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By E. D. Gardner

The American petroleum industry is supplying the present domestic demand for liquid fuels. Known reserves of petroleum in the ground, however, are limited, and the .cost per barrel of finding new oil pools is increasing. Any deficiencies of domestic production in the near future doubtlessly could be made up by imports: Dependence upon foreign oil for part of our industrial requirements is not necessarily cause for alarm, but in time of war an adequate, dependable, domestic source of liquid fuels is vital to the defense of the country. As a national defense measure, and to insure a future continuous oil supply for our economic machine, it would appear logical to take steps now to develop methods for producing petroleum substitutes within our own borders. This undoubtedly was in the mind of Congress when it passed the Synthetic Liquid Fuels Act (58 stat.190; 30 U. S. C. Sup. Secs. 321-325), Approved April 5, 1944.The title' of the Law reads: An Act authorizing the construction and operation of demonstration plants to produce synthetic liquid fuels from coal, oil shales, agricultural and forestry products, and other substances, in order to aid the prosecution of the war, to conserve and increase the oil resources of the Nation, and for other purposes. Congress authorized $30,000,000 for a 5-year program and directed the Bureau of Mines to carry it out. The part of the program pertaining to oil shale is being conducted on Naval Oil-Shale Reserves Nos. 1 and 3 (fig. 1) at Anvil Points, near Rifle, Colo.

Jan 1, 1948

By William W. Adams

The stone-quarrying industry of the United States, including such related operations as rock crushing, rock dressing, and the manufacture of cement and lime, reported a larger volume of employment in 1934 than in 1933. Reports from the operating companies to the United States Bureau of Mines showed an increase in the number of men employed, number of man-days of employment, and total number of man-hours of labor performed during the year. Moreover, the average worker had a longer period of employment during 1934, the gain amounting to 11 percent over 1933. The increase in employment was accompanied by no increase in accidents for the industry as a whole; in fact, the accident rate for 1934 was a fraction lower than the rate for 1933. In some branches of the industry the frequency of accidents increased, but these increases were more than offset by reductions in rates for other branches. Reports for 1934 were received from 1,403 active plants. The working force averaged 64,331 men for 204 days per man, and the total period of employment for all of the men was 95,258,880 man-hours. Each employee averaged 1,481 hours of work during the year. The total number of hours of labor represented a gain of more than 8 percent, and the average working time per employee showed a gain of 62 hours per man.

Jan 1, 1936

The following pages discuss the objectives, the background, the scope and a statement of the problem of the study of methods to improve the pillar extraction practices in underground coal mines. 1. OBJECTIVES The objectives of this project were: ? to determine the principal factors contributing to high accident frequency and severity in both conventional and continuous mining operations; ? to compare and evaluate the safety aspects of the "open end" and "split and fender" systems of pillar mining; to establish basic data required to decide what constitutes an adequate pillaring plan that will optimize efficiency, recovery, and safety; ? to determine what measurements or information should be collected, (e.g. roof sag, pillar stress,) to make on-the-spot judgment of impending roof or pillar collapse; ? to make recommendations to improve existing methods or to insure proper techniques are implemented, and ? to suggest areas where additional studies or new research may be of value.

