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Comparative tests of four coals used industrially for coke production have been made by three laboratories of the Federal Bureau of Mines, each using its standard equipment and procedures for evaluating coal for coking. Two of the coals were blends used in the western and eastern sections of the United States, the third was a strongly coking coal widely used for producing coke in Alabama, and the fourth was a blend typical of those used for producing foundry coke in the Birmingham district. The coals used and the cokes produced from them covered a wide range of chemical and physical properties. The tests used at all three laboratories for determining the physical properties of the cokes were made according to ASTM (American Society for Testing Materials) methods. The excellent agreement found for the physical properties of the cokes indicated that, for the coals tested, the BM-AGA (Bureau of Mines-American Gas Association) 18-inch circular retort used at Pittsburgh, Pa" the 14-inch slot-type oven used at Denver, Colo., and the 17-inch slot-type oven used at Tuscaloosa, Ala., were substantially equivalent for evaluating coals for production of coke. Thus, added value is given to data obtained previously and independently at these three Bureau laboratories. INTRODUCTION Laboratory equipment to produce coke for evaluation has not been standardized by the industry. The results obtained with anyone design of equipment have been regarded as showing only the relative values of coal to produce coke of the requisite quality. Few systematic studies have been made to correlate results obtained in different types of equipment. Results of one, in which the Bureau of Mines participated, were published recently.2/ This

Jan 1, 1961

A general outline of the significant features in the quality and manufacture of the more common refractories is given. Where possible, linkage between quality development and control and service applicationhas been shown and explained. INTRODUCTIONThe refractory industry is no stranger to change. New processes and revision of old processes in other industries are the harbinger of new and revised products in refractories.Few of the changes are dramatic; generally they are evolutionary rather than revolutionary. New developments are additional to, and inclusive of, established practice.Therefore in this paper it is necessary to repeat much of what is already known in order to show the development taking place.FIRECLAY REFRACTORIESGeneral technology Fireclay refractories are the most common, the most varied and the most versatile of all refractories. Virtually any composition of silica and alumina up to the composition of kaolin is possible. For purposes of comparison they may be classified in the Continental fashion in accordance with chemical composition or in the American way according to "duty". That the two methods are equivalent is shown by an inspection of the alumina-silica diagram of Bbwen and Greig (1924). 'Fireclay refractories are composed of a glassy and a crystalline component derived from the chemical and physical nature of the raw materials used in their manufacture.

Jan 1, 1961

By Ronald S. Conti

The Bureau of Mines conducted a comprehensive laboratory study of the thermal ignitability of various carbonaceous dust clouds with particular emphasis on various ranks of coal dust. The tests were conducted using a new 1.2-L furnace. Autoignition temperatures of dust clouds were obtained as a function of coal volatility and particle size. Dust particles and gas samples were collected by a rapid-sampling system in order to study the reactions involved in preignition and postignition processes. The autoignition temperatures measured in the new 1.2-L furnace were significantly lower and therefore more conservative than those measured previously in the Godbert-Greenwald furnace. The combined effects of thermal and electrical ignition of dust clouds were also studied in the 1.2-L furnace using electrical discharges of varying energies at ambient and elevated temperatures. The minimum spark energy necessary to ignite a dust cloud decreased significantly as the temperature of the dust cloud increased.

Jan 1, 1983

By Richard C. Moore

The U.S. Bureau of Mines contracted a study to review the air and water monitoring requirements of five Federal environmental acts (the Federal Water Pollution Control Act, the Safe Drinking Water Act, the Clean Air Act, the Surface Mining Control and Reclamation Act, and the Resource Conservation and Recovery Act) and to compile information on the currently available monitoring instruments. A literature review of the acts and their associated regulations was conducted to determine applicability to the mining industry as well as any air and water monitoring requirements. In addition, an industry search and literature review was performed to assess the instrumentation available to comply with the monitoring regulations. Based on this research, the instruments are classified by general applicability to air, surface water, or ground water monitoring, then catalogued by monitoring parameters. A discussion is provided on recommended and innovative monitoring techniques.

