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By Richard A. Sheppard

Zeolites-crystalline hydrated aluminosilicates of the alkalis and alkaline earths-are important rock-forming constituents in sedimentary rocks and are potentially valuable industrial minerals. They have a framework structure that encloses interconnected cavities occupied by the relatively large cations and water molecules. The cations, chiefly sodium, potassium, and calcium, and the water have considerable freedom of movement within the structure and give the zeolite their cation- exchange and reversible-dehydration properties. Some zeolites have essential contents of barium, strontium, or magnesium. The basic structure

Jan 1, 1975

By John J. Strohl, Henry J. Schwellenbach

This paper relates the results obtained by decreasing the size of feed to a rod mill screen circuit. As would be expected, added production was gained and a finer grind with no tonnage loss was made possible.

Jan 12, 1950

By H. H. Kaveler, W. R. Evans, Jack Tarner

The geological features, development history and engineering detail of the Shuler Field and the results of approximately two years of unitized operation of the Shuler Jones Sand Pool, were discussed in a prior publication.' The purpose of this paper is to present the results of pressure maintenance in the Shuler Jones Sand Pool after nine years of unit operation. GENERAL INFORMATION The Shuler Jones Sand Pool is located in and about Section 18, Township 18 South, Range 17 West, Union County, Ark. The pool was discovered .in September, 1937, unitized in February, 1941, and subjected to gas injection operations in July, 1941. Water was first returned to the reservoir in July, 1944. The reservoir is an anticlinal trap covering about 4,000 acres. The 154,000 acre-ft of sandstone initially consisted of approximately 150,000 acre-ft of productive oil zone and 4,000 acre-ft of gas-cap. The average depth of production is 7,400 ft. Maximum closure of the reservoir is 135 ft and the oil column lies between a gas-oil contact at -7,270 ft and a water-oil contact at -7,370 to -7,380 ft. The field is approximately four miles long. east and .west, and one and one-half miles wide. The sand grains are angular and vary from fine to medium size. The porosity of the sandstone averages 20.2 per cent. The specific permeability averages 400 md. Some zones have as high as 30 per cent porosity and specific permeability of 4,000 md. The reservoir rock is not uniform in character but consists of sandstone zones interspersed with shale. The variation in rock characteristics is evident in the electric log and core analyses presented in the original publication. Asphalt present in the pore space of the sandstone limited the reservoir to the southeast and apparently blocked any encroachment of water from that direction. The initial reservoir pressure at a subsea depth of 7,300 ft was 3,520 psi. The reservoir temperature was 198ºF. Initially, the solution gas volume was 765 cu ft per bbl and the reservoir volume factor was 1.45. The gas solubility and formation-volume-factors of the reservoir liquid are related with reservoir pressures above 300 psi as follows: Solution gas, cu ft per cu ft, S = 0.0334 P + 18.65 Formation volume factor of reservoir oil, FVF = 8.0 x 10 -5 P + 1.168 Gas volume factor, standard cu ft of gas equivalent to one cu ft of gas at reservoir conditions of temperature and pressure, F = .062 P - 4 Pressure (P) measured in psia. The equation for the gas volume factor presented above is based on a direct measurement of a sample of the gas and is a correction of that used in the original paper. The gravity of the oil produced is from 32 to 34" API. CALCULATION OF INITIAL OIL IN PLACE The Jones Sand production history is interesting because it lends itself to analysis by material balance. Production statistics from discovery of the Jones Sand through 1949 and material balance calculations of the initial stock tank oil in place are shown in Table I. The usual procedure in testing the application of material balance calculations is to compute the apparent initial volume of oil in place, using production and pressure information obtained at different time periods. If the apparent oil in place volumes computed increase with successive time periods, water encroachment is indicated and approximations must be mads to correct for its influence. The first requirement in utilizing such calculations is reliable reservoir pressure, accumulated gas, oil and water production, and PVT data. Calculations of apparent oil in place in the Jones Pool, based on field data

