Search Documents

By Horace V. Winchell

The laws here referred to are those which define the status of the prospector for mineral deposits in the soil or beneath it, establish his methods of procedure, protect him in his possession while searching for the subterranean treasures, and give him assurance of title when all required conditions have been fulfilled and valuable minerals discovered. Regulations for the operation of mines and the safety and health of mine employees are likewise subjects of Federal and State legislation, but are not within the scope of the present program. Various features of our present laws will be discussed in detail by able students of the subject, and specific remedies will be proposed for the most glaring defects. It is my purpose to present in this paper a summary review of the reasons why revision is needed and demanded by the great majority of those in daily contact with the industry. Reason Number One The first objection to the continuance of the present law is that it was not planned by its framers and the Congress which passed it to apply to many of the kinds of mineral deposits, nor to the mining conditions, which are controlled by it to-day. In 1866, under the title, "An Act granting the right of way to ditch and canal owners over the public lands, and for other purposes," was surreptitiously smuggled into existence our first mining law (14 Stats. at Large, Chap. 262, p. 251). This law provided that "whenever any person or association of persons claim a vein or lode of quartz or other rock in place, bearing gold, silver, cinnabar or copper, having previously occupied and improved the same according to the local customs or rules of miners in the district where the same is situated," etc., a patent might be granted an certain conditions. This was evidently an Act intended to validate claims already initiated, and to accord Federal recognition to mining locations made in

Jan 1, 1915

By J. Charles Miller

NATURAL carbon dioxide has recently been exploited in the United States in consequence of oil and gas developments in the Western States and the growing demand by transcontinental and transoceanic shippers for solid carbon dioxide. The discovery by drilling of commercial deposits resulted in consideration of its geographic and geologic distribution and occurrence. Its wide distribution in nature is evidenced by its occurrence in the atmosphere, hydrosphere and lithosphere. The question of origin of carbon dioxide involves consideration of theories similar to those concerning natural hydrocarbons, although available evidence favors an inorganic rather than an organic source. Areas favorable to development of commercial production appear to be those in proximity to igneous rocks or in the vicinity of decadent volcanic activity, where, it has long been known, the gas is evolved either free or dissolved in the waters of fumaroles, geysers or mud pots. Structure contour maps are presented showing the Wagon Mound anticline in New Mexico and the Farnham anticline, Utah. A well drilled on the latter supplies gas to a 20-ton plant manufacturing solid carbon dioxide at Wellington, Utah, on the Denver and Rio Grande R.R., whence it is shipped to surrounding territory and to the West Coast. Before funds are invested in a plant for the manufacture of liquid or solid carbon dioxide, whether supplied by wells or springs, an effort to ascertain the volume of gas available is advisable. The use of present methods of estimation of gas reserves with modifications to account for the quantity absorbed by any water present in the producing formation is recommended, The Farnham anticline is used as an example and cornputationa are made of the probable volume of gas originally present in the structure. No attempt was made to compute reserves in the Niland area, California, for the reason that in such areas it is believed the volume is indeterminate. INTRODUCTION Carbon dioxide, in liquid and solid form, has found a wide variety of uses other than its primary application in carbonating beverages. It is now used in more than 40 different ways, ranging from cooling or freezing to use in gas or liquid form for mechanical purposes, chemical industry, explosive, fire extinction, and tire manufacturing. Undoubtedly the chief supply of carbon dioxide is obtained from industrial plants or artificial sources and until recently natural deposits of the gas have received little consideration. Few will question the utility and perhaps dependability of artificial sources, which possess the advantage over

