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By R. W. Diamond

THREE mills are now operated by the Consolidated Mining & Smelting Co. of Canada, Ltd:: (1) The Sullivan concentrator, Chapman, B. C. (near Kimberley, B. C.), (2) the St. Eugene concentrator, Moyie, B. C., and (3) the Tadanac (customs) concen-trator, Trail, B. C. Differential flotation is the only concentration method employed in all three plants. Tables are used for pilot work only. Flotation equip-ment and control are similar in the three mills, and the flow sheets at the St. Eugene and Tadanac mills, while much simpler, are modeled after that of the Sul-livan concentrator. Successful differential flotation of Sullivan ore com-menced in the spring of 1920, in the pilot concentrator at Trail. During 1920, 193,804 tons were treated by this process. This operation continued without interrup-tion and with steady growth. For the first 7 months of . 1923, which concluded the pilot plant operation, ap-proximately 1100 tons were treated daily. I believe the Sunnyside plant of the United States Smelting &. Refining Co. was the only successful and large scale operation practising differential flotation prior to 1920. in North America. The Sullivan ore, because of its high iron content, was quite a different problem from that at Sunnyside. The entire tonnage of Sullivan ore had to be separated into three sulfide concentrate products-lead concentrate, zinc concentrate and iron concentrate. The choice and arrangement of equipment, and the original flow sheet for the Sullivan concentrator were controlled by the results of the exhaustive pilot mill test. These covered a continuous period of 3 1/2 years and involved the treatment of 1,076,368 tons of Sullivan ore. Satisfactory recoveries are made from feed; 11.0 per cent lead and 7.5 per cent zinc in the form of lead concentrate containing 69 per cent lead, 4.5 per cent zinc, and zinc concentrate containing 3.0 per cent lead and 49 per cent zinc. (The pure zinc mineral in Sulli-van ore is marmatite, 'containing approximately 54.5 per cent zinc and 10 per cent iron. It is apparent, there-fore, that 49 percent concentrate is high grade for this particular ore.)

Jan 8, 1927

SAN FRANCISCO LOCAL SECTION Executive Committee G. HOWELL CLEVENGER, Chairman C. W. MERRILL, Pace-Chairman JAMES C. RAY, Secretary-Treasurer, 1235 Webster St., Palo Alto, Cal. F. W. BRADLEY ANDREW C. LAWSON Meets on the second Tuesday of each month Farewell Dinner to H. Foster Bain H. Foster Bain, Who has gone to London to assume the editorship of the Mining Magazine, was tendered a farewell dinner by the San Francisco Sections of the American Institute of Mining Engineers, the Mining and Metallurgical Society of America, and the Engineers' Club, on the evening of Mar. 9, 1915, at the Hotel Bellevue, San Francisco, 85 members being present. George H. Clevenger acted as Toastmaster and the following toasts were responded to: Bain and the Mining Industry, E. H. Benjamin. Bain, the Geologist, A. C. Lawson. Bain, the Man, F. W. Bradley. Bain, the Friend, C. W. Merrill. Bain, the Schoolboy, C.. F. Tolman. The Frontispiece and Flow sheet from the souvenir program, designed by James C. Ray, Secretary of the Section, are reproduced herewith.

