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By S. L. May

Investigations by the Federal Bureau of Mines indicate that hafnium and zirconium compounds of acceptable purity can be extracted from Nigerian zircon concentrates. Chlorination and caustic soda fusion techniques were used to extract 85 to 95 percent of the valuable metals from the concentrate. The extracted hafnium and zirconium compounds were purified by recrystallization of the oxychlorides or by formation of complex salts during chlorination. The zirconium-hafnium product of the recrystallization method contained 15 parts per million of uranium, and the product of the salt-complex method contained less than 10 parts per million of uranium. The hafnium was separated from zirconium by solvent extraction methods. A zirconium product containing 0.3 percent hafnium and a hafnium product containing 4 percent zirconium were obtained. At the request of the Atomic Energy Commission (AEC), work was started to develop techniques for processing Nigerian zircon concentrates in commercial installations presently engaged in producing zirconium and hafnium metals from ores. The Nigerian zircon has a high hafnium content, but the presence of uranium and thorium is a problem not normally encountered in processing zircon concentrates.

Jan 1, 1961

By N. Kumar Kittusamy

A field study was conducted to evaluate seat designs on shuttle cars. Eight operators participated in evaluating seat designs on the basis of perceived levels of vehicle jarring/jolting and discomfort. Researchers also measured the levels of vehicle jarring/jolting. Four basic seat designs were compared on low and mid-coal seam shuttle cars during production operations at two underground coal mines. Two seats were currently used on the shuttle cars and another two were NIOSH designs. Objective data were collected using accelerometers with pre-amplifiers and filters connected to a data recorder; whereas subjective data were gathered with a visual analog scale (VAS) and a questionnaire. Results from measured levels of jarring/jolting showed that the NIOSH Seat L2A smoothed out bumps better than any other seats. Using the VAS, mid-seam and low-seam shuttle car operators rated the levels of jarring/jolting and discomfort lower with the NIOSH seat than the other seats. Questionnaire responses indicated that operators rated NIOSH seat designs as more comfortable. This research will provide the industry with better seat designs for isolating jarring/jolting in vehicles. Furthermore, researchers plan to improve the NIOSH seats using information gathered in this study.

Jan 1, 2003

By Elaine T. Cullen, Thomas W. Camm

The mentor/learner model is a time-honored approach to teaching, including within the mining industry. Miners know when they see excellence and have a deep respect for experts in their field. By using expert miners as mentors to other, less-experienced miners, training programs can be developed that will have a legitimacy and credibility that resonates with those being trained. Building upon concepts in current theories of adult education, this paper highlights the unique advantages of using mentoring as a teaching method that can make the educational experience both interesting and effective. Current NIOSH safety training materials use these concepts to deliver effective adult learning experiences for workers in the mining industry.

Jan 1, 2002

By Alla D. Mah

No experimental heat-of-formation value has been reported in the literature for cerium sesquioxide. The heat of formation of bismuth sesquioxide has not been determined in recent years, and the older value was subject to large uncertainty. Accordingly, the heats of combustion of cerium sesquioxide and bismuth metal were measured by the Federal Bureau of Mines. The heats of formation were: ?H°298.15 = -427.01 ± 0.70 kcal. /mole for cerium sesquioxide and ?H°298.15 = -137.16 ± 0.30 kcal./mole for bismuth sesquioxide. The free energy of formation was estimated for cerium sesquioxide and accurately calculated for bismuth sesquioxide. The data were compared with values in the literature.

Jan 1, 1961

By W. W. Odell

The results of the 1921 cooperative experiments conducted by the U. S. Bureau of Mines and the University of North Dakota at the University mining substation plent at Hebron , North Dakota , pointed clearly to certain definite dep ficiencies in the schemes hitherto developed for benefiting and utilizing lignite . First The apparatus used in the carbonizing process or used to produce carbonized lignite suitable for briquetting is too costly , that is , the cost per ton day of residue made is too high . Second - The depreciation of the carbonizing appara tus is too high . Third The carbonizing apparatus can not be operated intermittently without seriously damaging it and impairing its efficiency of performance . Fourth Too little attention has been given to the possibility of using at least a certain percentage of the carbonized lignite directly in suitable stoves and furnaces without briquetting or other treatment . Accordingly , consideration was given to the design of an oven that could be built at a mine without the importation of highly skilled and specially trained construction men , erected at a low first cost , readily kept in a state of repair , operated at a rela tively high capacity and put into operation or shut down at will without seriously damaging the brickwork . The need of such an oven was appreciated also by the University of North Dakota and a cooperative agreement was made to build and operate such an oven during the summer of 1921.

