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By Glenn E. Johnson

The Bureau of Mines investigated the production of hydrogen cyanide by reacting powdered coal (minus 300 mesh) with ammonia at 1,250° C in a bench-scale study. Both metallic and ceramic reactors were used. Yields up to 0.7 cu ft of hydrogen cyanide per cubic foot of ammonia consumed r- obtained. The resulting ammonia conversion of about 75 volume-percent approximates conversion obtained commercially in processes utilizing natural gas and platinum catalysts. The coals that had higher volatile-matter contents gave the best yields of hydrogen cyanide. Allowing the coal to adsorb ammonia before reaction resulted in increased yields of hydrogen cyanide. Cost studies for a plant with a 40-million-pound-per-year capacity indi-cate that hydrogen cyanide can be profitably coproduced with carbon black, from coal and ammonia, at the current market price of hydrogen cyanide (11.5 cents/lb). These figures are based on heating the reactor electrically. If a cheaper heating method were devised the economics of the process would be more favorable.

Jan 1, 1967

By V. F. Parry, J. B. Goodman, W. S. Landers

"This investigation was conducted: under the direction of A.C. Fieldner, chief, Fuel and Explosives Branch, Bureau of Mines, Washington, D. C. The following members of a Technical .advisory Committee were helpful in advancing the investigation: L. C. Harrington, dean, College of Engineering, University of North Dakota; D. F. Pane, president, Sheridan-Wyoming Coal Co.; Carson W. Smith, president, Consolidated goal & Coke Co.; Durbin van Law, consulting, engineer, Denver & Rio Grande Western Railroad; and C. B. Carpenter, professor of metallurgy, Colorado School of Mines. Coal samples from the Northern Colorado field used in the stoker during 3 years of service were supplied through the cooperation of N. C. Brooks, secretary, Northern Colorado Coals, Inc.This report describes the development and practical tests made on a small stoker-fired system for heating service water automatically. The system was designed to take advantage of the favorable reactivity of low-rank fuels, and the objective was to devise a combination of stoker, heat-receiving, and hot-water storage system Which would be automatic for at least 30 days without attention, while heating service water at minimum cost. The system was developed to a point where coal consumption was less than 10 pounds (or less than 100,000 B.t.u.) per day. The total operating cost of hot water for an average-family-was about $1.00 per month, with coal retailing at $6.00 per ton and electric power at 4 cents a kilowatt-hour. The heating system was designed for the utilization of low-rank fuels, but the general features of the double-tank system can be 'employed fuels, either gas or liquid fuels.The Subbituminous Coal and Lignite Section of the Bureau of Mines began investigations on the utilization of low-rank fuels in domestic appliances during 1939. Tests were made on various devices to find out if they were suitable for the low-rank fuels. Most of the available appliances for burning coal have been designed for the higher-rank fuels, and they are not well-suited for burning the lower-rank coals at maximum efficiency, because subbituminous coals and lignite have high bed moisture ranging between 20 and 40 percent by weight, which lowers heating value to the range of 10,000 to 6,500 B.t.u. per pound. They are noncoking, and the ash content ranges between 4 and 6 percent, with a fusion temperature of about 2,0000 F."

