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By W. C. PAGE

AS the pioneer operation treating the mixed lead- zinc-iron ores from the district tributary to the Salt Lake Valley, the International Smelting Co.'s plant has offered an extremely interesting and instructive opportunity to study some phases of this problem. Basically, there were two main reason for our attempting to work out a successful operation for the separation and concentration of the values contained in the rather widespread deposits of these so- called lead-zinc ores. In the first place, the time was ripe and demanded some method of curtailing the economic waste resulting from the costs of past and present practice of smelting ores of this character, or rather, those ores which could stand the charges inherent with smelting them. Secondly, but rather primarily with us, we believe that such a solution would greatly in- crease in general the production of lead in the district tributary to the Salt Lake Valley. It is generally known that there were and are three relatively large lead smelting plants in the Salt Lake Valley and the decreasing production of correspondingly clean lead ores was not efficient to justify the existence of all three. We could not hope for better lead smelting metallurgy nor more efficient business management than was being practised, so the only prospect was to at- tempt to work out some way to increase the primary production and thus widen the scope of operations.

Jan 1, 1926

By Edmund J. Korber, Donald E. Raab, Frank A. Burns

During the early 1960s, the advent of self- advancing longwall roof supports triggered serious consideration by Bethlehem management to introduce the technique of longwall mining at one of our central Pennsylvania coal mines. Although longwall mining was initially justified as a means to cope with the severe roof conditions at our Mine 32 (Watson, B., 1971), the result of the endeavor has been a consistent and reliable level of coal production, first from Mine 32 and then later from Mine 33, over a period of fifteen years. Longwall production from the Cambria Division has been the mainstay of the low volatile coal required by Bethlehem Steel for steel production. Let us review the events that led to this accomplishment, as well as where we stand today.

Jan 1, 1981

By E. W. Parker

THE anthracite region, from which there is produced annually about 80,000,000 tons, or approximately 15 per cent. of the total coal supply of the United States, has a combined area of a little less than 500 sq. mi. The total area occupied by the bituminous fields (including the sub-bituminous and lignite fields) is in the neighborhood of 400,000 sq. mi., so that 15 per cent. of the total output comes from this small area of only a little more than 0.1 per cent. of the coal-producing territory. of the United States. The productive anthracite area is divided into a series of basins or troughs, roughly parallel, extending. in a northeast-southwest direction through the. Counties

Jan 1, 1921

By E. W. Pehrson, J. W. Furness

THE five charts presented here- with are part of an original group prepared by the U. S. Bureau of Mines showing the international trade in the principal metals and metallic ores. Charts 011 anti- mony, chromite, copper, lead, manganese, mercury, nickel, tin, tungsten, and zinc were published in the February, 1936, issue of the Engineering and Mining Journal. Those shown here include bauxite, aluminum, iron ore, pig iron, and the platinum-group metals.

Jan 1, 1936

By Kyle Wightman

INTRODUCTION CRA Limited is the largest mining group in Australia by value of sales and the second largest company in Australia in terms of share market capitalisation. In the past 25 years, CRA, its predecessors and affiliates have been involved in a number of mining and further processing developments in Australia and elsewhere. Many of these have been financed using project financing techniques. These include Comalco's development of the Weipa bauxite deposits in Northern Queensland in the late 1950's, the Hamersley iron ore developments in the Pilbara region of Western Australia in the mid 1960's, the Queensland Alumina Limited alumina refinery in Gladstone, Queensland, at about the same time, and the Bougainville copper project in 1969/70. In the past three years CRA has again utilised project financing techniques to fund its Tarong steaming coal project in Queensland, the Blair Athol steaming coal project also in that State and CRA's interest in the Argyle diamond project in the Kimberley region of Western Austrlia. PROJECT FINANCE DEFINED Nevitt Definition Nevitt's is the most frequently quoted definition - "A financing of a particular economic unit in which a lender is satisfied to look initially to the cash flows and earnings of the economic unit as the source of funds from which a loan will be repaid and to the assets of the economic unit as collateral for the loan." Risk and Balance Sheet Treatment It is important to focus in more detail on two aspects of project financing, risk and balance sheet treatment. The assessment of the various elements of risk in a project and the sharing of that risk between sponsors and lenders is the most critical feature. At one end of the spectrum is full absorption of risk by the sponsor(s). This can be described as "on risk" or "on credit" or "full recourse" to the sponsor(s) and is effectively a corporate financing. At the other end of the spectrum the lenders absorb the whole risk in a non-recourse financing which is "off risk" or "off credit" for the sponsor. The other aspect is the sponsor's balance sheet treatment. If the balance sheet of the economic unit undertaking the project and the financing need not be consolidated into the balance sheet of the sponsor (because ownership does not exceed 50%) then the financing may be described as off-¬balance sheet. If consolidation is required then the financing is described as on-balance sheet. Most project financings involve some recourse to the sponsor, i.e. they are limited recourse. Very few are non-recourse or off credit to the sponsor. Limited recourse financings may be on-balance sheet although many may also be off-balance sheet insofar as consolidation is concerned. However, sponsor support may very well be a contingent liability to the sponsor and require disclosure by way of note to the balance sheet should consolidation not be required. CORPORATE FINANCE CONTRASTED A financing which is on credit or full recourse to the sponsor, whether it is directly borrowed or guaranteed by that sponsor, is a corporate financing. Lenders will tend to base their credit assessment on a historical assessment of the sponsor's activities and its financial results rather than an assessment of the project or a detailed assessment of the future activities and prospects of the sponsor. PROJECT FINANCE - A BORROWER'S PERCEPTION Although CRA could choose to arrange all finance on a corporate basis (except perhaps for the very largest projects or acquisitions), project financing techniques provide a number of specific advantages which CRA has noted and which should be carefully considered by a project sponsor. Advantages

