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By J. R. McWilliams

THE task of recovering most of the contents of an oil and gas reservoir economically presents many and varied problems. In order to attempt intelligently a solution to these problems, an understanding of fundamental physical laws is essential. As the pertinent facts needed in applying these laws to recovery problems are not readily obtainable, observation must be made and the data tabulated. Here, good judgment must be exercised, for at best the information is meager. The engineer is well fitted to undertake the task of solving this problem. In my opinion, the decision on the part of some production executives to allow the engineer to cope with the oil recovery situation and other problems, is an outstanding example of improvement in production methods. The executive head must make this decision or the qualified engineer will be working under a severe handicap with the present system of supervising the production of oil and gas. A qualified engineer should have not only the required technical training but also enough field experience to enable him to understand the difficulties encountered in producing oil and gas. Such a man tactfully cooperating with the practical oil man can greatly improve present methods of oil recovery. The realization that nature's forces have not been efficiently controlled in past recovery of petroleum deposits has recently brought distinct improvement in production methods. Papers are to be presented at this meeting discussing in detail improved methods of conserving gas in both flowing and pumping wells, and also methods of lifting oil after Nature's supply of gas has proved inadequate. The application of back pressure to producing oil wells has not, to my knowledge, been extensively applied in Oklahoma or Kansas up to the present time. Most of the flowing wells are allowed to flow through the casing until the rock pressure has been dissipated. However, some flowing wells have been tubed before the well stopped flowing through the casing. Recording pressure-gages can be installed to study well performance.

Jan 11, 1926

There have been no major field developments during 1935. Operations have proceeded normally on the company's three producing fields, Masjid-i-Sulaiman, Haft Kel and Naft-i-Shah. The refinery at Kermanshah was commissioned in September, 1935, with a rated throughput capacity of 75,000 tons a year of topped crude to meet local requirements. Crude production from the Masjid-i-Sulaiman and Haft Kel fields is tabulated below: Masjid-i-Sulaiman Field.—The flowing lives of wells have been extended by (I) a process of acid treatment, thereby reducing the bottom-hole pressure differentials, and (2) by reducing the back-pressure. Optimum producing conditions for individual wells have been determined as a result of an experimental study of the amount of available energy in the reservoir crude and of energy losses in flowing wells. The return of surplus products to the reservoir has continued to be a satisfactory economic operation and the crude throughput capacity of the topping plant has been increased. The viscosity of residue returned to the reservoir is reduced before injection by regassing at 35 lb. per sq. in. absorption pressure with surplus gas. The pressure in the gas dome is falling at the low rate of one pound per annum. Haft Kel Field.—The delimitation of the main structure has proceeded; the oil-bearing area so far proved being about 50 square miles.

Jan 1, 1936

There have been no major field developments during 1935. Operations have proceeded normally on the company's three producing fields, Masjid-i-Sulaiman, Haft Kel and Naft-i-Shah. The refinery at Kermanshah was commissioned in September, 1935, with a rated throughput capacity of 75,000 tons a year of topped crude to meet local requirements. Crude production from the Masjid-i-Sulaiman and Haft Kel fields is tabulated below: Masjid-i-Sulaiman Field.—The flowing lives of wells have been extended by (I) a process of acid treatment, thereby reducing the bottom-hole pressure differentials, and (2) by reducing the back-pressure. Optimum producing conditions for individual wells have been determined as a result of an experimental study of the amount of available energy in the reservoir crude and of energy losses in flowing wells. The return of surplus products to the reservoir has continued to be a satisfactory economic operation and the crude throughput capacity of the topping plant has been increased. The viscosity of residue returned to the reservoir is reduced before injection by regassing at 35 lb. per sq. in. absorption pressure with surplus gas. The pressure in the gas dome is falling at the low rate of one pound per annum. Haft Kel Field.—The delimitation of the main structure has proceeded; the oil-bearing area so far proved being about 50 square miles.

