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By Doyle A. Ellerbruch

An FM-CW microwave system was investigated for measuring coal layer thickness. Measurements were made in three different mines near Pittsburgh, Pennsylvania, near Fairview, West Virginia, and near Coffeen, Illinois. Microwave frequencies in the range 1-2 GHz were used to measure samples up to 55 cm thick. All samples were backed with a naturally occurring shale. Measurements were also made on coal and shale samples compounded in the laboratory at the Bureau of Mines Pittsburgh Mining and Safety Research Center near Bruceton, Pennsylvania. The results indicate that layer thickness can be determined in most cases, although large anomalies may, in some cases, produce misleading results. Many anomalies that were detected with the FM-CW system were verified visually by drilling into the coal layer. The dielectric constant of coal apparently varies significantly within a coal seam. The form of the output signals from the FM-CW system seem to simplify the data interpretation and analysis process as compared to the manually swept microwave system used previously. It appears that this technique has the potential of measuring changes in the dielectric constant of a coal seam and providing an output that can be used for real-time corrections in layer thickness; measurement.

Jan 1, 1976

By Edward L. Burwell

The Bureau of Mines conducted laboratory experiments to determine the change during retorting in the apparent permeability and the degree of compaction of beds of broken oil shale. Grades of oil shale studied ranged from 20.6 to 46.7 gallons of oil per ton (gpt), and the simulated overburden pressures applied to the shale were from 300 to 900 psi. Linear regression analysis of the data produced equations describing the response of the oil shale. Oil shales of approximately 20 gpt experience only minor apparent permeability reductions under test conditions, but richer shales (30 to 50 gpt) lose essentially all permeability. The permeability reductions were accompanied by corresponding decreases in bed height that ranged up to 37 percent of the original bed height.

Jan 1, 1974

By J. E. Dooley

Reference mass spectra and analytical correlations for 20 alkylcycloalkyl sulfides and two dicycloalkyl sulfides are presented 'to provide information that will facilitate the identification of sulfur compounds occurring in natural or synthetic mixtures. Reference spectra indicate relative intensities in addition to parent and base peak sensitivities. Analytical correlations establish the ionic species that reflect major fragmentation paths for the com-pounds studied. Specifically, the correlations show that base peaks are formed by several different processes: (1) Cleavage of the bond a to the ring, (2) fragmentation of the alkyl chain, and (3) fragmentation of the ring plus fragment contribution from the alkyl chain. Useful correlations for deter-mining alkyl chain length involve the CnH2+3S+ and CnH2n+1 + ions. CnH2n-2+ and CnH2n-1 S+ ions reveal the number of carbon atoms in the cyclic ring. Other important ionic species are also discussed.

Jan 1, 1970

By A. D. Garman

This paper presents one of a series of digests of foreign mining legisla- tion and court, decisions which is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate mines in various foreign countries. This interpretation of the laws of Latin America has been prepared from the best available information in Washington, but is released subject to correction and amplification, if necessary, by the proper American diplomatic and consular officers, to whom it is being referred through the courtesy of the Department of State. Individual abstracts of the laws of each of the countries herein discussed have been prepared and published separately. This general summary is presented for the use of mining engineers and investors whose interests extend over the borders of a single country. It is also designed to bring out certain general principles of mining law and, so far as feasible, to indicate the trend of mining legislation in South and Central America. In order to gain perspective, the details of legislation are not com- pletely covered in this paper, but an effort has been made to bring out essential differences as well as points of similarity in the laws of the various countries. The course of legislation is first traced chronologically and the points discussed are then arranged in tables in somerhat greater detail. .Si. With a very few exceptions the existing mining legislation of Spanish America is a development, of the Spanish "Law Decree of Bases" (more briefly referr- ed to as the "Decree-Bases") of 1868. This in turn was influenced, particularly in its classification of minerals, by the French law of April 21, 1810.

