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By Milton Fies

ALTHOUGH pig iron from iron ore and red cedar charcoal preceded the mining of coal by many years, for tradition says that Alabama iron was used to shoe the horses of Andrew Jackson's soldiers, coal was not produced until 1830. In that year, coal was mined in Tuscaloosa County, in the vicinity of what is now the University of Alabama, and shipped on flat boats (obviously during the wet season, for there were many shoals) down the Warrior River to Mobile. About that time, the first railroad, the Decatur & Tecumseh, was being constructed in northern Alabama to overcome the obstructions to freight traffic caused by the now well-known Muscle Shoals in the Tennessee River. This railroad was patterned after a railroad at Mauch Chunk, Pa., which was used for hauling anthracite from the Panther Creek valley. The Alabama railroad, which required about four years to complete, was 46 miles long and was used solely for the transportation of cotton. Although it was a failure, it demonstrated the practicability of the undertaking, and the succeeding railroads, which were begun in 1834, 1848, 1852, and 1853, added immeasurably to the development of the coal resources of the state. Between the years 1830 and 1860, practically all the coal mined in the state was dug from the outcrop near the river or from the river beds, and shipped by boat to Mobile. Transporting coal down the Warrior River was one of great risk, required much skill, and frequently had heavy losses. It is recorded that this coal was sold to the gas company in Mobile in 1844; it was most likely mined from the Black Creek Seam. In 1914, on the completion of Lock 17, the Warrior River became a navigable stream from 9 miles above Cordova, Ala., to Mobile and offers a great opportunity for the future development of the coal resources of the state.

Jan 9, 1924

By J. E. Spurr

Jan 1, 1903

By Waldemar Lindgren

No one would maintain that all ore deposits or all deposits of useful minerals have been formed by the same processes. Generally they have originated by special processes of concentration but these may be of many different kinds. Some deposits have their origin in chemical or biochemical processes of concentration in rivers, lakes or seas, others, developed on land by, means of chemical reactions of surface waters on various forms of rocks. Certain insoluble substances remained behind; others were dissolved and precipitated in favorable places. This action -proceeded in the realm of the oxidizing surface waters or in the deeper zones to which the waters from the surface could find their way. Examples of the latter kind may be found in the extensive copper and vanadium deposits of some sedimentary beds or in the lead and zinc deposits of certain broad limestone strata. In these instances the evidence for any other mode of origin would seem to be very weak indeed.1 Nor does it seem possible to deny that circulating waters may form deposits of the more common metals along fissures after having dissolved many constituents from paths traversed. Another very large class has been formed by magnetic processes of concentration. The last 40 years have been a period of intense activity in. the investigation and description of a vast number of deposits; all modern methods have been employed and the result is an accumulation of data, difficult or impossible to master. It has been a period similar to that in petrography. The generalizations, the able deductions have lagged behind. Evidently several geologists have become weary of this "infinite detail" and a mistrust of the microscope seems to have. arisen. Although this feeling of being swamped in microscopic detail is a painful experience, nevertheless only through the detail in combination with

Jan 6, 1926

By AIME AIME

THE No. 9 mine of the Wheeling & Lake Erie Coal Mining Co., a subsidiary of M. A. Hanna & Co., at Fairpoint, Ohio, has normally produced about 1000 tons of coal daily for several years, but recently it was converted into an experimental mine to afford means of studying new methods and equipment under consideration for development and mining. Among other projects, the possibility of using a duck-bill, self- loading conveyor in driving entries, with a view of in- creasing the rate of progress where quick development is of importance was studied. Actual operation soon revealed that even though break-throughs are made ,every 60 ft., as required by the state mining laws, the :amount of natural Ventilation reaching the working face was not sufficient to supply the men and that in ,order to obtain a plentiful supply of pure. air and maximum efficiency and to avoid costly interruptions after shots, it was necessary to supply auxiliary ventilation by using Ventube and a Vano fan.

