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By Richard R. Bains

"When l hear - I normally remember 10 percent When I hear and see - I can remember 15 to 25 percent When I hear, see, and do - I usually remember up to 50 percent" While this is not a truism in relation to each and every individual; on the average, this is the case. If we use this as a premise in training operator and maintenance personnel, then it must be obvious that we can't rely on a mere presentation, even one which includes the needed classroom participation and/or hands on work, to do a thorough job and to make this personnel totally proficient - 100 percent proficient. We have to have some other device some other means to make this a continuing process, a process wherein the people can grow in knowledge while performing their normal duties. We have to feel that the words "normal duties" are the key to the whole program. If you would ask a crusher operator what his duty is, he might say "To run this crusher so that we produce 250 tons per hour of a minus 13mm (minus 1/2 ") product." A maintenance man could say "To fix the unit when there is a problem." Both of these answers are legitimate but, they are only a part of the total picture. In order for each of these individuals to do the best job, he must know not just the specifics about the machine he works with or on - he must know the interrelation of all the machinery in the crushing circuit - how the efficiency of each machine affects the others - why a minor problem on one piece of equipment can generate a major problem for another unit which follows it or precedes it. In short, you cannot separate machine operation and maintenance from the application of the equipment in the crushing circuit - and obtaining this knowledge must be a part of the normal duty of crushing plant personnel. As an example a crusher - any crusher - is designed to crush oversize material. It is not designed to accept feed which is already at or less than the required product size. If sized material goes to the crusher, increase wear results by using the crusher as a chute or the crushing chamber can be clogged up with the fines. This latter point is particularly true with cone crushers, especially in the third (Short Head) stage of crushing. When a Gyradisc is used (fourth stage crushing) it is even more critical that the product be removed before the material goes to the crusher. The crusher cannot control this - the screen ahead of the crusher does. The screen must be of adequate size and be functioning properly to allow the crusher to work at optimum. Screening is both an art and a science. Since there are so many variables which affect the output of the screen, it is always best to have a screen which is larger than the sizing calculations dictate. The screens are the most important elements in the circuit. Without screens, specification materials cannot be made and the size of the screen will ultimately aid or hinder your ability to get the most production possible out of the plant. There is a formula available from all screen manufacturers which is designed to calculate the proper screen size. It takes into consideration the

Jan 1, 1982

By E. S. Machlin, Morris Cohen

GRENINGER and Troiano' were the first to establish the fact that the habit planes of mar-tensitic products are usually planes of high indices. In steels containing 0.55 to 1.4 pct C, the habit plane indices are {225}A.* In steels with more than 1.5 pct C and in Fe-Ni alloys, the indices are {259In. The presence of both habits in certain alloy steels has been reported recently." Several investigators"-" have subsequently attempted to provide an understanding of these complex habit relations. Bowles'6 work is the most recent and the most successful. Like Greninger and Troiano, Bowles concluded that the transformation occurs in two steps, the first, a strain (or displacement) that is homogeneous throughout the volume of the martensitic plate, while the second is a strain that is homogeneous only within relatively small portions of the martensitic plate. The first strain yields the measured tilt of the specimen surface, but does not produce the final martensitic structure. This and the correct lattice orientations are achieved by the second strain. Bowles also reasoned that each strain could be described by the motion of a plane of no rotation and no distortion (hereinafter called the invariant plane) in a direction not necessarily contained in the plane.** In applying these considerations to steels with {225}a habits, Bowles found that the habit plane coincided with the invariant plane of the first strain, a result which signified that the atoms move along certain paths during the transformation. Whether this correlation results from the existence of some sort of a plate nucleus6 lying along the invariant plane of the first strain, or whether the invariant plane primarily defines the preferred directions of propagation of the first strain, will be discussed in a later section. There are two obstacles to the general acceptance of Bowles' treatment: 1—it has not been shown that elements of his double-strain analysis are unique, and 2—it is not known whether his treatment applies to transformations yielding the {2591A habit. Unless these two questions are resolved, the correlation between the habit and invariant planes in the {225}A systems might be regarded as coincidental. Experimental Procedure Using a 70 pct Fe-30 pct Ni alloy as an example of a {2591A habit system, preliminary attempts were made to obtain a double-strain solution based on a Nishiyamax** set of orientation relations and on a Greninger-Troianot set, adopting the stereographic technique described by Bowles" who used the Kurd-jumow-Sachstt set in connection with the {225}A habit. These attempts were unsuccessful because the method is essentially one of trial and error and requires either exceedingly good luck or a prior knowledge of the results being sought. Consequently it was decided to measure independently the strain associated with the formation of a martensitic plate as well as the habit-plane indices of the particular plate. By means of matrix algebra, the measured strain was applied to the austenite lattice, whose orientation with respect to the strain was determined, in order to ascertain whether the resultant structure would have the lattice of martensite. This was not found to be the case, and hence it was assumed that the measured strain was the first of two Bowles-type strains, characterized by the motion of an invariant plane. A solution of this displacement was obtained in terms of the invariant-plane indices and the direction of motion of the atoms. Then the second strain

