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By Thomas H. Dubaniewicz

The National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory conducted a study of laser safety in potentially flammable environments. Researchers measured threshold igniting powers as a function of beam diameter for butane and propane-air mixtures by laser-heating targets placed on optical fiber tips using a 1064 nm laser. The minimum igniting powers for propane-air and butane-air were about 250 and 300 mW, respectively. Threshold igniting powers for propane-air were approximately proportional to beam diameter for beam diameters from 0.1 to 2.0 mm. Results suggest that relatively powerful beams may be used in these atmospheres without causing ignition, provided the beam diameter is controlled. Threshold ignition delay times using 91125 and 62.51 125 pm fibers were approximately proportional to the inverse square of the laser power. Ignition delays were about 45 ms or longer for laser powers up to 800 mW. Preproduction samples of a commercial optical fuse prevented ignitions under selected test conditions. A self-healing effect was observed for one sample. Comparisons are made with the results of other researchers. O 2006 Laser Institute of America. Key words: propane ignition, butane ignition, laser ignition, nonbeam hazards, fiber optic fuse

May 3, 2006

By E. P. Youngman

This paper is one of a series of digests of foreign mining legislation and court decisions that is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate-mines in various foreign countries. This interpretation of the mining laws of Greece was prepared from information furnished by Ralph B. Curren, American assistant commercial attache, Athens, in reply to a questionnaire of the United States Bureau of Mines, transmitted through the courtesy of the commercial laws division of the Bureau of Foreign and Domestic Commerce. INTRODUCTION In his report,3 Mr. Curren states that the source of his information was the Director of Mines of the Greek Ministry of National Economy and the Mining Code of Greece, which was, compiled from existing laws in 1929,4 and which has since been modified by several acts of Parliament.

Jan 1, 1932

By Henry W. Busch

Determination of the aldehyde content of Diesel-engine exhaust gas has proved rather cumbersome and unsatisfactory when carried out in its entirety in field investigations; therefore, studies were conducted with a view to developing methods by which samples might be collected in the field and trans-ported to the laboratory for analysis. Experience also indicated that aldehyde samples collected in water solution and then transported to the laboratory sometimes underwent serious changes in composition if several days elapsed between sampling and analysis. Polymerization of the aldehydes, which takes place readily in dilute aqueous solutions, may have been the cause of such changes. Because of these difficulties, experiments were conducted to find a suitable stabilizer or preservative for dilute aqueous solutions of the aldehydes that occur in Diesel-engine exhaust gas, so that in field studies a known volume of gaseous sample might be collected and brought into contact with water, and the resulting solution of aldehydes analyzed in the laboratory at some later time with reasonable certainty that the results would represent the composition of the original sample,

Jan 1, 1949

Lower costs associated with hands-on training in donning and using a CSE ,self-contained self-rescuer (SCSR). Background In June 1987, the Mine Safety and Heath Administration (MSHA) issued an Emergency Temporary Standard (ETS) requiring that all persons entering underground coal mines must be given bands-on SCSR training. The ETS will shortly be replaced by a new standard requiring this hands-on training. Bureau of Mines research has shown that the most effective means of delivering this training is to have the trainee go through a six-step training procedure while in a kneeling position. Once the miner has looped the neckstrap over his or her head, he or she completes the donning sequence in this order: 1) activate oxygen; 2) insert mouthpiece; 3) put on nose clips; 4) put on goggles; 5) adjust neck and waist straps; and 6) replace miner's cap and prepare to move out. This procedure is repeated until the miner demonstrates that he or she is proficient at the task.

Jan 1, 1988

By N. E. Hanna

[Testing explosives for safe use in coal miner ran boon an important factor in preventing mine explosions. In the United States, explosives that have been approved by the Bureau of Mines are called permissible explosives. A purvey of the history of coal mining since permissibility testing welt, instituted some 4 years ago shown that there is no record of a coal-mime explosion caused by permissible explosives when used in a manner prescribed by the Bureau. To maintain the appropriate standards of quality, the Bureau of Mines conducts a series of examinations and tenth on samples of explosives collected in the field. In what is considered the most crucial test, teat 1, the explosives An fired from a steel cannon into a gallery atmosphere containing a mixture of natural gas and air, In another important test, test 4, the explosives charge to fired into a mixture of natural gas, air, and coal diet. To satisfy the permissibility requirements, the explosive must undergo throe gallery teats without igniting gas or coal duet. Other tests also are required for permissibility, but they do not come within the scope of the present paper, which studies the factors affecting the incendivity of explosives when fired into methane, air, and/or coal-dust mixtures. It in believed that a better understanding of the factors will contribute to the development of safer explosives.]

