Search Documents

By Richard T. Stain

"In 2001, a pile trial site was established at Limelette in Belgium consisting of 25 displacement screw piles and 5 driven pre-cast piles. Interested parties were invited to participate in a pile prediction event, whereby they would submit predicted static load test behaviour in the form of load settlement plots. These predictions could be based on soil investigation results supplied by the organizers, or dynamic load test measurements.Following the submission deadline, the organisers released the results of static load tests for comparison.Of all the six participants, including Statnamic, the SIMBAT method was independently accredited with achieving the best predictions.This paper examines at the differences between SIMBAT and other systems, and presents the correlations from the Limelette trial.INTRODUCTIONThe Belgian Building Research Institute (BBRI) initiated an ambitious research programme involving the construction and testing of some 60 trial piles spread between two sites, a clay site at Sint Kateline Waver and a sandy site at the BBRI headquarters at Limelette. The project was financed largely by the Belgian Ministry of Economic affairs. (ref 1.) This paper refers only to the second site.At Limelette, six different types of displacement pile were installed: one driven pre-cast and five cast in place screw piles - Atlas, DeWaal, Fundex, Olivier and Omega. A detailed site investigation was carried out including in-situ and laboratory tests.An international pile capacity prediction event was publicised, participants being invited to predict static pile behaviour. Predictions could be based on:"

Jan 1, 2005

By Marco D. Boscardin, Benjamin H. MacKinney, Kenneth R. Allard, Kenneth A. Pidgeon, Adriane G. Boscardin

This paper presents a case history for a unique application of a system of vertical micropiles with horizontal soil nail bracing and shotcrete facing for underpinning. The system was used to support and protect an existing 2-story hospital building during demolition and renovation. The goal was to limit building movements and have the building remain in use during construction of an abutting addition. Soils at the site consisted of clean, loose to dense, sand and gravel. The original underpinning design was revised after the initial excavation revealed unsuitable soil conditions for traditional underpinning pits. An alternative system consisting of vertical micropiles (hollow bars) through the footing, combined with shotcrete and soil nails was proposed, accepted by the owner, and successfully constructed. Excavation depths were up to 15 feet (4.6 m) below the existing footings. Wall movements were monitored at regular, horizontal and vertical intervals along the hospital wall, and less than 0.6 inches (15 mm) of settlement and 0.1 inches (3 mm) of horizontal displacement throughout underpinning and construction were reported. The challenges with the original proposed support of excavation design and other alternative approaches considered will also be discussed.

Oct 1, 2022

By Fábio de São José

Sistemas de moagem são projetados baseando-se, entre outros parâmetros, no consumo de energia das rotas existentes. Consideram-se custos com energia um desafio para a indústria mineral, pois a maioria da energia disponível ao processo é inevitavelmente absorvida pelos equipamentos e somente uma menor porção é destinada à fragmentação desejada. Hoje, a maioria das teorias utilizadas na avaliação do desempenho energético parte dos estudos de pesquisadores como Fred Chester Bond. De acordo com Bond, Work Index (WI) é um parâmetro representativo da resistência à moagem do minério, servindo para medir o consumo de energia na fragmentação e para comparar o comportamento de diferentes minérios. Estudos recentes comprovam que o WI de materiais em mistura pode ser medido, geralmente, com alto desvio devido às diferenças existentes de moabilidade de cada tipologia. Este trabalho consistiu na determinação do WI de minério de zinco silicatado com elevações nos teores de esfalerita (ZnS) e galena (PbS), devido à avanços na lavra, minério composto unicamente por willemita e suas misturas. Valores encontrados mostraram que a presença significativa de minerais de classes distintas daquele predominante na frente de lavra pode influenciar na determinação de parâmetros importantes para o processamento mineral. Amostras foram fornecidas pela Votorantim Metais Zinco.

