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Research by the National Institute for Occupational Safety and Health (NIOSH) on multiple-seam mining has resulted in two new ground control products. Information Circular (IC) 9495 In some U.S. coalfields, particularly in central Appalachia and the West, most mines are operating above and/or beneath previously mined seams. The effects of multiple-seam interactions can include roof falls, rib spalling, and floor heave. These can seriously threaten the safety of miners and disrupt mining operations. Information Circular (IC) 9495 is a proceedings document containing a variety of papers that summarize recent knowledge about multiple-seam mining. A NIOSH study that analyzed case histories collected from 44 U.S. coal mines is described in detail. The study confirmed that overmining is much more difficult than undermining, and isolated remnant pillars cause more problems than gob-solid boundaries. The study's results were the basis for the Analysis of Multiple-Seam Stability (AMSS) software package. The proceedings also contain two papers describing the LaModel family of software. The original three-dimensional version of LaModel is essential for detailed analyses of complex multiple-seam scenarios. LaM2D implements a simplified, two-dimensional model suitable for quick approximations of the multiple-seam stresses and strains. Three papers in the proceedings focus on case histories. One describes the extensive multiple-seam experience at the Harris No. 1 Mine in West Virginia, a second contains examples of "extreme" multiple-seam mining from the central Appalachian coalfields, and a third describes interactions with regard to longwall mine experiences in Pennsylvania, West Virginia, and Utah. The final paper reports on a numerical modeling study that provided some insight into the mechanics of multiple-seam mining. [ ] AMSS Software Package NIOSH has developed a simple, user-friendly computer program called Analysis of Multiple-Seam Stability (AMSS). AMSS can help mine planners to evaluate each potential multiple-seam interaction and take steps to reduce the risk of ground control failure. AMSS begins by evaluating the pillar design. It first calculates the single-seam pillar stability factor (SF)

Jan 11, 2007

By E. Roman, M. Brissette

"For its end of life, Kemess Mine processed its difficult-to-treat hypogene ore from the east pit, which is a lower grade copper and higher pyrite content gold ore. Metallurgical testwork showed that improvement was possible with finer grinding. In July 2010, small grinding media were introduced into the regrind mill resulting to a nearly 50% decrease of the power draw with a finer grind, an increase of 1.1% in the final copper grade, an increase of 1.2% in copper and 2.9% in gold recoveries at the cleaners. The overall recoveries of copper and gold increased by 0.6% and 1.3% respectively.INTRODUCTION Kemess Mine was located at 430 km North West of Prince George in North Central British Colombia. Its production started in May 1998 by Royal Oak Mines and was acquired by Northgate Exploration in 2000. Kemess reached its end of life production with its last of production on March 9th, 2011. The concentrator nominal capacity was 56,000 TPD consisting of a primary gyratory crusher feeding two identical conventional SAB circuits totalizing 35,840 kW available for grinding. Rougher flotation consists of four parallel rows of eight 130 m³ tank cells to produce a concentrate of 2% Cu and 6 gr/t Au which was pumped to a 5 m x 10.8 m regrind ball mill. The regrind installed power was 4,480 kW to generate a final grind of 80% passing 40 microns. This product fed the two stage cleaner flotation circuit, first stage being two parallel rows conventional 17 m³ Denver cells and second stage, two 3.3 m x 11.0 m flotation columns in series, designed and constructed by Kemess, to produce a 22% copper concentrate grade. The cleaner flotation middlings were returned back to the regrind mill (Froehling, Mohns, Roman & Grady, 2005; Froehling, Mohns, Rajwani & Fullam, 2007). The large copper-gold porphyry deposit was composed of 15% of oxidized supergene and leach cap ore and 85% of hypogene ore having three major alteration zones, mainly characterized by their sulphur/sulphide content. Chalcopyrite is the main copper mineral species with minor bornite. Gold was mainly present as free gold or electrum. The first alteration zone consisted of a phyllic alteration characterized by moderate and intense sericite alteration which had the highest mill throughput and twice the mine grade when in contact with the supergene horizon. The second zone consisted of a potassic alteration characterized by more competent groundmass and moderate to intense quartz stockwork which had a slightly lower mill throughput. Finally, a third alteration found beneath and on the east side of the deposit having almost no quartz stockwork and hardened groundmass, sulphide content is two to four times more. This zone had the lower mill throughput with significant drop in the mine average gold and copper grade. Through its mine life, the average life of mine copper head grade was 0.21% Cu and 0.64 gr/t Au. Head grades began to decrease from 2008 to be substantially lower in 2011 as shown in Table 1."

