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By Nicholas T. Camicia

Coal is one of our oldest known commodities. Historic evidence indicates that this fossil-formed fuel was used in China and in Wales some 3000 to 4000 pears ago. Coal was discovered in North America in 1679 by French explorers in northern Illinois, and in 1700 a colony of Huguenots came across bituminous coal in Virginia. One might think by this long history of a single commodity that the string was about played out. Quite the contrary, coal is in greater demand than ever before and coal mining today is a modern industry. It is in an unprecedented growth period as the nation-and the world-demands more and more energy coincident with dwindling reserves of other fossil fuels. By the year 2000 the demand for coal is expected to at least double the current level of some 600 million tons annually despite the advent of nuclear power. To meet this challenge, the coal industry is vitally in need of an increasing supply of technically trained and progressive manpower. And, coupled with a serious shortage of engineers and technicians, it represents a rich vein of occupation opportunities-all the way up to top career levels. Today, coal mining is a complex, highly specialized industry concerned with more than just getting coal from the earth and putting it into the furnaces of the consumer. The industry is concerned with the environment, with maintaining a viable ecology. Recognizing the ramifications of global economics, the industry is very much aware of its important position in contributing to a constantly rising standard of living throughout the world. The key to rewarding employment in the coal industry is skill-skill that has been developed by education, training, and experience. None of these alone is enough; all three are necessary today to produce the skill needed to meet the employment requirements of the coal industry. Routine manual labor will no longer do the job in coal mining. In the United States coal mining has been mechanized to a degree unsurpassed anywhere else in the world, and the coal worker must be thoroughly

Jan 1, 1973

By Walter Miller

The broad picture of petroleum refining engineering during 1934 continued to show a tendency in the direction of highly specialized processing improvements, particularly in manufacture of lubricating oil. The slowing up of the trend toward higher octane products in non-premium gasoline noticed in 1933 was definitely established as a fact by 1934 development, with just a slight indication of recession. No outstanding engineering achievements can be credited to 1934 in refinery cracking, unless the completion and successful operation of the 30,000-bbl. crude capacity combination cracking and skimming unit at Texas City, Texas, and a 20,000-bbl. similar unit in the East can be listed as such. Development and improvement was largely a continuation of previous lines of endeavor. Such trend as there is shows a continnation in the direction of very large integrated skimming and cracking units. A lessening of the cost of ethyl lead, coupled with the reaching of the octane number "ceiling," kept the subject of "reforming" low-octane gasoline into high-octane products pretty well in the background. Considerable interest, however, was shown during the year in cracking and polymerizing of refinery gases into high-octane motor fuel. The commercial development and application of this activity was greater in 1934 than during any previous year. Fair yields of gasoline of satisfactory stability and high antiknock value were reported, ranging from 2 to 8 gal. per 1000 cu. ft. of fixed refinery gas, yields varying with both the nature of refinery gas treated and processing methods. Assuming economic feasibility, regarding which there is still difference of opinion, gas polymerization offers the industry a possible outlet for its gases more in keeping with its basic chemical composition and value. The increased interest of railroads and heavy-duty truck and tractor manufacturers served to focus more attention on diesel fuels. The publicity given the Union Pacific diesel train, the Burlington "Zephyr" and others operated on special diesel fuels served to revive the intimations and fears of several years ago as to the ultimate replacement of the gasoline motor by diesel engines in even the passenger car field. How-

Jan 1, 1935

T. R. HARRISON, Washington, D. C. (written discussion). *-Mr. Kowalke shows that a high resistance millivoltmeter is subject to smaller errors, due to change in resistance of the thermocouple to which it is attached, than is a low-resistance instrument. He uses as examples instruments having resistances of 30 and 2 ohms, respectively. At the Bureau of Standards, resistances above 300 ohms would be considered high and 30 ohms rather low. In the tests on calorized-iron thermocouples, a difference between the first and third calibrations of the couples serves to show changes due to the intermediate heat treatment and only under certain conditions would changes in calibrations due to changes in the wire be detected by ,a recalibration after 1 1/2 in. had been cut from the hot-junction end of the couple and the ends rewelded. The calibration of a couple depends only on the thermoelectric prop-erties of that part of the couple which lies within the region of non-uniform temperature, i.e., the temperature gradient; hence, so long as the temperature gradient falls along wires of similar thermoelectric properties no change in the electromotive force is produced by altering the metals of those parts of the circuit that are at uniform temperature. Usually at the cold-junction end of the circuit, copper leads, brass binding posts, manganin resistance coils, and various other materials form part of the circuit, but so long as all are at a uniform temperature (or if for each junction between unlike metals there is a similar opposing junction at the same temperature) no resultant thermoelectromotive force will be produced thereby. Likewise, if a length of several inches at the hot-junction end of the couple is at uniform temperature, it matters not if this section is unlike other parts of the couple, so long as there is good metallic connection and no source of e.m.f. other than thermoelectric is present. Cutting off part of the hot end of the couple within such a region of uni-form temperature would not alter the e.m.f. of the couple.

