while if he finds 0.1 per cent. of copper too much in a very impure material he is far more likely to be unconscious of his error. These, in a wide experience, are frequent happenings and the writer has always looked with interest to publications on this subject. In turn, he feels justified in giving to others a few of his own observations. Up to a few years ago there were two methods of electrolytic copper assay in technical use, which had in common, that the amount of copper deposited on the cathode did not exceed 2 g., and they differed in that, for the one a large sample1 (20 to 80 g.) was taken from the general sample by a splitting device, dissolved, and from the solution a small portion (to contain 1 or 2 g. of copper) measured out for the electrolytic deposition; in the other method the copper was determined, generally in 1-g. portions of the separated coarse and fine portions of the sample, all of which passed a 16 or 20-mesh screen, being accomplished by a 40-mesh screen,

Jan 1, 1914

By James W. Shaffer

Aluminum is the most abundant metallic element and forms 8% of the earth's crust. Because of its chemical activity it does not occur in nature in a metallic form but principally in the silicates, feldspar, mica, shale, and clay. Bauxitic raw materials-bauxitic clay, aluminous laterite, and bauxite-develop from these aluminum silicate sources. Bauxite and aluminous laterite are naturally occurring mixtures of aluminum hydroxides and mineral impurities, and they are the major sources of aluminum. End Uses Bauxite is the basic ore of the aluminum industry. It is refined into aluminum hydroxide and calcined for feed stock to electrolytic smelters. Over 90% of the tonnage mined is refined and smelted into aluminum. The total tonnage consumed by other industries is small in comparison, but bauxite and alumina are important for the manufacture of refractories, ceramics, chemicals, abrasives, pharmaceuticals, catalysts, cements, dessicants, and flame retardants. Some aluminum-containing industrial products are made from clays and other materials but the majority originate from bauxite directly or from aluminum hydroxide and alumina refined from bauxite. Lateritic type bauxite is also used as building and decorative stone. Geology Mineralogy and Properties Bauxite is a mineral raw material composed principally of one or more aluminum hydroxide minerals and impurities of silica, iron oxide, titania, and other elements in minor or trace amounts. The important aluminum hydroxide minerals are gibbsite, boehmite, and diaspore. Bayerite, nordstrandite, and tucanite are naturally occurring aluminum hydroxides but are rare and not commercially important. Mixtures of gibbsite and boehmite are common, boehmite and diaspore less common, and gibbsite and diaspore rare. Gibbsite is aluminum trihydroxide. Boehmite and diaspore are aluminum oxide hydroxides and have essentially the same composition, but diaspore has a greater hardness and a more tightly bonded and denser atomic structure. Although not technically correct, the commercial terms trihydrate and monohydrate are frequently used to distinguish types of bauxite. If bauxite is all or nearly all gibbsite, it is referred to as a trihydrate ore; if boehmite or diaspore or a mixture of both are the dominant minerals, the bauxite is called a monohydrate ore. If substantial amounts of both gibbsite and boehmite are present, the bauxite is frequently referred to as a mixed ore. Properties of major bauxite minerals are shown in Table 1. Silica, iron oxides, and titania are major impurities always present in deposits of bauxitic raw materials.. Silica impurities usually occur as clay minerals, micaceous minerals, or quartz, but cristobalite and feldspar are found in some deposits. The most common clay minerals are kaolins; however, illites and chlorites are often found in small quantities. Varying proportions of aluminum, iron, and clay minerals make bauxite, aluminous laterite, ferruginous laterite, and bauxitic clay deposits gradational with each other. Hematite and goethite are the common iron mineral impurities in many bauxites. Magnetite and ilmenite occur in deposits derived from basic igneous rocks. Other iron minerals associated with bauxite are maghemite, pyrite, siderite, and marcasite. The titanium minerals found in bauxites are anatase, leucoxene, rutile, ilmenite, titaniferous

