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By W. M. Mobley

THE coal industry in Alabama, centered in Birmingham, has pioneered coal-beneficiation practice in the United States. The nature of the coal seams and mining methods employed have necessitated use of equipment and methods best adapted to the local conditions. Although all of the 30 or more coal seams now being mined in the state receive beneficiation, only the three most important producers of coking coals, the Pratt, Mary Lee and Black Creek, are discussed in detail. Nature of the seams, washability characteristics and equipment used are given as examples of the extent of work and progress in this field. The coal seams in Alabama are relatively thin and pitching, making mining difficult and expensive. Most of them are characterized by thin partings of rock or shale in the seam itself, as well as laminations of bone and rash. Mechanical mining methods have increased the occlusions from roof and floor to such an extent that nearly all the coal mined in the state must receive some treatment before it can be put on the market. During the year ending Sept. 30, 1943,1 18,129,792 tons of coal were mined in the state and 14,364,177 tons, or 79.2 per cent, received treatment. Excluding from the total the 1,223,014 tons produced by small wagon mines and the hand-picked lump coal, the amount receiving beneficiation would be more than 90.00 per cent. This is, by far, greater than in any other coal-producing state. The earliest record of coal beneficiation in Alabama was the installation in 1890 of an experimental Lung washer by Alexander Cunningham, for the Sloss Iron and Steel Co. at its blast furnace in Birmingham .2 In 1894 the Jeffrey Manufacturing Co. introduced the English Robinson washer, a combination of a hydraulic classifier and centrifugal machine. Erskine Ramsay, who has contributed so much to the coal industry, saw its possibilities as well as its mechanical defects and soon had his inventive mind at work. He added a sludge tank of his own design, and many Robinson-Ramsay washers were installed in Alabama and other states. The Stewart jig appeared in 1900, followed by the Montgomery jig in 1910 and both have found extensive use. Increased interest in this field led to new designs, such as the American, Elmore; Burke and Faust. The first Baum-type Norton jig was operated in 1930 and within the last five years six large installations of this type have been made by the McNally-Pittsburg, Jeffrey and Link-Belt Companies. Wet-washing tables were introduced in 1922 but not extensively used until recently. The two most popular types are the Deister-Overstrom and Deister Plat-O. The coal-cleaning equipment used in Alabama has been relatively simple, yet efficient, but as the amount of impurities in the raw coal has been increased by mechanical mining and labor costs have become higher, much interest has been shown in sand cones, froth flotation and

Jan 1, 1945

By W. M. Mobley

The coal industry in Alabama, centered in Birmingham, has pioneered coal-bene-ficiation practice in the United States. The nature of the coal seams and mining methods employed have necessitated use of equipment and methods best adapted to the local conditions. Although all of the 30 or more coal seams now being mined in the state receive beneficiation, only the three most important producers of coking coals, the Pratt, Mary Lee and Black Creek, are discussed in detail. Nature of the seams, washability characteristics and equipment used are given as examples of the extent of work and progress in this field. The coal seams in Alabama are relatively thin and pitching, making mining difficult and expensive. Most of them are characterized by thin partings of rock or shale in the seam itself, as well as laminations of bone and rash. Mechanical mining methods have increased the occlusions from roof and floor to such an extent that nearly all the coal mined in the state must receive some treatment before it can be put on the market. During the year ending Sept. 30, 1943,' 18,129,792 tons of coal were mined in the state and 14,364,177 tons, or 79.2 per cent, received treatment. Excluding from the total the 1,223,014 tons produced by small wagon mines and the hand-picked lump coal, the amount re- ceiving beneficiation would be more than 90.00 per cent. This is, by far, greater than in any other coal-producing state. The earliest record of coal beneficiation in Alabama was the installation in 1890 of an experimental Lurig washer by Alexander Cunningham, for the Sloss Iron and Steel Co. at its blast furnace in Birmingham.2 In 1894 the Jeffrey Manufacturing Co. introduced the English Robinson washer, a combination of a hydraulic classifier and centrifugal machine. Erskine Ramsay, who has contributed so much to the coal industry, saw its possibilities as well as its mechanical defects and soon had his inventive mind at work. He added a sludge tank of his own design, and many Robinson-Ramsay washers were installed in Alabama and other states. The Stewart jig appeared in 1900, followed by the Montgomery jig in 1910 and both have found extensive use. Increased interest in this field led to new designs, such as the American, Elmore, Burke and Faust. The first Baum-type Norton jig was operated in 1930 and within the last five years six large installations of this type have been made by the McNally-Pitts-burg, Jeffrey and Link-Belt Companies. Wet-washing tables were introduced in 1922 but not extensively used until recently. The two most popular types are the Deister-Overstrom and Deister Plat-O. The coal-cleaning equipment used in Alabama has been relatively simple, yet efficient, but as the amount of impurities in the raw coal has been increased by mechanical mining and labor costs have become higher, much interest has been shown in sand cones, froth flotation and

