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By D. Bienstock

The Fischer-Tropsch synthesis is practicable in a reactor where the exothermic heat of reaction is removed by circulating large quantities of recycle gas through a catalyst bed of high-voids content. At an hourly space velocity of 1100, the feed gas, a mixture of 1.5 parts hydrogen to 1 of carbon monoxide, was converted 90 percent, producing hydrocarbons predominantly in the gasoline range. At these conditions a recycle-to-fresh gas ratio of 40:1 was enough to give excellent temperature control with a pressure drop of 1.5 p.s.i. per foot of bed using a steel catalyst in the form of lathe turnings. Steel parallel plates, although offering lower resistance to gasflow, were less reactive and less durable. INTRODUCTION The Federal Bureau of Mines has been engaged in a research and development program since 1944 on the synthesis of gasoline from coal. Gasification of coal with steam and oxygen to yield a synthesis gas--a mixture of carbon monoxide and hydrogen--is being investigated at Morgantown, W. Va.; and the synthesis of gasoline by catalytically reacting the carbon monoxide and hydrogen over iron by the Fischer-Tropsch reaction is being investigated at Bruceton, Pa.

Jan 1, 1960

By Martin Hertzberg

The early and reliable detection of the self-heating of combustible substances in mines is of considerable importance to the mining community. This Bureau of Mines report describes the results of a variety of studies of incipient combustion and its detection. Heated samples of coal, wood, and various polymers were used to evaluate the relative sensitivities of several types of detectors. The laboratory results indicate that submicrometer particulate detection is the most universal and sensitive method. Carbon monoxide detection was as sensitive as submicrometer particulate detection for pyrolyzing coal but was relatively insensitive to pyrolyzing wood or plastics. The conventional type of ionization smoke detector was the least sensitive for coal and of intermediate sensitivity for wood and plastics. Self-heating experiments with Pittsburgh seam coal piles of varying particle sizes gave ignition temperatures of 170° C for 4-to 7-µm dust, which increased monotonically with particle size. The measured heating rates were compared with data from an adiabatic calorimeter to obtain preexponential rate constants. The preexponential rate constants varied linearly with the surface area per unit mass of sample as would be expected for heterogeneous surface oxidation. The propagation behavior of ignition waves and the overall self-heating appears to depend critically on the magnitude of the convective flows induced, which counteract the depletion of oxygen in the void spaces of the pile. Classical theories of thermal ignition require substantial modification to be applied reliably to such cases.

Jan 1, 1977

By F. E. Armstrong

A program with the objective of developing a fast, accurate instrumental method of analyzing mine dust for incombustible content has been underway in the Bureau of Mines for several years. Several prototype instruments making use of a gamma-ray backscatter technique have resulted. Although extensive laboratory testing has shown that these instruments are accurate under laboratory conditions, only extensive field testing will prove their ultimate practicality and usefulness. This report shows that under most conditions these devices are at least as accurate as the volumetric method and much faster in use. Other data obtained during the same study concerning mine dust are presented; these concern moisture content, sample bulk density distribution, and some particle size distribution information.

Jan 1, 1973

By J. Bruce Clemmer

[Gypsum is one of the mo .. t iJf.l)ortant nonmp.tal1.ic T!1inerals, as is indicat-? ed by the fact that tlle Uni ted states cO!1sUl:Ied p, roximn..tely 3,500,000 tons of natura.l and calcinecl e::,j;-psum in 1937. The b\.'.ilr:.in.; traces \"fe.ro the largest users and required 2,520,000 tons of calcine for the r-roductiop. of plaster,]

Jan 1, 1941

By Larry J. Nicks

The Bureau of Mines is investigating the catalytic activity of rare-earth compounds to develop a catalyst for the cathode reaction of a hydrogen-oxygen fuel cell. This report presents the results of studies of the catalytic activities of lanthanide oxides for the oxidation of hydrogen at 150° to 250° C. Preliminary activity tests were made with approximately stoichiometric mixtures of hydrogen and oxygen diluted with helium. A series of tests was also run under oxygen-rich conditions in which specific rate constants and activation energies were determined. Variations in rate constants up to 2,000 times were observed for the various lanthanide oxides. The three most active catalysts were oxides of Ce, Pr, and Eu, having specific activities of 6.93 X 10-7, 4.88 X 10-7, and 4.06 X 10-7 moles H2.sec-1.m-2, respectively, at 200° C.

