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By D. Walton

The effect of small solute additions of Cu on the activation energies for creep A1 single crystals were determined over the range from 78° to 850° K. Below 240°K and above 800°K activation energies were unchanged. Between 240°K and 400°K strain aging causes the creep rate to become vanishingly small and the flow stress was independent of the temperature. Between 500° and 50°K the activation energy was increased to 41,000 cal per mole. NUMEROUS investigationsL have shown that solid solution alloying invariably increases the flow stress. A typical example is documented in Fig. 1. Such increases in flow stress can arise from two general effects: Alloying can increase the long-range stress fields through which dislocations must move by causing appropriate clustering; modification of dislocation densities, and so forth. Alloying can also modify the short-range stress fields that determine the activation energies for thermally stimulated migration of dislocations, such as occurs in some solute atom pinning processes, and so forth. Actually both long- and short-range stress-field effects can occur simultaneously. It was the purpose of this investigation to evaluate the effect of alloying on the short-range stress fields by determining the effect of alloying on the activation energies for creep. The resulting observations also shed some light on the effect of long-range stress fields on dislocation processes. EXPERIMENTAL TECHNIQUE Single-crystal bars (6 in. long 3/8 in. wide and l/4 in. thick) of dilute solutions of Cu in A1 were seeded, so as to provide extensive single slip, with the pole of the tensile axis located in the standard stereographic projection as shown in Fig. 2. Each crystal was grown under an argon atmosphere in a graphite mold containing a large reservoir of molten alloy for the purpose of obtaining rather uniform composition of Cu along the length of the bar. The nominal compositions of the alloys which were produced from 99.99 pct Cu and high-purity A1 containing 0.001 pct Fe and 0.001 pct Si, are given in Table I. Strains, measured by linear variable transformers attached by quartz rods to a 3 in. gage section were sensitive to and the stresses were ap- plied by direct loading of the specimen. Temperatures were determined by thermocouples attached to the gage section of the specimens. Below 400°K the apparent activation energies for creep, Q, were determined by the effect of small, rapid changes in temperature of about + 10°K from T1 to T2 on the corresponding creep rates ?1 and ?2 during primary creep according to where R is the gas constant.' Above 400°K, Q was evaluated from Eq. [1] for the secondary creep rate using temperature changes of about ±20K. A typical set of results is shown in Fig. 3. RESULTS AND DISCUSSION The previously obtained effect of temperature on the apparent activation energy for creep of single crystals of high-purity A12 is shown by the broken curve of Fig. 4. The datum points on the same graph illustrate the effect of dilute a solid solution alloying with Cu on the activation energy between 600" and 750°K. Each plotted point is the average of not less than five independent test values between 600° and 750°K and not less than three at other tempera-

Jan 1, 1962

By T. A. Rickard

A knowledge of the principles of punctuation is essential to effective and intelligible writing, for the ease and pleasure of the reader, and even his understanding, may depend upon the choice and the placing of punctuation marks. To 'punctuate' is to mark with stops or points; the word comes from the medieval Latin punctuare (punctuatus), which in turn is derived from the Latin punctum, a point. The purpose of punctuation is to show the manner in which the writing is to be understood; to indicate the relations between parts of a sentence and between successive sentences. To some extent "it does for the eye what vocal stress does for the ear", but especially it marks logical relations. Some punctuation marks, such as those indicating admiration, exclamation, and interrogation, are rhetorical as well as grammatical, but most of the common ones are logical, or grammatical. My discussion will be confined to grammatical punctuation in ordinary writing. .'The problem of punctuation in text matter", as George Summey * says, "is to employ words, points, and paragraph breaks in such a way as to achieve at the same time clearness; proper distribution of emphasis, and the desired kind of movement." The criticism of the punctuation of a sentence or of a group of sentences is not final until the context, within the paragraph, is read. A paragraph is a sentence or a group of sentences forming an independent unit of the composition; it represents a unit of thought. A multiplicity of paragraphs produces a choppy effect; 'on the other hand, paragraphs of. excessive length are tiresome, because the belaboring of one unit of thought wearies the reader. The aim should be to

