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By Earl Oliver

Dean Roscoe Pound, of Harvard Law School, in addressing the A.I.M.E. Petroleum Division on Feb. 22, 1934, said, "When you are able to work out a program that is mechanically feasible, that is economicaIly advisable, and which seems in your judgment, which is just as good as that of anyone, to be politically wise, you will not have very much trouble in the end in inducing the courts of today to find that it is legally sound." The purpose of this paper is to show: first, legal conditions necessary to promote conservation and stabilization; and second, to suggest operating procedure when those legal conditions are established. The proposal is mechanically feasible and economically advisable. A growing public understanding should make it politically wise. The disappointing progress in the development of conservation and stabilization can be attributed to the lack of two legal concepts as integral parts of oil and gas law; i.e., (1) a practical substitute for the capture rule, (2) collective ownership control for the individual oil and gas pool. When these two concepts are established on an equitable basis, conservation and stabilization procedure will become a comparatively simple process, more or less automatic in its adaptation and operation. Establishing these concepts is the function of the law-making agencies and might well be left to them for discussion except that the mechanical processes that give them form and substance must first be developed by the engineer. A Substitute for the Capture Rule Much has been written on these subjects, but the most concrete statement that has come to the attention of this writer is the following from an article by Charles G. Haglund in the Kentucky Law Journal of May, 1934: The Oxford1 case is not only authority for the proposition that it is competent for the legislature to modify the old property law of capture with respect to oil and gas but that it may also delegate such authority to a subordinate body.

Jan 1, 1935

By F. W. McQuiston

Teamwork is the key to an efficient organization. Cooperation among mining staff members is an obligation owed to the company. The more cooperation the metallurgist receives from underground, the higher milling yield will be, which in turn makes for a greater mine profit. There is no pay for metal left in mill tailings. The metallurgist is not in a position to be of help to either the geologist or mining engineer, but can receive valuable assistance from both. Therefore, the metallurgist must win underground cooperation. The mining engineer is usually interested in geology because of its relation to ore control; in milling because that is where the rock goes. However, any overlapping of interest between geologist and metallurgist is quite remote.

Jul 1, 1956

By D. H. Polonis, J. G. Parr

IN a recent paper on titanium-rich Ti-Fe alloys,' the hardness of quenched powder specimens was given, together with the amounts of martensitic a they contained. The values disagreed in two respects with previous determinations that Worner² made on lump specimens: 1—Some martensitic a' is formed in powder specimens of alloys containing up to 12 atomic pct Fe. On the other hand, Worner reports that, although his results on quenched lumps are not conclusive, alloys containing more than about 4 pct Fe "appear to consist of retained ß'' although they "may not be strictly unaltered solid solutions." 2—According to Worner, quenched lump specimens show a maximum hardness at a composition about 3.5 pct Fe. Earlier -experiments by the authors showed a maximum hardness of martensitic alloys in powder form at 10 pct Fe. Accordingly, more experiments have been conducted in order to confirm these differences and to determine with more accuracy the minimum composition of quenched lump specimens that consist entirely of retained ß. Lump samples?x?x1/20 in. were quenched from 1000°C in helium and, on the whole, showed similar hardness values to the specimens that Worner water-quenched from 950°C. The hardness curve the authors obtained shows a more pronounced peak, but in other respects it is very similar to Worner's curve (Fig. 1). While it was possible to make fairly reliable measurements of the percentage of martensitic a in quenched powders (by Geiger spectrometer), the solid samples allowed only approximate estimates to be made from visual observation of line intensities on film. Retained ? begins to appear in quenched lumps containing 0.2 pct Fe; at 2.2 pct Fe there are approximately equal quantities of ß and a'; in a 4.7 pct Fe alloy only a trace of a' appears. These results are represented as a curve on Fig. 1. The hardness and constitution of powder samples were verified by repeating both types of quenching experiment described in the earlier paper.' Identical results were obtained by the two methods, and they agreed with the figures published previously (Fig. 1). The appearance of the martensitic structure under the microscope is shown in Figs. 2 and 3. The mar-tensite needles are coarser in the lump; otherwise the structures are similar. Three conclusions are made at this juncture: 1— The properties of quenched lumps reported by Worner are confirmed, on the whole. The differences between them and the properties of powders are probably due to an effect of specimen size. Differences of behavior in various sizes of specimen have been observed previously in martensite reactions in Fe-Mn alloys3 and in Cu-A1 alloys. 2—The maximum hardness of both quenched lumps and quenched powders appears at a composition where martensite formation has all but ceased. In this respect, powders and lumps behave similarly. 3—Martensitic a' has essentially the same microscopic appearance both in powders and lumps. Acknowledgment This work is part of a program sponsored by the Defegce Research Board of Canada, Project No. 425.

