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By Dell P. Williams, Howard G. Nelson

The tensile behavior of magnesium single crystals at a temperature of 26º ± 2ºC was investigated at varying pressure levels from 760 to 8 X 10-8 tow. For crystals deformed at a constant linear strain rate of 0.061 min-1. there was no apparent effect of the vacuum environment down to 10-8 torr. However, from a vacuum of 10-5 torr down to the lowest pressure attained (8 x 10-8 tor,), the effect of the vacuum environment was to increase the strain at the end of the first linear (or easy-glide) stage and to decrease the slope of this stage; the magnitude of this effect was found to be dependent on pressure. The slope of the second linear stage was also decreased at the lower pressure levels; however, this effect appears to be caused primarity by the vacuum effect on the first linear stage. The magnitude of the vacuum-environmrnt effect was also found to be dependent upon strain rate. The reduction in flow stress at 5 x 10-8 torr, as compared to the stress in air, was obserced to be about 10 pct for a strain rate of 0.0250 min-' and 70 pct for a strain rate of 0.67 min-1. No systematic effect of pressure on the critical resolvled shear stress was observed. The data interpreted in terms of a modified form of Mott's work-hardening mechanism for hexagonal metals. It has long been known that surface conditions influence the mechanical behavior of materials. Roscoe 1 demonstrated the importance of surface conditions on mechanical behavior by testing cadmium crystals with oxide layers. He found that the "apparent" critical resolved shear stress for cadmium was increased approximately 2.5 times by the presence of an oxide layer 1000 atoms thick. The magnitude of this effect was dependent on film thickness with crystals having films less than 20 atoms thick still showing a definite increase. This observed strengthening could not be attributed to any strength of the oxide film because of 1) the thinness of the films and 2) an observed increase in the flow stress as deformation proceeded. Harper and cottrel12 obtained similar results on zinc crystals which had been etched and steamed to give artificially thick oxide films. However, in the course of this study, they also carefully examined the very early stages of plastic flow for zinc crystals which in one case had been electrolytically polished and in the other had been lightly etched to produce a thin film. They then found that the critical resolved shear stress for both surface treatments of the crystals was actually identical but that the etched crystal exhibited a much more rapid initial hardening rate. This had not been noted previously. This result indicated that, in fact, the film caused an increase in the stress for continuation of slip, rather than for the initiation of slip. Lipsett and King3 investigated the effect of evaporated gold films on the plastic behavior of cadmium single crystals. For large angles (=75 deg) between the specimen axis and the normal to the slip plane, they found that the stress-strain curve of the coated specimen always lies above that for a clean specimen. The shear strain at the end of the first linear stage was greater in clean specimens than in coated specimens and the slope of the second linear stage was

Jan 1, 1965

By E. T. Dumble

Introduction..........914 I. Topography,........915 The Nueces Basin........915 The Coastal Slope...........918 Streams..........919 II. Geology..........921 Eocene..........923 Basal Beds .......923 Lignitic Stage........923 Atascosa Sections......924 International and Great Northern Sections .. . 928 Leona Sections.......929 Nueces Sections....929 Rio Grande Sections.....930 Lower Claiborne Stage......932 Marine Beds ........933 Atascosa Sections....... 933 International and Great Northern Sections .. . 934 Frio County Sections,.....935 Rio Grande Sections.....936 Yegua Clays........938 Atascosa Sections......938 Tilden Sections.......941 International and Great Northern Sections .. . 942 Rio Grande Sections.....942 Fayette Sands........945 Atascosa Sections......946 Tilden Sections......948 Rio Grande Sections.....950 Frio Clays........953 Atascosa-Frio Sections.....953 Tilden-San Diego Sections....955 Rio Grande Sections......955 Neocene ....966 Oakville Beds.......957 Lapara Beds,....... 987 Nueces Sections......958 Bartlett's Ford Sections.....959 Fort Merrill Section......963 Lapara Sections,.....964 Tilden-San Diego Section.....967 Lee Tiendas.......969