Jan 1, 1937

By Joseph S. Malesky

The discovery and development of explosives mark one of the most important findings in the history of civilization. Without explosives our vast economic enterprise concerning the mining of coal, copper, iron, aluminum, and various other ores could not function. Explosives are used in all kinds of construction works, in the razing of old buildings, blasting of trenches, driving of tunnels, and in many other instances common to our everyday life. For these reasons explosives are rightfully referred to as the forerunner of progress. An explosive may be defined as a substance (usually a mixture) that, when flame or shock is applied, yields readily to rapid combustion or oxidation, accompanied by the formation of such relatively large quantities of gases as to produce much violence and pressure which, in turn, react against their surroundings and cause what is termed an explosion. By their very nature the action of explosives is destructive and disruptive of adjacent materials. Decomposition of explosives can occur through deflagration, which is rapid burning or combustion, as in the case of black powder, or through detonation, which is an almost instantaneous disruption, as in the case of dynamites and blasting agents. HISTORY OF BLASTING WITH EXPLOSIVES At one time workmen obtained stone blocks for building by grooving the rock with crude picks, driving wooden wedges into niches in the rock, and pouring water on the wedges; the swelling of the wood forced out the blocks. As late as the 17th century, fires were placed against the face of rock to crack it, and water was sometimes dashed on the heated rock to shatter it by sudden cooling. The progress of our country is synonymous with advancement of the improved manufacture and extended use of explosives. Coal had been

Jan 1, 1981

By Robert Archer

THE proper material of construction for a given purpose is that material which meets the requirements satisfactorily at the lowest ultimate cost. It is consistent with this principle that most aluminum castings are made of an alloy containing about 8 per cent. copper. This alloy possesses mechanical properties satisfactory for general engineering purposes together with manufacturing characteristics leading to the production of finished castings at low cost. It is to the aluminum industry what gray iron is to the iron and steel industry. Just as some services require "semi-steel," malleable castings or steel castings instead of gray iron, there is a certain and growing demand for aluminum castings of superior strength or ductility, or both. Since the beginning of the industry producers and others have sought to develop alloys or processes by which such castings could be made. Out of these efforts have emerged many alloy compositions and special processes, of which only a few have had sufficient merit to survive. It is the purpose of this paper to describe those which seem to the authors to offer the greatest promise for the production on a commercial scale of aluminum castings of superior mechanical properties, with special reference to heat-treated castings. The suitability of an alloy or process for actual manufacture is affected by so many factors that the problem of appraisal is not a simple one. Since this is such an important part of the whole subject it is proposed to discuss briefly some of the requirements. The final verdict is of course the result of commercial trial and experience. It will therefore, perhaps, be profitable to employ a somewhat historical method of treatment in discussing the subject of alloy development.

Jan 9, 1926

By W. R. Hicks, J. E. Pollock, E. Camp

In the oil-refining industry, steel comprises by far the greatest proportion of the materials used in construction work, but with an enormous number of alloy steels and nonferrous alloys available, and a greater knowledge of their properties and corrosion resistance, a substitution first in the "hot spots" and then in locations of moderately severe corrosive conditions will be made as the greater expense can be justified. In new construction work, advantage is taken of the experience already gained and appropriate materials used, whether for high temperatures and pressures demanding additional strength or for corrosive conditions. The locations, however, where equipment in operation constantly requires replacement will soon become evident, as will the necessity for replacement in more resistant materials, if considerable down-time is to be avoided. In what direction and how far to go in the matter of alloys then becomes a question of the highest importance. Obviously, any replacement with more costly material must be justified economically by the promise of longer life, thereby saving both material and installation costs besides the reduction of loss of production. Where the equipment is overcapacity and a regular schedule of cleaning periods is in force, the last item frequently must be ruled out and justification made on the basis of the first two only. Installation of material that will outlast the remainder of the equipment and have no recovery value must also be avoided; this is particularly important in temporary construction or in old equipment that will soon become obsolete. Test Methods Either one of two methods or a combination of both, in the absence of reliable data in similar services, may be adopted to determine to what extent replacement with other, and perhaps more expensive, materials is justified. A unit may be constructed incorporating different metals or alloys so that comparative service may be obtained under the same service conditions; this has been applied in many instances, such as condenser and tank construction, but the opportunities for inspection may be few and

