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By P. B. Baxendell

The appraial of producing properties and profitability ntzalysis of a proposed capital expenditure are based on the same principles. In both problems a projection of future cash income is. cornpared to one or more capital expenditures. Several different methods have been in use either to compute a price to obtain a given earning power on the investment or to compute the earning power which will result from a given capital expenditure. One of these, the "Average Annual Rate of Return" method, computes in a simple manner the ratio of the present value of the future earnings after amortization to the present value of the undepreciated balances of the investment over the life of a project. This method, not well known generally, appears to have some rather unique advantages in reducing the computation work required, eliminating trial-and-error solutions, and providing a more accurate answer when applied to oil industry investments subject to the unit-of-production basis of amortization. Its derivation is given and its versatility demonstrated in the solution of certain everyday investment problems. A number of charts, useful in applying this method to profitability analysis and appraisal work, are provided. The current trend in the market values of producing properties is shown. INTRODUCTION Making sound capital expenditure decisions requires an objective means of measuring the productivity of individual investment proposals. Since the best measure of the economic worth of such proposals is their ability to produce profits, it is common practice to grade proposed capital expenditures according to their annual earning power as a percentage of the outstanding capital. The same principles which govern the determination of the rate of return of proposed capital expenditures also apply generally to the problem of determining the appraisal value or purchase price of income-producing oil and gas properties. Both problems are of prime importance in the producing phase of the oil business, where management is faced daily with decisions to drill or not to drill certain development wells, or with the determination of the appraisal value of producing properties. The common feature in both problems is that a projection of future cash income is compared with a known or estimated capital investment to determine itsiearning power or annual rate of return. In the case of development drilling, the cost of the proposed well can usually be estimated with a fair degree of accuracy and the problem consists of finding the rate of return on the invested capital. In the case of appraising producing properties, on the other hand, the desired rate of return is usually known in advance and the problem consists of determining the purchase price which, for the given income projection, results in the fequired rate of return. Certain accounting procedures common to the oil and gas producing business make these two problems and their solutions somewhat different from corresponding problems in other industries, and, in certain ways, simpler. The main difference is in the amortization policy which, for oil and gas production, is frequently on a unit-of-production basis, compared to the amortization on a time basis used in many other industries. The purpose of this paper is to discuss briefly the various methods currently in use for the measurement of productivity of invested capital in producing properties and, in more detail, the derivation and application of what will be called the "Average Annual Rate of Return Method". This rather interesting and not too well known method has some very definite advantages in the solution of many problems common to the oil industry. For the sake of simplicity, federal income tax considerations have been disregarded in the examples used, since they do not affect the principles involved. The use of the production payment route in the sale or purchase of producing properties, which has been amply covered in many other publications, has also not been included in this analysis. METHODS FOK MEASUKING THE EARNING POWER OF INVESTED CAPITAL, Of the many different methods used to measure the earning power of invested capital, four are applicable to oil or gas production ventures. Depending on whether these four methods utilize one or two interest rates, and whether a fixed amortization pattern is used, they may be classified as follows.

By M. K. Seguin

The study described in this paper is first centered on the determination of the physical properties (gravimetric, magnetic, electrical, and electromagnetic) o f metamorphosed iron ores of the Carol Lake-Labrador City District. Different geophysical surveys available in the Carol Lake-Wabush area were interpreted quantitatively and the dimensions, attitude, and tonnage of the ore bodies investigated were determined. A geophysical-statistical study was undertaken which permitted the determination of the grade of iron, magnetite, and, subsequently, specularite in the ore bodies. A discussion of the theory and logical progression of the study and the application of the results to actual geophysical data is presented. The conclusions, which are of real significance from the economic standpoint, may be predicted from the data obtained from geophysical surveys before any diamond drilling is undertaken. An integrated interpretation of this type is useful in planning future exploration work and selecting the most favorable geological structures. It also serves as a guide to minimize and determine tonnage drilling patterns. The general conclusion that a restricted range of residual gravity and magnetic anomalies are a key to exploration is valid. Indeed large depths to the top of deposits are absent since all the ore bodies are overturned synclinal structures with tops located close to the surface. Certain irregular geometries do occur but they are not common and the alignment of the iron ore bodies is sub parallel so that magnetic anomalies are evenly reduced in the earth's magnetic field vector.

