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By A. Lubinski, C. R. Stewart, K. A. Blenkarn

Storage porosity has been considered one of the important pore geometry characteristics of heterogeneous-porosity limestones. Storage pores are only containers for fluids, in contrast to flow channel pores which both contain fluids and provide continuity for fluid flow. The concept of another geometry characteristic, "poro-striction", is presented as a second pertinent variable in describing limestone pore space. In simple terms, poro-striction is a measure of the flow resistance between storage and flow channel pores. Alternating-flow core-testing theory provides flow relationships which can be used to divide the pore space of heterogeneous-porosity media into flow channel and storage pores and to measure the "porostriction" of the latter. Experimental application of this theory to naturally occurring heterogeneous limestones shows that "porostriction" and the ratio of storage to flow channel pores can be estimated. Porostriction and porosity ratio are microscopic characteristics which should influence oil-recovery efficiencies during certain types of displacement processes. A knowledge of pore geometry should be valuable in designing or selecting the most effective oil-recovery process for heterogeneous limestones containing storage porosity. INTRODUCTION The primary and secondary recovery of oil from limestone (carbonate) reservoirs has been and will continue to be a major source of the world's supply of petroleum. Oil recovery from this type of formation is strongly influenced by the size, shape and arrangement of the pore spaces which hold the formation fluids. Therefore, it is expected that better knowledge of pore geometry would lead to design of more effective recovery processes. The concept of storage and flow channel pores has been presented as an important characteristic of limestone porosity.1 In this concept, storage pores are only containers for fluids, whereas flow channel pores are those pores which both contain and transmit the fluids. The work reported herein involves the concept of an additional pore characteristic called "porostriction". This characteristic can be visualized as the flow resistance between the storage and flow channel pores. This resistance is an important pore geometry characteristic because it determines how easily gas and oil can replenish fluids removed from the flow channel pores. Fatt and co-workers at the U. of California have studied the effect of storage porosity and a factor similar to porostriction on transient-flow response of models of porous media during a pressure build-up or drawdown test.55 These models consisted of porous sandstone cores with artificially simulated storage pores. It is the purpose of this paper to describe tests which permit the storage porosity and porostriction of actual reservoir core samples to be estimated. The tests used for this purpose involved not transient tests but, rather, an alternating-flow technique in which pressure and flow are varied according to a sine-wave relationship. This technique may offer advantages over transient methods. THE POROSTRICTION CONCEPT Before discussing alternating-flow (A.F.) tests in core samples, it is necessary to define the porostriction parameter. For this purpose attention is focused upon an elemental volume v representative of a porous medium having both flow channel pores and restricted-access storage pores. For such an elemental volume, it is considered that the storage porosity is combined to form a single pore and that the access into the storage porosity may be represented by a single capillary tube connecting the single pore to the flow channels of the elemental volume. Let the radius of the capillary tube be designated as Rc and its length as L,. When fluid flows into or out of the pore, the following equation (Poiseuille's law) relates flow rate q to pressure drop p, and the physical characteristics of the tube and the fluid of viscosity jx.

By Robert L. Dean

THE pioneer mining company in Idaho to use airplanes extensively is the Yellow Pine project at Stibnite now owned by the Bradley interests. From 1901 to 1903 the gold boom at Thunder Mountain, in central Idaho overflowed to adjacent areas, prospectors discovering cinnabar and stibnite near the present site of Stibnite in Valley County. The workings were practically abandoned by 1911 through lack of capital and high costs of transportation on pack train roads over several mountain passes open only five months each year. During the World War there was some prospecting and production, and in 1921 twelve of the original companies were merged. Small-scale mining up to 1927 proved that an expenditure of several million dollars would be necessary to operate profitably. These properties were purchased by the Bradley interests during the period of 1927 to 1930. In 1927, there was no mining equipment except hand tools, no telephones, and only one building. Two mountain

