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By A. T. Miesch, L. B. Riley

Distribution of minor elements in sandstone-type uranium deposits of the Colorado Plateau is being studied by the USGS on behalf of the A EC. A primary objective has been to provide basic data which could be useful in geo-chemical exploration for new deposits. The basic statistical measures — similar to those used in sedimentary petrology—are described. The underlying principle is that the frequency distributions fit or approach the log-normal form. Since 1952 the U. S. Geological Survey on behalf of the U. S. Atomic Energy Commission has conducted a study of the distribution of minor elements in sands tone-type uranium deposits of the Colorado Plateau. A primary objective in this study has been to provide basic data which could be useful in geo-chemical exploration for new deposits. Among the basic data considered important are estimates of the abundance and habit of each element in the ore and in the host rocks. It has been found that a few basic statistical techniques, and variations of these techniques, are useful in this type of study. Some of the basic techniques have been used to advantage by researchers in geochemistry and in other fields of geology, especially sedimentary petrology; others have been used to only a limited extent. Among the latter is the linear correlation coefficient, which has proved useful in assessing the element associations in a particular rock type without analysing individual mineral separates. In computing the basic statistical measures a scale has been used which is, in some ways, similar to the phi ($) scale used by sedimentary petrol-ogists in grain-size studies.' FREQUENCY DISTRIBUTIONS It has been recognized for some time that the results of analyses for a given minor element in a suite of samples of rocks or ores yield frequency distribution curves which are approximately normal when the curves are plotted on logarithmic or geometric scales. In other words, the analytical results give an approximate lognormal frequency distribution. A classical example is given by D. G. Krige2 in the study of the distribution of gold values from a mine on the Witwatersrand. Another example is shown in Fig. 1, the distribution of barium concentrations in samples of uranium ore from the Chinle formation. The geochemical data are analogous to grain-size data gathered by the sedimentary petrologist. Both types of data, after simple logarithmic transformations, may be treated by conventional statistical methods based on the normal distribution. This is not to say that other types of transformations may not serve equally well or better for particular element distributions.3 Spectrographers and other analysts are quite aware of the dependence of their precision on the concentration of the element present.4 For example, in the part per million range the variation may

Jan 1, 1961

Coal Division Industrial Minerals Division Minerals Beneficiation Division Mining, Geology and Geophysics Division Established as a Society February 26, 1957 OFFICERS AND COMMITTEES J W Woomer, President A B Cummins, President-elect S D Michaelson, Past President C E Lawall, Eastern Regional Vice-President D W Scott, Central Regional Vice-President 3 D Forrester, Western Regional Vice-President R B Ladoo, Treasurer John Cameron Fox, Secretary

Jan 1, 1959

By Edward Griffith

The anthracite industry, which produces about 50 million net tons of coal annually, has been talked of as being able to last for another century; but if the water record of the past century continues into the expected century, this expectation of many years production still to come out of the remaining reserves will not be attained. The industry will be a submerged one in fact as well as in name. A recorded forecast of what has since occurred appears on page 34 of the Mine Inspectors' reports of 1897: It should also be noticed that bodies of water had accumulated in parts of abandoned mines before duplicate surveys of the same were required by law; and as a result we have today to contend with bodies of water, the exact location and position of which are not correctly known. Since that date, 47 years ago, the implications of the foregoing comment have grown enormously. This is shown in Fig. I and in the following table showing flooded and partially flooded areas that have come into existence since the early 1930's in the northern anthracite field: Number of Year Flooded Areas 1932...................... 2 1933...................... 3 1934..................... 3 1935...................... 5 1936...................... 7 1937...................... 9 1938.................... 11 1939...................... 11 1940...................... 11 1941...................... 14 1942...................... 14 1944...................... 26 Similar conditions exist in other fields in the anthracite region. In the period between 1923 and 1940, abandonment of collieries in the southern field resulted in the flooding of approximately 60 sq. miles (30 per cent) of the field. The ahandonment of collieries in this field has imposed additional expense for pumping on the collieries still operating. This condition will be aggravated by the extension of developments and cause suspension of operations if economic conditions do not justify the assumption of additional pumping costs. During the years, the region's rainfall has not altered, but the quantity going inside the mines through breakages in the surface, brought about by extraction of the coal, has increased materially, as indicated by the ratio of tons of water pumped to tons of coal produced underground for one of the large companies in the northern anthracite field: Year Ratio 1920................. 8.4:1 1925.................. 10.6:I I930.................. II.4:I 1935................. 26.2:1 1940.................. 32.7: I 1942.................. 30.3:I The data in Table I shows the total amount of water pumped and its ratio to underground production for one of the large companies in the southern anthracite field, and shows a rapidly growing serious situation. Rainfall quickly affects the workings in all the fields. In mine inspection district 7 of the southern field the rainfall in 1935 was 92,083,000,000 gal. The total water pumped was 36,274,000,000 gal. (39.4 per cent of the rainfall). The operating mines

