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By AIME AIME

THE non-ferrous 'metals industry of the Soviet Union found itself in a very low position at the beginning of the reconstruction period in 1922, due to the absence of modern smelters and the run-down condition of the existing ones. Up to. 1924 there was no great demand for newly smelted non-ferrous metals due to the considerable stocks' of copper, zinc, lead, tin and aluminum in the courtry and also to the undeveloped condition of Soviet industries. However, in 1925 it became necessary to obtain new stocks of non-ferrous metals and in that year 12,000 tons of zinc, 14,000 tons of lead and 2,000 tons of tin and aluminum were imported into the U. S. S. R.

Jan 1, 1929

By AIME AIME

LEWIS EMANUEL YOUNG was elected a Director of the A.I.M.E. at the last Annual Meeting as a representative of District '4, including. Ohio, West Virginia, and western. Pennsylvania and New York. He also represents the Coal Division, in which industry lie has actively participated- for nearly twenty years. Dr. Young was horn in Topeka, Kan., Oct. 1, 1873, received mining degrees from Penn State and ,-Iowa. State, and a Ph.D., from Illinois. The first part of his professional life was spent in teaching first as instructor in mining at Iowa State, second .as professor of mining at the Colorado School' of Mines, third as director of the School of Mines and Metallurgy at Rolla, Mo., and finally he taught business

Jan 1, 1937

By K. H. G. Ashbee, J. W. Heavens

One consequence of the distribution in orientation of Bragg diffracting planes in an elastically bent foil is that simultaneous diffraction occurs from ±g pairs, where g is the reciprocal lattice vector to a diffracting plane. If such Bragg contour pairs are indexed, then the variation in orientation with respect to the incident electron beam is known. This note describes a construction by means of which Bragg contour pairs may be indexed by inspection. Referring to Fig. 1, the Ewald sphere radius is l/h, where is the wavelength of the electron beam, and the half spacing of first-order reciprocal lattice planes is l/d, where d is the corresponding spacing in direct space. The angle subtended by the zero and first-order planes at the center of the Ewald sphere is a = sin-' Thus, to represent a pair of first-order Bragg contours on a stereographic projection, measure ±a from, and along the normal to, the zero-order plane. The traces of the required Bragg contours pass through these points and parallel to the zero-order trace. In practice, it is desirable to enlarge a stereographic projection of the zero-order planes before making the construction. As an example, a stereographic projection of first-order Bragg contours up to line 27 for an fcc crystal is given in Fig. 2; if required, higher-order contours can easily be added. Fig. 2 is, of course, a map of first-order Brillouin zone boundaries. One use of this construction is the measurement of large elastic fields in electron microscope specimens. Fig. 3(a) shows a pattern of Bragg contour pairs due to lattice distortions near a large precipitate. This particular example is of a T-phase precipitate in Hidu-minium 54 (A1 + 6 wt pct Cu, 0.5 wt pct Mn). Foil buckling is produced by annealing during observation and may be evidence for evaporation from the precipitate.' Comparing Figs. 2 and 3(0), it is evident that the axis of high symmetry in Fig. 3(a) is [lll]. The strain in a bent foil is approxinlately t/2r, where / is the foil thickness and ? the radius to which the foil is bent. From the projections of grain boundaries and of helical dislocations, it was estimated that ( - 3000A, and values for ? were obtained from the