Jan 1, 1975

By Waldemar Lindgren

Introduction To the miner, as well as to the geologist, the eastern part of Cuba is a most interesting region. Here we find, in contrast to the moderate relief predominating elsewhere in the island, an imposing mountain range, the Sierra Maestra, extending east and west parallel to the coast, its precipitous front facing the blue Caribbean Sea.. In a geological sense this range is largely an unknown land, the only well-explored region being that in the vicinity of Santiago. The range also contains the most important mineral deposits of the island. They comprise, first, a series of iron deposits yielding a partly hematitized magnetite with low content of phosphorus; second, a remarkable copper-bearing vein at El Cobre; and third, various manganese deposits. Probably more deposits will be found, for the larger and western part of the range is as yet little explored and its slopes are covered by a thick tropical jungle. The following notes are based on a short visit by the senior author in January and February of 1914 to the mines at Daiquiri, El Cobre, and Mayari. For many courtesies and great assistance he is deeply obliged to Charles F. Rand, President of the Spanish-American Iron Co.; to George W. Pfeiffer, General Manager, and to the several members of his staff.

Jan 10, 1915

By H. J. Rose

Sixty-five million net tons of coal were carbonized in the by-product and beehive coke ovens1 of the United States during 1924. This tonnage represented 13.4 per cent. of the bituminous coal which was mined in that year. Table 1 shows production and disposition.2 Table 1.—Production and Disposition of Ocen Coke in 1924 By-product Beehive Total Coal charged into ovens, tons................ 49,061,339 15,914,310 64,975,649 Coke produced (exclusive of screenings and breeze), tons............................. 33,983,568 10,286,037 44,269,605 Average yield of coke, per cent ............. 69.3 6.46 68.9 Disposition of coke, per cent.: Blast furnace.......................... . . 82.6 Foundry............................... . 13.3 6.6 Domestic.............................. . 1.4 6.7 Water gas manufacture and all other uses.. 4.6 . 4.1 Cokes having somewhat different combinations of chemical and physical properties are desired for the various uses listed above, and these properties depend primarily upon the types of coal used. American coals have a wide range of purity and coking quality, and the chief subject of this paper will be the selection of coals for the manufacture of blast furnace, foundry, domestic, and water-gas coke, in by-product coke ovens. It will obviously be necessary to include a discussion of those physical and chemical characteristics that are generally considered essential or desirable for each type of coke. Suitable Coals The examination and development of new sources of coking coal are important because of the irregular and limited distribution of high-grade

Jan 1, 1927

Carlisle: An old friend and good friend, Alan Bateman, is the Silliman Professor of Geology Emeritus at Yale and editor of the Journal of Economic Geology. Now, Alan, let's start off by telling us something about how you became interested in copper. Bateman: Well, after I left Yale in 1913, I was appointed one of the field members of the Secondary Enrichment Investigation. We spent three years in the field studying all the copper deposits of North America, trying to find out how secondary copper enrichment took place. As part of this investigation, I went up to Kennecott, Alaska, in 1916. After the trip I was asked by the president of the company to become consulting geologist to them. I accepted his offer, and to this day I'm still consulting geologist to the Kennecott Copper Corp. Up at Kennecott, there were both Henry Krumb and my good friend Henry DeWitt Smith, who was general superintendent. He and I had been together at Yale, and I had ushered at his wedding. Interestingly enough, Henry took his bride to Alaska and I took mine there two months later. My assistant was Don McLaughlin, and I think that was his first experience in a mining camp. We published a paper on Kennecott together and cemented a friendship lasting to this day.