Jan 1, 1947

By Edward Griffith

The anthracite industry, which produces about 50 million net tons of coal annually, has been talked of as being able to last for another century; but if the water record of the past century continues into the expected century, this expectation of many years production still to come out of the remaining reserves will not be attained. The industry will be a submerged one in fact as well as in name. A recorded forecast of what has since occurred appears on page 34 of the Mine Inspectors' reports of 1897: It should also be noticed that bodies of water had accumulated in parts of abandoned mines before duplicate surveys of the same were required by law; and as a result we have today to contend with bodies of water, the exact location and position of which are not correctly known. Since that date, 47 years ago, the implications of the foregoing comment have grown enormously. This is shown in Fig. I and in the following table showing flooded and partially flooded areas that have come into existence since the early 1930's in the northern anthracite field: Number of Year Flooded Areas 1932...................... 2 1933...................... 3 1934..................... 3 1935...................... 5 1936...................... 7 1937...................... 9 1938.................... 11 1939...................... 11 1940...................... 11 1941...................... 14 1942...................... 14 1944...................... 26 Similar conditions exist in other fields in the anthracite region. In the period between 1923 and 1940, abandonment of collieries in the southern field resulted in the flooding of approximately 60 sq. miles (30 per cent) of the field. The ahandonment of collieries in this field has imposed additional expense for pumping on the collieries still operating. This condition will be aggravated by the extension of developments and cause suspension of operations if economic conditions do not justify the assumption of additional pumping costs. During the years, the region's rainfall has not altered, but the quantity going inside the mines through breakages in the surface, brought about by extraction of the coal, has increased materially, as indicated by the ratio of tons of water pumped to tons of coal produced underground for one of the large companies in the northern anthracite field: Year Ratio 1920................. 8.4:1 1925.................. 10.6:I I930.................. II.4:I 1935................. 26.2:1 1940.................. 32.7: I 1942.................. 30.3:I The data in Table I shows the total amount of water pumped and its ratio to underground production for one of the large companies in the southern anthracite field, and shows a rapidly growing serious situation. Rainfall quickly affects the workings in all the fields. In mine inspection district 7 of the southern field the rainfall in 1935 was 92,083,000,000 gal. The total water pumped was 36,274,000,000 gal. (39.4 per cent of the rainfall). The operating mines

Jan 1, 1947

By E. B. Snyder, H. M. Kraner

This paper shows that volume stability, low porosity and decreased pyroplasticity are desirable for blast-furnace linings, partitularly for the hearth. It shows further that a hot load test is a valuable means of testing the fusion or softening behavior of a refractory at operating temperatures. The effect of carbon monoxide on commercia1 blast-furnace refractories in their as-received condition and after refiring is reported, showing that many commercial blast-furnace refractories disintegrate badly but that refiring decreases the effect and certain special refractories are now available which are almost free of the tendency. Factors Affecting Choice of ._ Refractories If one were to depend entirely upon experience or trial in the selection of clay refractories, the solution of a problem would be a slow process. Furnace campaigns are so long and attended by so many variables that it is difficult to draw fine distinctions within a reasonable period of time in regard to the quality of refractories used. It could be said, of course, that if service results do not yield the proper information for intelligent choice, there is no difference in the quality of brick being considered, but this is not necessarily true. Conventional ceramic tests are designed to give the ceramic engineer information as to the refractoriness and firing tempera- . ture, which he in turn internrets in terms of volume stability, ability to withstand load at high temperature (pyroplasticity), permeability, chemical stability and re-. sistance to the action of slag. In most refractory applications . several of these factors are involved. In a particular instance, one requirement may be predominant, while in others some other factors may be of primary importance. In this country, clay refractories are generally made from mixtures of plastic and flint fire clays. The process of firing a clay refractory is one of slowly melting the constituents, and during this operation its porosity is gradually reduced. The process is arrested, of course, in its incipient Stages and the Progress is determined by measuring slight changes in porosity, volume, bulk gravity, etc., that have taken place. Often the temperatures to which clay refractories are exposed in service are higher than those employed in their firing. However, if the manufacturer were to fire them at such high temperatures the brick would distort. Therefore it would be difficult for the manufacturer to fire all of his clay refractories to temperatures at which they are to be used, although in many cases it would be desirable from the user's point of view if he would do so. The porosity of clay refractories decreases by firing, to a minimum limit, after which a further increase in the temperature causes expansion in certain clay constituents and bloating in others. Both may occur in the same refractory containing two such clays.

