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By H. H. Hasler

THE mining and removal of coal from two or more beds, either simultaneously or consecutively, in vertically adjacent areas have always been matters of concern to mine operators from both operating and recovery points of view. However, with the progressive introduction and use of electrical and mechanical facilities, such problems assume even greater proportions. In this paper typical cases occuring in Cambia County, Pa., are given and procedures whereby such problems may be .greatly reduced, if not entirely eliminated, are suggested. Throughout a considerable portion of the Central Pennsylvania bituminous coal region, particularly in Cambria County (Fig. I), the portion of the region to which references in this paper are made, large areas are encountered where two or more beds of coal occur and have been mined extensively since the earliest days of mining in the county. Generally, operations were commenced in one bed of coal on a property, following which, as conditions appeared to warrant, operations were commenced in another bed or beds on the same property, in some instances by the same operator. Operating results by no means have been uniformly successful, as the following review of some typical cases indicates, partly because of lack of experience in earlier cases and in certain later cases to disregard for the experiences of earlier operators. It is suggested that repetitions of such failures may be reduced largely, if not eliminated entirely, by adherence to a few basic principles founded upon past experiences. Geology and Stratigraphy The geology, stratigraphy, and relief of almost all of Cambria County have been studied and reported at length by the U. S. Geological Survey in its Johnstown, Ebensburg and Barnesboro-Patton Folios and other publications, by the Pennsylvania Geological Survey and by various individuals. All exposed rocks occurring within the boundaries of the county are of sedimentary origin, consisting of alternate beds of sandstone, slate, shale, fireclay, coal, limestone, etc., and all have been classified by the U. S. Geological Survey as extending from the upper strata of the Catskill formation, Devonian system, to and including, in a few hilltop areas, the lower strata of the Monongahela formation, Carboniferous system. Included within that range is the Allegheny formation, Pennsylvania series, which embraces all of the commercially important beds of coal that occur in the county, viz., the A, or Brookville, to the E, or Upper Freeport, both inclusive, shown in Fig. 2. The measures are traversed by a series of anticlines and synclines, extending in a northeasterly and southwesterly direction, which form broad, gently sloping basins (flat to 15 pct pitch, exceptionally to 25 pct). However, the topography of the surface is such that long lines of outcrops of all beds of coal overlying bed B, and to a limited extent bed B also, occur over large areas, a factor which contributed to the early and extensive development of mining activities in the county. Earliest mining developments of commercial importance were made in B, C', D, and E beds of coal, and it is in these beds that the principal mining operations are being conducted. To a limited extent, mining operations also have been conducted in local areas in the A, B rider and C beds. Coal beds being mined today range in thickness from approximately 28 to 60 in. Intervals between the respective beds of coal are variable but conform somewhat to the following general averages: A to B, 60 to 100 ft.; B to C, 50 ft.; C to C', 70 ft.; C' to D, 45 ft.; and D to E, 45 ft. The following are typical mining cases obserced over a period of years in various parts of the county.

Jan 1, 1952

By A. C. Fieldner

THE total annual energy production from coal, petroleum, natural gas and water power has been increasing at a fairly constant rate during the thirty years ending in 1930. But since 1913 the demand for the competitors of coal has increased at a rate faster than that for coal. During the last twenty years, the curve of coal production has had a generally horizontal trend; in fact, the 1930 production of coal was six per cent less than that of 1913. Economists attribute this loss of demand to greater efficiency in coal utilization and to displacement of coal by oil and natural gas. These two factors are about equally responsible, and it is evident that research has been intimately concerned with both. About sixty per cent of the bituminous coal mined in the United States in 1929 was used for generating steam, either in stationary or locomotive boilers. A decade ago seventy per cent or more was used for this purpose. This change is due largely to tremendous advances in fuel economy.

Jan 1, 1933

By R. B. Brinsmade

The following is an attempt to form a formula by which a mine can be quickly evaluated, aft,er all pertinent physical data have been collected from observations on the ground by a competent mining engineer. Assumptions. Let Q = price to be paid for the mining property. M = cost of developing the mining property to yield y tons of ore daily. P = cost of suitable plant to treat y tons of ore daily, p = value of said plant when the mine has been exhausted. C = total fixed capital investment. W = working capital investment. Then let C + W = total capital investment. y = required yield of ore daily in tons. Y = yield of ore yearly in tons, d = number of producing days per year, u = average operating profit per ton of ore. R = rate of interest to be earned on total investment of (C + W). r = rate of interest to be earned on sinking fund annuity. v = tons of positive ore available in mine. x = tons of probable ore available in mine, z = tons of possible ore available in mine, m = fractional factor to change probable to positive ore. n = fractional factor to change possible to positive ore. Q = tons of total ore available in mine. t = time in years to exhaust mine at rate Y.

