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By Paul Bechtner

THE name bentonite formerly was applied solely to a peculiar clay occurring in Wyoming and South Dakota, which was distinguished from other clays by its unctuous feel when wet and the property of swelling in water. In the last decade scientific studies of clay have recognized that bentonite is composed mainly of the clay mineral montmorillonite and the name bentonite has been extended to cover the entire family of clays that have montmorillonite as their chief constituent. Montmorillonite has the chemical formula of A1203-4Si0-xH2O, With Fe203 and MgO replacing part of the A1203. The montmorillonite crystal is an Si-Al-Si clay mineral, being formed of two silicon-oxygen sheets with an aluminum-oxygen sheet sandwiched between them. In contrast, kaolinite-the chief clay mineral of most clays other than bentonite-is Si-Al, one silica and one alumina sheet. The unit crystal of montmorillonite is much thinner than that of kaolinite, with greater surface area. These differences in crystal structure patterns are leading factors in the dissimilar properties and commercial uses of bentonite compared with other clays. Mineralogically, bentonites are 85 to 90 pct montmorillonite with fragments of feldspar, gypsum, calcium carbonate, quartz and traces of other minerals. They vary in color; the widely used Wyoming type is creamy white when dry and a light shade of tan when wet; the low-swelling bentonites of the southern United States and elsewhere are found in many shades of gray, blue, yellow, red, and brown. Pure white bentonites are rarer and generally of the medium or low-swelling type, though there are a few exceptions to that general rule. PROPERTIES Bentonites may be divided into two general classes: (1) those that adsorb large quantities of water, "swelling" greatly in the process, and that remain in suspension in thin water dispersions; (2) those that adsorb only slightly more water than ordinary plastic clays or fuller's earths, do not swell noticeably, and settle rapidly in thin water dispersions. Another distinction is that some varieties of the No. 2 type

Jan 1, 1949

By Andrew Mayer

Early in 1942 National Lead Co. was requested by the War Production Board to construct and operate a plant for the Government to produce magnesium by the ferrosilicon process which had been developed by Dr. E. M. Pidgeon in the laboratories of the Canadian National Research Council. A contract with the Defense PlantCorporation was concluded in May 1942 and Magnesium Reduction Co., a wholly owned subsidiary of National Lead Co., was formed to carry out this project. The capacity of the plant was rated at I0,000,000 lb. of magnesium per year, equivalent to an average production of about 14 tons per day. The Process The process, in brief, is as follows: The raw materials are dolomite and ferro-silicon, 75 per cent grade. The dolomite is calcined, the calcine and ferrosilicon are ground and mixed and the mixture is briquetted. The briquets are charged into tubular retorts of chrome-nickel steel set horizontally in a furnace with the open ends projecting outside the front wall. The retorts are then closed and evacuated. Magnesium is liberated according to then reaction 2(MgOl CaO) + Si = 2Mg + zCaO, Si% It is distilled from the charge and con- densed on a removable sleeve in the throat of the retort. Sodium and potassium, if present, are also liberated, distilled and condensed on a "sodium condenser" in the end of the retort. At the expiration of the distillation period the retorts are discharged and the cycle of operations is repeated. For the rated daily capacity of 14 tons of magnesium there are required approximately 170 tons of dolomite, equivalent to about 85 tons of calcine, and 16.5 tons of ferrosilicon. The retort residue, a bulky powder which at present is waste, amounts to about 87 tons. Choosing the Site The investigation to select the location of the plant was conducted by the Research Laboratories of National Lead Co. This work included geologic and economic surveys of a number of districts, examination of dolomite samples by chemical, spectrographic and petrographic methods and large-scale tests of dolomite from several of the more promising localities. in the last-named tests 2-ton samples were put through the ferrosilicon process in the pilot plant of the Canadian National Research Council, under the guidance of Dr. Pidgeon. The conclusions drawn from the investigation, in regard to the quality of dolomite to be used in the ferrosilicon process, were: First, the dolomite should contain not less than 21 per cent MgO and not more than 2 per cent acid-insoluble material. Second, the dolomite should