Jan 1, 1935

By J. E. Pollock, W. R. Hicks, E. Camp

In the oil-refining industry, steel comprises by far the greatest proportion of the materials used in construction work, but with an enormous number of alloy steels and nonferrous alloys available, and a greater knowledge of their properties and corrosion resistance, a substitution first in the "hot spots" and then in locations of moderately severe corrosive conditions will be made as the greater expense can be justified. In new construction work, advantage is taken of the experience already gained and appropriate materials used, whether for high temperatures and pressures demanding additional strength or for corrosive conditions. The locations, however, where equipment in operation constantly requires replacement will soon become evident, as will the necessity for replacement in more resistant materials, if considerable down-time is to be avoided. In what direction and how far to go in the matter of alloys then becomes a question of the highest importance. Obviously, any replacement with more costly material must be justified economically by the promise of longer life, thereby saving both material and installation costs besides the reduction of loss of production. Where the equipment is overcapacity and a regular schedule of cleaning periods is in force, the last item frequently must be ruled out and justification made on the basis of the first two only. Installation of material that will outlast the remainder of the equipment and have no recovery value must also be avoided; this is particularly important in temporary construction or in old equipment that will soon become obsolete. Test Methods Either one of two methods or a combination of both, in the absence of reliable data in similar services, may be adopted to determine to what extent replacement with other, and perhaps more expensive, materials is justified. A unit may be constructed incorporating different metals or alloys so that comparative service may be obtained under the same service conditions; this has been applied in many instances, such as condenser and tank construction, but the opportunities for inspection may be few and

Jan 1, 1935

By A. S. Richardson

THe conditions that make necessary the mechanical ventilation of the Butte mines of the Anaconda Copper Mining Go. are due to a number of causes, all of which are incidental to the depth at which mining operations are now carried on, The main object to be accomplished, of course, is the reduction of the temperature and humidity of the air in the working places. Ventilation fans, both surface and underground, have been used for many years, but increasing depth has made the problem much more difficult. Further improvement in both ventilation equipment and methods, therefore, became necessary; and it is the purpose of this paper to describe the work planned and done under the improvement program. The mines of the district have been frequently described in various technical publications, so a description is unnecessary here. From a mine-ventilation viewpoint, compared with coal-mine ventilation systems, the problem is complicated by the fact that the workings to be ventilated are situated on a large number of steeply dipping veins which frequently intersect and are faulted, and also by the fact that the extent, or existence, of orebodies is not definitely known in advance of actual development work. For these reasons ventilation work cannot be planned in advance of actual operations, nor can such regular systems of ventilation as are used in working the more uniform and continuous bodies of coal be developed. When operations are conducted at a normal rate, about 10,000 miners are employed on two shifts, so that about 5000 men will be underground at one time. But as ventilation is necessary to reduce high temperature and humidity due, mainly, to natural causes, the quantity of air per man per minute is not a governing consideration in determining ventilation requirements. Most important among the numerous sources of heat and humidity in the mines are: heat generated during decay of mine timber; heat and humidity given off by mine rock and water; heat generated by oxidation of sulfide minerals; heat given off by electrical equipment; heat generated by mine fires (in certain localities).