Jan 1, 1973

By R. G. Sandberg

The Bureau of Mines investigated a hydrometallurgical procedure to recover gold, silver, and byproduct lead from a complex lead-zinc sulfide ore. A ferric chloride (FeCI3) preleach, at 40° C in 6 h, extracted about 50 pct of the zinc and formed insoluble silver and lead chlorides. Subsequent acid thiourea leaching, for 1 to 3 h at 40° C, extracted about 85 pct of the gold and silver. Lead chloride was solubilized from the remaining residue with NaCI brine solution at 55° C in 1 h. Lead metal was recovered from the brine solution in an electrolytic cell with an anion perms elective membrane at a current efficiency of 95 pct and current density of 100 A/m2. Spent FeCl3 leach solution was reoxidized in the anode compartment at a current efficiency between 75 and 95 pct.

Jan 1, 1986

By F. E. Block, Robert R. Brown, A. W. Henderson

The chlorination of Cr₂ 03 (chromic oxide ) in the presence of carbon with CC14 (carbon tetrachloride ) and COCl2 (phosgene ) chlorinating agents was investigated by employing the radioactive tracer carbon By tagging carbon mixed with Cr₂ 0з , the chlorination reaction was evaluated in terms of the competitive reaction of the elemental carbon and the carbon contained by the chlorinating agent . A unique gas - analysis train was used to separate the chlorination product gases ; CO , CO₂ , and COC12 . The C¹ activity of the gases was determined and used to calculate the reactivity of each source of carbon . Reactivities were determined for the temperature range from 600 ° to 900 ° C. The results of the investigation show that each source of carbon reacts significantly with the Cr2 03 and that the reactivity of each form of carbon depends on the reaction temperature , and each form is independent of the other . Radioisotope and gas - analysis techniques are discussed and a description of the experimental apparatus is given .

Jan 1, 1964

By J. M. Mutmansky, C. Lee

"IntroductionRecognition of Coal Workers' Pneumoconiosis (CWP) as a major occupational disease has affected various aspects of the coal mining industry in the United States as well as in almost all major coal producing countries, Regulations related to the control of coal mine dust forced mine operators to modify their mining and ventilation practices. As the coal production record of the last 15 years shows, this had both direct and indirect impacts on the productivity and production costs.To identify the causes of CWP, many research efforts have been made throughout the world. Most of these studies were epidemiological in nature, attempting to pinpoint exposure and seam variables that affected the incidence of the disease. Other studies have been oriented toward the elemental and mineralogical composition of the coal dust in the mine atmosphere and in the miners' lungs. These studies indicate that there may exist some relationships between the characteristics of the coal mine dust and the prevalence of the disease. Some of the variables that are thought to affect the occurrence of CWP are the mass of the dust in the working place, the rank of the coal, the existence of certain trace elements, the free silica content of the coal, and the existence of other minerals in the respirable dust. A more complete description of these previous research studies has appeared elsewhere (Mutmansky and Lee, 1984).The behavior of particles in the human lung is known to be governed by their aerodynamic diameter, which is defined as the diameter of a hypothetical spherical particle with unit density that exhibits the same settling velocity as the given particle. Because of this fact, the aerodynamic size distribution of coal mine dust is one of the parameters to be determined along with the other physical, elemental, and mineralogical characteristics. The objective of this paper is to establish a strategy for providing coal mine respirable dust samples for characterization purposes using instruments that classify according to the aerodynamic diameter. In addition, several findings concerning characterization methods will be presented"

Mar 1, 1989

By H. D. Jacobs

A process for recovering both iron and manganese from four manganiferous ores of the Cuyuna Range was evaluated. It comprised: (1) Low-temperature gaseous reduction to convert nonmagnetic iron minerals to magnetite and manganic minerals to manganous oxide, (2) acid leaching to extract manganese, and (3) magnetic separation to reclaim iron from the leach residue. Iron recoveries from the magnetic products ranged from 70 percent to 90 percent; manganese recoveries from leach filtrates ranged from 75 percent to 95 percent. Two ores, from the Hillcrest and South Alstead properties, yielded magnetic products considered adequate for use as blast furnace feed. Although good yields of manganese were attained on all ores, appreciable iron accompanied the manganese into solution. Previous work, however, has shown that this iron can be precipitated almost quantitatively under autoclave oxygen pressure with very little loss of manganese.

