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By T. A. Sullivan

Research undertaken by the Bureau of Mines in 1938 has resulted in the development of titanium from a laboratory curiosity to a commercial metal. Along with processes for producing the metal, it was necessary for the Bureau to develop methods for analyzing the metal, raw materials, and intermediate products. Some of the methods developed have been published.3 4 5/ General Services Administration (GSA) was responsible for purchasing titanium metal under Defense Production Act contracts with commercial producers. GSA designated the Federal Bureau of Mines to analyze this metal and establish its compliance with Government specifications. A substantial quantity of tin was found in some of the samples analyzed, and in July 1957 tin was added to the list of impurity elements to be determined. The specifications limited the amount of tin in titanium sponge to a maximum of 0.10 percent. A program was immediately initiated to investigate methods and techniques for determining tin in the range of 0 to 1.0 percent. A method accurate at the 0.10 percent level was necessary, as this level was the critical range for acceptance or rejection of the metal.

Jan 1, 1960

By W. H. Eddy

The Bureau of Mines conducted laboratory batch-and small-scale continuous flotation processing tests on waste granite fines from Georgia, to determine the feasibility of recovering usable feldspar and quartz products by flotation. Two flotation methods were utilized for the removal of biotite and other iron-bearing minerals: One was in an acid-cationic circuit, and the other in an alkaline-anionic-cationic circuit. Feldspar was recovered using an acid-cationic method. To produce commercial-grade feldspar and quartz products it was necessary to employ either two sequential froth flotation circuits or one froth flotation circuit supplemented by wet-magnetic separation techniques to remove iron contaminants. Continuous flotation processing yielded a commercial-grade feldspar concentrate containing, in percent, 3.8 Na20, 5.4 K20, and 1.10 CaO, with recoveries of 77.8, 70.3, and 64.4, respectively. The feldspar tailing was high-quality glass sand containing 98.2 percent SiO2 and 0.024 percent Fe2O3. About 42 percent of the quartz was recovered at glass sand specifications. An effective separation of, potash feldspar from the bulk feldspar concentrate was achieved by batch flotation in a mineral separation cell.

Jan 1, 1974

By E. D. Eastman

The recent determination by Eckman and Rossini of the heat of formation of sulphur dioxide appears to be of much greater accuracy than any previous measurement . The value obtained by them , 70,940 cal . , is in good agreement with that of Thomsen ( 71,080 ) , but differs by about 1,700 calories from Berthelot's result ( 69,260 ) , and by 1,940 calories from the provisional figure ( 69,000 ) adopted by Lewis and Randall in their studies of the free energies of the sulphur compounds . This large discrepancy suggested the desirability of a recalculation of the free energy of sulphur dioxide . In addition it is now possiblt to fix the specific heat of S₂ gas with greater certainty than at the time of the original calculations . These two changes are incorporated in the recalculations described below , and directly affect the values of AH , and the Ar terms in the free energy equation . In the determination of the integration constant of the latter equation , the free energies and specific heats of water vapor and the oxides of carbon are required as auxiliary data . In this work these are based , with certain exceptions , upon the equations previously deduced , which differ appreciably from the corresponding equations of Lewis and Randall . 56 · The principal equilibria employed below , and the plan of calculation , remain the same as in the calculations of Lewis and Randall . Before beginning this revision a search of the literature was made , extending to August , 1930 , for studies of additional equilibria . Only one reaction was found that gives promise of increased accuracy . This is the equilibrium of sulphur dioxide with copper , cuprous oxide , and cuprous sulphide . In this case , however , certain of the subsidiary data are lacking , and until they become available , the existing studies of the equilibrium in this system can not be successfully utilized . The changes in the numerical data mentioned above , especially in the thermochemical constants , are therefore solely responsible for the rather significant differences of the revised from the original values of the free energy .