Jan 1, 1944

By M. P. Tixier, K. S. Kunz

A method for the interpretation of temperature curves recorded in gas producing wells is described. One essen-tial feature of the method is a simple graphical construction which conveniently reflects the amount of gas flowing from a given producing formation. This method, applied in conjunction with the Induction Log and radioactivity logs, is valuable to determine the points of entry of gas and to estimate the over-all thickness of the producing zones and their respective contributions to the total production. The method in particular is helpful in evaluating the effect of fracturing operations. An outstanding result of the application of the method is to bring to the light the relative importance of sand-shale interfaces in the production of gas. The paper is illustrated with field examp1es. INTRODUCTION The electrical logging tools involving conventional systems are not applied in wells which do not contain water base mud (empty holes, or wells filled with oil base mud), because of the absence of electrical connection between the electrodes and the surrounding formations. It is, therefore, common practice in this case to use other methods which do not require the presence of a conductive fluid in the borehole: resistivity log with scratcher electrodes, Induction Log, radioactivity logs, temperature log. . . . Such conditions are encountered in some regions, as the San Juan Basin, N. Mex., where a technique of drilling gas wells, using gas as a drilling fluid, has been introduced in the last two years. By the middle of 1953, an appropriate method for the logging of these wells was devised on the basis of field tests and of theoretical studies. It is the purpose of the present paper to give a description of this method. In these wells the logging operations are performed during the process of gas production, so that the temperatures in the boreholes are strongly affected by the cooling due to the expansion of the gas. On the other hand, a special thermometer, with a high sensivity and a short time constant, has been recently made available, which has enabled much more detailed and accurate recordings of the borehole temperatures than with the conventional instruments. As a result of these two circumstances, the temperature log constitutes the essential element of the method, in making possible the detection of the gas producing zones, the definition of their boundaries, and the estimation of the respective contributions of each separate zone to the total production. The method also involves the radioactivity and Induction Logs, as auxiliary documents. These logs in the present instance are helpful in the determination of the reservoirs. However, the information they give in this respect is limited. This comes from the fact that, due to the absence of the MicroLog and/or MicroLaterolog and of the SP log, the estimation of formation factors and connate water salinities is somewhat conjectural. Furthermore, little help is obtained from the Neutron log for the evaluation of porosity and of formation factor because the variations of gas saturation affect the Neutron log in a way similar to the variations of porosity. It should be said also that even an exact knowledge of the gas saturation of the reservoir beds would not

Jan 1, 1956

Discussion o f Papers. Meetings of the Institute offer opportunity for social acquaintance and exchange of ideas, for the--presentation of papers, and-for discussions. thereon ; also incidentally for viewing under especially favorable conditions mining operations and industrial establishments, and for hospitalities which demonstrate the brotherhood clue to kindred interests. Placing sociability prominent is not to be assumed as relegating other features of meetings to subordinate positions; but during about 40 years of membership in the Institute, the value of acquaintances formed (often ripening into close friendship), and the interchange of data, have frequently demonstrated that the social feature of meetings is of great and lasting value to the membership. Of a roll embracing 4,011 members, resident in all parts of our country, and scattered in various portions of the world, only a small fraction are able to attend meetings, even if the localities selected are alternately widely separated. Hence, the return which most members receive for their annual assessment of dues is limited to the publications issued, and the credit of being recognized as a. member of a great and worthy organization. The greater the value of the contents of our publication, the fuller the return which goes to members. While the Institute disavows responsibility for views or statements made ill papers which appear in its Transactions, the fact that these contributions, after passing proper censorship, are accepted by the Institute and spread before the world may properly be received by the writers as endorsements of their (the writers') ability to present a specific technical or industrial proposition worthy of being carefully read. But the mere presentation and publication of contributed papers falls short of fulfilling one important feature of our meetings. If the purpose is confined to having the writers' views, discoveries, theories, or methods published, this can be obtained through the technical or trade journals and magazines. The true value of a paper presented at a meeting of the Institute may often be gauged by the discussion which it encourages, although there are contributions of decided value which do not especially invite discussion. However, most Of the papers offered contain statements apt to encourage criticism or elaboration by others whose experience or knowledge, or both, assist in combating or endorsing statements made.