Jan 1, 1931

By F. S. McNicholas

IN the writer's opinion the term "block caving" has been rather loosely applied to a general principle of mining, and therefore detailed classification of caving methods and draw, together with the characteristics required for each method, will fill a desired need. Selection of caving method should be made only after a study of all governing conditions, such as size of orebody, lateral and vertical extent of ore-body, attitude, treatment demands, possible resultant pressures, and cost and profit comparison of methods. Successful caving methods can be classified under six main headings: (1) Full-protected block caving, (2) semi-protected block caving, (3) unprotected block caving, (4) full-panel caving, (5) half block-panel caving, (6) block-panel caving. The methods and factors governing choice of method are shown in Table I. Full-protected Block Caving Full-protected block caving consists of develop-ing, undercutting, and drawing to exhaustion a block of ore of predetermined size without coordination of mining or draw with adjoining areas. The block is mined and drawn as an independent unit (Fig. 1). Full-protected block caving demands that mining and draw cannot be done against unconsolidated capping in adjoining caved and exhausted blocks. Two sides of block are against solid. Caved capping must be allowed to consolidate for a suitable period, usually not less than one year. Pillars may be left in lieu of consolidated capping (Fig. 2). The advantages of full-protected block, caving are: (1) A definite area is developed, mined, and drawn as a unit so that all work may be completed, the block drawn to exhaustion in the minimum length of time, and the area then abandoned. (? Production is not restrained because of coordina1, on with adjoining areas. (3) Records of draw and caved reserve of ore are good. Upon abanwnment of the block, accountability for production is closed out with no carry-over to adjoining areas. The disadvantages of full-protected block caving are: (1) Side dilution from the draw adjacent to the consolidated capping may be serious, particularly where capping does not consolidate sufficiently in the allotted time. (2) Boundary weakening is needed on the solid sides of the block except in weak rocks. (3) Maximum cantilever and compression effect to aid caving and fragmentation may not be secured since the draw should proceed from the solid to the consolidated capping to minimize side dilution. However, undercutting from the loose (caved capping) to the solid with a slight initial draw in the same manner will develop cantilever effect. (4) A period of at least one year, more is usually desirable, must be allowed for caved capping ,to consolidate before mining the adjoining block, depending upon the characteristics of the capping. (5) Capping may not consolidate sufficiently in the time that can be allowed. Full-protected block caving is indicated where: (1) The ground is weak and heavy and workings

Jan 1, 1952

By M. A. Westbrook, J. F. Redmond

A method is presented for obtaining porosities of consolidated formations from the drill returns. The method provides a means of determining the bulk volume of a large number of particles, such as drill cuttings, by employing a capillary diaphragm for removal of surplus surface liquid from saturated cuttings having pores of capillary size, which reduces tile amount of error present in former attempts to determine the porosity of drill cuttings. The method makes it possible to obtain a considerable amount of supplementary data on consolidated formations. Introduction Porosity is a direct measure Of the volume of the voids in a formation. It may be used for estimating the permeability of a formation provided that a correlation of these two properties has been obtained from the analysis of cores from the particular formation, and it forms a desirable aid in interpreting electric logs.1 These useful applications have emphasized the importance of developing a method for determining the porosity of the formations penetrated by a well by some means other than coring, for even in exploration wells it is neither economical nor practical to core all formations. Also, in wells where at the outset the coring program appears comprehensive, it is frequently found that, after certain layers are drilled. more complete information is required for evaluation. Porosity values, if obtainable, would be of great assistance in such cases. In soft formations it is usually possible to obtain porosities after drilling with cores taken by side-wall coring devices. In hard consolidated formations, that coring procedure is not alway practicable and other methods for determining porosities must be resorted to. A first choice is the examination of drill cuttings. if an analytical procedure is available that is both accurate and reasonably rapid. Such a procedure has been devised and is applicable to sand and limestone cuttings having pores of capillary size. Although imp,ovements can yet be made, it is believed that the new technique is sufficiently well developed to warrant description, Preparation of Sample The well samples containing the cuttings representative of the particular intervals are first washed through a No' 6 gauge screen. The cuttings remaining on the Screen are large enough to use lor the porosity measurements' From the sized sample, the cuttings to be examined are separated from the shale and Other extraneous particles. It is recommended that 10 to 15 c.c. of the selected cuttings be used for measurements, although only 4 to 5 c c. were used to make the comparative tests described later in this article. These cuttings are extracted and dried by the same methods used for preparing core samples for porosity and other measurements. The separation, which is at present being carried out by hand, is the most tedious

