Search Documents

By W. J. Joslin

The frontal-advance equation can determine how the fluid withdrawal rate and subsurface operating pressure influence oil recovery from pressure-maintained reservoirs having characteristics favorable for efficient vertical segregation. For effective vertical segregation in formations having low dip angles, the requirements are: thick, massive sands, low viscosity oil and high vertical permeability with few discontinuous shale members. This approach has been successfully applied to the LL-370, which is a massive Eocene sandstone reservoir containing crude with an average gravity of 26" APT, a dip of only 3" and vertical permeability of ½ darcy. The average gas cap saturation was calculated for various rates of vertical gas-oil contact movement corresponding to a wide range of reservoir producing rates. This method also evaluated the effect of different pressure maintenance levels on oil recovery. Applicability of this procedure for calculating the present oil saturation in the LL-370 gas cap has been substantiated from field performance, where the oil saturation was computed by comparing oil recovery with the gas cap volume vacated. INTRODUCTION During the natural depletion history of the LL-370 reservoir, located in Lake Maracaibo, Venezuela, excellent vertical segregation resulted in the formation of a thin gas zone over a substantial portion of the oil-productive area. Subsequently, gas injection forced this thin gas-saturated zone slowly downward, reducing the oil saturation in the gas cap to a low value. The oil recovery has been raised considerably above earlier predictions where vertical segregation effects were under-estimated. In order to determine the maximum efficient producing rate and optimum operating pressure for this reservoir, a vertical gas frontal-advance analysis has been made through application of the fractional flow equation. LL-370 RESERVOIR CHARACTERISTICS The reservoir consists of a truncated monocline of massive. highly-permeable Eocene sandstone, called the B-b formation, covering an area of more than 13,500 acres. The original oil in place was 2.17 billion STB. Internal non-sealing faults subdivide the structure into four blocks called the B-6-x.6, 10, 11 and 13, which are effectively bounded by major faulting on the flanks, an unconformity updip to the west, and an immobile aquifer to the southeast. The producing formation occurs at an average depth of 5,250 ft subsea and has a closure of more than 1,500 ft. A typical producing section has a net oil sand thickness of 170 ft. Scattered throughout the section are a few randomly-positioned shale lenses which increase in thickness and areal extent downdip. The reservoir rock and fluid properties vary with depth. The permeability and produced oil gravity are 1600 md and 28" API at the top, compared to 300 md and 18° API at the water-oil contact. The productivity of updip wells is, therefore, much higher than the reservoir average. The reservoir oil was originally saturated at the crest, grading to a slight degree of undersaturation at the water-oil contact. There was no original gas cap; and material balance and the field performance indicate no water influx. Except for the northern B-6-x.6 block, the fluid and rock properties have already been published.' Average LL-370 reservoir properties are shown in Table 1. RESERVOIR PERFORMANCE UNDER NATURAL DEPLETION Fig. 1 shows production performance from 1939 to date. Early development was gradual, with 30 wells pro-

Jan 1, 1965

By D. K. Deardorff, Haruo Kato

D. K. Deardorff and Haruo Kato (U. S. Bureau of Mines)—We wish to refute the 1875" 20°C value that Giessen, et al., report as the transformation temperature of hafnium. Although these authors state that their work along this line will be reported later, we can't leave their value undiscussed, for we believe it to be 125°C too high. Our value of 1750° 20°C, which the authors mention, has been substantiated in our laboratories by the use of three other methods. The first method of substantiation was by heating and cooling curves using a hafnium/tungsten thermocouple, the couple having first been calibrated against a t/Pt-10 pct Rh couple. The second method was by quenching and metallography of dilute Hf-Ta alloys. The third cussion, it may be pointed out that the observations of Rogers referred to large unidirectional strains where the internal cracks or voids appeared only after a strain of 32 pct or more. On the contrary the internal fissures observed, as a result of fatigue cycling, occurred for a total extension of some 5 pct and furthermore followed the directions of the slip zones. Finally, it is not our contention, as implied in Dr. Alden's last paragraph, that the tensile stress is an important factor in crack propagation. Indeed, in connection with the reference to the companion report, special note is made of the fact that "Deformation was apparently concentrated in grains which have a slip plane nearly perpendicular to the specimen axis and thus near the plane of maximum applied shear." This dependence of the growth of fissures on the orientation of the slip planes with respect to the direction of maximum applied shear is clearly shown in work on the torsional cycling of single crystals which has been submitted for publication. method was by heating and cooling curves with W/W-26 pct Re thermocouple. Counting the original resistometric method, four different methods have yielded 1750" 20°C as the transformation temperature of hafnium. All our work on determination of the hafnium transformation temperature has shown that the specimen under test must be quickly heated to and through the transformation temperature if the lowest possible transformation value is to be determined; otherwise a higher value not representative of pure hafnium will result. Speed was emphasized in all methods. In our resistometric work the corresponding voltage, amperage, and temperature readings were taken quickly and the transformation temperature was usually reached within 5 min total heating time. In the thermal analysis work involving Hf/W or W/W-26 pct Re thermocouples the transformation temperature was attained within three minutes total heating time, this time being less because the two variables were