Jan 7, 1913

By C. E. Berner

Since 1933, the Coal Mine Rating Schedule in Pennsylvania has provided credits in the Workmen's Compensation insurance premium rates for the use of safety hats, goggles and shoes. In that year, the worth of such protective clothing had just been well established and satisfactory articles were being made by a number of manufacturers. Standards for these three items of safety clothing' were written in the Rating Schedule and have been little changed through the years. The credit in the premium rate for a bituminous mine is $0.14 for hats, $o.08 for goggles, $o.08 for shoes. In order to earn such credit, it is necessary that all the employees in the particular mine be equipped with safety hats, goggles or shoes, as the case may be. In fact, it is not unusual for mines to qualify in all three categories, thus earning a rate reduction of $o.30 per $100 of payroll. These credits have been a decided stimulus to the use of safety clothing, and at present insured bituminous mines are credited as follows: Hats........ 63 per cent, or 22,600 employees Goggles..... 28 per cent, or 10,000 employees Shoes....... 44 per cent, or 15,800 employees Of course, many other employees wear these protective articles but they are in mines that are not fully equipped and so are not given the rate credit. The growth in use of this equipment has not been spectacular but it has been steady, as shown in Table I. An interesting thing about this is that it covers virtually all of the small and medium-sized bitumi- nous mine operations in Pennsylvania. A number of large operations are included, but many large mines are self-insured. It is difficult to keep alive interest in safety work in the smaller mines: first, because employment of safety engineers is out of the question and the one or several mine officials employed are often concerned only with production; second, because the life of many small mines is brief, so that safe conditions although established do not last long. Conditions as to safety in mines of this class rest chiefly with inspectors of state mine departments and of casualty insurance companies. Many millions of tons of production come from these mines, so that

Jan 1, 1944

By C. E. Berner

Since 1933, the Coal Mine Rating Schedule in Pennsylvania has provided credits in the Workmen's Compensation insurance premium rates for the use of safety hats, goggles and shoes. In that year, the worth of such protective clothing had just been well established and satisfactory articles were being made by a number of manufacturers. Standards for these three items of safety clothing' were written in the Rating Schedule and have been little changed through the years. The credit in the premium rate for a bituminous mine is $0.14 for hats, $o.08 for goggles, $o.08 for shoes. In order to earn such credit, it is necessary that all the employees in the particular mine be equipped with safety hats, goggles or shoes, as the case may be. In fact, it is not unusual for mines to qualify in all three categories, thus earning a rate reduction of $o.30 per $100 of payroll. These credits have been a decided stimulus to the use of safety clothing, and at present insured bituminous mines are credited as follows: Hats........ 63 per cent, or 22,600 employees Goggles..... 28 per cent, or 10,000 employees Shoes....... 44 per cent, or 15,800 employees Of course, many other employees wear these protective articles but they are in mines that are not fully equipped and so are not given the rate credit. The growth in use of this equipment has not been spectacular but it has been steady, as shown in Table I. An interesting thing about this is that it covers virtually all of the small and medium-sized bitumi- nous mine operations in Pennsylvania. A number of large operations are included, but many large mines are self-insured. It is difficult to keep alive interest in safety work in the smaller mines: first, because employment of safety engineers is out of the question and the one or several mine officials employed are often concerned only with production; second, because the life of many small mines is brief, so that safe conditions although established do not last long. Conditions as to safety in mines of this class rest chiefly with inspectors of state mine departments and of casualty insurance companies. Many millions of tons of production come from these mines, so that

Jan 1, 1944

By T. S. Lovering

An economic geologist is concerned primarily with finding deposits of economic value, estimating their tenor and quantity, their shape and position. Thus the primary problems can largely be lumped under three headings: position, character and quantity; and all three are phases of the broader problem of genesis. Distribution, tenor and quantity are of immediate practical importance and are studied constantly by all who exploit mineral deposits. Although the emphasis changes from year to year, the problems of genesis seem more remote and rarely get the serious consideration from the field man that the other three do. Our understanding of the problems of the genesis of mineral deposits has come largely as a by-product of more evidently utilitarian work in the past, and probably will continue to grow in the same manner lor many years to come. However, it might be economically fruitful for the producers to have many competent investigators spending their time chiefly on the problems of genesis of mineral deposits. Many years ago, when first engaged in work for the United States Geological Survey in Colorado, I expressed a conviction which was just then dawning on me by saying that economic geology was turning out to be 80 per cent structural geology, to which Mr. B. S. Butler replied, "Yes, and more than 80 per cent of structural geology is lithology." At the present time there seems to be a widespread feeling among economic geologists that the problems of position or distribution are largely problems of structure and rock types. Types of Research Ptesearch in any branch of geology can be conveniently divided into two types: field research and laboratory research. Ideas are usually dug up in the field, pruned or developed in the laboratory, and taken back to the field for proving. For either the first or last step the field data should he as complete as possible, and the structural geology of nearly all our mineral deposits still needs more detailed delineation. In general, this means mapping on larger seales. Ideally the structural map should give a factual picture of a11 visible effects of stress; there is still room for vast improvement in the technique of presentation. Information that is much

