Search Documents

By W. R. Huff

This report describes the development and operation by the Bureau of Mines of a pilot plant designed for using high-volatile A bituminous coal-in-water suspensions as a source of preheated coal and superheated steam in the pressure gasification of coal with oxygen. Figure 1 on page 2 is a block diagram of the integrated gasification process, in which a total of 70 tons of coal was fed from slurry and gasified. The present work included (1) development of equipment and methods both for mixing pulverized coal and water to produce slurry and for pumping and metering the slurry at gasification pressure; (2) development of equipment for heating the flowing slurry and, because slurry that can be pumped produces more steam than is necessary as a gasification reactant, developing equipment for removing and metering the excess steam; and (3) demonstration of the process under actual gasifier operating conditions, at a coal rate of about 800 pounds per hour and gasification pressures in the range 100 to 300 pounds per square inch gage. By using the forced-convection principle, a flow of slurry made from a caking, high-volatile A bituminous coal can be continuously heated to 600° F. in a coil-type heater. The flow rate and concentration of the slurry and the temperature gradient along the length of the heating coil must be closely controlled. In a radiant-type heater, involuntary reductions in flow rate, even momentary, can lead to coking and plugging of the heater coil.

Jan 1, 1961

By K. K. Kershner

To meet an increasing demand for high-purity cobalt, the Bureau of Mines has conducted investigations for producing this metal. Cobalt having a purity of 99.95 percent or higher is needed to determine heats of formation, corrosion resistances, phase diagrams, and other basic properties of the element and its compounds. This grade of cobalt may be used for preparing radioactive metal. As a result of its investigations a detailed procedure, which is of practical significance to the production of high-purity cobalt, has been developed by the Bureau for purifying cobalt solutions and for electrolytic deposition of the metal. Cobalt metal, which had a purity of 99.99 percent with reference to metallic contaminations, was deposited electrolytically. Qualitative spectrographic analysis showed only traces of calcium, copper, iron, magnesium, nickel, and zinc.

Jan 1, 1956

By Ralph H. Espach

In the spring of 1943, when it was evident that the Tensleep sandstone in the Elk Basin field, Wyoming and Montana, held a large reserve of petroleum, Bureau of Mines engineers obtained samples of oil from the bottom of nine wells and analyzed them for such physical characteristics as the volumes of gas in solution, saturation pressures or bubble points, shrinkage in volume caused by the release of gas from solution, expansion of the oil with decrease in pressure, and other related properties. The composition of the gas in solution in the oil was studied. The pressures and temperatures existing in the reservoir and the productivity characteristics of the oil wells were determined. The data obtained indicate that the oil in the Tensleep reservoir of the Elk Basin field has unusually varying physical characteristics, such as a saturation pressure of 1,250 pounds per square inch absolute and 490 cubic feet of gas in solution in a barrel of oil at the crest of the structure, and a saturation pressure of 530 pounds per square inch absolute and 134 cubic feet of gas in solution in a barrel of oil low on the flanks. The hydrogen sulfide content of the 6a r; in solution in the oil varies from 18 percent for oil on the crest to 5 percent for oil low on the flanks of the structure. Of even greater significance is the fact that these and other variable characteristics of the reservoir oil are related to the position of oil in the structure. Many geologists and petroleum engineers have considered all the oil in a petroleum reservoir to have uniform physical characteristics and that equilibrium conditions prevailed in all underground accumulations of oil and gas. That such is not always so is borne out by the results of the study made by the writers.

Jan 1, 1951

By H. D. Jacobs

The Bureau of Mines undertook a research program to insure an adequate supply of iron raw materials for future iron and steel making needs. A sample was obtained of oxidized taconite from the western Mesabi Range in Minnesota, and the metallurgical response of the taconite to beneficiation by a process that included selective flocculation-desliming-cationic flotation was evaluated. The sample contained 35.3 pct iron and represented approximately 2 billion tons of crude material. Selective flocculation and flotation were evaluated in a pilot plant with a feed rate of 900 Ib/hr. Concentrates averaging 61.7 pet iron and 5.1 pet silica were obtained, with an accompanying iron recovery of 67.2 pet. About 83 pct of the process water requirements were reclaimed from the slime and froth tailing and then recycled.

