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Founded in 1994 through a joint effort between Underwriters Laboratories Inc. (UL), the U.S. Consumer Product Safety Commission (CPSC) and the National Electrical Manufacturers Association (NEMA), the Electrical Safety Foundation International (ESFI) is North America?s only non-profit organization dedicated exclusively to promoting electrical safety in the home, school and workplace. ESFI is a 501(c)(3) organization funded by electrical manufacturers and distributors, independent testing laboratories, utilities, safety and consumer groups, and trade and labor associations. ESFI sponsors National Electrical Safety Month each May, and engages in public education campaigns and proactive media relations to help reduce property damage, personal injury and death due to electrical accidents. The Foundation does not engage in code or standard writing or lobbying and does not solicit individuals.

Jan 1, 2004

By Homer J. Ballinger

The Rex mine is one of several zinc deposits in Ozark and Howell Counties, Mo. It is the second of these deposits investigated by the Bureau of Mines in an effort to demonstrate reserves of sulfide ore underlying the shallow carbonate ores from which the district's major production has come. The initial investigation was made during 1945-46 on the Alice mine, Ozark County, Mo.21 The investigation reported herein was conducted during 1947. The Rex open pit is about 250 feet long, 100 feet wide, and about 25 feet deep (average). Three caved shafts are evident in the bottom of the pit, but the extent of the workings from these shafts is not known. The Bureau of Mines drilled five churn-drill holes in and around the Rex pit to test the grade and the vertical and lateral extent of the deposit. Two of the holes indicate notable zinc mineralization ranging from less than 1 to more than 10 percent metallic zinc, but largely in the oxidized condition.

Jan 1, 1948

By W. W. Graff

This paper describing the mining practices at Mine, No. 4 on the Marquette range, Michigan, is one of a series of articles on mining methods and practices in various mining districts in the United States. Mire No. 4 is located in the Swanzy district, in the southern end of the Marquette range, about 3 miles from Gwinn, Mich. The Swanzy district is an isolated ore-bearing formation, and Mine No. 4 is at the extreme southeastern end.

Jan 1, 1930

By Lloyd A. Morley, Robert Stefanko

1 Abaibanel, S , "Deflection of Confining Walls by Explosive Loads," Israel Jour. Technology, vol. 4, n. 1, Feb 1966. 2 Albertoni, S and others, "Numerical Computation Methods for Implosion Processes," EURATOM Proc. of the Conf. on Megagauss Magnetic Field Generation by Explosives and Related Experiments, Milan (Italy), July, 1966. 3 Alexander, S. J , and Hambly, E. C., "Design of Structures to Withstand Gaseous Explosions," Concrete, vol. 4, n 2, Feb. and March, 1970. 4 Anonymous (Belgium Institute of Extractive Industries), "Report for 1968 (covering approved equipment for Belgiums gassy coal mines)," (in French and Flemish), Amales des Mines de Belgigue, n. 6, June, 1969. 5. Anonymous (Ghent Univ., Belgium), "The Welding of Very Thick Steels. Margin of Uncertainty of the Robertson Test," EURATOM Contract 042-61-9-RDB, May 20, 1965. 6. Anonymous, "Inportance of the Nature and Size of Weld Defects with Regard to the Mechanical Strength of Pressure Vessels, (in Flemish), A. Sys. Rev. Soudure, vol. 27, n. 3, 1971. 7. Anonymous (Raentgen Technische Dienst N V., Rotterdam), "Non¬Destructive Welding," Quarterly Report No 13, EURAEC - 1342, March 30, 1965. 8. Anonymous (Staff, USBM Safety Research Center), "Research and Technologic Work on Explosives, Explosions, and Flames: Fiscal year 1969," USBM IC8492, 1970. 9. Anonymous, "Symposium on Flameproofing Intrinsic Safety and Other Safeguards in Electrical Instrument Practice, April 27, 1962," IEEE Conf. Report Ser. 3, 1963. 10. Anonymous, "Unfired Pressure Vessels," ASME Pressure Vessel Code, Sec. 8, 1965. 11. Anonymous, "Unusual Pressure Relief Devices," Industrial and Engineering Chemistry, vol 54, n. 1, Jan., 1962. 12. Archer, G. L., "Design to Avoid Brittle Fracture in Welded Structures," Paper No. 4, Improving Welded Prod Design, vol. 1, Welding Inst., Cambridge, England, 1971. 13. Bailey, F. C., "Buckling and Failure Strength of Plating Panels Loaded in Shear," Final Report NASA Contract NObs-72290, Lessels and Assoc., Inc., Waltham, Mass., Sept. 20, 1963.

