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By C. S. Smith, K. K. Ikeuye

In an earlier paper1 one of the authors called attention to the significance of the relative free energies of grain boundaries and interphase boundaries in alloys in determining the shape and distribution of micro-constituents. The ratio of the interphase and inter-crystalline boundary energies (that is, —?12, where ?12 is the energy of the interface between a crystal of phase 1 and a crystal of phase 2, and ?11 is the energy of the boundary between two crystals of phase 1) will be denoted by F. It is this ratio that determines, by the simple triangle of forces relation, the dihedral angle, ?, of phase 2 where it adjoins a boundary between two grains of phase 1. On a metallographic sample various angles are actually obtained because of the random orientation of the plane of observation, but the statistically most frequent angle is the true one. These basic principles were discussed in detail in the earlier paper. The experiments described below show the effect of both composition and temperature on ? and T for some alloys containing a liquid phase, and provide data on the rate of approach to the equilibrium angles in both solid and liquid phases. All the alloys were melted in a graphite crucible and cast into ingots 3/4 by 11/8 in. cross-section. Some of the aluminum alloys consisted of two immiscible liquids from which uniform castings could not be obtained. The amount of liquid phase varied locally to a considerable extent and the analyses were meaningless. Nevertheless, the composition of the liquid would not differ from that in an alloy of the intended gross composition, and the synthetic composition of the alloys was therefore used in considering the surface energy results. The ingots were given initial deformation by cold-rolling to 50 pct reduction, annealed, and given a second 50 pct reduction prior to cutting into small samples for heat treatment at the times and temperatures subsequently reported. The resulting micro-samples were carefully prepared metallographically and examined at magnifications of 650, 1280, or 2500. The objectives used were 21X, 0.40 NA (dry); 41X, 0.65 NA (dry); and 80X, 1.40 NA (oil emulsion). The appropriate angles were measured by rotation of the stage of a Bausch and Lomb metallograph to align the appropriate boundaries successively with a cross-hair in a micrometer eyepiece. About 250 angles were measured on each phase. Though the angles were read to 1°, the accuracy is probably not above 3°, because of uncertainty in setting the cross-hair tangent to the sometimes curved boundary. The corners of very small particles, particularly in early stages of adjustment after cold-rolling, were difficult to measure and the results were slightly dependent on the magnification used (compare Fig 1-C and 1-D). With particles of larger size and more nearly equilibrium shape, magnification made no difference (vide Fig 1-F and 1-G). The measured angles were grouped in 10° intervals (5° if ? was less than 20°) and plotted in bar

Jan 1, 1950

By E. O. Wagner, V. F. Parry

This paper summarizes investigations during 1949 on three pilot plants for drying low-rank fine coal by entrapment in hot gases. Detailed operating results on processing seven coals having moisture ranging from 24 to 62 pet, formulas and data for calculating performance of large units, and general conclusions on the problem of drying fine coal are presented. THIS paper presents a summary of investigations by the Coal Branch of the Bureau of Mines during 1949 on the removal of internal moisture from low-rank coals by processing them in the entrained and fluidized state. A paper on this subject, giving a summary of the early work, was presented at the 1949 AIME annual meeting1 and gave a the- oretical discussion of the time and heat required to dry various sizes of low-rank coal. The investigations on two pilot plants were presented in the foregoing paper. During 1949, three additional pilot plants were built to study phases of the drying problem and to investigate different techniques of handling fine coal in the entrained and fluidized state. The present paper gives operating data on the new units and presents detailed data on the drying of seven coals having bed moisture ranging from 62 to 24 pct. The problem of removing surface moisture from fine coal is principally one of heat exchange and dispersion of the coal particles so that heat can reach the liquid moisture to permit evaporation, and it does not involve the factors of size and time of contact to any great extent. If enough heat can reach the surface of the particles at temperatures higher than 250°F, moisture evaporates almost instantly, and the factors of time and size are of secondary importance compared with the factors of heat balance and dispersion of the coal. Therefore, it does not appear to be necessary to employ a fluidized bed when removing surface moisture, and the most efficient process would be one in which the coal particles are entrained in a hot gas stream of optimum temperature traveling at a velocity that causes the particles to disperse into a low-density phase. When low-rank coals are dried, the fluidized bed is necessary to provide control of time of contact. This is done by adjusting the superficial velocity which controls the density or dispersion of the particles. The density of beds having fluidized properties suitable for drying low-rank coals appears to range from about 5 up to about 15 lb per cu ft. When the density is below 5 lb per cu ft, which represents a low-density phase, optimum conditions for removal of surface moisture should be found, and this requires superficial velocities of about 15 fps. The problem of removing bed moisture from low-rank coals involves consideration of size of coal, temperature, mass flow, heat balance, pressure, time of contact, and method of dispersing the coal in the heating mediums. The experimental work presented here gives data on these factors. Coal sizes up to 1/2 in. x 0 were dried with hot gases having initial temperatures ranging from 1900° to 2400°F. Coal