Jan 1, 1975

By Wilbur I. Duvall, S. L. Windes, Leonard Obert

"Previous investigations, too numerous to be listed in entirety, have been performed to determine the physical properties of rock. When considered according to their objectives, most of these investigations can be grouped as follows: First, the geologic group (1,2),4/ in which the purpose was to obtain information on the physical properties of the rocks that make up the earth's crust. Particular emphasis has been placed on the determination of the elastic constants--that is, Young's modulus, the modules of rigidity, and Poisson's ratio – as these quantities determine the propagation characteristics of seismic waves. Second, the structural properties group (3 - 11), in which the physical properties of architectural or monumental stone, concrete and aggregate rock, road blocks (cobblestone), and the like were desired. The tests have been quite general and include, besides the elastic properties; the compressive and tensile strength, and the toughness, hardness, and weathering properties of many types of rocks.To .a lesser degree, investigations have been carried out to determine the physical properties of mine rock. A few reports (12 - 14) present data on the crushability and grindability of mine rock, and a large number of papers discuss grinding and crushing procedures and methods of analyzing the data (for example, see references 15 - 17). Some of the latter group also have given the results of tests on mine rock; however, comparatively few include an adequate petrographic description or information on other physical properties of the rock. A few papers,(18 - 22) have reported studies of the strength of rock specimens in respect to the strength of parts of mine structures, such as pillars, roof, arches, etc. Other papers (23 - 26) have discussed investigations on such subjects as primary and secondary crushing, diamond and pneumatic rock drilling, explosive breaking and shattering of rock, rate of drifting and miring, and other allied problems. The majority of these reports have given no more than a cursory, description of the rocks and have included no statement regarding the physical properties. When statements have been given regarding the physical properties, they have usually referred only to isolated tests, making correlations between variations in the physical properties and variations in the .test under consideration difficult, if not impossible. Some reports have included handbook values on such characteristics as the crushing strength, hardness, and toughness. This practice is not satisfactory, because these values are usually given for col¬lective types of rocks, such as granites, limestones, and marbles, and it is known that the variations of the physical properties within these groups is often larger than the differences between the groups."

Aug 1, 1946

By William W. Adams

Accidents to men employed in the quarrying and related industries of the United States were more numerous, absolutely and relatively, in 1937 than in 1936. Fortunately, the entire increase was in the category of nonfatal injuries, as accidents causing death declined in number and in proportion to the number of man-hours worked. Employment increased. More men were employed, more man-days and man-hours were worked, and the average employee had more hours of work than in 1936. Reports covering all commercial operations showed that 84,094 men were employed an increase of 5.1 percent over 1936. The number of man-hours of work performed by the industry was, 158 millions, an increase of 7.6 percent. Seventy-seven men were killed by accidents, a, reduction of 14 from the year before, and 6,348 men were injured and disabled for more than the remainder of the day on which the accident occurred, 11 percent more than in 1936. The fatality rate of 0.49 per million man-hours of exposure in 1937 compared favorably with the rate of 0.62 for the previous year, whereas the non-fatal-injury rate of 40.10 was 3.2 percent higher than the rate of 38.87 for 1936.

Jan 1, 1940

By R. J. Matetic

The Bureau of Mines, as part of a program to improve mine planning and development, is currently investigating the effects of pillar load transfer, which can impact mining operations within a multiple-seam configuration. A comparative study was performed at two separate mine sites. The objective of this study was to compare two mines, each affected by this pillar load transfer mechanism, and to show how this interaction affected underground workings by the installing and monitoring underground instrumentation. At mine site A where the overburden was 1,000 ft, the innerburden thickness was less than a pillar width (40 to 45 ft), overlays of the mine layout show pillars were not superpositioned, excessive roof to floor convergence was measured, and pressure readings indicated pillar core loading only. At mine site B, the overburden was approximately 555 ft, the innerburden thickness was approximately 105 ft, overlays of the mine layout show pillars were superpositioned, minimal roof to floor convergence was measured, and pressure readings indicated a skin loading only.

Jan 1, 1988

By Thomas A. Davidson

The Bureau of Mines Helium Field Operations has developed a simple and accurate method for calculating the viscosity of gas mixtures. Only the composition of the mixture and the molecular weights and viscosities of the pure components in the mixture are required. The momentum fraction of a mixture is calculated from the composition. The fluidity is calculated as a quadratic function of the momentum fractions. The efficiency factor for transfer of momentum in collisions between bodies of different masses is derived and used with one empirical constant. The viscosity is the reciprocal of the fluidity. Results of the method are compared with 752 reported viscosities for 40 dilute binary systems at temperatures from -78 to 276.9°C. Using this method the average absolute deviation is 1.29%, the root-mean-square deviation is 1.99%, and the average deviation is -0.84%.

