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WELL known member of the Institute, Henry Krumb, survived the Japanese earthquake and has written a most interesting description of his personal experience to a friend in New York, an extended excerpt from which we publish, by permission, below. Not having been written for publication it has increased value as a human document in its vivid description of personal impressions and sensations in the midst of such a catastrophe. The earthquake was the most terrible experience I have ever passed through. We arrived at Miyanoshita, Friday, Aug. 31, about 6 p.m., having left Yokohama about 2:30 that afternoon by automobile. It was a most beautiful ride, although rather warm, but not unusually so, as it has been uncomfortably hot ever since we arrived in Japan. The first part of this automobile trip was along the old highway from Kyoto to Tokyo, which is lined with fine old pine trees. There are 52 villages along this highway and we saw real Japanese country life: naked children, both boys and girls, and men wearing nothing but gee-strings. The country on either side was intensively cultivated, the green rice fields and lotus ponds making a most beautiful sight. The occasional hills were all re-forested with young pines. In places the road runs close to the ocean beaches. The last part of the trip was up a steep mountain road, cut out of the side of the mountain. On one side of the road, in the gulch below, was a roaring river. The road crosses this river several times. Miyanoshita is beautifully located on the side of a mountain about 400 ft. above this river at an altitude of 1400 ft. The grounds of the hotel are laid out in Japanese style, small lakes with fish, waterfalls and dwarf trees making a very pretty sight. On the morning of Sept. 1, after walking around the garden and the hotel, we went to our room and I started to write up a few notes. Mrs. Krumb was reading a guide book. A few minutes before noon she came over to the table where I was writing and said that it was about lunch time. Just at that moment hell broke loose. It was the first earthquake I have ever experienced and I did not immediately realize what was happening. The building was shaking as a mine office might shake when heavy blasting was going on near by. Mrs. Krumb, having experienced many earthquakes, stepped to the open door between our room and the bathroom and called to me to get out from under the chande-lier. The plaster was commencing to fall and a large wardrobe fell over. I then knew what was happening and ran to the win dow. Before I reached it a large chunk of plaster from the ceiling hit me on the head and cut my forehead and nose. Mrs. Krumb ran for the other window just as the marble mantelpiece and the dresser fell. Without any hesitation, she jumped out of the win-dow and I followed suit out of the other. Luckily neither of us sprained an ankle-we had jumped 8 ft. We started to runaway from the building but had not gone more than 25 ft. when a second shock or rather a continuation of the first became so violent and the ground under our feet was trembling so that it was almost impossible to stand up without holding on to a tree. The ground seemed to have become liquid and rocked violently, it seemed to me in a vertical direction. In some later shocks the movement was more horizontal. About this time Mrs. Krumb saw the blood on my face and commenced to break down, but only for a moment: As soon as she saw it was not serious she was all right and during the following days stood the experiences and hardships as well as the best of them:

