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Jan 1, 1941

By Howard C. Dunkle

Various factors can affect the quality of B1112 and B1113 steel as produced in a bessemer plant; among them: vessel-charging practice, blowing practice, ingot-pouring practice, ingot delivery-time practice, pit-heating practices, and ingot-rolling practice. Evaluation of the influence of ingot delivery time on quality has been chosen as the subject for this paper because this time is completely within the control of the operator, and on this particular factor there is a tremendous amount of information in the dusty archives of the average steel plant. In order to know how much improvement can be made and when attention should be directed to other factors that influence quality, in the continual struggle for improvement, the effect of ingot delivery time must be accurately evaluated. Once this is done, the importance of other variables can be accurately obtained, thus eliminating the necessity of resorting to opinions that are of doubtful value at best. In the study described herein, extensive use was made of the statistical card system as a method of determining the effect of ingot delivery time as a quality factor in bessemer screw-stock grades by simple direct correlation. The value of this statistical method as a means of accurately determining the influence of various factors has been amply demonstrated by Work1 for the bessemer process and by Hand and Gould2 and Fetters and Chipman3 for the open-hearth process. The quality records of 300,000 tons of bessemer screw-stock billets were used in this study of the effect of ingot delivery time on the rejections for breaks, pipe, check and seams. The reduction in the number of rejections for poor quality reduces the costs and increases the productivity per man-hour. The operator today, more than ever before, must know how to keep costs down, how to do it most quickly and in the best way, and how to obtain the highest quality in line with the ever increasing demands of the customer. It is necessary for him to know the individual relations and interrelations between various factors affecting the quality of the manufactured product if he is to produce material that will meet competitively the cost, performance, and quality demands of the trade. SIGNIFICANCE OF STEEL MANGANESE, MIXER SILICON AND STEEL SULPHUR AS QUALITY FACTORS In order to obtain the highest grade of material it is necessary to control many factors-not just one or two, as operators

Jan 1, 1945

By C. P. Besse, G. W. Osborne

Drilling operations on the Gulf of Mexico continental shelf are following two general plans. The first plan placed all buildings. equipment, and materials on a large platform while the second copies Lake Maracaibo drilling methods by placing a minimum of equipment on the platform and using a floating drilling tender or drill barge anchored adjacent to the platform in an attempt to take maximum advantage of flotation in an effort to reduce costs. A complete power rig, mud pits, pipe racks, and small auxiliaries have been placed on the platform as shown in Figure 1, to assure proper handling of drilling operations under the most adverse weather. This has the economic advantages of eliminating the fabrication of a large structure, a material reduction of rigging up time on each structure. and elimination of delay time on equipment while quarters and equipment placed on the tender are being rigged up. These factors have certainly proved their economic value in drill barge operations in the Louisiana and Texas coastal area. Naturally the heart of such an operation is the anchorage. This anchorage, to permit taking advantage of maximum economies. must hold the ship in a relatively fixed position under the following weather conditions: (1) Winter northwesters (2) Southeasterly gales (3) Severe rain squalls In hurricane weather all operations must be suspended regardless of method of operation and the floating tender will, if possible, be moved to a protected location. However, in case of an emergency the floating tender should be prepared to swing with the wind and seas on a single anchor as there is considerable doubt that either ship or anchorage could withstand the severe strains imposed by fixed anchorage in hurricane weather. Northwesters are reported to have developed wind gust velocities as high as sixty miles per hour and steady winds of approximately forty-five miles per hour. Fortunately these winds do not travel a great distance over water before arriving at our location, and, while they can possibly develop seas approximately eight feet high, the waves are short, and if taken on the bow or stern of a ship 250 feet or more in length they should not present a difficult problem. On the other hand southeast gales having a long fetch and maximum steady wind velocities of approximately thirty miles per hour can possibly develop long swells approximately twelve feet in height. These should develop the most severe anchorage problem. To combat these waves any workable anchorage plan should permit maneuvering the ship in such a manner as to head the bow or the stern into the seas and still maintain contact with the structure. Rain squalls develop wind gust velocities as great as sixty miles per hour. However, they are local and the seas have not been a source of great trouble. To permit continuous operation the anchorage must be able to withstand these winds broadside to the ship as the wind direction often changes radically in a very sliort time. All of these weather conditions are dangerous to small craft, deck cargoes,

