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By Joseph A. Perry

One goal of the Bureau of Mines is to develop technology tp insure a dependable supply of minerals to the United States. To support this goal, the Bureau's Albany Research Center has modified a commercial atomic absorption spectrophotometer to rapidly determine trace levels of mercury by cold-vapor atomic absorption spectrophotometry. Such diverse materials as ores, mill products, stream water, sediments, and flue dust have been analyzed. A very high dynamic range of 0.2 ng/ml to 1 µg/ml of mercury in solutions is routinely analyzed by this instrument.

Jan 1, 1981

By Barry W. Klein

The performance of the U.S. economy in 1977 was similar to that in 1976 which, in turn, had been a considerable improvement over 1974-75. In 1977 real gross national product (GNP) showed a similar, but some-what slower, growth pattern compared with 1976. Real GNP increased sharply in the first quarter of the year followed by smaller increases for the remaining three quarters. With only two exceptions, the monthly unemployment rate declined or remained steady throughout 1977, falling to a low for the year in December. The inflation rate in 1977 was slightly higher than in 1976, but the rate still remained far below that of 1974-75. Total U.S. output as measured by GNP in current dollars rose 10.8% in 1977. Real GNP in constant 1972 dollars increased 4.9%, and inflation, as measured by the implicit price deflator, rose 5.6%. In real terms, gross private domestic investment for residential structures increased 19.3% in 1977, only slightly below the 22.9% rise in 1976; State and local government expenditures increased 1.1 % in 1977; and personal consumption expenditures for services rose 4.5%.

Jan 1, 1980

By R. H. Sprute

Extensive Bureau of Mines laboratory testing has shown that electrokinetic densification can be an effective method for dewatering and consolidating unclassified metal mine mill tailings. The report describes results of a limited field test of this technique. Eighteen-cubic-yard concrete model stopes, 18 feet long by 6 feet deep by 56 inches wide, were filled with unclassified tailings slurry from a metal mine in the Coeur d'Alene, Idaho, district. Five different tests were performed. They showed that a strong, dense, dewatered fill can be obtained in a reasonably short time using electrokinetics, with typical power consumption of 25 to 30 kW-hr/yd3 of densified fill. At present power costs in the Coeur d 'Alene district, this would amount to 10 to 12 cents/yd3.

Jan 1, 1975

By W. C. Hudson

"The McLeod sand pits, on the northeast side of the Little Ocmulgee River in Wheeler County, Ga., opposite Lumber City in Telfair Co., were examined by the Bureau of Mines under its war program of Investigation of Critical and Essential Minerals. The pits are about a quarter of a mile above the bridge, which is half a mile above Lumber City. Mrs. A. T. McLeod of Lumber City owns the land, including the pits. The property was inspected by an engineer of the Bureau of nines on March 8, 1945, on recommendation of Capt. Garland Peyton, director, Division of nines, Mining, and Geology of Georgia.The Mcleod pits are at the northwestern extremity of a mile-long series of old pits that were worked from about 1900 until the 1920's. The burning of the spur railroad bridge connecting the pits with the Southern Railway at Lumber City stopped mining operations. The pits on the south-east, or opposite, side of the Glennwood Road from the McLeod pits were first worked by F. L. Hinson and later, in 1921, by Mrs. n. H. Mobley. The glass sand was shipped to Tallapoosa, Ga., and Chattanooga, Tenn., where it was used in the manufacture of bottles for soft drinks. Some of the sand was used as molding and construction material. The sand was mined by hand shoveling it into wheelbarrows, which were unloaded on freight cars. The pits were partly refilled with overburden, so that it is impossible to estimate even roughly the amount of sand excavated.Analyses of samples of glass sand made years age3/ and later in 19404/ roughly check those made by the Bureau of Mines laboratory, except that in the former the iron oxide content usually was greater, attaining a maximum of 0.72 percent.The sand pits are in a valley slightly more than a quarter of a mile wide that lies along the northeast side of the Little Ocmulgee River. The land is either flat or marked by ridges only a few feet high. . A rather thick growth of scrub trees covers most of the valley. The surrounding country consists of gently rolling farm lands. The altitude of the valley is not known, but, judging by its distance from the seashore, it probably is about 200 feet. In addition to the Glennwood highway, which crosses the valley, several old sand roads lead to the pits."

