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By W. D. Steele, S. D. Brady

The Pittsburgh coal seam in West Virginia contains the largest coal reserves of any coal seam in that State and is, therefore, one of the most important seams, and attains minable thickness and purity throughout that part of the seam extending from the Northern Panhandle to Monon-galia Co. thence south and southwest across the state to Wayne Co. near Hunt-ington. The Pittsburgh coal is also minable in the Upper Potomac region but is now practically exhausted there. The total minable areas of this coal amount to 2,165 sq miles and are estimated, by the West Virginia Geological Survey, to contain 13¼ billion net tons. The largest body of Pittsburgh coal outcrops on the western edge of West Virginia, along the Ohio River as far south as Moundsville, West Va., going under the river at that point and extending at various depths down the river as far as Wetzel Co. line where it thins out to such an extent that it has little practical value, and on the eastern edge this large body outcrops along the Monongahela River. The territory to be covered by this paper is the area known as the Northern West Virginia District comprising Wetzel, Mon-ongalia, Marion, Preston, Harrison, Dodd-ridge, Taylor, Barbour, Upshur, Lewis, Gilmer, Braxton and Calhoun Counties, and is also known as Dist. 3 under the Bituminous Coal Act. This region was originally opened for commercial mining along and adjacent to the Monongahela River around 1852 when the Baltimore and Ohio Railroad was constructed to Fairmont. It has been extensively developed, first, in 1880 (when the Monongahela River Railroad, now B. & 0. R. R., was constructed) between Fairmont and Clarksburg, and later, in 1916, between Morgan-town and Fairmont when the Monongahela Railway was constructed and placed in operation, this area furnishing the major portion of the production over the past years. With the mining out of a great deal of this territory adjacent to the Mononga-hela River considerable interest has been developed in the back acreage; and within the past few years a number of diamond core drill holes have been made in the back areas of Monongalia and Marion Counties. In this back area the oil and gas well drilling showed that the Pittsburgh coal seam was of minable thickness and ranged in depth from 350 to 1,000 ft below the surface of the stream valleys but this drilling did not furnish any definite data as to its thickness and quality. Economic Importance The Pittsburgh seam in Northern West Virginia is of primary importance as a coal resource not only because of its large reserves but because of its contributing a very large part of the coal used in this country for general steam uses. The Pittsburgh seam is a consistently thick seam, averaging 8 ft in thickness, with very easy grades underground, so it has always been

Jan 1, 1949

By H. T. Green, R. M. Brick

True stress-strain data on alloys of pure iron with up to 2.4 pct Al were obtained in the temperature range +100° to —185°C. Alumi-num was found to reduce yield and flow stresses of iron at low temperatures but to have little or no effect on ductility. The effects of temperature and composition on strain hardening are discussed. SEVERAL independent studies of the behavior of high purity iron binary alloys at low temperatures are now in progress in attempts to evaluate systematically the variables affecting the low temperature brittleness of ferritic steels. This paper reports the results of one such investigation in which the tensile properties of aluminum and aluminum plus silicon ferrites were measured from 100" to —192°C. True stress-natural strain data have been obtained in order to evaluate as many as possible of the parameters which describe the behavior of the materials involved. In comparable studies at the National Physical Laboratory in England, iron and iron alloys of high purity have been produced' and tested at subat-mospheric temperatures.' True stress-natural strain curves were obtained there also. The purest iron contained 0.0025 pct C and 0.001 pct O and N. Even this, as normalized at 950°C following hot rolling, showed little ductility at -196°C. The grain size was ASTM No. 3, and the room-temperature yield strength was 17,800 psi (which seems too high for pure iron). Some of the NPL irons contained considerably more oxygen and demonstrated intergran-ular fracture at —196°C. The authors2 carefully differentiated between intergranular fractures associated with excessive oxygen content and transcrys-talline cleavage with little ductility encountered at —196°C in the purer material. The cleavage stress was half again as great as that associated with inter-granular fracture. Test Material, Preparation, and Procedures Of a number of Fe-A1 alloys produced, eight were considered to be sufficiently pure for testing. Partial chemical analyses (Table I), low observed yield points, and high ductilities indicate these alloys to be comparatively pure for vacuum-melted irons of sizable ingots, 5 Ib or more. To produce the binary Fe-A1 alloys, electrolytic iron was melted in air, cast into slabs, and rolled to strips 0.010 in. thick. These strips, joined into a continuous ribbon and wound into 2 1/2 in. diameter spools, were subjected for four weeks to a moving atmosphere of purified dry hydrogen in a stainless-steel tube at 1050" to 1150°C. Charges of these spools were melted in beryllia crucibles under good vacuums (1 micron), and aluminum (99.97 pct Al) was added to the melts. Compositions of these alloys are recorded in Table I. The ingots were hot forged and then cold rolled at least 65 pct to 3/8 in. rods which were vacuum annealed to the desired grain size, approximately ASTM No. 4, prior to machining into tensile test bars. All tensile specimens had gage sections 1 in. long, with a fillet of 1.5 in. radius to the shoulder. Gage diameters were 0.250 in, except for a few rods where additional cold work required use of a 0.200 in. gage section. After machining, 0.002 in. was removed from the gage diameter using 240, 400, and 600-grit metallo-graphic papers. The final polish with 600 grit left the fine scratches running in the longitudinal direction. By this means, surface metal strained during machining was removed. A few specimens heat treated after machining were similarly reduced 0.004 in. to remove any material affected chemically by the atmosphere during heat treatments, as is discussed in a later section. Tensile tests of the eight alloys at constant temperatures from +100° to —185°C were performed in apparatus which has been described." The essentials include a double-walled insulated metal vessel which contained the liquid heat-transfer medium surrounding the test specimen. A constant temperature was maintained by means of a pyrometer which regulated the pressure of dry air driving liquid air through a copper coil. Temperature variation was less than ±2°C during a specific test. For axial straining, two lengths of case-hardened chain, terminating in simple shackles, loaded the specimen through threaded grips. The lower grip bar passed through a hole in the bottom of the test vessel to which it was joined by a thin-walled

