Search Documents

By J. S. Miller

The Bureau of Mines conducted surface tests to determine the feasibility of using liquid explosives for underground rock fracturing. The effects of configuration, confinement, length, critical layer thickness, and fracture-propping sand on detonation and explosive propagation velocity of desensitized nitroglycerin were studied, using polymethyl methacrylate and glass-plate reservoirs through lengths from 3 to 12 ft, with explosive-layer thicknesses from 0.1875 to 0.0312 in and in aluminum tubes 8 ft long with diameters from 2.000 to 0.125 in. Interval and continuous detonation velocity data were obtained. Under the test conditions detonation velocity was dependent upon explosive confinement and fracture-propping sand. The detonation velocity of a confined nitroglycerin explosion in aluminum tubes can be reduced by as much as 85 percent, when the tube contains fracture-propping sand. The shape of the reservoir, whether triangular or rectangular, has little effect on the detonation velocity or explosive propagation. The critical or minimum explosive-layer thickness between glass plates, capable of supporting propagation, was 0.0312 in. The presence of a fracture-propping sand in the sheetlike layers increased the critical explosive layer thickness to 0.0625 in. In nitroglycerin-filled and nitroglycerin-sand filled tubes, the minimum tube diameters successfully tested were 0.125 in and 0.375 in, respectively.

Jan 1, 1969

By Thomas W. Camm

The U.S. Bureau of Mines has developed a system for estimating mining and processing costs as a function of process feed rate with the objective of applying this system to abandoned mine tailings and to evaluate the benefits, if any, of metal recovery. Cost analysis was applied to the mine wastes of Smelterville Flats: an extensive area of mine tailings in the Bunker Hill Superfund Site with high concentrations of lead, zinc, and other sulfide minerals. Results from previous site characterization and metallurgical processing studies were used as the input for the cost analysis. This analysis indicated that processing this site at an optimum production rate of 3,500 short tons per day (st/d) could generate a positive cash flow.

Jan 1, 1993

By Frank B. Fulkerson

A study was made of scrap iron and steel in the South Central States in order to determine trends in processing, shipment, and consumption if this important commodity. These data were derived in part from statistical sources and in part by visits to scrap yards and steel mills. Trends in the industry were reviewed. Dealers in 1963 supplied 1.8 million tons of iron and steel scrap to steel mills and foundries in the south-central area, compared with 2.1 mill ion tons in 1955. Most of the scrap was processed and shipped within 200 to 300 miles of consuming centers. Exports provide a principal outlet for dealers along the gulf coast. Most of the scrap that fills these orders is loaded onto freight cars at yards in Texas and Louisiana and is shipped to ports for direct transfer from railroad car to ship. The tonnage exported varies greatly from year to year. The largest scrap operations are in or near large cities which are heavy scrap generating areas, steel mill sites, or port cities for export of scrap. A tentative analysis indicates that the short-run supply of prepared scrap is inelastic to price changes; therefore, buyers probably are in a strong bargaining position at times of declining demand. One technological development in the iron and steel scrap industry is the use of large presses which can take complete automobiles with frames, wheels, springs, and other heavy parts still intact and reduce them to bundles. At Houston, Tex., and Kansas City, Mo., shredding plants are in operation that reduce car bodies and other light scrap into flat pieces 4 to 6 inches in size.

Jan 1, 1966

Consumption and intensity of use trends for twelve metals, by industrial end use, were estimated for 1972 through 198Z. The trends were then forecast through 1993 using standard statistical methods. The intensity of use measure selected is the quantity of metal consumed per constant dollar output of a specific industrial sector. The metals studied were aluminum, chromium, cobalt, copper, lead, manganese, nickel, the platinum-group metals, tin, titanium, tungsten, and zinc. Average annual growth rates for the following four of the twelve metal increased from 1972-82 as follows: aluminum, 1.00 percent; platinum-group metals (consisting of platinum, palladium, and iridium), 8.83 percent; titanium, 7.82 percent; and tungsten, 6.09 percent. Consumption. for the remaining eight metals decreased at average annual rates ranging from 0.58 percent (copper) to 5.37 percent (manganese).

