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By James Lee Hibbard, Doraiswami Ramkrishna

A population balance model accounting for the transient variations in drop size distributions in a stirred liquid-liquid system is analyzed for its effect on chemical reaction conversion in a stirred, batch reactor. The analysis is applied specifically for phase transfer catalytic reactions, which indicates that transient effects of evolution of drop size distributions may be important in such systems.

Jan 1, 1981

By Alfred E. Hunt

The late Alexander Holley said, on returning from a careful study of the relative merits of the Bessemer and the open-hearth processes, as shown in the best European practice, that, in this country, the open-hearth process would live to attend the funeral of the Bessemer ; and he said this several years ago, when in this country the Bessemer plant and practice had been developed to far outstrip that abroad, and when, proportionately, it had reached an advancement much beyond the improvements in open-hearth plants and practice. At the same time, the prevailing idea in the metallurgical world, a few years ago, seemed to be in favor of the substitution of Bessemer for open-hearth steel for most of the higher qualities, and Bessemer enthusiasts loudly proclaimed, that as good steel for all purposes could be obtained by their favorite process as by the open-hearth. It was, in fact, confidently prophesied that very soon tool-steel and similar grades, which consumers had learned to specify, in ordering, to be made by the crucible process, would by common consent be made by the Bessemer, as best adapted to give the desired results. But these expectations have failed to materialize; not only do the crucible people keep on in the even tenor of their way and talk with pride of their comparatively large outputs of " hundreds " of tons per month, as usual, but the open-hearth people have kept fast hold of their original domain of nearly the entire amount of sheared plates, of locomotive tires, of large forgings, spring-steel, agricultural steel, steel castings and the like. Further, owing largely to one of the great advantages of the Bessemer process, which is also one of its inherent dangers, namely, its large output, it has also fallen into considerable disrepute for structural purposes. Not a few experienced engineers are now stipulating in their specifications that Bessemer steel will not be allowed to be used, especially for tension-members.

Jan 1, 1888

By Charles Weaver

DURING the past few years there has been considerable activity in prospecting for oil and gas in several parts of western Washington. From time to time seepages of oil or emanations of gas have been reported from various places. Several companies have been organized for the purpose of drilling, but only a part of these have actually begun operations. In certain localities very small seepages of oil occur, but up to the present time no oil or gas in commercial quantities has been obtained. In order to determine the conditions which may be favorable or unfavorable 'to the occurrence of petroleum it becomes necessary to know the character and extent of the geological formations in which such deposits might occur. In other regions where producing wells have been developed it is possible to know what formations contain the oil mind what structural conditions influence its concentration in reservoirs or zones. It is usually possible to determine those strata which contained the a materials from which the petroleum may have been derived and also the position and distribution of the more porous sandstone belts into which it may have collected. Detailed stratigraphic surveys, may even determine the depth at, which a certain known oil-bearing zone may be tapped at any particular place. It is also possible to recognize those formations which are presumably barren of oil, as well as those which are absolutely so.

Jan 7, 1915

By C. G. Rhodes

A technique for producing etch pits in uranium monocarbide has been developed. The pits, which are assumed to be associated with dislocations, appear individually and as arrays delineating sub-boundaries, as seen in Fig. 1. The samples used were single crystals prepared by the technique described by Nadler.* Uranium

