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By Bernard York, John J. Reed

J. P. Zannaras (U.S. Tungsten Corp., Congress, Ariz.) —In the investigation described in the paper by Bernard York and John J. Reed, the 8x8x8-in. square block was subjected to compressive forces from three sides, top, side, and rear. Let us refer to the stresses set up by these forces as Sz due to top pressure, Sy due to side pressure, and Sx due to rear pressure. At the section across the 2-in. hole (when failure occurred at 317 psi) the compressive stress Sy was equal to 317 x 8/6 = —422 psi, the top compressive stress S; is of the same intensity, —422 psi, and the rear compressive stress S, equals —317 psi. The true stress is T = Sy — S — S Taking as 0.2,* Taking the case when the opening was ½ in. and failure occurred at 517 psi, 8 Sy - 517 x -----= —537 psi 7.5 8 Sz = 517 x-----= —537 psi 7.5 Sx = —517 psi The true stress T = Sy — Sz — S, T - —537 + 0.2 x 537 + 0.2 x 517 = —327 psi. It can be shown that the above fundamental formula holds good not only for the above two examples but for all sizes of openings used, because when this formula is expressed in terms of the external pressure and size of the opening it agrees perfectly with the experimental results obtained by the authors and given in Fig. 12 of their paper. General formula: T = Sy — s: — S....

Jan 1, 1955

By KENNETH CITTISGHAM

During the year 1945, the total number of wells drilled in Ohio, including the. non¬productive wells, was 1034. For the 10-year period ending with 1945, the average completions per year were 1125, the least number being 910 in 1938, and the maximum 1561 in 1941. The proportion of dry holes in 1945 was 37 per cent?about the same as for the year 1944 but exceeding the 10-year average, which was 34 per cent. The number of oil wells completed exceeded the number drilled in 1944 by about 30 per cent, the average initial per well being the same in both years. Gas-well completions were approximately 10 per Cent less than in 1944, with the average initial per well about 5 per cent greater. The difference in number of oil and gas wells in the two years was in Berea and Clinton completions, as the number of oil wells increased about 30 per cent, owing to greater activity in the two sands named, while the number of gas wells decreased because of fewer completions therein.

Jan 1, 1946

By J. L. Wright

When management is confronted with the risk of constructing a waste disposal well, these are some of the questions which may arise. Should the company expand the present waste treatment plant? More lagoons will cut into valuable acreage which might be needed later, and yet the pollution engineer says he can guarantee results. On the other hand, does the formation being used for those successful disposal wells off to the west extend over far enough to be used for the company's own well? Will the formation be thick enough? Will it be too deep? Will it be porous and permeable enough? Apart from needing to make a profit on the products made at the plant, plant officials must sometimes act under pressure to comply with pollution standards. The manager must build the cost of the pollution control system into the price of the products made by the company.

Jan 1, 1970

By L. W. Rowe, S. S. Cole

A laboratory bench scale unit is described whereby finely divided chlorinatable residues are held for a short period by a restraining bed of a coarse-grained ore of comparable composition to permit 'flash' chlorination of the high surface area powder. Results on chlorinating a finely divicled titania residue using rutile sand as the restraining bed showed that 92 pct utilization of chlorine and equivalent conversion of TiO2 in the fine residue to Ticl4 were attained with a dust loss of about 3 to 4 pct and an equivalent amount of ch1om'nation of the titanium values in the restraining bed. THE chlorination of coarse grain titaniferous ores; i.e., 20 to 150 mesh sizes in fluidized beds is practiced commercially.' One effective method found for the chlorination of a very fine material in a fluidized bed is the "flash" chlorination technique.' By charging the finely divided charge material into the bottom of an established bed of optimum sized rutile, ilmenite, titanium beneficiate, or even an inert material such as sand, chlorination occurs before the dust can pass through the bed. The major requirement is that the bed be less chlorinatable than the charge. In this process, the charge consists of a finely divided (between one and 50 µ) titania residue obtained from a titaniferous ore beneficiation process. The charge is blended with a 20 pct wt basis addition of 20 to 60 .mesh size low volatile coke (to minimize hydrogen chloride formation) and fed to the bottom of the bed with the chlorine gas stream. A ball check device is used to permit entry of the charge and prevent the bed from discharging when the gas flow is cut off. The coarse pieces of coke serve to reduce compaction in the charge mixture and permit sat]sfactory feeding without plugging or jamming. Feed and gas rates are adjusted to provide for complete reaction of the charge material, with 90 to 95 pct chlorine efficiency, and maintain a gas flow in the range of 0.4 to 0.6 ft per sec. The equipment consisted of a 3-in. diam mullite tube enclosed in an electric furnace. A bow-shaped 3/4 in. Saran tube fed the charge from an air lock type of feed hopper (to prevent the escape of the chlorine gas into feed bin) to the bottom of the bed. The charge rate was set by providing a small awiliary hopper below the feed hopper where a weighed portion of the charge could be discharged in a specified time interval into the main chlorine stream. The chlorine rate was measured by a flowmeter. The reaction tube was filled with a bed of Australian rutile ore, this restraining bed serving two purposes; i.e., it rapidly heated the fresh charge to the reaction temperature and retained the particles in the bed for a sufficient time for selective chlorination to proceed. Due to the fine particle size and open, porous structure of the charge, this reaction was almost instantaneous, and, with proper adjustment of feed and gas rates, very little fine material passed through the bed without reacting and only a very small fraction of the restraining bed was chlorinated. A typical reaction procedure was to fill the bench scale fluidized bed unit with a 1 kg charge of Australian rutile ore analyzing 95.5 pct TiO2, 0.6 pct FeO, a beach sand deposit 40 to 150 mesh size. When fluidized, the bed was approximately 2 ft in depth. The ore was fluidized with a 1:l mixture of chlorine and nitrogen at a rate of 0.40 ft per sec. This gas mixture was necessitated by the comparatively short bed depth; a larger unit, with a deeper bed, could be fluidized with chlorine alone without significant free chlorine loss. Feed rate was 8.0 g per min of beneficiated ilmenite analyzing 85.0 pct TiO2, 2.6 pct FeO plus 1.6 g per min of 20 to 60 mesh petroleum coke. The