Jan 11, 1923

By E. C. Hopkinson, A. H. Youmans, R. A. Bergan, H. I. Oshry

A new log has been developed for quantitative formation evaluation which is based on a measurement of the length of time slow neutrons survive before they are captured in the rocks and fluids. The logging instrument employs a cyclically pulsed neutron generator and a gated scintillation counter which is synchronized with the source. The source emits short, intense bursts of 14 mev neutrons once every 1,000 microsec and is quiescent between bursts. During the period the source is quiescent, the detector is electronically actuated for two independent preselected intervals. A comparison of the counting rates during these two intervals gives a measure of the rate of decay of the slow neutrons and of the associated gamma radiation. The average neutron lifetime in most earth formations is in the range from 50 to 500 microsec. It can be measured during a continuous logging operation at conventional logging speeds. The design of the logging instrument is described and the results of tests are compared with theoretical predictiom. Formulas are developed which give the relationship between log response and formation properties. It is shown that the method is particularly sensitive to formation fluid salinity, and that salt water saturation can be measured accurately in either cased or open hole. The measurement can be made independent of borehole size, fluid type, casing and tool position in the hole by properly selecting the intervals during which the measurements are made. The results of tests with a prototype logging tool are given. INTRODUCTION A new nuclear logging system has been developed which employs the Accelatron,* an accelerator-type neutron source, and accurately measures formation brine saturation in an entirely new way. It has produced a type of formation log with better sensitivity, greater sampling depth and simpler quantitative interpretation than any other nuclear log thus far suggested. The new Neutron Lifetime Log* employs a pulsed electromechanical neutron source and a synchronously gated radiation detector. A prototype instrument has been field tested during recent months to demonstrate the operability of the apparatus and the feasibility of the method. Tests in wells and simulated boreholes have confirmed theoretical predictions and have shown that formation param ters can be measured independent of casing and other borehole parameters. Preliminary results of field tests have indicated that the log may have important and widespread applications. BASIC PRINCIPLE OF NEUTRON LIFETIME LOG The Neutron Lifetime Log is based on the fact that neutrons emitted by a source in a well are rapidly but not instantly captured by the material around the source. Their capture is a matter of statistical probability; the greater the number of capturing nuclei and the greater the "capture cross section", the greater is the probability that a neutron will be captured quickly. The average life of a thermal neutron in vacuum is about 13 minutes, but in common earth materials, the average neutron life ranges between extremes of about 5 rnicrosec for rock salt and perhaps 900 microsec for quartzite. The Neutron Lifetime Log responds to variations in this average neutron life. The theoretical basis for a log of this general type has been well understood by nuclear logging experts in many laboratories both in America and in Russia, and develop mental work along these lines has been in progress for many years. The Russian literature has reported both theoretical and experimental work1,2 but in this country there have been no published reports of progress toward a practical logging instrument. The logging instrument is designed to measure radiation produced by slow neutrons during selected intervals when no neutrons are being emitted by the source. The source is arranged to emit neutrons in bursts or pulses. During the quiescent interval between the pulses, it is possible to observe the exponential "decay" of the neutrons and the neutron-induced radiation as the individual neutrons progressively disappear due to capture by atoms in the formation or the borehole. When a short pulse of 14 mev neutrons is emitted by a source in a borehole, the individual neutrons are slowed to thermal energy within a few microsec. Thus, a cloud of "slow" neutrons is formed around the source within 10 to 50 microsec after the pulse. This cloud is most dense within a few inches of the source, and is progressively less dense out to a radius of about 3 ft, where radiation from the source is practically undetectable.

Jan 1, 1965

By E. D. Levine

A study was made to delineate the dislocation mechanistns controlling prismatic and basal slip at low temperatu.ves in titanium containing approximately 100 ppm interstitial impurities. Mechanical tests were performed on single crystals prepared from electron-beam zone-refined crystal bar by a thermal cycling technique. Measurements were made of critical shear stress and activation volume as functions of temperature. The study revealed that, for prismatic slip, two overlapping thermally activated processes aye rate-controlling below 300°K. From absolute zero to 220°K, reasonable agreement is obtained between experiment and the mechanism which involves overcoming 01. the Peierl's stress by the formation of double kinks in dislocation lines lying in close-packed directions. Between 220°and 300°K prismatic slip is controlled by a difierent thermally activated process which is characterized by a stronger temperature dependence of critical shear stress. Above 300OK, prismatic slip is controlled by an athermal process. Basal slip is controlled by a thermally activated process between 195' and 400°K. An approximate analysis suggests that it is the Peierl's mechanism that is rate-controlling in this range. Below 195°K, the occurrence of mechanical twinning obscures the features of basal slip. Above '400 X, basal slip is controlled by an athermal process. TITANIUM, an hcp metal with a less-than-ideal axial ratio of 1.587, deforms primarily by {1010}( 1210) slip at low temperatures.'-3 The critical shear stress is strongly affected by the presence of interstitial impurities. For example, churchman3 reported that a decrease in the combined nitrogen plus oxygen content from 0.1 to 0.01 pct decreased the critical shear stress for prismatic slip from 9.19 to 1.4 kg per sq mm at room temperature. Basal slip, however, is less strongly affected by interstitials; Churchman's data for {0001}( 1210) slip show a smaller decrease in critical shear stress from 10.90 to 6.3 kg per sq mm at room temperature, for the same decrease in interstitial content. In the present study, an attempt has been made to delineate the dislocation mechanisms controlling prismatic and basal slip in titanium. In view of the strong effects that impurities may have on at least some of these mechanisms, experiments were performed on material of reasonably high purity, so that comparisons could be made with investigations on material of both lower and higher impurity contents. EXPERIMENTAL PROCEDURE Single crystals were prepared from 1/4-in.-diam electron-beam zone-refined crystal bar, furnished by Materials Research Corp. The analysis of the zone-refined material is given in Table I, indicating that the interstitial content is of the same order as the purer of the two materials investigated by Churchman. The Vickers diamond pyramid hardness number of this material was 85.6. This value agrees quite well with the correlation between hardness and interstitial content proposed by Ogden and Jaffee.4 On the basis of hardness, the material investigated in this study is, therefore, intermediate in purity between that studied by Churchman (Vpn = 97) and that studied by Spangler and Herman (Vpn = 62.4).5 Single crystals were grown by thermal cycling through the a-ß transformation. Two-in.-long by 1/2-in.-diam bars were heat-treated in vacuum for 4 hr at 1160°C. The temperature of the furnace was then lowered to 865°C, and the specimens were maintained at this temperature for 7 days. This procedure was repeated several times, resulting in the growth of individual crystals up to 14 in. in length. Specimens for testing in direct shear along either {l010}(1210) or {0001}(1210) were obtained by electrical-discharge machining. The specimens were in the form of cylinders 1/4 in. in diam by approximately 1/2 in. in length, with a reduced section 1/8 in. in diam and a in. in length. All specimens were electropol-ished subsequent to electrical-discharge machining. The ends of the test specimens were cemented in stainless-steel collars. Shear tests were conducted in an Instron Tensile Tester at various temperatures from 4.2° to 508°K. Measurements were made of critical shear stress and activation volume. The latter measurements were performed by measuring the change in flow stress upon cycling the strain rate between ?1 = 2.62 x 10-3 per sec and ?2 = 2.62 x 10-4 per sec. Activation volume, I)*, is defined as u* =ßkT [11