Jan 1, 1963

By Eugene S. Perry

The most outstanding event in oil and gas development in Montana during 1936 was the discovery of oil in the Baker-Glendive gas field, in the extreme eastern part of the state. Other notable achievements were small extensions in the Cut Bank oil field; continued favorable results of acidization in the Kevin-Sunburst oil field; and the discovery of oil and gas in commercial quantities about 20 miles southwest of Billings, on what is known as the Mosser dome. Several wildcat wells were drilled. For the coming year of 1937, it is anticipated that the main activities will be confined to drilling in or near known fields. During 1936 Montana had seven fields producing oil, but over 95 per cent of oil production came from four fields, which in order of importance are: Cut Bank, Kevin-Sunburst, Cat Creek and Pondera. Total production for the state was 5,850,893 bbl., which is 1,251,761 bbl. more than the total for 1935. Natural gas was produced and marketed from eight fields, most important being Cut Bank, Baker-Glendive, Kevin-Sunburst and Dry Creek. These four fields accounted for over 85 per cent of total state gas production, which is slightly greater than the 1935 production of nearly 18 billion cubic feet. Increase in gas consumption is due in part to increase in smelter operation. More detailed information pertaining to the various fields is given in Table 1. In the Baker-Glendive field a test 8186 ft. deep, 15 miles southeast of Baker, was completed by the Montana-Dakota Utilities Co. in 1936. The first gas-bearing sandstone (Judith Hiver horizon, Upper Cretaceous) was found at a depth of 528 ft., and a second sand at 1167 ft. Sandstones of the Dakota formation, in which occurred water, were found from 3724 to 3853 ft. White sandstone correlated with the Tensleep (Minnelusa) formation of Pennsylvanian age was found from 5631 to 5751 ft. deep. The lower 1900 ft. of the well (below 6278 ft.) was essentially in limestone and dolomite, and information on correlation of formations in this mass of sediments is not available at this time. The upper portion of this part of the well contained much anhydrite. Cherty and dolomitic limestone below 7000 ft. may be equivalent to limestones of the Madison formation. The thickness of strata beneath the Dakota formation was

Jan 1, 1937

Just three years after researchers announced its development, Dravo is putting the finishing touches on a new $60-million Thiosorhic lime mine/kiln complex near Maysville, Ky. Electric utilities in western Pennsylvania and Ohio have already signed long-term contracts for over three-quarters of the projected 907 000-t/v (1-million-stpy) production. Thiosorbic lime, a flue gas desulfurizing agent, proved in industrial testing that at high emission levels (greater than 3000ppm SO2) it could be twice as effective in SO2 capture as conventional lime, while eliminating the major problem of scaling and plugging of scrubber equipment.

Jan 4, 1977

By V. Sobitsky

In open cast mining of coal, the cost per ton of output is four to five times less and labor productivity five to six times higher than in under- ground mining. This is why the coal industry of the USSR is oriented toward giving priority to the development of open cast coal mining. Deposits of coal which lend themselves to open cast mining in the USSR are enormous, with 90% of them located in the eastern part of the country. The technique is by no means limited to the eastern part, however-despite wide variations in climate, other parts of the Soviet Union also use open cast mining. The occurrence and type of coal deposits in the USSR vary greatly. Some of them are flat coal seams 2 to 40 m thick, and a few are even thicker. There are also deposits having a complex mode of occurrence, such as a series of seams of different thicknesses with angles of dip varying from slightly inclined to steep, often with dislocations. Overburden materials are quite diverse with regard to physical and mechanical properties. There are three kinds encountered-loose or unconsolidated overburden, medium-hard material, and hard rock. The stripping ratio, i.e., the amount of cover per ton of mined coal, varies from 1 to 12 cu m per ton. SYSTEMS OF MINING The great diversity of natural conditions has brought forth a variety of technologies and techniques in the open cast mining of coal. In open cast practice, the following systems of mining are used : (1) a transportation system in which the overburden is transported to spoil banks by rail or by truck; (2) a system with direct disposal of overburden, the rocks being dumped on spoil banks with a stripping excavator; and