Jan 1, 1963

By W. H. Bassett

Beads of metal frequently appear at the ends of cast-copper wire bars and on the sides of wedge cakes near the top. These are richer in cuprous-oxide than the rest of the casting. A micrographical study of these exudations has been made. It is suggested that the material is forced through the surface while the copper is solidifying. If not eliminated in process of manufacture, it shows on the finished polished sheet copper in patches differing in color from the main body of the sheet. FIGURES 1 to 4 show the copper exudations, at different magnifications, as they appear on the ends of cast wire bars, and on the sides, usually near the top, of wedge cakes. Sometimes the exudations are in fine "drops;" at other times, large masses of the material are found. Microscopic examination of the copper exudation indicates that it is high in oxide and of eutectic proportions. Because of the difficulty of securing a suitable sample, the protuberances have not been analyzed chemically; but the spectroscope shows no indication that there are any more metallic impurities present than in the balance of the copper. The lowest copper plus silver content of the coppers studied for this? paper was 99.914 per cent.; the highest, 99.966 per cent.; so the oxygen content of the whole casting would be well under 0.07 per cent.

Jan 2, 1926

By John W. Trammell, Chester O. Ensign

Efficient mining of copper ore at the White Pine mine in Michigan's Upper Peninsula is partially dependent on the rather unique problem of predicting variations and rock types in a barren stratum called the upper sandstone. The pronounced effect which this formation has on the local mining techniques is reflected by the necessity of deciding whether to mine the sandstone along with ore-bearing rock, thus diluting overall ore grade, or, alternatively, leaving the sandstone behind to form the mine roof. THE OREBODY AND MINING TYPES In the mine, the cupriferous zone of the Nonesuch shale is divided into three major portions (Fig. I). Lying conformably on top of the Copper Harbor formation (or "lower sandstone") is the lower part of the orebody, the parting shale. The parting shale is overlain by the upper sandstone. On top of the upper sandstone, the basal portion (8 ft) of the upper shale is quite similar to the parting shale. Both the upper shale and parting shale are divided into a number of smaller stratigraphic units, each having a characteristic copper content, as shown by the histogram of Fig. 1. Other authors have dealt in detail with the stratigraphy and mineralogy of the orebody, so it will suffice here to call attention to the low copper content of the upper sandstone.

Jan 12, 1964

By AIME AIME

THE following paragraphs, constituting the concluding portion of the Annual Report of the Council for 1903, have been withheld from publication until now, in order to make them as accurate and complete as possible. They will be published in Volume XXXV. of the Transactions in their proper place at the end of the said Annual Report. Franklin Ballou was born in Pittsburg, Pa., May 29, 1845. He was the son of an old resident, Arthur Ballou, a manufacturer and wholesale dealer in vinegar. In early youth Franklin attended the Western University of Pittsburg, but left school at the age of 16 to become book-keeper for his father, upon whose retirement from business, in 1868, he associated himself with Walter C. Childs, of Pittsburg, in the manufac¬ture of furnace-grates and asbestos-cement for blast-furnaces. This firm was known as W. C. Childs & Co., and did a success¬ful business for several years. In 1869 Mr. Ballou married Miss May S. Wilson, daughter of Judge Wilson, of Lewistown, Pa. In 1876 he spent several months traveling in the West and studying the mining industry, which greatly interested him. In consequence of this journey, he wound up his business in Pittsburg and removed in 1877 to Georgetown, Colo., where for several years he conducted a sampling-works, and built up an extensive business as an agent for the sale of ores, besides engaging to some extent in mining enterprises. , It is said that he controlled at one time about one-eighth of the output of the Leadville mines. In the early 80's, he became Vice-President and General Manager of the Bimetallic Smelter at Leadville, of which Mr. David H. Moflat was the principal owner. This was practically the first successful demonstration of pyritic smelting in Colorado. Upon the sale of the works in 1897 to the American Smelting and Refining Co., Mr. Ballou retired

