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By Stuart M. Buck, J. H. Bramwell, Edward H. Williams

The Southwest Virginia Improvement Company began operations in the Bluestone Flat-Top coal-field, situated in Tazewell County, Virginia, in the fall of 1881. In May, 1883, the company had built 200 coke-ovens, and by March, 188-1, had 9000 feet of entries, exclusive of air-ways, in the Nelson or Rig coal-bed of this district (which here averages eleven feet in thickness), and had extracted 200,000 tons of coal, representing an area of about twenty acres. About this opening has grown the recently incorporated city of Pocahontas, and the completion of the New River branch of the Norfolk and Western Railroad to this point enabled the company to make large contracts for supplying coal and coke, so that it was deemed necessary, on account of the limited area developed, to work the mine day and night to fill orders. At 1.30 Thursday morning, March 13th, the inhabitants of Pocahontas were awakened by a violent shock, and within a few minutes all knew that the East mine had been the scene of an explosion of so general a nature that, of the 114 men at work, not one had escaped. The daily papers gave more or less distorted accounts of the number of victims, the scenes in and about, the mine, and the probable cause of the disaster. At the request of the company, the President of the American Institute of Mining Engineers appointed the undersigned a committee of three to investigate the matter, and the committee thus constituted presents the following report, accompanied by a copy of the testimony taken daring the investigation, for preservation in the archives of the Institute. Pocahontas was reached on Thursday, April 24th, and left on Friday, May 2d. During this interval the committee made repeated visits to the mine, especially to the points, of most importance, examining it carefully in every part; and summoned a number of witnesses, twenty-six of whom appeared and testified. The mine had been left in the same state as when the bodies were

Jan 1, 1885

By Walter S. McKee

Discussion of the paper of WALTER S. McKEE, presented at the New York meeting, February, 1916, and printed in Bulletin No. 108, December, 1915, pp. 2399 to 2411. J. W. RICHARDS, So. Bethlehem, Pa.-I regret that the author has overlooked the great usefulness of the electric furnace for the melting of ferromanganese in the manufacture of manganese steel. WALTER S. MCKEE, Chicago, Ill. (communication to the Secretary*)-In an article as brief as mine it was not possible to .fully cover the metallurgical field; this accounts for my not mentioning the electric furnace for the melting of ferromanganese in the manufacture of manganese steel, although the advantages of such an apparatus are fully appreciated by me. FREDERICK LAIST, + Anaconda, Mont. (communication to the Sec-retary?).-Manganese steel has proved very serviceable in our plant.. We are using manganese steel for the jaw plates on the 5-' by 15-in. crushers in the concentrator instead of cast-iron jaw plates which we formerly used. The manganese steel wears five times as long as the cast iron. We are also using manganese steel in our 8- by 20-in. crushers. In our primary crushers, which are 12 by 24 in., we still use cast iron because the manganese-steel plates wore unevenly and left shoulders which caused trouble in setting up the crusher. Another reason for preferring cast iron in these crushers is that they grip the ore better on account of wearing of the rougher surface. The surface of the manganese steel becomes polished and large pieces of ore fail to be drawn in. We recently tested 8- by 16-in. manganese-steel elevator buckets working on 2-in. undersize against malleable-iron buckets and found that manganese-steel buckets lasted two and one-half times as long as the malleable-iron buckets. We use manganese-steel screen plates on our 2-in. trommels and have found that they last about five times as long as cast iron. We also used manganese-steel wheels and rails under the 20-deck round table in our slimes-treatment plant. We first used cast-iron rails and wheels and found that these wore badly at the end of two or three weeks, while the life of the manganese steel seemed to be almost indefinite; we never had occasion to change any of the manganese steel rail sections or wheels in the year and nine months that the plant was in operation.