Jan 1, 1944

By H. M. Kraner, E. B. Snyder

This paper shows that volume stability, low porosity and decreased pyroplasticity are desirable for blast-furnace linings, partitularly for the hearth. It shows further that a hot load test is a valuable means of testing the fusion or softening behavior of a refractory at operating temperatures. The effect of carbon monoxide on commercia1 blast-furnace refractories in their as-received condition and after refiring is reported, showing that many commercial blast-furnace refractories disintegrate badly but that refiring decreases the effect and certain special refractories are now available which are almost free of the tendency. Factors Affecting Choice of ._ Refractories If one were to depend entirely upon experience or trial in the selection of clay refractories, the solution of a problem would be a slow process. Furnace campaigns are so long and attended by so many variables that it is difficult to draw fine distinctions within a reasonable period of time in regard to the quality of refractories used. It could be said, of course, that if service results do not yield the proper information for intelligent choice, there is no difference in the quality of brick being considered, but this is not necessarily true. Conventional ceramic tests are designed to give the ceramic engineer information as to the refractoriness and firing tempera- . ture, which he in turn internrets in terms of volume stability, ability to withstand load at high temperature (pyroplasticity), permeability, chemical stability and re-. sistance to the action of slag. In most refractory applications . several of these factors are involved. In a particular instance, one requirement may be predominant, while in others some other factors may be of primary importance. In this country, clay refractories are generally made from mixtures of plastic and flint fire clays. The process of firing a clay refractory is one of slowly melting the constituents, and during this operation its porosity is gradually reduced. The process is arrested, of course, in its incipient Stages and the Progress is determined by measuring slight changes in porosity, volume, bulk gravity, etc., that have taken place. Often the temperatures to which clay refractories are exposed in service are higher than those employed in their firing. However, if the manufacturer were to fire them at such high temperatures the brick would distort. Therefore it would be difficult for the manufacturer to fire all of his clay refractories to temperatures at which they are to be used, although in many cases it would be desirable from the user's point of view if he would do so. The porosity of clay refractories decreases by firing, to a minimum limit, after which a further increase in the temperature causes expansion in certain clay constituents and bloating in others. Both may occur in the same refractory containing two such clays.

Jan 1, 1944

INDEX TO TRANSACTIONS After a delay of many months, which is very much regretted, but which, it is hoped, will be one means of insuring a volume of accuracy where accuracy is very important, the Institute now has for distribution copies of the index of Volumes XXXVI to LV, inclusive. This is more than a mere index off names of authors and titles of papers. Every important topic under consideration by author or discusser is introduced under such key-word as will enable an engineer to locate the desired information with the minimum expenditure of time. This index sells for $5* in half morocco binding and $4*. in paper covers. With the index of Volumes II to XXXV (which sells for $5 in half morocco and $4 in paper covers), it forms a complete index of the first fifty-five volumes of the Institute's Transactions. These collective indexes are very valuable to members of the Institute, enabling them to look up matters in their own library; if they have the volumes to which the indexes refer, they can get the information at once, and, if not, they can readily determine whether or not a visit to a nearby public library is desirable.

Jan 7, 1918

By B. A. Wilcox, A. H. Clauer

DURING the course of an investigation on the high-temperature creep behavior of TD Nickel* (Ni + 2) vol pct ThO2), it was observed that the creep fractures were similar in appearance to low-temperature ductile fibrous fractures and creep ruptures by cavitation. Microfractographs of fibrous ruptures are typically characterized by a dimpled appearance, with second-phase particles frequently found near the bottom of the dimples.'-4 These somewhat resemble creep ruptures by cavitation, in that fracture occurs by void formation, with the subsequent growth and final merging of the voids to form a complete fracture.' It is the purpose of this communication to describe the creep fracture of TD nickel and suggest a mechanism for the rupturing process. The discussion is relevant to material crept to fracture in vacuo at a constant stress of 18,000 psi, over the temperature range 900" to ll00°C. The material used in this investigation was 1/2-in.-diam bar stock supplied by Du Pont, contain- ing 2.3 vol pct Tho2. The final fabrication treatment consisted of -95 pct reduction by swaging followed by a 1-hr anneal at 1000°C. Transmission and replica electron microscopy revealed that the material had a fibered structure with a transverse grain size of -1 µ and a longitudinal grain size of 10 to 15 µ. Selected-area diffraction indicated that the fiber axis was parallel to (00l), in agreement with the results of Inman et a1.6 The thoria particle size varied from 80 to 1000Å, with an average size of 400Å, and the mean particle spacing was about 1200Å. The remarkable structural stability7 was confirmed by annealing for 6 hr at 1300°C (about ' 0.9 the absolute melting point). Transmission electron microscopy revealed that the only structural change was a slight decrease in dislocation density. Furthermore, recrystallization or grain growth during creep has not been observed. All specimens were annealed in vacuo at 1300°C for 3 hr prior to creep testing. The following times to rupture were obtained for vacuum creep tests at a constant stress of 18,000 psi: 900°C, 854 hr; 930°C,