Jan 1, 1967

By Joseph T. Roy

MINING revival during the last few years has brought about a considerable increase in the number of gold and silver determinations made, noticeable in all branches of the industry but especially so in the business of a custom smelter. At East Helena, solely a custom smelter the assay department found that the four assay furnaces available were inadequate to handle the increased amount of work. These furnaces were of a standard design, having duplex muffles, one superimposed on the other; each muffle was 12 1/2 in. wide, 18 1/4 in. long and 6 in. high, and could handle 72 cupels or 20 fusions. Since the heat varied considerably between the upper and lower muffles, cupellations were not ruin in both at the same time. To speed up assaying, E. A. Meale, chief chemist, had the happy idea of enlarging a muffle furnace, originally designed by the Montana Power Co., so that one muffle would acconmmodate at least as many determinations as the duplex muffles. An order was given to the Denver Fire Clay Co. for a Carbofrax muffle of the size required and the local engineering department enlarged the furnace to accommodate the muffle. Details of the

Jan 1, 1938

Jan 1, 1965

By W. J. Parton

D. R. MITCHELL*—The Chairman mentioned that we have had many papers on cleaning of fine coal and treatment of wash water solids. There are, of course, two reasons for that. One is that we have legislation, particularly in the east. that is making us go into these things whether we want to or not. It just so happens at the present time that I have four plants that are going up under my general direction, three new and one rehabilitation job, and in all of them, we have these problems. Therefore, I was very happy to be able to listen to these papers, because some of the things that are in them are going to help me solve some of the problems that I am facing. Of course, the second reason why we are concerned about fine coal recovery is the fact that coal has become a luxury item in a good many places, particularly in the anthracite region, so that we cannot afford to have it go to waste like we did in former years. There is a third minor reason, and that is that we are finding how to handle and use the extremely fine sizes that we did not know how to use in former years. Now, I have a couple of questions that I would like to ask. First, what are the maximum solids that you could have in a pulp going to one of these launder screens? I realize that it would be for anthracite. Second, of course the life of these screen surfaces is not very long— with brass or bronze, I believe it is a week, and with stainless steel, a month. Would it be possible to use screen surfaces like the Bixby-Zimmer round rod for the small sizes and possibly increase the life? Have you experimented with that? Another point that I would like to bring out, both in Mr. Parton's paper and in some of the others, in studying cyclones and any settling apparatus where we use orifices, the life of the orifices is very short, and that is a problem that still has to be solved. The capacity of the cyclone seems to be small, and if you have a bat-

