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By G. A. Reinhardt

THE Youngstown Sheet & Tube Co. has produced a large tonnage of 0.35 to 0.45 carbon forging steel, the acceptance of which was based on the physical properties of test specimens obtained by forging the original 5 3/4 in. (14.5 cm.) square bloom to a ¾ in. (1.9 cm.) round. Annealed and tempered specimens were required. The test bars were annealed by heating from 900 ° to 950° C. and cooling slowly in mica. The test bars were tempered by heating to 825° to 875° C., quenching in water, and drawing to 515° to 535° C. Immediately after heat treatment, the test pieces were machined to a diameter of 0.534 in. (1.38 cm.) and tested. Very good physical properties were obtained and no difficulty was experienced in meeting the specifications called for. ULTIMATE STRENGTH, ELONGATION, LB. PER SQ. IN. PER CENT. IN 4 IN. NOT LESS THAN Annealed specimens 78,230 to 92,450 18 Tempered 120,000 to 149,350 9 After experience oil this material, production of slightly higher carbon forging steel was started. The method of testing this material required that test blooms be either normalized or annealed. The normalizing consisted in heating to 850° to 900° C. and cooling in still air; the annealing, in heating to 850° to 900° C. and cooling in the furnace or in mica. From the treated bloom, the test pieces were taken either by core drilling or by sawing from points midway between the edges and the intersection of the diagonals. The cores or blocks were turned to a standard 2-in. test piece with a diameter of 0.564 in. and tested without further treatment. The physical requirements of the test pieces were:

Jan 7, 1919

By R. W. Raymond

[NoTE.—-This paper was presented at the Pittsburgh meeting in a partially completed form, and I fully expected to obtain, before the period of its publication, both the data and the leisure required for its completion. The hygiene of collieries was to have been separately considered, and the sanitary conditions of various metallurgical industries connected with mining were to receive an extended discussion, while at the same time the points treated in the paper as prosented at Pittsburgh were to have more ample illustration from American and European sources. Delay in obtaining expected information, and the continuous pressure of professional work, have prevented hitherto the execution of this plan ; and I can now publish only a portion of what I had designed to contribute to the subject. In the meantime this portion, but slightly changed, has been included as a chapter on the Hygiene of Metal Mines in a work entitled Hygiene and Public Health,, edited by Dr. A. H. Buck, of New York. An excellent chapter on the Hygiene of Coal Mines, contributed to the same work by Mr. Henry C. Sheafer, of Pottsville, affords me an opportunity to supply one of the deficiencies above alluded to. Mr. Shearer's chapter contains much material in the way of explanations not required by professional readers; And be moreover devotes a considerable space to the explosive gases, falls of roof, and other causes of accidents to life or limb—a branch of the subject not belonging strictly to bygiene. I therefore make extracts only from his treatise.—R. W. R ] It is convenient to divide mines, with reference to this subject, into two classes, collieries and metal-mines. Subterranean quarries, rock-salt mines, etc., present no conditions requiring them to be separated from the latter class.

Jan 1, 1880

By R. W. Raymond

[NOTE.-This paper was presented at the Pittsburgh meeting in a partially completed form, and I fully expected to obtain, before the period of its publication, both the data and the leisure required for its completion. The hygiene of collieries was to have been separately considered, and the sanitary conditions of various metallurgical industries connected with mining were to receive an extended discussion, while at the same time the points treated in the paper as presented at Pittsburgh were to have more ample illustration from American and European sources. Delay in obtaining expected information, and the continuous pressure of professional work, have prevented hitherto the execution of this plan ; and I can now publish only a portion of what I had designed to contribute to the subject. In the meantime this portion, but slightly changed, has been included as a chapter on the Hygiene of Metal Mines in a work entitled Hygiene and Public Health, edited by Dr. A. H. Buck, of New York. An excellent chapter on the Hygiene of Coal Mines, contributed to the same work by Mr. Henry C. Sheafer, of Pottsville, affords me an opportunity to supply one of the deficiencies above alluded to. Mr. Sheafer's chapter contains much material in the way of explanations not required by professional readers; and he moreover devotes a considerable space to the explosive gases, falls of roof, and other causes of accidents to life or limb-a branch of the subject not belonging strictly to hygiene. I therefore make extracts only from his treatise.-R. W. R] IT is convenient to divide mines, with reference to this subject, into two classes, collieries and metal-mines. Subterranean quarries, rock-salt mines, etc., present no conditions requiring them to be separated from the latter class.