Jan 1, 1951

By W. R. Evans, H. H. Kaveler, Jack Tarner

The geological features, development history and engineering detail of the Shuler Field and the results of approximately two years of unitized operation of the Shuler Jones Sand Pool, were discussed in a prior publication.' The purpose of this paper is to present the results of pressure maintenance in the Shuler Jones Sand Pool after nine years of unit operation. GENERAL INFORMATION The Shuler Jones Sand Pool is located in and about Section 18, Township 18 South, Range 17 West, Union County, Ark. The pool was discovered .in September, 1937, unitized in February, 1941, and subjected to gas injection operations in July, 1941. Water was first returned to the reservoir in July, 1944. The reservoir is an anticlinal trap covering about 4,000 acres. The 154,000 acre-ft of sandstone initially consisted of approximately 150,000 acre-ft of productive oil zone and 4,000 acre-ft of gas-cap. The average depth of production is 7,400 ft. Maximum closure of the reservoir is 135 ft and the oil column lies between a gas-oil contact at -7,270 ft and a water-oil contact at -7,370 to -7,380 ft. The field is approximately four miles long. east and .west, and one and one-half miles wide. The sand grains are angular and vary from fine to medium size. The porosity of the sandstone averages 20.2 per cent. The specific permeability averages 400 md. Some zones have as high as 30 per cent porosity and specific permeability of 4,000 md. The reservoir rock is not uniform in character but consists of sandstone zones interspersed with shale. The variation in rock characteristics is evident in the electric log and core analyses presented in the original publication. Asphalt present in the pore space of the sandstone limited the reservoir to the southeast and apparently blocked any encroachment of water from that direction. The initial reservoir pressure at a subsea depth of 7,300 ft was 3,520 psi. The reservoir temperature was 198ºF. Initially, the solution gas volume was 765 cu ft per bbl and the reservoir volume factor was 1.45. The gas solubility and formation-volume-factors of the reservoir liquid are related with reservoir pressures above 300 psi as follows: Solution gas, cu ft per cu ft, S = 0.0334 P + 18.65 Formation volume factor of reservoir oil, FVF = 8.0 x 10 -5 P + 1.168 Gas volume factor, standard cu ft of gas equivalent to one cu ft of gas at reservoir conditions of temperature and pressure, F = .062 P - 4 Pressure (P) measured in psia. The equation for the gas volume factor presented above is based on a direct measurement of a sample of the gas and is a correction of that used in the original paper. The gravity of the oil produced is from 32 to 34" API. CALCULATION OF INITIAL OIL IN PLACE The Jones Sand production history is interesting because it lends itself to analysis by material balance. Production statistics from discovery of the Jones Sand through 1949 and material balance calculations of the initial stock tank oil in place are shown in Table I. The usual procedure in testing the application of material balance calculations is to compute the apparent initial volume of oil in place, using production and pressure information obtained at different time periods. If the apparent oil in place volumes computed increase with successive time periods, water encroachment is indicated and approximations must be mads to correct for its influence. The first requirement in utilizing such calculations is reliable reservoir pressure, accumulated gas, oil and water production, and PVT data. Calculations of apparent oil in place in the Jones Pool, based on field data

Jan 1, 1951

By Janshi Sen

VERTICAL-INTENSITY magnetometers, such as the Hotchkiss Superdip and the Askania vertical field balance, are now [ ] widely used, because vertical-intensity charts give definite information for the location of upper pole, dip and strike, and approximate shape of the deposit. Again, a slow and steady increase of dip over a large area indicates a large deep-lying deposit, while a large dip limited to a small area and falling away rapidly suggests a small and shallow one. The complication comes more from the richness of the ore. A large body of lean ore near the surface might produce the same vertical-intensity chart as a rich ore at depth. This paper presents a method for calculating the maximum depth of a single-pole deposit and another for a two-pole mineral body, by utilizing data of both vertical and horizontal intensities as obtained by a Thalen-Tiberg magnetometer. As shown on the left side of Fig. 1, lean ore, rich ore and a single pole produce the same magnetic field. The depth of the pole, [ ] h, can be calculated from the following relation: [h=a=tan¢=G-F h=aXFy] where G is the vertical intensity at point A due to the pole; F, the horizontal intensity of the same; and a, the distance from the point of maximum vertical intensity or the vertical projection of the pole on the surface to the point of observation A. If an entirely covered deposit is indicated by magnetic measurements and boring cost estimated from the calculated depth is so reasonable as to encourage drilling, the ore should be struck somewhere within the limit of the calculated depth by the borehole. A number of such points as A should be taken for calculation, erratic results should be rejected and the average figure used for cost estimation.

