Search Documents

By Thomas S. West

A gravel pack completion is described which, in addition to sand screening, permits the exclusion of water and gas from the oil production. A gravel pack composed of alternate layers of different particle sizes is employed which has horizontal but not overall vertical permeability to drilling mud. A packer is run on the tubing and set in the screen member, around which the gravel layers are placed. The hydrostatic pressure of a mud column prevents the entry of fluid above (or below) the level of the packer. The producing level may be changed by raising or lowering the tubing. Vertical coning is controlled by replacing the mud column with oil and continually injecting oil into the sand section above (or below) the packer. Three well histories with this completion are described in detail. Statistics on the first 100 completions of this general type are given. INTRODUCTION Gravel pack type completions have heretofore been almost exclusively for the purpose of preventing sand production. This paper describes and presents well data on a gravel pack procedure which is primarily a selective completion method. Although complete sand screening is achieved, the exclusion of gas and water is the primary objective. The application of this procedure is therefore not limited to unconsolidated sands. Application to hard sand or limestone reservoirs is equally feasible. GRAVEL PACK PROCEDURE Figs. 1 and 2 illustrate the gravel pack procedure employed. The gravel is placed by means of the frangible disc type dump bailer shown by Fig. 1.' This bailer has its lower end closed by a plate glass or steel rimmed cement disc. This disc breaks when the bailer passes over the liner allowing the gravel to be deposited around the liner. The liner employed is usually 2 3/8 in. to 2 7/8 in. OD and 1.995 in. or 2.07 in. ID (ID of 2-in. tubing or 2-in. line pipe). Two tvDes,. of slotted sections have been employed. One type employs horizontal hacksaw cut or milled slots of about 1/32 in. width opposite the producing section. The other type employs the same type,. of horizontal slot. but slots are placed in groups of six at intervals of about 8 in. A cage composed of half round vertical bars, spaced apart, is then welded to the pipe over the slotted sections. This liner has the bottom end closed, usually by bull plugging. The upper end is closed, while placing the gravel, by a cap which is held in place by means of a shear pin. This cap has a mandrel attached to it which extends downward inside of the liner to within a few inches of its lower end. The top of the liner cap is formed to fit a releasing type wire line core barrel overshot. The liner is lowered to bottom on the wire line by means of this overshot and released. The length of the liner is usually suffi- cient to extend to about 20 ft above the highest level to which gravel is to be placed, the upper end of the liner always being in the casing. The dimensions of the liner and bailer are such with respect to the casing size that the bailer will always pass over the liner. After releasing the liner the bailer is run to bottom. Passage of the empty

Jan 1, 1951

By H. D. Kynor

By the term mechanical mining is meant that operation, or series of operations, that replace the hand methods of mining. The first undercutting machine to operate in anthracite was placed in the Butler mine of the Hillside Coal and Iron Co., Dec. 23, 1910, by the Sullivan Machinery Co. The first Jackhamer used in the anthracite field was installed at the Wadesville colliery of the Philadelphia & Reading Coal and Iron Co. in Oct., 1912, by the Ingersoll-Rand Co. The first longwall conveyor was installed at the Dodge mines of the Delaware, Lackawanna, & Western Coal Co. in March, 1912. The first mechanical scraper equipment was installed in the Seneca mines of the Lehigh Valley Coal Co. in January, 1914. The amount of anthracite mechanically mined since the first mining machine was installed in 1910" is as follows: Penna. Coal Co. D. L. & W.. ScRanton Temple Hudson YeaR and Hill- Tons Coal Co., Coal Co., Coal Co., Total, side Coal Tons Tons Tons Tons and Iron. Tons 1920................ 372,737b 367,000d 322,892 74,127 371,878 1,508,634 1919................ 950,786 no record 306,616 81,575 319,356 1,658,333 1918................ 917,778 744,966 24,880 44,756 288,781 2,021,161 1917................ 757,940 838,800 5,050 57,279 164,180 1,823,249 1916................ 286,780 860,663 13,960 114,173 101,475 1,377,051 1915................ 428,819 592,169 8,253 1,029,241 1914................ 219,188 153,896 373,084 1913................ 171,505 1912................ 124,267 124,267 1911................ 40,319 40,319 1910................ 1,184 1,184 a A slightly greater production was obtained than here indicated, as the tonnage from individual operations is not shown. b Decrease due to strike conditions in 1920. c Does not include tonnage of D., L., & W. d D., L., & W. decrease in 1920 due to having fewer mining machines in operation. There are about 150 undercutters in use in the anthracite region, 80 mechanical loaders, and 10 longwall conveyors.