Jan 1, 1956

By C. E. Sims

In some experimental work conducted several years ago, it was noted that sulphur seemed to have a distinct influence on grain size of carbon steels. 111 order to check this observation, a series of S..A.E. 1040 steels was made with the normal composition held as nearly constant as possible. The steels were made with three sulphur levels, which were 0.012, 0.024 and 0.038 per cent sulphur, respectively. For each of the sulphur levels, steels were made with only silicon deoxidization and with aluminum additions of 0.1015, 0.025, 0.050 and 0.10 per cent. The melting medium was an acid-lined high-frequency induction furnace. These steels were forged and rolled and differentiall!. quenched from temperaturcs in the range of 1500O to 1800°F. After this, the A.S.T.M. grain size was determined and plotted as in Fig. I. It will be noted, first of all, that the aluminum-free steels had filler grain size with higher sulphur when heated to 1500, but that this condition was reversed at 1700°. When aluminum was added to produce fine grain size, the steels in the lowest sulphur level were fine-grained only to 1600°. and then only with an addition of one pound of aluminum per ton. The medium sulphur steels werc fine-grained to 1600' with a wider range of aluminum addition. The steels in the highest sulphur level were fine-grained at 1600° over a still wider range of aluminum additions and fine- grained at 1700° with an addition of one pound per ton. Fig. 2 shows curves of the grain-coarsening temperature for these steels and illustrates how sulphur and aluminum combine to give greater inhibition to grain growth than aluminum alone. Only the highest sulphur steels have a grain-coarsening temperaturc above 1700°.. At 1650°, the low sulphur steel is fine-grained only at its peak, while the highest sulphur steel is fine-grained over a wide range. In these tests, one pound of aluminum per ton gave the best results; this is equivalent to about 1 1/2 lb. per ton for commercial condition. IllcQuaid-Ehn tests made on these steels showed the same trend but to a lesser degree. The tests were repeated on a series of S.A.E:. 1015 steels with sulphur levels of 0.02 and 0.03j per cent. Aluminum additions were made in the range from 0.025 to 0.15 per cent. These steels were forged and rolled, normalized at 2000°F. to put them all in the same starting condition, then reheated to various temperatures from 1600" to 1800" and cooled at rates that would allow ferrite precipitation in the austenitic grain boundaries. The results of these tests arc shown in Fig. 3. It will be noted that. up to the temperature of 1650°, there is very little difference in the grain size obtained from the two levels of sulphur. .At temperatures of 1700° and 1750°, however, the lower sulphur steel was fine-grained only with an aluminum addition of 1 1/2 lb, per ton;

Jan 1, 1945

By A. J. Weinig

THE Liberty Bell cyanide precipitate is unique in that it is apt to vary widely in composition in the course of very short, periods of time, and a method of refining and melting that would prove highly satisfactory at one cleanup would yield almost an hopeless "mess" it a second. Table I gives a general conception of the wide range in grade and composition of those raw precipitates. It is evident that no one standard flux could be expected to produce a high-grade bullion with such a widely variable precipitate, and that any method of treatment with acid requires most careful consideration. Refining by Acids Naturally, our first efforts to improve our precipitates were directed along the lines of acid treatment. Table II embodies the results of careful sampling and analysis of one cleanup at the time when wet refining reached its maximum development at this mill. We have now discarded all methods of wet refining, successfully replacing them by amore scientific method of flux calculation described herein, but it is believed that a general description of this wet refining is warranted as it throws some interesting side lights on acid refining in general.

