Search Documents

By R. A. Guidotti

The Federal Bureau of Mines has studied the reaction of oxides of columbium, vanadium, and tantalum with ammonia in vertical, gas-solids reactors at temperatures ranging from 300° to 1,300° C with the goal of preparing nitride intermediates for subsequent preparation of the metals by a thermal-decomposition step. The best nitride conversions were obtained in nonmetal reactors. With Cb205, V2O3, and V205 , low-temperature maxima in reaction rates occurred at 800°,800°, and 450° C, respectively, during oxynitride formation (in A1203) at 1 atm of pure ammonia. Conversion of the oxynitride, in a second step, to the mononitride was optimum at 1,200° C for columbium and 1,050° C for vanadium. In the case of Ta205, the rate of reaction to form Ta3N5 (in a single step) was highest at 900° C, where the presence of up to 5 percent methane was found to be beneficial; improved results were obtained by conducting the nitriding in a rotary kiln. Optimum space velocities (in the vertical Al203 reactor) ranged from 5,280 hr-1 for Cba205 to 7,950 hr-1 for V203. Oxide particle size had little effect upon reaction rates. Under fully optimized conditions, products containing less than 1 percent oxygen were readily obtained in under 6 hours.

Jan 1, 1975

By F. W. Wood

Ingots of zirconium and other highly reactive metals such as titanium and hafnium produced by the consumable-electrode arc-melting process require conditioning before forging or rolling. A nondestructive, arc-conditioning technique has been developed as a substitute for lathe conditioning. The technique employs en electric arc under an inert atmosphere to fuse surface metal on the sidewalls of ingots without seriously affecting the general quality of the ingots. Advantages of the practice are Increased yields, lower accumulation of inferior scrap, and actual cost savings. The work cited in this report was done on zirconium. INTRODUCTION The consumable-electrode arc-melting process as practiced at the Bureau of Mines3 4/ has proved to be a technique for producing sound, homogeneous, commercial-size ingots of zirconium and its alloys. Ingots produced by this process, however, have as a characteristic a layer of partly fused metal on the sidewall to a depth of 3/16 to 3/8 inch. To prevent extension of surface imperfections during forging, the ingots are ordinarily conditioned by removing defective material in a lathe. If the metal were less reactive or the requirements less severe, the machine chips could be recycled and remelted. However, zirconium, being so oxygen sensitive, is contaminated by merely being machined despite extensive cooling of the tool bit. Further, being contaminated with oxygen, the chip metal upon remelting is 10 to 25 Brinell-hardnese numbers harder than the ingot from which it was machined. For this reason, the ingot specifications for naval reactor use have prohibited remelting machine chips, except as required for starting pads. Again, were zirconium less costly or less in demand this ever-increasing pile could be burned to oxide and recycled through the Kroll sponge process. Economics do not favor this, as melting feed stock has an estimated increase In value over oxide of about $8.80 per pound of contained zirconium. The efforts of the Bureau to solve the problem have been directed along two lines: To reduce the contamination of the machine chips produced and to reduce the quantity of the chips produced. This paper presents the technique developed to reduce the quantity of chips produced by arc-conditioning the remelted ingot.

Jan 1, 1955

By F. D. Wang

The Bureau of Mines has developed a computer program for evaluating pit slope stability by the finite element stress analysis and limiting equilibrium method. The program includes the finite element method of stress analysis using triangular elements, finite-element model mesh generation, plotting of the model mesh and stress contours, calculation of a factor of safety along a circular or a plane failure surface, and location of a critical circular failure surface. Instructions for preparation of input data, an example problem, and the program listing are presented.