Jan 1, 1955

By A. R. Troiano, E. A. Steigerwald, F. W. Schaller

D. N. Williams(BatteZle Memorial Institute)-The authors have presented an extensive collection of arguments pertaining to the role of stress in hydrogen embrittlement. The basic assumption of these arguments is that stress is essential as a driving force for diffusion of hydrogen. However, in view of the rapid diffusion rate of hydrogen in steel at low temperatures as evidenced by the ability to alloy with hydrogen by electrolytic charging, it seems unlikely to me that stress acts in this manner. Instead, I would like to suggest that stress may be essential for the nucleation of hydrogen in steel. I believe that such an assumption would equally well satisfy the experimental data presented by the authors. I should also like to comment on the interpretation of the data presented in Figs. 5 and 6. Fig. 5 shows the effect of hydrogen content on ductility in a rupture test. The curve as drawn by the authors indicates an abrupt transition from ductile to brittle behavior at about 0.001 amp per sq in. (5 ppm). The data points would equally well support a gradual transition from ductile to brittle behavior extending over the range from 0.0008 to 0.02 amp per sq in. (4 to 8 ppm). A gradual transition would be the ex-

Jan 1, 1962

By Wallace Pratt

INTRODUCTION IRON-ORE deposits in the Philippine Islands became the subject of official record as early as 1664. Undoubtedly iron ore was known and recognized by the Filipinos long before the earliest Spanish records. It is even possible that the Filipino practice of smelting iron ore is, like the native copper smelting, older than the Spanish conquest of the islands. The first records have to do with the magnetite-hematite ores near the towns of Santa Inez and Bosoboso in Rizal Province, from 15 to 20 miles east of Manila. The magnetite-hematite ores of Bulacan were exploited in 1783. Similar ores near the town of Mambulao in Camarines Province yielded a number of specimens to be exhibited in Spain in 1834. With the exception, then, of the lateritic iron ores on the eastern coast of northern Surigao, the true nature of which was not recognized until 1914, the important iron-ore deposits of the Philippines had all been discovered before the islands came under the dominion of the United States. Indeed, in the Spanish documents relating to the history of iron mining are statements which, if their accuracy be not questioned, leave us in the Philippines today with much less iron ore than the Spaniards found. To quote, for example, a report submitted to the Superior Government in Spain in 1835 by one of its emissaries, Don Lorenzo Calvo: "The Philippine Islands, most excellent Sir, possess iron and exhibit it in nearly every known mineralogical combination, and in such abundance that the cordillera of the island of Luzon, from Montufar Point in San Bernardino Straits to Cape Bojeador, is composed of no other mineral than iron, its ranges, of the third order, being in content and structure totally iron of the best quality, the more valuable in that its combinations are such as to facilitate its fusion and to render its reduction to metal simple."

Jan 2, 1916

By Harry A. Roe

THE power drag scrapers and the slackline cableway excavator have been called "long-range excavators." Broadly, their field of usefulness is restricted to work in which their long range of action permits them to operate economically, and which other, possibly more conventional, excavating units cannot do. Both of these machines dig or lift material and transport it to a remote dumping point. They combine these two functions in a single machine, nearly always in a single straight-line motion. [ ] The purpose of this paper is to examine the important features that distinguish the machines in this group from each other, as well as from other groups. The Machines The "power drag scraper" is a long-range excavating machine that employs a bottomless drag scraper operated back and forth between digging and dumping points by two haulage cables. The typical arrangement is that of Fig. 1. This is the "slusher" of the underground mine, as well as the "dragline scraper" of the sand and gravel industry, and other open-pit mining operations.

