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This brief resume of events, transpiring in Mexico, culled from the daily New York newspapers, since the last Bulletin went to press, does not indicate any degree of improvements in the situation. GENERAL ALVAREZ COURTMARTIALED AND SHOT General Francisco Alvarez of the anti-Government forces was captured in the battle in which General Aureliano Blanquet, Minister of War in the Huerta Cabinet, was killed, and was sentenced by a courtmartial and shot in spite of a specific order of the Supreme Court in Mexico City that the execution should not take place. General Alvarez was a member of the staff of Felix Diaz, and was a veteran of the old regular army of Mexico. MEXICO WILL NOT RECOGNIZE MONROE DOCTRINE Failure of the Allied Powers to invite Mexico to participate in the conference of neutrals at Paris aroused President Carranza to bitter resentment, which was enhanced by the incorporation of recognition of the Monroe Doctrine in the covenant of the League of Nations without consultation with Mexico. Statements were issued by the Mexican Foreign Office disavowing adherence to the Monroe Doctrine and announcing the withdrawal of the Mexican representative in France. Carranza had been awaiting an opportunity to get his agent away from Paris for the real reason that he had been unable to secure recognition from either the French or the British Government. Mexico announces, says the New York Times editorially, that "she has not recognized and will not recognize the Monroe Doctrine." "Nobody has asked her to recognize the Monroe Doctrine," continues the editorial. "The enforcement of the principles enunciated by President Monroe does not depend upon Mexico, upon anybody's recognition or non-recognition. The countries concerned in the Monroe Doctrine are the United States on the one hand, and countries not of this hemisphere on the other."

Jan 6, 1919

By S. Froes

Official daily output of the Reconcavo (Bahia) oil fields, which amounted to 300 bbl., increased by the end of 1944 to 500 bbl. The new productive wells are in the district of Candeias. This figure is expected to further increase during 1945. The Itatig Company, which had drilled five wildcats in the state of Sergipe, stopped in 1944, but intends to resume work during the current year, or as soon as the war is over, in order to try the Cretaceous areas around its salt deposits. Several concessions applied for in the states of Sao Paulo, Parana arid Santa Catarina were favorably considered by the Conselho Nacional de Yetroleo, which is interested in fostering prospecting activities in the country. Several national groups are interested in exploring the federal gas field of Aratu (Bahia), a proposal having been made to use the gas in the manufacture of Portland cement. Undoubtedly the most important fact in the 1944 activities was the visit by two outstanding petroleum geologists, who had the opportunity to examine some of the principal areas and reported their opinions to the Brazilian Government. By special courtesy of the U. S. Government, Mr. E. DeGolyer spent a few weeks inspecting the gas and oil fields of the so-called "Reconcavo" of Bahia (a large tract surrounding All Saints Bay, on whose shore lies the city of Salvador) Later he exchanged ideas with Colonel Joao Carlos Barreto, President of the Conselho Nacional de Petrolco, as to the most adequate measures to develop production. Considering the oil problem in the southern part of Brazil, in the sedimentary belt including formations from the Devonian to the Triajsic, Mr. DeGolyer suggested a visit there by Mr. Lemis MacNaughton. The latter traveled during the months of June, July and August, accompanied by Brazilian geologists Avelino de Oliveira, Vice-president of the Conselho Nacionial de Pctroleo, Pedro Moura, Annibal Bastos, Burdot Dutra and J. Felicissimo, and verified the actual possibilities of the region, thus confirming the opinion of Pedro Moura, Avelino de Oliveira and Froes Abreu as to the advisability of thoroughly prospecting the south of Brazil. It is to be hoped that on the recommendation of these proficient American experts the Brazilian Government will take the necessary measurcs to carry out a complete search 01 such areas, which hitherto have been unsuccessfully drilled because knowledge of the structure was not adequate. The old Government policy of monopolistic essence has now given way to the more enlightened tendency of reconciling official action with private enterprise, which should in no way be curbed but rather encouraged. Such trend is heartily welcomed by financiers and technicians alike, who realize how indispensable is the cooperation of private capital, both national and foreign, in

