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By Theron Wasson

Michigan has had another record year. Its production has been maintained by the development of fields discovered in 1938. Two minor fields were listed as discoveries in 1939. These are in the southwestern part of the state, where the greatest drilling activity took place. During the year 1465 tests were completed, of which 828 were oil wells, 56 gas wells and 581 dry holes. The four southwestern counties—Allegan, Ottawa, Kent and Van Buren—had 1077 tests drilled, while nine other southwestern counties had 70 tests, making a total of 1147 for this part of the state, 78 per cent of all drilled during the year. Michigan's production of 23,400,000 bbl. during 1939, equal to an average daily production of 64,110 bbl., exceeded 1938 by 4,655,000 bbl., thus establishing another annual record, which brought the cumulative amount for the state to a little over 125,000,000 barrels. A map showing location of Michigan oil and gas fields was published in the TRansactions in 1939 (Vol. 132, p. 353). Active Oil Fields.—The Walker field, near Grand Rapids, Kent County, had a rapid development during the year. Traverse limestone production was discovered here in September 1938, and development has been rapid during 1939. At the end of the year 5500 acres have been proved by drilling. The Traverse limestone is found in Walker field at a depth of about 1810 ft. The Temple field, Clare County, was the most active in Central Michigan. Its production is from the Monroe dolomite at a depth of 3890 ft. In this field 2500 acres have been proved by 125 producing wells. Michigan's largest producer for 1939 was drilled in the Temple field, with a rated potential of 8760 bbl. per day. The Wise field, Wise township, Isabella County, discovered in 1938, had a steady and orderly development because the operators agreed on a staggered 20-acre spacing program. So far 760 acres have been proved for production from the Dundee limestone, found at 3650 feet. Active Gas Fields.—The most active areas in which drilling was done during the past year for gas were the Freeman and Lincoln fields in Clare County, the Clayton field of Arenac County, and the Home field of

Jan 1, 1940

By F. E. Wood

Since the earliest discoveries of oil in the Rocky Mountain area the spirit of cooperation in drilling and production programs has prevailed. There has scarcely been a field which has not been developed in an orderly manner through mutual agreement between competitive operators. An appreciable saving has resulted, as many unnecessary wells have been eliminated. We have unit operation plans and agreements which were developed at an early date. Rock River, found in 1918, has been a unit operation. One of the first prorate agreements ever attempted was made in Salt Creek in 1921. Teapot, first developed in 1922, has been a unit operation; the lessee, the Government, and the lessor, one operator. South Casper Creek, found in 1918, has been developed as a unit. Rex Lake, found in 1923, is a unit operation. The list might be extended materially but it serves to indicate that the Rocky Mountain region enjoyed the fruits of unit operation at an early date. It is concluded from this unitization study in the Rocky Mountain region that there is an appreciable saving in both development and production costs as well as the elimination of waste of a natural resource. Certainly, when unit operation conserves an irreplaceable natural resource as well as capital, any legal or political impediment to its successful development will be overcome. If one company supervises the operations in one field, it appears to be a unit operation. This may not be true if the lands involved have been leased from a great number of lessors. Royalty holders create a most intense competitive operation. The Rocky Mountain region has its full quota of such diversified interests. The original study calls for consideration of two types of fields, unit and near-unit operation. This Committee has felt that if an agreement of any character has brought about a saving it is an approach to unit operation. The fields have been classified into four types: 1. Unit Operation.—Any field whereby the competitive drilling-drainage feature is or will be absent in the development and operation of the pool.