Jan 12, 1919

By Joseph C. Kieffer

The Duquesne property of the Callahan Zinc-Lead Co. is about 20 miles east of Nogales, in southern Arizona. One mine is near the mill, but most of the mill feed is hauled in by truck from a number of small mines. The same sulphides are found in all the ores, in general, but the amounts vary considerably. All ores contain silver, copper, lead and zinc minerals but one mine ships ore high in silver and lead and low in copper and zinc; while another mine ships ore high in copper and zinc, and low in silver and lead. The common sulphides are galena, carrying most of the silver; chalcopyrite; sphalerite, carrying iron in solid solution; and pyrite, in a gangue consisting of limestone, quartz and garnet. Mineralization is fairly coarse. At the present grind of about 66 per cent minus 200 mesh most of the sulphides are liberated A small amount of chalcopyrite is locked up with the sphalerite and cannot be liberated at an economic grind, and the copper carried into the zinc concentrate with the sphalerite accounts for the comparatively poor recovery of copper in the copper-lead concentrate. Production oF Two Concentrates The milling problem, which was complicated by the extreme variation in the grade of the feed, was first attacked with the idea of producing a silver-copper-lead con- centrate and a zinc concentrate, both with satisfactory grades and recoveries. By February 1941, it was felt that these objectives had been attained, when the grades of the various products and the recoveries were as shown in Table I. A rough outline of the flowsheet and reagents used is as follows: Minus ¾-in. feed to a 7-ft. by 36-in. Hardinge ball mill working in closed circuit with a 36-in. Wemco classifier. The classifier overflow passes to the second cell of an 8-cell bank of No. 18 Special Denver Sub-A flotation machines (volume, 22.5 cu. ft. per cell). A rougher concentrate is removed from the second to the fifth cells inclusive, and returned to the first cell, which is the cleaner. A scavenger concentrate is removed from the sixth, seventh, and eighth cells, and returned to the third cell. Consump-

Jan 1, 1943

By D. J. Mottern, F. Wald

SEVERAL systems have been investigated by Bates, Wald, and weinstein&apos; to determine the compatibility of pure PbTe with various metals. This was accomplished by experimentally determining the direction of the reaction given by Eq. [I]: The direction of this reaction is very important if alloys of the PbTe system are to be used in thermoelectric generators because the presence of free lead in the matrix, followed by incipient melting in the vicinity of the hot junction, could cause a bonding failure. According to anssen,&apos; the Au-Te system contains only one stable compound, AuTez. The initial alloy which was reacted was therefore of the composition AuTez + 2Pb. Ten-gram samples of PbTe plus 1, 10, 20, 30, 40, 50, and 70 at. pct Au were encapsulated in carbon-coated quartz capsules in vacuo. All materials were of semiconductor (99.999+ pct) purity. Carbon coating was used to prevent reaction of the quartz with any of the alloying constituents (the solubility of carbon in the constituents of the alloys is negligible). Each capsule was then placed in a thermal analysis furnace, melted, and cooled through the transformation region. Thermal arrests were monitored on a strip chart recorder. Each sample was subsequently examined microscopically after standard grinding and polishing techniques were applied. For better contrast between the phases, the samples were etched in Murakami&apos;s etch; however, both phases could be identified without etching. Several of the samples were ground into powder, stress-relieved, and X-rayed in a Debye-Scherrer camera using nickel-filtered Cu-Ka radiation. The phase diagram shown in Fig. 1 indicates that the pseudobinary system exists as a simple eutectic with no measurable (<I pct) solid solubility at either limit. Figs. 2,3, and 4 are photomicrographs of the structures obtained with 20, 40, and 50 at. pct Au, respectively. At higher concentrations of gold (>40 pct) slight divorcement of the eutectic occurred, apparently due to a) the difference in density between gold and PbTe (19.6 and 8.25 g per cu cm, respectively) or b) the nonideality of the liquid as noted by the curvature of the liquidus lines. The eutectic temperature was determined to be 742° ± 5°C. The composition of the eutectic was determined by extrapola-