Jan 1, 2010

By John P. Carter

The U.S. Bureau of Mines conducted research to determine suitable construction materials for use in brine and steam environments produced from high-salinity geothermal brines. The high-temperature, high-salinity geothermal brines in the Salton Sea Known Geothermal Resources Area (KGRA) are a valuable source of energy and mineral values. The brine and steam produced from them are corrosive and cause early failure of many common materials of construction. Mass-loss and electrochemical corrosion measurements were conducted on over 60 metal alloys in brine and steam environments produced from geothermal well Magmamax No.1, located at the Salton Sea KGRA, at temperatures from 1800 to 2150 C, and in synthetic Magmamax brine at 105° and 232° C. General corrosion, crevice and pitting corrosion, and stress corrosion were examined along with the effects of dissolved gases. The alloys with the most acceptable corrosion performance in high-temperature, high-salinity geothermal environments were the high-chromium ferritic stainless steels, the Inconels and Hastelloys, and the titanium alloys. Specific alloys that performed well in wellhead brine included Fe29Cr4Mo, E-Brite 26-1, stabilized Fe26Cr1Mo, 6X, Inconel 625, Hastelloy C-276, Hastelloy S, Hastelloy G, Ti5OA, TiO.2Pd, and TiCode 12.

Jan 1, 2010

By Paul L. Michael

This report presents a discussion of perforance parameters for electronic or active hearing protectors that will meet the needs of underground coal miners. This information is incorporated into a proposed set of specifications that can be used to judge the suitability of a particular electronic hearing protector for the coal mine application. Acoustic and electrical tests were performed on a developmental model of an electronic hearing protector built by the U. S. Bureau of Mines. This model showed only a slight reduction in speech intelligibility which was traced to poorly matched components and in particular to the transducers. Tests of alternative components showed the Knowles BL-1671 microphone to be suitable for this application because of its performance and extremely small size. The Roan-well H-143/AIC earphone was found to have a good frequency response but has the disadvantage of being rather bulky which causes a slight degradation of a low frequency attenuation of the hearing protector. A satisfactory installation of these components in a hearing protector muff was demonstrated and tested. Results of tests of several methods of controlling the sound level under the hearing protector muff showed that a simple diode clipper circuit can be used with only a negligible loss in speech intelligibility for normal-hearing listeners. A commercially available active hearing protector, the British-built ACOS A-9000/2 was examined. This hearing protector provides sound level limiting through a saturating amplifier. Preliminary tests have shown that the performance characteristics of this commercial unit meet many of the proposed specifications so further testing and evaluation should be performed to determine its suitability for use 1n underground coal mines. The recommended test of intelligibility for electronic hearing protectors and other communication systems as used in a coal mine setting is the Modified Rhyme Test (MRT) developed by House et al. in 1965. The suitability and method of administering this test are discussed.

