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By AIME AIME

T HE Institute of Metals Division and the Iron and Steel Division will meet jointly at the Stevens Hotel, Chicago, during the week of the American Metals Congress, Sept. 22-26. The Iron and Steel Di- vision of the American Society of Mechanical Engineers, the American Society for Steel Treating and the American Welding Society meet at the same time. but the sessions have been arranged to conflict as little as possible. A rich program of papers and plant visits has been arranged for the members and guests of the two Institute Divisions. The annual dinner and a pro- gram of entertainment are being arranged by the Woman's Auxiliary of the Chicago Section. Members are urged to register immediately up011 arrival and to make dinner and plant visit reservations at the same time.

Jan 1, 1930

By M. L. White, J. L. Shafer, C. L. Caenepeel

Often an in situ leach is the only practical economic method for copper recovery from small low grade oxide deposits. The decision to develop a copper property by an in situ blast and leach is strongly dependent on ore grade, tonnage, hydrology, and the copper extraction and acid consumption rates. The inherent leachability of the ore will in part determine the desired amount of fracturing of the ore deposit by the blast in order to obtain a copper extraction rate that is economical. For the last several years Occidental Research Corp. (ORC), has undertaken a modest effort to address the question of how to best identify and determine the information necessary to predict and control the operation of an in situ leach for the economic recovery of copper.

Jan 2, 1979

By C. S. Matthews, H. C. Lefkovits

Drilling progress is often delayed by sticking of the drill string. The development of preventive and remedial methods has been hampered by incomplete understanding of the sticking mechanism. A recent lahorntory investigation hns indicated that one type of sticking may be attributed to the difference in pressure between the borehole and formation. This paper shows, by means of soil mechanics, that the primary cause for differential pressure sticking is cessation of pipe movement, whereas diflerential pressre and stanrtding time determine the severity of the sticking. The analysis stresses the importance of using low-weight muds with low solids content and low water loss to alleviate diflerential pressure sticking and describes why packed hole drilling, long strings of drill collars, and a large deviation from the vertical are conducive to sticking. Finally, preventrve and remedial methods ore evaluated, and a theory is presented on the release of stuck pipe by spotting oil. INTRODUCTION Since drilling with long strings of oversize drill collars has become standard practice in many areas, the incidence and severity of the stuck pipe problem has increased. It has been noticed that in the majority of these cases the sticking could not possibly be attributed to key seating or caving of shales. It appeared that, due to the differential pressure between the mud column and the formation fluid, the collars were pressed into the wall and so became "wall stuck". Points to note about differential pressure sticking are: (1) sticking is restricted to the drill collars, (2) the collars become stuck opposite a permeable formation, (3) the sticking occurs after an interruption of pipe movement, (4) circulation, if interrupted, can be restarted after the sticking is noticed, and (5) no large amounts of cuttings are circulated out after restarting circulation. Helmick and Longleyl investigated pipe sticking by differential pressure in the laboratory and found an empirical relationship between the differential pressure, the sticking time and the required pull-out force. In this paper an explanation of the mechanism is given based on Terzaghi's theory of clay consolidation. A qualitative description is given in the following paragraphs while the derivation of fonnulas is given in Appendices. This paper is a first attempt to explain pressure differential sticking and many points will require additional theoretical and practical investigation before the problem can be fully understood. PRESSURE DIFFERENTIAL STICKING AS A CONSOLIDATION PROBLEM In any borehole, where the mud pressure is higher than that exerted by the formation fluids, a mud cake is formed opposite the permeable sections of the hole and a continuous flow of filtrate takes place from the mud, through the cake and into the formation. This radial flow pattern requires a certain distribution of the hydraulic and the effective (grain-to-grain) stresses inside the mud cake. Any quantitative or qualitative change in the external pressure conditions will produce a change in the flow pattern and, consequently, also in the internal stress distribution inside the cake. In view of the low permeability and the high compressibility of a clay mud cake, the adjustment of the internal stress distribution is slow and is accompanied by a change in volume. Time dependent stresses are thus created which gradually diminish as the new state of equilibrium between internal and external pressures is approached. Some 30 years ago, Terzaghi developed his "Theory of Consolidation" to account for the time-dependent stresses and settling of clay formations under the influence of external loads. He derived a differential equation by which the time-dependent hydraulic stress and the consolidation can be computed for any point inside the layer during the consolidation process. His theory is based on the assumption that the change in stress is solely due to a change in water content and it may only be applied to one-dimensional consolidation phenomena. Other investiga-tors5,10 have expanded his theory to include processes of more than one dimension. The difference between the external pressures on the mud cake before and after sticking is a qualitative one (isolation of part of the cake by the static contact with the drill collars after pipe movement has been stopped)', and the time-dependent stresses thus created may be investigated by means of Terzaghi's theory. By this analysis the changes in the nature of the contact surface between the drill collars and the mud cake during the sticking can be explained; and the friction force between the two may be computed as a function of the sticking time, the borehole dimensions and the mud cake characteristics.