Jan 1, 1969

By George W. Sheary

Situated 45 miles west of Philadelphia and 50 miles southwest of Bethlehem Steel Company&apos;s Bethlehem plant, the integrated Grace mine facilities produce 4000 tpd of high-quality iron ore pellets. Startup of the Grace mill was in November 1958, and iron concentrates were shipped until March 1960, when the pellet plant went into operation. The underground mine, when fully developed, will hoist about 9000 tpd, including development rock. The crude ore, which has an iron content of approximately 42%, is magnetically cobbed and crushed in closed circuit with 3/4-in. slotted vibrating screens. The ore is washed and screened in the mill and the plus 1/4 in. screen product is again cobbed prior to feeding to the rod mills. Grinding is done in rod mills, and in ball mills that are in closed circuit with 30 in, cyclones, to 1% on 100 mesh and 65% minus 325 mesh. The ground ore is magnetically concentrated by three-drum permanent type finisher magnets to 67% Fe. The magnetite concentrate is pumped from the mill to a 50 ft thickener in the pellet plant. The thickened magnetite concentrate is relayed to the filters through a two-stage pump arrangement. The filter cake is fed by belt from filter concentrate bins to mixer-muller belts where it is intimately mixed with bentonite and a slight amount of water for moisture control. The fluffed concentrate then drops into balling cones. The green pellets from the balling cones are fed in a prescribed feed pattern to shaft furnaces through the use of shuttle car mechanisms. The green pellets are dried, heated to 2500°F and cooled to 1200°F as they descend through the furnace and into pellet coolers where the pellets are further reduced in temperature to 250°F. Heat is recovered in the cooling process through the use of air-to-air heat exchangers. The cooled pellets discharge on a rubber conveyor belt and are transferred to 6000-ton pellet railroad loading bin. The final pellet product consists of 90% plus 1/4 in. material (after tumble testing1) and contains 66% Fe plus 3% silica.

Jan 5, 1962

By S. W. Hurlbut

12.4 Application of Research Findings. After the findings of research have been evaluated and approved, there remains the problem of translating them into practical usage. It frequently happens that this is the more difficult phase of the research project. Hitherto, the problems have been largely associated with material objects and scientific laws. When the findings of research are implemented in the field, the human factor becomes the most important element bearing on success or failure. From this point on, the attitudes and reactions of people of all kinds are involved, and just how they are involved and their relation to successful implementation is the subject of the remainder of this section. 12.41. Management Attitudes. To engage in research at all implies management backing to a degree. But this could be dictated by overall company policy or by just some executives in the hierarchy of management. The existence of research per se does not necessarily mean that there is a solid, unanimous echelon of management executives who sincerely believe in the fruits of research, who have an earnest desire to make breakthroughs, and who have a willingness to take calculated risks. Under the ideal condition of complete management backing, translating the results of research into practice is greatly facilitated. If management accepts the results of research as valid, the order is given, or it has been established by precedent that those results will be implemented. The rest of the organization will have grown to accept the fact that this is so, and that the results must be given a fair trial in the field. However, this ideal condition probably exists but rarely, and it is against a background of incomplete, or partial, management backing that most results of research must be implemented. At the present time, the climate for research in the mining field is less than perfect but is improving rapidly as the realization grows within the industry that the way toward taking its proper place in the Space Age is by applying to mining the philosophy and techniques of research that made the Space Age possible.

Jan 1, 1968

By Euzebio P. de Oliveira

One of a recent batch of samplcs from the Serra da Baliza, in the state of Paraná, Brazil, contained asphalt and a dark heavy oil; and workmen on the railway from Porto Uniáo to Uruguay discovered asphalt coming from eruptives that outcrop along the Rio de Peixe. The occurrence of asphalt in the triassic eruptives of southern Brazil, however, has been known a long time, according to Dr. Gonzaga de Campos. It is generally believed that the Botucatd sandstone is always a hard vitrified rock, from the metamorphic action of the overflowing eruptive contacts. In this region, howeyer, the contact metamorphism is almost nil; the sandstone is slightly hardened in a narrow zone about 20 to 30 cm. wide. In many places, the sandstone is so friable as to be easily reduced to sand, which is used in mortar for building in Guara-puava and Palmas. South and west from Porto Uniáo, this bench of sandstone is about 50 m. thick, and is capped by a heavy bed of basic eruptives, many of which are amygdaloids. Nature of Rocks Dr. Geo. P. Merrill, after studying the triassic eruptives collected by the Coal Commission, reached the conclusion that "All these rocks are of typical basalt-diabases, not in any essential different other than in structure. An interesting mineralogical phase is its paucity in olivine, which in many cases is completely lacking." Professor Hussak, who carefully studied these rocks and their accessory minerals, decided that in the dikes they are granular (diabase) and that in the lava sheets, porphyritic (augite-porphyrite or melaphyre), and that the latter pass evidently to normal diabases and are always typical of effusive rocks. The examination of many slides from dikes and sheets leads us to adopt the opinion of Professor Hussak; the rocks of the dikes are of ophitic structure, while that of the sheets show a great variety of structure and may vary from almost granular to basaltic. The great paucity in olivine had been noted by Hussak, who classes as melaphyres, the porphyritic triassic rocks in Brazil which contain olivine.

