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The following is an incomplete list of members and guests who called at Institute headquarters during the period Apr. 10, 1918 to May 10, 1915. Robert H. Chapman, Washington, D. C. Francis Nicholson, Charlotte Court House, G. A. Collins, Seattle, Wash. Va. W. N. Cummings, Orange, Cal. F. S. Platt, Australian Imperial Force. W. A. Deane, Summitville, N. Y. H. Rabling, Melbourne, Australia. H. W. Edmondson, Camp Lee, Va. James C. Ray, Palo Alto, Cal. H. F. E. Gamm, Rutherford, N. J. Jasper T. Robertson, Chicago, Ill. A. L. Gholz, Minneapolis, Minn. John A. Root, Kings Mills, Ohio. H. H. Hodgkinson, Dover, N. J. Robert H. Seip, Franklin, N. J. Norman L. Jenks, Marmato, Colombia, Trevor B. Simon, Morristown, N. J. South America. H. N. Stronck, Chicago, 111. Paul S. King, Wilmington, Del. Benjamin F. Tillson, Franklin, N. J. Ray G. Knickerbocker, Rolla, Mo. J. R. Underwood, Granby, Mo. Carl A. Lewis, Habana. Thor Warner, Phoenix, Ariz. Robert S. Lewis, Salt Lake City, Utah. G. B. Waterhouse, Buffalo, N. Y. Edmund Newton, Minneapolis, Minn. W. M. Weigel, Renfrew,. Ont., Canada. Alexander Nicholas, Australian Imperial Chas. F. Willis, Tucson, Ariz. Force. Ralph Arnold is devoting a part of his time to work as a member of the Board of Tax Reviewers in connection with the administration of the War Revenue Act.

Jan 6, 1918

By Shigehito Deki

"A new wet process has been developed for the synthesis of various kinds of oxide thin films on various kinds of substrates, even which have complex surface morphology, from aqueous solution. The process was named as the LPD, Liquid Phase Deposition, method, which has some advantages over the conventional dry processes. This process can be applied to an on-site synthesis of advanced materials in the thin film technology. In this paper, some current topics on the synthesis of the composite thin oxide films by the LPD method, are presented.IntroductionGenerally, metal oxide thin films have been made by different preparative processes such as r.f. sputtering, chemical vapor depositon, CVD, laser ablation and sol-gel method, etc [1-3]. Each method has it own advantages and disadvantage. In some cases, the process is not suitable for the preparation of thin film on substrate with large surface area or complex surface morphology, and makes the deposition apparatus complicated and expenisve. By using Liquid Phase Deposition, LPD, method which overcomes some of those problems, metal oxide or hydroxide thin film can be formed on the substrate with large surface area and complex surface morphology, which are immersed into the aqueous solution only at ambient temperature and under atmosphere without any special equipments and high energy. And also, multicomponent oxide thin films can be formed readily by mixing solutions containing the objective metal ions, because it is performed in the aqueous solution which is typically a homogeneous mixing system. This process utilizes ligand-exchange, hydrolysis, equlibrium reaction of metal-fluoro complex species, MF x (x-2n>-, and F consumptive reaction. In the aqueous solution, MFx<x-2n>-is hydrolyzed with water to release F ions by a ligand exchange equilibrium reaction as following;"