Jan 1, 1947

By W. M. Mobley

The coal industry in Alabama, centered in Birmingham, has pioneered coal-bene-ficiation practice in the United States. The nature of the coal seams and mining methods employed have necessitated use of equipment and methods best adapted to the local conditions. Although all of the 30 or more coal seams now being mined in the state receive beneficiation, only the three most important producers of coking coals, the Pratt, Mary Lee and Black Creek, are discussed in detail. Nature of the seams, washability characteristics and equipment used are given as examples of the extent of work and progress in this field. The coal seams in Alabama are relatively thin and pitching, making mining difficult and expensive. Most of them are characterized by thin partings of rock or shale in the seam itself, as well as laminations of bone and rash. Mechanical mining methods have increased the occlusions from roof and floor to such an extent that nearly all the coal mined in the state must receive some treatment before it can be put on the market. During the year ending Sept. 30, 1943,' 18,129,792 tons of coal were mined in the state and 14,364,177 tons, or 79.2 per cent, received treatment. Excluding from the total the 1,223,014 tons produced by small wagon mines and the hand-picked lump coal, the amount re- ceiving beneficiation would be more than 90.00 per cent. This is, by far, greater than in any other coal-producing state. The earliest record of coal beneficiation in Alabama was the installation in 1890 of an experimental Lurig washer by Alexander Cunningham, for the Sloss Iron and Steel Co. at its blast furnace in Birmingham.2 In 1894 the Jeffrey Manufacturing Co. introduced the English Robinson washer, a combination of a hydraulic classifier and centrifugal machine. Erskine Ramsay, who has contributed so much to the coal industry, saw its possibilities as well as its mechanical defects and soon had his inventive mind at work. He added a sludge tank of his own design, and many Robinson-Ramsay washers were installed in Alabama and other states. The Stewart jig appeared in 1900, followed by the Montgomery jig in 1910 and both have found extensive use. Increased interest in this field led to new designs, such as the American, Elmore, Burke and Faust. The first Baum-type Norton jig was operated in 1930 and within the last five years six large installations of this type have been made by the McNally-Pitts-burg, Jeffrey and Link-Belt Companies. Wet-washing tables were introduced in 1922 but not extensively used until recently. The two most popular types are the Deister-Overstrom and Deister Plat-O. The coal-cleaning equipment used in Alabama has been relatively simple, yet efficient, but as the amount of impurities in the raw coal has been increased by mechanical mining and labor costs have become higher, much interest has been shown in sand cones, froth flotation and

Jan 1, 1947

By John W. Bell

IN the introduction to an excellent pamphlet, John Gross1 makes the following statements: Although marked progress has been made along mechanical lines, the theory and conception of underlying principles have not advanced so rapidly. This lack of advance in theory may be attributed to the unfortunate situation resulting from the controversy as to whether the Rittinger or Kick law is applicable to crushing. Many pages of the technical literature are burdened with theoretical discussions in favor of one or the other of these laws, which have tended to cloud rather than to clear the atmosphere. Realizing the situation, the Milling Committee of the American Institute of Mining and Metallurgical Engineers, through its secretary, E. A. Hersam, studied the milling industry and, because of the apparently hopeless lack of agreement in the Kick versus Rittinger dispute (5, 13, 14, 16, 18, 19, 21, 22, 23, 24, 30. 34), concluded that a foundation for the theory of crushing was of primary importance. The numbers in the paragraph quoted refer to papers listed by Mr. Gross in his Bibliography on Crushing and Grinding.1 One is obliged to infer that these papers show "hopeless lack of agreement in the Kick versus Rittinger dispute." No. 22 is a paper by Arthur O. Gates2 and No. 23 is one by the writer.3 Employing the subject matter contained in papers Nos. 22 and 2323 the writer will show that their authors formulated identical conclusions, based solely on experimental evidence. Exactly the same defect in the Stadler hypothesis was described in each of the two papers, although entirely different experimental methods were employed in uncovering it. Both of the authors, independently, formulated the conclusion that Rittinger's was a. true hypothesis and Stadler's false. The evidence in a third paper4 will be employed to prove that Stadler's hypothesis, when examined experimentally, is worthless. STADLER'S HYPOTHESIS WORTHLESS It is the writer's opinion that the evidence available in 1915 and the corroborating evidence in 1916 was amply sufficient to eliminate the need for any further consideration of Stadler's hypothesis. Certainly the evidence produced in 1918 dealt this hypothesis its coup de grace. It follows, therefore, that in the year 1918 there was only one credible hypothesis left-the Rittinger hypothesis. Gates' Opinion What information is available in Mr. Gates' paper?2 His conclusions are not consecutively summarized, none the less they are perfectly clear. On page 876, Gates says, and it is a very significant utterance: But my results show, among other things, that many more of Stadler's energy units are obtained per foot-pound-applied in coarse than in fine crushing. This suggests a doubt as to the correctness of his unit, since one would expect a foot-pound-applied to produce the same number of "energy units," whether the feed and resulting product were coarse or fine. When Rittinger's theory is applied, the number of mesh-tons (my unit of surface produced) is