Apr 1, 1931

By David C. Byrne

PURPOSE: Evaluate practical technological advances in hearing protective devices for use in different mining environments. RESEARCH SUMMARY: Previous NIOSH research shows that miners develop hearing loss much more quickly than nonoccupationally noise-exposed individuals. Also, miners experience a greater severity of hearing loss than would be expected for nonoccupational noise-exposed persons of the same age and sex. As described in the National Occupational Research Agenda, problems created by occupational hearing loss include (1) the reduced quality of life due to social isolation and unrelenting tinnitus, (2) impaired communication with family members, the public, and coworkers,(3) a diminished ability to monitor the work environment (e.g., warning signals, equipment sounds, etc.), (4) lost productivity and increased accidents resulting from impaired communication and isolation, and (5) expenses for workers’ compensation and hearing aids. Although the elimination of hazardous noise is the ideal long-term solution to the noise problem, miners will likely need to rely on personal hearing protection in certain situations for quite some time. However, it is well known that noise attenuation provided by hearing protectors as they are worn during everyday use in the workplace is usually worse than when tested under laboratory conditions. Additionally, workers may refuse to wear their hearing protection for any number of reasons. Therefore, this project was initiated to evaluate practical technological advances in hearing protectors, with an emphasis toward optimizing the balance between effectiveness, comfort, overprotection, and communication ability. Currently, the necessary in-house laboratory facilities and research techniques are being finalized. Individual experiments are planned that involve analysis of new hearing protector technology under both laboratory and field conditions. The laboratory components are to consist of con-trolled studies using human subjects and/or an anthropometrically correct artificial test fixture to evaluate the adequacy/effectiveness of various hearing protective devices. Field studies are planned to determine the actual usefulness and practicality of the hearing protectors as used in diferent mining environments. Recommendations can then be offered to the mining community regarding correct earplug/earmuff usage that maximizes recognition of hazard/warning sounds while adequately protecting the miners’ hearing.

Jan 12, 2000

By G. R. Hopkins

One of the largest items in the expense of operating a refinery is the cost of the fuel used in distillation and for miscellaneous purposes such as in the heating of buildings and in the generation of electricity, On a B. t. u. basis, the average refinery consumes approximately one-tenth as much fuel as it produces. Theoretically, the fuel consumption at refineries should be much smaller than this, but furnaces can riot be designed to be 100 per cent efficient' and, in addition, a large part of the waste heat is low-temperature heat which would not pay for the expense of recovering it. Annual surveys of fuel consumption at refineries have been made by the United States Bureau of Mines, beginning with 1925. During the 5-year period, 1925-1929, the refineries made steady progress in fuel economy. This is evidenced by the Computed figures of heat requirement Per barrel of crude oil refined, which show a decline from 829,000 B. t. u. in 1925 to 639,000 B. t. u. in 1929 (see fig. 1). In 1930, however, the trend in fuel economy was reversed and the quantity of heat utilized in refining the average barrel of crude oil rose to 672,000 B. t. u. There were undoubtedly a number of reasons for the apparent decrease in fuel economy at refineries in 1930, chief of which were the tendency to carry the distillation farther instead of merely topping the crude and a gain in the consumption of waste oils, such as acid sludge, which in actual practice yield less heat per unit consumed than has been theoretically assigned to oil. The consumption of natural as fuel at refineries has declined since 1927, but this has been more than compensated by a rapid increase in the use of refinery or still gas. The total consumption of oil as refinery fuel in 1930 was not much below the 1925 total, but the consumption of coal has declined rapidly, so that in 1930 liquid and solid fuels contributed only 56 per cent of the total heat units- utilized at refineries as compared with 77 per cent in 1925 (see fig. 2).