Jan 5, 1915

By F. W. McQuiston

Idarado Mining Company's mill and surface plant are at the portal of the Treasury tunnel at elevation 10,625 ft, 12 miles south of Ouray, Colo. In 1943 and 1944 this tunnel was extended in a westerly direction to tap the Black Bear vein, and, together with the recently completed 1100-ft inclined Treasury raise, provides access to the Black Bear mine. In 1945 a 250-ton mill was placed in operation to process development ores containing much needed copper, lead and zinc for war requirements, and to serve as a pilot testing unit for larger scale milling operations. In the years 1902 to 1927 some 329,000 tons of ore were produced from mine workings on the Black Bear vein that extended downward from elevation I2,325 ft at the Black Bear tunnel portal to elevation 11,618 ft, the lowest level of the mine. The ores were taken to the Cascade and Smuggler-Union mills near Telluride over two aerial tramways. Gold bullion, a copper-lead concentrate, and a zinc concentrate were produced. Ores The Black Bear is a compound fissure vein that has undergone several stages of mineralization. The first important stage is represented by complex ores of copper. lead and zinc in a quartz gangue. Precious metal content in this stage is low. The galenn is argentiferous and varying amounts of tetrahedrite, freibergite and bornite tend to increase the normal copper content represented in chalcopyrite. The zinc occurs as a true sphalerite with little or no iron. Later re-openings of the fissure took place more or less co-extensively with the successive introduction of (I) abundant quartz gangue containing minor amounts of chalcopyrite, galena and sphalerite; (2) free gold in a fluoritic quartz gangue; and (3) barren, low-grade quartz with minor amounts of pyrite as the only important sulphide. The sulphides show practically no oxidation and little mineralogic inter-growth. Because of the common overlapping of these successive stages of mineralization within a given mining area, considerable dilution of the base-metal content takes place, thus lowering the average mill-head grade. Plant Practice Metallurgical testing was started shortly after the Black Bear vein was encountered on Treasury tunnel level in 1944. Laboratory tests showed good flotability of the minerals in the ore and indicated an economic separation could be made of the copper, lead and zinc minerals into their respective concentrates. The success of the separation is close reagent control to maintain a balance between promotion and depression of the sulphides. To maintain this balance reagent consumption for the three metal separation is considerably higher than in ordinary lead-zinc flotation.

Jan 1, 1949

By C. W. Pollock

THAT a distressing explosion of some magnitude did not take place in the Berry No. 3 mine of the Ford Collieries Co. recently was solely because no source of ignition was present when the stage was set for such an occurrence. The mines of this company, which are in West Deer Township, Allegheny' County, Pa., have been operating in the double or thick Freeport seam since 1.909. During this entire period they have been classed as gaseous by the Pennsylvania Department of Mines, and some gas has been encountered from time to time almost entirely however in development work in the vicinity of clay veins or wants-and never to my knowledge on gobs or in rib work.

Jan 1, 1935

By B. M. Larsen, T. E. Brower

For some years we have been carrying on a rather comprehensive investigation of the occurrence of oxygen in liquid open-hearth steel. This investigation was interrupted by the war emergency and is therefore incomplete, with many questions still answered only partially, if at all; yet it seemed worth while to present a report of progress on this difficult field of research, if for no other reason than to promote discussion and further investigation of this important problem. The significance of such studies depends in large measure upon the accuracy of measurements of oxygen content in liquid steel while it is still in the furnace or as it flows into the ladle, or thence into the mold and there is, as we shall show, good reason for believing that the main source of uncertainty is in the sampling, not in the analytical method as such. The difficulty arises from the fact that any method of sampling is of itself apt to alter the amount of oxygen in solution in the liquid steel, because this oxygen is in a readily reactive condition. On the one hand, being usually present at a concentration appreciably in excess of that corresponding to equilibrium with the carbon then present, it may decrease rapidly in percentage by reaction with carbon and evolution of CO, especially if the liquid metal is in any way shaken or brought in contact with a cooler solid surface. On the other hand, it may increase rapidly by ab- sorption of oxygen from a slag, a furnace atmosphere, or from air. These circumstances, which are inherent in the problem, as well as our conclusion that, despite the considerable amount of careful work already done, there is still no method of sampling liquid steel acceptable as an unquestioned standard, ed us to undertake systematic comparisons of oxygen content of large numbers of samples taken: (I) by a single method at different positions and levels in the bath; (2) at the same place by different sampling methods; and (3) from bath, tapping stream and pouring stream. The different sampling methods yield somewhat different values and there is as yet no way to tell with certainty which is the most accurate. But the general reproducibility and consistency of the results give us some confidence in certain inferences we draw from them: namely, that the "spoon" method of sampling, properly carried out, gives somewhat more consistent results than the "bomb" method, as it has usually been practiced; that, in the bomb method, an aluminum cap is preferable to a steel cap; that the oxygen content of liquid steel in a finished heat is substantially the same all over the bath at the same level, and tends to decrease at lower levels further from the slag interface; also that it tends to decrease, and to decrease erratically, from furnace bath to tapping stream entering the ladle. Accordingly it seemed desirable to report these observations in detail as a first step, so that the reader may judge their significance as a contribution towards solution of the main problem, which is to find a means of pre-2