Jan 1, 1929

By D. B. Hobbs, L. W. Kempf, R. S. Archer

SILICON is one of the most important elements in the metallurgy of aluminum. It is always present in small amounts in the ordinary grades of "pure" aluminum, and hence in all alloys made therefrom. Within the last few years binary alloys containing up to 13 per cent. of silicon have come into extensive use for castings. Silicon is also added, beyond the amount present as an impurity, in alloys containing one or more other elements such as copper, manganese, magnesium and nickel. The binary aluminum-silicon alloys are not yet heat treated to any extent in commercial practice, although, as will be shown, their properties are affected to a very considerable degree by heat treatment. There are other aluminum alloys that develop higher strength, but the special characteristics of the silicon alloys may well lead to the application of heat-treating processes on a commercial scale. The role of silicon in the heat treatment of aluminum alloys is more important than would be indicated by consideration of the binary alloys alone, because many of the alloys that are heat treated in regular commercial practice contain some silicon in addition to that derived from the aluminum ingot as an impurity. Among these may be mentioned the heat-treated 195 alloy castings, and the wrought alloys 25S, Special 17S and 51S of the Aluminum Co. of America, and the German wrought alloy, Lautal. It is the purpose of this paper to present the results of experimental work and the conclusions derived therefrom regarding the heat treatment of the binary aluminum-silicon alloys. The products heat treated included forgings, chill castings and both "normal" and "modified" sand castings. REVIEW OF LITERATURE The literature on the heat treatment of aluminum-silicon alloys is not very extensive. The following review gives the principal references of which the authors are aware, in which appreciable information may be found.

Jan 1, 1928

By Arthur C. Spencer

IN extension of a suggestion already made to account for certain features observed in the Juneau gold-belt in southeastern Alaska,' it is the object of the present paper to indicate in detail certain conditions in which deformation of rocks under their own weight might lead to the production of fractures in which veins could be deposited. A direct, uniformly-distributed pressure of sufficient intensity applied to an elastic brittle mass offering strong resistance to deformation produces rupture. In a material of ideal properties the surfaces of rupture under such pressure would be shearing planes inclined at 45° to the line of force, unless there be preliminary deformation, in which case this angle would be greater than 45°. This general conclusion, resting upon ana¬lytical mechanics, is completely supported by the results obtained by Daubrée in experiments upon the deformation of wax and resin prisms under compression. Let us then first con¬sider one of Daubrée's diagrams. In the case illustrated in Fig. 1, four sets of fractures in two appproximately right-angled pairs (that is to say, in conjugate sets) were produced by end-wise compression of the square cross-sectioned prisms. These fractures cut the axis of compression at approximately equal angles, not varying greatly from 45°. The location of the four sets of fractures is obviously determined by the shape of the prism, since the material in each corner acts in a way as a buttress, permitting the bulging to take place most readily on the sides. By limiting the directions in which bulging may take place, results of a more simple nature could be obtained. Take, for instance, a square prism and place it between two fixed and

Nov 1, 1905

By AIME AIME

S ULFURIC acid made in the United States during the last four years has averaged approximately 7,000,000 tons of 50" B6 acid a year. This is double the production of the year 1913. About 66 per cent of the acid is made from sulfur, 16 per cent from pyrite, 13 per cent at copper, lead, and zinc smelters, and the remainder from miscellaneous sources it her the chamber process or the contact process, (at some plants both) is used. In 1923, the contact process accounted for nearly 30 per cent of all the sulfuric acid made in this country and since then it has been increasingly employed. It was first introduced here in 1898, and has always .proved less expensive than the chamber process for the manufacture of .acid of high concentration and purity, but the latter produces acid of low strength suitable for many industries.