Jan 1, 1954

By John L. Nieber

This information circular describes a computer program called VARSAT2D, a comprehensive unsaturated fluid flow simulator developed by the U.S. Bureau of Mines. VARSAT2D solves for either a vertical or horizontal, transient or steady-state solution in variably saturated, heterogeneous, anisotropic porous media using the Galerkin finite-element approach. Simplex triangular elements are used. Moisture retention characteristics are described by specifying either the Brooks and Corey, Brutsaert, or Van Genuchten power functions, with hysteresis described using the Maulem independent domain model. Boundary conditions may include any combination of time-varying seepage, pressure along solution domain, boundaries and/or at internal node points, unit hydraulic gradient at the lower boundary, and a uniform source and/or sink. This program should be a welcome addition for mining and environmental hydrologists, researchers, and engineers interested in modeling unsaturated fluid flow.

Jan 1, 1994

By Sidney Katell

An estimated capital investment of $76,499,800 will be required for a plant designed and built to produce 90 million standard cubic feet per day (std.c.f.d.) of synthetic pipeline gas through Lurgi gasification of bituminous char. This investment figure does not include the pretreatment plant, the cost of which is assumed to be reflected in the cost of the char fed to the gasification system. Shift conversion, C02 removal, and methanation are required after gasification in the Lurgi unit to make a gas suitable for pipeline transmission. Capital investment data are based upon equipment costs, January 1959. Based on a 90-percent or 330-day operating year, the operating cost before profit and Federal taxes with the char price as a variable will amount to the following: [ ]

Jan 1, 1959

By James E. Mauser

This report deals with the investigation of a continuous process for producing pure zirconium. It covers the construction, operation, and maintenance of the semicontinuous reactor. The report covers a study of test variables, such as reactor temperature and reluctant charge weights, and evaluates the results, such as billet metal hardness, residual billet salt content, and suitability of a purified billet as a consumable electrode for arc melting. The purpose of this project was to develop an inexpensive and continuous process for producing pure zirconium. The process developed, termed the semicontinuous reactor process, produced billets of compacted zirconium sponge. The metal was produced by reducing zirconium tetrachloride with sodium and magnesium beneath molten byproduct salt. Hydraulic rams at each end of a vertical reaction tube compacted the sponge and ejected it as a billet. These billets were purified by heat under vacuum to remove entrapped salt. The goal was to utilize the purified billet directly as a consumable electrode for arc melting.

Jan 1, 1961

By Chas. F. Jackson

During the current business depression the Bureau of Mines has received many inquiries concerning placer mining, the prospects for men of small means to make wages by small-scale placer operations, the locations of placer deposits in the United States, methods of working placers on a small scale, and allied subjects. It has therefore seemed desirable to prepare a circular covering, in nontechnical language, the principal questions which have boon referred to the Bureau of Mines for answer. There are a number of bureau publications dealing with placer mining, most of which are now out of print, but which may be consulted in the larger libraries. Other articles on placer mining nave appeared from time to time in the technical press and several good textbooks have been written on the subject. A partial bibliography of this literature appears at the end of this paper. A recent pamphlet published by the Idaho Bureau of Mines and Geology to assist the prospector and inexperienced small operator has received wide and favorable attention and is recommended as a useful reference. In the present paper no attempt will be made to cover the subject of placer mining in a comprehensive manner, but discussion will be confined to elementary questions of particular interest to persons of limited experience.

Jan 1, 1932

By George J. Conroy

To provide data as a basis for proposed acceptance standards and procedures covering permanent splices in trailing cables, the Bureau of Mines conducted testing programs on the flexure life in flat types W and G dc trailing cable splices and ground conductors. Primary reliance was placed on laboratory testing, although some cross comparisons were made at manufacturers' plants and mine operations Besides providing data for acceptance standards and procedures, results of the program should promote the general improvement of commercially available splice kits.

Jan 1, 1977

By J. F. McIlwain

Cobalt-base hardfacing alloys used for wear resistance consist almost entirely of metals largely imported into the United States. As part of an overall research program to help alleviate this foreign dependency, the Bureau of Mines has been investigating an iron-base alloy system as a potential replacement for cobalt-base alloys for some uses. To ascertain the melting ranges, thermal analyses were made of cast heats of alloys containing, in weight percent, 59-61 Fe, 16-19 Cr, 8-9 Ni, 1 Mn, 1 W, 1 Mo, 0.5 Cb, 0.6 Si, 0.3 C, and 0-12 stoichiometric TiB2. Powder alloys within this range of composition, prepared by mechanical alloying, were sized and applied to mild steel test coupons by nontrans-ferred-arc plasma spraying. The resulting thin coatings were >95 pet dense, with bond strengths of 35 MPa and hardness of 400 to 840 DPH. Abrasive and adhesive wear test data were compared to those of a plasma-sprayed cobalt-base alloy. A range of boride contents resulting in most promising properties was determined for further research.