Feb 1, 1923

By Donald O. Capstick

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Jan 1, 1983

By Stephen P. Signer, John L. Lewis

This paper presents the results of a case study conducted in a two-entry gateroad in a coal mine where excessive roof deformation and bolt loading resulted in failure of many roof supports. The instruments consisted of 16 fully grouted, strain-gaged resin bolts, load cells on both full and partially grouted cable bolts, and vertical deflection multipoint extensometers. These instruments were installed on-cycle to measure loading on bolts in an existing support pattern and to determine if cable bolts could be used to improve roof stability. Results showed significant amounts of movement within the bolted zone. In some cases, these movements were enough to load the supports past their ultimate strength. Geology appeared to be a significant factor in localized roof degradation; that is, a very weak rock layer in the immediate roof overlain by a very strong rock layer contributed to the development of shear planes. Only one instrumented bolt had a maximum strain of less than 2,000 microstrain, which was the yield point of the steel. The average maximum strain on all bolts was 20,000 microstrain. However, electrical continuity to many gages was lost and a pattern was noted that would indicate possible bolt failure. Wire mesh and concrete cans installed as secondary support performed very effectively.

By Thomas M. Barczak

Roof support technology for longwall tailgates has changed dramatically during the past decade. Filling tailgates with conventional wood cribs is becoming the exception rather than the rule. Modern engineered timber support systems and a host of other alternative support products provide far greater capacity as well as stiffer response, thereby allowing the supports to resist roof movement with much less displacement than the soft wood cribbing used in the past. For these reasons, these products can provide superior roof control. In addition, the material handling requirements for support installation have now become a major consideration in the support design and selection process. Products such as conventional wood cribbing that require piece-meal construction of bulky, heavy components have diminished, while prop-type supports and products that can be installed with machinery and pumpable support technologies have grown in use resulting in fewer injuries to mine workers. Now, the opportunity exists to provide the safest, most cost effective support system, through engineering design rather than by trial and error and to optimize the use of the support system chosen. Yet this is rarely done. The key to accomplishing this task is to understand the interaction of the support system with the ground conditions at the installation site. A major focus of the paper is to conceptualize the support and interaction through the use of a ground reaction curve which relates the support resistance to the convergence of the longwall tailgate. The goal of any roof support design is to control the ground deformations and maintain the structural integrity of damaged or broken ground to the extent possible to provide a stable mine opening. In general, deformations will be a function of the stress environment and inherent strength of the surrounding rock mass. However, if the deformations are intimately linked to the stress changes such that the deformation can be controlled by the load resistance or reinforcement provided by a roof support system, then the loading behavior can be described as load-controlled. Conversely, if the deformation occurs irrespective of the installed support (assuming practical limitations), then the loading behavior is described as displacement-controlled. In this case, the deformation can be considered irresistible from a practical standpoint. In this context, the nature of the loading has significant consequences on the support design requirements. Finally, examples using the NIOSH Support Technology Optimization Program (STOP) to develop design criteria using ground reaction data from underground studies and ways to include uncontrolled convergence as part of the design criteria for standing roof supports will also be discussed.

By E. J. Murphy

"INTRODUCTION This investigation is a continuation of previous work 3/4/5/ on the gaseous products of permissible explosives with and without sheaths. The range of oxygen balance of the explosives has been considerably increased. As has been shown previously, certain approximate relations exist between the volumes of gaseous products and the oxygen balance. Further systematization of the data is not feasible, since the method of theoretioal calculatln of the gaseous product is not yet satisfactorily developed. In a previously described method, 6/ it has been assumed that the explosion occurs at constant volume and that thermodynamic equilibrium is established. Apart from the presumably less important uncertainty of some of the thermodynamic data, it is not known how the confinement of the shots in the Bichel gage or the Crawshaw-Jones gage should be treated, or whether thermodynamic equilibrium is fully attained; nor can the extent to which the equilibrium composition changes during the subsequent period of expansion and cooling be judged with any reliability. Therefore, no calculations have been attempted. However, in anticipation of possible future theoretical interest and as an aid in answering practical problems, the new data are presented in the same minute detail as was done previously."