Jan 3, 1916

By Roswell P. Angier, Herbert S. Kalish, Henry H. Hausner

POWDER metallurgical methods as applied to zirconium are of great interest because they permit not only the fabrication of parts directly to shape with a minimum loss of material but also the utilization of scrap, and the metal may be processed at temperatures well below the melting point. There are two difficulties involved in the melting of zirconium: 1—High vacuum is necessary for melting, and 2—zirconium reduces nearly all oxides so that it is difficult to find a suitable crucible material. The purest material, zirconium crystal bar, is expensive, and the methods of subsequent fabrication are limited. Cold rolling or extrusion of zirconium crystal bar is suitable for making certain shaped parts, but where melting is involved, the purity of the metal is invariably decreased, and a method of casting to a definite shape does not seem to be feasible. Where it is necessary to hot roll, zirconium must be covered with a steel or copper jacket to protect it from the air. This is necessarily a costly operation. Where annealing of zirconium is necessary it must be conducted in a high vacuum. In an investigation of powder metallurgical methods for zirconium, the zirconium powder used should be characterized by the following properties: 1— Highest degree of purity, 2—uniformity in particle shape and particle size distribution, 3—low compression ratio, and 4—satisfactory strength of the compacted powder (green strength). Zirconium powders have been made by two methods: By the reduction of zirconium tetrachloride (ZrC1,) with sodium,2' *•B "nd by the reduction of zirconium oxide with calcium and calcium chloride." The first method represents one of the earliest attempts to make pure zirconium metal, and the sintered product from this powder is extremely brittle. The second method of making zirconium powder is far more successful, but the powder made in this way has an extremely low apparent density and, therefore, a high compression ratio which makes it difficult to use it for powder metallurgical purposes. For these reasons the above-mentioned zirconium powders were not used in this investigation. To obtain sintered zirconium compacts of highest 'purity and good ductility, it was first necessary to produce a suitable powder. Pure zirconium has been made chiefly by two methods. The iodide method, from which the product is "crystal bar" zirconium, was developed first.'." By this purification process very soft, pure, and ductile zirconium metal can be produced. The second method, developed by the U. S. Bureau of Mines, is the reduction of zirconium chloride with magnesium." The sponge zirconium thus produced is also soft, pure, and ductile.

Jan 1, 1952

By C. M. Myrick

(Cleveland Meeting, October, 1912) THE following notes are submitted in the belief that they may interest some of the many owners of small water-power plants, so generally used in mining-work throughout the West. A small and somewhat primitive quartz-mill was taken over by a leasing company, and a 10-stamp battery was installed. Originally, power had been furnished by a Pelton wheel ; but, since the supply of water depended on the rate at which snow was melting on the mountains, a steam-plant had been added to help out during cold spells. This auxiliary plant was antiquated and expensive to operate, and, soon after starting up the remodeled mill, it broke down completely; so that it became necessary to get all the power possible out of the Pelton wheel,. with its ever-varying water-supply. The pipe-line, about a quarter of a mile long, was made up. of assorted sizes, from 7 to 11 in. in diameter; and, since it was buried deep under snow, there were no data from which to calculate the theoretical size of the nozzle. The stream being at this time at a low stage, it was important to make the most efficient use of the available water. This was done by using a nozzle large enough to pass the whole supply-taking care, however, to limit the size so as not to lower the water-level in the tank at the head of the pipe-line. As the weather became warmer, the nozzles were gradually enlarged to meet the increasing volume of water; but a point was finally reached where further enlargement only gave decreased power. Evidently the loss from friction had more than balanced the gain from the increased flow through the pipe. However, the area of nozzle that developed the, maximum power from the pipe-line had been found. This was used; and the surplus water was allowed to run to waste at the head of the line.

Oct 1, 1912

By F. R. Hensel

The present study was made to determine the laws governing the formation of the primary? crystal structure during solidification. Most of the experiments were carried out on chill castings, but from the resiilts it will be possible to draw certain conclusions as far as sand castings are concerned. It is necessary to discuss first a number of theories, which are generally adopted for explaining the structure of an ingot. Usually, the structure of an ingot consists of the following three zones (Fig. 1): (1) a chill layer of small at-random oriented crystals; (2) a layer of columnar crystals; (3) a zone of equiaxed crystals. The tensile properties of the chill layer and the equiaxed range are usually much better than in the columnar range, particularly the planes that are formed by the columnar crystals growing from two sides at right angles have low tensile properties. This is one of the reasons why columnar crystals in ingot structures are undesirable.