Aug 8, 2018

By J. B. Cunningham

Lithium in the form of metal, salts, and alloys is particularly important because of increasing industrial uses resulting partly from wartime developments. Lithium carbonate and lithium strontium nitrate, which impart a brilliant red color to a flame, are used in pyrotechnics. Lithium chloride and fluoride are used in fluxes for welding aluminum to dissolve the oxide coating on the aluminum and prevent oxidation of the molten metal. Lithium carbonate is used in ceramics in raw alkaline glazes because of its unusual fluxing properties. The use of 9 to 12 percent lithium carbonate permits a marked increase in the amounts of alumina, calcium, and silica that may be Used and results in a more stable glaze with sufficient alkalinity to produce vivid copper blues and other typically alkaline colors. Lithium stearate is used as a grease in airplane engines because of its ability to withstand wide changes in temperature. In view of its great affinity for nitrogen, hydrogen, oxygen, sulfur, phosphorus, carbon, and silicon, lithium has an excellent scavenging action on molten metals. It forms stable nonmetallic compounds of low specific gravity or gases that are eliminated at pouring temperatures. Lithium is generally added to the melt in the form of a lithium-calcium alloy consisting of 50 percent of each ingredient or as an alloy of 98 percent copper and 2 percent lithium. The lithium-calcium alloy added to cast iron before pouring, acts as a scavenger and increases the fluidity of the melt. This alloy also is said to increase the corrosion-resistant properties of stainless steel alloys and to improve their polishing qualities.

Jan 1, 1948

By Joel A. Hunt

The Bunker Hill Mine, located in north Idaho, consists of over 150 miles of passageways within highly fractured and faulted Precambrian metamorphosed rocks. The Bunker Hill Mine was at one time a major producer of lead and zinc; currently it is on inactive but maintained status. Ground water moving along flow paths that have been disturbed by mining reacts with pyrite and oxygen to produce acid water within the mine. Discharge of this acid water averages more than 5 cubic feet per second, with an average zinc concentration of 160 mg/L and pH of 2.8. Treatment of this acid mine drainage is required by the National Pollutant Discharge Elimination System (NPDES). Cessation of all underground activities at the Bunker Hill Mine will not terminate the production of acid mine drainage. Reclamation alternatives that could either reduce the quantity or Improve the quality of the drainage upon mine closure are highly attractive. This project is directed towards delineation of reclamation alternatives based upon an understanding of the characteristics of ground water recharge near the mine. A variety of field techniques were used to identify areas of rapid infiltration and to investigate the ground water flow system associated with the upper portion of the mine in a portion of the Milo Creek drainage. These techniques include Installation of piezometer nests, dye tracing, surface resistivity, dye dilution, spring surveys, and hydrochemical analyses. Sites of direct Infiltration into the mine have been located. These include mine workings directly below perennial streams, intersections between streams and faults, and a caved area adjacent to an ephemeral stream. Results of these investigations indicate that recharge through these sites is not as rapid as suggested by previous studies. Inflow to the underground workings from the ground water flow system around the margin of the mine may account for more mine water than sites of direct infiltration. Recharge control at areas of direct infiltration could result in a net decrease in the quantity of acid drainage from the Bunker Hill Mine. Locations suggested for recharge control are West Milo Creek above the Guy Caving Area, the intersections of the Cate Fault with South Milo and Milo Creeks, and an area of Milo Creek below the Milo Creek Dam that overlies shallow mine workings.

Jan 1, 1984

By Robert M. Becker

This investigation (in five parts) extends the theory of sample reliability from a sample consisting of a fixed number of items to a sample consisting of a fixed amount of items. Examples of a fixed amount of items per sample are samples consisting of a fixed weight or a fixed volume of unequal size particles. The extension of the theory is confirmed by experimental laboratory sampling using standard procedures. The probability distribution functions (the binomial, hypergeometric, multinomial, generalized hypergeometric, and those here called the compound binomial and compound multimomial functions) are developed from fundamentals. Their distributions are generalized to include some measured characteristic of the items. Infinite population moments are derived from moment-generating functions, and finite population moments are developed from corresponding infinite population moments using a newly defined mathematical operation. The first three experimental moments in laboratory sampling to given weights of particles are compared with the theoretical moments of their corresponding compound mult.inomial distributions. The agreement is striking. The study is divided into five parts. Part 1 deals with probability or random sampling to n items and with all sampling to n items per sample from some one probability distribution. This is the area of sampling covered by well-known theory. Accordingly, the procedures may be different but many of the results are well known.