Jan 1, 1937

By W. A. Sweet

The furnace I am now about to describe was designed to obtain and maintain very high temperature. Knowing the cost of the gas furnace that was in successful operation here and abroad, I approached the subject with some misgivings as to my ability to attain anything like success, or even to reach a point of advancement. There seemed to be a field for a furnace of moderate cost for small mills, or where a particular heat was wanted, but the work was not enough to warrant the outlay necessary to build any gas furnace yet brought before the public. The section, Plate V, represents the furnace as I now build it for

By W. A. Sweet

THE furnace I am now about to describe was designed to obtain and maintain very high temperature. Knowing the cost of the gas furnace that was in successful operation here and abroad, I approached the subject with some misgivings as to my ability to attain anything like success, or even to reach a point of advancement. There seemed to be a field for a furnace of moderate cost for small mills, or where a particular heat was wanted, but the work was not enough to warrant the outlay necessary to build any gas furnace yet brought before the public. The section, Plate V, represents the furnace as I now build it for

Jan 1, 1875

By K. G. Davis

Dilute alloys of silzer in tilz haz been solidzjzed a1 controlled rules, in lzorizontal tubes 2 mrz and 0.5 rn in diam. Radioactive; tracer techniques we?-e used to study solute distvihutions along llze specimens and irmpurity substructures, as functions of the conditions growth. The results have heen mzalyzed using Burton, Prim, and Slichter's tnodel for the solute disty-ihution in the liquid ahead of an advancing solid-liquid interface. DECANTING techniques have been used to establish criteria for the formation of impurity substructure during solidification in several alloy systems An analysis equating the appearance of impurity substructure with the incidence of constitutional supercooling was developed,= in which diffusion was assumed to be the predominant mode of solute mixing in the liquid. Substitution of experimental data into the equations derived from the diffusion analysis gave reasonable values for solute diffusivity in the liquid. However, in these investigations solidification rates of 10 cm per hr and over were used, to minimize the effect of natural conection, whereas for crystals of high perfection lower solidification rates are needed, usually between 1 and 5 cm per hr. A knowledge of the conditions under which impurity substructures will be formed at low growth rates, and the degree of segregation to be expected, is therefore of interest. In the present investigation, radioactive-tracer techniques have been used to study the effect of growth rate, initial solute concentration, and size of specimen on the formation of substructure in uni- directionally solidified rods of dilute silver in tin alloys, over a range of growth rate between 0.5 and 10 cm per hr. Criteria for the formation of substructure were established by auto radiography. This was believed preferable to the decanting technique, for the relationship of the structure on a decanted interface with that of the freezing interface is not clear, since a layer of liquid is left on the surface following decanting.' The effect of substructure on the distribution of solute along the rods was also investigated. EXPERIMENTAL The procedure for sample preparation has been described in detail by einber. Alloys were prepared from tin of 99.999 pct purity and silver of 99.99 pct purity. A"', an emitter of both y and 0 radiation, was used as tracer. Samples of the alloys were drawn up into silica tubes with inside diameters 0.5 or 2 mm, remelted in a horizontal furnace, and solidified at controlled rates. A few centimeters of the samples were left unmelted for a measure of the initial concentration. Total sample length was approximately 20 cm. The temperature gradient in the furnace was kept constant at 36°C per cm in the region corresponding to the melting point for tin. To find how well this corresponded to the actual temperature gradient in the melt, a thermocouple of 38-gage wire was electrically insulated with a thin layer of Sauereisen cement and placed within one of the 2-mm-diam tubes, which was then filled with tin. The maximum diameter of the coated wire was 0.5 mm, the bead of the thermocouple junction being no larger than the diameter of the wire. A plot of temperature vs distance traveled by the furnace is given in Fig. 1 for a rate of furnace travel of 1 cm per hr. The temperature gradient in the liquid