Jan 1, 1952

By J. L. Carne

ORE control is a matter of planning and supervision based on a foreknowledge of the content and distribution of ore. The Inspiration orebody is predominately a copper-sulphide blanket, overlain by an oxidized zone of copper silicates, copper carbonates, and barren capping. Most of the ore is treated by leaching, and the optimum requirement of this method is the goal toward which the mining schedule is aimed. Both open-pit operations and underground mining are used. The problems of ore control at Inspiration are: I—maintenance of metallurgical balance, 2—conservation of oxide ore, and 3—mining out of the orebody at an average grade which parallels that of the reserve figure. Prior to the fall of 1926 all of the Inspiration division ores were treated by flotation, but the mixed ores of the Live Oak—Keystone section carried too large a proportion of copper in the form of chrysocolla for satisfactory flotation. For this type of mixed ore the leaching process now in use had been worked out, and the plant was put into operation in the fall of 1926. The process is known as the ferric sulphate leach, and the leaching solvents contain both ferric sulphate and free sulphuric acid. Sulphide copper in the form of chalcocite is leached by the ferric sulphate, and the oxidized copper minerals are dissolved by the sulphuric acid. From the beginning of operations to the present time the plant has treated some 67 thousand tons of ore having an average copper content of 1.142 pct, of which 0.605 pct has been in the form of oxidized copper minerals. The plant is currently being operated at the rate of 11,500 tons per day, 7 days per week. However, this tonnage is produced in 6 days of mine operation. The average current grade is approximately 1 pct copper, of which about 50 pct is present as oxidized or acid-soluble copper. Close control of metallurgical procedures is a vital factor in operation of the plant and is in turn dependent upon careful regulation of feed. An excess of sulphide copper requires the presence of more ferric sulphate in the leaching solvents. On the other hand, an excess of ferric sulphate in the presence of a low sulphide feed seriously reduces the efficiency of electrolytic precipitation in tank house operations. This condition must be avoided at all costs. An additional factor must be considered. It is known that the sulphide content is predominant in the ore which remains in the reserve. To maintain the necessary sulphide-oxide proportion, so that the entire reserve will mine out at both a grade and a sulphide-oxide ratio that will be permissible throughout the remaining life of the property, it is obvious that the oxide reserve must be currently preserved to as great an extent as possible. Fortunately much of the oxide reserve is found in the open-pit operation. This happy circumstance adds flexibility to the procedure and makes it possible to maintain the close regulation necessary to insure best overall results, both mining and metallurgical. The two ore streams from the pit and underground operations join at the coarse-crushing plant, and proper control must be exercised before the ore reaches this point. The open pit is currently providing about 55 pct of the ore and underground operations the balance of production. Both operations are under a single superintendent so that the closely interrelated problems may be more readily controlled. The least flexible of the two producing units is the underground mine, where the mining method is block caving. Although a block of ground may be undercut and developed, characteristics of the material determine its caving action. The ore in the chutes must be drawn. The area currently mined from underground is in a zone predominately sulphide and is generally

Jan 1, 1953

By J. L. Carne

ORE control is a matter of planning and supervision based on a foreknowledge of the content and distribution of ore. The Inspiration orebody is predominately a copper-sulphide blanket, overlain by an oxidized zone of copper silicates, copper carbonates, and barren capping. Most of the ore is treated by leaching, and the optimum requirement of this method is the goal toward which the mining schedule is aimed. Both open-pit operations and underground mining are used. The problems of ore control at Inspiration are: 1-maintenance of metallurgical balance, 2-conservation of oxide ore, and 3-mining out of the orebody at an average grade which parallels that of the reserve figure. Prior to the fall of 1926 all of the Inspiration division ores were treated by flotation, but the mixed ores of the Live Oak-Keystone section carried too large a proportion of copper in the form of chrysocolla for satisfactory flotation. For this type of mixed ore the leaching process now in use had been worked out, and the plant was put into operation in the fall of 1926. The process is known as the ferric sulphate leach, and the leaching solvents contain both ferric sulphate and free sulphuric acid. Sulphide copper in the form of chalcocite is leached by the ferric sulphate, and the oxidized copper minerals are dissolved by the sulphuric acid. From the beginning of operations to the present time the plant has treated some 67 thousand tons of ore having an average copper content of 1.142 pet, of which 0.605 pct has been in the form of oxidized copper minerals. The plant is currently being operated at the rate of 11,500 tons per day, 7 days per week. However, this tonnage is produced in 6 days of mine operation. The average current grade is approximately 1 pct copper, of which about 50 pct is present as oxidized or acid-soluble copper. Close control of metallurgical procedures is a vital factor in operation of the plant and is in turn dependent upon careful regulation of feed. An excess of sulphide copper requires the presence of more ferric sulphate in the leaching solvents. On the other hand, an excess of ferric sulphate in the presence of a low sulphide feed seriously reduces the efficiency of electrolytic precipitation in tank house operations. This condition must be avoided at all costs. An additional factor must be considered. It is known that the sulphide content is predominant in the ore which remains in the reserve. To maintain the necessary sulphide-oxide proportion, so that the entire reserve will mine out at both a grade and a sulphide-oxide ratio that will be permissible throughout the remaining life of the property, it is obvious that the oxide reserve must be currently preserved to as great an extent as possible. Fortunately much of the oxide reserve is found in the open-pit operation. This happy circumstance adds flexibility to the procedure and makes it possible to maintain the close regulation necessary to insure best overall results, both mining and metallurgical. The two ore streams from the pit and underground operations join at the coarse-crushing plant, and proper control must be exercised before the ore reaches this point. The open pit is currently providing about 55 pet of the ore and underground operations the balance of production. Both operations are under a single superintendent so that the closely interrelated problems may be more readily controlled. The least flexible of the two producing units is the underground mine, where the mining method is block caving. Although a block of ground may be undercut and developed, characteristics of the material determine its caving action. The ore in the chutes must be drawn. The area currently mined from underground is in a zone predominately sulphide and is generally