Jan 1, 1983

By John C. Smock

The ten years, 1879 to 1888, inclusive, have been notable in the history of iron-making for the great rise during the latter part of 1879 and the earlier half of 1880; for the maximum of production in 1882 ; for the gradual decline and the reduced product through 1883,1884 and nearly to the end of 1885; then, for the recovery through- 1886 and 1887; and the extraordinary outputs of our iron furnaces during the last three years. The price of pig-iron might be taken as an index to the condition of the iron-mining industry, and if represented graphically, they would shorn approximately parallel curves. The mining industry cannot always respond quickly to a rise in price and an increased demand for ore; nor can its production drop simultaneously with sudden falls in price of iron and of ore. Hence, the irregularities of the one are not reflected in the other. The statistics of the iron mines collected by the United States census, for the year ending June 30, 1880, exhibit admirably their condition at that time. The reports received from mine owners and managers, of the production for the year 1888, furnish the basis for a comparison and supply data for some notes on the changes in the iron-mining industry in New York which have taken place in this period of time. The iron-ores of New York may be grouped in the following districts: I. The Highlands of the Hudson (magnetites). II. The Lake Champlain and Adirondack Region (magnetites). III. St. Lawrence and Jefferson Counties (red hematites). IV. Clinton and Wayne Counties (fossil-ores of the Clinton Group). V. Dutchess and Colnmbia Counties (limonites). VI. The Hudson River (carbonates). VII. Staten Island (limonites). The ores of the first and second districts, as enumerated, are almost exclusively magnetites; those of the third and fourth are hematites;

Jan 1, 1889

By Nelson Severinghaus

Crushed stone leads all industrial mineral, except cement in annual value of production in the United States. It is also interesting to note that crushed stone value is exceeded only by that of fuels, cement, and iron ore among all mineral products of this country. An industry which started with hand-sledging to produce smaller sizes of broken stone for hard surfaced improvement of roadways as designed by McAdam in England about 1815 has grown into a complex industrial giant. Most of this growth started with the invention of a mechanical rock crusher just under one hundred years age (1858) by Eli Whitney Blake. This invention made possible the production of greater tonnages of smaller sizes of broken stone and greatly accelerated its use for Macadam road pavements and for railroad ballast. Stones Used for Crushing All three of the major geologic classifications of stone, sedimentary, igneous, and metamorphic, are widely used in the production of crushed stone. Satisfactory physical and chemical properties can be found in each type so that economic availability becomes the prime determinant for development. Table 1 lists more common rocks of the three main groups with average values of specific gravity and toughness as measured by Deval test. This widely used classification was suggested by C. E. Lord, of U. S. Bureau of Public Roads. The physical properties were compiled by D. O. Woolf in "The Results of Physical Tests of Road Building Rock," U. S. Department of Agriculture, Bulletin 76. It should be noted that the figures given in Table 1 are averages. Very substantial variations in the physical properties of rocks within any one classification will occur. The solid surface of the earth was first made up of igneous rocks resulting from the solidification or crystallization of molten material upon cooling. These igneous rocks were disintegrated into sand, clay, and gravel by the weathering action of wind, water, chemicals, [ ] and temperature changes. The products of weathering were transported by wind and streams until they reached less turbulent areas such as oceans or lakes and were deposited. Chemical deposition between grains of sand or clay or the physical action of pressure and heat then solidified them into sedimentary rocks

Jan 1, 1960

By George I. Adams

A party, consisting of George I. Adams, of the United States Geological Survey, A. H. Purdue, of the University of Arkansas, and Ernest F. Burchard, was engaged, during the summer of 1902, in the study of the zinc- and lead-deposits of Northern Arkansas. An extensive report on this field is now in preparation. The following preliminary statement of results and conclusions is made in advance of the final publication, which will be accompanied by detailed geologic maps and other illustrations and a fuller treatment of the subject. Location.—The Northern Arkansas field embraces Marion county and adjacent portions of Boone, Baxter, Newton and Searcy counties. Outside of this area there are a few scat tered mines, notably in Sharp and Lawrence counties. The mining development lies north of the Boston mountains, in what is known as the Ozark Plateau. The country has a broken surface, as a result of dissection by streams, and there are numerous exposures of the mineral-bearing horizons in the valley slopes. This has greatly facilitated prospecting. History.—Lead-ore was discovered in Northern Arkansas by the early explorers and pioneers, and at first was utilized for rifle-ballets. Later, it attracted considerable attention, and in the '50's was smelted in the vicinity of Lead Hill. There was a revival of the industry during the "70's, but the cost of transportation was so great that it was practically abandoned. Zinc-ores at first attracted little attention, probably because they were not so well understood. Before the Civil War, however, some zinc was smelted. In the '80's, prospecting was carried on generally throughout the field, and resulted in finding zinc at so many places and so readily accessible that