Jan 1, 1967

By Francis A. Pocock

The writer is continually asked, if this electricity:is all you claim for it, why do not the mines put it in and use it? The best answer was given by Mr. John Fox Tallis, in his paper read before the South Wales Institute of Engineers in 1888, namely, that the reasons are similar to those which have prevented the more general employment of other systems of haulage. Managers, as a rule, are " not experienced mechanical engineers; neither are they all versed in electrical engineering." It may be said that there are a number of " able and practical electrical engineers who could do the work; but those electrical engineers are not conversant with the practical routine of colliery work and are, therefore, placed at a disadvantage by not knowing the actual requirements of mining engineers, and the many little difficulties to be met and contended with in underground workings; and, until mining engineers have acquired the necessary knowledge and a confidence in electricity, it is only natural that they will continue to follow the beaten path." In the above remarks, Mr. Tallis has hit the nail on the head. In the face of the partial failure, financially, of the haulage-plant which the Union Electric Company of Philadelphia had set to work at Lykens Valley, Pa., an electric haulage-plant was installed near Scranton, Pa. The question was not whether electricity could do the work, but whether any electrical company knew enough about the practical difficulties to attack and overcome them. That point being settled, the remainder was easy. The contract for the Erie Colliery haulage-plant was signed in January, 1889. This colliery is owned by the Hillside Coal and Iron Company, Mr. Samuel Hines, President, and Captain W. A. May, Superintendent. The company has been using arc-lamps in its breakers for three years. It is the only company in the Lackawanna Valley which has had enterprise enough to do so. Consequently, it was acquainted

Jan 1, 1890

By J. O. Lewis, H. R. Pierce

Since the sudden revival of the air or gas-lift and its extensive use in the oil fields, many questions have arisen as to principles and as to their application under the conditions actually encountered in the field. Much has been written regarding both theory and practice, especially on the air-lift as applied to lifting water. Many statements have been made as to the use and benefits of the gas-lift, some of which are reasonable but many of which are unreasonable, many specialty makers claiming to have devices which operate in almost miraculous ways and even to generate energy nature never possessed. These claims are often based upon incomplete or inaccurate data. A review of the literature discloses many valuable articles, but it also discloses the need for setting out more clearly the different practical ends sought, and for working out specific engineering principles upon which to formulate the design and operation of gas-lifts to meet the desired ends within the limitations of field conditions. A check on some of the published information has revealed basic errors in the sources of data upon which conclusions have been predicated and has led the writers to doubt the value of a large part of the compiled data. The writers have concluded, therefore, that it will be opportune to direct discussion to the sources of error in the data now being collected, to recommend for consideration by the engineers some methods of collecting and correlating data, and to point out some of the factors relating to the application of the air-lift principle to oil production as dictated by the different economic ends sought, and the limitations of working conditions that may be met. Until these several considerations are clearly understood by the engineers, and the unreliable data have been sifted out and dependable data substituted, there seems little chance of evolving satisfactory engineering control for the air-lift. In the following pages no distinction will be made between gas-lift and air-lift, as they are generically the same.

Jan 1, 1928

By E. H. Kelton

THE purposes of this paper are to describe the use of adjustable cut and draw tools as a control test of drawing properties and to point out that no other well-known test or combination of tests determines this quality in zinc and zinc alloys. Rolled zinc has been used for making drawn articles, particularly battery cans, for many years. The development of rolling treatments satisfactory for, these purposes followed the usual course of trial and error experimentation depending upon cooperation with customers to determine what type of material was suitable. A quick test of drawing quality was highly desirable, of course. Scleroscope hardness and temper,1 having no apparent relation to drawing quality, were used simply to check the duplication of rolling treatment and grade of metal. The dynamic ductility1 test, on the other hand, was believed to be so like the drawing operation as to provide a reliable index and came to be taken as the criterion of good drawing properties. Faith in this test was strengthened by the fact that metal having the highest ductility was more satisfactory for operations, such as the manufacture of battery cups, that required several redraws. No distinction was made at that time in specifying metal as to whether it was to be subjected to simple cut and draw, redrawing or forming operations. It developed, however, that in some grades of metal the highest ductility did not coincide with the most satisfactory quality when the material was used for a single draw.