Jan 1, 1929

By W. H. Triplett

DISCUSSION John G. Barry (Mexico)—"The Nerinea limestone," writes W. H. Triplett, p. 584, "is ... medium-bedded (0.5 to 1.0 m)...." This is the Zuloaga formation. It has always been described as thick-bedded (1.0 to 3.0 m). "Whether the marls and shales were less amenable to replacement," he goes on to say, ". . . is a matter of opinion." In general, it is probable that the thinner-bedded formations were less competent than the nearby thicker-bedded, so that the latter produced pre-mineral breccias when all were subjected to flexing stresses. With reference to Mr. Triplett's analysis, p. 584, under Lower Cretaceous, in the Taraises and Cupido formations some few horizons should be considered as possibly containing hidden orebodies. In the Potrero camp, shown on the general map in the northwestern part of Fig. 4, p. 587, several mineralized beds are known; they are found throughout the whole thickness of the Cuesta del Cura formation. With regard to intrusive rocks, p. 585, the general map, Fig. 4, shows that the Potrero and Noche Buena camps are near a third, monzonitic intrusive. It seems doubtful that the Aranzazu was any hotter than the Providencia camp. However, the former does contain large deposits of exogenetic silicates, which in large part occur within the Zuloaga limestone, as shown by Bergeats in a stereogram. At the Aranzazti camp the La Caja formation was only slightly changed, whereas it was altered highly at the Providencia, possibly en-dogenetically. That the temperatures at the Providencia camp were relatively high at one time is also shown by the tourmaline veinlets and lenses in the monzonite and by the garnets on Temeroso peak; high temperature mineralization has possibly been eroded. Maps and sections show that the Concepcion del Oro —Temeroso stock occupies the original locus of some 40 kms of sedimentary rocks. The remains of large roof pendants at Carmen and Animas indicate that stoping was active. Whether all the sedimentaries were stoped and assimilated presents a lively problem, a correlative of which would be an estimate of the original constitution of the invading instrusive rock. As to extrusive rocks, see p. 585, there is also a large thick area of the extrusives left near Noche Buena in the "La Caja" intramontane valley of the La Caja range. This place gave its name to the range. The volcanics are also said to occur in considerable amount in the Mazapil valley.'' Turning now to the remarks under Regional Structure, p. 586, as partly indicated on the general map, Fig. 4, the Mazapil Mountains of the Mazapil region are a continuous, U-shaped range including a northern leg of some 24 km, a southern leg of similar length, and a uniting base which lies to the East and which measures some 10 km in a S 20 E direction. Thus the U-shaped mountains are continuous through a length of 58 km and also contain one continuous anticline, the adjacent valleys being synclinal. The northern leg of the U is called the La Caja range, the base is called the Concepcion del Oro range, and the southern leg the Santa Rosa range. The ranges in northeastern Zacatecas and southern Coahuila contain anticlines and the valleys contain synclines, which where thin are necessarily highly compressed isoclines with very steep dips. Many of the anticlines also have isoclinal components which are overturned, original mushroom tops being indicated. The anticline in the base of the U of the Mazapil Region, Concepcion del Oro range, is a recumbent anticline, over to the ENE, with a necessarily subjacent recumbent syncline.