Jan 1, 1936

1876, PROF. RICHARD AKERMAN Stockholm, Sweden. 1913. DR. FRANK DAWSON ADAMS Montreal, Canada. 1909. PROP. RICHARD BECK Freiberg, Germany. 1905. ANDREW CARNEGIE New York, N. Y. 1906. DR. JAMES DOUGLAS New York, N. Y. 1888. PROF. HATON DE LA GOUPILLIERE Paris, France. 1966. SIR ROBERT A. HADFIELD London, England. 1888. PROF. HANS HOEFER Leoben, Austria. 1917. HERBERT C. HOOVER San Francisco, Cal. 1915.. JAMES FURMAN KEMP NEW York, N. Y. 1905. PROF. HENRI LOUIS LE CHATELIER Paris, France. 1913. EZEQUIEL ORDONEZ Mexico City, Mexico. 1909. ALEXANDRE POURCEL Paris, France. 1911. DR. ROSSITER W. RAYMOND New York, N. Y. 1911. PROF. ROBERT H. RICHARDS Boston, Mass. 1909. DR. ING. H. C. EMIL SCHROEDTER Dusseldorf, Germany., 1906. JOHN E. STEAD Middlesbrough, England. 1902. PROF. DIMITRY CONSTANTIN TSCHERNOFF Petrograd, Russia. 1910. PROF. TSUNASHIRO WADA Tokyo, Japan. 1907. CHARLES D. WALCOTT Washington, D. C.

Jan 1, 1917

Albin, B. R. Billings, Mont. 28 Amster, Nathan L 25 Broad St., New York, N. Y. '28 Bache, Jules S. 42 Broadway, New York, N. Y. 28 Barrett, C. P. 5338 Harper Ave., Chicago, 111. '28 Baum, Frank G., Cons. Hydro-Electric Engr Cassel, Shasta Co., Cal. '28 Bayless, William S. Russ Bldg., San Francisco, Cal. '28 Bean, Louis H.60 E. 42nd St., New York, N. Y. '28 Beatty, Roes J. 1105 First National Bank Bldg., Chicago, Ill. '28 Benwell, Oswald F. Hold Mags. '28 Beymer, Albert S., V.P., Keystone National Bank Pittsburgh, Pa. '28 Blumenthal, Hugo 44 Pine St., New York, N. Y. '28 Boettcher, Charles Ideal Cement Bldg., Denver, Colo. '28 Bowlus, Thomas H. Iola, Kan. '28 Brown, Colvin B. Chamber of Commerce, Washington, D. C. '28 Bart, Maxwell Struthers Southern Pines, N. C. '28

Jan 1, 1932

Albin, B. R Billings, Mont. '28 Amster, Nathan L 25 Broad St., New York, N. Y. '28 Bache, Jules S. 42 Broadway, New York, N. Y. '28 Barrett C. P. 5338 Harper Ave., Chicago, Ill. '28 Baum, Frank G., Cons. Hydro-Electric Engr Cassel, Shasta Co., Cal. '28 Bayless, William S. Russ Bldg., San Francisco, Cal. '28 Bean, Louis H. 60 E. 42nd St., New York, N. Y. '28 Beatty, Ross J. Room 604, 6 N. Clark St., Chicago, Ill. '28 Benwell, Oswald F. Hold Mags. '28 Beymer, Albert S., V.-P., Keystone National BankPittsburgh, Pa. '28 Blumenthal, Hugo. 44 Pine St., New York, N. Y. '28 Boettcher, Charles Ideal Cement Bldg., Denver, Colo. '28 Bowlus. Thomas H. Iola, Ken. '28 Brown, Colvin B. Chamber of Commerce Washington, D. C. '28 Burt, Maxwell Struthers Southern Pines, N. C. '28

Jan 1, 1932

By R. J. Grissom

PHOSPHATE deposits have been worked in many countries of central and south central Tennessee, but only ht ebrown rock deposits of Maury and Giles Counties will be discussed at any length in this articles, as all of the major opeations are now located there. They are: Mt. Pleasant District-Federal Chemical Co., Hoover and Mason Phosphae Co., International Minerals and Chemical Corp. (Maury and Giles Counties), Virginia-Carolina Chemical Corp. (formerly Charleston Mining Co.), and Victor Chemical Co. Columbia District-Armour Fertilizer Works and Monsanto Chemical Co. In the near future, the well-known, extensive deposits of blue rock in Lewis and Hickman Counties,also the brown rock in Hickman, Willamson, Summer and Davidson Counties, will again come into production. Certain physical peculiarities of the Tenessee deposit have played an important part in the design and use of mining and milling equipment.