Jan 1, 1934

By J. L. Lamon, W. Crafts

Study with the electron microscope of the carbides in vanadium-chromium-molybdenum steels after tempering up to 1000 hr at 600 teelsto 1400°F confirmed that alloy carbides are formed at the secondary hardening temperature by decomposition of the plate-like iron carbides. It was also demonstrated that vanadium carbide persists as much smaller particles than do chromium- or molybdenum-bearing carbides. Conditions conducive to the formation of fine vanadium carbides are indicated to be favorable for high temperature strength. IN order to determine the effects of long exposure at high temperatures on vanadium-bearing steels, a survey has been made of their hardness and carbide structure. The behavior of carbides in the tempering of martensite was studied by X ray diffraction and electron microscope examination of electrolytically extracted residues in greater detail than in an earlier investigation.' A group of steels with about 0.25 pct carbon and containing chromium up to 5 pct, molybdenum up to 1 pct, and vanadium up to 1 pct was either quenched or annealed and then tempered for peri- ods of up to 1000 hr at 600° to 1400°F. Their hardness after tempering agreed with the Hollomon and Jaffe2 relation of equivalency of time and temperature, and with the degree of secondary hardening predicted from composition. Further, the appearance of the carbides indicated that the time and temperature equivalency relation was also applicable to the degree of carbide development. The mechanism of the tempering of martensite was demonstrated more clearly than in the earlier study. It was confirmed that carbides develop from martensite as poorly defined plates of the Fe2C type carbide followed by thickening of the plates with a transition to Fe,C. Finally the plate structure deteriorates into a lacy mass from which alloy carbides emerge as chunky particles that grow slowly with further increase of tempering temperature. Vanadium carbide derived from tempered martensite was found in characteristically small particles that tended to grow very slowly. The addition of chromium or molybdenum to a steel with predominant vanadium carbide tended to introduce carbides of a chromium- or molybdenum-bearing type having a somewhat larger particle size. The Cr,C, type carbide particles were larger than those of the V,C, type and somewhat smaller than the carbides in steel containing both Cr,C and M,C. Similar observations were made of the carbides in the pear lite of annealed steels. It appeared that high temperature properties would be benefited by the retention of the fine carbide particles that result from a balance of composition and heat-treatment designed to produce a maximum amount of vanadium carbide. Procedure: The steels used in the investigation were made with a base of Armco iron in a high-frequency furnace at the Union Carbide and Carbon Research Labs., Inc. The steels were deoxidized

Jan 1, 1951

By J. K. Stanley, R. F. Meel

The recrystallization of cold-worked metals is studied ordinarily by determining the temperatures required for complete recrystallization to occur within a given arbitrary time period, usually within 15 min. to 2 hr. The results obtained are conventionally assembled in a three-dimensional diagram relating this temperature to the amount of cold-work (percentage deformation) and the resultant grain size, though sometimes other modes of representation are emp1oyed.l Such three-dimensional diagrams are not complete, for the number of variables exceeds the number represented. The process of recrystallization is characterized by a time-rate, a fact that is not portrayed upon ordinary recrystallization diagrams. It is known that recrystallization consists in the formation of new nuclei and the growth of these nuclei, a process that continues until the matrix is completely consumed and the original set of grains entirely replaced by the new. This knowledge is old.2 Truly heterogeneous reactions invariably proceed by nucleation and growth; the decomposition of eutectoid solid solutions provides an example about which much is known,3 and freezing, originally studied by Tammann, provides the classic example. Although recrystal- lization is not a heterogeneous reaction within the orthodox meaning of the term, the mechanism of the process is the same. As in eutectoid inversion and freezing, it should be possible to study the rate of isothermal recrystallization as a function of time, and it should also be possible to analyze the isothermal reaction curve into the component rates of nucleation and growth that determine them.* Other methods, not employing the rates of nucleation and growth, have been used to represent the rates of such reactions, but these in general have been artificial and have not led to progress. 4,5 The theory of recrystallization is not in advanced state; if recrystallization data were obtained in terms of the rate of isothermal recrystallization, and in terms of the rate of nucleation and the rate of growth of recrystallized grains, and in particular if the temperature coefficients of these rates were measured accurately, an adequate theory should be more readily developed.27 Such an effort requires proper experimental technique, but especially requires suitable methods of mathematical analysis to convert mcasurements made upon a surface of polish into values for the rate of nucleation and the rate of growth and to combine these into a rate of isothermal recrystallization. These methods are now available for the case of three-dimensional recrystallization (recrystallization of