Jan 1, 1942

By W. D. Von Gonten, R. L. Whiting

Regression analysis was used to correlate the physical properties of 478 sandstone and 90 carbonate core samples. Porosity, permeability, electrical formation resistivity factor, capillary pressure and the sonic velocity of the shear and compressional waves were measured. Prediction equations for porosity, permeability and electrical formation resistivity factor were found which should be useful in understanding the relationships between the physical properties of porous media in formation evaluation. INTRODUCTION The physical properties of porous media are important to the petroleum engineer and geologist. To evaluate fully the potential and behavior of a subsurface formation such as a petroleum reservoir, certain physical properties of the porous medium must be known. The problem of accurately determining physical properties of subsurface formations has not been solved because many determinations must be made by indirect measurements and because of the difficulties caused by complex pore structure and presence of clays in most naturally occurring porous media. Due to the difficulty in measuring some of the physical properties of porous media, it would be advantageous to be able to predict a certain physical property of a rock from other physical properties of the rock which could be measured more easily and more accurately. Since most potential reservoir rocks are heterogeneous, relationships between the physical properties are very complex and thus far no satisfactory correlations based on theory or laboratory models have been developed. It appears that empirical relationships obtained by measuring the physical properties of a large number of samples of naturally occurring porous media and applying regression analysis to develop equations for one physical property in terms of other rock properties is the best approach. REVIEW LITERATURE The three physical properties used as dependent variables for correlating purposes were porosity, permeability and formation factor. Since formation factor is more difficult to determine, a brief review of the literature is provided on this property. The first work on determining formation factors was published by Archie1 in 1942. He defined this property of a porous medium as F - Ro/Rw......(1) where Ro is the resistivity of the porous medium when completely saturated with a brine of resistivity Rw. Archie found the best correlation between formation factor and porosity was the following equation, where is the porosity fraction and m is the constant characteristic of the rock. The value of m was 1.3 for unconsolidated sand packs, and ranged from 1.8 to 2.0 for consolidated sandstones. In 1950 Patnode and Wyllie2 and De Witte3 observed that the formation factor as determined by Eq. 1 was valid only when the porous medium contained no conductive solids such as clay or shale. When conductive solids are present the formation factor is also dependent on the resistivity of the saturating fluid. Therefore, in samples containing conductive solids the formation factor decreased as the resistivity of the saturating fluid increased. Because of this. the measured formation factor was called the apparent formation factor and was designated Fa. Patnode and Wyllie proposed the following equation,

By John P. Dolan, Charles A. Einarsen, GiIman A. Hill

his paper discusses how the following formation characteristics can be determined mathematically from drill-stem test pressure charts: true formation pressures, effective permeability of the entire section tested, well productivities, wellbore damage, and possible detection of barriers (faults, pinchouts, etc.). This paper also presents a practical method for im-mediate determination of eflective permeability and well-bore damage from successful double shut-in pressure tests. A list of recommendations for improving the reliability of drill-stem rest pressures is also presented. INTRODUCTION A drill-stem test is a temporary completion designed to sample the formation fluid and to establish the possibility of commercial production. Early pressure recording devices were used merely to verify proper operation of the testing tool. Until recently the accuracy of the pressure gauges has been insufficient for any reliable quantitative use of the recorded pressures. In view of the need for more reliable formation evaluation and as a result of the recent interest in exploration work employing the concept of hydrodynamic en-trapment,1,2,3,4 better pressure recording gauges are now in use. These devices can record pressure within 1 per cent above 1,000 psig and can detect differential pressures as low as 1/2 psig. In addition to formation pressure, several other reservoir characteristics can be determined from DST charts; namely, well productivity, formation permeability, wellbore damage, and the possible existence of bar- riers (faults, pinchouts, changes in permeability, etc.). This paper presents a practical method to interpret DST pressure charts for formation pressures and many other reservoir properties, a method that has been developed in analyzing approximately 4,000 DST charts during the last five years. The techniques used are a composite of published articles on drill-stem testing5,6, together with well-known pressure build-up analysis methods. THEORY It has been shown7,8 that the following equation may be used for analysis of pressure build-up curves: Po - Pw = 162.6 qu/kh log ( to + ?/?) .....(1) When this equation is applied to the curves obtained in drill-stem testing, the assumptions and boundary con-ditions are more nearly realized than in conventional flow and build-up tests on producing wells. Zak and Griffen9 have recently discussed in detail the use of this equation in analyzing DST charts. One of the problems with DST curves is the lack of reservoir data for precise analysis. Therefore, it is necessary to develop empirical rules and field methods for analyzing DST charts in quantity. For this reason, the empirical methods presented in this paper have been developed, and their derivation is found in Appendices A and B. METHOD USED FOR ACCURATE READING OF DRILL-STEM TEST CHARTS In order to apply the pressure build-up theory to DST charts, it is necessary to obtain a digitized expression for the pressure and time data recorded by the pressure gauge. These data may be either provided by the service company or interpolated by projecting a

Jan 1, 1958

By Roy J. Helfinstine, Gilbert H. Cady

One of the most urgent needs in the field of coal combustion is the ability to predict the performance of a coal from knowledge gained from small-scale tests. Numerous types of analyses and tests are conducted on coal, including the proximate and ultimate analyses, heating value, varieties of sulphur, ash analysis, ash fusion temperatures, free swelling index, petrographic analysis, and Gieseler. plasticity. The Illinois Geological Survey has made an intensive study of the value of these tests for judging the performance characteristics of the coal as actually utilized. To date, three reports1,2,3 have been issued, and another is being prepared. The present paper briefly summarizes some of the results found in the studies. Equipment The equipment used for the tests is described in some detail in the above mentioned publications. Briefly, it consisted of a domestic stoker, cast-iron boiler, and water-cooled heat exchanger, which were operated as a forced circulation hot-water system. The entire unit was mounted on scales. Instruments for recording the per- formance of the coal included a hot-water meter to indicate the quantity of water flowing through the boiler; a two-pen, mercury-actuated thermometer to record the temperatures of the water entering and leaving the boiler; a chemical-type meter to record the percentage of CO2 in the stack gases; a pressure gauge to record the static pressure in the stoker-air duct; and a multipoint potentiometer to record the temperatures in the stack and room, and the opacity of the stack gases. A 16 mm motion picture camera was available for taking pictures of either the fuel bed or the scale dial. Procedure The tests described in this report can be conveniently divided into three phases. For the first phase, a load of 5 or 6 tons of unwashed coal (usually screenings) was obtained from each of fourteen Illinois mines. These coals were all crushed and screened to a size of 35 in. (square hole) by 8 mesh. Combustion tests were made on a part of this raw, screened coal. Another portion was passed over a concentrating table to reduce the ash to what was considered to be commercially reasonable, and combustion tests were made on this upgraded coal. The ash content of the remaining coal was reduced to a still lower figure by passing it over the washing table with greater reject, or by standard float-sink procedure. This cleaned fraction was then tested in the stoker-boiler unit. Thus three coals with varying ash content were tested from each mine. For the second phase reported here, coals were obtained from four Arkansas mines and tested as received and after passing over the concentrating table with a normal reject. One Illinois coal was tested in the "washed" condition only. The third phase included tests on commercially prepared stoker coals