Jan 1, 1903

EXECUTIVE COMMITTEES OF LOCAL SECTIONS New York L. W. FRANCIS, Chairman, WILLARD S. MORSE, Vice-Chairman. THOMAS -T. READ, Secretary, Woolworth Bldg., New York: N. Y. P. A. MOSMAN, Treasurer. LOUIS D: HUNTOON. Boston HENRY L. SMYTH, Chairman. ALFRED C. LANE, Vice-Chairman. AUGUSTUS H. EUSTIS, Secretary-Treasurer, 131 State St., Boston, Mass. TIMOTHY W. SPRAGUE, HENRY A. WENTWORTH. Columbia F. A. THOMSON, Chairman. GEORGE W. RODDEWIG, Vice-Chairman. LYNDON K. ARMSTRONG, Secretary-Treasurer, P. O. Drawer 2154, Spokane, Wash. R. S. McCAFFERY, S. H. RICHARDSON.

Jan 10, 1914

By J. Chipman, T. P. Floridis

The equilibrium of gaseous H2O-H2, mixtures with liquid iron is used to establish the activity coefficient of dissolved oxygen as log f o = — 0.20 [%O]. Discrepancies in earlier work are explained or eliminated. Additions of cobalt, molybdenum, tungsten, and platinum increase the activity coefficient of oxygen whereas copper and gold decrease it. THE importance of dissolved oxygen as a refining agent in liquid steel has led to a number of studies of its thermodynamic properties. It is the purpose of this paper to examine the effects of a number of alloying elements on the activity of oxygen in the steel bath. As a preliminary to the study of the effects of alloying elements, it seemed desirable to examine certain minor discrepancies in the published data on the properties of oxygen in simple iron-oxygen solutions. The activity and free energy of oxygen in liquid iron were studied by chipman1 in 1933 by means of the reaction h2(g)+-o = H2O (g);K; = PH2O/PH2[% O] [1] The data were in fairly good agreement with calculations from results on the similar reaction CO (g) + O- = CO2 (g); K2 =P CO2/P CO [% O] [2] which had been obtained by Vacher and Hamilton2 as an incidental part of their study of the reaction of carbon with oxygen dissolved in the melt. It was found that the equilibrium ratio k1 was not a true constant but varied with the oxygen concentration in the manner shown in Fig. 1, which is copied from the original paper. This early observation has been refuted in subsequent work but is confirmed in the present paper, and an explanation of the discrepancy can now be presented. In Fig. 1, the two points on the extreme right were disregarded in drawing the

Jan 1, 1959

By B. M. Burchfiel

CALIFORNIA possesses such an abundance of ceramic materials other than clays, that she is quite independent of other states and foreign countries so far as these materials are concerned. Certain users import some feldspar, silica, and allied minerals, but they do so from choice and not necessity. Production is largely for home consumption, so the total volume of ceramic materials produced is comparatively small. Many small deposits of the materials here under discussion are worked by individuals, and their output sold to individual grinding companies or users. The data given here shall be confined to the larger deposits and developments because they give a truer picture of typical deposits, operations, and materials.

Jan 1, 1936

By T. D. Thomas

In this paper, major attention is given to misfires in mines where electric multiple shot-firing is the system used. Misfires are sometimes caused by one action or condition and at other times by a combination of two or more. They may be divided into two classes: (1) those caused by workers in the mines, (2) mechanical or manufacturer's causes. The second cause will be discussed first. Misfires Caused by Faulty Detonators The important part of an electric blasting cap, to the user where multiple shot-firing is done, as in the steep-pitch, thiek-vein, anthracite mines, is the bridge wire. In single shot-firing this factor is not apparent, but in mines where multiple firing is done any variation in the resistance of the bridge wire, where full or even rated battery capacity is required, will most likely cause a misfire. The reason for this is obvious. If the resistance in the bridge wires is not the same, some of the detonators will fire because of their greater comparative resistance. Variance in resistance of bridge wires is caused by a slight difference in the diameter of the bridge wire, also by a difference in the composition of the bridge wires. Again, where the bridge wires have become rusted, there will be a variance in resistance. About the year 1922, one of the large coal companies was greatly alarmed by the number of serious and fatal accidents caused by misfires. The general manager issued an order that these accidents must be greatly reduced, and if possible, entirely prevented. The officials at the mines had to determine the various causes of misfires and have them corrected. The rock contractors who use large quantities of 60 to 80 per cent. explosives and do all firing electrically were thoroughly instructed as to the proper methods of doing their work, and closer supervision was given to their work. The manufacturer's representatives stressed the importance of the use of galvanometers; accordingly these were purchased and used. Larger firing lines were installed under the supervision of a demonstrator of the company manufacturing the caps and explosives. However, misfires again occurred and it was evident that the source of the trouble was not wholly