Jan 1, 1945

By Francis A. Pocock

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

Jan 1, 1890

By Harry T. Hamilton

THE genial assistant to the president of the New York Trust Co. is the latest addition to the Institute's board of directors, having been elected at the March meeting of the hoard to fill the unexpired term of the late E. E. Ellis. Usually when a banker is appointed to the board of a company the reason is obvious; the difference in this case is that the New York Trust Co. has some of the Institute's money, instead of vice versa. But Harry Hamilton is not really a banker-at least not primarily. Frefluently big financial institutions have a good mining engineer on their staffs to keep them from financing too many "cats and dogs." At any rate Mr. Hamilton gave up his consulting practice in San Francisco back in 1927, to accept his present position in New York. Until then, from the time he graduated from Yale in 1904, lie was constantly engaged in mining operations of one kind or another in the West and in Mexico. His first job was at Christmas, Ariz., where lie did "sampling and miscellaneous work" for the Saddle Mountain Mining Co. The writer tramped up to, all over, and through that property one hog day many years later, when it was run by the Christmas Mining Co., and carp assure the reader that without doubt the young Yale graduate got some good experience and was well broken in. From there Mr. Hamilton went to Cananea for a time, and then to the Copper Queen, at Bisbee, where he was a valued member of the rigging gang. An assignment of assaying and sampling for the Shan¬non Copper Co. at Metcalf lasted for a few months and then he accepted a job for a year with the geological department

Jan 1, 1936

By Thomas M. Dr. Drown

REMARKABLE as have been the direct results of Danks's puddler, there are some indirect and incidental results, which are well worthy of study for their intrinsic value and suggestiveness. The success of Danks's machine is due mainly to the nature of the lining and the manner in which it is attached to the walls of the revolving chamber. Herein lies Danks's merit and good fortune. Given such a lining, and the success of the machine, as far as puddling iron is concerned, could easily be predicted. Other important results have, however, been obtained with this machine, which, though clearly explicable, were, nevertheless, unanticipated. These are the increased yield of bar-iron over the pig-iron charged, and the elimination of phosphorus, which, though not absolutely complete, is yet more decided than in the case of hand-puddling. As regards the increased yield, this is merely what we have a right to expect if we consider the puddling process to consist in the oxidation of the carbon and silicon of the pig by the oxygen of the oxide of iron. That this result is attained, nearly to the extent that the theory requires, in Danks's puddler, and has never been more than partially attained by the most careful experiments in hand-puddling, points clearly to the fact that the contact of the molten pig-iron with the oxide of iron is much more intimate and complete in the one instance than in the other. The action of puddling in Danks's machine may be considered to be twofold first, the removal of the carbon, silicon, and phosphorus of the pig, which is the primary object, and, second, the production of wrought iron direct from the ore, which is entirely an incidental result. Intelligent metallurgists were not long in recognizing in this latter result a fact of deeper import and greater value than the attainment of a perfect puddling process. A new method