Jan 1, 1921

By Thomas Read

READJUSTMENT Of the industrial world to a peace .basis after more than 4 years of war will involve many fundamental and far-reaching changes that cannot as yet he clearly foreseen or definitely provided for. Such problems may be subdivided, in the vocabulary of war, into those involving material and those centering about personnel. Of the two, the-latter group is the more difficult and obscure, as the factors involved are less clearly understood and the methods to be followed are not yet tested and standardized. When it is said that the market is weak, stocks large, and demand light, every business man understands clearly what is meant and. what course he should adopt to adjust himself, so far as possible, to such conditions. But when it is said that the rapid spread of Bolshevism in Europe is a danger to industrial organization in this country, it is difficult to have any assured sense that all that the statement may mean is clearly understood or that the means to be followed to meet such a situation are definitely known. Since Bolshevism is primarily a mental phenomenon and since the rupture it brings about in industrial organization should be prevented, if possible, it is my purpose to restrict this discussion of the activities of the Committee on Industrial Organization to some of its mental aspects, as the chairmen of the sub-committees, from their special knowledge of their own fields, can best set forth recent progress in the lines with which they are especially concerned. The first requisites of success in industrial organization, as in the biological organism of which it is the social counterpart, are unity of purpose and coordinated activity. Typical good and bad examples of this are the relative parts that the United States and Russia have played in the great war. These two factors are primarily mental, and it is not difficult to view the mental aspects of all problems of industrial organization as the most important ones. Unless we can attain unity of purpose and coordinated activity in industry, the provision of comfortable homes at reasonable rent, the assurance of steady work at good wages, the

Jan 2, 1919

By Joseph C. Kieffer

The Duquesne property of the Callahan Zinc-Lead Co. is about 20 miles east of Nogales, in southern Arizona. One mine is near the mill, but most of the mill feed is hauled in by truck from a number of small mines. The same sulphides are found in all the ores, in general, but the amounts vary considerably. All ores contain silver, copper, lead and zinc minerals but one mine ships ore high in silver and lead and low in copper and zinc; while another mine ships ore high in copper and zinc, and low in silver and lead. The common sulphides are galena, carrying most of the silver; chalcopyrite; sphalerite, carrying iron in solid solution; and pyrite, in a gangue consisting of limestone, quartz and garnet. Mineralization is fairly coarse. At the present grind of about 66 per cent minus 200 mesh most of the sulphides are liberated A small amount of chalcopyrite is locked up with the sphalerite and cannot be liberated at an economic grind, and the copper carried into the zinc concentrate with the sphalerite accounts for the comparatively poor recovery of copper in the copper-lead concentrate. Production oF Two Concentrates The milling problem, which was complicated by the extreme variation in the grade of the feed, was first attacked with the idea of producing a silver-copper-lead con- centrate and a zinc concentrate, both with satisfactory grades and recoveries. By February 1941, it was felt that these objectives had been attained, when the grades of the various products and the recoveries were as shown in Table I. A rough outline of the flowsheet and reagents used is as follows: Minus ¾-in. feed to a 7-ft. by 36-in. Hardinge ball mill working in closed circuit with a 36-in. Wemco classifier. The classifier overflow passes to the second cell of an 8-cell bank of No. 18 Special Denver Sub-A flotation machines (volume, 22.5 cu. ft. per cell). A rougher concentrate is removed from the second to the fifth cells inclusive, and returned to the first cell, which is the cleaner. A scavenger concentrate is removed from the sixth, seventh, and eighth cells, and returned to the third cell. Consump-