Jan 1, 2012

By F. A. Penning

Improved skips, with lightweight cylindrical bodies, have made a significant contribution to advancing mine hoisting technology. New concept skips of aluminum bodies with rubber lining; fiberglas bodies with polyurethane liners have been designed and fabricated for field testing at an operating mine. New design, adjustable guide rollers have shown improved ride characteristics with noticeably less wear. Major reductions have been made in stress levels and stress concentrations. Field experience has shown the practicality of the approach. Guide alignment has been measured using the Guide Alignment Measuring System (GAMS). Analysis has been applied to interpret the data. Field measurements in an operating shaft and a test tower have shown the agreement in data from GAMS and plumb wires. Reproducibility has been demonstrated. The data are useful to realign shafts, to use as s maintenance tool, and to evaluate the maximum safe hoisting speeds. The surveys are made at several hundred feet per minute and the system is self-contained. Dynamics of skip-guide interaction has been analyzed using the computer program SKIP II. The effects of speed, weight, type of guides, kind of misalignment have been studied. Resonance has been demonstrated and factors that eliminate resonance have been identified. Data from the GAMS surveys are applicable to the SKIP II program. Interaction between the hoist rope and the mine conveyance has also been studied. Computer programs and closed-form solutions are presented. Economic impact of lightweight skips is presented for an existing mine and for a new mine. Reduction in rope size has a profound effect when using a lightweight skip for the same capacity. Increased productivity can be realized by keeping maximum rope pull the same while increasing skip capacity. Examples and charts project the significant savings in capital expenditure for new installations.

Jan 1, 1985

Scenario reduction is designed for selecting a representative subset of geostatistical simulations out of a much larger set. Three steps are involved: measuring the dissimilarity between two simulations; finding a metric to measure the distance between any subset of k simulations and the full set of N simulations; and finding an efficient algorithm for selecting the subset that minimizes the metric. This paper focuses on the third question. We show that genetic algorithms are an efficient way of approaching the minimum when the population of subsets to be sampled is large. Two case studies based on the Walker Lake data-set are presented: firstly choosing k=4 simulations out of a total of 100, and secondly choosing 20 out of the same 100 simulations. In the first case it was possible to compute all possible combinations exhaustively and hence to demonstrate that the algorithm converges to the true minimum. This was not possible in the second case. Instead we demonstrate that it outperforms the random draw algorithm used in earlier work. A procedure for tracking individual selections during the iterative procedure was developed. This allows us to measure the evolution in the percentage of progeny resulting from crossing-over and from mutation that survived in the next generation. It gives valuable insight into how to choose the parameter values in the algorithm. Another key finding is that there is a trade-off between the number of individuals per generation and the number of generations required for the algorithm to converge.

Jan 1, 2014

By Paul G. Swanson

This investigation was conducted to identify the principle causes of spoil instability problems in the Eastern Coal Province. The study was also conducted to develop a matrix to predict the strength and groundwater parameters necessary to conduct stability analyses on a proposed reclamation scheme. Suggestive methods to reduce spoil instability potential are also included. Numerous physical property, strength, compressibility, chemical and mineralogical tests were conducted on mine spoil samples obtained from 11 different surface mine sites. Site characteristics that influence the position of the post reclamation groundwater table were identified. Distinct regions within the Eastern Coal Province with high incidences of surface mine slides or high landslide susceptibility were identified. The application of the predictive matrices developed in this study is for surface mine sites mined and reclaimed in general accordance with the Surface Mine Reclamation Control Act of 1977. A review of current mining practices and the relative effect on spoil stability is included.

Jan 1, 1983

By F. Ikumapayi

Hydrogen peroxide production was measured during the grinding of a complex sulfide ore, and its oxidizing effect on solid surfaces was investigated using Fourier transform infrared spectroscopy (FTIR) with diffuse reflectance attachment measurement. In turn, an attempt was made to correlate the formation of hydrogen peroxide, surface oxidation and sphalerite flotation. Additionally, in order to predict and minimize detrimental production problems due to the recycling of process water in sulfide ore processing, the effects of major components of calcium and sulfate species present in recycled process water and the effect of temperature on sphalerite flotation were investigated through bench-scale flotation tests using complex sulfide ores. The significance of process water species in flotation was studied using tap water, process water and simulated water containing calcium and sulfate ions. Formation of hydrogen peroxide was revealed during the grinding of the complex sulfide ore, and its formation was counteracted by diethylenetriamine (DETA). The FTIR spectrum of the pulp solid fraction showed varying degrees of oxidized surface species, which are related to the concentration of H2O2 analyzed in pulp liquid. Bench-scale flotation using two different complex sulfide ores showed that sphalerite recovery is better in process water than in tap water. Flotation results also indicated a varied recovery of sphalerite at different temperatures in either tap water or process water.