Jan 1, 1953

By W. H. Triplett

DISCUSSION John G. Barry (Mexico)—"The Nerinea limestone," writes W. H. Triplett, p. 584, "is ... medium-bedded (0.5 to 1.0 m)...." This is the Zuloaga formation. It has always been described as thick-bedded (1.0 to 3.0 m). "Whether the marls and shales were less amenable to replacement," he goes on to say, ". . . is a matter of opinion." In general, it is probable that the thinner-bedded formations were less competent than the nearby thicker-bedded, so that the latter produced pre-mineral breccias when all were subjected to flexing stresses. With reference to Mr. Triplett's analysis, p. 584, under Lower Cretaceous, in the Taraises and Cupido formations some few horizons should be considered as possibly containing hidden orebodies. In the Potrero camp, shown on the general map in the northwestern part of Fig. 4, p. 587, several mineralized beds are known; they are found throughout the whole thickness of the Cuesta del Cura formation. With regard to intrusive rocks, p. 585, the general map, Fig. 4, shows that the Potrero and Noche Buena camps are near a third, monzonitic intrusive. It seems doubtful that the Aranzazu was any hotter than the Providencia camp. However, the former does contain large deposits of exogenetic silicates, which in large part occur within the Zuloaga limestone, as shown by Bergeats in a stereogram. At the Aranzazti camp the La Caja formation was only slightly changed, whereas it was altered highly at the Providencia, possibly en-dogenetically. That the temperatures at the Providencia camp were relatively high at one time is also shown by the tourmaline veinlets and lenses in the monzonite and by the garnets on Temeroso peak; high temperature mineralization has possibly been eroded. Maps and sections show that the Concepcion del Oro —Temeroso stock occupies the original locus of some 40 kms of sedimentary rocks. The remains of large roof pendants at Carmen and Animas indicate that stoping was active. Whether all the sedimentaries were stoped and assimilated presents a lively problem, a correlative of which would be an estimate of the original constitution of the invading instrusive rock. As to extrusive rocks, see p. 585, there is also a large thick area of the extrusives left near Noche Buena in the "La Caja" intramontane valley of the La Caja range. This place gave its name to the range. The volcanics are also said to occur in considerable amount in the Mazapil valley.'' Turning now to the remarks under Regional Structure, p. 586, as partly indicated on the general map, Fig. 4, the Mazapil Mountains of the Mazapil region are a continuous, U-shaped range including a northern leg of some 24 km, a southern leg of similar length, and a uniting base which lies to the East and which measures some 10 km in a S 20 E direction. Thus the U-shaped mountains are continuous through a length of 58 km and also contain one continuous anticline, the adjacent valleys being synclinal. The northern leg of the U is called the La Caja range, the base is called the Concepcion del Oro range, and the southern leg the Santa Rosa range. The ranges in northeastern Zacatecas and southern Coahuila contain anticlines and the valleys contain synclines, which where thin are necessarily highly compressed isoclines with very steep dips. Many of the anticlines also have isoclinal components which are overturned, original mushroom tops being indicated. The anticline in the base of the U of the Mazapil Region, Concepcion del Oro range, is a recumbent anticline, over to the ENE, with a necessarily subjacent recumbent syncline.

Jan 1, 1953

By Victor O. Homerberg, Dexter N. Shaw

A study of the correlation of the mechanical properties and of the microstructure with the heat treatment of 60-40 brass has been confined, heretofore, to the rolled or extruded material as received from the mannfacturer. The results obtained by Babson and Buhler,' Bengough and Hudson12 Stead and Stedman,3 and Brayton4 have been confined to the treatment of the material as received. No attempt was made to get the material into a given condition and then to work from this basis. To start with a given structure would have the decided advantage of making the work independent of the original condition, hence, to make the results reproduceable. In a previous paper, it was shown, in connection with the study of the transformation that occurs at about 470" C., that if specimens were quenched to produce the beta structure and then reheated, the beta would begin to break down, at approximately 200" C., into a very finely divided alpha. It was predicted that important results might be obtained if test pieces were to be given a similar double heat treatment and then tested for the mechanical properties as well as a study of the microstructure. The material used in the present investigation was a 3/4-in. round bar of extruded muntz metal of the following composition: Copper, 61.05 per cent.; zinc (by difference), 38.90 per cent.; lead, 0.05 per cent.; iron, trace; tin, nil.