Jan 1, 1951

By J. D. Morgan

Introduction In 1987, the US economy continued to grow steadily, reaching an annual rate of $4.6 trillion in the last quarter. The value of domestically processed mineralbased materials rose slightly to $250 billion. The value of US metals rose sharply to more than $7 billion. Industrial minerals rose slightly to $18 billion recycled scrap was valued at $4 billion. Metal prices rose sharply toward year-end. A number of mining and metal companies experienced increased profitability, fostering more optimism about the future. Consumer demand strongly affects mining because the US economy is relatively saturated with long-lived products. Consumer, mortgage, and federal debt continue to rise. 244 million citizens already possess 170 million licensed motor vehicles and 100 million dwelling units. New car production fell 9% to 7.1 million units, but truck and bus production rose 9% to 3.8 million units. New housing starts fell 10% to 1.6 million units. Excess productive capacity exists not only in the US, but also in many other countries. Consequently, the US mineral industry is encountering stiff competition from others, as well as increasing competition from newer engi¬neered materials. Domestic production of plastics rose 9% to 25 Mt (27 million st) - on a volume basis, double all metals. Some 7% of petroleum goes to make petrochemicals including plastics. Imports of nonfuel mineral-based materials in 1987 were valued at $37 billion and exports at $24 billion. Imports supplied a significant proportion of total US consumption of several important mineral materials, including many classified as strategic and critical. In December, the Congress mandated that any major changes in stockpile goals be made only by law, and that the Department of Defense submit annually detailed stockpile supply/demand analyses. Concern about apartheid in South Africa continued, resulting in increasing interest about chromium, manganese, platinum-group metals, cobalt, vanadium, and gold. The National Critical Materials Council continued to monitor the US materials position. The Defense Production Act, authorizing priorities and allocations, supply expansions, voluntary agreements, and the National Defense Executive Reserve continues in effect through Sept. 30, 1989. Under the DPA, the US Bureau of Mines maintains the Emergency Minerals Administration. Further consultations were held with Canada to strengthen the North American defense industrial base. Coal production, 60% from open pits, rose 2% to 825 Mt (910 million st) valued at $21 billion. Nearly four-fifths was burned to generate 56% of US electricity. Exports included 42 Mt (51 million st) of metallurgical coal and 24 Mt (27 million st) of steam coal, with a total value of $3.3 billion. Domestic petroleum production fell 5% to 480 Mm' (3 billion bbl). Uranium mining, including recovery from phosphates, fell 4% to 5.9 kt (6500 st). Nonfuel minerals Major metals: Raw steel production - a major consumer of many minerals - rose 7% to 79 Mt (87 million st). Domestic iron ore production rose 11% to 44 Mt (48 million st), about 96% pelletized. Net imports, though, fell 8% to 11 Mt (10 million st). Raw steelmaking capacity fell 6% to 102 Mt (112 mil-