Jan 1, 1981

By T. Negeri, M. Boisclair

"A hybrid process consisting of flotation and magnetic separation has been developed to concentrate multi-phase rare earth minerals associated with a carbonatite ore that contains a significant amount of niobium. Fine grinding to a d80 of <65 microns was required to obtain acceptable separation of 92% of the contained total rare earth oxide (TREO) and niobium in half the feed mass. Whereas it was possible to obtain 85% of TREO in 28% of the feed mass through staged cleaning, it was demonstrated that at least 87% and 85% recoveries of TREO and Nb respectively could be achieved in 16% of the feed if the rougher-scavenger concentrates were calcined, quenched, reground to <25 µm and then magnetically upgraded. The paper discusses the overall concept of the flowsheet and the experimental strategies that led to this progress. INTRODUCTIONOut of the approximately 250 minerals known to contain rare earth elements (REEs), only about 60 of them contain REEs in significant amounts. Over 95% of the world’s rare earth oxides (REOs) are believed to occur in the form of three minerals (Pradip & Fuerstenau, 1991) namely bastnaesite (Ce,La,Y)CO3F, monazite (Ce,La,Nd,Th)PO4 and xenotime Y(PO)4. An estimated 51.4% of global REO resources are hosted by carbonatite deposits with the same three minerals as major constituents (Weng et. al., 2015). Any one of the REEs or commonly all of them can be found in these minerals (Ravnaas, 2010). As the demand for critical REEs increases due to the ever increasing applications in advanced technologies, many deposits containing other forms of REE minerals will have to be developed. REE minerals are extensively dispersed and intergrown with several oxides, silicates, carbonates, and phosphate minerals. Consequently it is possible to liberate them only at fine grinding and is thus difficult to separate and produce high grade rare earth mineral concentrates. Most of these minerals contain other important elements such as tantalum (Ta), niobium (Nb), uranium (U), and thorium (Th) in varied quantities. REE minerals in the same ore may exist as carbonates, fluorocarbonates, niobates, silicates, phosphates etc. in association with gangue minerals belonging to different mineralogical groups."

Jan 1, 2016

For the third successive year it appears that demand for platinum will exceed supplies of newly-mined metal, forecasts Johnson Matthey in its "Platinum 1987 Interim Review." Based on data available at the end of August 1987, Johnson Matthey estimates that western world demand for platinum could exceed 93t (3 million oz) for the first time ever in 1987. Given a likely increase in demand of 4.3t to around 94t (140,000 oz to around 3.02 million oz), up by about 5% over 1986, there would be a 1.8- to 2.2-t (60,000- to 70,000-oz) shortfall in 1987 supply. South African mines enjoying undisrupted production last year after strikes affected Impala&apos;s output in 1986. The rate of increases in western world supplies, though, has probably not kept pace with the growth in demand. A downturn in US demand for platinum was counterbalanced by substantially increased purchases from Japanese and Western European consumers of the metal. Total imports of platinum into Japan in 1987 may have reached a record level of 45t (1.45 million oz). The largest source of demand for platinum remains its use in autocatalysts US and Japanese auto manufacturers reduced their platinum purchases in the wake of falling car production. Therefore, a small decline in overall 1987 sales of perhaps 780 kt (25,000 oz) was expected in 1987. Western European demand, however, rose strongly as a result of increased output. The spread of exhaust emission control regulations has sharply boosted the number of cars equipped with three-way catalysts containing platinum and rhodium. Western European auto makers probably needed 5.6t (180,000 oz) of platinum last year, a 50% increase over 1986. The jewelry industry, the second largest user of platinum, increased its offtake of platinum in 1987. Japan, the key to the jewelry industry&apos;s consumption of platinum, could absorb 24.8 to 26.4 (800,000 to 850,000 oz) in 1987, compared with 23t (740,000 oz) in 1986. Platinum has wide and diverse applications in industry. Other major users are the chemical, glass, electronics and petroleum industries. They were expected to increase their aggregate demand by about 1.8t (60,000 oz), or 11% in 1987. Investment demand for small platinum bars and coins of up to 311g (10 oz) dropped back in relatively inhospitable conditions. This, after rapid increases in recent years and a surge in US demand in 1986. However, Japanese investors purchasing bars weighing 500g or 1 kg (16 to 32 oz), and considered more speculative, recovered last year. Over the first eight months of 1987, platinum performed strongly on the open market with average prices well up from 1986 in dollar terms. But the increase was less marked where measured in sterling or yen. Platinum ad¬vanced by $3.70/g ($115 per oz) between Jan. 1 and mid-September with the average price having been surpassed only in the heady days of 1980. Johnson Matthey believes that supply and demand appear likely to keep more or less in step on a gently rising path. The recent open market volatility will continue with prices fluctuating widely over short periods. Writing in mid-September, and basing its view on the tangible evidence of platinum&apos;s price fall since the review was written, the company&apos;s assessment of price prospects is unchanged. Demand for platinum remains strong all-round. In October, imports of platinum into Japan were exceptionally high. And in the US and Japan there was a marked resurgence of demand from private investors. Although market sentiment may have been influenced in part by the news of several potential new platinum mines in South Africa, the full effects of these prospects on supply, even if they were all to materialize, would not be felt before the early-mid 1990s, Johnson Matthey said. According to the review, no radical change in platinum supplies is discernible in the near-term. Incremental growth from South Africa can be expected as the major producers continue to make the most of their existing resources. The Soviet Union may be keener to sell than it appeared earlier in 1987, especially if prices hold up, but a substantial increase is improbable. Canadian supplies are not capable of much variation from present levels. The palladium-rich Stillwater mine will make a modest contribution. Referring to the investment market, Johnson Matthey concluded that despite this year&apos;s reduction in sales of small-denomination investment products, platinum does appear to have established itself with private investors. Bearing in mind how business multiplied in comparatively unfavorable conditions before 1986, it is reasonable to look for a resumption of growth once the climate improves.