Jan 1, 1930

By Theron Wasson

Michigan has had another record year. Its production has been maintained by the development of fields discovered in 1938. Two minor fields were listed as discoveries in 1939. These are in the southwestern part of the state, where the greatest drilling activity took place. During the year 1465 tests were completed, of which 828 were oil wells, 56 gas wells and 581 dry holes. The four southwestern counties—Allegan, Ottawa, Kent and Van Buren—had 1077 tests drilled, while nine other southwestern counties had 70 tests, making a total of 1147 for this part of the state, 78 per cent of all drilled during the year. Michigan's production of 23,400,000 bbl. during 1939, equal to an average daily production of 64,110 bbl., exceeded 1938 by 4,655,000 bbl., thus establishing another annual record, which brought the cumulative amount for the state to a little over 125,000,000 barrels. A map showing location of Michigan oil and gas fields was published in the TRansactions in 1939 (Vol. 132, p. 353). Active Oil Fields.—The Walker field, near Grand Rapids, Kent County, had a rapid development during the year. Traverse limestone production was discovered here in September 1938, and development has been rapid during 1939. At the end of the year 5500 acres have been proved by drilling. The Traverse limestone is found in Walker field at a depth of about 1810 ft. The Temple field, Clare County, was the most active in Central Michigan. Its production is from the Monroe dolomite at a depth of 3890 ft. In this field 2500 acres have been proved by 125 producing wells. Michigan's largest producer for 1939 was drilled in the Temple field, with a rated potential of 8760 bbl. per day. The Wise field, Wise township, Isabella County, discovered in 1938, had a steady and orderly development because the operators agreed on a staggered 20-acre spacing program. So far 760 acres have been proved for production from the Dundee limestone, found at 3650 feet. Active Gas Fields.—The most active areas in which drilling was done during the past year for gas were the Freeman and Lincoln fields in Clare County, the Clayton field of Arenac County, and the Home field of

Jan 1, 1940

By C. Wert, P. Bunn

Determination of the solid solubility of gases in metals is usually done by one of two methods. The first is an additive method, in which measurement is made at temperature of the maximum amount of gas absorbed by an initially degassed piece of the metal. Gas additions are made until the dissolved gas first comes into equilibrium with a compound. This method is most useful at relatively high temperatures where the amount of gas absorbed is relatively large and where equilibration of the dissolved gas with the gas atmosphere can be achieved in a relatively short time. The second is a precipitation method. A supersaturated solution of the gas in the metal is held at temperature until equilibrium is established between the gas atoms in solution and a compound. The quantity of dissolved gas is then determined by some physical measurement which is sensitive only to the gas in solution. This method is generally useful in low temperatures. This paper describes measurement of solubility of nitrogen in tantalum whereby measurements at low temperatures using internal-friction methods are plotted together with existing measurements at high temperatures. The solubility is thereby known from less than 0.5 at. pet at 350°C to near 13 pet at 2300°C. Several measurements have been reported of the solubility of nitrogen in tantalum. These are collected in Fig. 1. Three single determinations by Ke,1 Andrews,2 and Brauer and zapp3 are plotted along with a series of measurements by Vaughn, Stewart and schwartz4 and Gebhardt, Seghezzi, and Fromm.5 Although not much doubt exists about the solubility being in excess of 10 at. pet above 2000°C, the solubility indicated at low temperatures depends on whose data are selected as being most reliable. The variation is enormous, being at least an order of magnitude at 500°C. Accordingly, a measurement was begun to examine this discrepancy. The method of measurement finally selected was that of internal friction. A solid solution of nitrogen in tantalum was prepared by heating a tantalum wire in a dilute at-

Jan 1, 1964

By T. Sterry Hunt

I HAVE in a previous communication called the attention of the Institute to the geognostical relations of the crystalline iron ores belonging to the Eozoic rocks of North America, at which time I noticed (1) those associated with the gneisses of the Laurentian series, (2) those of the crystalline schists of the Huronian, as seen in Northern Michigan and in many localities along the Appalachians ; (3) those of Southeastern Missouri associated with petrosilex porphyries and schistose rocks, and presumed to be nearly of the same age with those of the Huronian schists; and (4) the highly titaniferous ores of the Norian or Labradorian series from Essex County, N. Y., and from various parts of Canada. It may here be remarked that, although the presence of titanium is most marked in the Norian ores, this objectionable element is sometimes found in the schistose ores of the Huronian, and to a lesser extent in certain Laurentian magnetites. The ores of each of these geological divisions have their individual peculiarities, which serve to distinguish them to such a degree that the magnetites and specular ores of the Laurentian are as dissimilar to those of the Huronian as are the crystalline silicated rocks of the two series. As it happens that these mineralogical dissimilarities correspond to differences in composition and in adaptability to different processes of manufacture, which, in the present condition of the iron industry, are objects of special consideration to metallurgists, it will be seen that these geognostical distinctions become of great practical importance. During the past year I was desired by the Geological Commissioners of Pennsylvania to devote a few weeks to certain geological studies in the eastern part of the State, in the course of which I was enabled to make, with regard to its crystalline iron ores, some observations to which I desire to call the attention of the Institute. I may mention, in passing, that the great South Mountain belt, from the Schuylkill to the Delaware, is composed of Laurentian rocks, in which are found the characteristic ores of the series like those of the Highlands of New Jersey and New York, and of the Adiron-