Jan 1, 1924

By B. C. Woodfine

WHEREAS it is generally assumed that the highest temperature at which temper brittle-ness takes place is about 625°C, 1,2,3 Jaffe, Buffum, and coworkers have referred in several recent papers45,6,7 to the occurrence of temper brittleness in an SAE 3140 steel at 650" and 675°C. Their re- sults show that a considerable increase in transition

Jan 1, 1955

By Gary E. Melickian

Last year's review was characterized as a year of politics and began an era of legislation. The 1972 review can be similarly characterized, with even more rigid health and safety regulations and environmental legislation. The mining industry should be aware of what's happening in the nuclear power and other fields as a result of the National Environmental Policy Act (NEPA) of 1969, where the environmental impact of most major construction activities are already under close scrutiny. Section 102 of NEPA requires that all federal agencies include a detailed statement on specified environmental conditions as part of every report on proposed actions significantly affecting the quality of the human environment. All such environmental reports must consider the same general conditions: • The environmental impact of the proposed action. • Any adverse environmental effects which cannot be avoided should the proposal be implemented. • Alternatives to the proposed action. • The relationship between local short-term uses of man's environment and the maintenance and enhancement of long-term productivity. • Any irreversible and irretrievable commitments of resources which would be involved in the proposed action should it be implemented.

Jan 2, 1973

By J. J. Forbes

'"THE Federal Coal Mine Safety Act (public Law T. 552. 82nd Congress) was approved oil July 16, 1952. It incorporates, as Title I, the Coal Mine Inspectio1.1 and Investigation Act of May 7. 1941 (Public Law 49, 77th Congress), which gave Federal inspectors only the right to enter. coal mines for inspection and investigation purposes but no power to require compliance with their recommendations. Title 11 contains the enforcement provisions of the act; its purpose is to prevent major disasters in coal mines from explosions, fires. inundations. and man-trip 01. man-hoist accidents. At this point a brief account of events that preceded the enactment of the Federal Coal Mine Safety Act seems appropriate. The hazardous nature of coal mining was recognized by the Federal Govermment as long ago as 1865, when a bill to create a Federal Mining Bureau was introduced in Congress. Little was done, however, until a series of appalling coalmine disasters during the first decade of this century provoked a demand for Federal action. As a result an act of Congress established a Bureau of Mines in the Department of the Interior on July 1, 1910. The act made it clear that one of the foremost activities of the Bureau should be to improve health and safety in the mineral industries. One of the first projects selected by the small folce of engineers and technicians then employed was to determine the causes of coal-mine explosions and the means to prevent them. By investigations aftel mine disasters the fundamental causes and means of prevention were soon discovered, and the coal mining industry was informed accordingly. However, despite this knowledge and the enactment of State laws and the Federal Coal Mine Inspection and Investigation Act of 1941, mine disasters continued to occur with disheartening frequency and staggering loss of life. The devastating explosion at the Orient No. 2 mine on December 21, 1951, resulted in the death of 119 men. The Orient disaster rekindled the memory of the Centralia. Ill., disaster of March 25. 1947, which caused the death of 111 coal miners. These two tragedies ultimately brought about enactment of the Federal Coal Mine Safety Act. The act is a compromise measure. Senator Matthew M. Neely of West Virginia and Congressman Melvin Priec of Illinois introduced almost identical versions in the 82nd Congress, but they were considered too drastic. The final version was introduced by Congressman Samuel K. McConnel, Jr., of Pennsylvania, after considerable discussion and amendment in committee hearings. It was passed by the Congress and became effective when signed by the President on July 16, 1952. The act is somewhat limited in scope because it applies only to approximately 2000 coal mines in the United States and Alaska that employ regularly 15 or more individuals underground. It exempts approximately 5300 mines employing regularly fewer than 15 individuals underground and all strip mines, of which there are about 800. Moreover, it covers only conditions and practices that may lead to major disasters from explosion, fire, inundation, or man-trip or man-hoist accidents. According to Bureau records, such accidents have resulted in less than 10 pct of all the fatalities in coal mines. It is important to mention that the law is not designed to prevent the day-to-day type of accidents that have caused the remaining 90 pct or more of the fatalities, because it was the specific intention of the Congress to reserve the hazards which caused them to the jurisdiction of the coal-producing states. Many who opposed any Federal legislation that would give the Federal inspectors authority to require compliance with mine safety regulations claimed that such legislation would usurp or infringe upon States' rights. To assure that the principle of States' rights would be preserved, the act provides for joint Federal-State inspections when a state desires to cooperate in such activities. The Director of the Bureau of Mines is required by the act to cooperate with the official mine-inspection or safety agencies of the coal-producing states. The act provides further that any state desiring to cooperate in making joint inspections may submit a State plan for carrying out the purposes of this part of the act. Certain requirements are listed: these must be met by a state before the plan can be accepted. The Director of the Bureau of Mines, however, is required to approve any State plan which complies with the specified provisions. The Director may withdraw his approval and declare such a plan inoperative if he finds that the State agency is not complying with the spirit and intent of any provision of the State plan. When this paper was prepared, agreements for joint Federal-State inspections had been entered into with Wyoming and Washington. A few other states have indicated their desire to submit a State plan and negotiations toward that end are now under way. Reluctance to enter into such agreements may be due to the mine operators' knowledge that in the states that adopt a cooperative plan they are prohibited from applying to the Director of the Bureau of Mines for annulment or revision of an order issued by a Federal inspector and must appeal directly to the Federal Coal Mine Safety Board of Review for such action. Experience has proved that review by the Director as provided in the act is a less expensive and time-consuming procedure to all concerned than applying to the Board. Reluctance also may stem from the fact that joint Federal-State inspections somewhat restrict the movements of the State mine inspectors and tend to reduce the number of inspections of mines. Where a State plan is not adopted, the Federal coal mine inspector is responsible under the law to take one of two courses of action if he finds certain hazardous conditions during his inspections. The first action involves imminent danger. If a Federal inspector finds danger that a mine explosion, mine fire, mine inundation, or man-trip or man-hoist accident will occur in a mine immediately or before the imminence of such danger can be elim-