Jan 1, 1923

By A. S. Richardson

THe conditions that make necessary the mechanical ventilation of the Butte mines of the Anaconda Copper Mining Go. are due to a number of causes, all of which are incidental to the depth at which mining operations are now carried on, The main object to be accomplished, of course, is the reduction of the temperature and humidity of the air in the working places. Ventilation fans, both surface and underground, have been used for many years, but increasing depth has made the problem much more difficult. Further improvement in both ventilation equipment and methods, therefore, became necessary; and it is the purpose of this paper to describe the work planned and done under the improvement program. The mines of the district have been frequently described in various technical publications, so a description is unnecessary here. From a mine-ventilation viewpoint, compared with coal-mine ventilation systems, the problem is complicated by the fact that the workings to be ventilated are situated on a large number of steeply dipping veins which frequently intersect and are faulted, and also by the fact that the extent, or existence, of orebodies is not definitely known in advance of actual development work. For these reasons ventilation work cannot be planned in advance of actual operations, nor can such regular systems of ventilation as are used in working the more uniform and continuous bodies of coal be developed. When operations are conducted at a normal rate, about 10,000 miners are employed on two shifts, so that about 5000 men will be underground at one time. But as ventilation is necessary to reduce high temperature and humidity due, mainly, to natural causes, the quantity of air per man per minute is not a governing consideration in determining ventilation requirements. Most important among the numerous sources of heat and humidity in the mines are: heat generated during decay of mine timber; heat and humidity given off by mine rock and water; heat generated by oxidation of sulfide minerals; heat given off by electrical equipment; heat generated by mine fires (in certain localities).

Jan 1, 1923

By L. C. Raymond

Valuations in the mineral industry differ from those of other enterprises because mines and oil wells have a definite life so cannot be considered a perpetuity. This requires that in any mineral-property evaluation the recovery of invested capital is necessary during the life of the property. Capital writeoffs for nonextractive industries are assumed to be continuously plowed back to sustain the operation and produce yields on the capital invested. The extractive or mineral industry, however, generally attempts to return to the investor both interest and principal during the life of a property. Normally this is done currently and the dividend includes both items. Where the mineral properly possesses large reserves and the life factor approximates a perpetuity, the return on investment is generally comparable to that of industrial stocks. The valuation of a mineral property, at best, is based on educated estimates and judgment factors. This is particularly true as it relates to estimating selling prices over a long term or assessing the quality of management. Also, it is possible to make various assumptions as to rapidity of working out the deposit, varying time for start-up of operations, varying earning rates, so as to obtain different results with the same basic facts. Thus it is not surprising that two engineers, irrespective of their abilities, may not agree exactly even when given the same facts, but their results should be close enough to be used in establishing a fair value for trading purposes. The valuation is no better than the source of basic data and the soundness of judgment factors. Fundamentally the basic principles of mineral valuation are similar for base metals, sulphur, oil, or any other mineral. Each mineral, however, requires an engineer to have a knowledge of such factors as its occurrence, distribution, mining and processing methods, and marketing problems in order to gather and analyze all the facts and data that have a bearing on the earning potential of the property. PRESENT VALUE OF A MINERAL PROPERTY In essence the present value of a mineral property is a sum of money in today's dollars that future earnings from the property are worth. It differs

Jan 1, 1964

By H. A. Baumann, A. J. Rostosky

EVER since the first installation of wet-washing methods of coal preparation, the removal of the water added by the washing process has created serious technical and operating problems. The rapid development and widespread adoption of wet washing has necessitated a corresponding development of dewatering methods and equipment. The amount of water retained by coal varies with the size of the coal. The moisture that is largely on the surface of the particles is easily shaken off coarse coal; thus coarse coal can be dried comparatively easily and quickly. Fine coal presents a larger surface area than does coarse coal, so its capacity for retaining moisture is greater. In fine coal, moisture below about 5 per cent is held between the coal particles and its removal is difficult. Draining and drying of the finer sizes is a major problem at many washeries. Two common problems of coal-washing practice that are intimately connected with dewatering and drying are the clarification of washery water and the prevention of stream pollution. The first field has been studied from many angles, including the use of coagulating and settling agents followed by vacuum filters to remove the solids, and the use of sludge tanks with dewatering screens incorporated therein. In many districts, the disposal of sludges into streams has been stopped by law. The lack of space for impounding sludges has created problems of disposal in other districts. Reduction in moisture means a saving in freight costs as well as the elimination of difficulties in unloading and storing. Excess moisture in coal causes it to freeze in localities where severe climatic conditions pre¬vail. Excess water in coals to be used in the production of coke and manufactured gas has a chilling effect on the walls of the oven or retort. Dryness of coal is important in producing good briquettes.