Jan 1, 1942

By R. F. Meel, J. K. Stanley

The recrystallization of cold-worked metals is studied ordinarily by determining the temperatures required for complete recrystallization to occur within a given arbitrary time period, usually within 15 min. to 2 hr. The results obtained are conventionally assembled in a three-dimensional diagram relating this temperature to the amount of cold-work (percentage deformation) and the resultant grain size, though sometimes other modes of representation are emp1oyed.l Such three-dimensional diagrams are not complete, for the number of variables exceeds the number represented. The process of recrystallization is characterized by a time-rate, a fact that is not portrayed upon ordinary recrystallization diagrams. It is known that recrystallization consists in the formation of new nuclei and the growth of these nuclei, a process that continues until the matrix is completely consumed and the original set of grains entirely replaced by the new. This knowledge is old.2 Truly heterogeneous reactions invariably proceed by nucleation and growth; the decomposition of eutectoid solid solutions provides an example about which much is known,3 and freezing, originally studied by Tammann, provides the classic example. Although recrystal- lization is not a heterogeneous reaction within the orthodox meaning of the term, the mechanism of the process is the same. As in eutectoid inversion and freezing, it should be possible to study the rate of isothermal recrystallization as a function of time, and it should also be possible to analyze the isothermal reaction curve into the component rates of nucleation and growth that determine them.* Other methods, not employing the rates of nucleation and growth, have been used to represent the rates of such reactions, but these in general have been artificial and have not led to progress. 4,5 The theory of recrystallization is not in advanced state; if recrystallization data were obtained in terms of the rate of isothermal recrystallization, and in terms of the rate of nucleation and the rate of growth of recrystallized grains, and in particular if the temperature coefficients of these rates were measured accurately, an adequate theory should be more readily developed.27 Such an effort requires proper experimental technique, but especially requires suitable methods of mathematical analysis to convert mcasurements made upon a surface of polish into values for the rate of nucleation and the rate of growth and to combine these into a rate of isothermal recrystallization. These methods are now available for the case of three-dimensional recrystallization (recrystallization of

Jan 1, 1942

By C. W. Washburne

FORMER studies of sedimentary strata have been based upon the mineralogical and mechanical characters of the solid components, rather than upon the open spaces between them. For present purposes let us take another point of view, and consider not the rock material, but rather its cavities, the pores and the fissures or cleaved joints which connect with them. Let us think of the geologic column not as a series of rocks, but as a mass of irregular connecting capillaries. Different parts of the column may be distinguished by the absolute size and by the relative amount of its open spaces. Porosity Each stratum of the column is characterized by a certain porosity, which would be independent of the size of the rock grains if all were of the same shape. Slichter has shown that the percentage of open space in a pile of equal spheres is practically constant regardless of the diameter of the spheres. This is approximately true of clean, assorted sand or gravel, but it is far from being the case with most natural sediments which have a widely variable porosity, the magnitude of which is determined mainly by the amount of fine and of secondary material between the larger grains. The shape of the grains materially affects porosity, round grains leaving more open space than angular or flat grains. The thin plates of kaolin and the fine plastic matter of clay fit quite perfectly when pressed together, and it is probably this close fit, determined by shape of grain, rather than the small size of a grain, that causes the low porosity of ordinary clay shale.

Jan 9, 1914

By G. W. Jones, G. S. Scott

Economic waste caused by mine fires may become considerable,l5 especially if a fire is allowed to spread or temporarily to get beyond control. It is important, therefore, to act promptly whenever a fire is suspected and to make every action count. To contribute toward its extinction effectively it is necessary to know at the earliest possible moment, and continuously thereafter, what is happening at the seat of the fire, which may be in a remote or inaccessible area, and also to recognize what may be expected as a result of any proposed combative measure. In combatting a fire the mining engineer and the chemist should cooperate, first deciding upon the course of action to be taken and then drawing upon the mining engineer's intimate knowledge of the physical structure of the fire area, the cost and time required to carry out proposed operations, and the probable efficiency with which these operations could be performed, and upon the chemist's knowledge for the results to be expected therefrom. After the initial steps to be taken have been decided, it devolves upon the mining engineer to see that they are carried out and upon the chemist to evaluate the results and to keep the mining engineer continuously informed in regard to a variety of matters—such as the composition and toxic or asphyxiating properties of the atmosphere in which the men may be working, whether the fire is increasing or decreasing in intensity and its probable temperature, the quantity of air leakage and the explosion hazards of the fire area. The purpose of this paper is to discuss what the chemist can and cannot contribute as a member of the fire-fighting personnel. The technical literature contains several hundred papers relating directly and indirectly to mine fires, and this fact alone is testimony to the complex nature of the phenomena involved in the birth, life, and final demise of a fire. A fire may be stopped (I) by preventing oxygen from reaching the coal or (2) by removing the conditions necessary for the rapid reaction of coal with oxygen; i.e., decreasing the temperature. All methods of prevention or control necessarily must be based upon one or the other, or both, of these two principles. The chemistry of a fire may be understood readily if the low-temperature oxidation of coal is considered as a starting point; then oxidation at higher temperatures (or combustion); and with these, the composition of the solid and gaseous products resulting from the oxidation or from the effects of the heat liberated. This discussion refers particularly to Pennsylvania anthracite, although much of the material applies equally well to coals of lower rank. Oxidation of Coal Oxidation of coal fundamentally is confined to the surface; that is, the rate at which oxygen penetrates into the interior of a solid block of coal is so slow that it may be ignored."16 Oxidation starts when a fresh surface is exposed, and the rate is