Jan 1, 1904

By O. W. Ellis

RECENTLY there has been a considerable revival of interest in the effects of the various elements commonly added to brass for the purpose of increasing its strength. For many years the work of Guillet2? alone gave reliable information in this regard. Even today his determination's of the coefficients of equivalence of the various elements relative to zinc in brass are those universally employed in industry. This is so because these coefficients have stood the test of time-their substantial correctness has been proved in almost universal practice. It is not our intention to discuss here these coefficients or their use. Rather do we wish to emphasize the need for further systematic studies of the mechanical properties of the ternary systems of copper, zinc, and other individual elements. Since Guillet published the results of his first investigations Millington,16 Smalley33 and Thibaud45 have added somewhat to our information. In general they have confirmed the findings of Guillet, which may be stated in the following rather general terms: 1. The addition of aluminum to the 70:30 and 60:40 brasses progressively increases their hardness and strength and reduces their ductility and resistance to shock. 2. The addition of small amounts of iron to a 60:40 brass improves its strength without affecting its ductility. 3. The addition of small amounts of manganese to a 60:40 brass causes a progressive increase in its strength and reduction in its ductility. A considerable amount of information has been amassed in regard to the effect of nickel on brass (9, 22, 41) which it is unnecessary to refer to here, in view of the scope of this paper.

Jan 1, 1929

By H. O. Hofman

The substance of this paper was prepared for the Seventh International Congress of Applied Chemistry, held in London, May, 1909, under the title, Some Developments in Blast-Roasting. In the absence of the author, a short abstract of the paper was read, and the abstract only will appear in the proceedings of the congress. The present paper has been partly rewritten and considerably enlarged by information gained since the original was prepared; also some illustrations have been added. Blast-roasting* is a generic term for the process of forcing air through finely-divided metallic sulphide with the object of roasting and agglomerating in a single operation. At first the process was confined to a galena-concentrate; lime, limestone, or gypsum was added, to serve both as a diluent to keep separate the particles of galena that they might be thoroughly oxidized, and as a flux that the partly-roasted ore niight be agglomerated by the formation of some slag. Later it was extended to treat other metallic sulphides. The leading processes were the Huntington-Heberlein and the Savelsberg of Europe, and the Carmichael-Bradford of Australia. In the United States and Canada, the Huntington-Heberlein process has found application in some instances with galena-concentrates, for which it was originally intended; but this class of ore is not often treated alone, hence the process has had to be modified to suit conditions. The Savelsberg process has been transplanted to this country in about its original form. The Carmichael-Bradford is not used at present. The changes called for in the Huntington-Heberlein process to adapt it to the class of lead-bearing ores usually smelted have been the

Jan 1, 1911

By J. Blodget Britton

SIX different samples of anthracite, each a firm compact lump, were finely pulverized and immediately put in bottles. Portions of these were weighed and placed upon an ordinary water-bath and dried for one hour; the average loss was 1.24. The same portions were then placed in a hot-air oven, and for two hours kept at a temperature of 285' F., and, after cooling in a dry chamber, were again weighed, when there was found a further average loss of 1.22, making a total so far of 2.46. They were then immediately returned to the oven and for two hours more kept at a temperature of 530' F. and cooled and weighed again, when no further loss was found, but an average gain of .55 upon the previous weighing. The same portions were a third time placed in the oven and for about ten minutes kept at the last-mentioned temperature, and then, while still hot, were poured into one-quarter inch glass tubes, each with a bulb at one end, and heated over a Bunsen burner at a temperature below a red heat, when more water vaporized and condensed in small clear globules on the cold parts of the tubes. Fresh portions of the coals were then taken, and the total amount of water determined, and the average was found to be 3.04, or 1.80 more than was found at the temperature of the water-bath, which was perhaps a little below 212' F., and .58 more than at 285' F. Tests were afterwards made by placing other fresh portions of the

By C. H. G. Bushell, James E. Lawver, William Barbarowicz

Proper use of automatic controls in the process industries is a combination of art and science. Although many phases of automatic control theory can be expressed by precise mathematical relationships, the final control arrangement usually requires considerable effort by trial and error before the optimum control circuit is found. The failure of flotation operators to recognize that control circuits require study and plant experimentation before satisfactory operation occurs has led to a popular misconception that flotation plants simply do not lend themselves to automation. This widespread belief has been overcome to some degree in recent years by the numerous installations of automatic controls that have paid their way by increasing profits in terms of increased recoveries, lowered costs, or higher grade concentrates. WHY CONTROL ? Any form of automation must be justified in terms of ultimate return on in- vestment by improving quality, by increasing plant throughput, or by reducing the total operating costs. Generally speaking, automatic controls rarely re- place a mill operator. They assist the operator in holding important variables within predetermined limits. Large tonnage operations usually can justify a great deal of automation because an increase in one or two units of recovery results in enormous savings compared to the capital and operating costs of controls. DETERMINATION OF CONTROL The first questions in considering plant automation are: 1) What variables must be controlled? 2) What are the optimum levels of the variables? The optimum operating conditions for any process are those which maximize profits. Many of the variables active in flotation processing can be determined by experimentation in the laboratory or pilot plant 10. Although laboratory experiments can pinpoint variables, the true optimum conditions existing at plant level usually must be determined by plant scale experiments. In recent years, the concepts of detailed experimental designs in the laboratory, followed by plant experiments, have reached the stage of maturity where

