Search Documents

By Perry Olcott .

THE Taka oil field is in the northern part of Titus and Franklin Counties, in north- eastern Texas. The small town of Talco, from which the field derives its name, is on the P. & Mt. P. R. R., about 15 mi. north of Mt. Pleasant, the county seat of Titus County. The oil field extends east and west from the town of Talco, the approximate center. In May, 1924, R. L. Cannon, while doing surface geology for the Humble. Oil & Refining Co., mapped the surface trace of this fault structure as evidenced by Upper Midway faulted down against Lower Midway. In the interval of sixteen years between the original surface work and the recent productive well completion, approximately eight wells were drilled into the Woodbine sand without success. The structure was well defined by those tests and all of the wells en-

Jan 1, 1936

By W. B. Lewis, M. E. True, M. C. Leverett

Tars paper states the theory underlying the design of two kinds of dimensionally scaled models of parts of idealized oil fields. One of these simulates an oil well and its surrounding sand for a distance of 16 ft. radially from the well. The other model simulates linear flow through layered sands. Construction and operation of the models are described and typical data are given. The unique features in the design of the models are: (I) the treatment of the permeability-viscosity quotient as a single variable and (2) the use of previously reported experimentally developed relations between relative permeability and saturation and capillary pressure, saturation, porosity, perm ability and interfacial tension. The models at present simulate flow of oil and water only, through unconsolidated sands. They are superior to unscaled models, which may give rise to erroneous conclusions. The models are designed to study the desirability of various methods of sell completion and the effects of various factors on recovery of oil from layered sands.

Jan 1, 1942

By P. W. George, G. A. Hellstrand

In 1915, H. A. Guess, Vice President of American Smelting & Refining Co., in charge of its Mining Department, learned that the Anglo-Newfoundland Development Co., Ltd., a pulpwood and paper-mill enterprise, had found upon its large concession in Newfoundland, and had opened up by shaft to the third level and some drifting, a lenticular orebody indicating about 100,000 tons, as an extremely fine-grained sulfide ore, averaging about 0.05 oz. Au, 4 oz. Ag, 1.5 per cent Cu, 10 per cent Pb, 18 per cent Zn; and that having sent parcels of this ore to Minerals Separation, Ltd., and various other metallurgical testing concerns without obtaining any success in commercial separations thereof, had discontinued work thereon and let the workings fill. Mr. Guess wrote to the general manager of that company and obtained a few hundred pounds of the typical ore, which he sent to his company's metallurgical testing laboratory at Flat River, Mo., outlining various flotation tests desired thereon, in an endeavor to obtain separation into a commercial lead concentrate and a zinc concentrate. But the art of flotation had not then progressed far enough to treat such ore, the galena and zinc blende being so fine grained that grinding to about 300 mesh was required to release the mineral particles in their gangue. Mr. Guess had flotation and other tests continued upon this ore from time to time with whatever new reagents and flotation devices were evolved as time went on, and finally, in 1925, he succeeded in effecting in his company's testing plant, then at Wallace, Idaho, separations into lead concentrates and zinc concentrates of satisfactory commercial grade. Mr. Guess then proceeded to unwater, examine and sample the property and made with the owners a partnership operating agreement upon the mine itself and a considerable area surrounding it, and in the early summer of 1926 began to prospect for additional orebodies, utilizing for such prospecting geophysical methods under the direction of Hans Lundberg, methods which up to that time had been little used in mining in the western hemisphere. This geophysical work found two large flat-lying orebodies of a type precisely similar to the smaller body of the original discovery. The larger orebody, some 3500 ft. west of the original