Jan 1, 1945

This brief resume of events, transpiring in Mexico, culled front the daily New York newspapers, since the last Bulletin-went to press, does not indicate any degree of improvement in the situation. RECORDS OF 217 MEXICO KILLINGS SUBMITTED BY AMBASSADOR FLETCHER Henry P. Fletcher, the American Ambassador to Mexico, called as the first witness before the Rules Committee of the House which has begun a preliminary inquiry into conditions in Mexico, which, it, is believed, will lead to a thorough and far-reaching investigation by a joint Senate and House Committee of the entire Mexican problem, submitted a list of the names of Americans officially known to have been killed in Mexico, a majority of them murdered in cold blood, since the overthrow of Porfirio Diaz by Maderoin 1911. The list contains 217 names and in comparatively few instances do the records show that arrests were made by the particular Mexican faction that happened to be in power where the crime was committed. In only one instance, that of John B. McManus, who was killed in March, 1915, was reparation made. It is significant that McManus was killed by Zapatistas, and Zapata officials apologized for the crime and paid to Mrs. McManus a voluntary indemnity of $20,000 in gold. Of the 217 persons listed as victims of the Mexicans, .137 perished since Carranza came into power. The list, it was admitted, is not complete. It was evident, says the New York Times, that the Ambassador considered the situation very serious.

Jan 9, 1919

By George W. Friesen

This paper presents the historical trend and de- fines the causes of drilling cost escalation in the Gulf of Mexico during the 1970's. The three major components of escalation are: 1) inflation, 2) supply-demand imbalance (demand pull) and 3) decreases in drilling efficiency. The decade was divided into three periods. During each period one component of escalation was responsible for most of the rise in costs. From 1970 through 1973 only inflation pushed costs upward. During 1974 and 1975 a supply- demand imbalance caused most of the escalation. Since 1975, decreases in drilling efficiency have produced the major component of escalation. During any one year or period of years, the sum of the three components will give the total escalation rate. The reasons why different components contribute more toward escalation during certain years than others are shown by following the timing of oil and gas price increases, the overall quality of the acreage offered each year in offshore lease sales and the resulting drilling activity.

Jan 1, 1982

By R. U. Fitting, A. C. Bulnes

Field experience with limestone and sandstone production indicates the existence of wide differences between the reservoir behavior of these two types of formation. Little attention appears to have been given to the separate study of the flow of fluids and the retention of fluids in limestones. This paper presents data and arguments to demonstrate the existence of a difference between the two types of formation, and urges the separate intensive investigation of limestone reservoirs. AH experimental data presented pertain to dolomitic limestone formations in west Texas and New Mexico. Two kinds of Porous media are recognized— intergranular and intermediate. Intergranular rocks are those in which the porosity and permeability are determined by the geometrical properties and the sorting of the sedimentary units; intermediate rocks, those in which there is no direct relationship between grain properties and the porosity and permeability. Limestones in general are intermediate media. The partial relationship between porosity and permeability of any class of Porous media is represelried by an area of .finite extent and definite shape on the permeability-porosity plane. The horizontal and vertical variations of porosity and of permeability in limestone and sandstone formations are discussed and compared. Comparisons are made of connate-water content, the relative permeability-saturation relationship, and capillary phenomena in the two kinds of rocks. A number of tentative conclusions are drawn relative to the reservoir properties of lime- stones; in particular, (I) dolomitic limestones are oil bearing and apparently are oil productive in zones of permeability less than 0.1 millidarcyj and (2) primary depletion (by gas expansion) oil saturations may be lower in dolomitic limestones than in sandstones. Introduction It is well known that the reservoir performance of limestones displays numerous irregularities when compared with that of sandstones, and that the departures from "normal" behavior of limestones are more frequent and generally more marked than in sandstones. This is particularly true of fractured limestones and those that have undergone considerable development of secondary porosity' A review of the literature of production research published during the past 15 years reveals a startling absence of theoretical and experimental investigations directed specifically toward explaining and predicting the performance of limestone reservoirs, even. though such problems as the prediction of water encroachment and the estimation of ultimate recoveries continue at the "inspired guess" stage. By far the greater part of the experimental data reported pertain to measurements on sandstone core samples, while the theoretical studies, almost without exception, are developed from the assumption of an ideal porous medium and therefore seldom are applicable to limestone formations. The chief cause of this situation appears to be the common belief that, to all practical intents and purposes, sandstones and the majority of producing limestone formations