Jan 1, 1946

By M. A. Westbrook, J. F. Redmond

A method is presented for obtaining porosities of consolidated formations from the drill returns. The method provides a means of determining the bulk volume of a large number of particles, such as drill cuttings, by employing a capillary diaphragm for removal of surplus surface liquid from saturated cuttings having pores of capillary size, which reduces tile amount of error present in former attempts to determine the porosity of drill cuttings. The method makes it possible to obtain a considerable amount of supplementary data on consolidated formations. Introduction Porosity is a direct measure Of the volume of the voids in a formation. It may be used for estimating the permeability of a formation provided that a correlation of these two properties has been obtained from the analysis of cores from the particular formation, and it forms a desirable aid in interpreting electric logs.1 These useful applications have emphasized the importance of developing a method for determining the porosity of the formations penetrated by a well by some means other than coring, for even in exploration wells it is neither economical nor practical to core all formations. Also, in wells where at the outset the coring program appears comprehensive, it is frequently found that, after certain layers are drilled. more complete information is required for evaluation. Porosity values, if obtainable, would be of great assistance in such cases. In soft formations it is usually possible to obtain porosities after drilling with cores taken by side-wall coring devices. In hard consolidated formations, that coring procedure is not alway practicable and other methods for determining porosities must be resorted to. A first choice is the examination of drill cuttings. if an analytical procedure is available that is both accurate and reasonably rapid. Such a procedure has been devised and is applicable to sand and limestone cuttings having pores of capillary size. Although imp,ovements can yet be made, it is believed that the new technique is sufficiently well developed to warrant description, Preparation of Sample The well samples containing the cuttings representative of the particular intervals are first washed through a No' 6 gauge screen. The cuttings remaining on the Screen are large enough to use lor the porosity measurements' From the sized sample, the cuttings to be examined are separated from the shale and Other extraneous particles. It is recommended that 10 to 15 c.c. of the selected cuttings be used for measurements, although only 4 to 5 c c. were used to make the comparative tests described later in this article. These cuttings are extracted and dried by the same methods used for preparing core samples for porosity and other measurements. The separation, which is at present being carried out by hand, is the most tedious

Jan 1, 1946

Extractive Metallurgy Division Institute of Metals Division Iron and Steel Division OFFICERS AND COMMITTEES W R Hibbard, Jr , President J C Kinnear, Jr , Past President John Chipman, Vice-President T D Jones, Treasurer R W Shearman, Secretary AIME, 29 West 39th Street New York 18, N Y

Jan 1, 1958

By D. Jenkins

THE Franklin Laboratory was designed mainly for the analysis of the products from the two concentrating mills situated at Franklin and Sterling Hill, the most important determinations being the zinc, iron, manganese, lime, moisture and silica contents of the ores. Within the last 4 years, however, it has been found advisable to examine most of our supplies, and therefore additional space and equipment was allotted for the examination of such substances as oils, greases, soaps, alloys, fuels, paints, explosives and water. The building as shown in elevation (Fig. 1) and plan (Fig. 2) consists of a main or routine laboratory, an experimental laboratory, a water FIG. 1.-WEST ELEVATION. analysis room and the other accessories such as stock room, library, sampling and drying rooms and office. The main laboratory is further divided into a balance room and zinc analysis room. As the greater part of our determinations are volumetric, good light is a very important factor and with this in view the interior walls of the building were constructed of white enameled brick laid in Keene cement. These also have the additional advantage that they give a clean and attractive appearance to the room. The windows are large, being 76 by 44 in. and even on very dark days the light is good throughout the whole laboratory. Our zinc titration requires a constant light and as, on many days, especially in winter, the light is variable, we installed two Artificial

Jan 8, 1917

By Chester Washburne

LEASING the Teapot dome to the Mammoth Oil Co. is the culminating anticlimax of the "conserva-tion movement." It is just the touch required to make a full fiasco of the whole affair. If the revered wielder of the "Big Stick" were still with us, we could hear it fall harder than it did on Ballinger. Of all the oil reserves set aside by presidential decree, there was only one which certainly could con-serve much oil for the future. This was Naval Reserve No. 3, on the Teapot dome, Wyoming. After secret negotiations, carefully guarded from the press and from the knowledge of other oil men, we are suddenly informed that this last and only known chance to save much oil for future naval needs has been given away for early development.