Jan 1, 1950

The Palabora ore consists of two types, a carbonatite containing a low titanium magnetite, and a foskorite containing high titanium magnetite. The latter type also contains substantial quantities of phosphate. These two ore types are separately crushed and are kept separate through copper flotation and magnetic separation, for recovery of magnetite, with the low Ti magnetite being shipped as iron ore. High phosphate tailings are pumped to Foskor, a government-owned phosphate plant nearby. The Palabora plant was originally designed in 1966 for 33, 000 tpd using two 54 in. by 74 in. Allis -Chalmers gyratories; two 7 ft (2. 13 m) standards; four 7 ft shortheads; and six grinding lines, each using one 1,200 hp rod mill and two 1,200 hp ball mills. A fifth short- head and one more grinding line were added later; and with flowsheet improvements, the capacity of the plant was increased to 59, 500 stpd. A further plant expansion involving a third 54 in. primary and two 32 ft by 15 ft (9.75 by 4.6 m) 9,000 hp autogenous mills and another flotation section will bring its capacity to 87,500 stpd in 1977. These two fully autogenous mills are constructed entirely out of doors near the primary crusher, and the ground ore will be pumped a mile to the concentrator by a five-stage pumping system. The Palabora ore is mined with 6, 10, and 12 7d (4.6, 7.6, and 9. 2 cu m) shovels and hauled to the crushers in 110 and 165 st trucks. Sixty-five ton trucks were originally used, but the crusher dump pockets were designed for larger units. Dump pockets, crushers, feeders, and take- away belts are offset in order to keep the two ore types separate. Centerlines of the crushers are only 43 ft (13. 1 m) apart; but, because of their being offset, maintenance room is ample. Initially, more carbonatite ore than foskorite was mined; but as the pit has deepened, this ratio has been reversed. The Palabora ore breaks in the pit with a large amount of oversize boulders; and, with the use of larger trucks, a splitter has been installed on one side of each dump pocket to protect the crusher spider. Smaller trucks dump on the opposite side. To accomodate the splitter, the pocket edge has been raised one meter and moved back one meter. Dust is collected through a special vent shaft between the crushers and the mantle relining area; but even so, two high-pressure water spray headers with nozzles are installed under the edge of the pocket at each dumping position. While only one truck dumps at a time, sprays from all four headers are used to suppress dust. Any leakage of water through the seal around the upper bowl of the crusher is caught by a circular trough under the seal and directed to a sump pump. At this point, there

Jan 1, 1978

By J. M. Lovejoy

Various estimates have been made as 60 the percentage of oil left in a field after the wells have become so small that it is no longer practical to produce them. Engineers have given the matter much study and can substantiate their figures by data taken from fields from the Appalachians to California. The average oil sand has a porosity of about 20 per cent., which gives a capacity per acre-foot of approximately 1500 bbl. The sand thickness in Oklahoma pools averages 20 ft. With 20 per cent, porosity and a 20-ft. sand thickness, the capacity per acre is 30,000 bbl., yet these pools will seldom yield more than 5000 bbl. to the acre. These figures gupport the theory that at least 50 per cent. of the oil remains in a sand after all known methods to recover it have been used. Certainly we can never recover all the oil, unless in years to come oil becomes so rare and yet so necessary that the price will justify sinking shafts into the abandoned fields and regular mining methods of drifting and stoping. However, with improved methods of production and conservation of the natural agencies of expulsion, we should be able to increase recovery. It is with this in mind that this paper, relating to the effect of back pressure on wells, is presented. Except in the fields where production is caused by hydrostatic pressure, the chief agency for getting oil out of the sand into the hole is the gas that occurs with the oil. After the pressure has declined, probably gravity also is a factor, but not an important one. With a given amount of oil in a sand and a given amount of gas occurring with the oil, the ratio of gas volume per barrel of oil is the key to the ultimate recovery from that sand. Our efforts should be along lines that will lower this ratio and make the gas, the agency given us by nature, do its work better and yield more of the oil, of which it is a part. T. E. Swigart,' of the U. S. Bureau of Mines, has published an extract of the paper he is preparing under the title "The Effect of Back Pressures. on Wells." The experiments described were made on two