Jan 1, 1945

By D. J. Mack, R. E. Reiswig

Six examples of the peritectoid transformation were selected from the literature and studied by the method of isothermal transformation. The kinetics and mechanisms of five of the examples are presented as TTT diagrams and photomicrographs. The exist-enc- of a peritectoid in the sixth case is doubtful. ALTHOUGH the peritectoid transformation per se has been known for many years, no precise published data exist concerning the kinetics or mechanisms involved in transformations of this type, except for the brief treatment by Rhines, et al. 1,10 Bearing in mind the fact that investigations of recent years are uncovering more and more peritectoids and suspected peritectoids, a thorough study of the well-established peritectoids appeared to be in order. It was for this reason that a study of the kinetics and morphological mechanisms of six binary peritectoids was undertaken. The six peritectoids selected from the literature for study were those reported at 7.02 wt pct Al-Ag, 26.0 wt pct Sb-Cu, 30.5 wt pct Sb-Cu, 32.3 wt pct Sn-Cu, 8.35 wt pct Si-Cu, and 21.2 wt pct Al-Cu. These selections were based on availability and purity of components, ease of preparation and heat-treatment, and estimated reliability of the available equilibrium diagrams in the regions of interest. EXPERIMENTAL PROCEDURE The alloys used in this investigation were induction melted in electrode-grade graphite and chill-cast in cast-iron split molds. In all cases, the alloys were so brittle that they could easily be broken into samples weighing 1 or 2 g. Chemical analyses showed that the alloys used were close to the respective peritectoid compositions reported in the literature and that the impurity levels were low in all cases. Metallographic examination showed uniform distributions of phases in all samples, indicating uniformity of composition in the samples studied. Isothermal transformation studies were carried out in fused-salt media, using the familiar inter-rupted-quench method. Uniformity of temperature in the salt baths was maintained by continuous stirring with a stainless-steel agitator. On the basis of actual observations of the temperature fluctuations, the estimated temperature control was + 10C for the Ag-Al and Cu-Sb alloys and ±30C for the Cu-Sn, Cu-Si, and Cu-Al alloys. The accuracy of all temperature measurements was estimated to be ±1°C. It was found necessary to mount metallographic specimens of the Ag-Al alloy in cold-curing methyl methacrylate, since the temperatures encountered in mounting in bakelite or lucite caused an appreciable degree of transformation to the ß phase. For the other alloys, wood-flour-filled bakelite mounts were used to avoid extraneous X-ray diffraction lines during the later examination of the metallographic specimens on a Norelco Geiger-counter d if f r ac tomete r. In the X-ray diffraction procedure, agreement between the published diffraction patterns and those obtained in this study was good. This was particularly important for phase identification, since the literature contained little in the way of micrograph description in some cases. Etching of the silver-aluminum alloy for metallographic examination was done by swabbing with either of the following reagents: 1) 10 g CrO3, 1 g (NH4), SO2, 0.5 g NH4NO3, 100 ml H2O, or 2) 10 ml NH4OH, 1 ml 20 pct KOH, 4 ml 3 pct H2O2, 5 ml H2O. The other alloys were etched with the usual bichromate etchant: 2 g K2Cr2O7, 1.5 g NaC1, 8 ml conc. H2SO4, 100 ml H20 (swabbed vigorously). EXPERIMENTAL RESULTS A) The Ag-Al peritectoid at 7.02 wt pct Al— The phase equilibrium involved in this peritectoid is shown in Fig. I.2 The phase boundaries in the vicinity of the peritectoid were most comprehensively established by Hume-Rothery, et al,3 who placed the equilibrium temperature at 448 °C and the equilibrium compositions of the a ß' and y phases at 6.11, 7.02, and 7.24 wt pct Al, respective The alloy used in this study analyzed4 6.95 wt pct A making it slightly hypoperitectoid according to the accepted equilibrium diagram. The rate of the transformation a+ y — ß' varies rapidly with degree of undercooling below the equilibrium temperature, passing through a maximum in the vicinity of 350°C. Thus the TTT dia-