Jan 1, 1905

By A. E. Chute

The shortage of sulfur is not only continuing but appears to be worsening, attended by steadily rising prices. At the same time emphasis on air-pollution abatement is also increasing. These two factors, a rising market and the growth of environmental attention, have encouraged producers to carefully review all possible sulfur sources. As a result, production of sulfur from hydrogen sulfide occurring in petroleum is receiving greater attention than ever before. Until about a decade ago, the practice of recovering sulfur from hydrogen sulfide separated from gases (either found naturally or generated in desulfurization of liquid petroleum) was wide1y recognized but contributed little to total free-world sulfur production. However, during the past ten years, the production of sulfur from this source has increased so rapidly that it now accounts for a substantial portion of total production. This trend shows no signs of slackening, and current forecasts predict that recovered sulfur may become the dominant source of supply within ten years, exceeding mined sulfur production. This paper is intended to list sulfur sources and relationships, and to discuss the potential of producing sulfur from petroleum. The processing involved, in addition to product storage and transportation will also be discussed along with important economic aspects of sulfur recovered from hydrogen sulfide. For many years, most of the world's elemental sulfur has been produced from salt domes, predominantly by the Frasch process. During the past decade, however, another production source has developed so quickly that it is expected to surpass the Frasch production sources within a short time. This new source lies in the petroleum gases and liquids from which dramatically increasing quantities of elemental sulfur are being recovered. In the phraseology of the trade, the sulfur so obtained is know as "recovered sulfur," a term which does not, as one might expect, include sulfur recovered from other sources such as smelter gases. The growth rate of recovered sulfur compared to that of Frasch sulfur, total elemental sulfur, and total Free World sulfur in all forms is shown in Fig. 1 Since 1963, sulfur consumption has exceeded production,with the natural result that the price of sulfurhas continually increased. The posted price reported for f.o.b. Port Sulphur, La., has risen from as low as $18 per ton in 1962 to $32.50 per ton in mid-1967. With freight and other charges, delivered prices have of course run much higher, amounting to $45 or $46 per ton on the east and west coasts. In some cases, spot sales for as much as $60 have been reported. Although it is playing an ever-increasing role in the sulfur market, recovered sulfur was originally a by-product of the removal of hydrogen sulfide from natural and petroleum refinery gases. Today, however, it is often the most valuable product of a multi-product processing facility. Since there are two major sources of recovered sulfur—production and refining processes —natural gas is included with liquid petroleum for purposes of this discussion. Sulfur from these sources is produced in the form of gaseous hydrogen sulfide which is removed from a gas stream and converted to elemental sulfur. Gases in which hydrogen sulfide occurs naturally are natural gas and the gas produced from a high=pres-sure crude=oil or condensate field.

Jan 1, 1969

[Separates of all the Pamphlets published within the last three years (starting with No. 1469) are available, with few exceptions, at Institute headquarters. Separates of all the Technical Publications are also available. All the papers are on file in public, university and technical libraries, and when so indicated in the list, may be found either in the TRANSACTIONS or in the special volumes issued by the Institute.] METAL MINING TRANS. PAMPHLET VOLUME NUMBER TITLE AUTHOR MEETING AND PAGE* -1033 Relation of Air Pressure to Drilling H. W. Seamon New York 66,743, 766 Speeds of Hammer Drills Feb., 1921 1034 Time Factor in Depletion of Mines J. W. Roberts New York - 66,711 Feb., 1921 1 1035 Calculation of Ore Tonnage and Grade J. E. Harding New York 66, 117, 122 from Drill-hole Samples- Feb., 1921 1038 Discussion of Papers Presented in 1920 1041 Run-off and Mine Drainage - H. N. Eavenson New York 66, 624, 630 Feb., 1921 1043 The Health of the Underground Worker A. J. Lanza New York Feb., 1921 1045 Dust-ventilation Studies in Metal D. Harrington New York 66, 272, 282 Mines Feb., 1921 1046 Discussion of Papers Presented at New York Meeting, 1921 1072 Breakage and Heat Treatment of Rock- B. F. Tillson New York 66,758 drill Steel Feb., 1921 1073 Discussion of Papers Presented at New York Meeting, 1921 1076-M Analysis of Some Drill-steel Tests F. B. Foley New York - 66,789 Feb., 1921 1077-M Application of Magnetic Analysis to C_ W. Burrows New York 66,796 Root Drills Feb., 1921 1078-M Heat Treatment of Rock-drill Steel G. H. Gilman New York 66,779 Feb., 1921 1080 What is the Ideal Drill Steel? F. H. Kingdon New York 66,807 Feb., 1921 1081 Rock Drill Steels, etc. W. T. Ober New York 66,814 Feb., 1921 1082-C Underground Mine Development, Its J. B. Dilworth Wilkes-Barre 66, 715, 721 Definition and Valuation Sept., 1921 1084 Drill Steel from Hollow Ingots P. A. E. Armstrong New York 66,809 Feb., 1921 1088 Authors' Replies to Recent Discussion 1092 Heat Treatment of Rock Drill Steel A. E. Perkins New York 66,811 Feb., 1921 1096-M Octagonal Ventilation Shaft of Davis- J. L. Bruce Wilkes-Barre 66, 252, 268 Daly Copper Co. Sept., 1921 1100-C Determination of Electrical Equip- G. Bright Wilkes-Barre 66, 580, 605 ment for a Mine Hoist Sept., 1921