By Wesley T. Holmes

This report describes the second phase of an investigation aimed at obtaining a wider knowledge of the problems involved in smelting titaniferous magnetites. Liquidus temperature measurements were made on selected synthetic slag compositions in the Ti02 -A1203 -FeO-Si02 -CaO-MgO system. Both the hot-stage microscope and the strip furnace (melting-holding-quenching technique) were used during test procedure to determine the effects of CaO, MgO, and SiO2 on the liquidus temperature of slags. The liquidus temperatures of slags studied ranged from 1,241° to 1,900° C. The lowest liquidus temperature for each Ti02 plus A1203 plus FeO weight-percent generally occurred when the difference between CaO plus MgO and Si02 was less than 12 weight-percent. In this investigation substitution of either CaO or MgO for SiO2 and MgO for CaO raised the liquidus temperature of more than 50 percent of the reported base slags when Ti02, A1203, and FeO contents were held constant. The results of this investigation may serve as guidelines for determining flux requirements in smelting a wide variety of titaniferous magnetite concentrates or ores.

Jan 1, 1968

By D. R. McConnell

The seafloor in the US Pacific OCS and EEZ is enriched to varying degrees in critical and economically important minerals such as nickel, manganese, cobalt, copper, zinc, REY (rare earth elements plus yttrium), titanium, vanadium, antimony, gold, and silver. These mineral deposits take the form of polymetallic nodules on the seabed, cobalt rich ferromanganese crusts on seamounts and ridges swept clean of sediment accumulation, and seafloor massive sulfides formed by hydrothermal systems at geologic plate spreading centers and volcanic margins. Each of these mineral deposits form on or near the deep ocean seafloor where water depths are typically 4000 m to 5500 m and on the seamounts and volcanic arcs that rise from these depths. Commercial interest in deep sea mineral deposits and the potential for collecting or mining them began in earnest in the 1970s but has been heightened in the last 20 years as the international framework for developing these minerals in International Waters has matured that has coincided with forecasted rapid rising demand for minerals to supply energy and manufacturing needs for the green economy. Compilation reports published by academia, government, and private companies are reviewed to assemble data and assess the prospects for deep sea marine minerals in the US Pacific OCS and EEZ. Key compilations were made by the Circum-Pacific Council and USGS in the 1980s and 1990s. These, together with recent (2023) efforts by USGS to compile geochemical data from USGS affiliated marine research sampling cruises from the 1980s and 1990s, historical data maintained by NOAA National Centers for Environmental Information (NCEI), and recent publicly disclosed results from ISA contractors are used to inform the known occurrence and prospectivity for polymetallic nodules, cobalt-rich ferromanganese crusts, and seafloor massive sulfides in the US Pacific OCS and EEZ.

Feb 22, 2026

By Stefan K. Schwank

The paper describes the two foundation techniques - mini piles and postgrouted bored piles. The mini pile system is presented with its design and installation parameters, especially the drilling technique. Two case histories demonstrate the application under extremely limited space and traffic conditions and the required modifications of the equipment. After the description of the postgrouted bored piles and its grouting technique, the paper gives a comparison of postgrouted piles and standard piles on a large basic test in Germany. The Brooklyn Queen's Expressway, N.Y., case history shows the application of this technique after redesign of the original proposal. 1. General Increasing requirements to improve existing foundations to carry additional loads and to increase the bearing capacity of bored piles leads to two new piling techniques: the mini-pile and the post grouted bored pile.

