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By L. J. Kane

While analyzing synthesis gas produced from coal, the Bureau of Mines found that conventional procedures for naphthalene determination were difficult and time consuming. The Bureau developed a rapid and sensitive turbidimetric procedure, which requires only simple instruments and hence can be used in plant-control laboratories. The gas is passed through a saturated aqueous solution of picric acid at 3° to 4° C. whose turbidity is then measured at room temperature. A dispersing agent is added to prevent coagulation of the suspension on warming. Only about 1 mg. (0.015 grain) of naphthalene need be absorbed, and precision and sensitivity are a few ten-thousandths of a grain, or a few hundredths of a grain per 100 cubic feet. The determination can be completed less than 10 minutes after absorption. INTRODUCTION One of the functions of the Branch of Coal Gasification, Bureau of Mines, Morgantown, W. Va., is to develop economical methods for manufacturing, from coal, a mixture of hydrogen and carbon monoxide for producing hydrogen, methane, and other gaseous fuels. This raw gas may contain many impurities, including naphthalene. This impurity is usually determined by first forming naphthalene picrate in a water solution of picric acid, separating the picrate, and titrating the unreacted picric acid or the picrate itself.

Jan 1, 1957

By A. J. Farstad

The current emphasis on energy needs in the United State sand abroad has placed an increased demand on the coal mining industry. The United States is fortunate to have abundant coal reserves. However, coal mining techniques and technology have not kept pace with the increased demand for coal. Consequently, coal mining in the United States continues to be one of the most hazardous industries. One of the daily hazards faced by coal miners is the sudden and unexpected occurrences of roof falls. The research program described in this final report focuses attention on the problems of unstable roof conditions in coal mines and describes prototype equipment which, with further development, has potential of being able to warn miners of impending roof falls in mines. Westinghouse Electric Corporation, Geophysical Instrumentation Systems Group was awarded a contract to develop and test a microseismic roof fall warning system based on general specifications derived from earlier Bureau of Mines research [1], [2]. During the first year of this two year effort (Contract H0242045) the electronic monitoring systems were de signed and built while the second year of the contract was devoted to equipment field testing in working coal mines.

Jan 1, 1976

By I. AITKENS

Quartz maintains a rather conspicuous position among gem stones , despite its being the commonest and, in its natural form, the most easily recognized of mineral substances . This prominence is due primarily to the extensive use of amethyst , which provides stones of the finest violet color , and also to the wide employment of yellow quartz ( citrine ) which is called topaz by jewellers and vies with the true topaz in color and brilliance . Unlike many less costly gem materials quartz is hard and durable .

Mar 1, 1932

By John O. Atkins

[Experiments were conducted by the Bureau of Mines on five types of simuated lunar rock (dacite, tholeiitic basalt, vesicular basalt, pumice, and uluth Gabbro) to study the effects of various simulated lunar environments n their strength and deformational properties. Specimens were tested in an ltrahigh vacuum (UHV) system at pressures ranging from atmospheric down to 0-11 torr and at temperatures of -130°, 20°, and 135° C. All tests were onducted with a servocontrolled testing machine. Rock specimens tested at 0° C in UHV exhibited significantly higher compressive strength and Young's odulus than those tested at 20° C in atmospheric pressure. The magnitudes f increase are related to the porosities and permeabilities of the rock pecimens; high porosity and permeability allow better outgassing and thus nprove surface cleanliness in UHV. The compressive strength generally ncreases but Young's modulus decreases as test environments change from 20° C i UHV to 135° C in UHV. No significant difference was observed in the iysical properties measured at 20° C in LTV and -130° C in UHV. Anisotropy i strength and Young's modulus exist both in UHV and at atmospheric condi¬'.ons with the same symmetry pattern. The orientations of the principal axes iy, however, change from the atmospheric to UHV condition. The results idicate that rock fragmentation in lunar environment will require more ergy than that at 20° C in atomospheric pressure.]

