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By Marvin L. Whisman

Several parameters controlling the reproducibility of tritium determina¬tion in organic compounds by liquid scintillation counting were evaluated by the Federal Bureau of Mines. These included optimum volume of scintillator solution for maximum counting efficiency, reproducibility of counting a sealed commercial standard and comparison with duplicate counts on laboratory-prepared samples. The error introduced by using microliter pipets, optical differences in counting vials, reproducibility of counting organic samples where quenching is a factor, reproducibility of counting laboratory-prepared samples with an added internal standard, optimum ratio of internal standard activity to sample activity, effect of sample volume upon counting efficiency, count rate at which coincidence losses become apparent, and reproducibility of organic compound radioassay by the standard addition technique are outlined. From the evaluation of these parameters, a technique that can be applied routinely to organic compounds containing tritium has been established, and details are included in this report.

Jan 1, 1961

By James S. Browning

Recovery of fine mica from a sample of impounded tailing from the Dixie Mines, Inc., crushing and screening operations, Heflin, Ala., was investigated to determine if plant losses of mica could be reduced while econmically producing a commercially acceptable mica concentrate. Conventional wet-tabling and agglomerate-tabling methods yielded concentrates assaying about 95 percent mica from the tailing that contained 17 percent mica. Products containing about 98 percent mica and accounting for mica recoveries of 86 percent were obtained by flotation, using as reagents sulfuric acid, kerosene, and coco amine acetate (a mixture consisting chiefly of dodecyl and tetradecyl amine acetates). The results of the batch flotation tests were verified by tests in a small continuous flotation pilot plant.

Jan 1, 1963

By McHenry Mosier

A skull breaker has demonstrated its advantages for secondary breaking in a limestone quarry by entirely displacing secondary blasting . It has reduced safety hazards to workmen, increased the number of quarry operating days , and has lowered mining costs by 2.7 cents a ton. It is believed that the application of the skull breaker can be made economically advantageous in the surface mining of other commoditics .

Aug 1, 1948

By Gary E. Sherman

Preliminary economic mining feasibility studies were conducted by the Bureau of Mines to estimate mining costs in the Juneau gold belt area of the Juneau Mining District, southeastern Alaska. Investigations were conducted on the economics of two mineral deposit types: (1.) Berners Bay vein gold deposits, and (2.) stockwork gold deposits containing gold, silver, and lead. Cost estimates were developed using the Bureau of Mines Cost Estimating System (CES). Discounted cash flow return on investment (DeFROI) was calculated using the Bureau's MINSIM computer program. Underground mining of a Berners Bay vein gold deposit was found to be economic (15 pct DCFROI) at a recoverable metal value of $353.67/mt for a 100 mtpd shrinkage stoping mine with a 10 yr mine life, $324.76/mt for a 20 yr mine life, $138.63/mt for a 500 mtpd longhole stoping mine with a 10 yr mine 1 ffe, and $127.50/mt for a 20 yr mine life. Block caving mining of a large stockwork gold deposit was found to be economic at a recoverable metal value of $15.28/mt for a 18,000 mtpd mine with a 20 yr mine life.

Jan 1, 2011

By G. E. McElroy

As one phase of a general program of enthracite mine-fire research initiated by the Bureau of Mines in September 1935, a study of the records of past fires was considered a necessary approach to a proper understanding of present and future fires because only limited information could be obtained directly from existing active fires on account of their inaccessibility. Through the courtesy of interested operators, all available records of fires that had occurred in a large group of steep-pitch anthracite mines in the Western Middle and Southern fields of the Pennsylvania anthracite district were examined and analyzed for data on the causes, costs, behavior, and control of fires, and this report is primarily a discussion of these factors based on a close study of these particular records. Mining Conditions The records pertain to a group of mines that have contributed about 12 percent of the total Pennsylvania anthracite production and constitute a large proportion of, and well represent, steep-pitch operations in this district. Throughout the area represented, the coal occurs as a series of up to 20 parallel seams in folded slate and sandstone strata and almost entirely on pitches of 400 to 80°, with vein thicknesses of 5 to 60 feet. Practically all are old mines with histories dating back to 1850, or thereabouts, and present operations are either under or adjacent to mined-out areas extending to surface or to the saddles of anticlines. All operations are at relatively shallow depths, that is, within 1,000 feet, vertically, of the surface. Mining methods are largely a heritage of the past and embrace typical breast and pillar operations with practically no mechanized mining and with the coal shot ?off the solid.? Most of the mines are rated as gassy and are operated now on a closed-light basis. Permissible explosives are now used entirely for breaking coal, and dynamites for rock work and chute-starting blasting.