Jan 1, 1922

By I. Lazaro Roche, J. Brunner, J. Busto, X. Martin, J. B. Decitre, S. Gaffet, F. Hivert

"Muon tomography allows investigating the subsurface. Muons being penetrative, the attenuation of the muon flux depends on the quantity of matter the particles travel through, hence on the rock density and thickness. For the Temporal Tomography of rock Density using Muon Measurements (T2DM2) project, the muon flux measurements are performed in LSBB URL (http://www.lsbb.eu) in order to study the hydrogeological processes in the unsaturated area of Fontaine-de-Vaucluse karst aquifer. The suitability of the muography for this study is here numerically demonstrated. In parallel to these simulations, muon flux measurements are carried out in the LSBB galleries by means of a set of four scintillator tanks and Micromegas detectors are developed. These detectors, here described, are adapted for underground and confined spaces as well as other environments. Their performances are particularly interesting and should contribute to the expansion of muon tomography in new application fields. INTRODUCTIONMuon tomography or muography is a method to image large volumes by measuring the absorption of cosmic ray muons. It uses, in a passive way, a natural radiation source: the muons which are charged particles produced in the atmosphere. Primary cosmic rays interact with atmospheric nuclei and produce a huge number of secondary particles, including muons. Due to their important mass compared to electrons, they are highly penetrating, reaching several hundreds of meters below the surface. Their attenuation depends on the quantity of matter they cross. That's why they are used to investigate the subsurface, muon absorption measurement allowing to estimate the in-situ density of the rock.Georges (Georges, 1955) proposed in 1955 to use the muons in order to study the density variations caused by the overburden over an Australian tunnel. In 1970, Alvarez (Alvarez, 1970) imaged the internal structure of Chephren Pyramid thanks to this method. The muon tomography has been particularly developed for volcanology (Nagamine, 1995; Tanaka, 2007; Lesparre, 2010; Carloganu, 2013) over the last twenty years. Since the beginning of the 2010's, a growing amount of projects that proposed to use the muons in various fields get underway: the CO2 storage (Kudryavtsev, 2012), the exploration of Mars (Kedar, 2013), etc."

Jan 1, 2015

By C. J. Pritchard

The Office of Mine Safety and Health Research (OMSHR) investigated ways to increase mine airflow to underground metal/nonmetal (M/NM) mine working areas to improve miners? health and safety. One of those areas is controlled recirculation. Because the quantity of mine air often cannot be increased, reusing part of the ventilating air can be an effective alternative, if implemented properly, until the capacity of the present system is improved. The additional airflow can be used to provide effective dilution of contaminants and higher flow velocities in the underground mine environment. Most applications of controlled recirculation involve taking a portion of the return air and passing it back into the intake to increase the air volume delivered to the desired work areas. OMSHR investigated a Nevada gold mine where shaft rehabilitation was in progress and one of the two main fans was shut down to allow reduced air velocity for safe shaft work. Underground booster fan operating pressures were kept constant to maintain airflow to work areas, inducing controlled recirculation in one work zone. Investigation into system behavior and the effects of recirculation on the working area during times of reduced primary ventilation system airflow would provide additional information on implementation of controlled recirculation into the system and how these events affect M/NM ventilation systems. The National Institute for Occupational Safety and Health monitored the ventilation district when both main fans were operating and another scenario with one of the units turned off for maintenance. Airflow and contaminants were measured to determine the exposure effects of induced recirculation on miner health. Surveys showed that 19% controlled recirculation created no change in the overall district airflow distribution and a small reduction in district fresh air intake. Total dust levels increased only modestly and respirable dust levels were also low. Diesel particulate matter (DPM) levels showed a high increase in district intake mass flow, but minor increases in exposure levels related to the recirculation percentage. Utilization of DPM mass flow rates allows input into ventilation modeling programs to better understand and plan for ventilation changes and district recirculation effects on miners? health.

By John G. Oldsen

Passive cable bolting and active cable trusses have been used in roof support for more than two years Excellent roof control has been experienced by many coal operations. This paper covers the new and innovative developments in cable support systems and their application in mines. Multiple cable bolts, tensioned cable bolts, coal rib wrapping, and other cable applications will be covered.