Jan 1, 1940

By T. S. Lovering

An economic geologist is concerned primarily with finding deposits of economic value, estimating their tenor and quantity, their shape and position. Thus the primary problems can largely be lumped under three headings: position, character and quantity; and all three are phases of the broader problem of genesis. Distribution, tenor and quantity are of immediate practical importance and are studied constantly by all who exploit mineral deposits. Although the emphasis changes from year to year, the problems of genesis seem more remote and rarely get the serious consideration from the field man that the other three do. Our understanding of the problems of the genesis of mineral deposits has come largely as a by-product of more evidently utilitarian work in the past, and probably will continue to grow in the same manner lor many years to come. However, it might be economically fruitful for the producers to have many competent investigators spending their time chiefly on the problems of genesis of mineral deposits. Many years ago, when first engaged in work for the United States Geological Survey in Colorado, I expressed a conviction which was just then dawning on me by saying that economic geology was turning out to be 80 per cent structural geology, to which Mr. B. S. Butler replied, "Yes, and more than 80 per cent of structural geology is lithology." At the present time there seems to be a widespread feeling among economic geologists that the problems of position or distribution are largely problems of structure and rock types. Types of Research Ptesearch in any branch of geology can be conveniently divided into two types: field research and laboratory research. Ideas are usually dug up in the field, pruned or developed in the laboratory, and taken back to the field for proving. For either the first or last step the field data should he as complete as possible, and the structural geology of nearly all our mineral deposits still needs more detailed delineation. In general, this means mapping on larger seales. Ideally the structural map should give a factual picture of a11 visible effects of stress; there is still room for vast improvement in the technique of presentation. Information that is much

Jan 1, 1940

By Howard S. Bryant

The state of Kansas in 1931 continued to hold fourth place on the list of oil-producing states, despite the fact that low prices for crude oil curtailed drilling to just one-half the amount done in 1930, which itself was the lowest in the preceding 10 years. The estimated crude oil production for 1931, according to sources available to the writer, will approximate 37,037,000 bbl., the lowest since 1925. Thus Kansas produced one-eighth less oil this year than it did last year when it produced 42,729,085 barrels. This year's development was characterized by a very small amount of wildcat drilling; however, large new areas were semiproven for oil production, and several thousands of acres were added to the actually proved areas in western Kansas, so that the state now has larger proven areas of oil reserves than at any time in its history since the heyday of the famous El Dorado pool. The general prospects for oil production in the near future are indeed promising for central western Kansas, where drilling costs are moderate and depths are relatively shallow compared to the remaining unexplored parts of the northern Mid-Continent area. Probably the greatest singular achievement in the state for 1931 was the development of its natural gas reserves. This development took place principally in two spots, McPherson County in central Kansas, and Stevens and Morton counties in southwestern Kansas, and it is a matter of record that more than one and one-half billion cubic feet of open-flow capacity per day were added to reserves, nearly twice the amount developed in 1930, previously the largest amount in the history of gas development in Kansas. Gas pipe lines already built and now building are in position to deliver natural gas by one system to Chicago, Ill., by another to Indianapolis, Ind., from whence lines already lead practically to the Atlantic seaboard, and to other cities large and small located west, northwest, north and northeast of Kansas. Table 2 shows all well completions for 1931 in a form to compare with the results of previous years.

Jan 1, 1932

By E. A. Koester

Kansas produced approximately 35,434,000 bbl. of oil in 1932 compared to 37,018,000 bbl. in 1931, a decrease of 1,584,000 bbl. or 4.2 per cent. These figures do not indicate the amount of oil that could have been made available from the state for the year. Many of the fields discovered during the year and some discovered in previous years were entirely shut in. Practically all flush production discovered within the last two years has been prorated in some manner or other. Probation Kansas production is under regulation as specified in House Bill 387, passed by the legislature in 1931, which became effective when published May 28, 1931. The principal features of the law are the prohibition of waste, including gas energy, the regulation and prevention of discrimination of purchasers, the marketing of oil ratably from wells in each field when the daily production is above 15 bbl. per well. This act gives the enforcing powers to the Public Service Commission. The Commission, having many other regulatory duties, appointed an Oil Advisory Committee, which, with the aid of the State Umpire, keeps records and makes recommendation for orders as to specific regulation of fields and conditions in each field. At the time the Commission was given authority to regulate production and marketing in flush fields, several of these had already been under voluntary proration and marketing restrictions by agreement of the operators. These gradually came under the control of the Commission by mutual consent. It is the policy of the Public Service Commission to follow the will of the operators so long as they do not have ideas or plans in conflict with the law. The cost of administration of this law is assessed against the operators according to the amount of oil taken from the fields in which ratable taking is necessary. There is a feeling that the whole state should share this expense, which is small, since it is beneficial to the older fields by assuring them 100 per cent market for their output by restricting the flush fields.