Jan 1, 1962

By William Rawles

THIS report is the first of a series planned by The Mineral Inquiry, organized by the American Institute of Mining and Metallurgical Engineers to make factual studies of the world's mineral resources in their political and international relations. The efforts of The Inquiry are directed toward filling certain notable gaps in available information, without duplication of many other investigations touching this field which are being conducted by other organizations, public and private. Much of its work is indirect-suggesting topics for study by other individuals and organizations and aiding in their planning and correlation. The present report is designed to show the nationality of the commercial control of mineral resources, in addition to the geographic distribution of production by nation-in other words, the overlapping of political and commercial control. Detailed accuracy cannot be claimed for the figures presented. For some companies division of ownership by nationality has been very difficult to ascertain, as many companies are reluctant to dis-close the extent of their holdings in other corporations, and the impossi-bility of tracing all stock ownership is obvious. Also there are frequent changes in the distribution of stock control. The percentages given rep resent only the participation that has been identified definitely, even though it is known in some cases with fair certainty that larger interests exist, as, for instance, American participation in foreign chromite companies. In bringing together these figures we have had the cordial co-operation of the United States Bureau of Mines, the United States Geologi-cal, Survey, the Mineral Division of the Bureau of Foreign and Domestic Commerce, the Brookings Institution, and of many specialists connected with the mineral industries covered. The report does not cover the entire list of minerals: Coal, although it is one of the most important minerals, was omitted because not more than one or two per cent of the world's production comes from mines that are owned by companies foreign to the countries where the coal is produced. Others, such as gold, are omitted because sufficient data have not yet been accumulated. It is hoped that some of these may be covered in subsequent reports. It is not our purpose here to discuss the significance of the figures sub-mitted, but only to point out the general nature of the problems on which they have a bearing.

Jan 1, 1933

By D. J. Carney, R. L. Stephenson

A sampling technique has been developed for procuring a sample of sinter representative of the entire depth of the sintering bed. The sampling method involves the use of an open-bottom metal basket that rides on the grate of the sintering machine and when removed contains a sample of the sintered product. Additional data have been obtained to indicate that the tumbler test is a suitable means of measuring sinter strength. IN the last few years additional sintering facilities have been installed in both the Pittsburgh and the Chicago district of the United States Steel Co. Since the construction of these sintering plants made possible the use of higher percentages of flue-dust sinter in our blast-furnace burdens, it became important to study means of controlling the quality of sinter to obtain optimum results in the blast furnace. For controlling an operating process, it is necessary first to establish standards by which the quality of the product can be judged. For sinter, it appeared that an important property was its strength or its resistance to degradation during transportation and charging into the furnace. Consequently work was undertaken to establish a standard for sinter strength that could be used both for controlling sintering-plant operations and for correlating sinter quality with blast-furnace performance. The first problem in setting up a standard was that of procuring a sample that would be representative of the sinter made under any particular set of conditions at the sintering plant. Since the United States Steel Co. sintering plants discharge the finished sinter either into a large pit or onto a rotary cooler, the sinter becomes inseparably mixed with material sintered 2 hr before or 2 hr afterwards. For this reason the exact identity of the sinter is lost. A sample selected as the cooler is discharged, or as the sinter is removed from the pit, cannot be said to be truly representative of the sinter made at any specific time. Sampling The first attempt to procure a sample that would be representative of a specific sinter mix and of specific operating conditions was made by stopping the Dwight Lloyd sintering machine and removing an entire pallet full of sinter. This method, however, proved very difficult to perform and interfered considerably with the operation of the plant. To overcome this difficulty, a sampling method was devised by technologists at South Works enabling them to secure, without interrupting the sintering operation, a sample of about 1 cu ft of sinter, representative of sinter for the full depth of the sintering bed. The South Works method involves the use of a steel-frame-work basket. A typical basket is shown in Fig. 1. The basket has been used both with and without crossbars along the bottom. As long as the crossbars are in the same direction as the grate bars on the sintering machine they do not interfere with the sintering process. The basket is set on an empty grate of the Dwight Lloyd sintering machine before it passes under the swinging feed spout, see Fig. 2. When the basket is removed after it has travelled the length of the sintering machine, it contains the sample. Just before the basket is removed, the sinter is scored and chipped to facilitate removal of the sample from the sinter bed. A view of the basket after its removal is shown in Fig. 3. Although the sampling method was originally designed for use on a Dwight Lloyd sintering machine, it can also be used on the Greenawalt type of machine. When used on the Greenawalt-type machine, the basket is placed on the sintering grate before the charging car passes over it, and finally it is removed just before the pan is dumped. Testing After a method of obtaining a representative sample of sinter had been developed, the next step was to select a method of measuring its strength. The irregular shape and size of the sinter pieces precluded the use of a simple compression test for determining strength; consequently, the shatter test and tumbler test were investigated. To perform the shatter test, a sample of sinter, approximately 5 lb, is dropped from a hinged-bottom box at a height of 3 ft onto a steel plate. The broken sinter is sieve-analyzed after a specified number of drops. The tumbler test is performed with the use of a standard ASTM coke-tumbling drum. The drum is 3 ft in diam and is equipped with two lifter bars diametrically opposite one another on the inner periphery of the drum. The drum is rotated at a speed of 24 rpm for 200 revolutions, and after tumbling the sample is sieve-analyzed. To express as single numbers the results of sieve analyses after shattering or tumbling, the method suggested by R. E. Powers1 was employed. This method involved plotting the size of the sieve openings on a logarithmic scale and the cumulative per cent larger than each sieve on a probability scale as described by J. B. Austin.' By interpolating from the plotted data, which in most cases approximated

