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By W. K. Sawyer

In this Bureau of Mines investigation, one-and two-dimensional gas reservoir simulators were combined in such a manner that pressure distributions both in an induced vertical fracture and in the surrounding formation, could be determined as a function of time for any specified well production rate. The technique used consisted basically of the alternate ust of one-and two-dimensional algorithms for obtaining new pressure distributions in the fracture and in the reservoir, respectively. The pressures at adjacent reservoir and fracture nodes were used to calculate flow rates from the formation into the fracture, which provided source terms for both algorithms. The combination model developed provides the only known means of simultaneously simulating transient gas flow in a vertical fracture and the surrounding formation. Thus, the technique developed would be useful in locating wells in a gas storage field in that the effects of both fracture length and conductivity could be considered prior to drilling and fracturing operations. In addition, it will be helpful in analyzing pressure drawdown tests in a vertically fractured gas well since the entire test can be readily simulated for a wide range of reservoir and fracture properties.

Jan 1, 1974

By Henry G. Dorsett

Dust explosion data obtained in laboratory tests by the Bureau of Mines are presented for 73 chemical compounds and mixtures, 29 drugs, 27 dyes, and 46 pesticides. Information is given on ignition temperatures of cloud and layer, minimum igniting energy, minimum explosive concentration, percent of inert dust required to prevent flame propagation, limiting oxygen concentration in the atmosphere to prevent ignition, and pressures and rates of pressure rise at dust concentrations of 0.1, 0.2, 0.5, 1.0, and 2.0 ounces per cubic foot. Explosibility indexes are computed where data are available to permit comparison of the relative explosion hazard. Variations of explosibility parameters with chemical composition are discussed. General means for minimizing the dust explosion hazard are reviewed.

Jan 1, 1968

By W. E. Anable

The Bureau of Mines studied the purification of commercially available yttrium by melting it in a 100-kw electron-beam furnace. Button-scale melts were made to determine the ultimate purification that could be attained by melting yttrium at 1,733° to 1,770° C at low pressure (0.05 to 0.1 micron) for 1 to 120 minutes. In addition, numerous melts were made to study the effect of doping yttrium with carbon, 17 selected metallic additions, and 3 compounds. Except for nickel and zirconium, the metallic impurities in yttrium were lowered significantly on extended treatment; silicon was lowered only slightly. The nonmetallic impurities} oxygen, nitrogen, and carbon, were not lowered except on short exposures. In isolated instances, the oxygen content was lowered from 5,860 ppm to about 5,000 ppm. In most instances the carbon con-tent was lowered from 545 to about 220 ppm in 20 minutes and then increased again. It was concluded that yttrium cannot be purified by direct heating or by the doping technique employed.

Jan 1, 1965

By Todd M. Ruff

A training software package for new mine employees, called Miner Training Simulator (MTS), has been developed by researchers at the National Institute for Occupational Safety and Health. MTS is a computer-based tool that allows a trainee to enter a simulated mine and interact with his/her surroundings in order to learn basic mining concepts, safety procedures, mine layouts, and escape routes. The training simulator software and instructions for its use are described in this report. Also, each mine using the software will have different requirements with regard to safety training. To customize the simulator for these differences, an interpreted scripting language is used to define interactions between the trainee and the virtual mine and objects in it. The scripting language, called Tool Command Language, uses simple commands to control various actions in the simulation, such as sounds, safety messages, hazards, and movement of objects. The basics of the scripting language are described here, along with many examples and instructions for building a script for MTS.