Jan 1, 1874

By R. Dawson Hall

WHAT are the opportunities for the services of engineers in the coal mines? The best answer perhaps can be made by detailing the present lines of development in the bituminous coal mining regions. They are just at the beginning of a period that can be conservatively termed revolutionary. A few glimpses of new possibilities in economic mining that will reduce the cost of bituminous coal at the mines by at least one half have convinced almost everyone that a change must shortly come about. The cost of housing has become such a burden, especially in mountainous regions, that development which demands the hiring of more men and constructing more houses would not be profitable. The introduction of mechanical aids to mining, transportation and dumping suggests a way of obtaining a large tonnage with the same or a smaller number of men with no further house construction. At the same time the restriction of immigration has made it increasingly difficult to obtain men inured to hard labor. Modern civilization is not productive of muscular energy and at the same time it provides men who are not indisposed to the use of the mental effort required to direct the physical forces now available for the replacement of such energy.

Jan 1, 1924

By E. P. Mathewson

The early development of the reverberatory furnace for smelting copper-ores was the work of the Welsh smelters, particularly those of Swansea. The first record of a reverberatory furnace is made by Jars, who states that in 1755 copper-smelting was effected .in reverberatory furnaces at Middleton-Tyas, in Yorkshire, England. The first patent, of any importance, for improvements in reverberatory furnaces was granted to Thomas Williams in 1778 for the granulation of the regulus. The next was that of William Evetts, in Sheffield, in 1812, for the cooling of the fire-bridge by the admission of air. Charge-hoppers above the furnaces were in common use in 1848. The size of the hearth of the furnaces about the beginning of the 19th century was commonly 11 by 8 feet. No material development was made until the Welsh process mas brought to Colorado, where Richard Pearce, as manager of the Argo works, near Denver, developed the furnace to meet the requirements of a custom plant, under keen competition with lead-silver smelting-plants, using blast-furnaces. His improvements are outlined in Fig. 1, elaborated by permission from E. D. Peters's excellent work,' to which the reader is referred for further details. This figure shows that the furiiaces were in 1878, 9 ft. 8 in. by 15 ft. in hearth; and in 1894, 16 by 35 ft., while the capacity of the furnace had been increased from 12 tons per 24 hr. to 50 tons in the same period.

Jan 1, 1913

By Thomas M. Drown

Remarkable as have been the direct results of Danks's puddler, there are some indirect and incidental results, which are well worthy of study for their intrinsic value and suggestiveness. The success of Danks's machine is due mainly to the nature of the lining and the manner in which it is attached to the walls of the revolving chamber. Herein lies Danks's merit and good fortune. Given such a lining, and the success of the machine, as far as puddling iron is concerned, could easily be predicted. Other important results have, however, been obtained with this machine, which, though clearly explicable, were, nevertheless, unanticipated. These are the increased yield of bar-iron over the pig-iron charged, and the elimination of phosphorus, which, though not absolutely complete, is yet more decided than in the case of hand-puddling. As regards the increased yield, this is merely what we have a right to expect if we consider the puddling process to consist in the oxida tion of the carbon and silicon of the pig by the oxygen of the oxide of iron. That this result is attained, nearly to the extent that the theory requires, in Danks's puddler, and has never been more than partially attained by the most careful experiments in band-puddling, points clearly to the fact that the contact of the molten pig-iron with the oxide of iron is much more intimate and complete in the one instance than in the other. The action of puddling in Danks's machine may be considered to be twofold: first, the removal of the carbon, silicon, and phospho rus of the pig, which is the primary object, and, second, the produc tion of wrought iron direct from the ore, which is entirely an inci dental result. Intelligent metallurgists were not long in recognizing in this latter result a fact of deeper import and greater value than the attainment of a perfect puddling process. A new method

