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By Leonard P. Colvin

Like all successful American enterprises, the mining industry is constantly trying to increase production, lower costs and improve working conditions. Companies are, of course, intensely interested in new equipment to help them gain these important ends, and one recent development-the mechanical raise climber--contributes to all three goals. Properly used, it increases production, cuts costs and has a number of important safety aspects all of which are the subject of this article.

Jan 1, 1962

By F. F. Craig

A series of both welter and gas puttern Hoods was made in the laboratory to study the oil recovery performances of .such operations. These tests were contlrrctt~tl on consolidated sandstone models, using oil. water, and gas. The model floods were scaled to reprotlrrce field performance under gas arid water five-spot injection. X-ray shadowgraphs permitted observation of the gross fluid movement within the models. A method was developed for applying the mobility ratio concept to water flooding and dispersed gas drives in a five-spot well pattern. The area1 sweep efficiency. tit breakthrough for dispersed gas drives is much higher than previorsly expected, Iying in the range of 50 to 100 per cent. A method is presented for predictitig the water-oil ratio performance of five-spot pattern water flood., in uniform sands. This method is verified experimentally for the cotidition of 120 free gas initially present and for va1ues of gas saturation normally encountered in fields following depletion operations. Prodrrction perfort?zut~cc for pattern gas injection is also predictable by this method. INTRODUCTION In field pattern hater flooding or dispersed gas injection operations, the displacing fluid (water or gas) is injected and oil is produced through wells which are, area-wise. small openings in a large container or rescrwir of oil. As a result, not all of the area between the injection and producing wells is necessarily contacted by the injected fluid by the time it first reaches the producing wells. The question arises in predicting oil recovery. as to what traction of the pattern area involved is contacted by either the injected water or gas due to the relative position of the injection and producing wells. This is the areal sweep efficiency. It is also desirable to know how well arrangement affects the oil production performance. A solution to this problem has been attempted by many means. Mathematical analysis¹,²,³, and electrolytic models', have been used to establish a breakthrough areal sweep efficiency of 73 per cent for a five-spot pattern in which the ability of the oil to flow ahead of the invading fluid is equal to the ability of the invading fluid to flow in the invaded zone. All of these studies simulate only one of many field conditions. Improved studies of areal sweep efficiency at breakthrough were made using the fluid mapper5, poten-tiometric models" and X-ray shadowgraph techniques. In these it was possible to study the effect of variations in mobility of the injected and displaced fluids, and so to cover a wide range of field conditions. The limitation of these studies is that, with these models, it was not possible to simulate the saturation gradient behind the flood front when oil is displaced by gas or water. In the most recent published technical paperS on the subject, a method was presented for predicting the oil recovery performance after breakthrough in a five-spot pattern water flood. The method involved correlations which were obtained experimentally using miscible fluids. One limitation of this work was that a saturation gradient, usually found in immiscible fluid displacement, was absent in these studies. Also the laboratory studies did not cover the situation of a water flood following oil recovery by depletion drive. as is the situation in most field water floods. The tests reported in this paper were made using oil. water, and gas, thus eliminating the simplifications of former studies. Also reported are laboratory studies on

Jan 1, 1956

By Thomas V. Falkie

The three basic ingredients of fertilizers are nitrogen, phosphorus, and potassium. Nitrogen comes from natural gas or other sources and is usually a "manufactured" ingredient. Phosphorus and potassium come from mineral sources which are mined in open pit and underground mines all over the world. Phosphorus is one of the 15 chemical elements needed to sustain life. Along with nitrogen and potassium, it is essential to the fertility of the soil and to the growth of plant life. Plants require phosphorus for proper soil conditions, early root formation, and crop maturity. Humans and animals require phosphorus for bone and tooth development. The primary raw material for phosphorous fertilizers is phosphate rock. It is found and mined in many areas of the world. Morocco, the United States, USSR, Tunisia, and some Pacific Islands are the leading rock producers. Other sources of phosphate are guano, bone meal, and other natural organics, but these comprise a very small percentage of all phosphate used. Phosphate rock in the United States is mined in Florida, North Carolina, Tennessee, Idaho, and Montana. Florida alone produces about 70% of all the rock mined in this country, mostly from a 20 X 30 mile area in Polk and Hillsborough Counties in central Florida known as the Bone Valley district. There are phosphate reserves in many parts of Florida, and within the past three years mining has begun in north Florida in Hamilton Country (see Fig. 1). In 1967, world phosphate rock production was about 75 million short tons (st). The United States produced about 35 million st (about 47%) of which Florida produced about 25 million st (about one-third of world production). According to Phosphorus and Potassium magazine (Mar./