Jan 1, 1972

By G. Nuñez, M. A. Pathak, C. F. Stanley

"Holographic interferometry is a non-destructive technique to detect small deformations1 of an object. It is a whole-field technique· with an accuracy of a few microns. An adaptation of holographic interferometry is time-averaged holographic interferometry which is particularly useful in detecting small vibration amplitudes of an object under investigation. Its application to biological tissue is especially difficult due to the combination of (a) the high sensitivity of the technique, and (b) the tendency of these objects to deform excessively, or move during the testing period. (This is also compounded by the changing moisture content of the tissue surface.)Ideally, a pulsed laser and fast-acting thermoplastic film camera could be chosen to overcome these difficulties, but the total equipment cost could exceed $75,000. In this paper we describe our relatively economical method to apply time· averaged holographic interferometry to an excised animal lung, utilizing holographic plates and a mechanically-shuttered continuous-wave Argon laser.EXPERIMENTAL METHODThe schematic of the experimental setup is shown in Fig. 1. The holographic equipment, including the laser, is fixed on a 3 ft x 6 ft x 4 in. honeycomb holographic table. This table is functionally similar to one described by Mark and Horsch2 which can be constructed for about one thousand dollars. The holographic table itself rests on six inner tubes to absorb floor vibrations. All unnecessary vibrations must be reduced to preserve the quality of the holograms. A laser beam from a 0.5-watt continuous-wave Argon laser is split by a circular variable beamsplitter (Newport Corporation Model 50GOOAV.1) into two beams, i.e., an object beam and a reference beam. The object beam is again split into two beams of equal intensity by a 50150 beamsplitter (Newport ·Corporation Model BS.1). These beams are optically filtered and expanded by spatial filters (Newport Corporation Model 910) to cover as much area of the object as possible. Soft biological tissues exhibit low reflectives, resulting in a relatively high reference to object beam ratio of roughly 5 : 1 at the holographic plate."

Jan 1, 1989

By J. B. Janus

This Bureau of Mines publication updates a series of reports on the quality of coal purchased under specifications for Government use. Listed are analytical data on the composition and quality of tipple and delivered samples of coal collected during the period July 1975 through September 1976.

Jan 1, 1977

By L. C. George

The Bureau of Mines measured the vapor pressures of selected mixtures in the binary systems CdCl2 ?SnCl2, CdCl2 -ZnC12, PbCl2 ?SnCl2, and PbCl2 -ZnCl2 by the static pressure method. These data were evaluated by the second-law (sigma-plot) method. Equations expressing the vapor pressures and the heats and free energies of vaporization as functions of temperature are given.

Jan 1, 1969

By C. E. Hennig

On January 1, 1959, the United States had 313 petroleum refineries with a total installed crude-oil throughput capacity of 9,819,846 barrels per day, according to the Bureau of Mines annual survey. Compared with a year ago, this represents a net decreased of five in the number of slants mild a net increase in capacity of 412,139 barrels per day. The continued increase in total capacity and decrease in number of plants raised the average capacity of a refinery to a new high of 31,373 barrels per day. During 1958 total capacity increased in every refining district except the Louisiana Gulf district, which showed a 2-percent decrease due mainly to the retirement of the American Oil Company's plant at Destrehan, La. The largest increase, 14 percent, occurred in the Texas Inland district followed by a 12-percent increase in the Arkansas-Louisiana Inland district. At the beginning of 1959 the industry was building facilities that would add 108,400 barrels per day to crude-oil capacity. It also had under construction a capacity of 226,100 barrels per day as replacement. On January 1, 1959, no new refineries were under construction.

Jan 1, 1959

By W. W. Adams

Reports received by the Bureau of Mines, Department of Commerce, from State mine inspectors, for November, 1930, showed that 219 men were killed in the coal mines of the United States during the month, an increase of 25 over the previous month and 33 over November, 1929. On the other hand the production of coal decreased, the output of 43,329,000 tons in November being 8,397,000 tons less than in October and 9,005,000 tons less than in November a year ago. The larger number of fatalities accompanied by a smaller output of coal resulted in a higher death rate4 per million tons in November than in the same month last year or in October, 1930. The November rate was 5.05, as compared with 3.55 for November, 1929 and 3.75 for October, 1930. The increase in the rate for the industry as a whole was chargeable entirely to bituminous mines,, as the anthracite mines had fewer fatalities in November than in either of the previous months to which reference has been made. Reports for bituminous mines alone 'allowed that accidents at class of mines resulted in a death rate of 5.12, based on 195 fatalities and a production of 38,122,000 tons. This rate indicated an increase of 55 per cent over the rate for October, of the same year, and 72 per cent over the rate for November, 1929. The October record was 146 fatalities and 44,150,000 tons, and that for November a year ago was 138 deaths and a production of 46,514,000 tons. Twenty-four deaths occurred at anthracite mines in November, 1970: the output of coal was 5,207,000 tons, hence the rate was 4.61 per million tons. During the corresponding month a year ago there were 48 deaths and 5,820,000 tons of coal produced, which indicated a death rate of 8.25. In October, 1930, the death rate was o.34; based on 48 deaths and 7,576,000 tons.