Jan 1, 1926

By Max W. Ball

THE geologist or mining engineer, whose work takes him into the western United States, whether for the Government or private enterprises, is likely to be called upon to classify public lands as to their mineral character, or to review such classification already made, usually by a Government geologist or mineral inspector. The public-land law covering the matter is clear and logical, and a knowledge of its simpler principles is necessary to intelligent classification work. There are two classes of cases in which a classification of lands as mineral or non-mineral may be required: .first, cases in which lands classified as mineral will be retained by the Government and lands classified as non-mineral alienated; second, cases in which lands classified as mineral will be alienated and lands classified as non-mineral retained.

Jan 1, 1921

By C. E. Birchenall, R. H. Condit

THREE surface activity procedures are in com--L mon use for the determination of diffusion coefficients in solids. In the oldest of these' the activity observed at the original surface is compared before and after diffusion, where all the activity is in a thin, plated layer on the surface before diffusion. Partial absorption of the radiations from active atoms which have diffused below the surface reduces the effective activity after diffusion. The formula employed to calculate the diffusion coefficient is where F, is the ratio of final to initial activity at the surface, measured with identical counting geometry; Z=u3Dt, where D is the diffusion coefficient; t is the diffusion time; and u is the absorption coefficient for the radiation in the solid as defined by Lambert's law. This absorption law implies that all the rays are parallel to each other and normal to the specimen surface. This assumption of a collimated beam used by Steigman, Shockley, and Nix has been adopted by all other investigators and, although it gives results which are approximately correct under restricted physical conditions, it does not represent many actual circumstances. It is the purpose of this paper to show the importance of the divergent rays and to indicate a procedure for taking them into account. In the residual activity method the activity is determined on a series of surfaces ground on the specimen at progressively greater depths in the diffusion layer parallel to the initial surface. Gruzin2 has de- rived a formula for this procedure, which may be put in the form where I is the ratio of the activity measured at a newly ground surface at distance k below the initial surface to the activity at the initial surface measured after diffusion, and K= k/2p Dt. A third procedure involves the autoradio-graphic determination of activity on a plane ground at a small angle to the initial interface through the penetration zone. Aut oradiography can be particularly sensitive to the oblique rays. Unlike most counters which detect essentially all ß particles or X-rays which enter the active volume as a single event, the photographic emulsion may be thin enough so that oblique rays with longer path length in the emulsion produce more darkening than rays which move normal to the film plane. Consider a plane containing a source of radiation uniformly spread over a circle and a point counter located on the perpendicular through the center of the circle. As the counter moves along this line, the total angle 6, at the counter subtended by the specimen will vary. For a fixed counter distance, let 6 be angle between the counter axis and the line connecting the counter to a point P on the active plane. If an absorber of thickness X is interposed parallel to the source between counter and source, the ray from point P to the counter will pass through an absorber thickness X secant 6. Exponential absorption is assumed to hold for all rays. If r, is the ratio of intensity at the counter with absorber to the intensity without absorber and a = pX, 1 00 The behavior of this integral, evaluated numerically,