Jan 1, 1968

By D. J. Carney, J. Chipman, N. J. Grant

SINCE the beginning of this century it has been known that hydrogen contributes to the porosity of steel and that it is harmful to its mechanical properties. The evidence for this has been largely qualitative. Steel to which hydrogen was purposely added. in sufficient .amounts was shown to be either porous or brittle or both, whereas similar steel of low hydrogen content was shown to be free of porosity and to possess normal physical properties. There have been a considerable number of qualitative experiments of this type. Also, early in this century, a few attempts were made to measure the amount of hydrogen normally dissolved in commercial steels. This was usually done by placing the sample under an inverted liquid column such as mercury and collecting the evolved gas. These attempts, while not successful in measuring actual amounts of dissolved hydrogen gas, were able to prove that this gas will diffuse out of steel at room temperature, and that the amount of hydrogen dissolved is normally very small. On the basis of such qualitative evidence, hydrogen has been and still is blamed for a great number of the troubles encountered in the steel industry. In recent years, partial solutions for many steel-working problems have been obtained. These have led to increased interest in accurate quantitative work on hydrogen in steel, with the expectation that the results might possibly answer a few of the remaining unsolved problems. Commercially, two of the obvious questions which are in need of an answer are: (1) what are the most important sources of hydrogen, and (2) what quantity of hydrogen can be tolerated in various steels? There are many other unanswered questions. To begin to find the answers it seemed logical to start at the beginning of steel production with the liquid metal. Further, it seemed almost imperative to solve first the problems of analysis and sampling of the metal for hydrogen. Once these problems have been solved, it would be possible to answer more of the important commercial problems mentioned above. As a consequence, it was decided to design an analytical apparatus and, upon satisfactory completion of this, to develop an accurate method of sampling liquid metal for hydrogen.

Jan 1, 1951

By N. H. Murlenberg, T. M. Drown

It is often a tedious matter to get a solution of pig iron or steel, for the determination of phosphorus, which is absolutely free from silica. Where pig iron rich in silicon is dissolved in hydrochloric or nitric acid in the usual procedure, it is necessary, not only to evaporate the solution to complete dry ness, but to heat the dry residue for some beam in an air-bath to a temperature of about 120° C. The oxide of iron is thus rendered insoluble in nitric acid, and is only slowly dissolved by hydrochloric acid. In the method of determining silicon by nitric and sulphuric acid, described in the Transactions of the Institute, Vol. VII, page 346, arid Vol. VIII, page 508, we obtain in one or two hours a solution of the iron in the form of ferric sulphate entirely free from silica, and containing free sulphuric acid. It occurred to Us that this solution might be made available for the determination of the phosphorus by the molybdate method. The following experiments mere tried with unsatisfactory results. 1st. The iron was precipitated by ammonia, the precipitate filtered, washed, and dissolved in nitric acid. 2d. The iron was precipitated as basic acetate and dissolved in nitric acid. 3d. The solution was neutralized by ammonia, and nitric acid added in small excess. In all these cases the phosphorus obtained by precipitating by ammonium molybdate and magnesia-mixture was too low. The following method was then tried with success. The filtrate from the silica and graphite was evaporated to small bulk and heated in a porcelain dish on a sand-bath. until fumes of sulphuric acid ceased to escape. The dry residue was taken up with dilute nitric acid and the solution precipitated by ammonium molyldate. The phosphorus was weighed as magnesium pyrophosphate. The results were satisfactory. To save time, the original solution of the iron in nitric and sulphuric acids was evaporated to dryness and heated as before until

Jan 1, 1882

By C. M. Nickerson

The possibility of deeper production in the Buena Vista Hills was first considered in 1933. At that time, however, the heavy state curtailment program served to deter any operator from drilling test wells, which, if successful, might upset the proration schedules. Because most of the acreage was held by several major operators and the remainder by substantial independents, the adoption of a plan of cooperative development was considered desirable. Such a plan was formulated for the development of any deeper oil and gas horizons that may be found to exist. This plan, which was signed by the Secretaries of the Navy and of the Interior on behalf of the United States on July 9,1936, is now effective for the development of lands within the area shown on Fig. 1. Unlike most unit plans, the present cooperative development plan permits each operator to drill and produce his own wells. For the purpose of this plan the Buena Vista Hills field is divided into two pools. The present production is classed as the " old pool,"' while any future production below a certain marker which roughly coincides with the bottom of the Santa Margarita formation is included in the "pool" to which the provisions particularly apply. Naval Petroleum Reserve No. 2 lies within the area and constitutes the major portion of the Federal leases subject to the plan. There are 39,040 acres and 27 operators within the area. Twenty-six operators controlling 99.5 per cent of the acreage have signed the agreement. Geology oF the Buena Vista Hills The Buena Vista Hills consist of a low range in the southern portion of the San Joaquin Valley, and are roughly parallel to the adjacent Temblor range to the south. The Elk Hills oil field parallels the Buena Vista Hills a few miles to the north. The subsurface structure is a re-entrant anticline upon the major Midway-Sunset monocline. This anticline is divided into two minor

Jan 1, 1937

By Simon T. Johnson

Potential applications for boom tunnelling machines requires reliable assessment of in-situ performance. The majority of existing classification schemes concentrate on the prediction of excavation rate, neglecting the important influence of tool consumption rates. A statistical approach is taken to the analysis of the performance data, which was obtained first-hand through in-situ monitoring, and laboratory testing of representative rock samples. A statistical discrimination technique is used to produce a scheme for the prediction of performance groups, each of which covers a limited range of cutting rate and/or tool consumption rate.

