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By George L. Reiter, George B. Clark

Commercial strip mining of coal was first begun in the state of Illinois in 1911.l The annual tonnage of coal produced from coal strip mines in the state was very small until 1924, when the strip mines shipped 1.68 pct of the total state shipping mine tonnage. Since then, strip mines have gradually come into their own by producing a sizable percentage of the coal produced in the state. Table 1 shows the coal tonnage shipped from both underground and strip coal mines in the state of Illinois for selected years. The table illustrates the major role that strip mines play in the state's coal industry. Today, strip mining is generally conducted in areas where the coal seams lie so close to the surface of earth that a stripping method of mining the coal seam is cheaper than an underground method. Strip mining not only recovers 100 pct of the coal deposit, but may also be used as a method of mining large acreages of coal abandoned by the closing of underground mines. Open cut or strip mining is a very highly mechanized method of producing coal and is carried on in three distinct and separate operations. The first of these is uncovering or exposing the coal seam so that the coal is made available for mining. The second operation is that of actually mining the coal. The third operation is the washing, crushing and grading of the coal according to the producer's market. Description of Shovel The Marion 5560 power shovel is used in the first of these three operations. The large electric-powered shovel works forward and back across the coal deposits, removing the overburden of dirt, rock, and clay in successive cuts of 30 to 60 ft deep and 40 to 80 ft wide. The shovel has a maximum cutting height of 95 ft, but around 60 ft is considered to be the maximum economical cutting height by the operators. The smaller the depth of cut, the more economically the shovel will operate until a minimum cut of 15 ft is reached, below which the efficiency decreases rapidly. The Marion shovel may be used in tandem stripping in excessive depths of overburden. The other type of excavating equipment used in the tandem team is generally a dragline with a long boom of about 180 ft. In tandem stripping, the dragline is used to remove the upper portion of the cut and to place it at a maximum dumping radius from the place of removal. The Marion 5560 power shovel is then used to remove the overburden left above the coal seam and to deposit it at the shovel's maximum dumping radius. The Marion 5560 power shovel is of gigantic proportions. It has a 102 ft 6 in. boom and 32 cu yd dipper and is

Jan 1, 1950

By James Douglas

I had the good fortune to visit the Stockholm Exposition just before its close in October last, and to get a glimpse of the methods used in Sweden in making the wonderful steel and iron for which its furnaces are so famous. My time and opportunities for observation were limited, but some points which I noted may be worth bringing to the notice of the Institute. The Exposition itself was confined to the natural and artificial products of Scanclinavia, and therefore iron and steel held a very prominent place in it. There was a complete collection of the rocks and ores of the Peninsula made by the Geological Survey; and every iron-mine of note exhibited a glass model of its workings, as well as classified specimens, accompaniecl by thorough analyses of the ores. Another feature of interest was the display of models of the old mining-machinery, in the invention and introduction of which Sweden led the way, and of the old and new surveying-instruments and compasses devised for the exploration of the Swedish iron-ore bodies, all of which are more or less magnetic. The magnetometric collection and exhibit of methods of operation made by Prof. Nordestrijm were supremely instructive. The larger metallurgical works, such as those of the Kopparberg and Sandvik companies, exhibited their wares in separate pavilions, in which crude and manufactured objects were arranged most eflectively and tastefully; while the smaller companies erected in the Industrial Arts Building trophies, every one of which was an object of beauty. One was struck on all sides by the fine asthetic feeling exhibited in the ingenious installation of materials and objects not easily lending themselves to artistic treatment. Hammers, picks and drill-steel were grouped into mural designs which it was a delight to look at.