Jan 1, 1935

INCREASING realization that pouring and ingot-mold practices involve many factors of fundamental importance to ingot quality and general steel-mill operations has caused these phases of steelmaking to become major concerns of operators and metallurgists engaged in control of quality and costs. Methods of pouring steel from the ladle into the ingot molds have some direct effects on ingot quality. The mold itself governs solidification and dimensions of the ingot and in so doing exerts some very tangible influences not only on ingot quality but also on product yields and general steel-mill processing. In addition, practices are employed' in the handling of molds during daily open-hearth operations that are important to quality and production costs. Therefore, pouring and mold practices must be considered highly specialized and important steps in steel-mill operations. MOLD DESIGN Mold design is difficult to discuss in a precise manner because it varies greatly throughout the industry, both in theoretical concepts and practical application, and few well developed data are available. Most ingot molds are designed to meet conditions peculiar to a given plant wherein quality standards are dictated by end-use requirements, which may differ considerably, even for the same grade of steel. The mold designer must also consider the equipment available to process ingots and the product obtained from them. Such equipment, used for stripping, heating, blooming and finishing operations, is seldom, if ever, exactly the same in any two steel plants. Thus, pronounced contrasts in mold designs can be expected to continue, even among plants making strictly comparable types of product, particularly because some producers are just beginning to realize the benefits possible from specialized designs. Certain fundamentals are used in mold design but even these

Jan 1, 1951

By C. K. Gupta, P. K. Jena

Niobium (columbium) metal in the form of a button has been produced by calciothermic reduction of niobium pentoxide using sulfur as the heat booster. In these experiments with 50 g of niobium pentoxide per batch, the influence of percentage of calcium in excess of the stoichiometric, the percentage of sulfur by weight of the niobium oxide, and the outer-wall temperature of the bomb on the quality and yield of the metal has been studied. The maximum yield on this scale was 78 pct using 50 pct excess Ca and 20 pct of S and at a bomb-wall temperature of 600°C. In experiments conducted on 500 g of niobium pentoxide, reduction with 40 pct excess Ca and 20 pct of S, and at a bomb-wall temperature of 500°C, the.yield of the metal improved to 82 to 84 pct. Some of the reduced-metal samples have been electron-beam melted and the button melts thus obtained have been observed to be extremely ductile and capable of cold reduction to 98 pct without intermediate annealing. NIOBIUM, because of its high melting point (2468oC), its ductility, its resistance to corrosion especially in liquid metals, its high-temperature mechanical properties, and its relatively low capture cross section (1.1 barns) for thermal neutrons, has potentialities as a structural material in the field of nuclear engineering. Niobium and its alloys are also gaining importance in high-temperature technology as components in aircrafts, jet engines, and missiles, electronics, chemical engineering, and surgery. In 1904 Weiss and Aichel 1 produced niobium by reduction of its pentoxide by misch-metal. Since then a large number of investigations have been carried out for the extraction of niobium from its compounds. The various routes through which the metal niobium has been extracted from its compounds can broadely be classified into the following groups: a) reduction of its halides, oxides, and fluo-salts with metals like calcium, magnesium, sodium, and aluminum;2-10 b) reduction of its halides with hydrogen and oxides with carbon or carbides;11-18 c) electrolytic winning from its halides and fluo salts;19-25 and d) thermal decomposition and disproportion ion of its halides26-30 Among the processes in commercial use at present are sodium reduction or fused-salt electrolysis of potassium niobium fluoride, carbide or carbon reduction of the oxide, and hydrogen or metallothermic reduction of the chlorides. In 1907 Von Bolton2 prepared niobium by reducing niobium pentoxide with aluminum. Dennis and Adam-sona attempted reducing the oxide with magnesium powder in argon atmosphere and the resulting metal contained as much as 5 pct O. Mondolfo8 claimed a method for the reduction of the oxides with aluminum. In the case of both magnesium and aluminum reduction, it has been stated31 that by-product oxides such as MgO or A12O3 would involve a major separation problem. Further, in the case of alumino-thermic reduction, the solubility of aluminum in niobium and intermetallic formation have to be reckoned with. In 1922 Bridge3 produced niobium by calcium reduction of niobium pentoxide. Dennis and pdamson' obtained the metal by a similar method with an oxygen content of 0.2 pct. In most of the cases of metallothermic reduction of niobium oxides mentioned above, the metal niobium is obtained in the form of powder. In an attempt to produce massive niobium metal, lock' used iodine as the thermal booster in the bomb reduction of niobium pentoxide by calcium. Massive niobium metal was obtained with a maximum yield of 75 pct containing 0.1 pct 0. Joly32 carried out experiments on calcium reduction of niobium pentoxide on a 2-kg scale using sulfur as the heat booster in a sealed bomb filled with argon. In his experiments, the reaction was initiated by passing a current through niobium spiral wire embedded in the charge. In a typical run consisting of 2000 g of niobium pentoxide, 3100 g of calcium, and 800 g of sulfur (S/Nb2O5 = 3.3), he obtained massive metal in the form of a very uneven mass with a yield of -57 pct. With lower amounts of sulfur and calcium, powder niobium mixed with small metal globules was obtained and the yield was also poor. From these experiments he concluded that this method is not a suitable one for industrial development considering the quality and yield of metal obtainable and the possible hazards with higher ratios of sulfur to niobium pentoxide in the -~charere. In the present work, a detailed investigation on the calciothermic reduction of niobium pentoxide in a stainless-steel bomb in presence of sulfur as the heat booster was undertaken on a laboratory scale.