Jan 1, 1944

By R. W. Smith

There are many inconsistencies and gaps in available information concerning the mechanism whereby dodecylamine acts as a collector for quartz. The author compares the studies which have been made in correlating the contact angle with adsorption density on quartz over all pH ranges, and attempts to resolve some of the inconsistencies. In recent years much information has been obtained concerning the mechanism whereby dodecylamine acts as a collector for quartz. Fuerstenau,1 for ex- ample, has shown that adsorption density and zeta potential under some conditions, at least, can be correlated with contact angle and flotation rate. There appear, however, to be several inconsistencies and gaps in information available. One inconsistency involves trying to correlate contact angle with adsorption density on quartz over all pH ranges. Fuerstenau's correlation at a collector concentration of 4x10-5 moles per liter dodecylamine acetate and about pH 10 shows a contact angle of about 80 degrees occurring at approximately monolayer coverage. If Gaudin and Morrow's2 and Morrow's3 contact angle data for near neutrality (pH 6 to 7) are now compared with deBruyn's4,5 adsorption data on quartz in a similar pH range, it will be noticed that a contact angle of 38 to 40 degrees corresponds to complete monolayer coverage (at an amine concentration of approximately 10"3 molar). In fact even at an amine

Jan 1, 1963

By R. D. Sprague, C. B. Richardson

The year 1938 was the most active and successful in the history of the oil industry in southern Louisiana. Drilling showed a 16 per cent increase over that of 1937, with a total of 538 wells drilled, which yielded 315 oil wells, 19 distillate wells, 4 gas wells and 200 dry holes. Nineteen new fields were discovered during the year, all but three of which were completed by plugging back to sands previously drilled through. Electrical logging played a large part in these new discoveries as well as in the discovery of new sands during routine development of fields. Fourteen of the new discoveries produced oil, and five produced only gas and distillate. Southern Louisiana continues to lead the world in depth of drilling, which is in part due to the great thickness of comparatively young deltaic sediments near the coast and the existence of numerous sands. The present development is rather evenly distributed over a coastal strip 100 miles wide. New Fields North Tepetate, Acadia Parish.—Atlantic Refining Company's No. 1 Klumpp was completed for a new field through perforations from 7960 to 7970 ft. The initial production was 65 bbl. of 54" gravity distillate and 4 million cubic feet of gas daily through a 1/4-in. choke with tubing pressure of 2850 Ib. and casing pressure of 2930 lb. The well is in see. 12, 7 S., 2 W., just north of Tepetate field. It was drilled to a depth of 8705 ft. and plugged back for its final completion. Atlantic's NO. 2 was completed in a new sand at 8300 ft., also for distillate. South Crowley, Acadia Parish.—Humble Oil and Refining Company's No. 1 Boyd Finch was completed in July 1938, as an oil well through perforations from 7318 to 7325 ft. after plugging from a total depth of 10,222 ft. After making several hundred barrels of oil, the well went to

Jan 1, 1939

By C. B. Richardson, R. D. Sprague

The year 1938 was the most active and successful in the history of the oil industry in southern Louisiana. Drilling showed a 16 per cent increase over that of 1937, with a total of 538 wells drilled, which yielded 315 oil wells, 19 distillate wells, 4 gas wells and 200 dry holes. Nineteen new fields were discovered during the year, all but three of which were completed by plugging back to sands previously drilled through. Electrical logging played a large part in these new discoveries as well as in the discovery of new sands during routine development of fields. Fourteen of the new discoveries produced oil, and five produced only gas and distillate. Southern Louisiana continues to lead the world in depth of drilling, which is in part due to the great thickness of comparatively young deltaic sediments near the coast and the existence of numerous sands. The present development is rather evenly distributed over a coastal strip 100 miles wide. New Fields North Tepetate, Acadia Parish.—Atlantic Refining Company's No. 1 Klumpp was completed for a new field through perforations from 7960 to 7970 ft. The initial production was 65 bbl. of 54" gravity distillate and 4 million cubic feet of gas daily through a 1/4-in. choke with tubing pressure of 2850 Ib. and casing pressure of 2930 lb. The well is in see. 12, 7 S., 2 W., just north of Tepetate field. It was drilled to a depth of 8705 ft. and plugged back for its final completion. Atlantic's NO. 2 was completed in a new sand at 8300 ft., also for distillate. South Crowley, Acadia Parish.—Humble Oil and Refining Company's No. 1 Boyd Finch was completed in July 1938, as an oil well through perforations from 7318 to 7325 ft. after plugging from a total depth of 10,222 ft. After making several hundred barrels of oil, the well went to

