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The Joint Economic Committee's subcommittee on international payments and exchange has recommended that, following international monetary reforms, the law which prohibits private possession of gold by American citizens be repealed. The subcommittee recommendation called for reforms to enhance the role of special drawing rights in international monetary affairs and downgrade the role of gold. Special drawing rights, also known as "paper gold", are on artificial reserve with the International Monetary Fund (IMF) which distributes them to member nations in proportion to their economic importance in the world economy. The special drawing rights are then used to settle debts between nations in the same manner as gold or currency. The subcommittee said that under the reforms now being discussed special drawing rights would be acceptable in lieu of gold among the member countries of the IMF.

Jan 1, 1973

By H. W. Morse

The experimental work on the oxidized copper ore at the New Cornelia mine at Ajo, Ariz., ended on Jan. 12, 1916. On that date final decision was made on the general nature of the process to be used in the 5,000-ton leaching plant, and on many of the details, as far as experience on a 40-ton scale could decide them. With the approval of the Board of Directors and the General Manager, John C. Greenway, we have compiled what seem to be the most interesting data on the results obtained during the experimental period. The most important part of the data resulted from the operation of a 1-ton and a 40-ton plant at Ajo. Experimental work on Cornelia oxidized ore dates back to April, 1912, and has been going on nearly continuously since that time. A good many variations from the original idea have been tried, but the process finally decided upon is in principle and in all of its details a simple one. The history of the leaching work on this ore has been brought down to about a year ago in papers presented to this Institute by Stuart Croasdalel and Dr. L. D. Ricketts.2 The present paper will, therefore, deal principally with the results obtained during the last year of the work. Preliminary Tests by Mb. Croasdale Preliminary tests were begun by Stuart Croasdale in July, 1912. A number of important points were definitely decided by his work. Among these were: 1. New Cornelia oxidized ore, not very finely crushed (to about 2-to 3-mesh) showed good extraction with 5 per cent. sulphuric acid. It appeared that better than 80 per cent. extraction could be expected. 2. The consumption of acid for this extraction was not prohibitive. It was apparently 3.5 to 4 1b. gross per pound of copper recovered.

Jan 1, 1917

By D. Turnbull, J. C. Fisher

ACCORDING to the "reaction-path" modell,2 of martensite nucleation, the shear angle of the embryonic martensite plate must be treated as a variable, and included in any calculation of nucleus critical size. Also, as can be deduced from this model, the interfacial free energy between austenite and martensite does not reach its final value until the shear is completed. It is zero for zero shear angle. However, in order to account for the kinetics of the martensite transformation, some sort of interfacial energy barrier appears to be necessary even with the reaction-path model, for otherwise the volume and the energy of formation of the critical size nucleus both collapse to zero.3 Cohen independently suggested that surface energy could be incorporated into the reaction-path model, with the overall free energy of a martensite embryo being a function of its volume and shear angle.' It is possible to estimate the energy associated with the formation of a critical-size martensite nucleus starting with the reaction-path model and including a surface free-energy barrier. As the dependence of interfacial free energy upon shear angle is unknown, a simple type of dependence will be assumed, with the belief that the true dependence would not lead to appreciably different results. Consider the work required to form a lenticular martensite plate with radius r, thickness t, and shear angle 8. There are three contributions; one being the interfacial free energy, one being the free energy change in the martensite plate, and one being the free energy increase in the surrounding austenite. The interfacial free energy u is assumed to depend upon the shear angle 0 according to the relationship s=s0(?/?0)n [1] where 8, is the equilibrium shear angle and n is an exponent that may lie in the range 0 n 2. The work required to form the interfaces of a martensite plate then is W. = 2pr² s0(?/?0)n [2] The free energy change per unit volume of martensite is composed of two parts, one the ordinary volume free energy ?f1. which is negative, and the other the elastic strain energy G?m²/2, where G is the shear modulus and 7, the shear strain relative to the martensite structure. This expression for the strain energy is valid only when the shear strain ym, is sufficiently small that the martensite is within its linear elastic range. There is no doubt that ym, lies beyond the linear elastic range for embryos that are considerably subcritical. However, for critical nuclei it will be shown that ym, is 1.5 pct or less, within the linear elastic range of martensite. For embryos of nearly critical size, then, the strain energy of the martensite is correctly given by G?m²/2. The shear strain in the martensite is ym, = 8, — 8, and the work required to form the strained martensite is Wm --= (pr²t/2) [?fv + G(?O - ?)²/2] [3] The free energy change in the austenite is entirely that due to elastic distortion. The elastic strain is not uniformly distributed in the austenite, being large near the martensite plate and small elsewhere. Approximately, however, the energy corresponds to a uniform shear strain ya= (?t/2)/r [4] throughout the volume 4pr³/3 surrounding the plate. The work required to strain the surrounding austenite then is Wa = (4pr³/3) (G?a²/2) = (G?²/6) prt² [51 For simplicity, the same shear modulus G is assumed for each structure. The total free energy for forming a plate then is W = W3 + Wm + Wa. = 2pr² s0 (?/p?0)n + (pr²t/2) [?fr+G(?0-?)²/2] + (G?²6) prt2 [6] This expression is correct for nuclei and for embryos of nearly critical size, where, as will be shown, the strain energy in the martensite is correctly given by the expression G (? — ?)². Having W as a function of r, t, and 8, as in Eq. 6, there is a saddle-point where W has a stationary value, W subsequently decreasing indefinitely as the nucleus volume increases along the reaction path. The stationary value of W is the energy of the critical nucleus. The critical nucleus has radius, thickness, and shear angle such that ?W/?r - awlat: = ?W/?p? = 0. Performing these differentiations and calculating the critical nucleus energy, W* = [8192p(G?/6)²;s/27 ?fv4] [7] where a= (?/?0)3n+1[l +G(8"-8)'/2af.]' [7a] and where 8 is to be determined from the equation (1 + 3n/4) + G8(6O - (9)/[Af. +G(6>o-6>)72] = 0 [8] For ?f, near —200 cal per mol or —10" ergs per cc, and 8, near 1/6, as for iron-base alloys, Eq. 8 gives ?0 - ? ~ - (4 + 3n) ?f1./4G0O [9] as the difference between the equilibrium shear angle and the actual shear angle for a critical nu-