Jan 1, 1954

By T. B. Counselman

Probably the earliest concentration of iron ore in this country was carried on in the northeastern magnetite areas. Magnetic concentration was relatively simple and gave a concentrate that, after agglomeration, and in spite of being high in phosphorus because of the dry concentrating methods then in use, was satisfactory blast-furnace feed. Production from the northeastern magnetite area languished after the discovery and development of the Lake Superior ores, where there was seemingly an unlimited tonnage of high-grade ore, first the Michigan ores, and subsequently the still larger deposits of Minnesota. For years only the higher grade, direct shipping ores of the Lake Superior district were mined. Those of Michigan, and of the Vermilion Range in Minnesota, were hard ores and came principally from underground mines. The softer ores of the Mesabi came partly from underground mines, but mostly from the enormous deposits that could be worked by open-pit methods. The costs of ore from these open-pit deposits, even with the high initial cost of stripping, were so low that the underground mines of the Mesabi could hardly compete. The so-called Old Range ores, of Michigan and of the Vermilion. Range of Minnesota, were hard and lumpy, and opened UP the burden in the blast furnace, therefore making possible harder driving with greater output. Also, some of these ores were of such grade and physical characteristics that they were suitable for charge ore in the open hearth. These ores, therefore, commanded a price premium, and could compete with the softer, finer, but cheaper, Mesabi ores. The big tonnage reserves, however, are on the Mesabi. and it is these big open-pit deposits that constitute our stock pile of iron ore, from which we are drawing so heavily during this war period. On the western end of the Mesabi the ore was found to be high in silica, and not suitable as furnace feed. As early as 1902, attempts were made to concentrate this so-called wash ore and by 1910 the first washing plant was put into operation. The Process was very simple, consisting essentially of a sizing and washing operation, with scalping screens, logwashers, and tables, which later were replaced by classifiers. Ore particles finer than 100 mesh were deliberately wasted, because these fines were undesirable in the furnace. Fortunately, these tailings were impounded, and already are being reworked. Before long some of the low-grade ores began to require more elaborate treatment than the simple washing operation and, tables having been discarded because of their low capacity, in favor of classifiers, jigs were next introduced. These were able to discard coarser pieces of tailing than classifiers. jigs are in active use today, various improvements having been made in their design and application. Various other machines and methods of concentration have been tried from time to time, and have in turn been discarded for more improved processes. The latest and most important process that has been