Jan 1, 1960

By Paul C. Merritt

The story now unfolding on the Mesabi Range is more than just another chapter in the continuing history of iron mining. It is an epic of foresight, research and pioneering instinct just now culminating in the rapid growth of a new industry hardly more than ten years old. And that growth has been impressive. In the decade that has passed since Reserve Mining Co. blazed a trail as the first successful large- scale commercial taconite operation, the number of plants now existing or soon to be operating has grown to six. From Reserve's initial capacity of 3 million tons of pellets per year, total production capacity on the Range has surged to 31.5 million tons while capital investment has leaped from $300 million in 1955 to almost $1 billion today. During the past year alone, more than $500 million has been committed to these projects, an amount probably greater than that going into any other single mining area in the world. There is more yet to come.

Jan 10, 1965

By A. G. Metcalfe

Observations at temperature are used to investigate the phase changes in alloys containing more than 50 pct Co and above 1000°C. The nonsuppressible transformations in cobalt above 1120°C and in the intermetallic compound Co2Cr3 are studied. The liquidus and solidus surfaces are determined. Insufficient data is obtained to complete the constitution diagram. A REVIEW of some of the earlier work on cobalt' and on the binary systems with chromium2-4 and with molybdenum,5 showed that one likely source of differences might be attributed to the presence of phases at high temperatures which could not be retained by quenching. Consequently, the decision was made that only methods of examination at temperature should be used in this work. The correctness of this decision was confirmed during the course of the work by the investigation of the martensitic nature of the transformation in cobalt- and by the decomposition of the high temperature form of the phase Co2Cr3 on quenching.' The use of high temperature methods, including dilatometry and thermal etching led to the postula-tion of the existence of a high temperature form of cobalt with a probable hexagonal close-packed structure, transforming from cubic cobalt over a range of temperature from 1119° to 1145°C.8 One of the important pieces of evidence for this transformation was that it was observed in alloys with chromium and molybdenum which were nonmagnetic at this temperature so that confusion with magnetostriction effects was impossible. These results were not reported in this earlier paper, so that the data given here supply further evidence for the existence of a second allotropic transformation in cobalt. High temperature observations are necessarily much slower in producing results than the examination of quenched specimens at room temperature by conventional means such as X-ray diffraction or microexamination. The investigation has only covered a limited part of the field, as a result, extending from the liquidus down to about 1050°C and from the cobalt corner up to 50 pct alloying elements. The differences between the various reported diagrams for the constitution of the Co-Mo and Co-Cr systems have already been mentioned. The best available diagram in the first system is due to Sykes and Graff' which is shown in Fig. 1. Fig. 2 shows the latest Co-Cr diagram due to Elsea, Westerman, and Manning.' A comparison reveals that these are incompatible because of the disagreement with regard to the number of allotropes of cobalt. Elsea, Westerman and Manning took their liquidus and solidus curves from Wever and Haschimoto.2 The temperature horizontal in the two-phase field beneath the eutectic was placed 35" to 39°C higher than in earlier work2,4 with a new interpretation of the nature of this transformation. This interpretation also required a peritectic horizontal at about 1470°C, which has been confirmed here for an alloy with 53 pct Cr. No investigation had been made of the ternary system until after this work had been terminated, when a section at 1200°C was published." In this work a ternary compound was found by the X-ray diffraction examination of quenched alloys. This compound contained less than 50 pct Co, and was thus outside the field investigated here. However, some reactions were found dilatometrically which could not be fitted on the diagram and are now believed

Jan 1, 1954

This brief resume of the events transpiring in Mexico, culled from the daily New York newspapers since the last Bulletin went to press, does not show any degree of improvement in the situation. MEXICO SEEKS TO AVOID BLAME FOR BANDIT RAIDS All foreign passengers leaving Nogales for Mexico on the Southern Pacific or Mexico Railroad. whose business would take them through territory occupied by the Yaqui Indians or Mexican bandits were requested by Mexican Consul Emilio Tamez to sign a statement that they relieve the Mexican government of responsi-bility for anything which might happen to them while in that part of Mexico. The Mexican consul stated, says the N. Y. Tribune, that this was by order of Mexican Ambassador Ignacio Bon ill as, at Washington. When the State Department was advised of this activity Secretary Phillips, in a message to the consulate at Tampico, according to the N. Y. Tribune, asserted that "compliance with the waiver requirement will not interfere with the relation existing between the United States and its citizens and that Americans so complying will in no way lose the protection of this government."