Jan 1, 1935

By T. Sterry Hunt

The deposit of rock-salt which is known to exist along the eastern shore of Lake Huron, in the province of Ontario, has lately been more completely explored than before, by a boring with a diamond drill, put down by Henry Attrill, Esq., of New York City, and the results obtained are so important in every way that I make no apology for presenting them to the Institute of Mining Engineers. I may be permitted to preface an account of this remarkable exploration, and of its results, with a historical sketch of the discovery and development of this salt-region. It was in December, 1865, that a boring was begun near the town of Goderich, in the hope of finding petroleum. In this the adventurers were disappointed, but, after passing through about 800 feet of limestone, they encountered a series of variegated marls, in which, at a, depth of 964 feet from the surface, a bed of rock-salt, 30 feet in thickness, was met with in May, 1866. The boring was carried to a depth of 1010 feet, ending in hard rock, and yielded, by pumping, a very pure saturated brine when examined by me in August of the same year. In the report of the Geological Survey of Canada for 1863-66, published early in 1867, I described this salt-well, with many geological details, and gave an analysis of the brine. In the next three years a considerable number of wells was sunk in and around Goderich, and numerous trials were made in various other parts of the region. Salt was found at Kincardine, thirty miles north-northeast from Goderich, at a depth of about 900 feet, and also at Clinton, thirteen miles southeast, at 1180 feet. Records of these wells, with analyses of the brine from them, were given by myself in a subsequent report of the Geological Survey, 1866-69, published in 1870 (pp. 211-244), together with accounts of various unsuccessful borings in the neighborhood, analyses of the brines from the various wells (including one analysis by Dr. Goessmann), with many details of the salt-manufacture at Goderich, at Syracuse, New York, and at Saginaw, Michigan. The geological character of the region was there discussed at length, and it was shown that the salt here occurs in the Onondaga or Salina formation, which

By T. Sterry Hunt

THE deposit of rock-salt which is known to exist along the eastern shore of Lake Huron, in the province of Ontario, has lately been more completely explored than before, by a boring with a diamond drill, put down by Henry Attrill, Esq., of New York City, and the results obtained are so important in every way that I make no apology for presenting them to the Institute of Mining Engineers. I may be permitted to preface an account of this remarkable exploration, and of its results, with a historical sketch of the discovery and development of this salt-region. It was in December, 1865, that a boring was begun near the town of Goderich, in the hope of finding petroleum. In this the adventurers were disappointed, but, after passing through about 800 feet of limestone, they encountered a series of variegated marls, in which, at a, depth of 964 feet from the surface, a bed of rock-salt, 30 feet in thickness, was met with in May, 1866. The boring was carried to a depth of 1010 feet, ending in hard rock, and yielded, by pumping, a very pure saturated brine when examined by me in August of the same year. In the report of the Geological Survey of Canada for 1863-66, published early in 1867, I described this salt-well, with many geological details, and gave an analysis of the brine. In the next three years a considerable number of wells was sunk in and around Goderich, and numerous trials were made in various other parts of the region. Salt was found at Kincardine, thirty miles north-northeast from Goderich, at a depth of about 900 feet, and also at Clinton, thirteen miles southeast, at 1180 feet. Records of these wells, with analyses of the brine from them, were given by myself in a subsequent report of the Geological Survey, 1866-69, published in 1870 (pp. 211-244), together with accounts of various unsuccessful borings in the neighborhood, analyses of the brines from the various wells (including one analysis by Dr. Goessmann), with many details of the salt-manufacture at Goderich, at Syracuse, New York, and at Saginaw, Michigan. The geological character of the region was there discussed at length, and it was shown that the salt here occurs in the Onondaga or Salina formation, which

Jan 1, 1877

By A. D. Brokaw

The so-called "paraffin dirt" of the Gulf Coast oil fields has been considered an indication of the possible presence of oil and gas, and not a few wells have been brought in solely on the basis of such evidence. In a sense, it may be empirically justified as evidence of the presence of oil or gas, though it cannot be said to be infallible. If the writer is correctly informed, its association with oil and gas was pointed out by Lee Hager some years ago, and while it is commonly mentioned by geologists and operators in conversation, no discussion seems to have found its way into print. The present interpretation is based on laboratory study rather than on field investigation, and is put forth with the hope of stimulating discussion which shall lead to more complete understanding. The term "paraffin dirt" has been applied to soils with a peculiar texture, which has been described as "curdy" or "rubbery." When moist, the material breaks much after the fashion of "green" cheese. It is rubbery under compression, but does not resemble rubber in tenacity or cohesion. When dry, the material ranges from hard clods to a horny mass of high tensile strength. The shrinkage in drying is very great, especially in the hornlike matter. The moist material ranges in color from dark brown in the specimens rich in organic matter to grayish in specimens containing more inorganic matter. All of the specimens studied were readily attacked by molds, which in some cases grew in great profusion on the samples. Samples exhibited a rather characteristic "swampy" or "mucky" odor when wet, and a characteristic odor of humic soils when moist. If the material is brought into suspension in water, very fine sand settles out and may be recovered by successive washing and decantation. The sand is almost entirely quartz, but contains occasional fragments of feldspar—more or less kaolinized and iron-stained. Practically all of the sand passes through a 100-mesh screen and the grains are extremely sharp —possibly below the limit of rounding. A flocculent mud, of clay and organic matter, remains in suspension for days. Some material is taken into solution in the water, imparting a slight tendency to froth when vigorously shaken. The results of partial analyses of four samples of "paraffin dirt," and, for comparison, one of a coastal plain soil are given in Table I.