Dec 1, 1964

By W. J. Wenger

THIRTY-FOUR analyses of crude oils from the fields of the Four Corners Area of Arizona, Colorado, New Mexico, and Utah are presented and compared. The samples, taken from formations in four geological time periods, have high gravity and low-sulfur, -nitrogen, and -asphalt content. Generally, the oils are paraffinic in the low-boiling fractions, with increasing naphthenicity in the higher-boiling fractions. Oils from Cretaceous formations resemble other Cretaceous oils in the Rocky Mountains, but oils from Permian and Pennsylvania formations are unlike other oils of these ages in the Rooky Mountains. The differences in the oils are minor and cannot be used to distinguish between fields or between producing formations. With minimum special processing, the oils should yield large amounts of good-quality motor fuels. INTRODUCTION The only place in the United States where four States have a common junction is known as the Four Corners Area. This area (fig. 1) includes the northeast corner of Arizona, the southwest corner of Colorado, the northwest corner of New Mexico, and the southeast corner of Utah. It includes three major geological basins: The Black Mesa, the San Juan, and the Paradox. Major oil developments have occurred in both the San Juan and Paradox basins, but no discovery of commercial importance has been made in the Black Mesa basin.

Jan 1, 1960

"4.1. IntroductionThis chapter reviews the geochemistry of the platinum-group elements (POE) in sulphur-poor silicate rocks, and the limited data on POE in silicate, oxide, sulphide, arsenide and sulpharsenide minerals. The earliest geochemical studies of POE in silicate rocks, minerals and meteorites were carried out mainly by Goldschmidt, the Noddacks and their co-workers, and are reviewed in Crocket (1969). These researchers established the siderophile character of the POE, emphasized the common association of the group with sulphides in ultramafic-mafic rocks and suggested that very low concentrations of POE are typical of sulphur-poor silicate rocks and minerals. Much of these data were for Pt and Pd only and are more than 50 years old. Because of the poor sensitivity typical of the available analytical methods, few reliable data were obtained on silicate rocks in these early studies. Surveys of POE geochemistry demonstrate that the data base for sulphur-poor silicate rocks is very restricted, although considerable highquality data for Pd and Ir have been accumulated (Wright and Fleischer 1965, Yushko-Zakharova eta/., 1967, Mertie 1969, Crocket 1969, 1979, Keays 1981).Two recent publications, Vol. 71, No. 7 (1976), of Economic Geology (An Issue Devoted to Platinum-Group Elements) and Vol. 17, Part 2 (1979), of The Canadian Mineralogist (Nickel-Sulphide and Platinum-Group-Element Deposits), are of special interest. These volumes are clear testimony to the impressive progress made in the last decade toward describing the mineralogical and geochemical aspects of POE ore deposits, but at the same time demonstrate the constraints in modelling POE ore genesis due to our meager knowledge of the. POE content and distribution among minerals in the source rocks of ultramafic and mafic magmas. It is clear that the phases hosting POE in mantle source rocks are poorly understood. Nevertheless, Naldrett and Duke (1980) have shown that the absolute and relative concentrations of POE in magmatic sulphide ores are related to the degree of partial melting of mantle peridotites, and subsequent processes of batch equilibration and fractional segregation of sulphides."