Jan 1, 1938

By G. E. McElroy

The Coeur d'Alene minim, district of Shoshone County, Idaho, has been one of the largest and most active lead-silver producing districts in the United States for the last 40 years. The mines of the district enjoy exceptional natural advantages with respect to ventilation in that the veins apex high on mountain sides and are most often developed to considerable depths, up to 2,000 feet, by adit and crosscut tunnels under conditions that develop large natural draft pressures; the increase of temperature of the rock with increase of depth from surface in at a low rate; and the average surface temperatures are low. These natural conditions have, in the main, resulted in well-ventilated mines with low temperature conditions throughout. However, where the development has been carried to considerable depths below the lowest level of surface entry, natural-draft ventilation has proved inadequate, and mechanical ventilation systems have been installed on the three largest mines of the district. Local conditions, more particularly those in dead-ended working places, have also required auxiliary ventilation by will fan-pipe units in these and other mines. A particular feature of the district is the number of exceptionally long crosscut tunnels that have been driven to provide entry to vein systems from low points adjacent to milling and transporta¬tion facilities. Three of these tunnels are approximately 2 miles long, and lengths of 3,000 to 8,000 feet are quite common.

Jan 1, 1931

By Robert L. Anderson

A shaft or slope bottom is that portion of a mine that is contiguous to the bottom of the main hoisting shaft or slope. It includes the terminal tracks for loaded-and empty-car storage, locomotive run-arounds, locomotive shops, charging stalls, supply rooms, pump rooms, waiting rooms, and offices for dispatcher, weighmen, and foremen. This paper will deal principally with the arrangement of tracks and the handling of cars on the bottom, but includes other data that may be affected, directly or indirectly, by the bottom lay-out. All of the mines discussed are being operated in comparatively level coal seams.

Jan 1, 1937

By John W. Taber

Discovery of these unusual fluorite deposits was brought to the attention of the Bureau of Mines late in 1951, shortly after the first locations were made. A brief investigation of the deposits by the Bureau revealed seven principal outcrops of fluorite in two areas. The smallest outcrop continuously exposes massive fluorite over an area 25 by 55 feet; the largest outcrop is a similar exposure 180 by 240 feet. The deposits appear to be sharp-walled, low-angle-, tabular ore bodies in granite and are at least 10 feet thick. The Bureau investigation of the deposits included bulldozer strip-trenching, drilling and blasting rock cuts, and channel sampling across three of the largest outcrops. This sampling indicated an average grade of 97.2 percent CaF2 and 1.44 percent SiO2. Preliminary metallurgical tests on the ore indicate that it can be concentrated to acid-grade specifications by simple gravity methods. One laboratory test recovered 78.4 percent of the fluorite in a product containing 98.7 percent CaF2, 0.25 percent SiO2, and 0.10 percent Fe2O3.

Jan 1, 1952

By Henry E. Perlee

Air compressor explosions that are caused by the ignition of combustible vapor mixtures cannot be explained by a single reaction mechanism or sequence of events. Explosions have been caused by the sudden release of large quantities of lubricating oil, by the rapid vaporization of oil that had accumulated slowly in high-pressure piping, and by the production of decomposition products from carbonaceous deposits. Ignitions can be caused by the heat produced in a catalytic reaction, in a compression process, or when a shock wave is propagated through a combustible vapor-air mixture. The frequency of these ignitions can be minimized by establishing proper maintenance and cleaning schedules. Further study is needed to satisfactorily correlate the various factors involved in compressor explosions.