Jan 1, 1944

By P. G. Salom

The manufacture of steel castings has become one of the important industries of the times. The late Mr. Alexander I,. Holley published in 1878, in the Metallurgical Review, an able paper, entitled "Solid Steel Castings," showing how all manner of castings could be made advantageously of steel. Mr. Holley had then but lately returned from the great iron and steel works of Terrenoire, France, which were engaged, I believe, almost exclusively on large castings, of a simple type, for the government,, and were repeating the same operation from day to day. These conditions are, as experience has shown, very different from those of ordinary practice in miscellaneons castings; and Mr. Holley might have been less confident if be had actually gone into the business. More than seven years have passed ; and as yet the magnificent possibilities held forth in his paper have not been realized. There are only six steelcasting establishments in the United States, and their total output of castings is certainly not as much as 20,000 tons per annum, and probably not more than 10,000 tons; whereas it should be over 200,000 tons to supply the needs of the country. A large number of so-called steel castings are made, however, which are nothing more than malleable iron. The best of these castings are made from a superior white pig, as low in silicon and

Jan 1, 1886

By Robert C. Freas, William H. Lane, David J. Krohn

Maysville, Kentucky, is the location of Dravo Lime company's new 9 070 mt(10,000 tons) per day limestone mine and 2 727 mt (3000 tons) per day calcination plant. This complex has been designed as a unit, and capitalizes on recent technological advances. Geologically the Dravo facility is.located on the eastern flank of the Cincinnati Arch, with the high calcium limestone being found at a depth of approximately 274 m (900 ft). A systems approach has been employed in designing and equipping the mine. This allows for maximum production while maintaining flexibility and versatility. All hydraulic drilling, large LHD equipment, and an extendable mine conveyor system are utilized in a five-part mining cycle. A modular concept modifies the room and pillar system to optimize ventilation. The limestone is calcined in three 5.18 x 61.87 m (17 x 203 ft) KVS rotary kilns with a design capacity of 909 mt (1000 tons) per day of lime per kiln. The kilns are coal fired and equipped with preheaters. Lime storage is provided by three 57 m (186 ft) high concrete silos with a combined capacity of 40 909 mt.

Jan 1, 1976

By E. F. Kingsbury

ONE of the well-known and important uses of the noble or precious metals has been for electrical contacts. In fact, the elements of this group, comprising gold, silver and. the six platinum metals, have been called "noble" because of their ability to resist heat and corrosion, properties which. were early found to be of importance in good contacts. Of these, platinum and its iridium alloys, palladium, and silver, have been extensively used. In recent years the electrical industry has been responsible for about one-eighth of the total consumption of the platinum metals in the United States. Information is not available as to what part of this one-eighth has been used for contacts but it is certainly an important one. SUBSTITUTES FOR PLATINUM During the past 20 years a considerable number of contact alloys have been proposed in the patent literature largely with the aim of more or less replacing platinum by gold or silver, and some of these alloys are finding increasingly widespread application as the reliability of their performance becomes established. From even the partial data at hand it appears that this substitution by the less precious metals has replaced at least one-half of the amount of platinum that the entire electrical industry would otherwise be consuming at the present time. While the subject is of considerable interest to the metallurgist it is even more so to the electrical engineer and it is surprising that the literature records no systematic and' comprehensive investigation along these lines. Practically all the scattered work on noble metal contacts has centered around platinum as a standard and has had two more or less distinct aims. One of these has been the replacement of platinum by cheaper materials, and the other, the development of materials of superior electrical performance. The merit, of a contact metal has been assumed to be dependent on its infusibility, and since the more precious metals have the higher melting points there has naturally been an association of the two qualities in the sense that the more precious were