Jan 1, 1909

By A. E. J. Engel

INDUSTRIAL talcs and ground soapstones both include earth materials of different chemical and mineral compositions. In general, the industrial talcs are composed of silicates that contain appreciable amounts of magnesia. Generally talc, the mineral, is a predominant or at least common constituent. Talc, the mineral, is a hydrous magnesium silicate, with a suggested theoretical formula H2Mg3 (SiO3)4 or H2O.3MgO.4SiO2, which postulates 63.5 pct SiO2, 31.7 pct MgO, and 4.8 pct H20.11 Actually different single grains or leaves of pure talc have variations in water content ranging from 3.5 pct to more than 7 pct, as well as slight differences in the proportions of MgO and Si02.16 Only a very small percentage of the ground industrial talcs produced in the United States approaches the composition given above (see Table 1). The purer talcs invariably occur as alteration products of magnesium carbonate rocks. Some of these relatively pure talcs include compact, massive types largely mined in California, which are designated as steatite.38,58 In general, steatites cannot contain in excess of 1.5 pct CaO, 1.5 pct combined FeO and Fe203, and 4 pct A1203. The less pure varieties of massive talc and mixtures of magnesian silicates are commonly called soapstones, or merely talc. Many industrial earth products classified as talc or as soapstone contain a variety of minerals, especially serpentine (H4Mg,Si2O9), chlorites (hydrous magnesium, iron, aluminum silicates), tremolite (Ca2Mg5H2[SiO3]8), anthophyllite ([MgCa]SiO3), diopside (CaMg[SiO3]2), and quartz (SiO2). The carbonates calcite (CaC03), dolomite (CaMg[CO3]2), and magnesite (MgCO3) are also present in some industrial talcs and soapstones. Some of these minerals, as well as sulphides, sulphates, and iron and manganese oxides, if present at all or in excess of minute amounts, may alter the composition of the industrial talc sufficiently to restrict materially its use or to lower or destroy its value. These factors are discussed in a subsequent section of this chapter.

Jan 1, 1949

By B. Egeberg, H. B. Smith

Britannia metal is a white alloy consisting primarily of tin and antimony, the tin greatly predominating. The alloy usually contains a small amount of copper and occasionally very small amounts of one or two other metals, such as bismuth, zinc, and lead. It is capable of being cold-rolled, it takes a high polish, and it is fairly noncorrosive; properties which make it a popular metal for many household and traveling utensils. Britannia metal is similar in many respects to pewter and has largely replaced pewter in the arts, but it should not be confused with that alloy, because pewter is essentially a tin-lead alloy, while Britannia is a tin-antimony alloy. In view of the fact that so little has been published concerning Britannia metal, the authors feel justified in presenting the results of their investigation, particularly since the behavior of this alloy under cold rolling and heat treatment differs so greatly from that of other metals and alloys. The old craftsman, engaged in the making of ornaments or tableware, heated the cold-rolled sheet metal or his finished product to a straw color corresponding to about 375" I?., claiming to produce thereby a harder and more rigid article. The fact that possibly led him to this heating was that a reheated article or sheet made from Britannia metal has a distinct metallic ring when struck a sharp blow, whereas an unheated article or sheet has a leady, dead note. No doubt he has associated the metallic ring with a greater rigidity and strength, and justly so, as will be seen later. The approximate analysis of the metal we investigated was 91 Sn, 7 Sb, 2 Cu, and the molten metal was bottom-poured into an iron mold yielding an ingot 7 3/4 in. wide by 11 in. long and % in. thick, the casting temperature being 800" F. The ingot was cold-rolled to a sheet 0.032 in. thick, sufficiently large samples for experimental purposes being cut from the sheet at intermediate stages. The samples were all tested for hardness with scleroscope and Brine11 machine, then heated to 212" F. for 30 min., and again tested after cooling to room temperature. The same samples were heated successively at 300°, 400°, and 440" F., followed

Jan 1, 1929

By H. B. Smith, B. Egeberg

Britannia metal is a white alloy consisting primarily of tin and antimony, the tin greatly predominating. The alloy usually contains a small amount of copper and occasionally very small amounts of one or two other metals, such as bismuth, zinc, and lead. It is capable of being cold-rolled, it takes a high polish, and it is fairly noncorrosive; properties which make it a popular metal for many household and traveling utensils. Britannia metal is similar in many respects to pewter and has largely replaced pewter in the arts, but it should not be confused with that alloy, because pewter is essentially a tin-lead alloy, while Britannia is a tin-antimony alloy. In view of the fact that so little has been published concerning Britannia metal, the authors feel justified in presenting the results of their investigation, particularly since the behavior of this alloy under cold rolling and heat treatment differs so greatly from that of other metals and alloys. The old craftsman, engaged in the making of ornaments or tableware, heated the cold-rolled sheet metal or his finished product to a straw color corresponding to about 375" I?., claiming to produce thereby a harder and more rigid article. The fact that possibly led him to this heating was that a reheated article or sheet made from Britannia metal has a distinct metallic ring when struck a sharp blow, whereas an unheated article or sheet has a leady, dead note. No doubt he has associated the metallic ring with a greater rigidity and strength, and justly so, as will be seen later. The approximate analysis of the metal we investigated was 91 Sn, 7 Sb, 2 Cu, and the molten metal was bottom-poured into an iron mold yielding an ingot 7 3/4 in. wide by 11 in. long and % in. thick, the casting temperature being 800" F. The ingot was cold-rolled to a sheet 0.032 in. thick, sufficiently large samples for experimental purposes being cut from the sheet at intermediate stages. The samples were all tested for hardness with scleroscope and Brine11 machine, then heated to 212" F. for 30 min., and again tested after cooling to room temperature. The same samples were heated successively at 300°, 400°, and 440" F., followed