Jan 1, 1985

By Leo J. Miller

It is both an honor and a pleasure for me to be the keynote speaker for the Paul F. Kerr's Symposium on Applied Mineralogy. Professor Kerr was a man for all seasons to his students, and he treated all students as distinct individuals. Philip Bethke in his memorial to Dr. Kerr summed up our remembrance best by stating that "We have lost our most successful educator-administrator-scholar, who was our steadfast teacher-counselor-mentor-friend." His unique trait was the ability to bring out the best in a variety of individuals In order that their performance was at the peak of quality.

Jan 1, 1985

By Knapp. Arthur

THE ORDINARY well log is subjected to a great deal of criticism, much of which is well founded. Sometimes, though, the difficulty in interpreting the log is due to the fact that the geologist or engineer using the logs does not know the limitations of the drilling method used. The rotary drill, especially, has inherent limitations that make it difficult, to secure .definite information at all times. The identification of well-defined key beds is about all that can be expected from the rotary log. The formation in a drilled hole, as reported by the driller; has a direct relation to the speed with which the drill makes the hole or to the reaction of the various strata on the bit, called the "feel of the bit." When this is not thoroughly understood by the geologist or engineer endeavoring to interpret the log, the result is an erroneous correlation with other wells or a discarding of the log as worthless. GENERAL TERMS Hard and Soft.-Hard and soft are relative terms. In the case of well logs, they are very misleading as they are used in connection with both resistance to abrasion and resistance to percussion. In technical rock classification, hardness is relative resistance to abrasion. The term brittleness is used in connection with resistance to blows. These terms are misleading to the geologist or engineer who is not familiar with both the cable-tool, or standard tool, method of drilling and the rotary method. In the case of the standard tools, the driller's report of the hardness of the formation is in terms of its resistance to blows. For instance, a cable-tool driller might be able to make from 30 to 50 ft. a tour in a brittle limestone, which he would call soft and at the same time he might call a relatively soft (from a purely mineralogical standpoint) gypsum hard, because it is somewhat elastic and is not readily broken by blows. The rotary driller would reverse the terms. The limestone is hard in that it resists the abrasive action of the bit, while the gypsum might be soft in that it is readily cut by the rotary bit. It is rare that wells drilled by the

Jan 2, 1920

Discussion of the paper of John H. Hall, presented at the New York. Meeting, October, 1913, and printed in Bulletin No. 79, July, 1913, pp. 1247 to 1256. WILLIAM 'R. WEBSTER, Philadelphia, Pa.:-I would like to call ,attention to the fact that the results of the ordinary tension and bend tests do not always give us the information we want even if we figure out the amount of work done. You want a bending test of sufficient width and full thickness. In the case of eyebars, for instance, I have had experience with a 10- by 1-in. eyebar which gave perfectly good results in a full-size test of the finished bar. The 10- by 1.5-in. and 10- by 1.75-in. eyebars from the same heats-of steel were absolutely worthless in full-size tests. The narrow bending tests from all these bars gave good results. Bat after going into the matter fully, we found that if pieces about 3 in. wide and full thickness were used for the. cold bending tests, the heavier material would not stand this test, but failed. That is, in order to check the quality of the rolled bar you should have a wide piece of full thickness for cold bending, as the narrow pieces give misleading results. J. E. JOHNSON, JR., New York, N. Y. :-I would like to ask if there have been any tests made to compare the results of Charpy tests with the true dynamic test similar .to the Wohler test, except that the piece is subjected to a tensile or compressive stress and to alternating stresses in addition, at the same time. This seems to me to approach more nearly than any other test to the conditions of actual service. where the piece is under a fixed initial stress plus a highly variable and often alternating stress. Some tests were made on this plan in England within a year or two. The test piece was Subjected to either a tensile or compressive stress of known amount and simultaneously to alternating stresses in addition. Such a. test as this gives information which we cannot get by a tensile test or even from the tensile strength multiplied by an. elongation. Such tests, however, are exceedingly tedious and require long periods of time in order to obtain valuable results. If material could be subjected to these dynamic tests and the same material to the. Charpy shock test, and if some reasonable qualitative relation could be established between the results of the two tests, then we could assume that the shock test, which is so simple and easy to make, was a measurably accurate test of the dynamic qualities of the material. At present it does not seem