Jan 1, 1952

By J. L. Carne

ORE control is a matter of planning and supervision based on a foreknowledge of the content and distribution of ore. The Inspiration orebody is predominately a copper-sulphide blanket, overlain by an oxidized zone of copper silicates, copper carbonates, and barren capping. Most of the ore is treated by leaching, and the optimum requirement of this method is the goal toward which the mining schedule is aimed. Both open-pit operations and underground mining are used. The problems of ore control at Inspiration are: I—maintenance of metallurgical balance, 2—conservation of oxide ore, and 3—mining out of the orebody at an average grade which parallels that of the reserve figure. Prior to the fall of 1926 all of the Inspiration division ores were treated by flotation, but the mixed ores of the Live Oak—Keystone section carried too large a proportion of copper in the form of chrysocolla for satisfactory flotation. For this type of mixed ore the leaching process now in use had been worked out, and the plant was put into operation in the fall of 1926. The process is known as the ferric sulphate leach, and the leaching solvents contain both ferric sulphate and free sulphuric acid. Sulphide copper in the form of chalcocite is leached by the ferric sulphate, and the oxidized copper minerals are dissolved by the sulphuric acid. From the beginning of operations to the present time the plant has treated some 67 thousand tons of ore having an average copper content of 1.142 pct, of which 0.605 pct has been in the form of oxidized copper minerals. The plant is currently being operated at the rate of 11,500 tons per day, 7 days per week. However, this tonnage is produced in 6 days of mine operation. The average current grade is approximately 1 pct copper, of which about 50 pct is present as oxidized or acid-soluble copper. Close control of metallurgical procedures is a vital factor in operation of the plant and is in turn dependent upon careful regulation of feed. An excess of sulphide copper requires the presence of more ferric sulphate in the leaching solvents. On the other hand, an excess of ferric sulphate in the presence of a low sulphide feed seriously reduces the efficiency of electrolytic precipitation in tank house operations. This condition must be avoided at all costs. An additional factor must be considered. It is known that the sulphide content is predominant in the ore which remains in the reserve. To maintain the necessary sulphide-oxide proportion, so that the entire reserve will mine out at both a grade and a sulphide-oxide ratio that will be permissible throughout the remaining life of the property, it is obvious that the oxide reserve must be currently preserved to as great an extent as possible. Fortunately much of the oxide reserve is found in the open-pit operation. This happy circumstance adds flexibility to the procedure and makes it possible to maintain the close regulation necessary to insure best overall results, both mining and metallurgical. The two ore streams from the pit and underground operations join at the coarse-crushing plant, and proper control must be exercised before the ore reaches this point. The open pit is currently providing about 55 pct of the ore and underground operations the balance of production. Both operations are under a single superintendent so that the closely interrelated problems may be more readily controlled. The least flexible of the two producing units is the underground mine, where the mining method is block caving. Although a block of ground may be undercut and developed, characteristics of the material determine its caving action. The ore in the chutes must be drawn. The area currently mined from underground is in a zone predominately sulphide and is generally

Jan 1, 1953

By Edward Keller

(Canal Zone Meeting, November, 1910.) UNDER the title, Labor-Saving Appliances in the Works-Laboratory, I published a paper1 in which was described how multi-manipulations, in a works-laboratory, and in the furnace-room of an assay-laboratory, can be condensed into single manipulations by applying the proper mechanical devices. For example, I now deposit in, or withdraw from, a muffle a set of 48 cupels as one unit. The front row. (8) of these. are blanks or heaters; the other 40, when they have attained the proper temperature in the muffle, are charged simultaneously with the 40 lead-buttons. Three manipulations here accomplish an operation which by the generally customary method requires 136, and this number is only limited by the size of muffle and cupels. This operation is an enlargement of what I have already described in my former paper, and Fig. I shows the improved implements. In the paper referred to I described a gold-silver bead parting-bath, which is the last of the devices used in regular sequence in practice. This bath was designated as being convenient, but was not a labor-saver properly. Fig. 2 of the present paper shows a new device. Instead of the original tray, there are now sectional holders for the test-tubes, each having a wooden handle on either end, so that the holders may be removed from the boiling bath, and the acid or water poured off from each set of tubes (in this case, 7) without waiting to cool. The tubes, held in place by clutches, as shown in Fig. 3, rest in holes in the base-strip, having a smaller diameter than the tubes. Each holder is stamped at either end with a number, so that the bath becomes further useful by permitting several men to use it at the same time without interference. Apart from the handles, the holders are made of sheet-copper. ' Trans., xxxvi., 3 to 18 (1906).