By C. B. Sclar and

A graphical solution is presented for the equation v =v &-cU where vb is the volume of liquid b of density 6 that must be added to liquid a of volume va and density d, in order to obtain a heavy-liquid solution of preferred density dm for mineral fractionation. The equation is valid only for pairs of liquids whose volumes are additive, but empirical density-composi-tion data show that this condition is met over wide compositional ranges by all of the heavy solutions that are commonly used for mineralogical analysis. The chart is a nomograph which consists of two horizontal volume scales ad a vertical density scale arranged so that one volume scale occurs on each side of the density scale. All the scales are linear. For two liquids of density d, and &, respectively, each volume scale has an independent level on the density scale, ad the graphical solution for vb on the nomograph is obtained by construction of one straight line. The chart can be prepared easily to cover any density range with any desired accuracy by proper selection of the scales. Heavy-liquid separation of particulate samples is an indispensable analytical procedure in the mineralogical and mineral-process ing laboratory. Heavy liquids may be used 1) to isolate specific minerals in the form of high purity products or to fractionate samples into several products with density limits for petrographic, chemical, spectrographic, and X-ray diffraction analysis,'-' 2) to determine the density of minerals,'-l4 3) to facilitate the recognition and identification of optically similar associated minerals,15 and 4) to determine quantitatively the degree of liberation of ore minerals in ores and mill products at various limiting sizes." The preparation and recovery of heavy liquids suitable for mineralogical analysis are discussed fully in the literature and operational procedures and special equipment for heavy-liquid separation are described in numerous references.'747837' 13,18,25-42 Useful tabulations of heavy liquids for mineralogical analysis are given by Tickell, Mil-ner,' Twenhofel and Tyler,' and Lange and a very complete up-to-date list of minerals arranged according to increasing density is given by Mursky and Thompson. USEFULNESS OF THE DENSITY CHART For any particulate sample, the limiting densities selected for its fractionation by means of heavy- liquid separation depend on the respective densities of the constituent minerals and the specific objectives of the separation. In many instances, the densities of readily available and practicable heavy liquids do not coincide with those that are required, and suitable liquids of the proper density are obtained by dilution with miscible liquids. In the general case, one may wish to mix either a pure liquid (A) or a solution of two miscible liquids (AP,,) of known density with either a pure liquid (B) or a different solution of the two miscible liquids (A,B,) of higher or lower density in order to obtain a final liquid of the preferred density. In conventional practice, the latter is reached empirically by trial-and-error addition of increments of one liquid to the other. The density of the final solution may be determined either by accurately weighing a known volume of the final liquid,'' 532;4;40, or by means of I)a Westphal balance, 2)a hydrometer, a refractometer in the case of binary liquid systems for which density-refractive index data are available,15 4) natural or synthetic .indicators of known density, a pycno-meter. Like all trial-and-error methods, these procedures are time consuming and many require special equipment which may not be available, The purpose of this paper is to show that the volume of a liquid of known density which is to be added to another liquid of known volume and density in order to obtain a solution with an intermediate preferred density may be determined rapidly and accurately by a graphical method provided that the two liquids form ideal or quasi-ideal solutions whose volumes are additive. Empirical data47'8~'8~4B'49 show that solutions prepared from pairs of miscible

Jan 1, 1961

By S. F. Shaw

The Sierra Mojada mining district is situated in western Coahuila, about 8 km. east of the Chihuahua state line, and about one-half way from the northern to the southern extremity of the state. It is at the terminus of the Mexican Northern R. R., 125 km. northeast of Escal6n, Chihuahua; also about, 240 km. due west of Monclova, Coahuila. The altitude is approximately 1500 m. above sea level. The Sierra Mojada valley is about 10 km. long, from east to west, with a width of 1 to 2 km. It is approached from the east through the Puerto del Oro, where the Mexican Northern R. R. enters the valley; the slope from west to east is gentle. The Sierra Mojada, of which about 300 m. is an almost vertical wall, bounds the valley on the south side; on the north side, the slope to the crest of Sierra Planchada is more gradual, rising only 200 or 300 m. above the valley. Water is relatively scarce in the district, and there are no running streams. The rainy season, usually beginning at the middle of June, lasts through July, and occasionally into August or September. In some years the rains fail entirely. The slope of the ground is such that nearly all the water immediately runs off. The arroyos along the flanks of the mountains are not very deep, but in heavy rains, sometimes approaching cloudbursts, a tremendous volume of water rushes down them, carrying large boulders. A certain amount of seepage collects in the agglomerate, lying below the conglomerate, and is retained in the local fractures. Some shallow wells have been sunk in this agglomerate, and one well over 150 m. deep was sunk on the Volcan ranch, supplying about 76 1. (20 gal.) per min. A considerable supply of water is collected in large earth reservoirs in and below the town of Esmeralda. In ordinary years this supply will last until January or February, after which the Volcan well has to be depended on until the next rainy season. Vegetation is scarce, aside from scanty scrub oak and other brush in the mountains, and a few mezquite, locust, pepper, and cottonwood trees