Jan 1, 1930

By John V. Beall

Let's start at the beginning, Mr. Turner. Where and when were you born? In Lansing, Mich., on July 31, 1880. And what was your education? I went to the University of Michigan, where I got an A.B. degree in 1902; then to the Michigan College of Mines at Houghton, graduating from there in 1904 with a B.S. and an E.M. What was your first job in the mining industry, Mr. Turner, and what were you paid? In the summer of 1902, 1 was a field assistant for the U. S. Geological Survey in southwestern Idaho and southeastern Oregon, working under Israel C. Russell, professor of geology at the University of Michigan, who incidentally, had just returned from an expedition to study the effects of the eruption of Mt. Pelee, on Martinique. I was paid $60 a month and found; in addition to doing geologic and hydrographic work, I cooked many of the meals for a party of four, and wrangled four horses. I slept for four months under the stars, without a tent.

Jan 1, 1949

By G. E. Warner

This paper presents a review and analysis of a highly stratified Burbank sand waterflooding project in Osage County, Okla. Permeability values in this reservoir range from less than 0.1 md to nearly 3 darcys, and 90 percent of the permeability capacity is contained in approximately 26 percent of the reservoir volume. To date, the project has recovered 103 bbl/flood-acre-ft since waterflood initiation, which represents 50 percent of the total preflood cumulative and 12 percent of the original stock-tank oil in place (OSTOIP). The outstanding feature of this project has been the economical recovery of a sizable quantity of oil at water-oil ratios higher than those normally considered prohibitive. Nearly 70 percent of the recovery to date has been achieved at water-cut values greater than 95 percent. An ultimate waterflood recovery of 138 bbl/flood-acre-ft, or 67 percent of the preflood recovery and 16 percent of the OSTOIP, is predicted. The ultimate primary and secondary recovery will be 302 bbl/acre-ft and approximutely 40 percent of the OSTOIP. The actual performance is compared with the predicted performance by both the Stiles and the Dykstra-Parsons methods, and applicabiliry of these methods to this particular reservoir is evaluated. The performance of this project indicafes highly stratified reservoirs can be successfully and economically waterflooded when either reservoir or economic conditions preclude the use of mechanical and chemical means of mdbility control. Introduction The concept of the stratified reservoir has been used by reservoir engineers for many years to describe the vertical variations in permeability within a reservoir. Numerous techniques have been advanced to predict the expected waterflood performance of the stratified reservoir, and in most cases they prove reasonably accurate. The advisability of undertaking a prospective waterflooding project is determined, based on these predictions. This paper presents a review of a waterflood project in a highly stratified reservoir that normally would be considered a marginal prospect, at best, when evaluated with any prediction technique properly adjusted for reservoir conditions. This kind of project can be successful if the predictions are used to design a waterflooding system capable of economically recovering an oil cut of 1 to 2 percent. Experience gained in the early stages of the project's development was profitably applied in the later development of the entire reservoir and could prove beneficial to other projects with similar reservoir stratification or fracture characteristics. The East Burbank pool waterflooding operations have been developed in three separate stages, each of which has been a separate project: Mid-Burbank Unit, Flood A, and Stanley Waterflood. When referred to collectively, these projects will be called the Composite Project. The Skelly Oil Co.'s Barber lease — the only portion of the pool not included in the three projects — is operated as a separate facility with a cooperative injection-well agreement. It contains less than 80 productive acres and would not significantly affect the over-all performance picture.