Jan 11, 1919

Major William R. Grunow, in a brief account off his military services, says: "I take pleasure in informing you that since my return from France I have been stationed at Camp A. A. Humphreys, Va., and am now on duty as a Senior Instructor at the Engineer Officers' Training School. While in France, I served as a company commander in the 305th Engineers and was later ordered to return to the United States for assignment to new troops. Upon arrival in the United States, I received my majority." P. F. Rodegerdts gives us the following account of his military service: "I enlisted in the Naval Reserve Flying Corps in San Francisco on Feb. 12, 1918. On February 10, I was ordered to Cambridge, Mass., where I was enrolled for the course in technical aircraft construction given at Massachusetts Institute of Technology. After successfully completing the course of instruction, I spent six weeks in practical construction of seaplanes at the Curtiss aeroplane factory in Buffalo. Following this, I was assigned to active service at Akron, Ohio, on June 22, 1918. At the same time I received my commission of ensign U.S.N. R.F. Unfortunately, I have been kept at Akron and although I have made

Jan 1, 1919

This brief resume of events, transpiring in Mexico, culled from the daily New York newspapers, since the last Bulletin went to press, does not indicate any degree of improvement in the situation. MEXICAN MINISTER TO FRANCE RECOGNIZED A dispatch from Paris quotes Alberto J. Pani, Mexican Minister to France, as saying lie lead received notification that lie might present his credentials at the French Foreign Office on May 13. This notice came at the moment the Mexican press was announcing his departure for Spain because of inability to present his credentials. MORE REVOLUTIONARY TROUBLES SOUTH AND NORTH Revolutionary outbreaks hulked large in advices from Mexico City at the end of May, says the New York Tribune. General Eznesto Danny, a major, four other officers and forty men, composing a train guard on the Isthmus of Tehuantepec Railroad, were killed recently in an attack by rebels under Felix Diaz's command. The troubles in the south, coupled with the fact that Villa's activities in the north have necessitated sending troops to campaign against him, have reacted in the capital seriously, it is reported. Military guards hi Mexico City have been doubled and machine guns have been placed on the roofs of the National Palace and the Cathedral. STRIKE AND MARTIAL LAW IN MEXICO CITY Advices from Mexico City, according to the Evening Sun, said that virtually every school teacher in the city was out on strike and that recurrent rioting was being put clown by armed trucks manned by Federal soldiers. The strike of the school teachers was clue to the fact that they had not been paid for months, but the direct incitement is said to have been the contrast between their impoverished position and that of Carranza's generals, who are described as rolling in wealth, and who flaunted their opulence on the streets of Mexico, riding about in high powered automobiles with women bedecked with diamonds and other jewelry. The city is said to be virtually under martial law with no immediate prospect. of a subsidence of the bitter feeling against the military caste.