Jan 1, 1997

By Carl Swartz

METALLURGISTS differ considerably in their opinions regarding the effect, if any, of small amounts of iron pyrites, or other iron compounds on zinc sulfide ores during the roasting operation. As a result, the literature on this subject expresses many conflicting ideas. The ore, previously crushed to pass through a one-millimeter screen, dries in the roasting kiln, losing water up to 200° to 300° C. At 150° C. iron pyrites begin to lose sulfur. As the temperature increases, while the ore is passing to the hotter part of the furnace, the sulfur burns to sulfur dioxide, leaving the metals as zinc oxide and ferric oxide. These two substances then interact to form zinc ferrite, a compound, yellow brown in, color, having the general characteristics of a spinet Like magnetite, another spinel, zinc ferrite is insoluble in alkalis and dilute acids. As a result, when leached with 10 per cent. sulfuric acid solution zinc values tied up in this compound remain behind. HISTORY In the electrolytic recovery of zinc from its ores, the roasted ores are usually leached with a 10 per cent. sulfuric acid solution. When the zinc ore contains iron pyrites as an impurity in an appreciable amount, the actual yield of metallic zinc is much lower than a theoretical calculation would indicate. Further, losses of zinc are, in a rough way, directly proportional to the amount of iron pyrites or other iron compounds present. When the iron is present in the ore in an isomorphous relation to the zinc, as in the case of a marmatite, a greater amount of zinc remains insoluble than when present as a true pyrite or marcasite. Work on the insoluble residues obtained from leaching of the calcines shows that the zinc lost is intimately tied up in this residue. Some investigators have suggested a definite compound, such as zinc ferrite, others merely a mixture of zinc and iron compounds.

Jan 1, 1927

By R. B. Campbell

One of the three power plants that will be in the Curecanti Unit of the Bureau of Reclamation's Colorado River Storage Project is the power plant at Morrow Point Dam. Presently under construction, the Morrow Point Power Plant is between Gunnison and Montrose on the Gunnison River in west-central Colorado. (Fig. 1). Morrow Point Dam will be a thin, double-curvature, concrete-arch dam, 465 ft high and will impound 120,000 acre-ft of water. Two 60,000-kw hydroelectric generators will be housed in an underground power plant in the left abutment just down- stream from the dam. The power-plant chamber will be an unlined opening 205.5 ft long, 57 ft wide and 65 to 134 ft high. The arch-type roof with a rise-to-span ratio of 1 to 4 will be supported with rock bolts and chain link fence. A description and discussion of the design considerations for the power-plant opening and rock bolt design are given by William H. Wolf, Gilbert L. Brown, and Ernest D. Morgan in "Morrow Point Under- ground Powerplant," ASCE Power Division Specialty Conference, Denver Colorado, August 18-20, 1965. The Morrow Point site is in a moderately active region of mild earth- quakes, as evidenced by recent earthquakes in 1960 and 1962. Therefore, the Bureau of Reclamation undertook an investigation of the effects on the underground power-plant chamber when subjected to an earthquake. The art of earthquake engineering has been directed primarily at developing methods of analyzing the nature of ground surface motions and designing surface structures to resist damage from vibrations impressed on the structure by the ground motions. The mechanism of straining an underground cavity by an earthquake

Jan 1, 1968

By J. G. Schofield, C. G. Tan, R. J. Ord

"Most electric furnaces in the nickel and copper smelting industries are still fitted with conventional electrode holders which consist of water-cooled electrical contact clamps and a pressure ring. The water cooling exerts a significant cooling effect on the electrode column. The importance of controlling the temperature of the Soderberg electrode paste at the contact clamp area is examined, using in-plant experience and computer simulation of the paste melting and baking process. In addition to the effect of water-cooling, the effect of other variables, including the mantle air temperature, the electrode current, the furnace freeboard temperature and the electrode slipping rate are discussed. Ways in which the variable heating conditions in the paste melting zone can be controlled are outlined.IntroductionIn most non-ferrous electric smelting operations, the breakage of Soderberg electrodes is an infrequent, isolated occurrence. Occasionally, however, a rash of breakages may be experienced on a particular furnace for what appears to be no obvious reasons. The extent of the breaks may not exhibit a uniform pattern; sometimes the break may be less than half a metre above the electrode tip; at other times it may be at or just below the roof level. The latter type of break is, of course, the most dangerous since it is closest to the non-baked, weak portion of the electrode paste column. No matter where the breaks occur, they result in abnormal furnace power, charging and tapping conditions and loss of production while the new electrode section is slipped and baked. On a six-electrode furnace, breakage on one electrode has the immediate effect of reducing the total furnace power by one-third. On a three-electrode furnace, the effect is more drastic, one half of the power being lost."

