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By Cecil J. May

The importance of a knowledge of the physical laws involved in the production of oil from a reservoir has come to be generally realized in recent years and it is therefore unnecessary to elaborate on the many problems which still await complete solution. Among them the vertical flow of mixtures of oil and gas has attracted considerable attention and a number of papers have appeared in the literature from time to time. The complete solution of the problem would cover such aspects of oil-field technology as the calculation of bottom-hole pressures from purely surface data; the estimation of natural flowing lives; the design of gas-lifts and the selection of tubing for natural flow, and so on. It is still true, however, that the results so far published have not been particularly consistent and there are no generally accepted data available of universal applicability. It is, in fact, by no means easy to obtain a sufficiently wide range of variables under the operator's control to determine the laws of flow without ambiguity and much of the published research has been directed towards the solution of the specific problems of individual fields representing only a partial treatment of the whole subject. It was with a similar object that work was commenced on the Masjid-i-Sulairnan field of the Anglo-Persian Oil Co. towards the end of 1930 and has since continued as opportunity offered. Of course, the results obtained cannot necessarily be applied elsewhere without modification and, in some cases, considerable extension. At the same time conditions in this field are somewhat unusual in allowing certain aspects of the problem to be isolated and examined without the disturbing effects of a large number of independent or partially independent variables. For example, since the field is under unit control, it is possible to maintain steady conditions on any particular well over long periods. Moreover, the structure of the limestone reservoir is such that the gas-oil ratio for a given well is sensibly constant over very wide ranges of production rates, and in many cases the bottom-hole differential pres-

Jan 1, 1935

John Malcolm Fraser became Prime Minister in December 1975 when Australian voters gave him the biggest landslide victory in the history of the Federation. From the previous administration, Mr. Fraser has inherited an atrocious economic mess: a staggering budget deficit, an unrealistically overvalued currency, a 14% annual rate of inflation, mounting unemployment, and a demoralized business community. He has already tackled some of these problems with some measure of success; but he has been in power for barely a year, and it's too soon to see a turn-around.

Jan 1, 1977

By J. W. Eckerd

Anthracite mining developments have not been as spectacular as the advances made for bituminous coal. The reasons are well known, i.e., steeply pitching seams of the western, eastern, middle and southern fields, and the physical conditions of the strata in which the seams are situated. Beds with moderate pitches (30º to 35º or less) have been mined with coal planers, longwall with movable props, shaker chutes, coal borers and large diameter boring machines. However, the use of this equipment has been limited to a relatively small portion of the production. Long-hole drilling has been developed from a point where holes of 25 or 30 ft have been replaced by those up to 130 ft. This has been possible through the introduction of primacord and similar detonating agents that can fire a long train of explosives with one cap. The usual practice in long-hole mining is to drive a gangway, chutes and monkey heading, or return airway, in the normal development manner. Two breasts can then be driven from the lower to the upper level to act as openings for the beginning of the long-hole work. Following completion of the development, holes can then be drilled from the monkey headings 100 ft or more up the pitch through the coal to within 15 ft or more of the upper level, depending on the nature of the coal on the roof. The thickness of the coal bed determines the spacing of the long holes, although they usually are on 6-ft centers for a 6-ft thick coal seam. The Bureau of Mines has conducted extensive investigations and tests on the development of a hydraulic mining system to be used in conjunction with hydraulic hoisting. Tests were conducted in cooperation with a large anthracite producer in a coal seam from 10 ft 6 in. to 15 ft in thickness and on a pitch from 0º to 20. This particular mining procedure is adaptable only to thick seams on relatively flat pitch as the maneuverability of the hydraulic jumbo is an important restricting factor.