Jan 1, 1943

By Joseph C. Kieffer

THE Duquesne property of the Callahan Zinc-Lead Co. is about 20 miles east of Nogales, in southern Arizona. One mine is near the mill, but most of the mill feed is hauled in by truck from a number of small mines. The same sulphides are found in all the ores, in general, but the amounts vary considerably. All ores contain silver, copper, lead and zinc minerals but one mine ships ore high in silver and lead and low in copper and zinc; while another mine ships ore high in copper and zinc, and low in silver and lead. The common sulphides are galena, carrying most of the silver; chalcopyrite; sphalerite, carrying iron in solid solution; and pyrite, in a gangue consisting of limestone, quartz and garnet. Mineralization, is fairly coarse. At the present grind of about 66 per cent minus 200 mesh most of the sulphides are liberated. A small amount of chalcopyrite is locked up with the sphalerite and cannot be liberated at an economic grind, and the copper carried into the zinc concentrate with the sphalerite accounts for the comparatively poor recovery of copper in the copper-lead concentrate. PRODUCTION OF TWO CONCENTRATES The milling problem, which was complicated by the extreme variation in the grade of the feed, was first attacked with the idea of producing a silver-copper-lead concentrate and a zinc concentrate, both with satisfactory grades and recoveries. By February 194I, it was felt that these objectives had been attained, when the grades of the various products and the recoveries were as shown in Table I. [ ] A rough outline of the flowsheet and reagents used is as follows: Minus ¾ -in. feed to a 7-ft. by 36-in. Hardinge ball mill working in closed circuit with a 36-in. Wemco classifier. The classifier overflow passes to the second cell of an 8-cell bank of No. I8 Special Denver Sub-A flotation machines (volume, 22.5 cu. ft. per cell). A rougher concentrate is removed from the second to the fifth cells inclusive, and returned to the first cell, which is the cleaner. A scavenger concentrate is removed from the sixth, seventh, and eighth cells, and returned to the third cell. Consump-

Jan 1, 1942

By William Blauvelt

THE type of gas producer in which the ashes are fluxed and run off as slag was among the very earliest made. Ebelmen built the first one in 1840 at Audincourt, France, only a year after the installation of the first gas producer of which we have record. Charcoal was used as the fuel, with blast-furnace slag and clay is flux. My interest in this type of producer began when as a boy I saw the fluxing producer at Chester, N. J., which was invented by W. J.. Taylor, and described by him in 1881.1 This producer was invented independently by Mr. Taylor to meet the difficulties he experienced in making producer gas for roasting sulphurous iron ores. It will be of interest to review briefly his description of his producer. It was built like a small blast furnace, having a hearth 24 in. in diameter and 24 in. high. The bosh angle was 25° from the vertical; the diameter at the bosh 4 ft. and at the top 3 ft.; the total height 12 ft. The producer contained one water-cooled tuyere 12 in. above the bottom, with a 1.5-in. nozzle.. Depth of the coal above the tuyere; 6 ft. Mr. Taylor mixed the coal with from 30 to 40 per cent. of basic blast-furnace slag to flux the ash. Occasionally some limestone was also used, but never limestone alone, as the use of the furnace cinder gave a larger volume of slag and made it easier to maintain a proper fluidity. . The producer was blown with a small Weimer blowing engine, delivering 300 ft. of air per minute, at from 1 to 1.5 lb. pressure. The slag was tapped every 2 hr. and was black and glassy in appearance. Broken or egg size anthracite was used. The fine sizes of anthracite could not he made to work. Mr. Taylor expressed the belief that bituminous coal could be used if not too fine, but no experiments were made with this coal. Runs were made of four weeks&apos; duration, with no stops or changes. Mr. Taylor reported the following advantages:

Jan 12, 1913

By H. M. Boylston

Metallic manganese was first produced in 1773, by Sven Rinmann, a Swedish mineralogist. In 1799, William Reynolds, of Ketley, England, obtained a patent on the use of manganese dioxide in the manufacture of steel, and in 1808 an English patent was granted to John Wilkinson covering the use of manganese ore, or manganiferous ore, as an addition to iron ore in the blast furnace for the production of a superior grade of pig iron. Karsten showed in 1816 that manganese increased the hardness of iron without decreasing its malleability or toughness, while it caused pig iron to be more white in fracture and more fusible. The first practical application of manganese to steel-making, however, is attributed to Josiah Heath who discovered in 1839 (less than 90 years ago) that manganese conferred upon steel the properties of being more easily worked and welded under the hammer. When Bessemer invented the pneumatic process of steel-making which now bears his name he was at first successful because, as it afterward developed, he was using a Swedish pig iron high in manganese. When his supply of this material ran out, he used a low-manganese pig from English sources and failed signally to produce a steel which could be rolled, while his Swedish licensees were continuing their successful application of his method. And it was not until Robert Mushet, in 1856, suggested the addition of manganese in the form of spiegeleisen to the molten product of the converter that success again came to Bessemer. In 1866, William Siemens patented the use of ferromanganese as an addition to molten steel to counteract the bad effects of sulfur. It was in 1888 that Robert Hadfield published at some length his account of the effect of manganese as an alloying element in steel and described the unique properties of the now famous Hadfield manganese steel containing about 12 to 14 per cent. manganese and 1.25 per cent. carbon. Function or Manganese in Steel-making Bessemer&apos;s failure at one period of his experimental work to make steel which could be forged successfully was due to the fact that the