Jan 1, 2000

By Donald M. Benjamin

Florida&apos;s electrical needs are served by 58 utilities of practically every type: six investor-owned, 34 municipal, 17 cooperative, and one federally-owned. They range in size from a small municipal system with a, 2 MW annual peak demand CD a large investor-owned utility serving about one-half of the state with an annual peak demand of 8,600 MW. (1),(2) These utilities are interconnected at several voltage levels with 230kV serving as the pre-dominant voltage for the bulk power transmission system. About 275 miles of 500kV circuits are found within two systems, but no tie-lines yet exist at this voltage. Due to Peninsular Florida&apos;s (that portion of the state east of the Apalachacola River) geographic location and shape, it cannot, at present, depend upon its interties with the remainder of the nation to completely support the sudden loss of the state&apos;s largest generator. Therefore, the utilities maintain a total amount of spinning reserve to cover for this single contingency outage at all times. Most of the state&apos;s electric utilities belong to the Florida Electric Power Coordinating Group (FCG) which, through its standing committees, coordinates the planning and operation of the member systems. Though a formal, centrally dispatched pool does not exist in the state, generating utilities which belong to the FCG&apos;s Operating Committee subscribe to an energy broker operation to maximize the savings that can accrue from economy interchange. Studies are underway, with participation from the staff of the Florida Public Service Commission, that are investigating both central planning and dispatch of the peninsula&apos;s electric utilities. Florida&apos;s electric load is mainly residential. During: 1976, 48.8% of all electrical energy use was by residential customers; 31.8%, commercial; 16.2%, industrial; and 3.2% for all other. By comparison, 32.7% of the United States&apos; load was residential, followed by 40.5% industrial, 23.0% commercial, and 3.8% other.

Jan 1, 1978

By Frederick W. Lee

List of contributing editors of Geophysical Abstracts:

Sep 1, 1932

By George A. Laird

I. INTRODUCTION. THIS old and once famous district played, through its enormous production of silver and gold, an important part in the history of the State of San Luis Potosi. According to a pamphlet prepared under the direction of the Governor of the State, Sr. Don Blas Escontria, and presented to the visiting members of the Institute during the Mexican meeting of 1901, this district is situated 20 km. east of the city of San Luis Potosi, in a range of mountains of moderate height, extending 135 km. N. and S., and 16 km. E. and W.; and the mineralized area hitherto developed is about 600,000 sq. m. The history of the district,. as given by the record dated 1778, and formerly kept in the San Francisco convent, says that it was discovered in 1575 by Sr. Don Pedro Irarte, and adds that the city of San Luis Rey de Francisco del Potosi received its name (in allusion to the famous Potosi mines in Bolivia) by reason of the remarkable productiveness of its gold- and silver-mines in the first period of their exploration, during which they paid to the Crown, as " quintos " (the fifth part of the product), $97,000,000, as appears from the accounts of the royal treasury. The amount of the quientos paid during the " bonanza period " of 80 years was $72,000,000. The larger sum first mentioned probably represents a longer series of years. But either will suffice to indicate the great wealth of the mines. In 1663, the decadence of the industry began with the caving¬ in of several mines, concerning which the record of 1778, al¬ready cited, says, in substance, that on Good Friday one of the owners in the enterprise, in view of the unfavorable prospect of a lawsuit in which he was engaged, set fire to the timbers supporting the underground galleries and workings of the San

Jan 1, 1905

By D. W. Bacon

Plant process optimization programs are often costly, both in technical effort and loss of production. Evolutionary Operation or "EVOP" is a mode of plant operation consisting of controlled cyclical changes in process conditions by which information is provided concerning potential process improvements while both volume and quality uniformity in production are maintained. Its conceptual simplicity and low cost of utilization have led to successful adoption in a variety of industrial manufacturing operations. This paper is an expository account of basic EVOP theory, the problems encountered and the organization required in applying it to a processing plant. Illustrations are provided which indicate the payoff that can result.