Jan 1, 1937

By A. Perry Thompson

Discussion of the paper of A. PERRY THOMPSON, presented at the San Francisco meeting, September, 1915, and printed 'in Bulletin No. 100, April, 1915, pp. 645 to 677. ARTHUR S. EAKLE, Berkeley, Cal.-At the old Morning Star mine in Alpine County, where large masses of enargite were found some years ago, I looked particularly for evidences of replacement of pyrite by the enargite. While I have not made a particular study of any of the specimens, I judge that the pyrite and enargite were precipitated together. They were both primarily in those rocks. Of course, by using Mr. Graton's method of determination we might possibly find a situation somewhat different, but I should say that the enargite is not replacing the pyrite, but was simply precipitated at the same time. The bodies occurred there within 50 ft. of the surface, so it is probably not a case of secondary enrichment. H. W. TURNER, San Francisco, Cal.-In the case where secondary chalcocite shows a crystalline structure and cleavage lines, what is the evidence of the secondary nature of it? C. F. TOLMAN, Stanford University, Cal.-You can find practically all the evidences we have discovered in the microscopic study of ores. You can find all stages in the process of replacement of earlier minerals, especially bornite, by chalcocite, from a stage, in which the process has but just started with only occasional fragments of chalcocite set in bornite, to a stage where remnants of bornite are set in chalcocite. The replacement may take place along the cleavage lines or along the crystallographic directions of the earlier mineral, or it may take place irregularly. In one type of replacement you may find in one spot a few cross-cutting veins, and in another spot the latter may be so enlarged that there remain only a few individual specks of the replaced mineral.

Jan 12, 1915

By J. Nolan, B. Ande’n, E. Lindgren

Field testing was conducted at the Strassa Iron Ore Processing Plant to evaluate high-gradient magnetic recovery of iron from the plant's tailings. The installation is the first commercial application of the Sala Continuous High-Gradient Magnetic Separator (HGMS) Model 480 Carousel. The objectives of the five-month testing program included optimization of the operating parameters using SSDEVOP techniques to maximize iron recovery, along with establishing a long-term operating history for the SALA 480 HGMS Carousel. The effectiveness of the optimization procedure, the net benefit in term of iron recovery, and equipment performance are discussed in the paper.

Jan 1, 1983

By W. C. Hauber

Techniques previously published to predict the production performance of a water flood when the mobility ratio is not unity have been primarily restricted to a five-spot well pattern. When other types of well patterns are considered, the prediction of performance has required either a model study or a complex numerical solution of a multiple-fluid system with a high-speed digital computer. Simple methods are developed in this report for predicting the areal sweep efficiency and injectivity history of a water flood for arbitrary well patterns and mobility ratios. The effect of an initial gas saturation can be incorporated into this method of prediction. With the layer superposition concepts published by Prats, et al.,1 these methods can be used to predict the production performance of a water flood in a reservoir having a wide range in permeability. A reasonably good agreement is shown by comparisons of the results calculated by this method with those obtained either by model studies or by complex numerical solution of multiple-fluid systems. Therefore, it has been concluded that a reasonably accurate method has been developed for predicting the production performance of a water flood employing an arbitrary type of well pattern for any given mobility ratio. A medium-speed digital computer can be used in applying this method. INTRODUCTION Production performance of multi-fluid five-spot water floods can be predicted by the techniques published by Prats, et al.1 This technique takes into account the effects of initial gas saturation, mobility ratio and vertical variations in horizontal permeability. A basic assumption in applying this technique is that unit displacement efficiency does not vary with time after the passage of the flood front. Prats, et al. demonstrated that this assumption is valid for normal waterflood applications with small mobility ratios. To extend Prats' technique to other types of well patterns has required either an experimental model study or a numerical solution of a multiple-fluid system to describe the performance of an individual homogeneous layer. Sheldon and Dougherty2 presented an exact numerical solution employing any arbitrary well pattern. This technique is complex to apply, requiring (1) numerical solution of the single-fluid system, (2) conformal mapping of the streamlines and iso-potential lines to form a new grid network, and (3) a numerical solution of the multi-fluid system on the new grid network. A method was developed in this paper to approximate areal sweep efficiency and injectivity as functions of time for an individual homogeneous layer for arbitrary well patterns and mobility ratios. Analytic expressions were derived to directly apply this method to five-spot and direct line drive well patterns. For other types of well patterns, this method is similar to the approach of Higgids and Leighton,6 in that it utilizes the stream tubes and iso-potential lines obtained by the solution of differential equations when the mobility ratio is unity. However, this method is easier to apply than the Higgins-Leighton method since it does not require knowledge of the variation between oil and water relative permeabilities and saturation. Using the relationship between areal sweep efficiency, injectivity and the volume of water injected into an individual homogeneous layer as obtained by the method presented in this paper, and Prats' technique for the superposition of individual layers, one can predict the production performance of any water flood. ASSUMPTIONS GENERAL Basic assumptions made in this report are that fluids are incompressible and the layers are horizontal, homogeneous and uniformly thick. It is assumed that as water is injected into the layer, three distinct regions are formed —a water bank, an oil bank, and an unflooded region. Each region is assumed to displace other regions in a pis-tonlike manner, with only one fluid flowing in each region, so that there is no change in unit displacement efficiency with time after the flood front has passed in the reservoir. Therefore, the residual oil saturation in the water bank and the oil saturations in the unflooded region are constant throughout the layer. The ratio (F) of the bulk volume of a layer occupied by the oil and water banks at any time before oil breakthrough, to the corresponding bulk volume of a layer occupied by the water bank, is given' by the equation BREAKTHROUGH AREAL SWEEP EFFICIENCY To predict the behavior of any type of waterflood pattern, one must know the breakthrough areal sweep efficiency Eb(Mc,o, F) for the pattern for any water:oil mo-

