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By Cloyd M. Smith

A few years ago, the Ventilation Committee established the practice of resenting one topic each year for discussion at the annual meeting. The practice has met good response on the part of committee members and I suggest that it be continued. The topic chosen for this year, "Underground Anemometry," is a topic which has bothered me for more than 20 years. It seems to me that the coal industry is content to rely on slipshod methods for measuring the rate of flow of air underground, so I prefaced my discussional charge to committee members with the statement that I regard air measnrements made in the usual way, with hand held anemometer, as no good. Agreements and disagreements came in from more than a dozen engineers, some of whom are with operating companies, coal and metal; some with manufacturers; others with government agencies. The statement was accompanied by a questionnaire on the use of the rotating vane anemometer and by one describing two methods of using a mechanically held anemometer. The questionnaire will be considered first. The questionnaire and statement are as shown on pages 5 and 6, the committee members and respondents are given on page 4, and the general comments of the latter on page 5. Questionnaire 1. Has your company or agency issued written instructions for care and use of anemometers? If so, please enclose a copy with reply. Only one answer, McElroy's, was affirmative. It gave reference to Bureau of Mines publications1'5 which recom- mend the hand held anemometer for rough measurements and indicate that am accuracy of 5 pct can be had if calibration and method factors are used. Mathews said that instructions are principally oral while Maize reported that state inspectors of his department are well trained in use and care of anemometers. 2. Are your anemometers calibrated periodically? If so, by their manufacturer? or by? Are calibralion corrections applied to all observed mean velocity readings? Only one respondent, Lee, answered negatively as to calibration. This means that anemometers are generally calibrated but the questionnaire failed to ask how often this is done. As no one volunteered the information, we have no data on this point. In six cases the instruments are sent to their manufacturers for calibration. but Krickovic reports that his company limits manu-facturers' calibrations to anemometers which are used by operating personnel; those used by the engineering department being calibrated by U. S. Bureau of Standards. The Anaconda Copper Mining Co. has its ventilation engineers calibrate its anemometers. Most of the respondents say that a calibration correction is applied to each mean velocity reading, but Krickovic limits this to surveys made by the engineering department. Since Lee does not calibrate, he has no correction to apply. Maize reports that his department has its anemometers calibrated but does not apply corrections. 3. Do your men hold the anemometer by hand in measuring air flow? for 1 min? or traverse the section? for 1 min? or at? points for 5 sec each? Of 10 replies, 6 were "yes," 3 were "no," and one was "seldom" with respect to holding by hand. Among the six hand holders, four hold in a central position in the measuring section for a minute, except that two of them, Krickovic and Matthews, traverse the section by hand for survey or fan test. Their operating personnel hold by hand, centrally, for routine measurements. McElroy sometimes traverses with hand-held anemometer in rapid survey work. 4. If the anemometer is not held by hand, how is it supported? Augustadt supports the anemometer on an adjustable rod, Condon on "a rod of sufficient length to reach all points with observer standing in one position throughout traverse and at arm's length from plane of traverse." I presume that arm's length must be interpreted liberally enough to allow for arm movement, otherwise it would be impossible to manipulate the anemometer throughout the traverse section. Mancha upholds Condon in this method of traversing. Glanville hangs the anemometer on the end of a 4-ft staff by the hasp at the top of the anemometer frame. McElroy mounts it on the end of a rigid square shaft, 12 in. long, the staff being at right angles to the axis of the instrument. He traverses the section in two halves, holding the anemometer 3 feet from his body.