Jan 1, 1976

By Kenneth M. Smith

"The kaolin deposits of Aiken County, South Carolina (fig. 1), have been worked continuously since 1852. It has been long known that the deposits contain a high percentage of alumina and that large reserves exist. These facts led to the early selection of this area for examination in the search by the Bureau of Mines for high-alumina clays. An exploratory program was started by the Bureau, and drilling was carried on from June 27, 1942, to October 31, 1942.The kaolin-bearing district occupies an area approximately 25 miles long and 11 miles wide, running northeast, with its center at Aiken, S. C. (fig. 1). Within this district, a triangular area bounded by Horse Creek, Silver Bluff Road, and Hamburg Road was roughly prospected by boring 43 machine and 12 hand holes. As a result of the data obtained, a final smaller area was chosen for more systematic prospecting. This area is bounded by Pine Log, Tewkesbury, Silver Bluff, and Craig Sawmill Roads and covers about 4,000 acres.Mineral exploration agreements covering 11,272 acres were signed by 35 property owners, and 11,956 feet was drilled in 200 holes on these properties.The Bureau of Mines exploration work in the district has indicated 19,514,000 short tons of kaolin, of which approximately 10,000,000 tons would average over 35 percent alumina.The tonnages and grades of kaolin developed by this exploration are tabulated below.All grades of this kaolin average approximately 2 percent Fe203 and 1.5 percent Ti02.This project was under the general supervision of J. R. Thoenen, supervising engineer, Non-Metals Mining Section of the Mining Division, Bureau of Mines, until July 1942. The -project was then under the general supervision of E. J. Lintner and later Rowe McCrae, consecutively district engineers for Georgia, South Carolina, and Florida. The final report was prepared, under the general supervision of V..J. Lynch, chief, Raleigh Branch, Mining Division, by William A. Beck from the original report by the author.Acknowledgment is made for the wholehearted cooperation and assistance given to the Bureau of Mines by the various operating companies in the district. Particular thanks are due Theodore Henderson, general manager; North American Clay Co., Wilbur Driver, general manager, and Howard Driver, assistant general manager, The Huber Clay Co.; H. W. Smith, president, The South Carolina Clay Co.; and J. Richard Parker, president, J. R. Parker Clay Co., all of Bath S. C.; J. B. Howard, Jr., superintendent/ the Immaculate Kaolin Co., Langley, S. C.; Richard Jones, president, National Kaolin Co., and William Winans, president, The Southern Clay Co., both of Aiken, S. C.; and W. S. Burkalter, Warrensville, S. C.Acknowledgment is also due the Metallurgical Division for analytical determinations and to James J. Page of the Federal Geological Survey for his aid in mapping and logging the holes.The first known use of kaolin from this district was by the Bath Pottery Co., which began mining an outcrop in Horse Creek Valley, near Bath, in 1852.. In 1867, R. McNamee, of New York City, acquired this pit and continued mining. This first mine is still known as the McNamee, and from its operation grew the present kaolin industry of South Carolina."

Dec 1, 1949

By C. Thomas Hillman

The practical concern of economic minability of large, high-grade manganese nodule deposits in the northeast Pacific Ocean is addressed in this Bureau of Mines report. Principal objectives are to (1) estimate tonnage and grade of deposits with significant potential and (2) describe and estimate profitability of operations designed to mine and process deposits with greatest apparent potential. Analysis of data from over 800 ship stations identified three areas for detailed study. Average metal contents of these areas range from 1.30 to 1.45 wt pet nickel, 1.00 to 1.24 wt pct copper, 0.21 to 0.26 wt pct cobalt, and 26.8 to 27.8 wt pct manganese. Estimated recoverable nodule resources are 67.0, 66.9, and 148.8 million dry metric tons (t). A system to mine, transport, and process nodules from the three sites is described and costed. Although hypothetical, the system utilizes hydraulic mining and Cuprion (Kennecott) processing, which have been successfully tested at pilot scale. Nickel, copper, and cobalt are the three primary products, but ferromanganese is a considered option. Estimated capital requirements are approximately $1.5 to $1.7 billion for three-metal production. If ferromanganese were recovered, an additional investment of about $130 million would be required. Operating costs range from $71 to $83 per dry metric ton of nodules without manganese, and from $103 to $123 per dry metric ton with ferromanganese. Discounted cash flow analyses predict low returns, ranging from 2.7 to 5.2 pct with ferromanganese and from 4.1 to 6.0 pct without.

Jan 1, 1983

By Clark P. Mangelsdorf

The report consists of two parts. In Part I is a state-of the-act study of roof truss technology as of January 1979. Included are a history of the truss concept, a review of analysis techniques, a record of hardware available and equipment used in its installation and numerous examples of user experience. Part II is concerned with a study of the role of friction in the behavior of a roof truss. The appendices include laboratory tests by the author.