Jan 6, 2001

By Edward A. Barrett, Lynn L. Rethi

Recent studies have shown that miners performing construction, maintenance, and repair (CMR) work activities in the conduct of their jobs incur from 39 to 65 percent of all reported injuries in the mining industry, The number is particularly high at surface aggregate operations; however, the problem exists at all mining locations and commodities. To address this issue, an interactive, (3-D) slides training exercise, Hazard Recognition Training Program for Construction. Maintenance and Repair Activities, was developed. The purpose of the exercise is to teach work& to recognize CMR hazards in the workplace and to deal with them using accepted safe work procedures. It was field tested using a total of 340 persons from surface mining operations in six states. The subjects were tested before and after the training intervention to determine if objectives of the instruction were achieved. Results indicated that 7 1 percent of the participants showed improvement in ink test scores. Following the posttest, subjects responded to a seven question Likert scale. These questions related to the validity of the exercise and the utility of the training program. More than 93 percent of the miners reported that they "learned something new from the training" and over 94% said they "would use these practices to work more safely".

By Edward Cogan

Equilibrium phase diagram studies of zirconium- rare earth metal alloys by the Bureau of Mines at its Albany Metallurgy Research Center prompted the development of a rapid gravimetric method for determining rare earths in zirconium in which the rare earths are absorbed from sulfuric acid solution of the alloy on a cation exchange resin . The sample in 10 percent H2SO4 is introduced into the column , the zirconium is eluted with 10 percent H2SO4 , and the rare earths are eluted with (NH4 )2SO4 solution and precipitated with NH4OH . A tracer technique was employed to determine the efficiency of the procedure . Y203 and europium 154 - 152 (Oak Ridge ) were added to 10 g of zirconium and taken through the entire procedure . Recovery averaged 97.6 percent on 0.002 μg europium in the rare earth fraction . Rare earths were determined in the range 0.10 to 90 percent .

Jan 1, 1964

By P. R. Bremner

In keeping with its mission to maximize mineral and metal recovery from domestic sources, the Bureau of Mines investigated a method to extract silver from tailings not amenable to cyanidation. Results of a laboratory study on the recovery of silver from cyanide tailings containing 1.7 ounces of silver per ton by leaching with an acidic ferrous chloride-sodium chloride solution are presented. The effects of reagent concentration and reaction time on the leaching of silver were investigated. A leaching solution containing 5 wt-pct NaCI, 2.5 wt-pct FeCI2, and 1.2 wt-pct HCI (for acidity) extracted 82 pct of the silver from the tailings during a 24-hour leach. The amount of HCI consumed during the leach was 46 pounds of HCI per ton of feed. Only 23 pct of the silver was extracted by conventional cyanidation. Ninety-nine percent of the silver was recovered from the pregnant solution by cementation onto iron powder.

Jan 1, 1982

By Stanton L. Tainter

"As an adjunct to its minerals-investigation program, the Bureau of Mines has developed a number of operating devices and techniques worthy of note. This paper, prepared under the supervision of J. H. Hedges, chief, Tucson Branch Mining Division, and under the general supervision of Lowell B. Moon, chief, Mining Division, reports upon certain methods devised to overcome difficulties encountered in cementing of diamond-drill holes at a Bureau of Mines project at Christmas, Gila County, Ariz.Pressure grouting was employed to recondition a caved hole it was desired to reopen and deepen. The hole, which had boon stopped 7 months previously at a depth of 488 feet, was caved below 449 feet in a contact zone of claylike, altered diorite and crumbly metamorphosed limestone. As other means of obtaining moderate pressure were not available, carbon dioxide gas, drawn from tank of liquid carbon dioxide through a pressure reducing and regulating valve, was used. The hole was reopened successfully with 12 grouting jobs.Another hole, where cawing from several water-bearing fractures between 202 and 232 feet gave trouble, was successfully cemented by the use of a grouting plug. An attempt to cement through the rods had failed, owing probably to agitation caused by water currents. Pressure grouting through the caning set above the cave could not be need, because water was forced up outside the casing when pressure was applied. The problem was solved by using a wooden plug 1-13/16 inches in diameter, which, when soaked in water, expanded to a tight fit in an AX hole. A hole was drilled through the plug, and a rubber flap valve was nailed to the lower end. In the upper end of the plug the hole was enlarged to fit loosely over an EX rod coupling finished smooth. The plug was lowered on the end of the drill rods to a point about 10 feet above the cave, where it was allowed to expand tightly to the hole. Cement grout was then pumped through the rods, and the rods were removed from the hole. After allowing time for the cement to set, the wooden plug was chopped out and drilling van resumed.Over 300 tests were made to determine the type of cement most suitable for use on the Christmas job, and the effect of cement-water ratio, temperature, and various admixtures on workability, setting time, and strength. The results of these tests, described in detail in the body of this report, indicate the desirability of thoroughly testing available cements when it is necessary to drill holes under difficult conditions that may cause failure.When it became desirable to reopen and deepen a caved drill hole, it was considered easiest to recondition the hole by pressure grouting, As other mans for obtaining moderate pressure were not available, a method utilizing carbon dioxide gas was employed. The hole was reconditioned successfully with 12 grouting jobs."