Jan 2, 1968

By Robert R. Boyd

The gravity discussed here is that of the clean oil produced. Gravities of fluids containing water, free or in the form of emulsion, sand, drilling mud or mineral salts of a nonbituminous nature do not represent the gravity of crude oil as considered in this paper. During recent years it has become a frequent occurrence for operators to be called upon to explain to landowners the reasons for variations in gravity on shipments of oil from wells in which they are interested as royalty owners. In regard to single well leases it has been noted that marked changes in gravity frequently have occurred for no apparent reason. Data collected on the subject and correlated with production methods reveal interesting facts. It is the purpose of this paper to present some of the highlights on the subject. These gravity changes in the natural crude oil are with a few exceptions the result of the liberation under varying conditions of the volatile hydrocarbons from the natural oil-gas solution contained within the pool. The subject of the liberation of gases from natural oil-gas solution has been investigated by Ben E. Lindsly, of the U. S. Bureau of Mines, and the observations recorded here are in the main consistent with his conclusions. Investigators have recognized two methods of liberation of gas from solution—flash and differential. In the latter method the vapors are removed from the liquid as rapidly as formed and have no opportunity to come to a condition of equilibrium with the oil. In flash liberation an equilibrium condition between the oil and the gas exists at the pressure of separation. Mr. Lindsly has found that the method of liberating the gas from the oil has a pronounced effect on the final gravity and that differential liberation results in a higher A.P.I. gravity due to the higher ratio of gasoline producing hydrocarbons left in the oil. Under actual production practices with high velocities in flow strings, it is our contention that conditions of perfect equilibrium between gas and the oil rarely exist, and that gas separation is made under varying conditions, sometimes approaching that of equilibrium and at other times departing from it.

Jan 1, 1937

By S. R. Elliott

THE principles of the caving system, as they apply to mining of soft iron-ore deposits, are well known, as this method has been in use for many years. It is, however, necessary to give a general description of it before describing the Athens method. The shaft and surface equipment should be placed at a sufficient distance from the orebody, so that the caving and pulling of the surface will not disturb the operations of the mine. Levels are started at the proper intervals, and when raises are completed, slicing commences at the top of the orebody and progresses downward. The necessary precautions are taken to avoid the occurrence of large open rooms and it is customary to break sufficient capping to form a mat to prevent heavy falls of ground from crushing through to the lower sublevels and endangering the lives of the workmen. Slicing is continued, and when sufficient width and length are undercut, the capping commences to cave, and in time a settlement occurs at the surface. As soon as this caving commences, the pressure on the timber naturally increases; after it extends to the surface, the amount of pressure has a certain relation to the depth. In other words, the pressure increases with the depth, but not in direct proportion. At great depths, such as that found at the Athens, 2500 ft. (760 m.), the pressure might be so excessive that the cost of keeping working places open would be prohibitive. The actual caving of the surface in a deep mine, with a great thickness of capping, is slow and often takes years to accomplish. After sufficient width and depth -have been undercut, the capping starts to break away, but through arching large masses of rock-.fill the opening, support the capping, and retard the continuation of caving. Caving to the surface is, therefore, retarded until either a sufficient thickness of the orebody is removed, or the width and length of the undercut part have been greatly increased. I wish to emphasize this fact of slow caving, for it is on, this principle that the success of the Athens system. largely depends.

Jan 8, 1920

By A. M. Gaudin

TEN years ago Taggart, Taylor and Ince1 described a workable, convenient apparatus for the measurement of contact angles be-tween cleaved, ground or polished particles and captive bubbles. Wark and Cox2 and Wark and Sutherland3 have done an im-mense amount of experimental work with this apparatus. Their work has had as principal object the determination of "con-tact curves." Contact curves are Cartesian charts in which pH (or some other variable) is plot-ted against quantity of modifying agent. The rectangular area is broken into two or more curvilinear areas separated by the contact curve. The curve indicates that a sharp demarcation exists between condi-tions that bring about sticking of particles to bubbles and conditions that do not pro-duce sticking, The type curve appears in the TRANSACTIONS as Fig. 1, page 248, volume 112. Wark and Cox offer data to show that the contact angle has a value determined by and characteristic of the agent used. Wark and Cox also make the statement that they believe this value is independent of concen-tration (ref. 2a, p. 209), They say: It is suspected that, given sufficient time and provided that there are no disturbing factors. the full ethyl xanthate angle (corresponding to a complete xanthate film) would be obtained in every case where contact occurs.