Jan 1, 1933

By H. J. Wasson

At the close of 1927 Venezuela was producing at the rate of 205,000 bbl, per day, making it the third country in the world in point of present daily production. For the year, the total was close to 64,000,000 bbl., representing an increase of about 70 per cent. over the 37,000,000 bbl. in round numbers produced in 1926. All of the 1927 production canie from fields opened up before the beginning of the year. While no new fields were added to the list of shippers, the past 12 months' wildcatting yielded a fair quota of new discoveries which, in the light of prcsent results, may be considered likely sources of production in due time. Altogether three such promising finds were made Of first importance, at least for the immediate future, is the completion by the Lago Petroleum Corpn. of the San Matins well, 4 miles north of the present edge of the Lagunillas field. Although rated as only a 125. bbl. well, at 3217 ft., it indicates a probable extension of the field over the intervening 4 miles between the two. The two other wildcat discoveries of importance were the Los Manueles well in the District of Colon, which has in all probability opened up a new field about 7 miles north of the present Tarra oprations; and the Honibre Pintado well of the Standard Oil Co. of Venezuela,. in the State of Falcon, which is considered to be a promising clc~vc~lop~ncnt. Neither of these last mentioned two discoveries will apprcciably affect production during 1928, as the Manueles area must await the carrying out of a general plan for the exploitation of the District of Colon, a problem requiring time. The Hombre Pintado area is being tested further, but doubtless several wells will be put down before. anything definite will be done towards making the pipe line. arrangements that rnust necessarily precede the commercial exploitation of the field. The San Matias Well The San Matias well is a highly significant dcvelopment,. It is located along the trend of the La Rosa-Ilagunillas producing formations, and when drilling started, production in the Lagunillas field was 4 miles

Jan 1, 1928

By H. R. Barnhurst

It would be a difficult matter to trace from the beginning the very few improvements made in the burning of fuels prior to 1860. Donbtless the crossing of the sticks of wood in building a mood fire early appealed to our savage ancestry as a means of expediting its effectiveness for their crude culinary purposes. Stones and andirons came later in assisting the admission of air to the under part of the fuel bed, while beacons and cressets, utilized metal bars as supports for the same purpose. It is probable that Tuba1 Cain owed his success to the use of bellows making possible the use of mixed fuel and charge upon a hearth. With the development of working in cast iron, grate bars came in, and they are still with us doing duty in every household and almost every art where heat is a factor. Little was done beyond these crude methods prior to 1860. With the advancement of knowledge came the fuel-gas producer, a natural child of the retorts employed in supplying illuminating gas. It is only within the last 15 years that the conclusion became general that complicated systems for saving heat would not remedy deli-. ciencies in its primary development, and within that time there has been great advancement in the means of producing initially a fire of high effciency, so that to-day we are moving rapidly toward both high development and high absorption, with the resultant of high efficiencies. In studying the subject of the availability of pulverized coal as a fuel, it may occur to ask, why has this not come up earlier? This, question would be naturally prompted by recalling the fact that Thomas Crompton's English patents upon his methods were issued to him nearly 40 years ago. A conclusive answer to this, however, is that Crompton at that time had very crude facilities for making what was at best a very imperfect pulverization of the coal, arid the expense of preparation mas very great. He does not seem to have been aware of the advantage of a thorough drying of the coal in the

