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By Albert W. Cox

This paper, one of a series prepared for the United States Bureau of Mines discussing the methods used in mining, crushing, and grinding materials for cement manufacture, deals particularly with the methods used at the Security plant of the North American Cement Corporation. These papers are designed to disseminate technical information regarding the methods used. The cost tabulations represent local operating expenditures only and not total production costs. It is recognized that publication of, total production costs might in many instances cause embarrassment to individual producers as well as to the industry as a whole. On the other hand, operating costs are essential to the technical discussion and study of methods employed. The attention of the reader is specifically called to this differentiation in order that no misunderstanding of the scone of the cost tabulations shall ensue.

Jan 1, 1932

By T. E. Hill

The Bureau of Mines investigated the possibility of physically separating Missouri and Minnesota granites into commercially usable fractions of feldspar, quartz, and mica by mineral dressing techniques. The probability of r covering a feldspar fraction from raw granite suitable for commercial uses was developed through correlation of the iron oxide content by extensive petrographic studies. This probability evaluation also included Wisconsin granites and a high-feldspar iron ore concentration tailing from Missouri. Laboratory recoveries of feldspar and quartz were on the order of 80 percent. Mineral content of each fraction was generally over 95 percent, indicating excellent response to separatory techniques, Acid leaching of feldspar and quartz concentrates to remove iron oxide improved the grades chemically; however, occluded iron oxide particles in the leached products prevented attaining top grades of feldspar. Mica was removed as scrap grade at low recoveries. Each concentrate conformed to some category of commercial feldspar, quartz, or mica.

Jan 1, 1969

By K. E. Tame

A resume of the history and state of the art of physical beneficiation of uranium ores is presented along with a detailed description of research on concentration of uranium ores by attrition grinding. The information on flotation, gravity concentration, electronic sorting, and selective grinding was gathered to complement the study of attrition grinding methods. Both dry and wet grinding procedures were investigated as potential methods of upgrading a variety of ore types, ranging in grade from 0.02 to 0.42 percent U308. A Mardun4 disintegrator that employs high-speed rotating paddles in a cylindrical shell lined with interrupter bars was used in most of the dry grinding studies. Attrition scrubbing devices, which impart a violent mixing or attritioning action to ore pulps, and cylindrical mills, employing rods or punchings as grinding media, were used in the wet grinding tests.

Jan 1, 1961

An active list of permissible explosives was published in December 1936 as part of Bureau of Mines Report of Investigations 3324, under the title "Active List of Permissible Explosives and Blasting Devices Approved Prior to July 31, 1,936." This list included 170 brand names. Changes in the list that have been authorized to June 30, 1937 placed 35 additional brands of permissible explosives on the active permissible list as a result of tests, changes in brand names, or transfer from the inactive list. Ten permissible explosives were transferred from the active to the inactive list. The present list contains 196 brand names, one explosive having been placed on the list subsequent to June 30, 1937. The brand names of the permissible explosives placed on the active list are as follows: [ ]

Jan 1, 1937

By R. W. Smith

The Bureau of Mines has been engaged in a systematic evaluation of the thermodynamic properties of combustion gases. These studies were designed to provide basic thermodynamic information of high accuracy, facilitating the theoretical study of flame and combustion phenomena.4 This report is the fifth of a series5/ presenting results of the study for particular fuel-oxidant systems. These calculations have as their objective the constant pressure flame temperature of acetylene-air for a range of pressures.

Jan 1, 1954

By Lito C. Mejia

Diesel-powered equipment operating in a gassy underground mine could conceivably ingest a methane-air mixture from the mine atmosphere that could cause the diesel engine to overspeed, or exceed its rated speed. Engine overspeed, particularly if extreme (engine runaway), could result in personal injury, a possible mine explosion, and/or catastrophic engine failure. In this report, the Bureau of Mines reviews the literature on the potential hazards of methane-induced diesel engine overspeed. Also included are the Bureau's findings from consultations with representatives of the diesel engine industry to determine the specific engine behavior that could he expected under the overspeed condition. The report summarizes data on mine accidents involving methane, discusses results of tests on the compression ignition of methane in diesel engines, and examines fuel governors and intake-air-cutoff devices, two kinds of devices used to prevent overspeed. Analysis of the information gathered suggests that the conditions necessary to cause a diesel engine to overspeed uncontrollably are not likely to occur, particularly if the engine is equipped with flame-proofing devices. The available literature and lack of actual overspeed case histories suggest that the safety devices currently in use are sufficient to prevent diesel engine overspeed.