Jan 1, 1931

By Charles E. Munroe

"It has been recently learned that certain foreign manufacturers are offering far importation into this country detonators at greatly reduced prices, some of these detonators being of such low grade (No.4), that their use would greatly increase the dangers in blasting.Detonators and electric detonators are used in initiating the explosion of the various high explosives that are now so extensively employed in a great variety of mining operations. Originally a large number of different grades (or ""strengths"") of detonators and electric detonators were marketed, the grade number indicating the weight of the charge of fulminating material contained in the copper case of the detonator. As late as 1914, a report of the Bureau of Mines (Bulletin 80, A primer an explosives for metal miners) shows that grades Nos. 3, 4, 5, 6, 7, and 8, containing from 0.54 to 2.00 grams each, were being offered for use. However, the writer bad observed as early as 1896, when the more insensitive types of explosives like nitro-substitution explosives began to be introduced for use in mining and other blasting operations, that use of a high-grade detonator was essential to insure certainty of discharge."

Mar 1, 1921

Minimize drilling time in roof bolting. Approach The Bureau of Mines conducted a survey of 34 roof bolting machines used in underground coal mines. Results of the survey indicated that drilling time, bit cost, and respirable dust concentrations and be reduced by using the appropriate bits for drilling, To evaluate bits currently used and to find optimum cutting parameters needed to minimize drilling time, the Bureau tested two bits commonly used in most underground mines on both wet and dry systems. These are the dusthog* and shank type. The dusthog has dust ports in the bit body to remove cuttings. With shank bits, holes in the drill steel do this. Cost of each type is roughly equal. Bolters with dry vacuum systems were tested in the laboratory first. The lab tests were verified by underground tests in several mines. Bolters with low-pressure wet drilling systems were also tested under-ground. Tests concentrated on the effect of rpm, water and airflow rates, heating, wear, bit design and bit type. Lab Results -Dry Drilling Holes were drilled during the laboratory tests using a production model bolter drilling 45-inch-deep holes into mixtures of lime stone and sandstone aggregate. All tests started with new shank and dusthog type bits at 225 and 450 rpm. Thrust was about 6,000 lbs in all tests. Each bit was tested at two airflows, 15 and 25 cfm, airflows which are typical on operating roof bolter bits. Eleven styles of bits were evaluated. On the average, dusthog bits drilled 25% faster than shank types and were always cooler after drilling. The effect of RPM was tested with 5 different bit types. When bit rpm was increased from 300 to 400, drilling rates doubled. With used, well-worn bits drilling time and final bit temperature were more than doubled.

Jan 1, 1986

By Gerrit V. R. Goodman, Jeffrey M. Listak, John A. Organiscak

Data on dust control practices, geology, and occupational exposures were gathered for approximately eighty underground continuous mining units. Despite silica contents in excess of 5%, nearly forty units successfully maintained silica concentrations at or below 100 µg/rn3 on a majority of occupational dust samples while the remainder had difficulty maintaining this level. These two sample sets were termed group A operations and group B operations, respectively. Analyses of productivities, geologies, and dust control parameters revealed only minor differences between these two groups. Subsequent analyses of face ventilation design showed considerable differences in silica exposure and silica content between group A and group B at the continuous mining machine and roof bolter operator occupations. These differences were minimal when using exhaust curtain ventilation with a dust scrubber', This face ventilation system may benefit operations having difficulty controlling silica dust exposure and silica dust content. Finally, the collected data showed that occupational samples from group B operations possessed generally higher silica exposures and silica content than similar samples from group A. The single head roof bolter (helper) possessed among the highest silica exposures and silica contents in both groups.