Jan 1, 1899

By E. E. Brownson

This paper will be confined to the treatment of methods as applied in the laboratory of the Boston and Montana Reduction Department of the Anaconda Copper Mining Co. at Great Falls, Mont. As the electrolytic plant of this company operates at a current density of approximately 35 to 40 amperes per square foot when running up to capacity, the arsenic and antimony content of the anodes delivered to the plant is of considerable importance as bearing on the purity of the refined cathodes turned out. Owing to the rather high relative percentage of antimony, it has always been the custom to determine antimony as well as arsenic in all forms of copper. Thus, anodes have been analyzed in which the antimony was about equal to the arsenic, although the average shows about 2 parts of arsenic to 1 of antimony. In the refined copper the relative proportions of the two impurities vary considerably, but probably in the average are about equal. In this latter case, the percentage of the two is SO small that ordinarily no attempt is made to separate them, the report of analysis showing percentage of As and Sb combined. Although rapid and exceedingly accurate determinations of arsenic may be made by means of various distillation schemes, the determination of antimony, either by itself or together with arsenic, has always been more or less cumbersome and has required a considerable amount of time. By the methods, details of which follow, the determination of arseluic and antimony, either separated as in the case of anodes or together in case of refined copper, is accomplished in 24 hr. from the time the sample is received by the chemist. As to the accuracy of the results obtained, it can be quite positively stated that in this respect these methods are very satisfactory, much more so than any heretofore employed in our work, and when the rapidity of determination is considered, the results are very accurate.

Jan 1, 1914

By B. Silliman

The experiments detailed by Dr. Hunt,* having demonstrated the fact that the copper contained in the "clay ore" of Jones's Mine, was rendered completely soluble in the bath of ferrous chloride, used in the Hunt and Douglas process, after heating in contact with carbonaceous matter in a close vessel, I set myself to devise a form of muffle furnace adapted to the treatment of large quantities of these and similar ores by a continuous process. The result is shown in the diagrams on Plate X, reduced from the working drawings, after which this furnace was built early in 1876, at Phœnixville, by the Chemical Copper Company on their works at this place. The peculiar character of this ore determined the form, dimensions, and position, with reference to charging and discharging of these muffles. The ore arrived from the mine with from 20 to 25 per cent. of moisture, and when dried at 21o F., or more slowly at lower temperature, it falls to a light incoherent powder, with occasional lumps of undecomposed rock. In this condition it is readily mingled with coal-dust or any like reducing agent, and requires no other preparation for the muffle than the use of the shovel, to mix it well with the reducing agent. As it is a remarkably good non-conductor of heat, it was obvious that the mass, to be heated through in a reasonable time, must not be too thick, while the weight of the mass must be sustained in a way to avoid undue strain upon the walls of the muffle. These walls must be as thin as practicable, to favor the more rapid transmission of heat, and must, therefore, be so constructed as to admit of being stayed on the sides at frequent intervals to resist the lateral thrust of the very mobile mass of pulverulent ore, which, for obvious reasons, must be charged at the top and drawn from the bottom of each chamber. These considerations led to the form adopted, viz., two vertical muffles, standing upon very strong bridge tiles, seen in longitudinal section, on the line E, F, and in plan in Fig. 3, on the same plane. (Plate X.) The vertical section of the muffle is seen in Fig. 4, drawn in the plane G, H, of the longitudinal section, Fig. 6, which is the key to all sections. The walls of the muffles are built of the best firebrick, very care-

By D. C. Porterfield

ProUuction of crude oil in Venezuela increased from 186,134,000 bbl. in 1940 to 2~8,131,ooo bbl. in 1941, or 22.6 per cent, to establish a new all-time high for the country. While the average production for the year was 625,000 bbl. per day, production during the month of December 1941 averaged 751,000 bbl. per day, and during the last week of the year, 766,000 bbl. per day. Production from the Lake Maracaibo basin averaged 454,000 bbl. per day during the year, or 72 per cent of the total for the country, compared with 73 per cent of the total produced in 1940. Drilling during the year was approximately on the same scale as in 1940, with 438 wells completed in 1941 as compared with 429 the year before. Exploratory completions decreased from 18 in 1940 to 6 in 1941. Of the drilling operations in 1941, 56 per cent was concentrated in the Lake Maracaibo basin and 44 per cent in eastern Venezuela, success being 98 per cent in the Lake basin and 83 per cent in the east. Successful completions for the country as a whole amounted to 92 per cent of the total wells drilled. Exploratory drilling in 1941 resulted in the discovery of three new fields, all in eastern Venezuela; viz., Guara, about II km. to the northeast of the Oficina field but on a separate structure; Santa Rosa, which is east of El Roble field on a structure forming a part of the major Santa -Ana- San Joaquin-El Roble uplift; and Santa Barbara, which is southwest of the Jusepin field on an extension of the main Jusepin anticline. At the close of the year three wildcats were drilling, all of which showed prospects of obtaining production; that is, Mercedes No, 2 in central Guarico, Las Ollas No. I on the Anzoategui-Guarico border near the town of Zaraza, and Quiamare No. I in Anzoategui northeast of the town of San Mateo. In spite of heavy withdrawals and the resultant natural decline in the potentials of older producing areas, new drilling during the year increased the potential production of the country from an estimated 780,000 bbl. per day at the end of 1940 to an estimated 810,000 bbl. per day at the end of 1941, or approximately 4 per cent. Since domestic consumption of petroleum products is insignificant compared with total production, exports of crude and products during the year increased in line with production. Crude exports totaled 196,800,000 bbl., compared with 158,400,-000 bbl. in 1940, and exports of products were 26,100,000 bbl., compared with 21,900,000 bbl. the year before. Exports of crude from Venezuela to the United States amounted to 36,500,000 bbl. In addition, about 2,200,000 bbl. was imported in bond into the United States for transfer to Canada. Total refining capacity of the country in 1941 was approximately 125,000 bbl. per day, including a crude-conversion plant with a capacity of 32,000 bbl. per day, capable of making fuel oil only. Three plants with a capacity of 121,000 bbl. Per

