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By R. S. Shrode

By now most readers of this column are aware that it no longer has a regular editor. Tom Murphy, who did the job so well, has had to bow out because of his duties in Australia---duties that keep him from the luxuries of such things as typists and typewriters for rather extended periods of time. We will miss his regular contributions but hope and expect to hear from him as a guest columnist from time to time. Finding an editor to function on a regular basis turns out to be no simple task. This does not mean that there may not be candidates around who would secretly enjoy having their arm twisted into a "yes" position, but at the moment none has been found. Anyway, at the Salt Lake City business meeting it was agreed that we should try to spread the load around. To that end, the Regional Vice Chairmen were specifically singled out as one potential source of contributions. These fellows should have an opportunity for a hearing during their term in office. The existing organizational set-up of the IndMD Division may be a little unfair to this group of officers. The limited responsibility outlined in our Manual of Official Duties and Responsibilities does not offer them much chance for self-expression. Probably the by-laws were written so as to have a geographic representation of membership in case it should be needed at some time. But that is another subject. The point is that now these regional officers have an opportunity to speak out on topics of their own choosing through this column. Some have already done just that. There are also other potential contributors to the column. One is the Secretary, who twice a year uses the column for distributing the minutes of our business meeting to the members. Another is the outgoing Division Chairman. In Salt Lake City, it was decided that this officer should be challenged to contribute something each year as a means of reviewing events of the past year or explaining what should have happened but didn't. I am, therefore, trying to accept that challenge.

Jan 1, 1970

By H. L. Washburn, G. L. Judy

DURING recent years thermal drying of fine coal has increased at a tremendous rate, but very little discussion of the several excellent units has found its way into print. This is particularly true for operating and maintenance costs, and the operator who is faced with his first fine coal drying installation must depend chiefly on hearsay when trying to determine what his drying costs will be. This article presents the maintenance and operating costs for the seven drying units now installed in preparation plants of Pittsburgh Consolidation Coal Co. and lists other cost information that should be obtained before any particular drying unit is selected. Plant Description: The fine coal drying section of Plant A consists of four Flash driers operating on two furnaces equipped with spreader stokers. Plant B has one Flash drier operating (together with a screen-type coarse coal drier) on one furnace equipped with a spreader stoker. Plant C has two Cascade-type driers operating on a single furnace with a spreader stoker. Plant Costs: Tables I, 11, and III present the cost of operating these units as reported by the individ- ual plants. As can be seen, the labor rates vary, depending on the amount of overtime paid and the time interval the cost figures cover. There is considerable variation in thermal units used and in the value given to the thermal units at the particular mine. There is some difference in power costs at a given location and, finally, the power costs of conveyors leading to the drying plants were included in some cases. Maintenance supply costs are simply a tabulation of the cost of all supplies used on the driers, furnaces, and stokers. Depreciation is not included, and the tables omit items such as supervision, plant cleanup, oiling, general maintenance, taxes, and insurance. These tables in themselves do not offer a true comparison of costs. This information must be reduced to some common basis. But what is this common basis to be? A mine operator must calculate his overall mine and preparation plant costs in terms of tons of clean coal sold. Unit costs on pieces of equipment within a given plant are correctly calculated on the same basis. However, when unit costs are compared between one plant and another, some thought must be given to unit design. This reasoning is similar to the old argument concerning i solid bowl vs basket-type centrifuges—the units themselves are not directly comparable without their supporting equipment. So it is with thermal driers. Except in rare cases of low entering moisture i content, driers are sized on the basis of water that must be evaporated, while the wear each unit gets de-

Jan 1, 1958

By H. F. Seifert

THE classification and preparation of non-ferrous scrap metals is a subject of interest to every individual and corporation that employs in its processes of manufacture non-ferrous metals and alloys and accumulates in such manufacture scrap from these materials for disposition in the form of turnings, borings, short ends, punchings, clippings, grindings, washings, etc. All too frequently the disposition of such scrap is left to individuals who have no knowledge of the subject either from a metallurgical or a commercial standpoint, or both. Much money is thus lost which with a little more intelligent effort might be saved, and in this day of fierce competition and small profits such an opportunity cannot be ignored. The Mineral Resources of the United States for the year 1925, the latest issue available (Part 1, page 221), gives the secondary non-ferrous TABLE 1.-Some Secondary Non-ferrous Metals Recovered in the United States for the Year 1924-25 Material Short Tons Value Copper, including that in alloys other than brass.... 250,600 $ 71,170,400 Brass, scrap remelted 242,300 56,270,800 Lead as metal 112,4201 39,477,100 Lead as alloys 112,460 Zinc as metal 61,430 11,359,000 Zinc -in alloys other than brass 13,300 Tin as metal 1 7,950 35,165,400 Tin in alloys 23,000 Antimony as metal 1 } 3;794,000 Antimony in alloys 10,839 Aluminum as metal 17,700 24 Aluminum in alloys 26,300 ,816,000 Nickel as metal 19 1 1,518,000 Nickel in non-ferrous alloys 2,109 Total 882,600 $243,570,700