Jan 1, 1928

By R. G. Treuting

Germanium single crystals strained in tension at 600°C slip on the {Ill} plane and, macroscopically at least, in the <110> direction. Deformation is in homogeneous: various localized rotations are observed, as is a banding consistent with secondary slip banding. The structure after deformation is polygonized with a domain size of about 2x1O-3 cm. In relaxation tests, an incubation period prior to flow is observed, of duration inversely related to temperature and applied stress. Under continuous loading, there is a sharp first yield point. A critical resolved shear stress therefore must be cited with respect both to temperature and to rate of loading. At 600°C, when loading proceeds at 2900 psi per min, it is 1310 psi. The yield point phenomenon is suggestive of Cottrell&apos;s solute atom atmosphere theory and five points of qualitative agreement with this theory are found. PLASTICITY of germanium at elevated temperatures has been reported by Gallagher,&apos; who ascribed it to slip on {Ill) planes and described some associated effects. Preliminary experiments with single crystals of silicon and germanium loaded as simple beams confirmed {ill) as the slip plane of both materials.V his was demonstrated by the standard technique employing traces on two surfaces of known angle on a deformed crystal of known orientation.3 These experiments did not fix the slip direction, since more than one glide system operated. Uniaxial tensile straining is preferred for this purpose in order to restrict slip to one predominant system and to provide an unequivocal determination of the orientation change with respect to the stress axis. Experimental Method Specimens were diamond-sawed from germanium crystals containing about 5x10-5 wt pct Sb prepared by the zone-leveling process described by Pfann and Olsen;4 these specimens measured about 81/2 in. long, 0.20 in. wide, and were of various thicknesses from 0.035 to 0.060 in. Prior to testing, a specimen was coated over 1 in. or more of length at each end with Apiezon wax, chemically polished (in a solution of 15 ml HF, 25 ml HNO,, 15 ml CH3COOH, and 3 to 4 drops Br2), and dewaxed in warm xylene. A brief re-etching after scribing through a complete wax coating with vernier dividers provided gage marks at 0.200 in. intervals on the polished surface. A specimen with grips soft soldered to the ends was passed through the furnace tube and the grips pinned to the tensile machine in series with a stress gage. The Schopper testing machine is best described by reference to the illustration on p. 107 of Schmid and Boas5 and is operated with the pendulum arm locked, fixing the upper head. Load is applied through the screw-driven lower head, manually or by reduced speed motor. The furnace is 21/2 in. long surrounding a 4x7/16 in. ID quartz tube and was positioned about the specimen to permit free motion. The inert or reducing atmosphere required was sufficiently provided by a flow of helium introduced at the center of the furnace tube, with the tube ends loosely plugged with asbestos paper. Surface corrosion was slight. The stress gage employs a Be-Cu strip with SR-4 units incorporated in a simple bridge network with provision for balancing and calibrating. The bridge output on loading is fed through a Leeds and North-rup dc amplifier to a Speedomax 10 mv recorder, and calibration is obtained by dead loading. Experiments of two types have been conducted. Most have been in relaxation at constant elongation. One stress-strain curve has been taken with the machine continuously driven. Following extension of a specimen, Laue X-ray photographs were taken to obtain the orientation change between deformed and undeformed regions, recorded on a single film by translating the specimen in a plane normal to the beam between exposures. Sequences of such multiple exposures were made on some specimens to include the entire orientation range on one film. Slip Direction To obtain a maximum orientation change with a single slip system, crystals of very closely <110> axial orientation were used. The classic determination of slip direction rests on establishing that direc-