Jan 1, 1980

By Danny Hagood

The drilling of horizontal boreholes as a means of degasification in advance of mining has been tried at Jim Walter Resources, Inc., No. 4 Mine. In a joint venture with the U.S. Bureau of Mines, a series of horizontal drainage boreholes have been drilled in the panels of an advancing continuous miner section with impressive results. The combined methane gas production rate has ranged from 205,000 to 680,000 cfd (cubic feet per day} with individual "in-seam" horizontal holes producing up to 332,000 cfd. The methane liberation from the ribs for the entire panel length has decreased from an average of 8.75 cfm (cubic feet per minute) per 100 feet of entry to 4.05 cfm per 100 feet, a 54 per cent reduction. The actual gas concentration as measure at the surface discharge point normally ranges from 85 per cent to 95 per cent methane. As a consequence of the significant reduction in methane liberation rates from the panels of the section, a 50 per cent increase in productivity from the section has been realized.

Jan 1, 1983

By W. O. Vanderburg

The leasing or tribute system has been an important factor in the development of our metal-mining industry, particularly in the gold and silver mines of the Western States. It has received its widest application in. the early history of many camps and in the last stages of many mines. The system is especially adapted to mining where the ore's occur in narrow veins or are erratically distributed in small bunches or pockets so that selective mining, hand sorting, screening, or hand cobbing is required to produce shipping or milling-grade ore. The leasing system is also applicable to the development of prospects where the owners are unable or unwilling to assume the risks of searching for ore. The virtue of the system lies in the opportunity it affords miners with little capital to get started; at the same time, it rives owners an opportunity to have their property developed at small cost.

Jan 1, 1934

By J. W. Jensen

Alloys of manganese and copper containing from 65 to 80 percent manganese possess mechanical strength and vibration-damping capacity in an unusually high degree. The success of their use in reducing vibration in structures depends, to some extent, on their fatigue properties. This report describes the results of fatigue tests on alloys of four compositions. Three metallurgical conditions were investigated for each alloy. Or the basis of the data in this report, the general rule that vibration-damping manganese-copper alloys are comparable to mild steel in hardness and strength may be extended to include fatigue strength. Methods for casting and fabricating these alloys were described in a previous report,4 which contained data on the mechanical and damping properties of the solid-solution alloys, and on alloys aged for 2 hours at 450° C. The aging heat treatment of solution-treated alloys results in optimum mechanical and damping properties throughout the range of specified composition. However, in the present work, measurements also were made on alloys aged for 2 hours at 500° C., because it was theorized that the additional precipitation of a-manganese under these conditions might have a pronounced effect on the fatigue strength of the alloy.

Jan 1, 1961

By H. G. Iverson

As a part of the program of investigation of domestic sources of manganese ore, mining engineers of the Bureau of Mines examined and sampled three properties in the vicinity of Winnemucca, Nev. As the ores were too low grade for direct production of ferromanganese, they were tested for their amenability to concentration by ore-dressing methods. Two samples of ore were procured by examining engineers of the Bureau of Mines from several outcrops in the Pollard Canyon area, Pershing County, about 30 miles southeast of Winnemucca. The manganese occurs in relatively small lenticular bodies as secondary replacement deposits in chert and quartzite. The first sample represented average run -of -mine ore as exposed in the Pollard Canyon deposits. Sample 2 was composed of hand-sorted, high-grade ore.