By H. S. Chiang, S. S. Peng

"SummaryAir velocity distribution surveys on four mechanized longwall faces are presented and discussed. Although there are discernible patterns in the velocity distribution, there are wide differences in distribution in the cases examined. This can be attributed to differences in mining and face geometry. An important factor is air leakage into the goaf.IntroductionOver the past two years several intensive air velocity surveys have been carried out in West Virginia coal mines as part of a programme aimed at understanding dust transport mechanisms on mechanized longwall faces. These are presented here and some of the patterns of velocity distribution are discussed.Ventilation survey methodologyThe air velocity vector consists of three mutually perpendicular subvectors; the vertical subvector is directed toward the roof, one of the horizontal subvectors is parallel to the coal face and the other pointing to the gob. The air velocity which was measured in this paper is the horizontal subvector parallel to the coal face.To record the velocity distributions at the longwall faces, the surveying stations and the surveying points were established as follows.(1) The first station usually was set at the third support from the headentry T-junction. Within the first few supports, the air coming from the intake airway encounters a sharp right-angle turn at the T-junction, and forms a turbulent region close to the coal face. The intake air in this region is also influenced by the motors that drive the face conveyer. But when the air reaches the different. But for the same face the number was the same. The main air-travelling area was divided into six to 12 equally sized sub-areas, and each surveying point was situated approximately at the centre of the sub-area.The velocity survey was carried out by two persons, one reading the meter and the other taking down the readings. A complete survey at one station took about 5-8 min. Usually, the dimension of the cross-sectional area was measured during that time.A third person used the smoke tubes to observe the following: (I) the air movement patterns at different locations; (2) the extent and the direction of the air leakage; and (3) the machines' influence on the main airflow. At the same time he observed and recorded the roof conditions and the compactness of the roof-caving in the gob."

Mar 1, 1989

By George S. Rice, L. C. IlsLey

"A remarkable explosion of fire-damp caused by a discharge of lightning at the new shaft at the Sitalpur coal mine, has been reported by the Chief Inspector of Mines of India, who gave the following details:""The explosion occurred during a thunderstorm, and the evidence showed that a flash of lightning had, to all appearances, passed down the shaft caus¬ing disruptive discharges at certain points between the guides and the winding rope, rending the latter at two places situated respectively .228 .feet and 278 feet from the surface, The distance between the winding rope and the side of the shaft was 5 feet 4 inches, indicating a spark gap ;of this width, and an intensity of discharge which could not fail to ignite the explosive mixture of gas and air known to be present in the shaft.""The Compressed Air Magazine, January 1920 issue, which contained the above extract also goes on to state;""In 1915, M, Ferey described in a paper read before the Societe de l'Industrie Minerale phenomena of a similar character to the above. In a pit liable to sudden outbursts of gas, for the sake of safety, shot firing was carried out from the surface. During a storm, in the year 1905, shots went off in two places after the detonators had been connected to the conductors) we read in the Colliery Guardian, London. These shots were situated respectively 1,400 and 1,410 metres from the firing station, Realizing the possible danger from this cause, the precaution was taken to cut the conductors at the bottom of the shaft and to connect there just before firing, Even under these conditions a shot went off spontaneously, -.owing, it is believed, to lightning."""

Feb 1, 1920

By Robert P. Vinson

The U.S. Bureau of Mines evaluated a light-scattering technique for discriminating between spherical and nonspherical particles. This evaluation was a three-step procedure. The first step required collecting light-scattering data for a variety of particles. This was accomplished with a particle analyzer called the DAWN-A. The DAWN-A measured the scattered light intensities of individual particles at a forward scattering angle of 40°. These DAWN-A measurements of individual particles are called scattering signatures by the Bureau researchers. The second step in this evaluation was to calculate a sphericity index number using the scattering signatures produced by the DAWN-A. The sphericity index number can range from 0 to 1. A calculated sphericity index of 1 would show that based on the intensity of scattered light, the particle was a perfect sphere. The third and final step of this evaluation was the comparison of the calculated sphericity indices of the various particles. Comparing these indices made it possible to discriminate between the nearly spherical waterdrops and the nonspherical coal and rock dust particles.

Jan 1, 1993

By Bill M. Stewart

The Bureau of Mines conducted laboratory tests to determine the effects on the physical properties of coarse coal waste of adding large amounts of fine coal waste. Maximum laboratory dry density, optimum moisture content, shear strength, and permeability tests were conducted on samples that contained 18 to 60 pct minus No.4 (U.S. Standard sieve size) coal waste. For the nonslaky materials, maximum laboratory densities were highest and permeabilities lowest when the samples contained between 30 and 40 pct minus No.4. Shear strength increased rapidly when the proportion of minus No. 4 was increased from 20 to 40 pct, but then increased only slightly or leveled off when the minus No. 4 was increased to 60 pct. Optimum moisture content and permeability were the physical properties most affected by the addition of fines. Optimum moisture content increased as much as 3 pct, and permeabilities decreased up to three orders of magnitude. Slaky coal waste material had physical property reactions to the addition of fines substantially different from those of nonslaky material.