Jan 1, 1949

Jan 1, 1929

By T. F. Morse, R. Lundstrom, A. J. Brammer, D. Peterson, M. Cherniack, T. Nilsson, J. D. Meyer, E. Toppila, G. Neely, N. Warren

HAVIC is a collaboration of investigators from North America, Sweden, and Finland having a scientific mandate from NIOSH, to study the exposure response relationship between vibratory tool exposure and adverse health effects. Five cohorts, the Suomossalmi forest workers cohort, Volvo truck cab workers, Connecticut shipyard workers, and matriculating dental hygiene students and experienced dental hygienists have been under study. In the case of shipyard workers, there was survey and tool exposure data from 1988, although detailed subject testing was only available within the timeframe of the study. The truck cab assembly workforce was an inception cohort that had been followed from 1994 along with age-matched controls. The Finnish forest workers had cumulative health data on a cohort (n=52) that had been studied from 1976. For a subset of these subjects, there was detailed tactometry testing in 1990, 1995, and 2003. Accordingly, there was historical as well as new prospective data for the industrial cohorts. The Suomossalmi cohort was reassembled only for our study, which precluded follow-up evaluation and because of retirement is almost certainly the last time this historic group will be studied. The study features are: • Characterization of the exposure response relationship for hand-arm vibration through a study design, incorporating multiple cohorts, some having existing historical data, • Selection of cohorts to include different types of vibration: oscillatory (forest workers) impact (truck cab workers), high frequency (dental hygienists) and mixed (shipyard workers), • Inclusion of two inception cohorts: dental hygiene students and Swedish truck cab workers, • Methods for multi-site and historical integration A description follows. [ ] Methods The study included surveys, physical evaluation, and a selection of battery of “best tests” (cold challenge plethysmography, multi-frequency tactometry, segmental sensory nerve conduction velocity [SNCV]1,2,3) applied across groups to quantify responses to exposure. Exposure monitoring included exposure characterization through daylong data logging at the individual level. Workers at each site were instrumented with a microcomputer-based Vibration Exposure Monitoring (VEM) system, developed at the Biodynamics Laboratory of UCHC and about the size of a police walkie-talkie, to record user-specific tool-operating times, vibrations, and grip forces throughout all, or a representative part, of their workday. More specifically, data logging methods involved the direct monitoring of work cycles, involving tool operation time and measures of tool vibration, namely the root-mean-square (RMS), root-mean-quad (RMQ), and root-mean-oct (RMO), and grip forces, each calculated per minute. For this study, the questionnaire was homogenized with other vibration studies4,5,6. Cross-translation was directed by the multi-lingual investigators, and then reviewed by the study team. To extend comparability with future international studies, questions were also added from the Vibration Network (VINET) draft questionnaire, the product of a European

Jan 6, 2006

By Eugene P. Pfleider, Jared Scofield

During the past ten years, the trend on the Mesabi Range has been toward the establishment of integrated operations which mine, concentrate, and pelletize the large reserves of magnetic taconite. However, since the supply of open-pit ores of acceptable quality is by no means inexhaustible, it has been proposed that it be supplemented by developing the magnetic taconites that extend down dip past the economic limits for open-pit methods. In Phase I of a long range study, Pfleider and Yardley1 collected information on the general character of the Mesabi iron formation at depth and proposed that an underground lane-and-pillar mining system be considered to extract those high grade layers where they might exist over a considerably areal extent. An approximate cost estimate was included initially, with the thought of later developing a feasibility study as time permitted.

