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By A. W. Deurbrouck

The Bureau of Mines analyzed 13 samples collected from three Randolph County coalbeds. The Peerless and Sewell bed samples were generally of metallurgical quality as received from the mines or could be easily upgraded. How-ever, the Lower Kittanning coa1bed samples proved to be quite inimical to upgrading to metallurgical quality.

Jan 1, 1966

By D. Randolph Berry

Volume II contains appendices which explain and document the recommendations of Volume I. The following topics are covered: Appendix A Discussion of Recommended Guidelines Appendix B Worldwide Use of Oxygen Self-Rescuers Appendix C Hypothetical Use of Oxygen Self-Rescuers in Post-1972 Coal Mine Explosions and Fires Appendix D Vibration Testing of SCSRs Appendix E Testing of In-Service Chemical Oxygen SCSRs Appendix F Discussions with Representatives of Underground Coal Mining Appendix G Recommendations for SCSR Storage Containers Appendix H Example SCSR Storage Plans Appendix I Testing of In-Service Compressed Oxygen SCSRs Appendix J 30 CFR 75.1714, 30 Regulations Pertaining to Self-Rescuers

Jan 1, 1981

By M. M. Fine

"Button" type ore from the Cason mine, Batesville, Ark., can be up-graded to plus-40-percent manganese by mineral-dressing procedures. A simple process including gravity concentration and. magnetic separation yielded more than 50-percent recovery of concentrates containing 38.1 to 40.6 percent manganese. These values in turn could be raised to 41.4 and 42.8 percent, respectively, upon sintering to conform to size specifications. The Bureau of Mines in the past has surveyed and tested many manganese ores and prospects in an endeavor to alleviate the shortage of manganese. The present period of emergency again emphasizes the strategic position of the metal, and manganese investigative work is being stressed to find new ore bodies and to apply newer beneficiation techniques to the known deposits.

Jan 1, 1953

By Lloyd Williams, H. K. Gibbs, William L. Crentz, J. W. Miller

"Reserves This investigation shows that the Poplar Creek is the most important bed in Scott County from a production standpoint. Although the Poplar Creek bed contains the largest reserve, the Big Mary has a larger recoverable reserve. Estimates of reserves also have been made for the Pewee, Red Ash, Windrock, Upper Pioneer, Jellico, and White Oak beds.Known measured and indicated reserves of coal, based on a minimum bed thickness of 14 inches and on 1,800 short tons per acre-foot of coal in place, are estimated to be 143 million tons as of January 1, 1954. Of this total, 74 million tons is in beds 28 inches and more thick. Areas in each bed were omitted from the estimate because available data relative to the bed characteristics are too meager for making an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves.Recoverable reserves of coal are estimated in beds 28 inches and more thick. This thickness is about the minimum now being mined by hand loading onto conveyors in the Appalachian region. The weighted average recovery for all beds in Scott County, as determined by this investigation, is 52.4 percent. This percentage is based on the total thickness of coal in the bed (less partings three-eighths inch or more thick) rather than on the thickness of the coal mined. Based on the weighted average percentage of recovery for all beds in Scott County, the recoverable reserves of coal are estimated to be 39 million tons as of January 1, 1954.Coal Analyses Chemical analyses of coal samples taken for this study show that the coal in Scott County is of high-volatile a bituminous rank except the Upper Pioneer bed, which is shown to be high-volatile B bituminous. The Pewee bed shows typical low-sulfur characteristics. The high ash and sulfur in the Big Mary are characteristic of that bed. The Poplar Creek is moderately low in ash and sulfur in areas where there is no parting in the bed."

