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By Carl F. Floe, Michael B. Bever

The solubility of hydrogen in molten copper-tin alloys is of both practical and theoretical interest. From a practical standpoint, data on the equilibrium solubility as a function of temperature, pressure and alloy composition are valuable for a better understanding of porosity problems in bronze castings. From the theoretical point of view the determination of the hydrogen-copper-tin equilibrium is of interest since it extends the laws governing the solution of gases in metals. This paper presents the results of an investigation of the solubility of hydrogen in representative compositions of the copper-tin system at temperatures ranging from above the liquidus to I300°C. and at pressures from less than 50 mm. of mercury to about atmospheric. Review of Previous Work The solubility of hydrogen in copper was determined by Sieverts and Krumbhaarl in 1910 and by Roentgen and Moeller2 in 1934. Their values are in fair agreement. In 1926 Iwasé3 reported results that were very much higher. The published data on the solubility of hydrogen in tin do not agree. Smithells4 states that no reliable data are available According to Sieverts and Krumbhaar,5 hydrogen is insoluble in tin. Bircumshaw,6 on the other hand, found a definite solubility at 800°C. The latter's experimental procedure did not provide for stirring of the metal and in his opinion he failed to reach equilibrium. Iwasé3 again reported large solubility values. For copper alloys, Sieverts and Krumbhaar5 distinguished between alloying elements that do not markedly affect the solubility of hydrogen, elements that increase the solubility, and elements that reduce it. They named gold, tin, and aluminum as examples of this last group and reported hydrogen solubility data at 1225°C. for the copper-rich side of these alloy systems at atmospheric pressure. Without giving experimental results, they stated that the amount of hydrogen dissolved by liquid copper alloys is proportional to the square root of the pressure as in pure metals. These authors suggested that in a limited way the effect of an alloying element on the solubility of a gas is related to the constitution diagram for the alloy system. Sieverts7 also called attention to the fact that the curve of hydrogen solubility versus composition of copper-tin alloys shows a sharp change of direction at the composition of Cu3Sn and suggested that this compound persists at least to some extent in the molten state. Iwasé3 reported large hydrogen solubility values for several compositions of copper-tin alloys, which appear to be in error.

Jan 1, 1944

CONTENTS PAGE THOENEN, J. R.-Limestone Production as a Mining Problem. Discussed by Oliver Bowles, J. T. Singewald, S. R. Russell 1 GRIGGS, C. C.-Engineering in Limestone Production. Discussed by W. C. Phalen, John Rice, Samuel M. Shallcross, Oliver Bowles, Nathan C. Rockwood, George Milliron 2 WILDER, FRANK A.-Rotary Calciners for Gypsum. Discussed by L. K. Arm-strong 9 PORTER, JOHN J.-Manufacturing Problems of Cement Industry. Discussed by Samuel M. Shallcross 9 KIRKHAM, VIRGIL R. D.-Phosphate Deposits of Idaho and Their Relation to the World Supply. Discussed by F. A. Wilder, S. L. Willis, G. R. Mansfield, R. W. Stone, L. K. Armstrong 9 Limestone Production as a Mining Problem Discussion of the paper of J. R. THOENEN, presented at the New York Meeting, February, 1925, and issued, as Paper 1417-H, with MINING AND METALLURGY, February, 1925. OLIVER BOWLES, New Brunswick, N. J.-I am so thoroughly convinced of the growing importance of underground work in the production of limestone that I had the author make a detailed study of limestone mining for the Bureau of Mines and prepare a report on the principles of limestone mining. Many limestone operators, long accustomed to open¬pit work, are being forced to mining. About 6 months ago I thought there were twenty-five or thirty underground limestone operations in the United States but the author has been finding new ones until his list now runs nearer sixty. Some of these are very extensive; one at least has 4 ½ miles of underground workings. There is an ever-expanding field for the engineer in the operation of limestone mines and quarries. Some of the larger companies realize the need of skilled engineering advice, but many of the companies regard the engineer as an unnecessary expense. Although almost every metal mine, even those handling only a few hundred tons of ore per month, employs a mining engineer, many limestone operations ten times as large employ no mining engineers. Few mining engineers are at all familiar