Jan 1, 1962

By AIME AIME

MEMBERS of the Engineering Education Committee held two meetings at Joplin preliminary to the opening of the main meeting there. The first was held on Sunday afternoon. It was attended by all who had arrived early enough and as among the dozen or' fifteen who were present the heads of a half dozen schools of mines were included it was a representative gathering. C: H. Fulton, chairman of the Committee presided and T. T. Read acted as secretary of the meeting. The chair., man reminded those present that last year there had been some discussion as to the advisability of the proposal, made by Edward Steidle, that a, separate society, devoted to education in the mineral industry, he organized. Many .people had felt that there are already so many societies in existence to demand one's time and attention, that it would be a mistake to add to their number and the counter suggestion had been made that the work of this committee could be so reorganized as to meet all the needs that a separate society could fill. He therefore presented for discussion these four' questions: (1) Shall a subcommittee .be appointed to study, and report in February, 1932, the possibility of the reorganization of the work of the Engineering Education Committee into the equivalent of an' Institute division; (2) if the work is so reorganized what shall be the relation of the work of the Committee (division) to the work of the-Society for the Promotion of Engineering Education; (3.): what are the, cardinal objectives of education for the mineral industry; and (4) what should be done as regards the movement in some institutions to plan their work-in the light of that being done in other institutions, for example, in geophysics?