Nov 1, 1949

By G. T. Brow

An experimental method is described for testing diffusion of gases in crude oils at pressures and temperatures up to 3,000 psia and 200° F. A sampling technique was developed to withdraw by constant-pressure mercury displacement about 60 µl of oil from the diffusion cell through any of several 1/2-in vertically spaced capillary tubes and to trap about 4 µl of the oil in a specially designed microsampler. Oil trapped in the microsampler can be completely inserted in the sample inlet of a chromatograph. From analysis in a three-stage chromatograph (GLC), gas concentration in a sample is determined from the ratio of gas peak heights to area of peaks of reference components (hexanes or heptanes) in the oil. A diffusion coefficient is calculated from measured concentration profiles with known equations for diffusion in finite or semi-infinite systems, depending on whether the gas has or has not reached the end of the oil column. Results are given for a test of methane diffusing at 2,560 psia and 160° F in crude oil from the Weber Sandstone reservoir in the Rangely field, Colorado. A constant diffusion coefficient of 3.34 X 10-5 cm2 per sec was obtained which gives a good fit between calculated and experimental profiles determined at six times after start of diffusion. The maximum standard error of gas concentration determinations experienced with this method was ±0.88 ml per ml of gas-free oil.

Jan 1, 1970

By Duvall Wilbur I.

This is the second report to be presented on th application of stress analysis to underground Mining problems. In part I2/ of this investigation the stress distribution around single openings in unidirectional and hydrostatic stress fields was analyzed. Relationships between maximum stress concentration and size and shape of openings were determined by the photoelastic method. In most cases the results were verified by mathematical methods This report considers the stress distribution in pillars formed by two or more openings in a. unidirectional stress field. Relationships between stress concentrations and size and shape of pillars are developed. Applied to mining, results snow how estimates may be made of the stress distribution in pillars, what factors cause high local stresses, and how local stress concentrations may be reduced by proper design of mine openings. The photoelastic method was used, as in Part I, to study the stress distributions, and, whenever possible, the results were verified mathematically. A description of the photoelastic method and equipment is .given in Part I.

Jan 1, 1948

By E. L. Garton

An active list of permissible explosives was published in July, 1931, as part of United States Bureau of Mines Report of Investigations 3134, under the title of "Active List of Permissible Explosives and Blasting Devices Approved Prior to June 30, 1931." Changes in that list were authorized in August, September, October, November, and December, 1931, and January and March, 1932, as published in Reports of Investigations 3140, 3147, 3150, 3155, 3158, 3161, and 3163, respectively. By these changes the following explosives were added to the active Permissible list: Austin Red Diamond No. 1, L. F. Gel-Coalite W, L. F;" Austin Red Diamond No: 5. Gen-Gel No. 2. Black Diamond Nu-Gel No. 1 Genite C-1 Burton 1, L. F. Liberty No 4 Burton 2, L. F. Liberty No. 5 Burton 10, L. F. Peerless D Burton 12, L. F. Permigel 1, L. F. Burton F, L. F.