Jan 1, 1943

THERE are two general types of scientific approach to a problem. One approach, which is the more widely known, involves an analysis of the situation at the beginning of the experiment; this is followed by an analysis of the situation at each instant of time during the experiment and leads to a-detailed description of the prevailing conditions at the end of the experiment. Suppose, for example, we wish to predict the final rest position on a billiard table of a ball moving initially in a certain known direction with a known speed. The obvious approach is to estimate or measure off its course by consideration of angles of rebound, taking account of the "English" or spin if necessary and finally estimating from experience (or calculating from coefficients of friction) the slowing down occasioned by friction, thus establishing the point of the course at which the ball may be expected to stop. Any interference with the calculated course occasioned by collision with an unanticipated object would obviously cause us to revise drastically our estimate of the rest position. This general method of approach characterized by detailed description of how one situation developed from another seems intuitively appealing and is the most widely known method. There is no doubt that it gives very satisfying results when it can be used. There is a second general method of approach. In this method, the final state of a system is predicted from knowledge of general broad principles and their application, considering only the restrictions imposed upon the system. It is unnecessary to follow the course in detail; intermediate steps are not even considered. For example, if the billiard table mentioned in the first paragraph were tilted to one corner, one could predict that the final resting place of the ball would be in that corner; this prediction can be made independent of any particular course the ball may follow. This second general method of attacking problems is the one used in thermodynamics. There its use is so outstand-

Jan 1, 1951

NEW MEMBERS The following list comprises the names of those persons who became members during the period of July 10, 1917, to Aug. 10, 1917. ARNOT, STANLEY L., Engr., Plymouth Cons. Gold Mines; Ltd., Plymouth, Amador Co .2 Cal. BARRETT, LESLIE PARK, Asst. Geol.... Michigan Geological Survey, Lansing, Mich. BENNIE, JOHN WILLIS Gen'l. Mgr., Shannon Copper Co., Clifton, Ariz. BRINTON, OWEN FUGATE Mgr., Admiralty Zinc Co., Quapaw, Okla. BRODERMANN, JORGE, Civil Engr., Compania Minera San Francisco, Havana,Cuba. BROWN, RICHARD HENRY JR., Sales Engr., Ingersoll Rand Co., 300 N. Broadway, St. Louis, Mo. BROWN, STANLEY Chile Exploration Co., Chuquicamata, Chile. BUDDECKE, WILLIAM A Pres., Point Milling & Mfg., Co. Mineral Point, Mo. BURGESS, GEORGE K., Physicist and Chief, Division of Metallurgy, Bureau of Standards, Washington, D. C.

Jan 9, 1917

By Richard D. Hagni

Although the ore microscopist routinely examines polished sections to determine the mineralogy and texture of ores, his importance to the solution of problems peripheral to geology is not always fully realized. The techniques which he uses can be applied with little modification to the solution of a wide variety of beneficiation problem. By extending his studies beyond those normally considered to be of interest to the geologist, he can include examinations of polished sections of selected mill products. This is a logical extension, because the minerals and textures in the polished sections of ores are the same as those in millproducts. The mill dressing engineer should be more aware of the types of beneficiation problem that can be solved by the ore microscopist and what the ore microscopist can do for him. A greater degree of cooperation between the ore microscopist and the mill dressing engineer can be of significant mutual benefit. Ore microscopy holds an advantage over chemical analysis, because the interrelations and combinations ofthe mineral constituents of an ore or mill product can be visually determined. This advantage provides solutions to many beneficiation problem. Locking is a type of beneficiation problem that is particularly amenable to ore microscopy. The percentage, type, and distribution of locked particles can be readily determined with the aid of an ore microscope and an estimate made of the extent of additional grinding required for liberation. The extent of intimately locked types, which no reasonable amount of grinding will liberate, can also be evaluated. Mineral coating conditions, free particles of a deleterious mineral, and free particles of a valuable mineral held in flocculated clusters of gangue are other features that can readily be observed. In some instances, visual examination may show that the problem is not one of locking. Photomicrographs illustrate the variety of beneficiation problems for which the ore microscope is applicable. These problems and their resolution demonstrate the importance of the instrument and show the value of close coordination between the mill dressing engineer and the ore microscopist.