Jan 1, 1955

Jan 1, 1889

By H. H. Uhlig

Soon after general use of stainless steels began, it was observed in practice that certain combinations of factors tended to induce corrosion by pitting. For most applications this was a serious drawback, not so much because the structural properties of the metal were impaired but because of the rapidity with which heavy sections of the alloys were penetrated by small elongated pits. These pits seemed to initiate readily in oxidizing metal salt solutions like ferric chloride and in chloride solu-tions like sea water. It was observed that in sea water pitting was more frequent in stagnant or polluted waters than in highly aerated, moving waters. The steels in these chloride solutions were observed to be sensi-tive to long contact with material such as sand grains or attached bar-nacles. At points of attachment or contact it was not uncommon to discover initiation of corrosion. Pits once begun at contact faces were observed to grow rapidly, usually elongating phenomenally in the direc-tion of gravity until the metal was perforated. Hydrochloric acid and other nonoxidizing acids, on the other hand, were observed to corrode stainless steels generally; the weight losses often were higher, but the penetration less than for the pitting type of corrosion. The causes of pitting, a type of corrosion recognized as character-istic not only of stainless steels but of many additional metals and alloys, are important in corrosion studies. A possible explanation bears prac-tical significance, for once it is known why pits begin where they do and continue to grow after initiation, intelligent direction can be given to diminishing corrosion. This can be done either by some alteration in the composition and treatment of the alloy or by some alteration in the environment. It appears foremost in importance to discover the nature of pit foci, for if initiation of pits can be discouraged their growth will be no longer a factor to be considered. In a multi-component alloy containing many impurities normal to production of such an alloy, each of which may play a part in pitting, and whose corrosion resistance is sensitive to heat-