Jan 1, 1939

By H. M. Chance

In the early part of 1893, I had occasion to make for the owners a professional examination of the Rich Patch tract; and, with their permission, I present in this paper, omitting the commercial portions of my report, those portions which may be valuable to future students of that region. Location, Topography And Geology. The Rich Patch tract comprises about 9000 acres, located about 3 miles west of Low Moor, on the Chesapeake and Ohio Railway, in Alleghany county, Va., and immediately adjoining the Low Moor property. In shape the tract is roughly quadrangular, being about 3 miles broad in a northerly and southerly direction, by about 6 miles long from east to West. Potts creek and Jackson river run along its northern boundary. It is drained by Hayes Gap run, Mill branch and Laurel creek, which flour north into Potts creek, and by Karnes creek, which flows northeasterly through the Low Moor property into Jackson river. The topography of the tract is shown by the accompanying map (Fig. I), and need not be described here. The valleys are cut down from 1000 to 1500 feet below the mountain summits, which generally reach an altitude of about 3000 feet above tide. The geological structure of the district is indicated by the geological cross-sections shown in Figs. 2 and 3. These sections show that the formations underlying the property extend from the Lower Silurian lin~estones up to the Devonian slates, including the numbers of the Paleozoic system of rocks as defined by the geological surveys of Virginia, Pennsylvania and New York, from No. 11. to No. VIII. • No. IX. Old Red Sandstone, No. VIII. Slates and Shales, Devoman-

Jan 1, 1900

By E. E. Wark, J. Rogers, I. W. Wark, K. L. Sutherland

SOAPS have been used as collectors for many years, but only in the last eight years have other long-chain paraffin salts been used. It may be anticipated that these newer collectors will be used mainly with nonsulphide minerals, for which the xanthates and similar compounds are of little value. On the other hand, the xanthates are both cheap and effective for sulphide ores and seem likely to retain their present eminence in this field. During 1938 and 1939 two of us (E. E. W. and I. W. W.) commenced a comprehensive investigation of the principles underlying the use of paraffin chain salts as flotation reagents. This research was sponsored jointly by the University of Melbourne and a group of Australian mining companies.[t] A broad, semi quantitative survey was then made of the field covered in the present paper. This was followed in 1940 by further work by one of us (K. L. S.). In 1941 the investigation was taken over by the Division of Industrial Chemistry of the Commonwealth Council for Scientific and Industrial Research, Australia. Discovery of some principles upon which are based the flotation of minerals by paraffin chain salts was followed by their application in the development of processes for the recovery of certain strategic minerals from their ores. Promising results in the flotation of cassiterite from various ores will be described in a subsequent paper. THE PARAFFIN CHAIN SALTS The basic requirements for a "collector" in flotation are that it should form a film over the surface of the mineral to be floated, and that this film should be orientated so that hydrocarbon (nonpolar) groups form the effective surface. When modified in this way, the mineral surface possesses some degree of air avidity. All investigators would agree with Taggart, Taylor and Ince23 that such a film can be produced only if the collector compound contains an active (polar) group to attract it to the mineral surface as well as the nonpolar group. One section of this large class of polarnonpolar compounds is the paraffin chain salts: CH3(CH2) „X where X signifies a polar group that ionizes in aqueous solution. Though the compound can ionize, it may be a weak or a strong electrolyte, and the hydrocarbon chain may be in the cation or the anion (Table I). Many compounds of similar constitution are available, but the usual polar groups are: -CO2Na, -SO3Na, -SO4Na, - PO4Na2, or an aminonitrogen group, the