Jan 1, 1945

By David S. Butts

The high cost of energy has made many solution mining corporations turn from fuel consuming evaporators to solar energy and solar ponds. The generally held concept of a solar pond is an area enclosed by dikes into which brine is pumped, water evaporated by the sun, and the resulting salts scraped from the bottom of the pond. This paper will show that solar ponding is not simple. It is a science involving six main areas. These areas are (1) land conditions, (2) meteorology, (3) fresh water, (4) accessibility, (5) manpower and (6) mineral resources. Each area is discussed to identify important parameters that must be investigated before the viability of a solar pond complex can be established as a mineral recovery step.

Jan 1, 1985

By Albert J. Phillips

FOR the most part, recent changes in nonferrous physical metallurgy have been gradual and of a transition nature rather than abrupt modifications of existing methods. Development of new alloys containing vital constituents in what formerly would have been considered minute amounts has necessitated more precise control of metallurgical procedure than ever before. Realization of the remarkable effects of minute amounts of specific foreign elements in many alloys has brought about a revolutionary control in the selection of even the most commonplace raw materials. In addition, recognition of the widespread occurrence of precipitation hardness in metal systems, and the utilization of many of these, has emphasized not only the need for precise temperature control but also the necessity for considering the time factor in its effect upon properties in the treatment of most metals. These needs have caused the development and widespread installation of equipment that permits precision of control undreamed of a generation ago.