Jan 1, 1940

By M. R. Tek, M. L. Katz

The flow of fluids in stratified porous systems, in which adjacent layers of the system are in communication over part or all of their common interface, in many instances involves crossflow between layers. A theoretical study has been made of the unsteady-state flow of slightly compressible fluids during depletion of bounded stratified porous systems. Consideration has been restricted to single-phase flow, with negligible capillary and gravity effects. Analytical expressions have been derived for pressure distribution and for (luxes at the producing face in two-layer systems with complete fluid communication between layers. These expressions occur in the form of double Fourier and Fourier-Bessel series. The method of extending the solution to any number of layers is demonstrated by deriving the equation for pressure distribution in a three-layer system. On the basis of the exact results for two-layer systems, certain generalizations regarding the behavior of stratified systems in general are presented. The performance of stratified systems, in terms of cumulative flux as a function of time, is shown to lie at all times between bounds established from single-layer theory. The upper bound is given by treating the system as a single layer with arithmetic average physical properties. The corresponding lower bound is the summation of the fluxes from each layer as treated individually. Variation in performance of stratified systems between the upper and lower bounds is determined by the extent to which crossflow occurs in the system. The principal parameters affecting the amount of crossflow are the vertical permeability of the system, the ratio of system thickness to "radius of drainage" and, for radial systems, the ratio of system thickness to interior radius. At very early times, the system performance is near the lower bound. As time and the radius of drainage increase, the per- formance tends toward the upper bound. INTRODUCTION One of the principal problems confronting the reservoir engineer today is the incorporation of the effect of reservoir heterogeneity into predictions of reservoir performance. The first part of this problem is the characterization of the actual reservoir heterogeneity in a mathematically useful manner.1, 2 It is then necessary to calculate the effect of this heterogeneity on the system performance. It is frequently possible to estimate this effect by comparison with the known behavior of an idealized system. One such idealized system is the stratified or "layer-cake" model. Many studies have been made of the behavior of stratified systems, from both a theoretical and experimental standpoint. The great majority of the theoretical studies have been concerned with systems of separated layers, with no fluid crossflow. Among the more noteworthy of such theoretical papers is that recently published by Lefkovits, et al,3 in which a comprehensive analysis was presented for the behavior of bounded stratified systems which are unconnected except at the wellbore. Three recent references have dealt with stratified systems including the effect of crossflow. Jacquard4 has presented mathematical derivations pertaining to depletion of two layer systems producing at constant rate. A doctoral dissertation by Katz5 contains analytical solutions and tables of results for pressure distribution and fluid flux during constant-terminal-pressure depletion of two-layer and three-layer systems with crossflow, together with tables of eigenvalues necessary in the computations. The dissertation also presents results from experimental studies of stratified systems using a heat-transfer analog model. This paper is largely based on the material in this dissertation. A third paper has been presented by Russell and Prats6 since completion of the work resented herein, containing mathematical derivations for and discussion of the behavior

KNOWING the endpoint, or the equilibrium state, in steelmaking reactions is only part of the story. The rate at which the reactions proceed can be equally important. But the power of thermodynamics, which enables us to estimate the endpoint, is that a knowledge of the mechanism is not required. The methods of kinetics, however, are step-by-step analysis in which a knowledge of the detailed reaction mechanism is essential. As is evident from Chapter 16, a great deal of thermo- dynamic data for steelmaking are available and the underlying theory rests on a completely sound basis. This is far from the case with kinetic data and even kinetic theory. Nevertheless, it is worthwhile to examine the present state of knowledge, to see how far it may be applied to electric furnace reactions. KINETIC THEORY Heterogeneous Reactions. Classical kinetic theory and experimentation have been mainly concerned with homogeneous reactions taking place between different chemical species in a gas or liquid phase. The species are mixed together and the progress of the reaction can then be observed. This is possible because most experiments have been done at relatively low temperatures where the characteristic time for the mixing process is much shorter than the time for the chemical reaction to be completed. For example, in the homogeneous gas reaction, H2 (g) + I2 (g) 2HI (g) hydrogen and iodine may be added to opposite ends of a tube containing a diaphragm. When this is withdrawn, gaseous diffusion (and convection) mixes the two types of molecule almost completely before any hydrogen iodide molecules begin to appear. Such an experiment is inconceivable at more elevated temperatures, since the rate of the chemical process is so sensitive to temperature that reaction would be completed almost instantaneously wherever hydrogen and iodine came into contact; the rate of the mixing process would then determine the rate at which hydrogen iodide was formed. We should not, therefore, expect to observe many homogeneous reac-