Jan 1, 1931

By G. A. Beske, P. Hilsch, J. Wulff

The effects of the growth precipitates on the su-perconduching properties of an Al- 15 al. pel Zu alloy have been studied using magneization, transition lem-perature, and residual resistivity measurements. Aging at 230C for 1/2 to 11 he produces an increase in Hfp, Ike field of first penetration, and tut increase in trapped flux. The upper critical field, Hc2 remains constant for such aging tunes. Aging at 200°C produces a decrease in Hfp and an increase in trapped flux. The transition temperature remains constant at Tc - 1.227° ± 0.02°K for aging at 220°C for tims of from 1/2 to 10 hr, and for aging at 200°C it remains constant at Tc. = 1.18° i 0.02°K for times from 1/2 hv to 26 hr. The observed behavior indicates that the superconducting matrix when aged at 220°C behaves tike a type U su-perconducior, but when aged at 200°C behares like a type I superconductor. The magnetization changes after aging can be attributed to the growth and clutnge in distribution of the precipitate in a matrix of fixed composition. IT has been realized for some time that the superconducting properties of alloys are highly structure-sensitive. This is evident in the work of Mould and Mapother1 who examined the properties of an aluminum alloy. Precipitation effects have also been briefly mentioned in other studies.2-4 Bonnin and coworkers5 have observed a sharp inc rease in trapped flux in an A1-Mg alloy when the residual resistivity reaches a value that indicates it is a type II superconductor. Recently Blanc, Goodman, and Nemoz5p have reported on precipitation effects in A1-Ag alloys. Detailed studies of precipitation in Pb-Sn and Pb-Cd alloys made by Livingston6 serve to show that the upper critical fields are enhanced by quenched-in solute. Furthermore. at various stages in the precipitation process? the upper critical field is determined largely by the remanent solute. The observed magnetic hysteresis and trapped flux in such alloys result from the interaction between precipitate and the flux filaments in the mixed state. The flux trapping appears to depend largely on the precipitate distribution and is greater if the superconductor is type II than if it is type I. To examine the effect of precipitation in another alloy system, particularly one in which the composition of the superconducting phase does not change significantly during the course of precipitation, the Al-Zn system seems interesting, especially in view of the transition temperature and resistivity studies of Chiou and seraphim.' Furthermore, the recent detailed electron-microscope studies of an Al-Zn alloy by Richards and Garwood8 provide a guide for relating superconducting properties to changes in structure. For these reasons, magnetization, transition temperature, and residual resistivity measurements for varying times of heat treatment at two temperatures were made with a -15 at. pct Al-Zn alloy. The results are reported in this paper. I) EXPERIMENTAL The alloy used was prepared by Cominco Products Inc. from 99.9999 A1 and 99.999 Zn. It was chill-cast, swaged, and drawn to 0.125-in.-diam rod. The analyzed composition was 15.6 at. pct Zn (31.1 wt pct). A jeweler's saw was used to cut the 0.125-in.-diam rod into the 0.875-in. lengths needed for magnetization measurements. The ends of the cylinders were slightly beveled to remove the sharp edges. A portion of the original 0.125-in.-diam rod was drawn into 0.010-in.-diam wire and used for transition temperature measurements. Specimens were suspended from wires within a vertical furnace during heat treatment. All were homogenized at 500°C for a minimum of 3 days and subsequently solutionized for times in excess of 6 hr. The solutionizing temperature was held constant to +3°C. Individual specimens were homogenized, quenched, and aged several times and no effects indicating loss of zinc were noted. The suspended specimens were quenched by cutting the wires and allowing the specimens to fall into a silicone oil bath held at the aging temperature. They were then isothermally transforked by aging in the same bath used for quenching. After aging for the required time (approximately 10 min aging was necessary before the upper critical field reached a fixed value), they were briefly (1 to 2 sec) dipped into an acetone bath at room temperature to remove adherent oil and then immediately transferred to liquid nitrogen where they remained until inserted into the helium bath (usually within an hour). The temperature of the aging bath was held constant to +3°C for longer aging times. The cryostat used for the measurement of superconducting properties consisted of outer and inner dewars for liquid nitrogen and liquid helium, Stokes 6-in. booster diffusion pump and Stokes Model 212 mechanical pump, temperature controller to measure and control the temperature of the helium bath, and a superconducting solenoid with inserted search coils to provide the magnetic field and measure the magnetic moment of the specimens. A schematic diagram of the cryostat is shown in Fig. 1. An ultimate temperature of 0.85°K was reached with this apparatus. The temperature controller used is similar to the one described by Blake and chase.' A 0.5 pct Allen-Bradley carbon resistor and a nichronle heater (200

Jan 1, 1968

By C. WIFLARD HAYES

(New Haven Meeting, February, 1909.) I DESIRE to make it perfectly clear at the outset that I fully realize the hazardous nature of any attempt to estimate the quantity of iron-ore or any other mineral in the ground. I should not have had the temerity to venture upon an inventory of the iron-ore supplies of the United States except for the requirements of the Conservation Commission. During the preparation of this inventory I have been impressed by the wide diversity in estimates of those best qualified to. hold an opinion, and I am therefore prepared in advance for criticism of my figures. Inasmuch as this report was prepared in large part for unprofessional readers, I considered it necessary to classify and describe the commercial iron-ores in a somewhat elementary manner, in order to explain the reasons for the large element of uncertainty in the estimates. I have therefore given a chemical and a geological classification of iron-ores, which place the commercial deposits in six classes: (1) magmatic segregations in basic igneous rocks; (2) contact-deposits formed in connection with igneous intrusions; (3) concentration-deposits; (4) replacement-deposits; (5) bedded-deposits, and (6) gossan-deposits. The iron-ores are further distinguished under two classes available and not available. This classification is in large measure arbitrary, and it, is evident that it will vary front time to time. In the available class are placed those ores which can be worked at a profit under conditions essentially as they exist at present. Since it depends wholly on the question of costs, the various factors which affect cost will determine the classification of any particular deposit. Actual production, * Abstract of Report prepared for the Conservation Commission. t Chief Geologist, United States Geological Survey. .

