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By Valerio Viti

In High Pressure Die Casting a molten metal is injected through a thin gate into the cast cavity. High injection pressures and high gate velocities create atomization phenomena which can negatively affect the final quality of the cast. In order to control atomization process it is essential to understand the atomization patterns and the two-phase flowfield that exist at the gate exit. In the present work, 2D numerical simulations of the flow of molten Magnesium through a high aspect-ratio rectangular gate are performed using a water analogue for an open and closed cavity. The numerical simulations made use of VOF-type (Eulerian) physical models and Lagrangian models. Further, a sub-grid scale model was implemented that, in conjunction with VOF-type equations can efficiently predict the general atomization pattern without the need for high-resolution grids. The numerical results were compared to experimental data for validation.

Jan 1, 2006

By Clara María Lamus Molina

The following minerals found in the residual black sands from gold mining in El Bagre Antioquia (Colombia) were identified as having major economic interest: Ilmenite (FeTiO3), with an average of 49% of TiO2, frequently altered presenting crowns; lamellaes of rutile and alteration textures; titanomagnetite with up to 25% of TiO2; magnetite (Fe3O4) in individual grains or associated with others minerals as hematite and ferromagnesian silicates rutile (TiO2) with considerable quantities of Nb2O5(0.1-3.7%Wt); zircon (ZrSiO4) with 66%Wt of ZrO2 and monazite with an average of 63.43%Wt of REE, this frequently associated to xenotime and thorite forming textures as little drops. Analysis in EPMA and SEM/EDS showed percentages of minor elements and traces, thereby clearly establishing the applications of these minerals in diverse industries. Furthermore, a detailed granumetric study of the different minerals and textural relationships among them also allowed for establishing the basis for possible processing and exploitation.

Jan 1, 2006

By Lester G. Rollins

Coal today enjoys a dominant position, serving the energy and metallurgical marketed The measure of success in the market place is, and will continue to be, the price per million BTUs or price per ton delivered to the user. The Coal Industry's remarkable record of price stability since World War II is well known. The next twenty years promise to be equally as challenging. This challenge will be met our president, Mr. Drain, has often stated that, ?The Joy Manufacturing Company is betting that coal will meet the challenge.? To this end, the resources of Joy have been committed to doing its part. Joy's efforts are directed toward a target which has been defined as: 1. Deliver coal to the user at a price of $.15/MBTU or less. or; 2. Deliver coal to the mine portal at a cost of $1.00 or less.

Jan 1, 1966

By G. W. Jones

"INTRODUCTION As part of its work in promoting safety, the Bureau of Mines is investigating various means of eliminating or mitigating the explosion hazards of combustible gases encountered in mining and industry. Information has been obtained and a procedure developed whereby the explosibility of many complex gaseous mixtures may be calculated in a rather simple manner without the necessity of performing laborious laboratory experiments. An earlier publication 3/ described the method of determining by calculation the limits of inflammability of gaseous mixtures, including methane, hydrogen, carbon monoxide, nitrogen, carbon dioxide, and oxygen. The information published in the above report permitted calculation of the limits of inflamnability of such gases as are liberated by mine fires, gases from explosives, automobile exhaust gases, gases present after mine explosions, blast-furnace gas, and other gases of similar type.Gases liberated in certain potash mines in the western part of the United States sometimes contain ethane, in addition to the gases named. An investigation was made to obtain data from which the limits of inflammability of such gaseous mixtures could be determined by calculation. 4/Similar data have been Published covering all types of natural gases containing wide ranges of concentration of nitrogen and carbon dioxide.5/"

Dec 1, 1944

By N. A. Eilertsen

Among the numerous Low-grade manganese deposits in eastern Aroostook County, Maine, the Dudley deposit near Mapleton in the northern district is one of the few known to contain an appreciable tonnage averaging above 10 percent manganese. The ore body, consisting of stratified manganiferous hematitic shale, is over 5,000 feet long and ranges in width from 30 to 175 feet. The deposit was extensively explored during 1942-44 by the Manganese Ore Co., a subsidiary of M. A. Hanna Co. of Cleveland, Ohio. Data obtained from this work were made available to the State and Federal Geological Surveys for estimating ore reserves. An estimate by the Maine Geological Survey, using a 10-percent manganese cutoff and to a depth of 200 feet, shows 609,000 long tons of manganese metal in material averaging 12.6 percent manganese. By lowering the cutoff limit to 5 percent manganese, the estimate was increased to 919,000 long tons of metallic manga¬nese in material averaging, 10.4 percent manganese,