Jan 5, 1916

By Kenneth M. Bravinder, Jonathan E. Koogle, Dean H. Sheldon

The solution of subsurface geological problems requires an analysis of vertical and horizontal dimensional relationships. For many, the ability to visualize structures in three dimensions is not easily acquired, and for areas where the structural conditions are complicated by faulting the need arises for illustrative models. This has led to the many forms of peg models, in which the usual course of construction includes a peg for the well bore, and the suspension of strings from peg to peg to illustrate the formation correlation between wells, thus developing the usual folds and flexures. Such models proved unsatisfactory for the analysis of fault problems. Consideration was then given to the use of transparent materials. A model of the Dominguez oil field was constructed in 1935, which consisted of a series of glass panels irom well to well on which the formations were shown in color. This model, though serving its purpose at the time, proved to be impractical from the standpoints of cost, breakage hazard, and extreme difficulty in maintenance. The cost of materials was estimated to be approxi-mately $300, and the construction required the services of one man for a period of from 10 to 12 months. Maintenance after actual construction was an additional expense. Consideration was then given to the use of celluloid, and aiter some experimental work it was found that the advantages in its use were: (I) a short construction time, (2) ease of handling the material, (3) sec-tions are easily reworked, (4) low cost. Construction It would be of little value to recount here the difficulties encountered in the building of the first celluloid model. The conclusions drawn, however, suggest the following pro-cedure for those who contemplate the construction of such a model: 1. Determilzatiolz of the Scale.—Accurate geological interpretation requires the use of the same scale horizontally and vertically. It should be emphasized that the limited size of the celluloid sheets (20 by 48 in. maximum dimensions), the area to be studied, the maximum depths to be plotted, and area of possible future development are the controlling factors in adopting a scale to he used. 2. Construction of the Base.—A satisfac-tory base may be constructed by using two pieces of three-ply wood separated by strips of I by 2-in. material. This type of construction prevents warping of the base. The size of the base is determined by the dimensions of the area to be studied plus 5 in. on all sides. A map of the same scale as that adopted for the model, indicating the lines of section to be used, should be fastened to the base. 3. Constructiolt of the Frame (Fig. I).—In the construction of the frame the use of %-in. 0.d. pipe welded in a box shape is suggested, with two horizontal rods on each of the four sides, top and bottom. The top rod should be at least r in. higher than the

Jan 1, 1941

By Kenneth M. Bravinder, Jonathan E. Koogle, Dean H. Sheldon

The solution of subsurface geological problems requires an analysis of vertical and horizontal dimensional relationships. For many, the ability to visualize structures in three dimensions is not easily acquired, and for areas where the structural conditions are complicated by faulting the need arises for illustrative models. This has led to the many forms of peg models, in which the usual course of construction includes a peg for the well bore, and the suspension of strings from peg to peg to illustrate the formation correlation between wells, thus developing the usual folds and flexures. Such models proved unsatisfactory for the analysis of fault problems. Consideration was then given to the use of transparent materials. A model of the Dominguez oil field was constructed in 1935, which consisted of a series of glass panels irom well to well on which the formations were shown in color. This model, though serving its purpose at the time, proved to be impractical from the standpoints of cost, breakage hazard, and extreme difficulty in maintenance. The cost of materials was estimated to be approxi-mately $300, and the construction required the services of one man for a period of from 10 to 12 months. Maintenance after actual construction was an additional expense. Consideration was then given to the use of celluloid, and aiter some experimental work it was found that the advantages in its use were: (I) a short construction time, (2) ease of handling the material, (3) sec-tions are easily reworked, (4) low cost. Construction It would be of little value to recount here the difficulties encountered in the building of the first celluloid model. The conclusions drawn, however, suggest the following pro-cedure for those who contemplate the construction of such a model: 1. Determilzatiolz of the Scale.—Accurate geological interpretation requires the use of the same scale horizontally and vertically. It should be emphasized that the limited size of the celluloid sheets (20 by 48 in. maximum dimensions), the area to be studied, the maximum depths to be plotted, and area of possible future development are the controlling factors in adopting a scale to he used. 2. Construction of the Base.—A satisfac-tory base may be constructed by using two pieces of three-ply wood separated by strips of I by 2-in. material. This type of construction prevents warping of the base. The size of the base is determined by the dimensions of the area to be studied plus 5 in. on all sides. A map of the same scale as that adopted for the model, indicating the lines of section to be used, should be fastened to the base. 3. Constructiolt of the Frame (Fig. I).—In the construction of the frame the use of %-in. 0.d. pipe welded in a box shape is suggested, with two horizontal rods on each of the four sides, top and bottom. The top rod should be at least r in. higher than the