Jul 1, 1930

By E. J. Lintner

This paper is one of a series being prepared by the United States Bureau of Mines describing clay mining and crushing methods and costs at various operations throughout the United States. These papers are designed to disseminate technical information regarding methods used. The cost tabulations represent local operating expenditures only and not total production costs. It is recognized that publication of total production costs might perhaps, in many instances, cause embarrassment to the individual operator as well as to the industry as a whole. On the other hand, operating costs are essential to the technical discussion and study of the methods employed. The attention of the reader is specifically called to this distinction in order that no misunderstanding of the scope of the cost tabulation shall ensue. The following report deals specifically with the methods employed by the Camp Brothers Company, Mogadore, Summit County, Ohio.

Jan 1, 1936

By A. W. BELDEN

Among the investigations that the Bureau of Mines is conducting witha view to increasing efficiency in the utilization of fuels belonging to or for the use of the Government is an investigation of the processesthat take place in a foundry cupola during a melt. Some observations on the results of cupola tests of cokes at the Government fuel-testing plant in St. Louis, Mo., the coke being fromcoal from many coal fields of the United States, have been stated in a previous bulletin.s Especial attention was given to the meltinglosses that resulted from the use of different grades of coke, light and porous or heavy and dense. These losses amounted in one instance to 52.5 per cent of the iron charged and showed, in convincing manner, the need of exact information in regard to conditions in the fuelbed of the cupola.b Melting losses of iron have been fully appreciated but little under-- stood. The fact that these losses were possible with either light or heavy coke led to the belief that by using small charges 80 placed that. melting would take place in that zone of the cupola where the highest heat and the smallest percentage of oxygen prevailed and by confiningall melting to this zone these losses would be eliminated and the economical use of practically any coke produced for metallurgical purposes would become possible. This widening of the field from whichcoke might be drawn for foundry purposes would serve to place the foundryman in an independent position as regards his source of supply, and would tend to conserve the better grades of coking coals, which are being rapidly exhausted, by making the poorer grades available for mixing with them. In order to investigate conditions within a cupola, the Bureau of Mines as a first step decided to install a commercial cupola, to sample the gases during their travel from the tuy~res upward, and to determine the temperature of the fuel bed.

Jan 1, 1913

By Worthen Bradley

This paper describing the metallurgical practice and costs at the reduction plant of the. Sulphur Bank Syndicate, Clearlake, Calif., is one of a series of papers on the treatment of ores being prepared by the Bureau f Mines. The reduction plant and mine of the Sulphur Bank Syndicate are on the eastern shore of Clear Lake, in Lake County, Calif., 4 miles from the town of Clearlake and 125 miles north of San Francisco.

Jan 1, 1931

By Martin H. Stanczyk

The direct dissolution of a typical zinc sulfide flotation concentrate by elevated temperature and pressure leaching was investigated. The concentrate assayed about 55 percent Zn, 32 percent S, 6 percent Fe, and 1 percent Pb and contained minor quantities of copper and precious metals. The influence of various factors on the dissolution of the zinc in acidic and ammoniacal pulps when using oxygen as the oxidant was determined. The tests revealed that the sphalerite was difficult to oxidize. Complete dissolution of the mineral required vigorous and intimate nixing of the gaseous, liquid, and sold phases. The addition of pyrite or sulfuric acid to water slurries of the concentrate was required to obtain a high zinc extraction when leaching under acidic conditions. The quantity of pyrite and acid used was about 0.125 and 0.25 pound, respectively, per pound of zinc sulfide contained in the leach charge. In tests with acid, about 96 percent of the zinc was extracted from the concentrate in 1 hour at 200° C. when the oxygen partial pressure was 75 pounds per square inch gage or higher. Leaching with a continuous flow of air as the oxidant gave results that were almost as good as those obtained when oxygen was used, In tests with air fed through the autoclave at 320 liters per hour, 95 percent of the zinc was dissolved in 1 hour, Acid leach solutions assaying approximately 58 grams Zn per liter and containing Fe, Ni, Cr, and Cu impurities were produced in the better tests. The leached residue consisted essentially of red iron oxide together with substantially all of the lead and precious metals.