Jan 1, 1935

By A. Simkovich, R. W. Lindsay

The possibility of using sodium sulfide slags to remove copper from ferrous alloys has been investigated by Jordan1 and by Langenberg.2, 3 In these studies, such slags were determined to be capable of removing copper and sulfur from the melt. The present work represents additional effort to clarify the effects of temperature on copper removal. The experiments were performed in a 17-lb induction furnace. Graphite crucibles contained the melts and kept the baths saturated with carbon. Temperatures were measured with a calibrated optical pyrometer and were controlled by manipulation of power input to the furnace. Estimated accuracy of temperatures in this investigation is ± 10°C (18°F) for measurements prior to slag additions, and + 20°C (36°F) after slag formation. The procedure consisted of melting 800 g of electrolytic iron. During this step, powdered graphite covered the exposed iron surface. After a predetermined temperature was reached, copper shot was added. A sample of the molten alloy for chemical analysis was then aspirated into a silica sheath. Next, a slag-forming mixture of sodium sulfite and graphite was added instantaneously to the melt. The sodium sulfite amounted to one-tenth the charge weight of iron; sufficient graphite was added to combine with oxygen in the sodium sulfite, assuming formation of carbon monoxide and reduction of the sulfite to sulfide. Subsequent to the slag addition, the molten alloy was sampled periodically, with the exception of heat A in which no intervening samples were taken between the slag addition and the end of the run. The iron was poured into a graphite mold, and the ingots sectioned and drilled for samples. Results of selected heats are presented in Table I. Analyses of samples drawn from the iron prior to slag addition are listed under zero time. Two samples from heat D were reported with copper contents greater than the initial concentration in the bath. Owing to the gradual but complete disappearance of slag during this heat, it is believed copper momentarily became more concentrated in the upper portion of the bath while reverting from the slag. This is the region from which samples were drawn. It should be noted that analysis of the ingot was equal to the copper content at the time of slag addition. The terminal temperatures of heats D and E, and the initial sulfur content of heat A are also to be noted. Because of the large temperature drop which occurred when slag was formed in heat D, power input to the furnace was increased in heat E after the slag addition, causing a higher terminal temperature. In heat A, the initial sulfur concentration was relatively high as compared to heats B through E owing to contamination by some slag remaining in the crucible from a previous heat. It is evident from Table I that copper was removed at the onset of slag formation. Roughly 30 pct of the copper was taken into the slag, with the exception of heat D, which had approximately 50 pct removed. For a comparatively short time of slag-metal contact, it appears that no gain is to be made in copper removal through use of high or low temperatures. If the slag initially formed remains in contact with the iron for an extended period, temperature has a marked effect upon copper removal, as can be seen by studying results for the two extremes in temperature. At about 1425°C, the copper level remained relatively constant after the initial removal by the slag. However, in the region of 1670°C, a definite reversion of copper occurred. Reversion was incomplete in heat D, and complete in heat E. The final temperatures of heats D and E differed by about 75°C. This temperature difference is thought to be the reason for only partial copper reversion in heat D. It is believed the effects of temperature noted above are related to the evolution of a white fume, which appeared in every run except heat A. (In the case of heat A, the fume was practically indiscernible.) After each slag addition, a yellow flame formed for about 5 sec. When the flame subsided, a white fume appeared. Upon contact with surrounding cooler surfaces, this fume deposited as a white solid. In the experiments made at 1425°C, evolution of fume continued unchanged to the end of the runs. However, heats D and E exhibited a different behavior. A very noticeable decrease in fume evolution from heat D was observed. Furthermore, this heat had much less slag remaining than did runs A through C when the experiments were terminated. No slag remained at the end of heat E; evolution of fume from this heat ceased prior to pouring. Spec-trographic analysis of the white deposit indicated sodium to be the major metallic element, with the maximum concentration of iron and copper as 0.1 and 0.01 pct, respectively. It is supposed the white fume observed in these experiments is principally sodium oxide (Na2O), formed by oxidation of sodium in the slag and subsequent sublimation. (Sodium oxide is a white to gray substance in the solid state; at 1275oC, it sublimes.4) According to this mechanism, elevated temperatures would accelerate removal of sodium from the slag, sulfur pickup by the

Jan 1, 1961

By M. R. Tek

A new method for correlating the data on multiphase flow through vertical pipe is presented. The correlation is based on a "two-phase f factor" concept which was developed and successfully applied to horizontal multiphase flow by Bertuzzi, Tek and Poettmann. Field data previously published on several flowing and gas-lift wells have been used as the basis for the developed correlation. The application of the method to actual two-phase flow problems indicate that this method is capable of predicting the pressure distribution in vertical multiphase flow strings well within the accuracy range usually desired for common engineering and design calculations. A new working chart developed for calculation of two-phase pressure gradients and a graphical step-by-step procedure for the computation of pressure distribution are presented along with an example problem. INTRODUCTION Multiphase flow through vertical pipe is encountered in many engineering installations. In petroleum, chemical process, nuclear engineering and many other industries, problems associated with simultaneous flow of two or more phases through vertical pipe have been of interest for a long time. This interest has increased considerably during recent years due to applications to new processes in petroleum production and refining and to problems of steam generation and heat removal from nuclear reactors. One prominent example of vertical two-phase flow is provided by the gas-lift process where oil, water and gas flow simultaneously. If the pressure profile in a gas-lift well can be predicted within reasonable accuracy, it would be possible to get good estimates of the power required to lift the oil, the optimum depth, the pressure and the rate at which to inject gas. Furthermore, the effect of production rate and tubing sizes on these quantities can be evaluated before any design decision is made on the installation and operation of the flow string. The majority of experimental work available in the literature deals with two-component systems where individual phase flow rates in and out of the pipe remain constant. The general problem of prediction of pressure drops in multiphase flow systems is very complicated. The co-existence of numerous flow patterns of widely different geometry and mechanism, conditions of surface instability and the nature of force fields acting upon the system are among the major difficulties commonly encountered. The classical approach of fluid dynamics which would be based upon the formulation and solution of Navier-Stokes equations has been found by many investigators completely devoid of any hope of success-—not only because of inherent nonlinearities but also because of insurmountable analytical difficulties standirng in the way of setting up the boundary conditions. The presence and effect of interfacial forces on mu1tiphase flow systems further complicate the theoretical approach. For these reasons, many investigators choose to adopt semi-empirical if not purely empirical approaches in order to obtain solutions of engineering utility. A prominent practical solution has been given by Poettmann and Carpenter' in the form of an empirical correlation. In their paper, total flowing densities of fluids and solubility effects of gas in oil have been taken into account for the correlation of field data covering a wide range of operating conditions for oil wells. They treated the gas. oil and water as a single phase of combined propcrties and correlated the multiphase friction factor as a function of the product (pvd), i.e., density X velocity X diameter of the flow string. However, because the product (pvd) is dimensional while the frictior factor is dimensionless, the generality of their result's is somewhat restricted. It seems that the omission 01 viscosity effect may be one of the reasons for the scatter of data as shown in their correlation chart. The concepts of the "two-phase f factor" and the "two-phase Reynolds' number function" were recently developed and successfully applied to correlate horizontal multphase flow by Bertuzzi, Tek and Poettmann.' Recently, two new methods of correlation by Tek and Chan' have been presented on simultaneous flow of liquid and gas through vertical pipe. These two methods of correlation and the working equations in field units necessary for their application are included in this paper. The extension of the conccpt of two-phasc Reynolds' number function successfully developed for horizontal flow into vertical multiphase flow systems, development and evaluation of working charts permitting calculation of two-phase pressure gradients and