Jan 1, 1967

By A. Goulsbra, S. McAllister, R. Dunne

Since 1992, a tailings gravity re-treatment plant has been in operation at the New Celebration Gold Mine to recover aurifer­ous pyrite (Martins, Dunne and Gelfi 1991; Martins, Dunne and Delahey 1993). The gravity pyrite concentrate is ground in a Tower mill to liberate gold (average particle size around 25µm) prior to cyanide leaching. Although the re-treatment plant has met the predicted gold recovery, based on original laborat01y testwork, there is still room for improved gold recovery. This requires enhanced pyrite recovery, especially in the finer size ranges. The application of centrifugal gravity separators would seem to be an ideal means to achieve this criterion. In particular, the Falcon continuous centrifugal separator (Series C machines) would appear to be ideal for this particular duty. A testwork program to evaluate the application of the contin­uous Falcon to recover pyrite from New Celebration ores was unde1iaken over a six month period during the later part of 1997. The work involved laboratory batch testwork, followed by con­tinuous testing of the Falcon Cl0 (2tph to 3tph) and Falcon C40 (l00tph) units. A summary of the results from this evaluation program are provided in this paper.

Jan 1, 1998

By James Westfield

Uranium activity has introduced a comparatively new hazard to United States mining. In addition to the hazards common to all mines, uranium mines have a complex health problem of radiation damage. Like many new processes, radiation and nuclear energy can be made to serve man in many useful ways when properly understood and handled; but, like fire, gases, and electricity, their potential dangers must be known and respected, and appropriate precautions must be taken or death may result. Since 1950 the Public Health Service has been conducting basic investigations on exposure to radon and its daughter products and the effect of exposure upon the health of miners in uranium mines of the Western States. The Bureau of Mines assisted in several of these investigations, especially in mines on Indian lands. The studies have shown that a serious health hazard exists from radioactive exposure that might cause lung cancer if continued over a number of years. The Public Health Service report, Control of Radon and Daughters in Uranium Mines and Calculations on Biologic Effects,6/ shows that 55 percent of the uranium mines employing 64 percent of the miners had atmospheric concentrations more than five times the working level now accepted as reasonably safe for industrial exposures. Extensive control measures are necessary to reduce these concentrations to the suggested working level of less than 300 micromicrocuries of total radon daughter products per liter of air.

Jan 1, 1958

By B. Qiu, Y. Luo

The design of the predriven recovery room is not an easy task, because the stress distribution in the barrier pillar, standing supports, fender pillar and the immediate roof is changing as the longwall face approaches the predriven recovery room. An analytical approach is proposed to determine the stress distribution in the barrier pillars, fender pillars, standing supports and immediate roof of the recovery room based on the fracture mechanics approach. Based on the developed mathematical model, a stand-alone computer program has been developed to facilitate the required computations. The parameters such as overburden depth, recovery room width, mining height, shield and standing support capacities are incorporated into this program to access the feasibilities of predriven recovery room designs. Compared to the finite element method previously employed, this analytical approach offers the same, if not better, accuracy without requiring expensive computer hardware and software or specialized expertise.

Jan 1, 2012

By J. P. Dunford

This U.S. Bureau of Mines report describes the development of a yielding steel post for underground mine support. The report covers concept development, laboratory tests, modifications, and field evaluations. The objective of this work was to develop a stiff support member capable both of supporting high loads and yielding when excessive amounts of mine entry closure were present. The 6-to 7-ft steel post was designed to yield nearly 2 ft while maintaining a 45-ton (force) load. The post is a three-piece unit consisting of top and bottom telescoping legs and a separate foot bracket. It develops its load-carrying characteristics when the lower pipe, with an attached interference ring, is forced into the larger top pipe. Laboratory tests were used to determine critical loads and post performance for various post lengths. Field tests showed that the posts could perform in actual mining conditions. The post has the ability to provide support in highly yielding ground and also, because of its slender profile, enhance ventilation and provide more area for travelways and escapeways. The design is simple enough to allow for fabrication at most mine shop facilities.

Jan 1, 1989

By Andrew Allan

During recent years underground production for the Pennsylvania anthracite region has reached the lowest output per man per day figure of the last decade and a half. This fact, combined with increased unit costs for labor and material, has forced the market price of anthracite ever higher. Over the years the mines have become deeper, and haulage distances have increased, thus adding to the mining costs. The industry now recognizes the need for new mining techniques to offset increasing costs. The Federal Bureau of Mines, through its Anthracite Research Laboratory, is engaged in a program of underground-mining research in cooperation with anthracite-producing companies to aid in reestablishing the economy of the region by introducing methods and/ or machines that will reduce underground-mining costs and, at the same time, enhance the safety of the workmen.