Jan 1, 1942

By G. S. Scott, G. W. Jones

Economic waste caused by mine fires may become considerable,l5 especially if a fire is allowed to spread or temporarily to get beyond control. It is important, therefore, to act promptly whenever a fire is suspected and to make every action count. To contribute toward its extinction effectively it is necessary to know at the earliest possible moment, and continuously thereafter, what is happening at the seat of the fire, which may be in a remote or inaccessible area, and also to recognize what may be expected as a result of any proposed combative measure. In combatting a fire the mining engineer and the chemist should cooperate, first deciding upon the course of action to be taken and then drawing upon the mining engineer's intimate knowledge of the physical structure of the fire area, the cost and time required to carry out proposed operations, and the probable efficiency with which these operations could be performed, and upon the chemist's knowledge for the results to be expected therefrom. After the initial steps to be taken have been decided, it devolves upon the mining engineer to see that they are carried out and upon the chemist to evaluate the results and to keep the mining engineer continuously informed in regard to a variety of matters—such as the composition and toxic or asphyxiating properties of the atmosphere in which the men may be working, whether the fire is increasing or decreasing in intensity and its probable temperature, the quantity of air leakage and the explosion hazards of the fire area. The purpose of this paper is to discuss what the chemist can and cannot contribute as a member of the fire-fighting personnel. The technical literature contains several hundred papers relating directly and indirectly to mine fires, and this fact alone is testimony to the complex nature of the phenomena involved in the birth, life, and final demise of a fire. A fire may be stopped (I) by preventing oxygen from reaching the coal or (2) by removing the conditions necessary for the rapid reaction of coal with oxygen; i.e., decreasing the temperature. All methods of prevention or control necessarily must be based upon one or the other, or both, of these two principles. The chemistry of a fire may be understood readily if the low-temperature oxidation of coal is considered as a starting point; then oxidation at higher temperatures (or combustion); and with these, the composition of the solid and gaseous products resulting from the oxidation or from the effects of the heat liberated. This discussion refers particularly to Pennsylvania anthracite, although much of the material applies equally well to coals of lower rank. Oxidation of Coal Oxidation of coal fundamentally is confined to the surface; that is, the rate at which oxygen penetrates into the interior of a solid block of coal is so slow that it may be ignored."16 Oxidation starts when a fresh surface is exposed, and the rate is

Jan 1, 1942

By D. H. Henley, F. F. Craig, W. W. Owens

The oil recovery performance of systems producing entirely by bottom-water encroachment has been experimentally determined in a series of scaled laboratory-model tests. The effects of well spacing, fluid mobilities, rate of production, capillary and gravity forces, well penetration and well completion techniques on the oil recovery performance have been investigated. The laboratory tests were performed using two uniform, un-consolidated sand-pack models. The models have ratios of the interwell distance to the formation thickness of 12 and 2, respectively. Tests at constant total fluid production rate were performed simulating a range of uniform reservoir characteristics and operating conditions encountered in field operations. The performance was determined by material balance and by observation of the encroachment of dyed fluids into the models. The results of the model tests agreed with those obtained mathematically when the conditions previously considered in theoretical studies were simulated, that is, when the oil and water are of equal density and no capillary forces exist. The model study of bottom-water drive indicated that certain variables can aoect the oil recovery performance to a greater degree than can be predicted by present analytical methods. In one comparison, the oil recovery at a water-oil ratio of 20 (obtained at a wide well spacing) varied as much as threefold, depending upon the system's properties and the production rate. Lesser effect of mobility ratio and no eflect of capillary forces over the range studied were observed. The test 'results also showed that the deeper the well penetration into the oil column, the greater the total water production to a producing WOR of 20. However, the ultimate sweep efficiency, and so the oil recovery to this level of WOR, did not vary significantly with well penetration. Horizontal fractures at the top of the formation did not significantly change the sweep characteristics of the reservoir models when values of radius and fracture capacity encountered in actual reservoirs were used. Impermeable pancakes at the bottom of the well moderately increased the oil recovery efficiency both at water breakthrough and at high water-oil ratios. A method is outlined by which the oil recovery performance of other uniform bottom-water drive systems can be estimated from the information obtained in these model tests. INTRODUCTION When oil is produced from a well which partially penetrates an oil zone completely underlain by water, the water rises directly beneath the well in a symmetrical cone when the system is uniform. Two different flow mechanisms can cause the water cone to form—coning and bottom-water drive. In coning, the aquifer is relatively inactive and the cone is formed beneath the well by the pressure gradients associated with the oil flow to the well. The oil can be produced by a solution-gas drive, an edge-water drive or other driving forces in the interwell area. In a bottom-water drive, the driving force for oil production comes from an upward encroachment of the underlying active aquifer. Two papers have analyzed the theoretical performance characteristics of bottom-water drive reservoirs. In the initial mathematical investigation, Muskat' established the equations which determine the pressure distribution in this type of reservoir and solved these equations for certain conditions. Specifically, it was assumed that the water and oil had equal mobilities and equal densities, there were no capillary forces, the pressure throughout the oil zone remained above the bubble-point pressure, a constant pressure existed at the initial water-oil contact and the oil was completely displaced by the encroaching water. These assumptions were used in obtaining analytical solutions. In general, Muskat found that the sweep efficiency to initial water breakthrough to the well was larger for the thicker oil zones, the closer well spacings, the lower ratios of vertical to horizontal permeabilities, the smaller the penetration of the well into the oil zone and the smaller the bore size of the well. The production history after water breakthrough was expressed as a volumetric sweep efficiency at a given producing water-oil ratio. The results indicated that cumulative oil production at producing water-oil ratios of 10 is less affected by the well spacing than is the water-free production history. Muskat studied well spacing which today would be regarded as close. The maximum value of his dimensionless well spacing (ratio of interwell distance to formation thickness) was 4.3. This would require the development of a 50-ft-thick oil sand on less than 10-acre spacing if the vertical and horizontal permeabilities were equal, with