Jan 1, 1964

By Johnston, T. L.

BISMUTH is found as native metal associated with tin, copper, cobalt, silver, gold, or other metals and in a variety of ores. The more important ones are: bismuthinite (bismuth glance), Bi2S3; bismite (bismuth ochre), Bi2O3.3H2O; and bismutite (bismuth carbonate), Bi2O3CO3?H2O. Of lesser importance are the arsenate, telluride, and vanadate. The sulfide is the most common; the others are often oxidation products from this mineral. Bismuth minerals have been found in various places in the United States, principally in Colorado and Utah, but no ores are mined solely for bismuth. In the Granite mining district of Beaver County, Utah, a stratum of limestone about 6 ft. thick has been almost completely replaced by contact minerals in which bismuthinite associated with pyrite and molybdenite was found intergrown with silicate minerals. In the early days a few small lots of ore assaying 7 to 10 per cent bismuth were shipped from this district. Native bismuth has been found in the Clifton and Tintic districts of Utah. Bismuth is produced as a byproduct in the refining of lead, copper, gold and silver ores, it being recovered from the anode mud from the Betts process. Deposits of bismuth minerals exist in Argentina, Aus¬tralia, China, Japan, Germany, Spain, Peru, Bolivia, and Canada, but Bolivia is the principal, producer and could easily supply all of the present world's demand.

Jan 1, 1933

By Truman H. Aldrich

The red, or fossiliferous, ore is found in the Clinton group of the Silurian formation. This group is from 100 to 500 ft. thick in Alabama, and its outcrops have been mapped by the State or the U. S. Geological Survey. In some places, it is entirely missing (doubtless islands in the Silurian Sea). In Etowah County, in part of Greasy Cove and vicinity, the upper seam is a coral reef impregnated with the red ore; in this same county, step faults bring up the ore in three or four practically parallel ridges. In Blount County and on Raccoon Mountain, the ore runs under the carboniferous rocks and outcrops in the valleys. When examining the logs of holes drilled for oil, wherever the drill has gone deep enough, the writer has found the Clinton group underlying the Warrior coal field. The following records of holes drilled primarily for oil, given in Bull. No. 22, Geological Survey of Alabama, show the presence of either ore or red rock, and suggest vast resources yet to be outlined and developed for ore in the future. The locations are given by number on the map. Hole No. 1 was drilled 6 miles southeast of Russellville, Franklin County, by the Woodward Oil & Gas Co. It passed through 160 ft. of the Clinton, but only a small show of red ore was found at 1280-1400 ft. A test well, No. 2, drilled near Atwood, Franklin County, in sectioil 26, township 8, range 14, penetrated the Clinton at 1608 ft. and found 38 ft. of limy red rock, also 8 ft. of some blood red ending at 1820 ft., making 46 ft. of red rock in all. It is reported that some good ore was cut through but this work was done by a churn drill. At least 400 ft. of the formation was classified as Clinton. Well NO. 3, called Frankford Well, was bored by S. A. Hobson and associates in the northwest quarter of section 7, township 6, range 12, Franklin County. At 927 ft., it is supposed to have entered the Clinton; the log is as follows: Ft. Sandy limestone with reddish, high ferruginous argillaceous inclusions 10 Same growing more ferruginous................................ 18 Hematitic limestone......................................... 30 Same with slightly less iron.................................... 23 81