Jan 1, 1953

By W. M. Robertson

The rate of crack Propagation thvough a solid meta1 in the presence of a liquid metal has been calculated. The crack is assumed to propagate by solution of the solid in the liquid under the influence of an applied stress, with volume diffusion of the dissolved solute through the liquid controlling the propagation. The calculated velocities can be tens of centimeters per second or higher. THE embrittlement of normally ductile solid metals by liquid metals has been the subject of extensive study, as summarized in the book by Rostoker, McCaughey, and arkuus.&apos; In experimental studies of liquid-metal embrittlement it is usually concluded that the observed crack-propagation rates are too high to be accounted for by diffusion processes. Diffusion is considered to be an unimportant factor and various other mechanisms are invoked to account for the experimental observations. The similarities of liquid-metal embrittlement to stress-corrosion cracking, to hydrogen embrittlement of steel, and to low-temperature embrittlement of bcc metals are frequently used as analogies for these mechanisms.1"3 The present paper assesses how rapidly a crack could propagate by a mechanism of volume diffusion through the liquid metal. We assume that the crack propagates by solution of the solid in the liquid at the crack tip under the influence of the applied stress and diffusion of the dissolved solute away from the crack tip. The model uses only macroscopic thermodynamic, kinetic, and elastic concepts. The calculations indicate that this dissolution-diffusion mechanism can give high crack velocities. In some previous treatments4&apos;&apos; of crack propagation in a liquid-metal environment the fundamental step has been the breaking of atomic bonds at the crack tip. The liquid greatly decreases the energy necessary to break these bonds. The present model assumes the crack is filled with liquid metal; the presence of the liquid is essential because diffusion through the liquid is assumed to control the rate of propagation. With proper modification this model could also apply to stress corrosion in a liquid environment. THEORY Consider a crack in a homogeneous elastic continuum, ignoring all the structural details of the solid. This neglects a host of metallurgical details which can be significant in the problem of liquid-metal embrittlement;&apos; but this simple assumption is a useful approach in evaluating the role of diffusion through the liquid. The stress distribution around the crack tip establishes a gradient in the chemical potential at the tip, which causes a diffusion flux through the liquid away from the tip. The solid-liquid interfacial tension works against crack propagation, since propagation requires creation of interfacial area. From these two considerations we derive the diffusion flux, which then yields an expression for the velocity of the crack tip. The concentration of the solute in the liquid, C, is equal to the equilibrium concentration in the presence of an unstressed, flat surface, Co, plus the excess concentration due to the stress, AC(a), plus the excess concentration due to capillarity, AC(y): We calculate AC(o) and AC(y) and then obtain the diffusion flux. Consider (Fig. 1) a long flat crack of length 2L, thickness 2r, and tip radius r, where r remains constant as the crack propagates in the positive x direction. There is no stress ay in the y direction across the flat surfaces of the crack. The magnitude of the stress at the crack tip due to the applied stress, a,, is given by the relation6 ^=^[l-2^] 12] which, for long narrow cracks, becomes The stress increases the chemical potential in proportion to the strain energy.? The excess chemical potential due to the stress, Ap(a), is given by where 52 is the atomic volume of the solid and E the Young&apos;s modulus. Inserting Eq. [3] gives Now consider the crack to be filled with a liquid metal. The excess solubility due to stress, hC(a), is given by the excess chemical potential due to capillarity, Ap(y), is given by8 where y is the solid-liquid interfacial energy, and v1 and YZ are the two principal radii of curvature of any surface point. At the crack tip, r1 = -r and vz = m, so TRANSACTIONS OF THE METALLURGICAL SOCIETY OF AIME

Jan 1, 1967

By Alvaro Lucio

The continuous increase of the fuel oil price compelled CV3D to look for an alternative fuel. Charcoal was selected as the alternative energy source. This paper justifies its selection, describes charcoal properties, the methods for using charcoal in the pelletizing and shows the results of the in-plant tests.