Jan 1, 1927

By H. E. Doerr

THE writer has been unable to find much information relative to tests made to determine the effect of forging on the specific density of steel. The opinion, however, among men engaged in the business, seems to he that forging greatly compresses or consolidates the steel. While such is doubtless the case with spongy or porous steel, the following experiments indicate that there can be little or no change in the density with steel initially free from cavities: Ten ingots of basic open-hearth steel cast as shown in Fig. 1 were used in the experiments. All the specimens were 0.53 carbon with all other elements the same, the analysis being determined from drillings taken midway between the center and outside of the upper end, as shown in Fig. 2. The specimens were selected from over one thousand ingots so that the tests could be comparative for the work done in forging only, but no two of the ingots were cast in the same heat. Each ingot remained in the mold approximately 30 min., when it was removed and air-cooled. About 12 hr. later, when the temperature had been reduced to approximately that of the surrounding atmosphere, the head was discarded and the ingot heated in an oil furnace to approximately 2250° F. (1235° C). Approximately 1 min. was required to forge under the steam hammier to 1 ¼ in. (31.75 mm.), rough diameter, as shown by the dotted lines in Fig. 2. All ingots were allowed to air-cool after forging. Cylinders ½ in. (17.7 mm.) in diameter and ½ in. high were then turned from the forged and unforged parts of the ingots and numbered. The ten pairs of specimens were submitted to Louis E. Endsley, Professor of Railway Mechanical Engineering, University of Pittsburgh; A. N. Talbot, Professor of Applied Mechanics, University of Illinois; L. Z. Slater, chief chemist, Scullin Steel Co., St. Louis, Mo. No in-formation was furnished as to which specimens were forged or unforged and each laboratory used the same specimens, submitting the average of three independent determinations, a tabulation of which is shown in the accompanying table in which the laboratories are designated by

Jan 1, 1919

By T. R. Armstrong

During the year 1939, Mexican production totaled 42,479,000 bbl.; a daily average of 116,381 bbl. or a little over 2 per cent of the estimated world production. The Mexican Government operates 100 per cent of the refining branch of the industry, 100 per cent of the domestic distribution, 96 per cent of the crude production and 92 per cent of the total exports. No discussion of the Mexican petroleum industry in 1939 is adequate without reference to the "expropriation" of the foreign-owned oil properties in Mexico by executive fiat on March 18, 1938. The forcible seizing of the properties culminated a long series of efforts on the part of the Mexican Government to obtain control of the oil properties developed through foreign initiative and with foreign capital in Mexico. The heart of the issue is whether the Mexican nation or any nation may with impunity confiscate the legally acquired properties of American citizens. The Department of State of our Government has in its communications to Mexico emphasized the fact that its "expropriation" of American properties was confiscatory because Mexico had failed to make "adequate, effective and prompt compensation"; that the taking was no less confiscatory "because there may be an expressed intent to pay at some time in the future," and that, consequently, "Mexico has assumed and continues to assume to exercise a right without compliance with the condition necessary to give such exercise a recognizable status of legality." Mexico has professed its willingness to pay for the oil properties but at the same time through its Supreme Court it has declared that the owners or lessees do not have the exclusive right to extract and dispose of the oil in the subsoil. This is a reversal of the Mexican position with respect to oil as set forth in the Mexican mining laws, affirmed by Mexican Supreme Court decisions, and as clarified in the Warren-Paync and the Morrow-Calles agreements, as well as in diplomatic correspondence. Efforts to Settle the Controversy Responding to suggestions from the State Department, representatives of the principal oil companies undertook in 1939 to effect a direct