Jun 1, 1946

By Heine Kenworthy

"INTRODUCTION In 1930 the Shenandoah-Dives Mining Co. near Silverton, Colo., put into operation a newly erected, 300-ton selective flotation plant to mill complex ores from its nearby mine. The operation was a steady producer and was enlarged to treat 600 to 800 tons a day. In 1942 the company opened and started milling an area in the mine containing semioxidized ore. The valuable mineral content of this ore was considerably higher than in, the straight sulfide ore previously handled alone. The mixture of clean sulfide and semi-oxidized ore was difficult to treat; consequently, tailing losses, especially with respect to lead, were high. A few years later, in order to study the possibilities of obtaining higher recoveries by a modification of the mill flow sheet, a 1,200-pound sample of mill, feed, taken over a period of several days by the company, was submitted to the Mississippi Valley Experiment Sta¬tion for testing-. Although this sample proved to contain more than twice as much lead as the average yearly mill feed, the same problem of recovering the oxidized values was present.A résumé of the ore-dressing treatment used in the Shenandoah-Dives mill follows. After crushing, the ore passes through a ball mill, the minus 5-mesh discharge of which is distributed to three tables. A finished lead concentrate is made on the tables, and the table tailing goes to the classifier which is in closed circuit with the ball mill. The classifier overflow is treated -by flotation to obtain a bulk sulfide concentrate at a relatively coarse size. The bulk concentrate is thickened and reground to about 95 percent minus 325-mesh before flotation treatment to separate a lead-copper and a zinc concentrate. A typical monthly average showed that the table concentrate contained about 45 percent lead, 1 percent copper, 4 percent zinc, 12 ounces of gold, and 40 ounces of silver; that the lead flotation concentrate contained '35 percent load, 6 percent copper, 7 percent zinc, 3.5 ounces of gold, and 50 ounces of silver; and that the zinc flotation concentrate contained 2 percent lead, 0.5 percent copper, 60 percent zinc, 0.15 ounces of gold, and 4 ounces of silver. Recoveries in salable products were roughly b5 percent of the lead, 70 percent of the copper, 45 percent of the zinc, 85 percent of the gold, and b5 percent of the silver."

May 1, 1948

The Department of Interior, U.S. Bureau of Mines performs the task of estimating the quantity of coal reserves existing in each state on a county by county basis. As a part of Information Circular 8655, the Bureau of Mines established the criteria for the uniform estimations of coal reserves and listed the most recent estimates of coal reserves by county and by seam. At the same time however, the Bureau recognized that these figures represented the upper bound with regard to the estimated actually usable or obtainable reserves. Recovery of these reserves are subject to the mining methods used and to the resolution of such problems as the use of poor quality coal and competition provided by conflicting land use. These problems, in practice restrict the recovery of the estimated quantities of coal reserves listed in IC 8655. Another impact, the subject of this manual, is the impact resulting from previous mining activities. In particular, many of the reserve seams included in the reserve estimates overlie or underlie mined-out coal beds. Portions of these reserve seams may therefore be unmineable or at best may have a reduced quantity of extractable coal. In order to improve the accuracy of the coal reserve base estimates, the Bureau of Mines funded an effort1 to develop a systematic methodology for estimating the coal loss associated with the impact of previous mining activity. The coal loss calculation model (CLCM) described in this manual is a result of that effort and addresses the percentage of coal loss in reserve seams due to previous overmining or undermining.

Jan 1, 1976

By X. B. Starnes

"INTRODUCTION The Eva Tanguay property is in Crittenden County, Kentucky, about 1 mile south or the village of Mexico, and can be reached from Marion, the County seat, by travellng south on State Highway 91 for 6.8 miles and then turning southwest on State Highway 70 and traveling 2 miles farther.Although the property lies between the Huffaw and Pigmy properties, which together have produced 200,000 tons of fluorspar ore, production from the Eva Tanguay has been estimed at only 1,000 tons. Geological factors on the property indicated the likelihood of an ore occurrence, and the author examined the property in April 1944. Shortly thereafter, the U.S. Geological Survey wrote a report on the property, which was not published. A drilling program was initiated by the Bureau of Mines November 1, 1944, and continued until eight holes totaling 3,137.5 feet were drilled.The holes showed that the Tubb fault system on the Eva Tanguay property is composed of three members, all of which contained commercial ore. The line dividing the Haffaw and Tanguay properties crosses the vein outcrops, causing a part of the ore indicated to be on each property.The mineral rights, which are leased by Robert Frazer of Marion, are owned by Mrs. O. S. Denny and W. C. Bohn, both of Marion."