Jan 1, 1941

By William R. Webster

An investigation has been made of 500 samples of universal and sheared plates of basic Bessemer and basic open-hearth steel manufactured by the Pottstown Iron Company, the carbon-limits being 0.07 to 0.18 per cent. Through the courtesy of Mr. W. H. Morris, President, I am able to lag before the Institute the results of these tests. The samples tested were all taken from the finished material, and the chemical determinations were made on drillings from the broken test-pieces, which were sent to the chemist without giving him the heat-numbers. The results are such as to encourage me to keep on with the work, and, if possible, to have it carried out on other steels. It is kith this view that I now offer my tables in their incomplete form. My first table mas constructed by grouping the tests according to chemical analysis in various. ways, and making a rough tabulated statement, from which the ultimate strengths were worked out and carefully compared with the actual results of the tension-tests. From data thus obtained, one table after another was worked out, and by this method of "cutting and trying" I finally arrived at the results which I now present in Table I. (p. 771). I do not claim absolute accuracy, but my approximations have proved to be so close that the figures are practical data for current use at the works. The indications are that a pure iron, without carbon, phosphorus, manganese, or silicon, if it could be obtained, would give 38,000 pounds ultimate strength. This is assumed as a base, and to it is added the effect of each of the above elements, as explained below. The upper part of Table I. gives the ultimate strength due to carbon and phosphorus, and is the same for both basic Bessemer and basic open-hearth steels. The lower part gives the increase in ultimate strength due to manganese. By adding this to the amount obtained from the upper part, we have the ultimate strength of basic Bessemer

Jan 1, 1893

By T. G. Chapman

THE writer has carried on experimental work for several years with respect to the simultaneous dissolution of gold by cyanide and the adsorption of the dissolved gold on activated charcoal in ore pulps, fol-lowed by the recovery of the charcoal by flotation. The results of this experimental work have been sufficiently encour-aging to suggest a new process based on the principle of simultaneous dissolution and adsorption of gold, applicable to certain ores and tailings that cannot be treated to advantage by countercurrent decantation or filtration. Applications for patents have been filed and The Dorr Company, Inc. has the exclusive right to license the use of the process. The purpose of this paper is to describe such a process, state its pos-sible advantages and immediate field, and give some results obtained on a laboratory scale.

Jan 1, 1939

By E. Posnjak

IT is rather the general belief that acidified, solutions of ferrous salts are readily oxidized when in contact with air, and often elaborate pre-cautions are taken to prevent it. This, however, is not the case and several statements may be found in the literature expressing surprise at the extreme slowness with which oxidation takes place when air or oxygen is bubbled through such a solution. Thus C. Baskerville and R. Stevenson1 "observed with surprise" that no oxidation apparently took place, as shown by titration with 0.5 N KMnO4, when a stream of air was passed for 3 hr. through an acidified solution of ferrous ammonium sulfate or ferrous sulfate. The same authors state that even the presence of salts such as. cobalt, chromium, copper, manganese, etc., which usually act as oxygen carriers, had "no effect upon the oxidation as was observed by passing air for 3 hr.. through solutions of Mohr's salt acidified with sulfuric acid." While this statement will bee proved further on to be at least partly incorrect the slowness of the oxidation of ferrous salts alone has been previously established by McBain.2 His investigation also showed that the rate of oxidation increases markedly with an increase in the concentration of ferrous sulfate as well as that of oxygen; the concentration of free acid had a comparatively small influence, which in the case of sulfuric acid was to retard slightly the rate of reaction. More recently R. Thomas and E. T. Williams3 investigated the catalytic effect of nitric oxide on the oxidation of ferrous salts, which had been earlier patented by McCulloch.4 They found that the probable mechanism of the catalytic action was the oscillation of the catalyst between two stages of oxidation and its interaction alternately with the oxygen and the ferrous iron.