Jan 1, 1969

By Robert E. Green, Kenneth Reifsnider

Several experiments have been performed in order to illustrate the application of a recently developed X-ray image intensifier system to metallurgical investigations. In the present work the system has been used to study the instantaneous alterations in Laue transmission X-ray diffraction patterns during tensile deformation of aluminum single crystals. Expem'mental results are presented which demonstrate the capability of the system for crystal orientation, for following orientation changes due to lattice rotation during tensile deformation, and for showing changes in the homogeneity of the lattice planes along the specimen length as a function of strain rate. RECENTLY, a new X-ray system has been developed which incorporates a cascaded image intensifier and permits direct viewing and recording of X-ray diffraction patterns produced on a fluorescent screen.1"3 In the present work the results of several experiments are presented which demonstrate the usefulness of this system for metallurgical applications. EXPERIMENTAL PROCEDURE A schematic diagram of the experimental arrangement is shown in Fig. 1. In this system a Machlett AEG-50-S tungsten target X-ray tube, normally operated at 50 kv and 40 ma, serves as the X-ray source. The X-ray tube is placed in direct contact with a 10-in.-long collimator, which transforms the X-ray beam from one with a circular cross section to one with a rectangular cross section 3 in. high and 1/6in. wide. By blocking off all but a small portion of the rectangular slit, it is possible to work with the more conventional "pinhole" collimated X-ray beam commonly used for obtaining Laue diffraction patterns. In the present work the test specimens were 99.99+ pct aluminum single crystal wires & in. in diam and 3 in. long. For the deformation tests the wire crystals were mounted in a special set of grips in a table model Instron machine so that diffraction patterns could be recorded during specimen deformation. For the orientation tests the wire crystals were mounted in a rotating goniometer so that diffraction patterns could be recorded during specimen rotation. At a distance of 3 cm from the specimen axis, a 6 in. diam DuPont CB-2 fluorescent screen is positioned to transform the X-ray image to a visible one. A Super Farron f/0.87 72 mm coupling lens, corrected for 4 to 1 demagnification, transmits the visible image to the image tube. The image intensifier used is a three-stage magnetically focused RCA type C70021A with an S-20 input photocathode and a P-20 output phosphor. The tube has unity magnification and useful input and output screen diameters of 1.5 in. The image on the output phosphor is of sufficient intensity to be viewed directly, to be recorded cine-matographically, or to be displayed by vidicon pick-up on a television monitor. The recording device most commonly used is a 16 mm Bolex motion picture camera fitted with a Canon f/0.95, 50 mm lens. The overall gain of the system is 16,000 for direct viewing and 2240 for recording on 16 mm movie film. The resolution of the system is limited to 1 line pair per mm which is approximately that of the fluorescent screen. This system has been used for cine recording of transmission Laue X-ray diffraction patterns with exposure times as short as 1/220 sec and for vidicon television pick-up and display at a scan time of 1/30 sec. Quantitative information may be obtained from each frame of the movie film, by either stopping the vertical slit down to a point source in order to obtain a conventional Laue photograph or else by retaining the linear beam and introducing fiducial marks as described in a previous paper.4 In either case, each frame may be enlarged to appropriate size for analysis by either using a photographic enlarger and making prints of the desired frames, or, more conveniently, by using a microfilm reader. EXPERIMENTAL RESULTS The first series of photographs which are presented in Fig. 2 serves to demonstrate the usefulness of the system for crystallographic orientation determination. This series of prints, made from enlargements of a 16 mm movie film, shows the dynamic Laue transmission patterns produced by an aluminum single crystal wire which was rotating about the wire axis when the patterns were recorded. The movie films were taken at 16 frames per sec and the crystal was rotated at a rate of 15 rpm.