Jan 1, 1979

By G. R. Hopkins

For several years prior to about the middle of 1928 both the number and capacity of natural-gasoline plants showed a steady increase; this resulted from a material gain in the supply of casinghead has due to the discovery of a number of flush fields with relatively high gas-oil ratios. From 1928 to date some form of proration has been continually in force, with a consequent curtailment in the supply of wet gas. This decline in available gas and a severe decrease in prices, due largely to the increasing competition of light refinery products, has eliminated virtually all of the weaker units during the last 5 years, with the result that the number of plants declined from 1,155 on January 1, 1928 to 19035 on January 1, 1930, to 909 on January 1, 1932, and then to 859 on January 1, 1934, The struggle of the small high-cost producers to exist is illustrated further by the trend in the number of shut-down plants, which has increased from 36 on January 1, 1930 to 100 on January 1, 1932 and to 128 on January 1, 1934. The increase in the number of plants prior to 1929 resulted in a material gain in the total capacity, but the decline in number between 1929 and 1932 was not followed by a corresponding decrease in capacity, as gains resulting from the construction of a few very large plants overbalanced the loss due to the dismantling of a large number of small ones. However, the low prices of 1932 and 1933 supplied little incentive for new construction, and the total capacity declined in approximately the same ratio as the number. Thus the total capacity declined from 11,387,000 gallons daily on January 1, 1932 to 13,060,000 gallons daily on January 1, 1934, Of the latter 9,181,000 gallons (91 percent) represented the capacity of the operating plants and 679,000 gallons (9 percent) the capacity of the idle plants.

Jan 1, 1934

By T. Hawthorne, H. Barnes

Homestake Mining Company has developed an estimating model, based on other closed projects, to audit and prepare new estimating plans. The results of recent closure audits reveal that the original budgets were often insufficient to cover the present expected expenses. Some of the major areas where technical challenges and costs are increasing include heap leach pile detoxification and rinsing, tailings dam closure, water management and treatment, abatement of contaminated soils, and many others. Risk and sensitivity analysis of each category will develop a level of confidence in the estimate and allow management to focus on the pertinent issues. Periodic audits of closure plans and costs throughout the life of mine serves to focus management attention on the complete costs of production. This will result in improved overall planning and management, and reduce the number of missed opportunities for savings.

Jan 1, 2000

By J. de Bakker

It hardly needs to be repeated that if coal is to continue as America’s premier source of cheap energy, it is absolutely necessary that the carbon dioxide from its combustion somehow be sequestered. A promising method proposed to accomplish this is the “indirect” carbonation of serpentine in a concentrated magnesium chloride brine. Indirect carbonation could be also applied to precipitate magnesium in lateritic nickel processing: this would not only solve magnesium-control problems in laterite hydrometallurgy, but also reduce its energy requirements and create CO2-sequestration credits. Fifty-five percent of the electricity generated in the United States comes from coal-fired power plants, and American coal reserves can last over 500 years at 1990-level consumption1. Coal is therefore both abundant and cheap: it could (and in fact probably will) continue to be an affordable source of energy, both for producing electricity and as a feedstock for liquid hydrocarbon production by Fischer-Tropsch reactions. As a result, it is important to find a workable method of permanently sequestering CO2.

Jan 1, 2007

By A. R. Byers

"This paper describes the distribution, occurrence, and paragenesis of known sulphide deposits within an area bounded by longitudes 102°00' to 106°00' west and latitudes 54 ° 301 to 57 °00 1 north. The Precambrian bed-rock which outcrops over all but the southern fringe of the area con- . sists of regional metamorphic assemblages ranging from low grade or green schist facies to high grade or amphibolite-granulite facies. The areas . of low-grade metamorphism correspond to 'islands' of volcanic rocks which are surrounded by highgrade paragneisses and migmatites. Intrusive rocks range in composition from ultrabasic to granitic and may be divided into syntectonic and posttectonic sequences. The average composition of the former is granodiorite and of the latter quartz diorite.The massive sulphide deposits fall naturally on basis of mineral content into the following divisions: ( 1) pyrrhotite and / or pyrite, (2) sphalerite and/ or chalcopyrite plus iron sulphides, (3) sphalerite and galena, ( 4) sulphide-bearing pegmatite, and (5) nickeliferous pyrrhotite and / or chalcopyrite. The deposits of iron sulphides are ubiquitous. Ratio of pyrrhotite to pyrite is fairly constant for individual deposits, but their areal distribution appears to be independent of the nature of the enclosing rock and grade of regional metamorphism. All deposits containing ore-grade quantities of base metals have been concentrated at favourable structural locations. Copper-zinc and lead-zinc deposits appear to be associated with syntectonic granodiorite with the lead-zinc concentrations confined to calc-silicate gneisses. Copper-nickel deposits show a close relationship to post-tectonic gabbros and pyroxenites. The paragenesis is more or less the same for the majority of deposits, with iron sulphides and sphalerite being introduced early and followed by chalcopyrite and galena. Some vertical and / or horizontal zoning is apparent in a few deposits. Temperatures of formation and origin of the deposits are briefly discussed."