Jan 7, 1919

By S. H. Davis

THE pyrites used in making sulfuric acid in the United States have been largely imported from Spain and Canada, the Spanish imports amounting to nearly 1,000,000 tons per annum in the pre-war period. The greatly increased use of sulfuric acid and the cutting off of these Spanish imports, incident to war conditions, brought about a threatened shortage of sulfur supplies during the war period. The bituminous-coal mines of certain districts have, for many years, furnished a small tonnage of pyrite in the form of coal brasses. A mechanical concentrator at Danville, Ill., for a number of years, has been treating hand-picked lump pyrite and coal from the picking belt and from the mines and a small plant near Gillespie, Ill., for a few months has been recovering pyrite from washery refuse. Many mines throughout Illinois, Indiana, Western Kentucky, Ohio, and Pennsylvania have shipped an occasional car of the hand-cleaned lump pyrite. Only a very small percentage of the available pyrite has been recovered in this way, however, as usually the miners throw such lumps into the gob with slate and other impurities. It has been estimated that the western Indiana coal field could furnish more than 100,000 tons of pyrite per annum. The present production is very small. The possibility of furnishing the domestic trade with pyrites recovered as a byproduct from coal-mining operations appears attractive but there are certain features difficult to overcome. Pyrite, to be used in acid making, must meet with certain requirements as to size and purity. Lump ore for grate burners should be under 3 in. (7.6 cm.) and over 1 in. (2.5 cm.) in diameter. Fines for use in mecnanical roasters should be under quarter mesh. The material should be high in sulfur, free from arsenic and phosphorus, and as low in carbon as possible. The pyrite obtained from coal can be made to meet all the above requirements, but it is difficult to remove all the carbon. The pyrite in coal occurs as bands and nodules of varying thickness and size and of comparative purity, but mixed with this is more or less web sulfur. The web sulfur carries with it admixed coal, which may make the concen-

Jan 8, 1919

In the Bowen Basin of central Queensland, coal production has gone from virtually nothing in 1961 to more than 24 million tons today4ut there's a cloud over this success.

Jan 1, 1977

By George C. Gibbons

ALMOST everyone in any of the five counties embracing the great East Texas field depends heavily upon oil for his living whether or not he actually owns a well or piece of royalty himself. Oil is a natural resource that, when utilized, spreads its benefits over a vast area and into many channels. Depending then almost entirely upon agriculture: what is now known as the East Texas oil field a decade ago had a scattered farming population. For many of its people, tomatoes and other vegetable crops coupled with the old southern stand-by of cotton, furnished an adequate living and a small cash surplus. Some farm families on the red hills, however, were not far re- moved from the sowbelly and black- eyed peas, or cornpone and potlikker, standard of living. Kilgore of that day, was a village of less than 850 per- sons. Longview, with just over 5000, apparently had reached the limit of its growth. Tyler was an overgrown farming town of around 17,000 persons, de- pending largely upon the agricultural income of Smith County and surrounding territory for which it was a trading center.

Jan 1, 1941

By A. T. Yu

Over the last 80 years the conveyor belt has advanced from the troughed rubber belt to those with standard steel cable cores and those which can navigate curves or climb steep inclines. Now the latest generation of belt conveyors can claim hitherto unheard of capacities of 20,000 tph and single flight lengths well exceeding 16,000 feet. The stranded steel cable core belt is principally responsible for the spectacular improvement in load carrying ability of belt conveyors. The allowable working tension of these belts ranges from 2,500 lb per in. of belt width for 1/4 in. diam cable to 4,000 lb per in, for 3/8 in. diam cable. These ratings far exceed the 240 lb per in. per ply for rayon or nylon construction, and 30 lb per in. per ply for a lowcost cotton fabric.

Jan 1, 1970

By R. S. Dean

IN THE COURSE of its investigations directed toward providing strategic metals from domestic sources and toward utilizing power from Federal power projects in West, the Bureau of Mines concluded some years ago that the development of a method for producing electrolytic manganese might well be an important step towards both goals. Accordingly, laboratory investigations were undertaken in 1935. Further studied on a relatively large laboratory scale indicated that electrolytic manganese could be made from domestic ores at a cost not out of line with other nonferrous metals. On the basis of these results, the Electro Manganese Corp. Operating under U.S. Patent 2,119,560 issued to S, M, Shelton and assigned to the Secretary of the Interior for administration, undertook commercial production of electrolytic manganese at Knoxville, Tenn, This company has brought the process through the pilot-plant stage successfully, and is now regularly producing approximately one ton a day.

Jan 1, 1941

By GUY B. HUNNER

THOSE magnetite ore bodies comprising the Clifton Mines are situated in the south central part of St. Lawrence County, New York, on the western slope of the Adirondack Mountains. The topography is made up of gently rolling hills densely wooded with second-growth maple, birch, and hemlock. Drainage is north and west to the St. Lawrence River.

