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By D. K. Denton, J. M. Girard, D. F. Scott, T. J. Williams

Personnel from the Spokane Research Laboratory, National Institute for Occupational Safety and Health, examined an underground pillar at the Homestake Mine, Lead, SD. Investigations involved strain relief and seismic tomography studies in the mine, and ultrasonic velocity measurements on pillar core in the laboratory. Measured octahedral normal stress was 37 MPa (5,366 psi); seismic P-wave velocities averaged 5.2 km/s (17,060 ft/s); and ultrasonic velocities at a pressure of 39.6 MPa (5,750 psi) averaged 6.3 km/s (20,669 ft/s). The difference between in-mine and laboratory velocities is attributed to the attenuation of seismic energy by mine fractures larger and more numerous than those in the samples of core measured in the laboratory. Using these results, researchers hypothesize that pillar rocks have the ability to withstand stress an order of magnitude greater than they currently sustain.

By J. J. Demeter

Experiments were conducted in 2- and 4-inch-diameter standpipes to evaluate the effectiveness of standpipes as pressure seals. During the experiments, these standpipes conveyed Alan-Wood magnetite (60 to 230 U.S. standard sieve mesh) by gravity flow from one vessel to another of relatively higher pressure. The information obtained has been helpful in a Federal Bureau of Mines investigation of how to make either synthesis gas or hydrogen by a modified steam-iron process employing a continuous recycling stream of granular iron-iron oxide at temperatures of 600° to 900° C. In this process the mixture of granular material flows by gravity from a reduction vessel at low pressures to an oxidation vessel at higher pressures. Data from the 2- and 4-inch-diameter standpipes indicate that it would be practical to use a standpipe as a pressure seal between the reductor and oxidizer. Investigators found that, by gravity flow, the standpipe could convey the Alan-Wood magnetite against pressure gradients up to 1.07 pounds per square inch per foot of column height.

Jan 1, 1961

By Albert L. Toenges

A phase in strip mining of bituminous coal is the overturning of the surface of the land. The purpose of this report is to acquaint the operators and others interested in stripping with the work that has been done in certain States to reclaim the surface of land from which the coal has been removed by this method of raining. The preparation of this manuscript follows an extensive study of the subject in the field in the course of which a large number of strip mines were visited. ACKNOWLEDGMENT The information used in the report was obtained through the courtesy and cooperation of the operators of the mines visited, State officials and educational institutions, and others interested in the subject.

Jan 1, 1939

By Gerald V. Gibbs

Quadratic functions, Q(hkl), are given to six places in increments of 0.01° for 2? from 0° to 90° for CuKa and from 25° to 180° for CuKa1. The wavelengths used for Cu in the computation are those agreed upon by the Editorial Commission of the International Tables for X-ray Crystallography (1950): CuKal 1.54051 A.; CuKa2 1.54433 A. INTRODUCTION At the Federal Bureau of Mines laboratory, Norris, Tenn., X-ray diffraction crystallography using tubes with copper targets revealed a need for a handy reference for the quadratic functions of copper radiation. The tables presented here were prepared to satisfy that need. The quadratic form Q(hkl) may be expressed in terms of the Bragg diffraction angle 2? and of the wavelength ? as

Jan 1, 1961

By Steve Signer, Ed Mchugh

Recent studies by researchers from the National Institute for Occupational Safety and Health indicate that shear loading contributes significantly to failure of bolts used for rock reinforcement in coal mine roofs, Laboratory tests on 17 bolts were conducted to study the behavior of roof bolts subjected to shear loading over a range of axial bolt loads, Fourteen strain gauges were attached to each bolt to measure axial and bending loads at seven locations along its length. The instrumented bolts were grouted through two high-strength concrete blocks, and axial tension was applied to as much as 75% of yield strength. With the block interface acting as a failure plane, shear loads were applied to the blocks at a constant rate of displacement to the ultimate strength of the bolts. The tests characterized the relationship of axial bolt loads to shear forces across a rock bedding plane and measured the distribution of axial and bending strain along the length of the bolts. 'These results will improve the selection of roof reinforcement in mine areas where high shear stresses are present, thus improving the safety of miners working in these areas.