By E. V. Potter, H. C. Lukens

In general, during all electrowinning processes, large volumes of gas are liberated at the cathodes of the electrolytic cells. Most of this gas escapes from the electrolyte, but much of it may be absorbed or entrapped in the metal being plated. In many cases, this is not objectionable, but since it is liberated when the metal is heated, it is a potential source of trouble where the metal has to be heated or melted. Since this gas is principally hydrogen, in escaping from a melt it may cause minor explosions and scattering of the molten metal, while in other cases it has been reported to make the metal rise in the molds when cast. Therefore such metals would be more generally useful if all or most of the gas were removed before they were used. In an earlier investigation1 the gas content of electrolytic manganese was determined and methods found for removing most of it without detrimentally affecting the properties of the metal. In this paper results of a similar investigation on electrolytic chromium are presented. Apparatus The apparatus used in these investigations is essentially the same as that used in the manganese work1 and is shown in Fig I. It consists of sample chamber A, vacuum or pressure gauge B, volume gauge C, vacuum pump D, hydrogen container E, auxiliary gas chamber F, and furnace G. The pressure in the system is measured by the mercury manometer B. Changes in gas volume are measured by volume gauge C which is essentially another mercury manometer in which the volume of the mercury column is large and can be varied by raising or lowering the well H. In this apparatus the tube had a volume of 100 cc for a 60 cm length. Larger changes in gas volume can be accommodated by auxiliary containers attached to the system at F. The sample is heated by furnace G, the temperature of which is regulated within 5°C by an automatic controller. The only change in the apparatus was the sample container which was made smaller because of the chromium metal's containing more gas than the manganese metal and a smaller sample was used. Method The measurements were made as follows: The complete system when cold was evacuated and refilled with H2 until all the air was removed. It was then refilled with H2 to the desired pressure, as indicated on manometer B. The temperature was then raised to the desired value and as gas was either liberated from or absorbed by the sample, the height of well H was changed to alter the volume of the system so as to keep the pressure constant. In determining rates of liberation of gas, volume readings were taken at convenient tirne intervals depending on the rapidity with which the gas was liberated. In determining total volumes, the specimen was held at constant temperature and pressure until

Jan 1, 1949

By Carle Hayward

AT THE February, 1916, meeting of the Institute, a paper presented by Hayward and Raymond gave the results of a study on the effect of time in tempering medium-carbon steel, when the following conclusions were reached: It is not fair to consider the question settled when only three specimens were used for each treatment, but the results obtained indicate that for reheating quenched medium-carbon steel to temperatures below 500° it is only necessary to heat it through. Longer heating has little or no effect on the tensile strength, ductility, or hardness. At temperatures above 500°, increasing the time of treatment causes a slight falling off in hardness and tensile strength with a corresponding increase in ductility. In the discussion of the paper these conclusions were attacked and evidence presented that seemed to throw doubt on their accuracy. The authors, however, showed that this evidence was based on high-carbon or alloy steels and no facts regarding medium-carbon steel were presented. During this study the heat treatment was carried out in a small electric resistance furnace. It held nine specimens, but when these were placed in the furnace the temperature was lowered to such an extent that 30 to 40 min. were required to reach the desired heat. The authors pointed to this as a weak point in the investigation and it seemed wise to supplement the research by work on similar steel but using a different method of heating. This has been done and the results are given in the present paper. The Rhode Island Tool Co. cooperated by furnishing the steel and turning the tensile specimens.

Jan 1, 1922