By R. L. Whiting, H. J. Ramey

The basic study from which this paper was prepared was started as the result of the growing need throughout the world for increasing quantities of energy in all forms. Quite obviously, natural forms of energy that are readily available at low development cost are those in greatest demand. The underdeveloped countries — and particularly those having little or no petroleum resources — are the countries in which the most interest is being shown in the newer energy sources. One of the least expensive energy sources is natural geothermal steam.'-* Although this form of energy has been recognized for centuries, it has been only during the past 20 years that serious efforts have been made to harness it. Natural geothermal steam energy in Italy, New Zealand, Mexico, Japan, and California is now being produced through wells to drive turbines and generate electricity. Further, active exploration for natural geothermal steam is being conducted in Hawaii, Fiji, Taiwan, Chile, Russia, Greece, and Katanga. It is surprising to find that most geothermal steam exploration is in the "steam seep" stage. That is, surface studies are made and exploratory wells are drilled in the general area of steam seeps. However, in the larger geothermal steam areas, there have been efforts to apply the most modern geological and reservoir engineering principles in order to define the reservoir parameters, particularly those relating to estimates of reserves and future productivity. This paper is concerned with the development of appropriate equations and techniques to facilitate these estimates. Production of natural steam or hot water presents problems different from those experienced in the production of oil and gas. For example, steam or hot water systems may be essentially single-component systems, while hydrocarbon systems are most frequently multicomponent fluid systems. Heat effects are much larger for water than for hydrocarbon systems; and the natural steam production may or may not be isothermal, while production of petroleum reservoirs is considered normally to be isothermal. Petroleum reservoir engineering principles may be applied to natural steam or hot water reservoirs if the inherent differences in the systems are considered. The basic considerations involved in geothermal steam reservoir engineering are: thermodynamics, physical and thermal properties of water, materials and energy balances, fluid influx, and performance matching and predicting. Thermodynamics Fig. 1 is a pressure-temperature diagram for the liquid-vapor region for pure water, showing the critical point and five other points representing possible initial conditions for a geothermal steam reservoir. To generate a physical appreciation for the mechanics of natural steam production, it is helpful to consider

Jan 1, 1970

By W. C. Lacy

The last crop of graduates from our colleges and universities who sought employment in the mineral industries found that they needed to hustle to find a job. There was no longer a list of waiting employers to choose from. Some of them became discouraged and drifted into other fields; many are still looking for employment. Word has gotten around that there are no jobs available in the mineral industries, and enrollment in the various colleges of mines and mineral industries has started to drop. Even established professional men are finding themselves suddenly out of work because of unstable metal prices and rising costs. All these people-students beginning to search for a career, young engineers not yet established-face the same problem: "What is the future of the mineral industries, and what type of training will best qualify the scientist or engineer for this changing field?" This question was posed to a number of leaders in different phases of the industry. Their comments are summarized as a guide to those considering a career in the finding, extraction, or beneficiation of mineral products.