Jan 1, 1940

By W. R. Phibbs

The blast furnace of the Columbia Steel Corpn., at Ironton, Utah, was put in blast April 30, 1024, and its operation has presented some interesting problems. The coke for the furnace is furnished by 33 Koppers Becker type ovens of 15 tons capacity each. The coal is shipped from the company's mine at Columbia, Utah, which is approximately 123 miles from Ironton, and is probably the highest volatile coal that is being coked for blast furnace use in this country. The analysis of the coal is: PeR Cent. Moisture................................................. 3.90 Volatile.................................................. 39.00 Fixed carbon............................................ 51.10 Ash............................................... 6.00 Sulfur................................................. 1.07 The analysis of the coke is: PeR Cent. Volatile.................................................. 0.55 Fixed carbon............................................. 89.70 Ash...................................................... 9.75 Sulfur................................................... 1.05 The coke is light and of a fingery construction, but is very fast burning. A screen test of the coke as loaded into the skip tubs at the furnace shows the following: Per Cent. On 2 in.................................................. 17.90 On 11/2 in................................................ 41.78 On 1 in.................................................. 27.80 Through 1 in............................................. 12.52 The by-product yields are as follows: Gas................................. 11,000 cu. ft. per ton of coal Sulfate............................... 30 Ib. per ton of coal Tar.................................. 12.65 gal. per ton of coal Motor fuel........................... 3.00 gal. per ton of coal Average B. t. u. in gas................. 567

By John Hays Hammond

The following notes are descriptive of a country as yet in its infancy as regards the advancement made in mining operations. Its inaccessibility and other militating circumstances have retarded progress in that direction. With the completion of the railroad, now under construction, having the city of Cali as its objective point, with the concomitant civilizing and developing consequences, it is certain that the slopes of the Cordilleras will prove to be a South American Eldorado. Deposits of coal, copper, and minerals other than those of the precious metals are known to exist in quantities which, under more favorable conditions of accessibility, etc., could be profitably mined. The Government of the United States of Colombia, I think, is disposed to encourage and foster mining enterprises. Articles designed for mining are admitted free of duty; the permanency of the government is, at least, as well assured as that of Mexico (which is not noted for its immutability), and a more sincerely friendly sentitment towards Americans prevails in the United States of Colombia than in Mexico. This paper is confined to a description of the property of the Cauca company's mines, and is intended rather as a preliminary notice than as an exhaustive report. The Cauca mining district is reached by the following route: New York to Aspinwall; to Panama; to Buenaventura, a port on the west coast of the United States of Colombia, distant thirty-six hours from Panama by steamer; to Cali in the State of Cauca. The State of Cauca is bounded on the north by the Atlantic Ocean, on the northwest by the State of Panama, on the northeast by the States of Bolivar and Antioquia, on the east by Brazil and Venzuela, on the south by the Republic of Ecuador, and on the west by the Pacific. Ocean. It has a territory of 41,443 square miles, which is about one-tenth of the entire territory of the United States of Colombia. Its population, including the 50,000 savage Indians of the Caqueta (some of whom are cannibals), is nearly 450,000 souls, or about one-sixth of the population of the Colombian republic. Of these, one-fifth are whites (Spanish' South Amer-

Jan 1, 1885

By T. A. Griffin

Surface mining today is faced with a twin challenge: (1) accelerating the rate of removal of massive quantities of overburden and ore, and (2) replacing comparable high volumes of overburden in the mined-out portion of the pit. It is against this background, coupled with increased demands for fossil fuels worldwide and legitimate environmental concerns, that the role of bucketwheel excavators and reclaimers has been raised to new prominence.