Jan 1, 1950

Gus C. Henning, New York City: In taking up the discussion of these specifications it is necessary that I give definitions of what I understand under the term " Specifications." There may be three kinds, viz.: (1) Specifications in general; (2) Standard Specifications; (3) Standard International Specifications. 1. A Specification is a document used in commerce which should clearly define the qualities of material to be supplied by the producer, the tests which shall be applied for their determination, and the methods which shall be applied for the purpose of determining that the entire product shall possess such qualities, properties and finish as are desired. The terms used in such document must be applied in accordance with their strict technical definitions as used by those most conversant with them, and the language should be of such accuracy that there can be but a single interpretation of each and every clause. A specification is a part of a contract, and should be legally perfect and accurate. Inaccuracy of definition and dic-

Jan 1, 1903

"In 1899 the American Refining and Smelting Company obtained control of the East Helena Smelter, and have added improvements from time to time.The plant is four miles east of Helena, on the Northern Pacific and Great Northern railroads, with hourly street car service from Helena.Electric power is obtained from Canyon Ferry dam, twelve miles east on the Missouri river, and about 800 h-p. is used in the blowing engines, crushing machinery, cranes and locomotives.Besides the Montana ores convenient to the above railroads, a large part of the ore supply comes from the Coeur d'Alene district, Idaho, and is mainly lead ore and concentrates.A modern automatic sampling mill, with Vezin samplers and a capacity of 50 tons per hour, was completed in 1912.Three blast furnaces, each 48 inches by 136 inches, are now in continuous operation, and the monthly production of silver-lead bullion is six thousand tons.A part of the ore roasting is done in Godfrey furnaces, in connection with the Huntington-Heberlein process, 12 pots being in use, with a capacity of 300 tons per day.Four Dwight-Lloyd sintering furnaces, each 42 inches by 264 inches, and a smaller experimental machine, with a combined capacity of 440 tons per day, are in steady operation, and are successfully roasting ore as well as sintering flue dust. These machines are in great favor and results are being carefully watched.Three bag houses are used in connection with the 1,800 brick flue chamber, and each bag house contains 1,260 cotton bags, each 18 inches in diameter by 30 feet long, suspended on vertical roads. The product saved by the bags contains about 50 per cent lead and is retreated in the blast furnace after sintering.About 450 men are employed."

Jan 1, 1913

By Charles S. Barrett

Recrystallization textures—thc orientations of grains after recrys-tallization—have been studied extensively not only because of their metallurgical importance but also because of the information they yield regarding the atomic movements during reerystallization. Recrystallized grains must possess the same orientations as the submicroscopic nuclei from which they have grown, and thus they offer a direet road by which experimenters can penetrate the submicroscopic realm. Many perplexing results have come of these studies, but one of the most striking has been the apparent difference in behavior between single crystals and polyerystalline grains. For example, Burgers and Louwerse have shown1 that when single crystals of aluminum are deformed by compression and are reerystallized (at 600' C.) the new grains appear with orientations that are different from the orientations of the deformed crystal in which they grew; but polycrystalline specimens, on the other hand, appear to have a [110] fiber texture both before and after reerystallization and thus to retain their texture during recrystallization. This apparent difference between the habits of single crystals and small grains is the subject of the first part of the present research and has been explained by findings reported herein. A similar situation appears to exist for aluminum when elongated or drawn into wires, for single crystals alter their orientation 2,3 and polycrystalline wires retain their texture"5*" upon recrystallization after elongation (at least with high-purity aluminum), and it is possible that the explanation found in this paper for compression can be extended to cover elongatioil and other types of deformation as well. The second part of this paper deals with the theory of reerystallization textures. In the most successful theory for aluminum reerystallized after compression,1 much weight is given to the orientation of highly stressed nuclei in the deformed material. Taylor's "local distortions" arc assumed to exist along the slip planes where displacement has occurred, consisting of fragments rotated in a specific way with reference to the slip plane and slip direction; namely, about an axis lying in the slip plane perpendicular to the slip direction.1,7,89