Jan 1, 1963

By T. E. Gray, A. W. Deurbrouck

This report describes the preparation characteristics of significant coalbeds in Kanawha County , W. Va . It is one in a series of Federal Bureau of Mines reports planned to determine coals suitable for producing metallurgical coke , either as mined or after beneficiation . Almost 9.4 million tons of coal was produced in Kanawha County , W. Va . , in 1959 , of which about 67 percent was cleaned mechanically in 10 cleaning plants . It has been estimated that more than 5,505 million tons remain in the county . Samples were collected from Pittsburgh , Stockton - Lewiston , Winifrede , Cedar Grove , Peerless , Upper Kittanning , Coalburg , Powellton , Eagle A , No. 2 Gas , and the Lower Kittanning beds . These beds were selected by the Bureau based on current production rates and estimated minable reserves . Float - and - sink tests of the samples collected from Eagle A , Peerless , Cedar Grove , Winifrede , and No. 2 Gas beds show that these coals at one location each are suitable for metallurgical use without washing . Lower Kittanning bed at four locations ; Pittsburgh , Stockton - Lewiston , and No. 2 Gas beds at two locations each ; and Coalburg , Powellton , Winifrede , Peerless , Upper Kittanning , and Cedar Grove beds at one location each can be upgraded to metallurgical quality by mechanical cleaning . Crushing the samples to 3/ 8- inch top size increased yields substantially at 1.30 specific gravity of Pittsburgh ( 17.5 percentage points ) and Upper Kittanning ( 13.0 percentage points ) beds and increased yield for the other beds sampled to a lesser amount . At this specific gravity , finer crushing caused In the 1.58 specific gravity float a general decrease in ash and sulfur . fractions of the other samples tested , most of the yields , and ash and sulfur contents , were lowered slightly by finer crushing .

Jan 1, 1963

By Jack I. Paige

The devitrification of lithium silicate glasses was studied to determine the effect of annealing temperature, composition, and additives on nucleation and crystallization. High-purity glasses, prepared from reagent-grade chemicals, had close to optical quality when prepared by a vacuum induction melting method developed during this research, The progress of devitrification was traced by differential thermal analysis and thermal expansion for those lithium metasilicate-silica compositions containing 80 to 90 percent silica. Microscopic studies of glasses partially devitrified at various temperatures and annealing times indicated that the primary initial mode of formation of individual crystals ,vas from densely crystalline zones that filled in as crystallization advanced Of the additives tested, calcium, potassium, and sodium helped promote devitrification with the least cracking or surface deformation. Tin oxide was most effective in reducing volume contrast ion during devitrification, but was not ClS effective in preventing cracking as calcium or potassium additions.

Jan 1, 1965

By R. J. Morrell

The Bureau of Mines conducted a series of laboratory experiments to test a cutting technique for hard rock using large-scale drag cutters. Cutting experiments were performed on rocks ranging in compressive strength from 10,000 to 27,000 Ib/in2, using large drag cutters from 3 to 6 in. in width. The tests were conducted on a special test apparatus, called a ripper tester, which made a curvilinear cut across the rock sample while measuring the cutting force acting on the drag cutter. The cutting method that evolved from these experiments is called ripper cutting, and its energy efficiency appears superior to all other large-scale mechanical fragmentation techniques. In addition, the method cre-ated very little dust, and the wear on the bits was negligible. A fragmentation system based on ripper cutting was then devised, and a large-scale test device was fabricated to allow full-scale laboratory testing of the system. The results of these tests will be published in future Bureau reports.

Jan 1, 1986

By T. A. Sullivan

Refining in a molten salt electrolyte was investigated as a means of recovering nickel containing less than 1 percent and preferably less than 0.2 percent cobalt from nickel products containing up to 5 percent cobalt. Electrolytic separation of nick and cobalt was accomplished in a molten KCl-LiCl-NiCl2 electrolyte. Nickel containing less than 0.10 percent cobalt was routinely prepared. Factors that influenced the transfer of cobalt to the refined product were the nickel concentration of the electrolyte, the cobalt concentration of the electrolyte, the ratio of nickel to cobalt in the electrolyte, and cathode current densities. A method of recovering the cobalt from the electrolyte was developed. The possibility of preparing high-purity nickel by this process was shown, as well as the preparation of various cobalt-nickel-tungsten alloys.