Jan 1, 1950

By Edward H. Robie

PROBABLY nowhere in the United States or its possessions is mining development more active at present than in the Philippine Islands. Only a few years ago only one company was of any importance, the Benguet Consolidated. Now, five companies are paying dividends, five others have reached the producing stage, some seven others may produce this year, and a score or so are being actively developed. Gold production in 1933 was valued at about $8,000,000, last year at about $11,000,000, and this year an output valued at about $17,000,000 is envisaged. At the beginning of 1934 about 1750 tons of ore was being milled daily; at the end of the year, the tonnage was approximately 3400. In 1933 there were only thirteen Institute members in the Philippines; a year ago there were 27, and now there are 46. About fifteen thousand amen were employed in the mining industry last year, with mine payrolls amounting to $3,500,000. An immense amount of new machinery has been required. One difficulty has so far hindered gold-mine development to some extent-lack of adequate power. Each company therefore finds it necessary to generate its own power, and for this purpose diesel engines are generally adopted.

Jan 1, 1935

By John T. Galey

The outstanding developments of the year in southwestern Pennsylvania were the establishment of the Summit Fayette County gas pool and the gas pool in Nicholson township, Fayette County, and Monongahela township, Greene County, as major producing areas, and the indication of four new shallow gas pools. Curtailment of drilling for shallow gas is expected to follow order M68 of the Office of Production Management. Gas completions were approximately 70 per cent higher, oil completions nearly 25 per cent lower, dry holes were unchanged and drilling wells as of Dec. 31, 1941, nearly loo per cent higher than last year. Shallow Development Oil.—Outside Butler County, only 11 producers were drilled, with a total initial of 221 bbl. The best of these was in a portion of Gilmore township, Greene County, which ordinarily produces gas. This well flowed 77 bbl. in 11 hr., along with about one million cubic feet of gas from the Fourth (U.Dev.) sand. Washington County had a 10.20 and a 25-bbl. well in Morris township and a 20-bbl. well in South Franklin township. These were all in the Fifth Sand. The price of oil to Jan. 27 was $1.80 per barrel, when a 15¢ increase was made. This was followed by a raise of 20¢ on Apr. 23, 15¢ on May 21, 20¢ on June 18 and 25¢ on Aug. 14. The last increase was canceled on Aug. 23 by the Office of Price Administration, which pegged southwestern Pennsylvania crude at $2.40 per barrel. Gas.—An almost doubled initial production of natural gas is the result of the large increase in number of wells drilled. The outstanding discovery of the year was in the vicinity of Armbrust, Hempfield township, Westmoreland County, where a well drilled to what at first was considered the Bayard sand, but what is now known to be the Fifth (U.Dev.) sand, at 2100 ft. found nearly 5 million cu. ft. of gas. Since this completion 14 wells have been finished, only one of which was dry, giving a combined total open flow of approximately 15 million cu. ft. The sand is 35 to 40 ft. thick and the saturation extends through most of that thickness. Rock pressure, which is 1040 lb. per sq. in., is abnormally high. An area of only about one square mile has been proven but some of the 24 new wells drilling as of Dec. 31 will no doubt extend it considerably. This development has taken place in an area heretofore considered to have had little prospect. There were three good wells in other parts of Westmoreland County. One well in Franklin township, which had 12 million cu. ft, of gas in the Fifth sand, was entirely surrounded by dry holes but is still pro- . ducing at a high rate. In Bell township a 1.6 million cu. ft. well was found in the Speechley (U.Dev.) sand and in Washington township the same sand produced 2.7 million cu. ft. with shut-in pressure of 970 Ib. at 2820 ft. This well is offset by two dry holes and one well with a capacity of only 10 M cubic feet.