Jan 1, 1940

By Charles S. Barrett

Recrystallization textures—thc orientations of grains after recrys-tallization—have been studied extensively not only because of their metallurgical importance but also because of the information they yield regarding the atomic movements during reerystallization. Recrystallized grains must possess the same orientations as the submicroscopic nuclei from which they have grown, and thus they offer a direet road by which experimenters can penetrate the submicroscopic realm. Many perplexing results have come of these studies, but one of the most striking has been the apparent difference in behavior between single crystals and polyerystalline grains. For example, Burgers and Louwerse have shown1 that when single crystals of aluminum are deformed by compression and are reerystallized (at 600' C.) the new grains appear with orientations that are different from the orientations of the deformed crystal in which they grew; but polycrystalline specimens, on the other hand, appear to have a [110] fiber texture both before and after reerystallization and thus to retain their texture during recrystallization. This apparent difference between the habits of single crystals and small grains is the subject of the first part of the present research and has been explained by findings reported herein. A similar situation appears to exist for aluminum when elongated or drawn into wires, for single crystals alter their orientation 2,3 and polycrystalline wires retain their texture"5*" upon recrystallization after elongation (at least with high-purity aluminum), and it is possible that the explanation found in this paper for compression can be extended to cover elongatioil and other types of deformation as well. The second part of this paper deals with the theory of reerystallization textures. In the most successful theory for aluminum reerystallized after compression,1 much weight is given to the orientation of highly stressed nuclei in the deformed material. Taylor's "local distortions" arc assumed to exist along the slip planes where displacement has occurred, consisting of fragments rotated in a specific way with reference to the slip plane and slip direction; namely, about an axis lying in the slip plane perpendicular to the slip direction.1,7,89

Jan 1, 1940

By R. W. Parsons, P. R. Chaney

Oil recovery by the imbibition mechanism can be important in fractured carbonate reservoirs with a bottom water drive. Laboratory experiments were performed on water-wet carbonate rocks to model this process. The results are interpreted in light of the applicable scaling laws. The imbibition production behavior of a pillar of rock subjected to a slowly rising water table can be synthesized from data on total immersion experiments on small rock samples. If the rate of water table rise is slow enough and if the physical properties are such that the imbibition zone is of a small vertical extent, then only the final oil recovery on the small samples need be known. Applying laboratory imbibition data to a real reservoir should be done with caution because of possible wettability problems and the unknown behavior of two-phase flow in fractures. INTRODUCTION The spontaneous taking up of a preferential wetting fluid into a porous medium with the simultaneous expulsion of the contained fluid is termed imbibition. One of the many physical imbibition processes is the production of oil by the taking up of water into a water-wet reservoir rock. In certain types of heterogeneous reservoirs, e.g., fractured, it is realized that imbibition alone may be the dominant mechanism. Theoretical studies of imbibition oil recovery have followed several lines of attack. The behavior of certain mathematically tractable and conceptually simple models have been analyzed. Birks1 considered a bundle of vertical capillaries model, while Perotti et al.2 and Kelemen3 used a model of a series of vertically oriented fractures. If the oil production behavior from a block of reservoir rock is known, then the cumulative behavior of a vertical stack of these blocks subjected to a rising water table can be determined by a method outlined by Aronofsky et al. 4 Knowing the capillary pressure and relative permeability functions should uniquely set the imbibition behavior for a given sample. Solutions of the partial differential equations describing the process, however, present some formidable problems. Digital computer techniques have been applied to displacement processes in which the capillary pressure has been included.5"8 More recently, similar techniques have been used by Blair 9 to calculate countercurrent imbibition behavior. The fact that imbibition behavior is described by the usual fluid flow equations (Darcy's Law and continuity equation) implies that the derived scaling laws should apply equally to this situation. Use of model experiments to study imbibition has been employed by Graham and Richardson 10 and Mattax and Kyte,11 who actually tested the scaling law applicability. This study is concerned with scaled model imbibition experiments on water-wet carbonate rocks. Of particular interest is the slowly rising water table experiment. This simulates a highly fractured reservoir with the water table rising uniformly through the vertical fracture system. Experiments were performed on different sized samples and with different rates of rise of the water-oil interface surrounding the rock pillar. Total immersion imbibition experiments on smaller rock samples were performed to test the basic linear scaling laws and to see if these simpler tests could be used to synthesize the rising water table experimental results. THEORY IMBIBITION SCALING LAWS Scaling laws for the flow of two incompressible immiscible fluids in a porous medium have been presented by Rapoport.12 These are derived directly from Darcy's Law for the individual phases and the continuity equation. Results from a laboratory model experiment will duplicate those from some reservoir prototype if a constant proportion is maintained among the three forces acting on the fluids — the capillary pressure gradient, the gravitational gradient and the flowing pressure gradient. Operation of the model (i.e., fluid injection or withdrawal) must be conducted in accordance with specific equations. If the