Jan 1, 1991

The U.S. Code of Federal Regulations (Title 30) requires that a methane monitor be placed on every mining machine to continuously observe and record methane levels at the face. The monitor must provide a warning whenever methane levels are 1.0 percent or higher. An effective monitoring system will indicate a methane concentration of 1.0 percent on the mining machine before methane levels at the mining face reach 5.0 percent. Where the methane monitor is located on the mining machine is one of the most important factors that determines how effectively face methane levels can be predicted. Any change in the sampling location will result in a change in measured methane concentration. To protect the methanometer, it is usually located on the cutting boom at least 1 to 1.8 m (3 to 6 ft) outby the front cutting bits. A face ventilation system using blowing tubing was simulated in a full-scale test facility. Methane released from the face area was monitored at multiple locations on a model mining machine as well as locations near the face. Based on the relationship between concentrations measured on the machine and at the face, criteria were developed for selecting the best machine locations for monitoring methane. Recommendations are given for revising methane action levels for alternative sampling locations.

Records over the past ten years indicate that there is potential for serious multiple accidents due to engulfing associated with rockpasses. Significant attention is not usually given to the design of rockpasses, with the implication that mistakes leading to poor performance of the passes are often repeated. This paper outlines general guidelines for the design, support, operation and rehabilitation of rockpasses based on information obtained from the limited amount of literature on the subject.

Jan 1, 2005

By R. A. Cattell

The peacetime activities of the Bureau's petroleum and natural-gas program have been reoriented to serve the needs of a national-defense program. When the United Nations sent troops to Korea after the North Korean Army crossed the 38th parallel in the latter part of June 1950, the Bureau's coordinated national program on petroleum and natural gas, with each major project forming an essential member of its framework, was carefully reviewed by those in charge of the work. As a matter of fact, the era of normalcy in which the petroleum and natural-gas research of the Bureau of Mines prospered during the fiscal year 19502/ was no sedative to the need for alertness on a national-defense front. The program, although conducted along peacetime lines in general, was scanned critically and repeatedly during that period to see where - if the need should arise -the emphasis could be shifted from peace to defense or war. Judging from the experience of two wars, it would not be long before the Bureau would be asked to use its trained technical personnel in applying techniques already learned in peacetime research to the requirements of munition and fuel needs of national defense. Near the end of January 1951, petroleum and natural-gas engineers of the Bureau of Mines began a comprehensive study of reservoir conditions in the Canyon Reef fields of Scurry, Borden, and Kent Counties, Tex. This work was preceded by published analyses of crude oils from Scurry County as early as April 1950. Well-informed persons in industry have estimated that these fields hold reserves that will yield 3 to 6 billion barrels of stock-tank oil. Although generally accepted good operating practices have been followed, engineering tests have shown that the natural energy, except in some favorable parts of the reservoir, will not be adequate for obtaining a high percentage of recovery. Correct information regarding the extent and availability of this vast reservoir of hydrocarbons is therefore of great concern to the Petroleum Administration for Defense in carrying out its responsibilities under the Defense Production Act.

Jan 1, 1952

By H. E. Biber

DURING the production of tin plate a thin layer of FeSn2, is formed at the interface between the steel sheet and the protective tin coating. Because excessive amounts of this alloy layer are undesirable, the kinetics of its formation is a subject of interest in the tin-plate industry. A recent study of this subject at our laboratory uncovered a relationship which should be of general interest to anyone studying kinetics of reactions in metallic systems. It had been previously concluded that, at any given temperature in the range 175" to 330°C, the Fe-Sn alloy layer would have a parabolic growth rate.1,2 However, our studies showed that this rule apparently holds only when the tin plate is heated very slowly to the "reaction" temperature; when the tin plate is rapidly heated, considerably different growth rates occur. An example of this effect of heating rate on growth behavior is contained in the accompanying results of alloy-layer growth measurements at 240°C in oil baths stirred at 10,500, 1800, and 0 rpm. The heating curves for these three conditions are given in Fig. 1, and the growth data are presented in Fig. 2. With the rapid heating rate, provided by the stirring at 10,500 rpm, the alloy layer had three distinct stages of growth. In the initial stage, which persisted well beyond the time required to heat the tin plate to bath temperature, the alloy layer formed very rapidly. The growth followed a rate law of the form w = ktn where n > 1. This initial stage was followed by a growth-retardation stage of about 50-sec duration in which little additional alloy was formed. In the third stage the growth again followed a rate law of the form w = ktn, but here « =0.3. With the intermediate heating rate provided by stirring at 1800 rpm, the three-stage nature was less pronounced and the slope of the third stage increased (i.e., n > 0.3). With the slow heating rate provided by the unstirred oil bath, the alloy layer grew in two stages. The initial rapid-growth stage persisted only until the specimen was heated to bath temperature, no growth retardation was observed, and the slope of the main portion of the plotted data was greater than in the stirred baths, having a value of almost 0.5. Similar results were obtained for other bath temperatures in the range 200" to 300°C. This effect of heating rate on growth behavior may be due to changes in the rate of nucleation of FeSn, crystallites. The iron and tin are in contact from the onset of heating. Thus the initial formation of FeSn, occurs not at the "reaction" temperature but rather while the tin plate is being heated to that temperature. Because nucleation is in general temperature-dependent, different heating rates could cause different over-all nucleation rates, which in turn could cause different growth behaviors. A more detailed discussion of the growth of Fe-Sn alloy layer and the effect of heating rate will be published shortly.