Jan 1, 1986

By D. E. Larson

The U.S. Bureau of Mines investigated Fe-base alloys containing 8 pet Crwith Ni, AI, and Si additions as substitutes for standard AISI Type 304 stainless steel (SS) in high-temperature oxidizing applications. The objective of this study was to reduce the amount of Cr required to make an austenitic stainless steel while retaining satisfactory workability, mechanical properties, and oxidation resistance. Alloys prepared in this investigation had a composition of Fe-8Cr-lMn-0.07C with varying amounts of Ni, AI, and Si. A minimum of 10 pet Ni was required to achieve an austenitic composition. The microstructures of the austenitic alloys were very susceptible to room-temperature, deformation-induced martensitic transformations. When the alloys were cold worked or stressed, the materials had far greater tensile strengths than Type 304 SS at room temperature. At higher temperatures, tensile strengths and workability of several of the alloys were comparable to that of Type 304 SS. Although martensitic transformation caused the room-temperature properties of the experimental alloys to be quite different than those of Type 304 SS, the superior oxidation resistance and similar hot workability of several alloys encourage their use as replacements for Type 304 SS.

Jan 1, 1989

By S. M. Shelton

Tests employing various ore-dressing methods were made on a manganese wad ore from the W. A. Chinn property in the Batesville-Cushman district of Arkansas in an effort to develop a practicable procedure for the production of ferromanganese-grade concentrates. The ore body occurs as a bed approximately 7 feet thick in the residual clay of the Ferndale limestone formation5/. The crude wad ores are soft aggregates of various oxides of manganese, which are loosely bonded together. Hard lumps of high-grade ore are disseminated throughout the wad. Hausmannite, pyrolusite, and psilomelane are the principal minerals. Some clay is present, but most of the gangue consists of leached fragments of the original siliceous and calcareous rocks in which the manganese occurred. In addition, hydrated oxides of iron, which axe present, also must be considered as gangue. Definite phosphate minerals have not been identified.

Jan 1, 1942

By Eleanor Abshire

[THE INCREASING use of hafnium as a vital component in atomic power reactors has brought this metal into recent prominence. A literature survey was made and this bibliography was compiled to provide research and production groups with a ready source of reference to this important metal anti its compounds. This service is rendered by the Zirconium Information Center, which is sponsored by the Department of the Navy, Bureau of Ships, and the F .S. Department of the Interior, Bureau of Mines, tit the Bureau's Northwest Electrodevelopment Experiment Station, Albany, Oreg. The following reference sources have been reviewed for this compilation : Chemical Abstracts; Industrial Arts Index; Crerar Metals Abstracts; Nuclear Sciences Abstracts; Bureau of Mine; Information Cicular 7771, Bibliography of Zirconium; anal Bureau of Mint' Information Circular 7830, Bibliography of Zirconium, suppllement to Information Circular 7771.]

Jan 1, 1960

By C. B. Kenahan

The Bureau of Mines is developing methods for reclaiming the metal and mineral values contained in municipal incinerator residues. This report describes the first phase of the research, in which reliable methods for sampling and analyzing municipal residues were established and the composition and characteristics of the residues were determined. Samples were obtained from a variety of grate-type furnaces and also from a rotary kiln furnace. The samples were processed on a batch basis and separated into their natural categories by a variety of methods including screening, magnetic separation, air separation techniques, and handpicking. The main components of the residues were determined to be metal and metal oxides, glass, and ash.