Jan 1, 1969

By David P. Hale, Guy W. Jordan

HIGH-IRON cements have a number of advantages over cements carrying little or no iron. The presence of iron in Portland cement aids in the manufacture of the cement and also imparts certain advantageous physical properties to the finished product. In manufacture, the presence of iron lowers the fuel consumption, increases the ease of proper burning, and lessens the destructive action of the charge on the kiln refractories. In the finished cement the presence of iron reduces the expansion and contraction, adds strength, adds increased resistance to freezing and thawing, and increases the resistance of the cement to sea or sulphate waters. During the past few years the construction of numerous dams throughout the Southeast by the Tennessee Valley Authority has stimulated the production of high-iron cements. At present a great number of specifications call for an iron cement, and the industry is supplying this demand with a Portland cement carrying approximately 5 per cent iron oxide. Several manufacturers are now making practically all of their cement of this type and a number of others manufacture it as a special cement over short periods to meet demands from the Tennessee Valley Authority and other buyers. The recent increase in the use of iron in Portland cement has created a market for iron products that previously was nonexistent. The chief sources of supply for the cement manufacturers at present are iron sand, iron sinter and slag, and ocher. The Copperhill mining district, Tennessee, supplies both iron sinter and slag for use in cement. The Cartersville district supplies iron sand, ocher, and some iron resulting from the magnetic separation of iron from barite. The advantages of these products vary according to the chemical properties of the raw materials and the methods of handling used by the different manufacturers. Where the iron is to be handled by conveying belts and in hopper cars, the iron

Jan 1, 1939

By Thomas J. Ferree

The principle mineral concentration practices today can be divided into three basic process categories: magnetic separation, flotation and gravity separation. The basic processes have been in use for many years with only limited changes occurring in equipment design or process technique. In general, equipment and process techniques have been altered only after a need for change has developed. With exceptions for changes necessitated by new environmental laws, most equipment and process improvements have evolved in accordance with the desire to concentrate larger quantities of material at lower costs. The basic result has been the development of larger capacity equipment, to wit: larger flotation cells, larger blast furnaces, larger haulage equipment and larger chemical process equipment. However, there has been practically no changes in the size of spirals, tables, jigs, or-within limits- magnetic separators. (The exception being high-intensity magnetic separators). Consequently, a "new" device has entered the scene which may fill a void in the gravity separation field. It is called a Reichert cone concentrator.

Jan 3, 1973

By T. W. Healy, P. Somasundaran, K. Ananthpadmanabhan

Hydrolyzable surfactants such as fatty acids and amines undergo, in addition to micellisation and precipitation, various associative interactions in aqueous solutions to form ionomolecular complexes such as acid-soap, dimers, etc., depending upon the solution conditions such as pH. The interaction of these collector species with the mineral surface and with other dissolved species in solution will play a significant role in determining the interfacial processes such as adsorption and flotation. Marked differences in the hydrophobicity imparted to the mineral surface depending upon the solution conditions such as pH can be attributed to possible differences in surface activities of the foregoing complexes. This aspect of solution chemistry of flotation system is discussed here for two widely used collectors, namely, oleic acid and dodecylamine. Equilibrium species distribution diagrams, based on the available literature data and on estimates of energy of interactions between molecules, have been obtained for oleic acid and dodecylamine solutions.

Jan 1, 1980

By Persifor Frazer

MR. Theodore D. Rand has made some interesting observations on the serpentines of Chester and Delaware counties, Penna., in which he suggests that the outcrops of this rock are detached from each other, and that while a comparatively narrow belt, running nearly east and west, mill include them all, the strike of each outcrop differs considerably from the direction of this narrow belt; and that it results that these isolated exposures exist on the map, as it were, in echelon, the easternmost end of each lying northwest of the western extremity of its neighbor. As he elsewhere remarks, this is important, if established, and the writer spent a day or two recently on the ground in the study of this phenomenon. One thing would seem to follow from such a state of facts, viz., that this serpentine at least must have been of secondary origin, for it is difficult to conceive of a rock which occurs intercalated in numerous horizons of a different formation, and agreeing with the latter in bedding, unless the former were an altered product of the latter. It is true that one might account for it by the supposition of an original unconformable deposit, which had been broken by a number of faults and distorted by throws to the northwest; but this hypothesis would do violence to the observed facts relating to the measures along with which the serpentine occurs, and in which no such distortion has been observed. * Thus for determining, by evaporative test, the calorific power of a coal, the ultimate constitution of which is known, it is requisite, that, besides the quantity of coal consumed and the weight of the water evaporated, the temperature and chemical composition of the escaping gases, or gaseous residue, shall be quantitatively determined, the same as solid residues of ash and unconsumed fuel. In observance of such requirements, the Heizversuchstation of Munich has been in operation since 1879. This consists of a permanent boiler plant, constructed on the principle of the calorimeter, with special provision for avoiding errors from loss of heat—snch, namely, as arise from radiation and conduction, and from the varying proportions of water in steam.—Muck. Steinkohlen-Cliemie, 1881, 146. See Proc. Min. and Geol. Sect., Acad of Nat. Sci., 1850 and 1881, pp. 9 and 28.