Jan 9, 1967

Jan 1, 2004

By M. Geoghegan

Under the provisions of the U.N. Law of the Sea Convention Ireland is likely to have mineral rights to an area of continental shelf some six times its present land area. Apart from the major potential hydrocarbon basins which are currently the focus of active commercial exploration, little is known about the mineral resources of this vast area. In recent years a variety of mineral resources however have been identified from the coastal region. These include Sand and Gravel aggregates, Calcaraeous Algae (Lithothamnion), Heavy Mineral Sands and Coal deposits. The potential also exists in the coastal zone for buried placer deposits and base metal deposits. Several million cubic metres of gravel and hundreds of millions of cubic metres of sand have been identified by the Geological Survey of Irelands (G.S.I) Marine Unit off the east coast. The greater part of these deposits lies within the 10 metre depth contour and are easily recoverable. Irish aggregate needs at present are well supplied by onshore Pleistocene glacial deposits. Commercial interest in offshore deposits is in supplying coastal areas which are locally poor in aggregate and major coastal construction works. The possibility of supplying the large British and Continental European Market nearby also exists.

Jan 1, 1988

As already announced, the Arizona Meeting of the Institute is to be held from the 18th to the "25th of September. There will be a special train from New York City to Arizona and return, to take members and guests of the Institute to the meeting., The Committee in charge consists of Walter Douglas, Chairman, Cleveland E. Dodge, John C. Greenway, Arthur S. Dwight and Julius Kruttschnitt, Jr., and while the plans of this Committee are not complete, it may he announced that 'the train will be run with the requisite number of Pullman, dining and baggage cars to accommodate those who desire to go, which will accompany the party during the entire week of the Arizona Meeting as per the following program, including, of course, the visit to the Grand Canyon. It is especially desirable that the Committee should know, at as early a date as possible, the number of those who desire to make the trip; and those who desire special accommodations such as drawing rooms, state rooms, etc., are especially requested to communicate as soon as possible with the Secretary of the Institute, stating the number in their party.

Jan 6, 1916

By Frank W. Reinmiller, Edward S. Hsia

Earth bottom thickeners are generally considered to be the lowest cost solution for thickener bottom construction presently available to the mining industry. In addition to the capital cost advantage, these basins have proven to be watertight structures providing trouble-free operation for indefinite periods of time. During the past 15 years, some 18 of these thickeners have entered service with no particular problems encountered in porphyry copper operations, counter-current decantation in a gold cyanide plant, and other similar applications in mineral processing. In the course of this work, technological advances have been realized in the procedures for engineering and construction of these units to assure watertight basins and achieve all possible economies in construction.

Jan 8, 1977

By D. Y. Geng, S. S. Peng

Surface subsidence of two longwall panels, one with a private residence and the other with an arch bridge, was monitored over a period of 1 to 1' ½ years. Surface subsidence data were analyzed in terms of zone of advance influence and delay angle of maximum subsidence velocity. The variational characteristics of both features coincide with the periodic weighting at the advancing longwall face. Surface heaving in the subsidence process can also be attributed to periodic weighting. It was found that residential damages occurred when subsidence velocity exceeded 4.5 mm/day (0.15 ft/day). The effects of locating structures on the panel center and near the gob edges are illustrated. The effect of mining on ground water was also discussed. Finally, methods of reducing structural damages are recommended.

Jan 1, 1984

By F. M. Makarinsky

"This paper describes the conversion of conventional froth flotation cells to open-trough type bank cells, with 'buried' vertical metal partitions. These changes have resulted in: total froth removal along the full length of each bank of cells; extended flotation cell retention times; and has extended the life of the metal components, particularly towards the upper flotation cell areas.INTRODUCTIONOver the past twenty years, the flotation cells used at Falconbridge Limited, Sudbury operations concentrators, have gone through major physical changes. The various concentrators generally started with 100 cubic foot Denver Sub 'A' flotation cells. From these units, we progressed to 'converted' DR units, and/or Denver DR units, if purchased new. (Figures 1, 2, 3)In 1980, the Strathcona concentrator started to pay more attention to the 'front end' rougher flotation cells. Initially, the converted DR flotation cells had 'cut-outs' removed (Figure 4) at all upper vertical cell partitions, towards the ff9th lip areas, in order to get additional froth removal."