Jan 1, 1929

By J. T. Michalak, H. W. Paxton

The recovery of the initial flow stress of poly-crystalline iron is characterized by a) a logarithmic time dependence; b) an increasing activation energy with increasing recovery; c) an increased ?,ate and fraction of recovery with decreased temperature of deformation; and d) an increased rate with increased deformation. Isochro)ml studies of the recovery of single crystals revealed more sluggish recovery. The original flou3 stress of single crystals could be regained by recovery anneals at 800"or 900°C. ThE great majority of the theoretical treatments and experimental studies of strain-hardening have been concerned with the close-packed lattices.' Very little effort has been expended on the bcc structure so that the theory of work-hardening of this lattice is essentially nonexistent. The limited amount of experimental data resulting from the direct studies on silicon-iron,2 low-carbon steel,3 and purified irons4"7 does not as yet permit a detailed analysis of the strain-hardening. Studies concerned with the effects of annealing following deformation have been few in number," have been somewhat limited in extent, and have had the disadvantage of using irons containing a substantial impurity content. The present research was undertaken to augment the limited knowledge we have of the characteristics of a bcc metal as regards strain-hardening and recovery from the strain-hardened state. The recovery of the flow stress has been employed since it was felt that the stress associated with the hardened state gives at least a fair qualitative description of the state of the imperfections causing the hardening. The study was concerned primarily with the recovery of flow stress following strain-hardening of polycrys-talline, zone-melted iron as a function of the amount of deformation, the temperature of deformation, and the time and temperature of the recovery anneal. A limited investigation of the recovery of the initial flow stress of single crystals of this same material as a function of the recovery temperature was also conducted in conjunction with the Lambot X-ray technique." MATERIAL The zone-melted iron used in this investigation was obtained through the courtesy of the American Iron and Steel Institute and Battelle Memorial Institute. The analysis, as given by the supplier indicated a maximum impurity content of 0.02 wt pct excluding those impurities listed in Table I. (The actual impurity content is very probably less than this since detection limits were considered as the amount of a particular impurity level.) Also listed in Table I are the interstitial impurity contents of the iron at various stages of experimental work indicating that these im-

Jan 1, 1962

By H. M. Otte

Certain choices for the shear elements of the inhomogeneous distortion in the phenomenological theory of martensite formation are examined for their agreement with crystallographic and X-ray data of iron alloys. The assumption that the shear elements must represent slip or twinning systems characteristic of bcc metals is found to covey all observations, even when a small uniform dilatation is taken into consideration. In bct martensite, (011) becomes a possible twinning or faulting plane, in addition to {112), and qualitatively similar X-ray line broadening is to be expected from both. The basic concept inherent in the current theoriesl-4 of the formation of martensite is that the interface between the parent (austenitic) and product (martensitic) phase is an invariant strain plane (i.e., one that is undistorted and unrotated). Experimental evidence that the interface is of such a nature is available in certain transformations2'5'6 but for the transformation in iron alloys direct observation has not proved enlightening. Internal strains resulting from the formation of the small martensite platelets within the parent austenite matrix7 make it difficult to produce the desired evidence. Indirect evidence, however, such as the continuity of scratches in passing from untrans-formed to a transformed region, strongly indicates that the habit plane in iron alloys is an invariant strain interface. The scatter in habit planes in a given specimen8 would suggest that internal stresses have a slight but definite influence. On the other hand, composition changes which affect the lattice parameter can alter the habit plane appreciably, and by an amount greater than the scatter.' The success of the theories depends on the choice made for the "inhomogeneous distortion" or "complementary shear'' in the analysis and also on the choice for the parameter 6 representing a small uniform dilatation. In the approach developed by Wechsler, Lieberman, and Read'," it is implicitly assumed that 6 is unity. In the case of iron alloys, all observations cannot be explained without varying either the inhomogeneous distortion or 6 . Bowles and Mackenzie3 considered only the effect of varying d. They found it difficult to reconcile the wide scatter of habit planes with the theory and were forced to the conclusion that it may also be necessary to consider variations or different choices of the inhomogeneous distortion. Wechsler and Read" considered a limited number of possible choices for the inhomogeneous distortion, but no variation in 6, though this could easily have been introduced if so desired. It is the purpose of the