Jan 1, 1974

Only limited work has been reported in the literature about the use of latex in soil. Unisol 91 2,3 (a 9:l oil-latex emulsion made b International Synthetic Rubber Company) and Phil1ips Petroset4 geotechnic emulsions are surface soil stabilizers which penetrate a maximum of two inches, but do not reduce permeability. Diamond Alkali 5 found that styrene-butadiene rubber latex as a one percent latex-soil mixture reduced permeability to 0.7 from 21 feet per year under a head of twenty feet of brine. We have found no literature reference for use of latex as sealant at depth in the soil, although asphalt has been applied at depth using civil engineering methods6,7. Most of the materials investigated as soil sealants in the present work were latexes, although some studies were also conducted with a variety of inorganic and organic chemicals. Of the latexes tested, most were rubber but a few were plastic, e.g. polyvinyl chloride. Sealants examined in this investigation are listed individually in Table I with supplier, code number, and other pertinent information. The materials consisted of the following general classes with additional details as indicated: 1.Anionic latexes: a. styrene-butadiene copolymers and terpolymers (SBR) b. butadiene-acrylonitrile copolymer (Paracrils®) c. polyvinyl chloride homopolymers and copolymers (WC) d. ethylene-propylene terpolymer e. vinyl acetate homopolymers and copolymers (VA) f. acrylics (acrylate copolymers) g. 2-chlorobutadiene homopolymer (chloroprene) (prepared specially as cationic material coagulated by soil). 2. Water Soluble polymers: a. polyvinyl ether b. methylcellulose c. polyethyleneimines d. polyacrylic acid homopolymer e. copolymers and terpolymers with acrylic acid types (water soluble as sodium or ammonium salts) f. alginates g. monomers (for polymerization in soil, e.g. acrylamide)

Jan 1, 1972

By M. R. Yenchek

The U.S. Bureau of Mines designed and constructed sensitive and coordination-free ground-fault relays (GFR's) for use on mine power systems. First, a list of GFR attributes for mine ac utilization applications was compiled. These practical guidelines specified design, construction, transient immunity, reliability, and operating criteria. The time-current characteristics of the ac and dc units, subsequently fabricated, were designed to be below the human electrocution threshold. The significant and highly variable capacitance of high-voltage distribution cables was found to preclude the sensing of ground currents in the milliampere range. However, the coordination-free system developed for high-voltage distribution should enhance safety by significantly decreasing response time to ground faults. Implementation of the sensitive GFR technology in the mining industry has the potential to eliminate the majority of injuries and nearly all the deaths resulting from contact with energized components.

Jan 1, 1990

By A. D. Garman

This digest of Brazilian mining law is based upon Decree 4265 of January 15 , 1921 , and its regulation , Decree 15,211 of December 28 , 1921. Unless otherwise stated , the references are to the latter exclusively , since it includes practically everything contained in the law itself . It should be borne in mind that these regulations do not necessarily apply to mines other than those on private and national land . Each State of the Union is free , in respect to State land , to regulate or interpret the national mining law , which is very general in its terms , as it sees fit . Whether such local regulations are anywhere in force with respect to the law of 1921 the bureau has not been informed . Article 64 of the Constitution indicates that only such portions of territory as are required for the defense of the frontiers , for fortifications , military constructions , and federal railways belong to the Union . Lessees of such lands , unless in debt to the Treasury , have preferential prospecting rights for one year ( art . 28 ) . This carries with it the right to work any mines discovered (Law , art . 12 ) .