Jan 1, 1985

By H. J. Levinstein, H. J. Guggenheim

RbFeF3 is a transparent ferromagnet with a large faraday rotation which permits the direct observation of magnetic domain structures in bulk crystals. If the position of dislocations within the crystal were known a study of domain wall dislocation interactions would be possible. In this paper an etch pitting solution is described which gives a one-one correspondent between the etch pits and the dislocations intersecting the (100) surfaces of RbFeF3 crystals. In addition, RbFeF3 is shown to have sufficient plasticity so that known arrays of dislocaticms can be put into the crystal. It is concluded that RbFeF, is an ideal material for the investigation of domain wall dislocation interactions. THE influence of lattice defects on the motion of domain walls in ferromagnetic materials has been studied extensively both theoretically and experimentally.4 The experimental data obtained has been qualitative in nature due to the lack either of a quantitative knowledge of the magnetic domain array in the material or of the nature of the dislocation configuration in the material. At room temperature RbFeFJ has the cubic perovskite structure. It is ferromagnetic below 86°K.5,6 It is also transparent and has a large faraday rotation in the magnetic state.7 The domain structure of this material is observable in three dimensions in crystals which are millimeters in thickness.' Since RbFeF3 satisfies the requirements of having an easily visible three-dimensional magnetic domain structure, it was of interest to determine if the dislocation structure of the material could be determined and if the material was sufficiently plastic so that dislocations could be introduced into the as grown crystals. This is a report of the results of that investigation. EXPERIMENTAL PROCEDURE The crystals of RbFeFs used in this experiment were grown by a technique described elsewhere.5 In order to obtain flat strain-free surfaces, the samples were first cut to the crystal orientation desired and the surfaces were polished by employing standard metallographic techniques. The samples were then immersed in a solution of 1 to 3 g of KOH in 100 ml of water. This solution removes the damaged surface layers uniformly leaving a film on the surface of the sample. Etch pits are obtained by immersing the sample in an approximately 50-50 solution of 30 pct peroxide and concentrated acetic acid. The film formed during the KOH treatment turns deep red in color in the etching solution and flakes off the sample. The etching time required depends upon the pit size desired and

Jan 1, 1970

By Yosry A. Attia

One of the most significant advances in Mineral Processing in recent years, is the development of the selective flocculation technology. The technology is primarily aimed at recovering the mineral values from ultrafine ore suspensions. This is achieved by selectively aggregating the mineral particles in question to such size as to enable their effective separation from the suspension. Selective flocculation utilizes the differences in the physical-chemical properties of the various mineral components in the mixed suspension. It is based on the preferential ad- sorption of an organic flocculant on the particular solids to be flocculated, leaving the remainder of the particles in suspension. In order to understand the mechanics of this process, selective flocculation may be divided into four major sub processes; these being: ore slurry dispersion, in which all the particles are stably and uniformly distributed in the suspension with the individual particles being essentially separate; flocculant selective adsorption and floc formation; floc conditioning, which aims at obtaining flocs with desire properties for their subsequent separation and with minimum entrapment of dispersed particles; and floc separation from the suspension. These sub processes will be reviewed later in this article.

Jan 1, 1982

By Ryokichi Shimpo, Akio Fuwa

"The process-measurements of copper smelters in Japan were investigated for the summary of the latest technique and for the fundamental study of process control. The smelters investigated are those employing flash smelting furnace and P.S. converter, one reverberatory furnace and P.S. converter, and one continuous smelting converting furnace (M.I. process). Respective process is then considered, consisted of several reactors of different functions. The measurement methods were summarized in each reactor, including the measurement points. The methods of chemical analyses of the samples in each reactor were also investigated.IntroductionAn investigation on the process measurements, chemical analyses, and system control in copper smelters in Japan were carried out for understanding and summarizing the technique of the pyrometallurgical copper smelting operations. The typical seven processes in six copper smelters were investigated in the period from 1985 to 1987. The smelters investigated were Touyo Smelter of Sumitomo Metal Mining Co., Ltd., Kosaka Smelter of Dowa Mining Co., Ltd., Saganoseki Smelter of Nippon Mining Co., Ltd., Tamano Smelter of Hibi Kyodo Smelting Co., Ltd., Ashio Smelter of Furukawa Co., Ltd. and Naoshima Smelter of Mitsubishi Metal Co., Ltd. They include five flash smelting furnace and P.S. converter systems, one Mitsubishi continuous smelting and converting process (M.I. process), and one reverberatory furnace and P.S. converter system.The investigation was performed by making inquiries about the measurements, chemical analyses, system control, and their future prospects to the engineers in each smelter and by summarizing up in each item. The system control and future prospects were summarized in another paper titled ""Process Control Scheme of Copper Smelting Processes in Japan and Future View."