Jan 1, 1957

By Samuel Polinsky, Lawrence W. Bierman, Wayne Perkins

[A column float beneficiation plant using 9, 8.5 foot diameter, cells was constructed by the Simplot Company and the Smoky Canyon Facility in the fall of 1986 and has been in operation since May of 1987. The float beneficiation process was developed jointly by the Simplot Company and the Bureau of Mines (Salt Lake City, Utah) which incorporates the Bureau's bubble generator design and chemistry system based around the reverse float technology, (Albany Bureau of Mines, Application of Carbonate-Silica Flotation Techniques to Western Phosphate Materials, Rule, Dallenbach , Larsen, RI8728, 1982) . This chemistry has been modified by Simplot in both patented and unpatented improvements. The objective of the beneficiation process was to reducethe A1203 content in the overall pipeline concentrate by 0.2 wt z. Therefore, a process stream was identified in the mill circuit which provided an opportunity to isolate and treat 1100 tons per day of poor quality phosphate concentrates The process allows recovery of approximately 15% of the mill concentrates, otherwise unsuitable for fertilizer production. The alternative would have been to waste this ore. Wasting would have resulted in considerable ore loss, increased mining costs and required additional products grinding. ]

Jan 1, 1989

By S. H. Ash

[On December 2, 1932, the Governor of California called upon the representatives of the mining industry of the State to attend a meeting at Sacramento to discuss ways and means of assisting is relieving some of its perplexing and extremely distressing problems, particularly the mounting cost of accidents which faces the industry with an industrial insurance rate for classification of $11.85 per $100 of pay roll, effective January 1, 1033. The significance of this fact is at once apparent when it is realized that the classification rates per $100 of pay roll for mining have steadily increased for some time, as follows: $3.91 in 1924, $5.54 in 1925 and 1926, $8.04 in 1927, $8.53 in 1928, $9.05 in 1929, $9.42 in 1930, $10.54 in 1931, $10.99 in 1952, and $11.85 in 1133. In other words, the cost rates have acre than doubled, wile statistics indicate that the accident rates nave shown an entirely different trend. At the meeting mentioned, one of the management officials sounded an effective keynote when he declared that a spade should be called: a spade. The perplexing problems of any industry can be approached best and remedies applied if that policy is kept to the front. It is appropriate to mention that high accident rates and a decrease in wages in recent years have unquestionably accounted in part for a unit cost rate, on a pay-roll basis; it also is well to explain that the policy years3 1926 to 1930, inclusive, are the years on which the accident-cost experience for 193: is based. That accident rates :lave not undergone the expected beneficial chance in California's experience is apparent in the words of a Bureau of Mines report:4]

Jan 1, 1933

By Rolland L. Blake

The Bureau of Mines investigated the mineralogy, tonnage, and beneficiating characteristics of oxidized (nonmagnetic) taconite iron resources of the Western Mesabi Range as part of its program to insure adequate future domestic mineral supplies. Magnetic taconite currently provides about 95 pct of Mesabi production, but the large tonnages of oxidized taconite between the magnetic deposits will be needed to help meet future domestic demand for iron ore. Three bulk samples that represent large tonnages from the Western Mesabi Range were selected to determine their mineral composition and liberation by light optical microscopy and to test their beneficiating response. This report describes the mineralogy and liberation characteristics of the three samples of the Biwabik Iron-Formation for 26.5 mi (42.7 kID) from Keewatin to Grand Rapids, MN. (Details of response to beneficia-tion were reported previously.) The samples represent mostly material from the Lower Cherty Member of the Biwabik-Iron Formation, although one sample included some Upper Cherty Member. Minerals of all three samples were quartz (chert), hematite, goethite, and minor to trace amounts of magnetite, iron carbonate, and iron silicates. It was concluded that the oxidized taconites of the Western Mesabi Range represent a subeconomic indicated resource that can be selectively mined and beneficiated as a future large source of iron feed for steelmaking.

Jan 1, 1983

By James W. Townsend

[The Harrington-Hickory mine in the Star raining district, Beaver County, Utah, has produced approximately 20,000 tons of lead-zinc-silver ores since 1910. Production previous to 1910 is not known. The mine is owned by the New Majestic Mining Co. The property was rehabilitated and operated by James D. Williams under a 10-year lease with option to purchase from April 1943 to May 1949, Loans from the Reconstruction Finance Corporation in the aggregate of $41,000 wore used in construction of an access road, rehabilitation of the mine, and purchase of equipment for full-scale operation. The improved, all-weather access road extends from loading ramps on the Union Pacific Railroad at Milord to the urine storage bins 5 miles west o f town. The mine is serviced electrically by a. 5,000-volt line owned by Telluride Power Co. Mine transformers step the voltage down to 440/220/110 for surface and underground service.]