Jan 1, 1961

By A. P. Anderson, J. H. Jensen, W. E. Breckoff

Bromine is the intermediate member of the halogen family of elements between iodine, a solid, and chlorine, a gas. The name is derived from the Greek "bromos," meaning stench. Bromine is the only nonmetallic element that is liquid at room temperatures with a melting point of -7.2° C and a boiling point of 58.78º C. Reddish brown in color, it dissolves easily in water to yield a red solution. Bromine volatilizes at ordinary temperatures to a red vapor that is very irritating to the eyes, nose, and throat. Density of the liquid is 3.12 and gas weighs 7.59 gpl at standard conditions. As the element is highly active, it exists in nature only as bromide compounds. Bromine was discovered by Antoine Jerome Balard in seawater bitterns in 1826 and first prepared in quantity in 1860. Distribution Bromine is widely distributed in nature and compounds occur in solution in natural brines, in seawater, saline lakes, oil and gas well brines, and in evaporite chloride minerals. The concentration of bromine salts ranges from 60-65 ppm in seawater to several thousand ppm in oil well brines and saline lakes. The distribution of bromine in marine evaporite minerals and in the solutions from which they crystallized was determined many years ago by H. E. Boeke (1908). Theoretical aspects regarding the geochemistry of bromine have been published in numerous papers (Raup and Mite, 1969). Bromine occurs in solid solution in carnallite and sylvite associated in potash deposits; in halite in salt beds; salt in oil shales; and in trona deposits. Its presence is useful as a guide in geochemical exploration. The analysis of small amounts of bromides in the presence of large amounts of chlorides is discussed by W. Schwerdtner (1963). Manganese, iron, and iodine may interfere with the determination. Other analytical methods are discussed at length in the literature (Stenger and Atchison, 1964). Sources and Reserves The sources and reserves of bromine, given in Table 1, appear ample to meet present and foreseeable requirements in all producing countries. With the occurrence of bromine salts in seawater and other brines, the potential for bromine production is worldwide. It has been estimated that 99% of all commercially recoverable bromine is in the ocean. However, actual subterranean brines having a higher bromine content than seawater will continue to be the preferred sources of bromine for the foreseeable future. [ ]

Jan 1, 1983

By A. M. Gaudin, F. W. Bowdish

MINERAL dressing is an industrial art concerned with the treatment and separation of solids suspended in fluids. Knowledge and evaluation of the area of solid-fluid interface is important in all cases except those involving only large pieces of solid. In fact, many problems relating to comminution, to flotation, to thickening and classification, could be dealt with more rationally if the interfacial area were known. A number of methods have been proposed for the measurement of the surface of certain finely divided solids. Among them are methods using rate of dissolution of the solid,7 its magnetic remanence,3 the turbidity of its suspension,8 and the character of the size distribution of the material.9 The first two are limited to one mineralogical species per sample; the third has certain optical limitations, especially for mineral mixtures, and the fourth is based on an extrapolation of uncertain validity. The need of a better and more general method of surface determination has long been felt, therefore. The method of P. H. Emmett,4 based upon the low-temperature adsorption of vapors, appears to fulfill this need. This method consists in determining the amount of nitrogen that is adsorbed by a given sample of solid at the temperature of boiling nitrogen. The more surface there is on the solid-both internal and external-the more nitrogen is abstracted. In actual operation, the method is somewhat less simple than has been stated so far, in that the nitrogen is adsorbed in an incomplete layer, the completeness and thickness of the layer being related to the pressure of the nitrogen in contact with the sample .2 This circumstance makes it necessary to determine the nitrogen adsorption for three or more values of the nitrogen pressure. APPARATUS In the Richards Mineral Dressing Laboratories an Emmett apparatus has been built and tested (Figs. 1 and 2). A mechanical vacuum pump B and a mercury diffusion pump A work in series to give a high vacuum. The sample, placed in bulb D, can be evacuated by this pump train by suitable operation of the stopcocks in the glass tubing that connects the various parts of the apparatus. C is a McLeod gauge, used to ascertain the order of magnitude of the vacuum obtained, and not for accurate pressure measurements. Pressure measurements are made in the mercury manometer F and gas-volume measurements in the gas burette E. Gases are stored in flasks L (nitrogen) and K (helium), arranged so that definite quantities of these gases can be introduced into

Jan 1, 1944

By Holbrook G. Botset

It is possible by means of the electrolytic model to simulate water-flooding or gas recycling systems involving input and output wells, and also the encroachment of a natural water drive. The results are obtained pic-torially, and by simple measurements and calculations the percentage of recovery is obtained qualitatively as a function of the total input. Introduction The increased demand for petroleum products, together with the decline in discovery rate and the higher cost of recovery as deeper formations are brought into production, has stimulated interest in methods for studying and predicting efficiencies of various production programs. Among methods Of recovery that have become of increased significance recently are gas recycling in condensate fields and secondary recovery by water-flooding. The electrolytic model is a useful device for studying such methods in the laboratory, at least in a qualitative way. The original experiments with electrolytic models and the development of their application to the study of secondary reCoverY problems were published in 1933. 1,2,3 Subsequently other investigators continued the development and modification of the bait method, with resultant improvements and extension of its applications.4-7 The method and equipment to be described here are thought to represent still further improvement in the results obtainable, with increased validity in their application to field problems. Sand OF Principles of Operation The underlying theory of the operation of the model is given in references I, 2 and 3. However, a brief statement of principles involved is given herewith. The applicability of the model is based on the fact that Ohm's law and d'Arcy's law are exactly analogous; whence, electrical flow through a conducting medium may be used to simulate homogeneous fluid flow through a permeable medium. If two electrodes are placed in a conducting (ionized) solution and connected to the positive and negative terminals of a source of direct current, the positive ions of the solution will move toward the negative terminal, Since the velocity of an ion in an electrolytic medium is proportional to the electrical gradient, just as the velocity of a fluid particle in a porous medium is proportional to the pressure gradient, the motion of the ions in the potential field will be the same as the motion of fluid particles in a porous medium if the positive and negative terminals (input and output wells) and boundary conditions are made equivalent in shape and distribution. In order for the analogy to hold exactly, the sand must be assumed to have uniform porosity and permeability and the input