Jan 1, 1984

By E. G. Davis, H. P. LeVan, L. S. Smith

Leaching of a Georgia umber ore when using both ferrous sulfate and pickle liquor was studied in the laboratory . The ferrous sulfate content of the leach solution was the major factor affecting the extraction of manganese from the ore . Time , temperature , and the sulfuric acid content of the leach solutions had relatively little effect on leaching of manganese from the ore ; however , these factors did affect the amount of iron extracted from the umber and/or precipitated from solution . Simulated countercurrent leaching of the ore with pickle liquor containing 130 gpl (grams per liter ) ferrous sulfate ( 48 gpl ferrous iron ) produced a pregnant solution having 16 gpl manganese and 41 gpl iron . Filtration tests of the leach slurries indicated that separating the leach solution and solids by vacuum filtration was impractical , whereas pressure filtration was feasible when the cake thickness was limited to about three- fourths of an inch . Fired pellets of the filter cake yielded a firm , hard product analyzing 56 percent iron and less than 0.1 percent sulfur .

Jan 1, 1964

By A. C. Fieldner, G. W. Jones

Tests were made at the Government Fuel Yard , operated at Washington , D. C. by the Bureau of Mines , Department of the Interior , in order to determine and improve the adjustment of the carburetors on the trucks used for transporting coal from the Fuel Yard to the different Government buildings in Washington . The tests were made possible through the hearty cooperation of G , S. Pope , engineer in charge of the Fuel Yard . Joseph Burrows and A. E. Foote of the garage department assisted during all the tests and supplied information on the mileage obtained by the trucks for the months preceding and succeding the time the tests were made . The Mack trucks used range in capacity from 2-1/2 to 7-1/2 ttoonnss .. The majority of the carburetors were Stromberg G- 3 type , as shown in Table 2. During the winter months , when the demand for coal is heavy , from 30 to 35 trucks are used . At the time the tests were made , only about ten of the trucks were in daily use , owing to the small demand for coal during the summer months , and scarcity due to labor conditions . Samples of the exhaust gas were taken on the trucks kept in service for summer hauling in order to determine the carburetor adjustment as used . Changes were then made to a more economical adjustment wherever possible , without sacrificing flexibility of operation and power . In every case the adjustments were maintained for maximum power , but were adjusted to the leanest position to give that power . In all but one case the carburetors were found to be adjusted too rich for maximum power and economy . These results are considered in detail in a later part of this report .

Jun 1, 1923

By K. K. Kelley

The heats of formation of two lead vanadates (Pb2V207 and Pb3V208) and manganese vanadate (MnV206) were determined by hydrochloric acid solution calorimetry, supplementing previous Bureau of Mines measurements of the vanadates of calcium, magnesium} and sodium. Heat and free energy data for 11 vanadates were assembled on a common basis. The stability of comparable vanadates (with respect to the oxides) increases in the following order: Magnesium, manganese, lead, calcium, sodium.

Jan 1, 1963

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 Raymond L. Carpenter

The thermal conductivity, electrical resistivity, and Seebeck coefficient for nine compounds, based on the formula for enargite Cu3AsS3, were measured in a search for efficient materials to be used in thermoelectric generators or refrigerators. Results indicate that one of these compounds, Cu3SbSe4, has thermoelectric properties approaching those of bismuth telluride. An investigation of the effect of adding small quantities of tellurium to Cu3SbSe4 and Cu3SbS4 in order to improve their properties also was made. A figure of merit of 2.1 x 10-4 °C-1 was obtained for Cu3SbSe4 + 0.1 percent tellurium.