Jul 1, 1930

By W. H. Oppelt

Two exploratory gasification tests of limited duration were made at Dorsten, Germany, with strongly coking Pittsburgh-bed coal in a fixed-bed pressure gasifier. To reduce the coking potential of the Arkwright coal, ash refuse from the gasification of Dorsten (Leopold) coal was added to pre-pare coal-ash mixtures which contained nominal 20 and 30 percent ash. Major adjustments in principal process variables at the beginning of the tests resulted in wide fluctuations in the rate of gas production, gas offtake temperature, and carbon dioxide concentration in the gas. Because a higher steam-to-oxygen ratio was used in the tests than was customarily employed for routine operation, gas production was lower, and steam and oxygen consumption was higher. After operating conditions had been improved, the results of a 12~-hour-long test with addition of sufficient ash refuse to obtain a nominal 30 percent ash concentration indicated that operation is feasible with this coal mixture using a fixed-bed pressure gasifier equipped with a rotating coal distributor and stirrer.

Jan 1, 1966

By W. P. Yant

A previous report of the Bureau of Mines dealt with the toxicity of dichlorodifluoromethane, a new refrigerant that has a remarkably low toxicity. Continued research by the Frigidaire Corporation and toxicological experiments performed in the Laboratory of Applied Physiology of the University of Cincinnati revealed another organic fluoride, dichlorotetrafluoroethane, whose toxicity also appeared to be of a very low order and whose physical and chemical properties make it suitable for refrigeration purposes. In addition to low toxicity, safety in its use is further enhanced by its physical properties, which permit the design of equipment that operates at comparatively low pressures and hence mitigates the dangers and problems of leakage. The investigation described in this report was performed by the Bureau of Mines at the request and with the cooperation of the Frigidaire Corporation.

Jan 1, 1932

By R. R. Wells

For several years the Klukwan deposit near Haines, Alaska, has attracted interest as a potential source of iron. Limited field and laboratory investigation has indicated that the deposit contains a large amount of Iron that is recoverable as high-grade concentrate. This report summarizes the results of laboratory beneficiation testing of the Klukwan ore, as represented by six samples submitted to the Alaska Experiment Station of the Bureau of Mines, Juneau, Alaska, Iron is present in the ore as a fine-grained magnetite associated with a pyroxenite type basic rock.. Satisfactory magnetic-separation procedures were developed for the production of concentrates assaying more than 60 percent Fe and 2 to 4 percent Ti02. During the investigation many data were obtained and compiled, but for convenience and clarity data of secondary importance have been omitted or condensed; only the more pertinent test results are discussed in detail.

Jan 1, 1953

By J. J. Hoeppner

Accurate determination of moisture in coals of various ranks has long been a subject of intensive investigation. Excellent reviews of methods developed over many years are given by Brown (9)4/ and, with experimental comparisons, by Goodman, Gomez, and Parry (11). As pointed out in these and other writings, one of the principal difficulties in assigning absolute merit to one or another procedure is the multiplicity of conditions under which water may exist in coal and the difficulties involved in obtaining sharp separation and distinction between these classes. Gauger (10) states: Water recoverable from coal is obtained from the following sources: (1) Decomposition of organic molecules (sometimes called combined water), (2) surface adsorbed water, (3) capillary condensed water, (4) dissolved water, and (5) water of hydration of inorganic constituents of the coal.

Jan 1, 1956

By G. S. Baur, J. W. Montoya, S. R. Wilson

Beryllium occurs in the Honeycomb Hills area in volcanic tuff similar to the more extensive berylliferous tuff occurring 20 miles east at Spor Mountain , Juab County , Utah . Samples from the two areas have been mineralogically examined to ascertain whether they have similar characteristics . The Honeycomb Hills samples showed the presence of beta- Be ( OH ) 2 , as well as an amorphous berylliferous substance , whereas in the Spor Mountain tuff the beryllium- bearing minerals are hydrated bertrandite and berylliferous saponite .