Apr 1, 1946

To suppress the natural bacterial action in acid mine drainage (AMD), the major contributor to acid formation. Approach Recycle partially-treated affluent back to the source of AMD within a mine, or to the coal or coal-waste stockpile. This effectively eliminates any further biologically-promoted AMD by inhibiting catalyzed weathering or oxidation by acid-forming bacteria. How it Works AMO-type effluents can be largely reduced by "recycling" the acidic outflow back to the source of AMD within a mine or to the Input side of a waste pile to percolate through the reactive pyrite and bacteria mixture. The bacteria in the cell thrive on the oxidation of ferrous to ferric iron through the electron transfer, Fe2 +[=]Fe3 + + e. Its reaction product [s, therefore, essentially ferric iron. While small quantities of Fe3 + will not interfere with the exponential multiplication of the bacteria

Jan 1, 1982

By D. S. Kimmel

The Bureau of Mines sponsored development of a system to remotely energize and de-energize the trolley wire in a section in response to demands from vehicles as they enter and leave the controlled section. The system developed utilizes a detector/actuator that controls a dc contactor at the outby end, and a 3 kHz oscillator at the inby end. A prototype system has been built and installed at the Bureau's trolley test site at Bruceton, Pennsylvania which has demonstrated the ability to also provide load discrimination for faults of 300 amperes or more. The system could readily be modified by locating the oscillator on the vehicle to provide automatic de-energizing of the trolley wire when the vehicle's pole is removed or the vehicle leaves the section.

Jan 1, 1978

Mainland China To Pay Japanese Company On Contract Claim. - Mitsubishi will receive $39 million from Red China, half of what was asked, for China's having, curtailed work on a 5369 million steel rolling mill at Baoshan near Shanghai. Copper Found in Chile. - Utah International Inc., in conjunction with Getty Oil Co., has discovered a cooper deposit in northern Chile. Early drilling reveals an enriched zone grading 1.2% to 2 3% copper. Chile already has tie world's largest Cu reserve base. Soviets To Aid Laotian Tin Industry. - The U.S.S.R. has agreed to help strengthen the tin industry in Laos, a client state. In the past, Laos has only produced small amounts of tin concentrate, 500 tons to 1,000 tons per year presumably shipped to smelters in Singapore or Penang, Malaysia. Under the agreement made in June, the Soviets are to supply equipment to increase the out put of tin from the Phontieu, Neng, and Nongsen mines and help Laos with the construction of a tin smelter. The U.S.S.R. itself is a net importer of tin, although a substantial producer of the metal.

Jan 1, 1981

By Lloyd A. Morley, Robert Stefanko

Before going directly to the analysis, it would be good to summar¬ize explosion-proof container approval methods. Both Magison (52) and Short (84) state that in general practice, the systems are certified for: 1. a rugged enclosure able to withstand an internal explosion but not allow explosively hot gases to escape, and 2. maximum surface temperature, with equipment operating inside, that will not ignite the surrounding atmosphere. Also, testing insures that any material in contact with the container surface will not be ignited by a hot spot. Associated with the first practice, the enclosures are inspected for: 1. a safe flange gap width, 2. a pressure increase during ignition, and 3. an hydrostatic pressure withstand level. The hydrostatic pressure level is almost always determined by a meas¬ured ignition-pressure test and is usually applied to prove the mechan¬ical design to some safety factor. Consequently, explosion-proof enclosure testing includes temper¬ature, permissible flame gap, and pressure. Specifications and prev¬ious research also can be similarly separated even though some interre¬lation exists between the flame gap size and internal enclosure pressure during an explosion. The Schedule 2G Sections applicable to these subjects are: 1. 18.2 Definitions; 2. 18.6 Applications;

Jan 1, 1974

By R. Craig Smith

The Bureau of Mines conducted a study of production costs for the secondary lead industry and determined costs for present, pending, and proposed environmental legislation. Operating costs for smelters by capacity groups range from 16.8 to 19.6 ¢!lb of refined lead. Present regulatory compliance costs for these groups range from 2.2 to 2.4 ¢!lb. Pending compliance costs could add 3.5 ¢!lb of refined lead, and proposed regulations could add another 1.3 ¢!lb. The individual capital costs necessary to comply with pending environmental regulations are estimated to be $1.8 million for small smelters and $10.4 million for large smelters. Proposed regulations could require additional expenditures from $1.9 million for small smelters to $4.9 million for large smelters. These cost estimates, based on average 1985 dollars, indicate that pending and proposed legislation could add significantly to capital and operating costs of the secondary lead industry. These regulatory compliance costs may result in a loss of up to 40 pet of secondary lead production capacity.

