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By Joseph E. Pogue

The outstanding features of 1926 in the petroleum industry included the following: 1. Stocks of all oils (crude and refined) were reduced, making the first annual decline since 1918. 2. Domestic crude oil production increased steadily during the last 11 months of the year, accelerating during the fourth quarter, and ending the year at the highest level ever attained. 3. Three new major oil fields were developed—Panhandle, Spindle-top and Seminole. 4. Important advances were registered in production technique, tending to retard the declines of old wells and to maintain the flush periods of new wells. 5. The problem of gaining greater economic control of production through unit operations and gas conservation received growing recognition by the industry and the Federal Oil Conservation Board. 6. The rate of drilling was sharply increased during the second quarter of the year and suffered only a very slight retardation during the closing months. 7. The runs of crude oil to stills were maintained above normal throughout the year and underwent acceleration during the fourth quarter. 8. The gasoline situation was marked by a continuous and substantial increase in the rate of production of cracked gasoline, and by an improvement in the statistical position of the commodity. 9. Prices of both crude petroleum and its principal derivatives were characterized by more profitable levels and greater stability than for a number of years past; and, while showing declines during the fourth quarter, prices did not recede sufficiently to slow down materially either drilling or refinery operations. Change in Stocks The keynote of 1926 was a reduction in stocks of all oils to the extent of approximately 24,000,000 bbl., or 4.4 per cent., of which roundly

Jan 1, 1927

By William M. Bowron

Thirty years ago, when I stood on the cliff of red fossil iron-ore, on Red mountain, Jefferson county, Ala., I asked what were the geological relations of this remarkable deposit. In reply I was told that it was a limestone, colored and saturated by some unknown but wholly external influences, and that at a reasonable distance from the surface the color would disappear. I could find no satisfactory explanation, either of the nature of this wonderful external permeating influence, or of the cause of such a ferrous impregnation selecting this one particular bed of limestone, to the exclusion of the higher and lower beds of the same material which are not even stained. I. The Present Theory. Referring to this subject, Dana says :' "The clays, clayey sandstones and limestones of the Clinton epoch, through New York and the Appalachians, show that the mud-flats and sand-banks, and hence the shallow seas of the coast region, still continued.... The beds of argillaceous iron-ore, which spread so widely through New York and some of the other States, west and south, could not have been formed in an open sea; for clayey iron-deposits do not accumulate under such circumstances. They are proof of extensive marshes, and, therefore, of land near the sea-level. The fragments of crinoids and shells found in these beds are evidence that they were, in part at least, salt-water marshes, and that the tides sometimes reached them." At first, this explanation seemed satisfactory, but the more I studied the ore the less satisfying the explanation became. 1. In the ore itself, I found associated with the small particles of rounded matter (now consisting of iron oxide in which organic structure, if ever present, has become lost, though the

Jan 1, 1906

By Allan M. Hale

The paper discusses past trends in phosphate reclamation, indicating advantages and disadvantages of land and lakes, sand tailings capped with overburden, phosphate slimes capped with overburden, and overburden fill reclamation. In addition, new techniques of reclamation such a clay settling-pond disposal and wetland restoration are discussed.

Jan 1, 1983

By R. W. Raymond

ALEXANDER BRINTON COXE was born in Philadelphia, Pa., Jan. 19, 1838, the second of five sons of lion. Charles Sidney Core and Ann Maria Brinton. A more extended history of his family and its important relations to the development of the United States will be found in my Biographical Notice of his younger brother, Eckley B. Coxe, published in 1895. It is therefore sufficient to say here that Dr. Daniel Coxe, a distinguished physician and surgeon of London, and a medical attendant of Charles II and Queen Anne, purchased, in 1684 and 1686, lands in East and West Jersey from grantees of the Duke of York, and became Governor of West Jersey, in which capacity he did much to develop the provincial fisheries, the manufacture of marine salt and pottery, the exportation of tim¬ber and the West India trade. In 1698, having acquired the royal patent of the Province of " Carolana," covering (with some reservations) the territory extending from the Atlantic to the Pacific, between the 31st and 36th parallels of N. latitude, Gov. Cole sent an expedition from Charleston, S. C., to the Mississippi. In 1769, seventy years later, his grandchildren surrendered to the Crown their title under this vast and vague patent, receiving in return a grant of 100,000 acres in the Colony of New York. The line of his descendants, so far as they concern this sketch, is as follows 1. Col. Daniel Core, his son, b. 1673, who came to New Jersey in 1700; resided there until his death (1730); held many high offices; and issued in London (1722) A Description of the Provinces of Carolana, containing probably the earliest published plan of political union for the British Colonies in North America.