Jan 1, 1979

By Alan M., Bateman

MR. JORALEMON'S dispassionate discussion of this subject in TECHNICAL PUBLICATION 340 of the Institute shows clearly some of the failures and successes of geology in the discovery of ore deposits. He forces us to recognize, with humility, that chance has played a greater part than geology in the recent discovery of several great copper deposits. I think, however, he wrongly ascribes to unexpected or chance discovery some deposits that were found as a direct result of geological investigation. I refer to the Rhodesian copper deposits,, particularly Roan Antelope and Mufulira, both mentioned by him as having been found by chance. Also,. I think Mr. Joralemon's paper, inadvertently, does not- give the proper credit for the early recognition of the possibilities of these deposits. I feel sure that Mr. Joralemon and the gentlemen given credit by him will welcome any further information on this subject that will throw light on what will some day- be of. historical interest and importance. Consequently, I should like to set forth some additional data that throw light on who should receive the most credit, and' to indicate that, in my opinion, sound. geological reasoning and not chance is to be, credited for the development of the. Roan Antelope and Muf ulira mines.

Jan 1, 1931

By E. C. Harder

INTRODUCTION THE situation in the United States, at the present time, regarding the supply of manganese ores and alloys of manganese is one of great seriousness and is likely to become increasingly so while the European war continues. The two principal iron-manganese alloys, ferromanganese and spiegeleisen, are indispensable in steel manufacture, being used extensively in the Bessemer and openhearth processes.. Spiegeleisen, the lower alloy, contains between 15 and 25 per cent., and ferromanganese, the higher alloy, between 60 and 80 per cent., of manganese. Besides manganese the alloys contain iron and carbon. On the market ferromanganese is usually quoted on the basis of 80 per cent. manganese, and spiegeleisen on the basis of 20 per cent. manganese. The consumption of ferromanganese has been increasing during recent years at the expense of spiegeleisen, because larger quantities of the latter must be used to ac-complish the same purpose with the result that the amount of carbon introduced with it into the molten metal is frequently injuriously great. Manganese ore proper, in the form of manganese dioxide, is used extensively in many chemical industries, especially for oxidizing purposes. It is also used for the manufacture of both wet and dry electric cells and in the manufacture of paints and dyes. The manganese ore used in this country has been derived hitherto from three principal sources:. Southern Russia, Southern British India and East Central Brazil. The following tables show the quantity of manganese ore imported from these countries, and (for comparison) the domestic production, during 1912, 1913 and 1914. The imported manganese ore has been used largely in the manufacture of iron-manganese alloys and in addition large quantities of the alloys themselves have been imported, chiefly. from Great Britain, Germany and other European countries.