May 1, 1947

By P. L. Sibrell

Electrorefining of Ti in nonaqueous solvents has been studied by the U.S. Bureau of mines as a method for recycling impure scrap Ti. Electrochemical behavior of Ti species was investigated using cyclic voltammetry. Research results showed that Ti metal can be dissolved in polar solvents such as dimethylformamide or dimethyl sulfoxide. However, deposition of Ti from these solvents was not successful. Several solvent systems were investigated for electrodeposition of Ti but no deposits were obtained. Reduction of Ti4+ complexes to Ti3+ proved to be straightforward, but reduction to lower oxidation states could not be confirmed. In dimethylformamide solutions, cyclic voltammetry results demonstrated the reduction of Ti to an oxidation state of less than three, but no Ti metal was identified. In dimethyl sulfoxide solutions containing LiCl, it was possible to deposit Li metal. After adding Ti salts to the solution, electrolysis quickly passivated the electrode. Deposition of Ti was also investigated in solutions of dimethoxyethane and propylene carbonate but, again, no reduction of Ti to oxidation states of less than three occurred. Therefore, the prospects for a nonaqueous electrorefining system for Ti metal do not appear promising.

Jan 1, 2010

By August J. Kwitowski

The U.S. Bureau of Mines developed and tested a teleoperating system to control a new highwall mining system. A remote operator was provided out-of-sight sensory information and control of coal extraction and haulage equipment. Surface and production testing proved that the teleoperating system supplied the operator with sufficient sensory information to operate the mining system. Details on the teleoperating system provided in this report include (1) sensor selection, (2) a description of the electronic control system, (3) equipment selection and modifications, (4) the positive test results, and (5) recommendations for system improvements.

Jan 1, 2010

By Michael S. Miller

In 1984, at the request of the Bureau of Land Management, the U.S. Bureau of Mines studied the 34,050-acre Cow Creek Wilderness Study Area (WSA) in order to evaluate its mineral resources. The WSA, located about 60 miles southeast of Havre, MT, contains sandstones, shales, clays, and coal of Cretaceous age. The Cretaceous rocks have been intruded by ultramafic diatremes. Quaternary glacial, stream, and landslide deposits overlie the older rocks. Claims are staked at five of seven sites favorable for diamonds within the WSA and at additional sites nearby. Although the ultramafic diatremes within and near the WSA contain minerals that are indicators for diamonds, no positive evidence of diamonds was found during this study. An abandoned coal mine, the Shellenberger, is inside the southwest boundary of the WSA. Possible petroleum and natural gas at depth are currently of interest; land within the WSA is leased or under lease application for oil and gas. The WSA contains subeconomic clays, zeolites, gold, silver, platinum group metals, and coal.

Jan 1, 1986

By John Campbell, E. S. Baker, G. W. Jones

"INTRODUCTION In previous reports 5,6./ results were given showing the amount of natural ventilation that takes place in manholes (capacities, 74.1 to 308 cubic feet) when the number of ventilation openings in the manhole cover ranged from no openings to a maximum of 4g.The tests warranted the general conclusion that the ventilation or air changes taking place in, a manhole increase as the area of openings in the cover of the manhole is increased, and are proportional (with the exception of a few erratic tests) to the area of the openings in the cover. The area of the openings was the chief factor that affected ventilation.The results did not show any marked change in rate of ventilation due to increased capacity or shape of manhole, when the results were expressed in terms of air changes per day versus area of ventilation openings in square inches per 100 cubic feet of manhole space.It was observed during these investigations that in certain tests that showed erratic results (that is, did not agree with the general average for a given set of test conditions) the wind velocity during the test period was also abnormal. In view of these findings it was decided to conduct a series of tests in which the wind velocity across the openings in the manhole cover could be controlled accurately to determine the effect of wind velocity on ventilation rate."