Jan 11, 1964

By L. A. Updegraff

Before discussing the application of capacitance for the measurement of moisture content in a moving stream of coal it might be well to first give a brief description of the process and then show how it can be applied to the coal industry. A capacitor may be described as a device having two conductors separated by an insulator, the conductors hereafter being designated as a test cell or test plates and the insulator as the dielectric. Capacitance, therefore, is a measure of the ability of a capacitor to store an electrical charge. Two basic factors that affect capacitance are the dimensions of the capacitor and the dielectric constant of the insulator. Capacitor dimensions which affect its capacity are the area A of the conductive surface, and the distance d between plates. Capacitance is inversely proportional to the distance between plates and directly proportional to area A, so if capacitance is indicated as C and the dielectric constant as K the equation for capacitance would be C = AK/d. The dielectric constant can be described as the ratio of the actual capacitance of any given material to that of a vacuum, which is unity. In industrial applications the area of the plates remains constant as also does the distance between them, leaving the dielectric constant as the only variable to affect the capacitance measurement. Figure 1 is a schematic diagram of an r-f excited capacitance bridge in which a test cell is part of the circuit. This bridge consists of four capacitors in two pairs connected across an a-c voltage source. In one side of the circuit the two capacitors are fixed but in the other side they are variable, one being the rebalance capacitor operated by the servo motor and the other the test plates between which the dielectric passes. Capacity of the plates is a function of the dielectric constant of the material between them and is measured at radio frequency. Within the recording instrument is an r-f oscillator and a 60 c ps modulator. The radio frequency signal is generated by the oscillator, modulated by a 60 cps wave, and sent to the bridge. Therefore the signal entering the capacitive bridge is a radio frequency carrier with a 60 cycle envelope, If the bridge is in balance as the signal enters there would be no voltage drop and so no output by the detector. As long as the dielectric constant remains the same the bridge will stay in balance. However, any change in the dielectric constant, which in this case would be a change in moisture content, would affect the bridge. Higher moisture increases the capacity of the test cell which causes less voltage to develop across it causing imbalance of the bridge. This in turn causes a radio frequency signal to appear at the detector. Output from the detector is a 60 cycle ripple which is in proportion to the imbalance of the circuit. A 60 cycle amplifier boosts the detector signal to enough power to drive the servo motor which positions the recording pen and also rotates the variable capacitor, to which it is mechanically connected, to bring the bridge back in balance. An increase in moisture causes the servo motor to rotate in one direction, but a decrease causes imbalance in the opposite direction, and thus rotates the motor in that direction. This brings the bridge back in balance and stops the motor. The bridge shown in Figure 1 has been modified so as to provide a wide range of adjustments. Coarse and fine span adjustments located in the recording instrument are set to govern the amount of pen movement for a given change in capacitance. A measuring head unit contains coarse and fine zero adjustments for

Jan 1, 1961

By C. F. Riisness, E. R. Parker

THAT grain size has a great effect on the mechanical properties of metals has been recognized for a long time. Bassett and Davis1 in 1919 did excellent work in [ ] determining the effect of grain size on the hardness of brass. About the same time Jeffries2 and Sykes3 ascertained the effect of grain size on the strength and ductility of several metals at temperatures ranging from 80°K. to their melting points. When creep was recognized as an important property of metals, those engaged in the study of this property tried to determine the effect of grain size 4-9 on creep rates. Unfortunately, most of the investigations were conducted on only two grain sizes, often designated simply as "fine" and "coarse." It is well known that at high temperatures coarse-grained test bars creep less than fine-grained bars. The relation between grain size and size of test bar, [ ] however, has been frequently overlooked. In his early work, Jeffries2 showed that the number of grains in the cross section has a more important influence on the properties of the material than the actual grain size. More recently Hanson and Sandford10 and Pell-Walpole,11 in their measurements of the creep and tensile properties of tin, tested a wide range of grain sizes and correlated the grain size with the strength. Hanson9 later established the relation between the number of grains in the cross section and the. creep rate: At high temperatures, generally a coarse-grained structure is considered superior in creep to a fine-grained structure, but it is evident that for a given bar size continuously increasing the grain size will