Jan 1, 1946

By G. G. Sarkar

SHARPNESS of separation and washing efficiency are often confused. The sharpness index indicates the precision of a washing unit; the washing efficiency takes into account not only the unit's precision but also the washability characteristics of raw coal and the near-gravity materials at the effective density of cut. A sound basis for evaluating the sharpness index is essential in comparing the sharpness of separation attained by different cleaning units. Sharpness Index and Related Criteria: Washing plant sharpness of separation has been well represented by Hancock's efficiency chart and Tromp's curve of migrated materials. Some useful coefficients derived from Tromp's curve—the error area, probable error, and imperfection value—have been widely used to measure sharpness of separation. These are defined in a number of papers presented at the first and second International Coal Preparation Colsference held in Paris (1950) and Essen (1954).1-5 In evaluating the performance of a dense medium separator at four different gravities, Yan-cey and Greer6 bserved that even with similar operating conditions and the same size grading of feed, the imperfection value of a washing plant varies through a greater range than the probable error. The present writer also observed the same type of anomalies in comparing the imperfection values of one plant which were determined under almost identical conditions. He therefore devised a graphical method to evaluate a washing unit's sharpness of separation and define it by a single coefficient, which is substantially independent of coal characteristics under normal operation of the unit. Unlike imperfection value, the new coefficient can be expressed on a percentage basis. Coal preparation engineers generally agree that the amount of misplaced material resulting from any separation in a washing plant is almost directly related to the amount of +0.10 sp gr (near-gravity) materials. In actual practice, however, misplacement is not restricted to the 20.10 sp gr range. It will be evident from a study of Tromp curves that this misplacement often extends over unequal specific gravity ranges on the two sides of the actual density of separation. The same condition exists for near-gravity ash distribution and the resultant misplacement of ash units during any separation. But so far as the same unit is concerned, the total misplacements bear a definite ratio to the amount of near-gravity zone materials that is affected by misplacements. This ratio should be constant not only for various densities of separation but also for different qualities of feed coal treated in the same plant. This ratio, multiplied by 100, directly represents the inefficiency of the plant. When the plant inefficiency value is subtracted from 100, the re- ' sult is designated as sharpness index. Evaluating the Sharpness Index: The method of evaluating the sharpness index is explained here with reference to Fig. 1. Fig. 1 is a reproduction of the familiar diagram used by Cerchar of France to represent the inefficiency of a separation in terms of "triangle of errors," which is a measure of organic loss. It will be observed that the characteristic (yield/fractional ash) curve of the raw coal represented by GHAPR

Jan 1, 1958

By S. P. Kinney, C. E. Wood, T. L. Joseph

In connection with its investigations of the blast-furnace process, the Bureau of Mines, in cooperation with the Minnesota School of Mines Experiment Station, developed a 6-ton experimental furnace. Such a furnace was needed to determine the feasibility of producing ferroman-ganese from Minnesota manganiferous iron ores, a problem of national importance because of the present need for manganese in the steel industry and our small reserves of ferro-grade ores. Furnace operators are reluctant to use new or untried raw materials or to make decided innovations in practice on account of the financial hazard of experimenting with full-scale equipment. A small furnace which can be operated at a relatively low cost is particularly adapted for testing new raw materials and for determining the feasibility of decided innovations in practice. Laboratory experiments, plus whatever information may be available, are valuable but often do not indicate the net result of changes in an operation involving a large number of interrelated variables. From time to time the cooperation of the Bureau of Mines is solicited in connection with problems involving departures from normal procedure. Under these circumstances some sort of a practical demonstration is a desirable forerunner to full-scale operations which appear feasible after small-scale tests. The Aluminum Co. of America was interested in knowing the practicability of smelting a charge of bauxite, iron ore, and limestone, of proportions that would produce slag of the following composition: A1203, 47 to 48 per cent.; CaO, 41 to 42 per cent.; SiO2,4 to 5 per cent.; TiO2, 2 to 3 per cent.; FeO, 1 percent., and MgO, 1.8 percent. In addition to determining whether it was feasible to operate a blast furnace on slag approaching the composition given above, a quantity of slag was needed for a series of experiments that would show the relative ease and cost of extracting alumina from slag which could be made in the blast furnace, as compared to extracting it from raw bauxite. The value of the slag as a raw material