Jan 1, 1968

By E. G. Davis, H. P. LeVan, L. S. Smith

Leaching of a Georgia umber ore when using both ferrous sulfate and pickle liquor was studied in the laboratory . The ferrous sulfate content of the leach solution was the major factor affecting the extraction of manganese from the ore . Time , temperature , and the sulfuric acid content of the leach solutions had relatively little effect on leaching of manganese from the ore ; however , these factors did affect the amount of iron extracted from the umber and/or precipitated from solution . Simulated countercurrent leaching of the ore with pickle liquor containing 130 gpl (grams per liter ) ferrous sulfate ( 48 gpl ferrous iron ) produced a pregnant solution having 16 gpl manganese and 41 gpl iron . Filtration tests of the leach slurries indicated that separating the leach solution and solids by vacuum filtration was impractical , whereas pressure filtration was feasible when the cake thickness was limited to about three- fourths of an inch . Fired pellets of the filter cake yielded a firm , hard product analyzing 56 percent iron and less than 0.1 percent sulfur .

Jan 1, 1964

By David Burgess

Natural gas is a general term applied to the gas obtained from oil or gas wells. It is the most widely used of all gaseous fuels. The principal disadvantage in the use of this and other gaseous fuels is the difficulty encountered in the storage and transportation of large quantities in the gas state. Handling in the liquid state is possible, but reduced temperatures are required since methane (table 1) is the principal component of most natural gases that are used as fuels. Actually, liquid storage has been utilized both here and abroad;3 however, the Cleveland disaster4 has pointed out the need for a critical evaluation of the hazards involved in the storage of this cryogenic fuel. Accordingly, a program was undertaken to obtain basic data that could be used to assess these hazards. In this report, the factors to be considered in an evaluation of the fire and explosion hazards associated with any fuel are each discussed briefly. These factors are then used to assist in the design of experiments for the evaluation of the hazards associated with liquefied natural gas (LNG) relative to those associated with other common fuels. Experiments have been conducted on the vaporization of LNG, the mixing of LNG vapors with air, the effect of temperature and nitrogen dilution on the limits of flammability of methane in air, the burning rates of LNG and other fuels, flame radiation, and extinguishment of fires above liquid pools. Based on the results of these experiments, LNG can be stored safely in suitably designed above-ground tanks surrounded by earthen dikes in much the same manner as gasoline.

Jan 1, 1962

By Robert E. Barieau

In the design of plants to separate helium from natural gas, it is necessary to estimate the enthalpies of the various streams at various positions in the process. This Bureau of Mines report surveys the various methods that have been used to determine enthalpies and gives information on the organizations with such capabilities. The minimum information required for developing an enthalpy diagram is presented, and the relative merits of the various methods are discussed. It is concluded that methods that require no mass flow rate or energy measurements are to be preferred.

Jan 1, 1965

By Robert E. Barieau

In the design of plants to separate helium from natural gas, it is necessary to estimate the enthalpies of the various streams at various positions in the process. This Bureau of Mines report surveys the various methods that have been used to determine enthalpies and gives information on the organizations with such capabilities. The minimum information required for developing an enthalpy diagram is presented, and the relative merits of the various methods are discussed. It is concluded that methods that require no mass flow rate or energy measurements are to be preferred.

Jan 1, 1965

By E. V. Deshayes, W. E. Young

"INTRODUCTION The Camp Bird mine was investigated by Bureau of Mines engineers 3/ September 22 and 24, 1942, and April 29 and 30, 1944. In a subsequent report and supplement, it was recommended that core drilling be done below the 14th. level to determine if commercial ore existed at greater depths, and particularly if ore existed in the vein or adjacent thereto where it passes into the sedimentary formations estimated to underlie the volcanics approximately 400 feet below the 14th level.Seven diamond-drill holes aggregating 3,956 feet were drilled. Four of these holes were under the Hematite ore body and three were under the Big Discovery ore body. Two holes under, the Hematite ore body wore directed at angles but little steeper than the angle of dip of the vein and penetrated the sedimentaries beneath the volcanics close to the vein. Enough low-grade ore was found at the base of the Telluride conglomerate to indicate the presence of a large body of low-grade zinc sulfide ore. Two holes were directed to crosscut the vein at a depth of approximately 125 feet below the 14th level. No commercial ore was cut, but the vein showed the average width and same general characteristics as at the 14th level. One hole under the Big Discovery ore body was directed to crosscut the vein and test the base of the Telluride conglomerate in the footwall block. No commercial ore was found in either the vein or the sedimentary horizon. One hole was directed to test the base of the Telluride conglomerate in close proximity to the vein in the hanging-wall block. This hole was lost approximately 100 feet short of its objective, and a third hole was drilled to accomplish this same thing. The third hole was stopped approximately 50 feet short of its objective when failure of equipment caused a recess of the"