Jan 1, 1956

By H. S. Martin

The Phosphate Recovery Corporation operates three flotation plants, Nos. 1 and 2 concentrators about three miles northeast of Mulberry, Florida, and No. 3 plant at Wales, Tennessee. These plants represent the first commercial phosphate flotation operation and are also believed to be the largest nonmetallic flotation operation in the world at the present time. The details of this paper will be confined to plant No. 2, this being the newest and largest concentrator in Florida, and the flow sheet being practically the same as at plant No. 1. The No. 3 plant has been operated but a short time and has been shut down since December, 1932, on account of the decrease in phosphate rock production. The phosphate washers usually are located centrally on a known deposit so that about two hundred acres of ground can be mined economically to each washer location. The washers are moved to new areas when the distance becomes too great for economical pumping. The flotation plants are built either adjacent to a washer, so that current debris may be utilized, or on the site of a former washer where there is sufficient accumulated debris available for mining, and the flotation plants must also be moved from time to time. Most of the water used in the Florida flotation plants is recovered after passing through a circulating system where most of the fine suspended matter is settled out, but some make-up water is obtained from deep wells near the plant. Power is obtained from the Tampa Electric Co. through the distribution facilities of the International Agricultural Corporation. Flotation concentrate is hauled from the plant by trolley over the International Agricultural Corporation&apos;s trolley system, to the drying plant at Prairie, one mile northwest of Mulberry. Ore Treated In the pebble phosphate district of Florida, the phosphate mineral, or collophane, is usually found in horizontal beds of varying thickness

Jan 1, 1935

By M. G. Benz

The superconducting performmce of diffusion-processed Nb3Sn is influenced by its micro structure. High isotropic transverse current density may be achieved in this material by a process which forms a precipitate of ZrO, within the Nb3Sn. FOR an ideal type-I1 superconductor, little or no transport current can be carried in the mixed state; i.e., little or no transport current can be carried above the lower critical field H,,, where the field penetrates abruptly in the form of current vortices or fluxoids, even though full transition to the normal state does not occur until the upper critical field H,,.&apos; Fortunately, nonideal type-I1 superconductors can be readily obtained and these carry large transport currents up to the upper critical field H. Both theoretical and experimental investigations have attributed this current-carrying capability for nonideal type-I1 superconductors to pinning of the fluxoid lattice by heterogeneities in the microstructure of the superconducting material. These heterogeneities may take the form of dislocations or dislocation clusters,2"5 grain boundaries: structural imperfections introduced by phase transformations; radiation damage,8"10 or precipitates.11"15 Nb3Sn formed by diffusion processing is a type-I1 superconductor. Heterogeneities are needed for high superconducting critical currents above H,,. This paper will cover: a) what the microstructure of diffusion-processed NbSn looks like; b) what changes in the microstructure take place when the system is doped with precipitates, and c) how these changes in microstructure influence the superconducting critical currents. EXPERIMENTAL Preparation of Samples. Diffusion processing was used to form the Nb3Sn. The procedure used was as follows: a) coat the surface of a niobium tape with tin; b) heat-treat this tape at a temperature above 930°C to form a layer of Nb3Sn at the Sn-Nb interface. Such a layer of NbsSn is shown in Fig. 1 The thickness of the NbsSn layer formed was controlled by the time and temperature of the heat treatment. The same general procedure was used for preparation of both undoped samples and samples doped with a precipitate. An additional step was included in the preparation of the doped samples which consisted of internal oxidation of zirconium to form ZrOn. The details of the doping process will be reported in a later paper. Sample Testing. The Nb3Sn tape samples were soldered to a copper or brass shunt. Current and voltage leads were then attached to the sample in the usual four-probe resistance measurement configuration. The sample was cooled to 42°K. In some cases it was cooled in the presence of a high magnetic field and in other cases with the field turned off. The results were the same for both cases. The samples were oriented in a configuration with field transverse to current but could be rotated such that the angle between the field vector and the wide side of the tape sample could be changed. Measurements up to 100 kG were done in a superconducting solenoid and measurements above 100 kG in a water-cooled copper magnet at the MIT National Magnet Laboratory. Once the test field was reached, the current in the sample was increased until voltage was detected across the sample. The critical current was taken as the current at which voltage was first detected in excess of background noise. In most cases this was 1 to 2 x 10~6 v for a— in.-wide sample carrying several hundred amperes with a in. separation between voltage leads and with a 10 "-ohm shunt resistance. RESULTS AND DISCUSSION Microstructure. Examination of the microstructure of the undoped Nb3Sn shows rather large-diameter (1 to 2 columnar grains growing outward from the niobium surface toward the tin surface. As the layer is made thicker by longer diffusion times, these grains grow longer. Few new grains are started. Transmission electron microscopy shows little or no second-phase material within the bulk of the Nb3Sn layer. The microstructure of a diffusion-processed NbsSn layer changes quite drastically when the system is doped so as to form a precipitate within the NbsSn layer. Instead of large-diameter columnar grains of NbaSn forming, smaller-diameter (0.5 to 1 ) equiaxed grains of Nb3Sn decorated with the precipitate form. Fig. 2 shows a transmission electron micrograph of a Nb3Sn layer doped with zirconium oxide. This layer has been etched so that one may look between the grains