Jan 1, 1969

By J. A. Grimes, Paul Billingsley

A. Introduction. 1. Association of Ores and Igneous Rocks. 2. Identity of Granite Rocks. B. General Geology. 1. Geologic Events of the Igneous Cycle. 2. Association of Igneous Intrusions with Tectonic Forces. C. Igneous Rocks. 1. Andesite Period. 2. Granite Period. (a) Diorite. (b) Quartz-Monzonite. (c) Aplite. (d) Quartz-Porphyry. (c) Quartz-Veins. 3. Rhyolite Period. 4. Comparative Analyses. D. Classification of Deposits. 1. Genetic Classification. 2. Parallelism Between Igneous Stages and Stages of Ore Deposition. Part 2.—The Ore Deposits Andesite Period. A. Andesite Phase. 1. Disseminations—Baggs Creek. 2. Contact Deposits—Iron Mines of Ekhorn Mountains. 3. Fissure Veins—Emery District. (a) Fissure Veins in Andesite Walls. (b) Mineralization Along Bedding of Flows. (c) Mineralization of Amygdaloidal Lavas. (d) Mineralization of Breccia. 4. Summary.

Jan 1, 1918

By Oswald J. Heinrich

(Read at the Philadelphia Meeting, February, 1878.) DURING the last twenty years much has been done to investigate and define the Mesozoic formation of the United States along the Atlantic States, as well as in the Territories. The investigations of Professors Hitchcock, Emmons, Hayden, H. D. Rogers, and those now in progress in connection with the geological surveys of Penn-

Jan 1, 1878

Jan 4, 1976

Photographs of Officers

Jan 1, 1923

By W. C. Ellis, E. S. Greiner, M. E. Fine

C. H. Samans and W. R. Ham (Chicago, Ill., and Dix-field, Maine, respectively)-—For several years we have been studying transitions of this basic type in metals, alloys, glasses, etc. Usually, however, they are not so clearly marked as those which the authors have found, and hence are much more difficult to determine accurately. Since our studies indicate that most of them occur virtually unchanged (as far as temperature is concerned) regardless of the form in which the element appears, we believe that they are a characteristic of the atom. Specifically, we believe that there is an additional rotational degree of freedom possessed by the nucleus which has not been considered heretofore. This nuclear rotation is made up of several components, each related to the several quantum shells of electrons. In chromium there are four of these shells and hence four separate series of characteristic transition temperatures. The lowest temperature at which any transition occurs, based on the present state of our computations, is 125°K, 4° higher than the authors' value of 121°K. A convergence of this series, we believe, shows up at the higher temperature of 2085 °K, surprisingly close to the transformation temperature of 2103°K recently announced by N. J. Grant of M.I.T. for a body-centered to face-centered transformation in chromium. Likewise, our computations indicate a temperature of 311°K for the second transition temperature, reported by the authors as 310 °K. A convergence of this series, we believe, shows up at a higher temperature as the melting point at 2163°K. Although our work on these series must, in a sense, still be regarded as empirical, since we do not understand fully as yet just what the series mean, it is based on a reasonably firm picture. The individual constants, from which the various series are computed for each element, comes directly from the X-ray K absorption limit. Furthermore, the same basic method has accounted for transformation and melting temperatures in about 50 of the chemical elements, which is all we have tried thus far. In many cases the only known transformation is the melting point, but in others the occurrence of transformations or other transitions, equally as well marked as those of the authors, has been pointed out by others. These observations have assisted us greatly. Consequently we were very pleased to see the authors' excellent work in finding these two transitions in chromium. With these confirming data, our picture of this element is clarified considerably, so we expect that at least some of our work can be published in the near future. R. C. Ruder (E. I. du Pont de Nemours & Cu., Wilmington, Del.)—The authors' interpretation of these transitions in terms of 3d to 4s electronic structure transitions is most interesting. It would be interesting to have additional experimental evidence of such transitions from the temperature dependence of the Hall coefficient in the neighborhood of the property changes discussed in this paper. Simple theory15 suggests the Hall coefficient as a measure of the free electron (or s electron) concentration per unit volume. It has been shown that for paramagnetic'" and ferromagnetic1? metals the simple theory is in fact too simple. However, the existence of a discontinuity in the Hall coefficient would provide information which should aid both in our understanding of these transitions and the significance of the Hall coefficient in these metals. It was rather surprising that no significant paramagnetic effects were observed. In this connection the recent work of McGuire and Kriessman18 is cited. They measured the magnetic susceptibility of chromium from 20" to 1460 °C. They also observed no large change in the susceptibility although there might be a change in slope in the vicinity of the 40 °C transition. The existence of these 3d to 4s electronic transitions has been discussed in connection with the paramagnetic susceptibility behavior of nickel and nickel alloys.'"-" Assuming a correspondence principle between classical and quantum mechanical paramagnetic theory and using classical theory to calculate the effective Bohr magneton number from the Curie constant for substances obeying the Curie-Weiss law," it is found that the effective magneton number is a function of temperature. The process of calculation involves the inverse of the differential of the 1/x4 vs. temperature curve so that good and numerous data are necessary to obtain significant results. The data of Fallot23 show a discontinuous increase of about 12 pct in the effective magneton number between 850" and 900 oC, followed by a continuous increase up to the melting point. The data of Sucksmith and Pearce24 show a possible 8 pct increase. The older data of Terry25 and Weiss and Foex26 show a continuous increase. It is possible that small amounts of impurity atoms change these electronic transitions significantly. Fallot's23 data on a nickel alloy with 4.5 atomic pct Fe indicate that the discontinuity occurs around 1300 °C. Systematic investigation of the transition metals for transitions of this nature should provide information which would be very valuable for our understanding of these metals. The absence of antiferromagnetic structures in chromium has been shown by Shull27 using neutron diffraction techniques. M. E. Fine, E. S. Greiner, and W. C. Ellis (authors' reply)—The remarks by Drs. Samans and Ham are certainly very interesting, in particular those pertaining to the close agreement between the theoretically calculated values for transition temperatures in chromium and the experimental values reported by a number of investigators. This is a remarkable achievement and we shall look forward to a more detailed presentation of the method followed in their calculations. We do not believe that the transition in pure chromium near 40 °C remains temperature invariant with alloying, as was reported by Samans and Ham for a number of the substances that they studied. We have not done any work with alloys but base our belief on the results of earlier studies in which less pure chromium was included and considerably lower transition temperatures were observed. The transition tempera-