Jan 1, 1940

By Joseph C. Kieffer

THE Duquesne property of the Callahan Zinc-Lead Co. is about 20 miles east of Nogales, in southern Arizona. One mine is near the mill, but most of the mill feed is hauled in by truck from a number of small mines. The same sulphides are found in all the ores, in general, but the amounts vary considerably. All ores contain silver, copper, lead and zinc minerals but one mine ships ore high in silver and lead and low in copper and zinc; while another mine ships ore high in copper and zinc, and low in silver and lead. The common sulphides are galena, carrying most of the silver; chalcopyrite; sphalerite, carrying iron in solid solution; and pyrite, in a gangue consisting of limestone, quartz and garnet. Mineralization is fairly coarse. At the present grind of about 66 per cent minus 200 mesh most of the sulphides are liberated. A small amount of chalcopyrite is locked up with the sphalerite and cannot be liberated at an economic grind, and the copper carried into the zinc concentrate with the sphalerite accounts for the comparatively poor recovery of copper in the copper-lead concentrate. PRODUCTION OF TWO CONCENTRATES The milling problem, which was complicated by the extreme variation in the grade of the feed, was first attacked with the idea of producing a silver-copper-lead concentrate and a zinc concentrate, both with satisfactory grades and recoveries. By February I94I, it was felt that these objectives had been attained, when the grades of the various products and the recoveries were as shown in Table I. [ ] A rough outline of the flowsheet and reagents used is as follows: Minus ¾ -in. feed to a 7-ft. by 36-in. Hardinge ball mill working in closed circuit with a 36-in. Wemco classifier. The classifier overflow passes to the second cell of an 8-cell bank of No. 18 Special Denver Sub-A flotation machines (volume, 22.5 cu. ft. per cell). A rougher concentrate is removed from the second to the fifth cells inclusive, and returned to the first cell, which is the cleaner. A scavenger concentrate is removed from the sixth, seventh, and eighth cells, and returned to the third cell. Consump

Jan 1, 1942

Jerome L. Boyer, Reading, Chairman; William L. Sheafer, Pottsville, Secretary ; Levi Quier, Reading, Treasurer; Robert Allison, Port Carbon; James Archbald, Jr., Pottsville; William Atkins, Pottsville; D. P. Brown, Lost Creek; William McH. Boyer, Rending; Albert Broden, Reading; George Brooke, Birdsboro; Frank Carter, Pottsville; H. P. Cooper, Pottsville ; J. H. Carpenter, Reading; E. S. Cook, Pottstown; B. Halberstadt, Pottsville; Hakon Hammer, Pottstown; J. Hartshorne, Stowe; M. P. Janney, Pottstown; R. C. Luther, Pottsville; N. Muhlenberg, Reading ; W. H. Morris. Pottstown ; George L. Norris, Reading; G. H. Potts, Pottstown ; H. Potts, Pottstown; S. M. Riley, Ashland ; J. S. Robeson, Pottstown ; Jas. P. Roe, Pottstown; A. W. Sheafer, Pottsville; Heber S. Thompson, Pottsville; Bard Wells, Pottsville; E. C.Wagner, Girardville; N. B. Wittman, Birdsboro. Reception Committee.— George Brooke, Chairman; Robert Allison, J. H. Carpenter, Edgar S. Cook, R. C. Luther, W. H. Morris, H. S. Thompson. Hotel Headquarters.—The Neversink Mountain Hotel, near Reading, Pa. All sessions were held in the hotel. The opening session was held on Tuesday evening, October 11. Mr. Jerome L. Boyer, Chairman of the Local Committee, called the meeting to order, and introduced Mr. John F. Daniel], Jr., VicePresident of the Reading Board of Trade, who delivered an address of welcome, in the course of which the industrial and commercial importance of the city was effectively outlined by skilful use of the statistics of leading branches. From this statement the following particulars are condensed for preservation: The Board of Trade has about 300 members. The annual value of the manofttctures (taking mainly the figures of 1891) is as follows: Iron manufactures, about $16,000,000 (including boilers and flues, $323,000; hardware, locks and butts, $1,650,000; pig-iron, wrought-iron pipe and machinery, $8,400,000; beams, bridge-work and steel, $4,000,000; bolts, nuts, rivets, etc., $1,000,000; stoves, $659,000); silk and cotton goods, $1,725,000; boots and shoes (one concern only), $150,000; ropes and cordage, $600,000; fire-brick, terra-cotta and glass, $320,000; wool and fur hats, $3,000,000; cigars (105 millions), upwards of $3,150,000. The street and elec-