Jan 1, 1953

By John A. Church

Jan 1, 1903

By D. L. Leach

This report covers laboratory experiments simulating in situ copper recovery from primary sulfide ores in sulfuric acid systems pressurized with oxygen. Copper extraction and acid consumption data are correlated with temperature in the range 50-150°C and quenched pH in the range 0.25-2. Adverse changes in the chemical composition of the leach solution and the formation of gangue-mineral alteration products and secondary sulfides can severely limit the extraction of copper above 90°C. Keeping the pH below the self-buffered value of about 2 and the temperature below about 110°C produces the maximum extraction rates. Forcing the pH too low not only results in excessively high acid consumption but may also limit the extraction of copper at temperatures above 100°C.

Jan 1, 1975

Of the many organic impurities present in Bayer liquor, sodium oxalate is known to have one of the most detrimental effects on the Bayer process. Because of its limited solubility, it will co-precipitate with gibbsite during the precipitation stage which results in many operational challenges for the refinery. Despite the importance of this phenomenon, the interaction mechanism between gibbsite and sodium oxalate is not well understood. In this study, the growth of sodium oxalate on three main morphologies (random agglomerates, prims and hexagons) of water-washed and caustic-washed gibbsite was observed under synthetic Bayer conditions using in situ optical microscopy. After a short induction period, oxalate started to nucleate on gibbsite crystals, and grew with a needle-shaped morphology which eventually developed into oxalate bundles. In addition, the results indicated that caustic washing was able to partly decompose gibbsite crystals and thus make the gibbsite surface rougher, which provides more potential sites for oxalate nucleation and growth. The growth rate of oxalate crystals on the basal (001) face of water-washed gibbsite was 1.33 µm/min determined by the time-lapse imaging of in situ optical microscope.

Jan 1, 2014

By S. E. Burton

The White Rock area of the Boiling Springs manganese-iron deposits comprises about 3,200 acres of land in Monroe Township, Cumberland County, Pa. (See fig. 1.) This property was brought to the: attention of the Bureau of Mines by Pennsylvania Geological Survey Bulletin 128, entitled "Manganese Ores of Pennsylvania" by R. M. Foose. It was examined by an engineer of the Bureau of Mines in August 1942 and was further investigated by the Bureau by churn drilling and underground development during the period December 1942 to February 1944. Beneficiation tests were made on samples of the ore. This report describes the work done during the investigation and presents the results obtained.

Jan 1, 1949

By Maurice J. Peterson

THE VISUAL-ARC spectroscopic method of rapid qualitative analysis of complex inorganic compounds has been popularized in the past few years and is being employed by an increasing number of laboratories. The mineralogy and chemistry departments of several universities recently have added visual spectroscopy to their laboratory curricula. This revival of interest in a somewhat dormant analytical method has been stimulated through the publication of three papers 4 by members of the College Park staff of the Bureau of Mines. These virtually are the only recent sources of information on visual-arc spectroscopic analysis. They include data on the spectroscopic assembly, the analytical procedure, and the practical application of the method to determinative mineralogy and related fields. Requests for reprints of these papers continue to be received; at present only a limited number of copies are available for distribution. In order that these requests may be adequately answered, material from the three papers has been combined and, with some additional data, is presented in this bulletin. Numerous specific inquiries have been received regarding types of equipment available, problems in instrumentation, and information on the approximate sensitivity limits of the elements that can be detected by this method. Some of this material was not included in the original papers. Accordingly, the table of wavelengths has been revised to include the approximate visual-arc spectroscopic sensitivities, and a section on commercially available equipment has been added.

Jan 1, 1953

By Robert W. Row

The run-of-mine coals in the U.S. being fed to coal cleaning plants have become increasingly finer due to the adoption of modern, mechanized mining methods, and economics are dictating that finer fractions, as well as the coarser fractions, be cleaned. Traditional dewatering methods (vacuum disc filters and centrifuges) are proving inadequate for preparing fine refuse for disposal or fine coal product for downstream handling. The Electric Power Research Institute has been supporting research into the nature and limitations of mechanical dewatering, and novel ways of improving it. The efficiency of various silicone-based chemicals at aiding dewatering was investigated, and it was shown that the final moisture content of hydrophilic coals after vacuum Filtration could be reduced by 1 to 5% with up to 40% increase in filtration rate by addition of one of several of these silicones. EPRI also has an on-going program at its Coal Cleaning Test Facility to investigate the performance of the Larox pressure filter in comparison with that of the disc filter and solid bowl centrifuge. While improvements to the dewatering performance currently being obtained in existing operating plants by such means are achieveable, a fundamental study has shown that, regardless of changes in operating conditions, there may be a limit to the lowest cake moisture content attainable by mechanical dewatering of a given sample of coal fines. Determination of this limit for a specific coal would be useful in designing facilities to dry and handle it.