Jan 1, 1944

By M. Cross

INTRODUCTION The results of the Japanese dissective investigations have [l-4] transformed our understanding of how the blast furnace operates. These studies revealed an internal structure of the furnace burden with five main zones, as illustrated in Figure 1. In the granular zone the charged material retains its structure whereas in the cohesive zone the iron ore particles are at advanced stages of reduction and form a semi-molten mass with a relatively high flow resistance. In the active coke zone molten iron and slag flow through a matrix of loosely packed coke. The raceway is a relatively small void space generated by displacement of coke due to the hot blast momentum, whilst the hearth is packed with coke, slag and molten iron. [ ] It is now well appreciated that furnace control is largely achieved and maintained by using the burden charge distribution to determine the gas glow distribution within the furnace and, hence, the shape and extent of the cohesive zone. In fact, Wakayama et a1 [5] of Nippon Steel Corporation state that optimum furnace operation is synonomous with the formation of a desirable cohesive zone shape, which in turn is almost solely determined by the burden charge distribution and its mechanical properties [6]. Much of the development work on operating furnaces since the dissective investigations has been oriented towards the identification of external furnace measures which reliably predict the shape of the cohesive zone. Currently the most popular measures are top gas temperature, velocity and CO/CO, ratio profiles [5]. More recently pressure distributions as evaluated from a series of wall measurements down the height of the furnace are also being utilised [7] to identify the position and shape of the cohesive zone. A great deal of emphasis has been placed upon achieving a consistent quality in the burden charge materials, establishing a suitable set of operating conditions and only making changes when forced to, ie., the operation for some reason moves outside a desired operating range or the production requirements change. Operational control schemes based upon this philosophy (eg., Kawasaki's GO-STOP system [8]) have been remarkably successful at achieving both high production rates and relatively low fuel costs. Mathematical models have long been used as tools to assist in the analysis of the blast furnace process. Although, the models have been useful in post-operative analysis and for identifying trends, etc., they have not proved reliable for detailed design criteria or as the basis for effective control schemes. Such mathematical models have moved from simple statistical correlation, through overall and stagewise heat-and-mass balance calcu-

Jan 1, 1984

By M. ROWE, H. E. Gilliland, L. BARNES

The authors of this paper are to be commended for a clear exposition of a timely subject. However, some important conclusions, in addition to those presented in the paper, can be drawn from the results of their elaborate and rather complete numerical computations. First of all, the major part of the calculations presented in the paper are for semi-infinite slabs of oil shale (the authors designate this as Model I) and a question must be posed — Are these elaborate computations needed to arrive at realistic estimates of the shale oil displaced. Consider the model of Lauwerier* that corresponds to the authors Model I if thermal conduction parallel to the fracture be neglected. If one also neglects the finite (but relatively small) heat capacity of the material in the fracture, it is easily shown from Lauwerier's solution that the cumulative oil production would be:

Jan 1, 1969

By Grafton Thrasher

For the proper discussion of this subject it is necessary to incorporate in this paper the substance of part of an article published by rite in Metallurgical and Chemical Engineering for January, 1915. CAST-IRON TEST PLUG, SHOWING LOW MOTTLED AND MOTTLED FRACTURES. Several years ago, while I was thief chemist for a malleable-iron company, it occurred to me that the mere regulation of silicon was not sufficient to produce the desired degree of chill. But only after repeatedly encountering this fact in befit open-hearth and air-furnace, as well as cupola metal, was I led to regard variation in the total carbon as the principal cause of disturbance; and I resolved to determine the total carbon as well as the sill on ill every heat, and by a carefully prepared test piece to gauge the approximate degree of chill. The test piece selected was a round plug, 2 in. in diameter and 12 in. long, cast on end

Jan 10, 1915

With only one certain exception coal was never used by the Indians, before white men came to America, for any purpose except as an ornament or for paint. Within the past few years it has been discovered that the Hopi Indians in Navajo County, Arizona, used lignite for burning pottery, about 1000 A. D., as dated by tree rings. They were able to obtain a clear color in their ware that could not be obtained with brushwood fires. The coal was mined by hammers from outcrop openings, some of which can still be seen, and the tools used have been found in them.1 (See also p. 376.) Small figurines made of splint or cannel coal have been found at various localities in western New York, in Ohio and possibly other places, evidently made for ornaments. There is no reason to think they are of any greater age, if as old, as that mentioned above. Some crushed coal was used by the Indians as a black pigment in painting themselves, but apparently the eastern Indians never used coal for any other purposes. Some think that several tribes of Indians in the Northwest, along the Missouri, used coal as fuel, the basis being a statement attributed to Radisson about 1660. In the Jesuit Relations of 1659-1660 it was stated that Radisson anti Groseilliers had just returned from a visit to Lake Superior and beyond. "In the country of the Poualak, which means 'warriors' they say `as wood is scanty in supply and small in size in their country, nature has taught them to make fire with coal from the earth (charbon de terre) and to cover their cabins with skins.'"2 This statement was only hearsay with the good fathers, and the reputation for veracity of the two explorers is not of the best, and it is extremely probable that instead of coal they used turf, dry grass or buffalo chips. In fact in Radisson's Voyages' he does not mention coal at all in his account of the third voyage, when he was supposed to have seen it used. His accounts of his travels are badly mixed, and he and his companions were much better travellers than narrators. None of the early travellers up the Missouri River saw any evidence even then that the Indians were familiar with the use of coal. In the writer's opinion it is unlikely that coal was used as stated by the Jesuits.