Jan 1, 1965

By Raymond M. Howe

Additional data have been secured on the disintegration of furnace linings and the spalling of stove brick. The first article on the disintegration of furnace linings appears to have been written by John Pattinson in 1876.l The furnace involved was 85 ft. (25.0 m.) higher and 27 ft. (8.2 m.) in diameter at the boshes; after being in blast five years, the top brick became contaminated with carbon and disintegrated. An examination of the lining showed that the discolored, disintegrated brick were in a zone found from 35 to 67 ft. (10.6 to 20.4 m.) above the hearth; immediately below, in a zone extending from 22 to 40 ft. (6.7 to 12.1 m.) above the hearth, the brick were hard and porcelain-like in appearance. Analyses of samples taken from the different sections are given in Table I. The water-soluble portion found in the sample taken 39 ft. (11.8 m.) above the hearth had a composition approximately as follows: silica, 0.50 per cent.; lime, 0.04 per cent.; potash, 0.78 per cent.; soda, 0.20 per cent.; potassium chloride, 6.19 per cent.; moisture, 1.03 per cent.; total, 8.74 per cent. The carbon Table 1.—-Analyses of Samples Taken from Diferent Sections of Furnace . I ii In Iv v Section 67 Section 45 Seotion 39 Section of Original ft Above ft above ft above vitrified Lining Hearth Hearth Hearth Portion Per Cent. per Cent per Cent per cent. per Cent Silica........................... 55.70 55.60 55.67 47.60 37.07, Alumina........................ 35.50 35.40 30.00 26.47 23.18 Ferric oxide..................... 3.00 1.32 0.96 Lime........................... 0.23 0.06 0.17 Magnesia....................... 1.22 0.95 0.86 0.00 Potash......................... 2.60 2.10 5.30 7.54 21.59 Soda.........,.................. 0.45 0.42 1.67 0-76 6.28 Ca1bon ......................... 2.05 3.24 5.97 Carbon dioxide.................................. 2.. 17 Water...................................... 7.70 Water-soluble........................... 8.74

Jan 1, 1920

By Martin Rubenstein

CdS crystals have been grown from a number of metallic solvents such as bismuth, tin, lead, and cadmium. Etching studies have shown that plastic deformation occurs if the crystals are not removed from the solvent prior to the solidification of the solvent, on cooling. The deformed crystals show a umique exciton fluorescence as a function of edge dislocation density. If one grows the CdS in the eutectic alloy of the above four metals (commonly called Wood's metal) the crystals can be removed from the solvent with hot water and no plastic deformation occurs. In this paper, the liquidus solubility measurements of CdS, as a function of temperature, are presented. The data were obtained using a high -temperature filtration technique. CADMIUM-SULFIDE crystals have been grown from a number of metallic solvents1 such as cadmium, bismuth, tin, and lead. Liquidus solubilities of CdS in cadmium,2 bismuth,3 and tin4 have already been measured. Crystals of CdS, in all four metals, have been grown by solution growth: 1) by cooling a saturated solution and 2) by a solution transport method.1'"1 CdS crystals grown in these four solvents have a few characteristics in common: 1) 1.8°K photolumines-cent emission consisted mainly of the radiative recombination of the bound exciton commonly known as I,, 2) slip lines which could easily be seen by the naked eye, and 3) edge dislocation densities in the order of l05 per cu cm.1 It was decided that these slip lines and the high edge dislocation densities were caused by a plastic deformation of the CdS crystals. It was felt that this plastic deformation did not occur during the growth of the crystals nor during the cooling of the solution, but did occur when the solvent which was in contact with the crystals froze. If these assumptions were valid, the slip lines and the high number of dislocations could be reduced or eliminated by removing the crystals from the solvent before the solvent froze. Since crystals of CdS had already been grown separately in such solvents as bismuth, lead, tin, and cadmium, it was felt that crystals could be grown in a eutectic mixture of these four metals. In this work a eutectic (or near eutectic) mixture of bismuth, lead, tin and cadmium in the proportion 50, 26.5, 13.5, and 10 wt pct, respectively, was used to grow CdS crystals. Such a mixture has a melting point of about 70°C and is close in composition to the alloy commonly known as Wood's metals. If the crystals could be grown from this mixture of solvents, and if hot water (>75°C) could be used to separate the crystals of CdS from the metallic solvent, it was hoped that CdS crystals could be grown with little or no plastic deformation which had been ob- served when crystals were grown from these solvents uncombined. CdS crystals were grown from this low melting eutectic mixture of bismuth, lead, tin, and cadmium using the solvent transport method. CdS powder and the appropriate amount of metals were sealed in a quartz tube under a pressure of about 5 X 10-6 torr. This ampule was then placed in a vertical position in a furnace. The temperature was raised to about 900°C. The furnace was designed so that the top of the liquid column within the ampule was between 10° to 40°C higher than the bottom of the liquid column. These temperatures were measured on the outside of the quartz ampule. The ampule was maintained at temperature for 7 to 14 days (depending on the temperature at which transport was taking place) and then the furnace temperature was lowered until the temperature was about 125°C. The ampule was then removed from the furnace, placed in water maintained at about 90°C, and opened in this 90°C environment. The crystals could then be removed from this two-phase liquid (Wood's metal and water) by mechanically picking them out. Alternatively, the crystals could be quantitatively removed by adding an excess of mercury to the mixture of metals, crystals, and hot water. The hot solution of metals and the hot water could be evacuated using a small diameter tube connected to a vacuum. Small amounts of mercury and water could be removed by heating the crystals in vacuum. Crystals prepared using this technique showed no evidence of slip. However, some of these crystals did show edge dislocation densities as high as l04 per cu cm. Some few selected crystals showed no dislocations. Single crystals of CdS were grown as large as 5 by 5 by 0.5 mm. The ampules for the growth of these crystals were 13 mm O.D., 11 mm I.D., 150 mm! LIQUIDUS SOLUBILITY MEASUREMENTS The CdS starting materials was G.E. 118-8-2 powder which was fired in H2S at 1000°C, and then a vapor transport technique5 was applied to produce a "sound" mass of CdS. The Wood's metal was prepared by weighing out bismuth, lead, tin, and cadmium in the proportions of 50, 26.5, 13.5, and 10 wt pct, respectively. The bismuth, cadmium, and lead were from the American Smelting and Refining Co. (ASARCO) and all had purities of 99.999+ pct. The tin was 99.9999 pct spectroscopic grade from the Vulcan Materials Co. The appropriate mixture was placed in a quartz tube, evacuated to a pressure of 5 X 10-6 torr, melted to a liquid, cooled to room temperature under this same vacuum. This ingot was then placed in another quartz tube, evacuated to 5 x l0-6 torr, and sealed off under vacuum. The ampule was then horizontally placed in a furnace. The temperature was raised to 600°C, and over a period of several hours the ampule was vigorously shaken several times. The ampule was then removed from the furnace, and the metallic liquid was