Jan 1, 1952

By J. Richard Kyle

Lead-zinc ore bodies in the upper part of the Pine Point carbonate barrier complex are localized in paled-solution structures that developed as the result of post-middle Givetian subaerial exposure. Detritus-filled dolines host prismatic ore bodies, and macropores and stratabound permeable zones contain tabular ore bodies. Sulfides are concentrated in these transgressive paleosolution structures that acted as natural bypasses between aquifers and loci for mixing of fluids of different character. Complex ore textures indicate rapid early sulfide precipitation followed by slower sulfide growth. Evidence for both sulfide-carbonate equilibrium and disequilibrium conditions suggest fluctuations in ore fluid composition, perhaps related to periodic supply of reduced sulfur. District and ore body metal distribution pattern may reflect the nature and movement of mineralizing fluids.

Jan 1, 1981

By L. R. Smith

BUTANE OPERATED drilling rigs are a recent innovation in the petroleum industry, so extensive data on their operation are not available. However, experience indicates that, within limitations, as much can he accomplished with butane as with steam, at a decided reduction .in expense of installation and cost of operation. Commercial butane is a liquid motor fuel similar to gasoline, but much more volatile, so that it has to be stored under pressure. At 10° F. it is liquid at atmospheric pressure, but at 100° it has a pressure of 70 lb. or more. As soon as the pressure is reduced, it turns to vapor and in that state is far more easily mixed with the air necessary for combustion. Butane occurs as a by-product in the absorption process of natural gasoline extraction from casing-head gas. The product has been used to some extent 10 raise the octane value of gasoline. However, because of its volatile nature, such admixture is stable only to a limited degree. Attempts also have been made to introduce the product in a gaseous form into oil- hearing formations in repressuring work. It has, however, until recently, for the most part been wasted.