Jan 1, 1954

By E. J. KENNEDY

FEBRUARY 15-18 will be the outstanding dates of the month for members of the A. I. M. E., for then the 141st Meeting of the Institute is to be held in the Engineering Societies Building, at New York. What with 41 technical sessions, the Annual Business Meeting at 4 o'clock Tuesday afternoon,, two sessions of the Section and Division delegates, minor committee meetings, and the many luncheons and dinners, the Dinner-Smoker, Informal Dance, President's Reception and the Dinner-Dance, the opportunity will be limited to do- more-than cast sheep's eyes at New York's other multitudinous attrac¬tions until the meeting is over. The technical program is diverse but well organized. The sessions are almost equally divided among the four days, with ten on Monday, Tuesday, and Wednesday, and 11 on Thursday. The meeting opens Monday morning with registration. Be sure to attend to this detail. Failure to do so may have its repercussions at the meeting and throughout the year.

Jan 1, 1932

The Institute conducts jointly with the American Society of Civil Engineers, American Society of Mechanical Engineers and American Institute of Electrical Engineers, certain activities as listed below, and is joint owner with them of certain properties. United Engineering Trustees, Inc. When Mr. Carnegie made his gift which made possible a home for the engineering societies, a separate corporation was organized to act as a holding company and to manage the common property. This was long known as the United Engineering Society, but the name has now been changed. to one which more nearly reflects the real function of the corporation. It holds title to the Engineering Societies Building and to various funds placed in its charge and is managed by a Board of Trustees, of which three are chosen by each of the four societies, American Institute of Mining and Metallurgical Engineers, American Society of Mechanical Engineers, American Institute of Electrical Engineers and American Society of Civil Engineers, which have equal and undivided interests in the property. The land and building cost two million dollars. During the gear 1934, the constitution and By-laws of The United Engineering Trustees, Inc., were thoroughly revised and a better organization of its functions was affected: The Engineering Foundation and the Engineering Societies Library were made "departments? of the United