Jan 1, 1987

By L. W. Brandt

Studies of liquid-vapor equilibria of gas mixtures at the Bureau of Mines Amarillo Helium Plant Laboratory require that the equilibrium cell be maintained uniformly at any desired temperature from approximately room temperature to -320° F. The temperature-control system must also tolerate a substantial heat input, in the form of warm gas flowing into the cell, without loss of control. Temperatures between the sublimation temperature of carbon dioxide (-109° F.) and the boiling point of liquid nitrogen (320° F.) are usually obtained by methods utilizing a hydrocarbon liquid bath cooled by liquid nitrogen.4/5/6/7/ Owing to the fire hazard attending such baths, a safer method of temperature control was desirable.

Jan 1, 1955

By Owen W. Terry

During the summer of 1943 the Bureau of Mines conducted an investigation and program of churn drilling on the McIlhon and adjoining Pearson land in the Mineral Point district of Iowa County, Wis. Sixteen holes, aggregating 1,570 feet .of bore, were completed. The work was undertaken as part of a general investigation of the zinc-and lead-producing area of southwestern Wisconsin at a time when great effort was being made to increase the production of Metals important to the war program. The Bureau's drilling program supplemented a previous drilling pro-gram conducted by the Vinegar Hill Zinc Co., and demonstrated the presence of a strongly mineralized zone at relatively shallow depths.

Jan 1, 1948

By D. J. Parker

Owing to its flexibility, convenience, economy, ands availability, electric power is peculiarly adapted to the needs of the coal -mining industry. Because of such obvious advantages, the application of electricity has in recent years become more and more extensive and is now a most important factor in the Nation's coal prediction. With the introduction of this type of power into coal mines certain new, specific, and well-recognized hazards resulted. The question arises, therefore: Has the industry met these hazards squarely and. effectively? With respect to some individual companies, the answer happily is in the affirmative; with respect to the industry as a whole, there is much room for improvement.

Jan 1, 1933

By William J. Campbell

The Federal Bureau of Mines provided five test materials--amosite, short-and long-fiber chrysotile, crocidolite, and nonfibrous tremolite--to the National Institute of Environmental Health Sciences (NIEHS) for studies on the biological effects of orally ingested asbestos-related materials. An inter-agency agreement between the Bureau and NIEHS made possible this program to characterize these test materials. The Bureau in turn received support through contracts with the Ontario Research Foundation for the milling of amosite and crocidolite, and with the University of Maryland for microscopic measurements. The five test materials, which were supplied in quantities of 960 to 1,200 pounds each, were characterized by chemical-instrumental analysis for elemental composition, surface area, density, X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, mineralogy, and particle size analyses. Particle size distributions were emphasized because of the current theories relating adverse biological effects to length-width characteristics of durable elongated particles.

Jan 1, 1980

By William C. Larson

This Bureau of Mines report discusses uranium in situ leach mining in the United States to acquaint the public with an overview of this emerging mining technology. This report is not intended to be a technical discussion of the subject matter, but rather should be used as a reference source for information on in situ leaching. A list of in situ leaching publications is included as well as engineering data tables for almost all of the active pilot-scale and commercial uranium in situ leaching operators. These tables represent a first attempt at consolidating operational data in one source, on a regional basis. Additional information is given that discusses the current Bureau of Mines uranium in situ leaching research program. Also included is a listing of various State and Federal permitting agencies, and a summary of the current uranium in situ leaching operators. Finally, a glossary of terms has been added, listing some of the more common terms used in uranium in situ leach mining.

Jan 1, 1978

By M. Kanda, J. W. Adams

A system for measuring amplitude probability distributions (APD’s) of electromagnetic noise in coal mines is described and typical APD’s from an underground coal mine are presented. The APD is a basic statistic required for the design and analysis of communication systems, especially those intended for use in noisy environments, and where neither overdesign nor underdesign is acceptable. The rms and average field strengths are obtained by integration of the APD, and examples are shown at several frequencies. All field strength levels are given in absolute units. Selected frequencies cover the range from 10 kHz to 32 MHz.