Jan 1, 1982

By Tracy. L. D.

"Since the introduction of pulverized coal as a substitute fuel for natural gas in the various types of heating furnaces used, in steel mills, a number of fires and explosions have occurred, resulting in the loss of life and property.As one of the primary functions of the Bureau of Mines is to conduct investigations in the utilization of mineral substances with a view to increasing safety in the use thereof, it was deemed advisable to investigate the hazards involved in the industrial use of pulverized coal and, if possible, to devise methods of preventing future accidents arising therefrom. The knowledge of the explosive qualities of coal dust which the Bureau has gained in studies affecting dust explosions in coal mines was of material assistance in these investigations.Several plants were visited in which either fires or explosions had occurred, and data obtained as to the probable cause of the accidents.There was found to exist, among some of those employed about the furnaces, a lack of knowledge of the explosive and inflammable qualities of powdered coal.A small stream of pulverized coal leaking down from a defective joint in a coal transport line did not attract much attention, whereas, had a leak in a natural gas line occurred -wider similar circumstances, no doubt it would have had immediate attention.As a matter of fact, if by any means the duet cloud should come in contact with an open flame or hot metal, the effects would be as disastrous as if it had been gas.This is exceedingly well illustrated by an accident which came to the writer's attention. In the system used at this particular plant, the pulverized coal is transported to the furnace through compressed-air lines. The fuel is fed from a storage bin to a blowing tank in quantities as desired, after which compressed air is admitted and the powdered coal blown to the furnaces. At the time of the accident some repairs were being made to the tank, and it was supposed that the air pressure had been entirely released as the pressure gage stood at zero. There was, however, one or two pounds air pressure remaining and when one of the connections was taken off, a cloud of dust was blown across the room, 30 or 40 feet towards the drier furnace where it came in contact with some live coals. Immediately the entire room was filled with flame which rolled back and forth over a specs 50 feet or so in length."

Apr 1, 1921

By Rajesh Minda

160 numbers of double bulb underreamed piles were constructed based on the safe loads specified in IS code at Tripura. The pile load tests yielded a much lower capacity. A detailed investigation work was carried out to find out the reasons for anomaly. The work included soil exploration followed by extraction of two piles bearing numbers 72 and 151. It was seen that the bulbs were not formed as per specification. Some comments on IS Code have been made at the end.

Jan 1, 1996

By Amar Prakash, V. M. S. R. Murthy, VIVEK KUMAR HIMANSHU, Sufal Mehrotra, Ashish Kumar Vishwakarma

Raises are vertical or inclined openings made to connect two levels of an underground metalliferous mine. They are developed using drilling and blasting-based technique or by mechanical means. Raise boring machines (RBM) have evolved in recent years, which provide quicker and safer raise excavation. The penetration rate using RBM has influenced applied thrust. The required thrust to enhance penetration rate with optimal use of energy would be different under varying geological and geotechnical conditions. In this study, the influence of applied thrust on penetration rate using RBM has been investigated. The investigation has been made for two different rock types, amphibolite (AMP) and garnet-biotite-sillimanite-gneiss (GBSG). The numerical simulation model was developed for this purpose using Ansys-Explicit Dynamics. The induced tensile stress under different conditions of applied thrust has been analysed in the calibrated numerical model. The model output shows the power trend between the parameters. The experimental data on penetration rate was also collected along with the respective operational parameters. A statistical analysis has been carried out for the gathered data. The analysis of data also shows a power trend between thrust per cutter and penetration rate in both rock types and hence validates the numerical simulation-based output. Based on the outputs of the numerical simulation and empirical study of the experimental data, the optimum thrust per cutter for excavation in both rock types is in the range of 12–14 tons. The approach used in this study can be helpful for predicting the optimal operational parameters of raise boring machines under different geological/geotechnical conditions.