Jan 10, 1974

By Emil Gathmann

STEEL as it is poured, or teemed, into the mold for forming the ingot may be broadly separated into two divisions; i.e., effervescing or gassy steel, also termed evolution steel, and non-effervescing or killed steel, also termed solution steel. Between these primary divisions there are various types having the characteristics of both divisions but really not belonging to either; such steels are termed semi-piping, rising, or wild, as the type may be. True unkilled, or effervescing, steel should contain large volumes of gases, which are evolved while the metal is being teemed, or cast from the ladle nozzle into the mold, and while the temperature of the steel is being reduced prior to the solidification or freezing of the steel, the upper portion, or top, of the ingot remaining liquid due to the evolution of gases until an ingot skin of considerable thickness has been formed. These gases consist principally of hydrogen, carbon monoxide, nitrogen, and ammonia. It is generally understood that nitrogen gases are the first evolved and form the skin blowholes, at times troublesome, in the forming solidifying ingot. Ingots made of effervescing steel will always contain a large number of blowholes. Such blowholes are not deemed objectionable in various products if they occur well within the interior of the ingot where they will not be subject to oxidation upon the ingot's cooling and subsequent re-heating and rolling or forging. Very little top or bottom discard is taken from this type of ingot as pipes, or large shrinkage cavities, at the upper portion of the ingot do not usually occur, the difference in volume between the liquid and the solid steel (6 to 10 per cent.) being compensated for by the innumerable blowholes distributed throughout the body of the , ingot. Of the 40,000,000 tons of steel made in the United States during the year 1919, at least 35,000,000 tons of ingots were made of gassy or semi-gassy steel. Killed, or solution, steel is termed true piping steel from the characteristic pipe or shrinkage cavity that usually occurs in the uppermost central portion of the ingot.

Jan 8, 1920

By P. W. George

THE rapid increase in cost of discovering new orebodies by churn drilling in the Tri-State district has led to some attempts to lessen the expense by using geophysical methods. Electrical prospecting was tried three or four years ago, but no successful results were recorded. In 1926, the Federal Mining and Smelting Co. engaged the North American Exploration Co., of Houston, Texas, to make some tests with the torsion balance. At first, it was thought that the most favorable conditions for discovery of ore deposits with the torsion balance would be in locations where the ore was known to occur at rather shallow depths, FIG. 1.-CROSS-SECTION OF DUENWEG LEASE. therefore the first trial was made at Duenweg, east of Joplin, where some zinc ore had been developed at a depth of 130 ft. The gravity gradients at 61 stations on a tract of about seventeen acres indicated plainly one large zone of maximum gravity and a smaller narrow zone of minimum gravity. Fourteen churn-drill holes, half of which struck ore, show that all the ore found was located outside the zones of maximum and minimum gravity. In the zone of maximum gravity the limestone beds were closest to the surface, and the first chert beds encountered were at the greatest depth. The results (shown in Table 1) indicated that the gravity of the limestone was greater than the gravity of the fractured chert together with its orebodies, and probably also greater than the bouldery soil and clay on top of the limestone. A cross-section of the Duenweg lease is shown in Fig. 1.

Jan 1, 1928

1. Healthy and active Local Section organizations, are vital factors in promoting the vigor and growth of the Institute. 2. Activity on the part of Local Sections should be recognized and stimulated by appropriation of funds from the Institute's treasury; and these appropriations should be as large as is consistent with the relative needs for other activities. 3. As between different Sections, the amount of such appropriations should.

Jan 1, 1939

JOSEPH DANIELS, Seattle; Wash. (communication to the Secretary*). Mine models are of great value to the student and to the layman in visualizing underground conditions, and, in a measure, should be just as much a part of the equipment of a mining school as sets of ore specimens, catalogs, or drawings. The chief drawback, as Professor Stock has indicated, is the time and cost of making them. The greatest good in the development of the model comes to the person who makes it, and I have often wondered whether it might not be possible to have each student make one model during his undergraduate career. At the University of Washington we have been collecting sets of mine timbers, made of 6 by 6-in. lumber, illustrating shaft, level, and stope timbering. This work has been done by freshmen. Perhaps each educational institution could specialize in the creation of a certain type of model and exchange its product for that of another school, just as we now do with ore collections. In this way we could build up good museums at a relatively low cost. JOHN R. CHAMBERLIN, New York, N. Y. (communication to the Secretary?).-The type of model described by Professor Stoek is admirably suited to exhibits of coal mining in horizontal veins, and fulfills perfectly the three purposes mentioned. As an educational illustration in colleges, especially when the students themselves build the model under the direction of their instructors, it is of the highest value; and as each condition in mining requires special methods to depict properly in a model, the student is compelled to exercise considerable inventive resource to construct a true representation, stimulating the imagination and interest in his subject. Models built for exhibits in lawsuits are usually constructed to show prominently some particular feature of vein formation or geology, or the relation of underground workings to surface property lines, and as such their use is invaluable to the successful litigant. When the litigation is ended, it is natural that the model should be relegated to the basement and frequently destroyed, as data on underground workings are often considered of a private character by the operators; and it is