Jan 5, 1988

By John T. Galey

A combination of two factors in addition to the current Federal drilling and price regulations reduced by 120 from I942 the number of new wells completed in southwestern Pennsylvania during the year. No new prospective area was found comparable to the Armbrust gas pool, Westmoreland Co., which accounted for a seventh of the last year's drilling, and it is considered doubtful whether, even if such a field had been discovered, the drilling contractors, who have been seriously affected by the manpower shortage, could have drilled many more wells than they did during the year. New wells totaling 445 were completed for a combined footage of over 1,250,000 Dry holes numbered 131 and had a footage of nearly 400,000. Old wells drilled deeper total 55, of which 17 were found nonproductive. Shallow Development Oil Oil completions yielded an initial of only slightly over one hundred barrels from 21 wells for about the same per well average as that of a year ago. However, 65 bbl. of this total came from two wells in two new strikes. The footage drilled of nearly 33,000 gives an average of nearly I00 ft. less per well than a year ago. Two old wells drilled deeper had a combined initial of only 4 bbl. The largest oil well of the year, 40 bbl., was found in the Speechley (U. Dev.) sand at a depth of 3492 ft. in German township, Fayette County. The location is several miles east of the nearest oil production hut as the area that could be occupied by a pool is fairly well delimited by drilling, the extent of this production would not appear to be large. The other notable oil production was found in the Dunkard (Penna.) sand, Cumberland township, Greene County, at a depth of 1065 ft. Here the first well had an initial of g bbl. and the second 25 bbl. However, a third proved dry, and as this area is also delimited by drilling, the pool doubtless will be of small area. Gas Gas completions yielded an initial of slightly over one hundred million cubic feet per day and new wells, totaling 303, account for all but four million of this volume. Old wells drilled deeper, numbering 35, found gas. The per well average in new drilling of approximately 320 M cu. ft. is nearly 165 M cu. ft. less than a year ago and the total footage is slightly over 830,000, which is about a quarter of a million feet less than in 1942. Average rock pressure of new completions is approximately 365 lb. per sq. in. The entire volume of new production is from the Upper Devonian or higher stratigraphic horizons. In Allegheny County, the grestest activity was in Forward and Plum townships. Wells there account for more than one half the completions. One large well was drilled in Forward township and an open flow of 3.623 million cubic feet was found in an old Gantz (U. Dev.) sand area. The top of the sand was encountered

Jan 1, 1944

By T. D. Tiemann

The extraction of iron oxide from several types of siliceous iron ore by digestion in sulfuric acid solutions was investigated in the temperature range from 80 to 258°F at concentrations from 10-60% H2SO4. Degree and rate of extraction were found to be critical with respect to both temperature and acid concentration, requiring temperatures in excess of 250° F and acid concentrations of 50% to effect 80-90% extraction of iron oxide in 60 min. Rate of extraction is directly related to surface area and apparently controlled by the rate of chemical reaction. The activation energy was found to be approximately 25,000 cal per g mol. Extraction characteristics of the several ores were found to be similar. The Department of Minerals and Metals Engineering at the University of Wisconsin conducts a continuing research program to develop processes for the utilization of low-grade iron ore deposits such as the nonmagnetic taconites of the Wisconsin Gogebic range. Methods under study include high-intensity magnetic and high-tension electrical concentration, flotation, direct reduction and chemical extraction. Concentration of a number of low-grade siliceous iron ores by the extraction of silica in sodium hydroxide solutions has been reported by the writer and others in the literature.1,2,3,4 Residual concentrates containing as much as 65% iron have been obtained from taconites containing less than 30%. Currently an alternative approach is under study, namely the dissolution of iron oxides from siliceous gangue by extraction in acid, with subsequent recovery of the iron from solution. Such a process for extracting iron oxide from the low-grade oclitic deposits of Alberta with hydrochloric acid was investigated and described by Gravenor, Govett and Rigg.5 The current investigation, which is entirely devoted to extraction with sulfuric acid, is the subject of this paper. In part, the objective of this research was to determine the possibility of leaching iron ores in situ with sulfuric acid. The investigation of a recovery method is left to later research. The ores investigated contained hematite (Fe2O3) as the principal iron-bearing mineral and minor amounts of goethite (Fe2O3 .H2O), magnetite (Fe3O4), and iron-bearing silicates. The gangue was essentially quartz occurring as single crystals and microcrystalline aggregates. Detailed description of the ores may be found in the literature.1,2,4,6 A comparison of the specific ores used in this investigation is shown in the partial analyses of Table I. EXPERIMENTAL METHODS All extractions were made at atmospheric pressure using beakers with a mechanical stirrer for those tests run below the boiling point, and Erlenmeyer flasks for those at the boiling point. A thermostatically controlled hot plate was used for heating, and this maintained the mean temperature within the solution to within ±3°F during extraction. The sample of ore for extraction was weighed to + 0.02 g. For tests below the boiling point, the sample was added to the beaker containing the sulfuric acid solution at the desired temperature. For the boiling-point tests, the sample was added to the Erlenmeyer flask followed by distilled water and the