Jan 1, 1989

By C. E. Webber

The economical recovery of the valuable constituents from the effluent of gas-con-densate wells has developed into a problem of balancing the cost of recovery against the cost of compressing the residual gas back into the formation. A possible method of extracting the gasoline and distillate from the natural gas is by oil absorption at high pressures. In order to design and evaluate an absorption plant, fundamental data on the composition of the coexisting hydro- carbon vapor and liquid phases at various temperatures and pressures are essential. A review of the literature indicated that the necessary data for the design of such plants are lacking. The nearest approach to desired published data is that of Katz and Hackmuth,~ who experimentally deter-mined the composition of the coexisting vapor and liquid phases in a natural gas-crude oil system at pressures up to 3000 lb. per sq. in. and at temperatures from 40' to zoo°F. This paper presents the results of the experimental determination of the equilib-rium distribution of the hydrocarbons methane through hexane between natural gas and a typical absorber oil. The ranges of temperature and pressure chosen were from 33' to r8oUF. and from 100 to 5000 lb. per sq. inch. Materials The absorber oil was a typical naturally occurring, Straw-colored distillate that had previously been steam-distilled to an initial boiling point of 300 F. The physical and chemical properties, including the results of an Engler distillation, are presented in Table I. A large volume of this oil was obtained and it was used throughout the complete set of experiments. Table i.—Properties of the Absorption Oil Gravity .......................... . . 32.5' A.P.1. Molecular weight by benzene freezing- point depression.................. 183 Viscosity, poises; at 100°F........... 0.0a80 At 200°F...................... 0.0102 Composition, PeR Cent Aromatics........ 24.0 Naphthenes..... 36.7 unsaturates,Aromatics...... .I24.00.3 1 Parafins Naphthenes.....36.7 39.o EngLeR Distillation Per Cent /ncg. F. Per Cent Dez. P. Initial boilins rmint.. 300 I 60....... 523 5.................. 402 I 70....... 538 10.................. 421 180....... 557 20.................. 462 90....... 570 30.................. 480 1 95....... 623 40.................. 49 .................1 511 Residue, z .o per cent; loss, 0.3 per cent. See refrence I. The n-hexane was obtained from the Ohio Chemical and Manufacturing Co., Cleveland, Ohio. This liquid had a boiling range of from 149" to 152.6'F., with a density of 0.667 at 60°F. and a molecular weight of 85 by benzene freezing-point depression. The propane, isobutane, wbu-tane, isopentane and n-pentane were ob-ta,ined from the Philgas Department of the Phillips Petroleum Co. Certified analyses of these compounds showed their purity to be in excess of 99.5 per cent and they were riot further purified.

Jan 1, 1941

By B. Madelin

Over the last ten years, Minemet Recherche and Metaleurop have used an approach in order to investigate and improve the operation of its Smelting furnace and its lead blast furnaces. This approach gives importance- to three complementary means of investigation : - Probing campains in the industrial furnace (temperature and gas analysis profiles), - Chemical and physical modeling (coke combustion, sinter reduction modes, flows patterns, ?.) , - Staged mass and heat balances or kinetic model. This allows to define the limits of operation of each blast furnace and to predict the influence of operating parameters on the furnace performances. For the zinc Imperial smelting furnace, the probing results show the existence- of both an Isothermal reserve zone at 1015ºc and a chemical equilibrium between ZnO and gas which makes possible the use of a practical model for heat and material balances. In particular, very good prediction on the influences of operating parameters can be made. On the contrary, for lead blast furnaces, the probing results show that the thermal and chemical equilibria are not reached. Consequently, classical models for staged heat and mass balances are not sufficient. The use of the other means allows then to characterize the specific influences of operating parameters on the thermal instabilities of these furnaces and their allowed limits.