Jan 1, 1965

By Eugene Coste

ALTHOUGH some of the observers who first paid especial attention to the occurrences of oil and gas in the strata (such as Hunt in 1859, Andrews in 1861, Winchell in 1865, Mendelejeff in 1876, Höfer in 1876, Minshall in 1881, and I. C. White in 1883) seem to have been impressed with the fact that oil and gas deposits were connected with the disturbances in the rocks caused by their upheaval,1 yet, with the exception of Mendelejeff, and possibly Andrews, these observers do not appear to have understood what is really the one essential factor in the occurrence of oil and gas in the strata: viz., the faulting, uplifting, fracturing, fissuring, and jointing always accompanying even slight rock disturbances, and in certain districts (petroliferous provinces)2 allowing solfataric hydrocarbon emanations to force their way up from the interior and to reach and impregnate the porous portions of sediments subjected to the disturbances. Instead of this simple explanation to account for the observed connection between petroleum deposits and rock disturbances, most of the observers mentioned above, and many others who have followed them on the name lines since, have entirely reversed the problem. To them, instead of the dissemination of gases from fissures into the sediments, it presented the accumulation and concentration, according to anticlinal or other geologic structures, of oil and gas originally present throughout the whole mass of the strata where they were produced by the decomposition or distillation of organic remains. Whether this important problem involves accumulation from sources within the oil-bearing strata themselves, or infiltration and dissemination from outside sources, may be easily determined if all preconceived ideas are put aside and the established facts only are considered.

Jan 9, 1914

By H. M. Callaway

There are key words common to Government and the minerals industry, the use of which immediately spark interest, argument and confusion. Among these is productivity, a term ranking for widespread misunderstanding with mineral self-sufficiency and mineral conservation. Each interpretation of these words tends to emphasize a single aspect and either minimize or ignore the complex dynamic system of things that influence the Nations mineral productiveness. This paper1, abstracted from a monograph on lead now being prepared for publication by the Bureau of Mines, not only sheds light on the trend of productivity in the lead-zinc mining industry but it presents the basis for forming a common general notion of what the term productivity implies.