Jan 1, 1968

By A. Lee Barrett

MINE power systems are quite different in many respects from those usually found in industrial plants. Wide areas are served, usually by a circuit which is connected continuously throughout the mine. In some mines one circuit may run for several miles. There are usually a small number of branch circuits involved considering the areas covered. In all mines circuits are sectionalized at approximately 2500 ft by means of switches. All, or at least most branch circuits, are sectionalized by manual switches. In some mines automatic sectionalizing gear is used to give automatic overload protection at various strategic points in the system. However at the present time this practice is by no means general. Circuit hazards in mine electric systems are much greater than those encountered in industrial installation. Falls of roof or coal form a prominent hazard which may break the wire and may cause ground faults or partial ground faults. Ordinarily electric cables in mines cannot be insulated, there- fore n fall can easily cause a short circuit. The humidity in most mines is greater than 95 pct and at many points the floor is wet and water may be dripping from the roof over insulators, increasing the difficulties at that point. All electrical circuits must be contained in the mine entries and space must also be provided for moving equipment and men. Consequently, because of the proximity of the power circuit to the locomotives and other moving equipment a considerable hazard is introduced. Mine haulage track is not always good so that wrecks are not unusual. A wreck frequently does consider- able damage to the power circuit. A ground fault frequently results in heavy arcing which may be sustained. If the damage to the circuit is mechanical it may mean that a trip of coal has wrecked and a great deal of coal dust could be thrown into the air as a result of the wreck. The arc resulting from the ground fault could ignite the coal dust and a mine explosion would result. A continued ground fault, even if high in resistance, also may ignite the coal which may be on the bottom of the entry and a mine fire may result. The fire hazard is one of the most serious hazards in any coal mine. Since the mine circuit is completely interconnected, any power interruption resulting from a fault seriously affects the whole operation. Unless the mine is completely sectionalized the whole mine will be shut down until the fault is located and the proper switches are opened to isolate the fault; even then large areas may still be without power if they are supplied by a single power circuit which may be opened in isolating the fault. Further, mine power is usually supplied from a relatively small number of substations and the fault may be on a stub feed circuit, in which case power cannot be restored until the fault has been cleared. Practice varies widely with respect to placement of substations. Usually they will be spaced from I to 2 miles in 500V operations, and at 1 mile intervals or less, in 250 V operation. Actual mining operations govern substation placements and no general rules can be followed.