Jun 1, 1956

By H. R. Babitzke

The purpose of this investigation was to develop an alloy of columbium for use at high temperatures and for nuclear applications. The properties of possible alloys were determined, and the more promising ones were selected for further improvement. Criteria for selection were machinability, hardness, workability, tensile strength, and oxidation resistance. Thirteen 100-gram ingots, ranging from 100 percent columbium to 100 percent vanadium, were prepared and subjected to various tests. Also included for comparison were zirconium and the zirconium alloy, zircaloy-2. Test results showed that a columbium alloy, containing 10 atomic percent vanadium merits further development. Besides being workable at room temperature, the columbium-10 atomic percent vanadium alloy has oxidation resistance superior to the other alloys of the series and is also superior to zirconium or zircaloy-2. The latter two materials have comparable neutron-absorption cross sections. The strength and hardness values of the alloys tested were found to increase with increasing vanadium content, reaching a maximum at 50 atomic percent vanadium and decreasing with further increase in vanadium. This behavior is typical of binary alloys wherein each element will retain any proportion of the other in solid solution. INTRODUCTION There is an increasing need for alloys for service at high temperatures. Since current world reserves of columbium metal approximate 1,500,000 tons (1),4 this metal is now readily available. Columbium can ties; be considered a practical base material for high-temperature alloys required in nuclear reactors and in aircraft and space vehicles. General requirements chosen are: (1) Workability, (2) satisfactory mechanical properties at temperatures approaching 1,000° C., and (3) resistance to oxidation at such temperatures.

Jan 1, 1962

By S. M. Moore

Technological advances in underground coal mining have reduced fatalities but may not have reduced worker exposure to cumulative injury risk factors. The objective of this study was to evaluate the prevalence of cumulative injuries before and after the implementation of technological advances in underground coal mining and to make a general cost estimate for these injuries. A previously published algorithm was utilized to identify cumulative injuries within the Mine Safety Health Administration (MSHA) database for two data sets: 1983-1984 and 2003-2004. For both, the following were determined: the number and percentage of cumulative injuries, the average days lost, the average age at the time of injury, the average years of experience and the general cost estimate by body part. The percentage of cumulative injuries remained largely unchanged (37 percent in the 1983-1984 period and 33 percent in the 2003-2004 period). The average number of lost days due to cumulative injuries increased (36±55 days and 62±82 days, respectively), which may have been due to the increased worker age (seven years older in the 2003-2004 period), increased length of employment (seven years longer in the 2003-2004 period) or other factors such as changes in medical practices. Cumulative injuries to the back decreased by 10 percent, while cumulative injuries to the knee increased by 8 percent. The reduction in back injuries may be due to the implementation of assist devices, while the increase in knee injuries may be related to kneeling/crawling in low-seam mines. Cumulative injuries were found to remain a major financial burden on the industry. Recently, National Institute for Occupational Safety and Health (NIOSH) developed tools to assist mining companies with incorporating an ergonomics process into their existing health and safety programs. The participating companies have reported tremendous success. Therefore, it is recommended that ergonomics processes be implemented as a means to systematically identify and address the root causes to cumulative injuries and ultimately reduce costs.

Jan 1, 2008

By F. E. Joyce

The Bureau of Mines studied copper-nickel minerals (mainly sulfides) of the Duluth Gabbro Complex in north-eastern Minnesota to determine their response to selective high-temperature sulfatization techniques. The gabbro, containing 0.44 percent copper and 0.13 percent nickel, was ground to minus 325 mesh and sulfatized in a heated, rotating, stainless steel bench-scale retort. Tests demonstrated that over 95 percent of the copper and 80 percent of the nickel can be converted to water-soluble sulfates, depending upon the roasting conditions employed. Yield equations were developed using regression analysis for predicting the extraction of copper and nickel between the temperature limits of 520° to 670° C, the roasting time limits of 3 to 7 hours, and S02 limits of 10 to 40 percent in S02-air mixtures.

Jan 1, 1971

By R. H. Nielsen

A new, cheaper precipitation scheme has been developed to produce purified zirconium oxide, Technical-grade sulfuric acid is used to precipitate a basic zirconium sulfate from a hot dilute hydrochloric acid solution. With close control of temperature, pH, and zirconium - sulfate ratio, excellent purification and complete zirconium recovery can be attained. The process has been successfully applied for 3 months and has proved to be a more satisfactory procedure than the ammonium phthalate process used previously. INTRODUCTION The Northwest Electrodevelopment Laboratory of the Federal Bureau of Mines has developed and improved the Kroll process for the production of pure ductile zirconium and hafnium. metal. Since 1946 over 1 million pounds of zirconium sponge metal has been produced, mostly high-purity material for the Atomic Energy Commission