Jan 1, 1925

By S. B. Christy

Jan 1, 1902

By Robert M. Dreyer

AGGREGATE With an annual domestic production of over 1.6 billion tons at a value of over $2 billion (see Table 15.1.1), the production of aggregate (crushed rock, sand, and gravel) is a basic industry of utmost economic importance. Because of the role of aggregate materials as essential ingredients of concrete, asphalt surfacing, and plaster, their delivered prices are major factors in determining the cost of construction. The annual domestic production comes from nearly 10,000 plants. About 15% of these plants account for over one-half the production. In a rapidly inflating economy, the average mine sales price of aggregate has remained relatively stable. The actual mine sales prices, however, vary greatly depending on quarrying costs in various parts of the country. Of much more importance in construction costs, however, is the delivered price of aggregate. This varies for each job, depending on the distance from the quarry and resulting transportation costs, as well as the initial cost at the mine. Because of a proliferation of regulations limiting new quarries in the vicinity of the encroaching urban sprawl, the average distance which aggregate must be transported has been increasing rapidly. Although it is impossible to derive an average delivered cost for aggregate, it should be noted that even an increase of only $1 per ton in average delivered cost over the last decade (probably a minimal assumption) would mean an annual cost $1.5 billion higher than ten years ago. In recent years, structural engineering considerations, as well as an increasing use of lightweight concrete blocks, have resulted in a rapidly increasing demand for lightweight concrete and plaster, the essential ingredient of which is lightweight aggregate. Principal lightweight aggregates are: pumice, slag, perlite (thermally expanded hydrous volcanic glass), vermiculite, and expanded shale, formed by the thermal expansion of shale and slate. The United States now has the capacity to expand, annually, over 13 million tons of shale and slate and to expand over 600,000 tons of perlite. In locating a site for aggregate production. the following factors must be considered: (1) tonnage available; (2) quality of aggregate (including local variations); (3) distance from major use areas; (4) transportation costs, including those resulting from present and possible future haulage restrictions; (5) zoning regulations; (6) operating costs, including the cost effects of compliance with local regulations governing blasting, air pollution, water pollution and drainage, noise levels, and operating periods. At one time, locating a suitable site for the production of crushed rock, sand, or gravel, in most areas, was regarded as an extremely simple task. In the past few years, however, finding a site for profitable production of aggregate has assumed ever-increasing com-

Jan 1, 1976

Jan 1, 1947

Jan 1, 1947

By Paul M. Tyler

DOES mining pay? Inasmuch as the whining of minerals from Nature is one of the world's principal sources of new wealth, this question is of general economic interest but it is obviously of even more vital concern to investors and those engaged in mining. In a previous article on "Wage Costs in the Mineral Industries,' published in the November issue, I attempted to show that wages paid workers on the job accounted for, roughly, 50 per cent of the mine dollar. Salaries normally range over 5 per cent - lower for large metal mines but higher in stone quarries and minor nonmetallic min. in, industries. Purchases of supplies, materials. fuel, and power generally aggregate within the range of 15 to 25 per cent of total receipts, with the average well under 20 per cent. The total of all such specified expenditures which may he loosely described as

Jan 1, 1934

By AIME AIME

MINERAL production of the United States is valued at over five billion dollars a year at present and the industry employs close to a million workmen, yet such maps as are available that might indicate the geographical distribution of this industry show only the location of coal and oil fields and of other mineral deposits. No recent map is available that shows this distribution in a quantitative way. The purpose of the maps and graphs here presented is twofold: (1) to give the mining engineer a clear conception of the relative value and the pattern of distribution of minerals in the United States; (2) to test the so-called block-pile (or grouped pillar) system of statistical mapping, which makes this presentation possible. (I discussed this method of mapping in an article which appeared in Economic Geology in 1939, Vol. 15, p. 185-188.)