Jan 1, 1876

By Henry A. Ley

Kansas ranked fourth on the list of oil-producing states during the year 1930. Progressive statistics show that total production for the year will approximate 42,729,085 bbl. When final figures are compiled for Kansas the production may exceed this estimate, and thereby threaten the all-time record of 43,253,470 bbl. in 1918. Throughout the year the cumulative volume of potential drilled-up production has been increased by new discoveries and by extensions to proven areas in the territory west of the Nemaha (granite ridge) Range. Scattered drilling and leasing operations of a constructive nature occurred, but completions declined to the lowest levels in more than 11 years. Average initial production of current completions climbed to a new all-time high of 512 bbl. to the well. Proration measures were applied to the flush pools. The resulting shut-in potential production, as of December 15, is estimated at 110,000 bbl. This estimate is a wild guess. If all wells of the state were permitted to flow wide open for a period of six months production would not exceed 150,000 bbl. a day. The outstanding development of the year was an intensive drilling campaign in southwestern Kansas, which contributed at least 1,000,000 acres of contiguous natural-gas lands to the natural-gas resources of the United States. Production and Development Prospecting for oil in Kansas began shortly after the initial prospecting at Titusville. Operations and interest in the potentialities became active about 1870. This development was restricted to the shallow districts of northeastern Kansas. By 1895 operations had extended southward to the Oklahoma state line and sufficient prospecting had taken place to prove the potentialities of the state. Active prospecting was extended westward by the discovery of oil on the Nemaha Range in Butler County about 1916. The discovery of oil in Russell County added an extensive borderland province in 1923. The important discoveries of oil in Sedgwick County revived interests and operations throughout this territory in 1928. The development of widespread natural-gas lands in extreme southwestern Kansas during 1930 carried active exploration to the western boundary of the state.

Jan 1, 1931

By N. A. D. Parlee, I. D. Shah

ThIS reports on some work done on the solubility and diffusivity of oxygen in liquid silver. Solubility. Improvements in the measurement of the solubility of oxygen in silver and silver alloys were made because precise data were needed for calculating diffusion coefficients of oxygen in these alloys. The apparatus and the procedure used were similar to those of Parlee and Sacris.' The main improvement was in the temperature-measuring technique. A MV30 mullite protection tube containing a calibrated Pt-Pt, 10 pct Rh thermocouple was inserted in the reaction tube from the top through a vacuum-tight swage-lok fitting. The protection tube was well-immersed in the liquid silver, which was heated by induction. A Leeds and Northrup potentiometer was used in connection with the thermocouple. All runs reported were made at 1 atm. The temperature range investigated varied from 940" to 1200°C. The ternary point in Ag-0 phase diagram2 is at 939°C and 0.32 wt pct O. This point was reinvestigated using the above-described apparatus and was found to be at 939°C and 0.315 wt pct 0. It was determined by observing the sudden evolution of oxygen at this point while the solubility measurements were made. The point was easily reproducible if precautions were taken to keep the liquid silver essentially in equilibrium with oxygen and to lower the temperature very slowly. All of the results of this new solubility investigation are plotted in Fig. 1. They are represented by the "least-squares" line shown in the figure and the following equation for solubility at po2 = 1 atm: log% O =695.4/T - 1.086 This equation differs only slightly from that proposed by Parlee and sacrisl and that of Diaz, Masson, and Richardson.3 The points of Parlee and Sacris, using an optical pyrometer, are shown for comparison.