Jan 6, 1925

By Willis R. Battles, William F. Cerini, P. H. Jones

A test for determining the plugging characteristics of an oil-well injection water has been developed. It consists in measuring changes of the filter rate of a water at constant pressure with cumulative throughput when passing the water through a medium grade sintered glass disk. Application of the test method was made to the water used in the Union Oil Company's experimental water flood of the Chapman zone in the Richfield field, Orange County, Callfornia. This water developed increasing plugging tendencies upon aging, even though the finished water from the plant filter exhibited few such characteristics. The plugging material was found to consist of calcium carbonate, ferric hydroxide, and organic substances that were presumed to be bacterial. Various method of stabilizing this water to prevent the formation of plugging material were attempted. Lowering the pH to approximately 6.4 by injecting carbon dioxide provided a moderately satisfactory means for stabilization but a better method of stabilizing this water was found to be first aging and then filtering. Introduction An experimental water-flood project was started on the Chapman zone of the Richfield field in March 1944 and has been described in a previous paper.' It consists of a single injection well drilled between old producing wells. A water-treating plant using primary alum flocculation, sedimentation and chlorination followed by secondary flocculation, sedimentation and fltration is employed to process the water before in@ion. In all of the water-treating operations, the system is open to the air, and no attempt is made to prevent the loss of carbon dioxide or absorption of oxygen by the water. The clear water is stored in a covered concrete basin and pumped through a Transite line to the suction of a high-pressure pump at the injection well' The high-pressure tubing in the well to the injection zone is cement lined. The untreated injection water is a mixture produced with the oil from the Chapman and Kraemer zones and is supplied from the disposal system. Because the injection well was relatively deep (injection zone about 3400 ft.) and would be expensive to replace, it was believed imperative to supply a nonplug-ging injection water and to develop laboratory procedures for evaluating the treated injection water with respect to its formation plugging properties. This report describes the development and application of the test procedure based on the assumption that the plugging properties could be determined by measuring the progressive decrease in flow rate of the water through a porous medium. If the quality of the injection water was good enough so that the plugging action on the porous medium was of small magnitude, it was reasoned that the tendency to impair flow in the formation would not be serious.

Jan 1, 1946

By E. N. Cameron, H. M. Bannerman

During the years 1942-1934, about 125 New England deposits were mined for sheet and punch mica, and many others were briefly prospected. During this period the Geological Survey, United States Department of the Interior, carried on detailcd studies of the deposits and the pegmatite bodies that contain them. The primary purpose of the studies was to provide geological information that would contribute toward efficient mine development and operation. The studies were aimed directly at practical production problems. Detailed maps showing the structure of the deposits were prepared, and geological findings were closely correlated with data on specific yields and costs of mining and processing. The result is information that permits a reasonably accurate appraisal of the mica deposits of New England and the mining industry that they support. At a time when the future of the industry is in doubt, it seems desirable to submit this appraisal for consideration. Domestic mica deposits supply only a small fraction of the country's needs in normal times? for only the richest domestic deposits can compete with the low-cost mines of India and Brazil. However, the possibility that this country may be cut off from its supplies in time of war gives domestic deposits an importance much greater than their peacetime production would imply. New England supplied about 22 per cent of domestic output in 1943 and 1944, the peak years of wartime production. Its actual contribution to the war effort was greater, for the proportion of sheet mica of high quality in the New England product is higher than the average for domestic mica. The data analyzed below were collected for the Geological Survey by D. M. Larra-bee, A. H. McNair, J. J. Page, V. E. Shai-nin, G. W. Stewart, and the co-authors of this paper. The cooperation of officials of Colonial Mica Corporation and of mine operators and owners in furnishing information is gratefully acknowledged. D. M. Larrabee, A. H. McNair, and V. E. Shainin have made various suggestions based on critical reading of the manuscript. Analysis oF Warrtime Operations In considering the data presented in this report, it must be remembered that the scale of mica operations is very small compared with that of many other mining industries. The typical New England mica mine of 1943 and 1944 was worked by a crew of five or six men. Equipment was varied but on the whole extremely simple. The first stage of operation at a deposit was normally opencut mining. Drilling was done mostly with jackhammers powered by portable compressors driven by gasoline engines. Muck was shoveled by hand into buckets with a capacity of 45 to 35 ton and commonly hoisted by derrick to a dump adjacent to the cut. As operations were carried to greater depth, and the tram sition to underground mining was made, these methods were modified to a degree depending largely on the attitude of the deposit mined. At steeply dipping deposits,