Jan 1, 1928

The income of the Institute is derived from dues, subscriptions to MINING AND METALLURGY sale of publications. These sources are fortunately supplemented by the interest from invested funds now amounting to over $500,000, a considerable portion constituting endowments for especial purposes. Aside from the medal funds the principal endowments are the James Douglas Fund for support of the Library, the Rocky Mountain Fund and the Seeley W. Mudd Memorial Fund. The income from the two last named is available for the support of research and a variety of other purposes. It is allocated by the Board of Directors upon recommendation of standing. committees in each case. An active effort is being made to increase the endowments of the Institute, it being felt that unusual opportunities exist for research and public and professional service through the organization and at a minimum of expense. J. V. W. Reynders is chairman of the Endowment Committee.

Jan 1, 1929

By H. F. Seifert

THE classification and preparation of non-ferrous scrap metals is a subject of interest to every individual and corporation that employs in its processes of manufacture non-ferrous metals and alloys and accumulates in such manufacture scrap from these materials for disposition in the form .of turnings, borings, short ends, punchings, clippings, grindings, washings, etc. All too frequently the disposition-of such scrap is left to individuals who have no knowledge of the subject either from a metallurgical or a commercial standpoint, or both. Much money is thus lost which with a little more intelligent effort might be saved, and in this day of fierce competition and small profits such an opportunity cannot be ignored. The Mineral Resources of the United States for the year 1925, the latest issue available (Part 1, page 221), gives the secondary non-ferrous TABLE 1.-Some. Secondary Non-ferrous Metals Recovered in the United States for the -Year 1924-25 Material Short Tons Value Copper, including that in alloys other than brass.... 250,600 8 71,170,400 Brass, scrap remelted : 242,300 56,270,800 Lead as metal : 112,420 39,477,100 Lead as alloys 112,460 Zinc as metal 61,430 11,359,000 Zinc in alloys other than brass 13,300 Tin as metal 7,950 Tin in alloys 23,000, 35,165,400 Antimony as metal 1 3,794,000 Antimony in alloys : 10,839 Aluminum as metal 17,700 24,816,000 Aluminum in alloys 26,300 Nickel as metal 191 1,518,000 Nickel in non-ferrous alloys 2,109 Total l 882,600 $243,570,700

Jan 1, 1928

By Henry Knox

AMIDST the tumult and the shouting of the times, there are perceptible certain tendencies, quiet though serious, to take stock of the situation with a view to putting our house in order, and of these none is more encouraging than the awakening, interest in the higher education, and especially in technical education. Various committees of the professional organizations have cast much light on the matter and have pointed the way to progress and reform, but their scope is necessarily restricted by the requirements of precision and any excursion beyond these bounds must be undertaken by the unfettered individual who is free to rush in where responsible committees fear to tread. A discussion of the bearing of the higher education on character scarcely lends itself to objective treatment and yet, fraught as it is with imponderables and abstractions, the theme cannot be escaped in any com-prehensive scheme of education. The question is being pressed with growing insist-ence, why these United States, relatively to Europe, are deficient in intellectual output, and the ready reply, "Because America is a new country and Americans are too intent on developing their natural resources," is too facile and too false to carry conviction.