Jan 1, 1960

By M. P. Tixier, K. S. Kunz

A method for the interpretation of temperature curves recorded in gas producing wells is described. One essen-tial feature of the method is a simple graphical construction which conveniently reflects the amount of gas flowing from a given producing formation. This method, applied in conjunction with the Induction Log and radioactivity logs, is valuable to determine the points of entry of gas and to estimate the over-all thickness of the producing zones and their respective contributions to the total production. The method in particular is helpful in evaluating the effect of fracturing operations. An outstanding result of the application of the method is to bring to the light the relative importance of sand-shale interfaces in the production of gas. The paper is illustrated with field examp1es. INTRODUCTION The electrical logging tools involving conventional systems are not applied in wells which do not contain water base mud (empty holes, or wells filled with oil base mud), because of the absence of electrical connection between the electrodes and the surrounding formations. It is, therefore, common practice in this case to use other methods which do not require the presence of a conductive fluid in the borehole: resistivity log with scratcher electrodes, Induction Log, radioactivity logs, temperature log. . . . Such conditions are encountered in some regions, as the San Juan Basin, N. Mex., where a technique of drilling gas wells, using gas as a drilling fluid, has been introduced in the last two years. By the middle of 1953, an appropriate method for the logging of these wells was devised on the basis of field tests and of theoretical studies. It is the purpose of the present paper to give a description of this method. In these wells the logging operations are performed during the process of gas production, so that the temperatures in the boreholes are strongly affected by the cooling due to the expansion of the gas. On the other hand, a special thermometer, with a high sensivity and a short time constant, has been recently made available, which has enabled much more detailed and accurate recordings of the borehole temperatures than with the conventional instruments. As a result of these two circumstances, the temperature log constitutes the essential element of the method, in making possible the detection of the gas producing zones, the definition of their boundaries, and the estimation of the respective contributions of each separate zone to the total production. The method also involves the radioactivity and Induction Logs, as auxiliary documents. These logs in the present instance are helpful in the determination of the reservoirs. However, the information they give in this respect is limited. This comes from the fact that, due to the absence of the MicroLog and/or MicroLaterolog and of the SP log, the estimation of formation factors and connate water salinities is somewhat conjectural. Furthermore, little help is obtained from the Neutron log for the evaluation of porosity and of formation factor because the variations of gas saturation affect the Neutron log in a way similar to the variations of porosity. It should be said also that even an exact knowledge of the gas saturation of the reservoir beds would not

Jan 1, 1956

H. S. COE, St. Louis, MO. (written discussion *)-I feel much gratified that Mr. Mishler has confirmed those principles of slime settlement expressed by Mr. Clevenger and myself. I wish to state that, when we wrote the article referred to by. Mr. Mishler we had not seen his earlier article in which he gave a formula to be applied to the settling rate off feed pulp for determining thickener area required at El Tigre. It has been my experience that in cyanide work the settling area required is determined by the settling rate of the feed pulp for perhaps 20 per cent. of all of the ores to be encountered. For the other ores, the area required is greater than that indicated by the settling rate of the feed and corre-sponds to the settlement of a somewhat thicker free-settling pulp. Mr. Mishler, in his paper, has thoroughly outlined a set of tests for determining thickener capacity, which, if carefully carried out, should be entirely reliable, provided allowance is made for changes in the mill feed from time to time. Two features of his paper, I, believe; need comment. In speaking of the time required for slime to flocculate after being fed, Mr. Mishler quite properly states that the actual settling rate for the feed pulp can-not be that of completely flocculated pulp because of this time lost in flocculation. It seems to me, however, that this feature cannot be of very great importance, for the following reason: The upper zones of pulp in a thickener may be, and often are, as thin as the feed pulp. If, therefore, the feed be introduced at sufficient depth below the pulp surface to prevent agitation at the surface, there will be ample time for it to become flocculated before it becomes the surface layer, and it, will