Jan 1, 1967

By W. L. Phillips

The plastic properties of lithium fluoride and magnesium oxide under compression were investigated in the temperature range 25° to 1000°C. At the higher test temperatures, the critical resolved shear stress and the rate of work-hardening of both materials decreased. At the same time, the number of stress lines decreased and the individual stress lines became wider. The density of dislocations decreased for a given strain the higher the test temperature for lithium fluoride. The decrease in the critical resolved shear stress as a function of temperature could be fitted by the equation 7 = Toe-KT. THE influence of temperature on the stress-strain curves of a variety of metal single crystals has been studied for a wide range of temperature.1"5 In general, it has been found that both the critical resolved shear stress and the rate of work-hardening decrease rapidly with increasing temperature and fall to a value of essentially zero well before the melting point is reached. AS the test temperature is increased, the density of slip lines has been found to decrease, while the width of the individual lines increases. Recently, Gallagher,' Graf et al.,7 and Pate1 and Alexander8 have found that single crystals of germanium and silicon, which have a covalent bond, can be plastically deformed at elevated temperatures. In compressing germanium it has been found that the strain-hardening coefficient decreased very rapidly as the temperature was increased. The coefficient did not tend to zero, however, as the melting point was approached. The plastic properties of ionic crystals at elevated temperatures have not been extensively investigated. In the only work previously reported Tamman and salge9 and Theile10 have shown that the yield point of sodium chloride single crystals tested in tension and compression decreased slowly with increasing temperature, falling to zero at the melting point. As the temperature was increased, they found a substantial increase in the amount of plastic deformation that could be sustained before fracture; and at temperatures above 400°C in tension tests there was an obvious necking which produced local extensions of up to 3000 pct. The purpose of the present work is to extend the knowledge of high-temperature deformation to the ionic crystals, lithium fluoride and magnesium oxide. The following were investigated: 1) The gross shape of the stress-strain curve at several temperatures. 2) The change in the critical resolved shear stress as a function of temperature. 3) The appearance of slip bands and the density of dislocations as a function of strain and temperature. EXPERIMENTAL TECHNIQUES The lithium fluoride and magnesium oxide used in this investigation were purchased from the Harshaw

Jan 1, 1961

By H. A. Bedworth, W. H. Bassett

The amount of oxygen present in refined copper bears an important relation to the effects of various impurities on physical properties of copper, as well as the effects of reducing gases at higher temperatures. It seems fitting at this time, when the effects of reducing gases on copper are being discussed, to describe methods that have proved satisfactory for the determination of oxygen and sulfur, and to present some results obtained by investigation of these methods in the authors' laboratory. The procedure for the determination of sulfur is closely interrelated with that for oxygen and has, therefore, been included. It was first proposed by Hampe1 that oxides in copper could be accurately determined by the loss in weight sustained by finely divided copper when reduced at red heat in pure hydrogen, or by the weight of water produced. Hampe's method was later modified by Archbutt,2 who established the accuracy of the method and demonstrated that equally accurate results were obtained by noting the loss in weight or by weighing the water formed. The determination of oxygen by heating in carbon monoxide has been proposed by West.3 In our hands this method has given slightly lower results than obtained by heating in hydrogen. Heath4 found that the loss in weight after heating in hydrogen did not represent the true oxygen as cuprous oxide but included also gases derived by the metal from the fuel and refining in the furnace, and any trace of mechanically held moisture. He found, further, that the copper after ignition retained hydrogen equivalent to about 0.01 per cent. Heath proposed to determine the amount of occluded gases by preliminary ignition for 20 min. in pure carbon dioxide—and to correct the error caused by absorbed hydrogen by subsequent ignition and cooling in carbon dioxide, finally replacing this gas with air.

