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By L. F. Heising

The Bureau of Mines evaluated 191 composites from the central Mesabi Range, Minn., chiefly by reductive roasting and magnetic separation. After reductive roasting and magnetic separation at minus 325 mesh, 28 composites produced concentrates that contained an average of 66.0 percent iron with less than 10 percent silica. Recovery of contained iron was over 90 percent. Natural magnetic material in excess of 5 percent was present in 142 composites. Trial flotation tests were used to evaluate three samples unresponsive to reductive roasting and magnetic separation procedures, and satisfactory concentrates having low silica contents (averaging 6.6 percent) were achieved.

Jan 1, 1965

By B. W. Gandrud

[The Bureau of Mines is conducting an extensive investigation of coal preparation in the Alabama coal fields in cooperation with the University of Alabama coal-mine operators. In this investigation the drainage characteristics of typical coals from the Warrior and Cahaba fields were studied]

Jan 1, 1941

By S. H. Ash

The Pennsylvania anthracite-mining region is the only one in the world of major magnitude. As the deposits of anthracite in the United States are limited virt113.lly to Pennsylvania, the difficulties of this industry have been commonly considered a State rather than a national problem. However, there is also national interest in the conservation and wise utilization of all fuel resources and in the control of interstate waterways. The anthracite industry is confronted with the very se:;-ious :problem of accumu.lation of water in many of the mines. This problem must be solved soon if progressively higr-er mi~ing costs are to be avoided. The water proble~ cannot be solved by the operating compa,nies without State or Federal aid, or both, owing to the magnitude of the work requir~d, diversity of interests of the coal ana surfa.ce ovmerships, hazard to the whole mining community, and interests affec~ed outside the mining region. The cost of abati~ the ever-increasing_surface seepage to mine workings and of handling this seepage once it }3s occurred is beyond the economic resources of most ope~ating ma.'18.gements. The data in this paper giving the high lights of the water problem and indicating what appears to be a step in the right direction are based upon observations made during the past year that the industry desires and believes it is to the npublic interesttr to keep mine workings free of flood end surface waters.

May 1, 1941

By John Ward Smith

Variations in specific gravity of oil retorted from oil shales of the Eocene Green River Formation in northwestern Colorado were evaluated statistically, demonstrating that these variations are very strongly associated with stratigraphic position and less strongly but still significantly associated with geographic location. Specific gravity of oil retorted from these oil shales apparently varies with the carboxyl group content of the oil shale's organic matter. Higher temperatures accompanying increasing depth of burial probably progressively decarboxylated oil shale's organic matter producing the decrease of oil specific gravity associated with deeper stratigraphic position. The geographically associated oil-gravity variations were probably produced by regional variation in the original thickness of late Cenozoic extrusive rocks once overlying the Green River Formation.

Jan 1, 1966

By M. R. Geer

The Bureau of Mines examined the washability data for 25 Appalachian coals requiring low-density washing to reduce sulfur content to 1 percent, using the distribution-curve method. The purpose was to estimate how closely theoretical sulfur values could be approached, what yields of washed coal could be expected, and the recovery efficiencies that might be achieved. Assuming that the run-of-mine coal would be crushed to 3/8 inch and cleaned in dense-medium cyclones, the calculations indicate that theoretical sulfur contents could be approached closely when cleaning at a specific gravity of separation as low as 1.30. With coals that have favorable specific gravity compositions the recovery efficiency anticipated for cleaning at 1.30 specific gravity is surprisingly high. Similar calculations for cleaning with concentrating tables at intermediate specific gravities indicated that theoretical sulfur contents at 1.50 specific gravity could be approached closely with some coals but not with others. The calculations suggest that operating a table at a specific gravity of separation much lower than about 1.50 probably would be unsatisfactory with most coals.

Jan 1, 1968

By O. C. Blade

This report on the properties of aviation gasolines and aviation jet fuels produced in the United States during 1953 was made under a co-operative agreement between the American Petroleum Institute and the Bureau of Mines of the United States Department of the Interior. Analytical data are presented for 101 samples of aviation gasoline which include, for the second time in this series of reports, data on some samples of grade 108/135 aviation fuel. Data also are given for 32 samples of aviation jet fuel. The analyses were made on samples typical of the manufacturers' production in their laboratories and the results sub-mitted to the Bureau of Mines for compilation. The products of 19 manufacturers of aviation gasolines and of 19 producers of aviation jet fuels are represented.

Jan 1, 1954

By Seth C. Schaefer

The Bureau of mines investigated thermodynamic properties of MnSO4 and 2CdO CdSO4 to obtain basic thermodynamic data applicable to the treatment of mineral concentrates during roasting and sintering processes. Standard Gibbs energies of formation were determined with high-temperature galvanic cells using stabilized Zr02 as the electrolyte. Potential measurements were obtained from the cells?