Jan 1, 1995

By R. L. Stephenson

The effect of fabrication variables on the creep-rupture properties of TZM (Mo-0.5 pct Ti-0.08 pct Zr-0.03 pct C), Cb-TZM [columbium-modified TZM (7140-1.5 pct Nb-0.5 pct Ti-0.8 pct Zr-0.05 pct C)], and TZC (Mo-1.2 pct Ti-0.25 pct Zr-0.15 pct C) has been studied at 982º. 1093º, 1204º, and 1315°C for rupture times up to 1000 hr. The creep tests were performed in vacuum creep furnaces, employing cold-trapped oil-diffusion pumps, operating at pressures 2 X 10-7 tory. After-test chemical analyses showed no significant changes in interstitial content. The creep-rupture properties of TZM, fabricated according to current mill practice, were determined in the stress-relieved and in the re crystallized conditions to provide control data. Specimens of TZM, Cb-TZM, and TZC fabricated according to each of two experimental fabrication schedules were then tested. The schedules differed in terms of in-process annealing temperatures and warm -working temperatures. The data make several conclusions evident. Fabrication variables do indeed have a profound effect on the long-time creep-rupture properties of molybdenum alloys. Strengths of these alloys compare very favorably with those of other refractory metal alloys in the temperature range studied. FOR several years we have been engaged in the evaluation of the creep-rupture properties of promising refractory metal alloys. We consider the determination of these properties to 1000 hr at several temperatures necessary for a valid comparison. Such an evaluation indicated that the creep strengths of Mo-0.5 pct Ti and TZM (Mo-0.5 pct Ti-0.08 pct Zr-0.03 pct C) compare favorably with those of other refractory metal alloys. Tensile and recrystallization data of other investigators1,2 show an effect of fabrication variables. More specifically, those fabrication schedules which produce high strength through work hardening exhibit the least thermal stability. A similar conclusion was reported by perkins3 for Cb-TZM. This would lead one to expect that, in terms of creep, those materials showing higher strength at short times and low temperatures would exhibit lower strength at long times and high temperatures. If these expectations were fact, a substantial improvement could be made in these alloys by optimizing their fabrication schedule in terms of their anticipated service temperature. We therefore undertook a study of the effect of fabrication variables on the long-time creep properties of TZM, Cb-TZM (Mo-1.5 pct Cb-0.5 pct Ti-0.08 pct Zr-0.05pct C) and TZC (Mo-1.2 pct Ti-0.25 pct Zr-0.15 pct C). MATERIALS All materials used were supplied by the Climax Molybdenum Co. of Mich. Our original intention was to test the same heat of each alloy in different conditions. Fabrication difficulties prevented this; however, heats with nearly identical analysis were selected. The compositions of the materials used are listed in Table I. All materials were supplied in the

Jan 1, 1970

By Wm Price

THE object of this paper is to present a survey of some of the physical properties of sheet nickel silver when subjected to cold rolling and when annealed at temperatures extending from 350° C. throughout the commercial annealing range. A number of alloys were taken from stock and analyzed. Four of these, representing low nickel and high nickel both with and without lead, were chosen for the tests. The analyses were as follows: ALLOY COPPER, LEAD, IRON, NICKEL, MANGANESE, ZINC, PER CENT. PER CENT. PER CENT. PER CENT. PER CENT. PER CENT A 64.68 Trace 0.194 - 6.73 0.06 remainder B 65.82 1.27 0.227 6.17 0.06 remainder C 65.44 Trace 0.345 17.83 0.08 remainder D 65.60 1.08 0.238 17.77 0.06 remainder These alloys were rolled in accordance with regular mill practice to approximately No. 6 B. & S. gage. The bars (which were then coiled) were annealed together in a mill muffle and afterwards pickled in a 10 per cent. sulfuric-acid solution and cold rolled in stages of approximately .one number (B. & S.) at a time to No. 18 B. & S. gage. After each stage, suitable samples were set aside for physical tests. Additional samples were chosen for tests after the bars were rolled to Nos. 8, 10, 12, and 14 gage. These samples were annealed together in the mill muffle and, after pickling, were finished on 0.050-in. gage, yielding a series of specimens 2, 4, 6, and 8 numbers hard for the subsequent annealing tests. Tensile test pieces 9 by 1 in. (22.9 by 2.5 cm.) were cut from both lots and the central portion was milled to give a test section 2 ½ in. long by ;Z in. wide. A distance of 2 in. was marked off on the edge of each specimen with light punch marks. In the case of the annealed alloys, Erichsen test pieces 4 by 2 1/2 in. were also taken.