Jan 1, 1948

By P. B. Crawford, W. L. Huskey

A study has been made to determine the effects of random vertical fractures existing in a reservoir matrix on the effective matrix properties and producing characteristics of a well. The study indicated that short vertical fractures may distort the isopotentials by 1 percent in the vicinity of the fracture. A correlation was developed which showed the effect of fracture density on the producing capacity of a well. The correlation indicated that fracture shape had little effect on producing capacity, but that total fracture length was closely correlated with the producing capacity. Effective values of reservoir permeability were found to correlate closely with fracture density when measured parallel to the direction of flow. INTRODUCTION In reviewing the petroleum literature, it is found that in most analytical solutions of hydrocarbon reservoir behavior the assumption is made that the rock is uniform throughout although core analysis and well logging surveys indicate that substantially all reservoirs are heterogeneous and some are fractured. Only in recent years have investigators studied the effects of reservoir hetrogeneity. Russell1 discussed the effect of fractures in reservoirs. The literature indicates that fractures greatly affect the exploitation of man reservoirs. This is described by Elkins and Skov2 and Little-field et al. 3 Several types of reservoir heterogeneity have been studied by unsteady-state methods. In 1959, Landrum et al. 4 showed that transient phenomena in hydrocarbon reservoirs could be studied by thermal models. pickering5 studied the flow of heat in stratified linear reservoirs consisting of plates of different metals separated by sheets of rubber which were suddenly exposed to a low-temperature source at one end. Cotman6 studied both laterally and vertically heterogeneous thermal model reservoirs with special reference to cross flow. Another type of reservoir heterogeneity involves the presence of highly permeable, circular lenses around or near the wellbore which was studied by Miesch7 using a thermal and a steady-state model. Many studies have been made of the effects of induced hydraulic fractures on well performance. 8-10 Work regarding vertical fractures that exist initially in the reservoir was reported by Givens, et al.11 Since there appears to be little published work on the importance and influence on reservoir performance of fractures that exist out in the rock matrix, this study was conducted to determine the effects of vertical fractures on pressure distribution, producing capacity and the effective permeability of the reservoir rock. The analogy between the flow of electrical current through a conducting body and the flow of fluid in a porous medium provides a convenient method of studying various aspects of petroleum reservoirs. For electrical radial steady-state flow,12 For steady-state fluid flow, With the above analogy, it is only necessary to establish the ratio of the values of the electrical units in terms of the corresponding flow units to make the analogy quantitative. The ratios are shown below.

By H. M. Bannerman, E. N. Cameron

During the years 1942-1934, about 125 New England deposits were mined for sheet and punch mica, and many others were briefly prospected. During this period the Geological Survey, United States Department of the Interior, carried on detailcd studies of the deposits and the pegmatite bodies that contain them. The primary purpose of the studies was to provide geological information that would contribute toward efficient mine development and operation. The studies were aimed directly at practical production problems. Detailed maps showing the structure of the deposits were prepared, and geological findings were closely correlated with data on specific yields and costs of mining and processing. The result is information that permits a reasonably accurate appraisal of the mica deposits of New England and the mining industry that they support. At a time when the future of the industry is in doubt, it seems desirable to submit this appraisal for consideration. Domestic mica deposits supply only a small fraction of the country's needs in normal times? for only the richest domestic deposits can compete with the low-cost mines of India and Brazil. However, the possibility that this country may be cut off from its supplies in time of war gives domestic deposits an importance much greater than their peacetime production would imply. New England supplied about 22 per cent of domestic output in 1943 and 1944, the peak years of wartime production. Its actual contribution to the war effort was greater, for the proportion of sheet mica of high quality in the New England product is higher than the average for domestic mica. The data analyzed below were collected for the Geological Survey by D. M. Larra-bee, A. H. McNair, J. J. Page, V. E. Shai-nin, G. W. Stewart, and the co-authors of this paper. The cooperation of officials of Colonial Mica Corporation and of mine operators and owners in furnishing information is gratefully acknowledged. D. M. Larrabee, A. H. McNair, and V. E. Shainin have made various suggestions based on critical reading of the manuscript. Analysis oF Warrtime Operations In considering the data presented in this report, it must be remembered that the scale of mica operations is very small compared with that of many other mining industries. The typical New England mica mine of 1943 and 1944 was worked by a crew of five or six men. Equipment was varied but on the whole extremely simple. The first stage of operation at a deposit was normally opencut mining. Drilling was done mostly with jackhammers powered by portable compressors driven by gasoline engines. Muck was shoveled by hand into buckets with a capacity of 45 to 35 ton and commonly hoisted by derrick to a dump adjacent to the cut. As operations were carried to greater depth, and the tram sition to underground mining was made, these methods were modified to a degree depending largely on the attitude of the deposit mined. At steeply dipping deposits,