Aug 1, 1910

By A. W. Gauger

It is with some trepidation that I approach my subject, for I know that I shall at once incur the suspicion of the mechanical engineer, with his concern for boiler tests and efficiencies; of the mining engineer, with his mechanization problems; and of the chemical engineer with his unit processes. Nevertheless, it must be recognized that the technology of fuels, the systematic body of knowledge relating to the production, processing and utilization of mineral fuels, has grown to such proportions and involves so many widely diverse applications of fundamental science and engineering that it behooves us to stop and consider just what its status is in relation to other technologies, as well as in relation to the present and future needs of the social order. The time has come when technologists, applied scientists and engineers must consider the possible effects that their achievements may have on Society. The development of a machine to - -replace -several hundred men is a fine achievement when considered solely from the point of view of creative endeavor. But what of the men who are displaced by the machine! Does not the responsibility for the development of this machine embrace as well the consequences of obsolescence and technological unemployment resulting from such development? I believe that it does and that we must recognize this fact in our practice of engineering and tech- nology as well as in the training of future engineers and technologists. Magnitude of the Fuels Industry Fuel technology is the body of knowledge that relates to the mineral fuels. The fuels industry is by far the most important of all Our mineral industries. The chart in Fig. I, reprinted from U. S. Bureau of Mines Information Circular No. 6643, indicates the compartive values of metals, fuels and other nonmetallic minerals for the year 1929. Of the grand total of 13¼ billions of dollars in value of minerals at the mines, the mineral fuels contributed 48 per cent. Coal, with 34.4 Per cent, exceeded the value of any other single mineral. In fact, the value of the production of the Pennsylvania anthracite mines alone anand exceeds the value of the gold production of the entire world. Petroleum and natural gas in 1929 contributed 14.3 per cent and 3.3 per cent, respectively, of the total value of world mineral production. So much for the world picture; let us now look at the situation in the United States. Over the 60-year period 1880 to '939, $46,409,727,000 of metal1ic products, $80,788,852,000 of fuels (coal, petroleum, natural gas, natural gasoline) and $27,871,-ooo,ooo of nonmetallic minerals other than fuels were produced. The mineral fuels have contributed 52.7 per cent of the entire mineral wealth produced over this period that has seen such tremendous industrial development in our Our As a matter of fact, our present industrial civilization has been made possible through the use of the

Jan 1, 1942

By A. W. Gauger

It is with some trepidation that I approach my subject, for I know that I shall at once incur the suspicion of the mechanical engineer, with his concern for boiler tests and efficiencies; of the mining engineer, with his mechanization problems; and of the chemical engineer with his unit processes. Nevertheless, it must be recognized that the technology of fuels, the systematic body of knowledge relating to the production, processing and utilization of mineral fuels, has grown to such proportions and involves so many widely diverse applications of fundamental science and engineering that it behooves us to stop and consider just what its status is in relation to other technologies, as well as in relation to the present and future needs of the social order. The time has come when technologists, applied scientists and engineers must consider the possible effects that their achievements may have on Society. The development of a machine to - -replace -several hundred men is a fine achievement when considered solely from the point of view of creative endeavor. But what of the men who are displaced by the machine! Does not the responsibility for the development of this machine embrace as well the consequences of obsolescence and technological unemployment resulting from such development? I believe that it does and that we must recognize this fact in our practice of engineering and tech- nology as well as in the training of future engineers and technologists. Magnitude of the Fuels Industry Fuel technology is the body of knowledge that relates to the mineral fuels. The fuels industry is by far the most important of all Our mineral industries. The chart in Fig. I, reprinted from U. S. Bureau of Mines Information Circular No. 6643, indicates the compartive values of metals, fuels and other nonmetallic minerals for the year 1929. Of the grand total of 13¼ billions of dollars in value of minerals at the mines, the mineral fuels contributed 48 per cent. Coal, with 34.4 Per cent, exceeded the value of any other single mineral. In fact, the value of the production of the Pennsylvania anthracite mines alone anand exceeds the value of the gold production of the entire world. Petroleum and natural gas in 1929 contributed 14.3 per cent and 3.3 per cent, respectively, of the total value of world mineral production. So much for the world picture; let us now look at the situation in the United States. Over the 60-year period 1880 to '939, $46,409,727,000 of metal1ic products, $80,788,852,000 of fuels (coal, petroleum, natural gas, natural gasoline) and $27,871,-ooo,ooo of nonmetallic minerals other than fuels were produced. The mineral fuels have contributed 52.7 per cent of the entire mineral wealth produced over this period that has seen such tremendous industrial development in our Our As a matter of fact, our present industrial civilization has been made possible through the use of the

Jan 1, 1942

By R. R. Sayers

TWO serious hazards from coal dust confront the bituminous-coal miner- -a physical or safety hazard and a physiological or health hazard. The first threatens the miner with loss of life from coal-dint explosions, and the second with loss of health and earning capacity from inhaling large quantities of the dust. Studies by the Bureau of Mines have shown that coal dust, except some grades of anthracite dust, is capable of initiating an explosion when no explosive gas is present and that its property of extending or propagating an explosion has been responsible for nearly all the widespread explosions that have occurred in bituminous mines in the United States in the present century. For years many mining people believed that low-volatile coal dust was not explosive but not only is it explosive but if the source of ignition is intense, it is as explosive as the dust of many high-volatile coals because the war is creating increased pressure for greater coal production and because of the trend toward greater mechanization in mines, explosion and health hazards from coal dust are likely !n increase considerably.