Apr 1, 1909

When the writer first began his search for the early history of coal he was amazed at the paucity of information in literature about it, and while after six years many of the reasons for such a scarcity are understood, there are still many cases, even within the last two centuries, when one who can appreciate the tremendous part coal has played in the development of modern times, finds it hard to realize how little attention was paid to this material in those early clays. Occasionally a traveller or observer is found who foresaw how valuable coal was to be when industries were developed, but these were few and to most of those recording its occurrence it was just another mineral. George Washington was farsighted in his view of the development of this country and the need for means of transportation across the mountain barrier, but it was at least sixteen years after he must first have known of coal before he made any reference to it in his journals. He did, however, knowingly or not, select some valuable coal properties in the lands lie obtained in the West. This was then almost entirely an agricultural country, and what industries there were found a great abundance of wood fuel within easy access, there were no steam plants, and all iron was made with charcoal; in fact, the "captive mines" of the iron industry then were large timber "plantations," and when these were exhausted the furnace usually was abandoned and another one built elsewhere, as transportation of charcoal was quite expensive. Along the seaboard the cities and industries began to import coal from England and Nova Scotia early in the eighteenth century, but until the war of the Revolution began the total quantity of coal used yearly in this continent did not exceed nine thousand tons. In 1800 only two places, Pittsburgh and Richmond, Virginia, were using coal to any extent for domestic purposes and it was much later. than this that the amount of coal used in Philadelphia, New fork, and Boston exceeded that of wood. Practically all of the early travellers and writers mentioning coal are noted in the following pages. Several Englishmen who were evidently familiar with its use and value at home, mention its presence as being of great future promise to the young nation, but to nearly all it was more or less of a curiosity and the smoke caused by its use an abomination, and it

Jan 1, 1942

By B. L. Averbach, M. F. Comerford, M. B. Rough

The volume fraction of ß phase was determined in a Ti-6Al-4V alloy by measurements of integrated diffraction intensities. The (0002), and (100)ß diffraction lines were chosen because this combination minimizes the errors resulting from preferred orientation. The difficulties arising from fluorescence radiation were eliminated by use of a diffracted beam monochromator. A specimen quenched from 1475OF (800°C) contained approximately 5 pct ß, but in specimens quenched from higher temperatures no ß was found. The ß phase formed during aging, and in specimens solution treated at 1570oF (855oC) approximately 10 pct ß was present after aging at 1000°F (540°C) for 24 hr. This ß appears to form by decomposition of martensitic a'. ThE kinetics of the reactions which occur during the heat treatment of titanium alloys are complex ' and not completely understood. It has been proposed that hardening occurs in some alloys' on aging by the precipitation of a transition phase w followed by the formation of the stable a and ß phases. It has been proposed for other alloys2 that the a' marten-site decomposes by precipitating finely dispersed a particles. Most investigations have been hampered by the difficulties of determining quantitatively the amounts of the various phases present. This paper is concerned with the measurement of the amount of ß phase by an X-ray method, similar to one developed for the determination of retained austenite. The principal new feature was the use of a mono-chromator in the diffracted beam in order to reduce the fluorescence arising from the sample. EXPERIMENTAL PROCEDURE The experiments were carried out on an alloy of nominal composition Ti-6Al-4V (actual weight percentages: 6.2 Al, 4.1 V, 0.02 Mn, 0.17 Fe, 0.005 H, 0.03 C, and 0.02 N). The material was received as 5/8-in.-diam centerless ground rods in the annealed condition. The heat treatments were carried out in a vacuum of approximately 0.03µHg. The X-ray intensity measurements were made on 3/8-in. thick discs. The surface was prepared by grinding off about 0.060 in. and electropolishing in a solution af 60 ml (70 to 72 pct) perchloric acid in 1000 ml glacial acetic acid with a current density of 0.5 amp per sq cm.q The X-ray determination is based on the proportionality of the diffracted intensity of each line to the volume fraction of the corresponding phase. In calculating the intensities for a powder sample it is assumed that a large number of grains con- tributes to the diffracted intensity and that the grains are oriented at random. The presence of preferred orientation introduces serious errors in the relative intensities. The material used in this investigation exhibited a strong preferred orientation, which could not be removed by heat treatment. Other investigators have also found that preferred orientation may be retained after phase transformations. Glen and pugh5 performed a detailed analysis of the randomness expected after several allotropic transformations, but stated that this is not observed. Burgers,6 and Burgers and Ploos van Amstel,7 found that, in zirconium, the original orientation is retained after two phase transformations. Newkirk and Geisler8 observed similar behavior in titanium. On the basis of this evidence, it appears that, in the absence of plastic deformation, textures present in annealed titanium alloys are retained. Heating an a-ß alloy to the all-ß region and subsequent cooling to room temperature do not make the orientation of the mar-tensite different from that of the original a phase. In the present investigation it was possible to take advantage of the crystallographic relationships involved in the martensitic transformation to minimize the errors associated with preferred orientation. The relative orientation for titaniu-m marten-site9 takes the form (0001), 11 (110)ß; [1120], 11 [lll]ß. The same relationship has been proposed for zirconium' and certain titanium-base alloys.10-12 Additional sets of approximately parallel planes have been determined for titanium-nickel alloys." The influence of preferred orientation can be minimized by comparing intensities from parallel planes in the two related phases. If it is assumed that each family of planes in a given phase is equally well populated, the effect of preferred orientation can be eliminated by using the normal multiplicity for the family of planes since each set of parallel planes is equally preferred for any orientation of the sample relative to the X-ray beam. The most suitable combination of reflections in the Ti-6A1-4V alloy appeared to be (0002), and (110)ß It must be recognized that the ß formed during aging of the Ti-6A1-4V alloy is a precipitate rather