Jan 1, 1942

By Richard M. Foose

MOST of the roofing granules produced in Pennsylvania are made by two companies at three plants. The Advance Industrial Supply Co. has three quarries and a mill at Gladhill Station, in southern Adams County. The Funkhouser Company is actively engaged in mining, quarrying and milling at Charmian, about one mile west of Gladhill Station, and at Delta, in southern York County. These three plants produced approximately 100,000 short tons of granules in 1943. The production of roofing granules in 1937 for the whole country was only about 500,000 tons, generally indicating the large growth of the industry since that time. The fundamentals of producing roofing granules were discussed comprehensively by G. W. Josephson in a paper before the Industrial Minerals Division in October 1943 (Mining Technology, March 1944). The purpose of this paper is to describe the actual methods of mining the rock and milling it to make roofing granules, as practiced by the three Pennsylvania plants. MINING AND MILLING Funkhouser Company (Delta) The Funkhouser Company, near Delta, in southern York County, Pennsylvania, operates three joined quarries and a mine in the Peach Bottom slate. The joined quarries extend 1200 ft. in a northeast southwest direction along the strike of the slate cleavage and are about 200 ft. wide. The working face is about 45 ft. high. The quarrying operation is rather simple: Ingersoll-Rand Jackhamers, 1-in. and 1 1/4-in., with hollow drill steel, are used to undercut the quarry face with10-ft. holes. The face is "blown" and allowed to slump on the quarry floor. Loaded by a Marion electric shovel into trucks, the shattered rock is taken to the primary crusher 2500 ft. away. In addition to the normal quarrying operations, a drift into the northeast wall of the middle quarry was begun about 1935 and has advanced about 2000 ft. since then. Rooms have been driven at angles to the drift along choice beds of slate. The drifts and rooms have a roof more than 35 ft. high and the main drift and rooms are all more than 40 ft. wide. There is no cribbing at any place in the mine. Several of the rooms were driven upward on a 5º slope and in some of them there was stoping. Ingersoll-Rand Jackhamers are used, and only wet drilling is practiced. When visited in January 1940, an electric shovel was operating at the head of the drift, scooping up the slate blasted out of the working face. This, too, is trucked to the primary crusher. Some of the better quality slate is saved for making slate shingles. The primary crusher, which is a No. 30 McCulley gyratory, receives the slate from the trucks and crushes it to about 2-in. size (Fig. I). This product travels by a 30-in. belt conveyor to Niagara vibrating screens with 2-in. holes. The minus 2-in. product moves to a storage silo by bucket