Jan 1, 1948

By T. A. Wright

THE SAMPLING of waste materials containing copper, lead and tin has taken on a new significance within recent years, and is of increasing importance, on account of the entry of some of the copper refineries into this field and the tendency towards consolidations among the smelters. In the past, such material was sold on the basis either of a rough or grab sample or of casual inspection of the lot. The two principal sources of this waste are the processes of fabrication and the scrapping of automobile, electrical, plumbing, railroad and other equipment. In both cases much material can be sorted, salvaged and sold by classification and grade to be melted "as is" or with the addition of new or virgin metal. The increasing care in classifying exercised in the large manufacturing plants tends to increase the proportion of this usable scrap; on the contrary, the increasing use of more complex and special non-ferrous alloys tends to make sorting and grading more difficult in turnings, borings, clippings, etc., and consequently is making sampling of more moment. In tin, lead, aluminum, and zinc furnace by-products such as ashes, drosses, skimmings, etc., the trade practice of evaluation has not varied much. For instance, tin drosses, battery lead, and aluminum skimmings are ordinarily sold on what is called "metallic button" or "metallic recovery" or "metallic yield." Copper and lead waste, however, is being sold more and more on actual copper and lead contents based on sample and chemical analyses. This paper will be devoted chiefly to the sampling of materials suitable only for refining and recovery of one or more of the metals present. The methods described are often based on the fact that but one metal, such as copper, is to be paid for. The loss of volatile constituents in melting does not appreciably affect the final copper result, as the "after-melting" assay can be readily calculated to the "before-melting" basis, but if smelter efficiency continues to increase, so that in time zinc, for instance, may be recovered on a paying basis, the method of sampling dirty brass, for example, will have to be changed also.

Jan 1, 1928

By William F. Cerini, Willis R. Battles, P. H. Jones

A test for determining the plugging characteristics of an oil-well injection water has been developed. It consists in measuring changes of the filter rate of a water at constant pressure with cumulative throughput when passing the water through a medium grade sintered glass disk. Application of the test method was made to the water used in the Union Oil Company's experimental water flood of the Chapman zone in the Richfield field, Orange County, Callfornia. This water developed increasing plugging tendencies upon aging, even though the finished water from the plant filter exhibited few such characteristics. The plugging material was found to consist of calcium carbonate, ferric hydroxide, and organic substances that were presumed to be bacterial. Various method of stabilizing this water to prevent the formation of plugging material were attempted. Lowering the pH to approximately 6.4 by injecting carbon dioxide provided a moderately satisfactory means for stabilization but a better method of stabilizing this water was found to be first aging and then filtering. Introduction An experimental water-flood project was started on the Chapman zone of the Richfield field in March 1944 and has been described in a previous paper.' It consists of a single injection well drilled between old producing wells. A water-treating plant using primary alum flocculation, sedimentation and chlorination followed by secondary flocculation, sedimentation and fltration is employed to process the water before in@ion. In all of the water-treating operations, the system is open to the air, and no attempt is made to prevent the loss of carbon dioxide or absorption of oxygen by the water. The clear water is stored in a covered concrete basin and pumped through a Transite line to the suction of a high-pressure pump at the injection well' The high-pressure tubing in the well to the injection zone is cement lined. The untreated injection water is a mixture produced with the oil from the Chapman and Kraemer zones and is supplied from the disposal system. Because the injection well was relatively deep (injection zone about 3400 ft.) and would be expensive to replace, it was believed imperative to supply a nonplug-ging injection water and to develop laboratory procedures for evaluating the treated injection water with respect to its formation plugging properties. This report describes the development and application of the test procedure based on the assumption that the plugging properties could be determined by measuring the progressive decrease in flow rate of the water through a porous medium. If the quality of the injection water was good enough so that the plugging action on the porous medium was of small magnitude, it was reasoned that the tendency to impair flow in the formation would not be serious.

Jan 1, 1946

By E. L. Bruce

The district of Patricia, in the province of Ontario, lies northwest of the Albany River and extends northward to Hudson Bay. Formerly this was the unorganized district of Keewatin, the southern part of which was divided in 1912 between the provinces of Manitoba and Ontario. The interprovincial boundary now runs north from Lake of the Woods for 275 miles and thence northeast 375 miles to Hudson Bay. This district is comparable in size to all the older part of Ontario south of the Canadian Pacific Railway east of Lake Huron—thus it is roughly one-third of the whole of the present provincial area. The central part of this great triangle is one of the least accessible parts of Canada. From it streams flow southward to the English River, southeastward to the Albany, northward to Hudson Bay and the Hayes River, and westward to Lake Winnipeg. None of the streams is large and canoe travel is not easy. The only industry it has ever had is the trade in furs. Until the development of the airplane on a commercial basis, the only means of travel was by canoe or dog-train. There is not a mile of railway in the whole district. The two areas to be dealt with lie in the southwestern part of Patricia. Red Lake is 50 miles east of the Manitoba boundary and 75 miles north of the transcontinental railway from Cochrane to Winnipeg. Woman Lake is 50 miles farther east and slightly farther north. The late Dr. D. B. Dowling, of the Geological Survey of Canada, visited Red Lake and spent some time there during his exploration survey from Lac Seul to Berens River in 1893. He also visited the Woman Lake basin during the same journey, but his examination of it was much less detailed, the great area covered by him during the one field season making it impossible to make more than a hurried reconnaissance. Some prospecting in the Red Lake district followed Dowling's exploration, but the distance from railway was too great for any systematic work to be done. In 1922, following the usual plan, the Ontario Department of Mines made a geological reconnaissance of the English River, following :in instrumental survey of that river and its lakes by the Department of Lands. A side trip was taken to examine the rocks of Red Lake described