Jan 1, 1970

By AIME AIME

WHEN Russell B. Paul was born in Russell Gulch, Gilpin County, Colorado, that district was the state's leading gold producer. The son of Dr. Henry Paul, who had gone to Colorado from Missouri during the golden era following the Civil War, and had joined the Institute in 1889 when he was manager of the famous Aspen mine, young Paul's early life was steeped in a mining atmosphere from which developed his selection of mining engineering as a profes¬sion. After receiving his E.M. degree from the Colorado School of Mines in 1902, Mr. Paul worked in Colorado and Honduras. Returning from Central America he was married to Mary Ellen Gilmour, daughter of a prominent Central City mining man;

Jan 1, 1943

By Wilber Stout

In Ohio, the annual output of coke made from native coals has averaged not more than 70,000 tons, or about enough to run a 200-ton blast furnace. Raw coal locally mined from the Sharon, or No. 1, bed was used for iron smelting in Mahoning furnace at Lowellville, Mahoning Co., as early as 1846. This practice was continued in the Youngstown district until the coal became scarce and the Connellsville coke more popular. At present, the Sharon bed contributes a part of the fuel for the production of ferrosilicon iron at Jackson, Jackson CO. About one-third native coal and two-thirds soft coal are used. In this state, coke, on a commercial basis, was first made in Jefferson County probably about 1861 or 1862. The coals used were the Steuben-ville Shaft, or Lower Freeport, and the Strip Vein or Middle Kittanning. The practice, however, was discontinued before 1880 because of the competition of superior foreign cokes. Beehive ovens, later built at Leetonia, Columbiana Co., were operated for only a few years; the coal used at this place is the Lower Kittanning or No. 5. In a desultory way, slack from the Pittsburgh coal has been coked at a few places in eastern Ohio, and attempts, either for experimental or for commercial purposes, have been made in other parts of the state. Small quantities of coke were made from the Upper Freeport coal at Salineville, Columbiana Co., and near Nelsonville, Hocking Co.; the results were poor. Tests were made of the Middle Kittanning coal near Zanesville, Muskingum Co., at Moxahala Furnace, Perry Co., and at Washington Furnace, Lawrence Co.; the cokes were all high in sulfur and ash. Attempts were made to coke the Clarion coal at Vinton Furnace, Vinton Co.; a small battery of molding ovens and a pile of high-sulfur coke yet remain to tell the story. The Pittsburgh coal was coked on a commercial scale at Utley and at Lathrop, Athens Co., but the operations were not successful and were soon abandoned. These failures and indifferent successes are not to be attributed to a lack of demand for a first-class coke, as Ohio has held a commanding place for many years in iron smelting; nor to a deficiency of coals, as the state has a vast reserve of such material. They are to be ascribed to the inferior quality of the native products offered to the trade. The cokes

Jan 1, 1920

By J. B. Clark

In 1933, R. paris1 published a phase diagram for the entire Mg-Ca-Zn system. He reported the existence of a ternary intermetallic phase, Mg5Zn5Ca2, which formed a quasi-binary with the magnesium solid solution. Since then, no extensive work has been reported on the system. Recently however, indications of the existence of a second ternary in-termetallic phase in equilibrium with the magnesium solid solution led to a reinvestigation of the solid phase equilibria involving the magnesium solid solution. The 335°C (635°F) isothermal section was chosen for study. Metallography and powder X-ray diffraction were selected as the best mutually corroborating methods for determining the solid phase constitution. Seventy-six alloys were prepared from singly sublimed (99.95 pct) magnesium, electrolytic (99.95 pct) zinc and USP calcium. The analyses of some of the alloys are shown in Fig. 1. The alloys were melted in a graphite crucible under a chloride flu and chill cast in a split graphite mold. Dif-fusion couples (see Fig. 2) were prepared by casting molten Mg-20 wt pct Zn alloy around a cylinder of Mg-30 wt pct Ca alloy. The alloy samples and the diffusion couples were sealed under argon in Pyrex vials and annealed in a furnace capable of controlling within 1/2°C of 335°C. At the conclusion of the anneal, the alloy samples were quenched in ice water and the diffusion couples were air cooled. Procedures standard for magnesium alloys were used for metallographic examination. Powder X-ray diffraction patterns were taken on a G. E. camera with a 14.32 cm dim using nickel-filtered copper radiation. The redetermined 335°C (635°) section of the Mg-Ca-Zn phase diagram is shown in Fig. 1. TWO ternary intermetallic phases, designated w and