Jan 1, 1942

By John T. Galey

The outstanding developments of the year in southwestern Pennsylvania were the establishment of the Summit Fayette County gas pool and the gas pool in Nicholson township, Fayette County, and Monongahela township, Greene County, as major producing areas, and the indication of four new shallow gas pools. Curtailment of drilling for shallow gas is expected to follow order M68 of the Office of Production Management. Gas completions were approximately 70 per cent higher, oil completions nearly 25 per cent lower, dry holes were unchanged and drilling wells as of Dec. 31, 1941, nearly loo per cent higher than last year. Shallow Development Oil.—Outside Butler County, only 11 producers were drilled, with a total initial of 221 bbl. The best of these was in a portion of Gilmore township, Greene County, which ordinarily produces gas. This well flowed 77 bbl. in 11 hr., along with about one million cubic feet of gas from the Fourth (U.Dev.) sand. Washington County had a 10.20 and a 25-bbl. well in Morris township and a 20-bbl. well in South Franklin township. These were all in the Fifth Sand. The price of oil to Jan. 27 was $1.80 per barrel, when a 15¢ increase was made. This was followed by a raise of 20¢ on Apr. 23, 15¢ on May 21, 20¢ on June 18 and 25¢ on Aug. 14. The last increase was canceled on Aug. 23 by the Office of Price Administration, which pegged southwestern Pennsylvania crude at $2.40 per barrel. Gas.—An almost doubled initial production of natural gas is the result of the large increase in number of wells drilled. The outstanding discovery of the year was in the vicinity of Armbrust, Hempfield township, Westmoreland County, where a well drilled to what at first was considered the Bayard sand, but what is now known to be the Fifth (U.Dev.) sand, at 2100 ft. found nearly 5 million cu. ft. of gas. Since this completion 14 wells have been finished, only one of which was dry, giving a combined total open flow of approximately 15 million cu. ft. The sand is 35 to 40 ft. thick and the saturation extends through most of that thickness. Rock pressure, which is 1040 lb. per sq. in., is abnormally high. An area of only about one square mile has been proven but some of the 24 new wells drilling as of Dec. 31 will no doubt extend it considerably. This development has taken place in an area heretofore considered to have had little prospect. There were three good wells in other parts of Westmoreland County. One well in Franklin township, which had 12 million cu. ft, of gas in the Fifth sand, was entirely surrounded by dry holes but is still pro- . ducing at a high rate. In Bell township a 1.6 million cu. ft. well was found in the Speechley (U.Dev.) sand and in Washington township the same sand produced 2.7 million cu. ft. with shut-in pressure of 970 Ib. at 2820 ft. This well is offset by two dry holes and one well with a capacity of only 10 M cubic feet.

Jan 1, 1942

By R. E. Ogilvie, J. I. Goldstein

The a and y solubility limits in the Fe-Ni phase diagram have been redetermined at temperatures above 500°C. Both a diffusion-couple and a quench and anneal technique were used. The solubility limits were measured with an electron-probe micro-analyzer. The nickel concentration at the phase boundary is increased below 700°C and the a solid-solubility range is much larger than had been previously measured. The solubility limits are also extrapolated to 300°C. It is suggested that the solubility of nickel in a FeNi reaches a maximum in the temperature interval 400o to 500°C. THE equilibrium diagram has been of great use in the field of meteoritics, where the phase relations between kamacite (a) and taenite (?) in metallic meteorites can be described by means of the Fe-Ni diagram. The study of metallic meteorites by electron-probe microanalysis has cast some doubt on the accuracy of the presently available Fe-Ni diagrams.1, 2 Recent thermodynamic studies of the Fe-Ni system also suggest that the diagram may be in error.3 For these reasons the high-temperature (800o to 500°C) part of the diagram was redetermined. INTRODUCTION The currently accepted Fe-Ni diagram is that of Owen and Liu.4 Above 910°C, there is a region of complete solid solubility, ? (fee). Below 910°C, the a (bee) phase is stable in pure iron. The effect of increasing amounts of nickel is to stabilize the y phase. The phases that form when Fe-Ni alloys are heated or cooled bear little relation to the equilibrium diagram. If an alloy is cooled from the y state and held at a temperature within the a + y field, no evidence has been found for the occurrence of the y - a transformation.5 If the alloy is cooled to low enough temperatures the y phase breaks down into a supersaturated bee phase called a2. In fact, in alloys over 27 pet Ni the y phase is retained at room temperature.6 The a, phase has the same composition as the original y. The temperature at which a2 forms, the M, temperature, has been determined experimentally.' A state of equilibrium can be approached by cooling below M, to form a2 and then reheating the alloy into the two-phase region of the diagram. The y phase will then begin to precipitate out of the a2 phase and grow. The growth of the phase, however, is quite slow. Using the interdiffusion coefficients -Da of Goldstein et al.,8 it is estimated that it takes about 1 year to grow a 10-µ-wide region of ? at 700°C in a 5 pet Ni alloy. Owen and Liu4 used the technique just described to form the equilibrium phases. The phases present were determined by means of X-ray analysis. The accuracy of their diagram depends on the number of alloys available near the phase boundary at a given temperature. In this study two different techniques were used to determine the a/a + ? and ?/a + ? solubility limits. The inherent accuracy of both techniques was greatly improved over that used by previous investigators because the phase-boundary compositions were measured with an electron-probe microanalyzer. PROCEDURE The two methods used to determine the Fe-Ni diagram are the diffusion couple (D.C.) and the quench-and-anneal (Q.+A.) techniques. In the first method, diffusion couples whose diffusion path goes through a two-phase region of the phase diagram were used. A description of the technique used for making the diffusion couples has been described in a previous paper.' After the diffusion treatment a discontinuity in the resultant concentration vs distance profile was measured. The nickel concentrations in the a and ? phases at the interface of the discontinuity are the solubility limits of the a and ? phases in the phase diagram at the diffusion temperature. If the interface com-