Jan 1, 1973

By d&apos, Kathleen J. Amico

THIS SUAMMARY is shown in Minerals Yearbook volumes I and III of this series on mineral production in the United States, its island possessions, the Canal Zone, and the Commonwealth of Puerto Rico, and on the principal minerals imported into and ex- ported from the United States. The several commodity and area chapters contain further details on production. A summary table comparing world and U.S. mineral production also is included. Mineral production may be measured at any of several stages of extraction and processing. The stage of measurement used in the chapter is normally what is termed "mine output." It usually refers to minerals in the form in which they are first extracted from the ground, but customarily includes for some minerals the product of auxiliary processing operations at or near mines.

Jan 1, 1962

By T. E. Purcell

(a) Moisture. - Moisture, "as fired," is specifically significant in pulverized-coal firing because of its effect upon the continuity of raw-coal feed to the pulverizer, pulverizer capacity, flame stability, and speed of ignition. The extraneous moisture content is a rough index of potential difficulties in unloading and maintaining the flow of raw coal to the pulverizer and of pulverized coal to the furnace, with the troubles increasing geometrically as the percentage increases. Sticking or other stoppage of coal flow at any point between the bunker and the furnace is especially serious with pulverized-coal firing because there is danger of immediate loss of output. Where moisture is a problem, the designer must exercise great care in the design of coal-handling and preparation apparatus.

Jan 1, 1951

By T. O. Llewellyn

The Bureau of Mines investigated the use of a heavy liquid in combination with fluid cyclones to separate brucite from a Nevada ore on a continuous basis, using a mixture of dibromomethane and trichloroethylene having a density of 2.44 grams per cubic centimeter. Single-stage cyclone separation produced a concentrate that contained 84 percent of the total magnesia at a grade, on a calcined basis, of 95.6 percent MgO.

Jan 1, 1974

By L. A. Neumeier

The Bureau of Mines evaluated the properties and anisotropy in properties of rolled Zn-Ti and Zn-1.0 wt pct Cu-Ti alloys containing up to 0.36 wt pct Ti. Finish rolling was at varied temperatures to total reductions as high as 92 pct. Alloy properties are very sensitive to various combinations of composition, rolling temperature, and reduction. Properly rolled Zn-1.0 Cu-Ti alloys are superior in strength to Zn-Ti alloys. Conditions are described that lead to best tensile properties. Creep resistance for Zn-Ti alloys decreases with increased rolling temperature when finish rolled to 92-pct total reduction: but not when finish rolled to 33- or 67-pct reduction. Creep resistance for 7n-1.0 Cu-Ti alloys improves with increased rolling temperature to about 480° F. Heavily cold-rolled Zn-1.0 Cu-Ti alloys have fine grain sizes and poor hardness, tensile, and creep properties, but high ductility. Thermal expansivity is markedly affected by the copper addition. Data show the anisotropy of tensile, creep, and thermal expansivity properties. Large idiomorphic crystallites of TiZn15 appear in both Zn-Ti and Zn-Cu-Ti alloys when more than about 0.2 pct Ti is present. A new Zn-Cu-Ti intermediate phase was also identified. Empirical equations are presented relating creep rates with major process variables.

Jan 1, 1971

By Ronald F. Balazik

The introduction of "high-tech" materials such as new polymer composites presents significant competitive challenges and opportunities in conventional mineral markets. Moreover, rapid advances in materials science are critical to the resolution of important economic and strategic issues, including national competitiveness and import dependence. This Bureau of Mines study examines the displacement of conventional nonfuel mineral materials by certain new materials, specifically advanced plastics and ceramics. Analyses of substitution by plastics are conducted for five major U.S. industrial sectors: motor vehicle manufacturing, aerospace applications, building and construction, packaging, and heavy machinery production. Based on interviews with more than 60 scientists, executives, and other professionals engaged in materials development and sales, forecasts of substitution by plastics during the 1990's are made for aluminum, steel, and glass. In addition to these forecasts, study findings identify key factors that will influence the emergence of advanced materials in the next decade.

Jan 1, 1987