Jan 1, 1984

By R. B. Gilmore

The North Texas district, as herein defined, includes the counties of Archer, Baylor, Clay, Cooke, Foard, Hardeman, Jack, Kiiox, Montague, Wichita, Wil-barger, and Young. Jack and Young Counties are included for the first time so that this district will correspond with District No. 9 of the Texas Railroad Commission. This area covers generally the crest and south flank of a system of buried mountains known as the Red River uplift. The oil and gas accumulations along this feature are in traps, which, although localized by structures incident to the regional uplift, usually are modified by stratigraphic changes in the sediments. The structural deformation caused by the Red River uplift is modified by the Rend arch, which is a broad anticline plunging northward from the Llano uplift in central Texas through Young and into Archer Counties. The fields in southern Archer, southeastern Baylor, southwestern Clay, and western Jack Counties arc on the extreme north end and along the flanks of the Bend arch and have generally the same type of oil and gas accumulation as the other fields in this district. Recent exploration has been along the flanks of the Fort Worth syncline, which is east of the Bend arch and south of the Red River uplift and extends into southeastern Clay and southwestern Montague Counties and along the eastern part of Jack County. The larger part of past oil and gas produc- tion has come from Pennsylvanian strata, with less important amounts lrom the Permian, and minor quantities from the Mississippian and Ordovician. Developments during 1943 About 1100 wells were drilled in the district during 1943 and more than 500 oil wells were completed, an increase from 1942. of approximately 12 per cent in the number of successful drilling operations of the total wells drilled. The addition of Jack and Young Counties to this district accounts for part of this increase, almost 150 wells being completed in the two counties. Production increased slightly over the previous year as a result of an increase in the number of producing wells and a greater demand for this high-gravity, sweet crude oil. The average depth of discovery wells was about 400 ft. deeper than in 1942. Although more discoveries produced from horizons below the base of the Strawn series than from those above the Straw, the deeper horizons, including the Bend series of the Pennsylvanian, the Mississippian limestone and Ellenburger of the Ordo-vician, largely were dissappointing from the viewpoint of major additions to oil reserves. The largest single addition to the reserves was in the basal Strawn sand in the Walnut Bend field, Cooke County. During the year, 31 wells were completed, both in the field and as cxtensions. The most active arca Was Jack County, in which five fields or potential fields were discovered, although only 44 oil wells were completed.

Jan 1, 1944

By R. B. Gilmore

The North Texas district, as herein defined, includes the counties of Archer, Baylor, Clay, Cooke, Foard, Hardeman, Jack, Kiiox, Montague, Wichita, Wil-barger, and Young. Jack and Young Counties are included for the first time so that this district will correspond with District No. 9 of the Texas Railroad Commission. This area covers generally the crest and south flank of a system of buried mountains known as the Red River uplift. The oil and gas accumulations along this feature are in traps, which, although localized by structures incident to the regional uplift, usually are modified by stratigraphic changes in the sediments. The structural deformation caused by the Red River uplift is modified by the Rend arch, which is a broad anticline plunging northward from the Llano uplift in central Texas through Young and into Archer Counties. The fields in southern Archer, southeastern Baylor, southwestern Clay, and western Jack Counties arc on the extreme north end and along the flanks of the Bend arch and have generally the same type of oil and gas accumulation as the other fields in this district. Recent exploration has been along the flanks of the Fort Worth syncline, which is east of the Bend arch and south of the Red River uplift and extends into southeastern Clay and southwestern Montague Counties and along the eastern part of Jack County. The larger part of past oil and gas produc- tion has come from Pennsylvanian strata, with less important amounts lrom the Permian, and minor quantities from the Mississippian and Ordovician. Developments during 1943 About 1100 wells were drilled in the district during 1943 and more than 500 oil wells were completed, an increase from 1942. of approximately 12 per cent in the number of successful drilling operations of the total wells drilled. The addition of Jack and Young Counties to this district accounts for part of this increase, almost 150 wells being completed in the two counties. Production increased slightly over the previous year as a result of an increase in the number of producing wells and a greater demand for this high-gravity, sweet crude oil. The average depth of discovery wells was about 400 ft. deeper than in 1942. Although more discoveries produced from horizons below the base of the Strawn series than from those above the Straw, the deeper horizons, including the Bend series of the Pennsylvanian, the Mississippian limestone and Ellenburger of the Ordo-vician, largely were dissappointing from the viewpoint of major additions to oil reserves. The largest single addition to the reserves was in the basal Strawn sand in the Walnut Bend field, Cooke County. During the year, 31 wells were completed, both in the field and as cxtensions. The most active arca Was Jack County, in which five fields or potential fields were discovered, although only 44 oil wells were completed.