Jan 1, 1983

By J. D. Davis

On May 15, 1936, Congress authorized the Bureau of Mines to conduct certain studies, experiments, and. investigations of subbituminous coal and lignite.4/ Appropriations were made in July 19 7, and since that date an active investigation has been underway to complete the provisions of the act. Part of the investigation has included a comprehensive survey of the known properties of the lower-rank non-coking coals, and provisions were made to obtain more data on certain varieties. In line with this plan, a typical subbituminous coal was selected for an extended series of tests in the standard. Bureau of Mines-American Gas Association unit,5/ at the Central Experiment Station. This particular noncoking coal was the first one of its rank that had been tested in the apparatus; for this reason the results are of particular interest because the testing apparatus was originally designed for use in studying the coke- and gas-making properties of coking coals. The test as described below has been developed by the Bureau of Mines since 1927 through a cooperative agreement with the American Gas Association.6/ Ninety to 180 pounds of coal is heated in a circular retort, 13 to 18 inches in diameter, at wall temperatures ranging from 500°C. to 1,110°C. in 100°C. steps. All products are collected and measured; their physical and chemical properties are then carefully determined to ascertain the gas- and coke-making properties of the coal. During the last 10 years approximately 50 representative American coals have been tested in the Bureau of Mines equipment. The results on the first 30 coals and a complete description of the test procedure are contained in a joint publication of the Bureau of Mines and the American Gas Association.7/ The remaining twenty coals have been reported in Bureau of Mines reports as Technical Papers and Bulletins.

Jan 1, 1939

By L. Kaufman

A range of processing conditions and compositions have been evaluated in order to optimize the properties of TiB2-(Ni,Cu) composites for application as a non-sparking tool material for use in coal mining operations. Fifty billets containing from 70 to 9S weight percent titanium diboride were hot pressed at 3000 psi between 2400°F and 2650°F. Samples which were cut from these billets were used to measure hardness, bend strength and impact strength so that composition/processing optimization could be effected. Eight compositions selected on this basis were evaluated by incendivity tests in order to choose the best composition. The best results were obtained for an 85 w/o TiB2-12 w/o Cu-3 w/o Ni composite hot pressed at 2650°F and 3000 psi. This material appears to be the best choice for fabrication of coal cutter bits to be evaluated in field tests.

Jan 1, 1973

By A. W. Fahrenwald

"About two years ago the Bureau of Mines, Department of the Interior, and the University of Idaho undertook an investigation of classification in its relation to table concentration of Idaho ores. The cooperation of the management of the Bunker Hill & Sullivan Co. in placing at our disposal their West Mill and facilities as desired, offered an unusual opportunity for studying the field of hindered classification in its practical and economic relation to table concentration.It has been shorn theoretically, and demonstrated experimentally, that ore products are more easily and economically concentrated on tables if the natural feed, consisting of various minerals and of all sizes of particles of each mineral, be classified or grouped into a series of products in which the mineral particles of greatest density are small in diameter relative to the diameter of the mineral particles of lesser density. Products in which the maximum difference in diameter of light and heavy minerals occurs are to be obtained only by true hindered settling classification. To our knowledge there has never been a really good hindered settling classifier used in practice and the present tendency seems to be to by-pass any attempt at such classification.After a careful study of the nature of hindered classification and of the requirements for hindered settling in practice, a classifier has been developed that takes fullest practical advantage of the widely known, but generally only meagerly understood, condition of hindered settling so well analyzed a number of years ago by Dr. Richards.The present paper presents briefly some of the more important practical results accruing through the investigation."

Jun 1, 1924

By Fred C. Turin, Lisa J. Steiner, Kim M. Cornelius

Like many experienced workers, remote control continuous miner operators perform their everyday jobs making choices and decisions that they may not consciously think about. While performing tasks, they are continuously processing feedback and cues which guide them for the next move. Initial training teaches the operators the tasks necessary to operate the equipment and perform the job. However, with experience they are better able to deal with hazardous conditions and non routine situations. To better understand what potential cues and feedback help to guide the operators, a questionnaire was developed to learn what factors affect decisions. Operator responses address issues related to specific tasks, equipment operation, visibility, lighting, and communication issues. The information collected is useful to understand what cues experienced operators use to make task performance decisions. Results will be used to develop interventions and training for safe and effective operator performance.