Jan 1, 1948

By D. A. Stout

The Rouse Mine, belonging to the Colorado Fuel & Iron Company, earlier known as the Santa Clara Mine, is located at Rouse, Huerfano County, Colorado. Operations at this property started about the year 1899, after the old Rouse mine had been drowned out by a large flow of water coming from the strata underlying the Cameron seam. The present new Rouse mine was opened by a slope on what is familiarly known as the Walsen seam in the Walsenburg district. This slope has an average grade of 12 per cent bearing approximately, south 45 degrees west, and having at the present time a total length of 6300 feet. This seam has an average thickness at that property of five and one-half feet; however, there are sections of the mine where the thickness is from seven to eight feet. The mine has been developed. since the time it was opened on what is known as the Room and Pillar system ; water level entries have been driven right and left off the slope, and in some cases the rooms are driven directly up the pitch; and in other cases entries have been driven with rooms turned on water level courses. The first flow of water of which we have ally record was encountered in 1901 in what was called the "Second West Entry." This flow, however, was small, and did not require the installation of any large pump unit. From 1901 up until 1909 the flow increased normally as the field was developed. In January, 1909, the first large inflow occurred, coming from a break in the seventh west entry, making a total flow at that time of about 500 gallons per minute. This necessitated putting in larger pumps, and the first pump to be installed of the centrifugal type was a 600 gallon Worthington. By the year 1911 the water had increased, due to additional development, until it was found necessary to install an additional 600 gallon Worthington centrifugal type pump. In December, 1912, a break occurred in the eighth west entry, between the fourth and sixth cross entries, making 2000 gallons per minute. This flow decreased after a period of three weeks some 500 gallons, but on account of the quantity of water then being handled at the mine, and in view of the fact that we needed some reserve pumping equipment to take care of these flows, and additional 600-gallon Worthington centrifugal type pump was installed in June, 1913. An the latter part of 1914 a 250 gallon Reese roturbo was installed to take care of the water, which was being made in the lower workings of the slope. We found after the installation of the centrifugal pumps that the water decreased to a certain degree in the uppermost workings. This led us to believe that the field was being drained, more or less, and the head reduced ; however, our ideas in regard to this were again upset in December, 1915, when we encountered a flow in room 6 off the first cross entry on the ninth east entry. This flow was not as large as previous flows had been, but made 200 gallons per minute.

Jan 1, 1921

By Paul J. Bennett, James E. Castle

The kyanite minerals, including kyanite, silimanite, and andalusite, are anhydrous aluminum silicates with the formula Al2O3SiO2. lumortierite and topaz are also included in this group because they are closely allied in composition and thermal behavior. However, leither are mined commercially today. They ire typical metamorphic minerals which are found in metamorphic rocks on every continent. Kyanite minerals are prized chiefly for their refractoriness and are important components in a broad range of acid refractory products, especially in mortars and castables. World production of kyanite minerals is currently about 250,000 tpy and has been increasing at the rate of 3 to 8% a year for many {ears (Anon, 1972). While kyanite minerals lave widespread occurrence, the consumption of kyanite minerals is concentrated in the relatively few highly industrialized areas where refractories are manufactured, and which in turn are typically close to the major iron and steel producing regions of the world. Thus northern Europe, England, the United States, and Japan are the principal consumers of refractories and kyanite minerals. Of these countries only the U.S. is a significant producer. The largest use for domestic kyanite, both raw and calcined, is in the manufacture of refractory mortars, cements, castables, and plastic ramming mixes. In these applications kyanite constitutes from 10 to 40% of the mixture, the balance being refractory clays and coarser grog materials. A certain proportion of raw kyanite is used to offset the shrinking of the clay binder, whereas the calcined kyanite is used in the coarser sizes for body. Certain high grade refractory shapes and kiln furniture are composed chiefly of graded sizes of calcined kyanite bonded with a little ball clay. In most applications, however, kyanite is used only to fortify the mix or as a minor ingredient. Some manufacturers of mullite brick use domestic calcined kyanite for the fine-grained portion of the brick, but seldom in quantities exceeding 10% by weight. Kyanite is used by ceramic manufacturers of wall tile and sanitary ware to offset shrinkage and cracking after firing. Indian kyanite has traditionally been used to make the coarse grog sizes needed for the manufacture of mullite brick, and for the grog portions of mortar, cement, and castable mixes. It has been largely replaced, however, by synthetic mullite, high fired flint, and diaspore clay or calcined bauxite for other applications. Indian kyanite is available in lump as well as in granules and concentrates, as are sillimanite materials from India and South Africa. Andalusite is available as 8 mesh granules and as fines with chemical analyses not unlike those of domestic kyanites. From time to time and from place to place minor amounts of other aluminum silicate minerals such as dumortier- ite, topaz, and pyrophyllite have been made available at various prices and specifications, but have not been significant factors in the refractory industry. A mixture of kyanite and sillimanite of relatively fine grain-size and of low iron content was at one time offered to the molding sand industry by the Du Pont Co. as a byproduct from their deposits of heavy

Jan 1, 1975

By V. B. Dale

This is one of a series of reports covering the mineral resources of the Nation. It describes briefly most of the known tungsten deposits in Yuma, Maricopa, Pinal, and Graham Counties, Ariz. Most of those described were examined by the author. An effort was made to determine the position of the various deposits by section, township, and range and to give accurate road direction to each property from a prominent landmark. All available maps have been used in making these determinations, but in unsurveyed areas it was necessary to make approximate projections of subdivisions. The township and range numbers refer to the Gila and Salt River base and meridian.