Jan 1, 1941

The primary purpose of the Institute is to advance those sciences embraced by it through interchange of knowledge This can best be done by the presentation and discussion of technical papers by its mem¬bers Short practical papers are especially welcome In any case the author should satisfy himself that his material is of a quality that will be a credit to him and to the Institute The preparation of a good paper frequently leads to a reorientation of the author's thoughts, which is extremely valuable, and pertinent dis¬cussion thereof contributes in no small way to the professional standing of the author Members are urged to submit papers presenting the results of their work Attention to the following suggestions will greatly further the prompt and efficient handling of manuscripts 1 Subjects: The subject must be within the field of the Institute Original work, the results of field, plant, laboratory or theoretical investigations, new views on old but important problems and occasion¬ally reviews of timely and important subjects of wide interest to our members may constitute the basis of a paper The mere fact that the work is original does not necessarily justify publication it must be of a substantial nature, of value to a reasonable number of our members and worthy of permanent record It is rarely desirable to subdivide the results of a single research for publication in a variety of journals Pre¬vious publication is a bar to acceptance 2 Construction : Papers should be clearly and concisely written in good English Care in this regard insures wider reading and the saving in space permits the Institute to publish more papers The terminology and units employed should be those current in the particular field An examination of Institute publications will afford useful guidance in such

Jan 1, 1937

By G. Derge, Ling Yang, John Henderson

Self-diffusion coefficients of aluminum have been measured by the capillary reservoir technique in liquids of the CaO-SiO2-Al2O3 system containirg equimolar portions of CaO and SiO2, in the temperature range 1400o to 1520oC. For the melt containing 6.0 mole pct Al2O3 the results can be expressed by the equation D = [(4.3 * 0.3) x 104] exp [(-85,000 * 17,500)/RT]cm~sec-'; for the melt containing 12.5 mole pct Al2O3, by the equation D = (5.4 i 0.2) exp [(-60,000 * 10,00O)/RT] cm2sec-: A concept of the constitution of these melts has been developed which proposes that the ratios O/(Si +Al) and Al2 O3/CaO determine the dominant species present. In recent years considerable work has been done on the system CaO-SiO2-A12O3 with a view to elucidating the structure of liquids of this system. Conductivity,' electromotive force, 3 density,4 and activity5 measurements have all contributed to an understanding of the problem, but as yet there is no entirely satisfactory theory that can account for all the observed experimental results. In principle, measurements of self-diffusion coefficients should give further information which is not obtainable in other ways. Self-diffusion coefficients for calcium, silicon,6 and oxygen7 have been measured. The present investigation extends the series of self-diffusion coefficient measurements to include aluminum and develops a concept of constitution for liquids of this system which is compatible with all the observed experimental results. EXPERIMENTAL The technique used in the measurement of the self-diffusion coefficient of aluminum was the capillary-reservoir method,8 A126 being incorporated in the melt contained in the capillary and inactive aluminum in the reservoir melt. This method was chosen because it minimizes convection currents' in the diffusion zone. It has the further advantage that the boundary conditions are such that a slight modifica- tion of Anderson and saddington's8 solution of Fick's Law yields an equation which requires measurements only of the length and the initial and final average specific activities of the solidified melt within the capillary. where t is the diffusion time, Co is the average specific activity of the melt contained in the capillary at t = O, C is the average specific activity of the melt contained in the capillary at t = t, 1is the length of the capillary, and D is the self-diffusion coefficient. The equation is of somewhat different form than those previously applied to high temperature diffusion studies because the specific activity of the melt in the reservoir was negligible both before and after diffusion. The diffusion apparatus is shown schematically in Fig. 1. It consisted of a silicon carbide resistance furnace containing the inactive melt in a graphite crucible, internal dimensions 7/8 by 4 in., enclosed in a 1 1/4- by 1 1/2- by 30-in. McDanel tube. A 3/8-in. McDanel thermocouple sheath to which graphite radiation shields and a graphite protection tube were affixed, was used to hold the capillaries. By moving this sheath through a rubber seal at the top of the McDanel tube the capillaries could be lowered into or raised out of the melt. Temperature was measured with a Pt-Pt 13 pct Rh thermocouple which was calibrated periodically against a standard couple. The furnace temperature was controlled to ± 5°C through the thermocouple immersed in the melt. Temperature variation over the depth of the melt was less than ± 3°C. The inactive melts were prepared from pure native quartz, assaying better than 99.9 pct SiO2, A.R. grade A12O3 and A.R. grade CaCO,. The same quartz and CaCO3 were used in preparing the active melts, the