Jan 1, 1884

The failure of finely-divided sulfide particles to respond to flotation has resulted in a significant loss of our natural resources. As mentioned by Professor Arbiter, the overall recovery of copper from porphyry copper ores is generally between 80 and 85 percent. The recovery of copper sulfides from these ores is about 90 percent, the difference in these recoveries being due to failure of oxide copper minerals to respond to flotation. The 10-percent loss of sulfide copper has not been studied. Losses are known to be in the fractions finer than 74 microns, but the sizes that are not responding to flotation have not been established. In the case of molybdenite, however, it is known that particles finer than about five microns are not recovered. Work in other systems, notably the hematite-quartz system, has shown that good flotation of very fine particles from natural ores is possible (1, 2). The size distribution of one ore that was researched is given in Table 1, and as shown, approximately 50 percent of the ore was finer than 10 microns. Flotation experiments were conducted with this ore, which contained 45 percent iron, utilizing octyl hydroxamate as collector and without any desliming (1). The results of these experiments are presented in Table 2. From the standpoint of mechanisms of collector adsorption, similarities exist between those occurring in the hydroxamate-hematite system and many xanthate-sulfide systems. .This is, multilayers of ferric hydroxamate are present on hematite under flotation conditions (1,3).

Jan 1, 1979

By H. R. Collins

The purpose of pulverizing coal before burning it is to make available every heat unit it contains. Machinery has been developed which will pulverize coal in one operation, delivering it to bins in front of the furnaces at an expenditure of about 17 hp.-hr. per ton, in a medium-sized plant. The cost of the operation depends upon the amount of moisture that must be expelled before pulverizing, the cost of labor, and the cost of coal delivered at the plant. At a small plant, requiring a pulverizer with a capacity of only 1/2 ton per hour, the cost per ton pulverized will naturally be greater than at a plant requiring the largest pulverizer, with a capacity of 7 tons per hour. :The first step is to reduce large lumps to a size suitable for drying uniformly, before passing to the pulverizing mills; this is done in rolls, at a single pass. The second step is the elimination of moisture, in order to facilitate pulverizing to great fineness, while also increasing the heating effect and the temperature attainable when the coal is burned. There are other mechanical advantages in the handling of dried coal. Driers are now manufactured which are able to eliminate moisture without distilling any of the volatile combustible matter in the coal; they are fired by hand or with pulverized fuel. The heat first surrounds the shell of the drier, being confined within a chamber where complete combustion takes place; the heated gases are then led through a duct to the discharge end of the drier and enter the inside of the shell at a temperature not exceeding 300" F. This temperature is maintained by the operator and is indicated by a pyrometer. Volatile combustible matter is not likely to be distilled until the temperature rises above 400" F. On discharging from the drier, the coal is usually passed over a magnetic separator in order to prevent pieces of iron from going to the pulverizer. Two types are used: a magnetic pulley which automatically discharges its collection of iron, and a lifting type, from which the iron is removed by hand when convenient. In the operation of pulverizing, the coal should preferably be reduced until 95 per cent. will pass through a 100-mesh and 70 per cent. through a 300-mesh sieve. Such a product is obviously an almost impalpable powder.