Jan 1, 1936

By W. B. Boggs, J. N. Anderson

An account of the operation of the Noranda smelter covering the period from December, 1927, when the smelter started, until December, 1929, was given in a paper published by the Canadian Institute of Mining and Metallurgy early in 1930.' The object of the present paper is to review matters of interest in the original paper and to describe the present construction and operation of the smelter, with particular reference to the reverberatory-furnace practice. The Noranda smelter was built by Noranda Mines, Ltd., from the designs of A. E. Wheeler, consulting metallurgist of New York, for the reduction of ores and concentrates from the Horne mine and to treat, on a custom basis, ores and concentrates from other mines in the Rouyn district. The smelter is at Noranda, about 330 miles directly north of Toronto. Construction work was started in June, 1926, and copper was first produced in December, 1927. The smelter was built throughout as two duplicate units, each with a rated capacity of 500 tons of ore per day. Operations were started with one unit and after several months it was found that one unit alone could smelt 1000 tons of ore a day. At that time there was only one hoisting shaft, No. 3, and its hoisting capacity and the capacity of the original crushing plant were insufficient to supply ore for the two units at the increased tonnage. Accordingly No. 4 shaft was sunk and a new crushing plant provided to handle the ore hoisted there. Operating two units at capacity also required the installation of two more converters to treat the additional quantity of matte produced. This work was completed in the latter part of November, 1929, and since then both smelter units have been operating continuously. In 1928, a mill to treat 500 tons a day of concentrating ore was completed. Since then the concentrator capacity has been increased twice, and at present 2000 tons a day of ore are being concentrated. The layout of the surface plant of the mine, concentrator and smelter is shown in Fig. 1 and the general plan in Fig. 2. The smelter is shown in more detail in Fig. 3. The original hoisting shaft, No. 3, is now used only for handling men, supplies and waste rock, and the original crushing

Jan 1, 1934

By J. W. Dougherty, J. M. Douglas

THE Hollinger gold mine is in the Porcupine mining division, District of Cochrane, in the northern part of the Province of Ontario. The adjacent town of Timmins, with a population of 25,119, lies 490 miles by railway north of the city of Toronto. GEOLOGY The property is situated on the northwest limb of a major syncline, which pitches northeast at approximately 50°. The principal rocks of the Hollinger area are of pre-Cambrian age and consist of altered, schistose, Keewatin lava flows intruded by stocks of schistose, quartzfeldspar porphyry generally assigned to the Algoman period. The structure of the Keewatin series is extremely complex as a result of close folding and some faulting. The schistosity, trending north 70° east and dipping steeply to the southeast, is most highly developed along a subsidiary anticline in which the major porphyry bodies occur. The ore bodies, which exhibit three principal structures, consist of quartz veins and associated pyritized wall rock. Some lodes are composed of en echelon veins, others exhibit a main quartz body with branching stringers and a third consists of a single definite lead. Gold, in a coarse visible form, may be confined to quartz in some ore bodies but in others it is finely divided and is found not only in quartz but also associated with pyrite in the adjacent wall rock. In many veins the distribution of gold is such that there are several ore sections, separated by areas of low-grade material, in the same vein although its physical appearance remains unchanged. The veins form a very complex pattern in an ore zone which in places attains a length of 6000 ft. and a width of 4000 ft. They are most abundant in the Keewatin lavas in the neighborhood of the porphyry bodies. Few of the veins are persistent for long distances, though some

Jan 1, 1940

By E. W. Pehrson, J. W. Furness

THE five charts presented here- with are part of an original group prepared by the U. S. Bureau of Mines showing the international trade in the principal metals and metallic ores. Charts 011 anti- mony, chromite, copper, lead, manganese, mercury, nickel, tin, tungsten, and zinc were published in the February, 1936, issue of the Engineering and Mining Journal. Those shown here include bauxite, aluminum, iron ore, pig iron, and the platinum-group metals.