Aug 1, 1938

By E. C. Lane

During the past 15 years the Bureau of Mines has made and published several hundred analyses of typical petroleums and has developed a system of interpreting the analyses and of classifying crude oils. In describing crude petroleum frequent reference is made to the "base" of the oil, a usage the petroleum industry has found convenient. As part of its general study of the characteristics of crude oils, therefore, the Bureau of Mines has developed a system of classifying them according to "base." This system as first published in 1927 was limited to four classes and in its original form is no longer considered adequate. Since the system was first published the Bureau has analyzed a large number of crude oil, including representative samples from nearly every important producing field in the world, and has found that the system of classification could be revised and amplified to advantage. The revised system is presented herein.

Jan 1, 1935

By J. M. Kuchta

Experimental data are presented on the autoignition temperature (AIT) characteristics of the hydrocarbon jet fuel, JP-6, in various oxygen-nitrogen atmospheres under conditions of constant volume and constant pressure. AIT's of this fuel in air varied little with fuel injection pressure but increased greatly with decreasing fuel content at low fuel-air-ratios. They also increased with decreasing oxygen content of the fuel vapor-oxidant atmosphere. Consistent with thermal ignition theory, the ignition temperatures increased with decreasing initial pressure, ignition delay, and vessel radius; expressions are given which define the observed variation of AIT with these variables for JP-6 fuel vapor-air mixtures. The significance of autoignition temperature data obtained using various ignition criteria is discussed to show the usefulness of such data in evaluating fire and explosion hazards. In addition, data are presented on the extent of oxidation that occurs prior to autoignition of this fuel in air at various temperatures.

Jan 1, 1965

By E. J. Schneider

In view of the current interest in the constituents of low-temperature tar, the Synthesis of three known xylenols and their hydroxyacetic acid derivatives has been undertaken by the U. S. Bureau of Mines. One of these xylenols, the 1,3,2 derivative first reported by Steinkopf and Höpner,4 has been described by Brown and Branting.5 The other two derivatives, the 1,3,5 first reported by Schütz6 and the 1,2,3 reported by Steinkopf and Höpner, have now been studied in greater detail. In the present work the synthesis of 1,2,3-xylenol and 1,3,5-xylenol was repeated, with some improvements in the former. The hydroxyacetic acid derivatives were also prepared, and it was found that while the melting point of the 1,2,3 derivative agreed with that of Steinkopf and Höpner. that of the 1,3,5 derivative was found to be 111° instead of 85 to 86° as reported by Schütz, by Steinkopf, and later by Bruckner. The discrepancy between the melting-point figures is doubtless due to differences in the purity of the xylenols used in the synthesis of the acids. Schütz obtained his 1,3,5 acid by recrystallizing an impure sample obtained from a mixture of xylenols. The difficulty of obtaining a pure acid by starting with a mixture is demonstrated by Bruckner, who despite painstaking efforts was unable to obtain the pure 162.5° melting 1,2,4 isomer from a mixture that persistently melted at 138° C. Steinkopf did not repeat Schütz's work but merely used the latter's figures in compiling a table. Bruckner, on the other hand. apparently also made the acid (by an improved method), and it is difficult to explain his checking Schütz's figure, unless it is that he, too used a symmetrical xylenol obtained from a tar and not prepared synthetically, as was the one reported in this paper.

Jan 1, 1929

By E. P. Youngman

Except possibly by individual natives and Liberians (small specters), is now being carried on in Liberia, according to a late report. definite information is obtainable with respect to the mineral resources of e country, except that iron ores are said to be abundant. Tin, copper, zinc, site, corundum, lead, bitumen or li nite, and diamonds have all been re- parte, but no commercial Geposits are known to have, been found. Gold has been duce, but not in significant amounts, as may be inferred from the customs - rt for Liberia recording the exportation of gold to the value of $4.80 Germany from the port of Cape Mount in 1925. It is not uncommon for atives to come into towns with African gold and valuable minerals, but they e reluctant to sive information concerning then. Some years ago the Liberian Government was seeing a loan in return for oil concessions, but apparently no drilling bea boon don