Jan 12, 1913

By Richard L. Ash, J. H. Kelley, W. H. McCracken, William Bellano, J. D. Morgan, D. R. Mitchell

Rubber-tired shuttle cars are finding increased use as gathering units in under-ground mines. As the name implies, they shuttle back and forth between the loading machine and the section transportation system. In many mines their use has in-creased the efficiency of the loading and gathering operations, resulting in increased output per man employed and decreased costs per ton. A car motivated by cable reel is shown in Fig I, and a car with battery power in Fig 2. A brief chronological account of the development of rubber-tired haulage equip-ment follows: 1936. J. H. Fletcher1 installed his first unit for the Blue Bird Coal Co., Carrier Mills, Illinois. This unit consisted of a battery-powered industrial tractor and a trailer with drop-bottom doors. The coal was transported for short distances to a hopper for discharge into mine cars. 1938. A battery-powered self-contained shut-tle car with rubber-tired wheels was built by the Joy Manufacturing Co. Two units were installed for the Katherine Coal Co., Lumberport, West Virginia. The shuttle car consisted of a materials-receiving body with a conveyor in the bottom to move the coal forward during loading and to unload the coal at the discharge station. 1938. A cable-powered shuttle car with four-wheel drive and four-wheel steer was developed by A. L. Lee. Special wheels mounted on king pins on the car permitted all four wheels to be steered. The cable reel was driven by a torque motor to give the cable proper tension during the payout and uniform tension when rewound on the reel. 1940. A Joy shuttle car equipped with trolley poles and a cable reel was developed to operate on a double trolley-wire system.2 This unit was installed at a potash mine of the International Minerals and Chemicals Corporation at Carlsbad, New Mexico. It is believed to have been the first installation of its kind, and the first of shuttle cars for handling material other than coal. 1941. Truck haulage3 was introduced in the Tri State District by the Eagle-Picher Mining and Smelting Company. Storage battery electric trucks were rebuilt to handle a bottom-dump trailer. 1941—Joy shuttle cars were installed in a mine of the United States Gypsum Company, Oakfield, New York. 1943—Joy shuttle cars were installed in several bauxite mines.4,5 1945—Joy shuttle cars installed in a lime-stone mine. Because of the nature of bituminous coal beds trackless equipment has had its greatest application in bituminous coal mining. Usually a shuttle car is filled by a continuous type of loader. In Fig 3 is shown a continuous machine loading coal into a battery-powered shuttle car, 48-in. coal. However, intermittent types of load-

Jan 1, 1949

By R. S. French

The purpose of this paper is to present data that have been obtained during the past two years concerning the effects of prior cold-work and temperature and time of anneal upon the recrystallization and grain growth of 70-30 cartridge brass. It was desirable to study certain of these phases so that an accurate picture of the principles of the subject could be shown. The work is not intended to provide explicit annealing data, but to provide material examples that may help to clarify analogous problems concerning this alloy. Specifications often set limitations upon the grain size of annealed materials because of the importance of grain size upon subsequent manufacturing operations. It was, therefore, worth while to study the variables that affect the recrystallized grain size of this material. C. H. Mathewson and A. Phillips,l W. R, Webster,2 and others have presented annealing characteristic curves of this alloy. A recent typical curve presented by R. S. Pratt3 is shown in Fig. I. The tensile properties and grain sizes are shown as functions of the annealing temperature. Such curves serve as a useful guide in determining the physical properties of annealed material, but as they are made generally under carefully controlled laboratory conditions they do not indicate the performance of metal annealed in a mill muffle, where such conditions as amounts of metal, heating time and temperature may differ. Study of the effect of time and temperature upon grain growth and subscquent recrystallization was made with a coil of metal having the following analysis: 70.04 per cent copper; 0.007 lead; 0.007 iron; 0.00 tin; 0.00 silicon; 0.001 nickel; 0.000 phosphorus; balance zinc. The sample coil was obtained from metal that had been rerolled from hot-rolled mill stock, and was received at 0.228-in. gauge, soft, with a grain size of 0.125 mm. This material was then rolled 43.5 per cent to 0.129-in. gauge and annealed to a 0.053-mm. grain size. In this condition, samples were cut and used in all of the experimental work reported in this paper. Time The first study was of crystal growth at a constant temperature over a moderate length of time. Material was cut from the stock coil at 0.129-in. size and rolled 75 per , cent hard to 0.032-in. gauge. From this piece small samples were cut M by 2 in., suitable for grain-size determina.tions. Twelve samples were placed in an electric furnace uniformly across the width, approximately an inch from the floor. A thermocouple was wired to the center sample, so that the approximate metal temperature could be followed. At various