Jan 10, 1920

By Jim Sandford

The South Bulga Colliery longwall operation, owned and operated by Cyprus Coal Australia. Oakbridge Pty. Ltd., and located near Singleton, NSW, is currently operating under an average 80-ft-thick (24-nt) sandstone unit residing immediately above the coal seam, resulting in sudden and severe face weightings. To date, nine severe weightings have occurred at the property (within Panels 3, 4. and 5), three of which resulted in face closures accompanied by significant equipment damage and several weeks of downtime. The remaining six events nearly resulted in face closures, incurring single-pass vertical convergence of up to 8 in (200 mm) along the pan line. In an effort to mitigate and/or eliminate the occurrence of these severe weighting events, mine management has established an in-house program to immediately address the geotechnical and operational mechanisms underlying rapid weightings, as well as specific measures to mitigate these events on future panels. In support of this in-house effort. NSA Engineering Pty. Ltd., is assisting the engineering staff at South Bulga in developing a more aggressive face monitoring program. The aim of this program is to provide weighting occurrence predictions sufficiently ahead of time to ensure that operational controls are optimized prior to attempting to mine through potential weighting areas. This paper reviews the occurrence of weightings to date at the South Bulga Colliery as well as the latest developments in shield monitoring technologies to forecast these events in near-real time.

Jan 1, 1999

By T. J. Smolik, Harman, D. W. Fuerstenau

By means of electrokinetic measurements, the surface properties of the aluminosilicate polymorphs (sillimanite, andalusite, and kyanite) and also mullite have been found to depend on the ratio of A10 bonds to SiO bonds in the surface. The Al-toSi ratio in the surface is dependent upon the crystal lographic properties of the mineral, which in turn determine coordination numbers of A1 and of Si, cleavage characteristics, and density of the various solids. Mullite with a greater bulk Al-toSi ratio has the highest zpc of the aluminosilicates. By treatment in dilute acids or by cycling between acidic and basic solutions, alumina is selectively dissolved from the surface of these orthosilicates. This shifts the apparent zpc to lower pH values as the fraction of SiO groups in the surface increases. Thus, surface properties can be altered by procedures that alter the A l-to-Si ratio in the surface. Flotation of these aluminosilicates results from electrostatic interaction of the collector ions with the mineral surfaces. As a result, flotation response shifts in accord with any shift in apparent zpc by pretreatment. Separation of minerals by flotation is based on differences in the physicochemical properties of their surfaces.'-3 For many minerals, adsorption of flotation collectors results from their functioning as counter ions in the electrical double layer at solid-water interface. In such systems, separation depends on differences in the zero point of charge (zpc) of the various minerals. The zpc is defined as the concentration of potential determining ions in solution at which the surface is uncharged. The potential determining ions for inorganic oxide-water interfaces are hydrogen and hydroxyl.4,5 This work is concerned with the effects of crystal structure, composition, and surface preparation on the surface properties and flotation behavior of aluminosilicates. Differences resulting from crystal structure were studied by measuring electrokinetic potentials and determining the flotation behavior of three different aluminosilicate materials having the same chemical composition (Al2O3 SiO2), namely andalusite, kyanite, and sillimanite. Furthermore, the effect of the Al2O3-to-SiO2 ratio on flotation behavior and surface properties was investigated by including synthetic mullite, 3A12O3 .2SiO2. Gaudin and co-workers 6,7 have clearly shown how crystal structure determines the native floatability of certain minerals. Those solids in which the surface is comprised mainly of broken residual bonds possess naturally hydrophobic surfaces. It was found by Bakakin8 that for a number of oxidized lead minerals, differences in floatability were due to the distance of Pb atom from the surface. Only limited work has been done on relating electrical properties of surfaces to crystal structure and composition. Healy et. a1.9 found that the zero points of charge of various manganese dioxides ranged from about pH 1.5 to pH 7.5, and these differences in the zpc's were interpreted in terms of the atomic packing in the various crystals. The research presented here clearly shows that crystal structure and chemical composition do affect the surface properties of aluminosilicates and, in addition, that these effects can be altered by changing conditions under which the surfaces are prepared. CRYSTAL STRUCTURE OF THE ALUMINOSILICATES Sillimanite, andalusite, and kyanite are composed of regionally metamorphosed rocks differing mainly in degree of metamorphism. All three minerals have the same chemical composition, Al2O3 - SiO2, of which sillimanite is the high temperature polymorph and kyanite and andalusite the lower temperature polymorphs. Andalusite and sillimanite crystallize in the orthorhombic system while kyanite crystallizes in the triclinic system. The structure of these three minerals is essentially chains of aluminum-oxygen octahedra linked laterally by silicon and aluminum. The arrangement of these chains in the three minerals is shown in Fig. 1.l4