May 1, 1948

By L. M. Demers, D. C. Kuhn, N. El-Ayouby, C. F. Stanley

"Oxygenated metabolites of arachidonic acid (MJ are produced by the alveolar macrophage (AM) and have been shown to mediate inflammatory reactions. We therefore assessed the production of eicosanoids by AM harvested from the lungs of rats ex· posed to a bituminous coal dust for 2 wk in an inhalation chamber in order to determine if AA metabolism was altered in a manner that may promote an inflammatory response in the lung. Exposure to coal dust resulted in a 66% increase in the number of AM harvested, an increase in thromboxane A2 (TxA;i) and leukotriene 84 (LTB,j) production to 222% and 181% of control values, respectively, and a decrease in prostaglandin E2 (PGE:i) production to '62% of control values. In AM harvested from rats allowed to breath clean air for 2 wk following coal dust exposure, PGE2 production returned to control levels but TxA2 and LTB4 production remained elevated. The TxA2 synthesis inhibitor UK 38,485 reduced TxA2 production in dust-exposed AM both immediately and 2 wk following exposure. Thus, exposure of rats to coal dust significantly alters the metabolism of AA in AM, with potentially important aspects of AA metabolism remaining altered even after a 2-wk recovery period. Based on the established role of eicosanoids in inflammatory and fibrotic processes, these results suggest that the alteration of AM eicosanoid production as a result of the inhalation of coal mine dust may be an important factor in the pathophysiology of coal workers' pneumoconiosis.The authors are grateful to Joan Greenwood and Barbara Scheetz for their excellent technical assistance and to Brenda Pavone for the preparation of the manuscript. This research was supported by the U.S. Department of The Interior's Mineral Institute Program administered through the Generic Mineral Technology Center for Respirable Dust under grant 1135142.Request for reprints should be sent to Douglas C. Kuhn, Ph.D., Department of Pathology, The M.S. Hershey Medical Center, Hershey, PA 17033.INTRODUCTIONPulmonary alveolar macrophages (AM) are activated by foreign particles and microorganisms that enter the small airways (Kass et al., 1966; Herscowitz, 1985). This defensive reaction involves phagocytosis, lysosomal enzyme release, and the generation of reactive oxygen species by the AM (Snella, 1986; Rich et al., 1987). A number of agents, including phorbol esters, zymosan, adenosine diphosphate, organic hydroperoxides, and calcium ionophore, have been shown to activate the AM in vitro (Badger, 1986; Marshall and Lands, 1986; Snella, 1986). The AM response to these activators appears to be mediated in part by the oxygenated metabolites of arachidonic acid (AA) (Bertram et al., 1988; Demers et al., 1987; Mcleish et al., 1987).The AM may metabolize AA through cyclooxygenase- and lipoxygenase- catalyzed pathways to produce a variety of eicosanoids including prostaglandin (PG) E2, thromboxane (Tx) A2, leukotriene (LT) B4, LTC4, LTD4, and several hydroxyeicosatetraenoic acid derivatives (HETEs) (Willis, 1970; Camp et al., 1983; Poubelle et al., 1986). The production of these eicosanoids may enhance the. defensive ability of the challenged lung since they stimulate chemotactic cell recruitment to the site of invasion, enhance extravasation of circulating immune cells, and promote local vasodilatation. However, continued stimulation of the AM population, with the consequent production of proinflammatory eicosanoids, may ultimately enhance the disease process by contributing to chronic bronchoconstriction, fibrosis, and the persistent release of toxic oxygen species."

Jan 1, 1990

By John Dixon

This paper is one of a series on milling methods and costs being published by the Bureau of Mines. Acknowledgment is made to J. B. Tyrrell, managing director, and Wm. Sixt, manager of the Kirkland Lake Gold Mines, for permission to publish this article. The Kirkland Lake Geld Mining Co.'s mill is located on Government Road at the west end of the productive part of the Kirkland Lake mining area, 1 mile west of the village of Kirkland Lake. The crushing plant is connected to the shaft house of No. 2 shaft, which is now the only operating shaft.

Jan 1, 1931