Sep 1, 1906

By H. E. Cline, T. H. Alden

A study zvas made of rate-sensitive plastic deformation and superplasticity in alloys of lead and tin. These alloys (lead, PO-19 pct Sn, Sn-38 pct Pb, Sn-2 pct Pb, tin) were extruded, aged at room temperature, or melted and resolidified to produce a variety of ~nicrostrnctures. Flow stress us strain rate data were obtained frorn tension tests for strain rates between 10-6 and 1 min-1. The curve log o .us log £ was S-shaped jor fine-grained materials and approxinzately linear for coarse-grained nzaterials. At constant grain size, the behavior was relatively insensitive to conposition. High rate sensitivity (d log o/d log k) and superplasticity occurred at intermediate strain rates in fine-grained materials and are believed to be associated with a transition with strain rate in the mode of plastic flow. This transition was shifted to higher strain rates with increasing temperataire or decrensing grain size. The high rate rneclzanisrn is presunzed to be slip, while rnetallographic evidence sug-gests that the low rate lnechanism is pain boundary sliding. PEARSON' discovered that extruded eutectic alloys of Pb-Sn and Bi-Sn could be elongated as much as 2000 pct in tension. The ability for stretching decreased with aging time or annealing to increase the grain size. At high strain rates, or if the material was in the cast condition, normal ductility was observed. Following deformation of the extruded Pb-Sn eutectic at low rates, Pearson observed an equiaxed granular structure on an initially flat surface, while rapid straining produced elongated grains. He attributed the large deformation in the extruded alloys to the persistence of extremely small grains to a temperature sufficiently high for inter granular flow. Avery and backofen2 measured the strain rate sensitivity of the flow stress, m = d In old In 6, in the Pb-Sn eutectic and established a correlation between m and the tensile elongation. In the extruded eutectic alloy the strain rate sensitivity was 0.1 to 0.2 at rapid rates and the elongation was small, while at low rates m increased to 0.4 to 0.6 and superplastic elongation was observed. They also noted a grain size effect. In the case of the cast Pb-Sn eutectic the strain rate sensitivity remained at 0.1 over the range of strain rates of their experiment (3 x 10"3 to 2 min-I). These authors suggested that diffusional (Nabarro-Herring) creep was the mechanism by which deformation occurred at low strain rates, while climb-controlled creep occurred at high rates. Two predictions of this model are that, at low strain rates, the strain rate sensitivity approaches 1, i.e., Newtonian viscosity, and that the strain rate at constant stress varies as D/L2, where D is the coefficient of self-diffusion and L the grain size. More recently, a mechanical and microstructural investigation of the dilute superplastic alloy, Sn-5 pct Bi, has been done.3 The results show that the high strain rate sensitivity is associated with a transition with strain rate of the mechanism of plastic flow. At low strain rates, grain boundary sliding and its associated accommodation processes were evident, while at high strain rates quasi-uniform slip was concluded to be the dominant deformation process. The following experiments were performed to extend our knowledge of the phenomena of superplasticity to a larger range of strain rates, compositions, temperatures, and microstructures in the Pb-Sn alloy system. The question of why a cast structure does not exhibit viscous behavior although it appears to have a fine microstructure2 was investigated.