Jan 1, 1970

By Lincoln A. Stewart, P. S. Haury

"INTRODUCTION AND RESUME Arizona asbestos mines are the only sources on the American continents of iron-free chrysotile spinning fiber that meets the Navy specifications for asbestos fiber for use in covering electrical cables. Rhodesia normally supplies the bulk of this grade of asbestos at about half the Price of Ari zona spinning fiber. The acute submarine menace in 1942 focused attention on the danger that imports might be cut off and that a sudden demand for greatly expanded production might fall on the Arizona mines to supply the tonnage of this essential material needed for war production.A joint preliminary investigation of Arizona asbestos deposits was made in August 1941 by J. R. Thoenen, senior mining engineer of the Bureau of Mines and A. E. Granger, a geologist of the United States Geological Survey. A more extended investigation of the numerous asbestos mines and prospects, which are scattered over 25 townships of difficult terrain in Gila County, was begun by the senior author in August 1942.The Geological Survey assigned two geologists (Newton Chute and A. F. Shride) a few weeks later to study the geology as an aid in selecting the mines for the Bureau's exploration projects. Six mines were selected for exploratory work because it was desired to prove reserves of ore where production could be started quickly if urgent demand should arise. Acceleration of production is normally slow because of adverse operating conditions. First, the mines are at distances of 35 to 100 miles from Globe, the shipping and supply point, and the roads are few and poor. The mine openings start in steep canyon walls, so that mining supplies usually have to be packed in and the product packed out over 0.5 to 5 miles of burro trail. Second, most of the ore deposits are small, and the ratio of rock broken to spinning fiber recovered is very high, usually exceeding 200."

Aug 1, 1947

By A. E. Schwaneke

Plans and specifications are given for constructing a quartz composite oscillator designed to measure internal friction in metals and alloys . The characteristics of the system are listed , and detailed procedures for its operation are explained . Typical measurements on manganese - copper alloy , on single - crystal magnesium , and on polycrystalline magnesium are shown to illustrate applications of the system .

Jan 1, 1964

By E. R. Cole

This Bureau of Mines investigation was prompted by the need forr a stable anode for electrowinning metals, particularly zinc and copper, from acid solutions. The polarization behavior of Pb-Ag (1 pct Ag) anodes in H2SO4 and fluoride solutions was determined as the first step in the development of such an anode. A Luggin capillary, dc power supply, high-impedance voltmeter, and other equipment standard to an electrochemical laboratory were used in this study. It was determined that during polarization, a relatively hard, stable coating of Pb02 was formed on the surface of the lead-silver anode and the rate of formation of this coating was considerably enhanced by the presence of fluoride ions in solution. Subsequent investigations at the Bureau of Mines Rolla Research Center resulted in the development of a Pb02-coated titanium (Pb02-Ti) anode. Results of this effort were presented in Bureau of Mines Report of Investigations 8111. Additional data resulting from extensive testing of the Pb02-Ti anodes, as well as process improvements and innovations, are included in this report. The anodes were considered generally unsatisfactory for zinc electrowinning because of lower conductivity, higher oxygen overvoltages, and shorter in-cell life as compared with the Pb-Ag anodes now being used in industry. However, the PbO2-Ti anodes were used successfully to oxidize waste chromium solutions and to electrowin copper.

Jan 1, 1981

By Francis Church Linxoln

"This property was explored as part of a general investigation of zinc-prodccing areas of southwestern Wisconsin at a time when an effort was being made to increase the production metals important to the Nation's war program. This report describes the work that was done and presents the data obtained.ACKNOWLEDGEMENTSIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the and that they make the greatest possible contribution to national security and economy. It is the policy of the bureau to publish the facts developed by each exploratory protect as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, P., G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. R. S. Dean, assistant director. Special acknowledgment is due Professor G. H. Pett, of the Wisconsin Institute of Technology at Platteville, Wis., Jack Tracy, manager of the Mifflin Mining Co., and J. M VanMatre, representative of the Defense Property, for their assistance in the work. Acknowledgment is also due to A. F. Agnew and A. V. Heyl, geologists of the Federal Geological Survey, for furnishing geologic interpretations and lithologic studies of the drill-hole sections. All drilling was done under the immediate supervision of Francis C. Lincoln and M. Howard Berliner, project engineers, Edward P. Barrett, district engineer, Minneapolis, and E. D. Gardner, regional engineer, of the Bureau of Mines."