Jan 1, 1954

By R. L. Grayson, S. S. Peng

"Abstract. Sampling of respirable dust and analyses of samples have been partially completed for a longwall panel. Physical and compositional properties which have been characterized include:l. Respirable mass concentration, 2. Mineral composition,3. Particle size distribution by mineral,4. Particle shape distribution by mineral,5. Particle angularity distribution by mineral, and6. Respirable size distribution.Analytical techniques used in the characterization of samples are described, and results are reported with emphasis placed on relationships between the various characteristics and worker locations. Details of existing mining conditions, equipment arrangements, dust control methods and operating system parameters are presented.INTRODUCTIONThrough the work of many researchers worldwide, the health of coal miners in modern societies is now protected from dangerous exposure to respirable coal mine dust. A vast amount of research culminated in the exposure-response model of Jacobsen, et al. (1971) whi3h has been used to establish the 2mg/m exposure limit in the United States. According to the model, exposure to respirable dust for 35 years at this level or less would prevent the occurrence of a clinically significant case of coal workers' pneumoconiosis (CWP). The exposure limit, of course, must be adjusted whenever greater than five percent free silica exists in the respirable dust.The Jacobsen model was built around a mass concentration exposure, which showed the highest correlation with incidence and progression of CWP. As Morgan; et al. (1973) noted, howev.er, the quantity of respirable dust inhaled is not the only significant factor. It is noted that although mass of respirable dust correlates highest with the incidence of CWP, it is not a causal factor. Indeed, the insidious processes causing the disease occur on the cell-particle scale, requiring microscopic investigation."

Mar 1, 1989

By Ronald A. Munson

Samples of the naturally occurring zeolites phillipsite, clinoptilolite, erionite, and chabazite have been surveyed for their gas adsorption, ion exchange, and other characteristics. Chabazite and erionite, which are generally more stable, also have higher methane adsorption capacities than do the other natural zeolites. Both natural erionite and natural chabazite are classified as small-port zeolites on the basis of their inability to adsorb chlorotrifluoromethane. In the range of 8 to 100 mesh, the adsorptive capac-ity of natural zeolites is improved only slightly by a decrease in particle size. The capacity of natural clinoptilolite to adsorb methane is increased by cation replacement by the hydrogen ion and decreased by exchange with calcium ion. Natural phillipsite, which is easily decomposed by heat, adsorbed methane to a limited extent.

Jan 1, 1973

By T. R. Rehak

Blasting operations are an essential element in the recovery of our Nation?s mineral resources. The mining industry uses billions of pounds of explosives annually. The majority of blasting occurs in surface mining operations. Blasting results in the fragmentation and often the projection of rocks. Frequently, the rocks are thrown beyond the expected limits. Flyrock and failure to secure the blasting area dominate blasting-related accidents in mining, especially in surface mining. Blasting accidents in the mining industry tend to result in critical injuries or fatalities. Accident reports and information collected from the Mine Safety and Health Administration (MSHA) and other government agencies provide supporting evidence. According to the data collected, blasting-related accidents (in mining) were 11 times more severe than all other types of mining accidents. Blasting accidents are not unique to mining operations - the same situation exists in the construction field. In this paper the authors have compiled a list of the primary causes of flyrock and the failure to secure the blast area. In the next phase of this project, typical blasting scenarios will be reviewed which will highlight the main reasons flyrock and/or lack of blast area security occur. This will alert miners and construction workers to the current problems/hazards associated with blasting and to identify other safety measures to protect personnel.

Jan 1, 2000

By H. D. Baylor

This is the first of a series of papers describing mining methods and costs at cement plant quarries throughout the United States and deals directly with those methods employed and costs obtained at the quarry of the Louisville Cement Co. located at Speed, Ind. ACKNOWLEDGMENTS The author wishes to acknowledge the assistance of Mr. J. M. Buohheit, superintendent of quarries, and Mr. H. E. Schoonover, quarry engineer, in furnishing data and in compiling this report.

Jan 1, 1930

By E. C. Perkins

Preliminary experiments are reported utilizing bacteria to leach manganese from a variety of domestic low grade manganiferous materials. In two large leaches manganese extraction ranged from 71.7 to 92.5 percent, and the products analyzed over 48 percent manganese. Nutrient requirements and leaching time experiments were made. The mechanism of leaching is not understood, but is different than the mechanism encountered in the microorganism accelerated leaching of copper in the presence of sulfide minerals.