Jan 1, 1968

By V. Kondic, W. M. Rumball

HUNT and Jackson' have recently suggested that binary eutectics might be classified according to the entropy of fusion of the component phases. Such a classification was in fact proposed2 some time ago by the authors and the purpose of this communication is to present some supporting evidence. As pointed out by Hunt and Jackson' typical metals of low entropy of fusion, ?S, tend to form normal eutectics (using Scheil's terminology3). Where one phase is metallic (low ?S) and the other nonmetallic (high AS) then anomalous structures are formed. These anomalous structures may either be regular (e.g., Bi-Sn)or irregular (e.g., A1-Si). Finally Hunt and Jackson suggest that where both phases are of high ?S regular faceted structures are formed. In the proposed classification2 the ratio of the entropies of fusion is taken as the quantitative parameter, i.e., ?Sa/?SB = E, where e > 1.0. An extensive literature survey has been carried out2,4 for reliable photomicrographs of eutectic structures. The structures, numbering 151, have been classified into two classes, viz., normal (i.e., lamellar and rodlike) and anomalous. The latter group has been arbitrarily subdivided into regular and irregular anomalous eutectics. Details and sources of the structures are given elsewhere.2,4 In the absence of better thermodynamic data the value of E has been determined for each of the systems making the following assumptions and approximations: l) The entropy of fusion of solid solutions may be calculated additively;5 ii) Inter metallic compounds are treated similarly but with the addition of the following term for fully ordered structures.5 -4.573(Ni lOg10 Nl + N2 log10 N2) where Nl and N2 are the atomic fractions. It might be argued that the entropies of fusion are meaningless as the eutectic phases form at some temperature (T,°K) below their true melting point (Ta or Tb). As AS, = Lo/To if La the latent heat of fusion of a, is assumed independent of temperature, the actual entropy change AS& is given by La/Te. The ratio of entropies of fusion then becomes Fig. 1 shows E' plotted against cumulative totals for normal and anomalous systems from which it is seen that normal eutectics predominate at low values of E'; e.g., some 90 pct of normal systems lie below E' = 1.5 with 65 pct of anomalous systems above this value. Fig. 1 also shows that the regular anomalous structures occur mostly at low values of c' possibly suggesting growth more akin to normal than anomalous growth. The choice of c as a classification parameter was based on nucleation concepts, it being observed that metals widely separated in Sundquist and Mondolfo's8 nucleation series were anomalous and those close together normal. The basis of these classification views is really outside the intended scope of this communication but it is hoped to explain them fully in the near future.7 Having arrived at this entropy of fusion classification by nucleation considerations it is interesting to note that Hunt and Jackson's ideas are based on growth considerations. Elsewhere one of the authors4 has shown that an even better classification of the metallographic structures reviewed is obtained from purely conventional heterogeneous nucleation concepts. It has been found that systems having a value of the parameter +b less than 0.28 are almost certainly normal and above this anomalous: V, is the gram atomic volume. This parameter is nevertheless closely related to c and c', these being an approximation of p. The parameter is also related to the other classification3,8,9 which have met with any success in the past. All these classifications are to be reviewed shortly by the authorsU7 A significant thing about the classifications based on