Sep 1, 1946

By W. D. Mcmillan

During the fall of 1943 the Bureau of Mines put down four churn-drill holes totaling 435 feet of bore at the McGregor zinc lead mine near Potosi, Washington County, Mo., after the property had been examined by John Soule, an engineer of the Bureau, in the fall of 1942. A small production of lead and barite ore had been maintained at this property for many Years from shallow deposits in residual clays. A few shafts had penetrated the underlying dolomites and exposed a network of narrow fractures containing galena, sphalerite, barite, and marcasite. The drilling by the Bureau tested conditions at depths ranging from 80 to 130 feet. This report sets forth the data resulting from the work.

Jan 1, 1948

By J. R. Ross

The extraction and recovery of nitrate from waste solutions generated in the production of titanium were investigated using solvent extraction techniques. Laboratory studies and continuous tests in a small solvent-extraction system showed that up to 98 percent of the nitrate can be selectively extracted by a solution of tributyl phosphate in kerosine. The extracted nitrate can be recovered as nitric acid, at concentrations suitable for reuse, by stripping the loaded organic with water.

Jan 1, 1973

By Martin J. Gavin

The oil- shale studies of the Bureau of Mines , conducted in cooperation with the State of Colorado and the University of Utah , have for their primary purpose the determination of retorting and refining conditions most favorable for obtaining the highest yields of most satisfactory products . Oil shales , typical of the deposits in several States , are retorted in carefully controlled retorts of differe types , the conditions being varied in successive runs as the results indicate that improvement in the yield and quality of the products most desired may be expected . Each shale presents a somewhat different problem , for it has been found that different shales treated under similar conditions yield products of different natures , and also that the same shale will yield products of different natures when retorted under different conditions . Some shales apparently can not be made to yield , under any set of conditions , products of so high an order as are yielded by other shales . This indicates that the oil -yielding materials of certain shales differ in constitution and in their manner of breaking down when undergoing destructive distillation . Other shales appear to contain oil - yielding materials that resemble each other closely as regards chemical constitution , yet they require some. what different conditions of treatment , if products of similar nature are to be produced from each . In such cases the controlling factors seem to be the richness of the shale that is , its content of oil -yielding material and the physical and chemical nature of its mineral parts .

Mar 1, 1922

By A. R. Mumford

During the course of an investigation conducted by the fuel section of the Bureau of Mines , on a hand- fired return- tubular boiler plant , it was found that the average cost of fuel to produce 1,000 lb. of steam was $ 0.5287 . Tests conducted after some simple changes had been made in the furnaces , and in the control of the boilers , showed the previous high cost of fuel per 1,000 lb. of steam could be reduced to the reasonable figure of $0.3540 , or the equivalent of over 30 per cent saving in fuel cost .

Mar 1, 1923

By Raymond L. Carpenter

The thermal conductivity, electrical resistivity, and Seebeck coefficient for nine compounds, based on the formula for enargite Cu3AsS3, were measured in a search for efficient materials to be used in thermoelectric generators or refrigerators. Results indicate that one of these compounds, Cu3SbSe4, has thermoelectric properties approaching those of bismuth telluride. An investigation of the effect of adding small quantities of tellurium to Cu3SbSe4 and Cu3SbS4 in order to improve their properties also was made. A figure of merit of 2.1 x 10-4 °C-1 was obtained for Cu3SbSe4 + 0.1 percent tellurium.