Jan 1, 1920

By J. M. Dumore

If in a vertical, downward miscible displacement, the transition zone between the displacing and displaced fluids is neglected, a criterion for stable displacement can be obtained by considering a small hypothetical protrusion of one of the fluids into the other. This criterion leads to the definition of the well-known critical rate, uc = kg p/p. The consideration is further extended by taking into account the transition zone that develops as a result of diffusion and mixing. A generalization of the previous criterion leads to the definition of another characteristic rate, the stable rate, which in actual miscible drives will be less than the critical rate. In such drives, the entire transition zone is stable at rates less than the stable rate. At rates between the stable and critical rates, the displacement is only partly stable, i.e. part of the transition zone adjacent to the displaced fluid is in an unstable position. From that part of the transition zone viscous lingers will develop. At rates greater than the critical rate the entire displacement is unstable and viscous lingers will develop more strongly. Results of laboratory experiments are in agreement with the expected behavior based on the theoretically deduced stability of the displacement. INTRODUCTION The simplest form of miscible drive in an oil-bearing formation is the injection of a fluid that is completely miscible* with the oil under reservoir conditions. In general, such a fluid, a solvent for example, is less dense and less viscous than the oil present in the formation. If it is injected into a horizontal homogeneous layer, gravitational forces will lead to the formation of a gravity tongue of solvent in the upper part of the layer and the adverse solvent-oil viscosity ratio will cause viscous fingers to develop. If, however, the solvent is injected up-structure into ,a dipping layer, gravity has a favorable effect, because it tends to keep the less dense solvent up-structure. Tongue formation and viscous fingering are consequently reduced and it is even possible that they will be suppressed completely. Viscous fingering and gravity tonguing are the consequences of the instability of the displacement. A stable displacement cannot result in growing viscous fingers and/or growing gravity tongues. Since large amounts of oil can be bypassed if there is viscous fingering and/or gravity tonguing, the stability of a miscible drive is very important with respect to the recovery efficiency of the drive. The stability is of particular importance in miscible-slug drives, as it determines how quickly the miscible slug between the displaced and displacing fluids will be distorted and broken up, after which the drive is no longer completely miscible. Stability is thus a most important factor in determining the success of a miscible drive, and it is considered that the aspects of stability considered in this paper will make a useful contribution to existing theories. Consideration is given only to vertical downward displacements, in which no gravity tongues can develop and which are therefore simpler than downward displacements in sloping layers. THEORY CRITERION FOR STABLE DISPLACEMENT Let us consider a vertical column of a homogeneous permeable medium saturated with oil. A solvent less dense and less viscous than the oil is injected at the top of the column at a constant rate; in the column the velocities of oil and solvent are assumed to be uniform. Diffusion and mixing of oil and solvent will at first be neglected, i.e. we assume that solvent and oil are divided by a sharp interface. An additional assumption is that the interface is horizontal. Continuity of pressures exists at the interface, because no capillary forces are present between the two miscible fluids. Consequently, at the interface (Z = I)):** Ps = Po - P-where Ps is the pressure at the solvent side and