Jan 1, 1968

By W. S. Hyler, W. L. Bruckart

The powder metallurgy and arc-cast types of wrought molybdenum stock were studied in rotating beam fatigue. Endurance ratios of unnotched specimens after 5x10 cycles were found to be 0.74 and 0.81, respectively. Fatigue notch factors (K,) of 1.36 and 2.05, respectively, were obtained on V-notched specimens having a theoretical stress-concentration factor Kt = 3.1. MOLYBDENUM and its alloys are rapidly gaining importance as engineering materials of construction for high temperature applications. AS a wrought material, molybdenum and its alloys are outstanding above 1800°F. It is necessary, however, with molybdenum to provide elevated temperature oxidation protection. This is currently being studied by a number of investigators. Thus far, there have been no published data on the fatigue behavior of molybdenum either at room temperature or at elevated temperature. The knowledge of fatigue behavior, particularly notched fatigue behavior, becomes increasingly important as the engineering importance of a material increases, especially from the design standpoint. The work described here was directed toward determination of the notched and unnotched rotating beam fatigue characteristics of molybdenum at room temperature. Also, it was desired to learn whether any difference exists between wrought molybdenum of the powder metallurgy and the are-cast types. Fabrication History of Bar Stock For this work, bar stock was procured from Climax Molybdenum Co. (are-cast type) and from Westing-house Electric Corp. (powder metallurgy type). The processing histories of these materials are listed in Table I. The first lot of are-cast molybdenum was deoxidized by aluminum additions. The second lot was deoxidized by carbon." Both lots of the powder Microstructure A microscopic examination of these materials, as received, revealed the powder metallurgy molybdenum to be free of inclusions and to be finely fibered. On the other hand, the are-cast C molybdenum possessed numerous carbide inclusions, and the arc-cast A appeared to have coarse grained fibers. These are shown in Fig. 1. Owing to the large apparent difference in fineness of fiber between the are-cast A and the powder product and are-cast C, a check was made of the recrystallized grain sizes to determine whether these differences persisted. A series of recrystallization anneals revealed mixed grain sizes in both the are-cast A and the powder product. Variations in grain diameter of as much as 50 times were found after full recrystallization at 1200°C for 30 min. There was no distinction between the two. Arc-cast C was not checked. Room Temperature Mechanical Properties Prior to subjecting the materials to fatigue tests, room temperature mechanical properties were determined. These data, together with the tensil: strength of the notched bars, data,togetherare listed in Table tensil: There were no significant differences in the tensile strengths of the two types of molybdenum. However, the powder metallurgy material was generally more ductile and yielded at a somewhat lower stress than the arc-cast material. Tensile strengths of the notched specimens indicated a slightly greater notch strengthening effect in the are-cast C than in the powder product, lot 2. Room Temperature Fatigue Properties Sample Preparation: Specimens were prepared for use in R. R. Moore rotating beam fatigue machines. These specimens had a continuous radius test section with a minimum diameter of 0.260 in. The specimens were prepared by grinding to shape and polishing to produce a smooth unworked surface. Polishing consisted of rotating a disk in the continuous radius section on which were attached, successively, emery belts of 240, 400, and 600 grit. The specimens were slowly rotated during the operation. The belt speed was high, and rotation was such that polishing scratches were longitudinal. Unnotched Fatigue Properties: Unnotched fatigue data were obtained from a number of specimens of each of the four lots of molybdenum. The results of the tests are presented in Fig. 2. From this figure,

Jan 1, 1956

By Jacob Reeese

I HAVE discovered a new method by which steel and other metals may be burnished by the automatic action of the burnishing machine, and by which the cost is greatly diminished, and more perfect work produced. And in addition to the polishing and burnishing action of

Jan 1, 1881

By Jacob Reese

I have discovered a new method by which steel and other metals may be burnished by the automatic action of the burnishing machine, and by which the cost is greatly diminished, and more perfect work produced. And in addition to the polishing and burnishing action of

Jan 1, 1881

THE Institute conducts jointly with the American Society of Civil Engineers, American Society of Mechanical Engineers and American Institute of Electrical Engineers, certain activities as listed below, and is joint owner with them of certain properties situated at 29 W. 39th St. in New York.

Jan 1, 1946

Extractive Metallurgy Division Institute of Metals Division Iron and Steel Division OFFICERS AND COMMITTEES John Chipman, President W R Hibbard, Jr, Past President C C Long, Vice-President T D Jones, Treasurer R W Shearman, Secretary AIME, 29 West 39th Street New York 18, N Y

Jan 1, 1959

EUGENE WESLEY SHAW,* Washington, D. C. (written discussion?).-Mr. Requa's subject is one of great economic importance, yet relatively new, and he has been able to combine extensive practical experience with the talent of grasping the broad features of a problem that has many discordant details.