Jan 1, 1937

By H. I. Aaronson, H. A. Domian, A. D. Brailsford

A current study of the growth kinetics of k (hcp) plates in a Cu-Si (fcc)' has generated a requirement for data 02 the chemical interdiffusion coefficient in a (termed D,) as a function of temperature at the composition of the a/a + k pJase boundary. Rhines and Mehl 2 have determined D, as a function of composition at lower silicon contents by making Matano analyses of concentration-penetration curves. However, the accelerating increase in B, which they demonstrated as the phase boundary composition is approached at constant temperature and the rapidly diminishing accuracy of this analysis as the limiting compositions of a diffusion couple are approached (the silicon-rich component of their couples contained appreciably less silicon than is permitted by the solubility limit) indicate that the required information cannot be safely obtained by extrapolation of their data. Although the quite different method employed in this study is not exact, it will be shown that the approximations made are not serious ones, particularly from the viewpoint of the prgcipal application anticipated for these data. D, was determined from the migration kinetics of the a :k boundaries formed in sandwich-type diffusion couples produced by welding a block of high-purity copper to opposite sides of a cube (* in. on edge) of homogenized high-purity Cu-5.82 wt pct Si alloy. The alloy is pure k in the temperature range employed. The surfaces of the couple components which were normal to the diffusion direction were machined accurately flat and parallel, lightly polished, and carefully cleaned. Welding was then accomplished by means of the vacuum-encapsulated pressure jig technique previously employed.3 Welding was always conducted at the intended diffusion temperature; thus the welding anneal also served as the first diffusion anneal. Subsequent diffusion anneals were performed in evacuated Vycor capsules. Following the welding anneal, one of the surfaces parallel to the diffusion direction was machined, ground, and polished flat; additional material was removed from this surface after each diffusion anneal in order to avoid any effects of composition changes. After etching,4 the average distance between a : k boundaries was measured by means of a traveling microscope with an accuracy (per measurement) of better than 1 p. Satisfactory results were obtained at four temperatures in the range 775° to 655°C; attempts to obtain data at two lower temperatures were unsuccessful, evidently as the result of the interference of surface contamination during the welding process.

Jan 1, 1969

By R. A. Perry

DURING 1943, supplies of lead, like those of most base metals, moved from a position of scarcity to one of ample supply for all possible war requirements. The principal worry in the market, as 1944 began, was that surplus stocks might increase too rapidly to maintain price stability. The problem of postwar stockpiling had definitely entered the picture. The end of the year finds the lead industry having met all use demands, but not without depleting stocks to a critical low in spite of heavy importations. The principal reason for this dangerously reduced stock position is lack of adequate man power, which, without question, has become the lead industry's number one problem. This condition became obvious about the middle of the year, after Selective Service placed in effect orders that no deferments would be given employees under 26 years of age, and to a complacent attitude toward the industry assumed by the War Manpower Commission. It has become progressively worse since then. The WPB continued its policy, started during 1943, of easing restrictions on materials to be used for maintenance, repairs, and operating supplies. The policy of premium payments established by the Metals Reserve Co. was continued and, in spite of expressions to the contrary, has proved quite satisfactory. In short, the Government continued its program of stimulating the lead industry in practically all

Jan 1, 1945

By Samuel S. Wyer

THE following abbreviations have been used in, the text: Cassier's, Cassier's Magazine. Eng. Lond., The Engineer (London). Eng. Mag., Engineering Magazine. Eng. and Min. Jour., Engineering and Mining Journal. Eng. News, Engineering News. Eng. Rec., Engineering Record. Engng., Engineering. Engr., The Engineer (Chicago). J. I. and S. I., Journal of the Iron and Steel Institute. Jour. F. I., Journal of the Franklin Institute. Jour. Assn. Eng. Soc., Journal of the Association of Engineering Societies. Mar. Eng., Marine Engineering. . Mem, Soc. Ing. Civ., France, Memoires de la Society des Ingenieurs Civils, France. Prac. Eng., Practical Engineer. Proc. Digs. Soc. of W. Pa., Proceedings of the Engineers' Society of Western Pennsylvania. Proc. I. C. E., Proceedings of the Institute of Civil Engineers. Proc. I. 1M. E., Proceedings Institution of Mechanical Engineers. Trans. A. I. M. E., Transactions of the American Institute Mining Engineers. Sci. Am., Scientific American. Sci. Am. Sup., Scientific American Supplement. Zcitschr. d. V. D. Ing., Zeitschrift des Vereines Dentscher Ingcnieure.