Jan 1, 1965

By N. L. Carwile, G. W. Geil

A metallographic study was made of deformation twinning (Neumann lamellae) in ingot iron slowly deformed in tension at —196O and —150°C. The results showed that twinning is initiated mainly during the initial stages of plastic deformation. However, the breadth of the twins generally increases with increase in strain up to fracture of the specimen. HE results of an investigation of the effect of low I temperatures on the flow, fracture, strain hardening, and strain aging characteristics, and the true stress-strain relationship for specimens of ingot iron deformed in tension were reported recently.1,2 In that study specimens of ingot iron, in different initial conditions, were slowly deformed in tension at various temperatures between —196" and +100°C. A phenomenon observed, but only briefly reported, was the formation of deformation twins (Neumann lamellae) in the specimens deformed at the lower temperatures. Preliminary metallographic examination of these specimens indicated that there was apparently some correlation between the deformation twinning and the strain of the specimen and that this factor merited further investigation. Some recent investigations have indicated a direct association of Neumann lamellae and the fracture of the metal. Bruckner".' * postulated that the twinning immediately precedes the fracture and the latter is initiated by the stopping of the propagation of twins, either at subgrain boundaries or at other structural features. Tipper and Sullivan5 postulated that Neumann lamellae are initiated by the shock or a shock wave set up at fracture in the still highly stressed unbroken metal, and that a high rate of deformation is a necessary condition for their formation. An extensive metallographic examination, therefore, was made of many of the specimens used in the study of ingot iron at this Bureau and of additional specimens deformed to selected strains under various conditions. The present paper summarizes the effects of deformation under these conditions upon the breadth and scope of the deformation twins. Other features of twinning will be discussed in another paper. Material and Testing Procedure All of the specimens were prepared from one lot of ingot iron, as hot-rolled, of chemical composition other than iron as follows: C, 0.02 pct; Mn, 0.02; P, 0.005; S, 0.018; Si, 0.002; Cu, 0.10; 0, 0.058; and N, 0.002. Cylindrical tensile specimens with a 2 in. gage length were used. The reduced section was slightly tapered from each end; the diameter (0.438 in.) at the midsection of the gage length was about 0.003 in. less than at the ends. The specimens were finished to the final dimensions by grinding and polishing in the axial direction. The ends of the specimens were machined with 3/4 in. x 10 threads and the shoulder fillets were machined to a radius of 0.75 in. The specimens were extended slowly in tension (deformation rate less than 0.5 pct reduction in area per minute) while immersed in an appropriate cryogenic liquid maintained at the desired temperature. The minimum diameter of the specimen was measured during the test by means of a specially designed reduction of area gage accurate to 0.0001 in." A detailed description of the testing equipment and the method of maintaining the desired temperature is given in a previous paper.' Each specimen, after deformation to a specified strain at a selected temperature, was sectioned longitudinally and examined metallographically. The preparation of specimens for metallographic examination was carried out in the usual manner by mechanical polishing and etching. Results and Discussion Deformation twins in specimens of ingot iron extended slowly in tension at —196" and —150°C are shown by the representative micrographs of Figs. 1

Jan 1, 1954

By A. E. Deruyttere, J. Van der Planken, M. Laurent, Van den Bergen

FahRENHORST and schmid1 observed that zinc single crystals work hardened less rapidly when strained in liquid air (- 185°C)than in a bath at -82°C, whereas at higher temperatures the rate of work hardening decreased with increasing temperature, as would be expected. Cadmium and magnesium showed no such decrease at -185°C. At that time the observed anomaly for zinc at liquid air temperature probably seemed insignificant. However it later was confirmed2 by experiments in liquid nitrogen (-196°C) and in the mixture solid carbon dioxide-acetone (-77"C) and therefore appeared to be real. seeger3 then suggested that the anomaly might be due to the different wetting of the zinc crystals by the cooling media. Recently a new confirmation was obtained,4 however the cooling media again were different: the rate of strain hardening was found to be lower in liquid nitrogen and liquid oxygen than in pentane cooled to various temperatures down to -126°C. Ekperiments will now be reported in which the medium surrounding the specimen at the different temperatures was the same, namely gaseous air. The single crystals were made from "Overcor 99.99" zinc. They were grown in a vertical traveling furnace on seeds of nearly the same orientations. The diameter of the crystals was 5 mm and the length between shoulders 140 mm. The brass shoulders were stuck to the crystals by means of araldite. A thin steel wire was fixed to each shoulder and served to fasten the specimen to a Houns-field tensile testing machine. The crystals with the shoulders and part of the wires were surrounded by two concentric cylindrical containers. The coolant. either liquid air or ground solid carbon dioxide, was poured into the outer container only. During cooling the containers rested on a support which was removed when the straining was started. In order to check the temperature which the crystals would attain inside the inner container, a hollow bar of zinc in which a thermocouple was fitted was first mounted in the apparatus as a substitute for a crystal. It appeared that a constant temperature, respectively - 183° and -72°C, was attained inside the bar, if a soaking time of the order of 1 hr was allowed and if the outer container was constantly kept filled. Accordingly, this procedure was adopted for every tensile test. To take account of the large scatter, fourteen tensile tests were performed with liquid air and seven with solid carbon dioxide. The orientation of the crystals and the results are presented in the table, in which the symbols have the following meaning: 1 : temperature x : initial angle between basal plane and specimen axis : initial angle between slip direction and specimen axis a : shear strain at fracture 0: average rate of strain hardening = —-——- 100 t0 and Te representing respectively the critical shear stress and the shear stress at fracture. Despite the scatter of the a- and 8— values which is of the same order of magnitude as in the work reported by Seeger and Trzuble,4 it is evident that the strain hardening rate is significantly lower at -183°C thanat-72°C. The table also contains the average values calculated from Seeger and Trauble's results at the corresponding temperatures: z.e., four results at -183oC and two at-70°, -71°C. These authors calculated 9 in a slightly different way, but this is unimportant. The agreement between the a-values shows that both sets of experiments are comparable despite the differences in experimental techniques. The rates of strain hardening also agree and it may therefore be concluded that the anomaly is not