Jan 1, 1880

By A. P. Boller

In the victories of peace as well as of war, the science of engineering has played a prominent, if, indeed, not the leading part. While it might be interesting, and food for profitable thought, to trace the development of engineering from early times in its bearings upon the social betterment of mankind, it will be sufficient on the present occasion to suggest a few thoughts that it is hoped will aid the unprofessional listener to an appreciative consideration of the subject-matter laid down for to-day's discussion, and possibly lead the professional brother to a higher conception of the profession to which he belongs. Since the advent of the railway era, it is difficult to grasp the sequence of historic events that have led to the wondrous derelopment of mechanical science, making possible the civilization that is our daily boast, and opening up a vista of future intellectual and moral advancement among the nations of the earth, 'before which the imagination becomes hopelessly lost. Even now, looking back over a period of only half a century, we often fail to realize the vast change in the relations of individuals and nations to each other., brought about by the results of those mechanical discoveries which, having made the whole world kin, exercise a resistless levelling influence that bears fruit politically in the spread of republican ideas, and morally in the elevation of the individual through the facilities given to the dissemination of Christian ideas and general intelligence. In this view, it seems almost like a work of supererogation for a body of representative men of one department of that science to which the whole world owe. so much, to meet here at the centre of our national life to plead not only for a practical recognition of the national importance of the work to which their lives are devoted, but also for national aid, on a scale beyond that of private effort, to the end that mechanical science may be carried to a higher plane than ever yet attained, each step on the way being of material benefit to every man, woman, and child in the community. Possibly this is strong language, but none too strong when we consider that the work for which we plead is one affecting not only vast scientific and commercial interests, but also human life, to a degree little ap

Jan 1, 1882

By F. G. Tickell, R. C. McCurdy, O. E. Mechem

The behavior of fluids in the voids of a rock is fundamental to the study of many of the problems of oil-field development and production. For it is by virtue of these openings between grains that oil and gas are able to move through the rock, to be contained by the rock, and to pass from the rock into the well. The capacity to contain fluids is measured by the porosity of the rock, and the ease of fluid movement is governed by the permeability. When the engineer wishes to estimate the amounts of oil and gas in an underground reservoir he is often concerned with the porosities of the rocks and, when dealing with problems relating to rate of production, he is more likely to be interested in the permeabilities of the rocks. Rocks are permeable because they are porous, but they may be porous without being permeable. Clays are very porous, and yet they are impermeable from a practical standpoint. Attempts have been made1 to correlate permeability with porosity for certain rock members but, where a definite relationship between these two properties is found to hold, it is purely fortuitous and local. Porosity and permeability do not necessarily bear any quantitative relationship to one another. The porosity of a substance is the percentage of void volume to bulk volume. The petroleum engineer is usually interested only in the inter-granular voids that are accessible to fluids. In measuring porosity he does not wish to include scaled openings. The measurement he desires is one of "available porosity," otherwise called "apparent porosity." The porosity of a natural aggregate of solid grains, such as a sandstone or clay, is governed by: (1) Grain-size distribution, (2) angularity of grain, (3) colloidal content, (4) degree of compaction. It is not difficult, for unconsolidated rocks, to measure the effect of any one of these when it alone is varied, and then to predict what the effects on porosity will be for such single variables. It is very difficult, however, if not