Jan 1, 1969

By T. L. Berger, M. C. lnman, M. F. Rose

AFTER shock loading, mechanical twinning has been observed by several authors1-4 for a variety of fcc metals and alloys. It has been shown2,3 that low stacking fault energy materials deform primarily by the formation of mechanical twins and stacking faults during dynamic loading. Further, Inman, Murr, and Rose2 have shown that a correlation exists between the average hardness and the volume percent of mechanically twinned material in stainless steel. It has been observed in nickel&apos; that mechanical twins are produced during shock deformation if the peak pressure associated with the shock wave is greater than 350kbar. It is the purpose of this work to discuss shock-hardening mechanisms in nickel and to determine to what extent the initial condition influences the final response. The "flying plate technique" was used to generate planar shock waves with peak pressures as high as 710 kbar. The details of the technique5" have been discussed elsewhere and will not be repeated here. The material used in this study was polycrystalline nickel of 99.98 pct purity and had an initial grain size of 0.18 mm. Prior to any deformation, all samples were given a stress-relief anneal of 6 hr at 600°C in a vacuum furnace. After annealing, the initial condition of the samples was changed by cold rolling individual samples from 0 pct to a maximum of 80 pct reduction in thickness. This provided samples with controlled initial histories for shock deformation. Immediately after shock loading, the specimens were slowed and quenched by suitable arrangement of buffer material and water bath. This technique minimized specimen damage and the effects of shock heating on the samples. Since deformation twins in high stacking fault energy fcc metals are only produced at high stress levels, the initial defect configuration prior to mechanical twinning should greatly influence the number of twins formed. In fact, Zukas and Fowler7 have found that prestraining in iron and steel greatly suppresses the formation of mechanical twins during the shock deformation process. Following the methods of Warren and warekois8 and Cohen and Wagner,9 X-ray diffraction profile analysis was performed to determine the incidence of stacking faults and mechanical twins in the deformed nickel. Analysis was made on samples in the annealed, cold-rolled, shock-loaded, and cold-rolled—shock-loaded states. The estimated accuracy of the peak position measurements is *0.01 deg in 2?. Therefore the accuracy in the measurement of the relative peak shifts between the (400) and (222) diffraction line profiles is on the order of *0.04 deg in 2?. None of our measurements indicated peak shifts greater than 0.04 in 28. This would correspond to a fault density of -1 pct and sets the limit on the sensitivity of our instrument. Similarly, analysis of the shift in the center of gravity of the diffraction line profiles yields the minimum measurable value of the twin fault probabilitya to be -0.002. Fig. 1 shows mechanical twinning in nickel shock-loaded to 400 kbar. In this photograph, fault intersections are clearly visible. The thickness of the individual fault lamellae was determined from the image widths of their lines of intersections by the

Jan 1, 1968

By Frank S. Hurley

To comply with the California Mine Safety Orders pertaining to transportation of mine workers over mine railroads, the management of the New Idria mine in San Benito County, Calif., designed special man-cars. The new regulations, dated October 1958, make it mandatory for mine man-cars to be designed for carrying five or more men to and from the mine workings. At the New Idria mine, largest single producer of mercury in the U.S., each shift normally employs about 70 men. However, with the possibility of a future increase in the work force, seven man-cars were constructed with a total carrying capacity of 84 men. The general design of the mine man-cars was dictated by safety regulations plus the physical characteristics of the mine-low headroom, limited side clearance in haulageways, and track irregularities due to ground swells. The cars measure 10 ft long, 44 in. wide, and 50 in. high and were built at an average cost of $450 per car. All assembly work was done at the mine site.