By Kennedy, Joseph E.

MANY things must be considered in coming to a decision as to what type of crushing and grinding equipment is to be used for preparing run-of-mine ore for concentration, amalgamation, flotation, or cyanidation. This paper is intended in no sense as a thorough discussion of these various factors, but rather contains a few observations based on a wide experience in the manufacture and application of milling machinery. One important governing factor is the tonnage to be dealt with. In large plants treating several thousands of tons in eight hours, a large jaw or gyratory crusher of substantial construction is standard equipment for reducing ore to 8 or 10 in. or finer. In open-pit work, using power shovels with 4- or 5-yd. dippers, a jaw crusher should have a receiving opening of 48 by 60 in., or 60 by 84 in., so that dynamite or hand sledging will not be required for breaking to a finer size before primary crushing. The coarsely broken ore is then conveyed by a belt to vibrating screens, the oversize from which is again conveyed by belts to secondary crushers having openings of 12 or 14 in., the product from which is conveyed to storage. From storage, the material goes to a finishing gyratory for reduction to 1/4 in. or finer.

Jan 1, 1936

By Ralph E. Wood

X-ray fluorescence analysis can be profitably applied in the mineral industry by improving evaluation and control analyses, while offering lower cost and greater speed than conventional methods. Chemical analyses are not only a major item of cost in exploration and mining, as well as in milling and chemical treatment, but often cause evaluation and control of processing steps to lag behind operations. In the fields of geology and mining, the X-ray technique can be employed without destroying samples and, if necessary, specimens can be analyzed and then used, unchanged, in other evaluation techniques. Results are quickly made available for decisions on progress of exploration or sorting of waste and ore.

Jan 6, 1959

By O. I. Deschon, Ralph Arnold

Deep drilling was the keynote of the more important developments in the North Rocky Mountain region during 1929, with Montana recording the most important achievement through discovery of three new oil fields. Alberta produced 1,000,000 bbl. of 74 gravity naphtha, showing a considerable gain over 1928, developed a commercial oil pool in Turner Valley and extended that field 8 miles southward. Wyoming's discovery field was deepened to a second producing horizon, giving impetus to deeper drilling, and practically every Wyoming oil field will have a deep test either this year or in the near future. Whereas Montana prospecting has been confined to the shallow plains structures, since the discovery of Kevin-Sunburst field, the coming year will see an active search for new oil and gas pools in sharp-dip structures, following the success of prospecting in the Sweetgrass Hills during 1929. A dozen or more structures have been mapped in North Central Montana, several of these straddling the Alberta border. Four structures tested thus far have all shown commercial oil or gas or both. Sweetgrass Hills The first important development in the Hills area was the Rogers-Imperial gasser, which had an initial of 51,000,000 cu. ft. of dry gas per day, with a rock pressure of 1080 lb. This well is located on a sharp nose running north from the hills into Alberta. Several wells drilled by independent operators on the American side, on the west flank of reserve structure, have developed a total open flow capacity of 30,000,000 cubic feet. The third structure tested in the Hills area is known as Bears Den, where commercial oil was found at the base of the Cretaceous at 2470 ft. The existence of oil in three lower sands has been established by two wells on the top of the structure, these two wells finding gas flows of 10,000,000 and 15,000,000 cu. ft., respectively, in the horizon where