Jan 1, 1967

By Milton E. Wadsworth, W. Martin Fassell, William H. Dresher

A study of the rate of dissolution of molybdenite (MoS2) in alkaline solution was carried out under carefully controlled conditions. Effects of temperature, oxygen over-pressure, and KOH concentration were evaluated. Studies were made in the temperature range 100°C to 175°C and in the pressure range 0 to 700 psia of oxygen. Under these conditions molybdenite was found to leach according to a linear mechanism. Both oxygen over-pressure and KOH concentration were found to control the rate of leaching. The mechanism has been explained in terms of adsorption of oxygen at the molybdenite surface followed by configurational rearrangement of the adsorbed molecules. The hydroxyl ion dependency is believed to be diffusion-controlled. Laboratory batch studies have shown that molybdenite can be readily dissolved in alkaline solutions under moderate conditions of temperature and pressure. Commercial application of this process to the production of ferro-molybdenum and molybdenum chemicals is promising in view of the ease of dissolution of molybdenite and the relatively noncorrosive conditions involved in the process. HIGH temperature-high pressure techniques have long been used to great advantage in the organic chemical industry, the petroleum industry, and the paper industry. Only recently, however, have these methods been used to extract metals from their ores on a commercial scale. The Chemical Construction Corp., together with interested producers of nickel and cobalt, has done much to develop methods of producing nickel and cobalt powders by the use of high temperature-high pressure techniques.' The Howe Sound Co. is currently operating a plant near Salt Lake City in which the new Chemical Construction Corp. technique is applied to cobalt-arsenic sulfide concentrates. In this method the concentrates are leached in a dilute solution of sulfuric acid under air pressure at a high temperature. Near Edmonton, in Alberta, Canada, the Sherritt Gordon Co. is also using the new method in conjunction with its ammoniacal leach process.' National Lead Co., at Fredricktown, Mo., is operating a process similar to that of Howe Sound. In spite of the rapid growth of high temperature-high pressure hydrometallurgical processes, there has been very little work done on fundamental principles involved in this type of process. Conse- quently the literature lacks any significant data in this field. Oxidation of pyrite,3 phalerite,4 galena,5 and recently molybdenite" in alkaline solutions has been reported to some extent. This investigation was initiated, therefore, to broaden the application of high temperature-high pressure hydrometallurgy and also to contribute some insight into the basic mechanisms of oxidation in an aqueous medium under these conditions. In addition to the immediate consequences of these processes much valuable information remains to be learned about fundamental reactions when they are carried out at temperatures and pressures slightly higher than those normally encountered. Leaching of molybdenite by alkaline solutions under oxygen pressure has recently been reported in the Russian literature by E. S. Usataya,8 who found that leaching rate increased with an increase in the pH of the solution—the strongest effects being observed at a pH of 10—and also with an increase in temperature. Usataya also has reported the formation of a protective film on the surface of the molybdenite when the leaching solution was weakly alkaline, neutral, or acidic. He believes that this oxidation process explains the migration of Mo+ + in the oxidation zones of molybdenite ore deposits and the subsequent impoverishment of the ores. Equipment: The high temperature-high pressure reaction unit used in this work was especially designed for kinetic studies of this nature, emphasis being placed on accuracy of measurement and precision of control. As details of the unit's construction and operation have been discussed elsewhere,7 Only basic features and principles of operation will be discussed at this point.

Jan 1, 1957

By J. E. Ostberg, G. Phragmen, A. Hultgren, S. Wohlfahrt

Detailed study was made of a number of rimming ingots, both low and high carbon, and especially upon effects of superimposed air pressure. Requirement to suppress core bubbles is between 10 and 15 atm; at 6.5 atm freezing was in semikilled manner and at 3 atm, steel was of rising type. Probable mechanism of freezing under various conditions is discussed. AN earlier paper' reported an investigation made by a committee for studying rimming steel ingots appointed by Jernkontorets in Stockholm. The present paper is the outcome of some further work done by the same committee. Since the characteristics of ordinary rimming steel are connected closely .with the amount of gas liberated during freezing and since this amount of gas is governed by the pressure, it was considered of interest to ascertain in what manner and to what extent definite pressures applied to the top of the liquid steel in the mold would affect the solidification process and the consequent structure of a rimming steel of ordinary composition. The experiments were made at the Domnarfvets Steel Works. The steel was made according to normal practice in a 4-ton Rennerfelt electric furnace. Ferromanganese was added in the furnace; no aluminum was added, with one exception. Analyses of the four heats are given in Table I. The top-poured ingots measured about 12 in. sq x 48 in. and weighed about 1300 lb. One or two ingots of each heat were allowed to solidify under pressure, using a special device for admitting compressed air to the upper closed part of the mold, as shown in Fig. 1. A heavy plate sealed with asbestos was bolted to the top of the mold. The plate had a tapered aperture for pouring. Immediately after pouring the hole was closed by a wedged plug, and compressed air was admitted through a hole in the plug. Because of some delay in applying the plug, full pressure was not reached immediately. The pressure was adjusted to the desired value as indicated by a manometer. In order that the interior of the ingot might have the benefit of the pressure, the freezing of the top crust was delayed by a refractory lining applied to the top part of the mold, Fig. 1. Ingots were also cast from each heat without applied pressure, and with and without refractory lining at the top. Axial sections of ingots were cut either of the whole ingot or of some part of it of special interest; sections were polished and usually etched.' To facilitate description of structures the following terms may be used for different types of ingots solidified under gas evolution: 1. Box-hat or boot-leg ingot: Abundant gas evolution during casting and during rimming; no rim holes. 2. Normal rimming ingot: Lively gas evolution during rimming; usually rim holes in lowest part of