Jan 12, 1922

By J. E. Drury, W. M. Byers, E. J. Lynch

Measurements made with starch ~~~~s indicate that the Presence of starch serves to depress the streaming potential of a clay mud system. Measurements with pure starch slurries show that the addition of NaCl or CaO reduces the streaming potential significantly. The addition of NaOH, however, causes only a minor reduction in potential even when there are large changes in mud resistivity. INTRODUCTION In their excellent study of the streaming potential, Hill and Anderson' proposed that the presence of conductive solids within the filter medium will reduce the generated potential. This theory was demonstrated with measurements on shaly sandstone cores having various "b" factors; the cores with the higher negative b factors showed markedly lower potentials. (The factor b was originally defined by Hill and Milburn2 in an expression relating the resistivity of a shaly sandstone to the resistivity of the interstitial water: log F, = log F,, + b (log 100R,)'. 'he factor b, therefore, is a measure of the contribution of the conductive solids to the total conductivity of the sample. It has been found experimentally to be directly related to the amount of chemically exchangeable ion per unit pore volume.) In the logical extension of this hypothesis to the streaming potential created by filtration through mud cakes, they suggested that the presence of nonconductive starch in a drilling mud would have the opposite effect; i.e., it would cause the streaming POtential to be increased. The high streaming potentials that they observed with lime muds were attributed to this cause. A cross-plot of some of their results which are relevant to this discussion is given in Fig. 1. The lime-mud curves and untreated-mud curve are taken from curves given in their paper. The gyp-mud line was estimated from their statement that the measured streaming potential for gyp muds in the range of 1.5 to 2.0 ohm-m was approximately 18 mv/1,000 psi. These gyp-mud potentials were the lowest that they reported for any of the bentonitic-clay muds, and were the only ones which were less than the untreated-mud potentials. This very low streaming potential of gyp muds has also been observed in field studies.' By way of comparison, a U. of Texas publication4 gives the approxi-ate compositions for lime and gyp muds shown in Table 1. These materials are added to a bentonitic-clay mud base. It can be seen that both of these muds contain significant amounts of calcium salts and that the gyp mud has the higher concentration of starch. It would appear from this and from the data shown in Fig. 1 that starch may well be the cause of a streaming-potential reduction, rather than a potential increase. EXPERIMENTAL A series of streaming-potential experiments has been performed using a cell of a design similar to that reported by Wyllie.5 Calomel electrodes were used in both the mud slurry and the filtrate. Pressure in the cell was generated with high-pressure nitrogen. The primary objective of the investigation was to determine the effect of starch on the potential. Five different slurries were made which ranged in composition from untreated ben-tonitic mud (Baroid Aquagel) to a pure starch suspension (Baroid Im-permex). The intermediate slurries were prepared by mixing together a 9-lb/bbl clay mud with a 12-lb/bbl starch suspension in the ratios 1:3, 1:1 and 3:1. When starch was used alone, it was necessary to use an 18-Ib/bbl mixture, since leaner mixtures would not form a suitable filter cake. The clay mud used in the experiments was aged for three months before use. In addition to this series of measurements on the starch-clay mud mixtures, other experiments were performed to determine the effect on the potential of the absolute starch and Aquagel concentration, and the effect of adding various chemicals. RESULTS The effect of starch on the streaming potential is shown clcarly in Fig 2. Increasing percentages of starch resulted in n continually decreasing

By J. F. Myers, S. E. Sharp

The safety data presented in this paper are based upon replies to a Questionnaire sent out to representative mining companics. The authors feel that it is a fair cross section of the milling industry, in that the 17 companies, of the United States and Canada, reporting on 22 mills, are scattered from the Hudson Bay to the Mexican border and from coast to coast. These data concern the accident records of the various plants from 1939 to 1944, inclusive and the six years are divided into two periods. The first period (1939, 1940 and 1941) represents something of a normal operating condition. The second period (1942, 1943 and 1944) represents the period of time that was most affected by war conditions. During the second period there was a high labor turnover, inexperienced workers were numerous, women replaced men in many kinds of work, a labor shortage existed more or less throughout the industry, and supervision was pushed for peak production. All of the companies reporting compiled their accident experiences for these six years in accordance with the standards set up by the American Standards Association (New York, N. Y.), consequently the tabu lated data presented herein are comparable. The authors of this paper feel that the industry as a whole is greatly indebted to the personnel of the companies that furnished these data, which make this study possible for presentation. This survey covers a total exposure of 74,528,880 man-hours, with 105,471 man-days of lost time from 870 accidents. Safety Records In Table I, the safety record is shown of the various mills reporting. The severity rate is usually conceded to be the most vital statistical figure in safety parlance, therefore the participating companies are listed in order of their severity rate for the combined six-year period, under size of organizatiori. The table also shows the frequency rate as well as the frequency-severity ratio (F/S). As noted in Table I, most of the companies suffered an increase in both severity and frequency rates during the second period; only six of the 22 enjoyed an improvement. From correspondence with the various plants, it seems that a few had very little labor shortage or turnover, and these were not greatly affected. A few plants, anticipating the situation, strengthened their training facilities and actually were able to show a better experience during the second period. This gives great credence to the value of organized training in any safety program. The frequency-severity ratio (F/S) shown in the last column of Table I offers

Jan 1, 1947

By S. E. Sharp, J. F. Myers

The safety data presented in this paper are based upon replies to a Questionnaire sent out to representative mining companics. The authors feel that it is a fair cross section of the milling industry, in that the 17 companies, of the United States and Canada, reporting on 22 mills, are scattered from the Hudson Bay to the Mexican border and from coast to coast. These data concern the accident records of the various plants from 1939 to 1944, inclusive and the six years are divided into two periods. The first period (1939, 1940 and 1941) represents something of a normal operating condition. The second period (1942, 1943 and 1944) represents the period of time that was most affected by war conditions. During the second period there was a high labor turnover, inexperienced workers were numerous, women replaced men in many kinds of work, a labor shortage existed more or less throughout the industry, and supervision was pushed for peak production. All of the companies reporting compiled their accident experiences for these six years in accordance with the standards set up by the American Standards Association (New York, N. Y.), consequently the tabu lated data presented herein are comparable. The authors of this paper feel that the industry as a whole is greatly indebted to the personnel of the companies that furnished these data, which make this study possible for presentation. This survey covers a total exposure of 74,528,880 man-hours, with 105,471 man-days of lost time from 870 accidents. Safety Records In Table I, the safety record is shown of the various mills reporting. The severity rate is usually conceded to be the most vital statistical figure in safety parlance, therefore the participating companies are listed in order of their severity rate for the combined six-year period, under size of organizatiori. The table also shows the frequency rate as well as the frequency-severity ratio (F/S). As noted in Table I, most of the companies suffered an increase in both severity and frequency rates during the second period; only six of the 22 enjoyed an improvement. From correspondence with the various plants, it seems that a few had very little labor shortage or turnover, and these were not greatly affected. A few plants, anticipating the situation, strengthened their training facilities and actually were able to show a better experience during the second period. This gives great credence to the value of organized training in any safety program. The frequency-severity ratio (F/S) shown in the last column of Table I offers