Jan 1, 1968

By Frank Haas

Many articles on the physical properties of fire damp have appeared in the Transactions and elsewhere but practically nothing has been written in regard to its occurrence or fluctuation in quantity in an ordinary mine. After the Monongah explosion in 1907, with the loss of 361 lives, the Consolidation Coal Co. sought a method by which such catastrophes could be prevented. While the cause of this particular explosion was attributed to coal dust, some of those acquainted with the mine thought that fire damp was involved, if it was not the initial cause. So the literature on the subject was studied and mines where similar conditions prevailed in this country and Europe, were visited, with the view of establishing some system by which gas could be more easily detected and controlled. The results of this study were disappointing for no method was found other than the time-honored fire boss with his safety lamp, with some variations in the rules and regulations governing his inspections and reports. Duties of the Fire Boss Pending the development of a better method, it was decided to standardize and perfect the duties of the fire boss and the reports based on his observations. Those who were then in service were closely examined, various lamps were experimented with and the lamps and individuals tested under known conditions. It was found that a fire boss could tell whether gas was present but his estimate of quantity was not even an approximation; therefore, while the services of fire bosses were indispen-sible there was need of additional information by which the quantity of gas could be estimated with some precision in order to determine its variation from time to time. Chemical Process for Determination of Methane After considering all methods known at that time a chemical process was adopted. The principles involved in the process are that in an enclosed receptacle, in the presence of excess air, methane will be completely burned by means of a hot platinum wire to carbon dioxide and

Jan 1, 1927

By Edward Keller

THE ASSAY FOR COPPER. SOMEONE some time ago remarked that some chemists still insist on telling us how to determine copper by the electrolytic method. The. writer must confess that he believes that everything is not known definitely as yet as to how the exact amount of copper is determined in such material as purest commercial electrolytic copper. Some of us are not yet convinced that the pure copper atom is at all times deposited from an acid solution and that no oxygen or hydrogen will, under certain conditions, accompany it. Difficulties with impurer material are frequent, but erroneous results are not always apparent, since these do not speak so readily for themselves as those in the first case. By this is meant that if a chemist finds 100 per cent. of copper in electrolytic copper it is pretty certain that he perceives the result to be wrong, while if he finds 0.1 per cent. of copper too much in a very impure material he is far more likely to be unconscious of his error. These, in a wide experience, are frequent happenings and the writer has always looked with interest to publications on this subject. In turn, he :feels justified in giving to others a few of his own observations. Up to a few years ago there were two methods of electrolytic copper assay in technical use, which had in common, that the amount of copper deposited on the cathode did not exceed 2 g., and they differed in that, for the one a large sample 1 (20 to 80 g.) was taken from the general sample by a splitting device, dissolved, and from the solution a small portion (to contain 1 or 2, g. of copper) measured out for the electrolytic deposition; in the other Method the copper was determined, generally in 1-g. portions of the separated coarse and fine portions of the sample, all of which passed -a 16 or 20-mesh screen, being accomplished by a 40-mesh screen,