Jan 12, 1926

By H. R. Thresh, A. F. Crawley

THIS paper reports the results of viscosity measurements on cadmium and indium undertaken as part of a continuing program of liquid metals research at the Mines Branch, Department of Energy, Mines and Resources, Ottawa, Canada. For several years this work has continued with support from the Canadian Zinc and Lead Research Committee and the International Lead and Zinc Research Organization. In the literature, existing viscosity data for cadmium are conflicting and for indium are scarce. To achieve reliable viscosity values, further work was deemed desirable. Viscosities were measured using an absolute technique applied to an oscillating closed right cylinder of liquid metal. The apparatus, constructed in this laboratory, and the techniques involved in its use have been described in an earlier paper.' In calculating viscosity coefficients from the experimental data. Roscoe's2 mathematical analysis was used. Because accurate viscosity determinations are dependent on accurate density data, and since the available data in the literature are conflicting, the densities of liquid cadmium and indium were also determined in this laboratory by a pycnometric technique. This increased the control exercised over all the variables contributing to the accuracy of viscosity measurements. For both density and viscosity determinations, cadmium and indium of 99.999 pct purity were used. These materials were obtained from Cominco Ltd. In order to suppress excessive evaporation losses and help prevent oxidation, a technique developed in measuring the viscosity of zinc' was used for cadmium. This involved maintaining an atmosphere of purified hydrogen in the viscosimeter during the rela- tively long periods while the experimental temperature was changed and stabilized between individual determinations of the logarithmic decrement. Then, immediately prior to a decrement measurement. the viscosimeter was rapidly evacuated to a pressure of about 2 X 10-6 torr. On the other hand. with indium. no difficulties arise from vaporization or oxidation. In this case. therefore. the apparatus was held under a constant vacuum of about 2 x 10-6 torr. When all sources of random and systematic error have been evaluated, the technique is considered to yield data accurate within 10.5 pct. The viscosity of cadmium was measured to a maximum temperature of 451.8°C and that of indium to 346.5°C. These temperatures are. respectively. 130° and 190°C above the melting points. Two separate runs were made on indium. The results are given in Table I and, when plotted. yield the smooth curves evident in Figs. 1 and 2. Values of A and C to fit the well-known Andrade1 equation were determined by a regression analysis. The equation is: where n = coefficient of viscosity. i = specific volume. T = temperature in °K Despite its empirical nature. Andrade's equation has been shown by many workers to describe accurately the temperature dependence of viscosity. During the current research program, this equation has been found to fit the data precisely for all the metals and alloys that have been studied.5,6 The A and C' values for cadmium and indium are given in Table 11. Comparing the magnitude of the present data with those of previous workers,7-10 as has been done in Fig. 1, it is evident that the results of Fisher and Phillips10 deviate markedly from the rest. With the exception of one point from Gering and Sauerwald,7 all other data agree within ±2.5 pct. However, the agreement between the present results and the work of Menz and sauerwald9 is especially good over the entire experimental temperature range. Such agreement may be expected since Menz and Sauerwald's

Jan 1, 1970

By Arthur V. Abbott

In a few places attempts have been made to introdnce some means of delivering heat from a central station. Probably Pittsburgh, through the advantages derived from its almost inexhaustible supply of natural gas, has made a more wide-spread success in this direction than any other city. From the gas-wells in the vicinity of that town an enormous supply of natural gas can readily be obtained at a pressure sufficient to force it many miles from its source and to distribute it to all consumers. Obviously, very few places have such natural advantages, and some other means must be devised, if it is desired to furnish heat in a location not supplied with gas-wells. Several plants have been introduced to deliver heat by

Jan 1, 1888

By J. H. Nead, J. W. Halley

The new low-alloy high-strength steels are obviously here to stay. With 75 per cent higher yield strength and 50 per cent higher tensile strength than plain carbon structural steel, they permit 20 to 40 per cent weight savings and 10 per cent or more increase in pay load in the construction of railroad cars, buses, trucks, and a great variety of material-handling equipment. Their cost is low enough so that the extra cost of the new lighter construction over that with carbon steel offers an attractive self-liquidating investment; in some instances new construction with these low-alloy steels may even be as cheap as with plain carbon steel. A considerable and rapidly growing demand for the low-alloy steels has already sprung up. The many steel compositions that have appeared on the market lately18, 27, 28, 29, 30 to meet this demand would seem to indicate that no single composition is uniquely fitted for the purpose. However, no doubt some compositions are more suitable than others. The purpose of this study was, therefore, to compare the effects of the various alloying elements that might be used in the low-alloy steels in order to choose the metallurgically most logical composition, paying due regard, of course, to the economic aspects involved. Properties Desired in Low-alloy Steel A distinction between the new low-alloy steels and the common alloy steels is that the latter are generally used in the heat-treated (that is, quenched and tempered) conditions, whereas the new low-alloy steels are not only not heat-treated but are not susceptible to heat-treatment in the ordinary sense of the term. In this lies one of their chief advantages. Their properties can be obtained in the as-rolled, air-cooled, or annealed condition, just as with mild plain carbon structural steel. There is no need for heat-treating. Such steels can be readily formed hot or cold, and their properties are not appreciably changed by hot