Jan 1, 1962

By H. H. Rachford, and J. D. Rice

The effectiveness of digital computing machines in making technical calculations depends on how well the work is arranged to utilize the capability of the machines. This note presents a particularly useful way of calculating hydrocarbon vapor-li.quid equilibrium in the flash vaporization (or condensation) system. The method is well suited to sequence-controlled computing equipment. It is not limited to equilibrium calculations and may be used for solution of most implicit equations in one variable. INTRODUCTION There is increasing interest in the use of electronic digital computers in research and engineering calculations. This is a fortunate and inevitable trend in view of both the increasingly extensive numerical work which is becoming a routine part of many daily production operations and growing demand for the overwhelming amounts of calculations required by newly developed numerical methods for solving heretofore unsolved problems. Machines are in many ways ideally suited to the task but of necessity present certain difficulties. for a particular poblem to be solved must often be formulated quite differently from the way it would be arranged for manual solution. This is done in order to take advantage of the inherent speed and precision of electronic computers and at the same time to limit the need for number storage to the capacity of the machine. Therefore, this note is submitted to present a general and quite powerful method of finding solutions of the frequently encountered implicit equation: F(x,y1,y2,...ya)=0.......(1) where the root, x, is to be found for a given set of y1, ... yn.. The procedure is well suited for use with computing machines, for it usually requires but little storage or programming beyond that necessary to evaluate F. HYDROCARBON EQUILIBRIUM The method is described in terms of the problem it was designed to solve, i.e., the calculation of hydrocarbon vapor-liquid equilibrium in flash vaporization. Given the composition of a hydrocarbon mixture and appropriate values of the equilibrium ratios K, to find the phase ratio and compositions in a closed system: let z, be the mol fraction of the i-th component in the mixture. If K, is the ratio yl/xl, where y, and x,

Jan 1, 1952

By G. A. Beske, P. Hilsch, J. Wulff

The effects of the growth precipitates on the su-perconduching properties of an Al- 15 al. pel Zu alloy have been studied using magneization, transition lem-perature, and residual resistivity measurements. Aging at 230C for 1/2 to 11 he produces an increase in Hfp, Ike field of first penetration, and tut increase in trapped flux. The upper critical field, Hc2 remains constant for such aging tunes. Aging at 200°C produces a decrease in Hfp and an increase in trapped flux. The transition temperature remains constant at Tc - 1.227° ± 0.02°K for aging at 220°C for tims of from 1/2 to 10 hr, and for aging at 200°C it remains constant at Tc. = 1.18° i 0.02°K for times from 1/2 hv to 26 hr. The observed behavior indicates that the superconducting matrix when aged at 220°C behaves tike a type U su-perconducior, but when aged at 200°C behares like a type I superconductor. The magnetization changes after aging can be attributed to the growth and clutnge in distribution of the precipitate in a matrix of fixed composition. IT has been realized for some time that the superconducting properties of alloys are highly structure-sensitive. This is evident in the work of Mould and Mapother1 who examined the properties of an aluminum alloy. Precipitation effects have also been briefly mentioned in other studies.2-4 Bonnin and coworkers5 have observed a sharp inc rease in trapped flux in an A1-Mg alloy when the residual resistivity reaches a value that indicates it is a type II superconductor. Recently Blanc, Goodman, and Nemoz5p have reported on precipitation effects in A1-Ag alloys. Detailed studies of precipitation in Pb-Sn and Pb-Cd alloys made by Livingston6 serve to show that the upper critical fields are enhanced by quenched-in solute. Furthermore. at various stages in the precipitation process? the upper critical field is determined largely by the remanent solute. The observed magnetic hysteresis and trapped flux in such alloys result from the interaction between precipitate and the flux filaments in the mixed state. The flux trapping appears to depend largely on the precipitate distribution and is greater if the superconductor is type II than if it is type I. To examine the effect of precipitation in another alloy system, particularly one in which the composition of the superconducting phase does not change significantly during the course of precipitation, the Al-Zn system seems interesting, especially in view of the transition temperature and resistivity studies of Chiou and seraphim.' Furthermore, the recent detailed electron-microscope studies of an Al-Zn alloy by Richards and Garwood8 provide a guide for relating superconducting properties to changes in structure. For these reasons, magnetization, transition temperature, and residual resistivity measurements for varying times of heat treatment at two temperatures were made with a -15 at. pct Al-Zn alloy. The results are reported in this paper. I) EXPERIMENTAL The alloy used was prepared by Cominco Products Inc. from 99.9999 A1 and 99.999 Zn. It was chill-cast, swaged, and drawn to 0.125-in.-diam rod. The analyzed composition was 15.6 at. pct Zn (31.1 wt pct). A jeweler's saw was used to cut the 0.125-in.-diam rod into the 0.875-in. lengths needed for magnetization measurements. The ends of the cylinders were slightly beveled to remove the sharp edges. A portion of the original 0.125-in.-diam rod was drawn into 0.010-in.-diam wire and used for transition temperature measurements. Specimens were suspended from wires within a vertical furnace during heat treatment. All were homogenized at 500°C for a minimum of 3 days and subsequently solutionized for times in excess of 6 hr. The solutionizing temperature was held constant to +3°C. Individual specimens were homogenized, quenched, and aged several times and no effects indicating loss of zinc were noted. The suspended specimens were quenched by cutting the wires and allowing the specimens to fall into a silicone oil bath held at the aging temperature. They were then isothermally transforked by aging in the same bath used for quenching. After aging for the required time (approximately 10 min aging was necessary before the upper critical field reached a fixed value), they were briefly (1 to 2 sec) dipped into an acetone bath at room temperature to remove adherent oil and then immediately transferred to liquid nitrogen where they remained until inserted into the helium bath (usually within an hour). The temperature of the aging bath was held constant to +3°C for longer aging times. The cryostat used for the measurement of superconducting properties consisted of outer and inner dewars for liquid nitrogen and liquid helium, Stokes 6-in. booster diffusion pump and Stokes Model 212 mechanical pump, temperature controller to measure and control the temperature of the helium bath, and a superconducting solenoid with inserted search coils to provide the magnetic field and measure the magnetic moment of the specimens. A schematic diagram of the cryostat is shown in Fig. 1. An ultimate temperature of 0.85°K was reached with this apparatus. The temperature controller used is similar to the one described by Blake and chase.' A 0.5 pct Allen-Bradley carbon resistor and a nichronle heater (200