Jan 1, 1918

By R. H. Jacoby, V. J. Berry, R. C. Koeller

The experimental phase behavior of several field gas-condensate systems, one field volatile oil system, and a series of synthetic systems having gas-oil ratios from 2,000 to 20,000 scf/bbl stock tank oil was measured. The data were used to calculate the depletion performance of the field systems at their respective reservoir temperatures and of the synthetic systems at various temperatures. The results of the performance calculations were used to prepare correlations of total stock tank oil and separator gas in-place, and the amount of each recovered by primary depletion. Data needed to use the correlations are initial gas-oil ratio, initial tank oil gravity, reservoir temperature and reservoir pressure. The correlations presented should be useful for estiinating recovery from reservoirs producing volatile oils or rich gas condensates having gas-oil ratios from about 2,000 to 30,000 scf/bbl of stock tank oil. INTRODUCTION Prediction of depletion performance for gas-condensate reservoirs usually requires extensive laboratory work or lengthy phase-behavior calculations. For many small gas-condensate bearing zones the expense of such work is often not justified. Furthermore, where large holdings are involved, it is useful to have estimates of future oil and gas production in advance of the results of a laboratory analysis, even if such work is ultimately planned. For these reasons, it would be of value to have a method for rapidly estimating the depletion performance of gas-condensate reservoirs from the type of field data usually available. Few data on the reservoir depletion performance are available for the purpose of developing correlations. The increasing number of gas-condensate discoveries and the advent of high-speed computers have stimulated the development of methods for predicting performance. Such calculated performance data have been shown to be reliable and are becoming accepted as a basis for reserve estimates and for engineering studies. It therefore seems satisfactory to use results of performance predictions themselves for the purpose of developing the desired correlations. Such an approach is described in this paper. Several rich natural gas-condensate systems (gas-oil ratios of from about 3,600 to 60,000 scf/bbl) and one natural volatile oil system were studied (2,363 scf/bbl). In addition, to provide a more systematic basis for correlating purposes, a series of related, synthetic reservoir fluid mixtures was also studied (GOR's from about 2,000 to 25,000 scf/bbl). The purpose of this paper is to show how the recovery of oil and gas by primary depletion may be estimated from surface gas-oil ratio, reservoir temperature and pressure, and tank oil gravity. procedure Experiments Companion samples of gas and oil were collected from the high pressure separators in nine different fields at the time of their discovery. These samples were each recombined in accordance with the respective producing GOR to reproduce the reservoir fluids. Eight of these fluids, designated F-2 through F-9, were rich gas-condensate systems at the respective reser-

By John Henry Harden

It appears that in the earlier days of anthracite coal mining, 1824-25, the Lehigh region mined 76 per cent. of all the coal sent to market. During the same period Wyoming sent 12 and 5 per cent. respectively, whilst the Schuylkill sent 11 and 18 per cent., the number of tons marketed being in those days very small indeed. In the year 1828 the Schuylkill region mined over one-half of all the coal sent to market, and continued to do so for thirty years (with the exception of the year 1831), until 1858 ; since that date the production has declined very steadily in comparison with the other regions, until, in 1876, it was only 34 per cent. Wyoming, in the year 1820, was mining 40 per cent., but the production of all the regions was very small; in six years it declined to 5 per cent., increased to 34 per cent. in 1831, declined to 10 per cent. in 1838. Since which time the increase has been gradual, until 1873-75 Wyoming produced over 50 per cent. of all the anthracite coal sent to market. In 1867 the production exceeded that of Schuylkill, and has continued to do so since that time. In the year 1876, during the existence of the "coal combination," Wyoming lost 9 per cent.; during the same time Lehigh gained 7 and Schuylkill 2 per cent. over their relative production of the preceding year, the decrease of Wyoming being two and a half million tons, the increase of the Lehigh one million, the decrease of the Schuylkill nearly three-quarters of a million. The extraordinary production of the Lehigh region at a time of decreased demand and in opposition to an agreement with the other regions to limit the supply to the supposed demand mas the cause of the disagreement which ultimately broke up the combination of the great coal-producing and carrying companies. The Lehigh region produced very steadily, from 1829 to 1854, an average of about 22 per cent. of the whole production. From 1854

Some early production records of the early companies operating in the Deep River field are said to be still in existence, but the writer has been unable to find them. (Table 63.) [ ]