Jan 1, 1959

By B. J. Moore

This publication contains analyses and related source data for 191 natural gas samples from 22 states and 1 foreign country. Of the total samples, 182 were collected during calendar year 1987. The remainder were collected earlier, but releases granting permission to publish were not received before 1987. All samples were obtained and analyzed as part of Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free market economies. This survey has been conducted since 1917. The analyses published herein were made by mass spectrometer and chromatograph.

Jan 1, 1988

Case studies from four western states are used to illustrate the impact of the environmental compliance process on the mining industry. The case studies were not chosen as a statistically significant sample of all mining operations in the western United States but were chosen as representative of operations on both public and private lands and in locations that exhibited varying degrees of involvement by governmental units, non-governmental organizations and the general public. Basically, each case study was chosen because some aspect of their environmental compliance process helped to illustrate an interesting point in the regulatory process. The criteria used to select the case studies were: mines located in different jurisdictional areas, mines located in varying geological areas~ mines located in areas having different historical relationships with mining: and operations that are in production as well as those seeking an operating permit. The variety of such projects should provide the necessary foundation to evaluate the impacts of the environmental compliance process in each location.

Jan 1, 1994

By A. L. Engel

In previous reports5/ of ore-testing studies, teats made by established methods on typical ores selected as representative of certain mining districts have been described in considerable detail. In addition to established test procedures, such as screen analysis, Chemical analyses, microscopical examination of ores and products, sink-and-float separation, gravity concentration, floatation, and magnetic separation with or without roasting, it was sometimes necessary to apply other methods, such as leaching, in instances where physical separations were not feasible.

Jan 1, 1940

By L. C. IlsLey

From time to time the Bureau of Mines has issued publications dealing with the various classes of explosion-proof mining machinery that have been tested and approved as permissible for use in mines having atmospheres that may become inflammable by reason of the inadvertent presence of gas or dust. These publications are confined almost entirely to description of the features contributing directly or indirectly to the prevention of explosion or shock hazards, and are intended to give inspectors, safety engineers, and others already familiar with the general safety requirements more detailed information on the safety features of the design of a particular machine. As a background for papers describing permissible machines and to avoid the necessity of duplicating descriptions of methods of conducting investigations and tests of such machinery, Bureau of Mines Bulletin 305, Inspection and Testing of Mine-Type Electrical Equipment for Permissibility, was pub¬lished in 1929. Three bulletins giving detailed descriptions of the three most numerous types of machines have been issued, viz., Bulletin 313, Permissible Storage-Battery Locomotive and Power Trucks. Bulletin 343, Permissible Coal-Handling Equipment. Bulletin 392, Permissible Coal-Cutting Equipment.