Jan 1, 1936

By J. H. Nead, J. W. Halley

The new low-alloy high-strength steels are obviously here to stay. With 75 per cent higher yield strength and 50 per cent higher tensile strength than plain carbon structural steel, they permit 20 to 40 per cent weight savings and 10 per cent or more increase in pay load in the construction of railroad cars, buses, trucks, and a great variety of material-handling equipment. Their cost is low enough so that the extra cost of the new lighter construction over that with carbon steel offers an attractive self-liquidating investment; in some instances new construction with these low-alloy steels may even be as cheap as with plain carbon steel. A considerable and rapidly growing demand for the low-alloy steels has already sprung up. The many steel compositions that have appeared on the market lately18, 27, 28, 29, 30 to meet this demand would seem to indicate that no single composition is uniquely fitted for the purpose. However, no doubt some compositions are more suitable than others. The purpose of this study was, therefore, to compare the effects of the various alloying elements that might be used in the low-alloy steels in order to choose the metallurgically most logical composition, paying due regard, of course, to the economic aspects involved. Properties Desired in Low-alloy Steel A distinction between the new low-alloy steels and the common alloy steels is that the latter are generally used in the heat-treated (that is, quenched and tempered) conditions, whereas the new low-alloy steels are not only not heat-treated but are not susceptible to heat-treatment in the ordinary sense of the term. In this lies one of their chief advantages. Their properties can be obtained in the as-rolled, air-cooled, or annealed condition, just as with mild plain carbon structural steel. There is no need for heat-treating. Such steels can be readily formed hot or cold, and their properties are not appreciably changed by hot

Jan 1, 1936

By F. R. Morral, K. T. Aust

The preferred orientation and earing characteristics of ZS aluminum were studied. An empirical correlation was obtained relating earing behavior and variation of mechanical properties for face-centered cubic metals. Strain-ratio mecsurements for ZS were found to be in good agreement with Hill's theory of plastic anisotropy. DIRECTIONALITY in sheet metals may be revealed by earing in a cupping test, or by the variation of mechanical properties of tensile specimens taken at different angles to the rolling direction. However, no simple correlation appears to exist between earing and variation in mechanical properties in metals and alloys studied.1-5 Aluminum of commercial purity (known as 2S, with a specified minimum of 99.0 pct Al) cast by the direct casting process was chosen in the present investigation since ears at 45° or 0°, 90° can readily be obtained. Preferred orientation is often the principal cause of uneven metal flow, such as earing, and variation in mechanical properties. Consequently, the preferred orientation characteristics of 2s aluminum were initially studied using both X-ray diffraction and micrographic techniques. The variation of mechanical properties with angle to the rolling direction was next determined in an effort to clarify the apparent lack of correlation of earing behavior with mechanical properties for face-centered cubic metals. Strain-ratio*5,8 measurements were finally conducted to determine first, if the maximum values of the strain ratio occurred at the earing positions, and second, if Hill's theory of plastic anisotropy7 is applicable to other face-centered cubic metals such as aluminum. Detailed treatments, working, and heat treating are not given in this paper since this study is not concerned with the methods to produce earing, but to correlate earing with other properties and characteristics of the material. The percentage of earing was measured using the formula specified by the x—Y Aluminum Association, -------- X 100 = pct earing, where x is the height of the ear and y is the height of the valley from the bottom of the cup. Preferred Orientation Characteristics of 2S X-ray Studies: Beck and coworkers8 have determined that the rolling texture of 2s after 95 pct cold reduction may be approximately described by four equivalent ideal orientations near (123) [121]. Also, the recrystallization or annealing texture of 2s aluminum consists of four components of the (123) [l21] type, retained from the rolling texture, and of a (100) [001] or cube texture component." Fig. 1 illustrates the typical appearance of deep drawn earing cups with the corresponding X-ray diffraction patterns. The X-ray patterns were taken with copper radiation using the structure-integrating method'" in which the specimen is scanned during the X-ray exposure. The rolling direction was vertical and the rolling plane was perpendicular to the horizontal X-ray beam. It was found that an increase in the retained rolling texture component resulted in a greater 45" ear height, while an increase in the recrystallization texture component (i.e., cube texture) caused greater 0°, 90° earing. X-ray diffraction studies of 2s cold rolled to final thickness followed by a final anneal have shown that the rolling texture, and also the retained component of the rolling texture after annealing, are increased with greater cold-rolling reduction. The preferred orientation characteristics of 2s sheets given an intermediate anneal between cold rolling followed by a final anneal were found to depend on the position of the intermediate anneal during cold rolling. For instance, three identical samples of 2s homogenized ingot, each 1 in. thick, were given the following cold-rolling and annealing treatments: 1—50 pct reduction, intermediate anneal, 96 pct reduction to 0.020 in. and a final anneal; 2—75 pct reduction, intermediate anneal, 92 pct reduction to 0.020 in. and a final anneal; and 3—90 pct reduction, intermediate anneal, 80 pct reduction to 0.020 in. and a final anneal. The intermediate and final annealing treatments consisted of a 70°F per hr heating rate, held 6 hr at 800°F and air cooled. Typical X-ray patterns after each of these treatments are shown in Fig. 2. It was evident that after treatment 1, the retained rolling texture component predominated; after treatment 2, the retained roll-