Jan 1, 1957

By Enrique Touceda

For a number of years prior to the world war, the firm of Geo. H. Thacher & Co., of Albany, N. Y., was engaged in the manufacture of marine and other gray-iron castings. At the outbreak of the war the firm decided to specialize in the manufacture of propeller wheels. It attacked the problem, therefore, from a foundry point of view, seeking to produce a casting that would be so accurate that no subsequent machining would be required on the blades, also from the point of view of the ship builder. There were two general methods of manufacture, the shortcomings of which have been freely acknowledged. In the sweep method, the nowel, or bottom half-mold, for each blade is swept up by a spindle beam and pitch race, while the top half-mold for each blade is built up individually. In the pattern method one individual blade, with the hub or hub portion, is mounted on a spindle and the individual blade mold formed, the pattern is then rotated on the spindle to the position for the next blade, etc. In rare cases wheels were made from a solid pattern. Owing to the cost of the pattern, its failure in many instances to be correctly made, and (when made of wood) its early and sure distortion the disadvantage of this pratctice is obvious, while metal patterns in most instances were prohibitive in cost. In these methods both green-sand and loam molding was practiced. The casting produced by either method can be considered only as a blank from which the propeller must be machined. The back surface of each blade must be chipped to the templet and through this procedure chipped to such accuracy as will be required for a static balance. Inasmuch as the work done by the machine tool is confined to the driving face of the blades, not only is perfection most difficult, but corrosion will be greater because of the removal of the dense skin of the casting and the local strains set up by the pneumatic tool in chipping. To produce a finished 9-ft. propeller for a Navy destroyer required from 8 to 21 days of foundry work and about the same length of time for the machining. Through the use of the Thacher process, only as many hours are required, besides it is possible to produce a finished casting in perfect conformity with any particular propeller-wheel design.

Jan 1, 1922

By Enrique Touceda

For a number of years prior to the world war, the firm of Geo. H. Thacher & Co., of Albany, N. Y., was engaged in the manufacture of marine and other gray-iron castings. At the outbreak of the war the firm decided to specialize in the manufacture of propeller wheels. It attacked the problem, therefore, from a foundry point of view, seeking to produce a casting that would be so accurate that no subsequent machining would be required on the blades, also from the point of view of the ship builder. There were two general methods of manufacture, the shortcomings of which have been freely acknowledged. In the sweep method, the nowel, or bottom half-mold, for each blade is swept up by a spindle beam and pitch race, while the top half-mold for each blade is built up individually. In the pattern method one individual blade, with the hub or hub portion, is mounted on a spindle and the individual blade mold formed, the pattern is then rotated on the spindle to the position for the next blade, etc. In rare cases wheels were made from a solid pattern. Owing to the cost of the pattern, its failure in many instances to be correctly made, and (when made of wood) its early and sure distortion the disadvantage of this pratctice is obvious, while metal patterns in most instances were prohibitive in cost. In these methods both green-sand and loam molding was practiced. The casting produced by either method can be considered only as a blank from which the propeller must be machined. The back surface of each blade must be chipped to the templet and through this procedure chipped to such accuracy as will be required for a static balance. Inasmuch as the work done by the machine tool is confined to the driving face of the blades, not only is perfection most difficult, but corrosion will be greater because of the removal of the dense skin of the casting and the local strains set up by the pneumatic tool in chipping. To produce a finished 9-ft. propeller for a Navy destroyer required from 8 to 21 days of foundry work and about the same length of time for the machining. Through the use of the Thacher process, only as many hours are required, besides it is possible to produce a finished casting in perfect conformity with any particular propeller-wheel design.