Jan 1, 1961

By W. L. Dare

This information circular is one of a series, published by the Federal Bureau of Mines, on methods and costs of mining uranium ore on the Colorado Plateau. This report describes the relatively small-scale operations of the Salt Wash miner: The mining method followed, the equipment used, and the production costs. It describes 10 lease-operated mines of Union Carbide: Nuclear Co. that are typical of Salt Wash operations on the plateau. These mines lie within the Uravan mineral belt3/ and arc in the Gateway, Bull Canyon, and Uravan mining districts. (See fig. 1.) Generally the ore bodies occur as irregular, discontinuous layers of ore minerals within sandstone beds in the Salt Wash member of the Jurassic Morrison formation. The ore bodies sometimes occur as rolls, pod associat with carbonaceous trash, or tabular masses. Their size and erratic distribution preclude the use of a prearranged and uniform stoping system. The mining method is simply to follow the ore and leave open scopes behind.

Jan 1, 1959

By W. J. McKenna

This paper, describing the milling practice at tine lead-zinc concentrator of the International Smelting Co., is one of a series of papers on milling methods being prepared by the United States Bureau of nines. The concentrator is operated as a unit of the International Smelting Co. and is located about 40 miles southwest of Salt Lake City, at Tooele, Utah. The Tooele Valley Railroad, operating between the plant and Warner, Utah, a distance of 6.5 miles, makes connection with both the Union Pacific and Denver & Rio Grande Railroads.

Jan 1, 1933

By Cheryl Hill, Michael Keane, Pamela Mike, Raghoottma Pandurangi, William Wallace, Mohindar Seebra, Val Vallyathan

"Dipalmitoyl glycerophosphorylcholine (lecithin) dispersed in physiologic saline, a model of the primary component of pulmonary surfactant, is adsorbed by respirable quartz and aluminosilicate dusts. Dust cytotoxicity as measured by erythrocyte bemolysis and pulmonary macrophage enzyme release is suppressed by this adsorption. The degree of suppression of hemolytic potential versus specific adsorption of lecithin from dispersion in saline by respirable quartz and kaolin dusts are compared with dusts' BET specific surface areas to interpret the prophylactic effect of lecithin adsorption. Dust hemolytic potential versus medium pH is presented. Fourier transform infrared spectroscopy and photo-acoustic spectroscopy of lecithin on quartz and of lecithin on kaolin are presented and reviewed with results of studies of the time course of removal of lecithin adsorbed on mineral surfaces by digestion by phospholipase enzyme. Results are discussed in terms of a model of prompt neutralization of respired mineral dusts by pulmonary surfactant, and a gradual re-toxification by digestive processes acting on the adsorbed prophylactic surfactant coating following phagocytosis. INTRODUCTIONQuartz dust of respirable size is well known to cause fibrotic lung disease, but numerous questions persist in the understanding of the initiation and progression of this disease. Our approach concentrates on physical and chemical aspects of mineral dusts early-on in their interactions with living organisms, and we have chosen simplified models to investigate that interaction.In the alveolar ·spaces of the lung, tissue is coated with a surface-active material (pulmonary surfactant), which, among other functions, mechanically stabilizes the lung from collapse by reducing the surface tension of water in the alveolar sacs.1 This surfactant is also the material that is first contacted by a mineral particle that is transported to an alveolus and is impacted there. This surfactant material has been studied extensively. The primary components are known to be proteins (about 11 % in dog lavage fluid), and phospholipids (about 88%).2 Pbosphatidyl cholines constitute roughly 80% of the phospholipid fraction; about 70% of the phosphatidyl choline fraction is dipalmitoyl lecithin (DPL).2 Respirable aluminosilicate particles are capable of adsorbing dipalmitoyl lecithin from dispersion in physiologic saline, a model for a possible initial event occurring upon deposition of a particle in a pulmonary alveolus. As may be seen from Figure 1, the DPL molecule has several fixed charges at neutral pH; a positive charge on the trimethylamine (choline) moiety, and a negative charge on the phosphate group. Also evident are the two fatty acid residues of palmitic acid, which are bonded through ester likages to the glycerol segment of the molecule. The fatty acid moieties of phosphatidyl choline make the molecule inso1uble in aqueous solutions under normal conditions, but a colloidal unit of aggregated molecules called a micelle is usually formed spontaneously above a certain minimum concentration. Small micellar vesicles are generally formed in the laboratory by using ultrasonic agitation or by solvent evaporation methods."