Jan 6, 1922

By T. Y. Yan, W. F. Espewheid

The various ion exchange reactions occurring during restoration of formations contaminated with ammonia during in situ uranium leaching are reviewed. Data are presented on the restoration of a previously leached laboratory packed column wing lime saturated brine. Although this restoration fluid selectively and effectively removed the ammonia, 24.5 pore volumes are required to reduce the ammonia concentration from 500-3 mg/L (29- 0.18 gr per gal). The essence of NaCl in the restoration fluid at levels in formation water is beneficial in improving the selectivity of the system for NH4+ removal and reducing Ca + + ion consumption

Jan 1, 1984

By R. J. De Angelis, J. B. Cohen, A. Nelson

In this note several recent results on twinning in copper shock-loaded with planar shock waves will be presented and the role of the twins in recrystalliza-tion will be discussed. The twinlike markings first observed in shock-loaded copper by smith1 were identified as twins by De Angelis and Cohen.2 This identification has been confirmed by others.3 In Ref. 2 it was also shown that there is an orientation dependence for twinning at low shock pressures, such that twins in a crystal loaded in [lll] form in the rarefaction or tensile wave but in

Jan 1, 1967

By A. L. Holley

IN order to put sufficient work on steel ingots for rails, they must be reduced from about 12 inches square. As this cannot be done at one heat, they are first drawn down to about 7 inches square, and then reheated and rolled into rails. This first reduction or " blooming," is usually done in this country in a 30-inch 3-high rolling-mill, with movable rolls, so as to get several reductions in each set of grooves. The first of these mills has been running at the Troy Steel-works above a year, with great success. Another at the Cambria Iron-

Jan 1, 1873

By Ben Gumpertz

The important factors in any study of the screening of sand with a gravel envelope, as applied to use in oil wells, are: (I) sand size and shape, (z) gravel size and shape, (3) ratio of gravel size to sand size, (4) flow velocity, (5) viscosity of the fluid. Perhaps the first extensive investigation of the function of gravel in screening sand was performed by Coberly and Wagner,' from which the following conclusion was drawn: "The diameter of the largest grains in a single classified sand suitable for gravel packing is approximately 13 times the grain size at the ten-percentile analysis of the formation sample." ?;his applies to sands classified by Tyler screens and is for gravel grains of the maximum size that could be used to form a stable bridge. Field practice has shown that the screening effect of a given gravel for a given sand apparently varies with the flow velocity." Also, it has been assumed by some operators that the thickness of the walls of the gravel envelope surrounding the well has little effect upon the screening process. It is thought by others that a narrow envelope of gravel might form an ineffective screen. Thus the purposes of this work are: 1. To investigate the effect of gravel-sand size ratio upon screening action under the condition of varying flow velocities. 2. To investigate the effect upon screening action of varying the thickness of the gravel screen. 3. To investigate sand migration in the gravel screen and the effect of flow velocity and gravel size upon sand migration. Description of Apparatus In an attempt to reproduce field conditions for the purposes of this investigation, a flow tube was constructed, according to the manner of Urenj3 to represent a radial drainage segment of an oil sand. To arrive at the dimensions of the flow tube, a radial drainage segment of rectangular cross section was assumed to define an area of z sq. in. on the face of a well 6 in. in diameter. From this the dimensions of the segment were calculated out to a distance of 5 ft. from the face of the well. By computing cross-sectional areas at a number of sections along the rectangular segment and transforming these areas into the circular form, a drainage cone was obtained having everywhere the same cross-sectional area as the drainage element of rectangular cross section. To construct the apparatus, two sections of pipe of 7%-in. inside diameter, one 13 in. and the other 4 ft. long, were joined by a bolted flange. A mandrel having the dimensions of the drainage cone was centered in the pipe and a neat cement mixture was cast around it. A protective gasket was placed between the two sections of pipe so that the cement body could be separated at that point. When the mandrel was withdrawn a drainage cone was obtained (Fig. I).