Jan 1, 1970

By H. F. Dawes

In China all minerals are, theoretically at least, the property of the Emperor, and the Imperial permission must be got from him for the privilege of working them. A direct tax is levied on this privilege, and by simple command, the Emperor can close a mine at any time. Occult geomantic influences are a large factor in determining the opening or the arbitrary closing of a mine. The location with reference to points of the compass, graves and natural objects, may be really or professedly considered as indicating that those influences are favorable or unfavorable. The consequence, is, of course, that for the authorization and encouragement of any considerable enterprise, friends' at court, practical politics, and more or less bribery, are required. As a result, most Chinese mining is illicit, and is carried on in a small way only. Often along a single vein, or over a small section of mining country, a few individuals obtain rights over all the openings, most probably by loaning money to the head-men of the operators and holding the mines as security for the debt. In such cases, perhaps, for better security, all the ore is reduced in the works established by the creditors, who also handle all silver produced..As the head-men are, for the most part, improvident, and the laws and customs for the collection of' debts are stringent and peculiar, the " officemen" or creditors acquire in time what is practically an ownership of

Jan 1, 1892

By G. C. Bateman

The Workmen's Compensation Act of Ontario was passed in 1915 and Miners' Phthisis was added to the list of compensable industrial diseases in 1916. Under this provision of the Act only about two cases were compensated per year. In 1924, The Department of Public Health made a survey of miners in the four principal camps—Sudbury, Porcupine, Kirkland Lake and Cobalt—and the survey indicated that an alarming proportion of the men exposed to dust had silicosis in one or other of its several stages. A number of conferences were held between representatives of the Department of Mines, the Department of Public Health, the Compensation Board and the mine operators. The operators were advised that in the earliest stages of silicosis there was no physical disability and if men in that stage were removed from underground there would be little danger of permanent disability. They were further advised that if active steps were taken at once to compensate men that had some real disability and remove from the mines men in the early stages of silicosis, the first cost would be the greatest and thereafter their liability should decrease. As a result of this advice, and having at that time no reason to doubt the findings of the survey, the operators agreed to do all that was asked of them and cooperate with the Government in the steps believed necessary to meet the situation, and to provide compensation for the men affected. Amendments in 1926 Arrangements were made for the necessary amendments to the Mines Act and the Workmen's Compensation Act and these amendments were passed in 1926. The Amendment to the Mines Act provided that all underground employees must be the holders of certificates certifying that they were free from tuberculosis of the respiratory organs and further provided that the certificates must be renewed annually. The Government, however, at that time refused to adopt a form of certificate for applicants certifying as to their physical fitness for underground work. The Amendments to the Compensation Act defined both silicosis and

Jan 1, 1937

Richard Moldenke, New Pork, N. P. (communication to the Secretary*):—Iu following the discussion of the specifications for cast-iron and finished castings, I mas strongly impressed with two points which might be ventilated to advantage more fully from the view of the practical foundry-man. First, the reasons why only silicon and sulphur were specified and not phosphorus, manganese and carbon; and second, why but little was said concerning the presence of iron oxide in the material.