Jan 1, 1923

By S. F. Shaw

The Sierra Mojada mining district is situated in western Coahuila, about 8 km. east of the Chihuahua state line, and about one-half way from the northern to the southern extremity of the state. It is at the terminus of the Mexican Northern R. R., 125 km. northeast of Escal6n, Chihuahua; also about, 240 km. due west of Monclova, Coahuila. The altitude is approximately 1500 m. above sea level. The Sierra Mojada valley is about 10 km. long, from east to west, with a width of 1 to 2 km. It is approached from the east through the Puerto del Oro, where the Mexican Northern R. R. enters the valley; the slope from west to east is gentle. The Sierra Mojada, of which about 300 m. is an almost vertical wall, bounds the valley on the south side; on the north side, the slope to the crest of Sierra Planchada is more gradual, rising only 200 or 300 m. above the valley. Water is relatively scarce in the district, and there are no running streams. The rainy season, usually beginning at the middle of June, lasts through July, and occasionally into August or September. In some years the rains fail entirely. The slope of the ground is such that nearly all the water immediately runs off. The arroyos along the flanks of the mountains are not very deep, but in heavy rains, sometimes approaching cloudbursts, a tremendous volume of water rushes down them, carrying large boulders. A certain amount of seepage collects in the agglomerate, lying below the conglomerate, and is retained in the local fractures. Some shallow wells have been sunk in this agglomerate, and one well over 150 m. deep was sunk on the Volcan ranch, supplying about 76 1. (20 gal.) per min. A considerable supply of water is collected in large earth reservoirs in and below the town of Esmeralda. In ordinary years this supply will last until January or February, after which the Volcan well has to be depended on until the next rainy season. Vegetation is scarce, aside from scanty scrub oak and other brush in the mountains, and a few mezquite, locust, pepper, and cottonwood trees

Jan 1, 1923

By R. A. Perry

DURING 1943, supplies of lead, like those of most base metals, moved from a position of scarcity to one of ample supply for all possible war requirements. The principal worry in the market, as 1944 began, was that surplus stocks might increase too rapidly to maintain price stability. The problem of postwar stockpiling had definitely entered the picture. The end of the year finds the lead industry having met all use demands, but not without depleting stocks to a critical low in spite of heavy importations. The principal reason for this dangerously reduced stock position is lack of adequate man power, which, without question, has become the lead industry's number one problem. This condition became obvious about the middle of the year, after Selective Service placed in effect orders that no deferments would be given employees under 26 years of age, and to a complacent attitude toward the industry assumed by the War Manpower Commission. It has become progressively worse since then. The WPB continued its policy, started during 1943, of easing restrictions on materials to be used for maintenance, repairs, and operating supplies. The policy of premium payments established by the Metals Reserve Co. was continued and, in spite of expressions to the contrary, has proved quite satisfactory. In short, the Government continued its program of stimulating the lead industry in practically all

Jan 1, 1945

By A. A. Dor

Of the numerous methods that have been tested or considered for the beneficiation of low-grade iron ores, this article deals only with proven flowsheets that are adopted in plants in operation or which have been reliably pilot-plant tested. Several recommended layouts are described and discussed. They illustrate recent trends and embody improvements and new features that have resulted from the experience acquired in the operation of the plants already in service. They have been developed, in the last few years, in the course of designing several iron ore beneficiation plants of various types and sizes. Some of the design features in the layouts which are submitted represent, in some respects, personal views and may not meet the full approval of others in this field. It is hoped that this presentation will provide an opportunity for constructive discussion of the problems involved and of suitable solutions.