Jan 1, 1960

By L. E. Shiffman

W. J. Parton—Those operators faced with the problem of treating fine coal whether in bituminous or anthracite will find this paper most timely. I would like to take this opportunity of discussing Mr. Schiffman's paper and at the same time express certain views relating to our Tamaqua plant. I would like to ask the author what type of impeller and diffuser is used in the Denver cells? Screen analysis of products from individual cells indicate that coarser material resists flotation and only floats after greater retention time in the last few cells. Also, the need for a scavenger screen to reclaim non-floated coal particles further stresses this point. I have always felt that more efficient means of cleaning coal between 10-mesh and 28-mesh existed than flotation. Reagent and power costs are high for the flotation process. When floating +28-mesh particles, cell capacity is lowered and some of the particles are lost with the refuse. The Tamaqua plant of the Lehigh Navigation Coal Co. floats —28-mesh coal and capacity of recoverable coal is 40 tph for 1800 cu ft of Denver cells; or 0.05 tons per cu ft of cell. At Kimberly 7.75 tph for 600 cu ft of cell gives 0.013 ton per cu ft of cell. At Bessie 14 tph for 800 cu ft of cell gives 0.017 tons per cu ft of cell. It would be appreciated if the author would comment on what he feels is the upper size limit of particle to attain most efficient utilization of the flotation process. The dewatering screw is a very interesting development since it offers a simple way to prepare coal sludge for more complete clewatering by drainage or mechanical dewatering on screen or filters. In other words it could be used to accomplish the same thing as a thickener tank. I would appreciate having the author's comment on how he thinks such a screw dewaterer would work on a froth.* The process as used in floating coal at the Bessie and Kimberly plants may be referred to as more of a bulk oil float in contrast to a froth flotation process. Experiments on increasing capacity of cells is most interesting since we are going through such an experi- mental period at the present time. Recently a double overflow was installed on our No. 30 Denver cells. So far results are not conclusive. In reviewing this paper the following comments are made pertaining to investigation of methods for increasing capacity: Supercharging: Supercharged air in matte flotation or for that matter the use of the normal amount of air drawn in by the impeller would in all probability cause such an aeration in the cell as to destroy the buoyant effect given to the coal particles by the excessive amount of kerosine used. In other words, air creates an agitation zone throughout the cell, creating a boiling and thereby giving a lower recovery in the cell. It would be interesting to know whether the 7 pct increase in recovery was with no air being admitted to the stand pipe. Changing Impeller Speed: The speed of a receded disc impeller for a No. 30 cell as recommended by the Denver Equipment Co. is, I believe, approximately 250 rpm. At this speed and using supercharged air in excess of 8-oz pressure, we have observed a boiling action in the cells. In our flotation we endeavor to obtain some degree of froth flotation using pine oil as a frother. The boiling action as caused by increasing the amount of air added to the cells is detrimental to recovery in froth flotation. It is our belief that to obtain increased recovery from a cell in froth flotation, additional air must be introduced but at the same time this air must be dispersed throughout the pulp in the form of small bubbles and this can only be done by increasing the speed of the impeller. Therefore, if Mr. Schiffman decreased the speed of the No. 30 impellers and at the same time continued to use supercharged air, the boiling action may have been increased because larger bubbles developed. The lower recovery as reported could be due to this factor. Decreasing the impeller speed will definitely decrease the power consumed but may have other disadvantages. First, we believe it will permit "sanding" in the cell and this in our opinion will increase the wear on the impeller and diffuser, especially so, if there is pyrite and/or sand present in the feed. "Sanding" in the cell when air is used, as in froth flotation, will effect the dispersion of this air and cause boiling.