Jan 1, 1963

By Alan G. Mayton

Exposure to whole-body vibration (WBV) and the postural requirements of the job have been identified as important risk factors in the development of musculoskeletal disorders of the back among workers exposed to a vibratory environment. This paper focuses on preliminary results of WBV data collected for two groups of haulage trucks ? four older trucks from manufacturer A (MFR-A) and two newer trucks from manufacturer B (MFR-B). All of the trucks and their respective seats were considered to be in good working order during the study. Measurement periods for the truck groups had similarities, but varied from 2 to 58 minutes. Sampling times for the older trucks included a mean of 19.5 minutes and a standard deviation (STD) of 6.5 minutes compared to a mean of 40.8 minutes and a STD of 12.1 minutes for the newer trucks. Data collection coincided with the approximate delivery and first operation of the new trucks, and occurred approximately 12 months apart under similar weather and road conditions, and with the same drivers except an additional driver was included with the older trucks. Truck routes were somewhat different in that quarry production had changed location in the time between data collection activities. Overall, the results suggest that the newer trucks may provide better overall isolation to drivers/operators from WBV exposure compared to the older trucks operating at the quarry; although, this will need to be confirmed with additional measurements. Considering the higher variability and shorter sampling times for the older trucks, the results should be viewed with caution. For two of seven trials, the older trucks showed that seats amplified vibration, i.e., a transmissibility (T) >1.0. Seat T for the older trucks ranged from 0.31 to 1.17 with a mean of 0.77 and STD of 0.32. This contrasted with the newer haulage trucks where seats amplified vibration in 3 of 8 trials. In this case, T did not vary greatly and ranged from 0.87 to 1.05 with a mean of 0.97 and STD of 0.07. Regarding older trucks, in five of seven trials, the seat (output) data of weighted root-mean square (RMS) acceleration (wRMSZ) for the dominant z-axis exceeded the action level of 0.5 m/s2 action level recommended by the European Union Good Practice Guide for WBV (EUGPG) and levels exceeded the recommended exposure limit of 1.15 m/s2 in two of the seven trials. The wRMSZ values for the older trucks varied from 0.41 to 1.83 m/s2 with a mean of 0.99 and STD of 0.57. Similarly, newer trucks indicated a narrower range of wRMSZ from 0.38 to 0.95 m/s2. The mean wRMSZ was lower for the newer trucks at 0.58 m/s2 with a STD of 0.23 m/s2. Similarly, newer trucks indicated wRMSZ reached or exceeded the action level in four of eight trials. None of the trials with the new trucks showed wRMSZ levels that reached or exceeded the recommended 1.15 m/s2 exposure limit. As an indicator of driver/operator discomfort, overall weighted total RMS acceleration (vector sum) values seem to show a ?rougher? ride for the older trucks. The vector sum values for these trucks ranged widely from 0.70 to 2.59 m/s2 and, in four of seven trials, showed levels greater than 1.40 m/s2. The mean vector sum was 1.44 m/s2 with a STD of 0.75 m/s2. Comparatively, the newer trucks exhibited less variation with a range from 0.69 to 1.59 m/s2. The mean vector sum was 1.02 m/s2 with a STD of 0.35 m/s2. Vibration dose values for the dominant z-axis (VDVZ), gave a sense of vehicle jarring/jolting conditions. All trials with the older trucks were within the recommended EUGPG action level of 9.1 m/s1.75. On the other hand, in three of eight trials, both newer trucks exceeded this action level with values of 9.18, 12.58, and 13.21 m/s1.75. Neither truck group showed VDVZ that exceeded the exposure limit of 21 m/s1.75. A statistical analysis was not conducted, since the differences reported between truck groups may not be statistically significant owing to the relatively small sample size. Road conditions, changes in the truck routes, and driver/operator differences (e.g., stopping and turning) are possible factors in the higher VDV for the newer trucks.

Jan 1, 2008

By W. W. Adams

"During the calendar year 1925 the Bureau of Mines received from the operators of several hundred mines and quarries complete accident records covering deaths, permanent disabilities, and “lost time” temporary injuries. Some of the companies, - those that participated in the National Safety Competition-also furnished information showing the number of man-hours of work performed during the year. With these two types of information it was possible to calculate the accident-frequency and accident-severity rates of the different plants. Complete and comparable reports of accidents and Man-hours of “exposure” were received from 34 underground metal mines, 59 underground coal mines, 15 underground mines producing other nonmetallic minerals, and 102 open quarries or open-pit mines. The figures in the table appended to this report show the accident severity rates and other data for each of the 34 underground metal mines and for the group as a whole. It is proposed to publish similar figures for the other classes of mines and quarries at an early date.The 34 metal mines listed in the table are situated in Arizona, Idaho, Kansas, Michigan, Minnesota, Missouri, New Jersey, New Mexico, Oklahoma, South Dakota., and Utah; they employed 5, 925 men, an average of 174 men per mine, including employees above-ground as well as underground. With but few exceptions, 50 men was the minimum number of employees in any mine. The total period of employment or “exposure” at the 34 mines was 14,612,607 man-hours, an average of 2,466 hours per man, or the equivalent of 308 work-days of eight hours for each employee. Accidents resulted in 15 fatalities, 9 permanent disabilities, and 1,950 temporary “lost time” injuries (causing disability exceeding remainder of shift). The fatal and nonfatal injuries represented 132,575 days of disability. Thus the accident frequency rate for the group was 135 accidents per million hours and the accident severity rate was 9.073 days lost per thousand hours of 1 “exposure”. The severity rates ranged from 0.227 to 88.653, while the ·range of the accident-frequency rates was from 16. 6 to 307 .4. In compiling the accident severity rates shown in the table, all accidents caused by explosives were weighted at twice the number of days actually lost, as one of the purposes of the National Safety Competition was to stress the prevention of accidents caused by explosives."

Sep 1, 1926