Jan 1, 1968

By R. H. Widmyer, G. M. Wood

This investigation was prompted by the absence of a simple, accurate method to predict optimum second stage separation pressure in three stage separation operations. Three stage separation as used here includes two separators plus the stock tank. The first stage pressure is usually fixed by gas sales conditions and the third stage is at atmospheric pressure. Thus, the second stage pressure is the only one that may be varied in-discriminantly during production operations. No variations in temperature were considered in this study, even though it will vary among systems, for a change in temperature has little effect on the optimum pressure. Optimum pressures may be determined from flash calculations, but these are tedious unless a computer is available. An early attempt to develop a simpler method&apos; yielded an equation which gave the optimum pressure only as a function of initial and final pressure. Experience, however, confirms theoretical relationships which show that composition as well as pressure and temperature must be a factor. This indicates that the basic relationship should be an equation of the form, where P, is second stage pressure, P, is first stage pressure, A is a function of P. (stock-tank pressure) and the system composition, and n is a function of the number of stages and the system composition. Fig. 1 shows the basic variation of P2 with P for a fixed system composition. A series of such figures clearly showed the effect of composition. The peak of each curve reflects that second stage pressure at which the stock-tank recovery (gal/MMcf) residue gas is a maximum value. DEVELOPMENT OF NEW CORRELATION Wellstreams having 17 different analyses, ranging from low gravity crude to condensate, were used to determine the effect of composition. Each wellstream was flashed through three stages to determine the optimum second stage pressure for each first stage pressure. Equilibrium vaporization ratios proposed by Latham and Campbell were used throughout. The heptane plus fraction, for simplicity, was assumed to have the properties of octane. The results were subjected to an empirical analysis in an attempt to develop a correlation- that would be (1) simple, (2) accurate, and (3) eliminate the need for any flash vaporization calculations. This analysis yielded two equations, one for wellstreams having a specific gravity greater than one (air = 1.0) and one for those less than one. For crude streams (specific gravFor condensate (specific gravity < 1.0),