Jan 1, 1990

By L. Sun

In this work, strontium doped lanthanum ferrite (LSF) and their composite cathodes were fabricated by screen printing on yttria-stabilized zirconia (YSZ) electrolytes. Their electrochemical properties were evaluated by using electrochemical impedance spectroscopy and steady-state polarization methods. All the cathodes were screened by comparing their total polarization resistances before and after activation processes at different temperatures. The improved LSF composite cathodes were also screen-printed on YSZ/NiO half cells to fabricate solid oxide fuel cells (SOFCs), which have reached the output power densities of 170 mW/cm2 at 650 °C, 230 mW/cm2 at 700 °C, 304 mW/cm2 at 750 °C and 388 mW/cm2 at 800 °C.

Jan 1, 2005

By Burton H. Boyum

Greater depth of exploration drill holes and increasing cost of drilling have been principal factors in reviving interest on the Mar-quette Iron Range in controlled directional drill-hole deflection. This deflection is obtained by the application of the Hall-Row wedging technique. Modifications were made in the technique and equipment in the effort to simplify and strengthen the procedure. The practice is similar in many respects to the oil well type of deflection with a whipstock. Introduction The deflection of diamond drill holes by wedging was a widespread practice in Canada, South Africa and the Lake Superior District as early as 1907 to 1920. Several basic schemes were used, with local variations.' The deflecting wedge assembly was the idea of Mr. Welldon and Mr. Payne-Gallwey operating under the supervision of Mr. William Gallagher of Johannesburg, South Africa. All schemes employed some means of plugging the old hole. A footpiece of various styles was placed in the hole on the plug. In some methods, the orientation of this piece was determined before placing the deflecting wedge. Some techniques permitted continuing the hole the same size after wedging, while others necessitated a size reduction. Interest in wedging diamond drill holes in the Lake Superior District waned after 1920. The Hall-Row patented system for deflecting holes was developed in Canada about 1918.2 Interest centers on the wedging process for the following applications: 1. Maintaining a given course and inclination of the drill hole. 2. By passing an obstruction in a drill hole. 3. Resampling an ore body. 4. Exploring an area overlain by surface conditions not favorable to drilling. During the period of 1913 to 1920, The Cleveland-Cliffs Iron Co. used the wedging technique under a variety of conditions. In general, the practice was not applicable again until 1946. Meanwhile the Hall-Row system of drill-hole deflection survived years of application as the best technique available. In the intervening years, our depth of exploration has increased as well as the overall cost of drilling. As exploration becomes deeper, there is the possible economy of cutting the ore body at a moderate distance from the parent hole without redrilling from surface. Thus a branch hole started near the mid-point of a deep hole can reach the ore horizon at a considerable offset from the parent hole. This permits a greater interval between surface drill holes as drilling becomes deeper. Our interest revived in the subject and a wedging program was initiated. General Description Results The maximum theoretical angular deflection possible, based on the deflecting

Jan 1, 1949

By Irving Hartmann

In recent years various modifications in the methods of blasting have been tried as a means of increasing the production of cod and of reducing mining costs. Following an investigation by the Bureau or Mines, authorization was granted to increase the charger limit for permissible explosives par shot hole from 1.5 to 3 pounds under contain conditions; this greatly facilitates the blasting of coal in some cool fields the practice has gradually evolved of simultaneously charging several shot holes in a face and then firing the charges singly without inspecting for gas after each blast. This practice is disapproved by the Bureau of Mines. In other coal mines the explosive chews in several adjacent shot holes are fired simultaneously. This form of shooting is claimed to increase the rate of production, generate smaller volumes of noxious gases, promote the health and safety of workers by eliminating the need of inspection of the face after each charge is fired, produce less float dust, and require less explosive than single shooting. However, simultaneous blasting may have a more harmful effect on the immediate roof strata; in some instances it leads to wedging of the broken coal, thereby making the coal more difficult to load out; it makes misfired shots more difficult to detect and possibly increases the chances of misfires. This lacy be duo to variations in the characteristics of detonators, because of more stringent requirements for adequate firing current, to the need for better electrical connections in the shot-firing circuit, and partly to the inadequacy of present permissible multiple blasting devices.

Jan 1, 1952