Jan 1, 1946

By Holbrook G. Botset

It is possible by means of the electrolytic model to simulate water-flooding or gas recycling systems involving input and output wells, and also the encroachment of a natural water drive. The results are obtained pic-torially, and by simple measurements and calculations the percentage of recovery is obtained qualitatively as a function of the total input. Introduction The increased demand for petroleum products, together with the decline in discovery rate and the higher cost of recovery as deeper formations are brought into production, has stimulated interest in methods for studying and predicting efficiencies of various production programs. Among methods Of recovery that have become of increased significance recently are gas recycling in condensate fields and secondary recovery by water-flooding. The electrolytic model is a useful device for studying such methods in the laboratory, at least in a qualitative way. The original experiments with electrolytic models and the development of their application to the study of secondary reCoverY problems were published in 1933. 1,2,3 Subsequently other investigators continued the development and modification of the bait method, with resultant improvements and extension of its applications.4-7 The method and equipment to be described here are thought to represent still further improvement in the results obtainable, with increased validity in their application to field problems. Sand OF Principles of Operation The underlying theory of the operation of the model is given in references I, 2 and 3. However, a brief statement of principles involved is given herewith. The applicability of the model is based on the fact that Ohm's law and d'Arcy's law are exactly analogous; whence, electrical flow through a conducting medium may be used to simulate homogeneous fluid flow through a permeable medium. If two electrodes are placed in a conducting (ionized) solution and connected to the positive and negative terminals of a source of direct current, the positive ions of the solution will move toward the negative terminal, Since the velocity of an ion in an electrolytic medium is proportional to the electrical gradient, just as the velocity of a fluid particle in a porous medium is proportional to the pressure gradient, the motion of the ions in the potential field will be the same as the motion of fluid particles in a porous medium if the positive and negative terminals (input and output wells) and boundary conditions are made equivalent in shape and distribution. In order for the analogy to hold exactly, the sand must be assumed to have uniform porosity and permeability and the input

Jan 1, 1946

The Office of Price Stabilization broke the copper price loggerhead between the U. S. and Chile when it permitted copper wire and brass mills to add to their ceiling prices 80 pct of the increase in cost of foreign copper above the 27 1/2 cents per pound specified in the agreement with Chile. Another step forward in the processing of taconite seems to have been made with the patenting of a process for the strengthening of taconite pellets. The patent was issued to Fred D. De Vaney and assigne to the Erie Mining Co., of Hibbing, Minn. Strength of the pellets is improved by adding from one to five pounds of starch or sodium silicate. A new iron ore deposit discovered on Vancouver Island will start producing soon, and is expected to yield 2 million tons of magnetite over its span of operation. A new mill will be built by the Argonaut Construction Co., of San Francisco, at the deposits of the Utah Construction Co., its parent organization. The Organization for European Economic Cooperation banned the use of nickel and nickel alloy in the manufacture of about 500 products in an attempt to conserve nonferrous metals in short supply. Some 18 members of the organization have already volunteered to restrict nickel consumption.

Jan 1, 1952

The following additional notes about prices of coal in the early days were collected from the sources shown. Several data about canal tolls and labor conditions are also included. 1796, November: "The inhabitants lay it (coal) in at about 3;d. (83¢) sterling per bushel." (Ref. 73: p. 147.) 1804, March: "In March, 1804, I sent a person accustomed to mining to open the vein of coal, and to load the ark, which was accomplished, and early in the month of April the ark, with the first cargo of bituminous coal passed safely the Conewago falls, and landed her coal at Columbia, Lancaster County. The coal was sold at 31¢ per bushel at Columbia." ($7.75 per ton). This was the first coal from Clearfield County near the town of that name. (Letter from William Boyd: Pa. Senate Jour., 1833-1834, vol. 2, p. 561.) 1807: The following notice appeared in the Bedford Gazette: "Huntingdon, June 4. "Stone Coal.-Such of the farmers as wish to make experiment with stone coal as a substitute for plaster, in manuring their Indian corn, may be supplied with coal gratis upon application to Peter Hughes, at Mr. Riddle's mines, on the Raystown Branch. The proprietor of the mines offers not only to refund the carriage, but to pay the expenses of applying the coal, if upon a fair experiment it is found to be inferior to plaster, which now sells at two dollars per bushel." (Ref. 735: p. 708.) 1809: Coal was delivered in Pittsburgh at 5¢ per bushel or $1.25 per net ton. (Ref. 444: p. 50.) Coal was delivered in Connellsville at 4¢ per bushel or $1.00 per net ton. (Ibid.: p. 185.) 1810: Pittsburgh.-"Coal may be obtained of a good quality, ready delivered at 5¢ a bushel." ($1.25 per net ton.) (Ref. 315: vol. 2.) 1811: "It (coal) costs 6¢ a bushel at your door." ($1.50 per net ton.) (In Pittsburgh.) (Ref. 277: 1811, p. 68.) 1814: At Columbia, now part of Donors, Washington County, Pa., an original sale of lots in 1814 gave the purchaser of each lot the right to mine stone coal gratis from a bank on the property. (Ref. 410: vol. 1, p. 547.) "A laborer is able to dig upwards of 100 bushels per day." (4 tons.) (Ref. 277: 1814, p. 109.) A paper about the early newspapers in West Virginia says: "Collier Wanting. From 10 to 20 steady and industrious men, who understand digging coal, may obtain high wages in Kenhawa for that business, if immediate application is