Jan 1, 1947

By W. C. Dickerman, J. F. Thornton

TOTAL global war is making extraordinary demands on the oil industry. Huge quantities of 100-octane gasoline, extreme service lubes, toluene and other miscellaneous products are required. 100-octane gasoline is blended from isopentane, base stock, and alkylate. Isopentane is fractionated from natural or refinery gasoline; but since only limited quantities of base stock can be made in this way, catalytic cracking is rapidly becoming the major source of base stock. Alkylate, the most important component, is synthesized from isobutane and an olefin. Extraordinary demands are forcing the full utilization of all present sources and the development of new supplies of feed stocks. Fortunately, the United States finds itself with well-developed processes already available, and this is true of the manufacture of lubricating oil as well. Toluene is now being produced by new methods from special cuts fractionated from selected crudes or from catalytically processed naphthas. Designers of refinery equipment are modifying past practices to conserve every bit of material possible.

Jan 1, 1942

By W. A. Olds, H. F. Yancey, M. R. Greer

John Griffen (Consulting Engineer, Pittsburgh)— This paper presents much data offering tentative answers to many technical questions that have been raised by the employment of dense-medium processes and, particularly. by use of the drum-type vessel. It is to be hoped that the Bureau of Mines will publish complete detailed data for the 50 or more tests so that it may be studied and analyzed by everyone interested. Such study will take considerable time and effort. The writer is therefore obliged to confine his discussion to a few points he has noted as being open to question. The data in Table VI which shows the recovery efficiency for the 1 to ½-in. fraction as 100 pct raised a question concerning the accuracy of these calculated figures; washability data on the washed coal and refuse show that such a figure is impossible. When the ash content of the misplaced material in the washed coal is higher than that of the misplaced material in the refuse, recovery efficiency must be less than 100 pct. A etudy of the data In Tables 111, IV, V, and VI suggest that this error probably arose from slight errors in calculating the data in Table V and more probably from the small scale used in plotting the washability curves from the Table V data. Using the size consist data and the weight and ash percentages of individual gravity fractions of each size as given in Tables 111 and IV and the reported recovery of 80 pct of washed coal, a revised Table V was calculated, carrying weight and ash percentages to hundredths of a percent instead of rounding off at tenths. This washability data for each size of Belling-ham reconstituted feed was then plotted on large scale washability curves. From this data the new Table XIV was prepared, which agrees very closely with data shown in Table VI except for two important values, theoretical yields and recovery efficiencies. As will be noted the recovery efficiencies in Table XIV are significantly lower than those given in Table VI. A study was then made of the data showing distribution of the specific gravity fractions to washed coal and refuse. This study indicated that when this distribution was based on the fractions as tested at 0.1-sp gr intervals the number of points obtained were insufficient to establish the distribution curves with reasonable precision, which in turn would affect the accuracy of the values for the specific gravity of separation and the error areas. The data in Tables III and IV of the paper and curves prepared therefrom make it possible for the specific gravity fractions to be subdivided further. This was done using 0.05-sp gr fractions and the distribution data so obtained is given in Table XIV, with resulting values for the specific gravity of separation and the error areas. The writer believes that the derived values shown on Table XIV are more accurate than the correspond-