Jan 1, 1936

By H. W. Hardinge

DISREGARDING for the present the economic side of a new device, let us turn to that feature of the conical pebble-mill which is of interest from a scientific point of view, and consider the device as a puzzle in which the theories of the cylindrical type of mill have been increased. Many articles have been written on the theory of the tube-mill, and explanations have been made which do not explain.; but these have evolved suggestions of practice which have resulted in changes in the tube as to length, diameter, feed, discharge, speed of rotation, rotation on hollow trunnions, rotation on rings, and changes in the operation as to quantity and size of pebbles, charge of load above or below the axis, crushing by causing the larger pieces of the material of the charge to act as grinders, etc. The practical worker in crushing is first interested in the endeavor to reach an economic means of accomplishing a desired end; but the improvements in crushing-practice have been largely left to the manufacturer of machinery, who, as a rule, has little, if any, knowledge of the specific requirements-such as sizing for concentration without pulverizing the metals, instead of pulverizing the rock or gangue; the metals being the more friable, while the rock is tough and not so easily disintegrated. A reversal of this practice is the aim of sliming direct for cyanidation. In the ordinary cylindrical mill, having a diameter of 4 or 5 ft. and a length of from 15 to 27 ft., it has been found that the maximum size of the particles of the charge must not exceed 1 mm. (about 25 mesh), some of which, upon entering the mill, is immediately reduced to a slime. The work upon the individual particle having been finished, it should be passed out of the mill; but, instead of this, the finely comminuted material

Jan 7, 1908

By W. C. PAGE

AS the pioneer operation treating the mixed lead- zinc-iron ores from the district tributary to the Salt Lake Valley, the International Smelting Co.'s plant has offered an extremely interesting and instructive opportunity to study some phases of this problem. Basically, there were two main reason for our attempting to work out a successful operation for the separation and concentration of the values contained in the rather widespread deposits of these so- called lead-zinc ores. In the first place, the time was ripe and demanded some method of curtailing the economic waste resulting from the costs of past and present practice of smelting ores of this character, or rather, those ores which could stand the charges inherent with smelting them. Secondly, but rather primarily with us, we believe that such a solution would greatly in- crease in general the production of lead in the district tributary to the Salt Lake Valley. It is generally known that there were and are three relatively large lead smelting plants in the Salt Lake Valley and the decreasing production of correspondingly clean lead ores was not efficient to justify the existence of all three. We could not hope for better lead smelting metallurgy nor more efficient business management than was being practised, so the only prospect was to at- tempt to work out some way to increase the primary production and thus widen the scope of operations.

Jan 1, 1926

By Harold Price

PRIOR to Sept. 1, 1928, there had never been constructed what might be termed a long pipe line with electric-welded field joints. Nevertheless, by Sept. 1, 1929, within the period of a year, more than 2500 miles of electric-welded lines have been completed. These lines vary in diameter from 6 to 20 in., and in length from 50 to 700 miles. Before Sept. 1, 1928, no such line had been constructed .longer than 50 miles, and only one of nearly that length, a 40-mile 7-in. gas line in Louisiana. This was in reality the first pipe line to use electric-welded field joints. During the past year the following lines have been electric-welded by the Welding Engineering Co. alone: Texas Pipe Line Co.-157 miles of 8-in. line from Corsicana, Texas, to San Augustine, Texas. (This was the first electric-welded oil line.) Texas Pipe Line Co.-80 miles of 8-in. from Lafors, Texas, to Childress, Texas. Texas Pipe Line Co.-39 miles of 10-in. from Monahans, Texas, to Jal, New Mexico. Texas Pipe Line Co.-50 miles of 6-in, from San Antonio, Texas, to San Marcus, Texas. Texas-Empire Pipe Line Co.-424 miles of 12-in. from Cushing, Okla. to Chicago, Illinois. In addition to the field welding mentioned above,1 250 miles of 12-in. line was electric-welded into double joints at the pipe mill at Indiana Harbor, Ind.

Jan 1, 1929

By Benjamin Miller

FROM earliest recorded times, limestone has been employed in the industrial life of peoples of all sections of the world where it exists. It is widely distributed and therefore has been available in almost every country and has been employed for a variety of purposes. Its earliest use was for buildings, since it is more easily quarried and dressed than most other kinds of rocks and so could be utilized by early inhabitants, poorly equipped, with tools. The next use was in the manufacture of lime, which was employed by the ancients in mortar. These two uses of limestone are still all important, but they have been overshadowed in scores of regions by literally hundreds of new applications for raw lime-stone or products made from it. Anyone familiar with modern manu-facturing processes can quickly call to mind many industries in which limestones are essential, and new uses are continually coming to notice. Any enumeration would probably be incomplete and soon out of date.