Jan 1, 1974

By W. W. Adams

The extent to which coal mines have installed various types of haulage systems and mining machines is a subject about which there is little definite information available in convenient form for the country as a whole . A few State mine inspectors include in their annual reports such information for their respective States , but uniform data for the United States have not until recently been compiled . Several years ago the Bureau of Mines compiled from one of the standard mining directories * a statement showing the kinds of machines and haulage used in coal mines . The first statement was prepared from the 1918 edition of the directory in which detailed descriptions of coal mines were given . The information presumably related to the calendar year 1917. Similar statements have been compiled from the directories for 1919 , 1920 , and 1922 , the statement for 1921 having been omitted because the directory for that year did not become available . The latest statement is given below and is based upon the directory for 1922. It relates to conditions prevailing in 1921 , and covers a total of 7,088 coal mines . Of these , 5,064 mines . or more than 71 per cent , were using animal haulage . As compared with the total number of all classes of mines , those in the animal - haul age group constituted 71.4 per cent , the percentage having remained practically stationary during the past four years , although the actual number of mines in the group has increased . Rope haulage was reported by 1,066 mines , or 15 per cent of the total , representing a larger number of mines than in 1918 , but a decrease of 2 in the percentage for the group as compared with all classes of mines . Electric haulage was reported by 3,274 mines (46.2 per cent ) , and the number of motors in use was 11,265 . The percentage of mines in this class has not changed materially, but the actual number of mines has shown a gain of about 900 during the past four years . Compressed-air locomotives have not increased either in actual or relative number , the percentage for the past year being but 1.2 . The number of mines using storage- battery locomotives has increased from 3.6 per cent of the total shown four years ago , to 9.8 per cent for last year, the latest figures showing 693 mines with 1,428

May 1, 1922

By Martin H. Stanczyk

The direct dissolution of a typical zinc sulfide flotation concentrate by elevated temperature and pressure leaching was investigated. The concentrate assayed about 55 percent Zn, 32 percent S, 6 percent Fe, and 1 percent Pb and contained minor quantities of copper and precious metals. The influence of various factors on the dissolution of the zinc in acidic and ammoniacal pulps when using oxygen as the oxidant was determined. The tests revealed that the sphalerite was difficult to oxidize. Complete dissolution of the mineral required vigorous and intimate nixing of the gaseous, liquid, and sold phases. The addition of pyrite or sulfuric acid to water slurries of the concentrate was required to obtain a high zinc extraction when leaching under acidic conditions. The quantity of pyrite and acid used was about 0.125 and 0.25 pound, respectively, per pound of zinc sulfide contained in the leach charge. In tests with acid, about 96 percent of the zinc was extracted from the concentrate in 1 hour at 200° C. when the oxygen partial pressure was 75 pounds per square inch gage or higher. Leaching with a continuous flow of air as the oxidant gave results that were almost as good as those obtained when oxygen was used, In tests with air fed through the autoclave at 320 liters per hour, 95 percent of the zinc was dissolved in 1 hour, Acid leach solutions assaying approximately 58 grams Zn per liter and containing Fe, Ni, Cr, and Cu impurities were produced in the better tests. The leached residue consisted essentially of red iron oxide together with substantially all of the lead and precious metals.

Jan 1, 1961

By G. D. Coe

Float-and-sink tests indicate what results are obtainable by gravity separation and rare therefore an invaluable adjunct to most coal-cleaning processes. However, it is difficult to make a direct interpretation of float-and-sink data on coal, and several systems for interpreting them have been proposed. Of these, that developed and used extensively by Bird3/, Yancey4/, and Gandrud5/ is considered by the author to be the most satisfactory. It makes use of four interrelated curves (hereafter referred to as be "washability curves"). These curves were explained by Bird in a paper6/ published in 1923, but his explanation has been regarded by some as not sufficiently

Jan 1, 1938

By W. K. Sawyer

Resistivity, porosity, permeability, and saturation data were obtained on core samples from the Big Injun, Clinton, Gordon, Bradford Second and Third, and Venango Second oil sands and formation factor-porosity relationships were derived using the general form of Archie's equation F = aø-m, where F is the formation factor, ø is the porosity, and a and m are constants that depend on characteristics of the rock. It was found that a and m varied significantly between sands, as did the exponent in the Archie relation I = Sw-n, where I is the resistivity index and S, is the water saturation. The average exponent, n, determined from all data was 50 percent greater at residual oil saturation than at residual water saturation. Samples from each sand exhibited differences in directional resistivity and/or permeability. The Bradford Third sand data showed correlation between resistivity and permeability anisotropy.

Jan 1, 1971

Minerals are vital to any industrialized civilization. Annually, the United States uses more than 4 billion tons of new mineral materials, or about 40,000 pounds per person-about half being mineral fuels and the other half being metals and nonmetallics. Stable and economic domestic mining, mineral, metal, and mineral reclamation industries are essential to the economy. The value of United States energy and processed materials of mineral origin exceds $200 billion annually. Although a number of minerals are imported, especially some designated as "strategic and critical," most U.S. mineral supplies are derived from the domestic mines and processing facilities that you will be seeing, reading about, and visiting as you use this visitor guide. We hope you enjoy your experiences. This pamphlet, a guide to mining and mineral operations that may be observed or visited and some other points of interest relating to minerals, is intended to aid tourists and students who are interested in mining. Some may wish to study our Nation's romantic past; others may plan to enter the minerals industry as a career; still others may have a primary interest in conservation practices. The pamphlet is also intended to aid State and local officials, Chambers of Commerce, and mining firms in answering some of the many questions of tourists and students.