Jan 8, 1913

By John E. Carr

A bewildering variety of continuous thickeners and clarifiers are used in mineral industries and other heavy industries. General topes arc: ? Conventional thickeners ? Thickeners with flocculating feedwells ? Solids contactors ? Tray thickeners ? Lamellas ? Conventional thickeners with Lamellas ? High flow, fluid bed thickeners These units must be adapted to varied applications. They must provide operating flexibility to meet process needs. Such factors multiply the decisions which must be made prior to the selection of a thickener. The seven types of thickeners listed above, with their variations, share design concepts which limit their application and which can be used to evaluate their performance. Some of these arc: ? Feed velocities must be limited and/or controlled. ? Natural or reagent flocculation is necessary. ? Horizontal settling area is the basis for capacity. ? Overflow velocities must be limited and. or controlled. ? A controlled underflow is necessary. Thickener selection is the application of these needs to the basic process concepts. The basic function of a thickener, in the minerals industry, is the separation of a thickener sludge containing fine solids from water. In addition to this primary separation function, others include: ? Separation of solids from water ? Separation of flocculated solids from slimes ? Storage of solids ? Control of percent solids ? Storage of water ? Process control by absorbing fluctuations in feed ? Process control by increase in head clue to the depth and percent solids of the thickened sludge. Most thickener designs, suitable to minerals applications, are based on the separation of minus 65-mesh, 2.7 specific gravity solids containing slimes. These designs are routinely adapted to coarse and or denser materials. Materials of lower specific gravity such as coal, wood, char, some chemical precipitates and organics act Hike slimes if a thickener is used. Perhaps the most conservative approach to sizing and application is the use of comparative data from similar plants or similar industries. Thickeners are-routinely used in a great number of industries from which there is good historical information available. In the minerals industry, thickeners are used in: clay sizing, coal refuse, heavy media, copper concentrates, copper tailings, gold flotation concentrates, and countercurrent decantation for cyanidization in gold and CCD in uranium. Concentrate and tailings thickeners are used in iron ore plants, and concentrate and tailings units in lead-zinc plants. In addition, there arc thickeners designed to handle lime mud; limestone concentrates and tailings; phosphoric acid; potash; and rutile concentrates. Thickeners are, in addition, widely used in gravel plants for water reclamation. This gives excellent data on clay settling in some cases. Thickeners are used extensively for slurries generated by flue dust from wet scrubbers. Thickeners in flue dust applications are operating with considerable variations, treating blast furnace dust. BOF flue dust, and wood char. Similar applications are met in the power industry with fly ash and SO2 scrubber systems. Even though field data is preferred, such data has limitations as listed: ? Flowsheets are seldom identical. ? Data is often incomplete or limited. ? Ores vary significantly. ? Operating needs are changing. For these reasons, mathematical and theoretical methods are needed for application of field data to a specific project. In addition, laboratory data for similar projects and, if possible, laboratory data on a representative sample should be used to specify the thickener. There is a great volume of thickener literature. The references for this paper, along with their references, and past AIME papers provide excellent background. Older literature can be reviewed in light of current methods. It is interesting to note that the requirements for higher flow rate designs, more extreme flocculation systems, etc., can be logically introduced by reading Gaudin's Sections on Flocculation and Thickening, which was written before field installations could illustrate all of his ideas. The problem, then, is to select hardware which will take into consideration the functions of flocculation, separation of the solids, water clarity, control of the underflow, and control of the overflow. Reliable operation and simple control are customary.

Jan 1, 1979

By Alexander N. Mitinsky

Up to a certain limit, the increase of pressure on the diamond-drill increases the rate of progress in drilling. That limit is set by the resistance of the diamonds to compression; and beyond it, the destruction of the stones will involve an economic loss, both in time and in money. It is, therefore, important to all diamond-drillers to know what is the resistance mentioned. In Europe, operators usually follow an empirical rule, which directs the maintenance of a pressure, on the area of the bottom of the drilling-tool, of 12 kg. per sq. em. For the tools in ordinary use, this is equivalent to 1 kg. per sq. mm. of the diamonds set in the tool. So far as I know, American drillers are using pressures as high as 50 to 60 kg. per sq. em. of the total area of the drill, and the consumption of diamonds (on Denny's authority, 0.2 carat per meter bored) is greater in America than in Europe. But the reason for this diffrence may be the comparatively larger size of the diamonds commonly used by American drillers. With the assistance of my friend, the late S. Woisslaw, who was the pioneer of diamond-drilling in Russia, I selected from his stock a number of black diamonds, which I subjected in my laboratory to compression-tests, To prepare regular cubes for such tests, as is generally done with other stones, would have been not only costly, but, what is more important, practically useless. I therefore determined, in order to assimilate as nearly as possible the conditions of actual use, to place each sample between a hard plate (corresponding to the rock) and a softer plate (corresponding to the bottom of the tool), into which it would be pressed during the test.

Jan 1, 1907

By Adelaide Ross Smith

Both history and physical examination are unreliable in the diagnosis of silicosis. In some studies 25 per cent of individuals with silicosis have been found to have no symptoms whatever. The positive physical findings that may be produced by this disease include diminished chest expansion, diminished lung resonance, distant and harsh breath sounds. However, many workmen of a short stocky type have diminished chest expansion without any lung disease. In a study of rockdrillers made by the author more than half of the men without silicosis were limited in chest expansion to 2 in. or less instead of the "normal" 6. In a study of stonecutters the average chest expansion in the negative group was found to be only 2.4 inches. Changes found upon physical examination of the lungs themselves are so inconstant as to be of little diagnostic value. In the studies of rockdrillers and stonecutters already referred to, approximately 25 per cent of those with advanced silicosis apparently had normal lungs. The usual functional tests of lung performance are likewise of little value because of marked individual variation. Average vital capacity will be reduced in a group of silicotics below what might be expected in a group of normals, but certain individuals of the former group may have an entirely vital capacity, giving no indication of the underlying presence of silicosis. It follows that the X-ray examination is absolutely indispensable in the diagnosis of this disease. X-ray findings characteristic of silicosis have been described innumerable times. They consist essentially of a mottling of the lung fields due to the presence of fibrous nodules which develop as a reaction to the presence of the irritant silica.