Jan 1, 1930

By L. C. Chang, T. A. Read

Diffusionless transformation in Au-Cd single crystals containing about 50 atomic pet Cd was investigated by means of X-ray analysis of the orientation relationships, electrical resistivity measurements, and motion picture studies of the movement of boundaries between the new and old phases during transformation. The nucleation of diffusionless transformation by imperfections and the generation of imperfections by diffusionless transformation were discussed. THAT connections exist between plastic deformation and diffusionless phase changes has long been recognized. Thus it is often possible to produce a diffusionless phase change in a temperature range, above that in which the change occurs spontaneously, by cold-working the initial phase. Certain aspects of the dislocation theory of the plastic deformation of crystalline solids also provide for a rather direct connection between the processes involved in plastic deformation and in diffusionless phase changes. Heidenreich and Shockleyl have pointed out that simple edge dislocations in f.c.c. metals are probably unstable, and that the more probable lattice imperfections, called extended edge dislocations, consist of two half dislocations separated by a distance of the order of magnitude of 100A. The region about two atomic planes thick between the half dislocations because of this stacking fault may be described as having the hexagonal close-packed structure. Presumably the stacking faults observed by Barrett" fter cold-working f.c.c. Cu-Si alloys resulted from the passage of such half dislocations through the lattice of the initial phase. It is now becoming clear that the development of a detailed theory of the atomic movements involved in diffusionless phase changes will require a consideration of the role played by lattice imperfections, just as such considerations are necessary to the understanding of plastic deformation mechanisms. This point of view has been recently set forth, for example, by Cohen, Machlin, and Paranjpe3 who pointed out the role which might be played by screw dislocations in nucleating diffusionless phase changes. The present paper reports on some aspects of the diffusionless phase change in single crystals of the beta phase alloy Au-Cd which serve to emphasize further the importance of lattice imperfections in diffusionless phase changes. The diffusionless phase change of Au-Cd possesses several remarkable features. One of these is that the interface between the high-temperature beta phase and the low-temperature orthorhombic phase typically moves with a low velocity, in contrast to the behavior observed in the transformation of austenite to martensite. Motion pictures of this slow interface motion have been prepared in the course of the work reported here. Another important feature of the Au-Cd transformation is the small amount of undercooling observed. The reverse transformation occurs on reheating to a temperature only 20" higher than the transformation temperature observed on cooling, and under some circumstances the hysteresis observed is substantially less than this. This narrow temperature range between transformation on heating and cooling is presumably in part a consequence of the fact that the transformation requires a lattice shear of only about 3". Finally, the orthorhombic product phase possesses unusual mechanical properties, as was first pointed out by olander' and Benedicks." After completion of the transformation on cooling the specimen can be severely deformed, yet on the release of load it springs back to its original shape in a rubber-like manner. Explanation of this phenomenon will require an understanding of the lattice imperfections in the orthorhombic structure and, correspondingly, of those in the initial body-centered cubic structure. Single crystals of Au-Cd alloy containing 47.5 and 49.0 atomic pct Cd were prepared from fine gold (99.95 pct purity) and chemically pure cadmium (99.99 pct purity) by melting the alloy in an evacuated and sealed fused quartz tubing and growing into single-crystal form by the Bridgman method. The Au-Cd alloy containing 47.5 atomic pct Cd undergoes a diffusionless transformation from an ordered body-centered cubic structure to an orthorhombic structure when it is cooled to about 60°C, while the reverse transformation takes place when the alloy is heated to about 80°C, according to electrical resistivity studies. The structures of these two phases have been studied by Blander,4 reinvestigated by Bystrom and Almin.e he lines of Debye photo-gram of powdered samples of Au-Cd alloy containing 47.5 atomic pct Cd prepared in this laboratory were identified and agreed fairly well with those of