Jan 1, 1984

A belt of serpentinized ultrabasic rocks intrudes a moderately folded geosynclinal sequence of fine to coarse sediments, acid, intermediate, and basic volcanics as well as a batholithic mass of granitic rocks. The ultrabasic body contains small included masses of melanocratic and leucocratic rocks, together with chromium, copper, zinc, and nickel mineralization.

Jan 1, 1969

By W. P. Yant, H. C. Fowler

"INTRODUCTIONHydrogen sulphide is probably the most toxic gas associated with crude oil. Hydrocarbon (petroleum) vapors themselves are harmful to the human system, but hydrogen sulphide, when present, is usually more important from the standpoint of health and safety. These conclusions were reached in an investigation of the toxic gases encountered in the transportation end refining of high-sulphur petroleum. The results of that investigation are presented in Bureau of Mines Bulletin 23l. although the writers of Bulletin 231 paid no direct attention to the production of oil in the field, they attributed to hydrogen sulphide reports of accidents caused by gas in the oil fields of Mexico.During the development of oil fields in Texas, a ""poison gas"" was encountered that constituted a decided health and safety hazard. The present report discusses an investigation of this gas made in July, 1926.The major portion of the investigation was conducted in the Panhandle field of Texas, but the study also includes the Big Lake and McCamey fields.Scope of WorkThe work undertaken in each field included:Examination of the gas-coming from representative wells at various locations in the field; also analyses of the gas-air mixtures to which the workmen were or might be exposed.Observation of symptoms of poisoning and severity of these symptoms."

Oct 1, 1926

By D. C. Cooper, P. M. Green, J. A. Plant, P. R. Simpson, A. J. Reedman

Paper presented at the 28th International Geological Congress held in Washington DC, July 1989 (International geochemical mapping sessions). The Grampian Highlands and English Lake District evolved as part of the American and European continental plates, respectively, and were separated by the Iapetus Ocean until they were tectonically juxtaposed during the late stages of the Caledonian orogeny. The similarity in the controls of the distribution of gold pathfinder elements and gold mineralisation in the two regions thus provides important information for understanding the genesis of gold deposits in comparable tectonic settings elsewhere. The data presented are inconsistent with models that invoke a juvenile source of gold or its pathfinder elements. Instead, they support a model whereby gold and its pathfinders were initially concentrated in volcano-sedimentary sequences in rapidly subsiding, tectonically controlled basins and in associated volcanic rocks. Remobilisation and mineralisation occurred subsequently, probably as a result of an increase in oxygen fugacity associated with the influx of granite magmas into the crust and the establishment of hydrothermal convective circulation systems

Jul 1, 1991

By Rudolph K. Hoagberg

Silica sands, primarily in coarse size ranges, are used to prop open fissures or voids created in the bedrock by hydraulic fracturing. This procedure increases the flow of gas or oil or other fluids through the bedrock. The sands used must meet various specifications relating to their physical and chemical characteristics; these characteristics are in turn related to the geologic provenance of the sand deposit. The Jordan Sandstone, a Cambrian formation which is exposed in Minnesota and Wisconsin, meets the specifications of a proppant sand by virtue of its depositional history and its sedimentary properties.

Jan 1, 1980

By T. A. Rickard

An educated man is distinguished neither by his clothes nor by his knowledge; he is replarkable not for the things he says, but for the way he says them. You cannot even stand with him under an archway in the rain without finding him out. He may talk only of the weather. His words and his phrases alike may be simple. -at distinguishes him is the arrange- ment of his words; however desultory his talk, it will be method- ical; he has habituated himself to foreseeing the part to be played by each word he uses and the place to be taken by each sentence he utters. On the other hand, the uneducated man, though shrewd and well-informed, will relate facts and events as they recur to him, generally in disorder; in his effort to recollect and in his attempt to rectify forgetfulness he will pause irregularly, filling the intervals with meaningless phrases, such as "and then ", "and: so ", or 'said he to me", "said I to him"; and even the contipuous parts of his story will be told confusedly-because he has not learned the proper use of words.* My own experience as an editor of technical manuscripts has taught me that the misuse of 'that' and 'which' is a fruitful cause of obscurity and confusion. The relative pronouns have distinct functions, and no writer can express himself clearly until he has learned to discriminate between these I functions. For example:

Jan 1, 1931