Jan 1, 1935

By John D. Sullivan

Leaching of copper ores is a comparatively old art, probably dating back to medieval times. The leaching of mixed oxidized-sulfide ores, however, is modern. The first modern plant leaching mixed ores was at Ajo, Ariz., where commercial operations commenced in 1917. While the ore at Ajo was primarily oxidized there was always some sulfide present. The Inspiration leaching plant, which was put in operation in 1926, may be considered the first plant constructed for the extraction of both sulfide and oxidized copper. The pioneers in leaching mixed ores had a difficult task before them since they had very little fundamental data on the chemical and physical factors of leaching. For the very large amount of painstaking experimental work that was done before building the Ajo and Inspiration leaching plants the reader is referred to the original articles.' For a period of several years the writer worked on problems connected with the chemistry and physics of leaching mixed oxidized-sulfide ores. This paper summarizes the experimental work and discusses various factors involved in leaching ores. It also presents many data heretofore unpublished. Among the new data are those on chrysocolla, pages 518 to 519, inclusive; dioptase, page 519; covellite, page 529; virtually all those on chalcopyrite, pages 531 to 533, inclusive; enargite, page 533; and tetrahedrite and tennantite, pages 534 and 533. The oxidized copper minerals of commercial importance in American ores are azurite, Cu3(OH)2(CO3)2; malachite, Cu2(OH)2CO3; chrysocolla, CuSi03.2H2O; tenorite (or melaconite), CuO; and cuprite, Cu2O. Dioptase, CuSiO3.H2O is less common. Brochantite, CuSO4.3Cu(OH)2, while the chief mineral in the ore at Chuquicamata, is not of major importance in the United States. Metallic copper, while chemically not so, is frequently classed as an oxidized mineral of copper. The most important sulfide minerals are chalcocite, Cu2s; covellite, CuS; bornite, Cu5FeS4; and chalcopyrite, CuFeS2. Less important complex sulfides are enargite,

Jan 1, 1934

By T. A. Wright

THE SAMPLING of waste materials containing copper, lead and tin has taken on a new significance within recent years, and is of increasing importance, on account of the entry of some of the copper refineries into this field and the tendency towards consolidations among the smelters. In the past, such material was sold on the basis either of a rough or grab sample or of casual inspection of the lot. The two principal sources of this waste are the processes of fabrication and the scrapping of automobile, electrical, plumbing, railroad and other equipment. In both cases much material can be sorted, salvaged and sold by classification and grade to be melted "as is" or with the addition of new or virgin metal. The increasing care in classifying exercised in the large manufacturing plants tends to increase the proportion of this usable scrap; on the contrary, the increasing use of more complex and special non-ferrous alloys tends to make sorting and grading more difficult in turnings, borings, clippings, etc., and consequently is making sampling of more moment. In tin, lead, aluminum, and zinc furnace by-products such as ashes, drosses, skimmings, etc., the trade practice of evaluation has not varied much. For instance, tin drosses, battery lead, and aluminum skimmings are ordinarily sold on what is called "metallic button" or "metallic recovery" or "metallic yield." Copper and lead waste, however, is being sold more and more on actual copper and lead contents based on sample and chemical analyses. This paper will be devoted chiefly to the sampling of materials suitable only for refining and recovery of one or more of the metals present. The methods described are often based on the fact that but one metal, such as copper, is to be paid for. The loss of volatile constituents in melting does not appreciably affect the final copper result, as the "after-melting" assay can he readily calculated to the "before-melting" basis, but if smelter efficiency continues to increase, so that in time zinc, for instance, may be recovered on a paying basis, the method of sampling dirty brass, for example, will have to be changed also. As a matter of fact, we may expect that improved refining processes will make possible the partial recovery of lead and tin which are now lost.