Jan 5, 1916

By J. W. Graham

For many years the author has been cognizant of the difficulty encountered by some in treating with the water influx formulas for unsteady-state fluid flow as pertain to the material balance equation. This has particularly applied in establishing reservoir performance and identifying reservoir pressure, which to the practicing engineer has entailed a trial-and-error procedure, and for others has necessitated resorting to computing devices and reiteration processes. In retrospect this difficulty stems from the fact that reservoir pressure in the material balance formulas, as well as associated with the water influx equations, is an inexplicit term, and the work reported in the past is irrefutable. However, what will be presented in this paper is another approach to the problem, whereby the entire material balance equation will be treated by the Laplace transformation, and reservoir pressure which hereto has been inexplicit, can now be isolated by mathematical procedure to relate that parameter with all the factors contributing to its change. This is the simplification entailed, that treats first with an undersaturated oil reservoir as an integrated effect from the inception of production. The second phase pertains to saturated oil reservoirs that encompass a survey traverse. Although both methods of approach are necessarily different in aspect, the most interesting fact is that the mathematics so deduced are identical. Both the linear and radial water-drive systems are incorporated. for which an illustrated factual example is offered for the latter, treating with a saturated oil reservoir. INTRODUCTIO N What is performed in this work is the simplification of an involved computation by advanced analysis. Although such may be construed as a contradiction when one treats with higher mathematics; nevertheless, when direction is given to such an undertaking the results car. be most revealing. Likewise, it is to be mentioned that the bases for these mathematics have been developed on the expediency of the occasion. This is not to be inferred as a qualification of this work, but rather the demands frequently placed upon the author in his private prac- tice in meeting a time limit. A situation, instead of being fraught with hazards, often has given emphasis to creative thought. What will be entailed in this work is the simplification of the material balance formulas by the Laplace Transformation., Although this reveals entirely new horizons that will be given expression in a forthcoming tract, it suffices in the present instance to limit our attention to this phase of the development that treats both with an undersaturated and saturated oil reservoir. To orient the reader's thoughts as to what is involved in this simplification is the recognition that reservoir pressure, as such, is an inexplicit term in the material balance equation. This is the independent parameter that defines the total history of performance in the author's' unsteady-state water influx formulas, as well as the basis for the physical dependency of fluid behavior within the formation as prescribed in the Schil-thuis' material balance equation. Therefore, to isolate reservoir pressure, which is the most essential factor in any reservoir study, is rather a cumbersome procedure entailing either a trial-and-error calculation for the engineer; or as some prefer, a reiteration process performed on a computing device. However, once such an equation can be transcribed as a Laplace transformation, this inexplicitness so expressed can be alleviated to identify reservoir pressure as an explicit function of all the factors contributing to its change. This is the simplification encompassed, that will treat first with an undersaturated oil reservoir as an integrated effect from the inception of production, and secondly, with a saturated oil reservoir as a survey traverse. Although the two approaches are necessarily different because of the uhvsics involved. it is an interesting commentary that the mathematics are identical, showing the interdependency of the two methods. In order to acquaint the reader with this development, the simplest case will be treated first; namely, an under-saturated oil reservoir subject to a linear water drive. However, what may be construed for this example as an idealistic case is actually a most practical application in certain parts of the world, where the size of the fields are so large that radial water-drive approaches the configuration of a linear drive. Further, to avoid the repetition of much symbolism, frequent references will be made to the work of the author and an associate on Laplace Transformations3,

By R. C. Craze

This paper discusses the characteristics of the velocity logs now available to the petroleum industry, and some of their advantages and limitations. The velocity log was designed as an aid to the geophysicist to determine velocity layering in the earth and to provide fast, accurate and economical vertical travel time data. After a number of logs had been made, studies were carried out on their use ia correlating strata in adjacent wells. It was found that adjacent strata usually show sufficient velocity contrast to make it possible to correlate these from well to well, even in areas where electric or radioactive logs fail.' In addition, velocity logs have been useful in the determination of porosity and thickness of reservoir rock.' These uses for velocity logs require an understanding of the characteristics of the log in response to the changes in velocity and in borehole conditions encountered normally in logging. GENERAL DISCUSSION OF INSTRUMENTATION The measurement made in velocity logging is more accurately described as a measurement of time rather than velocity. Ideally the log is obtained by measuring the length of time required for compressional sound waves to travel through a fixed distance in the formation. In practice, the time measurement may be made accurately but the distance through which the waves have traveled may vary slightly. Changes in borehole diameter are responsible largely for the difficulty in maintaining a fixed distance, especially if the diameter variations are so abrupt and frequent that the borehole instrument cannot follow contours of the hole. Several service companies have velocity logging equipment available or under development which have different transmitters, receivers, and measuring systems. While these differences are important, there are actually only two systems in use at the present time (Fig. I)."' The first system initiates a pulse at a trans-mitter and detects it at a single receiver. The transmitter and receiver are separated by a fixed distance, called the spacing. The time measured is that between the initiation of the pulse and the first arrival of acoustical energy at the receiver. The second system uses two receivers and a transmitter. The receivers are separated by a fixed distance and the time between arrivals of energy at the two receivers is measured. Here, the spacing is the distance between receivers. The two systems have much in common for it is possible to record both logs simultaneously. Usually the transmitter is an electro-mechanical transducer which produces discrete