Jan 1, 1933

During the year Jan. 1 to Dec. 31, 1916, 962 applications for member-ship in the Institute were received, as compared to 558 during the corresponding period in 1915. The lines along which the Committee has, worked during the year, group themselves under seven principal heads. Large Companies.-Early in the year a letter was addressed to each member of the Institute who is the executive head of an organization, pointing out to him the advantages that would accrue to that organization through having as many of its subordinate members as were qualified participating in the activities of the Institute. This was followed by a second letter to those who made no reply to the first. The response to these letters was very gratifying, 12 new members having been secured at a single plant, and smaller numbers at others. This was effectively supplemented by our President, who wrote the executive heads of some of the largest mining and smelting companies, pointing out to them the advantage to be derived from sending some of the junior members of their staff to attend the Arizona Meeting. One organization sent 24 of its younger men, many of whom were not members of the Institute, but who, subsequently sent in applications for membership. It is to be hoped that the precedent thus set' will be acted 'on in -fuller measure in succeeding years.

Jan 2, 1917

The Year Book of the Institute is mailed with this Bulletin. Its membership lists, both alphabetic and geographic, are corrected to Jan. 1, 1918, but its list of officers is revised inn accordance with the elections in February, 1918. The amendment to the Constitution, relating, to qualifications for membership, adopted at the same time, is also inserted in its proper place. We would call attention to the Honor Roll, heading the list of membership. This includes the names of those whom we know (in February, 1918) to be on active military duty, as well as those who are rendering emergency service to the Government in other branches. We are aware that the list is not complete, and shall be grateful for information as to any omissions or corrections. Because of the rapid movement of the military members, their addresses have been omitted from the alphabetic list. Mail addressed to such members, and sent to the office of the Institute, will be forwarded to the best of our information at the time.

Jan 3, 1918

CAMBRIDGE, MASS., May 22, 1913. TO THE PRESIDENT, American Institute of Mining Engineers. Dear Sir: Referring to Mr. J. WV. Finch's letter printed in the Institute Forum of the May Bulletin, I am very much in sympathy with his suggestion that the Transactions be printed in several volumes devoted separately to the various subjects covered by the Institute papers, such as " Iron and Steel," "Mining Geology," " Precious and Base Metals," etc. The advantages of this plan appear to me so great and so obvious as to far outweigh any possible objections. At a meeting of the Iron and Steel Division Committee held on June 28, 1912, I moved that the Committee recommend to the Council that papers on Iron and Steel be published in separate annual volumes. The motion was seconded and passed. Since then I have never failed to repeat my request whenever an occasion presented itself, and I welcome the opportunity offered by Mr. Finch's communication to again call the attention of those interested to an innovation which appears to me so highly desirable. ALBERT SAUVEUR.

Jan 6, 1913

By C. M. Wayman, M. Miyagi

COMPARED to many of the binary alloys of iron, Fe-Ir alloys have received very little tud.'' Virtually nothing is known about the Fe-Ir equilibrium diagram' except for a few details concerning the liquidus-solidus positions for dilute iron-based alloys. It is reported1 that the y to a transformation temperature in Fe-Ir alloys (up to 40 wt pct Ir) is composition-dependent, varying from -900°C for pure iron to 0" to 100°C for Fe-40 pct Ir in an almost linear manner. The y to a transformation appears to be reversible,' the transformation hysteresis width increasing with increasing iridium content. In a qualitative way, the composition dependence of the y to a (and vice versa) transformations appears similar to those in the widely studied Fe-Ni system. In that the y phase (in Fe-40 pct Ir) can transform at -1000C, it