Jan 1, 1914

By W. H. Brandt

ThEre has been much progress in the last two decades in understanding the hardenability of steel. Roughly, the progress has been along two lines, which may be designated as empirical and fundamental. This empirical work has progressed to the point where steels may be manufactured to the desired characteristics quite closely and heat-treatment and application problems can be approached with considerable confidcnce. Particularly noteworthy among the empirical work is that of Grossmann,12. who has given formulas for calculating hardenability as a function of composition, and the establishment of the isothermal transformation curve by Davenport and Bain.13 The latter does not fall entirely in the class of an empirical study, for while it provides a means of presenting a tremendous amount of empirical data in the form of a single curve, it also outlines clearly the problems that face the fundamental investigator. The isothermal transformation curve shows clearly that the phenomena occurring in the neighborhood of the knee of the curve are those that limit the hardenability of steel. Above the knee of the curve, the product of decomposition of austenite is lamellar pearlite and fundamental progress has consisted chiefly of a detailed study of structure and formation of pearlite, largely at the hands of Mehl and his collaborators.'-5 They have shown that formation of pearlite proceeds by a process of nuclea-tion and growth and they measured both the nucleation and growth rate. However, there is still a wide gap between our empirical knowledge and fundamental knowledge, owing largely to the fact that there is no satisfactory theory of nucleation rate or of growth rate. This paper is being written in an attempt to Hl in a small part of the gap. A method was prcsented recently1' for calculating the velocity of edgewise growth of pearlite using an expression for the carbon concentration that satisfies the diffusion equation. The edgewise velocity of pearlite growth in a plain carbon eu-tectoid steel was calculated, using linear extrapolations of the ferrite and comentite solubilities. While the results are in fairly good agreement with the experimental facts, the calculated velocity of edgewise growth is smaller at 600°C. than G, the radial growth velocity of pearlite nodules, whereas one would expect it to be larger. In this paper the calculation will be repeated using a new extrapolation for the ferrite solubility, which gives better agreement between G and T', the calculated velocity of edgewise growth. A calculation will also be made of the effect of carbon content on velocity of edgewise growth, and the problems of calculating the effects of other alloying elements on growth rates will be discussed. It will be assumed that the mechanism of pearlite growth, established by Mehl and

Jan 1, 1947

By W. H. Brandt

ThEre has been much progress in the last two decades in understanding the hardenability of steel. Roughly, the progress has been along two lines, which may be designated as empirical and fundamental. This empirical work has progressed to the point where steels may be manufactured to the desired characteristics quite closely and heat-treatment and application problems can be approached with considerable confidcnce. Particularly noteworthy among the empirical work is that of Grossmann,12. who has given formulas for calculating hardenability as a function of composition, and the establishment of the isothermal transformation curve by Davenport and Bain.13 The latter does not fall entirely in the class of an empirical study, for while it provides a means of presenting a tremendous amount of empirical data in the form of a single curve, it also outlines clearly the problems that face the fundamental investigator. The isothermal transformation curve shows clearly that the phenomena occurring in the neighborhood of the knee of the curve are those that limit the hardenability of steel. Above the knee of the curve, the product of decomposition of austenite is lamellar pearlite and fundamental progress has consisted chiefly of a detailed study of structure and formation of pearlite, largely at the hands of Mehl and his collaborators.'-5 They have shown that formation of pearlite proceeds by a process of nuclea-tion and growth and they measured both the nucleation and growth rate. However, there is still a wide gap between our empirical knowledge and fundamental knowledge, owing largely to the fact that there is no satisfactory theory of nucleation rate or of growth rate. This paper is being written in an attempt to Hl in a small part of the gap. A method was prcsented recently1' for calculating the velocity of edgewise growth of pearlite using an expression for the carbon concentration that satisfies the diffusion equation. The edgewise velocity of pearlite growth in a plain carbon eu-tectoid steel was calculated, using linear extrapolations of the ferrite and comentite solubilities. While the results are in fairly good agreement with the experimental facts, the calculated velocity of edgewise growth is smaller at 600°C. than G, the radial growth velocity of pearlite nodules, whereas one would expect it to be larger. In this paper the calculation will be repeated using a new extrapolation for the ferrite solubility, which gives better agreement between G and T', the calculated velocity of edgewise growth. A calculation will also be made of the effect of carbon content on velocity of edgewise growth, and the problems of calculating the effects of other alloying elements on growth rates will be discussed. It will be assumed that the mechanism of pearlite growth, established by Mehl and

Jan 1, 1947

By W. Tovote

This paper is based upon 12 years' experience in the Southwest, including three years that were spent in constant traveling as examining engineer for the Phelps-Dodge Corporation. The material was gathered during rather extensive work in Bisbee, Clifton-Morenci, Globe, and Tombstone, and also on short and rapid trips into most of the mining camps and prospect fields of New Mexico, Arizona, the desert country of California, and as much of Sonora as was safe at the time. My methods of observation and my deductions are not put forward as new or scientific; they are simply rough field methods, based upon short notes, rough sketches, and largely upon memory, which I have found useful for coördinating geological data for the purpose of passing quick judgment on mining possibilities in certain districts exhibiting uniform characteristics. The opportunities for observation have been better these last few years than ever before, due to the unprecedented activity in mining, which has caused the reopening of hundreds of old mines and the starting of even more numerous prospects all over the mining states. Possible Systems of Classification By Geological Provinces There are a number of well defined geological provinces in the territory under discussion, and a study of their individual features is of interest. The following are a few of those that are most striking in their uniformity. 1. The "Desert province," extending roughly from Wickenburg, Ariz., to and beyond Barstow, Cal. In its north-south extent it reaches up to the Colorado River and down into Sonora, but overlaps other provinces. It is characterized by a worn-down basement of schistose and granitic rocks, on which rest remnants of Paleozoic and pre-Paleozoic sediments, including very old limestones. The sediments are disrupted and contorted. Alteration in the mineralized areas is very prominent, especially in the schists and limestones. Cenozoic volcanic rocks, principally of semi-basic composition, have been intruded into this complex and sometimes cover it as lava flows. 2. The "Yavapai schist" province, similar to the one first mentioned, consists of metamorphosed basic and semi-basic rocks. It lies in northern