Jan 6, 1962

By W. W. Eckles

This paper is presented as a suniniary report of the use of well gas composition correlations obtained from mass spectrometer recordings as a means of identification and determination of reservoir continuity. Conventional methods for detecting composition differences are en-pensive, elaborate, and difficult to obtain. This excludes the use of extensive composition data for most applications. During recent years the mass spec-trometer has come into general use as an analytical tool in petroleum refineries. The use of mass spectrometer composition patterns ir~ characterizing or "finger-printing" the produced gas from a reservoir, presents a novel method for correlatitlg gas samples from well to well. The mass spectrometer provides a trace similar to an electric log. having peaks which represent the abuntlnnce of certaitz hydrocarbons in the well gas sample. Without going further into the detailed analysis the idea has been advanced that these traces or patterns could be used as a means of identifying a particular natural gas. This theory has proven to be essentially correct. The mass spectrometer pattern method is simple and cheap as COi?7pared to other standard methods. It greatly facilitates the solution of reservoir and geological problems in which correlation of well gas Com-positions is a factor. Specific field applications have been made. This paper concerns the results obtained in 465 individual gas analyses from 35 fields and 77 res- ervoirs. In a number of cases it has been found that such data have been extremely valuable in the determination of reservoir continuity. In at least one case, the method was a valuable contribution in tracing a reservoir from sand to sand in a coinplex fnulted field involving n11rnerous gas reservoirs. Field applications are presented to illustrate the possibilities of the method at the present stage of developnient and to stimulate the ernployrnent of this new approach by geologists and petroleum engineers in the industry. INTRODUCTION Identification of producing horizons and the determination of reservoir continuity are often a problem in those areas where dome structures and highly faulted sands are encountered. To complicate the picture further, there may be numerous sands, one on top of the other which dip and diverge in different directions. Even though it may be possible to develop some solutions to the preceding problems on the basis of the geological and reservoir data on hand. it is readily recognized that substantiating data based on independent methods would he extremely valuable. It has been found through field studies that correiation of well gas composition can be used to advantage in the geological and engineering study of a complex reservoir identification problem. METHOD FOR COMPARISON AND CORRELATION OF WELL GAS SAMPLES Since a large number of well gas samples are required in a gas identification or reservoir con- tinuity problem, it is necessary that a method of analysis be employed which can detect differences in composition readily and inexpensively. Although detection would be possible by means of low temperature fractional distillation (POD) analpsis, the method requires a relatively large sample and is comparatively slow and expensive to run. The mass spectrometer affords an inexpensive and precise analysis of small well gas samples taken at the surface which are about 1/300 as large as a POD sample. These samples can be obtained by regular field personnei and shipped to the spectrometer for analysis. It is, therefore, a practical approach to the problem. A typical record from the mass spectrometer is illustrated in Fig. I. The peaks on the record represent the abundance of ions produced from the different hydrocarbon molecules making up the gas sam-ple. In well gas comparisons only five peaks are employed, since the other peaks are formed from the same gas molecules and furnish no additional information. The five peaks used represent the abundance of methane, propane, ethane, butane and heavier, and oxygen. They are referred to respectively as the 16, 29, 30, 43, and 32 peaks. The oxygen peak is used to correct for air content in