By A. A. Bauer, H. A. Saller, F. A. Rough, J. R. Doig

among uranium alloy systems are the U-Zr, U-Ti,and U-Mo binary systems, in that an intermediate phase, of limited solubility range, exists in each system. These intermediate phase alloys offer a promising field of investigation, both as binary alloys and as ternary alloy combinations. While a limited amount of work has been done on the binary alloys, none has been done on ternary combinations of these alloys. As a possible prelude to more intensive investigation of these systems, a study of the phase relationships between the 6 phases of the U-Zr and U-Ti systems was undertaken. The solid-state portions of the binary constitutional diagrams for the U-Ti,1 Zr-Ti,2 and U-Zr3 systems are shown in Fig. 1. The solid to liquid transformations are not shown, as these transformations were not studied in the ternary system. The phase designations employed are based upon those shown in the uranium constitutional diagrams. The crystal structures of the various phases are given in Table I. Experimental Materials and Methods The ternary section presented is based upon the results of thermal, metallographic, and X-ray analyses of a series of alloys ranging in composition between the phases of the U-Zr and U-Ti systems (U-74 atomic pct Zr to U-35 atomic pct Ti). After preparation of the alloys, thermal data were obtained. On the basis of these data, specimens were heat treated and examined metallographically. Specimens were then selected from those heat treated for X-ray determination of the phases present in what were considered critical phase regions. Alloy and Specimen Preparation—Alloys for this investigation were prepared from selected as-reduced uranium and crystal-bar zirconium and titanium. For nominal compositions, see Table 11. Charges were arc melted from five to seven times under a helium atmosphere, finally being cast into wire-bar form for fabrication. A zirconium getter button was used to clean the furnace atmosphere prior to melting. The alloys were homogenized 20 hr at 900 °C and furnace cooled. A portion of each bar was then removed for thermal analysis; the remainder was saved for fabrication. Alloys 8 through 14 were placed in steel tubes along with zirconium getter chips and, after flushing with argon, the tubes were welded shut and rolled at 1500 °F to a 50 pct reduction in diam. The remaining alloys were annealed 24 hr at ll00°F to insure transformation of the ? phase to the 8-U2Ti phase and were then hot rolled from a salt bath. Attempts to roll alloys 6 and 7 at 1100 °F were unsuccessful. Following this, attempts were made to roll pieces of alloys 1 through 5, which had cracked rather severely during casting, at 1200 °F, but these efforts were also unsuccessful. These alloys were, therefore, further treated in their cast and homogenized condition. All alloys were pickled to remove oxide formed during rolling. Thermal data were obtained on these alloys by conventional differential thermal analysis at a heating rate of 30C per min, and by a high-speed heating method at rates of approximately 10°C per sec. For the latter method of analysis, a 36-gage Chromel-Alumel thermocouple is spot welded between two slivers of alloy, the sandwich being en-

Jan 1, 1958

Jan 1, 1902

By R. E. McNulty, R. D. Heidenreich, C. H. Gerould

TIIE electron microscope techniques and their application to magnesium alloys that are to be discussed in this paper are the result of research at The Dow Chemical Co. over the past three years. The view- point underlying the work is not wholly metallurgical, but has evolved through a variety of problems related to the physics and chemistry of surfaces. It can be said that the interest and stimulus were closely associated with a desire to employ effectively the electron microscope in research concerning the properties of solids as related to their physical structure. Only a portion of this work will be described here, and, consequently, many points of interest and debate are of necessity either only briefly recognized or are completely omitted. As has been pointed out by Desch,1 a great deal of the knowledge of the structure of metals has been obtained through microscopic studies of the surfaces of metallic specimens prepared in a particular manner. This information, when added to that obtained by means of thermal, electrical, X-ray, dilatometric and other methods, has been of great value both from a theoretical and a practical view- point. With the introduction of new instruments such as the electron diffraction camera and the electron microscope, it would be expected that still more information could be obtained. These two instruments have in many instances been very effective when directed toward the investigation of metallic surfaces, provided the proper methods of surface preparation were employed. Experience shows that the problems of surface preparation greatly limit the general application of these instruments to metallographic studies. It was found necessary to discard the standard metallographic procedures in applying the electron microscope to magnesium alloys and to work out new methods, which were required to satisfy certain conditions. These methods are unique to magnesium only in the specific chemical reactions occurring during etching. The presentation of the methods and results will be ordered as follows: I. Electron Microscopy of Surfaces. 2. Surface Preparation of Magnesium Alloys. 3. Discussion of Microstructures. a. Pure Magnesium and Single-crystal Studies. b. Types of Precipitation. c. Some Common Structures. d. Special Micrographs and Techniques. e. Structure of Mg-A1 Solid Solutions. 4. Correlation of "Fine Structure" with Corrosion Behavior of Magnesium Alloys.