Jan 1, 1922

By M. H. Yoo

Possible interactions of the perfect dislocations of six slip systems or the c dislocation with the (10i2f (ioii), {ioIi}(ioiZ), {1122}(1123), and {1121}(ii26) type twins in hcp metals have been analyzed from the crystallographic and the energetic points of view. Twenty-six distinct types of possible interactions were identified, and those selected based on crystallographic constraints were examined for their energetic feasibilities by use of the anisotropic energy factors. No long-range elastic interaction exists for a dislocation when its Burgers vector is parallel to the twin interface. Under a suitable applied stress, a screw dislocation can cross slip at the twin interface. For basal mixed dislocations in cadmium and zinc, the interaction with {1012} twins is found to be attractive, indicating that incorporation of these dislocations into the twins is energetically feasible and that twin growth will result. On the other hand, the interaction between both basal and Prism mixed dislocations and the {1012} and (1121) twins is found to be repulsive in Mg, Co, Re, Zr, Ti, Hf, and Be. This indicates that under an applied stress a local stress concentration will develop due to a dislocation pileup at the interface, which may result in a site for either the nucleation of other twins or the formation of a crack, depending on the cleavage strength. WHEN a metal undergoes plastic deformation, a certain configuration of slip dislocations will result in a state of dislocation pileup against an obstacle. The stress concentration thus developed may enhance the process of twin nucleation and also twin growth. Furthermore, once formed and dispersed in the crystal, twins can act as effective barriers against slip dislocations. The degree of such mutual influence or interrelation between slip and twinning is generally known to be pronounced in the case of hcp, metals. It is also known that deformation by twinning occurs more commonly in hexagonal metals than in cubic metals. In fact, under suitable stress states, all hexagonal metals exhibit {1012) <1011> type twinning.&apos; In addition to this common type, deformation by (1151) <1126> type twinning occurs in zirconium, titanium, and rhenium, which show remarkable ductility.&apos; The importance of twinning during general deformation to the ductility of hcp polycrystals has been briefly discussed in recent review works.2&apos;3 The purpose of this paper is to analyze the interaction between slip dislocations and twins in the hcp structure and to discuss the nucleation and growth processes of twinning and the role of twinning in the <"°" noil) o, 1/3[112O] (OOO2) 1/3[1123] Fig. l—-Slip systems in hcp structure. ductility of hexagonal metals. The problem will be discussed from the geometric and the energetic points of view in a manner similar to that of the previous work on zinc.4 Since hcp crystals deform by several slip and twin systems, numerous interactions result as possibilities. The Burgers vectors of six slip systems and the c dislocation shown in Fig. 1 and the four twin systems listed in Table I are considered here. A complete tabulation of the possible interactions is followed by discussion of those that are more likely to occur on the basis of crystallographic constraints and energetic considerations. 1) CRYSTALLOGRAPHY OF TWINNING The crystallographic elements, K1, K2, n1, and n2, for the four compound twin systems are now well established.= A unit cell with the base vectors n1, and n2 is shown in Fig. 2 for each twin system. The unit cell before twinning is shown in solid line, and the corresponding unit cell after twinning is shown in dashed line. Also shown in Fig. 2 are the following crystallographic parameters: S is the plane of shear, d the interspacing of the twin habit planes K1,Ø Iis the acute angle between n1, and n 2, e is a numerical factor, and q is the number of K, lattice planes intersected by 17&apos;. These parameters can be expressed in terms of the axial ratio, y = c/a, as listed in Table 11. The macroscopic shear strain of twinning, s, and the magnitude of a "unit twin dis-l~cation,"4 bt, are also expressed in terms of y and given in Table 11. In Table 11, K1 and q1 are given in both Miller-Bravais and Miller indices. In double lattice structures, shuffling of atoms in addition to a homogeneous shear of the lattice is generally required if the original crystal structure is to be restored after twinning. The extent of current understanding on this problem of atom shuffling is per- Table I. Four Twin Systems in Hcp Structure

Jan 1, 1970

By John Birkinbine

(New Haven &apos;Meeting, February, 1909.) AWAKENED public interest in efforts to conserve natural resources will certainly be appreciated by the members of the American Institute of Mining Engineers, and a discussion upon conservation may well form a part of one of the Institute meetings, for the records of papers and discussions which appear in the 38 volumes of its Transactions are replete with evidence of effort&apos;s in this direction. Every process which reduces the fuel consumed or the power applied per unit of product; every utilization of waste material, or employment of that formerly rejected, to obtain something of value ; every feature of construction or operation which lessens the labor required or increases the output per employee, is an advance in the direction of true conservation. This may not appear from the records of late conferences or from published articles, in which the effort seems to be concentrated upon reducing the consumption and presenting to the people of the country estimates of exhaustion of natural resources. I rejoice in the awakening of public interest in a matter so important for the present and future welfare of our nation; I appreciate the possibility of much good following conferences of the Governors and delegates from various States and from national societies; and I recognize the interdependence, not only of different States, but of contiguous nations. In fact, the marvelous development of transportation by land and by water, and the decreasing rates at which commodities can be moved great distances, have in many cases practically obliterated geographical boundaries, and nearly every country on the globe can either market its product in other lands or draw upon them for raw or manufactured materials ; hence, conservation is an international subject.