Jan 1, 1943

By C. W. A. Newey

I would like to make the following points in connection with the studies of the deformation of NiAl reported in the recent paper by Wasilewski, Butler, and Hanlon. 1) Much of their paper is concerned with demonstrating that slip occurs on either {110)(001) or {100)(001) systems. In their discussion they state "the existence of (001) as the basic slip direction can thus be considered established." This fact was established by the earlier studies of Ball and Smallman.32 Ball and Smallman also concluded that the slip plane was of the type (110) and they showed that cross slip or pencil glide on orthogonal (110) planes could produce macroscopic slip on planes of the (001) zones, e.g., (100). Wasilewski et al. refer to this paper by Ball and Smallman but not in connection with the slip system determinations. 2) Wasilewski et a!. eliminate the possibility of (111) slip in NiAl on dubious grounds. Their statement that ('the very high yield strengths of the (100) oriented crystals", in which (001) slip is constrained, "immediately ruled out the possibility of {110)(111) slip" cannot be accepted unequivocably; it would be reasonable if the crystals were completely brittle but they are not, as Wasilewski et al. and others33734 have shown. Their elimination of the possibility of (111) slip in a crystal compressed along [227] is misleading since there is no obvious reason why (111) slip should occur in a crystal of this orientation. In fact, from an analysis of the macroscopic surface markings on deformed (100) stoichiometric crystals, Pascoe and Newey34 have deduced that slip occurs on systems of the type {211)(111) and {321)(111). 3) Polycrystalline NiAl is known to undergo general deformati~n.Having emphasized that general deformation is impossible if only (100) slip occurs, it is a pity that Wasilewski et al. do not attempt to account for the disagreement between theory and their experimental results. Of course, (111) slip can provide the additional independent systems required for general deformation.

Jan 1, 1969

By Arthur Notman

THE matters I had intended to present to you ap-peared in the March 12 issue of Engineering and Mining Journal over the signature of George J. Young, so that although I should like to talk to you for about three hours on this subject, unfortunately it has all been done before. The subject originally sug-gested to me was the trend in mining methods. You will find that fully set forth much more clearly than I could hope to do, in Mr. Young's article, so that I shall confine my attention to a few points of interest in specific cases. You are undoubtedly familiar with the problem that was presented to the Miami Copper Co. when they had exhausted their so-called high-grade orebody. They had what appeared to be a large tonnage of material which their preliminary development work and such drilling as was done indicated contained one per cent copper or a-little over, and how to mine that profitably by underground methods was the question. It was somewhat complicated by the fact that the nature of the ground made them doubtful of their ability to cave it successfully. It was unquestionably harder ground than that of the more highly mineralized sections of the Miami and Inspiration- ore zone which had been mined. However, they had kept very accurate and complete records of past accomplishments and knew what they had to work with and what modifications with respect to costs would be necessary in order to solve this problem. Under the old method of working, they were extract-ing about 71/2 tons per man employed in the mining department; that is to say all labor, direct and indirect required to put the ore in the mill bins, and this, with the grade of ore which they had, resulted in a satis-factory financial outcome. Under their modified method now in use, they have raised that output per man to 29 tons per man shift. That is almost four times what they were doing with the old method.

Jan 4, 1927

By A. Long, A. Silverman, J. L. Kulp

Garth Crosby has written an excellent geologic description of the deposits surrounding the Gem stocks in the Coeur d'Alene district. The ore deposits in the area of the Gem stocks may hold the key to the age and mineralization history of the entire Coeur d'Alene district. A recent isotopic study10 of the Coeur d'Alene district in this laboratory illustrates that a classical geologic interpretation of these deposits, with its implications for the whole district, may lead to erroneous conclusions. For this reason it seems pertinent to submit a summary of these results and an interpretation of the mineralizing history of the Coeur d'Alene districts. Pitchblende from the Sunshine mine has been dated as 1100-1200 million years (m.y.) by Kerr and Kulp,11 and Eckelmann and Kulp.12 This pitchblende is known to predate the major sulphide introduction in the Sunshine mine, but it clearly follows the metamorphism and folding of the Belt Series. Recently, Goldich (personal communication) dated sericite from the Belt rocks as 1200 m.y. by the potassium-argon method. This date establishes a minimum Belt age if the sericite is of metamorphic origin and a maximum age if detrital. The Belt Series, therefore, is not latest Precambrian. Lead isotope ratios of galenas have been measured and model ages calculated by Bate, et all3 for the Sunshine mine, Farquhar and Cummingl4 or the Bunker Hill and Sullivan mine, and Cannonl6,18 for a few other deposits in the district. Galenas from similar deposits in Southern British Columbia have been measured by Bate, et al,23 Farquhar and Gumming,11 and Wanless and Leech." The new work in this laboratory includes leads from ten widely scattered mines north and south of the Osburn fault, and through a vertical distance of over 5000 ft (Star mine). Included in this group are the Hercules, Sunset, and Mountain Goat mines, which are adjacent to the Gem stocks. In addition, galenas from stringers which cut the Gem stocks in the Success and Sunrise mines and the Hercules hanging wall dike in the lower western portion of the Hercules mine, were included in the study. All of the above leads, except one, give model ages of 1300-1400 m.y. for the time of segregation from the parent material. The concordance of the common lead and U-Pb ages, the great horizontal and vertical uniformity of the lead ratios, the sulphur ratios of two Sunshine mine galenas and three galenas from the Edith, Page, and Hercules mines indicating average crustal sulphur, and the U23/Pb204 ratio inferred for the original lead environment, indicate that the entire mineralization of the Coeur d'Alene-British Columbia base metal belt was derived from a deep source and emplaced in the Precambrian. One sample of galena from sulphide stringers cutting the North Gem stock at the Sunrise Prospect mine gave a modern (i.e., Tertiary) lead ratio. This mine is located at the northern tip of the stock. The presence of modern lead suggests mobilization of some rock lead during the intrusion of the Gem stocks and their outliers. Larsen et al.l8 have dated the Gem stocks as Tertiary by the lead alpha method. If Coeur d'Alene mineralization was genetically related to Tertiary magma formation and intrusion