Jan 11, 1961

By B. W. Frazier

IN the numbers of the Engineering and Mining Journal of June 27th and July 11th, 1874, there appeared some very complete statistics of the working of some anthracite blast-furnaces belonging to a large establishment in this country, followed by calculations of the heat requirements of the furnaces, similar to those which have been made for European furnaces by Mr. I. Lowthian Bell, Prof. Gruner, Prof. Akerman and others. To the author of these valuable papers, Mr. John A. Church, of New York, the thanks of American iron metallurgists are due for this attempt (the first, to my knowledge at least), to attack systematically and scientifically the problem of economy of fuel in our anthracite blast-furnaces, by applying the formulas obtained from European practice and from the experiments of European metallurgists, to the determination of the amounts and the modes of distribution of the heat production and absorption in our furnaces. In order to facilitate a comparison of the results thus obtained for the anthracite furnaces in question with those obtained for the best types of European coke furnaces, I have reduced to the same standard of heat units (the product of the ton and the degree Centigrade), and placed side by side, the calculations of the heat requirements of one of the furnaces of the Clarence works, as given by Mr. Bell, of a furnace at Pouzin, on the banks of the Rhone, given by Prof. Gruner, and of the anthracite furnaces for 1869-73, as given -by Mr. Church. Table I shows the different conditions of working of the three furnaces, of which Table II gives the respective heat requirements. I have made this latter table in such a manner as to give for each furnace its heat requirements, both according to the views of Mr. Bell and those of Prof. Gruner. Mr. Bell assumes that all the carbonic acid produced by the decomposition of the carbonate of lime of the charge, is reduced to carbonic oxide by contact with solid carbon ; also, that the carbon of the pig iron is a portion of that deposited in the ore in the upper part of the furnace, by the dissociation of carbonic oxide. Prof. Gruner, on the other hand, assumes that all the carbonic acid of the carbonates of the charge escapes unreduced, and that the carbon deposited in the upper part of the furnace, by the dissocia¬tion of carbonic oxide, is again converted into carbonic oxide or

Jan 1, 1875

By B. W. Frazer

In the numbers of the Engineering and Mining Journal of June 27th and July llth, 1874, there appeared some very complete statistics of the working of some anthracite blast-furnaces belonging to a large establishment in this country, followed by calculations of the heat requirements of the furnaces, similar to those which have been made for European furnaces by Mr. I. Lowthian Bell, Prof. Gruner, Prof. Akerman and others. To the author of these valuable papers, Mr. John A. Church, of New York, the thanks of American iron metallurgists are due for this attempt (the first, to my knowledge at least), to attack systematically and scientifically the problem of economy of fuel in our anthracite blast-furnaces, by applying the formulas obtained from European practice and from the experiments of European metallurgists, to the determination of the amounts and the modes of distribution of the heat production and absorption in our furnaces. In order to facilitate a comparison of the results thus obtained for the anthracite furnaces in question with those obtained for the best types of European coke furnaces, I have reduced 60 the same standad of heat units (the product of the ton and the degree Centigrade), and placed side by side, the calculations of the heat requirements of one of the furnaces of the Clarence works, as given by Mr. Bell, of a furnace at Pouzin, on the banks of the Rhone, given by Prof. Gruner, and of the anthracite furnaces for 1869-73, as given by Mr. Church. Table I shows the different conditions of working of the three furnaces, of which Table II gives the respective heat requirements. I have made this latter table in such a manner as to give for each furnace its heat requirements, both according to the views of Mr. Bell and those of Prof. Gruner. Mr. Bell assumes that all the carbonic acid produced by the decomposition of the carbonate of lime of the charge, is reduced to carbonic oxide by contact with solid carbon ; also, that the carbon of t,he pig iron is a portion of that deposited in the ore in the upper part of the furnace, by the dissociation of carbonic oxide. Prof. Gruner, on the other hand, assumes that all the carbonic acid of the carbonates of the charge escapes unreduced, and that the carbon deposited in the upper part. of the furnace, by the dissociation of carbonic oxide, is again converted into carbonic oxide or