Jan 1, 1965

By C. F. Jr. Tolman

IN February 1913, Prof. L. C. Graton and Dr. Joseph Murdoch1 presented to the American Institute of Mining Engineers a notable contribution to economic geology under the title The Sulphide Ores of Copper. The value of the work was recognized by mine operators, and Mr. Graton was assisted in his plan to extend his investigations,. by the organization of a commission to undertake a "secondary enrichment investigation." In this work lie secured the cooperation of the Geophysical Laboratory of the Carnegie Institution of Washington. Their report 2 on the chemical phases of the investigation has just been published. Incidental to investigations 3 carried on in my laboratory by advanced

Jan 2, 1916

By D. F. Coolbaugh

Successful mine exploration requires sound planning and modern exploration techniques, but it also requires perseverance and the right timing. The La Caridad mineral area has been known for over 70 years, but as with many mines, it was not "discovered" until viewed under new economic conditions and exploration philosophies. Present exploration of the La Caridad area began in 1964 and was carried out under a joint Mexican Government-United Nations Project. Detailed exploration was begun by Asarco Mexicana S.A. in late 1968. The geology of the La Caridad deposits conforms, generally, to the "porphyry copper" deposits of Arizona. However, breccias and pegmatites play a very important part in the emplacement of mineralization.

Jan 1, 1972

By M. Duclos, A. Sawatzky

A simple model has been developed which describes the steady-state solute distribution in Ti-H type systems above the eutectoid temperature in the presence of a temperature gradient. The solute distribution is dependent on the shape of the phase boundaries. An interesting result, and one that is not observed at steady state in thermal diffusion below the eutectoid temperature, is the existence of a two-phase region. The heat of transport for hydrogen in a titanium, Q*a, over the temperature range 275" to 650.C is determined to be 4500 * 230 cal per mole. The heat of transport for hydrogen in B titanium, QB* over the temperature range 320" to 590.C is found to be 630 ± 200 cal per mole. It is also shown that thermal diffusion provides a method by which phase bounduries above the eutectoid may be determined in Ti-H type systems. IN modern technology materials are being used at constantly increasing temperatures under greater temperature gradients. Thus atomic migration in metal alloys due to a temperature gradient (thermal diffusion) may in some cases occur to an observable extent. The thermal diffusion of hydrogen in zirconium has in recent years received considerable attention1-' because of the use of zirconium alloys in nuclear power reactors. The thermal diffusion kinetics below the eutectoid (547°C) are fairly well understood. At steady state the solid solution, a, and hydride, 6, phases are completely separated with the hydride precipitating at the lower temperatures. No experimental work has been carried out in the a + B region although Droege4 suggested that a complete separation of the two phases, as observed at temperatures below the eutectoid, might not always occur. In the present investigation a simple model has been used to determine the steady-state solute distribution under a temperature gradient in Zr-H type systems heated above the eutectoid temperature. The solute distribution is shown to be dependent on the shape of the phase boundaries in the constitutional diagrams and several typical cases are discussed. The model has been applied to Ti-H. This system was chosen in preference to Zr-H because of its much lower eutectoid temperature (-300°C as compared with 547.C), thereby reducing experimental errors due to oxidation and hydriding. The heats of transport for hydrogen in the a and B phases of titanium also have been determined since they were required to compare the proposed thermal diffusion model with experiment. THEORY In the presence of a temperature gradient the atomic flux in a single-phase region of a two-com-ponent system of which the atoms of only one component are diffusing is given by:' J = - U\dx + RT3 dx) which can be written as: j-D(dn/dt +Q*n/RT2)dt/dx [11 J - -D\dT + RT2)dx [1] where D = diffusion coefficient, n = solute concentration, T = absolute temperature, R = gas constant, dT/dx = temperature gradient, and Q* = heat of transport. At steady state (J = 0) Eq. [I] leads to the solute distribution: n = noexp Q*/RT where no = a constant depending on total solute content. The heat of transport Q* can be experimentally determined from the steady-state distribution. In the present paper we shall determine the solute distribution in systems having the constitutional diagram exemplified by Ti-H shown in Fig. l.' As shown, N,(T) and NB(T) are the equilibrium solute concentrations in the a and 0 phases at temperature T. Lines AA' and CC' define the region of interest to us. The following assumptions are made: 1) Steady-state conditions prevail. 2) In a single-phase region all points on an isotherm have the same thermodynamic potential so that the composition over an isotherm is uniform. If a two-phase region exists, thermodynamic equilibrium is found only at phase interfaces. However, we assume the component of the concentration gradient along an isotherm to be small so that the composition in each phase is approximately the same as at the interface and is given by the constitutional diagram, Fig. 1. 3) There is appreciable diffusion of only one component. 4) We shall consider only the case where Qa*, QB*, and Qg*, the heats of transport for solute diffusion in the a, B, and 6 phases, respectively, are positive. This has been observed for the thermal diffusion of hydrogen in zirconium3 and titanium.10 We will show that the steady-state solute distribution above the eutectoid is primarily determined by the heats of transport and the temperature dependence of Na(T) and Np(T). It may be quite different from the steady-state distribution below the eutectoid. For example, we will see that, under certain conditions,