Jan 1, 1961

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 Charles R. Cavanaugh, John F. Elliott

The activity of nickel in liquid Pb-iVi alloys which are rich in lead was measured in the temperature region of 700° to 1100°C by means of the galvanic cell: The electrolyte used was stabilized zirconia. Tlze data were correlated using the a function, and a plot of the temperature coefficient aE/aT All subsequent calculations of the thermodynamic properties are based on these two functions. The activity, activity coefficient, and molar properties of mixing of nickel are reported. Nicke1 shows extreme positive deviations frorn ideality while lead shows a very slight positive deviation in the composition range studied The study of the activity of nickel in liquid Pb-Ni alloys reported herein was undertaken to explore the use of stabilized zirconia, an oxygen-ion electrolyte, with liquid-metal electrodes, and to obtain further information on the thermodynamic properties of the liquid binary Pb-Ni system. The cell The reversible electromotive force of the cell results from the difference in the chemical potential of the oxygen at the two electrodes: po, (left) - p~ (right) = -4E5 [I] The chemical potential of oxygen on the right is fixed by the activity of nickel in the solution and pure solid nickel oxide. That on the left is set by pure solid nickel in equilibrium with pure solid NiO. By definition: Since the chemical potential of nickel is related to the chemical potential of oxygen through the equilibrium constant for the formation of NiO from nickel and oxygen gas, the electromotive force of the cell is also expressed In this case, n is 2, E is the reversible potential of the cell, and 5 is Faraday's constant. The work of Kuikkola and wagnerl and Schmalz-reid2 has shown that the stabilized zirconia electrolyte is essentially an ionic conductor at the oxygen levels encountered in the experimental arrangement of the work, i .e., PG > 10-l7 atm. THE EXPERIMENTS The advantage of this type of reversible cell over those using a liquid electrolyte is the simplicity arising because the electrolyte also functions as one of the containing crucibles. A further simplification was the choice of the Ni (sat.)-NiO electrode as the standard. This permitted a ready check on the behavior of the electrolyte, as the potential of the cell must become zero when the right electrode becomes saturated with nickel, either because of a change of temperature or because of the addition of nickel to the electrode. It also permitted the potentials being measured to lie in the most satisfactory experimental range of 0 to 100 mv. Although it was not theoretically necessary, lead was included in the standard electrode as it assured good contact between the electrode and electrolyte. Cell Design. The general arrangement of the experimental cell assembly is shown in Fig. l(a) and the details of the cell itself are contained in Fig. l(b). The anode lead wire on the interior of the cell was connected to a coil of perforated sheet nickel. Within this coil were nickel oxide pellets which were held beneath the surface of the liquid Pb-Ni alloy. A disc of nickel oxide was held at the bottom of the external crucible (alumina) by means of the thermocouple protection tube. The nickel oxide disc and pellets were compressed dry at 10,000 psi and sintered at approximately 1000°C for an hour in air. A major experimental difficulty of reversible electromotive force cells with liquid electrodes is the selection of suitable materials for connecting

Jan 1, 1964

The question, Who won the war?, has been the text for innumerable newspaper, and magazine articles, the answers running from "bread and butter" to "poison gas," in a material sense, and from the "Y. M. C. A." to the "boys in the front lines," humanly speaking. Personally, I think the margin by which success was secured was so narrow that none of the complex, interdependent factors could have been .spared, and that, as Admiral Sampson said after the battle of Santiago: "There is glory, enough for all." But if any one human factor can be said to have been absolutely indispensable, I think all will agree that it was the engineer. The engineer, as a rule, is a modest fellow, so modest in fact and so averse to publicity of any kind that, referring to him as a class, he was hardly occupying the place he should in public estimation before the war. By way of illustration, in the early history of a mine in Bisbee, the chief owner was also the proprietor of a saloon and spent most of his time there. When asked why he did not pay more attention to the mine, lie replied: "Oh! I can hire a boy to look after that; it takes a man to run this bar." Comparisons of the position and pay of engineers with other occupations are sometimes made to show that the engineer is not getting all that he should, considering the time of preparation and the qualifications required. Perhaps at least a part of the cause may be his aloofness from many of the practical affairs of everyday life. Whether he won the war or not, the part played by the engineer has certainly placed him on a sort of pedestal in the public estimation at present and it is very desirable to keep him there and maintain the position he has made for himself.