Jan 1, 1956

By S. J. Pearce

"INTRODUCTION AND SUMMARYComplaints have been made regarding dust respirators that may be used in coal-mining operations. Some of these complaints may be due to improper use of the respirator, inadequate knowledge of its purpose and mode of functioning, poor choice, poor fitting, or inadequate maintenance. It is hoped that this circular will answer these complaints by discussing the various factors relating to the proper use of dust respirators in general and in coal mines in particular.It is pointed out that dust respirators are not to be used as a substitute for dust-control measures. The construction, functioning, choice, fitting, and maintenance of dust respirators are discussed.FIELD OF USEThe function of the dust respirator is to prevent the wearer from inhaling harmful quantities of dust by removing dust from the air he inhales.A dust respirator is not to be used as a permanent substitute for dust-control measures. It is to be used as a temporary substitute until dust-control measures can be instituted or as a protective means where dust-control measures are impracticable, as in applying rock dust in bituminous-coal mines.The following sections of the ""Federal Mine Safety Code for Bituminous-Coal and Lignite Mines in the United States"" 2/ emphasize the fact that every effort should be made to keep the amount of dust in the air of the working places as small as possible:"

Mar 1, 1950

By E. S. Leaver

Experiments dealing with the dissolution of silver by cyanide from various silver minerals-were reported, several years ago.4/ This work showed that the silver in some silver minerals is completely and readily soluble in cyanide solution, whereas other silver minerals must be given special treatment before or during cyanidation to obtain much dissolution of the silver by cyanide. Flotation as a method for treating silver ores has not been studied much, except in the case of base-metal ores carrying silver, Particularly lead-silver ores. However, many mills now are concentrating gold ores by flotation, and when such ores also contain silver the recovery of the silver by flotation is of considerable importance. Moreover, many mines contain ore in which silver is the principal valuable constituent. Some of these ores are amenable to cyanidation, but the cost of a cyanide plant may be prohibitive because of limited ore bodies or other factors. In such instances the successful application of flotation would mean that the property could be operated.

Jan 1, 1939

By E. S. Leaver

Experiments dealing with the dissolution of silver by cyanide from various silver minerals were reported several yews ago.4/ This work showed that the silver in some silver minerals is completely and readily soluble in cyanide solution, whereas other silver minerals must be given special treatment before or during cyanidation to obtain much dissolution of the silver by cyanide. Flotation as a method for treating silver ores has not been studied much, except in the case of base-metal ores carrying silver, particularly lead-silver ores. However, many mills now are concentrating gold ores by flotation, and when such ores also contain silver the recovery of the silver by flotation is of considerable importance. Moreover, many mines contain ore in which silver is the principal valuable constituent. Some of these ores are amenable to cyanidation, but the cost of a cyanide plant may be prohibitive because of limited ore bodies or other factors. In such instances the successful application of flotation would mean that the property could be operated.

Jan 1, 1939

By R. O. Pynnonen

Tunnel-driving is recognized as a hazardous occupation; adequate support of roof and sides for preventing accidents from falling material is usually one of the most important safety problems. Where extraordinary conditions of sand and water are found, this problem becomes even more difficult. Tunneling at the Tioga No.2 mine was stopped when a 22-foot bed of water-saturated, fine gray sand was encountered. The tunnel, designed to house an ore-conveyor belt, was being driven from both ends. Driving was extremely difficult at both the upper and lower faces when the sand horizon was reached. A distance of 178 feet remained between the faces. Heavy pressures deformed the steel-supporting rings at the upper face, and there was an inrush of mud and sand at the lower face.

Jan 1, 1958

By C. W. Whitten

Iron ore deposits in south-central Missouri have emerged as a possible resource for the rare-earth elements. The Pea Ridge Iron Mine is one such deposit. Rare-earth minerals at the Pea Ridge Iron Mine are contained in breccia pipes consisting primarily of silicon oxides and feldspars. These pipes extend up through the magnetite ore body and appear to be alterations and replacement of earlier hematite. The mineralogy of these pipes is very complex and varied, which could complicate the concentration and extraction of the rare-earth minerals. This U.S. Bureau of Mines !eport represents a study by characterization of the mineral phases to assess the amenability and development of concentration and extraction techniques. Previous characterization of rare-earth minerals has been mainly by transmitted light microscopy. This method along with reflected light microscopy, scanning electron microscopy, and X-ray diffraction was used to identify and characterize the rare-earth and associated minerals. The minerals identified were the major ore minerals, magnetite and hematite; the rare-earth phosphates, monazite and xenotime; the rare-earth silicate, allanite; the minor associated minerals, cassiterite, pyrite, and apatite; and the gangue minerals, feldspar, quartz, and actinolite.