Jan 1, 1951

By L. E. Shiffman

W. J. Parton—Those operators faced with the problem of treating fine coal whether in bituminous or anthracite will find this paper most timely. I would like to take this opportunity of discussing Mr. Schiffman's paper and at the same time express certain views relating to our Tamaqua plant. I would like to ask the author what type of impeller and diffuser is used in the Denver cells? Screen analysis of products from individual cells indicate that coarser material resists flotation and only floats after greater retention time in the last few cells. Also, the need for a scavenger screen to reclaim non-floated coal particles further stresses this point. I have always felt that more efficient means of cleaning coal between 10-mesh and 28-mesh existed than flotation. Reagent and power costs are high for the flotation process. When floating +28-mesh particles, cell capacity is lowered and some of the particles are lost with the refuse. The Tamaqua plant of the Lehigh Navigation Coal Co. floats —28-mesh coal and capacity of recoverable coal is 40 tph for 1800 cu ft of Denver cells; or 0.05 tons per cu ft of cell. At Kimberly 7.75 tph for 600 cu ft of cell gives 0.013 ton per cu ft of cell. At Bessie 14 tph for 800 cu ft of cell gives 0.017 tons per cu ft of cell. It would be appreciated if the author would comment on what he feels is the upper size limit of particle to attain most efficient utilization of the flotation process. The dewatering screw is a very interesting development since it offers a simple way to prepare coal sludge for more complete clewatering by drainage or mechanical dewatering on screen or filters. In other words it could be used to accomplish the same thing as a thickener tank. I would appreciate having the author's comment on how he thinks such a screw dewaterer would work on a froth.* The process as used in floating coal at the Bessie and Kimberly plants may be referred to as more of a bulk oil float in contrast to a froth flotation process. Experiments on increasing capacity of cells is most interesting since we are going through such an experi- mental period at the present time. Recently a double overflow was installed on our No. 30 Denver cells. So far results are not conclusive. In reviewing this paper the following comments are made pertaining to investigation of methods for increasing capacity: Supercharging: Supercharged air in matte flotation or for that matter the use of the normal amount of air drawn in by the impeller would in all probability cause such an aeration in the cell as to destroy the buoyant effect given to the coal particles by the excessive amount of kerosine used. In other words, air creates an agitation zone throughout the cell, creating a boiling and thereby giving a lower recovery in the cell. It would be interesting to know whether the 7 pct increase in recovery was with no air being admitted to the stand pipe. Changing Impeller Speed: The speed of a receded disc impeller for a No. 30 cell as recommended by the Denver Equipment Co. is, I believe, approximately 250 rpm. At this speed and using supercharged air in excess of 8-oz pressure, we have observed a boiling action in the cells. In our flotation we endeavor to obtain some degree of froth flotation using pine oil as a frother. The boiling action as caused by increasing the amount of air added to the cells is detrimental to recovery in froth flotation. It is our belief that to obtain increased recovery from a cell in froth flotation, additional air must be introduced but at the same time this air must be dispersed throughout the pulp in the form of small bubbles and this can only be done by increasing the speed of the impeller. Therefore, if Mr. Schiffman decreased the speed of the No. 30 impellers and at the same time continued to use supercharged air, the boiling action may have been increased because larger bubbles developed. The lower recovery as reported could be due to this factor. Decreasing the impeller speed will definitely decrease the power consumed but may have other disadvantages. First, we believe it will permit "sanding" in the cell and this in our opinion will increase the wear on the impeller and diffuser, especially so, if there is pyrite and/or sand present in the feed. "Sanding" in the cell when air is used, as in froth flotation, will effect the dispersion of this air and cause boiling.

Jan 1, 1951

By C. R. King

Most of the acid volcanic glasses such as obsidian, perlite, pitchstone, pumice, and pumicite (volcanic ash) are susceptible to some expansion if suddenly subjected to a suitably high temperature in a properly designed furnace, and subsequently suddenly cooled. Expansion results from the action of chemically combined or dissolved water expanding as a vapor within the softened heated rock particles. This expansion forms countless minute bubbles within the pasty mass of the natural glass particles. If the particles are cooled before these bubbles can escape, the resulting products are cellular, more or less spherulitized glass froths or hollow glass spheres of many types. Chemically, they are essentially aluminum silicates containing about 70 to 75 pct silica, 10 to 16 pct alumina, and 2 to 7 pct sodium plus potassium oxides. They are relatively resistant to attack by acids or alkalies, are resistant to heat up to over 1000°F, and are completely inert to insect or fungus attack.