Jan 5, 1918

A MINING institute open to all men interested in any branch of the mining industry will be held at the Col-lege of Mines, University of Washington, Seattle, during the week beginning March 5. Prospectors, miners, mine owners, persons interested in metallurgy, investors in min-ing enterprises, and the public generally are invited to at-tend. This institute will take the place of the Winter Min-ing Session which originated at Seattle in 1897 and con-tinued for twenty-eight years. The complete new equip-ment of the Mines Laboratory will be used to give demon-strations of new machines and processes of mining, ore dressing, and metallurgy. This year the ceramic industry, including cement and branches of clay working of special Importance in the Northwest, will be included in the insti-tute. All instruction will be given by specialists. Prominent technical men and managers will give lectures on their special subjects. Among the speakers engaged are G. T. Jackson, formerly superintendent of the Alaska-Gas-tineau and the Chichagof mines, who will speak on the mining of large bodies of low-grade ore; R. F. McElvenny, superintendent of the Tacoma Smelter, on the nature of contracts that a smelter can offer to mines and prospects; M. D. Leehey, mining lawyer, on some popular errors re-garding the mining law; H. H. Townsend, on the explora-tion and purchase of prospects by operating companies; J. L. McAllen, on quartz mining in the Willow Creek dis-trict, Alaska; F. Powell, on gold dredging. In the evenings, lectures illustrated by stereopticon views and moving pic-tures will be given. The week will close with an excursion o mines and plants.

Jan 3, 1928

The problems associated with the processing of the Tilden ore are very much representative of the problems encountered in plants processing fine grained magnetic and nonmagnetic iron ores. I would like to comment on some of the problems mentioned in Dr. Nummela'spaper and add to his list of research opportunities in the processing of iron ores. Grinding, the most important step in the processing of fine grained iron ores, is synonymous with liberation. One grinds to separate discrete grains of minerals from the gangue. By convention- al grinding in tumbling mills, mostly random size reduction is achieved with relatively little preferential liberation of minerals. Not only are discrete particles broken that should not be broken, but damage is done to the mineral surfaces. The combination of over- grinding and surface damage shows up in lower recovery figures and higher grinding costs. What is obviously needed is a better comminution process that is more discriminating and that would permit liberating mineral particles at the coarsest possible size with a minimum production of fines. Laboratory attempts at such preferential grinding have been quite successful, but technological difficulties have unfortunately prevented its use. Impact grinding is a good example of a new comminution process that has not been accepted because of equipment problems. Either these problems have to be solved or new comminution systems have to be developed to reduce grinding costs and improve liberation. In his paper Dr. Nummela mentions the change in the primary mill throughput that occurs during the winter months. Seasonal changes in the operation of the grinding circuit and other unit operations have been observed in many plants, and many explanations for this phenomenon have been advanced. The fact is that we do not fully

Jan 1, 1979

Discussion of the paper of L. C. Graton and Joseph Murdoch, presented at the New York Meeting, February, 1913, and printed in Bulletin No. 77, May, 1913, pp. 741 to 797. THOMAS T. READ, New York, N. Y. (communication to the Secretary *) :-At the meetings of English technical societies it not infrequently happens that, during the discussion of a paper, someone will arise to say that although he highly appreciated the material presented, nevertheless he believed it would have been better if some other phase of the question had been more highly emphasized. Assuming that this form of discussion is permissible in the Institute, I should like to reiterate the point made by Prof. A. J. Moses that conclusive proof of the identity of the minerals in question is an essential feature of the study of ores in this way. This is also expressed by Paul Krusch in his recent valuable paper 1 on the sulphide ores (in which he arrives at conclusions diametrically opposed to those of Mr. Graton), as follows : ?The diagnostic properties of the various ore minerals are known to but a limited circle of investigators." Many earlier investigators began the study of ores beneath the microscope by reflected light, but discontinued their work, in most cases, because they were unwilling to undertake the great amount of preliminary work necessary to securely establish a basis for their inferences. It is evident that Messrs. Graton and Murdoch realize that the promised later paper on diagnostic characters will be the more important of the two, but the point should be emphasized to forestall a flood of literature from other investigators who may gain the impression that the brief survey of polished specimens is a wade mecum to incontrovertible conclusions as to any given ore deposit.