Jan 1, 1928

By Robert R. Brookshire

Brush plating has been thought of by many as black magic bordering on alchemy. Actually it is a science that uses both electro-chemical and mechanical engineering skills and technology. We are not sure when brush plating was first used or by whom. I do know that many times when we would put in for patents on things we thought of as new and innovative, we would find that someone had done it many years before. It took World War I1 to get brush plating off and running. Now at this point, someone may be asking just what is brush plating? And why are we plating brushes? One way of describing what brush plating is, is by telling what it is not such as tankless plating. Brush plating-is an electro deposition of an electro-platable element or alloy onto a conductive surface. To do this a source of direct current is required; this can vary widely. I prefer stepless voltage control from 0-35 volts with a capacity depending on the size job to be done. This can vary up to 500 amps for normal applications. In one case we have used 7500 amps.. In the beginning a brush was actually used with a wire in the middle of the bristles and a jelly-like paste made up from tank plating solutions. The bristles were saturated with the gunk and the spot to be plated was muddled with the concoction at a potential which was the same as the applied tank Voltage. Metal was deposited but only thin coats were achieved. Today we use graphite wrapped or covered with cotton to form a Q-tip type anode. By using graphite rather than a specific metal we are able to either plate, de-plate or strip, electro- mill, electropolish, or anodize--all with the same equipment. Only the electrolyte needs to be changed.

Jan 1, 1984

A USEFUL and very ingenious idea was surely that of the inventor of AN a short way of extracting gold and silver from the sweepings of all those arts that handle them as well as every particle that smelters of ores might have left in the slags, and also that in some ores themselves. This is done without using great labor in smelting but by the sole means and virtue of mercury. To do this, first make a large bricked pan of stone or wood and arrange a millstone inside which rotates in the hollow of this pan like that of a flour mill. In the hollow of the pan put some of your material containing gold after it has been crushed well in a mortar and then washed and dried. Grind it in the said mill, moistening it meanwhile with vinegar or water in which sublimate, verdigris, and common salt have been dissolved. Then enough mercury to cover these materials is poured over them. They are agitated inside for an hour or two, by turning the mill either by hand or with a horse, depending on the device that you have arranged. Remember that the more the mercury and the material are rubbed together in the mill the more it can be believed that the mercury absorbs the substance that the materials contain. Finally, thus prepared, the mercury is separated from the earthiness with a sieve or by washing and thus the mercury is retrieved. Then, make it rise with a little cucurbit or pass it through a purse and there will remain at the bottom the gold, silver,. copper, or whatever metal you placed in the pan under the millstone to be ground. Wishing to know this secret, I gave to the one who taught it to me a ring with a diamond worth twenty-five ducats, and I also pledged myself to give him the eighth part of whatever profit I should gain from this

Jan 1, 1942

Discussion of the paper of L. O. HOWARD, presented at the Salt Lake meeting, August, 1914, and printed in Bulletin No. 91, July, 1914, pp. 1785 to 1790. E. P. MATHEWSON, Anaconda, Mont.-I would like to add a few words of praise on Mr. Howard's work at the Old Dominion. Mr. Howard has given this particular converter shell his personal attention, and the results are shown in the figures given. Similar converter shells, a little different in shape and of about the same size, have been tried in many plants throughout the United States. The results have been highly satisfactory, but there is no shell of the size of the one described by Mr. Howard that has given anything like the results that Mr. Howard's shell has given. I know of larger shells that have given very good service, and are still in operation, and require very little repair. The main thing about the whole process of using the basic lining in copper converting is to keep the temperature within reasonable bounds, particularly not to get the furnace too hot. If it is overheated a little bit, for say half an hour, an entire lining may be ruined. It is very easy to keep the temperature regulated 'if the mass is large. If you have a large mass in your converter you can easily prevent it from getting over-heated, and that is the big argument in favor of the extra large converters. Of course, there is a limit to what a plant can turn out in the way of matte. Very few plants can supply matte sufficient to keep a converter of 20 ft. in diameter in operation constantly, but the 20-ft. converter is very much superior to the 12-ft. converter in easy handling and absolute control of the temperature. I think Mr. Howard is to be congratulated on the excellent showing he has made.