Mar 1, 1948

By R. H. Nafziger

The Bureau of Mines evaluated 18 domestic titaniferous materials with widely varying compositions, mineralogy, and physical properties in electric-arc furnaces, Techniques were devised to recover both the titanium and iron values contained in these materials so that the reliance of the United States on foreign sources of higher grade ilmenites and rutile might be decreased. Most of the tested titaniferous materials responded well to lower grade or byproduct reductants, such as bituminous coals, charcoal, and coke breeze. Sufficient slag fluidity was realized by maintaining from 8 to 12 wt-pct iron in the slags; no contaminating fluidizers were required. Fluid slags containing up to 79, 70, and 54 wt-pct Ti02 were realized from east coast ilmenites, a rock ilmenite, and a titaniferous magnetite ore, respectively. A carbon-lined furnace shell is recommended for minimum slag contamination. Good results also were obtained during extended submerged-arc furnace tests.

Jan 1, 1980

By W. R. Hardwick

This information circular describes open-pit mining methods and practices of the Bagdad Copper Corp., Yavapai County, Ariz. It is one of a series being prepared by the Federal Bureau of Mines on mining methods, practices, and costs in various mining districts of the United States. A brief history of the Eureka district and of early developments at the [gdad] mine is given, and the are deposit is described with particular emphasis on those characteristics (physical, economic, or engineering) that affected the choice of mining methods. Prospecting, exploration, and sampling and estimating the tonnage and grade are outlined. Development of the open-pit mine is shown. Mining methods, including breaking ground, primary drilling and blasting, secondary drilling and blasting, loading, transportation, engineering, and operating control, are described. A brief summary of mining equipment is given. Percentage of extraction, production rate, mine drainage and water supply, wage, contract, and bonus systems, safety and fire prevention, and the processing plant also are described. The last section gives a breakdown of such costs as are available for publication.

Jan 1, 1959

By R. D. Leitch

"REASONS FOR AND PURPOSE OF WORKIn 1924 the United States Public Health Service was requested to undertake a special study of stream pollution. At that time the proposal that the United States Bureau of Mines take up the study was made by the Public Health Service because in point of training and experience the personnel of the latter was considered not to be as well, suited to this type of investigation as was that of the Bureau of Mines. H. Foster Bain, then Director of this bureau, promised to undertake the work, and, accordingly, field investigations were begun in the spring of 1925. The problems of mine-drainage wastes and of gas-house and coke-oven waste were investigated in the laboratory, and a method of treatment by sodium hydrate and benzol was found to be promising. The idea was obtained by A. C. Fieldner, chief engineer of the Bureau of Mines experiment stations, while in Germany in 1924, where he was shown a practical application of the process, but no information was obtained as to definite chemical or mechanical processes. Because of the then pending American patent application by the German firm, we made no attempt to develop our findings further. Shortly after, a similar method of treatment was developed in the United States, and since that time we have devoted our attention entirely to mine drainage. This paper is a presentation of some general facts and information gathered during the past five years on coal-mine drainage.SCOPE OF WORKAt the time our work was begun there was such a diversity of opinion on the whole subject and apparently so little was accurately known, that it was decided to undertake a basic study from which (1) certain definite information might be evident, and (2) what might be considered side issues of the original investigation would be suggested for subsequent study.A stream in a district thought to be representative of those in low to average sulphur bituminous coal fields and another in a high sulpbur district were selected for study, A fair (weber of factors entered into the tentative selection of these streams, the chief ones being their accessibility and freedom from other industrial or domestic pollution, besides, of course, the presence of mine drainage in these streams."

Apr 1, 1931

Objective: To help prevent squeezes, collapses, and other pillar failures through better pillar design, thereby enhancing safety for underground mine workers.