Jan 1, 1942

By John Henry Harden

IT appears that in the earlier days of anthracite coal mining, 1824-25, the Lehigh region mined 76 per cent. of all the coal sent to market. During the same period Wyoming sent 12 and 5 per cent. respectively, whilst the Schuylkill sent 11 and 18 per cent., the number of tons marketed being in those days very small indeed. In the year 1828 the Schuylkill region mined over one-half of all the coal sent to market, and continued to do so for thirty years (with the exception of the year 1831), until 1858 ; since that date the pro¬duction has declined very steadily in comparison with the other regions, until, in 1876, it was only 34 per cent. Wyoming, in the year 1820, was mining 40 per cent., but the production of all the regions was very small ; in six years it declined to 5 per cent., increased to 34 per cent. in 1831, declined to 10 per cent. in 1838. Since which time the increase has been gradual, until 1873-75 Wyoming produced over 50 per cent. of all the anthracite coal sent to market. In 1867 the production exceeded that of Schuylkill, and has continued to do so since that time. In the year 1876, during the existence of the " coal combination," Wyoming lost 9 per cent. ; during the same time Lehigh gained 7 and Schuylkill 2 per cent. over their relative production of the preceding year, the decrease of Wyoming being two and a half million tons, the increase of the Lehigh one million, the decrease of the Schuylkill nearly three-quarters of a million. The extraordinary production of the Lehigh region at a time of decreased demand and in opposition to an agreement with the other regions to limit the supply to the supposed demand was the cause of the disagreement which ultimately broke up the combination of the great coal-producing and carrying companies. The Lehigh region produced very steadily, from 1829 to 1854, an average of about 22 per cent. of the whole production. From 1854

Jan 1, 1877

By J. W. MacDonald

Review of equipment, performance, and shaft design plans including head-frames for sinking and forms for lining are given. Also included are comparative data for shafts of 11 x20 ft and 193/4 x 30 ft with 756 and 666-ft depths, respectively. Advantage from curtain wall installation with "slip forms" which warrant consideration for normal lining are outlined. A preliminary review is also made of "chemical grouting" to stop water inflow leakage with Halliburton equipment and service. Two coal mine shafts recently completed in Franklin County, Ill., afford experience and accomplishment to warrant review. These shafts provide access to a tract with a potential recovery of one hundred million tons. This work provided the initial sinking by other than a contractor's organization since 1918. Four additional shafts required during the interim were sunk under contract arrangement with others. Supervisory contact and inspection afforded experience to govern planning and conduct of the recent work. TEST DRILLING Core test holes were drilled within each of the two shaft locations. Four additional cable tool holes were drilled on a radius of 700 ft from the shaft bottom to determine the coal seam elevations and govern the underground layout plans for each shaft. A graphic log of the hoist shaft test drillhole is shown by Fig. 1. A very soft sandstone was found at a depth of 16 ft. Cored recovery of the sandstone proved much weaker than the overlying compacted sand secured with coring facilities for soil recovery. Gradation from the very soft sandstone to fairly hard material occurred with the next 14 ft, extending to a depth of 30 ft. The weak character within the upper portion entailed need of adequate protection when sinking as described later. A part of the sandstone provided sufficient porosity and permeability to warrant further investigation. Adjacent cable tool drilling for temporary water supply disclosed inflow was limited to 2 gpm with a depth of 40 ft. It was increased to 12 gpm during the next 50 ft of drilling and occasioned subsequent precaution when sinking. General arrangement of facilities for sinking the hoist shaft is shown by Fig. 2. An available steel frame building was used to accommodate the hoist, compressor, shop, and shower or change room. The stiff leg derrick with 90-ft length of boom permitted removal of forms from the wood shop to the storage area or delivery within the shaft. Reinforcing steel and other needs were similarly handled, in addition to headframe erection. The headframe was placed over one end of the shaft to enable passage of forms for lining through the adjacent half next to the stiff leg derrick. The steel headframe as shown by Fig. 3 was fabricated locally. Side anchored cables from the

Jan 1, 1961

By E. W. Codington

The pebble-phosphates of Florida occur in a district roughly bounded on the north by the 28th parallel, on the east by an irregular line running a few miles east of Peace river and on the west by the Gulf of Mexico, and covering an area of about 4000 square miles. There seems to be no reason why the deposits should not extend farther south along the gulf coast. That section remains unprospected, transportation-facilities being non-existent. It is not intended in this paper to discuss the geology of these formations; but a word as to their probable origin will be perhaps the best method of giving a correct idea of their present position. Starting with a low, flat surface, with even less of superficial undulation than appears at present, an im-