Jan 12, 1914

By Walter Henoch

THE subject of my talk is, "What 'the college, student expects when he gets out of college." Since all of us, here tonight are engineers, I think it will be proper to limit the discussion to "What the engineering student expects when he emerges from college." It might be well to con-sider just why we chose engineering rather than some other of the many courses open to us. We certainly did not choose it because it is easy nor because we thought it would be a very pleasurable way to spend four years of our lives. The majority of students who choose this profession have a pretty well-formed idea of what an engineering course requires. They at least know that they must work to re-ceive their credits. The minority, which is no small num-ber, are soon disillusioned and as a result they either quit college entirely or they join the' Commerce School. I asked a number of my fellow students just what it was that induced them to join the engineering profession, but it was hard to obtain a clear cut statement from any of them. Some said it was due to environment; others said, they took it because they liked it, and still others said they took it because their folks wanted them to. These state-ments are rather vague and incomplete, but underlying them all is something that the fellows found hard to ex-press. I think it is this: To the layman there is something of romance and adventure about the engineering profes-sion, and this fact coupled with the reputed high salaries and high commands of certain noted engineers no doubt fired our imaginations and consequently led us to join the ranks of the engineers. No doubt many engineers have gone out into the world and have found little romance or adventure .attached to their work, but nevertheless it is an occupation of a wide diversity of interest, of constant change of scene, and of vivid and human relations.

Jan 5, 1928

By Sherwin F. Kelly

THIS is intended as a simple review of the principles and practice of geophysics, so will not be of interest to the geophysicist, who is hereby warned of its elementary character. The engineers for whom it is written are those who, having glimpsed the formidable formulas and discussions of the geophysicists, give all publications on the subject a wide berth. For a few years now the geo-physicists have had a tendency to be ingrowing at their meetings, going deeper and deeper into theory and instrument construction, and forgetting to present the topics that would interest the practicing engineer who desires merely to know how geophysics can help him, not why.

Jan 1, 1934

By Alfred E. Hunt, Geo. H. Clapp

The great advantage to he gained by a careful inspection of all materials used in construction, in regard to safety and permanency, and to accuracy of workmanship, has been longer recognized in Great Britain and on the Continent than in America. This is probably owing to the way in which great enterprises have been " rushed" in the United States. Time and cheap first cost, in too many instances, have been considered of more importance than absolute safety and durability; the structures being afterwards strengthened if this was found necessary. This has been most noticeable in railroads built through " new " country, where the object in view has been to reach the terminal point and get to work. These " loose " methods are now being very largely done away with, and a large proportion of the structures lately built are not only carefully inspected during the process of