Jan 1, 1954

By L. M. Cathles, L. E. Murr

Results of two years of leaching of 160 metric tons of low grade industrial copper sulfide waste in a large (40` high 10` diameter) thermally insulated tank at the New Mexico Institute of Mining and Technology are analyzed in the light of a previously developed model of the waste leaching process. It is shown that the model is verified in all major aspects and that the parameters in the model that characterize the leaching of a particular sulfide waste are usefully constrained by the results of the tank leaching experiment. The similarity between waste leaching parameters determined from the tank experiment and from interpretation of the leach behavior of test dumps constructed of similar waste encourages optimism it may be possible to predict the leach behavior of field dumps from suitably interpreted column experiments using the computer model developed.

Jan 1, 1980

By J. E. Hackford

IN SOME research. work carried out by the writer, certain results have bean obtained which bear on the fundamental nature and origin of coal and the relationship between coal and petroleum. Without entering into a discussion of the details of the experiments, which were conducted on petroleum and derived bitumens, there are given here, by way of definition, some of the relations that the writer has established between certain classes of bitumens of petroliferous origin. Bitumen.-A natural organic substance, gaseous, liquid, or solid, consisting of hydrocarbons and the oxy- or thionic derivatives of the same, or of a mixture of all three. Diasphaltenes.-Those portions of bitumens that are soluble, in ether or carbon disulfide, but are insoluble in a mixture of equal parts of ether and alcohol. Diasphaltenes are produced by the oxidation or thionization of petroleum oils; they have, as the name indicates, twice the molecular weight of asphaltenes, into which they are converted when subjected to moderate temperature. For example, an artificially produced diasphaltene, which was readily soluble in pentane and ether, was quite insoluble in either of these solvents after heating for three weeks at a temperature of 100° C., and was converted into an insoluble asphaltene. Asphaltenes.-Those portions of bitumen that are insoluble in ether or ether alcohol but are soluble in carbon disulfide. Asphaltites.-Those solid or semisolid natural bitumens that are composed, for the most part, of asphaltenes or diasphaltenes. A pure asphaltite1 would be composed wholly of asphaltenes and diasphaltenes, but most asphaltites contain small percentages of oil and wax, which have not yet been converted into asphaltenes; they may also contain a small percentage of kerotenes, which represent the next stage of the metamorphosis of asphaltenes. Among the naturally., occurring oxyasphaltites may be mentioned grahamite; and among the thioasphaltites, gilsonite.