By M. M. Mebta, G. W. Dean, W. H. Somerton

With the advent of underground heating operations, interest has developed in the alteration of rock properties by high-temperature treatment. In the present work a number of sandstones were heated to temperatures in the range of 400°C to 800°C under both atmospheric and simulated reservoir pressures. Pertneabilities increased by at least 50 per cent and sonic velocities and breaking strerlgths decreased by an equivalent amount. Differential thermal expansion and other reactions of constituent min-era1 grains are the causes of these alterations. INTRODUCTION In the underground combustion of petroleum reservoirs, temperatures of the order of 600C are reported to have been reached in the combustion zone.' At this temperature rocks are subject to extensive thermal alteration. Temperatures of this magnitude and higher may also occur in subsurface formations when subjected to bottom-hole heating, thermal drilling operations, and underground nuclear explosions. Temperatures of this magnitude might also be generated by conventional rock drilling methods at points of bit-tooth contact. In earlier work, the permanent deformation of rocks resulting from heating was reported. Major structural damage of rocks occurs due to differential thermal expansion of mineral constituents. A number of mineral alterations including crystal inversions, loss of water of crystallization and dissociation, may also contribute to changes in physical structure and properties of rock. In the present work, samples of three typical sandstones were heated to several temperatures up to a maximum of 800C and then allowed to cool to room temperature. Heating was done under both atmospheric pressure and simulated reservoir pressure conditions. Physical properties of the samples were measured before and after heating and comparisons made. Measured properties included permeability, sonic velocity, breaking strength and fracture index. Changes in physical properties were compared to changes in mineralogical characteristics as determined by thin-section. X-ray diffraction and chemical tests. EQUIPMENT AND PROCEDURE Two outcrop sandstones (Bandera and Berea) and one sub-surface sandstone (St. Peter) were selected for the tests. These samples have a wide ranee in composition and physical properties as shown in Table 1. The first series of tests was made on 2-in. diameter by 5-in. long test specimens. Test specimens used in all later work were 3/4-in. diameter by 1 1/8-in. long, this being the specimen size required for heating at simulated reservoir pressures. After careful washing, the cores were oven dried at 100 ± 5C for a minimum of 24 hours before the tests were run. Test specimens were heated in an electric furnace at a constant rate of temperature increase of 3C per minute. When maximum temperature of the run was reached, the sample was allowed to soak for one hour. The furnace was then cooled to room temperature at the same rate of 3C per minute. The entire heating operation was designed for reproducibility without subjecting the test specimens to excessive thermal shock. For samples heated under simulated reservoir pressures, a pressure cell designed by Dean was used (Fig. 1).3 The core sample was inserted into a thin-walled (0.006 to 0.01-in.) copper cup which was then mounted in a high-pressure cell. Provisions were made for the application of internal pore pressure as well as confining pressure. Tests showed that the thin-walled copper cup closed tightly around the core and satisfactorily transmitted confining pressure to the core. The core was heated by placing the entire cell into the electric furnace. The heating program was the same as that used in the atmospheric pressure runs: tempera-ture rise of 3C per minute to maximum temperature of the test, soaking at maximum temperature for one hour, and cooling at a rate of approximately 3C per minute. The cell was designed to withstand 5,000 psi at 1,000C. However, since it was considered likely that repeated heating and cooling would in time weaken the steel, 2,000 psi at 850C was set as a working limit. In the present series of tests, the pore pressure was held constant at 750 psi and the confining pressure at 1.500 psi. The pressure source was a high-pressure nitrogen tank. The two pressures were controlled manually but are accurate well within ± 50 psi.

Jan 1, 1966

By Robert Steinitz

SOFT iron parts for magnetic applications, particularly pole shoes, constitute a major portion of the ferrous products of powder metallurgy. The residual pores in pressed and sintered parts reduce values such as the magnetic permeability but service experience extended over a number [ ] of years has proven beyond doubt that in many instances the lower density of powder parts is not prohibitive to their use m replacement of machined magnetic parts The. magnetic requirements for pole shoes particularly the permeability, vary within wide limits, especially with the relative size of the air gap in the finished assembly. The overall permeability of an assembly, µ, is given by the formula [ ] where µm is the permeability of the core material, l the total length of the magnetic path, and a the length of the air gap. Fig 1 shows the variation of the overall permeability with the permeability of the core material, calculated according to Eq I for an air gap of 1 pct of the total length of the magnetic circuit. It is readily recognized that to use core materials hav-