Jan 1, 1952

By John W. Cabot

THE following series of analyses, which may, be of interest to Bessemer-steel makers, is submitted as a contribution to the much-vexed discussion of manganese in Bessemer steel. They were made by the writer in the spring of 1881, at the works of the Pittsburgh Bessemer Steel Company Limited, during a period of about eight days, part of, which time the rail-steel showed great variation in rolling qualities. During the first part of the time in question, it rolled well; later on it began to roll worse until, finally, it cracked very badly, reaching its worst stage. After this it rapidly improved until it again rolled smoothly. During this .time of transition 'from. good rolling to bad, and back to good again, the course of the manganese was followed' quite closely. It is the striking correspondence between these varying manganese contents and the differences in rolling which is here presented as worthy of notice. The other ordinary elements were determined occasionally, but showed no unusual variation Tim steel, in question, was ordinary rail-steel of about "the following composition : C=.35.P=.08.Mn=.98. Si=.08. S=.05. The samples for manganese determinations were taken at first from an average of two days' work, and later on, when the steel

Jan 1, 1882

By H. C. George

IN 1901, the United States produced 69 million barrels of crude oil, which was 41.4 per cent of the world production. By 1931, these figures were 850 million barrels and 62.1 per cent respectively, showing over this period of thirty years an increase in the world production of 718 per cent. Over this same period, the increase in the demand for technically trained men in the industry was much greater than the increase in crude-oil production. This was because much of the increase in production was secured by the application of geology and physics to the finding of new oil fields and by .the development of engineering methods and equipment incident to drilling and producing from much greater .depths.

Jan 1, 1934

By J. M. Kane

IN all probability the mining and metallurgical industry as a whole can demonstrate a larger economic return from installation of dust-control equipment than any other major industrial group. This fact has partially accounted for the marked increase of dust-control installations made during the past decade. While the primary objectives for installation of dust-collecting systems are improved working and operating conditions for men and equipment, the fact that an economic return can be anticipated on salvageable materials is an added advantage which shows in partial or complete equipment write-off. The conditions apply to most phases of the mining, milling, and smelting industry, both non-metallic and metallic.

Jan 1, 1953

By C. D. Rubert, W. J. Parton

LARGE quantities of fine anthracite with associated impurities are discharged with the waste water from the coal-cleaning plants in the Pennsylvania anthracite region. Furthermore, for many years this fine material has accumulated and formed silt banks. The difficulty of removing the impurities from the fine material and the lack of adequate markets are responsible for the waste of this material. In view of a larger demand for fine coal, mainly for pulverized fuel, the Lehigh Navigation Coal Co. Inc. decided to investigate the froth flotation process for recovery of fine coal from these waste solids. A test plant was constructed and operated for six months during 1942 in order to determine the practicability of recovering coal from the waste water of a cleaning plant (breaker) by froth flotation, and to obtain operating data for designing a commercial plant if the results were favorable. PRELIMINARY INVESTIGATION Before the pilot plant was constructed information was obtained by field and small-scale laboratory tests to serve as a guide in the design and operation of the pilot plant. Size and ash analyses of a representative sample of the material discharged in the wash water from a cleaning plant are given in Table I. [ ] The refuse content increases progressively as the size of the particles decreases. The larger particles (+35 m.) are low in ash content and could be marketed without cleaning. Since these solids are discharged from the breakers with 90 to 95 per cent water by weight, the first step in the recovery of the coal was that of reducing the quantity of water so that water in excess will not have to be handled. Furthermore, it was found that the removal of most of the minus 200 mesh high-ash material was desirable to permit the most efficient flotation of the coal. Classification tests were run and showed that a hydroseparator overflow rate of 12 ft. per hour was sufficient to eliminate much of the minus 200-mesh material while allowing the coarser material to settle and be thickened.