By J. Koster

In the western United States occurs deposits of low-grade chromite which, when concentrated, may be reduced to ferrochromiun in electric furnaces that derive energy from dams and hydro plants now in course of construction. Montana ore was chosen for the experiments. A 1-ton sample contained 26 percent Cr203, 17 percent Fed, and 17 percent SiO2, plus other constituents, and the concentrates therefrom assayed 44 -percent Cr203, 23 percent FeO, and 0,79 per cent SiO2, Gravity concentration was found to be the best method. Ferrochromiums are of two grades - high-carbon with 66 to 70 percent chromium and 4-112 to 6 percent carbon and low-carbor with 67 to 72 percent chromium and 0.6 to 2 percent carbon. Both are made in electric furnaces that use anthracite as a reducer and suit-able fluxes. The concentrates mentioned mere smelted under different conditions, and it was concluded that domestic ore could be reduced with anthracite to produce a ferrochromium of S to 10 percent carbon content at yields of 90 percent without re-treating the slag. This carbon may be lowered to required proportion with calcium and silicon, but the former requires a great excess and the latter leaves an alloy high in silicon. INTRODUCTION Chromite occurs in several regions of the United States, but the known deposits of this mineral have not been large enough or high grade enough to permit them to compete under normal conditions with imported ores. There are numerous deposits of chrome ore along the West coast. These are generally conceded to be relatively small, although some were worked during the World War. There are some indications of a revival of interest in California chromites. Montana contains large chromite deposits in Stillwater and Sweetgrass Counties. The utilization of chromite for ferrochromium and. the manufacture of stainless steels is distinctly an electrometallurgical problem; consequently, a study of methods for treatment of chromite might pave the way for the establishment of new electrometallurgical industries in the Western States. This thought is supported by the cheap power that is soon to become available from the western dams, Farther, submarginal domestic chrome deposits might thus be turned into profitable producers.

Jan 1, 1936

By Richard Quirk

This report describes methods and techniques employed by The Glidden Co. of Cleveland, Ohio, in explorating an ilmenite-bearing sand deposit in Ocean County, New Jersey, during 1960 to determine ore reserve potential and the feasibility of mining and establishing a milling plant on the property for the production of ilmenite concentrate. The property covered approximately 1,250 acres. Comprehensive sampling by water-jet drilling indicated the deposit averaged 20 feet in thickness and contained 4.5 percent heavy minerals, of which 80 to 85 percent was ilmenite and leucoxene. Average depth of the water table as determined by auger boring was 16.8 feet. Pilot plant tests indicated that circular concentrators in combination with spiral concentrators would recover at least 80 percent of the heavy mineral content of the sands. It was estimated that sufficient ore reserve tonnage had been developed to supply the company's Baltimore chemicals division, pigments department, with a suitable grade ilmenite concentrate for a period of 20 years at the present rate of pigments production. The property was designated as Lakehurst mine and plans are in progress for mining development and plant construction.

Jan 1, 1963

By J. Koster

In the western United States occurs deposits of low-grade chromite which, when concentrated, may be reduced to ferrochromiun in electric furnaces that derive energy from dams and hydro plants now in course of construction. Montana ore was chosen for the experiments. A 1-ton sample contained 26 percent Cr203, 17 percent Fed, and 17 percent SiO2, plus other constituents, and the concentrates therefrom assayed 44 -percent Cr203, 23 percent FeO, and 0.79 per cent SiO2, Gravity concentration was found to be the best method. Ferrochromiums are of two grades - high-carbon with 66 to 70 percent chromium and 4-112 to 6 percent carbon and low-carbor with 67 to 72 percent chromium and 0.6 to 2 percent carbon. Both are made in electric furnaces that use anthracite as a reducer and suit-able fluxes. The concentrates mentioned mere smelted under different conditions, and it was concluded that domestic ore could be reduced with anthracite to produce a ferrochromium of S to 10 percent carbon content at yields of 90 percent without retreating the slag. This carbon may be lowered to required proportion with calcium and silicon, but the former requires a great excess and the latter leaves an alloy high in silicon. INTRODUCTION Chromite occurs in several regions of the United States, but the known deposits of this mineral have not been large enough or high grade enough to permit them to compete under normal conditions with imported ores. There are numerous deposits of chrome ore along the West coast. These are generally conceded to be relatively small, although some -were worked during the World War. There are some indications of a revival of interest in California chromites. Montana contains large chromite deposits in Stillwater and Sweetgrass Counties. The utilization of chromite for ferrochromium and. the manufacture of stainless steels is distinctly an electrometallurgical problem; consequently, a study of methods for treatment of chromite might pave the way for the establishment of new electrometallurgical industries in the Western States. This thought is supported by the cheap power that is soon to become available from the western dams. Farther, submarginal domestic chrome deposits might thus be turned into profitable producers.