Jan 1, 1962

By C. E. Kemp, A. B. Dyes

Results of a field research project on the thermal recovery of oil by movement of a combustion front are presented. This field test was conducted in the South Belridge field, This The war paitern was a Southsing1e 2.5-acre five-spot pattern in the 700-ft deep Tulare sand. Results of this project indicate the technical feasibility of producing high viscosity, low-grallity crude oils by thermal means. It was demonstrated that heavy oils could be moved rapidly over considerable distances by thermal drive, and that high percentage recoveries of oil could be effected. The bulk of the oil recovery came after arrival of the burning front at a production well. However, rapid corrosion and high-temperature failure of conventional pipe and equipment both below and above surface occurred. Stainless steels gave more satisfectory performance under these conditions than did conventional steels. Oxygen was seldom observed in gas from wells ahead of the burning front, and it appears that the front was continuous throughout the life of the experiment. INTRODUCTION During late 1953 and early 1954, industry-wide attention was focused on the thermal recovery of oil by movement of a combustion front through an oil zone. Two separate Oklahoma field tests were described in publications by Kuhn and Koch, and Grant and Szasz. To obtain basic information needed for making engineering and economic appraisals of commercial recovery of heavy oil by this thermal recovery method, a new field research projecta3,4 was started May 31, 1955. Twelve oil companies contributed to this project with General Petroleum Corp. as operator. Since combustion recovery experiments* with heavy oils in other areas had been conducted in small patterns,"' an important purpose of this test was to determine whether the process could be operated in a pattern of near-commercial well spacing. The south Belridge field, located 30 miles north of Taft, Calif., was chosen because its oil sands are similar to many heavy oil sands which typically have low primary recovery and leave a large amount of oil in place. such fields are not particularly suited for common secondary recovery methods. DESCRIPTION OF TEST SITE The test interval was a Tulare sand at a depth of about 700 ft. Nine test wells were drilled, cored and completed from Oct., 1955, through Jan., 1956. The initial pattern shown on the map, Fig. 1, consisted of an injection well (II)', four producing wells (1P-4P), and four observation wells (IT-4T). An old well (81) was also recompleted for use as an observation well. The area enclosed by the original four production wells was 2.5 acres; the distance from the injection well to each production well was 233 ft. During the combustion period, Well 5P was drilled to replace Well 2P, and Well 6P was drilled to replace Well 3P. The new wells were 25 ft beyond the old production wells along a diagonal from the injection well, and resulted in an increase in pattern area to 2.75 acres. Isopachs are shown in Fig. 1. The average thickness of the oil sand in the test pattern was 30 ft. Fig. 2 presents two cross sections through the test pattern. Oil sand is represented by white and claystone by gray. The dashed lines indicate layers of conglomerate grading to claystone. The sand thickness was fairly uniform throughout the test pattern except in the 1P area. The sand body dips gently from the northwest to southeast, about 3 degrees from horizontal. The sand is unconsoli-dated, and grades from very fine material to pebbles as large as 2 in. in diameter. Table 1 presents the average initial properties of the formation. The in-place porosity of 37 per cent was estimated from the porosity of coke-consolidated cores taken after combustion. Original core analyses data were adjusted to 37 per cent, giving pore volume saturations of 60 per cent oil, 37 per cent water, and 3 per