Jan 10, 1917

By A. A. Mathews

During the past year (1967-68), there have been many instances of either partial or complete failure of a tunnel-support system. It looks like the art is in a pretty sad state, but as long as we permit the field of tunnel design to remain basically an art, that's about what we can expect. The application of scientific principles to tunnel design involves much more than assigning values to a series of factors in an equation. I am reminded of the case where the engineer calculated that steel ribs with struts were required to support a horseshoe-shaped tunnel in firm ground. The contractor had driven several hundred feet without installing the struts when the engineer visited the job. When he was informed that the struts had been left out, he fled the tunnel in alarm. As one authority has so aptly put it, "There is far too much calculating and too little observing." Initially, one might think of a tunnel support as a structural member, such as a strut or arch which is installed in order to support some definite load. Similarly, a tunnel lining might be considered as a treatment of the interior surface of the tunnel in order to produce desired aesthetic, hydraulic, or architectural results, or to serve a protective function. Actually, many linings, such as a concrete lining, serve a dual purpose and support a load as well as satisfy other requirements. Not too many years ago a tunnel, during the driving or excavating stage, was considered to be either supported or unsupported. In recent years, however, several techniques have been developed, which by helping the tunnel to support itself, permit the elimination of separate structural support. Since these techniques in many cases actually become a substitute for the conventional types of supports and linings, a state-of-the-art review would hardly be complete without including them for consideration. Thus, for the purpose of this discussion, we shall define tunnel supports as any system or technique which effectively maintains the integrity of the tunnel opening. In their chapters, both Jacobs (No. 6) and Lippold (No. 7) pointed out how support systems have advanced from timber supports to steel supports

Jan 1, 1970

By J. C. Bayles

THE most unsatisfactory occurrences in the experience of a manufacturer are those from which he suffers damage and learns nothing useful. That there are such incidents, and that they occur with annoying frequency, is unfortunately true. An accident which can be understood and explained always carries some consolation with it. However bad the copnsequencee, one finds comfort in reflecting that they might have been worse, and that the knowledge of how to avert a more disastrous calamity from the same cause is worth what it cost. But when an accident occurs, which remains unexplained after anxious days of investigation and sleepless nights of reflection, and which is as liable to occur twice or twenty times, as once, very little satisfaction of any kind can be extracted from it by the most philosophical victim. Three such incidents have come under my notice in one establishment. Fortunately none of them were attended with very serious consequences, as no one was hurt, and the damage to property was slight; but in each instance, loss of life and great destruction were escaped by so narrow a margin as to make them extremely disquieting. I have recorded them in the hope, that from the experience of others maybe gained what my own careful investigations have failed to reach-—satisfactory explanations. The first of these curious occurrences was the bunting of a 16-inch pipe carrying air under a compression of about 1 pound. The pipe was made of light galvanized iron with soldered seams. Into it a rotary fan-blower delivered air, and from it smaller pipes were carried to the furnaces. The blower was run continuously. Neither the main pipe nor its branches had any connection with the gas conduits. Both air- and gas-pipes delivered into the furnaces; but although the gas was under much higher compression than the air, there appeared to be no good reason why, having free escape in case of leakage, it should ever make its way back into the air-pipe. One warm afternoon in June the main air-pipe exploded with great vio-