Jan 1, 1930

By George S. Rice, J. W. Paul, E. H. Denny

Data assembled by the Bureau of Mines , coupled with requests from coal companies , have emphasized the desirability of establishing standardized specifications for brattice cloth with particular respect to durability and fireproofing . Brattice cloth is a canvas or other material , often covered with some fireproofing composition , which is used extensively in coal mining for temporarily deflecting air into pillar workings and maintaining ventilation at the working faces . These specifications will be established , it is planned , through a cooperative program in which the U. S. Bureau of Standards will make a series of tests of various brattice cloths treated with respect to fire- resisting qualities and the U. S. Bureau of Mines will continue to assemble field data on the use of brattice cloth . Plans now are being made for this cooperative work. Without attempting to make a complete survey , the Bureau of Mines has made preliminary studies and investigations , and verious representative coal - mining companies have furnished detailed information . The information thus gained will be used as the basis for the cooperative investigation , but the Bureau of Mines would welcome additional information from mine operators on the character and weight of brattice cloth , conditions of use , durability , quantity employed and price . Such information should be sent to the Director , Bureau of Mines , Washington , D. C. The mine operator is interested in procuring at reasonable cost a brattice cloth with lasting fireproofing quality and of as great durability and strength as possible . There has been a lack of assembled data and knowledge regarding the subject , but the Bureau of Mines feels that this lack of knowledge may be overcome if the coal -mining companies will lend their hearty support to the cooperative investigation and submit information relative to the use of brattice cloth in their own properties . Information contained in this report is based on data obtained from coal operators in bituminous districts of Pennsylvania , Alabama , Utah , Indiana , Illinois , Colorado and Nova Scotia .

Feb 1, 1923

By R. F. Abernethy

A modified Unterzaucher method was applied to the direct determination of oxygen in coal. Coal samples were pyrolyzed in a nitrogen atmosphere, and the gaseous oxygen compounds liberated were converted to carbon monoxide by a platinized-carbon catalyst at 9000 C. After passing over heated copper and through a tube containing soda-asbestos and magnesium perchlorate, the purified carbon monoxide was oxidized to carbon dioxide by iodine pentoxide--liberating an equivalent amount of iodine. The iodine was titrated with 0.02 ~ sodium thiosulfate; in a few tests the weight of carbon dioxide produced was determined. Direct oxygen determinations of coal included organic oxygen from the coal substance, plus a small quantity of inorganic oxygen derived principally from carbonate minerals and from combined water of silicates in the mineral matter. The influence of mineral matter on the direct oxygen determination was investigated by testing (1) untreated coal, (2) demineralized coal from which most of the mineral matter except pyrite was removed by treatment with hydrofluoric and hydrochloric acids, and (3) coal samples treated with dilute hydrochloric acid.

Jan 1, 1966

By C. W. Dwiggins

This report describes the development, theory, and application of techniques and instruments for quantitatively determining nickel, vanadium, and iron in oils, using direct, X-ray emission spectrographic methods (5, 6).3 The methods developed apply to petroleum and other oils as well as some specific fractions of oils. The quantities of nickel, vanadium, and iron in various petroleums are of practical and theoretical interest. Even traces of nickel and vanadium may poison cracking catalysts, and X-ray methods have been used for determining nickel in such catalysts (7). At least parts of the nickel and vanadium occur as metal-porphyrin complexes, a fact which may have considerable bearing on knowledge of the origin of petroleum.