Jan 9, 1919

By Marvin J. Udy

THREE GENERAL REASONS exist for applying metallic coatings to steel: to improve its appearance, to resist corrosion, and to resist wear and abrasion. Coating steel with other metals to improve the appearance and to resist corrosion is an old practice; coating for resistance to wear is one of the newer development's' that has become of importance with the development of chromium plating. Coating for improvement in appearance is practically confined to electroplating. Metals like copper, nickel, silver, chromium, cadmium, zinc and tin, because of their pleasing color, are used for this purpose. But these metals are never quite corrosion-proof, except cadmium and zinc, when applied directly to steel. Improvement in color or appearance must be permanent and therefore corrosion-resistant and tarnish-proof. For this reason, with the exception of cadmium, zinc and tin, the above metals are used in combination to obtain appearance and resistance to corrosion. Resistance to tarnish is dependent on the property of the particular metal. Chromium, being nontarnishable, has made it possible to obtain combination coatings of copper, nickel and chromium, copper and chromium, or nickel and chromium, which improve the appearance and also resist corrosion and tarnish. Such coatings find a wide field in decorative work particularly the copper-nickel-chromium combinations, and when properly applied are very satisfactory.

Jan 1, 1932

By Sam N. Dewitt, Albert S. Trube

This paper presents a discussion of the pressure maintenance operations which were begun in the New Hope Field. Franklin County. Texas. in 1944. The project has required the injection of extraneous waters at depths from 7.300 to 8.000 ft with intake well-head pressures up to 4.000 psi in three different reservoirs — the Bacon. Hill. and Pittsburg. Records of oil and water production. water injection and the GOR have been kept for each reservoir and reservoir pressures were taken at regular intervals. These data indicate that the Bacon Reservoir had no apparent water encroachment up to the time of water injection. However. the Pittsburg and Hill reservoirs had some natural water influx hut not sufficient to prevent pressures from declining below the bubble point. The Bacon and Hill reservoirs responded almost immediately to water injection. while the Pittsburg which is the least permeable. has shown good pressure response only since .August, 1948. The principle objective of the project has been to increase ultimate recovery. Success of the project to date also has resulted in reduced lifting costs. Esti- mates based on the initial water breakthrough patterns indicate that the primary objective of substantial additional recovery will he accomplished, and there is a possibility that the original estimates elf oil recovery with pres-sure maintenance will he exceeded. INTRODUCTION This pressure maintenance project was one of the earliest primary pressure maintenance programs to he attempted on a multiple zone field. There are three producing reservoirs into which water is being injected for the purpose of maintaining pressure and increasing the ultimate recovery- from each. This paper is limited in scope to al1 account of the development of the project. the pressure production relationship prior to the injection of water and the effect of water injection on the producing reservoirs. Also discussed are the nature of the injection system and the indicated results on initial water break-through in the Bacon Reservoir. FIELD CONDITIONS The New Hope Field, which is located about 12 miles northeast of Winusboro, Franklin County, Texas, is an elongated symmetrical anticline containing four known oil reservoirs. The reservoirs are of the Trinity group of the Comanchean or Lower Cretaceous period and are found in Table I. The oil productive portion of each reservoir is not present in all of the producing wells because their areas and positions vary with respect to one another. Fig. 1 shows the relative position of the four reservoirs and illusIrate? how some wells could penetrate all four, while others are restricted to three. two. or perhaps one. depending on structural location. The first three reservoirs contain undersaturated oil. The deepest. the Elledge, has a primary gas cap. Although this reservoir covers a considerable area of the field. it has a very thin section and a low order of permeability. Elledge producing wells have generally been characterized by an early increase in GOR, making it necessary to recomplete them in other reservoirs. (At present. one well is completed in the Elledge. which is still producing.) Because of the difficulties en-countered in producing oil from this reservoir. and the small quantity of oil actually present. future attempts at producing it will probably be on a salvage basis during the later life of the program. For this reason, the remainder of this report will be confined to a discussion of the Bacon, Hill and pius-burg reservoirs.

Jan 1, 1950

By Raymond Mancha

The purpose of an accurate underground pressure survey is to obtain a pressure gradient along the circuit or circuits under investigation. The pressure gradient shows the rate of pressure drop between various observation points along a circuit. This determines excessive resistance regions and the economic feasibility of correcting such conditions by cleaning airways, driving additional airways, or modifying existing airways. A pressure gradient is useful for predicting the effect on other parts of the circuit when adjusting the air regulation on any one split or when planning a field airshaft or slope or a new drift to the outcrop. A single-compartment airshaft often produces disappointing results because it relievcs only a part of the circuit instead of the over-all mine pressure. It is valuable to know how the circuit pressure drop is distributed. The underground pressure survey is used also to determine the friction coefficient for various types of airway. High precision work is required to establish these vital data for predicting the characteristics of mine pressure volume when projecting new mine developments. Methods Regardless of the type of instrument used to conduct a circuit pressure survey, the work should preferably be performed at a time when the mine is idle, in order to avoid air-flow disturbances from moving trips and cages or from the opening or closing of trap doors. Preferably the survey should be made when the barometer is comparatively steady, to restrict variation in the air specific weight at observation stations while the circuit is traversed. The two most commonly used instruments for underground pressure surveys are: (I) the altimeter; (2) the inclined manometer with hose extensions. The altimeter is sufficiently accurate for determining the underground pressure gradient and is preferable to the nianometer for such work because of greater flexibility and shorter time required for the traverse. With the altimeter it is possible to select more widely separated observation stations than is practical with the manometer, with its restricted hose extension lengths. The altimeter also permits easier travel along haulage roads between airway observation stations, avoiding badly obstructed airways. The inclined manometer is more reliable than the altimeter for establishing friction coefficients in mine airways. Manometer readings are unaffected by differences in elevations between stations, which require corrections to altimeter data. The manometer provides direct reading without temperature correction, which may or may not be true with the altimeter, depending upon the make of instrument used. The elimination of correction factors combined with the instantaneous, simultaneous and