Jan 1, 1891

By N. W. Lord

The process of molten-zone refining is analyzed for long ingots and many zone passages. Formulas are derived which give the resultant impurity distribution in terms of finite series. A comparison with the approximate procedure of Hamming is given. HE physical principles and applications of an extremely physicalprinciple efficient form of metallurgical refinement has been described by Pfann. The purpose of the present paper is to describe a method of analyzing exactly the particular program used which enables the segregation effect to be predicted for any number of molten-zone passages in a long ingot. The method is applied to the particular case of refinement of an ingot whose impurity initially is uniformly distributed throughout its length. A number of molten zones of equal length are passed through the ingot effecting a radical redistribution of impurity. Pfann has indicated an approximate method, due to R. W. Hamming, of calculating the resultant concentration after each successive zone pass for a particular value of the segregation constant defined in his paper. Here a solution will be presented in terms of the number of zone passes and the segregation constant. The expression, though cumbersome, is exact and susceptible to ordinary numerical computation procedures. The results of a similar computation using the procedure of Hamming are presented in a table together with the exact results of the present method. The discrepancy in terms of absolute concentrations is tabulated for the first eight zone-lengths. To establish the notation (which follows that of Pfann1 as closely as possible) and physical basis of the analytical equations, the physical model and principal assumptions may be reviewed. An alloy of two elements, where there is formed a continuous range of solid solutions, usually does not melt as a simple compound. Rather, a temperature is reached where the solid solution is in heterogeneous phase equilibrium with a liquid solution of different composition. The temperature dependence of these equilibrium compositions forms part of the phase diagram. For very small concentrations of a solute B in a solvent A, this usually takes the form of Fig. 1. Sometimes the solidus and liquidus slope upward. This corresponds to a segregation constant (defined below) which is greater than unity. The segregation constant is now defined as k = Cn(x)/CnI(x) [1] where C,,(x) is the impurity concentration in the solid ingot at distance x during the nth passing of a molten zone and Cnl (x) is the impurity concentration of the liquid zone from which the solid at dis- tance x is formed (see Fig. 4 of ref. 1.) C (x) remains the same after passage of the zone. The constant k may be either greater or less than unity in general. Purification in the former case is effected only in a finite ingot and in the portion that is melted last. For k less than unity purification is effected even in an infinite ingot. The method which follows gives, in the former case, the successive increases in impurity concentration and, in the latter case, the successive decreases in concentration. The general case of impurity redistribution will be considered first, and purification will be discussed later on. The analysis rests on the following assumption: The movement of the zone is too rapid to allow appreciable atomic rearrangement in the solid sections and too slow to disturb the uniform impurity distribution in the liquid zone characteristic of equilibrium. Hence, the composition in the solid at the left solidifying interface will be determined by Eq. 1 while the impurity concentration of the liquid zone will be uniform throughout its length. The reasoning which follows closely parallels that of Appendix 11 in Pfann&apos;s paper. It is reviewed here for the case of the nth zone pass in order to make clear the meaning of an operator essential to the present method. Fig. 4 of ref. 1 shows the movement of a molten zone of length 1 in an ingot of total length d. Each Cn(x) can be determined from the condition that the amount of solute added to the zone during an incremental advance, dx, is due to the melting in of a solid portion C(x)dx and the freezing out of kCnl(x), that is d I —r- CnL (x) dx = Cn-1 (x+l)- kCnL (x) dx or, in terms of Cn(x) d k k —— C,(x) +—c.(x) =— Cn-1 (x + l). [2] dx l l This, of course, is derived from the main assumption, the fact that 1 is constant, and that the total impurity content previously present up to x + 1 is constant . A correction has to be made for the region (d — nl) < x < d. This is due to the zone length changing during the passage of the solidifying interface beyond x = d — 1. Since the general solution would be too complicated otherwise, only the region 0 < x < d — nl is considered. The general solution of Eq. 2 is

Jan 1, 1954

By J. F. Ednie

SCRAP metals to the value of more than a billion and a half dollars were recovered in the United States in 1939 for further use in industry. Few people have any true conception of the magnitude of the secondary-metal industry as related to that engaged in the production of the primary, or virgin, metals; of its importance, particularly when a shortage of primary metals exists, as at present; or of the advance that has been made in standardizing and improving the quality of its products. Of the iron and steel produced in the United States in 1939 (the data used in this article are largely taken from Bureau of Mines reports for that year) just over 50 per cent came from scrap and slightly less than 50 per cent from ore. Of the principal nonferrous metals-aluminum, anti-mony, copper, lead, nickel, tin, and zinc-63 per cent came from domestic ores and 37 per cent from scrap. Fig. 1 presents graphically the relative tonnage and value of primary and secondary production of ferrous and nonferrous metals. In this chart only purchased secondary metals are considered, the figures being exclusive of "home" or "plant" scrap which amounts to rather large figures in the iron and steel industry. Incidentally, the chart shows that from the tonnage standpoint the iron and steel industry is some twenty times larger than the nonferrous industry, though with regard to the value of the product the ratio drops to about two to one.

Jan 1, 1941

Engineers who are in charge of industrial operations, and their number is legion, sense as much as anyone the present feeling of unrest in the&apos; country and more than anyone else realize the present inefficiency of labor. Undoubtedly the two phenomena are closely correlated and no doubt are due to a multitude of causes which it will be impossible to enumerate. From my experience in mining I estimate that the present efficiency of labor is only about two-thirds of what it was under pre-war conditions. In the mining industry, at least, we have not a large surplus of men looking for work and usually under these conditions men are rather more independent and will not work as efficiently and faithfully as if they felt there were plenty of men ready to take their places. Wages in metal mining have advanced more than the increased cost of normal and sane living. The result is that the men often work fewer days in a month and do not seem to have very much interest in their work while actually engaged in it. Then again, they have been listening to the more or less vague propaganda of the I. W. W. and the radical wing of the socialists, who are harping on the fact that the distribution of newly created wealth is unfair and that the laborer really is not working for himself or his fellow laborers but is carrying on his exertions for the benefit of a small and lim-ited class of exploiters. A continued harping on this view is bound to influence the judgment of even a conservative workman who is not a student of economics and who hears little or nothing upon the other side. I am a great believer in the common sense of the American people and in the long run I do not think that they will be carried away by unsafe doctrines. The trouble with so many of these propagandists of industrial in-equality is that they do not differentiate between production and dis-tribution. Even if we admit that distribution is unfair, unless goods are produced there will be nothing to distribute. A great many unthinking people seem to feel that wages are paid out of a pot which is inexhaustible and do not realize that eventually what comes out of the pot can never exceed what is put into it. The workman is not paid in money but is paid in goods, money as we all know being used simply as a measure of value and a medium of exchange, and that all that can be used to pay the laborer is what he produces.