Jan 1, 1947

By T. B. Counselman

Probably the earliest concentration of iron ore in this country was carried on in the northeastern magnetite areas. Magnetic concentration was relatively simple and gave a concentrate that, after agglomeration, and in spite of being high in phosphorus because of the dry concentrating methods then in use, was satisfactory blast-furnace feed. Production from the northeastern magnetite area languished after the discovery and development of the Lake Superior ores, where there was seemingly an unlimited tonnage of high-grade ore, first the Michigan ores, and subsequently the still larger deposits of Minnesota. For years only the higher grade, direct shipping ores of the Lake Superior district were mined. Those of Michigan, and of the Vermilion Range in Minnesota, were hard ores and came principally from underground mines. The softer ores of the Mesabi came partly from underground mines, but mostly from the enormous deposits that could be worked by open-pit methods. The costs of ore from these open-pit deposits, even with the high initial cost of stripping, were so low that the underground mines of the Mesabi could hardly compete. The so-called Old Range ores, of Michigan and of the Vermilion. Range of Minnesota, were hard and lumpy, and opened UP the burden in the blast furnace, therefore making possible harder driving with greater output. Also, some of these ores were of such grade and physical characteristics that they were suitable for charge ore in the open hearth. These ores, therefore, commanded a price premium, and could compete with the softer, finer, but cheaper, Mesabi ores. The big tonnage reserves, however, are on the Mesabi. and it is these big open-pit deposits that constitute our stock pile of iron ore, from which we are drawing so heavily during this war period. On the western end of the Mesabi the ore was found to be high in silica, and not suitable as furnace feed. As early as 1902, attempts were made to concentrate this so-called wash ore and by 1910 the first washing plant was put into operation. The Process was very simple, consisting essentially of a sizing and washing operation, with scalping screens, logwashers, and tables, which later were replaced by classifiers. Ore particles finer than 100 mesh were deliberately wasted, because these fines were undesirable in the furnace. Fortunately, these tailings were impounded, and already are being reworked. Before long some of the low-grade ores began to require more elaborate treatment than the simple washing operation and, tables having been discarded because of their low capacity, in favor of classifiers, jigs were next introduced. These were able to discard coarser pieces of tailing than classifiers. jigs are in active use today, various improvements having been made in their design and application. Various other machines and methods of concentration have been tried from time to time, and have in turn been discarded for more improved processes. The latest and most important process that has been

Jan 1, 1947

By Gerald V. Jergensen

Does an idea have merit? What does it cost to implement? Can the concept be implemented successfully? The ultimate proof is to try, then see. However, when there are many millions of dollars at stake, blindly building and trying requires considerable courage. Owners and investors in retrospect might choose other less complimentary words. So we might ask, "How might we establish the feasibility of an idea or concept before committing large sums of money to the ultimate test?" From this basic and prudent question, has evolved the engineering concept of the feasibility study. A feasibility study is simply a systematic evaluation of an idea or concept to determine the prospects for success. In a literal sense, a feasibility study considers an idea in terms of its data base, "builds" the idea on paper, "operates" that idea, calculates the cost and benefits, then measures the probable success in terms of some economic, technical or financial standard. Feasibility studies can be quite modest in scope yet provide useful insights as to the viability of an idea. A study might be initiated only to examine the completeness or validity of the metallurgical data base. Another study could be a search for a workable idea or solution to an already-identified possibly troublesome problem. In this latter case, the question, "Will it work?" may be far more important than, "How much will it cost?" Feasibility studies are sometimes global in scope, involving several dozens of specialists and examining an entire "grass roots" mining complex. Other studies may be less ambitious but equally important in examining an expansion proposal or developing new operating techniques. Studies may be commissioned to remove plant bottle-necks, solve maintenance problems and so on. The terms study and feasibility study are used interchangeably in this chapter. They denote a systematic method to examine a proposed concept or idea. DATA BASE Typically, studies are initiated with a minimum amount of specific information and a maximum number of assumptions. As the work proceeds and the data base expands, assumptions are replaced

Jan 1, 1982

By Howard C. Pyle, John E Sherborne

Core analysis is a recent development in the field of petroleum technology. The earliest work on this subject was done in connection with evaluating and planning secondary oil recovery by water-flooding. Present-day analysis of sands of flush fields requires new and independent interpretations of the data provided by cored material. Particular attention is being paid to the development of rapid, routine methods for measuring physical characteristics of sandstone, such as permeability, porosity and grain size, as well as the sand's fluid content. Permeability may be defined as the fluid-passing capacity of a rock. For a sandstone to be permeable it must be possible to pass a measurable quantity of fluid through the material in a finite period of time. The common unit of permeability is the darcy, which may be defined as the rate of viscous flow, in milliliters per second, of a fluid of one centipoise viscosity through a porous medium having a cross section of one square centimeter, under a pressure gradient of one atmosphere (76.0 cm. Hg) per centimeter.' For convenience the subunit millidarcy, or one-thousandth darcy, is often used. Porosity is defined as the fluid-containing capacity of a rock and is usually expressed as a percentage ratio of the total pore volume to the rock or bulk volume. Since measurement of only the effective or communicating pore volume is often made, porosities are distinguished as total or effective.2,3 Net effective porosity is defined as the net pore volume available for oil and gas. Oil and water content of sand is measured and expressed either as the percentage saturation of the total pores or of the bulk rock. The oil content may also be expressed as the percentage saturation of the net effective pores. In connection with water-flooding, methods of core analysis were developed to furnish data that could be used in determining the quantity of recoverable oil14-6 and the probable rates at which various sands or divisions of a sand open to the wells would take water or produce oil. In flush fields, the analytical data are used to predict the productivity of a cored interval. They indicate the presence of oil, gas and water and may