Jan 1, 1967

By G. A. Reinhardt, H. J. Cutler

ThE Youngstown Sheet & Tube Co. has produced a large tonnage of 0.35 to 0.45 carbon forging steel, the acceptance of which was based on the physical properties of test specimens obtained by forging the original 5 3/4-in. (14.5 cm.) square bloom to a 3/4-in. (1.9 cm.) round. Annealed and tempered specimens were required. The test bars were annealed by heating from 900" to 950' C. and cooling slowly in mica. The test bars were tempered by heating to 825' to 875" C., quenching in water, and drawing to 515" to 535" C. Immediately after heat treatment, the test pieces were machined to a diameter of 0.534 in. (1.38 cm.) and tested. Very good physical properties were obtained and no difficulty was experienced in meeting the specifications called for. UlTimate Strength.. Elongation, Lb. pER Sq. In. PEE Cent.. in 4 In. Not LeEs Than Annealed specimens.............. 78,230 to 92,450. 18 Tempered...................... 120,000 to 149,350 9 After experience on this material, production of slightly higher carbon forging steel was started. The method of testing this material required that test blooms be either normalized or annealed. The normalizing consisted in heating to 850" to 900" C. and cooling in still air; the annealing, in heating to 850" to 900" C. and cooling in the furnace or in mica. From the treated bloom, the test pieces were taken either by core drilling or by sawing from points midway between the edges and the intersection of the diagonals. The cores or blocks were turned to a standard 2-in. test piece with a diameter of 0.564 in. and tested without further treatment. The physical requirements of the test pieces were: yield point, pounds per square inch minimum, 44,800; ultimate strength, pounds per square inch, 89,600 to 112,000; elongation, per cent. in 2 in. not less than 17. Difficulty was encountered as soon as work on this material was started. Many precautions and refinements were instituted but it was found very difficult to secure the required elongation.

Jan 1, 1920

By James O. Lewis

Gravity drainage is the self-propulsion of oil downward in the reservoir rock. Under favorable natural and operational conditions, it has been found to effect recoveries comparable to water displacement. With modern technical knowledge, the operator can often make a choice between dissolved gas drive, water drive and gravity drainage as the principal recovery agent in a reservoir. It is desirable that the opeator be able to determine which of the three agents will be most effective under each set of conditions. So far, gravity drainage has received less consideration than the other two. In this paper. an endeavor is made to set forth some of the principles of gravity drainage, to point out the types of reservoirs favorable for it, and to show how it may be applied in them. Field examples are described and discussed. Introduction Since early in the history of the oil industry, it has been recognized that gravity is one of the three important natural forces for expelling oil from the reservoir rock. As knowledge of the technology of oil recovery progressed, ideas changed with respect to the relative importance of the three forces and with respect to the manners in which they functioned. For a time, disproportionate emphasis was placed on the importance and function of gas and the need for conserving gas pressures. More recently, disproportionate emphasis has been placed on encroaching edge water. Only lately has there been evidence that the function and importance of gravity was to receive due consideration. Study of this neglected phase of oil recovery is needed to round out our knowledge of reservoir behaviors and to gain a balanced viewpoint of the interplay of forces that may operate in varying importance in reservoirs. The purpose of this paper is to discuss mainly in a qualitative way, the functions of gravity, to present some concrete instances where it has been important and to raise some questions that should be investigated further. Oil-recovery Agents The important natural agents for effecting oil recovery that may be originally available in a reservoir are gas, both dissolved in the oil and free in gas caps, encroaching edge water and gravity. Each of these agents can act in a dual capacity—physically to overcome the surface energies that hold the oil within the pores and mechanically to overcome viscous . resistance and to propel the oil through the porous reservoir rock to the wells. Advancing edge water displaces the oil from the pores and lifts it updip to structurally lower wells. Gravity drains the oil from the pores and flows it downdip to the wells. Gas displaces oil from the pores, entrains it in the gas stream and flows it to the wells, but gas in solution also affects the physical properties of the oil and thus can influence oil recovery by the other agents, whether or not the mechanical energy in the gas is utilized. Of the two functions of these agents, the more important is the ability to dis-