Jan 1, 1928

By W. J. PRIESTLEY

WHEN during the war the Navy Department decided to build an armor-plate and gun-forging plant of its own at South Charleston, W. Va., one of the most important units of the equipment proposed was a 14,000 gross ton forging-press to be used for forging, bending, and rectifying battleship armor-plate and making hol¬low forgings for large caliber guns. A press suitable for doing this kind of work was put into operation in the fall of 1921 and was operated successfully on armor-plate and large forgings until the closing down of the ordnance plant following the Limitation of Armament Conference held in Washington, February, 1922. PURPOSE OF THE PRESS There are three methods by which armor-plate can be made, namely, hammering, forging, and rolling the ingot. Each method produces a different result in the mechanical working of the steel. The hammer was eliminated as impractical from an operating standpoint. The first armor-plate made in this country was worked under a hammer at the Bethlehem Steel Co., between the years 1891 and 1893, but was superseded by forging when the large press was completed in 1893. Harry T. Morris of the Bethlehem Steel Co. informs me that the 1.25-ton steam hammer began operations in 1891 and was in operation for about two years. The Carnegie Steel Co. and the Midvale Steel and Ordnance Steel Co. also forged armor-plate. Certain European manufacturers rolled the plates from large slab ingots, after removing the sink-head and giving the body of the ingot a light pass under a hydraulic press. While rolling accomplished more mechanical work on the surface of an armor plate, forging, on the other hand, resulted in a greater amount of work in the interior of the plate. Either type of equipment involved an enormous expendi¬ture, so it was deemed advisable to adopt the method which would make it possible to use the equipment for more than one purpose. Since g large rolling-mill could be used only for the single operation of rolling armor-plate, a press was decided on, for the reason that it might be designed so as to forge armor, as well as bend and rectify it, and also be used in the forging of ingots for large caliber guns, both in the form of hollow forgings and also solid shafts.

Jan 1, 1926

By J. Campbell

The hydrostatic tensions in pure metals and long freezing range alloys are evaluated theoretically considering the viscous flow of residual liquid and the general plastic collapse of the casting. The former mechanism operates until the radii of the remaining liquid channels are of the order of 10-3 cm radius, after which the second process limits the attainable negative pressures which range from —1500 to -4200 atm for nickel, aluminum, copper, and iron. In previous reports1'2 the maximum possible hydrostatic tensions developed during solidification have been evaluated employing spherical symmetry. This inevitably involves the concept of totally confined liquid regions, the reality of which has recently been brought into serious doubt3 following observations of the freezing of various transparent materials. Regions of interdendritic liquid which are apparently about to be isolated by the growth of dendrite arms are observed not to be cut off because the advance of the dendrite tips is arrested until the region has completely solidified. Although this may be the result of the very low melting point liquid available at this late stage in freezing, or the result of a higher rate of heat transfer to the dendrite tips because of the acceleration in liquid flow rate near the completion of solidification, this point need not concern us. In this paper an attempt is made to approximate more closely to real conditions; thus the assumption of confined liquid regions is abandoned and cylindrical symmetry adopted. It has also been necessary, therefore, to consider the viscous flow of residual liquid through the remaining channels in the pasty zone. Furthermore, the rather special conditions of spherically symmetric solidification led to extremely high solidification rates and hence unusually high tensile stresses as solidification neared completion; the cylindrical Symmetry appears to yield solidification rates and stresses which are more typical of real castings. The rate of solidification is first considered since this critically affects both the flow of the liquid and the creep of the solid.

Jan 1, 1969

By Robert Hunt

ONE of the most serious and important economic administrative problems facing American railway authorities to-day is that of their rails, and it is one to which much thought, is being given, not only by the executive officers of the railways and the manufacturers of the steel rails, but also by State and National commissions. It is realized by many and admitted by some that the present situation is one which cannot continue. The roadways of railways must be made more secure, or the weight of rolling stock and the speed of trains must be lessened; and the desired result must be attained with the minimum outlay of money, both in expenditure on plant and in cost of operation. If the investment per mile is too large, or through the lessening of tonnage and efficiency of equipment the cost of operation is too great, the desired and demanded cheap service cannot he rendered to the public. Therefore, the weight of equipment cannot be greatly reduced, and lessening the rapidity of service would be far from satisfactory; consequently, the safety of the roadway must be secured with the least practical outlay. It is imperative that the roadbed should be properly graded, with the fewest practically possible curves; that it should have good ballast, be well drained, have good ties properly spaced, and be laid with sound rails of suitable weight, efficiently joined together, and that the whole property be carefully and intelligently cared for. My province is to treat of the sound rails. During the last few years there has been renewed interest in and discussion of that question, and I know that many rail makers not only have been and are desirous of maintaining the highest standards of manufacture which they may have attained, but have been and are seeking to better their product, in several instances devoting much time and money to that end. At the same time, they realize that the cost of any improvement in quality which they may accomplish must be kept within certain commercial bounds; and that fact is as fully understood by their patrons as by themselves, and it should be kept in mind by all who discuss the question.