Jan 8, 1920

By William Newnam

WHEN Hugh Lee Pattinson discovered, in 1829, that the crystals formed during the slow cooling of molten lead were poorer, and the remaining liquid richer in silver, than the original lead, an important step was made in the metallurgy of this metal. Being the first process applicable to the desilverization of low-grade lead bullion, it soon found its way into all European countries having such a product to treat, thereby effecting the saving of many ounces of silver annually which previously had been thrown away. The old hand process was expensive, as viewed from the standpoint of more modern methods; the labor was great anti the tonnage was small, but on the other hand the results were fairly, satisfactory. This process flourished for some time after the introduction of the cheaper Parkes process in 1852 and it is still in use in a few European smelteries. Only one notable improvement was made on the original process, that of Luce and Roan at Marseilles, France. It consisted in the application of steam for stirring and the tapping of one-third of the liquid lead, through perforated plates covering the tap holes flush with the bottom of the kettle, thus leaving two-thirds in the form of crystals in the original kettle. This modification considerably lowered the operating costs as it permitted of much larger kettles, an increased tonnage and eliminated much of the slow, hard labor of the hand process.. The Luce and Rozan process has persisted in its original form to the present clay. Stephen Tredinnick, English born, spent most of his years around the Luce and Rozan plants at Marseilles and elsewhere in Europe, coming later to Eureka, Nev., in 1878, to operate the Luce and Rozan plant at that point. Mr. Tredinnick was a competent Luce and Rozan operator and being devoted to the process he firmly believed that with modifications the costs could be so lowered as eventually to supplant the Parkes process.

Jan 5, 1917

By Paul L. Russell

7.5-1. introduction. The possible engineering uses of nuclear explosives were recognized with the first nuclear detonation. Subsequent experiments have demonstrated the ability of nuclear explosives to move very large volumes of rock and earth efficiently and at costs below conventional earth-moving methods. The ability to package a quantity of energy equivalent to a few million tons of conventional explosive in a container approximately 20 ft long and 36 in. in diameter enables easy emplacement and thus provides the potential for excavation on scales heretofore impossible. Space does not permit detailed discussion of the many experiments with conventional high explosives and with nuclear explosives that were performed in developing the information presented here. A bibliography is included for those wishing detailed information. Material from those sources and from personal experience has been used freely. 7.5-2. Nuclear Explosives. An explosion, in general, results from the very rapid release of a large quantity of energy within a limited space. This is equally true for both conventional and nuclear explosions, although the energy is produced in quite different ways. In the case of a conventional explosive, this energy arises from chemical reactions. In a nuclear explosion, the energy is produced as a result of the formation of different atomic nuclei by the redistribution of the protons and neutrons within the interacting nuclei. Nuclear energy is of a much higher order of magnitude than chemical energy when equal masses are considered, and the release of this energy is a thousand times more rapid than the fastest chemical detonations. Explosions may be produced by fission or fusion reactions. FISSION. When a free (or unattached) neutron enters the nucleus of a fissionable atom, it can cause the nucleus to split into two smaller parts. This fission process is accompanied by the release of a large quantity of energy. The complete fission of 1 lb of uranium can produce as much energy as an explosion of 9,000 tons of TNT.

Jan 1, 1968

By R. Laird Auchmuty

The A. I. M. E. Subcommittee on Bituminous Mining has been trying for several years to secure the information that was collected by the Marquette Cement Manufacturing &. on the subsidence of its property caused by mining coal beneath it. The Marquette company was willing to have these data used, but it was impossible to obtain them because the records had been filed away. About two years ago these records became available and the engineering data presented herewith were compiled from them by R. L. Auchmuty, assisted by L. E. Young, who was connected with the collection of the information. On account of the cost, it is impossible to reproduce all of the data here, although the original information is on file with the records of the Committee on Ground Movement and Subsidence. The accompanying charts show representative and average data and give only the engineering information with enough description to tell how it was obtained. It is hoped that all of those connected with the original case will participate in the discussion that this will bring forth. Howard N. Eavenson, Chairman, Subcommittee on Bituminous Coal Mining. PRobably the most complete records of subsidence due to coal mining in the United States are those compiled by the Marquette Cement Manufacturing Co. at LaSalle, 111. These records, covering a period of more than three years, were compiled and used as evidence during the suit of the Marquette Cement Manufacturing Co. vs. the Oglesby Coal Co. at Oglesby, LaSalle County, Ill., in which the cement company successfully endeavored to stop the coal company from mining under its property. Fig. 1 shows a typical section of the geological formation. The cement company was mining the LaSalle limestone which lies about 125 ft. under the surface. The limestone is 30 to 35 ft. thick and underlain by about 15 ft. of shale. The cement company was mining about 20 ft. of the limestone, and in some places 10 to 12 ft. of the underlying shale, by the room and pillar method. The mining of the limestone always preceded the mining of the shale. The coal company was mining by longwall advance methods the NO. 2 seam of coal 42 in. thick underlying the limestone bed by 435 to 470 ft. The coal mine, a very old one, had largely mined out its original property