By David C. Oyler

The U.S. Bureau of Mines studied the interaction of longwall shield supports and adjacent strata at the Meigs No. 31 Mine in southeastern Ohio. Twenty-three legs of twenty shields at midface were instrumented with pressure transducers and monitored for 11 weeks. During the project, leg setting pressures were reduced twice to determine the effect of setting pressure on shield-strata interaction. No correlation was observed between setting pressure and leg loading rates. The shield loading profiles were consistent with a model in which the roof consists of two zones, a thin immediate roof loading the shields well below the typical setting force and a main roof zone essentially supported by the coal and gob and loading shields through its convergence. This model was used to develop an equation for estimating average loading rates at the site. The only variable of the equation is time, and the equation consists of an exponential term to account for the immediate roof loading and a linear term to account for main roof loading. The equation gave good correlation with average loading rates, but the variation in loading from cycle to cycle was too great for the equation to give good predictions of individual cycle loading rates.

Jan 1, 2010

By W. J. Kroll

The production of beryllium metal and its alloys is one of the most difficult tasks in metallurgy. In this report we shall examine the progress made in this work- in the last 15 years; taking into account the outstanding publications, including; those of the patent literature, and the information obtained during our 20 years? experience with this metal. The difficulties experienced' in producing elementary beryllium derive from the physical nature as well as from the chemical behavior of the metal and its compounds. Its oxygen affinity is about the same as that of calcium and a little higher than that of magnesium. Its chlorine affinity is much lower than that of magnesium, about equal that, of manganese, and little higher than that of aluminum. The sulfur and nitrogen affinity is probably almost the same as that of calcium for these elements, and beryllium carbide is probably more stable than aluminum carbide, A14C3. The intermetallic affinity of beryllium may be given in descending order, as follows: Nickel - copper - iron. It forms eutectics with -aluminum and silicon as well as with silver. It does not alloy with magnesium and only partly with calcium. Its oxide melts at 2,570° C., but CaO and BaO form readily fusible eutectics with BeO(65).3/ No igneous solvents are known for BeO, which behaves id this regard like Mgo. The beryllium silicate is a strong compound, the aluminete much less so; however, CaO easily displaces Be in the heated mixtures. The Anhydrous chloride hydrolyzes, and it cannot be made from aqueous liquors. It sublimes at 488° C, and melts at 405° C., The fluoride, which, is very Soluble in water, hydrolyzes also, but a kind of oxyfluoride of the approximate formula 2 BeO?5 BeF2 can be made from solutions by dessication. The fluoride melts at 800° C, and boils above 1,100° C. It forms very stable double fluorides with alkalifluorides, which have very low melting points and are fairly soluble in water. They are more stable than the analogous fluosilicates and the sodium fluoaluminate cryolite.

Jan 1, 1945

By Philip G. Freeman

The growth-promoting properties of coal-derived humus were tested by a variety of bioassay methods. Humate materials used included leonardite, a form of naturally oxidized lignite, and humic acids extracted from leonardite. It was found that the greatest effects were evident when water-soluble humic acid was applied to excised root tips. No significant short-term effect was noted when water-soluble humic acid was applied to stem or coleoptile sections. Root initiation was promoted in bean stems when high concentrations of coal-derived humate were applied. Gross weight of tomato plants was increased by up to 40 percent when coal-derived humates were added in concentrations of 101 to 104 ppm to the nutrient in a hydroponic growth test of 6 weeks' duration. It is concluded that coal-derived humate promotes the uptake of minerals, specifically iron, by serving as a metal chelate.

Jan 1, 1968

By H. -F. Krausse

Roof failures in underground coal mines are related to the lithology and geologic structure of the roof. There are two distinct suites of roof rock above the Herrin (No. 6) Coal in Illinois, and each has distinctive patterns of structure and roof failure. In black shale-limestone roof areas, roof instability is correlated with thinning of limestone beds and presence of faults and clay dikes. In gray shale roof regions, the prime roof hazards are posed by rolls, shear bodies, and presence of coal or carbonaceous partings in the roof. Most structural features examined are believed to have formed during early stages of sediment diagenesis and compaction. Structural trends and lithologic patterns are strongly interdependent for this reason. In many cases geologic patterns are so complex and locally variable that prediction of roof stability far in advance of mining is difficult. The need for greater flexibility in roof control planning is apparent.

Jan 1, 1979

By Jr. Reistle

The tests reported in this paper were made in the East Texas field in the summer and fall of 1932 as a part of the Bureau of Mines study of the operation of flowing wells and reservoir performance; and to determine, if possible, the minimum reservoir pressure necessary to produce the wells in this field by natural flow through different sizes of flow strings. The minimum reservoir pressure that would be required to Maintain natural flow through 2 1/2-inch tubing was determined experimentally for the existing energy conditions in the East Texas field. With the present available data, however, it is impossible to predict accurately or to determine by calculation the necessary energy requirements for maintaining the vertical flow of oil and gas mixtures under all conditions. Although some valuable data were obtained which seem to have application to the solution of problems involving vertical flow, this important research of the petroleum industry is so involved that more study of the complicating factors influencing the flow of oil-gas mixtures through vertical pipes is required.