Jan 1, 1979

By Jonathan Ludlow

This document is the final report of a study aimed at defining the relative contributions of various sources of respirable airborne dust on longwall faces. In order to define the contribution of various primary sources, continuous dust level data were recorded on five longwalls for an average of five shifts at each. By analysis of these data with records of face activity, it was possible to determine the overall contribution of each of the major elements of the longwall system to overall respirable dust exposure at various face locations. Average levels were determined for roof support generated dust, conveyor and intake dust and for dust levels during various shearer activities. When average levels are compared between mines, a significant degree of consistency is noted. The next phase of the study was aimed at differentiating the various dust sources associated with the shearer. To this end 'fly cuts' varying from 6 in. to 30 in. were closely monitored as were dust levels at operators' positions over the various segments of longwall cycle. These data indicated that the clearance ring of the shearer drum as a disproportionately heavy contributor to shearer dust make. A statistical analysis of the effect of shearer haulage speed on dust make revealed that high haulage speeds are associated with low specific dust make.

Jan 1, 1983

By F. E. Armstrong

This report describes development and application by the Bureau of Mines of techniques and instruments for using radioactive inert-gas tracers to determine flow paths through petroleum reservoirs that have natural fracture systems and for which water injection has been selected as the stimulative production method. A field test was made to prove the techniques and evaluate instrumentation. The feasibility of applying the techniques and instruments to the solution of reservoir problems in other stimulative methods of production also is discussed. Oil commonly is displaced from sandstone host rocks by the action of a driving force that causes the oil to move through interstices of the rock and into production wells. In addition to the requirements of oil being trapped within the sand pores and the presence of an effective displacement mechanism, the rock itself must have adequate permeability to permit flow of oil and other fluids.

Jan 1, 1961

By Laurance L. Oden

The Bureau of Mines is developing melting data for binary combinations of the alkaline earth fluorides and yttria to facilitate the formulation of slag compositions. The present report deals with the SrF2-Y2O3 system for which liquidus and solidus temperatures and solid solubilities were determined. The information is presented as the phase diagram. The phase diagram was constructed from information obtained by ceramogra¬phy, X-ray diffraction, thermal analysis, and electron probe microanalysis of small specimens encapsulated in platinum-20 percent rhodium or molybdenum ampoules. The data indicate a simple eutectic system with limited terminal solid solubilities. The eutectic temperature is 1,457°±5° C, and the eutectic composition is 4±1 mole-pct Y203. Strontium fluoride containing up to 2 wt-pct 0 2 was studied to determine the effects of oxygen contamination. Oxygen levels in excess of 0.2 wt-pct resulted in eutectic formation between SrF2 and SrO. The eutectic composition is between 0.2 and 0.7 wt-pct 02, and the eutectic temperature is 1,447°±5° C. No intermediate oxyfluoride phases were detected.

Jan 1, 1974

By Jan C. Still

The Haines-Klukwan-Porcupine subarea of the Juneau Mining District (JMD) is located in the northern portion of the JMD and consists of the land between the Alaska-British Columbia boundary, the Chilkoot Valley, Glacier Bay National Park boundary, and extending south to the Davidson Glacier and the Chilkat Peninsula and Islands (fig A-I). This area was studied as part of the larger JMD study in a cooperative effort between the Alaska Division of Geological and Geophysical Surveys (ADGGS) and the Bureau during 1985 to 1988. Prior to this, during 1984, the ADGGS and the Bureau cooperated in a study of the Porcupine mining area and during 1981 to 1983 conducted separate studies in the area. Field work was conducted by foot, boat, truck, and helicopter. Figure A-I shows the Haines-Klukwan-Porcupine sub-area and shows the areas covered by previous Bureau and ADGGS studies. PHYSIOGRAPHY AND CLIMATE The physiography of the subarea ranges from gentle to rugged. Glaciers formed the major features in the sub-area and left "U" shaped steep walled valleys and rugged mountains. The Chilkat, Chilkoot, Klehini, Tsirku, and Takhin are the major rivers in the subarea. The higher mountains are glacier clad and some valleys still harbor glaciers that reach the valley floors. Lush forests and dense brush predominate up to timberline at about the 2,000-foot elevation. Low point in the subarea is at sea level in the area around Haines while the high point is 7,434 feet at: Mount Henry Clay in the Porcupine mining area.