Jan 1, 1936

By Robert H. Peters

Groundfall accidents have been the leading cause of fatalities in the underground coal mining industry for many years. Statistics from the Mine Safety and Health Administration (MSHA) indicate that approximately half of the victims of these fatal accidents were in an area where no devices had been installed to support the mine roof. This report was prepared by the U.S. Bureau of Mines to provide guidance to operators of underground mines concerning the use of techniques that may help to keep miners from going under unsupported mine roof. The report is divided into two major sections. The first section reviews the findings from several areas of empirical research pertaining to strategies for convincing employees to avoid unsafe acts and/or adopt self-protective behaviors. The strategies are (1) incentives and feedback, (2) disciplinary actions, (3) training (primarily fear communications and behavioral modeling), and (4) nondirective techniques. This literature review has a broad focus and should be helpful in making decisions about how to encourage a wide variety of types of self-protective behaviors. The second major section of the report presents an analysis of each strategy's potential for keeping miners away from unsupported roof.

Jan 1, 1991

By Eleanor Abshire

THIS PUBLICATION is the third to be prepared as a result of a cooperative project by the Bureau of Ships and the Bureau of Mines for accumulating literature published on zirconium and hafnium. The undertaking also resulted in the establishment of an information center on zirconium and hafnium at the Bureau of Mines station at Albany, Oreg., for the use of research organizations and others. The present bibliography consists of references (with abstracts) to pertinent literature on zirconium. The first publication in this series was Information Circular 7771, Bibliography of Zirconium, published in April 1957. It consists of 969 abstracted reports and 645 U.S. and foreign patents. The second publication, called a supplement to Information Circular 7771, is numbered Information Circular 7830 and consists of 844 abstracted reports and 62 U.S. and foreign patents. It was published in October 1958.

Jan 1, 1962

By A. J. Kraemer

For a number of years the Bureau of Mines has been conducting an investigation of crude petroleum from producing fields in the United States and the Western Hemisphere and has published a series of reports on these fields. Analyses of crude-oil samples tom some oil fields of Louisiana are given in Bulletin 291.4/ Analyses of 26 representative crude oils from various producing formations of southern Louisiana are given in is report. These.samples are from 14 field's in 10 parishes in the southern part of the State, usually designated as the "Louisiana Gulf Coast area." ACKNOWLEDGMENTS Thanks are due the representatives of the various companies from whom samples were obtained for their cooperation and assistance in helping to secure representative samples. The samples were analyzed under the direction of E. C. Lane at the Bartlesville station of the Bureau of Mines.

Jan 1, 1934

By G. B. Shea

In the search for possible future sources of petroleum products, the recovery and utilization of bitumens from the large outcropping deposits of bituminous sandstones in the United States have been under study by the Bureau of Mines for the past several years. The results of laboratory research in the adaptation of the hot-water separation process to recovery of bitumen from bituminous sandstones were reported in an earlier publication, on the Edna deposits near San Luis Obispo, Calif. This publication included analytical data on the cracked products and asphalts obtained from the extracted bitumen and on the cracking and distillation of the bitumen. Comparable hot-water separation tests have been run in the San Francisco, Calif., laboratory of the Bureau of Mines on quarry samples from the large deposits of bituminous sandstones near Vernal and Sunnyside, Utah. The bitumens were isolated from the extracts of the separation plant and analyzed at the Petroleum and Oil-Shale Experiment Station of the Bureau of Mines, Laramie, Wyo. Part I of this report summarizes the general characteristics of the Vernal and Sunnyside deposits and discusses the hot-water separation process as applied to those bituminous sandstones and the results obtained. The separation tests showed that these bituminous sandstones also respond to treatment by the hotwater method of separation. The bitumen in the Vernal sandstone was extracted more readily by the action of hot water than was the Edna bitumen, which greatly simplified plant operation. The Vernal sandstone contains no water-soluble iron compounds, such as were found in the Edna sandstone, and, therefore, required no preliminary water washing. Recovery of bitumen from the Vernal sandstone was about 96 percent.