Jan 1, 1981

By Douglas A. Donato

This Information Circular presents the MULSIM/PC system of numerical modeling computer programs developed by the U.S. Bureau of Mines. This system consists of four programs: PREMUL, the preprocessor or mesh generator; MULSIM/PC, the actual numerical modeling program (number cruncher); MUL3D, a three-dimensional postprocessor; and MUL2D, a two-dimensional postprocessor. These programs were specifically designed to operate on IBM-compatible (MS-DOS-based) personal computers for easy transfer of this technology to the mining industry and academia. MULSIM/PC uses a subvariation of the boundary-element method, namely, the displacement-discontinuity technique, for linear-elastic geomechanical analysis of mine plans in one or two parallel underground tabular deposits. Results calculated by this technique include stresses and displacements as they relate to changing mine geometries and materials. In addition to describing the MULSIM/PC program and its features, and providing a detailed example model, this report also documents the associated preprocessing and postprocessing programs that are part of the MULSIM/PC system. User's guides for all the programs are contained in the appendixes following the main report.

Jan 1, 1992

By Clarence O. Babcock

ROCK BEHAVIOR has proved of national interest in a variety of fields. The behavior of rock consequent to a nuclear blast was used to detect such blasts, as criteria for the design of underground military defense installations that would resist nuclear blasts, and for judging the feasibility for peaceful uses of nuclear explosives. An obvious peaceful application of nuclear explosives would be for large-scale rock excavation, and plans were presented during the year to improve the present Panama Canal or create a new canal by this method. These plans were based largely on earlier crater tests that demonstrated rock behavior when subjected to a buried nuclear blast. A knowledge of rock behavior under impact was used to evaluate the materials of the moon by means of the geometric configurations visible in the close-up pictures of the moon surface taken by the U.S. rocket Ranger 7. The composition of the moon must be considered in devising methods for taking samples of the surface layers or in designing underground shelters as bases for future explorations of the moon.

Jan 1, 1965

By Andrew B. Cecala, Edward D. Thimons, George W. Klinowski

The U.S. Bureau of Mines has designed and evaluated total mill ventilation systems at two different mineral processing operations. Both systems have proven very effective at reducing respirable dust levels throughout the mill in a cost-effective manner. A 25,500-cfm system installed at a clay processing mill provided approximately 10 air changes per hour. This system reduced respirable dust concentrations by approximately 40 pct throughout the mill building. The second evaluation was performed at a silica sand operation. Tests were performed with 50,000 and 100,000 cfm of ventilation to the mill building, corresponding to 17 and 34 air changes per hour. Average mill-wide respirable dust reductions were 36and 64 pct, respectively. Not only did these systems reduce respirable dust concentrations and increase visibility throughout the mills, they were also easy to install and required minimal maintenance. A total mill ventilation system provides a general purging of the mill air; the system should be viewed as a supplemental technique to assist other dust control systems in operation.

Jan 1, 1993

By Donald R. Irving

ALTHOUGH the quantity of material handled at metal and nonmetal mines in the United States in 1962 was 2.7 billion tons, the same as in 1961, a larger proportion was waste. At metal mines, crude ore production declined 1 million tons and waste output rose more than 18 million tons; at nonmetal mines crude ore production declined 6 million tons and waste output rose 36 million tons. Copper and iron ore producers increased their share of crude ore and material handled from about three-fourths to four-fifths of the national metals total, and sand and gravel and stone producers in-creased their share of the nonmetals total, also from three-fourths to four-fifths. Six States-Arizona, California, Florida, Michigan, Minnesota, and Utah-each handled more than 100 million tons of ore and waste, and together they accounted for 43 percent of the U.S. total. When the large-volume construction materials (sand and gravel and stone) were excluded from the totals, four States-Arizona, Florida, Minnesota, and Utah-supplied over half of the material handled.