Jan 1, 1944

THE second operation in the art of casting, and one of the greatest importance, is that of melting and thoroughly liquefying the materials of which you wish to make your casting. On this operation depends the whole outcome of your intentions and the perfection of your work. Without it, even though you had a great abundance of moulds and vast quantities of bronze, your desires, labor, and expense would all be in vain. In this operation I find on consideration that, in addition to experience, there are three necessities-perhaps indeed four-that must be provided without fail. The first is the furnace or other agent which contains the fire and the metal brought together. The second is the wood or charcoal which is the necessary and proper nutriment of the fire, from whose virtues are derived the greater or lesser forces which, according to their kind, are ready to effect what is required. The third is to have the materials disposed to easy fusion by means of corruption, alloying, or by their own nature. The fourth, as the motivating cause of the whole, could perhaps be listed as the first-this is the ingenuity and good judgment of the worker, together with the bodily exertions not only of himself but also of his helpers in addition. For, besides a certain ordinary caution, it is necessary to pay particular attention, first, to see that the furnaces, machines, ladles, hearths, refineries, and other kinds of instruments or similar vessels be made so as to dispose the metals for melting, and, when melted, that they easily maintain them so. These should also be prepared in such a way that they cannot be injured by the fire, for if they should be damaged the operation would fail. In order to do this, it is first necessary that you arrange the instruments with forethought and action so that the power of the fire can operate. Fire operates on things only when brought together with them in long-continued operation, or when driven by a great force of wind. It burns many things and softens others, but it makes the metals as liquid as water.

Jan 1, 1942

By R. E. Cech

Particles -3 to 30 µ diam of a 29.5 pet Ni, 70.5 pet Fe alloy after being melted and solidified while falling through a hydrogen atmosphere were found to contain a distortion-free body-centered-cubic phase. In most particles, the amount of body-centered-cubic phase approaches or equals 100 pet. It was shown by a series of experiments that this phase forms directly from the liquid. It is pointed out that a mechanism previously suggested in recent papers on the theory of the liquid-solid transformation can account for the solidification of body-centered-cubic phase in a temperature range where face-centered-cubic is the stable phase. IN the course of an operation to produce powders for a study of the martensitic transformation in Fe-Ni alloys, an unexpected phenomenon was observed. Powders of a 29.5 pet Ni alloy, which has a subzero M, temperature, were found to contain considerable amounts of a body-centered-cubic phase at room temperature. The experiments to be described were designed to elucidate the mode of formation of this unexpected phase. Experiments and Discussion An alloy containing 29.5 wt pet Ni, balance iron, was vacuum melted from high purity electrolytic iron and carbonyl nickel shot and solidified in the crucible. The metal was converted to oxide, ground to 100 pet <37µ, pressed to a cake, and homogenized 20 hr at 1350°C. To insure homogeneity the grinding, pressing, and homogenizing heat treatment was repeated a second time. The oxide was then ground to 100 pct <37µ and hydrogen reduced at 500°C. The reduced powder was given a spheroidizing treatment to produce spherical cast particles. The treatment consisted of dispersing the particles in hydrogen and allowing them to drop through a vertical hydrogen furnace set to a temperature higher than the liquidus of the alloy. This operation, commonly known as shotting, has been described more fully elsewhere.&apos; The powder produced by this method was found to contain approximately equal parts of body-centered-cubic and face-centered-cubic phases. A magnetic separation technique, previously described,&apos; was applied, and it was found that particles were either completely face-centered-cubic or nearly completely body-centered-cubic. The microstruc-