Jan 1, 1960

By W. G. Diamond

Lightweight aggregates have become increasingly important to the construction industry. From 1953 to 1960, the quantity of the aggregates used in concrete block, precast and prestressed concrete, and monolithic structures increased about 92 percent. The present study was conducted in Bureau of Mines Area IV which encompasses the South-Central States of Arkansas, Kansas, Louisiana, Mississippi, Missouri, Oklahoma, and Texas. This is an administrative area and does not delimit a market area or imply an economic unit. Because of the increasing importance of metropolitan areas in evaluating economic growth, significant data showing relationships between growth of the metropolitan areas and the lightweight aggregate industry are included.

Jan 1, 1964

By S. J. Aresco

The Bureau of Mines has been active in promoting the purchase of coal for Government use under specifications that define the requirements in terms of heating value of the coal, expressed in British thermal units, and the composition as shown by proximate analyses. To these, when required, are added the ash-softening temperature, the free-swelling index, and the Hardgrove grindability index. Under most of these specification contracts the bidders guarantee the quality of the coal, and that guaranteed by the successful bidder becomes the standard of his contract. The deliveries are sampled in accordance with instructions4/ issued by the Bureau of Mines, the samples are analyzed in the Bureau laboratory to determine whether the coal is of the quality guaranteed by the contractor and, if it is not, a price adjustment is made. Analyses of the delivered coal and tipple samples (samples collected at mine tipples as coal is being loaded into railroad cars or trucks) provide valuable data for use in evaluating future bids. In addition, the continuous sampling of coal as delivered is a check on the practical results obtained in burning the coal.

Jan 1, 1957

By R. L. Benner

The Bureau of Mines investigated the ZnO-Fe2O3-Fe3O4 system at 1,000°, 1,300°, and 1,400° C, with oxygen pressures between 1.0 and lx10-4 atmospheres. The results, divided into the thermodynamic properties as related to the spinel structure, and the thermodynamic properties as related to zinc concentrate roasting, were used to calculate the activities of ZnO, Fe2O4, and Fe3O4 within the spinel solid solution region of the ternary system, and the pseudo-binary activities of ZnFe2O4 and Fe304. The activities of both systems show large positive deviations from Raoult's Law, especially at high Fe3O4 concentrations. The free energies, the enthalpies, and the entropies of mixing for the binary system were calculated from the binary activities, and the entropies of mixing were compared with two statistical models, one representing an ideal solution, and one representing the mixing of a normal with an inverse spinel. The binary entropy of mixing seemed to be better represented by the latter statistical model, indicating that the tetrahedral and octahedral cations of the reactants tend to remain in the product, even at the high temperatures of the study. This comparison also indicated that the cations of the components are the major contributing factors to the thermodynamic properties.

Jan 1, 1966

By Donald W. Ross

"INTRODUCTION Sponge iron has been made commercially since 1912 at a Swedish ceramic plant; and the product, known as Swedish disk—type sagger sponge iron, has an excellent reputation as a superior furnace feed wherever high—grade steels are made. The general procedure for making brickyard sponge iron was described frequently in Swedish technical journals prior to 1932 and at that time consisted in filling clay refractory containers, called saggers, with a super-concentrate of Gellivare magnetite plus the necessary amount of solid reducing agent and desulfurizer and then firing in a Hoffmann ring furnace, as used in the ceramic industry.The early Swedish publications describe two types of brickyard sponge iron: (1) An inferior high-sulfur product obtained by mixing the ore and reducing agent, and (2) a high-grade low-sulfur product in the form of coherent disks 7 to 9 inches in diameter and 1 to 1-1/2 inches thick made by the saggers with alternate layers of solid-fuel reducr and of uniaxed ore."