Jan 1, 1942

By E. P. Whittemore

Experience with the ASC multipoint gas lift system was obtained in Colonia zone of the West Montalvo field near Oxnard, Calif. The wells in this pool produce from depths varying from 10,500 to 12,000 ft. Oil gravity is generally 14 to 15' API with a few extremes of 12 and 20" API. Some salt water is produced which causes some very viscous emulsions. Viscosities at 150F (which is the approximate wellhead temperature) vary from 5,000 to 100,000 SSU. Most of the production is by gas lift, although a few wells are produced by rod and hydraulic pump. About half of the gas-lift wells are on continuous flow and the remainder are on intermittent lift using large, ported, pilot-operated valves for single-point transfer of gas from casing to tubing. Gas-liquid ratios vary from about 6 to 10 Mcf/bbl of gross fluid lifted. Wells are produced to a 450-psi trap system. The following remarks will be confined to intermittent lift only, since this is the type of lift which has been achieved with the ASC valve system. The maximum gross fluid which has been produced by single-point intermittent lift is about 350 B/D in 3-in. tubing and 200 B/D in 21/2-in. tubing with gas-liquid ratios of approximately 7 to 9 Mcf/bbl. Some design changes could reduce this ratio. The ASC multipoint system has provided production as high as 480 BOPD in 21/2-in. tubing with gas-liquid ratios just under 4 Mcf/bbl. To be able to apply the multipoint system, it is recommended that a detailed explanation be obtained concerning transition-point pressure and stabilizer setting—what its significance is to the string design, how it may work for or against the operation of the well, how it is related to tubing sensitivity and how it affects the unloading operation. The unloading operation may only be of academic interest in a technical paper, but to the production foreman, unloading and setting the valves in operation is a very real problem and should be understood in detail. One item touched lightly in the paper was the unloading valve. This valve controls the maximum pressure at which the well can be operated. When lifting heavy viscous fluids, it is most important to set this valve for the maximum possible realistic operating pressure at the surface. If the well lifts easily, it is simple to set the ASC valves at a lower operating pressure and the unloading valve will remain closed; but if the well happens to be heavier to lift than anticipated, it may be desirable to operate on the unloading valve itself and use all the energy obtainable at the bottom of the hole. In the Colonia pool very heavy wet-gas gradients are experienced due to the viscosity of the liquid and the dense mist which is left behind a slug of fluid. There are many combination strings of 3- and 21/2-in. tubing. This aggravates the wet-gas gradient problem and provides wet-gas gradients of about 50 to 70 psi/1,000. An advantage which multipoint lift has provided is increased slug efficiency through better maintenance of pressure under the slug and decreased fall back as the slug passes up the tubing. By using multipoint injection, wet-gas gradients have been reduced to about 30 psi/1,000. This has reduced bottom-hole operating pressure and given a production increase. The ASC valve is not a simple device. It's operation is difficult to understand, and it must be understood to be used efficiently in gas-lift design. Operating problems are difficult to diagnose—whether they be caused by the fluid lifted, valve malfunction, lift gas rate, or operating pressure. Calculations and reasoning are required to find out what is causing the problem. Inherent in the ASC valve is the inability to create large pressure differentials across a slug. Large differentials may be required to overcome the inertia of very viscous fluid as it is being accelerated in the bottom of the hole. This is tied back to the design of the unloading valve and is one reason for the importance of setting the unloading valve for the highest possible operating pressure. ~u; to the narrow spread the ASC valves provide, it is impossible to cycle slower than about 24 cycles/day on choke control. If small production of 150 BOPD and less is expected, a surface time-cycle controller will be required if the most economical operation is to be achieved. To achieve a satisfactory operation, the operator must keep a record of any changes made in the operating pressure of the ASC valves. Anything which may cause changes in casing pressure in excess of the stabilizer setting will change the valve operating pressure, and if this is not noted from daily inspection of the well casing-tubing pressure recorder charts, the operator will lose control of the well. Significant results can be achieved using ASC valves; however, considerable knowledge is required to design with them, and attention to detail is required for satisfactory field operation.