Jan 1, 1948

By Milton E. Wadsworth

INTRODUCTION The purposes of this conference are aimed mainly at the treatment of fine or ultra fine particles in terms of beneficiation and chemical processing of minerals. For this reason the discussion on leaching will be confined to processes which treat slurries rather than those which treat a large variety of low and medium grade materials by vat leaching or dump leaching techniques. This eliminates such hydro-metallurgical systems as solution mining from consideration. This discussion will focus predominantly upon the behavior of fine particles as associated with their chemistry in leach reactors. Four major sub-headings may be pointed to as encompassing the major areas in which research and engineering design activity should be directed. These are: 1) generation of fine particles, 2) heterogeneous kinetics of leaching, 3) solution chemistry, 4) engineering design and control of flow reactors. Each of these topics will be addressed briefly in this presentation to illustrate current developments and future needs. GENERATION OF FINE PARTICLES As will be pointed out more quantitatively in the next section the generation of fine particles has great influence upon leaching systems inasmuch as in most cases the rate of leaching is related to the surface area of the particles involved. This is true for acid or base leaching of oxide minerals as well as a large variety of sulfides which have been considered in commercial processes and which have in the case of copper received increased attention during the past decade. Mean particle sizes of slurries vary broadly depending upon the type of grinding equipment being used. For example, in the agitation leaching of uranium ore the slurry typically consists of particles approx-

Jan 1, 1979

By L. C. Snider

During the past few years a number of large and highly productive oil fields have been discovered in the United States. The immediate oversupply which has resulted, together with the circumstances under which the new fields have been operated, has created exaggerated impressions of the importance and magnitude of these fields. Statements as to the many years during which individual fields could supply the entire demand of certain areas, as to the overwhelming effect of these fields on the industry, and as to their greater size compared with any of the older fields have become so common as to attract little attention. For example, East Texas is commonly considered as the "greatest oil field" and a review of the development of the field for 1931 is so headed in one of the leading trade journals.' East Texas is unquestionably a very great oil field. However, some students of the field have estimated its ultimate recovery at about one billion barrels, and the Bradford field discovered in 1875 is also estimated, by competent engineers, to have about a billion barrels still recoverable by water drive, in addition to more than 300,000,-000 bbl. it has already produced. If East Texas should produce the two or three billion barrels assigned to it by more optimistic estimators, it will, though considerably greater than Bradford, still fall far short of it in importance to the industry. A reasonable doubt also exists as to whether East Texas will exceed the Midway-Sunset field which has produced about 720,000,000 bbl. and still has important reserves. Again, in importance to the industry, Midway-Sunset has been greater than East Texas can ever be. Relative Importance of Oil Fields The principal purpose of this study is to compare, on the basis of their importance to the industry, a considerable number of the major fields which have been developed in the United States. Some remarks are also made as to the estimates of reserves in certain fields now in course of development, since the writer believes that the conditions under which these fields are operated lead to estimates of recoverable reserves which

Jan 1, 1933

By Robert H. Dickson

Limestone replacement and contact metamorphic orebodies are 80 irregular that sampling and estimating are far less. exact than in more regular types of deposits; both the mineralized masses and the lenses of ore within them are extremely irregular. So much development work is required to find the ore that the expense of blocking out great tonnages is prohibitive; furthermore, the rock near these orebodies is so heavy that drifts or raises cannot be kept open for many years without excessive repairs. As a result, few mines in limestone have more than three years supply of ore in sight. As most of the ore, is developed by stoping— not by drifting, raising, or drilling—estimates of ore developed do not indicate the total amount of ore that may be expected; they simply indicate the relative condition of the mines. But even if they are to do this, they must be made according to a fixed plan, intelligently carried out. The estimates of ore in the Calumet & Arizona Copper mines, Warren District, Ariz., have been of much value to those who plan the mining and development work. This paper describes the methods of sampling and estimating used in these mines. Sampling Samples are taken in various ways and depend on the condition of the working and the purpose for which the sample is to be used. Drifts, crosscuts, and raises are sampled by channels or by taking a grab off each mine car as it is filled. Stopes are usually sampled by drill holes or by taking a representative sample off each mine car; the latter, or chute, sample is by far the best sample. All workings are studied periodically by an engineer, who makes graphic and detail notes of the geologic structure, as shown in Fig. 1. The daily car tally and assay of each particular working is added to the same sheet opposite the material it represents. These sheets make a permanent record, showing the exact boundaries as well as the grade of ore in all workings.

Jan 1, 1925