Apr 1, 1909

By D. L. McElroy

SAFETY in coal mining received especial attention by the public in general and the mining industry in particular during 1940 and early in 1941, owing primarily to the six explosion disasters which occurred last year with a total of 276 fatalities. This was the largest number of fatalities due to explosions in bituminous coal mines since 1928, when 347 lives were so lost. But facilities due to explosions have had a definite decreasing trend since 1907, in spite of bad years such as 1917, 1924, 1932, 1937, and 1940. Although the upswing in explosion fatalities in 1940 is lamented by all, none will admit it represents a trend and it will serve mainly to stimulate ways and means of further reducing these disasters.

Jan 1, 1941

By Donald A. Dahlstrom

In 1961 it became increasingly more evident that significant technological changes must be made in minerals beneficiation. The status quo in technology in today&apos;s competitive markets will not be tolerated. Higher productivity, greater recoveries and newer and better products must be sought and incorporated with lower operating costs. In other words, "when you build a new mill, don&apos;t build an old mill." Recommended reading for proof of the vital necessity of new methods and techniques is in the September 1961 issue of MINING ENGINEERING. The article by one of MBD&apos;s cherished and true veterans, E. H. Rose, is entitled "Iron Ore: The BIG Picture". Because of new beneficiation methods for iron ores, nearly 47 million tons of plus 60% iron concentrates will be produced and another 40.1 million tons of capacity will be under construction or committed. Thus in a relatively short period, 87 million tons of this high-grade iron concentrate with record low silica will be available. As Mr. Rose also points out, "in gross tons, without allowance for better grade, this is the equivalent of almost exactly two-thirds of all iron ore used for all purposes in the U.S. and Canada in the peak years of 1953 or 1957." Needless to say, improved mineral beneficiation methods have had far more reaching effects than just the production of higher grade iron concentrate.

Jan 2, 1962

By Sherwin F. Kelly

MANY baffling problems of crustal geology-of warping and folding, elevation, subsidence, and great dislocations of the earth&apos;s surface-may now be on the verge of yielding to the science of geophysics. Electric, magnetic, gravitational, geothermal, and seismic methods are being turned to the gathering of geological evidence buried by deep layers of rock, or lying beneath the waters of the oceans. In this hope, B. L. Miller expresses the opinion that these geophysical studies will sup- ply useful data bearing-on some of the more theoretical problems of North American geology. Among these for example, is the explanation of how Appalachia disappeared. This ancient land mass is supposed to have foundered beneath the Atlantic Ocean after the close of the Paleozoic era and the question arises, was it warped or faulted downward? The geophysical data, though meagre, indicate that the surface of the dense, basal rocks, the probable remnant of ancient Appalachia now underlying the Continental Shelf, slopes downwards to a depth of some two miles below sea level at a distance of 140 mi. from shore: thus suggesting that the subsidence was the result of warping downward rather than abrupt faulting.

Jan 1, 1938

By Kenneth Cottingham

The area described herein is situated on what is known as the Arches Fork anticline in Roane and Calhoun Counties, W. Va. When the area was first mapped, it was felt that well records would give a more intimate idea of conditions, both structural and lithologic, than could be expected from surface horizons. The surface formations are chiefly members of the Monongahela series, though northward the hilltop outcrops are those of the Dunkard. Neither series offen a key horizon sufficiently definite to be satisfactory, although the structure as determined from well records was later checked against two of the more persistent surface sandstones. In mapping the subsurface structure, the top of the Big Lime (Green-brier) was employed as the key horizon. The average depth to the top of the Big Lime varies from 1600 to 2000 ft. (487 to 609 m.), while the average thickness as indicated by well records is 113 ft. (34 m.). The oil-producing formation is the Big Injun, lying just below the Big Lime. In two instances, well records show the Lime and Injun separated by a few feet of "break." The Big Injun is recorded as having a variable thickness. Seven logs report it as missing and one gives it the maximum thickness of 105 ft. (32 m.), while the entire average for thickness is 19 ft. (6 m.). Relation of Structure to Thickness of Big Injun The seven wells reporting the Big Injun as absent were located near the anticlinal axis. Moreover, the general tendency is a thickening of the Injun on the flanks of the anticline, increasing with distance from the axis. Manifestly, this apparent anomaly has no stratigraphic basis, as the actual thickness of the Big Injun and the overlying Big Lime was determined by original deposition which no amount of subsequent folding could appreciably alter. Fig. 1 is a skeleton map of structure based on the top of the Big Lime; Fig. 2 is a cross-section showing the thickness of the Big Injun.