Jul 1, 1997

By Paul H. Mutschler

The Bureau of Mines sponsored a study of the impact of changing technology on the demand for metallurgical coal and coke to 1985. Individual technologies were analyzed to determine what effect each had on the demand for and the consequent consumption of metallurgical coal and coke in the steel industry. The domestic steel industry demand for metallurgical coal and coke for the production of hot metal will probably increase through 1985. Formcoke if implemented on a worldwide basis could begin to supplant the U.S. export market for metallurgical coal. The major technologies that have contributed to the decline in demand for metallurgical coke per ton of hot metal are (1) the increased usage coupled with higher iron content of agglomerates, (2) modification of blast furnace practices such as high top pressures and blast temperatures, and (3) increases in the injection of supplemental fuels. The projected demand for metallurgical coal and coke under current technology for 1985 are 109.4 and 76.0 million tons, respectively. With future technology implemented, the demand for metallurgical coal and coke will be 82.0 and 56.9 million tons, respectively. The projected domestic demand for metallurgical coke could further decrease by as much as 15 to 20 million tons by 1985 if formcoking proves technologically and economically feasible.

Jan 1, 1975

By H. B. Humphrey

The solvents used most widely in industry may be divided into groups according to their chemical and toxicological properties. These groups, with representative members, follow: Petroleum distillates (aliphatic hydrocarbons) Examples: Gasoline, benzine, Stoddard's specification solvents. Alcohols, esters, ketones, ethers, and ether alcohols Examples: Denatured alcohol (ethyl alcohol to which various denaturants may be added), methanol (methyl alcohol), ethyl acetate, amyl acetate (banana oil), acetone.

Jan 1, 1956

By Ted C. Briggs

A removable-jacket distortion apparatus was constructed and used to measure distortion coefficients for two high-pressure vessels. The measured distortion coefficients were used to compute distortion coefficients for volumes VI and (V1+V2) of a 1,000-atmosphere Burnett compressibility apparatus for the temperature range 0° to 75° C. Young?s modulus for Armco 17-4 PH stainless steel, heat treated to condition H1150-M, was computed from experimentally determined distortion coefficients. A 10-to 14-percent correction to the values obtained for Young's modulus may be required because pressure vessel end effects were neglected. The distortion coefficients of the compressibility apparatus are believed to be accurate to about 1 percent.

Jan 1, 1970

The Production Profile Program is written for use on a Digital Model PDP 11/70 computer using a Fortran IV level G language. It may be run on any system which uses G level or an upward compatible version of Fortran IV language. Please note, however, that the Model PDP 11/70 for which the program was written is programed to read DEC026 type keypunching. If the user's computer is programed for another type of keypunching it may be necessary to re-keypunch the Production Profile Program. The Production Profile Program uses a fourteen card input. The data must be keypunched according to the layout described in detail in the multiple card layout forms (following). The output from this program must be printed on wide paper, as a full 120 columns are used. The samples of output at the back of this appendix have been reduced for inclusion in this report.

Jan 1, 1977

By S. J. Broderick

[The authors gratefully acknowledge the assistance of O. C. Ralston, chief engineer, Nonmetals Division, Bureau of Mines, Who suggested the problem and Gave valuable aid during the course of the work. Thanks axe due also to Will H. Coghill, supervising engineer of the Southern Experiment Station, Bureau of Mines. INTRODUCTION One phase of the general program for utilization of coal-mine waste led to the possibility of making a water softener from the material, as the waste matter contained both coal and clay and. it is known that both these substances can be so activated as to exhibit distinct base-exchange properties. The carbonaceous]

Jan 1, 1941

By S. J. Broderick

[One phase of the general program for utilization of coal-mine waste led to the possibility of making a water softener from the material, as the waste matter contained both coal and clay and it is known that both these substances can be so activated as to exhibit distinct base-exchange properties. The carbonaceous]

Jan 1, 1941

By G. David Baskin

Changes in the 1978 quantity and value of the sales of various natural abrasives, compared with the data for 1977, were of a mixed nature. Output of tripoli-type materials and garnet increased in both tonnage and value. Emery production also increased. But special silica stone product sales decreased in both tonnage and value, and the reported quantity and value of sales of manufactured abrasive material also decreased for 1978. In 1979 output of tripoli-type materials and special silica stone products decreased in both tonnage and value when compared with the previous year. The tonnage and value of sales of garnet and manufactured abrasives increased when compared to 1978 data.

Jan 1, 1980