Jan 1, 1962

By W. W. Adams, T. D. Lawrence, D. R. White

"This paper presents the results of the eleventh yearly accident-prevention contest, the National Safety Competition of 1935, conducted by the United States Bureau of Mines. Participating in the competition were 336 mines and Quarries in 37 States. Five mining or quarrying companies, each the leader in its group for having established the best safety record during the year, were awarded the national safety trophies 'Sentinels of Safety.Since these annual contests were begun 11 years ago the scope of the competition has been broadened materially, both as to the number of plants participating and as to the number of man-hours of exposure to accident hazards. Moreover, marked progress in the pre¬vention of accidents has been achieved, as is indicated by an almost constant downward course in the accident-frequency rates for the contest group as a whole during the past 11 years. On the other hand, the accident-severity rates for the group showed an upward trend during the first part of the period and a downward trend during the latter part, except in 1930 and 1934, when two disastrous explosions occurred with heavy loss of life, and in 1935, when there was an increase in the number of fatalities although no major disasters occurred. The accident rate for 1935, both as to frequency and severity, was higher than for 1934.The National Safety Competition is conducted by the Bureau of Mines in the interest of safety in the mining and quarrying industries. This object is accomplished directly through the efforts of the competing companies and their employees to win first place in the competition and thereupon receive well-merited and national recognition for their achievement. Indirectly the purpose of the contest is accomplished through studies by the Bureau of Mines of the fasts contained in the accident reports which the competing companies furnish to enable the Bureau to compute the accident rates that are the basis for determining the winners of the contest.The statistics that constitute the basis for determining the winning companies and the relative standing of all companies are prepared uniformly without regard to the States in which the companies operate, or to differences in classes of accidents covered by State laws relating to compensation for injuries resulting from industrial accidents."

Jul 1, 1936

By A. F. Colombo, D. W. Frommer

Bench- scale tests were made to determine the applicability of flotation as a means of upgrading finished and semifinished magnetic concentrates prepared from reductively roasted iron ores . Both anionic and cationic flotation methods were used to remove siliceous gangue from the magnetic concentrates and produce upgraded products . Seven magnetic concentrates , containing from 6.7 to 13.7 percent SiO2 , were improved by the flotation treatment , yielding final concentrates containing less than 6.0 percent Si02 . Cationic flotation methods were studied on four of the seven samples ; of this group only one sample yielded better results by cationic flotation than by the anionic method .

Jan 1, 1964

By D. Harrington, R. R. Sayers

For several years the writers have been studying various phases of the effect of air conditions in metal mines upon underground workers ; in 1918 a short study was made in certain hot and deep mines and brief reports were issued in the Engineering and Mining Journal ( August , 1920) and in the U. S. Public Health Reports (Vol . 36 , No. 4 , January 28 , 1921 ) . In 1921 a more extended study was made (also in hot and deep metel mines ) with intent to determine the limiting conditions imposed upon underground workers by the physiological effect of various air movements , temperatures , and humidities , with and without work . It is the purpose to publish a series of short papers on this later investigation , each paper to consider one particular phase of the work . The present paper deals with the effect on body temperature and pulse rate in still air as compared with moving air of temperatures from 90 to 100° F . and 100 per cent relative humidity, the subjects at rest .

Apr 1, 1923

By James A. Whelan

The Bureau of Mines sponsored research studies of variables in rotary drilling, done in the Department of Mineral Engineering, University of Minnesota. By studying carefully controlled drilling with good instrumentation, it was hoped to obtain a better understanding of rock failure during drilling and of the stresses in drill bits during drilling. Experimental procedures and equipment are described. From these studies it was concluded that 1. Thrust requirements, other things being equal, are proportional to the total length of cutting edge in the bit. 2. Data from penetrating a wedge into rock under thrust only are not directly applicable to rotary drilling. 3, In rotary drilling the initial wear on a bit greatly decreases penetration rate under any given set of conditions; however, after initial wear the effect of wear on penetration rate is reduced. 4. An increase in rotary speed increases the overall penetration rate but decreases the penetration per revolution. 5. An increase in thrust increases the overall penetration rate and the penetration per revolution. 6, Torque on a drill bit is proportional to both penetration rate and bit diameter. 7. For small-diameter holes full-hole drilling will save both drilling time and energy compared with pilot drilling followed by reaming; for large-diameter holes pilot drilling-reaming is advantageous in both respects,