Jan 1, 1924

By J. Chipman, H. A. Wriedt

DURING the past twenty years, a considerable background of knowledge has been built up on the chemical behavior of oxygen in liquid iron. Little is known regarding oxygen in liquid nickel or the effect of nickel as an alloying element on the behavior of oxygen in liquid steel. The solubility of oxygen in liquid iron was determined by Fetters and Chipman' and, more precisely, by Taylor and Chipman.' The Ni-NiO eutectic was placed by Merica and Waltenberg"' * at 1438°C and 0.24 pct 0, and this point has been confirmed by others." O It was reported by von Bohlen und Halbach and LeitgebelT that nickel and its oxide are miscible in all proportions at 1600°C, but this report is discredited by observations of others. The melting point of NiO according to von Wartenberg and ReuschV s 1990°C. Approximate values of oxygen solubility at several temperatures were reported by Hensel and Sc0tt.O The data of Krupowski and Balickil0 are inconsistent with those of Hensel and Scott and indicate a solubility less than half that found in the present study. For oxygen solubility in Fe-Ni alloys under pure iron oxide-nickel oxide slags, only the scattered data of von Bohlen und Halbach and LeitgebelT are avail- able. The careful work of Bardenheuer and Brauns" involved silica-saturated slags. The equilibrium between Fe-Ni alloys and iron oxide-nickel oxide slags was studied by zur Strassenu and by Jander and Senf,u but no oxygen analyses were reported. Oxygen in Pure Nickel Apparatus and Nlethod: Samples were taken with a "Taylor sampler" from a bath of molten electrolytic nickel held under an air atmosphere in a magnesia-lined 30 lb induction furnace. Saturation of the melt with oxygen was effected partly by the addition of chemically pure black nickel oxide and partly by the air atmosphere. Samples were taken only when there was a clearly visible oxide phase present. To avoid contamination of this oxide phase, the silica-sheathed Pt—Pt-10 pct Rh thermocouples, by means of which temperatures were measured, were immersed in the melt for the minimum time consistent with accurate reading. Samples and temperature readings were taken only after the furnace had been

Jan 1, 1956

By Burton Atkinson, David Johnston

Evaluation of Ellenburger reservoirs in West Texas has been an uncertain matker at best because of the lack of cores and suitable core-analysis method. Large amounts of oil arc produced from sections from which sample cuttings are obtained that contain litile porosity and no oil saturation. It has long been realized that the formation in some areas contained numerous fractures and solulion cavities that probably contained the major part of the oil present but the magnitude of the porous system conltaining oil has been unknown. Diamond coring cquipmene, used in the mining industry lor many years, has been developed for oil-field use to obtain high core recovery in fractured dolomite that is not possible with conventional coring equipment. A 36ft section of the core recovered from a fractured Ellenburger reseivoir waS analyzed by a unique but simple method to obtain the first defmite evaluation of one section of the producing formation. The cores and the method of analysis used are described and the results arc discussed in some detail. Discussion The first successful known analyses of cores recovered from the Ellenburger formation in the Permian Basin area were made on cores recovered with the use of diamond core heads. Conventionul coring methods previously used have had lour core recovery and standard methods of analysis have proved to be inadequate for evaluation of those cores that were recovered. Core Descriplion The Ellenburger formation to be dis cussed was cored using diamond core heads and oil-base drilling fluid. Of the total 103 ft cored to a depth of 8893 ft in the Ellenburger, 99 ft or 96 pct was recovered. The dolomite cores were described as gray to white, crystalline to coarscIy crystalline, with chert and calcite inclusions. Occasional shale partings ? to ¼ in. in width were noted. A small amount of green clay was found in some of the coarsely crystalline material. So intergranular porosity was found by inspection in any of the cores. The core urns highly fractured over most of its length with not more than two continuous feet that failed to contain fractures. The fractures Were nearly vertical and varied in width from those harely visible to as much as one millimeter. Scattered solution voids, or vugs, as large as 3 cm in diameter occurred in association with same •a

Jan 1, 1949

By Valentin R. Garfias

The production of petroleum in the Mexican fields during 1931 followed the downward trend of the past nine years, with a decline of close to 6,600,000 bbl., or about 17 per cent from the 1930 total. The output was close to 32,964,000 bbl., the Tampico-Tuxpam fields showing the largest actual and proportional decline, while the production of the fields in the Isthmus of Tehuantepec remained practically unchanged. Wildcatting along the international border was carried on more actively than in previous years, the only successful completion being the Alberca No. 1 well located about eight miles from the international boundary, across from Roma, Tex. This well, completed at a depth of 2015 ft. and plugged back to 1550, is rated at about 6,000,000 cu. ft. of gas per day from a horizon between 1330 to 1540 ft., and is now connected to the gas line from the Jennings gas field, Texas, supplying the city of Monterrey. Favorable oil indications have been encountered in other exploratory wells along the border and drilling will probably continue as these lands are largely held under government concessions which require continuous development work in order to retain title. Development in the Isthmus of Tehuantepec has progressed in a systematic manner, the number of successful completions during the year being considerably larger than in the South or Northern fields. The oil pipe line from the south fields to Mexico City has been completed and its operation and that of the Azcapotzalco refinery is expected to begin early in 1932. The construction of this line will Tevolutionize the transportation of petroleum and its products from the fields to the high plateau and seriously affect the revenues of the government-owned railroads. General conditions in the oil industry were reflected in Mexican operations. Low prices and the imminent threat of an American oil tariff discouraged development work necessary to maintain or increase production, and the curtailment of activities resulted in considerable reductions in personnel by all companies. Early in 1932 the Mexican Government announced its intention to create a surface tax or yearly rental on oil lands equivalent to about 31/4 U. S. cents per acre. Such additional burden on this already harassed industry will not only create little or no