Jan 1, 1952

By W. E. Lindquist

Roasting of refractory gold ores has the primary goal of oxidizing sulfides and organics to improve gold recoveries prior to leaching. Commercial installations currently utilize bubbling and circulating fluidized beds. The principle of flash roasting is aimed at a more cost effective method of whole ore roasting for large throughput applications. Results of pilot plant testing and scale up to commercial design will be discussed in further detail in this paper.

Jan 1, 1993

"An atmospheric process for the synthesis of scorodite(DMSP®)has beendeveloped,in which ferrous ions were oxidized by oxygen gas in the presence of pentavalent arsenic ions. Under optimum conditions, the synthesized scorodite (FeAsO4?2H2O) was well crystallizedand the crystals were faceted; the particle sizes were as large as 15 to 20 µm. In thisstudy, iron (II) sulfate heptahydrate (FeSO4·7H2O), arsenic (V) acid (60mass%H3AsO4) solution, and distilled water were used to prepare the original experimental solution (700 ml), in which the contents of Fe(II) and As(V) were 55.9 g/L and 50.0 g/L, respectively. The effects of various synthesis conditions, such as the type of oxidizing gas (oxygen or air), gas injectionrate, temperature, and the initial pH of the solution, on the size and shape of the scorodite particles wereinvestigated. From the experimental results, the changes in the shape of the scorodite particles wereclarified for each synthesis condition.INTRODUCTIONDOWA has developed a processfor synthesizing well-crystallized scorodite (FeAsO4•2H2O). Theprocess is named andtrademarked as DMSP® (Fujita et al., 2008; Fujita et al., 2008; Fujita et al., 2009; Fujita et al., 2009; Fujita et al., 2009, Kubo et al., 2010). In this process, oxygen gas is injectedinto a sulfuric acid solution containing large amountsof As(V) and Fe(II). Facetedscorodite crystals as large as 15–20 µm weregeneratedthrough the pre-formation of a gel-like precursor. However, it is known that the synthesized scorodite particles become smaller and more aggregatedwhen the synthesis conditionsdeviate from the optimumconditions.In this study, the effects of various synthesis conditions, such as the type of oxidizing gas (oxygen or air), gas flowrate, temperature, and initial pH of the solution, on the size and shape of the scorodite particles were investigated. The experimental resultsclarified the changes in the shape of the scorodite particles for each synthesis condition."

Jan 1, 2016

By Marcel R. Daly

The writer has devoted a number of years to practical operations and to the study of geology in the oil fields. In consequence, he has been brought to investigate the theories advanced to account for the accumulation of oil and gas in commercial deposits. It is the result of these investigations and his personal conclusions that he wishes to sum up in this paper. The writer is an advocate of the organic origin of petroleum found in pools. He has been led to believe that the present theories of oil and gas accumulations are incomplete and, in certain respects, incorrect, although they may embody certain elements of truth; that the forces that are called upon to explain the movement are only secondary forces in the process, and insufficient, by themselves, to cause this movement; and that the phenomenon of accumulation is of much larger order than heretofore admitted and bears an intimate relation with the general as well as with the local deformations of the crust and is a direct consequence and a mechanical effect of these deformations to which the term " diastrophie " has been applied. As a complement to this theory, the writer offers a new interpretation of the "rock pressure" and of the mechanism of the "sealing up" of this pressure in oil and gas pools. The Anticlinal Theory The theory most generally accepted to account for the accumulation of hydrocarbons in commercial deposits is the anticlinal or structural theory. This theory, the principles of which have been laid down by I. C. White, Orton, Winehell and others, and which has since been modified and perfected, is too well known to need a detailed statement. A clear interpretation of it may be found, in the paper of W. T. Griswold, in Bulletin No. 318 of the United States Geological Survey, and the reader is