Jan 1, 1905

By E. F. Poncelet

Forty years ago A. A. Griffith developed a theory explaining why brittle materials displayed such low tensile strengths.' He based his views on two points. First, he found himself compelled to assume that all brittle materials are replete with flaws, cracks, and other defects that act, although quite invisible, as large stress raisers. Second, he applied the "theorem of minimum potential energy," which says that the total potential energy of a system must pass from the unbroken to the broken condition by a process involving a continuous decrease in potential energy. By this means he satisfactorily accounted for the noted low strength of such solids and also for the wide spread obtained in experimental measurement of these strengths. So successful has the theory been that it is favored by some to this day. Unfortunately this theory is of limited use beyond the explanation of these two noted phenomena and it is keenly felt that a better theoretical insight into the physics of the fracturing process is needed as the volume of experimental evidence accumulates. The author proposes in the following to build on the fundamentally sound concepts of Griffith and, with the help of increased theoretical knowledge over that available to Griffith, develop a mechanism for frac-ture which will provide far greater understanding of the experimental evidence accumulated to date than is possible from the original Griffith idea. THE GRlFFlTH THEORY Very little progress indeed can be made without accepting the first postulate of Griffith which supposes all brittle solids to be full of microcracks. It would be difficult indeed to find a better mechanism for the small strength of such brittle materials, in conjunction with the fact that the energy that must be expended for comminution is by no means small. The postulate of the existence of the microcracks permits the breakup of the various bonds a few at a time by concentrating the stress at the tip of the progressing crack, while the total energy expended is the same as if they all had been ruptured simultaneously. The only flaw in the argument is that no reasonable explanation has been proposed to account for the genesis of such cracks. Indeed their very presence is in violation of the Griffith second postulate, the potential energy theorem. This theorem is straightforward for isothermal processes, and, in spite of Griffith, there is some doubt that treating the problem isothermally is legitimate. The surface energy of bodies is a free energy, not a potential energy as stated by Griffith, and the production of new surface free energies is not necessarily an isothermal process. There is ample evidence to the contrary. Generally speaking, if heating a body increases its surface area, then, by virtue of Le Chatelier's principle, any increase of that area by other means will tend to lower its surface temperature. Lord Kelvin calculated the actual cooling that resulted in drawing out a film of liquid.2 R. A. Houston calculated the surface cooling that resulted in stretching a metal wire.3 These calculations were made by applying the Carnot cycle to the process and evaluating the thermodynamics thereof. IRREVERSIBILITY OF THE FRACTURING PROCESS While Griffith was very careful not to say so, the impression gained from studying his papers is that he considered the fracturing process as reversible, that is, a succession of quasi-equilibrium states. There is ample evidence that it is not. The indication that the new surfaces produced by the propagation of a crack are cooler than the original body points to an irreversible heat flow from the interior to the new surfaces to equalize the temperatures. If the process be reversible, any crack accidentally formed should immediately close up as, in the absence of any strain energy, the potential energy would thereby be lowered. The fact that they do not, constitutes a paradox. Such paradoxes are nothing new where certain phenomena that propagate from minuscule nuclei are assumed to be reversible. Such is, for instance, the condensation of a pure saturated vapor that is suddenly chilled by adiabatic expansion. At the beginning the tiny droplets that are formed should be only a few angstroms in size, but the vapor pressure at such droplets is so high that they should evaporate at once. A similar situation arises if a saturated pure solution becomes super-saturated upon cooling; the first tiny crystal nuclei should dissolve as fast as

Jan 1, 1964

By J. Price Wetherill

THE coal-seams that are worked vary from 32 to 100 feet in thickness, and occur at all angles of inclination, but are never flat for any great extent. They contain coal, slate, and an unsolidified coal, called dirt by the miners, in various proportions, a uniform seam of coal alone being rare. The upper walls are composed of conglomerate, sandstone, or slate; the first two hard and solid in texture, and withstanding the action of the atmosphere and moisture sufficiently well to offer but little trouble to the mining operations ; while the latter crumbles rapidly, owing, in part, to the decomposition of iron pyrites which it contains in large quantities, and in part to its own friable character, and requires constant care to avoid accidents to the men working below it, and to prevent its mixing with the coal mined. The floors are composed of slate. As in all mining operations, the. general system pursued is to reach with a permanent outlet such a point in the seam as will

Jan 1, 1877

IN the footnote on the first page of Prof. Stoek's paper, as printed in vol. xxviii. of the Transactions, I alluded to him, under an erroneous impression, for which he was in no way responsible, as " the present Director of the Scranton Schools." This incorrect statement placed him in a false position, as possibly having authorized the use of a title to which he had no claim. In fact, Prof. Stoek has never had any official connec-

Jan 1, 1900

By E. Beril

This may be a most unnecessary paper—from what does crude oil come and how was it formed. Many people, inside and outside of the petroleum industry, believe that we have actually enough oil, and that we can easily produce very important products from this extremely valuable raw material. The writer believes, however, that the answer to this question concerning the parent material and the formation of oil is of broader interest, because it may be that from the answer to these problems it would be possible to get answers to other important industrial questions. Therefore, a study in this line seems to be justified, and the writer will submit some of the results which he has collected during more than ten years with many very capable collaborators, to whom his thanks may be expressed on this occasion. Older Theories There is no doubt that plants were the parent material of coals, but opinion is divided as to the parent material of crude oil and asphalts. One group of specialists believed that they were formed from dead fish. The hydrocarbons of crude oil were formed by the splitting off of CO² from fatty acids formed by the saponification of the fat (glycerides) of fish. Enormous quantities of crude oil are present in many places on the earth, very often in several nonconnected horizons at the same location. This could hardly be explained by the so-called "catastrophe theory," which states that fish died through the entrance of salt water into fresh water, and vice versa. Furthermore, this theory cannot explain the presence of aromatic hydrocarbons, which can be found in nearly all oils, especially in the oil of the Netherlands Indies, which has more than 50 per cent of aromatics. Geological and chemical observations both lead to the belief that the temperature of formation of asphalt, crude oils and coals, perhaps with a few exceptions, did not exceed 200° C. Chlorophyll and haemin derivatives, which decompose above 200° C., have been found in all these materials by Treibs and others. Thermodynamic considerations show that the temperature necessary for the conversion