Jan 1, 1937

By J. P. Morris, J. T. Novak, E. A. Sarver

"A variety of reagents are utilized in coal preparation, but aside from performing their desired function relatively little is known about the behavior of these reagents within the processing circuits. Where exactly do reagents go once dosed? In this paper, we present preliminary results of partitioning studies on frother (i.e., MIBC) and collector (i.e., diesel) chemicals commonly used in coal flotation, and examine implications for water management (e.g., in closed-loop systems). Additionally, we discuss the usefulness of such data in predicting environmental transport and fate of chemicals – which is currently a top priority for industry.INTRODUCTIONThe purpose of coal preparation is to upgrade mined coal into more valuable products. Since coal is primarily used as a fuel source for electricity generation, product specifications are typically contracted to minimize unwanted constituents that detract from the overall heat value (e.g., ash and moisture) or that add to environmental pollution or other problems like corrosion at a power plant (e.g., sulfur) (Pitt & Millward, 1979). Failure to meet specifications results in a financial penalty for the coal producer (Szwilski, 1986), and thus preparation processes have evolved to simultaneously optimize recovery of valuable “clean” coal with rejection of mineral matter and moisture. In addition to advancements in equipment and circuitry, development and application of various chemical reagents has dramatically improved the performance of coal preparation processes.Contemporary preparation plants typically include multiple circuits that can be categorized by the size of particles they process: coarse, intermediate, and fine/ultra-fine (Figure 1). Coarse and intermediate circuits generally rely on size classification and gravity separations (e.g., dense-media cyclones), and do not require significant chemical reagents. However, fine and ultra-fine circuits often use froth flotation to separate coal from impurities, which requires chemical additives (Table 1). The primary additives include collectors, which coat the surface of the coal particles to render them (more) hydrophobic and thus more likely to attach to air bubbles and float; and frothers, which aid in the formation and stability of the froth that will accumulate the floated coal particles. Modifiers are also commonly added to flotation circuits to regulate pH in instances where coal or impurity characteristics may change water chemistries (Laskowski, 2001). Following flotation, coagulants and flocculants are often utilized in solid-liquid separations (i.e., dewatering or clarification) for coal products, and for tailings slurries prior to their disposal in impoundments. Coagulants function via double-layer compression1 to bring colloidal particles together, while flocculants promote bridging between the grouped colloids – and the combined result is enhanced sedimentation (Wills, 2006). Defoaming or anti-foaming agents may also be required to avoid fouling of dewatering operations."

Jan 1, 2012

By C. W. Davis

This report follows the same general scheme as did its predecessors; it begins with a dissertation on some phase of ore-testing, continues with results of investigations of ore-treatment methods and of metallurgically important analytical processes, and concludes with an exposition of tests made by established methods on typical ores selected as representative of certain mining districts. One of the first things that is done after an ore has been received is to look at it under the microscope. Microscopic examination serves as an important complement to chemical analysis in interpreting the percentage composition in terms of minerals. If it has been found difficult to treat an ore, the reasons for this action and indicated methods to overcome the difficulties may be ascertained by testing with a microscope. For example, failures in selective flotation have been traced to intimate mineral association and changes in mineral surfaces through incipient oxidation. The importance of surface stains or tarnishes and the presence of adhering slime particles have been found to be responsible for the difficulty experienced in the treatment of certain gold ores.

Jan 1, 1938

By C. W. Davis

This report follows the same general scheme as did its predecessors; it begins with a dissertation on some phase of ore-testing, continues with results of investigations of ore-treatment methods and of metallurgically important analytical processes, and concludes with an exposition of tests made by established methods on typical ores selected as representative of certain mining districts. One of the first things that is done after an ore has been received is to look at it under the microscope. Microscopic examination serves as an important complement to chemical analysis in interpreting the percentage composition in terms of minerals. If it has been found difficult to treat an ore, the reasons for this action and indicated methods to overcome the difficulties may be ascertainedd by testing with a microscope. For example, failures in selective flotation have been traced to intimate mineral association and changes in mineral surfaces through incipient oxidation. The importance of surface stains or tarnishes and the presence of adhering slime particles have been found to be responsible for the difficulty experienced in the treatment of certain gold ores.

Jan 1, 1938

By O. C. Blade

This report on the properties of motor fuels sold through service stations in the United States was made in accordance with a cooperative agreement between the American Petroleum Institute and the Bureau of Mines of the United States Department of the Interior. By agreement with the American Petroleum Institute, identification of the items is confidential. It presents analytical data for 4,857 samples, representing the products of 103 companies. The samples were collected during June, July, and August 1955. As in previous surveys, the gasolines covered by this survey include those from both large and small suppliers. The data were obtained by laboratories of various refiners, motor manufacturers, and chemical companies and submitted to the Bureau of Mines for compilation. A list of the National Motor Gasoline Survey reports published during the past 10 years is given on page 5.