Jan 7, 1960

By Albert J. Phillips

FOR the most part, recent changes in nonferrous physical metallurgy have been gradual and of a transition nature rather than abrupt modifications of existing methods. Development of new alloys containing vital constituents in what formerly would have been considered minute amounts has necessitated more precise control of metallurgical procedure than ever before. Realization of the remarkable effects of minute amounts of specific foreign elements in many alloys has brought about a revolutionary control in the selection of even the most commonplace raw materials. In addition, recognition of the widespread occurrence of precipitation hardness in metal systems, and the utilization of many of these, has emphasized not only the need for precise temperature control but also the necessity for considering the time factor in its effect upon properties in the treatment of most metals. These needs have caused the development and widespread installation of equipment that permits precision of control undreamed of a generation ago.

Jan 1, 1935

By Percy Gillie

THE Tralee preparation plant, owned and operated by the Semet-Solvay division of Allied Chemical and Dye Corp., is located on the Virginian railway, near Mullens, Wyoming County, W. Va., and the mine, which is in the Winding Gulf district, produces coal exclusively from Pocahontas No. 3 seam. The property, comprising 4900 acres, is leased from the Pocahontas Land Corp. Prior to 1930 four separate mines were operated in this tract, some having been started about 1916. Plans for the preparation plant were formulated soon after World War 11. Construction began in the spring of 1948, operation early in 1950. The plant was designed to be operated with minimum labor. It was equipped for production of first quality graded sizes of coal for house heating and 3/8x0-in. slack suitable for high-standard metallurgical coke. In the beginning, a thorough investigation was made of the property by means of core drilling, prospect openings, and sections from shallow mines on the property, as well as sections and analyses from mines in the immediate vicinity. After the extent of desirable coal had been established and the average seam section and nature of overlying and underlying strata had been determined, it was decided to install a system of mining which would load the full seam and would clean the product mechanically. Pocahontas No. 3 seam is characterized by draw slate and bone and rock partings. It was not known what the washing difficulties and cleaning plant requirements would be for processing the raw product of full mechanical mining. Arrangements were made, therefore, through the courtesy of the property owner, to obtain a large sample from a section of the mine along the adjoining property line. The

Jan 1, 1954

By Irving M. Symonds

COMPAÑIA Minera de Peñoles, S. A., at its Avalos unit operates a lead-zinc concentrator having a capacity of about 600 short tons per day. Lead and zinc concentrates are made by flotation methods. The concentrator is at Terminal de Providencia, in the state of Zacatecas, some 70 miles south of Saltillo, Coahuila. The Peñoles-Avalos railroad operating between the plant and Estacion Avalos, a distance of 6 miles, makes connections with the Coahuila and Zacatecas railroad, which in turn connects with the Nacionales de Mexico at Saltillo. The three railroads are each of different gauge, requiring the transfer of all supplies and concentrates at each junction. The mill operates on company ores, on ores from leased mines, and as a custom mill. The custom business is very small. The lead concentrates are shipped to company smelters at Monterrey, Nuevo Leon and Torreón, Coahuila. Since the European war, all zinc concentrates have been shipped to the United States. ORE TREATED The major source of ore supply is a group of four mines owned or leased by the company, some three miles south of the mill in the mountains, from which the ore is delivered to the mill by a gravity aerial tramway. Custom ore comes in by rail. The ores occur in chimneys. The upper levels contained oxidized siliceous ores of lead, copper, silver and gold, with varying amounts of zinc. These ores were direct-smelted. In the first two years of operation a good deal of the tailing loss was caused by the oxidized content of the ores milled. Much of the ore in the transition zones between the oxides and sulphides was not mined. The ores now being milled are clean, hard sulphides in a limestone gangue, with only occasional contamination of oxides. The lead and zinc sulphides are of coarse structure and are freed even above flotation sizes. The galena is usually "steel" colored, easily and quickly floated. When there is any oxidation, it is usually on the coarsest crystals. The zinc minerals vary a good deal in color; a resin sphalerite predominates but there are varying shades of brown marmatites. On an average, the zinc sulphides contain 64 per cent zinc. The only common copper mineral is chalcopyrite. Little is known of the occurrence of gold and silver. Waste minerals are mainly limestone and pyrite, both of which are barren. The ores vary from 20 to 35 per cent pyrite. Mill heads for the year 1940 and the first eight months of 1941 are given in Table I. [ ]