Jan 1, 1955

By R. A. Greenkorn

This project originated in a practical problem—we needed five tracers that could be used together to locate flow paths in a pilot flood. While tracers for subsurface liquids have been used since the turn of the century,1-15 none of those reported in the literature appeared to be either consistent or quantitative enough for our purposes. Most were used in field systems without controlled experiments to determine the accuracy and precision of analysis, and many were tracers that could not be used collectively. The ideal tracer, of course, would follow the fiuid of interest exactly, traveling at the same velocity as the fluid front. But the ideal is impractical to attain because adsorption-desorption effects cause the tracer to lag behind the front; these effects, plus diffusion-dispersion effects, cause the tracer front to spread more than the fluid front. Thus, our objective was not to locate a tracer that would be ideal for all circumstances but rather, to find one that would approximately follow the fluid, or one that under controlled conditions could be corrected to calculate the movement of the fluid front. We considered tracers satisfactory—(1) if they were easy to analyze; (2) if their breakthrough-elution curves were not too different from those for the chloride ion, a tracer believed to follow the fluid front closely; and (3) if we could calculate from the curves a material balance, at 1.25-PV (pore volume) injected, within 5 per cent of that calculated from chloride curves. Of a possible 35 materials, we selected 13 tracers that could be quickly and easily identified and whose analysis was claimed to be accurate within 5 per cent. Only one of these, tritiated water, was a radioactive tracer. Radioactive tracers are easy to detect even in small quantities, but they require special handling and special equipment. Also, those that can be used together are limited because special equipment is required to separate emissions from the various tracers. Two of the original 13 tracers were eliminated in static tests to determine how accurately and precisely they could be analyzed, and to check on gross adsorption. The remaining 11 were flowed through a 9-ft linear sandstone model, and breakthrough-elution curves were obtained. Finally, three tracers were field-tested as breakthrough tracers. These tests are described in the following sections. The 13 tracers considered in these experiments were EDTA (ethylene diamine tetra acetic acid), fluo-rescein, picric acid, salicylic acid and ammonium, boron (as borate), bromide, dichromate, iodide, nitrate and thiocyanate ions, plus chloride ion and tritiated water. All but the chloride ion and tritiated water were subjected to static sand tests to eliminate the tracers that could not be analyzed quickly and accurately and to eliminate those that showed excessive adsorption. All but two of the tracers, EDTA and salicylic acid, qualified for flow tests on this basis. The procedures used in the static tests (see Appendix A for analytical details) were as follows. Each tracer (in the amount shown in Table 1) was dissolved in 1,000 ml of water. Then, 800 ml of this solution was added to 500 gm of sand, and the remaining 200 ml was reserved as a control standard. The sand-tracer mixture was agitated once a day over a 10-week period, and during this period we analyzed five duplicate samples from this mixture, along with five duplicate samples from the control solution. From the control-sample analyses, we constructed a control chart on which the sand-tracer analysis results were plotted. The control chart, and its use to determine accuracy and precision of analytical results, as well as the amount of adsorption, is described in Appendix B. The results of the static tests are summarized in Table 1, which lists the concentration c (concentration at time t) divided by c, (initial concentration). If there was no adsorption, c/c, = 1. The acceptable deviation from this value varied from tracer to tracer, depending upon the limits of analytical precision established for the different tracers. The best results were obtained with boron, bromide and dichromate, with all values falling within limits of accuracy and precision. Ammonium, iodide, nitrate and picric acid also were satisfactory, although the ammonium results were erratic. Flourescein and thiocyanate were unsatisfactory ini-

By M. W. Dumais, E. P. Abrahamson

In a paper by Abrahamson and Alexander concerning a series of correlations between electronic structure and property changes, it was hypothesized that each solute atom in a dilute solution had a characteristic volume of solvent atoms over which some form of electronic interaction occurred. From this description it is possible to picture the solute atoms as occurring in an ordered array for the most efficient arrangement. A recent review article2 has shown that some form of anomaly exists for a whole series of properties when dilute additions of tungsten are made to iron, of. Fig. 1. Any mechanism to fit one property must also be amenable to mechanisms for the other properties. The possibility of some structural change in this region appears to offer the best hope. The system chosen for investigation was the iron tungsten system. Zone-refined iron with zone-leveled tungsten additions were supplied by Materials Research Corp. as 3/8-in.-diam bars. Transmission electron microscopy was used to study the structure. One-quarter inch specimens of each alloy were cold-rolled to 10-mil sheets, cleaned, punched to electron-microscope specimen-holder size, and annealed in vacuum for 2 hr at 800°C and 2 hr at 700°C followed by a furnace cool. The specimens were attached to a platinum wire and the specimen edge and wire were painted prior to thinning in a solution of 10 pct perchloric acid in glacial acetic acid. It was believed that if ordering were present due to electronic interactions the polishing procedure chosen would provide a simultaneous combination of chemical attack and electropolishing to exhibit the ordered structure. The chemical attack would be expected to penetrate those areas equidistant from the tungsten atoms, while the electropolishing would serve to "plane off" the volumes where the chemical attack had taken place. If one of the ordered tungsten planes were parallel to the specimen face at the edge of the thinned hole, a plate or micalike structure would be expected. A typical result of this polishing is shown in Fig. 2. Here a series of plates can be seen lying one upon the other. In several other specimens the plates parallel to the electron beam have been observed, behaving like slices of bread in a loaf. These edge views coupled with moire patterns indicate that the minimum plate thickness is 37 to 42A. This is equivalent to a concentration of 455 at. ppm of W if a simple cubic superlat-tice exists, or one tungsten atom every twelve iron atoms on the ordered plane. It was further noted that the base iron exhibited no signs of platelike structure. As the concentrations increased above 100 at. ppm W the amount of plate material increased. Among the specimens investigated was that shown