Jan 1, 1963

The coal reserve base is defined for coalbeds having sufficient thickness for underground mining within a depth range compatible with economic recovery. The reserve data are compiled by the Federal Bureau of Mines by updating and reevaluating previous estimates of the U.S. Geological Survey, State geological surveys, and others. Through the application of computer techniques, the tonnages are compiled by State, county, coalbed, and rank. Coal reserve base is allotted to sulfur categories by a statistical apportionment of data from available Bureau of Mines reports and records. The coal reserve base in those States east of the Mississippi River, minable by underground methods, is estimated to be 169 billion tons in coalbeds greater than 28 inches in thickness to a maximum depth of 1,000 feet. Excluding those coals in reliability categories other than measured and indicated, the underground reserve base includes 162 billion tons of bituminous coal and 7 billion tons of anthracite. Of the total, 27 billion tons contains 1.0 percent or less sulfur. Most of this low-sulfur coal is in the southern Appalachian area. Approximately 16 percent of the underground reserve base is without available analyses. Included in this report is a glossary of terms applicable to a classification system for coal resources and reserves. The purpose of this system is to provide a common yardstick for determining coal resources and reserves.

Jan 1, 1974

By Lawrence W. Sott

This Bureau of Mines report presents several factors that currently enter into the design, manufacture, and testing of windows and lenses used in explosion-proof enclosures. Emphasis is also given to the sealing concepts for lenses. Criteria for adhesives and sealants are suggested based on the survivability of an explosion-proof enclosure as a structure, rather than upon the minimum material properties of its constituents. Procedures for surface preparation of adherends are also discussed.

Jan 1, 1982

By Joseph D. Davis, G. S. Scott, Palmer B. Place

In the course of investigations made by the Bureau of Mines in cooperation with the Trent Process Corporation, into the properties of mixtures of oil and coal, a comparative study was ma.de of the 'behavior of these mixtures and their cons ti tuents on destructive distillation. Mixtures of a petroleum oil and bitminous coal were first distilled under carefully controlled conditions, and then charges of the eame oil and coal were distilled separately under similar conditions. The quantity and quality of the distillation products were determined, and. resul. ts were compared. This comparison furnished a basis tor judging whether grea, ... er values in products can be obtained by distillation of oil and coal in mixtures than· b:, their separate distillation. In making the mixtures, the method used in t~e Trent process for cleaning coal was followed. The paste or plastic emulsion of oil and coal obtained is called "amalgam".••• When finely pulverized wet coal is mixed with approximately one-third its weight of. oil and agitated with a large excass of waj;er, the coal and oil agglomer-. ate to form a paste or amalgam. A large portion of the extraneous ash original.17 in the coal remains suspended in the water, with which it can be decanted from the amalgam. Ir the latter is now thoroughly drained and kneaded after the manner ot working butter, most of the excess water enclosed can be removed. This, .in brief, constitutes the Trent process for cleaning coal, The effectiveness of the process for cleaning coal has been studied••••. by the Bureau, and the results of the study show, in general, a high ash reduction an:l good recovery of combus ti bl e f'rom coals of medi ,mi and hi~ rg,nk. With coals of tht lowest rank, such as li@!Rlites, the process is only moderately auccessf'ul, owing to the difficulty attending the preparation of coherent amalgams, Oil losses to wate~ and refuse are small, and apparently it would be practical to rotate the same oil in the cleaning process if some efficient method were devised for recovering it from the amalgam, so a distillation process naturally suggested itself.

Dec 1, 1921

By Laird Crocker

This report describes a study of beryllium recovery from sulfate leach liquor by di-2-ethylhexyl phosphate (EHPA) solvent extraction in conjunction with caustic stripping. The work was one phase of Bureau of Mines research on process development for Spor Mountain, Utah, ores. Solution for the solvent extraction studies was prepared by sulfuric acid leaching of ore containing 0.6 pet BeO, Before solvent extraction of beryllium, the leach liquor was treated to prevent coextraetion of iron by either (1) removal of ferric iron by amine solvent extraction or (2) reduction of ferric iron to nonextractable ferrous iron by treatment with sulfur dioxide. Beryllim was extracted from the aqueous leach liquor by countercurrent multistage contacting with a kerosine solution of EHPA. The loaded organic solution was stripped with sodim hydroxide solution. Subsequently, beryllium hydroxide was precipitated by boiling the sodium beryllate strip solution and converted to beryllium oxide of 98 pct BeO-grade by calcining. Material of this grade can be directly processed into beryllium-copper alloy or be used as starting material for further refining to produce high-purity, nuclear-grade beryllium. Over 90 pct of the beryllium contained in the leach liquor was recovered as beryllia.