Jan 1, 1939

By Howard C. Pyle, John E. Sherborne

Core analysis is a recent development in the field of petroleum technology. The earliest work on this subject was done in connection with evaluating and planning secondary oil recovery by water-flooding. Present-day analysis of sands of flush fields requires new and independent interpretations of the data provided by cored material. Particular attention is being paid to the development of rapid, routine methods for measuring physical characteristics of sandstone, such as permeability, porosity and grain size, as well as the sand's fluid content. Permeability may be defined as the fluid-passing capacity of a rock. For a sandstone to be permeable it must be possible to pass a measurable quantity of fluid through the material in a finite period of time. The common unit of permeability is the darcy, which may be defined as the rate of viscous flow, in milliliters per second, of a fluid of one centipoise viscosity through a porous medium having a cross section of one square centimeter, under a pressure gradient of one atmosphere (76.0 cm. Hg) per centimeter.' For convenience the subunit millidarcy, or one-thousandth darcy, is often used. Porosity is defined as the fluid-containing capacity of a rock and is usually expressed as a percentage ratio of the total pore volume to the rock or bulk volume. Since measurement of only the effective or communicating pore volume is often made, porosities are distinguished as total or effective.2,3 Net effective porosity is defined as the net pore volume available for oil and gas. Oil and water content of sand is measured and expressed either as the percentage saturation of the total pores or of the bulk rock. The oil content may also be expressed as the percentage saturation of the net effective pores. In connection with water-flooding, methods of core analysis were developed to furnish data that could be used in determining the quantity of recoverable oil14-6 and the probable rates at which various sands or divisions of a sand open to the wells would take water or produce oil. In flush fields, the analytical data are used to predict the productivity of a cored interval. They indicate the presence of oil, gas and water and may

Jan 1, 1939

The only technical session on Thursday was a continuation of the Symposium on Pyrometry. The members not attending the symposium -made the trip to La Salle. They were welcomed by the Mayor, to whose speech Major Arthur S. Dwight briefly responded. After luncheon the party divided and was taken by automobile to the various chosen points of interest, such as the cement works, the various zinc smelters, the coal mines, and underground cement-rock mines, where underground steam shovels were operating, etc. A special scenic trip was arranged for the ladies. The party returned by special train to Chicago, arriving at 7:30. Those desiring to visit the coal mines at Franklin and Macoupin Coun-ties left by train that evening on a special car for Benton, and were piloted through the field by Mr. Putnam, superintendent of the Old Ben Coal Corpn., Mr. Carroll, assistant general superintendent of the Chicago, Wilmington & Franklin Coal Co., and Carl Scholz, general manager of the Vallier Coal Co. Through the courtesy of the various railroads the visitors were furnished a special coach which took them to the various mines with the least delay and enabled them to see more than would be otherwise possible. Mines 8 and 9 of the Old Ben Coal Corpn., at West Frankfort, were first visited; thence the party proceeded to Orient mine of the Chicago; Wilmington & Franklin Coal Co., where luncheon was served, and then proceeded to Vallier, where both the top and the under-ground workings were inspected. The party returned to. Benton and from there proceeded in automobiles to inspect the washery plant of the United States Fuel Co. at that point; and boarded the train reaching Chicago Saturday morning. Several left Benton for their homes without returning to Chicago.

Jan 11, 1919

By L. B. Berger, W. P. Yant

This paper presents evidence of the general occurrence of methane in a large number of the coal fields of the United States and substantiates the apparent unnecessary differences in the ventilation requirements and codes in the various states, as was brought to the attention of the Committee on Mine Ventilation of the American Institute of Mining and Metallurgical Engineers at its Pittsburgh meeting in October, 1925, by J. A. Garcia. The data in his report have been compiled from the files of the Gas Laboratory of the Pittsburgh Experiment Station of the Bureau of Mines and represent samples collected throughout the various states and submitted for analysis by its engineers, also by mine operators and State mining departments, since 1911. Several thousand analyses were available but most of them were rejected because they represented abnormal conditions, undefined place of sampling, special investigations, or duplications in the same mine. Only those samples were included which, without reasonable doubt, were ascertained to fall within three major classes, namely, main return, air splits, and face and rooms of live workings. In the case of air splits, and face and room samples, only the one which contained the highest percentage of methane found in a given mine was taken. OCCURHENCE OF METHANE IN COAL MINES OF THE UNITED STATES Obviously it is not feasible to present the detailed analytical data here and accordingly these data have been compiled into groups in a manner which it was thought would bring out clearly their significance. These are shown in Table 1 which includes the analyses of 310 samples of return air of approximately the same number of coal mines in 19 states. Because of changes in ownership and names the exact number could not be ascertained. The table also includes 337 samples from air splits and 263 from the face and rooms of some of the same mines represented by return air samples and from other mines in these states. A total of more than 400 mines are represented by Table 1.