Jan 1, 1962

Improve safety at mineral operations that use cyanide leach solutions to recover precious metals from finely ground ores, Approach Provide an alternative, non-acidic means of cleaning processing systems such as the State-of-Maine filter system, thereby reducing the exposure of workers to toxic hydrogen cyanide gas (HCN), The Problem Many gold and silver mining operations use cyanide solutions to dissolve gold and silver from ores. The precious metals frequently are recovered from pregnant leach solutions by the Merrill-Crowe recovery process, whereby gold and silver is precipitated with zinc dust. When that method is used, suspended particles in the leach solution must be filtered out before zinc precipitation can occur. This filtering is accomplished with small packaged plants, such as the State-of-Maine (SOM) filtering system. Unfortunately, the filters become clogged with calcium carbonate scale after about 2 to 10 days of operation and must be cleaned before further precious metals recovery operations can continue, Cleaning the system is a hazardous task because the acid is not compatible with the alkaline cyanide leach solutions, and toxic hydrogen cyanide (HCN) gas may be produced when the acid and solution are mixed. That gas, if breathed or contacted with the skin, can cause cyanosis which may induce nausea and even asphyxia and death. To reduce this danger, the Bureau of Mines has devised a safer method of cleaning clogged filters,

Jan 1, 1986

By W. A. Cole

This report covers the preliminary phase of an investigation of clays, shales, and certain rocks in Wisconsin to determine the feasibility of processing lightweight aggregate in the State. The study was extended to include rotary-kiln testing of a limited number of shale samples, and to an appraisal of the Maquoketa shale resources in eastern Wisconsin. A total of 45 samples of clays, shales, and other argillaceous rocks of Wisconsin were tested. The lower Maquoketa shale is the only material found to date that offers possibilities as a source of material that can be processed in a rotary kiln for lightweight aggregate. Bedrock occurrences of the Maquoketa shale are found in the eastern and southwestern parts of the State. The populous southeastern region of Wisconsin presents a large potential marketing area for lightweight aggregate. For this reason special study was directed to the Maquoketa shale in the eastern district.

Jan 1, 1961

By Charles Findlay, Stephen Krickovic, J. E. Carpetta

As one of its projects for degasification of major panels of coal prior to mining within them, the Bureau of Mines conducted methane emission studies during development of a set of three headings 1,800 feet in a major coal panel (2,700 by 3,500 feet) which had been completely isolated by sets of main headings for 12 months in the Federal No. 2 mine (Pittsburgh coalbed) in northern West Virginia. Similar emission studies were conducted in the development of two sets of main headings in virgin coal areas nearby. Comparing the two sets of data indicated that the isolated coal panel had been degasified by approximately 70 percent.

Jan 1, 1973

In 2007, a total of 14,871 mining operations reported employment data to the Mine Safety and Health Administration (MSHA).1 Almost half (48.4%) were sand and gravel mines, followed by stone mines (31.2%), coal mines (13.7%), nonmetal mines (4.9%), and metal mines (1.9%).

Aug 1, 2009

By G. S. Rice, R. V. Wheeler

"FOREWORDThe cooperative mine safety research program was carried on successfully in the year 1930 in a manner similar to that described in the report for 1929It is believed that the results of such fundamental work as is being done are unquestionably of great benefit in their application in coal-mining operations, in the saving of life and health of minera. The research result compared and checked by investigations in the two organizations, and further by large-scale tests, as in the Experimental Mine, give confidence to mine operators, miners and State mining officials in the findings of the various researches.The annual report of the contact officers of the United. States Bureau of Mines and the British Safety in Mines Research Board to the Director of the Bureau and the Chairman of the Board respectively, follows:Annual Reports for 1930 To: The Director, Bureau of Mines.The Chairman, Safety in Mines Research Board."

Sep 1, 1931

By Albert S. Konselman

This paper describes the mining methods and operating costs for 1938 at the South Burns shaft, situated in the Cripple Creek district, Colorado. The shaft is operated by Golden Conqueror Mines, Inc., through which portions of the properties of the Acacia Cold Mining Co., The Free Coinage Gold Mining Co., and The United Gold Mines Co. are worked under lease. During 1938, 30,773.61 dry tons of ore averaging $9.59 in gold per ton was mined. Of this, 10,138.439 tons averaging $10.65 per ton was produced on company account, and 20,635.171 tons averaging $9.05 per ton was produced by "split-check" lessees.