Jan 1, 1968

By John R. Bartels

This Bureau of Mines report describes the development of a preliminary design for a novel, protected, cab-shuttle car for use in working seam heights down to 40 in. Because of the severe restrictions imposed by low-coal operation, Mine Safety and Health Administration (MSHA) regulations only require canopy protection on shuttle cars operating in seam heights of 42 in or greater. MSHA routinely grants variances for canopy use in seams 48 in high or less. The design was generated by giving the operator needs equal priority as related to machine performance parameters. Cab-shuttle car concepts that led to the recommended design are described, along with criteria and testing used to evaluate their potential effectiveness.

Jan 1, 1988

By Pablo Velasco

The Belize economy recorded modest growth during 1980; the growth of the gross domestic product (GDP) in real terms was between 1% and 2%. At current prices, the 1980 GDP reached $108 million2. This output was largely attributed to the performance of a few industries, mostly nonminerals. Such performance improved significantly the balance of payments situation by reducing the deficit from $19 million in 1979 to $4 million in 1980. The rate of inflation was an estimated 18% in 1980 and would have been greater if not for a conservative monetary policy and price control on a number of essential items. Expert earnings increased $43 million, or 50%, from the 1979 level. After increasing more than 25% in 1979, imports increased only 6% in 1980 to a level of $141 million owing to the decline in investment and stabilization of petroleum prices. The balance of trade deficit was $9.8 million in 1980, a marked improvement from the 1979 level of $45.1 million. The mineral output for Belize accounted for only a fraction of 1% of the GDP. Such activity was limited to the production of limestone, marl, and sand and gravel, all of which were primarily used in construction of the Northern Highway between Orangewalk and Belize City. Mineral resources are deficient or nonexistent in Belize for the majority of metals and nonmetals, although the Government and others continue to believe that petroleum must exist in Belize. The proximity to Mexican oilfields and the growing finds in the Peters area of Guatemala support this expectation. The Government continues encouraging exploration onshore and offshore and offers terms that

Jan 1, 1982

By Robert Torbin

The objectives of the Continuous Shaft Lining (CSL) System are to reduce the costs, safety hazards, and time currently required in lining mine shafts with concrete. The CSL will line machine bored shafts downward from the shaft collar on a continuous basis using an inverted, pressurized slipforming technique. The technique for slip-forming downwards has been demonstrated and refined under this program. The approach taken involved laboratory scale testing of key features of the CSL concept. These feature tests included concrete distribution, concrete sealing, concrete slipforming and development of a reliable concrete mix. Based on these results, a full scale above-ground test facility and CSL were designed and fabricated. The objectives of these tests were to demonstrate the viability of the basic concept; to establish operating limits; and to provide input data and information for the design of a second generation shaft lining system. The results of the program have led to a CSL design and operational philosophy which will need to be tested in an underground environment before industry will accept the technology. However, the next generation CSL promises to meet all the original program technical objectives.

Jan 1, 1983

By G. G. Campbell

The Bureau of Mines initiated a field test of underground coal gasitication to investigate the technologic feasibility of gasifying a subbituminous coal. The test site is near the town of Hanna, Wyo., about 70 miles northwest of Laramie. Preliminary results of the experiment are described. The coal was ignited in the central well of a 16-well pattern. Both forward and reverse combustion techniques were attempted to prepare a path of sufficient permeability to permit the high air injection rat s necessary for gasification. Gasification between linked wellbores was sustained for periods as long as 3 months. Hydrogen-rich gas having a heating value of 100 to 150 Btu/scf was produced.