Jan 1, 1985

By O. C. Blade

"INTRODUCTION This report on the properties of motor fuels sold through service stations in the United States is a continuation of a series of reports made in accordance with a cooperative agreement between the Coordinating Fuel Research (CFR) Com¬mittee of the Coordinating Research Council (CFC) 3/ and the Bureau of Mines of the United States Department of the Interior. The first of these reports presented data on motor gasolines sold during the winter of 1935-36. 4/ Further re¬ports were issued describing motor gasolines sold during the succeeding summers and winters to and including the summer of 1941.4/ No reports were made on motor gasolines sold during the winter of l941-42 and during the summer of 1942. However, starting with the winter of 1942-43, the semiannual reports were resumed. The present report presents analytical data for 3,011 samples, representing the products of 113 companies. Most of the samples represented in this report were obtained during July and August 1946. As in previous surveys the companies covered by the survey include both large and small suppliers. Conforming to former reports, the data cover three groups of samples - regular-price, premium-price, and third-grade gasolines.As the number of analyses submitted for samples of third-grade gasoline are not considered adequate to represent this type of motor fuel, data for the analyses have not been averaged, but the individual items are tabulated. The number of samples, items, and brands comprising each group is as follows: Regular-price, 1,585 samples, 311 items, and 99 -brands; premium-price, 1,422 samples, 280 items, and 94 brands; third-grade, 4 samples, 4 items, and 4 brands. The meaning of these terms as used in the survey is as follows:"

Dec 1, 1946

By Clayton M. Rumsey

No producing or developing mines nor known mineral resources are in the Lower Saline Valley Wilderness Study Area. The inactive Bonanza Prospect has low potential for copper-gold-silver resources. Stone and sand and gravel deposits in the WSA do not constitute mineral resources because transportation costs to major markets are prohibitive. INTRODUCTION The Lower Saline Valley Wilderness Study Area (WSA) covers 2,241 acres in southeast California adjacent to and west of Death Valley National Monument (fig. 1). Access to the WSA is by the Saline Valley gravel road 28 mi northerly from its junction with State Highway 190. The junction is about 35 mi southeast of Lone Pine, CA. The WSA is characterized by moderate to steep, sparsely-vegetated slopes; elevation ranges from about 1,800 ft to 3,560 ft.

Jan 1, 1984

By Michael S. Miller

During U.S. Bureau of mines mineral investigations, in 1981 and 1983, no mines, prospects, or mineral resources were identified in the Little Sand Spring Wilderness Study Area (WSA). Placer gold values in near-surface samples from alluvial fans within or near the WSA contained no more than 66 cents gold per cu yd, at $400 per troy ounce gold price. Sand and gravel and carbonate rocks occur in large quantities, but transportation costs to distant markets preclude their classification as resources. Nitrogen, lithium, clay, pumice, perlite, aragonite, and agate occurrences in the WSA are small or low-grade. The Silvia Mine, adjacent to the WSA contains gold-, silver-, copper-, and lead-bearing shear zones which strike toward the WSA. INTRODUCTION The Little Sand Spring WSA, encompassing 33,500 acres, is approximately 56 mi east of Big Pine, California, by paved and graded dirt roads (fl;. 1). Elevations range from 2,600 ft in Death Valley Wash to 5,600 ft along the California-Nevada boundary. The nearest permanent facilities are at Grapevine Ranger station and Scotty's Castle (Death Valley Ranch), about 9 and 11 mi, respectively, south in Death Valley National Monument.

Jan 1, 1983

By John D. Bradley

Stibnite is 76 miles east of Cascade, Idaho, which is 78 miles due north of Boise. The altitude at Stibnite is 6,500 feet, and between Cascade and Stibnite the Forest Service road crosses two summits - Big Creek at 6,800 feet and Warm Lake at 7,300 feet. The ownership of most of the Meadow Creek group of 190 claims, which is optioned by the Bradley Mining Co from the United Mercury Mines Co. may be traced back from their consolidation by the United Mercury Co. through ownership by prospectors and small promotional companies to the discovery of the Thunder Mountain district in 1900 by the Caswell brothers.