By H. E. Hawkes, D. A. Barr

Time variations in the copper content of the sediments of streams draining mineralized areas were studied in two areas of contrasting climatic environment, one in northern and one in southern British Columbia. In each area, samples were collected and observations made of rainfall, stream discharge and air and water temperature at intervals throughout the summer season. Samples were analyzed for total and cold-extractable copper. Results showed a weak inverse relation between cold-extractable copper and discharge in two out of the three test sites in the southern area, and a decrease in ratio of COld-extractable to total copper over the duration of the test period at a highly anomalous site in the northern area. In suspended rock flour resulting from glacial erosion of mineralized rock in the northern area, virtually all the copper was found to be soluble in cold, dilute hydrochloric acid. None of the variations observed is sufficient to cause serious problems in geochemical sediment surveys. Systematic collection and trace analysis of stream sediments has seen wide application in recent years as a method of primary prospecting in primitive areas. Common practice is to collect fine-grained samples of sediment either from the active channel or from the flood plain near the channel. Samples are dried, sieved and the -80-mesh fraction analyzed after breakdown of the sample by a relatively strong attack, such as by fusion or by treatment with hot perchloric acid. Drying, sieving and rigorous chemical attack requires established facilities, either in a well equipped central laboratory or in base camp. Thus analysis for total metal involves a substantial delay from the time the samples are collected until the analytical data can be reported. An alternative system uses a cold aqueous extrac-tant in place of the hot acid or flux.4 Advantages of the cold-extraction techniques are that kits can be prepared for use directly at the sample site and that, in some problems, the patterns in cold-extractable metal, usually abbreviated cxMe, are more useful as ore guides than the patterns in total metal.&apos; In the course of operational geochemical sediment surveys, a problem that has come up repeatedly is failure to reproduce anomalous values or patterns by resampling the same areas. The mystery of the vanishing anomaly has led to speculation as to whether there is a significant variation in the metal content of sediment samples with the weather or with the time of year. Review of the published literature shows that a number of experiments have been carried out on time variations in the metal content of stream water.1,2,5,7-9 The only published report on time variations in stream sediments that has come to the authors&apos; attention, however, is by Govett,3 working in Northern Rhodesia.

Jan 1, 1963

By Mark C. Malamphy

MAJOR JUAREZ TAVORA, who recently accepted the post of Minister of Agriculture in Brazil, has reorganized his department. Not least among those sub: divisions of the "Ministerio" which underwent radical changes in the general reform was the Serviqo Geologico e Mineralogico do Brasil. This well- known organization was declared extinct, and in its place was created a new cleparttnent &apos; termed "Departamento Nacional cle Producqao Mineral," which immediately took over all the work of the olcl Servico Geologico ill addition to certain new duties. Dr. .. Domingos Fleury- da Rocha, former head of the School of Mines of Ouro Preto, was called to Xio to assume the newly created post of Director General of the department of Mineral Production. His department will have live divisions :

Jan 1, 1934

By Kenelm C. Appleyard

In introducing to an American audience a description of the work done in dry coal separation in England and in Europe generally, it is perhaps desirable to give a short history of the development outside the United States of the particular processes with which the author is connected, and perhaps to stress a little the differences in the nature of the conditions to be faced. England actually presents one set of problems and the Continent of Europe another, since the character of the coals to be treated is entirely dissimilar, and the attitude of the coal industries towards coal preparation is also dissimilar. England for generations has been working by hand good seams of clean coal of the highest possible quality and has not felt any pressing need to clean its coal. Most Continental countries, however, especially in Central and Western Europe, have been working friable and often very dirty coals for so long that a washery is accepted as a part of the normal equipment of a colliery, with the result that the art of wet washing has reached a high state of perfection, particularly in Belgium and Germany. The advent of machine mining has intensified the problems to be faced in all countries, and in England has been coupled with the working out of the best seams in the older coal fields, thus bringing about the necessity of working thinner and dirtier seams with resultant difficulties as regards marketing the products, while Poland, with clean and well prepared coal, has in recent years been attacking established British markets in Scandinavia. In recent years, therefore, interest in coal preparation has been steadily gaining ground in England, although it has not yet reached Continental dimensions. Broadly speaking, the differences in preparation problems between England and the Continent boil themselves down to one of size. In England, for example, with the exception of the Kent coal field, the proportion of coal of a size less than ? in. to the coal less than 2 in. is very much less than on the Continent, and since the principal difficulties in dry cleaning lie in the fines it is easier to produce good figures on

Jan 1, 1931

By John L. Boardman

The Anaconda company has never indulged in any employee activities at Butte which might be termed paternalistic, but it has exerted a vast amount of effort in care of its employees during working hours. The reason for this policy is not lack of interest or that the company does not feel the effect of employees&apos; activities while they are "off the job"; it is that the company and the city of Butte have grown up together and each has been adequate in its own sphere, the company in providing employment at the highest possible wage and the city in providing housing, sanitation, commercial services, medical services, schools, churches, amusements and entertainments. The one exception to this independence between the company and the community is the Butte Water Co., which is a wholly owned subsidiary of the Anaconda Copper Mining Co. Mention of this relationship is made here because the water supply of such a city as Butte is one of the principal factors in determining the health of the people. Very early in the development of the Anaconda company an adequate and dependable water supply for the operations became necessary, therefore the company took over this important community function. So well has this activity worked out that during the whole period of time covered, in which the company has expanded to become practically the sole mine operator and the community has grown from a small mining camp to the status of a modern city, there has been no shortage of water or any outbreak of water-borne, epidemic disease. Conditions Leading to Organized Safety Effort A brief sketch of conditions in Butte prior to 1912 is necessary to an understanding of the reasons for placing accident prevention on an organized basis. As early as the year 1884 there were a large number of small independent mining operations depending principally upon the production of silver, although even then copper was becoming prominent in the value of total production for the district. The Butte camp was then just emerging from the log cabin stage to that of a modern city.

Jan 1, 1940