Jan 1, 1944

By R. S. French

The purpose of this paper is to present data that have been obtained during the past two years concerning the effects of prior cold-work and temperature and time of anneal upon the recrystallization and grain growth of 70-30 cartridge brass. It was desirable to study certain of these phases so that an accurate picture of the principles of the subject could be shown. The work is not intended to provide explicit annealing data, but to provide material examples that may help to clarify analogous problems concerning this alloy. Specifications often set limitations upon the grain size of annealed materials because of the importance of grain size upon subsequent manufacturing operations. It was, therefore, worth while to study the variables that affect the recrystallized grain size of this material. C. H. Mathewson and A. Phillips,l W. R, Webster,2 and others have presented annealing characteristic curves of this alloy. A recent typical curve presented by R. S. Pratt3 is shown in Fig. I. The tensile properties and grain sizes are shown as functions of the annealing temperature. Such curves serve as a useful guide in determining the physical properties of annealed material, but as they are made generally under carefully controlled laboratory conditions they do not indicate the performance of metal annealed in a mill muffle, where such conditions as amounts of metal, heating time and temperature may differ. Study of the effect of time and temperature upon grain growth and subscquent recrystallization was made with a coil of metal having the following analysis: 70.04 per cent copper; 0.007 lead; 0.007 iron; 0.00 tin; 0.00 silicon; 0.001 nickel; 0.000 phosphorus; balance zinc. The sample coil was obtained from metal that had been rerolled from hot-rolled mill stock, and was received at 0.228-in. gauge, soft, with a grain size of 0.125 mm. This material was then rolled 43.5 per cent to 0.129-in. gauge and annealed to a 0.053-mm. grain size. In this condition, samples were cut and used in all of the experimental work reported in this paper. Time The first study was of crystal growth at a constant temperature over a moderate length of time. Material was cut from the stock coil at 0.129-in. size and rolled 75 per , cent hard to 0.032-in. gauge. From this piece small samples were cut M by 2 in., suitable for grain-size determina.tions. Twelve samples were placed in an electric furnace uniformly across the width, approximately an inch from the floor. A thermocouple was wired to the center sample, so that the approximate metal temperature could be followed. At various

Jan 1, 1944

By R. S. French

THE purpose of this paper is to present data that have been obtained during the past two years concerning the effects of prior cold-work and temperature and time of anneal upon the recrystallization and grain growth of 70-30 cartridge brass. It was desirable to study certain of these phases so that an accurate picture of the principles of the subject could be shown. The work is not intended to provide explicit annealing data, but to provide material examples that may help to clarify analogous problems concerning this alloy. Specifications often set limitations upon the grain size of annealed materials because of the importance of grain size upon subsequent manufacturing operations. It was, therefore, worth while to study the variables that affect the recrystallized grain size of this material. C. H. Mathewson and A. Phillips,1 W. R. Webster,2 and others have presented annealing characteristic curves of this alloy. A recent typical curve presented by R. S. Pratt3 is shown in Fig. I. The tensile properties and grain sizes are shown as functions of the annealing temperature. Such curves serve as a useful guide in determining the physical properties of annealed material, but as they are made generally under carefully controlled laboratory conditions they do not indicate the performance of metal annealed in a mill muffle, where conditions are different and the amounts of metal require necessarily longer heating times and temperatures. Study of the effect of time and temperature upon grain growth and subsequent recrystallization was made with a coil of metal having the following analysis: 70.04 per cent copper; 0.007 lead; 0.007 iron; 0.00 tin; 0.00 silicon; 0.001 nickel; 0.000 phosphorus; balance zinc. The sample coil was obtained from metal that had been rerolled from hot-rolled mill stock, and was received at 0.228-in. gauge, soft, with a grain size of 0.125 mm. This material was then rolled 43.5 per cent to 0.125-in. gauge and annealed to a 0.053-mm. grain size. In this condition, samples were cut and used in all of the experimental work reported in this paper. TIME The first study was of crystal growth at a constant temperature over a moderate length of time. Material was cut from the stock coil at 0.129-in. size and rolled 75 per cent hard to 0.032-in. gauge. From this piece small samples were cut ½ by 2 in., suitable for grain-size determinations. Twelve samples were placed in an electric furnace uniformly across the width, approximately an inch from the floor, A thermocouple was wired to the center sample, so that the approximate metal temperature could be followed. At various