Jan 1, 1944

By A. W. Brune

Conventional methods of calculating the duty cycle of a mine hoist are awkward in that a number of items must be remembered or that they must be collected together in order to have all the calculated data in one place. A more convenient way is to tabulate all factors involved, permitting a ready evaluation of the problem. An example illustrates the convenience of such a table for either of two types of drums, cylindrical and conical. Assume the following conditions: The hoisting depth is 600 ft. Balanced hoisting is used. The weights of empty skip and ore are 6000 lbs and 12,000 lbs, respectively. Production is 3600 tons per shift. Net hoisting time per shift is six hours with a rest period of eight sec, top and bottom, per trip. Acceleration and retardation are each six sec. The diameter of the drum is seven ft; its face is four ft. The sheave has the same diameter. The equivalent effective weight of the drum reduced to rope center is 15,400 lbs. The weight of each sheave is 2100 lbs. 1 The rope is 1 1/4-in. improved plow steel weighing 2.50 lb per ft.

Jan 9, 1961

By GLENVILTE A. COLLINS

(Presented at a Meeting of the Spokane Local Section of the Institute, Feb. 17, 1912, and accepted for publication in the Bulletin. ) WHILE I am not at the present time engaged in active mine-management, my duties permit of extensive study and examination of many mines, mills, and reduction-works in various places throughout the United States. Being much interested in efficiency-work in general, and an ardent reader of writings on this subject by Frederick W. Taylor and others, as applied to manufacturing-plants, and having served my apprenticeship from mucking to the engineering design of ore-dressing and underground plants, I hope that this paper will lead others to investigate the field more fully, to the improvement of general mine- and mill-operations, as well as the advancement, intellectually, physically, and financially, of the employee and his relations with the employer. If a man who is prepared to look closely and observe broadly starts in Canada and zig-zags from camp to camp to southern Mexico, taking time casually to inspect mines, mills, and smelters, he will be pitifully impressed by the great difference in customs, and the general waste of labor, time, and money throughout the country. He will so seldom observe a dollar's worth of results given in exchange for a dollar spent that he will form a poor opinion of operating-efficiency and management. This highly-scientific department, requiring an amount of skill and executive ability equaled in few, if any, of the professions, certainly falls short of the standard established in our greater manufacturing industries. It is easily said that this is due to the diversity of conditions in mining, milling, and smelting. But on second view it must be admitted that there is room for tremendous improvements in nearly every mining-organization. The proposal of such improvements is often met by the argument that any mine

Sep 1, 1912

By C. G. Durdaller, W. H. Robinson, G. M. Pound

The nucleation rate of the a (pay) to 0 (white) tin transformation was measured as a function of temperature and a tin particle size using an X-ray diffraction technique. The powder specimens of a tin were essentially monodisperse and the small dinzension of the particles of these specimens was varied from 13 to 75 p. Several types of nucleation sites of differing potency were fbund to be operative in the nucleation process, but it could not be determined whether these sites were on the free surface of the tin particles or within the volume. Assuming that they were on the free surface, the average density of the most potent sites was calculated to be 2.5 to 5.3 x 10' sites per sq cnz through the application of a Poisson distribztion finction to the isothermal data. Analysis of the temperature dependence' of the rate constmts at a given fraction transformed suggests that the active sites are regions of higher free energy and not catalytic interfaces. Appreciable induction periods were observed at the lower temperatures of transformation. Experimental studies1 of solid-solid phase transformations have led to the belief that the new phase nucleates at structural imperfections. The purpose of the present work was to learn more about the mechanism of nucleation in solids and the nature of the singularities at which nucleation occurs. In this investigation nucleation rates in the isothermal transformation of gray to white tin were measured by an X-ray diffraction technique using essentially monodisperse powders of gray tin. This particular phase transformation was chosen for study because it presented fewer experimental difficulties than most others. The experimental temperature-control problems were minimal because the two phases coexist in equilibrium at 13.3"C, and measurable transformation rates occur at temperatures only slightly above room temperature. The growth rate of the P phase into the a2 is sufficiently fast to make the measured transformation rate equivalent to the nucleation rate, provided that the particle size of the samples is small enough; for the experimental temperatures used in this study, the particle diameter must be less than 100 p. EXPERIMENTAL TECHNIQUE The P tin used in this study was obtained from Capper Pass and Son Ltd., North Ferriby, Yorkshire, England, and was of 99.999 pct purity. It was transformedS to the a phase and ground into a fine powder in an agate mortar. This powder was separated by a Roller air classifier into seven fractions whose dimensions, as determined by microscopic measurement of many thousands of particles, are given in Table I and whose distribution of size within each fraction is given in Figs. 1 and 2. The shape of the particles was roughly that of an oblate spheroid,

Jan 1, 1964