Jan 1, 1963

By Marvin L. Whisman

Several parameters controlling the reproducibility of tritium determina¬tion in organic compounds by liquid scintillation counting were evaluated by the Federal Bureau of Mines. These included optimum volume of scintillator solution for maximum counting efficiency, reproducibility of counting a sealed commercial standard and comparison with duplicate counts on laboratory-prepared samples. The error introduced by using microliter pipets, optical differences in counting vials, reproducibility of counting organic samples where quenching is a factor, reproducibility of counting laboratory-prepared samples with an added internal standard, optimum ratio of internal standard activity to sample activity, effect of sample volume upon counting efficiency, count rate at which coincidence losses become apparent, and reproducibility of organic compound radioassay by the standard addition technique are outlined. From the evaluation of these parameters, a technique that can be applied routinely to organic compounds containing tritium has been established, and details are included in this report.

Jan 1, 1961

By O. M. Schaus

This paper is one of a series, prepared by the Bureau of Mines and deals with the Montreal mine, one of only two active properties in Wisconsin on the Penokee-Gogebic range. The purpose of this paper is to describe the conditions of occurrence of iron ore in a particular property and to present sufficient details of equipment and production methods to convey to the unacquainted operator a correct idea of the mining practice.

Jan 1, 1930

By F. A. Skirvin

Purification techniques were investigated for removing low-level metallic impurities from tungsten hexachloride. These techniques included distillation) fused-salt scrubbing) zone refining) and adsorption. Fractional distillation of tungsten hexachloride was found to be an effective purification method. The impurity levels of molybdenum) iron) nickel) copper) magnesium) and manganese were reduced to provide a tungsten halide sample which contained a total of less than 10 ppm detectable metallic impurities. Purification by fused-salt scrubbing of tungsten hexachloride in a lithium chloride-potassium chloride eutectic produced a hexachloride product which was of approximately the same quality as that obtained by distillation. Zone refining and adsorption did not appear to be as effective as distillation or fused-salt scrubbing.

Jan 1, 1967

By H. Winkelmann

The author, who himself has worked inn the field with various types of torsion balances, expresses in the article his experience with the recently marketed Haff-Torsion-Balance. The advantages of practical work with Haff?s s torsion balance as compared with other types are mentioned. In spite of low weight and corresponding small dimensions (Model M = 23.5 kg., Model Al = 11.5 kg.) the sensitiveness is not less than that in the largest instruments. It is at 1.10-9, which is proved by calculations. A comparison with the corresponding values of other types of torsion balances (Eötvös, Askania, Gepege) is given. The mechanical features of the instrument are briefly described, and the balance is illustrated by a, cross section of it. -- W. Ayvazoglou. DETERMINATION OF THE ELEMENTS OF THE MAGNETIC AND GRAVITATIONAL FIELDS INDUCED BY AN INFINITELY LONG HOMOGENEOUS CYLINDER By G. A. Gamburzeff Gerlands Beiträge zur Geophysik, Band 19, Heft 2/3 Leipzig, 1928, pp. 210-230. The present work is a. contribution to the quastion of the reason for the magnetic and gravitational anomalies in the government of Kursk (Russia).

Jan 1, 1929

By John W. Frey

This paper presents one of a series of digests of foreign mining legislation and court decisions that is being prepared in advance of a general report relative to the rights of American citizens to explore for minerals and to own and operate mines in various foreign countries . This interpretation of the mining law of Australia was first compiled from the best information available in Washington; it was then sent to the American Consulate General , in Australia, where through the direction of Thomas H. Robinson , American consul in charge , it was submitted for criticism to the mining authorities in the various States of Australia , whose suggestions have been incorporated in this digest .

Sep 1, 1930