Jan 1, 1920

By K. C. Heald

THE places where, yesterday, oil was unknown contain tomorrow's fields. Unquestionably, some states that now yield little or no oil have great potentialities, and developments in these states, although perhaps of less immediate interest than those in regions where great pools now exist, may easily be of greater ultimate importance than the results of exploration closer to known fields. Not long ago, Montana had only a quarter of an oil pool, and that was regarded by many as an accident that had strayed from Wyoming. More recently, the northern line of Louisiana was a dead line that would not be crossed by any Louisiana operator who valued his reputation for sanity. Within the past few months, Colorado has shown that it is far from being a negligible factor in the oil supply of the Rocky Mountain states, and it is now known that western Kansas, long shunned by many reputable geologists and operators, should be reckoned with. There may be a vast difference between what a wildcat well yields and what the well signifies. The fact that no commercial production is encountered may be lamentable and may well be disastrous to an individual or a company, but the same well that spells ruin to one may convey to another the information that will result in opening a new field. In presenting the conclusions, in this paper, the writer recognizes fully the possibility of erroneous deductions, particularly since he has had contact with only a few of the wells that are mentioned. Information comes principally from the scout. maps and files maintained at the Geological Survey by M. E. Latimer and G. K. Drach, without whose cooperation this summary would not be possible, supplemented by some personal contact and second-hand information gained by. conversation and correspondence. However, it is felt that the data contain few errors, and that the conclusions are at least reasonable.

Jan 3, 1924

By Abram S. Hewitt

GENTLEMEN : If my first words were other than those of thanks for the high honor of being called to preside over the American Institute of Mining Engineers, I should do injustice alike to you and to my own sense of the obligation, under which I have been placed by your voluntary choice. When the position was first suggested to me, I resolutely declined to allow the use of my name, on the ground that, by training and occupation, I was not entitled to this honor, which, it then seemed to me, should be conferred only on a professional engineer. In fact, the history of the Institute, which had honored itself, as well as my distinguished predecessors, David Thomas, Rossiter W. Raymond, and Alexander L. Holley, by elevating them to its highest office, seemed to indicate the line and the limit of safe precedent, in which I did not then see how I could be included. But my scruples were finally removed by the consideration that, as in the course of human industry, the pioneer, of whom Mr. Thomas was so marked a type, must precede the mining engineer, so fitly personified in Dr. Raymond, and be followed by the mechanical engineer, whose incarnation we behold in Mr. Holley; so all these must be supplemented by the man of affairs and finance, in order that "enterprises of great pith and moment" may be prosecuted to a successful issue. I felt, therefore, that I had no longer any right to resist your preference, or to deprive myself of what I must regard as the crowning honor of an active career. On an occasion like the present it seems appropriate to review the history in this country, during the last hundred years, of those industries which the Institute of Mining Engineers specially represents. There is much in the story with which other members of this body are more familiarly acquainted than myself; yet I fancy that to all of them, and not less to our distinguished and most heartily welcome guests from abroad, a comprehensive outline of the progress of mining and metallurgy in the United States will prove interesting. I ask your attention, therefore, to a condensed account of that subject, embracing a statement of the beginnings of the industry on our shores, of the notable events attending its increase, and of its present