Jan 1, 1933

By Laurance L. Oden

Titanium-enriched smelter slag produced commercially by Quebec Iron and Titanium Corp., Sorel, Quebec, was evaluated as feed material for a process developed by the Bureau of Mines to prepare rutile. Glass-forming agents including P205, B203, and two binary mixtures were added individually to the as-received and preoxidized smelter slag, and the nonferrous tramp oxides were effectively partitioned into the resulting noncrystalline phase. Iron in the ferrous oxidation state was moderately soluble in the glass of reduced specimens but less soluble under oxidizing conditions. The solubility of iron oxide in phosphate glass exceeded the solubility of iron oxide in borate glass. Effective conversion of titanium oxide to rutile was not achieved in the high-iron commercial smelter slag, and 20 to 30 pct of the titanium remained as pseudobrookite, a mixed iron-titanium oxide.

Jan 1, 1973

By J. A. Woolf, E. S. Leaver, N. K. Karchmer

"In the cyanidation of silver ore, the need of oxygen is well recognized. Various methods have been introduced for supplying the oxygen. In usual practice, air is the source of oxygen and the methods of application are mechanical.This article gives the results of touts made to show the rate of dissolution of silver from each of the common silver minerals in cyanide solution, under conditions similar to those used in the practical recovery of silver from its ores. The effect of oxygen in aiding the dissolution of the silver from each mineral is also shown by a comparison of the methods of supplying the oxygen. Oxidation by preliminary roasting (500°C.) of each mineral sample gives the maximum extraction of the silver by treatment with cyanide.Each silver mineral5 used in these experiments was as pure as could be obtained from the mineral dealer. In their natural occurrence, silver minerals are not usually free from mineral impurities. They are usually closely associated with other minerals often forming, a complex mixture. The form of crystallization, the proportions, and properties of the diluent that incases or has been dispersed with the silver mineral may decidedly affect the dissolution rate of the silver from each mineral. While the following results should aid in the cyanidation of silver ores, each ore should be studied from the basis of the form and condition of the silver that is to be recovered.All the tests reported in this article were made on synthetic samples, prepared by mixing the particular silver mineral with clean sea sand. Each mineral was ground in an agate mortar to pass 100-mesh before mixing with the sand which had previously been ground in a porcelain pebble mill to 100-mesh. Such proportions of each mineral and the sand were used as to give a head assay of approximately 20 ounces of silver per ton to the synthetic sample.Agitation was carried on in stoppered bottles approximately one-third full of pulp, method apparently supplied all the atmospheric oxygen that would be taken up by the solution under usual conditions, because tests conducted in open bottles did not show increased recovery,"

Jan 1, 1931

By John Neil, John Bli ard

Coke breeze consists of the smaller particles of coke formed by handling coke on and after removal from the ovens. Its value as F, fuel is less than that of the larger pieces, both because the smaller pieces contain more ash and therefore have a lower calorific value, and because a greater draft is required to burn it.The tests described below show its value as a fuel when mixed with bituminous coal and burned in a hand fired boiler of a size considerably greater than that used in an ordinary house. The results of these tests, however, can be used to give a fairly good indication of the value of coke breeze when burned with bituminous coal in a domestic furnace.All who fire a domestic furnace know that for only a comparatively short part of the day, and then only on a few days, is it necessary to open fully the ash, pit door and stack damper to get the required rate of combustion in the average furnace in the average house. It will be practical, therefore, during the greater part of the heating season, to fire coke breeze with the coal and use more of the available draftsFor domestic heating the coke breeze should be stored separately, and used when the draft is sufficient to burn it in mixture with bituminous coal, at the rate required to warm the house.Purpose of tests: The tests were carried out at the request of the Chamber of Commerce of Pittsburgh, Pa., in order to determine the steaming value of coke breeze as a fuel when mired with Pittsburgh coal and fired by hand, and to see whether the mixture when burnt would give off an objectionable quantity of make.

May 1, 1921

By Jeffrey H. Welsh

The Bureau of Mines studied the use of computerized, continuous, remote monitoring systems for safety from power system faults in underground coal mines. In this report the need to improve protection against power system faults is documented, and types of faults are identified. The relationship between mine safety regulations and computerized, continuous, remote monitoring is analyzed.

Jan 1, 1983