Jan 2, 1988

By Makhlouf Boubahziz

The HNIA field is part of the Tinrhert project which consists of developing 17 fields containing essentially gas with a few small rings of oil. It is considered as one of the main fields in this project in terms of its area and the number of geological structures that has formed it. It is a wide anticline of Cambro-Ordovician age, orientated NNE-SSW and located in the South-eastern part of Illizi basin. This structure extends from Alrar-center in the North, to the North of In Amenas in the South. The area is 1350 km2. The main reservoirs forming HNIA field are the Devonian (F2, F3 and F4), Siluro-Devonian (F6) and Cambro-Ordovician. These latest are formed by 4 sandy units alternated by layers of shale and shaly silt termed from the base to the top as follow: Unit II, Unit III-3U, Unit IV-2L and Unit IV3; these units are the subject of this study. The HNIA field is essentially gas, up to day this field is at the stage of appraisal and evaluation in order to establish a development plan; therefore the main target of this study is to contribute to this frame work. The following objectives are: ?To build a structural model of the study area. ?To integrate all the sedimentological, structural and petrophysical data in order to build a 3D geological model

Aug 1, 2013

By J. W. Jensen

This report was prepared as a background reference for future publica¬tions concerning the damping capacity of metals and alloys. It contains a broad description of the theory and methods of measuring damping capacity and correlates the developments of the past decade in terminology, units, and techniques. Damping-capacity instrumentation at the Mississippi Valley Experiment Station, Rolla, Mo., is described. The bibliography contains over 150 references to recent articles, each tabulated as to material investigated and test variables, such as frequency, stress, mode of vibration, and temperature. INTRODUCTION After it discovered high-damping manganese-copper alloys before World War II, the Bureau of Mines began research on the damping capacity of alloys and has continued to expand this activity to the present time. In physical metallurgy, damping capacity has become an important research tool in the Bureau. The physical measurement of the damping properties of alloys was begun at the College Park laboratories, and later conducted at Salt Lake City under the direction of Dr. E. V. Potter. Among the many articles resulting from this work, Damping Capacity of Metals (108)3/ has received frequent men¬tion in more recent literature and describes briefly the methods of measurement employed at that time.

Jan 1, 1959

By R. A. Beall

Homogeneous zirconium-alloy ingots have been cast on a production basis by the consumable-electrode arc-melting process at the Northwest Electrodevelopment Experiment Station, Bureau of Mines, Albany, Oreg. This paper describes the various methods used to introduce alloying materials into the ingot and evaluates 1 each method by the degree of homogeneity of resulting ingots, as determined in tests on sections cut from the ingots. As many as 30 or more ingots, each 6 to 10 inches in diameter and weighing 300 to 500 pounds, were melted, using each method; and, as most of them subsequently were fabricated to strip 0.1 inch thick, the test results are considered to be representative of production practice. Ingot homogeneity has been considered more difficult to achieve in arc-melting practice than by methods where the molten metal is poured into molds and the addition can be stirred into the total mass of metal before casting. Owing to the unique requirements of consumable-electrode arc melting the addition can be made only to that part of the total mass of the ingot that is molten at one time. Observation of the flowlines in 500-pound ingots produced at Albany indicates that the molten pool has a maximum depth about equal to the ingot diameter. The weight of metal molten at one time is, therefore, not over 100 pounds. Characteristically, the arc-melting process is conducive to segregation, which can be overcome, at least partly, by adding the alloy constituents almost continuously during casting.