Jan 1, 1926

By Henry F. Adams, Guy H. Ruggles

IN this paper the authors aim to chronicle the experience and salient points brought out in changing flotation reagents at a concentrator which had probably been using a mininium amount of oil at a minimum cost per ton, to a more complicated system requiring a partial chemical control. The original oils were coal tar and pine oil. The new reagents are lime, xanthate and pine oil. It was found that there were no insurmountable difficulties and eventually the cost of the new reagents per ton of ore proved to be very little more than that of the old. LIME PLANT When the question of handling lime came up there were two propositions open: (1) to handle the lime dry; (2) to handle it wet in the form of an emulsion. Granting that a dry lime feeder would function properly, delivering lime uniformly, the chief objection was the dust that would be raised when these feeders were being charged or operated, as the only possible location was on a gallery beneath which men were working. With this objection the handling of lime as an emulsion seemed to be the better scheme. The lime plant which was first installed was for experimental work on one section. This was gradually changed and developed until it was of sufficient size to accommodate 20 sections. The various changes will not be discussed and the following description deals only with the fully developed plant. Crude as it is, and perhaps somewhat expensive to operate, the lime-handling plant has been quite successful. Much has been learned which will pave the way for a better installation in the future. Burnt lime is received loose in standard gage box cars. This is the product of the kilns and has had no screening or sorting. A grab sample is taken from each car as it is unloaded. An average of the analyses of samples from 44 cars gave the following: [ ]

Jan 1, 1928

By Francis P. Sinn

IN the zinc smelting industry the year 1947 seems to have been one of putting one's house in order rather than one of any material technical development or radical change in operating conditions. Labor generally has been in better supply but several plants report a scarcity of skilled workmen. Some plants continue to operate on the basis of a six-day week and will probably continue to do so until labor is more plentiful. Only one plant is known to have operated on a curtailed basis because of labor shortage, but here the difficulty was lack of proper housing facilities. Necessary materials and equipment for much-needed maintenance and modernization have been in short supply so these programs have often been delayed. Laborsaving devices of the "Payloader" type have been more generally used for handling materials. Slab zinc production was discontinued during the last months of the year at Danville, 111. and at Langeloth, Pa. Both of these plants used the Hegeler type of furnaces fired with producer gas. It is understood that the rolling mill and possibly the acid plant at Danville will continue to operate. At Langeloth acid will be produced from

Jan 1, 1948

By F. R. Archibald, C. M. Nicholson

The present paper may be considered complementary to an earlier contribution on the same subject by F. R. Archibald and C. F. Jackson.1 It is particularly concerned with engineering and technological aspects of the operations at the Harleyville Alumina Plant during its period of operation from January 1945 to July 1946. The plant was built for and operated by Ancor Corporation, at Harleyville, South Carolina, as part of the government sponsored wartime program related to alumina production from domestic raw materials. The main purpose of the program was to secure technical and engineering data, based on actual plant experience, that might serve as a foundation for large scale production of alumina from raw materials other than bauxite. The Harleyville plant was directed specifically to treatment of clays found in very extensive deposits in the Carolinas and Georgia using the lime-sinter process developed by Ancor Corporation. It is considered that the purpose stated above has been served and this paper is to record and discuss some of the more important findings. The main factor in location of the plant at Harleyville was the presence in that locality of a rather remarkable deposit of high calcium limestone. The clay mining operation was centered near Aiken, S. C., and although a rail haul of ninety miles was involved there were, at the time, factors favorable to the Harleyville location offsetting, in part, the cost of transportation of clay, There are, no doubt, locations in the general area where clay and limestone deposits may be found in closer proximity hut they had not been proven up when the project was undertaken. Availability of power from the Santee-Copper development whose high tension line skirted the Property; ready access to rail and highway transportation; the promise, realized in actuality, of ample supply of soft water; and availability of labor supply were other factors of importance. Moreover, the general area has the decided advantage, for this type of operation, of a mild climate. Construction was begun in August 1943, and although stopped for a time priding review of the general situation that fall, it was resumed, albeit with less urgency, and substantially completed by the end of 1944. The total capital cost was approximately $3,460,000 The first alumina was turned out in April 1945 and from then until the plant was closed down in July 1946, the operations followed a succession of periods of production alternating with periods in which minor alterations were made in conformity with experience. Steady improvement was made and at the time Operations were discontinued it was considered that experience and the necessary engineering were in shape for removal of the remaining bottlenecks and a somewhat major revision in one section of the plant. Unfortunately this could not be carried out and it was necessary to discontinue the