Jan 1, 1896

By H. T. Matson

IN the Northern Rhodesia copper fields the size of the orebodies and the exceptionally consistent values over great distances made it possible to outline the ore with drill holes spaced at 1000-ft. intervals; in some cases, 2000-ft. intervals.. Owing to the fact that the size of the deposits made it very evident that much outside capital would have to be called in to develop them and, owing to the wide spacing of the holes, it was essential that the sampling of drill holes be as accurate as possible, so that outside examining engineers could adopt the results as trustworthy within the limits of accuracy of the drilling method. With this object in view, the field staffs of the Selection Trust group of companies have studied for the past three years, and are still studying, drill sampling in a very thorough manner, and for this reason it is felt that these notes may be of interest to engineers or students who are, or in the future may be, in charge of drilling operations. The orebodies in this field lie in shales and sandstones, more or less indurated, in the lower strata of the Roan series, and the copper mineralization is in the form of sulfides predominantly, with some oxidized copper minerals. Those interested in the geology and history of the area can find full details in a recent paper by Anton Gray and Russell J. Parker.1

Jan 1, 1930

By Ganesh P. Mohanty, James J. Wert

THE brittleness of the intermetallics usually render their deformation studies at ordinary temperatures using conventional techniques inadequate. On the other hand, although X-ray line broadening measurements is not a complementary technique, it provides a means for gaining limited but useful information on the cold worked state of these materials. In the present instance, a study of the effects of cold work in the lead telluride intermetallic compound was carried out by analyzing the diffraction profiles of the deformed and the corresponding annealed samples. An ingot of PbTe was prepared by induction melting high-purity lead and tellurium in a quartz crucible under an atmosphere of argon. After homo-genization, the ingot was ground to -325 mesh at room temperature, and using a polished die the cold- worked powder was pressed into the form of flat faced briquets for diffraction measurements. A spectrometer with 0.125 deg per min scanning velocity, CuKa radiation, pulse height analyzer, and a proportional counter were employed in the X-ray measurements, and the powder peaks were collected from the sample in fully cold-worked state and after it had been annealed to relieve the effects of cold work completely. For reliable estimates of the peak extremities, small angular ranges where the tails merged into the background were point counted. Fourier inversions of the experimental peaks were carried out in an IBM 705 computer using the procedures introduced by stokes.' Both the cosine and sine components of the Fourier series were used to take into account any peak assymetry arising

Jan 1, 1963

By Edward H. Robie

OF the current Adirondack iron mine development, the Benson Mines operation of the Tones and Laughlin Ore Co. (Jones & Laughlin Steel Corp. wholly owned subsidiary) is the last to go into operation. Following an active construction program in 1943, the mine. concentrator and sintering plant were scheduled to enter production in the fall. This description therefore cannot include any operating data, and details of equipment and flowsheet have not as yet been released.

Jan 1, 1943

By Richard P. Rothwell

Though coal has been mined in this country for more than a century, no systematic effort was ever successfully made to ascertain the total amount produced. The production of the Cumberland Basin, Md., and the shipments from the anthracite fields of Pennsylvania, have been placed upon record, thanks to the intelligence and foresight of Mr. C. Slack in the former case, and to the late Mr. B. Bannan in the latter. For some of the years between 1822 and 1842, the production of the Richmond Basin was reported by Mr. R. C. Taylor, but since that date till the author undertook this work it was impossible to obtain any statement of the production of this field. A few of the newer fields, such as that of Mt. Diablo, Cal., have been fully reported, and a few of the newer States have also had this service performed by some intelligent private individuals; but no statistics of coal production have ever been collected either by the State or General Government, if we except the returns for the years 1869—70 of the census report. During the year 1875, by great exertions, I succeeded in obtaining, and July 3d, 1875, gave in the Engineering and Mining Journal what, " though not an accurate statement of our coal production," was " by far the most full and reliable that had ever been published." Though that report showed the production of bituminous coal to be 23,630,094 gross tons, or about six million tons more than had ever before been reported, it was in reality two and a half million tons below the actual output. The more full returns I obtained for 1875 gave many figures for 1874