Jan 1, 1967

By D. H. Turner, F. A. Crossley

The titanium-rich corner of the system Ti-Al-Si has been studied to determine the phase relationships in the temperature interval 600° to 1200°C. Metallographic examination of long time isothermally annealed specimens was the means of investigation. PART of a program on phase relations and transformation processes of titanium alloy systems included the study of the titanium-rich corner of the Ti-Al-Si system. The investigation covered ternary compositions in the range 2 to 8 pet A1 and 0.1 to 2 pet Si and binary compositions in the range 0.2 to 2 pet Si. Temperatures were in the range of 600" to 1200°C. Alloys containing 6 pet A1-0.1 to 0.5 pet Si were investigated down to 400°C. Partial vertical sections are presented for 2, 4, 6, and 8 pet Al. The Ti-Si system has been reported by Hansen et al.' It is characterized by a eutectoid decomposition, ß = ± a + Ti3Si3, at 860°C. The maximum solubility of silicon in a is reported to be about 0.5 pet at the eutectoid temperature. The solubility of silicon in 0 increases from 0.9 pet at the eutectoid temperature to approximately 3 pet at the eutectic temperature, 1330°C. Several investigations in the composition range of interest have been reported for the Ti-A1 system."' These investigations are in agreement on the phase fields, but differ to small extents on boundary positions. However, very recent, and as yet unpublished, findings" " indicate that there are perhaps two phases which occur at lower aluminum contents than the ? (TiA1) phase, and that the solubility of aluminum in a titanium is less than 6 pet. In the present investigation phase relations found are in agreement with the published literature exemplified by the work of Bumps et al.3 Therefore, it is probable that the partial system reported herein is metastable and does not represent true equilibrium. Experimental Procedure High purity Bureau of Mines titanium sponge of 103 Bhn hardness, granulated aluminum shot of 99.7 pet purity, and silicon powder of 99.8 pet purity were used in making the alloys. For the work in the range from 600" to 1200°C, 100 g ingots were prepared by arc melting. Melting losses were negligible and spot checks by chemical analysis showed good agreement between nominal and analyzed results. Nominal compositions are used throughout this paper. Ingots were forged to 3/8 in. rounds and cut into specimens for heat treatment. Isothermal anneals in the range from 600" to 900°C were preceded by solution treatment at 1000°C for 1 hr, followed by furnace cooling to the annealing temperature. Samples were sealed in evacuated Vycor bulbs for heat treatments up to 1000°C. Higher temperature anneals were done with the samples sealed in quartz bulbs under a partial pressure of argon.

Jan 1, 1959

By R. L. Huntington, D. T. MacRoberts, Charles R. Hetherington

Since the equation of continuity governing transient flow of gases through porous media cannot be integrated mathematically into a simple usable expression free from series terms, empirical and approximate equations have been advanced relating cumulative production and future production rates from gas reservoirs with time. In order to check the accuracy of these empirical equations and to obtain an insight into the initial conditions pertinent to the solution of the fundamental equation of continuity, experimental work has been conducted on a vertical 2-in. tube, 91.6 ft. high, packed with unconsolidated Wilcox sand. The results presented in graphical form show the accuracy of the approximate relations. Data from unsteady-flow runs on the 2-in. experimental tube are presented graphically, and are applied to obtain an equation for this specific case, and are offered as an aid in future investigations of this basic equation. The close agreement between equations calculated for steady-state flow and the experiments indicates that the decline of actual gas reservoirs may be treated by an application of these equations without serious error. Introduction The steady-state flow of gas through a porous material—that is, flow wherein the boundary conditions do not vary with time—is subject to analytical solution. Muskat1 has shown that the general differential equation is simply the La Place equation in P2. Direct solutions may be at once obtained. The unsteady state, on the other hand, is not analytically reducible. Since nearly all phenomena of practical interest in gas production involve flow in the unsteady rather than in the steady state, it has been necessary to derive approximate Solutions to the general equation. The validity of such approximations has not hitherto been adequately tested. In the experiments to be described a simple, closed, linear system is substituted for the real complex gas field. The general results, however, are independent of the geometry Of the system' The problem studied is the rate of production, and the accompanying variations in pressure, when one end of a linear porous system is opened to the atmosphere and permitted to produce to exhaustion. An approximate solution to the general differential equation, based upon the assumption of an "infinite series of steady states," is then applied to the results to determine the validity of this method of dealing with actual reservoirs. Theoretical Considerations The fundamental differential equation governing the flow of a gas through a Porous medium can be derived easily from the equation of continuity, Darcy's law, Boyle's law and a statement of the thermo-dynamic nature of the flow. For isothermal flow it is: d2P2/dx2 + d2p2/dy2 + d2p2/dz2 = 2fµ/K dP-dT