Jan 1, 1962

By Edgar L. Weinberg, W. Horatio Brown

The Austinville-Ivanhoe lead-zinc deposit occurs in the Lower Cambrian Shady dolomite. This deposit is located in southwestern Virginia in the faulted and folded Appalachian Valley and Ridge province. The ore bodies resemble the chimmey and manto deposits of northern Mexico and are formed by replacement and filling. They are confined to certain favorable zones of the Austinville and Ribbon members of the Shady. Structural and stratigraphic factors combine to control the location and form of the ore bodies. In certain places secondary oxide enrichment of the zinc minerals has contributed to the economic development of the area. It is concluded that the ore is epigenetic and is deposited by hydrothermal solutions rising through the fault "plumbing." Classification is epithermal-telethermal.

Jan 1, 1968

By Harold Margolin, W. R. Hibbard, R. W. Fenn, H. P. Moore

Deformation lines, also called etch markings or strain markings, are non-effaceable lines developed in individual grains by etching a metal specimen which has been cold worked sufficiently to cause atomic non-conformity or slight orientation differences within the grains. Etching occurs more rapidly at these lines of high chemical reactivity to produce a result similar to that revealing grain boundaries. Wider etching effects forming bands have been found. They are believed to be bands of deformation lines which form areas of measurably different orientation from the crystal matrix. The crystallite rotations causing these bands have been shown by Barrett2 to contribute to deformation textures. Although deformation lines have been observed in many metals, the amount of deformation requireti for their appearance has been established only in general terms. Mathewson and Phillips3 observed the first appearance of deformation lines in cold-rolled alpha brass at about 20 pct reduction in thickness using the standard ammonium hydroxide hydrogen peroxide etchant. Price and Davidson4 noted defor- mation lines in common high brass after 26.5 pct reduction by cold rolling using the same etchant. Johnson6 observed dark thick forklike lines in 99.99 pct pure copper reduced 31.8 pct. Adcock6 observed deformation lines in 80-20 copper-nickel alloy rolled 50 pct. Samans7 found no deformation lines in alpha brass single crystals cold rolled 9.5 pct but they did appear after 25 pct reduction using ammonium hydroxide and hydrogen peroxide etchant. Barrett and Levenson8 observed deformation bands in drawn polycrystalline iron at very small reductions in area and noted that their initial appearance perhaps depends on grain size and other conditions. They reported deformation bands in a single crystal of iron reduced 6 pct by drawing. Brickg noted that deformation lines in 70-30 brass apparently associated with I I I I ) planes appeared after reductions of from 20-50 pct by cold rolling. Brick and Williamson10 noted that in single crystals of 70-30 alpha brass "as in polycrystalline brass, no deformation markings appeared until reductions exceeded 20 pct." Cook and Richards" reported that in Copper cold rolled less than about 50 Pet few strain markings were apparent but for higher reductions many strain markings appeared transverse to the rolled direction. In a review article Brick and Phillips12 noted that previous studies had not shown deformation lines in cold rolled alpha brass below 20 pet reduction and added that 4

Jan 1, 1949

By H. P. Moore, R. W. Fenn, Harold Margolin, W. R. Hibbard

Deformation lines, also called etch markings or strain markings, are non-effaceable lines developed in individual grains by etching a metal specimen which has been cold worked sufficiently to cause atomic non-conformity or slight orientation differences within the grains. Etching occurs more rapidly at these lines of high chemical reactivity to produce a result similar to that revealing grain boundaries. Wider etching effects forming bands have been found. They are believed to be bands of deformation lines which form areas of measurably different orientation from the crystal matrix. The crystallite rotations causing these bands have been shown by Barrett2 to contribute to deformation textures. Although deformation lines have been observed in many metals, the amount of deformation requireti for their appearance has been established only in general terms. Mathewson and Phillips3 observed the first appearance of deformation lines in cold-rolled alpha brass at about 20 pct reduction in thickness using the standard ammonium hydroxide hydrogen peroxide etchant. Price and Davidson4 noted defor- mation lines in common high brass after 26.5 pct reduction by cold rolling using the same etchant. Johnson6 observed dark thick forklike lines in 99.99 pct pure copper reduced 31.8 pct. Adcock6 observed deformation lines in 80-20 copper-nickel alloy rolled 50 pct. Samans7 found no deformation lines in alpha brass single crystals cold rolled 9.5 pct but they did appear after 25 pct reduction using ammonium hydroxide and hydrogen peroxide etchant. Barrett and Levenson8 observed deformation bands in drawn polycrystalline iron at very small reductions in area and noted that their initial appearance perhaps depends on grain size and other conditions. They reported deformation bands in a single crystal of iron reduced 6 pct by drawing. Brickg noted that deformation lines in 70-30 brass apparently associated with I I I I ) planes appeared after reductions of from 20-50 pct by cold rolling. Brick and Williamson10 noted that in single crystals of 70-30 alpha brass "as in polycrystalline brass, no deformation markings appeared until reductions exceeded 20 pct." Cook and Richards" reported that in Copper cold rolled less than about 50 Pet few strain markings were apparent but for higher reductions many strain markings appeared transverse to the rolled direction. In a review article Brick and Phillips12 noted that previous studies had not shown deformation lines in cold rolled alpha brass below 20 pet reduction and added that 4