Jan 11, 1919

By C. Fairhurst, A. M. Starfield

As a practicing mining engineer, I face many rock mechanics&apos; problems daily and would like to mention one or two examples to illustrate the current gap between laboratory investigations and actual field problems. I would like to endorse Dr. Obert&apos;s suggestion that more field measurements and observations should be undertaken. There is an ever-increasing body of data beginning with Hast&apos;s results in Sweden,l then measurements at Elliot Lake, Canada, and so on, including our own measurements at White Pine, which clearly indicate that the horizontal stresses underground are often at least as large as the vertical stresses. Visual obsenation of the deformation of roof and pillars (including failure due to horizontal compression) also demonstrates that the horizontal stresses are often most important. Yet almost every laboratory investigation begins with the assumption that the only stresses acting are vertical. Roof spans in layered formations. for example, are calculated on the assumption that the rock behaves as a gravity loaded beam. This is all too often unrealistic. Roof bolts are also often considered to be simply means of suspending the gravity loaded beams. As Dr. Reed has mentioned they are probably, in fact, acting to restrain a beam which is attempting to buckle due to lateral pressure. The fact that moisture can reduce the strengths of some rocks as much as 50 percent has been known for many years. In the mine me are almost always faced with wet rock, yet no one has investigated ways in which this wakening effect can be overcome. as, for example, by waterproofing the rock. C. Fairhurst, University of Minnesota I would like to mention that we have found,2 from stress-relief determinations, that appreciable (over 1000 lb per sq in.) horizontal pressures occur also at the surface in granites quarried in central Minnesota. Whilst I agree that more field measurements are desirable, it is important to point out that most university research is undertaken by graduate students who must attend classes daily. Their research is therefore restricted to the laboratory. A.M. Starfield, University of Minnesota No one denies the importance of obtaining: data from field measurements. It is equally important, however, that field measurements be guided by theory. Much time and money can be wasted by indiscriminate measurement. An example of the value of theory in interpreting measurements is given in Dr. Obert&apos;s comments on the time dependent strain observed in a salt mine. He anticipated that the stress at the wall of the opening would change with time because salt is viscoelastic rather than elastic. It can be shown from theory that if an excavation in a viscoelastic medium is unsupported, then the stress at the wall does

Jan 1, 1967

By Herbert H. Kellogg

C. M. Decroly (University of Brussels, Belgium) — The importance of the fluorides in the process metallurgy of special metals has already been accepted and it will probably increase in the future. Free energy diagrams as such established by Professor Kellogg are therefore very useful. It is interesting to note that the absolute value of the standard free energy of formation of HF increases with temperature, whereas for almost all the other fluorides it decreases; consequently it should be theoretically possible to reduce all the fluorides of the metals which, at low temperature, have a greater affinity for fluorine than hydrogen by this last element, provided a sufficiently high temperature is used in order to have a good efficiency. However, with regard to the reduction of UFe by hydrogen, I doubt that it will be possible to obtain directly the metal at comparatively low temperatures. There are other uranium fluorides which are more stable than UF6 and it is very likely that such fluorides will be obtained first. For example, in considering the reaction: UF6gas + H2gas + UF1so1id + 2 HFgas it is found, using the thermodynamic data of Brewer et al, that ?H298 = —66 kcal and ?G°298, = —65.2 kcal. As a result, the reduction of UF6 to UF4solld should proceed spontaneously even at ordinary temperature. On the other hand, the standard free energy of formation of UF4solid at 298°K is AG°298 = -209 kcal per mol of F2. The reduction of UF4 by hydrogen will be practically difficult and, as it is known, the only practical way of reducing this compound is to use alkaline-earth metals such as calcium or magnesium. I should like to point out, further, that the fluorination of many metal oxides can be carried out very easily by using the ammonium difluoride method of preparation, which renders the use of fluoride gas unnecessary. The first compound formed is generally a double fluoride of the metal and ammonium. This compound can be decomposed by heating either in a vacuum or in an inert atmosphere, ammonium fluoride being volatilized leaving the metal fluoride in a very pure state. H. H. Kellogg (author&apos;s reply)—Professor Decroly is quite right in pointing out that the formation of lower halides of uranium may complicate the reduction of UF6 by H2. I was unable to find his reference to the free energy of formation of UF4 in the compilation of Brewer.13 however. The value of AG°298, = —209 kcal for formation of ½ UFa seems rather high, and I hope the source of this value may be made clear.

Jan 1, 1952