Jan 10, 1913

By R. W. Cahn, C. D. Graham

Two predictions of the oriented growth theory of recrystallization textures have been tested by measuring the orientation dependence of the rate of growth of a single grain into a strained single crystal of aluminum, and determining the orientations of artificially and spontaneously nucleated grains growing preferentially into strained aluminum single crystals. Growth rates are found to be insensitive to orientation, except that new grains with orientations similar to the matrix or to a twin of the matrix have very low mobilities. Similarly, new grains growing preferentially into a strained crystal have random orientations, except that orientations near that of the matrix or its twins are avoided. The predictions of oriented growth theory are thus not confirmed. BASICALLY, the oriented growth theory of re-crystallization textures1 rests on the assumption that the rate of growth of a recrystallizing grain depends strongly on the orientation of the growing grain relative to the strained matrix into which it grows. In particular, the theory holds that in face-centered-cubic metals the orientation which corresponds to maximum growth rate is one in which the growing grain and the matrix are related by a rotation about a common <111> direction. The amount of rotation, as derived from several kinds of experiments,2-1 has been assigned various values, generally in the range between 20" and 40". (A <111> rotation of 60" is a twin relationship.) The conclusion that boundary migration rates depend strongly on orientation is based almost entirely on indirect evidence; there have been very few direct measurements of boundary migration rates as a function of orientation.* " The present investigation was undertaken to provide such measurements, to help make possible a decision between the oriented growth and oriented nilcleation theories of recrystal-lization textures. The basic experimental program consisted of measuring the rate of growth of a single recrystal-lizing grain consuming a strained single crystal, with the orientations of both grains preselected so that the effect of orientation on growth rate could be determined. A prerequisite for such an experiment is a strained single crystal which will support the growth of a new grain but which will not spontaneously nucleate new grains on heating. That is, the crystal must support the growth of a grain nucleated artificially, but contain no recrystalliza-tion nuclei which will become active at the testing temperature. Beck was apparently the first to note that such a condition could exist," and to make use of the condition for am experiment of the type described here.&apos; The present work was actually suggested, however, by a report of Tiedema". " that an aluminum single crystal strip, oriented with a (111) plane in the plane of the strip and a < 112> direction parallel to the tensile axis, would not recrystallize after 20 pet extension even when heated almost to the melting point, provided that the strip was heavily etched before being heated. This result could not be duplicated in the present work. In fact, it was found that any crystal which deformed in multiple slip (<100>, <112> and <111> orientations) underwent spontaneous nucleation after 15 pet extension, even if etched. However, crystals which deformed in single slip, and which did not develop heavy deformation bands, could be extended 15 pet without showing spontaneous nucleation at temperatures up to 600°C. Crystals oriented within about 10o of <110> which developed heavy deformation bands could be extended 10 pet without showing spontaneous nucleation. In all cases a heavy etch was required to prevent nucleation. Etching was necessary because of the presence of an oxide layer on the crystal surface at the time of straining, which leads to preferential nucleation at the surface.&apos;&apos; Grain Growth Rates Experimental Procedure and Results—Aluminum strips of 99.6 pet purity (principal impurities 0.19 pet Fe and 0.12 pet Si), 1 mm by 1 cm in cross section, were grown into single crystals of controlled orientation by the strain-anneal method of Fuji-wara.&apos;"&apos; " A sharp temperature gradient was maintained in the strips during growth by lowering them into a salt bath controlled at 650°C. Crystal orientations were determined by the etch-pit method of Barrett and Levenson" to an accuracy of ±2O. The crystals were extended by 10 or 15 pet in a simple hand operated tensile machine. Crystal orientations were rechecked after extension, and were found to be in agreement with the orientations predicted by the formula of Schmid and Boas." After extension, the grip ends of the single crystal specimen were cut off with a jeweller&apos;s saw, and the crystal heavily etched (at least 20 pet wt loss) in hot 10 pet Na or KOH solution. A region of severe local deformation was then introduced at one corner of the strip, usually by cutting off the corner with shears. Heating this end of the strip caused a large number of new grains to nucleate at the sheared edge. One of these grains grew to occupy the full width of the strip. The appearance of the strip at