May 29, 2023

By A. L. Engel

In the period of 1942-1945, medium-grade, oxidized, lead-silver ore was mined and shipped from the Diamond district near Eureka, Nev. An encouraging tonnage of low-grade ore was developed during these operations and partly blocked-out for future mining. If the low-grade ore could be treated profitably, further development of the district would result, and production of an important strategic metal might be increased. A representative sample of Diamond district ore was obtained through the Reno office of the Mining Division for the studies described in this report. The sample consisted of lumps and fines of a highly altered siliceous rock containing much earthy red hematite and some granular black hematite. Examination with the binocular microscope showed the lead carbonate mineral, cerussite, in seams and disseminated in the hematite. No zinc or silver minerals were identified, and no sulfide minerals were present. Analyses of the ore showed:

Jan 1, 1951

By E. D. Stephenson

As part of the British Steel Corporation?s development plan during the 1970?s, it was decided to concentrate its bulk steelmaking processes based on the BOS at 4 major Works with access to deepwater ore terminals, for the supply of high-grade imported ores. These 4 sites were at: - 1. Rarenscraig Works in Scotland where the ore terminal would be hilt at Hunterston on the west coast some 50 miles away. Bavenscraig was already an integrated Works but suffered from having to discharge ore 27 Glasgow tenxinus on the River Clyde, which could only accommodate vessels up to 25,000 tonnes. In the future, ore was to be unloaded at Runterston and shipped by a rail-link into Ravenscraig, The new ore terminal would have the potential to unload vessels up to 300,000 tonnes. - 2. Port Talbot Works in south Vales where the existing harbour was developed to discharge large ore carriers. This again was an existing Integrated Works and the benefits of the new harbour also applied to Llanwern Works which was another integrated Works some 50 dies to the east, which would now receive ore from Port Talbot.

Jan 1, 1980

By Samuel P. Polack

This report reviews investigations to determine the fire hazard in coal mining when using flammable petroleum hydraulic oils to actuate mining equipment and summarizes research by the Bureau of Mines and industry on fire-resistant hydraulic fluids. Tests were established to evaluate fire resistance and the necessary characteristics to assure adequate service when fire-resistant fluids are used to replace petroleum hydraulic oils. The research was conducted in the laboratory and field trials under actual operating conditions in underground mines. Bureau of Mines Schedule 30 became effective December 17, 1959; the first approval was granted on February 18, 1960, and the twelfth was granted on March 17, 1961. The approvals include nine ready-mixed (by the producer) fluids and seven concentrates to which water is added by the user according to instructions from the producer. Seven synthetic-type fire-resistant hydraulic fluids submitted by two producers are also approved. Over 100 coal mines are now using water-in-oil emulsion-type fire-resistant hydraulic fluids in varying degrees from a trial in one machine to all the hydraulic equipment in an entire mine.

Jan 1, 1961

By Don L. Deardorff

The Deserado Mine and transportation system is the fuel supply portion of the Bonanza Power Plant project. Deserado Mine con¬sists of an underground mine with a capacity of 1,224,700 tonnes (1,350,000 tons) of clean coal per year, a 649 tonne (715 tons) per hour closed water circuit jig type preparation plant, a 5.6-kilometer (3 ½ -mile) overland conveyor with covered slot storage, a unit train rail load-out and 59.5 kilometers (37 miles) of totally independ¬ent, captive electrified railroad. Planning and exploration started in March of 1978. Construction of all facilities was completed in April of 1984, approximately six years after initial planning was commenced. This paper will discuss exploration, environmental permitting, mine planning, engineering and construction of the Deserado Mine project.

Jan 1, 1984