Jan 1, 1957

By James J. Bean

HE task of measuring the specific gravity of the -*- operating medium in a heavy-media separation system has never presented a particularly difficult problem because the medium is fairly stable and the overflow of the separatory vessel, as well as its underflow, can be sampled easily and accurately and the specific gravity of the suspension determined easily by weighing a known volume. However, while this method is simple and accurate it does require the operator to take the sample by hand and to weigh it and there is considerable temptation to avoid the periodic sampling if everything seems to be going well, or if something is occupying the attention of the operator. Furthermore all operators do not sample in exactly the same manner and considerable practice is required for two operators to be able to "check" each other to the last few hundredths, particularly if the sample is cut underneath the drainage screen where location of the point of sampling and load on the screens tends to influence the determination. While none of the above presents much of a problem, we have all recognized that some mechanical method of continuous measurement and recording would be advantageous since the operator would merely have to glance at the meter to check the gravity and to have an indication of the trend of any changes. Also if the instrument were of the recording type, a permanent record would be available for the guidance of the superintendent. The Eagle-Picher Mining and Smelting Co. was the first heavy-media user to actually install such a recording meter. In 1946 they installed in their Central Mill at Cardin, Okla., a specific gravity recorder manufactured by the Bristol Co. of Water-bury, Conn. R. A. Barnes, of the Bristol Co., working with E. H. Crabtree, Jr. and Elmer Isern, of Eagle-Picher, made the application and worked out the problems of sampling and measuring. Their attempts to measure the specific gravity of the medium in the cone itself were not entirely successful and they resorted to an outside sample tube for actually making the determination. Because of the particular flowsheet used, it was possible to tap off from the medium return pipeline a stream of medium and divert it into the sampling tube, which was provided with a constant level overflow and a spigot underflow, and into which the bubbler tubes dipped. The Eagle-Picher installation was successful and its possibilities were recognized by the Mineral Dressing Laboratory of the American Cyanamid Co. It was decided to install a similar unit in the heavy-media pilot plant to investigate further its possibilities. Chief among these was the continuous record which it was felt would be proof of the steadiness of the gravity in a heavy-media cone, something which is not always appreciated by POtential users. Because the heavy-media pilot plant is required to operate at a wide range of specific gravities, it was realized that the unit would have to record all gravities from 1.25 to 3.50, and do it to the nearest 0.01. It would not be necessary to record all of this wide range on a single chart and the method selected was to have 4 bands, each band range overlapping the other a small amount and calibrated so that with standard charts one division would represent 0.01 sp gr. A shift from one band to another could be arranged without alteration of the instrument itself, being accomplished by a simple change in the bubble-tube lengths, as described later. Accordingly, a recording type instrument was purchased and installed. Because there were some advantages in doing so, the first installation attempted to measure the gravity of the cone proper by placing the bubble tubes in the cone. This was not at all satisfactory and the second scheme utilized a fixed vertical screen at the surface of the cone, and an external sample-tube arrangement. We were particularly anxious to make this work as we felt it would be advantageous to measure the top level of medium where the separation was actually being made, but we were doomed to disappointment because it was impossible to keep the screen clean of float. Since the top gravity of the cone is the most convenient place to sample for control, a launder about 2 in. wide was installed longitudinally beneath the