Jan 1, 1927

By Haydn H. Murray

The term clay is somewhat ambiguous unless specifically defined because it is used both as a rock term and as a particle size term. Actually most persons using the term clay realize that it has a double meaning and in most instances define it. As a rock term, clay is difficult to define because of the wide variety of materials that compose it so that the definition has to be general. Clay is a natural, earthy, fine-grained material composed largely of a limited group of crystalline minerals known as the clay minerals. Many definitions state that a clay has the property of plasticity when wet, but some clays are not plastic, i.e., halloysite and flint clay; however, most clay materials are plastic when wet. As a particle size term, clay is used for the category that includes the smallest particles. The maximum size particles in the clay size grade are defined differently on some grade scales. Soil investigators and mineralogists generally use 2 microns as the maximum size. The Wentworth scale' defines clay as material finer than approximately 4 microns. Grim' has found it convenient to use the term clay material for any fine-grained, natural, earthy, argillaceous material and in this way can include clays, shales, or argillites, and some soils if they are argillaceous. Even though no standard definition of the term clay is accepted by geologists, agronomists, engineers, and others, still the term is generally understood by all who use it. Clay is an abundant natural raw material and has an amazing variety of uses and properties which will be discussed in this chapter. In order to understand better the relationships between the clays and their uses, a brief discussion of the structure, chemical composition, and identification of the clay minerals is given. Mineralogical Composition of Clays Clays are composed of certain groups of hydrous aluminum, magnesium, and iron silicates that may contain calcium, potassium, and other ions, which are called the clay minerals, and other minerals of variable composition, which are nonclay minerals. Both clay minerals and nonclay minerals influence the properties of a clay material. In order to understand the relationship between clay minerals and the properties of a clay material, a short summary of the structure and composition of clay minerals is necessary. Any scheme of classification tends to impose a certain rigidity and as new and additional data become available it is necessary to revise classifications. Brindley3 has discussed the classification and structural mineralogy of clays in very lucid fashion and chose a classification based on structural features and chemical composition. Grim2 proposed a tentative classification which is based on the structural attributes of the various clay minerals. This classification is relatively simple and workable, and is shown as follows: I. Amorphous Allophane group II. Crystalline A. Two-layer types (sheet structures composed of units of one layer of silica tetrahedrons and one layer of alumina octahedrons). 1. Equidimensional Kaolin group kaolinite, dickite, nacrite 2. Elongate Halloysite group

Jan 1, 1960

By L. A. Mekler

The recirculating furnace is primarily a heating apparatus of the convection type in which the heat-absorbing surfaces are heated by a mixture of fresh products of combustion and a portion of the combustion gases that have already given off a part of their heat in their previous passage over the heat-absorbing surfaces. In its basic conception, the recirculating furnace can be considered as a closed thermal system in which the heat-absorbing surfaces are constantly swept by a fixed quantity of products of combustion at a given initial temperature with the gases being constantly returned to the furnace and reheated before they again enter the heating zone. Gases equal in amount to those produced by the fuel burned to reheat the circulating gases are constantly ejected from the system to the stack. The recirculating furnace is the most suitable apparatus for heating by convection where low furnace temperatures must be maintained and where only a small portion of the available heat is taken out of the gases, particularly where the maximum allowable furnace temperature is low and where the final temperature of the gases is only a few hundred degrees below their initial temperature. In such cases, recirculation not only provides a method of reducing the rather high combustion temperatures of the fuel when burned without a large amount of excess air, but, by returning to the furnace the heat content of the gases at their final temperature, recovers a large portion of heat that otherwise would have been lost through the stack. The convection-type oil still is particularly suitable for the application of flue-gas recirculation. In an oil still, the heating of the oil is accomplished by applying to the tube surfaces a given quantity of heat of a certain predetermined quality, usually with the initial temperature of the gases not over 1500" F. as measured by thermocouples placed above the tube bank. To obtain the full benefit of the heating surface of the coil, the final temperature of the gases, after passing over the coil, is kept 200" to 300" higher than the temperature of the incoming oil. This final temperature varies from 500" F. for a topping still with only a slight or no

Jan 1, 1928