Jan 1, 1949

By W. R. Barclay

IN MY general contact with industry I have become more and more impressed with the need for the closest possible co-operation between engineers and metallurgists, and particularly with the need for appreciation of the work that each group is doing to assist the other. Also, I am convinced that from time to time it. is vitally important to a true perspective of human progress in all its branches, and certainly a salutary corrective of undue optimism and pessimism to endeavor to carry the mind hack over certain periods in the advance of technical knowledge, and form some kind of broad estimate of what has been accomplished in the application of science to industry in the fields with which we, as individuals or groups, may for the time being be concerned. We cannot without some appreciable mental effort realize what our forerunners have dine For us. If the young engineer or metallurgist entering industry today could be suddenly transported to a quarter of a century ago, and be compelled to work with the materials then available and within the limitations of knowledge then attained, he would, on his return to present-day life, have a much greater appreciation of what has been accomplished before lie arrived on the scene, and, what is even more important, a far more acute sense of its inherent value to his profession. I propose here merely to indulge in a general summary of the subject of improved engineering metals and alloys rather than in details, and to deal exclusively with developments within my own experience.

Jan 1, 1938

By H. W. Becker, C. C. Frye, A. V. Degau, A. Masuda

Natural gas containing 25.65 per cent hydrogen sulfide and 4.75 per cent carbon dioxicle is gathered frorn eight \veih arid tratzsporrcd 26 miles at a flow rate of 160 MMcf/D and at operating pressures of frotrl 1,200 to 1,800 psig. Dry desiccant dehydrators at each wellsite tnaintaitz the dew point of the gas below 17F. Telemetering facililies permit control of field operations from a central instrunlent console. Corrosion control ineasures, design coilsiderations and material specifications pertainitz to these specia1 conditions are cliscussed. INTRODUCTION Natural gas containing 25.65 per cent H2S and 4.75 pcr cent CO, is produced from the Pine Creek field, Alta. It is dehydrated at wellheads, gathered at 2.200 psig and transported 26 miles to the Windfall field where it is delivered to the inlet of injection compressors at 1,800 psig. The daily average volume of gas transported is 160 MMcf. The project is believed to be unique in its combination of percentage of hydrogen sulfide, operating pressure and transportation distance. This paper describes the project and presents details of some of the design features, corrosion control program and centralized automatic operational control. The Pine Creek field project is one phase of a joint operation of two fields—thc other being the Windfall field. The two fields lie about 30 miles north of Edson, Alta. and 20 miles west of Whitecourt, Alta., respectively, as shown on the map (Fig. 1). They are owned by the same interests and operated according to a plan for maximum economic recovery of products. The Windfall Leduc D-3 reservoir contains a rich condensate-bearing gas containing 15.5 per cent HIS. The gas from the Pine Creek field contains only very small quantities of butane and heavier products. The Windfall reservoir is being cycled to obtain maximum condensate recovery using gas from the Pine Creek field as the displacing fluid, while producing the residue sales gas for both fields from the Windfall field. The Pine Creek field development and gas-gathering facilities are shown on the map (Fig. 2). The producing formation is the Leduc D-3 reef at a depth of 11,300 ft. The original reservoir pressure was 4,590 psia at 7,400 ft subsea and the temperature is 245F. Eight wells are equippcd with dry desiccant dehydrators with the following capacity ratings: three at 35 MMcf/D; three at 20 MMcf/D; and two at 10 MMcf/D. WELLHEAD EQUIPMENT Dry desiccant dehydrators were designed to reduce the water content of the saturated wellhead stream to 2.5 lb of water/MMcf at 2,000 psig. This specification was necessary to prevent hydrates and corrosion forming in the pipeline which will operate at temperatures as low as 20F. A typical flow diagram is shown in Fig. 3, and Fig. 4 is a photograph of one of the wellhead installations. Some of the design details given below are subject to modification in the field. The well-stream flowing temperatures range from 135 to 170F. Wellhead flowing pressures up to 3,200 psig are reduced to the dehydrator-operating pressure of about 2,100 psig by throttling through a pressure control valve. The gas is then passed through an aerial cooler where its temperature is reduced to 105F. thus removing over half