Jan 1, 1974

By V. F. Parry

The object of this report is to present certain pertinent data on the physical and chemical properties of South Arcot lignite and to present the results of several special tests to show how the raw lignite can be upgraded to superior fuels for certain special uses. The Bureau of Mines Branch of Coal Technology laboratories at Denver have advocated the drying and carbonization of all low-rank fuels for special uses and have introduced and developed new techniques for upgrading and refining noncoking coals. Application of these techniques to the South Arcot lignites was the object of the investigation, and this report presents significant data necessary for planning a fuel program based on utilization of dried and carbonized dusts. In general, the South Arcot lignite is similar in chemical properties to the high-moisture lignites found in the United States and has some physical properties similar to Australian brown coals. The samples submitted for test had lost moisture before delivery to the laboratory, and it has been necessary to estimate the analysis of the lignite in place in the mine. Various observations made in India by qualified technicians indicate that the bed moisture content of the entire seam is in the range of 54 to 56 percent. For estimating purposes in this report, the bed moisture content has been taken as 56 percent and the ash content of the fresh coal as 2.5 percent. The average analysis estimated for the as-mined lignite is: [Moisture percent 56.0 Volatile matter do.22.0 Fixed carbon do.19.5 Ash do.2.5 Heating value B.t.u. per lb. 4,890]

Jan 1, 1957

By Elbridge W. Gresseth

Rock deformational structures in a deep mine were analyzed by petrofabric techniques to learn (1) the relative magnitude and direction of the principal stresses involved in tectonic deformations prior to mining, (2) the preferred orientation of rock planar discontinuities which define rock anistropy prior to mining, and (3) the relationship of mining-induced rock failure to inherent rock stresses and inherent rock anisotropy. Rock fabric elements used for petrofabric analysis consisted of bedding planes, faults, joints, fractures, foliation, sericite plane (001), quartz axis [0001], quartz deformation lamellae, and microfractures. Structures and structural symmetries from different areas within the mine and from different scales of observation were compared to learn the nature of rock anisotropy and the orientation of the principal stresses defined by rock deformations. Analysis of such fabric as regional and macroscopic faults, b-c joints, quartz [0001], sericite (001), and microfractures, indicate that during the epochs of tectonic deformation, the maximum and minimum principal stresses were horizontally oriented and acted along northwest and northeast axes, respectively. This condition of regional stress appears to have continued during folding and the associated period of faulting. The most recent tectonic deformation represents a rotation of the minimum principal stresses into a vertical position, as shown by the development of a tensile joint system, quartz deformation lamellae, and microfractures. Good interscale correlation and statistical homogeneity of tectonic fabric indicate a stress field homogeneity in this area during tectonic deformation. Rock physical anisotropy is genetically associated with tectonic fabric and consists of preferentially oriented planar discontinuities intersecting along a nearly vertical axis. The mining-induced deformations were correlated with the inherent rock anisotropy which either directly controls or greatly affects their development. This phase of rock deformation shows a greater degree of stress field heterogeneity than was the case with tectonic deformations This is explained as a result of nonconfinement afforded by underground openings and the increase in ground stresses due to mining activity"

Jan 1, 1968

By S. J. Davenport

The increased consumption and importation of fluorspar and cryolite (1)3/ in recent years, and especially the addition of fluorine compounds to drinking water in the United States, have aroused renewed interest in the properties of such compounds and possible health hazards incident to their use. It has been suggested that the issuance of a revision and elaboration of Information Circular 7311, The Hazards of Hydrogen Fluoride Poisoning in the Mineral and Allied Industries, which hay been out of print for some time, would be opportune. Fluorine minerals have been known since the Middle Ages. Fluorine was isolated in 1886 by Moisson (2).

Jan 1, 1954

By James A. Brierley

Wastewater from uranium mines in the Ambrosia Lake district near. Grants, New Mexico, U.S.A., contains uranium, selenium, radium, and molybdenum. The Kerr-McGee Corporation has a novel treatment process for waters from two mines, sections 35 and 36, to reduce the concentrations of the trace contaminants. Particulates are settled by ponding, and the waters are passed through an ion exchange resin to remove uranium; barium chloride is added to precipitate sulfate and radium from the mine waters. The mine waters are subsequently passed through three consecutive algae ponds prior to discharge. Water, sediment and biological samples were collected over a 4-year period and analyzed to assess the role of biological agents in removal of inorganic trace contaminants from the mine waters.