Jan 1, 1949

By Harlowe Hardinge, R. C. Ferguson

Laboratory and plant data covering 12 different operations show that lower than "standard" ball mill speeds increase grinding efficiency. In the case of high pulp-level mills, the gain is so great that the increase in capital cost of the larger lower speed mill will pay for itself in less than a year's time.

Jan 1, 1950

By Kenneth S. Ritchie

THE discovery well of the world's -deepest oil producing structure, University 1-B of Group No. One Oil Corporation, in the Big Lake oil field, Reagan County, Texas, has had a remarkable record. The well is outstanding for the following reasons: (1) It is the world's pioneer well to produce. oil in commercial quantities from a structure 8500 ft. below the earth's . surface; (2) this well was the only. producer from the 8500-ft. pay for a period of 17 months and 24 days; (3) the flow of the discovery well has been free from-the customary changes at the casinghead, with the exception of putting on a back-pressure of 185 lb.; and, (4) the well's daily production of oil and gas increased rather steadily for 17 months and 18 days from an initial of 40 bbl. per day to a maximum of 2926 bbl. per day, and then six months later, after a period of decline and self-readjustment to subsurface changes caused by six more deep producers, the well set its real record for one day's production of oil at 2950 bbl

Jan 1, 1931

By Oscar A. Glaeser

MINE VENTILATION is an important factor in mine maintenance as well as having direct bearing on labor efficiency. Effective ventilation systems are costly, especially those for the deeper mines, but with intelligent direction the worth of a system is usually greater than its cost. In most mines using mechanical ventilation, and practically all deep mines, it has been found beneficial to equipment, timber, and the ground, to run the fan or fans continuously even though production has been curtailed or entirely suspended. Therefore, economies in ventilation may be overlooked when general cost reductions are necessary. The operating costs of a well-designed ventilation system should be capable of reduction during periods of curtailed or suspended operations. A mine that is ventilated by splits, or that can be sectionized, can reduce its fan-power costs considerably, and provisional divisions can sometimes be made in other mines, in which the air is ordinarily coursed through all the workings, without harmful effects.

Jan 1, 1932

By AIME AIME

ON the headwaters of the Hudson Riser, in a sparsely populated area of the north woods at Tahawus, N. Y., thirty miles from the nearest railroad, is the Maclntyre property of National Lead Co. Operations involve the mining and processing of titaniferous iron ore to produce ilmenite concentrate, and magnetite concentrate containing vanadium, for use in the production of iron, titanium, and vanadium in the war program. Accordingly, Maclntyre at present is classed as a war plant. More than 3000 long tons of ore is ruined daily by opencut methods and treated in an ore concentrating plant.

Jan 1, 1943

By A. J. Opinsky

ThE superior performance of nonsag tungsten wire in lamps has been ascribed to the large-grained micro-structure that can be developed in it. The orientations of these large grains have been studied several times; most published data1-' appear to be similar to those plotted in Fig. 1. These new data were obtained by X-ray back-reflection Laue technique from all of the large grains occurring in thirteen different wires that had been heated at the lowest possible temperature for the formation of large grains. Here the wire axis is plotted in terms of the principal directions of the cube. Rosi decided that the preferred orientation of the large crystals could be described by a single ideal orientation, (531), being parallel to the wire axis.' Rieck2,3 and Mannerkoski' have essentially confirmed this finding. Opinsky, Orehotsky, and Seigle argued that the data suggest that (211) is parallel to the wire axis instead of a single ideal orientation.5 This {211} contains the (531) ideal orientation and would appear to be a more general case. Ahlborn and Wassermann report that their orientation data stretch from ( 110) through (531) to (311) 8 This is part of the locus of (211). All these investigators have determined the orientations of the large grains by back-reflection Laue techniques. They have all obtained essentially similar results. On the other hand, Swalin and Geisler, who obtained their data by neutron diffraction, indicated that the preferred orientation of the large grains in doped wire is (110) .7 These findings cannot presently be reconciled with the pole density data described in the previous paragraph. Rosi1 and Rieck2 have advanced arguments about how their orientations could occur. Nevertheless, the crystallographic link between the (110) (cold-worked) fiber texture and the preferred orientation of the large grains has remained missing. This link can be provided through the concept of coincidence-type boundaries. Such boundaries separate two grains that have a certain number of common lattice sites. Coincidence relationships that result from rotations about low index directions are given by Brandon et a1 .' What is desired is a calculation of those orientations that bear a coincidence relationship with the (110) fibers of the cold-worked matrix. This situation arises in the following fashion. Heating the tungsten wire for a combination of time and temperature falling short of the formation of the nonsag structure yields a structure that is still fibrous in nature and the preferred orientation remains (110). During grain growth, the growing grain is in contact with these fibers. It is hence possible that the entire process may begin by the passage of a coincidence boundary into a (110) fiber. The calculations were carried out analytically and checked graphically. Following Brandon et a1.,8 coincidence relationships from 1 in 5 to 1 in 19 have been considered. The results of the calculations are given in Fig. 2. Of the coincidences examined, some of those occurring upon rotation about ( 110) come closest to the experimental points in Fig. 1. Nineteen of the twenty-three data points in Fig. 1 can be attributed to the ideal orientations A, B, C, and D in Fig. 2. As determined analytically, three crystals lie within 4 deg of point A, four lie within 21/2 deg of point B, eleven lie within 5 deg of point C, and one lies within 1 deg of point D-a total of nineteen. The off-lying points are near the |110| point of the triangle.