Jan 1, 1949

By K. A. Natarajan, I. Iwasaki

The influence of dissolved oxygen and the Pt - Pt-O reaction on the measurement of redox potentials in solutions containing ferrous-ferric couple was examined. Current-potential curves were used to illustrate the shift in measured potentials toward the oxygen potential in oxygenated and deoxygenated systems at low concentrations of ferrous and ferric ions. The ranges of concentrations of the ferrous-ferric couple, in which the interference from oxygen and the platinum-oxygen reactions becomes significant, are illustrated through the mixed potential mechanism.

Jan 1, 1975

By Dale Dixon, A. R. MacPherson

The present comminution process in principle has remained more or less the same for the last 50 years. The majority of the changes have been in the fields of equipment improvements and size increases of prevailing systems. The development and utilization of completely new systems has virtually been non-existent. As energy and steeel costs increase and lower grade ores are mined, the comminution costs per ton of ore treated must improve accordingly or the operations will not be profitable. The chapter examines further developments in existing systems and touches on relatively unexplored methods of comminution appropriate for future needs.

Jan 1, 1982

By A. H. Geisler, R. F. Mehl, S. Barrett

The studies of the mechanism of pre= cipitation and of the resulting property changes in aluminum-silver alloysl-3 have presented some new concepts of the aging reactioxl—concepts that may be fundamental in establishing a complete quantitative theory of age-hardening. With both aluminum-copper and aluminum-silver alloys, thin platelike aggregates form parallel to the Widmanstätten planes of precipitation.l,4 These platelets grow in lateral dimensions and in thickness with aging time until they arc thick enough to produce an X-ray diffraction line pattern. Their structure is that of a transition lattice which is coherent with the matrix, since the atomic spacings in the matrix and the precipitate are the same on each side of their common interface.2,4 The equilibrium precipitate forms later from and at the expense of the transition lattice. Since age-hardening occurs during the formation and growth of the transition lattice, the major contributor to the hardening no doubt is the stress condition in the matrix resulting from the matrix holding the precipitate in the coherent condition. The development of these stresses also appears to be responsible for an increase in the electrical resistance superimposed on the normal decrease resulting from a change in the concentration of the matrix during aging.3 The two consecutive reactions constituting the aging process are accompanied by characteristic microstructural alterations. The initial precipitation process results in the formation of a Widmanstatten figure, while the later transformation of the transition lattice to the equilibrium lattice is accompanied by a coalescence, in the case of aluminum-copper alloys,5 and by the appearance of light areas at the grain boundaries with aluminum-silver alloys showing a structural rearrangement of matrix and precipitate.3 This latter reaction is similar microscopically to the so-called "discontinuoils precipitation." Possibly discontinuous precipitation is a process that often if not always follows true precipitation of a coherent lattice and during which the transformation of the coherent transition lattice to the equilibrium lattice takes place accompanied by matrix recrystallization.3 Expermental Procedure The alloys were made using 99.97 per cent A1 or distilled magnesium, with