Jan 1, 1976

By Potter G. M.

Ore-dressing tests were conducted on a sample of ore submitted by the Richmond Hill Mining Co. of Lead, S. Dak. as a part of the Bureau of Mines program for investigating potential domestic sources of manganese. Half of the sample was taken from the 300-foot level and half from surface cuts. The problems involved were liberation and rejection of silica and iron and removal of lead, Silver, and gold from the manganese concentrates. Although a portion of the silica and iron oxides was too intimately associated with manganese minerals for rejection by ore-dressing methods, thus limiting recovery of high-grade concentrates, the Richmond Hill ore was found amenable to simple gravity methods of concentration for producing intermediate-grade products. By jigging and tabling, 73.8 percent of the total manganese was recovered in a product that, when sintered, assayed plus 40 percent Mn. Lead, silver, and gold were successfully removed from gravity concentrates by a chloridizing roasting treatment.

Jan 1, 1948

By Kenneth L. Cashdollar

The Pittsburgh Research Laboratory (PRL) of the National Institute for Occupational Safety and Health (NIOSH) and the Mine Safety and Health Administration (MSHA) conducted joint research on dust explosions by studying post-explosion dust samples. The samples were collected after full-scale explosions at the PRL Lake Lynn Experimental Mine and after laboratory explosions in the PRL 20-L chamber and the Fike 1-m3 chamber. The dusts studied included both high and low volatile bituminous coals. Low temperature ashing for 24 hr at 515°C was used to measure the incombustible content of the dust before and after the explosions. The data showed that the post-explosion incombustible content was always as high as or higher than the initial incombustible content. The MSHA alcohol coking test-was used to determine the amount of coked dust in the post-explosion samples. The results showed that almost all coal dust that was suspended within the explosion flame produced significant amounts of coke. Measurements of floor dust concentrations after LLEM explosions were compared to the initial dust loadings to determine the transport distance of dust during an explosion. All of these data will be useful in future forensic investigations of accidental dust explosions in coal mines or elsewhere. Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health or the Mine Safety and Health Administration.

Jan 1, 2006

By Roy L. Soderberg

Ground support for metal, nonmetal, and coal mines was examined through fill placement with a pneumatic stower to increase extraction, reduce ground pressures, and improve general mine safety. Several pneumatically stowed stope-fill products were tested to determine the effects of specific gravity, gradation, moisture, and impact velocity on the in-place density of the stowed fill. Hydraulic sand filling has now served the mining industry for several decades but because of the low density does not always provide ample support to the hanging wall; therefore, the sill and crown pillars sometimes build up excessive stresses that are detrimental to mining. Cementation of a dense fill adjacent to a pillar to allow 100-pct extraction of the pillar, or a fill that can be placed without the use of water and where water is a detriment to rubber-tired mining equipment, was found to be a possible use of pneumatic fill. Placing of coal mine washery products into abandoned underground workings is another possibility in order to completely eliminate surface impoundments.

Jan 1, 1976

By Ernest F. Burchard, J. R. Thoenen

"INTRODUCTION Technically speaking, bauxite is not a definite mineral but a mixture of several minerals belonging to a group of partly consolidated material known as laterite, which have been formed by surface weathering of rocks.The term bauxite is applied to the ore of aluminum, although a substantial amount is used for other purposes, such as a base in certain chemical industries and in the manufacture of artificial abrasives, refractories, and certain cements. Although bauxite has not been classed as strategic it now appears that the domestic supply may be insufficient for expanded defense requirements.Until recently, domestic production of metallic aluminum has been ample to meet requirements, but estimates of pyramiding future needs of the defense program have caused serious attention to be directed to the self-sufficiency of this country, both as to the supply of the raw material, bauxite, and the metallurgical capacity available to convert the ore to metallic aluminum.At the request of the Secretary of the interior, representatives of the Bureau of Mines and the Geological Survey recently investigated domestic resources of bauxite.A preliminary study of published literature and a field investigation disclosed that"

Nov 1, 1941

By R. K. Koch

The Bureau of Mines produced several series of titanium castings in order to investigate the feasibility of producing commercial-grade titanium castings in bentonite-bonded olivine or zircon sand molds. The use of these molds for titanium casting was investigated as a possible alternative to the industrially used rammed graphite process. Parameters investigated were mold mixtures, mulling, gating, venting, drying, and mold washing. The investigators found that castings with superior ductility and fatigue life, compared with rammed graphite castings, could be made by fume-free pro-cesses in molds bonded by western bentonite, using either olivine or zircon sand. Zircon molds were satisfactory for both light-and heavy-sectioned castings. However, olivine molds were suitable only for light-sectioned castings because the mold-metal reaction became excessive during the pouring of heavy-sectioned castings.