Jan 1, 1920

During the year this Committee has had the benefit of the services of 75 Committee members, resident in the various States of the Union and in foreign countries, 10 of them representing us abroad. A number of plans for awakening the interest of possible new members have been carried out and the results have been very gratifying. The comparative results for 1913 and 1914 are as shown in the following table: 1913 1914 Applied for membership 630 946 Elected 450 1,006 Accepted election 433 921 When it is remembered that the depression following the outbreak of war in Europe has had more serious effect on the mining industry than almost any other, these results cannot be regarded as anything other than very encouraging. Because of the unsatisfactory conditions still prevailing it will doubtless be difficult to make even as good a showing next year. It is considered, however, that the function of this Committee is not merely to secure new members, having no regard for other than numbers; its true function is to exercise a proper supervision over the growth of the Institute, building it up in those fields in which it is weak, and directing its growth in such a way as to make it most effective in fulfilling its proper function as the national organization representative of the mining profession. The plan of inviting the alumni of the leading mining schools to apply for membership, which was initiated last year, was completed this year, with the exception of one or two schools, notably the University of California, from which we have not been able to obtain a list of alumni. With these exceptions we have now extended to the graduates of all the important mining schools of this country, and several of those abroad, an invitation to apply for membership in the Institute. It. is not thought desirable to repeat this invitation too frequently, and it is therefore suggested that this field be left alone for a year or two, when, if the mining industry experiences a marked revival of interest, it will be well to send out a second letter to the same men.

Jan 4, 1915

By James F. Magee

There is nothing new about dragline dredging for placer gold. The use of the separate unit for excavating preceded the large barge with excavator mounted upon it, which has reached a high state of perfection through use in every part of the world. But at present there is a vogue for a small, inexpensive plant combining a dragline excavator on caterpillar mounting and a gravel-washing plant on a floating barge. The most efficient ones use a bucket of 1 to 2 yd. capacity with boom from 40 to 70 ft. long. The barge varies from 20 by 30 ft. to 36 by 48, and carries the trommel screen, pump, riffle sluices and power engine. Plants in Oboville District In the Oroville district eight such plants have been built since 1933, and have been operated with varying success. The most successful of these is the plant of the Wyandotte Gold Dredging Co. This organization of six active partners constructed its first plant on Wyandotte Creek in the autumn of 1933. To September of 1935 about one million cubic yards of gravel was dredged for an output of about $225,000 in gold. The operation has been successful from the beginning, because of wise management, which was based upon good plant design and proper principles of operation. All the partners have taken a more or less active part in the operation. Usually there is one at work on each shift, and they have conducted their own prospecting and building also. They elected H. F. England as manager, with wide power of control, and he carries out this responsibility energetically and successfully. One of the other plants, started shortly before the Wyandotte, finally abandoned its operation and sold its ground to the latter company, which successfully worked it for a profit. The failure of the other plant was due principally to poor excavating equipment. Another organization that built a plant some months later than the Wyandotte company had considerable difficulty in management and was unable to keep ahead of expenses. Finally, late last summer, it entered into an agreement with the Wyandotte company to have the latter supply