Jan 1, 1943

By R. F. Mehl, A. H. Geisler, S. Barrett

The studies of the mechanism of pre= cipitation and of the resulting property changes in aluminum-silver alloysl-3 have presented some new concepts of the aging reactioxl—concepts that may be fundamental in establishing a complete quantitative theory of age-hardening. With both aluminum-copper and aluminum-silver alloys, thin platelike aggregates form parallel to the Widmanstätten planes of precipitation.l,4 These platelets grow in lateral dimensions and in thickness with aging time until they arc thick enough to produce an X-ray diffraction line pattern. Their structure is that of a transition lattice which is coherent with the matrix, since the atomic spacings in the matrix and the precipitate are the same on each side of their common interface.2,4 The equilibrium precipitate forms later from and at the expense of the transition lattice. Since age-hardening occurs during the formation and growth of the transition lattice, the major contributor to the hardening no doubt is the stress condition in the matrix resulting from the matrix holding the precipitate in the coherent condition. The development of these stresses also appears to be responsible for an increase in the electrical resistance superimposed on the normal decrease resulting from a change in the concentration of the matrix during aging.3 The two consecutive reactions constituting the aging process are accompanied by characteristic microstructural alterations. The initial precipitation process results in the formation of a Widmanstatten figure, while the later transformation of the transition lattice to the equilibrium lattice is accompanied by a coalescence, in the case of aluminum-copper alloys,5 and by the appearance of light areas at the grain boundaries with aluminum-silver alloys showing a structural rearrangement of matrix and precipitate.3 This latter reaction is similar microscopically to the so-called "discontinuoils precipitation." Possibly discontinuous precipitation is a process that often if not always follows true precipitation of a coherent lattice and during which the transformation of the coherent transition lattice to the equilibrium lattice takes place accompanied by matrix recrystallization.3 Expermental Procedure The alloys were made using 99.97 per cent A1 or distilled magnesium, with

Jan 1, 1943

PERSONAL (Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who registered at Institute headquarters during the period June 10 to July 10: J. C. Ralston, Spokane, Wash. E. P. Ashmore, So. Porcupine, Ont., Can. William H. Yeandle, Jr., Mexico City, Stuart Croasdale, Denver, Colo. Mexico. W. E. Hopper, Houghton, Mich. W. C. Minsch, Mexico City, Mexico. D. W. Brunton, Denver, Colo. H. V. Winchell, Minneapolis, Minn. Fred Crabtree, Pittsburg, Pa. W. G. Swart, Denver, Colo. Robert S. Lewis, Salt Lake City, Utah. D. F. Schindler, Madison, Wis. Noel Cunningham, Timmins, Ont., Can E. R. Pettebone has just been elected a Trustee of the Pennsylvania State College, being supported by the votes of the delegates of the Pennsylvania Anthracite Local Section of the Institute and the Engineers' Society of Northeastern Pennsylvania.

Jan 8, 1914

By Lawrence Wright

ON the steep slopes of the Kootenays, 15 to 20 miles south of Nelson, B. C., are a number of ore occurrences (Fig. 1). One that has many features of mining and geological interest is the Ymir Yankee Girl Gold Mines Limited. Discovery of this property was made in 1899 at an outcrop on the hillside, some 2500 ft. above the village of Ymir. This proved to be a branch vein 20 ft. long leading to two main veins, the Yankee Girl and the Spur (Fig. 5). The ore pattern as now delimited shows a remarkable increase in ore area with depth below the outcrop. This recent development is of interest particularly in view of the fact that the property was nearly con-demned, professionally. Another interesting feature, which has a bearing upon its history, is the persistent excess of tonnage produced from period to period over visible reserves. This is not ascribed to lagging mine development, but to detailed vein characteristics, which we will endeavor to make clear by giving a description of the veins and their surroundings.