Jan 1, 1964

By R. D. Leitch

"INTRODUCTION The character of mine drainage from areas of low pyritic coal3 and from average pyritic coal4 has been investigated, and to complete the study it seemed desirable to select a number of mines situated in high pyritic are as to determine whether or not this variation determines the relative acidity of drainage from mines operating in these characteristic coal fields. Advantage has been taken of some worked on in 1918 by Henry Leighton 5, then Professor of Economic Geology, University of Pittsburgh. He visited and has reported certain areas of high pyritic coal which we also visited during this study. Many of the mines were found to be idle in 1930 and a few were caved shut, apparently for several years. However, samples of the outflow from all mines visited were collected if possible and analyzed, and some general information was gathered for each mine. The map (fig. 1) shows the location of these areas as given by Leighton.ACKNOWLEDGMENTSThe information and assistance obtained from officials and others at the mines visited during this study are gratefully acknowledged, as well as the original suggestion from Dr. Glenn V. Brown of the State Sanitary Water Board who called attention to the desirability of such a study.Thanks are also especially due the coal laboratory of the United States Bureau of Mines, under the direction of H. M. Cooper, for the analyses and determination of sulphur forms in the large number of solid samples necessary to the work reported,This study has been carried on under the direction of R. R. Sayers, chief, health and safety branch, and W. P. Yant, supervising engineer, Pittsburgh Experiment Station, of the U. S. Bureau of Mines."

Jan 1, 1932

A complete list of permissible mining equipment, rescue apparatus and gas masks tested. Prior to Jan. 1, 1929, w s published in Bureau of mines Information Circular 60972. The present list includes practically all equipment tested and. approved by the Bureau, up to and including July 1, 1929. It covers electric air compressors, coal drills, mining machines, loading machines, conveyors, mine pumps, room hoists,, mine telephones, rock-dusting machines, switches, electric cap lamps, flame safety lamps, electric hand and trip lamps, flash lamps, methane indicators and detectors, blasting units, storage battery locomotives, tandem locomotives, power trucks, concrete mixers, self-contained oxygen breathing apparatus and gas masks. The system under which these devices were tested permits the manufacturer, after his equipment has passed certain tests prescribed by the Bureau of Mines, to mark his equipment with a seal showing hat it has been "approved" by the Bureau. These tests are designs to insure that the equipment has the minimum requirements for safety in use. The only object of the Bureau in making such tests and publishing lists of permissible equipment is to safeguard the lives of workers and to help lessen the hazards of mining.

Jan 1, 1929

By Albert J. Rambosek

The objective was to obtain qualitative information on (1 ) the stress field in a core stub at the bottom, or face , of a cored borehole and (2 ) whether , and at what distance , in terms of core diameters from the face of the borehole , relief of stresses in the core is complete . The photoelastic and brittle lacquer techniques of stress analysis were used to determine the pattern of stresses in two- dimensional models , simulating the bottom of a borehole with a projecting stub of core . The core was stress- free at 1-1 /2 core diameters or more from the face of the simulated borehole . The analyses of the isoclinic and isochromatic patterns in the core near the face of the borehole reveal why core occasionally breaks into thin plates , when core or stress - relief drilling is attempted in highly stressed rock masses , such as heavily loaded mine pillars . stub broke away from the bottom in a hydrostatically loaded artificial rock specimen in a manner indicating that core " wafering" can result from tensile stresses developed in the core when a coring bit penetrates the highly stressed rock mass .

Jan 1, 1964

To provide accurate navigation and control of continuous mining systems.

Jan 1, 1996

By T. I. Weston

This is one of a series of papers being prepared for and published by the United States Bureau of Mines, describing mining and milling methods and costs at crushed-stone plants throughout the United States. These papers are designed to disseminate technical information regarding the methods used. The cost tabulations represent operating expenditures only and not total production costs. It is recognized' tat publication of total production costs might in many instances cause embarrassment to individual producers, as well as to the industry as a whole. However, operating costs are essential to the technical discussion and study of the methods employed. The attention of the reader is specifically called to this differentiation in order that no mis-understanding of the scope of the cost tabulations shall ensue. ACKNOWLEDGMENTS The author wishes to acknowledge the assistance-of F. W. Horton, mining engineer, United States Bureau of Mines, in the preparation of this paper.