Jan 1, 1945

By G. R. Mansfield

THE geologic structure of the Idaho phosphate field has an important bearing on the classifica-tion and the exploitation of the lands that contain phosphate. Maps and structure sections1 recently made available show that the phosphate is mainly preserved in downfolded or downfaulted areas. Since the phos- phate beds are generally rather soft and lie between harder and thicker formations they have been forced to adjust themselves to these formations during epochs of disturbance of the earth's crust, so that they are frequently affected by minor folds and by faults which may help exploitation by producing undue thickness at certain places or may hinder it by cutting out the phosphate at other places where according to expecta-tion it should be present. A particularly important structural feature which affects both the distribution and the exploitation of the phosphate beds is the great Bannock overthrust by which one or more slices or blocks of the earth's crust have been pushed over other blocks like ice cakes on a pond. Thus in this region a great flap of folded rocks lies across other rock structures for a distance of approximately 35 miles. Most of the commercially accessible phosphate deposits, shown in the maps that accompany the report cited, are in this flap, which con-stitutes the upper block of the overthrust. In some places, however, the phosphate in the lower block is also accessible. In both blocks post-phosphate rocks exposed at the surface here and there indicate that phos-phate beds may lie at greater or less depth below. The presence of the Bannock overthrust beneath much of the area reported is known by the occurrence of windows in the upper block both within the quadrangles mapped and in areas farther west. The portions of the lower block exposed in these windows show stratigraphic dis-cordance with the surrounding formations. The depth of the fault plane at most places, however, can be told only by drilling or actual mining. Some of the folds in the upper block are relatively deep and it seems fairly certain that the phosphate that may originally have been present in their deeper parts has been removed by thrust faulting. The estimates of phosphate reserves in folds liable to be affected by the Bannock overthrust may therefore need ultimate revision depending on the depth of this fault plane, as it may subsequently be ascertained.

Jan 1, 1928

By R. G. Davies, R. H. Richman

Several techniques, X-ray diffraction, transmission electron microscopy, conventional, metallography, and mechanical property measurements are combined to investigate decomposition in the suPersaturated solid solution Fe-27 at. pct Be. The following sequence of structures for aging temperatures below 400°C is established: massive short-range order, pseudo-FeBe (L2o) order, Fe3Be (DU3) order, sinusoidal modulation of composition, general or continuous precipitation, and discontinuous or cellular precipitation. In addition to this sequence itself, several features of the individual stages are noteworthy; for example, when coherent modulations occur, their development is parallel to (100) everywhere in the specimen apparently without incubation, and both the wavelength and the composition amplitude of the modulations increase with aging time. Two types of discontinuous reaction are observed, depending upon the aging temperature. At low temperatures (<550°C) the boundary-nucleated variety of discontinuous precipitate predominates; but at higher temperatures (>600°C) the crystallographic variety occurs instead. Hardness and flow-stress measurements clearly reflect the quoted structure sequence. Some qualitative aspects of the structure changes and of the relationship between mechanical properties and structure are discussed. BERYLLIUM in solid solution markedly strengthens iron.&apos;" A recent study demonstrated that not only were supersaturated single crystals of Fe-27 at. pct Be very strong, but they deformed primarily by mechanical twinning.3 Such behavior, coupled with the decrease in solid solubility of beryllium in a Fe from about 33 at. pct at 1165°C to about 10 at. pct at 500°C4 as shown in Fig. 1, leads naturally to questions about property changes with aging in this system. In 1929 roll,1 and later Seljesater and Rogers,5 reported that useful increases in strength could be obtained by aging quenched Fe-Be alloys, but it was not until quite recently that any of the details of precipitation in these alloys were studied. Richman6 observed that both an Fe3Be superlattice (with a DO3 crystal structure the same as Fe3A1, illustrated in Fig. 2) and a modulated structure preceded the appearance of a discrete second phase in the 20 at. pct Be composition. Here, a modulated structure refers to a periodic composition fluctuation within one crystal, while its lattice remains coherent. Subsequent work on a Fe-Be alloys by Heubner7 and von Heimendahl and Heubner8 confirmed the existence of the modulated structure, although only an FeBe (L20) ordered structure was detected (also shown in Fig. 2). Both Rich-man and Heubner corroborated the large increases in hardness during aging reported earlier, but other mechanical properties were not examined. Since modulated systems are encountered relatively infrequently, the influence of coherent modulation upon mechanical properties is not well-known. With the accumulation of information about age-hardening systems, it has become clear that many precipitation reactions cannot always be described by the concept of heterogeneous nucleation at some lattice discontinuity followed by diffusional growth. Rather, complex sequences involving prior "preparation" of the matrix are quite common; that is, a transition structure occurs in the parent phase, instead of in some "nucleus" form. Delineation of such subtle sequences appears to be a worthwhile step toward the understanding of solid-state precipitation. Since not many structural progressions of comparable nature have been reported, the objectives of the present survey are to identify and elucidate the various