Jan 1, 1970

By William G., Pariseau

There are important phenomena in rock and soil mechanics that cannot be explained in terms of theories of homogeneous, isotropic materials. Subsidence of strata about mine openings is an example. In-situ stress measurements in nonisotropic sedimentary, and metamorphic rocks is another. Patterns of joints, faults, fractures, and similar geologic features impart directional mechanical properties to rock masses that are locally isotropic or anisotropic. On the geologic scale, the non-homogeneity of composite rock masses may, in certain instances, be dealt with as homogeneous anisotropy. The mechanics of large rock masses can, therefore, be expected to involve considerations of anisotropy. The source of the anisotropy is not relevant. Once the scale of observation is selected and the material is defined accordingly, the analysis of stress and deformation proceeds without regard to the numerical values of the material constants. There are also important phenomena in rock and soil mechanics that cannot be explained in terms of linear elasticity, theory. For the mechanical description of anisotropic geologic materials capable of de- forming beyond the limit of purely elastic strains, a plasticity theory is required.

Jan 1, 1972

By S. Weinig, E. S. Machlin

THE mechanism of the martensitic transformation has been the subject of a remarkable number of papers in recent years.' Because the task of evaluating all the available theories is a formidable one, the authors will confine themselves merely to the presentation of results of an experimental investigation of the habit orientation, lattice relations, magnitude and direction of average transformation shear strain, and orientation of subband markings for a single variant of the possible habit systems in an 11 pct Mo-Ti alloy. It is hoped that these data will assist in the establishment of a rigorous theory for the mechanism of the martensitic transformation. Experimental Procedure Specimen Preparation: A sample, approximately 1/2 x 1/4 x 1/4 in., was cut from a double arc-melted ingot composed of commercial-process A titanium and high purity molybdenum (nominally, 11 pct Mo). It was capsuled in evacuated Vycor at 10.-3 mm Hg subsequent to a double argon wash and homogenized for 48 hr at 1100°C. After a direct quench into H2O at room temperature, a large-grained specimen resulted, which, by X-ray diffraction and metallographic means, was subsequently shown to be in the body-centered-cubic phase, ß. Two adjacent, approximately perpendicular faces were polished and the ends of the specimen were ground parallel in a V-block. Fiducial lines were inscribed at 45" to the common edge of the polished surfaces in order that they would be perpendicular to the habit traces of the subsequently formed a plates.2 The specimen was then compressed between the ground ends in a Buehler press to stress induce the transformation ß to a'. Experimental Measurements: The habit-plane orientation, the orientation of subband markings, the orientation relation between the parent ß and the product a', and the transformation strain for the same plate were determined. To further establish the nature of the subbands, one surface was repol-ished and etched. The bands in the a' were still visible and were found to be optically anisotropic under polarized light. Back-reflection Laue patterns were obtained from the ß matrix and from a region comprising both a' plates and adjacent ß matrix (a Cu target was used). By superposition of the two X-ray diffraction patterns, it was possible to obtain a tentative orientation relationship between the two phases. This result was confirmed by a pattern taken after the specimen was rotated to make the basal-plane pole of the hexagonal a' phase strike the film. This necessitated cutting the specimen to expose the a' plate in the new position relative to the X-ray beam. Analysis of Experimental Measurements On the basis of the aforementioned X-ray patterns, the orientation between parent and product