Jan 1, 1957

By Phillip B. Bucky, Fred D. Wright

The present known petroleum reserves are limited, and unless important new fields are discovered the Nation will be dependent, in the not too distant future, upon imports or upon synthetic liquid fuels to supplement domestic petroleum supplies. As a national defense measure, it would appear desirable to develop a substitute source of liquid fuels within the borders of the country if new discoveries of petroleum should Prove disappointing. Congress undoubtedly had this in mind when it passed the Synthetic Liquid Fuels Act (78th Congress, approved April 5, 1944). The act directed the Bureau of Mines to construct and operate demonstration plants for producing synthetic liquid fuels from coal and oil shale, and from forestry and agricultural products. As a part of this program, the Bureau of Mines has built a demonstration plant at Anvil Points, near Rifle, Colo., for retorting the oil shale, and has developed a mine to supply the plant with oil shale. At the beginning of mining operations, the physical qualities of the oil shale, which would have a bearing upon the selection of mining methods and practices for exploiting the deposits, were largely unknown. A comprehensive mining-research program has been set up to determine the best methods and practices to follow to obtain the lowest overall practicable mining cost for producing the oil shale on a large scale. Unusually low mining costs will be necessary for shale oil to be produced commercially. Consideration now is being given to exploiting a series of flat-lying beds 70 ft thick by a room-and-pillar method of three benches with the advance heading at the top. This report is one of a series giving the results obtained in research on mining problems, The structure and physical qualities of the oil shale indicate that the 70-ft interval of the oil-shale measure can be safely mined in open stopes; studies indicate that this method would be the most economical one to use.&apos; As labor will be a major item of expense, the largest equipment that could be operated efficiently in the workings would be required to obtain the lowest practicable mining Cost. It Was therefore desirable to know the maximum safe span of unsupported rooms and the size of pillars necessary to support the overburden. This paper describes the work done at the Columbia School of Mines Barodynamic Laboratory in determining the maximum safe unsupported roof spans and the minimum safe pillar dimensions for the oil-shale mine at Rifle, Colo.

Jan 1, 1949

By E. Horton Jones

INTRODUCTION WE have endeavored in the following "sheets" to give the unit construction costs derived from the building of the Arizona Copper Co.&apos;s new smelter, Clifton, Ariz., starting in February, 1912, and completing February, 1914. 1 In Chapter I-Unit Costs-are to be found the most elementary total unit costs which the accounts provide for. They are usable in the Clifton district. Here too are found the percentages to be added to an estimate for Engineering and General Expense. In Chapter II-Comparative Costs-these elementary costs have been classified, averaged and reported as labor and material unit costs. In such form the labor unit costs, when properly applied to similar conditions as these under which they were derived, are usable anywhere. The material unit costs are better disregarded for more accurate estimates and replaced by a newly priced bill of material. In Chapter III Composite Costs are given. They are unit costs built-up from several elementary units, and likewise units of larger dimensions and simpler application, valuable for