By S. K. Basu, H. H. Kellogg

THE physical-chemical behavior of the system Pb-S-0 is of prime importance to the understanding of lead smelting processes, yet little accurate information is available on either equilibrium or kinetic behavior in this system. This paper is the first report of a program designed to fill gaps in our knowledge of this system. In the total ternary Pb-S-0, the region of greatest metallurgical interest is that bounded by the compositions Pb-PbS-PbS0,-PbO-Pb. Systems richer in sulfur, or richer in oxygen,* than those essentially pure SO2. This conclusion follows from the fact that all systems are in a highly reduced state, since either PbS or Pb is a constituent of all the equilibria. The content of 02, SO3, S2, S6, S8, and so forth, can be shown to be negligible compared to SO, in all such systems.* corresponding to this region can only be obtained at gas pressures exceeding 1 atm, a condition seldom met in lead smelting practice. Not only is the present study limited to condensed phases within this portion of the total system, but it is limited to temperatures at which all phases are pure solids, except for lead, which is liquid. In this limited system the following seven condensed phases are known to exist: Pb(l), PbS(c), PbO(c), PbSO,(c), PbSO,•PbO(c), PbSO4 • 2PbO(c), and PbSO, -4PbO(c). PbO exists in two crystal modifications,' but only the high-temperature yellow form is considered here. Schenck and co-workers2-4 reported the compound PbSO4 3Pb0 to be stable at high temperature, but the more recent work of Lander,5 and the present work, prove that the tetra-basic sulfate, rather than the tri-basic sulfate is stable. Fig. 1 shows the composition diagram for the binary PbO-PbSO2, based primarily on the work of Lander. In this study the univariant boundaries and invariant points existing among these seven condensed phases and the gas phase have been determined. In a ternary system, the phase rule indicates that an invariant point involves the simultaneous equilibrium of five phases—four condensed phases and the gas phase. A univariant relation involves four phases—three condensed phases and the gas phase. The gas phase in the systems studied is The following stable univariant equilibria between SOz and the condensed phases were identified: (a) PbS + 7PbS04 = 4(PbSO, - PbO) + 4SO2 (b) PbS + l0(PbS04 • PbO) = 7(PbSO4- 2PbO) + 4SO2 (c) PbS + 8(PbSO4 • 2PbO) = 5(PbSO4 . 4PbO) + 4SO2 (d) Pb + PbSO, • 4PbO = 6PbO + SO2 (e) 3PbS + PbSO4 . 4PbO = 8Pb + 4SO2 (f) 3PbS + 16(PbS04 PbO) = 7(PbSO4 . 4PbO)+ 12SO2 (g) 2PbS + PbSO,2PbO = 5Pb + 3SO2 (h) Pb + 3(PbSO4 . 2PbO) = 2(PbSO,. 4PbO) + SO, Of these eight univariant equilibria, five were measured in this work (a, b, c, d, and g) and the behavior of the other three (e, f, and h) was calculated by thermodynamic analysis of the measured data. Two invariant points were found corresponding to simultaneous equilibria as follows: Point 1: PbS, PbSO4PbO, PbSO4.2PbO, PbSO, - 4PbO, and SO2 Point 2: Pb, PbS, PbSO, . 2PbO, PbSO, - 4PbO, and SO2, From the measurements it was also possible to calculate the thermodynamic properties of the three basic sulfates of lead at 298.16°K. EXPERIMENTAL Apparatus—The experimental method consisted of the measurement of the gas pressure exerted by a given reaction mixture at a given temperature. An iridium crucible was used to contain the reaction mixture. There was no evidence of attack of the iridium,* but after use at high temperature for a week