Jan 1, 1877

By W. M. McCardell, W. O. Winsauer, M. Williams

The mechanism by which an electrical potential difference is developed between two salt solutions separated by shale is shown to be a consequence of the electrical double layer of the shale surfaces. A mathematical derivation is presented to show -the dependence of the potential on the shale characteristic.? and on the concentration of the salt solutions. The equations developed describe adequately the potential-concentration behavior of a long shale core. The equations also describe the variation of potential of sand-shale mixtures with variation of clay content. Ion adsorption i* an important factor in he developments of the surface charge on the shale. and electrical resistivity and ion transference number data are emlployed to estimate the increase of surface charge with concentration. Since the potential is shown to be dependent on the characteristics of the particular .system. water salinities estimated from the potential log by previously proposed methods may be low in some rase;. INTRODUCTION That the electric well log exists today may he attributed to the ingenuity of the Schlumberger brothers who adapted to the logging of wells techniques which were originally developed as surface prospecting methods for the location of ore bodies Empirically it was found that the potential curve of the electric log usually gave values for clean sands which were negative with respect to the values for shales. It was suggested that the potential was responsive to porosity. It was postulated in explanation? that the potential was the sum of a streaming potential, which differed for sands and shales, and of an "electro-chemical" potential of undetermined origin. Mounce and Rust in 1943 showed that the streaming potential is small in most cases and that the potential is generated by a process in which shale and a salinity difference play-essential party. Dickey.:' in the same year, concluded that the potential is dependent upon adsorptive properties of reservoir rock. Wyllie in 1949. and Wyllie and Patnode, in 1950, measured the potential-: between two salt solutions separated by barriers of either naturally-compacted or artificially-compacted shales and concluded that the potential can be expressed by where E is the potential R is the gas content F is Faraday's constant T is the absolute temperature are the activities of the two uni-univalent solutions These authors postulated that shale. in the ideal case is impermeable to the migration of negative ions. Any potential less than the "ideal" shale potential was considered to be due to imperfections in the shale barrier. Although the studies by Wyllie and Patnode of the development of the shale potential are fairly recent. investigators in fields other than well logging have discussed the mechanisms responsible for analogous potentials over a period of several decades. Although it is evident that much thought has been devoted to the question of the origin of the potential observed in wells, it is also apparent that all of the explanations presented to

Jan 1, 1953

By Charles Albert Ashburner

Natural gas has been known to exist for many years in the St. Lawrence Valley, between Quebec and Montreal, and more partirularly in the vicinity of Louisville and Three Rivers, 74 and 94 miles respectively northeast of Montreal, and 98 and 78 miles respectively southwest of Quebec; the distance from Montreal to Quebec along the St. Lawreuce River being about 175 miles. It was not until 1880 that any practical explorations were begun with the hope of finding gas in sufficient quantities for commercial uses. In this year Messrs. Piret and Genest, of Three Rivers, sank a well near St. Maurice to a depth of 50 feet, where solid rock was encountered. A similar well was drilled through the glacial and allavial drift, in the same district, in 1883, by the Messrs. Renaud Freres and Dubois, to a depth of 70 feet before solid rock was encountered. In this latter well a strong flow of gas was obtained. The gas was an outflow from a very limited reservoir in the porous glacial gravel, which had been filled from the gas resulting from the decomposition of vegetable remains, which had been buried in the gravel at the time of its deposition. Subsequently, other wells were sunk in the same way, with the hope of getting gas in commercial quantities from similar reservoirs. Commercial Gas.—By gas in commercial quantities I mean gas in such quantity that, if utilized with proper care and economy, it would generate steam at a cost below the cost at which the same duty could be obtained from the use of coal or wood at current prices, and that