Jan 1, 1917

By Charles S. Barrett, Robert F. Mehl

A study of the structures arising from the decomposition of the ß solid solutions in the Cu-Zn and the Cu-A1 systems is of peculiar interest in the study of the mechanism of precipitation from solid solutions. It is possible in these alloys, by varying the composition within the ß field, to precipitate from the same basic lattice phases having different lattice structures. It has been rather generally assumed heretofore that the type of structure originating from the decomposition of a solid solution— the Widmanstätten structure—-is determined by the lattice structure of the parent solid solution alone. In the first paper of this series1 evidence was advanced which threw doubt upon this hypothesis; but definite proof of the correctness or incorrectness of the hypothesis should be forthcoming from a study of these alloys, for if the structures originating, for example, from the precipitation of the a phase from ß and of the ? phase from the ß in the Cu-Zn system should be shown to be crystallographically different, the hypothesis would necessarily be held as definitely disproved. Furthermore, the newer proposal enunciated in the first paper of this series—that the origin of the Widmanstätten structure lies in a cooperation between the lattice of the parent solid solution and that of the precipitate-—which at present seems the only a1ternative hypothesis, would in such an event be given added weight. The work here reported shows that the Widmanstätten structures originating in the precipitation of the a phase from the ß and in the precipit'at.ion of the y phase from the y in the Cu-Zn system are indeed crystallographically different; and incidentally presents some new descriptive information on the Widmanstätten structure from a more general point, of view.

Jan 1, 1931

By H. B. Smith, B. Egererg

In a previous paper1 the authors dealt with the physical properties of cold-rolled and heat-treated Britannia metal of the approximate composition Sn, 91 per cent., Sb, 7 per cent. and Cu, 2 per cent. It was found that cold rolling to more than 50 per cent. reduction produced a continuous softening of the metal when measured by the Brinell machine, whereas the Shore instrument indicated increased hardness; that the strength of the material followed the Brinell hardness and that the metal therefore became weaker the more it was cold-rolled; and further, it was found that hardness and strength could be largely restored to the cold-rolled metal by "baking" for about one hour at any temperature between 200" and 450" F., the melting point. The higher the baking temperature, the more effective was the heat treatment as far as increased hardness was concerned. It seemed to be of little importance whether the metal was soaked or not at the baking temperature for a great length of time and the rate of cooling seemed to be immaterial. The present paper deals with the same alloy and more particularly with the resistance towards various forms of stress — tensile, bend and deep drawing. The metallography of Britannia metal has in part also been covered and an explanation attempted for the abnormal behavior of this alloy. Tensile and Bend Tests Two ingots 73/4 in. wide, 11 in. long and ¾ in. thick were cast from the same pot. One ingot was cold-rolled in one direction to a strip 0.241 in. thick, which furnished the tensile test specimens; the other ingot was rolled in the same way to 0.253 in. and furnished the specimens for the bend tests. The ingots were cast as described in the previous paper and cold-rolled in six passes.

Jan 1, 1930

Coal was known in this county before 1819, but there is no record of its use before that year. In that year a furnace, the first one built in the northwestern countries, was put in blast on Bear Creek; it was built to use coke and its first blast was with this fuel, which was made in heaps, but the blast was too weak and the furnace chilled after two or three tons of iron had been made. Charcoal was then substituted, and this use of coal ceased.1 In November of the same year a resolution was adopted urging state aid for a road from Kittanning to. Hamilton, New York: "that this road will increase the trade and industry of the whole county, between Pittsburgh and the New York line; and that our soil will in consequence be better tilled, our mines of coal, of iron and of salt, be better wrought, etc."2 In 1828 an advertisement of lands situated near Freeport on the Allegheny River and contiguous to the canal nearly completed between the Kiskiminitas and Pittsburgh stated that they contained "large and never failing springs, Coal in abundance, and a great deal of Fine Timber."3 In 1830 there were said to have been 24 salt wells in this county producing 327,000 bushels of salt, chiefly on the Kiski and Allegheny Rivers. In 1837 there were a number of wells in the vicinity of Freeport. As all the salt works on the Conemaugh River, were using coal long before 1830,4 it is safe to say that a considerable tonnage of coal was used for some years in these plants. In 1837 a tract of land in Clarion Township having a new saw mill and abounding "in Stone Coal" was offered for sale,5 and also one in Toby Township having "an abundance of the best quality of iron ore and stone coal."' In 1839 an advertisement in the Pittsburgh Mercury said

Jan 1, 1942