Jan 1, 1961

By D. H. Davis

HAND picking was the earliest form of coal preparation, first practiced to improve the outward appearance of the coal being loaded and to remove any pieces that might appear objection- able to the buyer. It is still extensively practiced on the plus 1-in. sizes and particularly on the plus 4-in. and larger sizes. The percentage of ash reduction that can be obtained by hand picking depends entirely upon the amount of free impurity occurring in the coal. In a particularly dirty seam, where a considerable quantity of rock occurs with the coal as mined, hand picking produces sizable reductions in ash. If the coal is prepared clean at the working face hand picking is a final check; in some cases, on the smaller sizes, it is practiced only to show that an effort is being made to prepare a clean product. Because of the variety and different methods of handling coal, the early plants were not always adapted for efficient hand picking. At most mines an attempt is made to remove the visual impurities at one or more of the following places in the surface plant? (1) in the tipple during screening; (a) on picking band, belt, or shaking conveyors;*(3) during the loading of the coal as it goes into the railroad car. Whatever the physical arrangements of the plant may be, the usual practice is to run the coal over the screen, picking table or boom at such a rate that each piece of impurity is exposed to the view of the picker. Coal should be uniformly sized and spread out on the table so as not to exceed one particle in depth. The flow should be even in tonnage and the speed of travel should be from 30 to 60 ft. per minute and not exceed 80 ft. per minute. The dirtier the coal, the slower the speed required for a fixed number of pickers. Actually, picking capacity depends on the number of particles per minute that can be picked out and rejected. The percentage of impurity removed is determined by this and the average weight of piece rejected. Handling a mixture of sizes from nut to the largest lump over the same picking table or conveyor is not conducive to efficient separation by hand picking because the lump hides the smaller

Jan 1, 1943

By AIME AIME

STEADY advance has been made in the art of lead smelting and refining during the year. The bringing of natural gas to the Salt Lake valley has led to its adaptation to lead smelting operations. The Tooele plant of the Anaconda Copper Mining Co. has put into practice the high blast pressure and constant volume for lead blast furnaces, which we understand was first advanced by John F. Austin. It would appear that within limits, capacity is nearly proportional to the volume of air. If the charge is dense, a constant pressure, as in the old practice. did not get much air through the charge and the furnace slowed up. The constant volume idea makes the charge smelt at the same rate as if the charge were porous. The cost of a little additional power insures capacity operation at all times.

Jan 1, 1932

By Alex Hay

THE Sydney coal field, the largest and most valuable in Nova Scotia, is situated on the northeastern coast of the Island of Cape Breton, extending from Mira Bay on the south to Cape Dauphin on the north, a distance of 30 miles, and has a general dip northeast under the sea. (Fig. 1.) The field embraces the mining villages of Morien, Birchgrove and Reserve and the towns of Dominion, Glace Bay, Waterford and Sydney Mines. The city of Sydney is situated about midway between the northern and southern extremities of the field and on the western fringe of the productive coal measures. Sydney harbor crosses the coal field, cutting off direct rail connection between Sydney Mines and the greater part of the field to the southeast. (Fig. 2.) The coal measures are exposed in the cliffs on the coast line, which rise to an average height of 30 ft., and are almost continuous throughout the length of the field. The portion of the coal field under land forms a small segment of a circle, the greatest distance from the coast landwards is 9 miles, and it occupies an area of 200 sq. miles. The greatest distance developed seawards from the shore by mining operations is 2 ¼ miles. The strata maintain a regularity of dip at this distance, proving a submarine area of about 70 sq. miles. How much further the coal field extends seawards is unknown, but the indications are that it extends far beyond the present economical working limit and in all probability there is a vast submarine coal field. The productive coal measures are of Carboniferous age, these being underlaid by beds of sandstone, locally classed as millstone grit, which define the southern limit of the field,, while a spur of syenitic hills cuts off the coal-bearing strata on the north. Two main anticlinal folds having a general course easterly divide the field into three basins named from north to south: Sydney Mines-Lingan, Glace Bay and Morien.

Jan 1, 1929

Jan 1, 1920

By S. F. Bartram, G. A. Chase

COMPUTED X-ray diffraction powder patterns of YNi3, YNi5, and CbBe3 are available on request from either author.

Jan 1, 1968

[ ]

Jan 1, 1938

Jan 1, 1918

Herbert A. MegRaw, San Luis de la Paz, Guanajuato, Mexico (communication to the Secretary *):—I am in entire accord with the basis of Mr. Lamb's argument, that the stamp

Jan 1, 1911

PRESIDENT. CHARLES F. RAND,1 NEW YORK, N. Y. PAST PRESIDENTS. CHARLES KIRCHHOFF,1 NEW YORK, N. Y. JAMES F. KEMP,2 NEW YORK, N. Y. FIRST VICE-PRESIDENT. BENJAMIN B. THAYER,1 NEW YORK, N. Y. TREASURER. GEORGE C. STONE,1 NEW YORK, N. Y. SECRETARY EMERITUS. ROSSITER W. RAYMOND NEW YORK, N. Y.

Jan 5, 1913