Jan 1, 1944

Discussion of the paper of C. W. WASHBURNE, presented at the Pittsburgh meeting, October, 1914, and printed in Bulletin No. 93,. September, 1914, pp. 2365 to 2378. ROSWELL H. JOHNSON, Pittsburgh, Pa.-It seems to me rather important to bear in mind one thing which is sometimes lost sight of, that the marine sedimentary rocks are laid down in water. We have to start with an initial charge of water. That being so, and the surface tension between the water and the -oil being as slight as it is, as referred to by Mr. Washburne,. the phenomena of capillarity are bound to be most important as between the liquid surface and the gas surface. So far as the liquid-gas surface is concerned, capillarity, in my opinion, is of the utmost importance, and it seems to me this paper of Mr. Washburne's is of great value to us for that reason. Starting out as we have, with our attention concentrated upon gravitational sorting, we have had to wait for the discussion of movement furnished by Munn, and this discussion of capillarity by Washburne, for a more balanced view of the situation. It seems to me that in the accumulation of oil and gas we have a problem of the interworking of gravitational sorting, capillarity, viscosity, immiscibility, and movement. All five things seem to me to be important. I would have expected Mr. Washburne to have given a fuller treatment of the relation of movement to capillarity. In my own experiments I find that gravitation and capillarity alone seem remarkably impotent when everything is at rest, but if I furnish a little movement, gravitation and capillarity step in and accomplish a great many results that one would not expect. Take a horizontal tube and fill a portion at the middle with an ordinary sand saturated with oil, and then put water and sand in each end, and the tube may remain at rest a very long time without that oil distributing itself along the top of the tube. But with a little motion that oil will gradually work up to the upper side. So gravitation and capillarity alone are rather impotent unless they get this element of movement. It would not be necessary to have very extensive movement, but some degree of movement is essential. Now if natural gas, in addition to the method of origin by the action of bacteria on organic matter in mud, may also arise by pressure at great depth, as the overburden is added, a great deal of motion may result. I think more motion is produced in this way than by the descent of meteoric waters.

Jan 4, 1915

By R. P. Smith

Iron-carbon alloys containing a single-phase austenite region and a two-phase azcstenite + cementite region at the desired temperature were prepared by partial carburization of iron or partial decarburization of carburized iron. Each sample was held at a fixed temperature until equilibrium was achieved. Analysis of the austenite for carbon then gave the solubility of cementite in austenite. Solubility measzcrements were made for the temperature range 734° to 1012°C. These values together with other data give 7560 cal for the mean heat of solution of cementite in austenite, and 0.765 pct C for the eutectoid composition of austenite. They also indicate that graphite is the stable phase at all temperatures between the eutectoid and eutectic temperature. Measurements of the solubility of cementite in austenite at 927oand 1011 "C, using a method based on the equilibration of iron with boro-cementites, are reported. The solubility of cementite in austenite (?-iron) has been computed by Darken and Gurry1 from the observed solubility of graphite in austenite, and the thermodynamic properties of pure iron and of iron-carbon alloys. They have shown that the solubility of cementite is greater than that of graphite in the temperature range between the eutectoid and eutectic, and thus that cementite is metastable with respect to graphite and austenite saturated therewith. Since their computation is not in accord with the earlier experimental work of Mehl and wells,' the present direct determination of the solubility of cementite in austenite was undertaken. EXPERIMENTAL PROCEDURE Each iron rod about 1/2 in. O.D. by 4 in. was first carburized at a temperature and with a H2-CH4 gas mixture such that the carbon content would be greater than that corresponding to the solubility of cementite in austenite at the desired (lower) temperature; sufficient carburizing time was allowed that the carbon content became substantially uniform, as illustrated by Curve A, Fig. 1. The sample was then partially decarburized with a hydrogen-water vapor mixture, giving a carbon distribution as schematically illustrated by Curve B. The sample was then held in a helium atmosphere at the temperature at which the solubility was to be determined until the decarburized portion of the sample came to equilibrium with that containing cementite. Curve C of Fig. 1 represents schematically the final carbon distribution; the horizontal portion corresponds to the carbon content of austenite saturated with cementite. To bring the sample to room temperature without change in the carbon distribution and in machinable condition, it was first quenched in a salt pot at 480°C, then in water at room temperature. Successive layers were machined from the center 2 in. of the sample and analyzed for carbon by the usual