Jan 1, 1932

By K. L. Moazed, G. M. Pound

An investigation was made of the deposition of silver from a thermal beam onto tungsten field-emitter tips at 300°K. "Island"-type nuclei were observed to form and grow. The nucleation of silver crystals occurs preferentially on non-close -packed planes of a tungsten tip at a critical volume free-energy change of about —2900 cal per cc. The adatom population which is critical for appreciable nucleation rate of silver crystals is about 0.2 of a monolayer and is essentially independent of beam flux, time, and source temperature. This result is strong evidence that a metastable equilibrium exists between adatoms and critical nuclei, as assumed in the present theory. SOME of the more significant studies of nucleation in deposition of metals from vapor beams have been conducted by measuring the thermal beam flux which is critical for appreciable rate of nucleation on a substrate surface held at a given temperature.'2 The observed critical supersaturations may be described in terms of Eq. [7] which was derived3'3a on the model of an adsorption, surface migration, and statistical fluctuation mechanism. However there usually made with a low-power optical microscope, a fairly insensitive method of detection. The object of the present study was to overcome some of these difficulties by measuring the critical supersaturation for condensation of a thermal beam of silver onto a tungsten field-emitter tip. Such a tip may be cleaned by electrically heating it to a high temperature in situ, and the high vacuum obtainable in a field-emission tube (10-10 torr) precludes adsorption of residual gases for convenient periods of time. Furthermore, the degree of cleanliness, the orientation, and the state of imperfection of the tip may be ascertained from the field-emission pattern. Detailed explanations of theoretical considerations and experimental procedures relating to the field-emission microscope may be found in a number of excellent review articles12'13 and thus only a brief description will be given here. The electronic work function of a metal is defined as the energy that an electron needs to escape from the potential field of the solid. By applying a large field between the surface of the solid and a suitable collector, it is possible to free the electrons by the tunnel effect. Fields of approximately 30 million v per cm are needed to produce this effect, and such fields are obtained in practice by using microscopic surfaces of high curvature (tips). Because the work function of a metal is a function of surface orientation, the emission from the various planes is different, and thus it is possible to obtain a representation of the surface in the emission microscope. In general, the work function is higher for the more densely packed planes. Fig. 1 shows a pattern for "clean" tungsten in which the central dark region represents the (110)

Jan 1, 1964

By F. C. Miller

The metallurgical fuel of Colorado, Utah, and New Mexico has been a Veiny tardy member in the caravan of western industrial progress. The history of western coke has naturally been closely related to the development of the metallurgy of iron and steel and the precious metals, in the State of Colorado. It was at Leadville, with a population of 300 in 1877, that the Sentinel was published by Richard S. Allen. The Sentinel gave very full accounts of the various mineral discoveries at the new town of Leadville, which found their way to the more widely circulated journals of the East, and attracted the attention of many people. At the close of 1878, a census slowed a total of 5040 persons. The first smelter was established in 1877, at Malta, two miles from Leadville, by A. R. Meyer, but was not successful. It was succeeded by the Harrison Reduction Works, in 1878. The La Plata began with one furnace in June, 1878, and in 1879 had four furnaces in active operation. These furnaces used charcoal for fuel, and, because of hot tops, suffered a tremendous loss in lead and silver. This difficulty was overcome by the erection of 50 single-bank 10-ft. beehive ovens at Crested Butte, Colo., in 1880. The slack coal sent to these ovens was very pure, and yielded a coke carrying as little as 4.5 per cent. ash. Among the pioneers in the Leadville district were Grant, Eddy, James, Billings, Eiler, and Dickson. To these men the West owes the present expansion of its mining industry, and the erection of metallurgical processes for the treatment of precious metals. On Mar. 1, 1876, Pueblo was connected to the Atchison, Topeka & Sank Fe by the Pueblo & Arkansas Valley branch. The first smelter was erected in Pueblo by Mather and Geist. This modest plant grew into the immense Pueblo Smelting and Refining Co., now a part of the American Smelting and Refining Co. Coke for these small furnaces was made from unwashed Engleville coal, in 186 single-bank 12-ft. ovens at El Moro, in the Trinidad district, and it was not uncommon for the percentage of ash to exceed the percentage of fixed carbon in the coke. On Jan. 23, 1880, the Colorado Improvement Co. consolidated

Jan 1, 1920

By Harry H. Angst

THE history and efficiency of 40-ton capacity dump trucks for surface waste removal at the New Cornelia opencut copper mine, at Ajo, Ariz., are summed up in this paper. Tabulations of truck performance, together with detailed cost figures, prove the value of truck transportation for certain special operations at a large mine. Emphasis is given to the fact that truck transportation not only reduces the haulage costs but also reduces the breaking ground and shovel-loading costs per ton. The New Cornelia opencut copper mine is in the desert. The climate is ideal for seven months of the year, but the five summer months are uncomfortably hot. The elevation is 1820 ft. above sea level and the annual rainfall is approximately 6 inches. The ore body is a monzonite-porphyry deposit. The waste-rock capping consists of hard rhyolite, conglomerate and porphyry. All the material is hard and cannot be excavated without blasting. The rhyolite and conglomerate waste is very blocky. The weight of the rock in place is 2.16 tons per cubic yard. The average mine production per day is 22,000 tons of ore and 18,000 tons of waste rock, the latter consisting of surface rock and material within the ore body too low in grade to send to the concentrator. The rock is loaded by electric shovels with 4 ½ -cu. yd. dippers. The primary transportation of ore to the concentrator and waste to the dumps is by 30-yd. dump cars and oil-burning steam locomotives; therefore truck haulage of waste is a minor factor of the New Cornelia operation. However, as New Cornelia was one of the first mines to use large-capacity dump trucks for haulage, the results obtained are of interest. EQUIPMENT On the south side of the New Cornelia is a hill rising about 500 ft. above the normal surface elevation, roughly 1000 ft. in diameter at its base, called locally Arkansas Mountain peak. Exploratory drilling in this area developed additional ore that could be made accessible for open pit operation only by moving the mountain face a maximum distance of 400 ft. to the south. The slope of the mountain adjacent to the pit averaged 35°, and the small area involved precluded the use of train haulage for the removal of the 4,000,000 tons of waste estimated above the normal pit elevation. A study of dump-truck haulage at Boulder Dam and San Gabriel Dam led to the decision to use large-capacity end-dump trucks rather than smaller trucks, for the following reasons: 1. The truck would have to withstand the impact of hard, heavy chunks, some of them weighing as much as 10 tons, which would be dumped from the 4 ½ -cu. yd. dipper. 2. The coarse, rocky, abrasive material would soon damage a light truck body. 3. The body of a small truck could not be efficiently loaded with coarse rock.