Jan 1, 1934

By Pope Yeatman

THE Committee on the Elimination of Waste in Industry, of the Federated American Engineering Societies, in its report says that "Waste in -industry is attributable to four causes: 1. Low production, caused by faulty management, of materials, plant, equipment, and men; 2. Interrupted production caused by idle materials, idle plants, and idle equipment; 3. Restricted production intentionally caused by ,owners, managers, or labor; 4. Lost production caused by ill-health, physical defects and industrial accidents. The committee sent out elaborate questionnaires, and in them divided the responsibility into Manage-ment, Labor, and Outside Contracts. These question-naires showed that in the different industries examined the responsibility of Management was from 50 to 80 per cent. and of Labor from 9 to 28 per cent. The percentage of responsibility that Management was held accountable for was much larger than any of us supposed. However, when this question is studied, we realize how necessary it is to select, in the first instance, suitable personnel, in the form of directors, managers, heads of departments, experts, etc. We would like to -believe that the percentage of responsibility of Management for waste in the mining business was less than that quoted above, but there are so many mining properties started up and operated by men of no experience in such lines, and there have been so many improvements in late years in mining and metallurgical methods not taken advantage of, that we can not believe that. the percentage will vary much from that already quoted. Quoting from a report approved by the Committee on Management of the American Society of Mechanical Engineers: Management is the art and science of preparing, organizing, and directing human effort applied to control the forces and util-ize the materials of nature for the benefit of man.

Jan 3, 1922

This brief resume of events, transpiring in Mexico, culled from the daily New York newspapers, since the last Bulletin went to press, does not indicate any degree of improvements in the situation. GENERAL ALVAREZ COURTMARTIALED AND SHOT General Francisco Alvarez of the anti-Government forces was captured in the battle in which General Aureliano Blanquet, Minister of War in the Huerta Cabinet, was killed, and was sentenced by a courtmartial and shot in spite of a specific order of the Supreme Court in Mexico City that the execution should not take place. General Alvarez was a member of the staff of Felix Diaz, and was a veteran of the old regular army of Mexico. MEXICO WILL NOT RECOGNIZE MONROE DOCTRINE Failure of the Allied Powers to invite Mexico to participate in the conference of neutrals at Paris aroused President Carranza to bitter resentment, which was enhanced by the incorporation of recognition of the Monroe Doctrine in the covenant of the League of Nations without consultation with Mexico. Statements were issued by the Mexican Foreign Office disavowing adherence to the Monroe Doctrine and announcing the withdrawal of the Mexican representative in France. Carranza had been awaiting an opportunity to get his agent away from Paris for the real reason that he had been unable to secure recognition from either the French or the British Government. Mexico announces, says the New York Times editorially, that "she has not recognized and will not recognize the Monroe Doctrine." "Nobody has asked her to recognize the Monroe Doctrine," continues the editorial. "The enforcement of the principles enunciated by President Monroe does not depend upon Mexico, upon anybody's recognition or non-recognition. The countries concerned in the Monroe Doctrine are the United States on the one hand, and countries not of this hemisphere on the other."