Jan 1, 1956

By Jones S. C

The problem of sealing a fluid serieite zone at a hole depth of 4000 ft was overcome by using a composite non-return valve plug and rod assembly which enabled cement to be forced under pressure into the zoneà

Jan 1, 1966

By Jin Dai, Xianwen Geng, Hao Liu, Pu Wang

To investigate how deformation failure occurs in roadways surrounding rock, the relationship between cohesion and plastic shear strain of the strain softening model and the equation for calculating the shear strain of a rock mass in the ultimate elastic state are derived. On this basis, the equality relationship between the built-in maximum shear strain increment and cohesion of FLAC 3D was established to give a more intuitive picture of how the cohesion of the roadway surrounding rock changes. The cohesion attenuation and deformation of the surrounding rock are analysed. The results show that significant deformation in the roadway surrounding rock was caused primarily by the development of large areas of highly softened plastic rock masses towards residual strength. Taking the floor overhead-mining roadway under different rock pillar thicknesses (RPTs) in the Xinglongzhuang Coal Mine as an example, the results demonstrate that investigating the cohesion distribution inside the roadway during mining operation can provide a more intuitive, more accurate description of the degree of failure of the surrounding rock at any point of the roadway, as well as the overall failure range of the surrounding rock. The simulation agrees well with the field monitoring result and seems to be more practically useful than simply analysing the coverage of shear plastic zones. Based on the failure range and degree of roadway surrounding rock with different RPTs, three support schemes are designed. Classified support was implemented for roadways under different RPTs, which realizes the effective control of roadway surrounding rock.

Jan 16, 2022

By T. Muldoon

Literature review and extensive field survey of line and check curtain materials and practices showed: ? Miners, in general, know how to set tight curtains, and do so when needed. ? The tradeoff is economic; tight ventilation is labor-intensive. Line and check curtain techniques found are catalogued and evaluated. A fieldworthy 10 ft extensible brattice to maintain a 10 ft setback was found in use in two mines on continuous miner faces. This technique was evaluated in the laboratory for leakage and methane control at the face. Significant results include: 1) Air leakage through a gap in the extensible curtain depends upon the ratio of the cross-sectional areas between entry and return as well as gap area; 2) Gap shape has no significant effect on methane concentrations at the face -increasing gap area diminishes ventilation effectivness; and 3) Substantial reductions of CH4 concentrations at the face were accomplished by brattice extensions with gaps of up to 5 ft2 in area. An "inby hook," inserted in the roof automatically to make possible the deployment of a longer (20 ft) brattice extension in the context of a remotely controlled miner, was tested in various roof types. Insertion of this design succeeded only in coal.

Jan 1, 1982

By Clyde N. Baker

Foundations for the Sohio Corporate Headquarters in downtown Cleveland have column loads of 11,400 kips, which increase to 15,000 kips with wind loading. An extensive exploratory program was conducted and comprehensive studies made to select the economically dependable support for the 46-story structure. A test on bond or socket friction for the caissons has usable values.

Jan 1, 1984

By Lloyd Williams

1. This investigation shows that the Sewanee bed is the only coal bed being mined in Sequatchie County. Other coal beds are present, but as they do not contain known recoverable reserves, estimates of reserves were made only for the Sewanee bed. 2. Known measured and indicated reserves in the Sewanee bed, based on a minimum thickness of 14 inches and on 1,800 short tons per acre-foot of coal in place, are estimated to be 76 million short tons as of January 1, 1953. Of this total 62 million short tons represent coal 28 inches and more thick. Areas in the bed were omitted from the estimate because available data relative to the bed characteristics were insufficient to permit making an estimate conforming with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves determined by this investigation.

Jan 1, 1955

By Ronald Ticona, Jair Alarcón

Generalmente, la operación de perforación y voladura se gestiona de forma independiente a los resultados de la planta de procesamiento. Por lo tanto, la segmentación técnica para determinar los diseños de perforación y voladura del mineral no incluye las propiedades de la roca de la planta de procesamiento, como el Bond Work Index, Axb, Drop Weight Index u otros. El año 2021, en la operación de una mina de cobre del Perú, de acuerdo a su plan de minero tendría una dureza de molienda SAG significativamente mayor, lo que impactaría directamente en la producción de concentrados de cobre. Se volvió necesaria la búsqueda una estrategia integrada entre mina a planta para mantener los niveles de producción.

Sep 30, 2022

By Clarke E. Schuetze

This project had as its objective the experimental investigation of water capsule production utilizing the Southwest Research Institute&apos;s submerged nozzle encapsulation apparatus (U.S. Patent 3,389,194). Initial efforts on this project involved nozzle configuration and shell formulation optimization. The shell formulation developed on a prior program was modified during the course of the project to obtain the best balance of capsule breakage resistance and water retention. Subsequent effort centered on determining operating conditions which would produce the best quality capsules for each candidate shell formulation as determined by laboratory tests. Some preliminary work was done to increase the production capacity of the encapsulation equipment. The program was extended with major emphasis concerned with scale-up studies of capsule production capacity and the treatment of problems associated with grouting cartridge fabrication. During the course of the program, water-containing capsules were produced which have good long-term water retention, block resistance and adequate strength. Using a single-nozzle design, a production capacity of 15.9kg (35 pounds) per hour was demonstrated to give acceptable capsules based on initial results.