Jan 1, 1958

By Ovid W. Eshbach

ENGINEERING education has been powerfully affected by the impact of war, just how powerfully can be better understood after considering the postwar problems regarding students, staff, and plant. In time of war no one will question the necessity of expediency of military training. With the cessation of hostilities, expediency gives way to the evolutionary process of strengthening engineering education as need is exemplified by experience. During the war, except for the Navy V-12 program, engineering education was at its lowest ebb of the century. Freshman enrollments were largely limited to those graduating from high school at the age of seventeen; and the upperclass, to those disqualified for active service. In most schools the experienced staff was either in service or government and industrial research. Many may never return to their former occupations. The most immediate problem is that of maintaining and building a staff to meet the enrollment of returning veterans. It is estimated that out of the eleven

Jan 1, 1945

By William L. Fink and

Although age-hardening in an aluminum-base alloy containing magnesium was observed by Alfred Wilml as early as 1911, it was not until 1919 that a theory of the mechanism of age-hardening was proposed. Merica, Waltenberg and Scott12 studying the age-hardening characteristics of Duralumin at the National Bureau of Standards, came to the conclusion that age-hardening of this alloy is caused by the precipitation of CuAl2, which is less soluble at the aging temperature than at the solution heat-treating temperature. It was postulated that the initially precipitated particles were of fine colloidal dimensions but that they gradually grew in size. Maximum hardness was assumed to be attained when the particles reached a critical size. This theory was at first received skeptically, since it was a widely accepted view at that time that the solid solution state should represent the hardest state of an alloy. Shortly thereafter, Jeffries and Archer proposed their well-known slip interference theory.'13 They suggested that age-hardening was accomplished by the precipitated particles acting as keys interfering with slip along crystallographic glide planes. They showed that this mechanical theory led direct,ly to the assumption that maximum hardening would be produced by particles of a critical size, which they suggested would have a diameter approximately 10 times that of the aluminum atom. This contribution amplified and explained so rationally the age-hardening theory of Merica, Waltenberg and Scott that wide acceptance resulted. Objections to Simple Precipitation Theory From time to time certain experimental facts have been cited against the simple precipitation theory. The first of these was the discovery by Fraenkel4 that, although the electrical resistivity of Duralumin decreased during aging at higher temperatures (from 100' to 250' C.), it increased during aging at ordinary temperatures. This was not in accordance

Jan 1, 1940

By William L. Fink and

Although age-hardening in an aluminum-base alloy containing magnesium was observed by Alfred Wilml as early as 1911, it was not until 1919 that a theory of the mechanism of age-hardening was proposed. Merica, Waltenberg and Scott12 studying the age-hardening characteristics of Duralumin at the National Bureau of Standards, came to the conclusion that age-hardening of this alloy is caused by the precipitation of CuAl2, which is less soluble at the aging temperature than at the solution heat-treating temperature. It was postulated that the initially precipitated particles were of fine colloidal dimensions but that they gradually grew in size. Maximum hardness was assumed to be attained when the particles reached a critical size. This theory was at first received skeptically, since it was a widely accepted view at that time that the solid solution state should represent the hardest state of an alloy. Shortly thereafter, Jeffries and Archer proposed their well-known slip interference theory.'13 They suggested that age-hardening was accomplished by the precipitated particles acting as keys interfering with slip along crystallographic glide planes. They showed that this mechanical theory led direct,ly to the assumption that maximum hardening would be produced by particles of a critical size, which they suggested would have a diameter approximately 10 times that of the aluminum atom. This contribution amplified and explained so rationally the age-hardening theory of Merica, Waltenberg and Scott that wide acceptance resulted. Objections to Simple Precipitation Theory From time to time certain experimental facts have been cited against the simple precipitation theory. The first of these was the discovery by Fraenkel4 that, although the electrical resistivity of Duralumin decreased during aging at higher temperatures (from 100' to 250' C.), it increased during aging at ordinary temperatures. This was not in accordance

Jan 1, 1940