Jan 1, 1960

By T. H. Dunn, P. L. Menaul

This paper discusses the results of an investigation made to develop a method of combatting corrosion of subsurface oil-well equipment caused by brines containing hydrogen sulphide. Carbon monoxide, aldehydes, and certain cyanide compounds were found by laboratory tests to effectively inhibit corrosion of steel by sulphide brines. Experiments were made for one year in eight wells in West Texas fields using formaldehyde as an inhibitor. It was found that the inhibitor treatment successfully prevented the severe corrosion previously experienced in these wells, and effected important net savings in operating costs. Introduction Corrosion of oil-field equipment has long been a problem in areas producing sour crudes. These areas include the major fields of Arkansas, Western Kansas, West Texas and New Mexico. Corrosion in these fields is caused primarily by the chemical action of hydrogen sulphide in the presence of water and by electric currents entering the wells through flow lines. Hydrogen sulphide is noncorrosive to iron or steel in the absence of water but under the usual conditions prevailing in oil wells where more or less water is present, hydrogen sulphide is very corrosive. This type of corrosion occurs over the pH range below 9, which includes all natural oil-field brines. If air is present in addition to hydrogen sulphide and water, corrosion proceeds at an extremely rapid rate. It was reported several years ago that a string of oil-well tubing was literally dissolved within 50 days where an air lift was used on a well producing considerable water and hydrogen sulphide. Air is generally absent in wells producing sour crude. After hydrogen sulphide corrosion starts, it proceeds with increasing severity and its correction becomes progressively more difficult. This characteristic of sulphide corrosion has been attributed to the formation of galvanic couples between the iron and steel equipment on one hand and the products of corrosion on the other.' Severe corrosion of subsurface oil-well equipment leads to a multitude of troubles. In addition to destruction of costly equipment, producing sands often are damaged by flooding with water leaking through corroded casing; bad mechanical conditions may develop in a well due to obstructions caused by corroded equipment lost in the hole, or partly collapsed casing; pumping operations are interfered with, and severe emulsification problems may result from the homogenizing action of corroded balls and seats.% A typical case of severe corrosion caused by hydrogen sulphide was reported in Howard County, Texas, where it was necessary to pull tubing once a week to repair leaks after the tubing had been in use for only one year. On one well in this area a string of tubing was pulled 11 times in 8 months; 11 joints of tubing being replaced because of leaks. In Ector

Jan 1, 1946

By T. H. Dunn, P. L. Menaul

This paper discusses the results of an investigation made to develop a method of combatting corrosion of subsurface oil-well equipment caused by brines containing hydrogen sulphide. Carbon monoxide, aldehydes, and certain cyanide compounds were found by laboratory tests to effectively inhibit corrosion of steel by sulphide brines. Experiments were made for one year in eight wells in West Texas fields using formaldehyde as an inhibitor. It was found that the inhibitor treatment successfully prevented the severe corrosion previously experienced in these wells, and effected important net savings in operating costs. Introduction Corrosion of oil-field equipment has long been a problem in areas producing sour crudes. These areas include the major fields of Arkansas, Western Kansas, West Texas and New Mexico. Corrosion in these fields is caused primarily by the chemical action of hydrogen sulphide in the presence of water and by electric currents entering the wells through flow lines. Hydrogen sulphide is noncorrosive to iron or steel in the absence of water but under the usual conditions prevailing in oil wells where more or less water is present, hydrogen sulphide is very corrosive. This type of corrosion occurs over the pH range below 9, which includes all natural oil-field brines. If air is present in addition to hydrogen sulphide and water, corrosion proceeds at an extremely rapid rate. It was reported several years ago that a string of oil-well tubing was literally dissolved within 50 days where an air lift was used on a well producing considerable water and hydrogen sulphide. Air is generally absent in wells producing sour crude. After hydrogen sulphide corrosion starts, it proceeds with increasing severity and its correction becomes progressively more difficult. This characteristic of sulphide corrosion has been attributed to the formation of galvanic couples between the iron and steel equipment on one hand and the products of corrosion on the other.' Severe corrosion of subsurface oil-well equipment leads to a multitude of troubles. In addition to destruction of costly equipment, producing sands often are damaged by flooding with water leaking through corroded casing; bad mechanical conditions may develop in a well due to obstructions caused by corroded equipment lost in the hole, or partly collapsed casing; pumping operations are interfered with, and severe emulsification problems may result from the homogenizing action of corroded balls and seats.% A typical case of severe corrosion caused by hydrogen sulphide was reported in Howard County, Texas, where it was necessary to pull tubing once a week to repair leaks after the tubing had been in use for only one year. On one well in this area a string of tubing was pulled 11 times in 8 months; 11 joints of tubing being replaced because of leaks. In Ector