Jan 1, 1891

By [Dipl. -Ing. ] Karl Angerer

The "New Austrian Tunneling Method" is one of the most significant developments in European tunneling in the last 15 years. I hope this report will show the significance of this tunneling method, which was developed in Austria exactly 18 years ago and which is now used in many European countries. In Austria from 1948 to 1953, the Moll tunnel with a length of 11.6 km (about 7.3 miles) was constructed as a part of the Kaprun power plant. Depth of overburden varied from 1000 to 1400 m, and there were many rock bursts in calcareous-schist formations. Here for the first time it was found that a thin concrete lining would help to prevent rock bursts if it was sprayed on the rock soon after blasting. During construction of the Prutz-Imst tunnel in Austria from 1953 to 1956, the shotcrete lining was sprayed on the phyllite surface a certain distance behind the blasting face to prevent rapid rock decomposition. This method was also tried in soft-rock sections of the tunnel where steel and wood supports usually were necessary. To prevent loosening of the rock, application of the sprayed concrete was tried immediately after blasting. This method made it possible to tunnel through very soft ground. Where necessary, the shotcrete was supplemented by steel arches and mesh reinforcement. At that time (1953-1956), the machines and equipment for guniting or spraying concrete were being improved rapidly and it became possible to spray aggregates up to 25 mm in diam. Hardening accelerators brought quicker strength and better adhesion of the shotcrete-this also made it possible to use the method in wet tunnels. If the tunnels are extremely wet or flowing with water, it is necessary to seal off the wet rock or drain the water, using, for instance, the Oberhasli method. After these first successful steps with the new Austrian method, large portions of the Schwarzach power plant in Austria were designed and built. At this operation, shotcrete was used almost exclusively for tunneling work. It was on this site where, for the first time, a tunnel 120 m long with a 45-sq- m section was driven through overburden without one piece of timber

Jan 1, 1970

By Rossiter W. Raymond

In the course of this address, President Raymond referred to the law, said to have been discovered at the French works of Terrenoire, that the amount of phosphorus may be increased without injury to steel, if the amount of carbon be proportionately decreased. The works named have been for more than a year, it is said, manufacturing in the open hearth, by the Martin process, steel rails containing as high as 0.35 per cent. of phosphorus, with about 0.15 per cent. of carbon, which were not found inferior to Bessemer rails. It is not claimed by the manager of the works that phosphorus is an ingredient to be preferred, or purposely introduced; but only that materials containing it (such as old iron rails, etc.), can be succesfully employed. Other parties have apparently a higher opinion still of the new manipulation, and are prepared to claim for " phosphorus steel" superior qualities. Mr. I. Lowthian Bell alluded to the subject in his recent address as President of the British Iron and Steel Institute, but without expressing a positive opinion. After pointing out that the commercial value of the process turned on the cheap manufacture of ferro-manganese, by means of which only could the necessary amount of manganese be introduced into the Martin bath, without increasing its contents of carbon, Mr. Raymond proceeded to say that the principle alleged to have been discovered at Terrenoire was already known years ago, in this country, at least. Not only had steel been manufactured here, containing high percentages of phosphorus, coupled with low percentages of carbon, and suitable for use in rails, boiler-plates, etc., but the reason of its surprising qualities had been distinctly surmised, if not widely proclaimed. The following analyses and extracts from private letters prove these assertions. Some of them assert a similar principle in .the case of wrought iron; but the analyses, and the remarks based upon them, have reference solely to the steel manufactured under the superintendence of Mr. Slade, at the works of the New Jersey Steel and Iron Company in Trenton.