Jan 1, 1990

By D. Harrington

Fire is always a serious-menace, whether in a residential or in an industrial region; in wartime it is particularly damaging in an industrial plant. The mining industry is especially vulnerable, as its plants are generally more or less isolated front centers of population and do not have access to modern fire-fighting equipment; moreover, owing to the transitory rapture of most mines, their surface structures; are often relatively flimsy and flammable.. Trained firemen seldom are available at or near mining plants to teach the fundamentals of fire-fighting to local fire brigades, with the result that efficiency in combating actual fires is lacking. Often the attitude "it can't happen here" is held by the management of a mining property, unless the plant has suffered a serious fire; even then lapse of time is very likely to induce forgetfulness as to the possible hazards. The necessity for producing metals for the prosecution of this war has increased management's responsibility. Whereas heretofore the loss of a plant or mill by fire meant merely monetary less to the stockholder of the company, now the national interest is affected, in that the nation suffers from loss of production of minerals indispensable for war purposes.

Jan 1, 1943

By E. C. Baker

Costs of disposing of steel slag are estimated based on the present method and a proposed alternate method for a steel mill in the Pittsburgh area. Estimated cost data were calculated by the Bureau of Mines and do not reflect the investment and operating costs and credits of a specific steel mill and processing plant. The alternate method of steel slag disposal would result in an appreciable cost savings to the mill and concurrently supply the industrial and commercial markets with low-cost, high-quality construction materials.

Jan 1, 1970

By Scott Turner

We are here today to witness the graduation of 63 young men as Engineers in the mineral industries . It is an important occasion and one in which the public takes a keen interest , since this school has long been famous for the educational facilities it affords young men, and for the high professional standing of its graduates . : : : It is fitting that once each year we should pause to review the path the student has traveled , and to reflect upon the perspective opening before him as an engineer . I was invited to come from Washington to take part in this ceremony and to say something to these young graduates . In searching for a theme ," it occurred to me. that perhaps my best contribution would be to duscuss certain beliefs as to college training , deal with the situation in which the young engineer finds himself on graduation , touch on the new ideas of the social and political responsibilities of the engineer , and point out what he may expect to find in practice , and , above all , what he must do to orient himself properly in the mining profession and maintain the best traditions of our brotherhood . Let us first review your college days and see what they have done for you . I am told there are still many temptations in college . I know there used to be . Rest assured the same holds true in the professional life ahead of you. The main difference is , perhaps , that your greatest temptations in college were those offered by your teachers , who tried to entice you into realms of harder work, closer application , increased concentration , clearer thinking and better understanding , by animating your curiosity and increasing your powers of reasoning and of observation . In other words , here you have carefully and systematically been decoyed toward finer and loftier things . Do not expect that similar helpful influences will greet you on every side in your professional life . Often quite the contrary is the case .

Oct 1, 1930

By K. C. Dean

Fine-sized mineral wastes discarded by ore milling plants require stabilization to prevent air and water pollution. Stabilization has been attained by physical, chemical, vegetative, and combination procedures. Vegetative reclamation is preferred to physical and chemical stabilization but is diffi¬cult to achieve because the wastes are sterile, contain deleterious inorganic salts, and lack the essential nutrients and physical characteristics required for sustaining vegetative growth. Methods now have been developed for attain¬ing vegetative growth on all but excessively acidic, basic, or saline tailings at costs ranging from $120 to $650 per acre. The cost for stabilizing tail¬ings requiring more intensive treatment techniques may range upward to $1,750 per acre. This report summarizes procedures developed by the Bureau of Mines and industry for vegetating amenable tailings, lists costs for the various processes, and suggests procedures that may be applicable for stabilizing saline and pyrite-containing tailings. Ridged planting beds, drip irrigation, and deep-furrow planting techniques are suggested for stabilizing saline wastes. A combination of mill tailings and sewage sludge can be used for pro¬ducing synthetic soils, and layers of sewage sludge buried under a layer of tailings offer promise of inhibiting acid formation from oxidation of sulfides in mineral wastes.