Jan 1, 1964

By M. Sagheer

This paper gives a report of the laboratory work investigating the fundamental flotation characteristics of chromite and its commonly associated mineral, serpentine. Floatability curves, showing floatability of chromite at different concentrations of sodium oleate and pH, were obtained by pick-up method. One of the difficulties encountered in flotation of chromite in presence of serpentine has been attributed to dissolved metal ions. The influence of metal ions, dissolved in pulp filtrate, on floatability of pure chromite and serpentine has been studied and it has been shown that Mg, Ca and Fe ions depress chromite. A considerable amount of work applying bubble pick-up method was carried out to counteract the depressing action of metal ions. Various methods and reagents were applied in this connection. Validity of each method and reagent has been discussed. Probably due to the abundance of high-grade chrome ores, very little has been published concerning the flotation of chromite. As improvements in mineral beneficiation are realized, more attention is being directed to low-grade ores previously considered unusable. Currently, gravity concentration is the principal process applied to upgrade chrome ores, but this cannot be used for finely disseminated ore because of the substantial losses in the fines,1,2,3 To avoid these losses, flotation can be applied to material which is too fine for satisfactory gravity concent ration, and it is probable that a combination

Jan 1, 1967

APPROXIMATELY 90 per cent of the steel that is melted and refined in the United States and poured into ingots is made in basic open-hearth furnaces, as shown in Table 1-1. The annual ingot capacity of the steel industry reported January 1, 1950, by the American Iron and Steel Institute3* was 99,040,160 tons, of which the basic open-hearth process accounted for 85,896,580 tons, 86.7 per cent of the .total. The capacity of the individual furnaces varies over a wide range, a large majority falling within limits of 50 to 200 tons (Fig 1-1). Most of the units constructed [ ] since 1942 are in the larger size groups, between 175 and 225 tons capacity.

Jan 1, 1964

By Robert Lewis

THE Utah coal field to which the name Book Cliffs is applied runs in a northeast direction from Mt. Hilgarde, in Sevier county, along the escarpment of the Wasatch Plateau to the vicinity of Castle Gate, thence southeast along the Book cliffs, which lie to the north of and generally within sight of the Denver & Rio Grande Railroad,. to the Colorado line. The Book cliffs form the southern escarpment of the West and East Travaputs Plateaus, and vary in height from 2,000 to 6,000 ft. At the base of the Wasatch and Book Cliffs escarpments is a broad plain known as Castle valley. The coal beds outcropping in the escarpments along this valley are worked on the largest scale of any in the State, and this particular area is known locally as the Castle Valley coal field. Geology The Book cliffs are capped by the Tertiary-Eocene-formation, consisting of varicolored shales; buff sandstone, conglomerate, and subordinate thin beds of limestone. Different sections show diverse stratigraphy. This is mainly the Wasatch formation, and lies unconformably upon the rocks of the Upper Cretaceous. Fig. 1 is a generalized section of the rocks of the. Book Cliffs field. The Mesaverde formation contains the cliff-making rocks of the Book cliffs, and is composed of massive sandstone interbedded with sandy shales and beds of coal and carbonaceous shale. The sandstone has greater resistance to erosion and the formation is characterized by escarpment ledges and cliffs. The shale is commonly sandy and is drab in color, but where it is associated with the coal it is usually carbonaceous. The sandstone is generally buff, though occasionally it is white, and in places red. The bedding ranges from thin to massive. In the lower part. of the formation the sandstone is red in

Jan 7, 1914