Jan 1, 1978

By D. J. Robertson

"THE copper smelting operation of the Hudson Bay Mining and Smelting Company, Limited, at Flin Flon, Manitoba, generates a gas flow of 350,000 c.f.m. at n.t.p. This gas stream passes to atmosphere through a 20-foot diameter by 250-foot brick stack, carrying with it an appreciable dust burden in the form of metallic oxide fumes. The flow constituents during the period 1952 and 1953 and •before gas filtration was included in the treatment scheme are shown in Table I. This paper describes the gas filtration treatment which was installed in 1957, using glass cloth media to recover this dust burden, and discusses the associated problem as its treatment for recovery of zinc and cadmium.The metallurgical details associated with the problem are illustrated by a description of the material flow sequence of the Company's hydrometallurgical zinc plant and copper smelter. In this ore processing complex, the zinc plant and copper smelter form an integrated unit within which intermediate zincrich products of each operation enter the treatment circuit of the other."

Jan 1, 1960

By P. Somasundaran, Tarun Bhambhani, S. Murthy Khandrika, Partha Patra, D. Nagaraj

Fine and ultrafine mineral particles, particularly if, altered mineralogically, can have detrimental effects on selective separation of minerals. Behaviour of altered mineral fines has been investigated in this work by studying the effects of weathered silicate slimes on the selective separation of copper minerals, particularly with focues on effect of the pulp rheological behaviour, which plays a governing role in the process. Physicochemical properties of these altered silicates fines such as morphology and surface charge are proposed to be responsible for the adverse rheological effects and resultant selective separation. Here, the effect of a number of problematic aspects such as water chemistry, froth stability, physicochemical aspects of gangue mineral aggregates on flotation sub-processes has been studied. Processing problems owing to the physical aspects of the gangue minerals, shape and morphology, are primarily due to uncharacteristic increase in the pulp viscosity. While problematic aspects other than impact of pulp rheological behaviour can interfere with each other in their contributions to how they affect the sub-processes, effects owing to pulp rheological behaviour have a direct impact on the flotation performance. Subtle increase in pulp viscosity can interfere with sub-processes in flotation leading to decrease in recovery and grade, and it is difficult to assess the effects due to such subtle changes. Reagent based strategies to overcome the problematic aspects has been explored here.

Jan 1, 2014

By Charles J. Haas

The objective of this research was to investigate the interaction phenomena of rock and types of rock bolts to develop design principals for using grouted roof bolts. The investigation was to determine the effectiveness of grouted bolts in resisting lateral displacement and axial separation along fracture planes, and also to determine if grouted bolts eliminate the axial tensile stress near the anchor and the resulting rock fracture. The first year&apos;s effort involved defining the post-tensioning response of grouted bars and determining the amount of shear resistance generated by conventional and resin-grouted bolts. A finite-element analysis showed that if the rock and resin grout behave in an elastic manner, the post tensioning of a grouted bar will affect mine roof stability only if movement occurs near the collar. An experimental shear test program revealed that both conventional bolts and resin-grouted reinforcing bars significantly increase shear resistance along fracture or bedding plane when the average normal compressive stress on that plane is low (in the order of 25 psi) and when the bolt is oriented so that the shear displacement tends to lengthen the bolt. An increase in shear resistance is also noted at the higher normal pressure of 250 psi; however, the increase is small compared to the corresponding shear resistance without a bolt. Conventional bolts oriented so that they tended to loosen with shear displacement added no significant shear resistance.

Jan 1, 1974

By C. R. Copeland

Water sprays are a common method used to reduce particulate matter (PM) emissions. Various factors such as wettability, surface area coverage, fine particle engulfment rates, interparticle adhesion forces, suppressant penetration and suppressant longevity have all been suggested as critical factors in achieving effective PM control. However, it has not been established which of these factors are the most important. Experimental work indicated that suppressant penetration is the most critical of these factors. The length of time after application that suppressants were effective was also improved by using hygroscopic reagents that retained moisture to prevent evaporation. Maximizing suppressant penetration and improving suppressant longevity led to an average 86% reduction in PM10 concentrations in laboratory dust tower tests.

Jan 1, 2008