Jan 1, 1923

By Kenneth Cottingham

The area described herein is situated on what is known as the Arches Fork anticline in Roane and Calhoun Counties, W. Va. When the area was first mapped, it was felt that well records would give a more intimate idea of conditions, both structural and lithologic, than could be expected from surface horizons. The surface formations are chiefly members of the Monongahela series, though northward the hilltop outcrops are those of the Dunkard. Neither series offen a key horizon sufficiently definite to be satisfactory, although the structure as determined from well records was later checked against two of the more persistent surface sandstones. In mapping the subsurface structure, the top of the Big Lime (Green-brier) was employed as the key horizon. The average depth to the top of the Big Lime varies from 1600 to 2000 ft. (487 to 609 m.), while the average thickness as indicated by well records is 113 ft. (34 m.). The oil-producing formation is the Big Injun, lying just below the Big Lime. In two instances, well records show the Lime and Injun separated by a few feet of "break." The Big Injun is recorded as having a variable thickness. Seven logs report it as missing and one gives it the maximum thickness of 105 ft. (32 m.), while the entire average for thickness is 19 ft. (6 m.). Relation of Structure to Thickness of Big Injun The seven wells reporting the Big Injun as absent were located near the anticlinal axis. Moreover, the general tendency is a thickening of the Injun on the flanks of the anticline, increasing with distance from the axis. Manifestly, this apparent anomaly has no stratigraphic basis, as the actual thickness of the Big Injun and the overlying Big Lime was determined by original deposition which no amount of subsequent folding could appreciably alter. Fig. 1 is a skeleton map of structure based on the top of the Big Lime; Fig. 2 is a cross-section showing the thickness of the Big Injun.

Jan 1, 1923

By Dwight Farnham

Description of Quarry THE shale used at the Renton plant of the Denny-Renton Clay Coal Co., for the manufacture of vitrified paving brick occurs in a hill rising from 200 to 300 ft. above the level of the valley in which the plant is situated. The shale deposit, which is of unknown thickness pitches about 10° to the southeast. The 150-ft. face worked extends approximately east and west, so that the clip, as shown by the photograph, is to the left and into the hill. The shale is overlain with about 50 ft. of gravel, 70 ft. of clay, and 30 ft. of mixed loam and gravel, making altogether from 125 to 150 ft. of overburden. Disposal of Overburden The overburden is removed by sluicing. For this purpose a No. 2 Joshua Hendy giant is used, throwing a 12-in. stream&apos;, and having 60 lb. pressure at the nozzle. The water is drawn through an 8-in. pipe from Cedar river, about 1,000 ft. distant, by means of a Worthington four-stage centrifugal pump, direct connected with a 100-h.p. motor placed just south of the factory, and 1,500 ft. from the nozzle This plant handles the material satisfactorily to a height of about 75 ft. above the level of the top of the shale. When the higher levels are worked, an auxiliary plant consisting of a four-stage Byron Jackson centrifugal pump with a 100-h.p., belt-connected motor, is thrown into the system. This plant is situated on top of the shale and can be discerned at the extreme right of the trestle work in Fig. 1.

Jan 9, 1914

By Douglas Bunting

(Wilkes-Barre Meeting, June, 1911.) WITH the gradual exhaustion of the upper veins in the anthracite coal-fields, the problem of mining at greater depths acquires increasing importance and demands the consideration of a number of important factors, one of which is the greater earth-pressure and the consequent necessity of stronger support o for the roof. Under the pillar-and-chamber system, almost exclusively followed in the Northern anthracite-field, the highest economy in mining is generally secured by leaving, on first mining, pillars only sufficient to support safely the overlying strata. As to the necessary size of such pillars, the opinions of mining experts are widely divergent. In establishing the width of chambers and pillars, the thickness of vein and its depth below the surface have received little consideration. For. instance, it has been quite usual to work both overlying and underlying veins with the same width of chambers and pillars, when the lower vein was two and one-half times as thick, and twice as fits below the surface, as the upper. In view of the generally-accepted theory that the crushing-strength of coal-pillars of the same base-area becomes less with increased height, it is probable, in this instance at least, that the most economical mining has not been secured. This question of adequate pillar-support is economically less important down to about 800 ft. than at greater depths; and it is with reference to mining at these greater depths that the study of the subject here presented has been prompted. The necessity of leaving larger pillars, involving greater mining-costs per ton and also smaller yields per acre, is one of the troubles of deep working. To mine without leaving adequate pillar-supports will result, sooner or later, in a squeeze. Limited areas, it is true, have been mined at certain widths of

Sep 1, 1911