By F. W. Davis

SOME idea may be gained of the tremendous consumption of refractories by the open-hearth steel manufacturers from a statement made by A. T. Green at a meeting reported by T11.e Industrial Chemist of London, as follows: "At a very progressive steel plant in the Midlands, with a battery of five open-hearth furnaces working. twelve months and making 3000 tons of steel per week, the cost of refractories per ton of steel produced averages about $0.50 for the actual open- hearth casting and $0.12 for those operations incidental to the rolling of the metal." .These figures, when translated into the annual tonnage of steel, represent a very considerable expenditure.

Jan 1, 1930

By Albert Stazicker

AT Climax the warehouse department operates as an independent unit similar to the mine and mill departments. It has the responsibility of receiving, checking, unloading, and storing all material and supplies delivered to the plant. In addition, the transportation of all supplies comes under the direction of the warehouse so that prompt delivery of supplies to all departments is one of its major functions. The transportation division operates heavy and light trucks, trailers, two large tractors, and two snowplows. In addition to delivering supplies it is also responsible for snow removal from the roads, hauling of sand and gravel for concrete and domestic coal to employees. and all miscellaneous work involving the use of tractors or trucks.

Jan 1, 1946

By V. R. Garfias, A. C. Fernandez

Despite artificial curtailment in all the fields of Mexico during 1937, owing to strikes and other disturbances, the production of crude petroleum aggregated approximately 46,738,000 bbl., showing a substantial increase of about 5,571,000 bbl. over the preceding year. Most of this increase occurred in the Poza Rica area, where, although only two wells were completed during the year, production increased from 14,162,000 bbl. in 1936 to 18,634,000 in 1937. While production in the South fields (Golden Lane) remained practically stationary, the output in the heavy-oil district of the Northern fields showed an increase of 1,930,000 bbl., because production had been considerably curtailed during 1936. Production in the Isthmus of Tehuantepec decreased about 596,000 bbl., owing to labor disturbances. Crude run to stills in local refineries increased from 34,000,000 bbl. in 1936 to 36,650,000 in 1937. Exports of crude and refined products were approximately 22,700,000 bbl., or 500,000 bbl. less than in 1936. Domestic consumption, excluding ships bunkers, reached a total of 20,000,000 bbl., which shows a small increase of 200,000 bbl. over the. previous year. Domestic demand for gasoline is estimated at 3,400,000 bbl. for the year, which represents an increase of 500,000 bbl. over 1936. In all, 60 wells were completed in Mexico during 1937, as compared to 70 in 1936 and 74 in 1935. In proven areas 52 completions resulted in 25 producers and 27 failures. In the Northeastern area near the United States border, five gas wells were drilled, all of which were producers; one of them, in Camargo, came in with a daily production of 20,000,000 cu. ft. of gas. One well, resulting in a failure, was drilled in Las Uvas, Coahuila, and three wells were completed in Quebrache, to the southeast of the heavy-oil district, resulting in two small producers and one failure. TWO more wells drilled in San SebastiBn, east of the Golden Lane, were failures. Fields Northern Fields (Heavy-oil District).—A total of 11 producers and 22 failures was completed in the proven areas of the Northern fields, as compared to 16 producers and 25 failures in 1936. In the Altamira

Jan 1, 1938