Jan 1, 1944

By James O. Lewis

Gravity drainage is the self-propulsion of oil downward in the reservoir rock. Under favorable natural and operational conditions, it has been found to effect recoveries comparable to water displacement. With modern technical knowledge, the operator can often make a choice between dissolved gas drive, water drive and gravity drainage as the principal recovery agent in a reservoir. It is desirable that the opeator be able to determine which of the three agents will be most effective under each set of conditions. So far, gravity drainage has received less consideration than the other two. In this paper. an endeavor is made to set forth some of the principles of gravity drainage, to point out the types of reservoirs favorable for it, and to show how it may be applied in them. Field examples are described and discussed. Introduction Since early in the history of the oil industry, it has been recognized that gravity is one of the three important natural forces for expelling oil from the reservoir rock. As knowledge of the technology of oil recovery progressed, ideas changed with respect to the relative importance of the three forces and with respect to the manners in which they functioned. For a time, disproportionate emphasis was placed on the importance and function of gas and the need for conserving gas pressures. More recently, disproportionate emphasis has been placed on encroaching edge water. Only lately has there been evidence that the function and importance of gravity was to receive due consideration. Study of this neglected phase of oil recovery is needed to round out our knowledge of reservoir behaviors and to gain a balanced viewpoint of the interplay of forces that may operate in varying importance in reservoirs. The purpose of this paper is to discuss mainly in a qualitative way, the functions of gravity, to present some concrete instances where it has been important and to raise some questions that should be investigated further. Oil-recovery Agents The important natural agents for effecting oil recovery that may be originally available in a reservoir are gas, both dissolved in the oil and free in gas caps, encroaching edge water and gravity. Each of these agents can act in a dual capacity—physically to overcome the surface energies that hold the oil within the pores and mechanically to overcome viscous . resistance and to propel the oil through the porous reservoir rock to the wells. Advancing edge water displaces the oil from the pores and lifts it updip to structurally lower wells. Gravity drains the oil from the pores and flows it downdip to the wells. Gas displaces oil from the pores, entrains it in the gas stream and flows it to the wells, but gas in solution also affects the physical properties of the oil and thus can influence oil recovery by the other agents, whether or not the mechanical energy in the gas is utilized. Of the two functions of these agents, the more important is the ability to dis-

Jan 1, 1944

C. A. Stetefeldt, San Francisco, Cal. (communication to the Secretary): In view of Mr. Louis's statement that the balance and weights employed in his experiment were '(by no means first-rate," the results can scarcely be entitled to weight. And if a slight variation in specific gravity were to be accepted as proof of the existence of allotropic modifications, we should be obliged to conclude that every metal existed in such modifications. When the observed specific gravity of an alloy (as is often, and perhaps generally, the rase) differs from the calculated one, it seems more reasonable to explain the difference (apart from errors of determination) by assuming that actual chemical combination takes place between some atoms of the metals. MR. Louis (communication to the Secretary): In reply to the criticisms with which Mr. Stetefeldt has favored me, I beg to point out to him that, in the first place, I do not myself attach very much weight to the results I have obtained. I merely claim to have pointed out that amorphous gold obtained from dissolving up the alloy with silver has a higher specific gravity than common gold—a result corroborated by the quoted results of Rose. At any rate, it is easy to repeat my observations, and I hope this may be done by men who have better opportunities than myself for this investigation. Surely it is worthy of attention from assayers at the mints. I am not prepared to say that I should regard slight variations in specific gravity as absolute proof of allotropism, but I do consider

Jan 1, 1894

By F. P. Dewey

The subject of this paper does not embrace the consideration of ways and means for the increase of analytical accuracy, or the question what could or should be attained in that direction. I desire simply to call attention to the degree of accuracy exhibited in actual every-day practice. In estimating this, little weight will be given to the evidence afforded by the agreement of duplicate or multiple determinations by the same chemist; for I am convinced that such agreement is a delusion and a snare. Nor will special importance be attached to the agreement of two or even three analyses in special cases, or to the agreement between two methods practiced by the same analyst. I propose to compare the results obtained by several chemists, working upon the same sample and by various methods, in order to exhibit, as I have said, the actual condition of practice. The available material for illustrating this phase of the question is unfortunately scanty; but something has been done; and I hope, by calling attention to some of the work in this line, to stimulate further work in the same direction by inducing others to prepare suitable samples and submit them to various chemists who are competent and willing to make the necessary determinations, and fully describe the methods they employ. I draw most of my illustrations from the Transactions of the Institute, the Proceedings of the Association of Official Agricultural Chemists, and from personal experience. Manganese in Steel.—In May, 1881, Mr. William Kent presented a paper to the Institute entitled " Manganese Deter-