Jan 6, 1919

By Thomas V. Falkie

The three basic ingredients of fertilizers are nitrogen, phosphorus, and potassium. Nitrogen comes from natural gas or other sources and is usually a "manufactured" ingredient. Phosphorus and potassium come from mineral sources which are mined in open pit and underground mines all over the world. Phosphorus is one of the 15 chemical elements needed to sustain life. Along with nitrogen and potassium, it is essential to the fertility of the soil and to the growth of plant life. Plants require phosphorus for proper soil conditions, early root formation, and crop maturity. Humans and animals require phosphorus for bone and tooth development. The primary raw material for phosphorous fertilizers is phosphate rock. It is found and mined in many areas of the world. Morocco, the United States, USSR, Tunisia, and some Pacific Islands are the leading rock producers. Other sources of phosphate are guano, bone meal, and other natural organics, but these comprise a very small percentage of all phosphate used. Phosphate rock in the United States is mined in Florida, North Carolina, Tennessee, Idaho, and Montana. Florida alone produces about 70% of all the rock mined in this country, mostly from a 20 X 30 mile area in Polk and Hillsborough Counties in central Florida known as the Bone Valley district. There are phosphate reserves in many parts of Florida, and within the past three years mining has begun in north Florida in Hamilton Country (see Fig. 1). In 1967, world phosphate rock production was about 75 million short tons (st). The United States produced about 35 million st (about 47%) of which Florida produced about 25 million st (about one-third of world production). According to Phosphorus and Potassium magazine (Mar./

Jan 1, 1969

By M. Friedman

Applications of rock mechanics to the design of engineering structures in rock involve the assumption that the stresses are due entirely to the present applied loads. For instance, it is assumed that the vertical normal stress in undisturbed rock free of topographic effects is equal to the weight per unit area of the overburden. In fact, vertical dilatational strains associated with stresses of more than 100 times the present overburden pressure have been measured by strain-relief methods on outcrops. 1,2 The notion of residual strain (stress) or latent stress3 seems unassailable; and indeed this has long been recognized by metallurgists. It is difficult, however, to assess the residual component of the in-situ state of elastic strain with conventional strain relief methods employed in mines or down boreholes. That is, in principle, the in-situ state results from the superposition of present applied loads (natural or man- induced) and potentially recoverable elastic strains (stresses) that exist in a given volume of material even though there are no external forces across the boundaries of the body (Voight,4 and Fig, 1). Accordingly, only in unloaded blocks can the true residual strains be measured by strain relief methods. Using X-rays, the elastic strains locked within the quartz grains or crystals of a rock can be measured. These strains are known to persist even when the rock is reduced to small chips but to vanish when the rock is disaggregated and the grains are powdered. Although we have just begun to investigate the mechanisms by which the strains are stored (see Preliminary Results), we believe that "pressure solution'' at grain boundaries, secondary cementation under load, permanent ("plastic") deformation, and temperature changes are possible processes. In any event, in our study of naturally deformed rocks, it is significant that we are work-

Jan 1, 1972

By Charles Barrett

PLASTIC flow in metal crystals and the changes in orientation resulting from it are generally understood to take place by the following funda-mental mechanisms: (1) slip on crystallographic planes, (2) homogeneous crystal rotation resulting from the slip, (3) bending of the lattice between the planes of slip, and, under certain circumstances, (4) twinning. This paper and a preceding one on iron subjected to uniaxial compression1 concern two additional processes that must now be added to this list: (5) the formation of deformation bands, and (6) the bending and rotation of these bands. The present investigation yields a new understanding and definiteness to the common terms so loosely used when speaking of cold-worked metals -"grain fragmentation," "elongated grains," and "deformation twins," "deformation bands," "etch bands," or "X-bands." Bands have been noted on the polished and etched surfaces of cold-worked metals by vari-ous investigators for more than 25 years, ? yet their nature and their significance have been so little understood that they are not treated in the most comprehensive modern texts on the deformation of crystals. The experiments in this series show that they are one of the fundamental processes in the deformation of metals, of importance in the development of preferred orientations, in work-hardening (since they have the effect of reducing the effective grain size and interfering with slip), and in the recrystallization process. The present experiments were performed on the same stock of mate-rial that was used in the earlier compression experiments1-hydrogen-purified mild steel in which the carbon content had been reduced to the limit detectable under the microscope and in which single crystals could be grown by a strain-anneal treatment.2