Jan 1, 1942

By R. L. Huntington, D. T. MacRoberts, Charles R. Hetherington

Since the equation of continuity governing transient flow of gases through porous media cannot be integrated mathematically into a simple usable expression free from series terms, empirical and approximate equations have been advanced relating cumulative production and future production rates from gas reservoirs with time. In order to check the accuracy of these empirical equations and to obtain an insight into the initial conditions pertinent to the solution of the fundamental equation of continuity, experimental work has been conducted on a vertical 2-in. tube, 91.6 ft. high, packed with unconsolidated Wilcox sand. The results presented in graphical form show the accuracy of the approximate relations. Data from unsteady-flow runs on the 2-in. experimental tube are presented graphically, and are applied to obtain an equation for this specific case, and are offered as an aid in future investigations of this basic equation. The close agreement between equations calculated for steady-state flow and the experiments indicates that the decline of actual gas reservoirs may be treated by an application of these equations without serious error. Introduction The steady-state flow of gas through a porous material—that is, flow wherein the boundary conditions do not vary with time—is subject to analytical solution. Muskat1 has shown that the general differential equation is simply the La Place equation in P2. Direct solutions may be at once obtained. The unsteady state, on the other hand, is not analytically reducible. Since nearly all phenomena of practical interest in gas production involve flow in the unsteady rather than in the steady state, it has been necessary to derive approximate Solutions to the general equation. The validity of such approximations has not hitherto been adequately tested. In the experiments to be described a simple, closed, linear system is substituted for the real complex gas field. The general results, however, are independent of the geometry Of the system' The problem studied is the rate of production, and the accompanying variations in pressure, when one end of a linear porous system is opened to the atmosphere and permitted to produce to exhaustion. An approximate solution to the general differential equation, based upon the assumption of an "infinite series of steady states," is then applied to the results to determine the validity of this method of dealing with actual reservoirs. Theoretical Considerations The fundamental differential equation governing the flow of a gas through a Porous medium can be derived easily from the equation of continuity, Darcy's law, Boyle's law and a statement of the thermo-dynamic nature of the flow. For isothermal flow it is: d2P2/dx2 + d2p2/dy2 + d2p2/dz2 = 2fµ/K dP-dT

Jan 1, 1942

By Cecil Desch

THIS annual lecture, under the auspices of the Institute of Metals Division, and which was illus- trated by lantern slides, has been printed in full and a limited number are available for distribution on request. Some excerpts from the lecture are given below: Ever since the simple geometrical relations of crystals were discovered, it has been recognized that their proper-ties are best explained by assuming that their ultimate particles are arranged on a space lattice, and that the char-acteristics of that lattice determine the shape of the crystal and its physical and mechanical properties. Modern ex-amination by means of X-rays has widened that concep-tion and given it greater; definiteness, and the atoms are now regarded as the particles forming the space lattice. The splendid achievements of investigators in this field have made it possible to state, for a large number of sub-stances, the form and dimensions of the lattice. The char-acteristic of a lattice is that a unit of simple geometrical form is repeated at regular intervals in three dimensions so as to fill the entire crystal. It follows that there must be certain planes in which the atoms are more closely packed than in planes drawn at any angle to them, and it is these planes of closest packing which play the greatest part in determining the growth and other properties of the crystal. There are actually two stages in crystallization, what-ever be the medium in which it occurs. The first is the ap-pearance of crystal nuclei; the second the growth of those nuclei to form crystals of appreciable .size. The first is clearly a kinetic phenomenon. In the molten mass, solu-tion, or vapor, the molecules are in a state of rapid motion and frequent collision. When the temperature has fallen so far. that it is possible for a crystal to exist, a few col-liding molecules may fail to rebound, and so become at-tached to one another, the balance between the attracting and repelling forces-between them causing them to arrange themselves on a space lattice, to which other molecules sub-sequently attach themselves. It was once maintained that the X-ray evidence demanded that the molecule should dis-appear in the solid crystal, but this was a wrong inference, and in many crystals, but not in all, the chemical molecule retains its identity in the solid state. In pure metals the atom and the molecule are identical, so that the conditions are unusually simple. How many. nuclei will be formed in a given mass is evi-dently a problem in probability. Experiments to deter-mine the relation between the temperature and the number of nuclei formed in a given time have been made with some success by using viscous organic substances, but metals offer much greater difficulties, and the few determinations which have been published are vitiated by serious errors. However, the examination of sections of ingots of the same composition and cast at 'the same temperature in similar molds will show, that the number of crystals does not vary widely.