Jan 1, 2012

By Gregory J. Chekan

The U.S. Bureau of Mines is investigating longwall panel and gate road layouts to increase coal recovery and reduce multiple-seam interactive problems. This report presents design practices for longwall mining multiple seams to provide mine planners and operators with practical guidelines for designing productive longwall mines. Key aspects of mine design that control longwall interactions are examined, including sequencing of seams, design of gate road pillars, and orientation of gate roads and longwall panels. Theories that describe stress transfer between multiple scams and the mechanics of interaction are addressed in relation to geology. Common longwall designs were further investigated using a boundary element model, MULSIM/NL. The model provided insight into relative stress transfer and distribution that occurs between longwall operations in multiple seams. Findings from the model show that (1) a longwall panel should be mined from the gob to the solid coal of an overlying mine, because the stress concentrations are lower; the approach angle should be kept under 30°; and (2) when mining in descending order, superpositioning gate roads usually produces the worst stress condition. To prevent this, the overlying isolated gate roads should be positioned from the centerline toward the headgate side of the underlying panel.

Jan 1, 1993

By W. J. Campbell

This report by the Federal Bureau of Mines Particulate Mineralogy Unit recommends mineralogical definitions and identification-characterization concepts for selected silicate minerals and their asbestiform varieties. Precise definitions acceptable to mineral analysts, regulatory personnel, and medical scientists are essential because of the present lack of conformity in terminology concerned with measuring and controlling asbestiform particulates and their related health effects. Because of the complexity and variability of crystal morphology in different mineral groups, the descriptive terms are generally explained by illustration rather than by numerical values. Applications and limitations of several analytical techniques for particulate identification and characterization are discussed.

Jan 1, 1977

By Mark K. Larson

Researchers at the U.S. Bureau of Mines have developed a FORTRAN computer program that can calculate stress states from overcoring measurements obtained from hollow inclusion cells, triaxial cells, strain gauges installed on the wall of a bored raise, doorstopper gauges, borehole deformation gauges, or a combination of any of these gauges. Such stress states are calculated with reference to global and principal coordinate systems. The background of the development of the program, its capabilities, and its special features, as well as the input required, are described in this report. Sample output is also shown in appendix C. Difficulties associated with numerical calculations of principal stresses and directions are pointed out. Threshold values for detecting these problems are reported; these values may be changed by the user as desired. Several test problems were set up to verify the computer program and were successfully solved.

Jan 1, 1992

By J. B. Zadra

The use of activated carbon for extracting gold and silver from pregnant cyanide solution and pulp has been investigated many times. The primary advantage of this use of activated carbon is that .the dissolved values can be recovered from slimy ore pulps or from slime portions of ore without settling and thickening or filtering. The loaded carbon is removed from the barren pulp, and the pulp can then be discarded. Activated carbon has been used recently in treating gold ores containing very little soluble silver. When the carbon was loaded with a suitable amount of gold, the silver load was negligible. The remaining problems concerned the removal of the gold from the carbon, the recovery of the gold as bullion, and the reuse of the unloaded carbon. As described in a recent report, a method that solved these problems was developed. The gold-laden carbon was leached with caustic sodium sulfide solution and the gold simultaneously recovered by electrolysis. Both the carbon and the spent solution can be reused. That process was applicable to gold-laden carbon only. It was not applicable to carbon carrying silver, because sodium sulfide does not leach silver from carbon but "fixes" it. It has been necessary, therefore, to develop a modified process for the removal or desorption of both gold and silver from loaded carbon. This modi¬fied process permits the use of activated carbon for extracting both gold and silver from gold ores carrying enough silver to have economical interest or in which silver may be the predominating value.

Jan 1, 1952