Jan 1, 1951

By James J. Bean

HE task of measuring the specific gravity of the -*- operating medium in a heavy-media separation system has never presented a particularly difficult problem because the medium is fairly stable and the overflow of the separatory vessel, as well as its underflow, can be sampled easily and accurately and the specific gravity of the suspension determined easily by weighing a known volume. However, while this method is simple and accurate it does require the operator to take the sample by hand and to weigh it and there is considerable temptation to avoid the periodic sampling if everything seems to be going well, or if something is occupying the attention of the operator. Furthermore all operators do not sample in exactly the same manner and considerable practice is required for two operators to be able to "check" each other to the last few hundredths, particularly if the sample is cut underneath the drainage screen where location of the point of sampling and load on the screens tends to influence the determination. While none of the above presents much of a problem, we have all recognized that some mechanical method of continuous measurement and recording would be advantageous since the operator would merely have to glance at the meter to check the gravity and to have an indication of the trend of any changes. Also if the instrument were of the recording type, a permanent record would be available for the guidance of the superintendent. The Eagle-Picher Mining and Smelting Co. was the first heavy-media user to actually install such a recording meter. In 1946 they installed in their Central Mill at Cardin, Okla., a specific gravity recorder manufactured by the Bristol Co. of Water-bury, Conn. R. A. Barnes, of the Bristol Co., working with E. H. Crabtree, Jr. and Elmer Isern, of Eagle-Picher, made the application and worked out the problems of sampling and measuring. Their attempts to measure the specific gravity of the medium in the cone itself were not entirely successful and they resorted to an outside sample tube for actually making the determination. Because of the particular flowsheet used, it was possible to tap off from the medium return pipeline a stream of medium and divert it into the sampling tube, which was provided with a constant level overflow and a spigot underflow, and into which the bubbler tubes dipped. The Eagle-Picher installation was successful and its possibilities were recognized by the Mineral Dressing Laboratory of the American Cyanamid Co. It was decided to install a similar unit in the heavy-media pilot plant to investigate further its possibilities. Chief among these was the continuous record which it was felt would be proof of the steadiness of the gravity in a heavy-media cone, something which is not always appreciated by POtential users. Because the heavy-media pilot plant is required to operate at a wide range of specific gravities, it was realized that the unit would have to record all gravities from 1.25 to 3.50, and do it to the nearest 0.01. It would not be necessary to record all of this wide range on a single chart and the method selected was to have 4 bands, each band range overlapping the other a small amount and calibrated so that with standard charts one division would represent 0.01 sp gr. A shift from one band to another could be arranged without alteration of the instrument itself, being accomplished by a simple change in the bubble-tube lengths, as described later. Accordingly, a recording type instrument was purchased and installed. Because there were some advantages in doing so, the first installation attempted to measure the gravity of the cone proper by placing the bubble tubes in the cone. This was not at all satisfactory and the second scheme utilized a fixed vertical screen at the surface of the cone, and an external sample-tube arrangement. We were particularly anxious to make this work as we felt it would be advantageous to measure the top level of medium where the separation was actually being made, but we were doomed to disappointment because it was impossible to keep the screen clean of float. Since the top gravity of the cone is the most convenient place to sample for control, a launder about 2 in. wide was installed longitudinally beneath the

Jan 1, 1951

By Charles Will Wright

THE HIGHLY SPECIALIZED heavy air transport services to mining regions, such as exist in the New Guinea gold fields and in northern Canada, have been even more essential in the development of mines in Peru. Few nations have been con- fronted with greater natural obstacles to transport than has Peru, and without the plane it would have been impossible to get the machinery and supplies for the construction of power plants and mills to many of these interior mines, situated as they are over high mountain ranges, with muleback the principal means of transportation. As the mines within a district become important producers and warrant the expenditure, the mule trail is being replaced by automobile roads to connect with the railway stations and with the airports.

Jan 1, 1940

By AIME AIME

FRANK T. SISCO is a native of Lawrence, Kansas. He received his earlier education in Clinton, Iowa and his university training at the University of Illinois. His experience in the steel industry has included service in the chemical, testing, and metallurgical departments of the Illinois Steel Co., of South Chicago; the Hess Steel Corp., of Baltimore; the IJ. S. Naval Ordnance Plant at Charleston, W. Va.; and the American Steel and Wire Co., Waukegan, Ill. He severed for seven years as chief of the metallurgical laboratories of the U. S. Army Air Corps at Wright Field, Dayton, before coming to New York in 1930 to become metallurgist and editor of the Alloys of Iron Research, the position he now holds.