Jan 1, 1943

By H. T. Shore, J. M. Schultz

A number of experimental rnethods—X-ray powder diffractometry, Laue photography, X-ray small-angle scattering, and transmission electron microscopy and dijfraction—have been utilized to examine the morphology associated with precipitation from the terminal, g, solid solution of a Zn-1 pct Cu alloy. A significant age hardening was observed in a 1 pct Cu alloy. X-ray and electron diffraction results showed that the structural inhomogeneities associated with the hardening were isotructural with the matrix. The average size and shape of the inhomogeneities were deduced from the electron microscopy and X-ray small-angle scattering. The preprecipitates are hexagonal platelets some 300? in diam. and some twelve unit cells thick. The orientation of the platelets was deduced from Laue photographs and electron diffraction. The platelet plane is (0001). When a large amount of pre-precipitation is present in a localized volume the new lattice is often disoriented by a rotation about (0001) of of the matrix. WhILE dilute Zn-Cu alloys have been commercially important for some 50 years, relatively very little is known metallographically about this material. The "Zilloys", zinc with about 1 wt pct Cu and sometimes a small addition of magnesium, are used to produce rolled zinc which is harder and stronger than that produced by other rollable zinc alloys.' According to the phase diagrams of the zinc-rich side of the Cu-Zn system, such dilute Zn-Cu alloys should age-harden;2-5 the solubility of copper in zinc, g-phase, at 424°C is 2.68 pct, while at 0°C it is only to 0.3 pct. However, the published literature on the aging of this system appears to be limited to a documentation of the contraction of 1, 2, and 3 pct Cu alloys aging at 95°c,6 and an attempt to measure changes in lattice parameters during aging.' In the latter work, no lattice parameter changes were detected, although a broadening of the highest-angle lines was detected and considerable diffuse scattering was observed. Micro-structural investigations have been limited to the latest stage of aging, wherein Widmanstatten precipitates are formed.3,47 These alloys are of interest for still another reason. The two most zinc-rich phases in the Cu-Zn system, 77 and E, are both hcp. Moreover, the change in a, between 17 and t for a 1 wt pct Cu alloy is onlv 3.64 -,~ct: the change in Co is 12.0 ict. It would be anticipated that precipitation in such a material might occur through metastable phases or G.P. zones with epitaxy along mutual 0001 planes. The goals of the present work are aimed at partially filling the void of knowledge concerning the early stages of precipitation from the g phase. In particular, we have attempted to document the magnitude of the age hardening of this system and to determine the size, shape, and orientation within the matrix of the elements of precipitation in an early stage of condensation. EXPERIMENTAL A) Specimen Preparation. Specimens were prepared In two somewhat different ways, one method being used for X-ray Laue and diffractometer measurements, optical microscopy, and Rockwell hardness measurements and the other used for electron microscopy and X-ray small-angle scattering. In the first case zinc and copper in the proper proportions to yield a 1 wt pct Cu alloy were melted together in a closed graphite crucible. Castings so made were free of apparent segregation or oxidation. The castings were then solution-annealed at 400°C for several days and then quenched in water to room temperature. Filings of portions of the specimens were made for use as X-ray powder diffractometry specimens. The electron microscope material was made as follows. Castings were made under vacuum with copper powder placed inside a hollow zinc cylinder to insure good contact of the materials. These 1 wt pct Cu pieces were then rolled to 0.1 mm with an intermediate anneal in vacuo. The rolled sheets so formed were then annealed for about 6 hr at 225°C. Finally the specimens were electropolished slowly until thin enough for transmission electron microscopy. The polishing is discussed in greater detail in the Results section. B) Measurements. X-ray measurements of three types were performed. A G.E. XRD-5 diffractometer was used to examine powders of the alloy for identification of second-phase material. A Kratky small-angle camera, also operating from a G.E. tube, was used to investigate the sizes of small precipitate particles. In both cases, nickel-filtered copper radiation was utilized. Finally, individual grains of the large-grained castings were examined in the back-reflection Laue geometry. Electron microscope studies were carried out with a J.E.O.L. Model 6A instrument. RESULTS A) Hardness Measurements. Hardness measurements performed at room temperature on the large-grained polycrystalline specimens showed a hardening which was essentially complete in 3 hr. Fig. 1 shows a typical plot of hardness vs aging time. The relative magnitude of the ultimate hardening varied from run to run between 150 and 200 pct of the value for the material immediately after quenching from the solution anneal. Most probably the variations reflect small changes in the time taken to remove the specimen from the vacuum furnace after the solution anneal.