Jan 1, 1981

By Edward W. Parsons

The explosive-anchored rockbolt was field tested in six mines where rock conditions varied from incompetent shale or mudstone through fairly soft sand-stone to firm sandy shales. The purpose of the testing was to document, under a wide variety of conditions and in comparison to other rockbolt anchors, the quality of the anchorage produced by the explosive-anchored bolt. In addition, the length, strength, and design of the explosive charge necessary to produce positive anchorage up to the yield strength of the weakest component of the bolt were determined. A l4-inch length beaded explosive charge was found to be suitable, in general, in relatively weak strata, and the length can be reduced in more competent strata. Of the 127 explosive?-anchored bolts tested, 118 bolts produced an evaluated anchorage in excess of 17,000 pounds. Only 4 of 43 expansion-shell bolts and 4 of 14 wedge bolts produced anchorage this good. In preliminary tests, properly coupled explosive-anchored bolts did not ignite an explosive gas mixture. Some minor phases included in the investigation were as follows: (1) effect of explosive-anchored rockbolt on surrounding rock; (2) effect of time on anchored bolts based on torque tests; (3) effect of submersion in water on rockbolt anchorage; (4) pull tests to higher loads; and (5) ignition tests.

Jan 1, 1965

By Nicholas R. Dixon

This report summarizes all work performed under Phases I, II and III of U.S. Bureau of Mines Contract H0387006, "Development of a Prototype Retrofit Noise Control Treatment for Jumbo Drills." The noise and vibration levels of four jumbo drills were characterized and a survey of percussive rock drill usage is reported. A Gardner-Denver DH 123 drill was chosen as a demonstration drill, and extensive noise diagnostic studies were performed. Noise control treatments were designed, developed and evaluated in a reverberant drill test facility. The treatments consisted of an integral enclosure/muffler for the drifter, vibration isolation of the drifter from the enclosure and feed, and a drill steel sheath. A 19 dBA reduction in overall sound power level was achieved with no loss in drilling rate. The prototype retrofit treatments were field tested in an aboveground mine and in a production section of an underground zinc mine. Long-term durability and operator acceptance of the enclosure/muffler treatment were excellent. Preliminary evaluation of the drill steel sheath was encouraging, although additional testing is required.

Jan 1, 1982

By W. M. Deaton

[The formation of gas hydrates in natural-gas pipe lines depends on temperature and pressure conditions in the lines as well as on the presence of condensed water. The operating pressure in a pipe line may be determined easily and usually is available from the records of operation, but the temperature seldom is known. In cooperation with the American Gas Association, the Bureau of Mines, in its investigation of gas hydrates, conducted a pipe-line-temperature survey and studied underground temperatures at depths at which pipe lines ordinarily are buried and the relationship of these temperatures to prevailing atmospheric conditions. A similar but more limited study of this type was, conducted by engineers of the Bureau of Mines a number of years ago.4/A summary of the earlier findings was included in a general report by the Bureau on the flow of natural gas through high-pressure transmission lines.5/ In the present study, data on temperature variations were obtained at several places widely separated geographically. This information should assist pipe-line engineers in designing and operating natural-gas pipe lines. In the pipe-line-temperature survey here resorted, a study was made along a 22-inch natural-gas pipe line: originating near Amarillo, Tex., and extending northwestward through New Mexico into Colorado (fig. 1). Some data also were collected along a 16-inch line extending southward from Amarillo. In the study of underground temperatures and their variation with atmospheric temperature, recording; equipment was installed at the]

Jan 1, 1941

By Joseph Grumer

Theory pertaining to the exchangeability of fuel gases on appliances has been extended to exchanges of propane or butane with mixtures of these. In particular, new considerations were developed bearing on the hazard of an occasional emission of carbon monoxide and flashback and blowoff possibilities. The new considerations involve using current requirements for approval of liquefied petroleum gas appliances. These requirements were used to predict allowable tolerances in chemical composition of liquefied petroleum gases for existing appliances. In addition, changes in gasline pressure were computed which may be substituted in place of fuel exchanges during testing of appliances,

Jan 1, 1962