Mar 1, 1905

By David W. Wisecarver, James F. Reynolds

INTRODUCTION The Department of Energy is cooperating with Snowmass Coal Company near Carbondale, Colorado to introduce the longwall mining method in moderate to steeply pitching coal seams in the United States. This venture is part of a coal mining research program directed toward development, trial, and analysis of mining technique8 to improve production and recovery in the more difficult mining conditions such as thick, multiple, and steeply pitchly seams found in the Western U.S. The project at Snowmass is the first attempt in the United States to operate a longwall in a steep coal seam. Plans are to mine three adjacent, successively downslope panels in the eight foot thick seam which varies in pitch from 27 to 33 degrees. During this work, researchers and mine engineers are expected to obtain answers to many engineering questions relative to panel design and development, selection of face equipment and beet operating techniques and procedures. They are also committed to obtaining hard data on costs, recovery, production, safety, and behavior of underground mine structure as the three panels are mined. This information is essential to future mine engineering and profitable mining of pitching Western coal reserves. Development of the first trial panel was begun in 1979 and completed in June 1981. The longwall mining equipment was then installed in the starting room and retreat mining begun on August 11, 1981. Project duration is expected to be about five years during which over tm million tons of coal will be produced. TRAINING The longwall mining method is new to Snowmass. For years the mine produced coal by room and pillar methods using conventional techniques to mine upslope rooms and Alpine F6A miners to cut entries and rooms on strike. Miners were experienced in room and - pillar mining from other mines. News of the longwall demonstration was received enthusiastically by Snowmass miners. Employee interest in the project was 100%. However, there was minimal longwall experience on site. In fact, most of the work force had not even seen a longwall. Mine and company management were well aware of the immediate need to develop trained longwall face mining crews and maintenance people qualified to work on longwall equipment and also expertise in longwall planning, equipment selection, power distribution design, ventilation requirements and panel development. The first approach to answer this huge deficiency in longwall mining experience was obviously training. Hence a training program directed toward those mining specifics most urgent to the beginning mining phases was initiated in mid-1980. Classroom lectures and hands on training, using instructors from equipment suppliers and available company longwall expertise, was conducted in longwall subjects to include face mining procedures, panel development, operation of equipment, equipment assembly and maintenance, electrical circuitry and controls, ventilation, move of longwall equipment, and safety procedures. At the same time, responsible engineers and foremen were sent on a tour of European pitching longwalls to see first hand how other mines working under similar seam conditions conducted their operations. Development techniques, types of equipment, methods for transport of men and materials, and ground control techniques were discussed with engineers, foremen and officials at each mine. This look at European longwall mining operations gave Snowmass good insight into the unique problems associated with longwall mining on 30' pitch. Mining considerations such as face conveyor/ support system slippage downslope, panel development, maintenance, safety considerations, manpower requirements, and haulage methods were covered with European experts

Jan 1, 1982

By AIME AIME

LEADING off the Thursday morning session on Non-metallics was C. E. Heinrichs' paper, "Phosphate Flotation, Its Place in the Technology and Economics of the Phosphate Industry." Mr. Heinrichs also presented a closely related paper, "Milling Methods and Costs at the No. 2 Concentrator of the Phosphate Recovery Corporation," by H. S. Martin. The first of the papers points out the great significance of flotation to the phosphate industry, inasmuch as flotation practically doubles the potential recovery, thereby decreasing production costs and increasing reserves materially. The second paper describes three such plants, two of which are in Florida, the third being at Wales, Tenn. Operating characteristics and costs are reviewed. Answering inquiries from the floor, Mr. Heinrichs said that the adoption of a new parallel-shell dryer, from 60 to 80 ft. long, instead of the old single-shell countercurrent dryer, had increased the unit drying capacity over 300 per cent and had reduced the drying cost to less than 25c. per long ton of dried product. The initial moisture is from 15 to 18 per cent and the final about 2 per cent.

Jan 1, 1933