Jan 1, 1947

By Raymond Mancha

The purpose of an accurate underground pressure survey is to obtain a pressure gradient along the circuit or circuits under investigation. The pressure gradient shows the rate of pressure drop between various observation points along a circuit. This determines excessive resistance regions and the economic feasibility of correcting such conditions by cleaning airways, driving additional airways, or modifying existing airways. A pressure gradient is useful for predicting the effect on other parts of the circuit when adjusting the air regulation on any one split or when planning a field airshaft or slope or a new drift to the outcrop. A single-compartment airshaft often produces disappointing results because it relievcs only a part of the circuit instead of the over-all mine pressure. It is valuable to know how the circuit pressure drop is distributed. The underground pressure survey is used also to determine the friction coefficient for various types of airway. High precision work is required to establish these vital data for predicting the characteristics of mine pressure volume when projecting new mine developments. Methods Regardless of the type of instrument used to conduct a circuit pressure survey, the work should preferably be performed at a time when the mine is idle, in order to avoid air-flow disturbances from moving trips and cages or from the opening or closing of trap doors. Preferably the survey should be made when the barometer is comparatively steady, to restrict variation in the air specific weight at observation stations while the circuit is traversed. The two most commonly used instruments for underground pressure surveys are: (I) the altimeter; (2) the inclined manometer with hose extensions. The altimeter is sufficiently accurate for determining the underground pressure gradient and is preferable to the nianometer for such work because of greater flexibility and shorter time required for the traverse. With the altimeter it is possible to select more widely separated observation stations than is practical with the manometer, with its restricted hose extension lengths. The altimeter also permits easier travel along haulage roads between airway observation stations, avoiding badly obstructed airways. The inclined manometer is more reliable than the altimeter for establishing friction coefficients in mine airways. Manometer readings are unaffected by differences in elevations between stations, which require corrections to altimeter data. The manometer provides direct reading without temperature correction, which may or may not be true with the altimeter, depending upon the make of instrument used. The elimination of correction factors combined with the instantaneous, simultaneous and

Jan 1, 1947

By A. Romero-Juarez

This paper is concerned with the effect of propping-agent concentration on flow capacity of a fracture in the case in which there is embedment of the propping agent. Previous published studies have shown definitely that there is a relationship between fracture flow capacity and prop ping-agent concentration, and it has been shown that the theoretical results are confirmed by laboratory experiments. The problem of directly finding sand concentration for maximum flow capacity of a sand-propped fracture is solved, and formulas and charts are given to obtain this concentration under various conditions of effective overburden pressure, medium sand-grain diameter and rock properties. It is shown that, for the same effective overburden pressure and the same rock characteristics, optimum sand concentration in pounds per gallon does not depend on medium sand diameter. For conditions met in bydraulic fracturing operations, it is found that sand concentration in grains per square inch for maximum flow capacity varies within a wide range of values; this indicates the convenience of using data of fracturing pressure and rock characteristics for calculating sand concentration in order to achieve the best results in fracture treatments. INTRODUCTION It has been pointed out in the published literature1 that one important factor controls the success of a hydraulic fracturing operation — the propping of the fracture. The main effect of the propping agent is to hold the fracture open by means of the reaction forces that oppose the pressure due to the overburden. It is assumed in this paper that the propping agent is sand, that the grains are spherical and uniform in size, and that this sand is distributed in a monolayer in the fracture. The existence of a sand concentration value for maximum fracture flow capacity has been recognized since the publication of one of the first studies on the subject.2 In the reference cited, flow capacity was assumed to be proportional to the cube of the fracture volume per square inch not filled by sand. The obtained experimental curves relating to flow capacity and sand concentration had the same appearance as the curves obtained with the afore-mentioned assumption. Recent work3 has shown that fracture permeability, in the case of a monolayer, can be calculated accurately by means of a modified Kozeny-Cacman equation; thus, it can be shown that fracture pqmeability is a function of free volume in the fracture and of the rock and sand wet surfaces. The flow capacity of a fracture is dependent on the permeability of the fracture and on the fracture width. If all excessive quantity of sand is present in the fracture, its width may be large but its permeability i:; low due to the greater flow resistance; too few grains of sand per square inch are present in the fracture, sand embedment in the rock is greater and the width becomes small enough to appreciably decrease the rate of flow. To determine optimum conditions of flow, therefore, it is necessary to know the dependence of fracture width on density or concentration of propping agent. This relation is given in a study4 in which the approach to embedment is similar to the one made in a penetration hardness test of metal. With the equacions presented by Darin and Huitt,3 the number of sand grains per square inch that results in maxirnum fracture capacity can be determined graphically by plotting fracture capacity vs sand concentration. Since the relationship between fracture capacity and sand concentration may be considered known, one is led to formulate the analytical problem of directly determining sand concentration for maximum fracture flow capacity, in order to study the effect of the various quantities that come into the process. The solution of this problem appears to be interesting both from the viewpoint of fluid mechanics and from the practical viewpoint of oil production in hydraulic fracturing treatments. EQUATION FOR FRACTURE FLOW CAPACITY It can be shown3 that the fracture flow capacity of a monolayer is given by the following expression,