Jan 1, 1938

By E. P. Klier

The work of Klier and Lyman1 on the bainite reaction has led to the full description of this reaction for medium-carbon low-alloy steels. Certain experimental data reported by Klier and Lyman appear, however, to be improbable of obtaining in very high-carbon steels. The study herein reported consists of an analysis of the transformation characteristics of a 3 per cent chromium, I per cent carbon steel by means of X-ray and metallographic methods. From the results obtained it is concluded that the bainite reaction in this steel is more complicated than that reported by Klier and Lyman for the low-carbon low-alloy steels. Henever, the mechanism of bainite formation in this steel appears to be essentially the same as proposed for the low-carbon low-alloy steels with the modification that the first volumes to transform are carbon-rich rather than carbon-poor. Experimental Procedure The analysis of the steel studied was: Cr, 2.89; C, 1.02; Mn, 0.33; Si, o.35; S, 0.012; P, 0.020. The stock was received from the Carpenter Steel Co. in rolled bars. Specimen Preparation Specimens were austenitized at 1200°C. (2192°F.) for 25 min. in purified nitrogen. The resultant A.S.T.M. austenite grain size was 0-1. Isothermal transformation was allowed by quenching the specimens into liquid metal baths controlled to 5°C. at 540°C. (1004°F.) and above, and to 2°C. at 490°C. (914°f.) and below. Following the desired degree of transformation all specimens were water quenched. Metallographic Examination Specimens 1/4 in. round by 1/4 in. were used for nietallographic examination. Etch-ants used were Vilella's reagent (I gram picric acid, 10 ml. hydrochloric acid to make 100 ml. ethyl alcohol solution) and alkalinc sodium picratc (electrolytic). Vilella's reagent was effective in revealing all microconstitucnts, while the alkaline sodium picrate developed the carbon-rich structures or carbides only. X-ray Examination Two X-ray techniques were used—the Debye-Scherrer method and a back-reflection method. 'The small specimens necessary for the Debye-Scherrer method were austenitized and then allowed to transform, or were cut from the larger metallographic specimens. The metallographic specimens were used for the back-reflection X-ray analysis. When it was desirable to determine the structure of the carbide present, sliver specimens were electrolytically etched to develop a carbide coating, then were exposed in the cameras. This technique was frequently necessary to allow positive identification of the carbide.

Jan 1, 1945

By R. C. Rastogi, F. F. Aplan

The goal of this study is to evaluate the coal flotation process and the interaction of the chemical (reagent) and hydrodynamic (machine, operational) variables as they affect yield, flotation of various sized particles, and sulfur and ash rejection. Coal flotation is found to follow a first order process with the coal floating much faster than either pyrite or ash. This circumstance may be used to achieve gangue rejection during flotation. When floated with MZBC, cresol, or pine oil frothers, coal floats in the size sequence: 108 pm ( - 65 mesh), 589 x 808 pm (88 x 65 mesh), and 1.17 mm x: 589 pm (14 x 18 mesh). However with a substantial amount of fuel oil collector, all particles tend to float roughly in proportion to their content in the feed. An increasing aeration rate was found to be the most important variable in increasing the coal flotation rate. This increase in flotation rate, unfortunately, is also accompanied by an increase in the flotation rate of the pyrite. The rejection of pyrite during coal flotation is best accomplished at low aeration rates, low frother concentrations, and low impeller speeds.

Jan 1, 1986

On Apr. 21, the Victory Liberty Loan was offered to the public. This Loan is made necessary by the expenditures incident to closing of the war. As in preceding Liberty Loans, an intensive campaign is being conducted, and this Committee is to obtain and record subscriptions from the Industry of which you are a part. I am sure you feel as I do in wishing the Mining Committee to make as good a showing as possible. By placing or recording your subscription through us will help your Committee to make its proper showing, and, as heretofore, your transaction can he carried out with any bank or trust company you may prefer to designate. Payment may be made in full or in six instalments. In either case, 10 per cent. will be required on or before May 10. Subscription blanks will be mailed to you as soon as available. CHARLES HAYDEN, Chairman.

Jan 5, 1919