Jan 1, 1965

By H. H. Stout

In the early fall of 1925, the writer was conducting, in the Ledoux and Co. laboratory, New York, experiments directed toward ascertaining the effect on its impurity content when cathode copper was subjected to a current of various gases at an elevated temperature below the melting point. The apparatus consisted of a vertical I-in. dia. silica tube about 12 in. long, heated on the outside. The cathodes were broken to pass 3/8-in. mesh, and a current of various different gases was passed up through a 4-in. long column of these loose cathode particles in the vertical tube furnace. Temperature was maintained to 1500º to 1600ºF. and the gas treatments lasted from 3 to 6 hr. The writer observed that whenever reducing gas (H2 or CO) was used, these cathode particles stuck together at points of contact with each other. The cohesion was so marked and tenacious that an examination was made of the fractured surfaces, when cathode particles were broken from the cluster. Crystal growth was always found to have taken place across the surfaces where separate particles were in contact, but only after all oxides, sulphates, etc., had been completely removed. The idea of a possible new process was then conceived and was disclosed to A. M. Smoot (V. P. Ledoux and Co.) with intent to obtain his views. The first conception as given Smoot was "to gas-clean broken cathodes, put them in an extrusion press, solidify and extrude them at around 1500ºF." Smoot's reaction, after a few moments considera- tion, was, "It looks perfectly all right to me.'' The writer and his assistants, W. H. Osborn and H. H. Stout, Jr., after conferring as to ways and means, decided to go ahead with preliminary laboratory experiments, which, it was thought, would move the new process from the possible to the probable. This program followed a course indicated by three basic considerations: 1. Since brittle cathodes were often unintentionally produced, it seemed probable that the laws controlling this type of deposition could be ascertained. 2. We had already proved the gas-cleaning feature. 3. There remained to prove: whether a sound, homogeneous metal billet could be produced with crystal growth established over the entire surface of each individual particle in the billet; and, if so, what would be the physical properties? Osborn arranged with Columbia University for conducting experiments in its research laboratory to prove or disprove the third item; Columbia assigned C. A. Phillipi, Jr. to assist in the project. A press with a cylinder 2 in. high and of I-in. dia. was used. It was surrouilded and heated by a resistance coil 01 Nichrome wire. Broken tough cathodes were used. Experimental Procedure The first run took place March 18, 1926. The resistance wire gave out when temperature of 1000ºF. was obtained. Pressure was immediately applied: perceptible ram movement stopped when 39,000 lb. per sq. in. on the copper was reached, with a maxi-

Jan 1, 1941

By Richard W. Markley

A centralized online data acquisition system has been developed by the U.S. Bureau of Mines Pittsburgh Mining and Safety Research Center for rapidly digitizing, storing, and processing experimental signals originating up to 1100 feet away from a central computer. This system, which services seven laboratories, is currently based on a CDC System 17 1/- computer with 56K of semiconductor memory, four disk drives (one shared online with a CDC 1700), two magnetic tape drives, high-speed A/D hardware, and other input/output peripherals. The laboratories are linked to the central computer by 15-pair cables and signal conditioners and to the computer's communications controller by modems and current loops. The A/D throughput rate is approximately 30,000 samples per second (9 bit plus sign resolution) and permits scanning about 30 instruments once every millisecond for up to 100 seconds, being limited only by disk capacity. The laboratories serviced by this facility conduct explosions research and include such facilities as an Experimental Coal Mine Explosion Facility (45 channels), a Constant Volume Combustion Laboratory (4 channels), and a Simulated Coal Mine Laboratory (15 channels). Personnel support includes one systems analyst, two applications analysts, one operator, and a hardware technician. The system has performed adequately for burst-type data acquisition, but due to a lack of long-term reliability (24 hours) of the real-time multiprogramming operating system and unpredictable power failures, slow phenomena signals are generally digitized and stored offline. This latter data is input to the computer through peripherals such as a high-speed paper tape reader, or high-speed asynchronous communications ports. Processing of data is done either in real-time (as soon as data is collected) or in batch mode. Smaller batch jobs are run on this computer, and all others are transmitted by means of the system's high-speed UT 200 terminal simulator to a CDC-6000 series computer.

Jan 1, 1977

By H. M. Wilten

THIS article presets a view of a problem encountered in petroleum refining in the deterioration of equipment used in condensation of vapors and cooling of liquids. Discussion is limited to the problems of shell- and tube-type exchangers and condensers. In this service shell- and .tube-type equipment is gradually displacing other types and, for this reason, its economic importance ill oil-refining practice is also increasing. Considering oil - refinery practice during the last two decades one can readily see many important improvements in the apparatus used. Briefly, the present equipment is safer, more efficient, and Ignore economical. Improvement in apparatus used for the condensation of distillates has, in my opinion, been less than that in other essential distilling apparatus. So it is hoped that this discussion will stimulate research among the producers as well as among the consumers of this equipment with a view to ameliorating this condition.

Jan 1, 1937

By John P. Bryant, Samuel Kincheloe

Plant nutrients are obtained by plants from both the air and the soil. Carbon dioxide, a gaseous form of carbon and oxygen, supplies the carbon which usually makes up 50% or more of plant structure. Plants are capable of absorbing carbon dioxide directly from the air. Most of this nutrient comes from the air, although some carbon dioxide is absorbed by soil water and taken into the plant as liquid. Growing plants use more water than any other substance. Plant nutrients in the soil dissolve in soil water; soil water entering the plant carries nutrients into the plant structure. Water is then given off into the air as the plant breathes or transpires. Inorganic or mineral nutrients essential to plants are supplied through the soil. Inorganic or mineral composition of plants usually is less than 5% of their weight. In most crop-growing areas, much of this nutrition is inadequately supplied from the soil and must be provided by fertilizers. Proper fertilization of a soil to improve its mineral level and productivity is the role of the fertilizer industry. The 13 essential plant nutrients which often must be added to soils or plants and are generally considered fertilizer minerals are categorized as primary minerals (nitrogen, phosphorus, and potassium); secondary minerals (calcium, magnesium, and sulfur); and micronutrients, or trace minerals (boron, iron, manganese, copper, zinc, molybdenum, and chlorine). These classifications are based on quantity of nutrients utilized by plants and have no implication as to function or degree of necessity. One point of major significance to the fertilizer industry is that not all nutrient carriers supply that nutrient in a chemical form which will be available to the plant. Thus, a product which may be considered a fertilizer mineral may require substantial processing or may require substantial processing or treatment before it becomes useful as a nutrient carrier. Fertilizer Industry Scope Until about 1900 demands for higher crop yields were met simply by bringing new agricultural lands into cultivation. Since that time great progress has been made in increasing yields through fertilization and improved varieties and cultural practices. The importance of the fertilizer industry to the economy and welfare of the US is widely recognized. Fig. 1 illustrates the relationship of lime and fertilizers to crop yields. In terms of tons of fertilizer products, the growth of the industry has been phenomenal, particularly between 1950 and 1980. Table 1 shows the increase in fertilizer usage. Primary Plant Nutrients in Fertilizers Primary minerals (nitrogen, phosphorus, and potassium) are designated as such because [ ]