Jan 1, 1893

HENRY TRAPHAGEN, * Toledo, Ohio (written discussion t).-The occurrence of flakes in steel is a perplexing problem, if we consider this condition as a disease rather than a symptom. But if considered as an exaggerated phase of a common disease, flakes will be recognized as old and well-known enemies. I have frequently found flakes in open-hearth steel, converter steel, and even electric steel; and not only in the so-called alloy steels but in dead soft 12-point carbon castings. In fact, I have some twenty flaky test bars that came from a foundry that manufactures converter steel castings. The physical characteristics of such material are striking in their constancy, for the yield point and elastic limit are always high, the elongation is variable, and the reduction of area is nearly always negligible. Soft steels of this kind can easily be bent to an angle of 150° and the only bad symptom is the appearance of incipient cracks on the surface; when the carbon exceeds 30 points, the bending qualities are seriously affected; and when the carbon reaches the neighborhood of 50 points, the bars are generally pulled short. The elongation is peculiar in that it seems to take place along the whole length of the bar, giving a crinkly appearance such as is found in cast brass and monel metal. Of course, this elongation only takes place in the softer varieties of steel. I have stated that flakes in steel represent exaggerated symptoms of a common disease, and that disease is the presence of higher oxides of iron. In every instance that has come to my attention, this condition is coexistent with the presence of oxides in some form. In open-hearth practice when this condition occurs, almost invariably it will be found that the metal has been loaded with ore or that tons of rusty turnings were being melted. In converter practice, one of three conditions is nearly always present: bad cupola practice, the use of oxygenated pig iron, or faulty tuyeres. With the electric furnace, my experience is quite limited, but the few examples of flaky electric steel that have come to my notice were made from a charge of turnings and low-grade light scrap.

Jan 6, 1919

By T. R. Armstrong

During the year 1939, Mexican production totaled 42,479,000 bbl.; a daily average of 116,381 bbl. or a little over 2 per cent of the estimated world production. The Mexican Government operates 100 per cent of the refining branch of the industry, 100 per cent of the domestic distribution, 96 per cent of the crude production and 92 per cent of the total exports. No discussion of the Mexican petroleum industry in 1939 is adequate without reference to the "expropriation" of the foreign-owned oil properties in Mexico by executive fiat on March 18, 1938. The forcible seizing of the properties culminated a long series of efforts on the part of the Mexican Government to obtain control of the oil properties developed through foreign initiative and with foreign capital in Mexico. The heart of the issue is whether the Mexican nation or any nation may with impunity confiscate the legally acquired properties of American citizens. The Department of State of our Government has in its communications to Mexico emphasized the fact that its "expropriation" of American properties was confiscatory because Mexico had failed to make "adequate, effective and prompt compensation"; that the taking was no less confiscatory "because there may be an expressed intent to pay at some time in the future," and that, consequently, "Mexico has assumed and continues to assume to exercise a right without compliance with the condition necessary to give such exercise a recognizable status of legality." Mexico has professed its willingness to pay for the oil properties but at the same time through its Supreme Court it has declared that the owners or lessees do not have the exclusive right to extract and dispose of the oil in the subsoil. This is a reversal of the Mexican position with respect to oil as set forth in the Mexican mining laws, affirmed by Mexican Supreme Court decisions, and as clarified in the Warren-Paync and the Morrow-Calles agreements, as well as in diplomatic correspondence. Efforts to Settle the Controversy Responding to suggestions from the State Department, representatives of the principal oil companies undertook in 1939 to effect a direct

Jan 1, 1940

By C. V. Millikan, C. V. Sidwell

There is nothing more important in petroleum engineering than a definite knowledge of the pressure at the bottom of an oil well at any existing operating condition, and the relation of this pressure to the pressure within the producing formation. A knowledge of bottom-hole pressures is fundamental in determining the most efficient methods of recovery and the most efficient lifting procedure, yet there is less information about these pressures than about any other part of the general problem of producing oil. Determination of Bottom-hole Pressures Bottom-hole pressure may be calculated or determined by several methods. On an inactive well it may be calculated from the fluid head or, if the well is shut in, by adding the casinghead pressure, the static head of the gas and the fluid head. In wells flowing naturally through tubing the pressure at the bottom of the tubing may be calculated by adding the pressure at the casinghead between the tubing and the casing and the pressure due to the weight of the column of gas, but there is always possibility of error caused by fluid being in the annular space above the bottom of the tubing. If a well with tubing is flowing through either the annular space or the tubing, sufficient gas may be injected through the static space to insure that it is free of fluid but not sufficient to establish an appreciable friction loss. The pressure at the bottom of the tubing can then be calculated by adding to the pressure at the tubing head the pressure due to the weight of the column of gas. This is probably the most accurate method of calculating bottom-hole pressures. In wells flowing by gas-lift, the pressure at the point the gas enters the flow may be calculated by a gas-flow formula. Several types of pressure bombs have been used to measure the pressure at the bottom of wells. One is a piece of steel tubing with a check valve in the bottom and a connection for a pressure gage at the top. It is lowered into the well to the point at which the pressure is

Jan 1, 1931