Jan 2, 1914

By Warden A. Moller

(Pittsburg Meeting, March, 1910.) THE Fushun coal-field, now being opened up by the South Manchurian Railway Co., is connected with the main line by a branch, 30 miles long, from Sui Chia Tun, 10 miles south of Mukden, the capital of Manchuria. The coal-field, which lies on the southern bank of the Hun river, 25 miles east of Mukden, consists of a long narrow valley,. running east and west between hills composed of granitic and volcanic rocks. At the foot of the northern hills, the Hun river flows westward towards the Liao river, which drains the greater part of South Manchuria. At the foot of the southern hills, resting immediately upon volcanic rocks, and overlain by 20 ft. of alluvial, is a thick layer of Tertiary shales, carrying near the base two coal-seams. In many places the lower of these two seams is in immediate contact with volcanic lauds and basalts, the flows of which were evidently both prior and subsequent to the formation of the coal-seams. This contact has practically destroyed the lower seam for commercial purposes. The value of the field lies in the upper seam, which, for a length of nearly 8 miles, varies from 100 to 130 ft. thick. Of this seam, 85 per cent is good coal. The seam dips to the north conformably with the shales, at angles of from 25° to 30°, and appears to have an uninterrupted dip for about 1.5 miles before being possibly cut o$' by the northern hills. The coal-bearing shales extend east and west for a length of about 20 miles, but towards the east the continuity of the seams is broken by intrusive rocks. The coal is of the sub-bituminous variety, low in ash, bright in appearance, and breaks with a conchoidal fracture. It has the usual qualities of Tertiary coal-quick steam-raising and poor stacking-qualities. Pieces of resin, varying in size from

Apr 1, 1910

INTRODUCTION Conditions for formation of porphyry copper deposits appear to have been propitious in the Appalachian orogen from the end of Precambrian into Middle Ordovician, and again from Middle Devonian into Mississippian. In the Appalachians we can now record the evolution of a porphyry copper province within a developing orogen, one that reached metamorphic and structural maturity by the end of Devonian. Fig. 15, after Irwin and Coleman (1972), locates that portion of the Appalachian orogen included in this study, and Fig. 16 illustrates general geology of the area. Deposits mentioned in Table 3 and in the text are shown in Fig. 16. Data presented summarize personal observations by the author, published descriptions of specific areas noted in the bibliography, and abstracts from Provincial assessment files. Sources of previously published data are acknowledged. Few comprehensive descriptions of individual porphyry copper deposits in this area exist, so much of the data presented is new to the literature. Porphyry mineralization has, for this chapter, been restricted to porphyry copper de- posits, although porphyry molybdenum de- posits (Clark, 1972) are also shown in Fig. 16 (Hollister, et al., 1974). Copper- molybdenum and tungsten-molybdenum skarns are also omitted to simplify discu sion, though each is known in the area studied. Gaspe Copper is included, however; min- eralization in this deposit is present in the intrusion as well as in the skarn adjacent (Bell and Scott, 1954). Porphyry deposits listed in Table 3 are included because of some important feature, although other deposits have been reported (e.g., Kirkham and Soregaroli, 1975 ) . Clearly, no table now compiled could be complete. The pace of exploration insures that new occurrences will probably be found. Summaries of features exhibited by intrusions shown in Table 3 should remain valid, however, since they appear representative and are based on an adequate number of deposits in the area studied. Paleozoic porphyry copper prospects (shown in Fig. 16) are more common, apparently, in the northeastern part of the orogen, rarely having been found south of Catheart or west of the Logan Line. Occurrences of molybdenum and other associated lithophile elements are, however, known to the south and west as well as further north. Killeen and Newman (1965), King (1970),

Jan 1, 1978

[PAGE PREFACE. A. B. PARSONS 3 OFFICERS AND DIRECTORS 7 STANDING AND SPECIAL COMMITTEES 8 PROCEEDINGS OF 1935 MEETINGS 10 NEW YORK, FEBRUARY 10 CHICAGO, OCTOBER 14 SAN FRANCISCO, OCTOBER 14 HOUSTON, OCTOBER 15 ST. LOUIS, OCTOBER 15 ABSTRACTS OF PAPERS PUBLISHED IN 1935 17 TECHNICAL PUBLICATIONS AND CONTRIBUTIONS, 1935 64 INDEX OF 1935 PUBLICATIONS 71]

Jan 1, 1936