By Rossiter W. Ph. D. Raymond

(From the President's Address at St. Louis, 1874.) IN the course of this address, President Raymond referred to the law, said to have been discovered at the French works of Terrenoire, that the amount of phosphorus may be increased without injury to steel, if the amount of carbon be proportionately decreased. The works named have been for more than a year, it is said, manufacturing in the open hearth, by the Martin process, steel rails containing as high as 0.35 per cent. of phosphorus, with about 0.15 per cent. of carbon, which were not found inferior to Bessemer rails. It is not claimed by the manager of the works that phosphorus is an ingredient to be preferred, or purposely introduced; but only that materials containing it (such as old iron rails, etc.), can be succesfully employed. Other parties have apparently a higher opinion still of the new manipulation, and are prepared to claim for "phosphorus steel" superior qualities. Mr. I. Lowthian Bell alluded to the subject in his recent address as President of the British Iron and Steel Institute, but without expressing a positive opinion. After pointing out that the commercial value of the process turned on the cheap manufacture of ferro-manganese, by means of which only could the necessary amount of manganese be introduced into the Martin bath, without increasing its contents of carbon, Mr. Raymond proceeded to say that the principle alleged to have been discovered at Terrenoire was already known years ago, in this country, at least. Not only had steel been manufactured here, containing high percentages of phosphorus, coupled with low percentages of carbon, and suitable for use in rails, boiler-plates, etc., but the reason of its surprising qualities had been distinctly surmised, if not widely proclaimed. The following analyses and extracts from private letters prove these assertions. Some of them assert a similar principle in -the case of wrought iron ; but the analyses, and the remarks based upon them, have reference solely to the steel manufactured under the superintendence of Mr. Slade, at the works of the New Jersey Steel and Iron Company in Trenton.

Jan 1, 1875

By Byron Bird

WHILE Mr. Fahrenwald has been working on the fundamentals of ore-dressing, in Idaho, the Northwest Experiment Station of the U. S. Bureau of Mines, in cooperation with the University of Washington, has been studying the corresponding fundamentals for the closely-allied subject of coal-washing. In this work many of the principles outlined in Mr. Fahrenwald's paper have been touched on, one important exception being that phase of his studies where conditions were approximated between those existing on a table and those existing in a hindered-settling classifier. During the past three years this work has been given over almost exclusively to a study of coal-tabling to devise better methods of cleaning fine sizes of coal, particularly the coals of the Northwest, which are very difficult to wash. One important result of this study thus far has been the development of a satisfactory hindered-settling coal classifier, now in use in several commercial plants. Recently table stratifica-tion has been the subject for study. This latter phase of the work with coal,. as well as the earlier portion dealing with hindered-settling classification, has in a measure paralleled Mr. Fahrenwald's work with ore. Without going into details about the results of the coal experiments, I shall merely say that, from a quali-tative standpoint, they are, in general, concordant with Mr. Fahrenwald's, but that from a quantitative stand-point the results, particularly those with, table strati-fication, are somewhat different. These differences may disappear as the work progresses-Mr. Fahrenwald is further ahead with his experiments than we are at the Northwest Station-but if not, the disparity would not be surprising, and indeed would be what one might reasonably expect when investigators work on two very dissimilar materials and use different apparatus and methods of study. However, this- mention of our coal-washing experiments is made only in passing. A principle of general application that may be estab-lished from Mr. Fahrenwald's paper is that different types of stratification should be used in successive' gravity-concentration processes to. obtain best results.

Jan 3, 1927

The objective of the mission was basically to study the utilization of engineers and engineering technicians and their interrelationship in the Soviet Union. Beginning with their graduation from the engineering institutes and technicums, we hoped to learn how the graduates started out in industry, what their training on the job was, what sort of work they did, and how they worked themselves up within their profession. However, it turned out that, as our host was the Ministry of Higher and Secondary Education, most of our visits were to educational establishments. Our itinerary covered Moscow, Leningrad, Kharkov, Rostov, Baku, and Tashkent, with a side trip to Samarkand. In all, we visited 13 technical institutes, three technicums, and five industrial plants or enterprises, as they are called there. Our trip was one of only four weeks. Our observations were limited by the few cities and enterprises we were permitted to visit. Nevertheless, we did come back with some definite impressions and conclusions which we feel should be of interest to engineers, educators, and those concerned with the relative economic and technical power of the USSR and the U.S.

Jan 9, 1960