Jan 1, 1990

By A. F. Baker

Tests were conducted in commercial foundries to determine the suitability of calcined anthracite as a cupola fuel. The calcined anthracite performed satisfactorily at two of the three foundries where iron-melting tests were conducted. Performance at the third installation was unsatisfactory because metal temperatures deviated widely and, in general, were lower than is desirable for the type of castings being made.

Jan 1, 1963

By W. W. Adams

"The eighth National Safety Competition, that for 1932, conducted by the United States Bureau of Mines, was participated in by 322 mines and quarries operating in 34 States. Tables 2 to 6 show the relative standing of the various plants. Bronze trophies, known as the 'Sentinels of Safety,' which were provided by The Explosives Engineer magazine to be awarded annually by the Bureau of Mines, were awarded to five companies, each company having established the best accident-prevention record within one of the five classes into which all companies were divided, - namely, anthracite-mining companies, bituminous-coal-mining companies, metal-mining companies, operators of nonmetallic-mineral mines other than coal mines, and quarries or open-cut mines. The trophies are awarded for one year and are then transferred to the winners of the succeeding year's contest.The trophy for bituminous-coal mines, which has been in New Mexico for the past year, was won by a mine in West Virginia. The metal-mine trophy goes to New York State for the first time in the history of the contest. Previously it had been won by mines in Minnesota, Michigan, Kansas, and Oklahoma. The trophy for nonmetal mines remains for another year at Retsof, N. Y.; that for quarries and open-cut mines is transferred to a quarry in Michigan. The trophy for anthracite mines, of course, remains in Pennsylvania, as all anthracite mines in the contest are in that State.In determining the relative standing of the various companies enrolled in the competition, all mines and quarries were graded according to their accident-severity rates, - that is, according to the number of days of disability of employees on account of accidents in proportion to the number of man-hours of work done by all employees at the plant. Reports of accidents and of man-hours worked were furnished by the companies to the Bureau of Mines. These reports were carefully examined and classified to insure uniform weighting of accidents according to the number of days of disability to be charged and to insure uniformity of methods of calculating the accident-severity rates for the various mines and quarries. When the relative standing of all plants had been determined in this way, a summary of the records of the companies having the lowest accident-severity rates in their respective groups was sent to the members of a committee of award for examination in accordance with the rules governing the safety contest. The members of the committee of award were W. H. Cameron, managing director of the National Safety Council; William Green, president of the American Federation of Labor; James F. Callbreath, secretary of the American Mining Congress; T. T. Read, Vinton professor of mining engineering of Columbia University; C. B. Huntress, executive secretary of the National Coal Association; A. J. R. Curtis, assistant to the general manager of the Portland Cement Association; and A. T. Goldbeck, director of the bureau of engineering of the National Crushed Stone Association. When two or more mines within the same group operated without an accident during the year, the contest rules provided that the trophy for the group should be awarded to the plant whose record showed the largest number of man-hours worked."

Jul 1, 1933

By D. J. Bauer

The Bureau of Mines has conducted extensive studies on the recovery of alumina from kaolinitic clay by a HCI leaching-HCI sparging process. The current study reports a modification of the process, which involves a double-leaching system. The first leach of the calcined clay is made at as high a HCI acid strength as possible so that the dissolution of aluminum chloride hexahydrate (AlCI3*6H20) is suppressed, Most of the impurities, but very little aluminum, are soluble in the strong acid. After liquid-solid separation and washing, the solids are leached with recycled weak HCI, which dissolves the AICI3'6H2O. The pregnant liquor is separated from the gangue, and AICI3'6H2O is crystallized from solu-tion by injecting HCI gas. A proposed flowsheet is presented, and the effect of bleedstream size on AlC13'6H20 purity is discussed.