Jan 1, 1941

By Ben Gumpertz

The important factors in any study of the screening of sand with a gravel envelope, as applied to use in oil wells, are: (I) sand size and shape, (z) gravel size and shape, (3) ratio of gravel size to sand size, (4) flow velocity, (5) viscosity of the fluid. Perhaps the first extensive investigation of the function of gravel in screening sand was performed by Coberly and Wagner,' from which the following conclusion was drawn: "The diameter of the largest grains in a single classified sand suitable for gravel packing is approximately 13 times the grain size at the ten-percentile analysis of the formation sample." ?;his applies to sands classified by Tyler screens and is for gravel grains of the maximum size that could be used to form a stable bridge. Field practice has shown that the screening effect of a given gravel for a given sand apparently varies with the flow velocity." Also, it has been assumed by some operators that the thickness of the walls of the gravel envelope surrounding the well has little effect upon the screening process. It is thought by others that a narrow envelope of gravel might form an ineffective screen. Thus the purposes of this work are: 1. To investigate the effect of gravel-sand size ratio upon screening action under the condition of varying flow velocities. 2. To investigate the effect upon screening action of varying the thickness of the gravel screen. 3. To investigate sand migration in the gravel screen and the effect of flow velocity and gravel size upon sand migration. Description of Apparatus In an attempt to reproduce field conditions for the purposes of this investigation, a flow tube was constructed, according to the manner of Urenj3 to represent a radial drainage segment of an oil sand. To arrive at the dimensions of the flow tube, a radial drainage segment of rectangular cross section was assumed to define an area of z sq. in. on the face of a well 6 in. in diameter. From this the dimensions of the segment were calculated out to a distance of 5 ft. from the face of the well. By computing cross-sectional areas at a number of sections along the rectangular segment and transforming these areas into the circular form, a drainage cone was obtained having everywhere the same cross-sectional area as the drainage element of rectangular cross section. To construct the apparatus, two sections of pipe of 7%-in. inside diameter, one 13 in. and the other 4 ft. long, were joined by a bolted flange. A mandrel having the dimensions of the drainage cone was centered in the pipe and a neat cement mixture was cast around it. A protective gasket was placed between the two sections of pipe so that the cement body could be separated at that point. When the mandrel was withdrawn a drainage cone was obtained (Fig. I).

Jan 1, 1941

By A. B. T. Werner, J. J. Schanz

A survey of the world's sources and markets for natural graphite and some predictions of future trends are presented here. The authors feel that there is no indication of major changes in sources of graphite over the next few years, but it is possible that the importance of domestic graphites as opposed to foreign carbons may increase in the more distant future. U.S. consumption of natural graphite, which has been in general decline for the past six years, and will probably continue downhill with the virtual disappearance of some markets. However, other markets such as bearings, brake linings and crucibles will probably grow. Natural graphite is the name given to all the naturally occurring mineral forms of carbon that crystallize in the hexagonal system. Natural graphite~ are generally divided into three broad classifications that are based on physical rather than chemical differences — crystalline flake, Ceylon amorphous and other amorphous. Crystalline flake graphites occur as thousands of small individual flakes disseminated throughout the ore and closely resemble shiny black fish scales. Ceylon amorphous graphite is mined from narrow veins of almost pure mineral. It is produced in lump form and often has a coarse platy or needlelike structure. Other amorphous graphites include all those that are extremely fine-grained and have a crystalline structure that is not visible under normal circumstances. In the primary raw material markets, the graphite's country of origin is also important. Crystalline flake graphites may, for example, be of the Alabaman, Bavarian or Madagascan types; Ceylon amorphous graphite may have originated in Montana or Ceylon; and other amorphous graphites may come from Mexico, Hong Kong or Korea. The distinctions between the graphites from each particular locality are small yet important, for the country of origin will signify certain inherent physical characteristics and will often give an idea of the amount of graphitic carbon contained in the shipment in question. .In certain instances, however, even this is not enough, since the actual mine at which the graphite is produced may have to be known before its true commercial value can be ascertained. Thus, the Madagascar flake graphite shipped from the Sahalambo mines of the Societe des Graphites de la Sahanavo is a thick flake which is known to be especially suited for use in crucibles, while the dull black earthy amorphous material formerly mined at Cranston, R.I., was ideal for stove polish. Synthetic, artificial, electric furnace and manufactured are terms used to describe graphites made from coke. These graphites will be considered in this paper only to the extent that they enter competition with natural graphite. DOMESTIC SOURCES OF NATURAL GRAPHITES Natural graphites have been produced from mines in Alabama, Alaska, California, Georgia, Montana, New Jersey, New York, North Carolina, Pennsylvania, Rhode Island, Texas and other states. The exception is the crystalline minerals resembling Ceylon graphite that have come from Montana and the amorphous meta-anthracites from Rhode Island. All the products mined have been flake graphite. In 1960, production was reported only in Texas and Pennsylvania. The Alabama graphite deposits of flake in quartz-mica schists are found southeast of Birmingham in a narrow belt that extends for about 60 miles southwest from Delta in Randolph County to Verbena in Chilton County. Since the long-run prospects for Alabama graphites appear to be fairly bright, especially if regular production of high quality output becomes possible, regional ore reserves of all kinds, including indicated and inferred, are estimated to be of the order of 25 million tons. Of this amount, 14 million tons are of the weathered variety. Alabama graphites are favored by their relative ease of mining, and by the fact that special methods of milling have been developed at the larger properties. In addition, the steady rise in ocean freight rates for Madagascar graphites, the tendency among crucible manufacturers to use flakes of a smaller size, and the possibility of producing other salable byproducts in addition to the graphite are favorable to Alabama producers. Against