By P. H. Metzger, D. W. Fuerstenau

The activation of sphalerite was found to occur at a much lower rate with Pb++ then with Cut++ or Ag+. To prevent activation with Pb++, the ratio [m in solution must approximate 103. An example is given illustrating how this condition is met in practice through the addition of zinc sulfate and soda ash. In selective lead-zinc flotation, the mill operator, especially the one who is concentrating a partially oxidized ore, often must add zinc sulfate and/or soda ash for effective depression of the sphalerite. In the present paper the authors show how this practice prevents the activation of sphalerite in the presence of Pb++. A number of years ago Gaudin (1) postulated that Zn++ might control the activation of sphalerite with Pb++ through competitive adsorption. However, recent experimentation has shown the activation of sphalerite with Ag+ and Cut++ to be a chemical reaction in which silver or copper ions replace zinc in the sphalerite lattice through the formation of a more insoluble sul-fide (2,3,4) Thus, if activation with Pb++ is similar to that with Ag+ or Cu t+, zinc salts should control the activation of sphalerite not through competitive adsorption but because the ratio of [zn++/Pb++] in solution regulates the extent of the chemical exchange between Zn++ and Pb++ in the solid phase. The objective of this investigation has been to study the kinetics and equilibrium conditions for the uptake of Pb++ by sphalerite and to investigate the prevention of lead activation with zinc salts. BASIC PRINCIPLES Sphalerite activation has been shown to be a replacement reaction wherein a less soluble compound is formed at the expense of the more soluble zinc sul-fide (2,3,4) For example, if sphalerite is placed in an aqueous silver nitrate solution, ZnS gives to the solution more S= than can exist together with Ag+, and hence the following reaction takes place: ZnS + 2 Ag+? Ag2 S + Zn ++; k = [zn ++]/[Ag ++]2 = 10 26 (1) Therefore, ZnS will dissolve in the presence of Ag+ and activation of sphalerite with Ag+ will proceed after monolayer coverage by solid state diffusion until equilibrium conditions are reached in the system (2, 4) Because of the large difference in the solubility of ZnS and Ag2S, zinc salts cannot affect the reaction unless a complexing agent, such as cyanide ions, is present to complex Ag+ more tightly than Zn++ . By complexing Ag+ and Zn++ in solution, the uptake of Ag+ by sphalerite can be regulated by controlling the ratio m. . Experimentally (2) it was found that the activation of sphalerite by Ag+ could be prevented through the addition of NaCN if this ratio reached a value of approximately 10 26. The mechanism of sphalerite activation with copper salts is given by the following reactions: ZnS + Cu ++ ? CuS + Zn + + ; (2) k = [Zn++]/[Cu++] = 10 11 ZnS + Cu + ? Cu2S+ Zn++; (3) Experimentally Mao (3) found that the activation of sphalerite with Cu++ or Cu + was prevented if the ratios expressed in Equations 2 and 3 were approximately l09 and l022, respectively, with cyanide ions as the deactivator. Although zinc salts do not affect the activation of sphalerite with silver or copper ions in the absence of a complexing agent, activation with lead ions theoretically can be controlled by the addition of zinc salts because of the relatively small differences between the solubility of ZnS and PbS (5). Equilibrium

Jan 1, 1961