Jan 1, 1962

By R. T. Johansen

The adverse effects on waterflooding and well-completion methods of clay minerals indigenous to petroleum-production formations recently have received considerable attention. Knowledge of the types and amounts of clay minerals present would allow estimates of the response of such formations to injected or infiltrated water; however, the random distribution of clays in sedimentary formations makes direct evaluation of ?water sensitivity? desirable. A method for the direct evaluation of water sensitivity has been developed, based on measurement of water-vapor adsorption. Correlation of such data with the results of nitrogen-adsorption measurements provides valuable information on the content and properties of clay minerals in sedimentary rocks. The method is relatively simple and has the advantage that it may be used with small, irregularly shaped chips or shale-streaked samples, as well as with typical core samples. Methods previously employed required separating the clay from the rest of the reservoir-sample material and then performing a clay analysis either by X-ray diffraction, differential thermal analysis, liquid permeability, or a combination of these methods (2,3) .3/ This water-vapor-adsorption method requires measuring only a few points on the isotherm to tell whether or not the sample is water sensitive. The goal of these measurements is not to determine the type or amount of clay present, but what will be its sensitivity to flood water. This method gives a direct means of solving this problem.

Jan 1, 1958

By Kenneth M. Earl

In its investigation of deposits of strategic minerals, the Bureau of Mines did some development drilling at the New Galena Deposit in an endeavor to find an additional source of supply of lead. In Bucks County, lead and zinc minerals have been found in shales over a largo area west and northwest of Doylestown. Considerable mining has been done in the vicinity of New Galena on the North Branch of Noshaminy Creek, 3 miles northwest of Doylestown. It has not been possible to obtain a satisfactory history of the New Galena mine, as there is much disagreement in statements. Most of the mining was done in open pits. Two shafts were sunk to shallow depth; one of these became part of the main pit' which is 256 foot long, 50 to 75 feet wide, and 20 to 44 feet deep. Small pits 8 to 10 foot square wore sunk on the ore zone, which extends some 1450 feet to the southwest. The rock containing the minerals is either black or gray shale. The gray material closely resembles limestone. The following minerals have been reported from the mine: quartz, ankerite, calcite, galena, sphalerite, pyrite, chalcopyrite, and bornite. Some of the galena has yielded 10 to 15 ounces of silver and 10 cents in gold per ton. The average grade of the ore as mined is not known. To investigate the downward extension of the ore shoot, the Bureau drilled two holes aggregating 373.9 feet, No additional ore was developed by this work.

Jan 1, 1950

By Raymond B. Lucas

"Distinction between Tripoli and Diatomaceous EarthMuch confusion exists both in the literature and in the trade as to the proper use of the terms tripoli, tripolite diatomeceons or infusoriai earth, and kieseigunr. All of these terms are often used synonymously by the trade and even in mineralogists and other reference books. Actually, tripoli is a ma- is a material of definite and distinct physical and chemical properties and all of the other terms belong to a different material with just as definite and distinct properties.Originally the term tripolite (loosely called tripole) was given to a diatomaceous cart from Tripoli in Northern Africa. Dena (J.D. Dana, A System of Mineralogy 6th Ed.) calls this material tripolite and gives no authority for the use of the terms tripoli. Between 1880 and 1890 the deposits near Missouri, were opened and the material placed on the market as ""Tripoli"" no doubt due to its resemblance in some respect to the original tripolite or diatomaceous worth from Tripoli. Since that time the term tripoli has with increasing definitenesss been reserved for the Seneca material and other siliceous of similar origin and physical properties, while all siliceous material of organic origin, containing dilators, has been called diatomaceous earth (or its synonyms infusorial earth, kiselguhr, etc.). Rottenstone is sometimes classed with tripoli."

Nov 1, 1920