Jan 1, 1952

By J. F. Neill, O&apos

The manganiferous schists occurring in the vicinity of Kings Mountain, North and South Carolina, suggest significant tonnages of potential submarginal ores. Although some reconnaissance work in connection with these deposits has been reported, no recent information has been published. Evaluation of the schists as a possible domestic manganese resource has not always adequately considered the fact that the manganese content occurs quantitatively both as oxide and as the silicate, spessartite. The Bureau of Mines investigation herein reported includes preliminary studies to indicate the extent of manganese oxide mineralization and to deter-mine the amenability of the material to sulfur dioxide leaching. The field reconnaissance studies suggest a resource containing in one area an average of 6.4 percent manganese as oxide. The procurement of depth information was beyond the scope of the investigation.

Jan 1, 1962

By J. C. Kerkering, S. M. Miller, P. C. McWilliams

Researchers at the U.S. Bureau of Mines investigated the use of close-range photogrammetry and subsequent stereo digitizing to obtain data from rock fracture roughness profiles. The photogrammetric process yielded results that were acceptable but somewhat inferior to those obtained by a mechanical profilometer. On the basis of this study, further pursuit of photogrammetry as a data collection method in mining is proposed. Fractal geometry was investigated as a means of measuring the roughness of rock fracture profiles. Four fractal algorithms were used: divider method, modified divider method, box method, and spectral method. A comparison of the methods gave ambiguous results. Brown's modified divider method provided the best means of obtaining the fractal dimension. Shear strength estimates were obtained using the parameters of the modified divider method and Myers' Z, measure. Because of differences in results when comparing the different ways of obtaining the fractal dimension, future users of fractals in studies of rock fractures are advised to cross-check their results carefully.

Jan 1, 1993

By W. H. Schiffbauer

NIOSH has developed an active proximity warning system called HASARD (Hazardous Area Signaling and Ranging Device) for warning workers as they approach known dangerous areas around heavy mining equipment and other dangerous work zones. HASARD is composed of a transmitter and a receiver. The transmitter generates a 60-kHz magnetic field using one or more wire loop antennas. Each antenna is adjusted to establish a magnetic field pattern for each hazardous area. The receiver, worn by the worker, is a magnetic field strength meter. The received signal is compared against preset levels which are calibrated to identify levels of danger. The receiver outputs can include visual, audible, and vibratory indicators and it can also be made to disable machine functions. HASARD was field tested on a Joy 12 continuous miner, a Komatsu 210 M Haulpak, and on a highwall launch vehicle. Slight modifications were made for each application. HASARD provided warnings as designed and proved to be rugged enough to withstand the harshest of production environments.

By Dana C. Reinke

Water well drillers are exposed to high levels of noise while working. NIOSH researchers have found that water well drillers are exposed to levels above 85dB (A) while performing certain tasks during a typical drilling job. Noise levels consistently over 85dB (A) during an 8–hour work shift are hazardous and can lead to hearing loss in workers. Finding ways to reduce noise exposure is difficult because of many factors. The work environment is constantly changing due to the location of jobs and environmental factors. The types of drill rigs required for drilling are expensive. Equipment can range from new to used (10 to 30+ years old). Drillers and owners can work together to prevent noise–induced hearing loss, and measures can be taken to reduce exposure to hazardous noise.[ ] Preventing hearing loss occurs through three stages. The first stage is removing noise from the source (i.e., drill rig). Various parts of a drill rig create noise besides the drilling rod. NIOSH researchers have examined noise levels of drill rigs. Some of the loudest parts of the drill rig include the compressor, engine, and cooling fan (Fig. 1). While removing the noise source from a worksite is ideal, the process would be expensive and difficult.[ ]