Jan 1, 1938

By Thomas M. Chance

All gravity methods for the separation of ore from gangue, or of slate and other refuse from coal, are based upon differences in the falling velocities, in some fluid medium such as air or water, of the materials to be separated. As all materials falling in a vacuum have the same velocity, independent of the size, shape, weight or specific gravity of their individual particles, it would be more accurate to describe the operation of these methods as depending upon the retardation of falling velocities effected by the resistance of a fluid medium, this retardation being greater for small or light particles than for large or heavy particles. This generalization is true also of those appliances utilizing centrifugal force to replace or to supplement the action of gravity. The separation of materials of different specific gravities by means of a fluid having a specific gravity greater than that of the lighter particles and less than that of the heavier particles has not been applied commercially, or on a large scale, to the separation of ores or to the washing of coal, the method being limited to laboratory experimental work or to laboratory determinations for the purpose of checking up the work of jigs, classifiers, and other types of concentrating appliances. A solution of zinc chloride has thus come into general use in the laboratory to separate coal, bony coal, and slate, both to check up the work of coal-washing plants and for the purpose of making tests preliminary to the designing of coal-washing plants. The use of a heavy solution of some chemical in water has often been proposed for making such separations, especially in connection with the washing or preparation of coal. Practically insuperable difficulties, however, have prevented the commercial development of any such process, the difficulties being both physical and financial. The cost of the chemical used to make high-gravity solutions is usually prohibitive, and the freeing of the coal from all traces of the chemical is found to be practically impossible. Such solutions inevitably penetrate the individual lumps and particles of coal, transfusing into the pores and saturating the joint-planes, and very large quantities of wash water

Jan 1, 1918

By C. L. Berrien

Many fires have occurred in the mines of Butte in recent years, and while all have been of a serious nature, simply because they were mine fires, six of them have been especially dangerous in respect to loss of life and property, and the expense of extinguishing or controlling them. It is not my intention to discuss the relative merits of methods used in fighting these different fires because the conditions under which they occurred varied in each case, and it was not always advisable to expend the large sum of money necessary to actually extinguish them if they could be bulk-headed off from the rest of the mine. It is needless to say that everything possible has been done to check all fires at the beginning, but without success in some cases; and it has then become necessary to bulkhead all connections to them, in which state several now exist. The mine fires of Butte, or fires in any mine, may be divided into two classes, namely: Those occurring in accessible workings, and those occurring in inaccessible workings; because these two conditions govern to the greatest extent the methods of fighting fires. Accessibility and inaccessibility in the case of mine fires concern not only new open workings and old closed workings, respectively, but also the condition of the ventilation in and about those places. When a fire is accessible at the start it should not be difficult to confine it to a small area and extinguish it in a relatively short time, but when it is impossible to actually reach a fire in old filled, abandoned workings, or there is no opening by which the gases may be conducted away from the fire zone, then the time consumed in changing those conditions permits the fire to increase to such an extent that it is a long, hard fight to overcome it. These different conditions have been met in Butte, and of the six fires of serious proportions the Steward mine fire and the High Ore-Modoc mine fire were in new accessible workings and were extinguished in a month or so. The Anaconda mine fire, the Leonard-Minnie Healy mine fire, the West Colusa mine fire, and the Mountain View mine fire, were all inaccessible. The Anaconda mine fie started about 25 years ago and though safely bulkheaded is still active. The Leonard-Minnie Healy