Jan 1, 1963

By Franklin P. Hall

U.S. supply and demand data for utility electricity by States and regions were tabulated for the years 1960 and 1965. Estimates are provided of State-by-State quantitative data for the utility electricity industry that can be integrated into State and regional energy balances by source, form, and major consuming sectors, and used to determine basic flow-patterns. The difficult problem of compiling interstate and interregional shipments of electricity was resolved by (a) assuming the negligibility of interregional shipments and (b) deriving a theoretical line loss percentage used for determining interstate shipments. The data developed were able to show an estimated total supply of utility electricity available for consumption. The tables also report the distribution of the supply among the major consuming sectors (household and commercial, industrial, and transportation). To compare the various energy sources of utility electricity, quantities were converted to their British thermal unit (Btu) equivalents. The Federal Power Commission, Edison Electric Institute, and Bureau of Mines are the sources of the data used in this study.

Jan 1, 1969

By W. E. Lamont

The Bureau of Mines studied the potential for recovering marketable barite concentrates that meet oil well drilling-mud specifications from barite waste pond materials. The study was conducted as part of the Bureau's research program to conserve domestic mineral resources by advancing mineral recycling technology. The samples, which were obtained from Georgia, Nevada, Missouri, and Illinois, varied widely in character, particle size, and barite content. The samples were treated with sodium silicate and sodium cetyl-stearyl sulfate and then floated. The flotation flow sheet was modified to reject barren coarse and/or slime fractions from some of the samples, and one feed sample had to be scrubbed prior to flotation to remove residual flotation reagents. The cleaned concentrates had BaS04 contents ranging from 95.0 to 96.9 percent, while recovering 81.2 to 95.9 percent of the barite in the feed. The specific gravity of each concentrate exceeded the specification of 4.2. The removal of the flotation reagents from the flotation concentrate was not investigated.

Jan 1, 1982

By Ben A. Kornhauser

Benin's industrial sector experienced severe economic and financial problems in 1986, including disappointing performances of the Onigbolo cement plant and the Semé Oilfield, plus a shortage of technically trained personnel and experienced management. Oil production remained about 1,000 barrels per day. Import and export trade between Benin and the United States remained minimal. Because much of Benin's outstanding external debt was in U.S. dollars, the stronger dollar greatly increased the debt burden. The 1985 budget of $304 million' was composed of an investment budget of $194 million and a current budget of $110 million. Of the investment budget, 84% was expected to be externally financed. About $45 million was given to three priority projects: the joint Benin-Togo Nangbeto hydroelectric project scheduled for completion in 1986; drilling of new exploratory wells of the Semé petroleum project, and the Dassa-Parakou highway. The budget deficit was projected to exceed $43 million despite a decrease in projected revenue owing to an anticipated decline of 25% in import tax revenue, normally the largest source of Government revenue.

Jan 1, 1987

By D. R. Tesarik, R. W. McKibbin, J. B. Seymour

Displacement and stress changes in cemented backfill and ore pillars at the Buick Mine, near Boss, MO, were monitored by engineers from the U.S. Bureau of Mines and The Doe Run Co., St Louis, MO. A test area in this room-and-pillar mine was backfilled to provide support when remnant ore pillars were mined. Objectives of this research were to evaluate the effect of backfill on mine stability, observe backfill conditions during pillar removal, and calibrate a numeric model to be used to design other areas of the mine. Relative vertical displacements in the backfill were measured with embedment strain gauges and vertical extensometers. Other types of instruments used were earth pressure cells (to identify loading trends in the backfill), borehole extensometers (to measure relative displacement changes in the mine roof and support pillars),and biaxial stress meters (to measure stress changes in several support pillars and abutments). Two- and three-dimensional numeric codes were used to model the study area. With information from these codes and the installed instruments, two failed pillars were identified and rock mass properties were estimated.

Jan 1, 1995