Jan 1, 1955

SIR ROBERT HADFIELD, London, England (written discussion*).-We have in the past known so little about tungsten that an important paper such as Mr. Zay Jeffries contributes is most welcome. I have not much personal knowledge on the subject except as regards combinations of iron with tungsten. I put forward the results of my research on natural alloys in 1903,1 and so far as I know the facts there presented still stand. Singular to say, tungsten added to iron affects the electrical resistance less than any other added element. The following tables taken from research work by myself and Sir William Barrett may be of interest.

Jan 10, 1918

By Elmer A. Holbrook

You moderns think of your field of work as "Minerals Beneficiation"; to me it always will be "Ore Dressing." While I would like to talk with you on the future of ore dressing rather than the past, I cannot do this because I started to work in the field some 56 years ago, and my future is behind me. It is trite to remind you that then, in 1900, one out of every 30 high school graduates went on to higher education. Today, the figure is one in every three. So that, while you have a lot more men to compete with, the field of opportunity has expanded even more.

Apr 1, 1956

By V. L., McCutchan

FORM of ore bodies, strength of wall rock, and quantity of water that must be handled differ so greatly in the various districts in which the Corporation operates that a variety of mining methods have to be employed. All are underground, however, with the exception of glory holes at Cerro de Pasco from which siliceous silver pacos ore is obtained. In general, the ors is in many relatively small bodies unsuitable for hulk mining, such as caving or top slicing. The strength of the rock and ore rarely permit open stopes, though shrinkage is successfully used on various veins with strong walls, particularly in, Casapalca. Horizontal cut and-fill and square-set stoping with careful filling are the principal methods employed, with the necessarily higher cost for supplies and labor offset as much as possible by care in the avoidance of dilution. The mines at both Morococha and Casapalca are notoriously wet, and even at Cerro de Pasco the quantity of water was enough to retard deep development until the perfection of electric pumps. In Morococha particularly, the extension of successive levels, first from adits of moderate length, then from shafts and heavy pumping installations on the 750 and 1000 levels, and finally by the 30,564-ft. Kingsmill tunnel, was one of the most difficult and long continued fights against water and resulting heavy ground that is recorded in mining history.

Jan 1, 1945

By Charles T. Holland, David A. Olsen

Considerable work has resulted in the development of a formula by which the strength of coal pillars for an L to T ratio of up to 12 may be estimated. One of the factors involved in this formula is the coefficient of friction between the coal pillar and the adjacent rock with which it is in contact. This paper presents the results of studies on sandstone, limestone, shale and coal and the coefficient of friction between coal and the other three under wet and dry conditions. With the coefficients of friction thus determined and the use of results obtained earlier by Meikle and Holland, it seems probable that coal pillar strength may be more closely estimated. Several investigators1-3 have found that the com-pressive strength of cubical coal specimens can be correlated by an equation such as

Jan 1, 1969

By I. R. Taylor

Union Carbide has recently developed two open- pit vanadium mines in the Wilson Srpings area of central Arkansas about five miles southeast of Hot Springs. The ores from these mines, together with those from a larger vanadium deposit at nearby Magnet Cove, are processed at a new 1600- tpd plant built by the company in the immediate vicinity (Fig. 1). The Wilson Springs vanadium deposits are associated with the Potash Sulfur Springs intrusive, a circular igneous complex which is exposed over an area that is somewhat less than a mile in diameter.1 The complex has a crude ring structure similar to that of the larger Magnet Cove instrusive six miles to the east.2

Jan 4, 1969