Jan 1, 1969

Alexander Forsyth, Southport, Me. (communication to the Secretary): In Mr. Irving's able and interesting paper he describes minutely the appearance of the wolframite and its association with the refractory siliceous gold-ore. He also describes this gold-ore, but fails to mention the important pockets of metallic gold found in the Lead City occurrence of it. I use the term " metallic " in preference to the more usual " free," for it has been found that this gold is not easily amalgamated. Metallic gold is comparatively rare in the refractory siliceous gold-ores of the Black Hills; hence its occurrence in considerable amounts in the Lead City wolframite district deserves notice. I possess a beautiful specimen from the Harrison mine. It is a lump of drusy, granular ore, about 6 in. in diameter. The gold .is " shot" through it in large and small pin-heads; and in two specially oxidized areas, each about 11/2 in. in diameter, it is peppered full. The famous " Grantz strike," made in the Lead City wolframite locality, produced many beautiful gold specimens. This district affords an excellent example of the repeated discovery of new mineral values upon old ground. By reason of its proximity to the Homestake vein, this wolframite deposit was inevitably traversed many times by experienced geologists, mineralogists and mining engineers, who evidently must have thrown aside, with no thought of wolframite, the lumps of " black iron " lying about. I have the admission of an able geologist that, six months before the wolframite was discovered, he visited some of the very mines where it occurred, and passed it by as magnetic iron-ore. At the time of the discovery, the mineral was scattered over the gold-mine dumps in no small quantities, having been culled as worthless out of the gold-ore. It remained for

Jan 1, 1902

By Ralph M. Hunter

Until recent years, maintenance of surface coal handling facilities was a relatively simple task. Equipment consisted principally of conveyors, screens and crushers of comparatively simple construction. Electrical equipment consisted of motors and starters, with little, if any, interlocking. In most cases failure of any component affected only the grades of coal loaded so that even a prolonged breakdown did not affect mine operation materially. However, with the introduction of modern cleaning plants, the picture has changed. The equipment is much more complex and therefore more difficult to maintain. In many cases failure of any component of the plant prevents loading of coal. Even if provision is made to bypass, the quality of coal loaded is lowered, affecting markets. In the case of plants designed to permit full seam mining, marketable coal cannot be loaded without operation of the cleaning plant. Under these conditions it is apparent that considerable thought and effort toward better maintenance are justified. In order to assure continuous, efficient and economical operation, maintenance should receive consideration, not only after the plant is in operation, but while it is being designed. It is hardly necessary to say that the designer should strive for sturdi-ness and wearing qualities. It is sometimes not realized, however, that even the best parts will sooner or later require replacement or repair. The designer should, there- fore, give consideration to accessibility. Anyone who has had to do with cleaning plant maintenance is familiar with installations where several hours are required to get at a part that can be repaired or replaced in a few minutes, once it is accessible. As in most cases, experience is the best guide. The men who operate and maintain this equipment know the problems encountered. Whenever available, the opinions of these men should be sought and heeded. As an example, we might consider the refuse elevator on a Chance Cone. Our company is now operating three of these cones, the first of which was installed in 1941, and the latest in 1946. Exact records are not available, but well over 50 pct of delays charged to the Chance Cones have been caused by the refuse elevator. This elevator receives refuse from the cone and carries it to a point above the water level of the cone, discharging onto a dewatering and desanding screen. Since the elevator operates under water and necessarily has close clearances in the lower boot, it tends to jam on large pieces of refuse or tramp iron. The chain, buckets and boot are also subjected to the action of water, sand and refuse, which accelerate normal wear. In case of jamming or chain-breakage it is necessary to drain the elevator and the cone so that even a minor fault in the elevator causes a considerable loss of time for the cone. In our new plant, which will contain two Chance Cones, the refuse elevator has been eliminated. This was accomplished by raising the cone so that the refuse gates could discharge directly onto the dewater-

Jan 1, 1949