Jan 1, 1946

The Hadsel Mill. By R. G HALL (Trans, vol 112 4000 words) This mill is designed to effect the entire reduction of ores by combined crushing and grinding from mine run size to material sufficiently fine for the usual operation of flotation or cyaniding The work is begun and completed in the same machine. The machine is designed on the principal of the elevator wheel, and crushing and grinding are accomplished by dropping a mixture of ore and water upon specially placed "breaker plates" in such a manner that the resultant material passes back into the buckets of the wheel for further elevation One method of removal of the finished product is to permit an overflow of wet pulp on one side of the mill through coarse screens A recent improvement provides for the removal of a pulp by a launder part way up the path of the buckets In either case the pulp passes to a classifier, and the oversize back to the mill in the manner familiar in ball-mill practice Although hardly through the development stage, the machine has given a very good account of itself in simplification of plant, by elimination of coarse and fine crushers with consequent reduction of installation cost and power consumption As compared with the ball mill alone, there is a reduction of power consumption as well as a material reduction of grinding steel There is an increase in cost of maintenance other than grinding steel, but as the machine passes out of the development stage there is a show¬ing of reduction of costs on this item It seems probable that with further develop¬ment and strengthening of the weaker parts further improvement may be made Ball Milling. By A. M Gow, M GUGGENHEIM, A. B. CAMPBELL AND W. H COGHILL. (Tech Pub 517; also Trans, vol 112. 24,000 words) This paper outlines a new philosophy in ball milling by using power as an index of mill operation and ascertaining the effects of the set and induced variables By recognizing the amount of ore in the mill as an important induced variable and recognizing that the amount of ore in the mill depends principally on the size of the discharge trunnion, ball volume, rate of feed, and speed of mill, obstacles formerly met were surmounted When the amount of ore in the mill is dealt with intelligently and the applied work is proportional to the amount of feed, series testing, which would otherwise give a hotchpotch, gives concordant results The study of ball paths and trajectories was seen to be fruitless when it was shown that the old attrition theory for slow mill speed

Jan 1, 1935

By A. A. Smith, J. S. Smart

THE controlled amounts of phosphorus, arsenic, sulphur or selenium found in commercial coppers perform a variety of highly useful functions. Indeed, a large segment of modem copper technology is essentially dependent upon the presence of one or more of these elements. Consequently, the literature contains many references to their effects but the scope is broad and has been only partly covered. New data are presented herewith directed toward a better understanding of the basic behavior of these elements in copper, with particular emphasis on the composition range 0 to 0.05 per cent. These data are a part of a general program of research on the effects of impurities on the properties of oxygen-bearing and oxygen-free copper, other portions of which have been reported previously.1-2-3 Schematically, the behavior of individual elements is determined from measurements of conductivity and softening temperature,1, 2 and the binary alloys employed are synthesized from high-purity copper in order to eliminate interference from the effects of extraneous impurities. Alloys of selected composition were first prepared in the oxygen-free form by continuously casting the melts in the form of 3/8-in. diameter rod. Oxygen was added subsequently to portions of the alloys, either by remelting or by diffusion at 850°C. from a surface scale. Test wires were drawn one B. and S. number per pass, using four 30-min. 600°C. anneals at o.3125, 0.257, o.204 and o.162 in., and a final cold reduction of 95 per cent t0 0.081 in. Oxygen-bearing slugs made by remelting were hot-rolled to 5/16 in., drawn to 0.162 in., annealed for 30 min. at 600°C. and cold-drawn 95 per cent to 0.081inch. The alloys containing phosphorus, having been compounded very early in the program, were prepared in the form of 5/16-in. rod, and processed to wire with only the last three intermediate anneals listed above, all of these having been conducted in commercial nitrogen. In addition, the conductivity anneals on these alloys were also performed in the same atmosphere, and the small amount of oxygen present as an impurity in the gas resulted in some loss of accuracy at temperatures of 700° to 800°C., as will be shown later. Subsequently, the anneals for all oxygen-free alloys were conducted in hydrogen to prevent oxidation, and purified nitrogen was employed only for oxygen-bearing samples. All conductivity anneals were of one hour duration followed by a rapid quench in 10 per cent H2SO4. EFFECT OF PHOSPHORUS The widespread use of phosphorus as a deoxidant has resulted in universal appreci-