Jan 1, 1962

By Gary E. McIntosh

This paper will discuss a US Bureau of Mines project designed to assess and predict the impacts which surface coal mining will have on the regional shallow groundwater system in the Powder River Basin. The primary objective will be met through the accomplishment of the following: (1) The design and establishment of a regional network for monitoring shallow groundwater systems in the basin; (2) monitoring the direction and rate of flow, water quality, and aquifer characteristics of the shallow groundwater systems; and (3) development of a regional groundwater simulation model, with appurtenant subroutines to determine local effects.

Jan 4, 1979

By Olaf N. Rove

YEAR 1951 has been bright for the mining geologist. He has arrived after struggling for a generation or two to sell his wares through service to the operator, the mine superintendent, and the manager. But as he establishes himself on the operating front, he is faced with even greater challenges; namely, the development of basic geologic principles governing ore-forming processes and the occurrence and distribution of mineral deposits. These principles are needed to guide his ever-widening search into new areas. He must now stimulate the interest, confidence, and imagination of the mining executive and layman in fostering the research essential to expand rapidly the basic science of geology and its more specific applications to the mining industry. The hallowed time-tested tools of the prospector and the industry are no longer adequate. New basic data, principles, and ideas are needed to guide industry's exploration. The entry of Government into exploration, by lending money to prospectors and operating companies to partly finance exploration, is one of the major events of the year. This was one of the activities for which the Defense Minerals Administration was established in the Department of the Interior. DMA was staffed largely with men from industry, but the Bureau of Mines and the Geological Survey have acted as its technical advisors and have provided its field staff. Since the start of this work in May 1951 to November 19, 1951, the DMA has approved 208 exploration projects while denying 318 others. The contracts involve about eleven million dollars worth of exploration, of which Government's share is about sixty percent. A few contractors have already made discoveries and are into production to repay their loans; others have completed their projects without making a discovery. In November, the DMA was split into two successor units. The Defense Minerals Exploration Administration was set up in the Interior Department to carry out the exploration program. The Defense Materials Procurement Agency was organized as a separate agency to carry out the other functions of the former DMA, as well as general strategic materials procurement. The strategic materials group of the Economic Cooperation Administration was transferred to DMPA in order to centralize the procurement from foreign sources into one agency, although the authority and scope of activities of this group have not been announced as of the middle of December. The DMA-DMEA-DMPA programs are making large demands upon the technical manpower of the Geological Survey and Bureau of Mines. It is still too early to evaluate with confidence the productiveness of this diversion so far as the immediate and long-range effects are concerned. Many of the individuals associated with these programs, as well as others in the industry, are convinced that from a long-range national viewpoint, the regular programs of both the Survey and the Bureau equal or even exceed in importance the current emergency mineral activities of these two agencies. Uranium Uranium continued to be the glamour-girl metal of the mineral industry, and at the request of the Atomic Energy Commission uranium and thorium were included in the DMA exploration program. Industry's intensive prospecting and mining activities in 1950 were further expanded early in 1951 when the Atomic Energy Commission announced an increased price schedule and a new bonus payment