Jan 1, 1956

[lllc purpabr at thla report Vd, Lu JeLermlnr the health ar1J sdfet?; Nene11Le a octatc?J ultll Lne oar L.t support Ydlll ..up.I,ated lu dltetllative cupPurt svsLem, larrellLty hcle.g uaeJ af the Len,::rat 1, UI.Jlng 11-al tl. .1 a d 1 c L V h S LIdl'. L dal. I -ten- lu L he tt I .. L'., etuJ I e. 11'? L_1,1'1,11 .Jtd.. it, ..urn,at'l core ,LuJICCill JhLdll, an.: ...,La -IL .utia_tel .an LI?r oar of -l: l,.!rl .a..a. Ma terI.I auJ ...11,mc[Ii -ldla,tutcle 11. LI.ac .uwIttIca Welt a, a.. V.alte,, L.. .:Ltail, ..,,L., uI. LuClu,alug) Lelll anci ur devel?puJ I.,r Cul r1 , all. ...~.,rLrI Vt,ILt 1.'ere ~e,1C L? .Lher Gentiaii m111cc t, UL.-rye a Variety o. a rL vyl I pp.1Ca:t..n:. 'a.la IrL ..,_wLeiti, Iapl,.III ,tall ~,..:. IL all, maLertdl c1,arait-erlstIcs, JIRICn,IUIIe. and laden ul1.1 ILc rrgatrelaeuls. ,1 r.? p.'rt .a pro-1Jd, labor rep altrlarnts Jdta and illtlitI ieS tie l,ealtll d?J ,atetV ISSUC ,u-1aled Wit su furl Wall a an, CJl,wttuctSOn, I'aLentiaI appll.at1ou:. Ior support Walt, ,a,. , a, sdV.u,L111 .., u.1 retreating lungval1, single -t r-, roar al,- pi r. [,-+ln, anJ SuhIU..,Ina, Sill] b1OpplllgL ale 1:111neated aid al? e.aIWRac AS Sddemcni LV pre,C'IIL..: .,f LI. Clabllhty r+t rlul,I.,y111I? ulg4,rt .I Le.l,lwlug,. Lr i,,,rCASC Lllc rtCVLLrS rat, u., retrc.+tlnp .unui.,11? ur L., elply, A d v Ctnp IuI-,wall in uer;-!y iy1ng seam, . 11111.a1L .a1,.'iI1.-I,.. nr S.IU1tIVlil a1 milItlI; Lust, La LIldnt;2S L.~ gey support Vait Id tdmcLera la dlaa presents,.]

Jan 1, 1980

By G. E. McElroy

The purpose of tins paper is not to present new date on the pressure losses due to bends and chances of area in mine openings through which air flows, but rather to correlate existing data, determined mainly on small duct systems and expressed in a variety of ways, according to uniform methods that facilitate their use in pressure-loss computations. These are required in such, air-flow problems as determining the quantity that will flow through is mine openings under a certain pressure difference or, conversely, the pressure difference that will be required to maintain a certain rate of flow. Air flowing through h ducts, such as mine airways, encounters resistance to flow due to interference of the individual air streams with each other caused by the wall surfaces. The result is that part of the kinetic energy of the flowing stream is converted to heat; and constant renewal of the kinetic energy from the total energy of the flow is required to maintain it. This process manifests itself by a decrease of the total pressure (static pressure plus velocity pressure; of the air in the direction of flow; in order that flow pray occur, there must necessarily be a differences in total pressure between the two cads of the air-ay equivalent to the pressure losses occasioned by the flow, which automatically adjusts itself in magnitude to the pressure difference maintained.

Jan 1, 1932

By G Collecutt, D Proud, D Humphreys

"The hazards associated with dust explosions are well known, and coal dust explosions present a significant hazard in the underground coal mining industry worldwide. In earlier work, we presented computational fluid dynamics (CFD) simulations and test results for coal dust explosions within a 2.5 m diameter circular gallery, along with CFD simulations and test results for the suppression of these explosions with finely atomised water sprays. In this paper, we present refinements to the CFD modelling that yield a significantly improved calibration with the test results, and proceed to investigate by CFD the requirements for suppression of a coal dust explosion in a typical underground roadway. This work was carried out under an ACARP project and we gratefully acknowledge their assistance. CITATION: Proud, D, Collecutt, G and Humphreys, D, 2015. Computational fluid dynamics modelling of coal dust explosions and suppression systems, in Proceedings The Australian Mine Ventilation Conference, pp 309–314 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 31, 2015