Jan 1, 1946

By J. S. Diller

In 1827, chromite was discovered near Baltimore by Isaac Tyson, Jr., who initiated the mining of chrome ore an:! later (1845) .the manufacture of chromium compounds in this country. From 1828 to about 1860 the United States, supplanting Russia, supplied chromite for most of the world. Chrome deposits were found also in California, and the Tyson Company shipped ore to Philadelphia by way of Cape Horn. In 1848, J. Lawrence Smith, an American in the employ of the Porte, discovered large bodies of chromite in Asia Minor. They were developed in 1865 and became the chief source of the world's supply for a number of years. The discovery of the large high-grade bodies in New Caledonia, and later in Rhodesia, with other foreign sources, gives at present an abundant supply for all demands. For a number of years before the great war, the United States produced only a few hundred tons of chromite annually, for local use, but during the war the demand for domestic ore resulted in a production of more than 82,000 long tons of crude ore in 1918, and it was demonstrated that the United States has reserve deposits equal to a war demand of several years' duration. Now that the war is over, the country is conserving its domestic supplies by employing higher-grade but cheaper ore from foreign countries. ChromiUm-bearing Minerals Oxides: Chromite-—chromic iron ore................ FeO.Cr2O3 Picotite—chromic iron ore................. (MgFe)O.(Al,Cr) Chromates: Crocoite—lead chromate................... PbCrO4 Phoenicochroite—basic lead ohromite........ 3PbO.2CrO3 Vauquelinite—phospho-chromate of lead..... 2(PbCu)CrOd.(PbCu)3P2O8 Sulfates: Redingtonite—hydrous chromium sulfate.... Knoxvillitel—hydrous basic sulfate of chromium.............................. Daubreelite-—iron-chromium sulfide (known in meteorites only)...................... FeS.Cr2S3

Jan 1, 1920

By G. D. Marshall, D. K. Sarin, V. E. Hampton

Ground support at the Thompson Mine emphasizes scaling, rock bolting and wire mesh screening on the backs and walls of all underground stoping and development areas and also full column grouted cable bolting in the bulk mining areas. This paper describes the equipment for the point anchored rock bolts as well as the full column cable bolts. Modifications in design and testing of all components and procedures has ensured a safe and efficient method of ground support for the mining conditions existing at the Thompson Mine.

Jan 1, 1983

By E. V. Daveler

The milling plant of the Alaska-Gastineau Mining Co. is located at the town of Thane, Alaska, on Gastineau Channel, 4 mi. south of Juneau and directly across the channel from the Ready Bullion mine of the Treadwell mines on Douglas Island. Previous to the organization of the Alaska-Gastineau Mining Co., in 1912, the milling was done at the stamp mill of the Alaska Perseverance Co. located at the mine in Silver Bow Basin. But the contemplated increase in production made it necessary to locate the mill on Gastineau Channel, as not enough water was available at the mine during the winter months, nor was there room for taking care of the large tonnage of tailings that would ultimately be discarded from the mill. Character of Ore The gold and silver values occur in quartz lenses associated with pyrrhotite, galena, arsenical pyrites, and zinc blende. These lenses occur in large bodies of slate, schist, and metagabbro, which also carry some valuable metallic contents. With the essential low cost of mining, it was necessary to mine large bodies of low-grade material containing the high-grade streaks. Of the minerals, pyrrhotite, the magnetic sulfide of iron, is predominant, and galena is the next sulfide present in quantity. The gold occurs free and coarse and associated with the iron sulfide in its finer state. The silver occurs with the lead or is alloyed with the gold. A chemical analysis of the ore shows Silver............ 0.10 oz. Magnesia......... 0.4 per cent. Silica............. 59.7percent. Sulfur............ 1.2 per cent. Iron.............. 5.2 per cent. Lead............. 0.1 per cent. Alumina.......... 21.4percent. Zinc............. 0.2percent.. Lime............. 5.0 per cent. Experimental Work Investigations at the old Perseverance stamp mill had developed the following points: Roughing concentration following stamping gives a fair recovery.