Jan 1, 1916

OPEN-HEARTH refractories are not merely an accessory to the furnace. They are the furnace, to all intents and purposes. The steel work of the main structure is merely an open frame which helps to support the refractories; and the regenerators, a necessary part of the furnace system, consist almost entirely of refractories. Not only do refractories constitute the essential part of the furnace, but they also carry the liquid steel all the way 'to the point where it begins to solidify. On leaving the furnace the liquid passes through a refractory runner into a refractory-lined ladle, then through a refractory nozzle closed by a refractory stopper on the end of a rod protected by refractory sleeve bricks. The liquid is sometimes sent through an additional refractory- lined tundish, a supplementary ladle, or a refractory runner for bottom pouring, until it finally enters the iron mold in which it solidifies. Even in the mold, refractory materials are sometimes used to provide a nonconducting "hot top." This series, from runner and ladle to hot top, inclusive, is often referred to collectively as the "pouring-pit refractories." REFRACTORY RAW MATERIALS The raw materials available are best classified into basic and acid types. The principal basic raw materials are magnesite, dolomite, and chrome ore. The principal acid materials are silica in various natural forms, and fireclay. Magnesite. Austria was the principal source of magnesite (MgC03) until recent years, when the Province of Quebec, in Canada, and the states of Nevada and Washington became important sources for the American steel industry. More recently these natural sources have been supplemented by the so-called "sea-water magnesite"-which is the name somewhat incorrectly given to magnesium hydroxide obtained as one of the products

Jan 1, 1951

By AIME AIME

AT a recent meeting of the Utah Section. A.I.M.E., P. D. Nielson, general plant superintendent of the new Geneva steel plant at Provo, Utah, spoke on "General Operations of the Geneva Plant." Mr. Nielson explained that the plant was located at Provo, Utah, on account of railroad facilities, the proximity of coal, iron, and limestone, and the nearness of water for operating the plant. Water probably was the most important item in making the decision.

Jan 1, 1944

By William Mikulas Lars Thomassen, Clair Upthegrove

Little work has been done in the field of the nickel-tin binary system. The complete diagram has been investigated on two occasions, but the results are in very poor agreement. The structure of a compound NiSn and the solubility of tin in nickel have been determined by X-ray methods. Several investigations have been made of the liquidus curve, and the compositions of the eutectics have been determined. A study of the literature, however, shows that there is no satisfactory agreement between the data presented in the various papers. The present investigation was undertaken in an attempt to determine the equilibrium conditions, and to correlate X-ray with metallographic data. The equilibrium diagram was determined by thermal and metallographic means, and the solubility of tin in nickel further investigated with X-rays. Powder diagrams were made of the intermetallic compounds, and three of the structures were partly determined. NO attempt was made to determine the range of homogeneity of the intermetallic compounds. Review of the Literature Vigorouxl prepared alloys of tin and nickel containing 74 and 92 per cent of tin. By treating these alloys with very dilute nitric acid or with sodium hydroxide he was able to separate residues, both of which analyzed 66.7 per cent tin. This corresponds to the compound NiSn and was reported as such. Guillet2 made the first investigation of the complete binary diagram Fig 1) The maximum point of the liquidus is at 43.5 per cent nickel. Several solid solution areas were found, and the compound NiSn was included on the strength of Vigoroux's work. The investigation was

Jan 1, 1937

By V. L. Minear

This paper presents some of the problems encountered and solved by the construction industry during recent years while pressure grouting the foundation rock of dams. Pressure grouting has become "Standard Operational Procedure" and consequently many hundreds of thousands of bags of cement have been used for that purpose. There is nothing weird, mystical, or even particularly difficult about the basic idea. Holes are drilled in the rock and grout is pumped into them. This procedure is used to shut off the flow of water under the dam and to reduce the uplift on the dam. Like most other engineering and construction problems, the fundamental principle is simplicity itself, but some of the "minor details" are rather complex. When faced with the problem of actually forcing the grout into the rock, or keeping it there once it has been injected, an engineer frequently has need for all of the ingenuity and initiative that he has at his disposal. It is proposed to discuss these minor details at length, even at the risk of boring the reader. The difference between success and failure in a grouting program can well hinge upon some such detail that may not be fully understood. Pressure grouting is a method used to make good foundations from bad ones by plugging actual or potential passages within the rock through which water might escape and thereby diminish or even destroy the usefulness of the dam. In some special cases, pressure grouting has been used for the purpose of consolidating broken rock to increase its bearing power. Lacking this useful method, many of the dams constructed during recent years could not have been built. Most of the really excellent dam sites in this country have been utilized long ago. Consequently it becomes necessary to find methods of utilizing the less desirable sites. Pressure grouting plays a vital role in the methods developed. Engineers have learned the hard way, that the term "solid rock" is a misnomer. Solid rock does not exist to any considerable extent in nature. Practically all rock contains imperfections such as shrinkage cracks, bedding planes, joints, solution channels, folds, shear zones, crush zones, and the like. All these imperfections are weaknesses through which ground water is likely to flow. The function of rock grouting is to rectify these imperfections and make the rock as nearly "solid" as practicable. The location, direction, depth and number of grout holes to be drilled are important. Clearly, a hole must pierce fractures in order to serve a useful purpose, for grout cannot be forced into the rock itself. Were it possible to determine the pattern and extent of the cracks within the rock, it might be feasible to drill two or three strategically placed holes so as to make practicable the grouting of the whole integrated network of cracks from them. Such is not the case. While a study of the geology, surface indications, and drill cores is helpful in gaining an idea of subsurface conditions, in the final analysis, the seams must be located by trial and error methods. There can be no doubt that the closer the