Jan 1, 1974

By E. R. Palowitch

This report stems from a study by the Bureau of Mines of the possibility of reducing coal filter-cake moisture by applying radiant heat directly to the filter cake while under vacuum during the drying phase of the filter cycle. One disk of a 4-foot-diameter vacuum filter was equipped with gas-fired radiant-heat generators and the effect of radiant heating on the moisture content of a variety of filter cakes was studied. The results of this investigation show that this process can best be described as a filter aid capable of increasing the effectiveness of conventional filtration approximately 6 percentage points of moisture. The operating cost of removing water by this method is somewhat lower than the average operating cost of thermal drying and is considerably cheaper when the total cost is considered. Removal of water from coal that has been wet-cleaned is an important part of the overall coal preparation process. Water is a contaminant, and it is foolish to wash coal to reduce its ash content and add inert water in the process. In some instances the removal of water is actually more important than the removal of ash-forming minerals; its weight adds to the cost of transportation, and its evaporation during burning or carbonizing absorbs useful heat. Fine coal that contains more than about 10 percent moisture is notoriously difficult to handle. A problem thus exists for which there are sound practical and economic reasons to seek a solution.

Jan 1, 1961

By Richard F. Link

The principal procedures for the statistical analysis of gold assay and other trace-element data depend on applying either the normal frequency distribution or the lognormal frequency distribution. The consequences of applying both methods are examined through reference to example data from United States and South African gold mines. It is concluded that for estimation of average grades, except for certain data with a very high coefficient of variation (ratio of standard deviation to mean), use of the lognormal distribution is ordinarily undesirable because bias may be introduced and little efficiency can be gained. However, if biased average grades can be tolerated, as in the examination of data from surveys in exploration geochemistry, use of the log-normal distribution may be desirable. Various statistical analyses are detailed, and the tables presented to implement the analyses are more complete than those previously published.

Jan 1, 1971

By H. Dale Nichols

[The growing importance of the Sundence (Jurassic) formation an a source of oil, in the Rocky Mountain area has prompted the making of a series of porosity determinations of core samples collected. from the reservoir sands of the Lance Creek oil field, Niobrara. County, Wyo. These analyses are preliminary to a stud of fluid and energy relations in the Basal Sundance reservoir of that field, and the determinations of porosity will be used in subsequent studies requiring, calculations of the volumetric capacity of the reservoir and estimation of the reserves of oil and gas. However, the porosity characteristics an of the Sundance sands in the Lance Creek field are factory that affect the solution of many current practical problems of development and operation. Primarily for that reason but also because it is recognized that porosity values of different oil-production sands are of widespread interest throughout the industry, the results of the initial work have been presented in tabular and graphic form with no attempt to evaluate their significance as they relate to the production history of the field.]

Jan 1, 1938

By C. J. Walker

The Bureau of Mines undertook a theoretical and laboratory study to determine the feasibility of using ethylene as a tracer for natural gas in underground gas-storage reservoirs. The study indicated that ethylene was a useful gas tracer in underground gas storages. Tracer losses were not excessive. Laboratory tests were conducted at pressures as high as 500 psia in both wet and dry consolidated-sandstone cores, evaluating tracer loss with gas blends containing natural gas with different concentrations of ethylene tracer. Under certain conditions losses were less than 17 percent.

Jan 1, 1966

By Foster Fraas

This report describes the application of pulsed magnetic fields derived from alternating and intermittent magnetizing currents. Application of such pulsed magnetic fields to the matrix-type separator permits (1) the complete discharge of the magnetic fraction with wet feeds and (2) the dry separation at particle sizes down to 325 mesh. At smaller particle s indications are that frequencies above 60 hertz will be required. Applications of intermittent magnetizing current to the cross-belt separator give the cross-belt-separator an advantage over the conventional constant-field cross-belt and induced roll separators; the intermittent current enables the cross-belt separator to separate matted fibrous and magnetically coagulating feeds, a type of feed that occasionally occurs with mineral, industrial, and secondary materials.

Jan 1, 1973