Jan 1, 1942

By H. M. Lawrence, E. Roca

"INTRODUCTION Of the phosphate rock deposits of the United States that are being exploited actively at present, the land-pebble area in Florida is the largest producer. In recent years the land-pebble district, in Polk and Hillsborough Counties, has produced about 80 per cent of the raw phosphate rock that has supplied the requirements of the several national industries based on this essential commodity.In the land-pebble deposits sizes finer than 16 to 22 mesh are below the commercial limit in phosphate content, and washing-plant practice has been directed to the recovery of the coarser material. Recently, more extensive control of the washery plan has resulted in the saving of additional amounts of phosphate, the loss of which had been considered unavoidable. However, strict requirements of the trade regarding the lowest acceptable grade of phosphate rock prevent the inclusion of more than a very small proportion of the low-grade phosphatic sands with the washery output of phosphate roe:. Further advances in practice resulting in larger recoveries of phosphate can only be effected by the application of processes that are based on other principles than merely a difference of particle size. Research is be conducted actively along these lines by the industry and by cooperating agencies.Flotation has been studied for several years by the International Agricultural Corporation and its allied company, the Phosphate Recovery Corporation. J. T. Burrows, vice-president of the International Agricultural Corporation, in a letter dated July 10, 1929, states:"

Aug 1, 1931

By A. D. Hahn

This report describes reconnaissance by the Federal Bureau of Mines of titanium-bearing sandstone in Kemper County, Miss. The purpose was to determine the ilmenite, rutile, and associated heavy-mineral content of black-sand-bearing Eocene deltaic formations" The investigation was part of a survey of titanium resources of the United States. Ilmenite (FeTi03), an iron-titanium oxide, is the major titanium-bearing mineral consumed in the titanium pigment industry. Rutile (Ti02), titanium oxide, is used mainly in producing welding-rod coatings and titanium metal. The fieldwork was conducted during the first half of November 1959. Seven holes, totaling 304 feet of bore, from which 64 samples of cuttings were taken, were drilled in the north-central part of the county; and two holes, totaling 172 feet of bore, from which 34 samples of cuttings were taken, were drilled in the southeastern part.

Jan 1, 1961

By S. C. Termes, P. E. Richardson, R. L. Wilfong

"The Bureau of Mines conducted research on the flocculation of various minerals with insoluble cross-linked starch xanthate (ISX) to determine its potential as a beneficiation technique for low-grade, highly disseminated ores and for selective desliming. Covellite, chalcocite, pyrite, pyrrhotite, chalcopyrite, bornite, sphalerite, galena, and molybdenite fines flocculate with ISX. Floc formation, floc size, and settling rate are dependent on pH, with the pH dependence differing for each mineral. Quartz is not flocculated by ISX. Experiments to obtain selective flocculation of sulfides from quartz were attempted. Good selectivity was only obtained for the bornite-quartz system. Post flocculation separations resulted in flocculated bornite in grades as high as 92 pct. Evidence is presented that the flocculation of many of the sulfide minerals with ISX may involve covalent bonding of the xanthate group to lattice metal site(s). INTRODUCTIONBecause of the increasing interest in selective flocculation as a beneficiation technique for low-grade, highly disseminated ores and for selective desliming, the Bureau of Mines has been investigating the flocculation behavior of several cross-linked starch derivatives containing chelating groups. This report dis cusses the flocculation of sulfide mineral fines by insoluble cross-linked starch xanthate (ISX).Polymeric materials such as ISX, which contain a chelating group of known re¬activity towards specific mineral surfaces, were first proposed by Slater, Clark, and Kitchener (1), 3 Kitchener (2), and Attia and Kitchener (3) as selective flocculants for mineral fines with particle aggregation possible through a bridging mechanism. ISX appeared to be attractive as a sulfide mineral flocculant because (1) alkyl xanthates are known to react selectively with sulfide minerals"

Jan 1, 1983

By Richard L. Rains

The Bureau of Mines made a study of mines and prospects of the Benton Range RARE II area (No. 5056), Mono County, California in October and November 1980. The study area is west of Owens Valley and 30 mi (40 km) north of Bishop, California. The mineral deposits were evaluated by examination of mines, prospects, and mining claims by the Bureau of Mines. Geological, geochemical, and geophysical studies were conducted by the Geological Survey. The principal mineral commodities of the Benton Range RARE II area are gold and silver but tungsten deposits may also extend into the area. Properties with resources are listed in table 1; their locations are shown on figure 1.

Jan 1, 1982

By J. M. Goris

Cable bolt supports are becoming an important ground control technique in underground mines in the United States and Canada. They show great versatility and are adaptable for use with many mining techniques, they have high load-carrying capacities, they can be installed in small areas with low roots, and they are cost effective. Investigators in a number of research institutes in North America have conducted studies to assess the material and support properties of cable bolts, evaluate their support capabilities under various mining conditions, and provide design criteria for using cable bolt supports as roof control systems under varying mining conditions. While conducting these studies, personnel have collected important information on the history, application, performance, and economics of these supports. This U.S. Bureau of Mines report documents this information so that ground control personnel unfamiliar with cable bolt supports can gain an understanding and appreciation of their use. A comprehensive bibliography of technical information on cable bolt supports was selected by the authors and is also presented.

Jan 1, 1994