Jan 1, 1981

By Michael G. Zabetakis

Investigation of gas explosions usually reveals that the combustible gases have come from transmission and storage facilities or from natural gas or oil wells. However, combustible gases such as methane and hydrogen can derive from biological processes. Hazardous situations have been created in the past by the use of abandoned mines for the disposal of sewage and rainwater, by the interconnection of storm and sanitary sewers, by sealing the openings in manhole covers when repaving the roadway over a sanitary sewer, and by the construction of buildings over or near garbage fill areas without adequately providing for the release of combustible gases.

Jan 1, 1962

By Don Steffa

Drift mining, according to California mining terminology - and it is distinctly a California development - is the blocking out and extraction (breasting) of the auriferous gravels of an ancient buried stream either through tunnels, inclines, or shafts; it is one of the minor divisions of the larger classification known as placer mining. The contribution of each of these divisions and of lode mining to the gross production of gold in California totals as follows:3 [ ] The total amount of gold recovered from the placers of California from 1848, when Marshall discovered the precious metal in the mill race at Coloma, to 1928, was $1,226,515,404. The same period saw a total gold production from all operations of $1,823,562,360.

Jan 1, 1932

By Constantine C. Popoff

During 1946 several limestone deposits near Fortson, Snohomish County, Wash., were examined by the Bureau of Mines. These examinations were part of a long-range investigative program of regional mineral supplies required by the anticipated industrial development of the Pacific Northwest. The .study outlined in the following paper was specifically undertaken to disclose new sources of high-purity limestone and to appraise, their economic aspects. The deposits examined -namely the Galbraith, Climax, and Hi, Hi -are somewhat similar in physical features and geologic environment. They are lenticular and belong to the same formation of metamorphosed sediments that underlies the prominent Whitehorse Ridge.

Jan 1, 1949

By Forrest T. Moyer, Nina L. Jones, Mary B. McNair, Virginia C. Berté

To keep the mineral and allied industries informed of trends in the causes of accidents, and to point out the need for corrective measures, the Bueau of Mines collects, analyzes, and periodically publishes health and safety statistics. This report includes data for 1963 on injury experience, with related employment statistics, at coal mines in the United States. These data are presented in tabular form under the following headings:

Aug 1, 1965

By E. G. Davis

The Bureau of Mines made laboratory-scale experiments to examine the technical possibilities of reclaiming manganese from slags produced by oxygen lancing of high-manganese pig iron. Ferromanganese was added to molten pig iron to yield a 4-to 5-percent manganese hot metal, which simulated a product obtainable from the blast furnace. This was injected with oxygen to reduce the metal to 1 percent or less manganese and form a slag containing about 40 percent manganese. The molten slag was water-quenched, treated with H2SO4) roasted at 660° C, and water-leached to give soluble manganese and iron sulfates. The sulfates were precipitated as hydroxides, converted to the oxide form, and smelted to produce a standard ferromanganese containing 74.6 percent Mn and 0.01 percent P. As an alternate method of manganese recovery, a manganese cell feed was prepared from the leach solutions and electrolytic manganese was produced. Direct smelting of the high-manganese slag resulted in 74.2 ferromanganese meeting ASTM specifications except for phosphorus content. The high phosphorus content of the metal and high slag-to-metal ratio obtained made this approach unattractive.

Jan 1, 1966

By Ted A. Lewtas

The effectiveness of induction fans in ventilating dead headings was studied in the laboratory and underground. The following fan attachments were evaluated: a. Aerodynamic nozzle b. Various lengths of vent tube c. Honeycomb airflow straightener. Various fan locations were also tested. The following conclusions were reached: a. A nozzle on a fan located against the drift wall gives the greatest jet penetration distance. b. Air straighteners are ineffective in increasing jet penetration. c. Induction fans are ineffective in removing contaminants from dead headings without sufficient main ventilation flow.

Jan 1, 1980