Jan 1, 1942

By L. F. Wright

Operations of these two mining companies have some superficial similarities-geographical location, production rates, comparatively large ore reserves; but any critical comparison of mining and milling procedures or of economics must take into account the striking differences in geological environment and mineralogy of the respective ore deposits. The properties are only about 20 miles apart on an upland surface of moderate relief (part of the Interior Plateau of central B. C.) which occupies an area east of Thompson River between the towns of Ashcroft and Merritt. Being in the "dry belt" of British Columbia, water conservation is necessary at both operations.

Jan 12, 1963

By F. Weinberg

In developing a mechanism for the solidification of metals from the melt, it has been proposed that solidification proceeds by the growth of platelets parallel to close packed planes. The evidence for this is based primarily on observations of decanted interfaces of lead1,2 and tin on which platelets 1 to 10 µ thick4 were observed. In recent observations of decanted eutectic alloys, 5,6 it was found that the eutectic structure on the decanted surface was markedly different than that of the bulk material, with the surface structure extending approximately 10 µ behind the interface.&apos; This suggested that, at least for these experiments, a residual liquid layer 10 µ thick had been left on the decanted interface, which solidified subsequent to decanting. If a similar thickness of residual liquid was left on the decanted surfaces in the lead and tin observations referred to above, then it is questionable to what extent the observed platelets can be related to the solid-liquid interface before decanting. The purpose of the present investigation was to measure the thickness of the residual liquid layer on a decanted surface of tin, using relatively standard decanting procedures. The technique used was to add approximately 200 ppm of Tl204 (PI) to the melted portion of a high purity (99.999 pet) bar of tin, which was being progressively melted from one end, and then decant during melting. Since only the melt contained the radioactive tracer, the activity emanating from the decanted surface could be used as a measure of the thickness of the residual liquid layer. Progressive melting was carried out in the same fashion as single crystal growth, namely, in a horizontal graphite boat, in an argon atmosphere, using a moving furnace. The decanting was done in two ways; 1) removing the furnace and suddenly dropping the melt end of the boat, and 2) suddenly jerking the solid away from the liquid by the action of a falling weight (estimated peak acceleration 3 x 105 cm per sq sec), using a split graphite container. In all cases the melt was vigorously agitated by bubbling argon through it. The activity of the decanted surface was measured through an aperture 1.5 cm by 0.5 cm in a lead shield with an Anton tube geiger counter. Assuming that the active layer on the surface had the same concentration of Tl204 as the decanted liquid, the thickness of the layer could be determined from the measured activity of the decanted material, and the relationship between activity and material thickness. The latter was determined by rolling some of the decanted material into foil and measuring the activity of multiple layers of the foil. The activity At of material of thickness t (in mm) was determined to be A, = Ao(1 - e-22.5t) where Ao is the activity of the bulk material. The results of the measurements of the thickness of the residual liquid layer for six decants are given in Table I. The variation in t is attributed to variations in the decanting procedure and the rate of melting, the latter being difficult to control because of the vigorous agitation of the liquid. The rate of melting was in the order of 2 cm per hr, estimated from the position of the solid-liquid interface during melting. The results indicate that a residual liquid layer of the order of 10 µ in thickness is left on the decanted interface in agreement with the observation on eutectic alloys referred to above. If the mixing of the liquid during melting is not complete, as was

Jan 1, 1962