Jan 1, 1890

By W. F. Dietrich

Mineral fillers are relatively inert chemically under the conditions of use but have physical properties* that modify those of the materials • The properties. uses, and other data on 15 classes of important *The pro listed in the second edition of Industrial Minerals and Rocks.l A third edition of this reference is in preparation. in which they are incorporated. The mineral fillers considered in this article are asbestos, barite, clays, diatomite, crushed limestone, limestone whiting and lime, mica, silica, talc and soapstone, and pyrophyllite. Slate and stone, other than limestone and its derivatives, are excluded because, even though used in large quantities, they are exceptionally low-cost materials generally produced close to the area where they are used. Carbon black is excluded because it is manufactured from natural gas and more than 90 pct of the output is used in rubber; hence the factors for estimating requirements are easily evaluated. OVERALL GROWTH FACTORS Table I gives the population, retail sales, and value added by manufactures in the U. S. and in the eleven western states in 1954. These data are rough guides to the proportionate part of total U. S. markets for products containing mineral fillers that may be expected in a given area. For example, the population of the eight Mountain states in 1954 was 3.6 pct, and retail sales in these states were 3.8 pct of the U. S. total, but the value added by manufactures was only 1.3 pct of the U. S. total. On the other hand, the three Pacific Coast states, with 10.3 pct of the total population, had 12.0 pct of the retail sales and produced 9.6 pct of the value added by manufactures. On an industry-by-industry basis the correlation between the three guideposts will not be as close as shown in the 1954 data for the Pacific Coast states, but in the long-term view the continuing rapid population growth in the western states is certain to result in expanded industrial production at an even more accelerated pace, which will shorten the gap between local consumption and production in most major groups of manufactured consumer goods. Of course, there will always remain favorable areas for production of specific products. Such special situations must be individually analyzed. Fig. 1 compares the population trends in the U. S., the western states, and California with Real Gross National Product from 1910 to 1957, with forecasts to 1970. It is estimated' that the U. S. Real Gross National Product, as measured by the value of goods and

Jan 1, 1960

By N. Lilienberg

Refractory materials play much the same part in the producion of metals as houses and shelter for men, and it therefore seems useful to discuss sometimes the ways of manufacturing them. In fact, it appears to me that too little has been said on this important matter, probably because the manufacturers of fire-brick do not care to publish details for the benefit of competitors, but perhaps, also, by reason of the indulgent indifference of consumers. Judging from the revolutions in the manafacture of iron and steel caused by using calcareous materials for the furnace-bottoms, it does not seem improbable that in the future basic bricks may be produced suffciently strong for building also side-walls and arches, and perhaps, also, for use in blast-furnaces. But the existence of the present difficulties of great shrinkage in burning and small strength against compression, which limit the possibility of using basic bricks to Bessemer converters and such open-hearth furnaces as permit the bottom to be separated from the superstructure, seems to indicate still a long and extensive use of silica fire-bricks. I am not prepared to say anything about American fire-brick making, but knowing that industries abroad are watched with increasing interest by American manufacturers, I have imagined that this association would like to hear some facts about the way firebricks arc made in my country—Sweden. Well-known as it is that Sweden produces a high quality of iron, it is perhaps not so universally known that the same country produces a very high grade of silica fire-brick, whereby most of its own wants are supplied. In giving the following sketch I can, of course, not claim that all the facts are entirely new, but shall consider my object attained if American manufacturers can derive some benefit from the comparison of the following methods with their own, and if some discussion on this important subject can be aroused which will contribute to further progress. In order to show the extensive use of domestic fire-bricks in Sweden, where English bricks are easily obtainable, I mention the fact that about twelve millions of all kinds of fire-bricks (reduced to

Jan 1, 1885

By E. C. Wright

FOR many years the cost of making pig iron and steel in the Birmingham district has been about the lowest in the United States. The close proximity of the important raw materials such as coal, iron ore, limestone, and the large available scrap supply made it possible to assemble all of the important ingredients necessary for steel-making with only nominal costs for transportation. Both iron ore and coal were being mined in this district at one time for about $1 per ton from underground operations. At that time mining wages were low everywhere and the labor rate in the South was considerably below that of other mining districts. This situation persisted until the emergence of labor unions as an economic and political force, emigation of southern labor to northern plants, and continued growth of industry in the South in the years following the depression of 1932. Since that time union organizing of miners and steel workers throughout the nation has increased labor costs in mining and steelmaking. This influence has been felt particularly in underground mining operations since the proportion of labor cost to total cost is still high. The previous advantage in basic labor rate in the South has been almost entirely eliminated by the equalization of labor rates in basic industries by national unions.

Jan 12, 1950