Jan 1, 1920

By W. B. Wise, H. D. Attra, W. M. Black

The purpose of this paper is to illustrate a comparatively new approach for solving a problem that has plagued oil producers for many years—how to make the most money with available field production capacity. In a very basic operation such as a top-allowable one-well field, a computer and staff of engineers are not required to determine that the best operation is to produce that well at its maximum for as long a time as it will produce. However, as the problem becomes more complex and the number of wells and number of reservoirs increase, it probably will be a wise choice to devote some engineering thought and calculation time to determine the best way to operate that field on both an ultimate and day-to-day basis. Continued developments in the field broadly referred to as "operations research" have led to a number of useful engineering analyses for optimizing field operational problems. One of these techniques, termed linear programing, is parlicularly interesting because of its potential applications to the study of complex oilfield operating problems. Linear programing is concerned with the problem of planning a complex set of interde~endenl activities in the best possible (optimal) fashion. A field application of linear programing is being used to maximize daily income from a multi-reservoir producing operation. The initial results of this study indicate that the linear programing technique (I) can be applied effectively to field problems, (2) can be used to detect unsuspected avenues for improving operations and (3) can effect a significantly improved means of controlling field operations through the use of the highspeed computer. INTRODUCTION The usual approach for studying complex field operational problems has been to look in detail at several basic plans suggested by judgement and experience and, then, to choose the best plan from those investigated. This approach is entirely satisfactory provided: (1) that judgment and experience alone will reliably pick the best or near the best program as one of the plans to be investigated; and (2), and most important, that the factors which control field production will not change. This paper deals with the large group of field operations which are at least one-step removed from a satisfactory solution using the conventional method of analysis. Problems such as pipeline- and gathering-system design, transportation studies, large field development projects and multi-reservoir producing operations fall in this latter category. To find the best program for handling these problems when the best program is not obvious, a complete optimization study is required, and high-speed computers are required to continually update the program once it is selected. Operations of this type have an extremely large number of possible solutions. However, only one will result in maximum economic return and, more important, this one program must be re-evaluated and adjusted constantly to accomodate such changing field factors as the number of producing days, the price of crude, the discovery of new reserves, declining reservoir pressure with subsequent decline in production and a host of other factors which characterize specific operations. One of the most widely used, direct methods of optimization is a numerical procedure termed "linear programing", which is designed to investigate systematically each of the possible solutions involved in a given problem, determining rapidly and uniquely the optimum answer. As implied by the name, linear programing requires that all field variables be either defined or expressed in a series of interdependent linear equalities or inequalities. These relationships are solved simultaneously, using a form of matrix solutions to determine the optimum values for each producing variable that will maximize net profits. The solution techniques used in a recent field case study is termed the "simplex method" and is discussed in full detail in Ref. 1.

By C. G. Dunn, F. W. Daniels, M. J. Bolton

IN recent papers on interface energies in metals¹,² the concept of an equilibrium of forces has been used in the measurement of interfacial tensions. Mathematically the equilibrium of three forces is given by the relations: where the 2's are the interfacial tensions (interface energies per unit area of interface) of three phases or grains meeting at angles 21 22 and 23 (212 relates to the 1-2 boundary formed by grains 1 and 2;223 to the 2-3 boundary, etc.). If these relationships are valid, one can calculate relative values of the interface energies from measured boundary angles on specimens which have been brought to equilibrium. Since Eq 1 may be derived through a mathematical process of minimizing the grain boundary energy under the restriction that the ?'s be independent of boundary orientation: the concepts of surface tensions and equilibrium of forces are not particularly essential. To deal with the general case involving dependence of boundary energy on boundary orientation, it becomes desirable to drop certain concepts formerly held (namely that energy per unit area is identical with force per unit length or surface tension) and to use the energy concept alone. It is appropriate, therefore, to use E in place of ? in deriving and using the more general equations that express the anisotropic nature of the grain boundary energy. Herring3# ' recently has derived the required general equations using the principle of minimization of energy. Specifying the boundary orientations in terms of angles (4) measured with reference to crystal axes within the grains, Herring's equations take the form E23 + E21 cos?8 + E12 cos?2 — sin ?12 + sin?2-?E12/?12 =O [2] where the partial derivatives are measured in the direction of counterclockwise rotation of the boundaries. Eq 2 implies that an infinitesimal displacement of the triple point along the 2-3 boundary produces no change in the boundary energy. Similar equations apply for infinitesimal displacements along each of the other two boundaries. From such equations Herring obtains the following general relationship (1 + E1 E2) sin?8 + (E2 — E1) cos?3 ________ E38______________ = (1+ E2 E8) sin ?1+ (E3— E2) cos ?1 __________^5____________[3] (1 + E sin ?2, + (E1 — E8,) COS ?2 1 E28 where E1 = 1/E23- E25 and PC and c8 have similar expressions. It is apparent that Eq 3 reduces to Eq 1 when the c's vanish. Eq 3 also reduces to Eq 1 when the E'S are all equal. Shockley and Read' have pointed out one limitation to these equations. When E plotted versus 4 appears as an energy cusp, as their theory requires, for example, for the energy near a twin boundary position, then Eq 3 (and therefore Eq 1 also) no longer applies if one boundary is in the minimum energy position. One of the equations of form Eq 2, however, applies if the infinitesimal displacement is along the boundary associated with the energy cusp. From the foregoing treatment it will be apparent that equilibrium angles alone are not sufficient in general for calculating relative interface energies.

Jan 1, 1951