Jan 1, 1952

By Alexander L. Holley

IN order to put sufficient work on steel ingots for rails, they must be reduced from about 12 inches square. As this cannot be done at one heat, they are first drawn down to about 7 inches square, and then reheated and rolled into rails. This first reduction or " blooming," is usually done in this country in a 30-inch 3-high rolling-mill, with movable rolls, so as to get several reductions in each set of grooves. The first of these mills has been running at the Troy Steel-works above a year, with great success. Another at the Cambria Iron

By H. W. Mead, C. E. Birchenall

SELF-DIFFUSION of cobalt has been investigated by Ruder and Birchenall,1, 2 Nix and Jaumot,3 and Gruzin.4 The results for a given tem- perature differ by a factor of about six in the extreme cases with no really close agreement between any two sets of data. The first two groups of investigators employed the decrease of surface activity method. Since Ruder and Birchenall have shown that the values obtained from this method are sensitive to the surface preparation, it seemed desirable to perform a few check experiments by a method not open to this objection.

Jan 1, 1956

By C. S. Corbett

There is much comment at present in the ranks of the oil industry regarding unit operation of oil fields and the benefit that would accrue if it could be extensively applied. It seems certain that, as an immediate corrective of the present situation, overproduction could be effectively curtailed with all the advantages of proper conservation of petroleum resources and with no important loss to anyone connected with the industry. Unit Operation in Certain Foreign Fields Many an oil operator in America would doubtless like to have exclusive control of one or more oil-bearing structures for development in accordance with the economic position of the industry and especially in accordance with the best production practice known. A few operators now have this privilege, particularly in certain foreign fields, and are following lines of procedure which show that they are aware of the great opportunity that is theirs. We find in an article by Professor Strigeoff,1 and in a paper read by Captain Comins2 before the American Petroleum Institute, the outlines of procedure adopted, respectively, by the Soviet Government for the nationalized Russian oil fields and by the Anglo-Persian Oil Co. for its fields in Persia. Comprehensive plans for the unit operation of other oil fields may have been described publicly but no such descriptions have come to the attention of the writer. New fields are coming more and more into the hands of single operators or of a few who control large activities and who appreciate fully the need for cooperative action and are willing to forego the lure of a large quick profit from high flush production in order to secure the advantage of better stabilization in the industry and a larger though more deferred profit by operating the field as a unit. Much can be done toward efficient development of an oil field controlled by a few operators who are willing to cooperate for that purpose, but the best result can be obtained only by pooling their interests in the field

Jan 1, 1930

By David Segura

THE Huitzuco mercury deposits have been described by C. W. Vaupell,1 therefore the general information such as location, history, production, etc. will not be repeated here. The present owners acquired the property when the deep levels of the Cruz mine were flooded, and it was believed that a relatively large tonnage of low-grade ore and fills would be encountered in the flooded section, because of the early mining methods used in the Cruz mine. The mine was partly unwatered and about 187,000 tons of fills was pit-sampled in the San Cayetano stope. These fills average 2.4 kg. Hg per ton. During the period of maximum production at Huitzuco, the ores were sorted in the mine and cobbed into 3-in. pieces, which were treated in Scott furnaces. Large pieces of raw ore are found in the sinter, and it is indicated that both recovery and costs were not very satisfactory. Recent practice has been to treat the ores in closed retorts made of 10-in. pipes. Because of the presence of combined antimony in the mineral livingstonite (HgS.2Sb2S3) and considerable native sulphur, little or no metallic mercury is recovered in the condensers and a second retorting of the condenser muds is necessary. This makes the treatment of the ores expensive and tends to low recoveries of mercury. The principal costs of retorting are, in their relative order: (1) fuel, (2) low recovery of mercury, (3) replacement of retort pipes, (4) labor. METHODS TESTED Three series of experiments have been made, with the object of reducing the costs of recovering mercury and antimony from the ores, by: (1) wet metallurgical methods, (2) bulk roasting in large mechanical furnaces, (3) concentration to reduce the bulk to be followed by roasting in some mechanical furnace. The wet metallurgical methods did not appear feasible because of the high cost of the alkaline solvents used, and investigations of these were not carried beyond the preliminary stage.

Jan 1, 1938