By T. G. R. Rawlins, L. E. Brosselard

Direct platinum carbon replicas have been used to study substrates prior to growth and after initial nu-cleation of the layer. Replicas have been directly stripped and correlations have been made with other replica techniques. Mechanically polished substrates are very flat with occasional areas of "dirt", which is apparently silicon. When such substrates are etched in hydrochloric acid gas, scratches and hexagonal defects (thought to be polishing compound) are revealed, together with areas of apparent redeposition. Chemically polished substrates are much less flat although much more homogeneous in appearance. Heat treat)nents have no effect. Nuclei deposited on these surfaces, using a normal silicon tetrachloride system, have been examined. Nuclei on mechanically polished subsrates occur in random areas only, whereas on chemically polished surfaces they are more uniformly distributed. THE interest in the study of thin films and now their rapidly expanding use in many fields has increased over a period of years. Much of this current interest, particularly in the field of single-crystal or epitaxial thin films, has derived its stimulus not only from possibilities for application but also from fundamental electron-microscope studies which have indicated the manner of growth of such layers from the initial nuclei.1-5 Previous work involving study of growth processes may be divided into three categories. First, vacuum deposition, primarily of metals, on a variety of substrates has been studied by electron microscopy and electron-diffraction techniques. These have shown the three-dimensional aspect of nucleation and the remarkable liquidlike behavior of the growing nuclei which coalesce to form a complete layer. More recently this work has been expanded in two ways: by growth inside the electron microscope this has obvious advantages for kinetic studies; and by growth in ultrahigh vacuum—much of this work has been done on semiconductors.8-11 It is of interest to note that metals, specifically gold deposited on rock salt, will form only polycrystalline layers in ultrahigh vacuum unless the substrate surface is contaminated.12 In general the mode of growth for vacuum-deposited semiconductor films is the same as that for metal films. The second method of growth that has been studied is that of electrodeposition.13,14 The little that has been published suggests that the mode of growth is similar to the vacuum case, except that irregularities may perturb the electric field and disturb the growth process. The third and last primary method of growing epitaxial layers is by use of chemical methods. These techniques have generated much interest and much has been published on them. Considerable electron-microscope work has been done on the defects in the layers; however comparatively little work has been undertaken on the initial nucleation and early stages of growth. Confining ourselves now exclusively to the case of silicon, Charig et a1.15 have considered the growth of silicon on silicon substrates by hydrogen reduction of trichlorosilane, and studied the films by means of replica and transmission techniques. Subsequently they have studied the same system for growth on quartz,16 and with the addition of pyrolysis of silane on quartz and alumina.17 Also Manasevit el al. have studied deposits using silane and silicon tetrachloride on sapphire.18-14 Finally, in this volume studies of deposition on beryllia and sapphire are reported. Although Revesz and Evans20 have examined complete layers, grown by means of the widely used silicon tetrachloride reaction, no detailed examination similar to that published by Charig and Joyce21 for the trichlorosilane system has been given. Therefore this investigation has examined substrate surfaces prior to growth and then nucleation on these surfaces for the silicon tetrachloride system. EXPERIMENTAL In this work the surfaces have been studied by means of standard replica techniques. Because of the very real problems associated with artifacts introduced,22 different replicas and different cleaning

Jan 1, 1967

By C. E. Shoenfelt

There was a notable decrease in drilling operations in 1940 in all of the Rocky Mountain states except Montana, where the two large fields on the Canadian border, Cut Bank and Kevin-Sunburst, were espe-cially active. The expanding markets for Montana natural gas made necessary the more intensive development of such fields as Rowdoin, Cedar Creek and Devon. While there were no important oil and gas discoveries in 1940 in any of the Rocky Mountain states, a few small pools were opened, which may constitute separate areas but may prove with later development to be extensions of old fields. Some of the old fields were extended and deeper pay zones were discovered in others. These have given the areas greatly increased oil reserves and therefore are just as important as the discovery of new fields. The more important of the developments in 1940 are given, by states, in the following paragraphs. Colorado Hiawatha Field, Moffat County.—The Mountain Fuel Supply Co. began the development at Hiawatha of its oil reserves, which were discovered in about 1929, and late in the summer oil began moving from the field by truck to the shipping point at Rock Springs, Wyoming. The Hiawatha field of northwestern Moffat County was discovered in 1927 by the Sormir Petroleum Co., with the completion of No. r Florence Wilson for 4,5,000,000 cu. ft. of gas a day from a Wasatch sand lens at 2200 it. In later development of the field, oil showings were reported in several wells but no development of this resource was undertaken until 1940, when a test of the oil possibilities was started with the release in April of a location for No. 5-A Wilson on the S\W. SW. NW. of sec. 23-1zN-1ooW., on the east side of the field. The Well had an initial production of 327 bbl. of oil a day pumping from three Wasatch (Tertiary) sands between 2005 and 2540 ft. It was drilled to 2562 ft., where the 65/8-in. casing was cemented and gun-perforated at 2005 to 2125 ft., 2260 to 2335 ft. and 2513 to 2540 ft. At the end of the year, this well was averaging zoo bbl. of oil per day, pumping. Two other wells were drilled for oil on Hiawatha during the summer—one a small well of 60 bbl. per day and the other a small gas well. Powder Wash Field, Moffat County.—The development of the Powder Wash field in northwestern Colorado was resumed in 1940 by the Mountain Fuel Supply Co., with the release of a location for No. 2-A Musser in the CWL.NW.SE. of sec. 4-1rN-97W. The Powder Wash field was discovered in 1931 by the Mountain Fuel Supply Co. and the discovery well, No. I Musser, on C.NW. of sec. 5-IIN-97W., was completed at 2152 ft. in the Hiawatha member of the nonmarine Wasatch for-mation for an open flow of 34,000,000 cu. ft. of gas per day under a natural pressure of 685 lb. per sq. inch. Oil was discovered in the Powder Wash field on Nov. 26, 1936, in the company's No. I Carl Allen on the NE.SW.SE. of sec. 32-12N-97W. The oil production was