Jan 3, 1927

By Henry Fay

LAWRENCE ADDICKS, New York, N. Y., (communication to the Secretary *).-There are two points regarding gun erosion on which I want to say a few words: The first is about the analogy to hardening of wire by drawing and the second the possible role played by thermal conductivity of the metal. The ductile metals do not necessarily become brittle when cold-worked as it is possible to draw copper from 3. in. in diameter soft rod down to the finest hair wire without annealing. This results, as stated in the paper, informing a hardened core with a very hard skin. The electrical conductivity is depressed some 3 per cent. and the tensile strength nearly tripled. A soft copper wire 0.08 in. in diameter and 6 in. long may be twisted 150 or more turns before the wire will snap under torsion. A hard-drawn wire will break after perhaps a dozen twists, the skin breaking down at one spot. Just wiping the wire with a cloth clamp with dilute nitric acid has a remarkable effect in increasing the number of twists without appreciably lowering the tensile strength, showing the skin to be very thin. On the other hand, pickling the rod, from which the wire is to be drawn, in dilute nitric acid also greatly increases the number of twists which can be applied to the resulting wire. This indicates that the copper oxide scale produced when the wire bar is rolled hot is more or less rolled into the rod and may have much to do with the skin effect. We also know that if the conditions of drawing are not correct, the heat of deformation in the die may produce quite an annealing effect. The application of this analogy to what occurs in a gun to produce the effects noted offers some difficulty. The second point is that as the temperature of the surface of the gun bore has undoubtedly a great deal to do with the amount of erosion, one natural remedy would be to conduct the heat away fast enough to keep this temperature within desired limits. This brings up the question of the thermal conductivity of the metal of which the gun is made. We know that the conductivity of pure metals is greatly altered by alloying and that the alloy is usually, though not always, lower in conductivity than the metal before alloying. This is interesting when it is considered that the high-nickel and manganese-steel alloys show greater erosion as stated. Would it not be instructive to study the question from the point of view of heat conducted away from the eroded surface?

Jan 3, 1917

DETAILED programs for the Regional Meeting to be held at Boston, on Aug. 29, 30, 31, will be available on arrival at the Copley-Plaza Hotel, where registration will begin at 10 a. m. on Wednesday morning. The opening session will be non-technical in character and will be called to order at 11 a. m. Hector J. Hughes, Dean of the Graduate School of Engineering of Harvard University, and others will speak, and in the afternoon visits are to be made both to Harvard and Massachusetts Institute of Technology. Wednesday afternoon will be devoted mainly to the opening of an exhibit of geophysical instruments and methods at Tech. On the way back to the hotel a tour of Old Boston will permit the visitors to see many of the historic points of the city. A special meeting of the Board of Directors has been called to be preceded by the usual subscription dinner at the University Club at 6.30 p. m. Owing to limita-tions of room, invitations have been sent only to the usual list designated in the By-Laws, the Directors, past officers, chairmen of sections and of technical committees. The dinner and a brief business session of the Board will be followed by a technical session at the Copley-Plaza at 8 p. m. and this in turn by a buffet supper at the University Club at 10 p. m. Sep-arate entertainment is being provided for the women for the evening. Thursday will be devoted to technical sessions both in the morning and afternoon. If necessary to permit adequate discussion, an overflow session will be ar-ranged in the afternoon. In the evening, a subscription dinner will be given at the Copley-Plaza at which past-presidents John Hays Hammond and Robert H. Rich-ards will be guests of honor. It is promised that speeches will be short and dancing will be arranged for following. The women will be offered a luncheon and bridge party at one of the country clubs on Thursday, and Friday will be devoted to an all-day excursion for both men and, women. Members are asked to register promptly on arrival so that the various committees will know as early as possible for how many to provide. The major part of the technical program has been provided by the Committee on Geophysical Methods of Prospecting, and a series of papers of great value and interest in this new field has been brought together. Abstracts of substantially all of them are printed in this issue of MINING AND METALLURGY and the papers themselves will, with one or two exceptions, be avail-able in printed form at the meeting and later in the regular publications of the Institute.

Jan 9, 1928

By T. C. King

AT the new Graham-Central Mill of Eagle-Picher, near Galena, Ill., material is simultaneously dewatered and introduced into the ball-mill scoop boxes by the use of variable-speed, 24-in. spiral classifiers. This arrangement has proved satisfactory in that the moisture content of the wet feed is reduced, thus allowing maintenance of density within the mills, and a constant feed at any desired rate to the mills is provided. In this mill the primary feed is wet crushed to minus ½ in. and preconcentrated by jigs to produce a bulk lead-zinc-iron concentrate and a waste tailing. The jig concentrate is then dewatered by a conventional dewatering classifier and stored in, bins ahead of the ball mills. Even though this material is well dewatered, the discharge at the bin bottom is sloppy because of the gradual drainage of the water from the surface of the particles. Conventional belt feeders with vertical cutoff gates are unsatisfactory because of the flushing characteristic of the wet sand.

Jan 1, 1950