Jan 1, 1949

By G. E. Burpee

A COMPREHENSIVE study of insoluble residues in the productive Permian limestone in the Hobbs and Eunice fields, Lea County, N. M., has been conducted by Shell Petroleum Corp. engineers {luring the past two years. This study was prompted by the belief that the stratigraphy of the producing formation might be worked out in detail and that some relationship might be established between the permeable oil, gas, and water zones and correlatable lithologic horizons within the productive formation. As a result of the study, correlations have been established which have proved of great value to both an orderly development and corrective program.

Jan 1, 1935

By L. C. Morganroth

From a geological standpoint, but scant attention has been paid to fire-clay beds. Only within the last few years have they been the subject of individual investigation, prior to this time having been considered only in their relation to coal seams. While the relative importance of coal and fire clay is still immeasurably in favor of coal, yet an industry as large as that of fire clay is entitled to a measure of attention. A discussion of the Carboniferous clays is practically a discussion of the clay beds in the Appalachian basin, since more than 90 per cent. of these clays mined are from this region. The clays are confined to the northern end of the basin, or the States of Pennsylvania, Ohio, Kentucky, Maryland and West Virginia, ranking in importance about in the order named. The clay deposits of the Carboniferous period have been divided into two classes; those found in the Pottsville conglomerate series of rocks, ' and all those that are found in the formations above, for the reason that the clay beds above the Pottsville series all resemble each other in properties, composition and appearance, and all are distinctly different from the bed found in the Pottsville formation. The bed of clay found in the latter formation is unique in that flint clay is practically restricted to it. (A variety of flint clay is occasionally found in these upper deposits but this is in such small amounts as to be negligible.) Carboniferous clays occur between stratified rocks; sandstones, limestones, etc., in the same manner as coal veins. They are often accompanied by a coal vein although where the clay is of a workable thickness, the coal is generally too thin to work. The clay beds are sometimes known by the name of the coal seam at which horizon they occur. Clay beds may be from a few inches up to 20 ft. in thickness. They may consist of all soft clay, all flint or both soft and flint. The Carboniferous clay beds of Pennsylvania are the most important of any of the clay beds found in the country, and are among the oldest ones worked. We know more about this clay geologically for the reason

Jan 1, 1916

By JOHN R. SUMAN

I WOULD like to spend a few minutes describing to you the present condition which exists in the oil industry and then point out some aspects of this deplorable situation in which I think petroleum engineers can be helpful. As you know, the oil business at this time is in a very critical condition, .due to the tremendous potential production in excess of current demand. This is a world-wide condition as well as a national problem, as it is estimated that the surplus production available for the market in foreign countries is of about the same proportion as that existing in the United States. Due to the inability within the United States to hold production within the bounds of demand prices have been slumping for the last four years and at this time have reached the point where the sales value of the average barrel of crude oil in the United States, is far below the cost, of production. In addition to the large amount of potential production available for the market in excess of demand we have in storage in the United States about six hundred fifty millions of barrels 'of oil. Unless something can be done to limit the amount of oil coming onto the market to a point well below the demand, which point will permit the reduction of stocks, it looks as though the 'oil business is facing demoralization.

Jan 1, 1931