Jan 1, 1937

Butte Meeting. It is expected that the technical program of the Butte meeting will be a sufficient attraction to draw to that point every member who can possibly get away long enough to attend. Attention is particularly called to the papers already sent in by the Committee on Precious and Base Metals, and the papers which they are undertaking to secure for the meeting, as published on pp. ix and x. In addition to these papers, and in addition to those published in this Bulletin, the office of the Institute already has in hand several papers, which will be published at an early date, and presented in abstract and discussed at the meeting. Of the discussion of these papers a special feature is being made. Therefore, let every member come to Butte who can do so. A meeting of the Board of Directors of the Institute will also be held at Butte. In the May Bulletin, we stated for the information of members the railway excursion rates for two suggested tours in connection with the meeting, which included Glacier Park before the meeting and Yellowstone after it. The itineraries there given and rates quoted were planned and offered by the railway agent bureaus in New York. Circulars have been sent to the members of the Institute by A. E. Vaughan & Co., a tourist trip agency of New York City, containing details of tours nearly identical with those outlined in the Bulletin, and quoting rates covering, the expenses of the whole trip. Members can easily compare these rates with the rates offered by the railroads, and published in the last Bulletin. In order that no misapprehension may exist, the statement is here made that the Institute and its officers have no connection whatever with Vaughan & Co.'s proposals and that any such tours will be strictly personal matters between said company and the members of the Institute who take them. Nevertheless, the Board of Directors calls to the attention of members the circumstance that tours such as these will afford an opportunity for members to travel together to the meeting.

Jan 6, 1913

By Thomas R. Cunningham, A. B. Kinzel

Silicon, unfortunately, is not in the same category as some other metals with respect to the absolute value of the highest purity material prepared. Tucker, in England, and Becket, in this country have developed procedures for the purification of silicon, and Becket's process has made industrially available silicon of a purity of 99.8 per cent or better. However, even the term "silicon metal" may be a paradox to some people, although not more so than the term "amorphous" as applied to silicon. These terms come from commerce, and "metal" is used to distinguish industrially high-purity silicon from ferrosilicon, silicon-aluminum, and other high-silicon alloys. Alloys of iron and silicon with 95 per cent Si or less are known as ferrosilicon, with a designation of silicon content where necessary, arid the term "silicon metal" is invariably applied to the grades containing 96 per cent Si and higher. The Becket method of purification was referred to in a monograph on the Alloys of Iron and Silicon, and the Tucker procedure was described in some detail in that publication.' In order to get silicon of still higher purity, a sample, prepared by the Becket method, analyzing 99.84 per cent Si, 0.020 Fe, 0.016 Al, 0.005 Ca, 0.025 C, 0.033 per cent 02, 0.006 H2, 0.006 N2, and 0.001 per cent Mn, was crushed to pass a 100-mesh sieve and further purified by a modification of Tucker's procedure. This modification differs from Tucker's method in that after treatment the 100-mesh alloy was centrifuged to remove the last traces of acid. Our directly determined analysis of this purified sample shows: Si, 99.952 per cent; Fe, 0.009; Al, 0.012; Ca, 0.003; C, 0.006; or 99.982 per cent. Silicon by difference equals 99.97 per cent. The variation between silicon by difference and silicon as directly determined is important. Although Tucker mentions the amount of insoluble matter in commercial silicon both before and after his treatment, he does not mention the existence of carbon in the alloy; nevertheless, he reports silicon by difference. Any final figure as to purity obviously results from agreement between direct determination and

Jan 1, 1940

By Barnabas Bryan

In the year 1875, the Pennsylvania Supreme Court, acting on incorrect information concerning the production of oil and gas, established what has become the law of the land for the governing of oil production. While the decision was ideal for the refining monopoly which was completed in that year, there is no evidence that the court was in any way influenced by that refining monopoly. The evidence indicates that the court accepted the view of the royalty owner and independent oil producer. Throughout the life of the refining monopoly it accepted this law, which was so evidently to its advantage in securing cheap raw material. The same policy continued until the development of the exhaustion theory and the entry of the various units of the former monopoly into the production of crude oil. It is curious that no one doubted the new theory of shortage sufficiently to feel the need of changing the law. When the theory entered the economic field sufficiently to raise crude oil prices beyond justification it shortly disproved itself, but by this time the question of split ownership in producing fields made a change from legal error to justice too complicated to be undertaken by the large companies. Not even the ardent advocate of unit operation dared to carry the question to the United States Supreme Court, which has never been asked to pass on the complete question. The impossible position of the producing industry, hemmed in on one side by court law compelling wasteful production and on the other by the national law against cooperation, lasted until the demoralization of 1927 led to cooperation within a state and under state guidance. Since that time control of production has grown with the bringing in of each new field and at this time has the active support of the Department of the Interior in such ways as are definitely legal. As in 1875, the royalty owner and independent producer are opposing by all possible means the rational conduct of the business of producing crude oil. Fluctuation in Investments The investor in oil securities has not been as badly fooled as has the oil man himself. Fig. 1 is designed to show the composite regard of all

Jan 1, 1930