Jan 1, 1941

By E.G. Lewis, l.M. Barker

The literature of milling is replete with papers devoted to the subject of ball milling, all of which no doubt have contributed in one way or another to progress in that art. In this paper reference will be made to only a few of the many authors, but the value of the contributions of all who have written on that subject is hereby acknowledged. With a few exceptions the efforts of most students of the subject have been devoted to laboratory investigations of principles. Davis1 was one of the first to report on plant-scale investigations and to present to mill men certain criteria for the guidance of ball-milling practices. His conclusions with respect to the significance of sizing analyses of classifier sands in their relation to the factors of mill speed and ball sizing are particularly referred to. Those conclusions were: 1. If the balls are large or the speed of the mill is high, crowding will appear at the finer sizes in the classifier sands. 2. If the balls are small or the speed is low, crowding will appear at the coarser sizes in the classifier sands. 3. The indications are that best efficiency is obtained when the screen analysis of the sands show a minimum crowding at any size. The last conclusion was qualified by the statement that it had not been proved conclusively. It is surprising, however, that the litera- ture of later years reveals little evidence that millmen have made any serious attempt to apply those criteria. This may, perhaps, be explained by the fact that the average plant-scale ball-milling problem presents so many variables that an investigation of any one of them encounters the problem of control of the others—a problem that often is unsurmountable in a small plant. In a large plant, in which there is a duplication of grinding units in parallel operation, opportunity may be afforded for determining the value of such criteria. Nevertheless, a study of published data from grinding circuits of both large and small plants suggests that either Davis' criteria have been tried and found inapplicable or have never been given consideration. For the purpose of testing Davis' conclusions and with improvement of ball-milling efficiency as the final objective, a test program was initiated in the concentrator of the New Cornelia branch of the Phelps Dodge Corporation early in 1938. The practices of that plant have already been described.2 The fine-grinding units are arranged so that any one of eight units may be operated as a test unit and its results compared with those of the remaining units. All units receive similar feed from a common storage bin, in which the product of the fine-crushing plant is bedded by traveling tripper. The ball mills are all similar in size and operated at the same speeds, and are individually metered. The feeder conveyors of each unit are equipped with Merrick weightometers. The test program as initially outlined proposed investigation of the following:

Jan 1, 1943

By L. M. Barker, E. G. Lewis

The literature of milling is replete with papers devoted to the subject of ball milling, all of which no doubt have contributed in one way or another to progress in that art. In this paper reference will be made to only a few of the many authors, but the value of the contributions of all who have written on that subject is hereby acknowledged. With a few exceptions the efforts of most students of the subject have been devoted to laboratory investigations of principles. Davis1 was one of the first to report on plant-scale investigations and to present to mill men certain criteria for the guidance of ball-milling practices. His conclusions with respect to the significance of sizing analyses of classifier sands in their relation to the factors of mill speed and ball sizing are particularly referred to. Those conclusions were: 1. If the balls are large or the speed of the mill is high, crowding will appear at the finer sizes in the classifier sands. 2. If the balls are small or the speed is low, crowding will appear at the coarser sizes in the classifier sands. 3. The indications are that best efficiency is obtained when the screen analysis of the sands show a minimum crowding at any size. The last conclusion was qualified by the statement that it had not been proved conclusively. It is surprising, however, that the litera- ture of later years reveals little evidence that millmen have made any serious attempt to apply those criteria. This may, perhaps, be explained by the fact that the average plant-scale ball-milling problem presents so many variables that an investigation of any one of them encounters the problem of control of the others—a problem that often is unsurmountable in a small plant. In a large plant, in which there is a duplication of grinding units in parallel operation, opportunity may be afforded for determining the value of such criteria. Nevertheless, a study of published data from grinding circuits of both large and small plants suggests that either Davis' criteria have been tried and found inapplicable or have never been given consideration. For the purpose of testing Davis' conclusions and with improvement of ball-milling efficiency as the final objective, a test program was initiated in the concentrator of the New Cornelia branch of the Phelps Dodge Corporation early in 1938. The practices of that plant have already been described.2 The fine-grinding units are arranged so that any one of eight units may be operated as a test unit and its results compared with those of the remaining units. All units receive similar feed from a common storage bin, in which the product of the fine-crushing plant is bedded by traveling tripper. The ball mills are all similar in size and operated at the same speeds, and are individually metered. The feeder conveyors of each unit are equipped with Merrick weightometers. The test program as initially outlined proposed investigation of the following:

Jan 1, 1943

By Ralph E. Esarey, G. F. Fix

The oil and gas industry in Indiana in 1938 showed considerable improvement over the preceding year. Most of the drilling and development during the year, as in the past several years, was in the Indiana portion of the Illinois Basin, but increasing interest was apparent in the old Trenton area, for possibilities of further production in the Trenton formation and the underlying St. Peter sandstone. Interest in all other portions of the state was at a new peak, since many areas have never been prospected. Natural gas production continued to drop during 1938, since new discoveries have not been able to keep pace with the rapid decline in older areas. Oil production increased considerably, chiefly through the discovery of new fields. Older fields contributed about the same quantity of oil during 1938 as during the preceding year. There were 159 wells completed in Indiana during 1938, an increase of 25 over the preceding year. Of these, 48 were oil wells, 41 were gas, and '70 failed to find commercial production. Forty-three, or about 20 per cent, were wildcat. Six of these were productive—three oil wells and three gas wells. Thirty-nine wells on which operations started during the year had riot been completed by Dec. 31. Fourteen others were temporarily abandoned, with the possibility that several will be drilled to completion in the near future. A new oil field (Heusler) was discovered in May 1938, in sees. 1 and 12, T. 7 S., R. 12 W., Posey County. Production was found in the Waltersburg (Upper (Chester) sandstone at a depth of approximately 1775 ft. At the close of the year, Heusler field had nine producing wells and two drilling. The Point township area, Posey County, near the confluence of the Wabash and Ohio Rivers, held promise of good production from the McClosky lime, but offsets to the, discovery well had only shows of oil. The discovery well declined rapidly in production arid was finally plugged. In the Oaktown field, Knox County, a wildcat came in with a good flow of gas, extending the field to the east, and proving considerably more acreage. A new gas area was discovered in Sullivan County, and four good wells were completed. The discovery well was in sec. 35, T. 8 N., R. 10 W., and had an initial

Jan 1, 1939

By Ralph E. Esarey, G. F. Fix

The oil and gas industry in Indiana in 1938 showed considerable improvement over the preceding year. Most of the drilling and development during the year, as in the past several years, was in the Indiana portion of the Illinois Basin, but increasing interest was apparent in the old Trenton area, for possibilities of further production in the Trenton formation and the underlying St. Peter sandstone. Interest in all other portions of the state was at a new peak, since many areas have never been prospected. Natural gas production continued to drop during 1938, since new discoveries have not been able to keep pace with the rapid decline in older areas. Oil production increased considerably, chiefly through the discovery of new fields. Older fields contributed about the same quantity of oil during 1938 as during the preceding year. There were 159 wells completed in Indiana during 1938, an increase of 25 over the preceding year. Of these, 48 were oil wells, 41 were gas, and '70 failed to find commercial production. Forty-three, or about 20 per cent, were wildcat. Six of these were productive—three oil wells and three gas wells. Thirty-nine wells on which operations started during the year had riot been completed by Dec. 31. Fourteen others were temporarily abandoned, with the possibility that several will be drilled to completion in the near future. A new oil field (Heusler) was discovered in May 1938, in sees. 1 and 12, T. 7 S., R. 12 W., Posey County. Production was found in the Waltersburg (Upper (Chester) sandstone at a depth of approximately 1775 ft. At the close of the year, Heusler field had nine producing wells and two drilling. The Point township area, Posey County, near the confluence of the Wabash and Ohio Rivers, held promise of good production from the McClosky lime, but offsets to the, discovery well had only shows of oil. The discovery well declined rapidly in production arid was finally plugged. In the Oaktown field, Knox County, a wildcat came in with a good flow of gas, extending the field to the east, and proving considerably more acreage. A new gas area was discovered in Sullivan County, and four good wells were completed. The discovery well was in sec. 35, T. 8 N., R. 10 W., and had an initial

Jan 1, 1939

By John Jan

Iodine is a soft, lustrous, grayish-black non- metallic element with a density of 4.9. It is the least active of the four members of the halogen family. The other members are, in order of increasing activity, bromine, chlorine, and fluorine. Iodine is a solid at ordinary temperatures, while bromine is a liquid and chlorine and fluorine are gases. Iodine melts at 113°C and volatilizes at 184.4°C to a blue- violet gas with an irritating odor. It occurs in nature only as iodates and iodides or other combined forms. It was discovered by Bernard Courtois in France in 1811, who noticed its presence as an unknown substance in crude soda ash obtained from burning seaweed. Gay-Lussac recognized it as a new element and named it iode, from the Greek word "ioeides or iodes" for violet color (MacMillan, 1970). The world production is not known with any great certainty, but it is probably between 20 and 25 million lb per year, of which about 25% is consumed in the United States. Geology and Mineralogy Iodine compounds occur as a minor constituent as a mineral in the Chilean nitrate deposits and in solution in brines and sea- water. According to the U.S. Geological Survey, it is the 47th most abundant element in the earth's crust. The minerals lautarite, Ca (10,) (calcium iodate), and dietzeite, Ca, (10,) , (CrO,) , (calcium iodate-chromate) are found in Chilean nitrate deposits which are located in Antofagasta and Tarapach provinces on the eastern slope of the coast range in a desert area. Various brines contain iodine compounds. Seawater contains about 0.05 ppm of iodine and some seaweeds will extract and accumulate it up to 0.45% on a dry basis. Some coals in West Germany also contain iodine compounds. The known and potential sources of iodine reported in 1968 are given in [Table 1]. Iodine has been recovered from brines in Java, Indonesia, France, England, and the USSR. Iodine has also been recovered from seaweed in Ireland, Scotland, France, Japan, Norway, and the USSR. The indicated re- serves and future resources of iodine are large but have never been adequately measured. Analysis Iodine as the free element can be detected by the characteristic blue color it gives to a starch solution. Quantitatively it is determined as the free element by titration with standard thiosulfate solutions using starch as an indicator. Colorimetric methods are also applicable.

Jan 1, 1975