Jan 9, 2005

By Travis Q. Lyday

During 1983, Ecuador's gross domestic product (GDP) decreased by a reported 3.3% in real terms, the second consecutive decline in the economy after more than a decade of growth generated mainly by petroleum export revenues. The slowdown was due, in part, to the effects of the world recession, lower foreign demand for oil, depressed world oil prices, and reduced demand and prices for Ecuador's traditional agricultural exports. Inflation accelerated to an estimated 55% annual rate. The sucre was devalued in March, for the second time in less than a 12-month period, by 27% after remaining unchanged during the previous decade. In addition, continuous adjustments were made every weekday, effectively devaluing the sucre another 30% by yearend. Ecuador's production of crude petroleum increased almost 12% in 1983 compared with that of 1982. Average daily production was 237,100 barrels per day (bbl/d), up from 211,300 bbl/d in 1982.

Jan 1, 1985

By R. August Heindl

A process for recovering manganese from open-hearth steel-plant slags was investigated. The proposed method of accomplishing this is indicated by the flow diagram in figure 1. Mixtures of open-hearth, steel-plant flush slags and limestone, so proportioned as to have molar [CaO -3P205] ratios of approximately 2, were fired at approximately 2,400° F. in an oxidizing atmosphere and then cooled slowly. This treatment produced a clinker consisting principally of two solid phases comprised of (1) various combinations of the oxides of manganese, iron, aluminum, and magnesium, probably in spinel complexes, and (2) a dicalcium silicate phase, which contains the phosphorus. Reduction of these clinkers with hydrogen or with gaseous mixtures containing CO, CH4, and other hydrocarbons at about 1,300° F. formed manganous oxide as well as varying amounts of ferrous oxide and iron. Carbon monoxide and mixtures of hydrogen and carbon monoxide effectively reduced the clinkers but also gave higher proportions of soluble iron when the manganese was extracted from the reduced clinkers by leaching at about 80° F. with ammonium carbonate solutions containing 26 to 28 percent ammonia and 15 to 26 percent carbon dioxide. It is believed that the manganese is in solution as an ammonia-manganese complex. Concentrations of about 90 grams of manganese per liter were obtained by batch countercurrent procedures. By distilling 50 percent of the ammonia, the ammonia-manganese complex was decomposed, and approximately 90 percent of the manganese was precipitated as the carbonate with the simultaneous precipitation of 15 to 30 percent of the iron, the larger amounts of iron precipitating in the continuous tests. The manganese-iron ratio in the product could be increased either by recycling more manganese from the distillation to the extraction or by aerating the liquor to purge it of iron before, rather than after, the distillation step. Calcination of the pelletized manganese carbonate in an oxidizing stmosphere at 2,000° F. or above gave a final product, Mn304, resistant to crushing and apparently possessing the other physical properties essential in a ferromanganese blast-furnace feed.

Jan 1, 1955

By Dana C. Reinke

A job analysis is a written list of the tasks associated with doing a particular job. In drilling, describing the steps associated with adding rod to the drill steel would be an example of a task associated with the job. How to hammer casing or fish a lost drill bit out of a hole would also be job tasks. Develop a written list of job tasks. Ask drillers in your company if the tasks listed are correct and accurately reflect how to perform the job. While each driller may do the job a little differently, some tried?and?true methods are required to perform certain tasks safely and correctly. You may find a separate analysis is needed for different drilling jobs (e.g., a residential well or a monitoring well). Also remember to include the tasks of both the helper and the driller.

Jan 1, 2005

By D. A. Elkins

This report is the second of a series of three that will evaluate, in order, the metallothermic, carbothermic, and electrolytic methods of magnesium production. The historical development of the carbothermic process is outlined. Production costs varying from 38.9 to 21.8 cents per pound of magnesium are estimated for different versions of the process. Additional suggested process modifications are listed. The technical and economic potential of the different versions are compared. Areas deemed most promising for future research on the process are delineated.

Jan 1, 1967