Jan 1, 1940

By Arthur Crowfoot

As a result of work done, on an operating scale, in its experimental mill during 1920 and 1921, the plan here given was proposed for crushing, grinding, and concentrating low-grade sulfide ores at the Morenci Branch of the Phelps Dodge Corpn. The flow sheet is designed to recover 85 per cent. of the total copper and 95 per cent. of the sulfide copper from ore assaying 2.0 per cent. total copper and 0.3 per cent. acid soluble copper. At present, 1400 tons are treated daily under the conditions of this flow sheet, two 700-ton units having been installed in the 4000-ton concentrator. The run-of-mine ore will be reduced, in the dry-crushing plant, to —6 mesh and then delivered to the concentrator feed bins. The crushing will be done in three stages: (I) Run-of-mine ore is reduced to —2 1/2-in. in a gyratory crusher; (2) the 3-in. ore is reduced to 1/2-in. in 72 by 24 in. rolls; (3) the 1/2-in. ore is reduced to — 6-mesh size in 54 by 24 in. rolls. The 54-in. rolls will operate in closed circuit with electrically vibrated screens, "Hum-mer" type, a conveyor circuit being used to carry the roll product to the screens. Sufficient screens will be installed to pass 1.5 tons undersize per hour per square foot. Fine-ore bin chutes will be piped for compressed air, which will be used intermittently to keep the ore feed in motion if it tends to arch or pipe in the bins. The Concentrator The concentration of the copper and iron sulfides in the ore will be effected in three stages: I. By direct treatment of the —6-mesh crushing-plant product on primary tables, which will recover about 35 per cent. of the original copper content of the ore in a clean granular concentrate. The table middling will be dewatered in Dorr rake classifiers and ground to — 48-mesh in ball mills operating in closed circuit with circulating classifiers.

Jan 1, 1923

By Arthur Crowfoot

As a result of work done, on an operating scale, in its experimental mill during 1920 and 1921, the plan here given was proposed for crushing, grinding, and concentrating low-grade sulfide ores at the Morenci Branch of the Phelps Dodge Corpn. The flow sheet is designed to recover 85 per cent. of the total copper and 95 per cent. of the sulfide copper from ore assaying 2.0 per cent. total copper and 0.3 per cent. acid soluble copper. At present, 1400 tons are treated daily under the conditions of this flow sheet, two 700-ton units having been installed in the 4000-ton concentrator. The run-of-mine ore will be reduced, in the dry-crushing plant, to —6 mesh and then delivered to the concentrator feed bins. The crushing will be done in three stages: (I) Run-of-mine ore is reduced to —2 1/2-in. in a gyratory crusher; (2) the 3-in. ore is reduced to 1/2-in. in 72 by 24 in. rolls; (3) the 1/2-in. ore is reduced to — 6-mesh size in 54 by 24 in. rolls. The 54-in. rolls will operate in closed circuit with electrically vibrated screens, "Hum-mer" type, a conveyor circuit being used to carry the roll product to the screens. Sufficient screens will be installed to pass 1.5 tons undersize per hour per square foot. Fine-ore bin chutes will be piped for compressed air, which will be used intermittently to keep the ore feed in motion if it tends to arch or pipe in the bins. The Concentrator The concentration of the copper and iron sulfides in the ore will be effected in three stages: I. By direct treatment of the —6-mesh crushing-plant product on primary tables, which will recover about 35 per cent. of the original copper content of the ore in a clean granular concentrate. The table middling will be dewatered in Dorr rake classifiers and ground to — 48-mesh in ball mills operating in closed circuit with circulating classifiers.

Jan 1, 1923

By Luis Emylnn Salas

If the ordinary wet method be attempted for silver-bullion containing tin, much trouble is experienced, varying with the amount of tin present. Even with a percentage as low as 0.05, the end-point is masked by a persistent turbidity, while with amounts ranging from 0.5 per cent. upward, the determination of the exact end-point is impossible, owing to the finely divided or colloidal metastannic acid resisting all efforts to cause it to settle, or to give a clear supernatant liquid. The object of the following experiments was to seek a remedy for these difficulties, and to find the conditions whereby the Gay Lussac method might be applied directly to these bullions. Material containing tin is met with frequently in bullion from Mexico or Bolivia; and tin is carried (sometimes in large quantities) in jewelers&apos; sweeps. 1. A bullion was prepared containing Ag, 74; Cu, 25; and Sn, 1 per cent. A weighed amount was treated by the humid assay-method as if it were an ordinary bullion free from tin. Ten cc. of HNO, (1.21) was added, and the bottle was heated until all traces of