Jan 7, 1914

By J. C. Todd

The volume of air needed to move the combustion wave through each acre-foot of the reservoir is a very important quantity for engineering economic analyses. A new method, which involves backflowing the injection well, has been developed for determining the air requirement .for the forward combustion thermal pilot in the Delaware-Childers field. The method depends on measurement of the total volume of air injected and measurement of the pore volume in the zone swept out by the combustion front. The basic premise of the method is that the pore volume of the swept zone contains air, while the formation around this zone contains flue gas, oil and water. The pore volume of the swept zone is determined by blowing down the pilot section of the formation through the injection well after the pilot is shut down. Oxygen balance is used to differentiate between air from the swept zone and flue gas from the surrounding formation. Data indicate that air&apos;is produced from the swept zone by relatively efficient miscible displacement by the flue gas. The pore volume occupied by the air in the swept zone is determined by simple PVT relationships. The average temperature of the swept zone is calculated by heat balance from the total amount of heat generated during the pilot and losses to the surrounding formation. The new method was applied successfully at the conclusion of the pilot in the Delaware-Childers field; the air required for the reservoir conditions involved was calculated to be 19.2 MMscf/acre-ft of reservoir swept. INTRODUCTION One of the most important pieces of information to be found from a forward combustion pilot is the air requirement; that is, the volume of air needed to move the combustion wave through each acre-foot of the reservoir. Compression costs per barrel of oil recovered, which are a direct function of the air requirement, are a large portion of the expenses incurred in the thermal recovery process. Thus, the profitability of thermal recovery depends largely on the air requirement, which is a measure of the amount of fuel deposited and burned in the thermal recovery process. Several attempts have been made to correlate crude oil properties with fuel deposition and, hence, air requirement.l*2 Other attempts have been made by our laboratory to find the air requirement by material balance, gravity survey, pressure transient analysis,3 magnetic survey and the poten-tiometric model. Better methods are needed to predict more accurately the economics of fieldwide application of the process. Another method of finding the air requirement consists of operating a pilot thermal project for several years. This is followed by an extensive coring program to define the volume swept by the combustion wave. The air requirement is found from the total injected air divided by the volume of the swept region found from the coring operation. This method is costly; an adequate coring program usually costs several hundred thousand dollars. A thermal pilot was operated in a watered-out portion of the Delaware-Childers field, Bartlesville sand, from Nov., 1960, until May 3, 1965. One of the primary purposes of this pilot operation was to determine the air requirement for economic calculations which determine the advisability of expanding the project to the entire 128,000 acre-ft field. Barnes4 has described the result of this pilot operation,, including calculation of the air requirement from limited coring data. The value obtained, as calculated, was 15.8 MMscf/acre-ft. One purpose of this report is to describe a new method of finding the air requirement from a thermal pilot operation. A second purpose is to describe the application of this method to the Delaware-Childers thermal pilot. THEORY AND DESCRIPTION OF THE METHOD The combustion zone in the forward combustion process is propagated from injection w producing

Jan 1, 1970

By Michael J. Messel

THE critical shortage of asbestos fiber in the world today brings to the foreground the question of locating and developing new deposits. The object of this paper is to discuss some of the more important factors which should be considered in the examination and valuation of a new asbestos enterprise. Some of the more important uses of asbestos fiber are for textiles, heat insulators, building materials, filters and a series of other uses. The properties of this mineral, such as fibrous structure, color, strength, silkiness and flexibility, coupled with resistance to fire, certain chemical action and decay make its application unique for certain industrial uses which consume over 500,000 tons annually. These same unique properties which make this mineral so valuable also make a deposit one of the most difficult to appraise accurately, because of the many undeterminable and varying factors which must be considered before a deposit can properly be termed commercial. The majority of the asbestos fiber today, having the above mentioned properties, is sold by grades which are based on fiber length. Present day fiber prices vary over a wide range from $800 to $225 for crude fibers and $300 to $20.00 per ton for milled grades. For valuation purposes a careful study should be made of existing fiber prices and markets. EXAMINATION OF DEPOSITS In carrying out prospecting and examination of a deposit, considerable caution is required to get the necessary information in the form that will have the most value for the final determination. There are two main classes of asbestos fibers, chrysotile and the amphiboles, the chrysotile being, by far, the most important both in abundance and uses. This paper will stress mainly chrysotile deposits, however, the amphiboles have many important uses, especially amosite and crocidalite. Their valuation presents special problems as other factors may be involved, especially as they are not graded according to any well defined and adopted standard but usually according to the use for which they are being supplied. Most chrysotile deposits occur in two main types of rock, (I) mainly in basic igneous, such as dunite and peridotite, (2) to a lesser extent in sedimentary rocks, such as dolomite and limestone. All of these require a certain degree of metamorphism to be favorable to asbestos formation. Approximately 90 pct of the asbestos deposits are derived from serpentinization of dunite or peridotite, whereby the magnesiumsilicate olivine was altered to hydrous magnesium-silicate serpentine. Under certain favorable geological conditions, this serpentine takes a fibrous form having a definite crystal structure, probably due to molecular rearrangement, and is known as chrysotile. The fiber veins are usually ir-

Jan 1, 1947