Jan 1, 1897

By Fred Witt, Milton Schwartz

ESTABLISHED methods for obtaining quantitative pole figures for flat sheets1"5 can be extended to apply to thin films on a substrate. The mode of scanning the sample is exactly the same as described in the references? but consideration is given to the fact that the scattered X-ray intensities are due to both the thin film and its substrate with appropriate attenuation factors. The purpose of this paper is to describe a method to obtain the scattered intensities from the film alone for subsequent pole-figure determinations. Fig. 1 shows the four possible general positions of the film (f) and its substrate (s) with respect to the incident X-ray beam (I,). In this paper it will be assumed that the plane of the sample is normal to the plane of the diffractometer. In the diagrams the line jV is the normal to the flat sample and the line P is the trace of the diffracting crystallographic planes in the plane of the diffractometer. The angle of tilt, a, is the positive acute angle measured from the line N to the line P; if this angle is measured clockwise then a is said to be in the positive a region; if this angle is measured counterclockwise then a is said to be in the negative a region. For the reflection cases, the total scattered intensity, at the proper Bragg angle for a particular set of planes, is due to that scattered by the film Vf) and that scattered by the substrate. The beam incident on

Jan 1, 1967

As it is the plan of the War Department to return 400,000 soldiers a month during the next four months, Colonel Arthur Woods, Special Assistant Secretary f War, has requested the Engineering Societies to assist the Government by soliciting their members to advise the respective societies, at the earliest possible moment, f any place where companies can employ returned soldiers. This request applies not only to the professional men who are returning but also to the miners, mechanics and other skilled labor among the enlisted men. Army discipline has not only made these men think more quickly but also more willing and obedient workers. The whole training has been conducive to regular habits and clean living steadying these men and fitting them to meet emergencies more quickly and has instilled more loyalty to their superiors and to their jobs. Further, the military instruction they have received has increased the men's powers f concentration. The War Department cannot too strongly bring before the employers of skilled labor the fact that the employment f discharged soldiers will be advantageous to the employer and economically beneficial to the country. The following is a list of the vocations of the men who are now returning:

Jan 6, 1919

By John V. Beall

It is difficult to understand why they did it. It was a demonstration of total commitment which sent chills of mixed admiration and fear up and down your spine. The scene was the bodega in Section A, 2660 Level on the 12 to 8 shift. The jefe was patiently waiting for the tea leaves to settle in a large metal cup. His attention was distracted by the appearance of a miner who had a problem. The long and short of it was that the miner believed the branch raise he was driving was unsafe and he wanted the jefe to come and see it. After lunch the jefe went around. First cautiously shining his light to peer up the raise from outside the chute, he then scrambled inside and swiftly climbed the cribs to the face. No question, it was hairy; about 4 crib sets were needed to catch up to the face. The unsupported raise was slabbing. It didn't take the jefe more than a few seconds to ascertain this situation and to slide back down. As he came out of the chute, a small avalanche arrived on his heels and provided a sort of exclamation point to his order; "cerrado!" In other words, shut 'er down.

Jan 1, 1970

NOW continuing with the preparation of the moulds I say that it is necessary to give the greatest attention to the differences of the clays as well as to the differences of those things that you wish to mould; and to know that every concavity in the mould produces a convexity and every convexity a hollow following the shape of the original pattern that you have. The pattern should be a body of a harder mated than the thing [78] you wish to mould with and of a substance that is not swollen or disintegrated by moisture. Its archetype may be of marble, bronze, lead, or any other metal, or also of wood, wax, tallow, gypsum, sulphur, or other plaster compositions-in short, of whatever you may have or whatever succeeds best for you, depending on whether the works are large or small and easy or &cult to mould. If you wish to cast them in bronze, you must mould them with loam, covering them with it and then drying it. There are some things in which it is enough to form only one part, such as half- or bas-reliefs. These are easy if they have no undercuts. Some other patterns that are easily handled are formed in two halves, or in three or four pieces, if they are of a hard material. There are also moulds for large statues, which, if one desires to make them of bronze, are first made of wax according to the ordinary procedure. I have in mind to describe every one of these processes in their own place. There are like- wise some moulds that are difficult to make, like scenes on a plane to which figures in full relief are attached, or twisted ornaments or other detached things that cannot be withdrawn from the mould without break-