Jan 1, 1984

By L. Cheng

This report presents the results of a Bureau of Mines laboratory investigation of the effect of water sprays in reducing respirable dust that escaped the face area of a full-scale wooden model of a mine en-try containing a wooden model of a ripper-type continuous mining machine and exhaust brattice. Areas examined were (a) the general effectiveness of a low-pressure water spray system mounted on top of the mining machine boom, a high-pressure spray system mounted under the boom, and the combined top-and bottom-spray systems, and (b) the effect of these three spray systems on the capture of coal dust particles of different sizes. Dust was injected into a sump cavity at the face. Airborne respirable dust concentration was mea-sured behind the brattice with a personal sampler and cyclone, and particle size distribution was mea-sured with a cascade impactor. When used alone, the top-spray system captured about 55 pct of the respirable dust in the face area and the bottom-spray system captured 60 pct; the capture efficiency of each system is decreased when they are used simultaneously. From a mass-concentration viewpoint, each spray system preferentially captures larger dust particles.

Jan 1, 1988

By C. W. Owning

"The Bureau of Mines has repeatedly emphasized the necessity of completely ""rock-dusting all coal mines, except anthracite mines, in every part whether in damp or dry condition."" Every open accessible part of, the, mine without exception should be thoroughly rock-dusted, including parallel entries, air courses, trackless entries, crosscuts, and rooms to within at least 40 feet of every coal face. Very few mines have followed this recommendation and warning, with the result that there have been explosions not only in mines which have not used rock dust but also in so-called rock-dusted mines. Following a number of mine explosions it has been reported that the mine was rock-dusted,"" whereas it is probable that only some of the haulage roads had been given a hurried application of rock dust and in most instances not as much as 5 per cent of the mine was really rock-dusted. That is not rock-dusting.Some conscientious, well-meaning mining men have felt that rock-dusting of haulage roads would effectively stop an explosion; however, when shown, through widespread explosions in mines ""well rock-dusted"" according to the above method, that leaving large areas undusted, furnishes paths through which a violent explosion may travel, these mining men have realized the necessity of thorough rock-dusting and have adopted this explosion-prevention method.The Mather Collieries mine, Pickands, Mather and Co., operators, at Mather, Pa., was the first mine in Pennsylvania to receive, full credit for rock-dusting under the new 'stringent ruling of the Pennsylvania Compensation Rating Bureau, the provisions of which require that:"

Feb 1, 1931

By M. P. Board, J. K. Whyatt, T. J. Williams

The U.S. Bureau of Mines has been conducting a series of rock mechanics investigations at the Lucky Friday Mime in the Coeur d'Alene Mining District of northern Idaho. In the present study, the energy release rate (ERR) index was used to evaluate three underhand stope backfill parameters--cement content, density, and placement gap-to determine their influence on rock bursts. This index provides a relative measure of the likelihood of rock bursting for a given rock mass. It is known that the elastic idealization of the rock mass inherent in this method causes underestimation of stope closure and hence underestimation of the influence of backfill on rock bursting. However, this evaluation still showed that (1) changing from present practice to one in which backfill was omitted altogether would increase the ERR by 42 pct and (2) perfect placement of backfill would reduce the ERR below present practice levels by 28 pct. The easiest step toward perfect placement would be elimination of the placement gap, which accounted for half of the difference in ERR between present practice and ideal placement conditions. There was no indication that increasing initial fill strength through increased cement content would affect the ERR.

Jan 1, 1992

By O. P. Hood

The smoke problem means different things in different places . In the neighborhood of industrial plants , especially smelting plants and cement plants , the term " smoke " is applied to material discharged from these plants , consisting of a mixture of solid particles ( dust ) , fume which has condensed from vapors , and gases of various kinds that are produced in the operations . In the ordinary use of the word , however , " smoke" refers to the visible material which escapes from the burning of coal . White smoke usually owes its color to small drops of water which have condensed from the water vapor that it formed in the burning of coal . When smoke is black, the color is due to unconsumed particles of carbon and usually when the smoke problem is spoken of , it is this black smoke produced in the burning of coal that is referred to , Many inquiries in regard to smoke are addressed to the Bureau of Mines , and the following brief summary has been prepared as covering the usual questions . For references to the smoke problem in England , I am indebted to a recent interesting paper on this topic by David Brownlie .

Feb 1, 1922