Jan 1, 1913

By Enrique Touceda, Henry M. Howe

This paper gives the composition of the iron and slag at different stages in the " air-furnace" process of preparing " hard metal," or white castriron, for conversion into malleable cast-iron by annealing. The details of the process are given in an appendix. One of us had been trying for years to work some chemist of some of our malleable-iron plants up to a degree of enthusiasm which would lead him to make such an investigation. It would have had the advantage of the greater familiarity with the conditions which one habitually on the spot must have. Failing in this, he made use of an opportunity which presented itself of taking samples here represented, with such fairness as the conditions permitted, holding firmly that a rough approximation to the truth is better than the complete lack of data, or that a bird in the hand is worth two in the bush. We hope that this attempt may stimulate others effectively to duplicate this work, and thus correct or confirm it. Our results are shown in Table I. and graphically in Figs. 1 arid 2. Discussion.—At the time when the first two samples were taken, the metal and slag were still too sluggish to permit fair sampling, and not until sample 6 were the conditions really favorable, because at the time of the fourth sample the metal was not fully melted, and even at the time of sample 5 it was still sluggish. Indeed, the slag was probably very heterogeneous throughout, because it took up silica and alumina rapidly from the bottom, and because it was so siliceous as to be sluggish at this relatively low temperature. This hetero-geneousness is exaggerated in the two samples of slag 8, apparently by the great viscosity due to its extraordinary acidity. Note that the manganous oxide of one sample is about two and

Jan 1, 1909

By G. G. Priest, B. E. Morgan

The production of oil and gas from wells is often seriously hindered by the compaction of solids in the perforations during the perforating process. To realize the full productive capacity of a well, it is necessary either to remove the plugging material from the perforations or to perforate in a manner which does not cause plugging of the perforations. The latter method can be accomplished by having a non-plugging fluid in the casing at the time the well is perforated. This paper describes the results of laboratory tests, perforating tests, and experimental field tests which demonstrate that certain emulsions serve effectively as non-plugging perforating fluids. The principal components of these emulsions are two liquids: an aqueous phase consisting of a solution of either sodium chloride or calcium chloride, and an oil phase consisting of diesel oil, tetrachloroethylene, or a combination of both. Small amounts of other agents which serve to stubilize the emulsions, to reduce the fluid loss, and to inhibit corrosion are also present. The density of the emulsions is controllable within the range of 7.5 to 12.5 lb/gal; no insoluble solids are present, the filtration rate is low, and the thermal stability is satisfactory at temperatures as high as 200°F. The corrosion of steel by these emulsions is negligible. Tests conducted under conditions which simulate the temperature and the pressure in an actual well demonstrate that these emulsions fulfill the requirements of a non-plugging perforating fluid. In addition, lirnited field experience furnishes evidence that these emulsions remain in position after they are spotted, that they are retained in the casing after the perforations are made, and that they are easily removed from the perforations when the well is opened for production. When the pressure in the borehole is greater than the formation pressure at the time a well is perforated, plugging of the perforations can be avoided by spotting an emulsion adjacent the interval to be perforated. This procedure should eliminate low well productivity caused by plugging the perforations. INTRODUCTION Nature of Problem The most widely used method for the completion of oil and gas wells is to set and cement casing through productive horizons, and then to obtain production by gun-perforating the section of casing opposite the desired interval. This method is gen- erally successful and it was thought at one time that those failures which did occur were due to insufficient penetration by the perforator. Despite recent improvements in perforators which assure ample penetration, unsatisfactory fluid production continues to be a problem. Evidently, the trouble comes from some other source. Recent results obtained by Allen and Worzel1 demonstrated that low fluid productivity may be caused by the perforating process and/or by the fluid in the wellbore at the time of shooting. They found that perforations are often completely plugged by debris from the perforator, pulverized sand from the formation, and compacted solids from the drilling mud when the pressure in the wellbore is greater than the pressure in the formation at the time of perforation. In some cases a differential pressure in excess of 400 psi was required to initiate flow into the well through these plugged perforations. The plugging of perforations by solids not only causes low productivity from wells, but it creates simultaneously other problems in the production of oil and gas. For example, when most of the perforations are plugged, high rates of flow must occur through the few perforations that are open. The resulting high pressure drop may cause production

Jan 1, 1958