Jan 1, 1940

By W. W. Adams

"The third annual safety contest for plants producing sand and gravel, which was conducted in 1911 by the United States Bureau of Mines in cooperation with the National Sand and Gravel Association, registered further progress in safety as compared with the two previous annual contests. Both the accident-frequency rate and the accident-severity rate were reduced.The period covered was the calendar year 1931; sixty plants participated, and 17 States were represented by the participating companies.The contest covered accidents and man-hours worked by all men at the participating plant who were employed by the same company; and it included work up to the point of delivery of the material directly to the consumer or to an independent agency of transportation--in other words, to the point of relinquishment of control of the material by the producer.The purpose of the yearly contests for producers of sand and gravel is to aid in the promotion of safety among the employees and in the reduction of accident costs to the companies. The contests develop friendly rivalry among the various plants and among the employees of individual plant in a concerted effort to prevent accidents.Two safety trophies are awarded annually, both of which are provided by Rock Products magazine. One of the trophies is for the host safety record among plants that were in operation the contest year 100,000 or more man-hours; the other trophy is for the best among plants that were in operation lees than 100,000 man-hours. Awards and the relative standing of the various plants are based upon statistical compilation by the Bureau of Mines of accident reports and employment reports furnished by the enrolled companies. are summarized at the close of each year, and the summaries are submitted to each company concerned for certification as to the accuracy of the summary and the completeness of the company's reports from which the summary was prepared. When the summery is returned signed by an official of the company, the records are considered to be a trustworthy basis for determining the relative standing of the various plants. The position of each plant is determined by its accident-severity rate; that is, the number of days of disability resulting from accidents for each 1,000 men-hours of work done by all employees at the plant."

Aug 1, 1932

By Richard A. Winters

In 1985 at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied 9,400 acres of the 10,005-acre Duncan Creek Wilderness Study Area (ID-111-78) in order to evaluate the mineral resources. The study area is located in Owyhee County, 10, about 36 miles southwest from Bruneau, ID. No mining districts are in the study area, nor were any mines or claims recorded or found. The southern half of the area was covered by oil and gas lease applications, all of which were cancelled prior to June, 1985. No economic concentrations of minerals were found in the study area. INTRODUCTION This report describes the USBM (U.S. Bureau of Mines) portion of a cooperative study with the USGS (U.S. Geological Survey) to evaluate mineral resources and potential of the Duncan Creek study area at the request of the BLM (U.S. Bureau of Land Management). The USBM examines individual mines, prospects, claims, and mineralized zones, and evaluates identified mineral and energy resources. The USGS evaluates potential for undiscovered resources based on areal geological, geochemical, and geophysical surveys. Results of the investigations will be used to help determine the suitability of the study area for inclusion into the National Wilderness Preservation System. Although the immediate goal of this and other USBM mineral surveys is to provide data for the President, Congress, government agencies, and the public for land-use decisions, the long-term objective is to ensure the Nation has an adequate and dependable supply of minerals at a reasonable cost.

Jan 1, 1986

By R. E. Hall

When the criterion for control of scale prevention on the evaporating surfaces is made the conditions in the concentrated boiler water, then this control becomes an exact operation amenable to an accuracy commensurate with all other operations in the boiler room. The responsibility in boiler water conditioning, however, includes more than clean surfaces. Corrosion in feed lines, economizers and the boiler is a function of the condition of the later, and must be controlled. Steam line and turbine blading deposits must be obviated by the system of conditioning. By the chemical treatment employed, the amount and character of noncondensable uses in the steam must be controlled in accordance with the intended use of the steam. All. in all, the responsibility in boiler crater conditioning ends not with the entrance of the water into the boiler but with the passage from the boiler nozzle of steam, the dryness and rarity of which are defined by the uses to be made thereof. A clearer conception of the scope of boiler water conditioning can be obtained by reference to a diagram of the surfaces (Figure 1) at which it functions. Consideration of this diagram leads to the following outline for the problems of boiler water conditioning: (a) Prevention of scale formation on surfaces (1) In contact with water but at which no evaporation occurs. (2) At which evaporation is occurring.

Jan 1, 1926