Jan 1, 1931

By Albert Sauveur

AT the New York meeting of the Institute, February, 1914, Professor Hopkinson and Sir Robert Hadfield presented an important paper entitled Research with Regard to the Non-Magnetic and Magnetic Conditions of Manganese Steel.1 Any contribution on manganese steel by its discoverer necessarily carries with it much weight and is entitled to serious and close consideration. The momentous discovery of that alloy by Sir Robert Hadfield some 30 years ago was the signal for great activity in the field of alloy steels; and the remarkable results obtained in the last two decades probably constitute the most important modern advance in the metallurgy of steel. The authors of the paper referred to above are unable to reconcile with the allotropic theory the interesting results obtained by them in heat treating manganese steel. When they speak of the allotropic theory, however, I understand that they have more especially in mind the existence of beta iron. It is not my understanding that they question the occurrence of iron in the two allotropic varieties known as gamma and alpha. If I am wrong, I trust they will correct me. A careful consideration of the experimental results reported and discussed by the authors leads me to believe that on the contrary they can be very satisfactorily explained in terms of allotropy and that, in the light of our present knowledge, they cannot be accounted for in any other way. The physical properties of non-magnetic manganese steel described by the authors are those pertaining to iron-carbon alloys in which iron is present in the gamma condition, or, in other words, to austenite. The metal is then characterized by great tenacity and ductility and low elastic limit, while its hardness, mineralogically speaking, is not excessive, but of a special kind termed "tough hardness" by the authors. Even when subjected to the restraining influence of a large amount of manganese and of considerable carbon, however, relatively rapid cooling

Jan 9, 1914

By Eugene Guccione

The domestic iron and steel industry is a vital and major segment of the US economy. Including its employees in coal mining, iron ore mining, limestone quarrying, and related transportation, the industry directly provides jobs for approximately 750,000 people, has a $10 billion annual payroll, and indirectly supports a substantial volume of employment for the entire country. Because of its size and visibility, if nothing else, the US iron and steel industry has always been an easy target of attack and has often been subjected to a great deal of political sound and fury. Today, the industry has different troubles and is fighting for survival: it is faced with spiralling costs, inadequate earnings, labor unrest, foreign competition, government over-regulation, an acute shortage of investment capital, and an all-time high debt burden.

Jan 11, 1975

By Walter Lawson

THE first plans were made in 1930 for the mining by open-pit methods of the low-grade disseminated ore body now known as the Morenci open pit. It was not until 1937, however, that final plans were completed and the decision reached to go ahead with the actual development. Many advances were made in open-pit mining equipment during that period of seven years, therefore the ways and means of attack actually used were very different from those originally contemplated. Diesel-operated bulldozers, big trucks, full-revolving electric shovels and electric churn drills constitute the major equipment finally purchased for this modern stripping operation. Neither the bulldozers nor the big trucks were considered in the early operating plans, for at that time bulldozers had not, been used in mining operations and the trucks as yet were undesigned. The full-revolving shovel and the churn drills were not new developments in open-pit equipment, but both had undergone remarkable manufacturing transition, emerging far more efficient and far more dependable than their predecessors. Even the ordinary drilling steel had been fundamentally changed. It was now threaded so that the dulled cutting bits could be detached and replaced, thus eliminating the costly transportation of long bars to the drill shop for resharpening. The decision to use trucks in the preliminary stripping operations was based on the desirability of this type of transportation to economi-cally prepare the pit for rail haulage, coupled with the success that the contractors had had with them on other big excavation jobs. There are at present no plans for the use of trucks beyond the preliminary work, inasmuch as rail haulage will give lower costs after roadbeds and benches are once established.

Jan 1, 1938