Jan 1, 1945

By W. A. Backofen, D. Lee, F. S. Jabara

THE empirical character of plasticity analysis insures a continuing need for measurements of the yield surfaces of anisotropic materials. Recently, Wheeler and Ireland (W-I) proposed that an octahedral yield locus could be constructed on the basis of six Knoop hardness indentations. Such simplicity would have obvious appeal, if it led to consistently dependable results. In other recent work, a much more straightforward (and more tedious) method of measurement was used to establish all quadrants of the plane-stress yield loci for two substantially anisotropic titanium alloys.2,3 The same materials have since been reex-amined by the W-I method with results being reported here. A full description of the stress state under a Knoop indentor would be complex. In principle, however, this can be avoided in relating the hardness number to a plane-stress yield locus, by the expedient of superimposing the appropriate hydrostatic component on that state of stress. Six possible orientations of in-dentor on orthogonal (symmetry) planes, along (principal) coordinate directions, are illustrated in Fig. 1(0). Pictured in Fig. l(b) are normal-stress components nominally associated with indentation n: o2(H), directly proportional to the Khn in this case, together with By overlaying a hydrostatic tension, ah, that in general is equal to the stress state around the indentation is reduced to one of plane stress in the x-y plane for which the stress ratio is a The key step in the W-I yield-locus construction is to represent the Khn for any indentor orientation as a vector quantity on the octahedral plane. In the plotting, the vector is given as deviatoric stress components along the principal axes in the ratio , where represents the direction of the minor (width) diagonal and 1 that of the major (length) diagonal. There is no attempt by W-I to justify the 7/1, although it might be supposed that the value originates in the usual ratio of major to minor diagonals in a Knoop indentation of about 7/1. If that were its origin, the link to the deviatoric stress ratio would presumably be made by first taking 7/1 and then turning to the Levy-Mises equation for isotropic material: Interpreted in this way, the W-1 approach seems arbitrary and even contradictory. Yet it would still be favored by two circumstances: the deformation under a Knoop indentor approaches plane strain: when dcw/del =a; and the shape of the locus where plane strain is represented is not overly sensitive either to the exact value of dc,/dcl or to the degree of anisotropy, within a rather wide range of both variables. The second point is illustrated below, after a few additional comments on applying hardness

Jan 1, 1968

(The paper by L. H. De Wald-Tech. Pub. No. 429 was presented at the Boston meeting, September, 1931.) W. A. SCHEUCH, Chicago, Ill.-Since starting up our Hawthorne copper wire plant we have found that wire bars from certain suppliers perform quite differently from those of other suppliers. In attempting to evaluate these bars, we made cross-sections, and in making these cross-sections we found considerable variation in the crystal structure. Indications were that there was some preference in the type of crystal structure. In attempting to find the reason for that we discussed it with the various producers and-also reviewed the literature. Mr. DeWald was assigned to determine the various factors that enter into copper wire bar crystal structure, on the basis that the product was a horizontally cast wire bar of practically identical composition and of recognized good composition for the present quality product sold in the market. Mr. DeWald has asked me to say that he should have made reference to Mr. Dalzell's paper on a theory concerning gases in refined copper. D. K. CRAMPTON, Marion, Conn. (written discussion).-Mr. DeWald has set forth an interesting and thorough exposition of the factors controlling macrostructure of this material. It is particularly interesting to us as it somewhat parallels work we have done on macrostructure of round copper billets for piercing into tubes. Our findings as to the effect of the several variables on macrostructure check Mr. DeWald's. The general principles underlying the two are precisely the same. The fact that we worked with copper deoxidized with phosphorous instead of tough-pitch copper, and round billets cast on end instead of wire bars, does not influence the results. We have found that round billets cast so as to produce large radial grains have greater soundness and density than those with a fine macrostructure. Further, and more important, we have found that the billets with large radial grains show markedly different performance on piercing from those having a fine equiaxed structure. With a given temperature of billet and adjustment of piercing machine, the coarse-grained material requires appreciably lower power for piercing and goes through the operation inn appreciably less time. These two differences are of sufficient commercial importance to warrant exercise of great care in maintaining the coarse structure. It seems probable that much the same phenomenon should hold in the hot rolling of tough-pitch wire bars. We would expect that, other things being equal, the coarse-grained wire bars would roll more readily and require less power than fine-grained ones. Moreover, we believe the differences in initial structure of the wire bars should be largely eliminated in the hot rolling process and during the subsequent drawing and annealing, of wire would be entirely eradicated.

Jan 1, 1932