Jan 1, 1967

THE transformation, in a sample of levitation melted iodide titanium, has been studied with a Leitz hot-stage microscope. The specimen was etched in HF:HNO3: glycerine, (1:1:2) giving a structure shown in Fig. 1, and was then heated at approximately 5OC per min. At 870°C (±5OC) the etching product disappeared, the a-grain boundaries showed in relief, and some new grain boundaries (presumably of ß) appeared (Fig. 2, see arrow). Some evidence of ß-grain growth is indicated by the apparent longitudinal movement of a ß-grain boundary shown in Figs. 2 and 3 (see arrows). The specimen was later heated to 1000°C and then cooled at 2°C per min. At 845°C rumpling of the surface was first noticed, Fig. 4, and continued at constant temperature. The photomicrograph reproduced in Fig. 5 was taken 6 sec after Fig. 4, at 845°C. Fig. 6 shows the structure after cooling to room temperature. The room-temperature structure, showing a rumpled surface has been observed by previous investigators.&apos; These structures presumably indicate a sheer transformation ß - a, athermally nucleated, but capable of isothermal progression.

Jan 1, 1960

By Warren E. Wilson

THE transportation of solids in pipe lines is a matter of deep concern in many fields of engineering. Much experimental and theoretical work has been done in an effort to devise means of designing pipe lines that will satisfactorily transport given solid loads, but there remain many unanswered questions in this field. The present discussion will be confined to a rather narrow portion of this field and will endeavor to point out certain factors that may well be considered when comparing the relative economy of various installations. The data have been presented previously but a new interpretation was prompted by a suggestion in a paper by Professor O&apos;Brien,1 of the University of California, that the friction work per pound of dry material should be considered in determining the relative efficiency of various installations. This method of considering relative economy in various pipe lines leads to some rather unexpected conclusions, especially with reference to the economy of large pipe sizes. A previous suggestion by the writer3 concerning the economy of a rather peculiar type of installation is strengthened. It is not believed that the considerations set forth herein apply directly in the case of dredge lines, where economy is largely a matter of a high rate of pumping in order to reduce the unit overhead charge. However, it is believed that some value may be gained from these considerations in cases involving the disposal of a fixed amount of solids per unit time with a minimum expenditure of energy and at a low cost for replacement of worn pipes. Such situations are not uncommon in the disposal of mill tailings and the disposal of solids deposited from irrigation waters. It was found that data leading to general conclusions for various pipe sizes were not available but certain definite trends are indicated and methods of analyzing available data are presented in the hope that they may be of assistance in preparing engineering estimates on designs of pipe lines of the type described above. ENERGY. REQUIREMENTS Carrying out the idea contained in Professor O&apos;Brien&apos;s paper concerning the method of computing energy required to transport solids, the following analysis leads to some rather interesting conclusions. Let us represent: [Solids load in terms of mass per unit time by W Ratio of mass of suspended solids to total mass of mixture flowing by p Volume rate of flow of mixture by Q Length of pipe by L Slope of energy grade line by s Mass per unit volume of solids by m, Mass per unit volume of liquid by ml Mass per unit volume of mixture by m,,, We then have as an expression for the solids load: W = pQm¬] The work done per unit mass, P, on the mixture to move it along the pipe the

Jan 1, 1945

By George Rice

INSTANTANEOUS outbursts of gas in underground workings are similar in effect to great blasts of explosives, but without heat effects. Fortunately they occur only in a few localities in exceptional coal fields of the world and under exceptional geologic conditions. Such violent outbursts should not be compared with the ordinary outflows of gas into coal mines or with explosions of gas and dust. The phenomenon is essentially one of gas held in circumscribed areas under very high pressure and as a mining face or heading approaches such a place and the mining excavation sufficiently weakens the natural surrounding dam or shell, this is burst by the pressure just as by the discharge of a mass of explosives. The outbursts, so far as known to the writer, have been confined to coal beds and have not occurred in other mineral deposits. Hence, as discussed later, he believes that it is the relation of the gases to the coal material that is a factor in conjunction with others in producing conditions which permit the phenomena to occur when mining is done. The gases in most instantaneous outbursts have been hydrocarbon gases but in two coal fields they have been definitely found to be chiefly or wholly carbon dioxide. One of these localities in which CO2 outbursts have been frequent and have caused loss of life is in the southern part of the Gard basin, near Alais, in southern France. In 1919, the writer visited the Fontaine mine in this field the day following the occurrence of an outburst by which two men were smothered by carbon dioxide and fine dust. After 24 hr. the CO2 had not been entirely removed by the ventilating current. Occasional outbursts of CO2 have also occurred in other small basins in France, causing accidents, as in Puy-de-Dome. However, mines in the Gard basin, north of those in which CO2 outbursts have occurred, have experienced hydrocarbon gas outbursts.