Sep 1, 1945

By E. A. Clarke

The vapor-phase section of the Coal Hydrogenation Demonstration Plant at Louisiana, Mo., was operated for the first time in April 1949. The run lasted only 10 days because of time limitation (pending plant dedication in May) and the small amount of charging stock available. The primary purpose of the operation was to break in and determine the operability of the equipment and to supplement the operators' classroom training with actual practice by operating the plant under mild conditions. A secondary aim was to obtain data on the hydrogenation of petroleum oil and lignite tar distillate at approximately 10,000 p.s.i. while making gasoline and Diesel fuel oil. Although the operations were carried out under conditions considerably below those used in the plant design, a great deal of experience and data was obtained. As it is not feasible at this time to conduct further vapor-phase operations on similar stocks, this report has been prepared to present and summarize the data obtained through this operation.

Jan 1, 1950

By P. Cain, B. Martens

"Grande Cache Coal (GCC), an investor-owned Alberta company, is in the final stages of the regulatory process leading to the resumption of coal mining in the Smoky River Coal Field of Alberta. Although many opportunities for low-cost, high-yield mining remained on the property, GCC opted for a long-term production plan that ensures stability for the local economy, sustainable use of the resources in the area, environmental responsibility and a satisfactory return for its investors.GCC entered the Alberta coal approval process in late 2000 with a public disclosure document. In October 2001, GCC formally submitted an application for mining approval and an environmental impact assessment (EIA) to the government and the public. The application covered the proposed Grande Cache Coal project, which includes the No. 7 underground mine, No. 8 surface mine and coal processing operations. The EIA provided a comprehensive investigation of environmental sensitivities in the project area, matched with environmental protection programs. The project is based on commencement of operations in late 2002. GCC’s plans are founded on a commitment to sustainable development and has framed this commitment in the context of a long-range mine development plan that will sustain the community of Grande Cache over the next 25 years. The Grande Cache coalfields offer extensive coal reserves and opportunities, for both surface and underground mining. Combining highly productive U.S.-style room and- pillar underground mining methods and conventional truck-and-shovel open pit mining, GCC’s approach to sustainable development encompasses community involvement and reclamation of mine sites to productive land uses after mining."

Jan 1, 2002

By Vernon Helm, John S. Ball, Welton J. Wenger, William E. Haines

"INTRODUCTION Although the presence of sulfur causes many petroleum’s to be classified as ""low-grade"" because of the difficulties encountered in manufacturing products to meet rigid specifications, the petroleum industry is finding it necessary to use such crude oils to satisfy present needs. As the demand for petroleum products increases, and available reserves diminish, this utilization of high-sulfur crude oils will be accentuated. Programs designed to supplement the supplies of fuel available from petroleum by the manufacture of synthetic fuel from natural gas, shale oil, and coal are in progress. Such fuels, especially shale oil and, less so, oil from the hydrogenation of coal, also contain sulfur compounds which must be effectively removed. Thus, the need for fundamental research on the sulfur compounds that may be expected in petroleum and allied products is becoming greater as the industry is forced to call upon all available resources to meet the demand for petroleum products. In recognition of this need, the Bureau of Mines has inaugurated a long-range program assigned to furnish fundamental data concerning the presence, characteristics, and effects of sulfur compounds in petroleum and its products."

Dec 1, 1946

By H. M. Coggin

The study summarizes the state of the art in rock mechanics, open pit and underground mining, leaching, geology, metallurgy and financial analysis Conceptual design of pit slope caving technique and analyses explore concepts for the exploitation of ore grade remnants in the walls and bottoms of open pit mines and the potential economics of the adaptations Several coded sites were examined for future studies where the feasibility of the method may be demonstrated. An extensive bibliography has been developed

Jan 1, 1977