Jun 1, 1932

By Lloyd A. Morley, Alan M. Christman

Introduction A wealth of information exists which deals with electrical grounding, both from a general viewpoint and from a specifically mine-oriented approach. Many parameters must be investigated in order to thoroughly cover all of the variables which govern the performance of electrical grounding systems. The emphasis of this work on open-pit practices re- presents a new development in the field of grounding research, and an exhaustive review of the relevant historical documentation is especially desirable. Grounding System Purposes What purposes are served by a grounding system? The answer is four-fold and may be summarized as follows. First, it must limit potential gradients between conducting materials in a given area (56). When a phase conductor comes into contact with a machine frame, current flows through the equipment, which tends to become elevated above ground by an amount equal to the voltage on the conductor. If a man were to touch the machine while he was simultaneously connected to ground in some manner, his body would also tend to become elevated in potential, possibly to a lethal extent. Thus, the grounding system should provide a low- resistance path for the fault current to return to the source. The maxi- mum potential to which a man could be exposed when touching a machine frame is equal to the voltage drop along the ground conductors inside the power cable, as shown in Figure 1 (54). The ground conductors, therefore, (page # 96 is missing from the original document)

Jan 1, 1976

By R. M. Gammell, S. H. Lorain

The Anderson prospect is one of a number of properties investigated by the Bureau of Mines during the course of preliminary studies of the lead-zinc districts of northern Stevens County, Washington. examined by W. R. Green, an engineer of the Bureau of Mines, in June 1944. This examination was supplemented in late 1944 and the spring of 1945 by pre- The property was first liminary angle-dozer trenching and core-drilling. A second examination of the property was made by the junior author in November 1945. The data obtained in the course of these studies is presented in the following report.

Mar 1, 1947

By W. H. Kerns

The Critchfield manganese deposit, Huntingdon County, Pa., was investigated by the Bureau of Mines in October 1942. Iron ore was mined from an open cut just southeast of the manganese deposit about 80 years ago. The Critchfield Sand & Feldspar Co. was operating (1942) a clay-mining and beneficiation plant northeast of the manganese deposit. The Bureau completed six rotary bucket-drill holes and three hand-auger holes, aggregating 370 feet on the deposit. This report describes the work performed and presents the results obtained.

Jan 1, 1948

By B. K. Shibler, I. S. Solet, H. W. St. Clair

"This study was undertaken to provide a more adequate knowledge of the chemistry of the sulfide volatilization process for recovery of tin from low-grade Bolivian ores. The investigation was partly supported by the Department of State under its program for scientific cooperation with South American republics.The results of this investigation demonstrate the conditions under which cassiterite (Sn02) may be converted to stannous sulfide by reaction with pyrite or sulfur vapor. Quantitative data are given on the rate of sulfidization and on the vapor pressure of stannous sulfide.INTRODUCTIONAlthough the United States is the world's largest consumer of tin, virtually no tin ores occur within our national borders. Most of the world's tin supply comes from alluvial deposits in the Far East and in Africa, The major sources of tin ores are Malaya, Indochina, Bolivia, Belgian Congo, Nigeria, Thailand, Burma, China, and the United Kingdom. Bolivia is the only important source of tin in the western hemisphere. It was the chief source of tin f or the United States during World War II. The Government-owned tin smelter at Texas City, Tex., was built primarily for smelting Bolivian ores and depends largely on Bolivian ores for its operation. Bolivia is the only major tin-producing country in which the tin ores occur as vein or lode deposits requiring underground mining. Most of the tin from the Far East and Africa is mined by dredges from alluvial or placer depos its. It is recovered as a high-grade concentrate of cassiterite relatively free from impurities. The tin minerals in the lode deposits are more intimately associated with other minerals and more difficult to separate into a clean concentrate. Furthermore, a large part of the tin in the original ore is lost during concentration. The ores as mined contain only a few percent of tin, so they must be milled to separate the gangue minerals and produce a concentrate containing 30 to 40 percent tin before they are shipped to the smelter. The losses of tin that occur during milling vary from 18 to 65 percent. The average recovery of tin from Bolivian ores is probably 50 to 60 percent."