Jan 1, 1965

By G. Zhu

The straight Y-shaped silica nanorods have been synthesized on Si wafer by thermal chemical evaporation of mixed powders of silica and graphite at 1300_ and condensation on Si substrate without assistance of any catalyst. The synthesized samples were characterized by means of scanning electron microscopy, transmission electron microscopy. The results suggested that the straight Y-shaped silica nanorods have uniform diameter about 50-200nm and neat smooth surface. The growth of such silica nanorods may be a result of the fluctuation of external conditions and internal structure faults causing a change in the growth direction of silica nanorods developed.

May 1, 2008

Yallourn brown coal and its characteristics have been the subject of innumerable papers and discussions. The Lurgi process adopted for the production of Towns gas by the gasification of brown coal has been described frequently in literature.The application of the Lurgi process for the gasification of Yallourn briquettes has naturally lead to some unexpected problems. Rather than attempt to review the whole field of experience gained in the first two years of operation of the gasification plant at Morwell, this paper attempts to describe two problems encountered, peculiar to the fuel used, and the steps taken in overcoming them.THE PROCESS AND PLANTTo clarify the conditions surrounding the problems, it is necessary to briefly describe the gasification and cooling processes and plant.Brown coal briquettes are gasified in a pressure generator, using a mixture of steam and oxygen as a gasifying medium. Crude gas produced in the generator is washed and cooled in the waste heat boiler and coolers. Figure 1 shows an arrangement of the generator and coolers. The gasifying medium enters the generator through a hollow shaft in the base. This shaft drives the grate, which has three purposes: (a) to distribute the gasifying medium into the fuel bed; (b) to extract the ash from the fuel bed; (c) to support the fuel bed.Briquettes enter the top of the generator through the coal lock chamber and the fuel bed is maintained at a reasonably...

Jan 1, 1960

By Shail J. Butani

In 1986 the Bureau of Mines conducted a probability sample survey, Mining Industry Population Survey, to measure such employee characteristics as occupation; principal equipment operated; work location at the mine; present job, present company, and total mining experience; job-related training during the last 2 years; age; sex; race; and education. The population estimates are necessary to properly analyze the Mine Safety and Health Administration (MSWA) injury (includes illness and fatality data) statistics; that is, to compare and contrast injury rates for various subpopulations in order to identify those groups that are exhibiting higher than average injury rates. This report uses the survey's results to characterize the U.S. metallic mining workforce from March through September 1986. Similar reports have been published for the stone, sand and gravel, and nonmetallic mining industries, as well as for the entire metal and nonmetal mining (includes metallic, stone, sand and gravel, and nonmetallic industries) sector and the coal mining sector.

Jan 1, 1988

By Yoginder P. Chugh

The characteristics of weak floor strata associated with actively mined coal seams in Illinois are very important from ground stability point of view and, in many cases, are the governing factors in determining the size of pillars and mine openings. Laboratory and field getotechnical characterization studies of weak floor strata were conducted at six mines during the period 1985-1988. Correlation analysis among engineering index properties, and laboratory, and field determined strength-deformation properties were conducted to identify simple tests which can be used to estimate ultimate bearing capacity and deformation properties of immediate floor strata. It was concluded that the ultimate bearing capacity (UBC) and strength- deformation properties of the weak floor strata can be estimated from simple tests such as, natural moisture content, atterberg limits, and axial swelling strain. Indirect tensile strength was found to be a better estimator of UBC than unconfined compressive strength.