Jan 1, 1942

By M. R. Louthan

The susceptibility of titanium to stress orientation of hydride precipitates was investigated. It was determined that, when hydride precipitation occurred in titanium under an applied tensile stress of 30,000 psi, the hydrides precipitated on the titanium habit plane oriented most nearly perpendicular to the stress axis. Stress orientation of the hydride platelets occurred because the precipitation of the lower density hydride phase perpendicular to the stress axis caused expansion of the matrix in a direction that tended to relieve the applied stress. The Ti-H system has received considerable study in recent years, mainly because of concern over the effects of hydrogen on the mechanical properties of titanium. The amount of hydrogen present in commercial titanium is now quite low and should have no appreciable effect on its mechanical properties; however, many titanium applications require ex- posure to hydrogenous atmospheres under conditions in which hydrogen pickup is likely. In such cases continued exposures may cause the hydrogen content to increase to the extent that titanium hydride does precipitate as a second phase. The hydride phase has been shown 1,2 to have an adverse effect on the mechanical properties, particularly the impact properties, causing reductions in strength and ductility. BACKGROUND The behavior of titanium is often quite similar to that of zirconium and zirconium-base alloys, and the technology developed on one metal can often be applied to the other. Marshall and Louthan3,4 have shown that Zircaloy is susceptible to stress orientation* of zirconium hydride platelets, and that the platelet orientation has a pronounced effect on the mechanical properties of Zircaloy. They showed that when zirconium hydride precipitated in Zircaloy under an applied stress the hydride platelets tended to be aligned parallel to a compressive stress and perpendicular to a tensile stress. They also showed

Jan 1, 1963

By Michael B. Jones, Wayne R. Bruce, Cyrus W. Field

For more than a decade the Pacific Northwest has been a frontier of successful porphyry copper-molybdenum exploration. This vast region (about 2100 miles long, 350-500 miles wide) occupies a geologically complex mobile tectonic belt. It parallels the Western Cordillera from northern California-Nevada to southern Alaska-Yukon Territory, and west from the northern Rocky Mountain-Tintina Trenches to the Pacific margin. Right lateral displacement has occurred along major transcurrent faults that are sub parallel to the region and the transform Fairweather-Queen Charlotte fault zone separates the North American continental plate from the Pacific oceanic plate. Porphyry-type deposits are widespread, but producing mines are restricted to south and central British Columbia. Size and grade are variable (25 to +300 mt; 0.18 to 0.65% Cu with 0.014 to 0.049% MoS2; 0.14 to 0.28% MoS,) and secondary enrichment is normally unimportant. Metallization is genetically and spatially related to late quartz-feldspar porphyries that are within, marginal, or satellitic to composite batholithic intrusions. Radiometric ages of the plutons range from Miocene to Triassic-Jurassic (18 to 217 m.y. [million year] ). Country rocks are typically eugeosynclinal metasedimentary and metavolcanic assemblages of Permian to Jurassic age. Several of the older (pre-Late Cretaceous) deposits formed in submarine island arc environments and they may be genetically related to occurrences of volcanogenic sulfides in the greenstone country rocks. Deposition of bornite-chalcopyrite-molybdenite ores is controlled by contacts, breccias, and fault-fracture zones. Associated hydrothermal gangue minerals include biotite, orthoclase, sericite, kaolinite, quartz, anhydrite, and tourmaline. Isotopic data suggest a deep source for ore, gangue, and plutonic host rocks. Significant exploration features include porphyries, dike swarms, breccias, potassic alteration, barren quartz cores, gossans, and fringing halos of pyrite and propylitic alteration.

Jan 1, 1975