Dec 1, 1954

By Michael J. Griffin

Science involves the study of the nature and behaviour of natural things and the knowledge we obtain about them. Scientific endeavour leads to the unfolding of new knowledge and adjustments to our understanding and our behavior. To indicate that we ‘know’ something may merely mean we do not feel able to, or that we do not wish to, disagree with others who claim to know; or it may mean we have either heard about it, or studied it, or understand part of it, or accept that it is true, or have seen evidence to be convinced of its veracity. What do we ‘know’ about the health effects of vibration? There are many unknowns in the field of human responses to vibration. Not all would agree on what is known and what is unknown. This paper seeks to summarize what we know that we know, what it is sometimes claimed that we know, and what we know that we do not know about the relation between exposures to vibration and our health. It also speculates on what we do not know that we do not know. Hand-transmitted vibration What we know we know We know that exposures to hand-transmitted vibration result in various disorders of the hand, including abnormal vascular and neurological function. Not all frequencies, or magnitudes, or durations, of hand-transmitted vibration cause the same effects. What we may claim to know To enable exposures to be reported and compared, they are ‘measured’ and ‘evaluated’ using defined (e.g. standardised) procedures. This involves identifying what is to be measured and specifying how it is expressed by one (or a few) numbers. Summarising a vibration exposure in a single value involves assuming the relative importance of components within the vibration (e.g. different magnitudes, frequencies, directions, and durations), so standards define ‘weightings’ for these variables. The importance of the weighted values may also be suggested, allowing ‘assessments’ according to a criterion (e.g. the probability of a specific severity of a specific disease). Standards for the measurement and evaluation of hand-transmitted vibration define a frequency weighting and time dependencies that allow the severity of vibration exposures to be assessed and the probability of finger blanching to be predicted 1. What we do not know We do not know that the frequency weighting in current standards reflects the relative importance of different frequencies and axes of vibration in producing any specific disorder. We do not know whether the energy-based daily time-dependency inherent in A(8) reflects the relative importance of vibration magnitude and daily exposure duration. Consequently, the relation between A(8) and the years of exposure to develop finger blanching, as in an appendix to ISO 5349-1 (2001), is not well-founded. We do not know, or at least there is no consensus on, the full extent of the disorders caused by hand-transmitted vibration (e.g. vascular, neurological, muscular, articular, central), or the pathogenesis of any specific disorder caused by hand-transmitted vibration, or the roles of other factors (e.g. ergonomic factors, environmental factors, or individual factors). We know that acute

Jan 6, 2006

By A. C. Fieldner

In preparing this paper, an attempt was made to obtain results of plant-scale carbonization tests on washed and unwashed coal from the same mine. A letter. in which the following questions were asked was sent to some 50 coke-oven superintendents and others who might be interested; "What is the influence of washing coal on: (1) The chemical and physical properties of coke, as for example, the size the amount of breeze, the fracture, strength, cell-structure, etc. (2) The quantity and quality of gas and by-products. (3) The capacity of the ovens. (4) The composition of the coal. "Your general opinion, as well as any specific data or results of tests, on this important subject will be arc greatly appreciated."

Jan 1, 1930

By H. C. Ko

Calorimetric determinations of low-temperature heat capacities and the standard enthalpy of formation were made by the Bureau of Mines for aluminum sulfide, A12S3. The standard entropy (S°), enthalpy of formation (?Hf°), and calculated Gibbs energy of formation (?Gf°) at 298.15 K are 27.93±0.05 call deg-mole, -155.6±0.9 kcal/mole, and -153.0±1.0 kcal/mole, respectively.

Jan 1, 1976