Jan 1, 1989

To improve communications between mine workings and surface locations during emergency situations and for administrative purposes. The Approach: Development of a device for interconnecting phone systems which permits two-way communication between a public telephone and a mine pagerphone by authorized personnel. How It Works: The system, developed by personnel at the Bureau's Pittsburgh (Pa.) Mining and Safety Research Center, makes connections between the public phone line and mine pagerphone line. As shown in Fig. 1., incoming calls are sensed by the ring detector (4) and the system "answers" the call electronically. To reach the pagerphone system, the caller inserts an audible tone of fixed frequency through the microphone of his telephone. This tone is produced by a miniature, pocket-carried tone generator and is detected by a tone recognition circuit (5). When this hap-pens, relay, switching, and logic circuitry (6) closes the connections between the two phone systems. Simultaneously, a page activator (9) places a DC paging voltage on the mine phone line.

Jan 1, 1974

Vein swarms in metamorphic terranes such as the Otago Schist Belt, New Zealand provide evidence of past hydrothermal flow systems leading to fault initiation and reactivation. A major episode of hydrofracturing and fluid redistribution occurred during early Cretaceous exhumation of the schist belt. As a result, presently exposed lower greenschist facies greyschists in NW Otago are pervaded by abundant quartz-filled hydraulic extension fractures with associated normal faults hosting quartz¦scheelite¦gold mineralisation. Once the effects of Cenozoic folding have been removed, a regional subhorizontal schist foliation contains an aligned array of subvertical hydrofractures striking NNW, striking parallel to a set of low-slip conjugate normal faults; the array extends over an area >1500 km2 and over a depth interval >5 km. The hydrofracture array comprises a mesh of interlinked extensional-shear and pure extension veins. These veins show mutually cross-cutting relations. Extensional hydrofracturing apparently preceded the development of major throughgoing normal faults. Low-displacement normal faults are infilled with laminated quartz (¦ scheelite) veins (

Jan 1, 2002

By C. Crussard, R. Tamhankar

It is the policy of The Metallurgical Society to provide, in the TRANSACTIONS OF THE METALLURGICAL SOCIETY OF AIME, a prompt and accurate medium for publication of reports of significant new research in both the scientific and engineering aspects of metallurgy. Papers submitted to the Society are judged by competent reviewers accord-ing to established criteria for technical merit, accuracy, originality, and presentation. STAFF: Editor, Gerhurd Derge Carnegie Institute of Technology Schenley Park Pittsburgh 13, Pa. Editorial Assistant, M. A. Redmerski Staff Coordinator, James J. Burke THE METALLURGICAL SOCIETY: W. R. Hibbard, Jr., President; J. C. Kinnear, Jr., Past-President; John Chiprnan, Vice President; T. D. Jones, Treasurer; R. W. Shearman, Secretary. PUBLICATIONS COMMITTEE OF THE METALLURGICAL SOCIETY: A. W. Thornton, Chairman; Dennis Carney, John Chip-man, J. C. Fulton, J. H. Hollomon, H. H. Kellogg, A. E. Lee, R. Maddin, J. D. Sullivan, and D. Swan. Review and selection of manuscripts is under the supervision of the following Publications Committees: Extractive Metallurgy Division: T. B. King, Chairman; S. J. Dickenson, R. P. Hermsdorf, R. Schuhmann, Jr., and P. T. Stroup. Institute of Metals Division: Robert Maddin, Chairman, F. Lincoln Vogel, Jr., Vice-chairman, W. A. Backofen, R. W. Balluffi, J. H. Bechtold, M. B. Bever, R. S. Busk, C. G. Goetzel, Paul Gordon, C. D. Graham, .Jr., Robert F. Hehemonn, R. I. Jaffee, F. E. Jaumot, Jr., Irving R. Kramer, A. J. Lena, Harold Margolin, C. J. McHorgue, Russell A. Meussner, J. B. Newkirk, H. W. Paxton, G. E. Pellissier, I. S. Servi, Alan U. Seybolt, A. J. Shaler, and Jack Washburn. Iron and Steel Division: J. C. Fulton, Chairman; T. B. King, F. C. Langenberg, W. 0. Philbrook, and T. 0. Winkler. Published bimonthly by the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc., 29 West 39th Street, New York 18, N. Y. Telephone: PEnnsylvania 6-9220. Subscription $20 per year for non-AIME members in United States and North, South, and Central America; $25, foreign; $5 for AIME members. Single copies, $4.00, single copies foreign, $5.00. The AIME is not responsible for any statement made or opinion expressed in its publications . . . Copyright 1958 by the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. . . . Registered cable address, AIME New York ... Indexed in Engineering Index, Industrial Arts Index, and Chemical Abstracts... Second class postage paid at New Yark, N. Y., and Ann Arbor, Mich. Volume 212, Number 6.

Jan 1, 1959