Jan 1, 1941

By C. E. Shoenfelt

There was a notable decrease in drilling operations in 1940 in all of the Rocky Mountain states except Montana, where the two large fields on the Canadian border, Cut Bank and Kevin-Sunburst, were espe-cially active. The expanding markets for Montana natural gas made necessary the more intensive development of such fields as Rowdoin, Cedar Creek and Devon. While there were no important oil and gas discoveries in 1940 in any of the Rocky Mountain states, a few small pools were opened, which may constitute separate areas but may prove with later development to be extensions of old fields. Some of the old fields were extended and deeper pay zones were discovered in others. These have given the areas greatly increased oil reserves and therefore are just as important as the discovery of new fields. The more important of the developments in 1940 are given, by states, in the following paragraphs. Colorado Hiawatha Field, Moffat County.—The Mountain Fuel Supply Co. began the development at Hiawatha of its oil reserves, which were discovered in about 1929, and late in the summer oil began moving from the field by truck to the shipping point at Rock Springs, Wyoming. The Hiawatha field of northwestern Moffat County was discovered in 1927 by the Sormir Petroleum Co., with the completion of No. r Florence Wilson for 4,5,000,000 cu. ft. of gas a day from a Wasatch sand lens at 2200 it. In later development of the field, oil showings were reported in several wells but no development of this resource was undertaken until 1940, when a test of the oil possibilities was started with the release in April of a location for No. 5-A Wilson on the S\W. SW. NW. of sec. 23-1zN-1ooW., on the east side of the field. The Well had an initial production of 327 bbl. of oil a day pumping from three Wasatch (Tertiary) sands between 2005 and 2540 ft. It was drilled to 2562 ft., where the 65/8-in. casing was cemented and gun-perforated at 2005 to 2125 ft., 2260 to 2335 ft. and 2513 to 2540 ft. At the end of the year, this well was averaging zoo bbl. of oil per day, pumping. Two other wells were drilled for oil on Hiawatha during the summer—one a small well of 60 bbl. per day and the other a small gas well. Powder Wash Field, Moffat County.—The development of the Powder Wash field in northwestern Colorado was resumed in 1940 by the Mountain Fuel Supply Co., with the release of a location for No. 2-A Musser in the CWL.NW.SE. of sec. 4-1rN-97W. The Powder Wash field was discovered in 1931 by the Mountain Fuel Supply Co. and the discovery well, No. I Musser, on C.NW. of sec. 5-IIN-97W., was completed at 2152 ft. in the Hiawatha member of the nonmarine Wasatch for-mation for an open flow of 34,000,000 cu. ft. of gas per day under a natural pressure of 685 lb. per sq. inch. Oil was discovered in the Powder Wash field on Nov. 26, 1936, in the company's No. I Carl Allen on the NE.SW.SE. of sec. 32-12N-97W. The oil production was

Jan 1, 1941