Jan 1, 1933

By THEO L. JOHNSTON

In preparing for war , Japan built an iron and steel industry that ranked high with other industrial nations . Deficient in raw materials for making iron and steel , it had to acquire the bulk of its iron ore and much of its coal and scrap iron from foreign sources . Steel manufacture, and fabrication , however , were reserved mostly for the Home Islands , where modern integrated plants produced the implements of war . The vulnerability of relying on imports during the war was recognized early, and steps were taken to exploit iron-ore deposits and develop treatment processes on the Home Islands in order to be as self - sufficient as possible . Although the industry had expanded considerably, the capacity of the large plants still was insufficient for military requirements, so other meth- ods of producing iron and steel were adopted, which in some ways illustrate the desperate effort made to supply the war machine. In developing the iron and steel industry, modern practices of other countries were studied and followed with modifications to suit Japanese con- Aitions. German and American technical ability and equipment played a large part in the program; however, the Japanese had competent furnace technologists capable of obtaining proper equipment performance. For the most part, the standard practice consisted of smelting iron ores in blast furnaces and then refining the pig iron to make steel in open-hearth furnaces. Electric furnaces played an important part, especially in the manu- facture of alloy steels. Various other methods yielded minor but significant production. Among the various other treatment processes used, the production of sponge iron in rotary kilns 'probably was the most important in producing melt- ing stock for steel making. Of special importance was the fact that sponge iron made from low-grade ores contained critical metals, such as nickel and chromium, so that the results were more significant than was generally believed.'

Mar 1, 1948

By Kenneth L. Rubow, Virgil A. Marple, Bruce K. Cantrell

"In a cooperative study by the University of Minnesota and the U.S. Bureau of Mines, diesel exhaust and mineral dust concentrations have been measured for aerosols generated in the laboratory and in five underground coal mines. Three mines utilized diesel-powered haulage equipment and two used all-electric equipment. Two source apportionment techniques have been applied to differentiate between the mineral dust and diesel exhaust aerosol concentrations measured. The first technique, using a micro-orifice, uniform deposit impactor (MOUDI) for size selective sampling, is based on modeling aerosol size and the premise that the diesel exhaust portion of the aerosol is predominantly submicron and the mineral dust portion is mostly greater that one micrometer in size. The second technique, Chemical Mass Balance (CMB) modeling, was used to referee the analysis of diesel exhaust and mineral dust aerosol concentrations from the size selective sampling results.The MOUDI size distribution data were modeled to obtain parameters describing the fine and course fractions of the sampled aerosol and to estimate the contributions to each mode from both mineral dust and diesel exhaust aerosol sources. The results showed the size distribution of the mixed aerosols exhibited two definite modes with the minimum between the modes occurring at 0.8 µm. Less than 5 pct of the coal mine diesel aerosol was found in the coarse size fraction. CMB analysis confirms the original premise for using aerosol size to separate diesel exhaust and mineral dust aerosol during sampling.Based on the results from the size selective sampling, a personal diesel aerosol sampler has been developed for measuring diesel aerosol mass concentrations. Th.is sampler uses an inertial impactor to size separate the respirable aerosol at 0.8 µm. All material less than 0.8 µm is collected on an after filter for subsequent gravimetric analysis."

Jan 1, 1990

By Martin J. Gavin

During the recent study of lubricating oils carried on in the San Francisco laboratory of the United States Bureau of Mines, it became desirable to distill the oils used in the experimental work at pressures as low as 10 millimeters (mercury column) absolute. In the effort to Overcome difficulties and eliminate sources of error, certain changes were made in the apparatus for vacuum distillation used by the Bureau of Mines for crude petroleum.4 These changes were described in R.I. 2819, issued in July, 1927. Subsequent to the publication of R.I. 2819 several other changes have been made, and the present form of the apparatus for vacuum distillation of lubricating oils is described in this revision of R.I. 2819. These changes were found to give more accurate checks on duplicate distillations. The major part of the credit for the laboratory work which developed the changes in the apparatus and method revised herein is due to Boyd Guthrie, assistant petroleum chemist, and R. V. Higgins, junior chemist, o the San Francisco laboratory, United States Bureau of Mines. DESCRIPTION OF APPARATUS The distilling flask employed is essentially the Hempel flask as used by the United States Bureau of Mines for the analytical distillation of petroleum.5 he complete apparatus is shown in Figure 1. The fractionating column and exposed portion of the flask is wrapped with 4 inch asbestos rope and then surrounded by a cylindrical hood of 1/8 inch pliable asbestos sheet with a narrow air space between the wrapping and the cylindrical hood. This was found necessary to prevent any radiation or convection heat losses from the column, and resulted in obtaining a more even and constant fractionation by eliminating any dephlegmating action caused by temperature changes around the column.

Jan 1, 1930