Jan 1, 1939

By T. L. Berger, M. C. lnman, M. F. Rose

AFTER shock loading, mechanical twinning has been observed by several authors1-4 for a variety of fcc metals and alloys. It has been shown2,3 that low stacking fault energy materials deform primarily by the formation of mechanical twins and stacking faults during dynamic loading. Further, Inman, Murr, and Rose2 have shown that a correlation exists between the average hardness and the volume percent of mechanically twinned material in stainless steel. It has been observed in nickel' that mechanical twins are produced during shock deformation if the peak pressure associated with the shock wave is greater than 350kbar. It is the purpose of this work to discuss shock-hardening mechanisms in nickel and to determine to what extent the initial condition influences the final response. The "flying plate technique" was used to generate planar shock waves with peak pressures as high as 710 kbar. The details of the technique5" have been discussed elsewhere and will not be repeated here. The material used in this study was polycrystalline nickel of 99.98 pct purity and had an initial grain size of 0.18 mm. Prior to any deformation, all samples were given a stress-relief anneal of 6 hr at 600°C in a vacuum furnace. After annealing, the initial condition of the samples was changed by cold rolling individual samples from 0 pct to a maximum of 80 pct reduction in thickness. This provided samples with controlled initial histories for shock deformation. Immediately after shock loading, the specimens were slowed and quenched by suitable arrangement of buffer material and water bath. This technique minimized specimen damage and the effects of shock heating on the samples. Since deformation twins in high stacking fault energy fcc metals are only produced at high stress levels, the initial defect configuration prior to mechanical twinning should greatly influence the number of twins formed. In fact, Zukas and Fowler7 have found that prestraining in iron and steel greatly suppresses the formation of mechanical twins during the shock deformation process. Following the methods of Warren and warekois8 and Cohen and Wagner,9 X-ray diffraction profile analysis was performed to determine the incidence of stacking faults and mechanical twins in the deformed nickel. Analysis was made on samples in the annealed, cold-rolled, shock-loaded, and cold-rolled—shock-loaded states. The estimated accuracy of the peak position measurements is *0.01 deg in 2?. Therefore the accuracy in the measurement of the relative peak shifts between the (400) and (222) diffraction line profiles is on the order of *0.04 deg in 2?. None of our measurements indicated peak shifts greater than 0.04 in 28. This would correspond to a fault density of -1 pct and sets the limit on the sensitivity of our instrument. Similarly, analysis of the shift in the center of gravity of the diffraction line profiles yields the minimum measurable value of the twin fault probabilitya to be -0.002. Fig. 1 shows mechanical twinning in nickel shock-loaded to 400 kbar. In this photograph, fault intersections are clearly visible. The thickness of the individual fault lamellae was determined from the image widths of their lines of intersections by the

Jan 1, 1968

By M. N. Dastur

In this paper, the current situation in iron ore pelletization in developing countries is reviewed. The main reasons leading to the development of pelletizing in these countries, alternative pelletizing methods and feed materials utilised, are illustrated with typical examples. The major factors which may influence the future growth are discussed and trends of development in the immediate future, till 1978, examined. The probable pelletizing capacity by 1985 is projected.

Jan 1, 1977

This brief resume of events, transpiring in Mexico, culled front the daily New York newspapers, since the last Bulletin-went to press, does not indicate any degree of improvement in the situation. RECORDS OF 217 MEXICO KILLINGS SUBMITTED BY AMBASSADOR FLETCHER Henry P. Fletcher, the American Ambassador to Mexico, called as the first witness before the Rules Committee of the House which has begun a preliminary inquiry into conditions in Mexico, which, it, is believed, will lead to a thorough and far-reaching investigation by a joint Senate and House Committee of the entire Mexican problem, submitted a list of the names of Americans officially known to have been killed in Mexico, a majority of them murdered in cold blood, since the overthrow of Porfirio Diaz by Maderoin 1911. The list contains 217 names and in comparatively few instances do the records show that arrests were made by the particular Mexican faction that happened to be in power where the crime was committed. In only one instance, that of John B. McManus, who was killed in March, 1915, was reparation made. It is significant that McManus was killed by Zapatistas, and Zapata officials apologized for the crime and paid to Mrs. McManus a voluntary indemnity of $20,000 in gold. Of the 217 persons listed as victims of the Mexicans, .137 perished since Carranza came into power. The list, it was admitted, is not complete. It was evident, says the New York Times, that the Ambassador considered the situation very serious.

Jan 9, 1919