Jan 1, 1983

By P. Chiotti, J. T. Mason

Ther?nal, X-ray, metallographic, and vapor pressure data were obtained to establish the phase diagram and standard free energy, enthalpy, and entropy of formation for the compounds in the Sw-Zn system. Four compounds, SmZn, SmZn2 , SmZn4.s, and SmZn8.5, melt congruently at 960°, 94Z°, 908°, and 940°C, respectively. The cornpounds SlnZns, Sm3Znll, and SnzZn7.3 undergo peritectic decomposition at 855", 870°, and 890C, respectively. Another compound of uncertain stoichiometry, SmZn11, undergoes peritectic decomposition at 760°C. Four entectics were observed with the following compositions in weight percent zinc and eutectic tenzperatures in degrees Centigrade: 12 pct, 680°C; 36 pct, 890°C; 58 pct, 850°C; and 72 pct, 900°C. An allotropic transformation and a composition range were observed for the SmZnz compound. The transfor)nation varies from 905" to 865°C as the zinc content increases from 16.0 to 48.5 wt pct, respectively. The free energy of formation of the compounds at 50PC varies between -15.9 kcal per mole for SmZn to -51.1 kcal per mole for SmZn,.,. Corresponding enthalpies vary between -19.2 to -78.3 kcal per mole. The ther-modynamic properties for the liquid alloys are described by the relations: A search of the literature revealed very little information on the Sm-Zn system. Chao et al.&apos; as well as Iandelli and palenzonai have reported the structure of SmZn to be cubic B2 type and Kuz&apos;ma et al3. have reported the structure of -sm2zn17 to be of the Th2Ni17 type. The purpose of this work was to establish the phase diagram of this system, to determine the zinc vapor pressure over the solid two-phase regions of the SYstem, and to calculate the thermodynamic properties of the compounds. MATERIALS AND EXPERIMENTAL PROCEDURES The metals used in this investigation were Bunker Hill slab zinc 99.99 wt pct pure and Ames Laboratory samarium. Analysis of the samarium by chemical, spectrographic, and vacuum-fusion methods gave the following average impurities in ppm: Nd, <200; Eu, <100; Gd, <100; Y, <50;Ca, 225; Ta, 400; Mg, 10; Cu, ~50; 0, 175; H, 20; and N, 15. The elements Fe, Si, Cr, Ni, Al, and W were not detected. The samarium was received as sponge metal and was kept under argon except when being cut with shears and when being weighed. Tantalum was found to be a suitable container for alloys with zinc contents up to the Sm2Znl, stoichio-metry. At higher zinc contents the grain boundaries of the tantalum containers were penetrated by the alloy and the containers failed during prolonged annealing. About 25 g of massive zinc and samarium sponge were sealed in tantalum crucibles equipped with thermocouple wells. These crucibles were in turn sealed in stainless-steel jackets. All closures were made by arc welding under an argon atmosphere. The samples were equilibrated in an oscillating furnace and in some cases were given various heat treatments in a soaking furnace. After appropriate heat treatment the steel jackets were removed and the alloy subjected to differential thermal analysis. The apparatus was calibrated against pure zinc and pure copper and found to reproduce the accepted melting points within 1°C. Alloys were subsequently subjected to metallographic examination and those of appropriate compositions were used for X-ray diffraction analysis and for zinc vapor pressure determinations. The vapor pressures were determined by the dewpoint method. Both the differential analysis and dewpoint measuring apparatuses have been described in earlier papers.4, 5 All alloy samples were etched with Nital (0.5 to 3 pct nitric acid in alcohol) except the samarium-rich alloys. These more reactive alloys were electro-polished in a 1 to 6 pct HClO4 in methanol solution at -700c at a potential of 50 v. EXPERIMENTAL RESULTS Phase Diagram. The results of thermal analysis are indicated by the points on the phase diagram, Fig. 1. Eight compounds and four eutectics were observed. The composition of the compounds and their melting or peritectic temperatures are given on the phase diagram. The four eutectic compositions in wt pct zinc and eutectic temperatures in % are: 12 pct,- 680°C; 36 pct, 890°C; 58 pct, 850°C; and 72 pct, 900°C. The stoichiometry of the most zinc-rich compound is still uncertain, but is very likely either SmZnll or SmZnlz. However, to simplify the presentation which follows it will be referred to as SmZnll. As shown on the phase diagram the phase regions for some of the samarium-rich alloys have not been unambiguously established. A sample of pure samarium was observed to transform at 924°C and to melt at 1074"C, in good agreement with corresponding val-

Jan 1, 1968