Jan 1, 1968

By C. A. LINDBERG

Several new methods have been developed on the Iron Range to remove the material adhering to truck bodies in freezing weather. A machine known as a Gradall, incorporating the features of digging both above and below the horizontal, digging angle of blade control, full revolving, travel almost anywhere, and operated by one man, has proven successful in trials at body cleaning. Several of these units are in use with great saving in box-cleaning costs and improvements in efficiency of the truck operation with full capacity boxes. In addition to their winter use, the same machines have been used for ditching and excavating in the summer with great saving. The latest method of combating this freezing problem is to carry the exhaust from the engine through the body, making use of the tremendous heat that is now being wasted. To do this, the present wood sandwich which is used between the bottom of the box and the wear plate is removed and replaced with angles or channels run lengthwise of the box and spaced to permit gases to flow between or through them and also provide a good sup- port for the wear plate. The channels or angles are cut a little short on each end to form a cross passage that permits the gases to flow through the area. In the front end, openings are made in the wear plate and connect to a manifold created by welding a plate across the whole front of the box, spaced from the original end by the original vertical reinforcing angles at that point. The body being described is for a Euclid truck which is the only truck that has been adapted to this body-heating idea to date. At the rear of the truck, the holes from the cross passage are made in the bottom plate of the body and lead into a triangular-shaped body cross member under the scoop end of the truck.

Jan 1, 1949

By David E. Hyatt

The chemical attributes of cyanides have long been exploited in ore pro- cessing schemes for the recovery of copper, molybdenum, gold, silver, and other metal values. Blast furnacing operations are significant unintentional producers of cyanides which find their way into process waters. Many of the more than 20,000 electroplating facilities in the United States utilize cyanide plating baths and generate cyanide containing wastes. As social, political, and economic pressures for water quality attainment, maintenance, and preservation grow, the requirements for the development of treatment technology to control cyanide levels in wastewater become increasingly apparent. Just as the chemistry of the cyanide ion 1s an integral part of its industrial applicability, so must this chemistry be a fundamental part of any decomposition or removal technology used to control its level in effluent or recycled waters. The complexity of this chemistry is substantial and it cannot be considered in a superficial or cursory manner if control system design is to be both efficient and reliable.

Jan 1, 1975

By David R. Maneval, H. B. Charmbury

At the turn of the century, iron and coal were the keys to industrial prosperity. At that time, Pennsylvania was the leading mineral producer in the Country, producing 200,000,000 tons of coal in a typical post-World War I year. Close to 90% of the Nation's energy was generated by coal. Today, coal accounts for but 22% of the energy generated, leading to a drastic reduction in Pennsylvania coal output. In contrast with the post-World War I days, 1964 figures showed a drop in production to 93,846,480 net tons. This huge decrease has created a serious economic problem in a state so much dependent on the coal industry. Along with the reduction in coal production, employment has dropped considerably through these years (the number of miners alone has gone from 280,011 to 43,149), thus causing a heavy burden of supporting the unemployed on the taxpayers. As far back as 1939, coal operators and economists saw the problems on the horizon and the need for improvement. Realizing that research was a way to improve and stabilize the industry they demanded legislative action. The Legislature reciprocated with a small grant to The Pennsylvania State University with the provision that each State research dollar be backed with one from the industry. This initial grant laid the foundation for the further growth in coal research.

Jan 3, 1966