Jan 1, 1931

By Fred A. Hale

Owing to the large area included in the Yellow Pine mining district, and the varied nature of its mineral deposits, a detailed geological description of the district could be covered only in an extensive monograph. This paper is intended as a description of the most prominent geologic features only with special reference to those of economic importance. The first mention of the district was in 1903 by J. E. Spurr, who briefly describes the structural geology of the Spring Mountain range. In 1906, H. F. Bain2 briefly described the Potosi mine. James J. Hillla of the United States Geological Survey, visited the district for a brief period in 1912, the result of which is an excellent reconnaissance report, covering the district in some detail but necessarily with brevity. Since that time, articles covering special features of the district have appeared in the technical press, including some by the writer, and a notable description of the Boss mine, by Adolph Knopf,4 appeared in 1915. Development of the district during the past few years has progressed so rapidly and with so many notable discoveries, particularly with reference to the rare metals, that a further description at this time may prove of interest. The writer&apos;s acquaintance with the district is based on 7 years&apos; continuous residence in the vicinity, beginning with the spring of 1910. A. Location and Topography The Yellow Pine mining district is situated in the southwestern portion of Clark County, Nevada, about 300 miles northeast of Los Angeles, along the line of the Los Angeles & Salt Lake Railroad. The district extends from Mt. Olcott on the north to the California line on the south,

Jan 1, 1918

Preheating Feature of Leyner Oil Furnace for Heating Drill Steel The No. 3 Leyner oil-burning furnace, used for heating drill steel, is now made with a preheating chamber. By this addition it is claimed that the heating capacity and, effeciency of the furnace are increased about 50 per cent. This preheater is a section which fits between the body and cover of the furnace of the old design. It may be attached to an old furnace by simply changing a few bolts. Referring to the illustration, it will be seen that the lower chamber is used for the final heating and the upper one for preheating. The type of burner now furnished with this furnace is suitable for either high- or low-pressure air. It hats merely to be throttled for high pressures and when this is done, it, is as efficient as burners designed especially for high pressures and eliminates the noise common to such burners. This furnace burns petroleum or any of its oils, such a, gasoline, kerosene, distillate, etc. Oil heating has many advantages. The steel cannot be injured by absorbing injurious elements such as sulphur, phosphorus or other impurities which :ire present in nearly all coals, nor from unequal heating since the flame imparts a uniform temperature; further, o lie steel is in full view of the operator at all times.

Jan 3, 1916

By R. W. Nash, A. E. Schwaneke, V. R. Miller

The Bureau of Mines developed a detector for controlling sorting devices to separate the copper-bearing fragments from the barren portion of Michigan native copper and western prophyry copper ores. A successful sorter could be used to preconcentrate the ore and eliminate costly hoisting or hauling of waste. An induction balance unit was developed and used in sorting tests on crushed sized - 2.5 + 1.3-cm (- 1 + 112- in.) ores from the Kingston (0.9% Cu) and Centennial (1.6% Cu) mines of Upper Michigan. Concentrates of 4.0% and 7.5% Cu, respectively, were obtained at recoveries of 85 and 80% of the copper in the feed. Eighty percent of the sorted ore was rejected as tailing. Sorting larger fragments improved the separation efficiency. Tests on - 10+ 5-cm (- 4 +2-in.) sized Kingston (1.6% Cu) and Centennial (2.1 % Cu) ore samples yielded concentrates of 4.3 and 4.5% Cu, respectively, with corresponding recoveries of 92 and 91 %. A bout 60% of the sorted ore was discarded as tailing. Porphyry copper sulfide ores also responded to electronic sorting but at a lower separation efficiency. Sorting response was affected by the degree of segregation.

Jan 1, 1979