Jan 1, 1932

By A. T. Iannacchione, D. G. Puglio

This Bureau of Mines study covers 25 underground mines that were active in the Upper and Lower Freeport and Lower Kittanning coalbeds in 1976. The coal ranges from low to medium volatile in rank; its primary use is for steam generation. Seven mines emit more than 100,000 cfd of methane gas; those mines are the deepest and largest producers. The methane gas content of three core samples of the Lower Kittanning coalbed was estimated by the direct method. A sample from a depth of 320 feet contained 0.5 cu cm of gas per gram, at 620 feet there was 0.8 cu cm of gas per gram, and at 1,060 feet there was 11 cu cm of gas per gram. These results suggest that methane control problems will be encountered in the future as deeper coal is mined.

Jan 1, 1979

By John D. Sullivan

The present article is one of a series which is being prepared by the Southwest Experiment Station of the United States Bureau of Mines in cooperation with the Department of Mining and Metallurgy, University of Arizona, Tucson, Ariz., of papers dealing with factors involved in the leaching of copper ores. A knowledge of the time required to dissolve the various copper minerals present in ores, as well as of the consumption of leaching reagents is very desirable, because with the decrease of the Nation's total tonnage of sulphide ores increasing attention is being given to the recovery of copper by leaching methods from low-grade disseminated ore containing both oxidized and sulphide minerals. As leaching has already been applied with success and profit, this study was undertaken to determine certain fundamental characteristics that are applicable to all ores suitable for leaching.

Jan 1, 1929

By John D. Sullivan, Edward P. Barrett

The experimental work on the utilization of tin-plate scrap at the North- west experiment station of the U. S. Pireau of Mines in cooperation with College of Mines, University of Washington, necessitated the selection of a simple method for the determination of tin in the iron produced. Some of the standard methods for the determination of tin which were tried are given below: 1. Dissolving in acids and precipitating the tin as sulphide, igniting and weighing as Sn02. 2. Dissolving in aciis, reducing with nickel, cooling in an atmosphere of carbon dioxide, end titrating with standari iodine solution. 3. Dissolving in acids, precipitating the tin as sulphide, dissolving this sulphide in H3 and H2S04, heating until fumes of 503 are evolved, reducing with nickel or sheet lead, cooling in an atmosphere of carbon dioxide, ani titrating with a standard iodine solution.

Mar 1, 1923

By W. H. Ode, F. H. Gibson, W. A. Selvig

The great expansion of production of aluminum for war purposes has aroused some concern regarding the available supply of carbon suitable for making carbon electrodes required in the electrolytic aluminum process. Approximately three-quarters of a pound of carbon electrode is consumed for each pound of aluminum produced. 5 Because of its small amount of impurities and its suitable physical characteristics, calcined petroleum coke is the standard material used by the aluminum industry for making electrodes As it may be necessary to use some substitute materials, the possibility of using coke made from coal has been considered. Besides this possible use, information concerning the source of low-ash coals is of general interest. Specifications of the aluminum industry for calcined petroleum coke suitable for the manufacture of electrodes are very stringent in regard to allowable impurities. In one such specification the maximum allowable ash is 1.0 percent; the maximum allowable content of iron (as Fe) is 0.06 percent and that of silicon (as Si) is 0.08 percent; the maximum for cal- cium (as Ca) and for sodium (as Na) is 0.12 percent for each, but the two combined may not exceed 0.12 percent; maximum allowable sulfur is 2.0 per- cent. The presence of barium, nickel, chromium, manganese, cobalt, or vanadium is objectionable, and only extremely small amounts are allowed. In regard to physical properties, the coke is required to be so thoroughly calcined that it has a real density of at least 2.02.

Nov 1, 1943

By Philip W. Holland

The Bureau of Mines has developed a trace helium analyzer for deter-mining helium-4 in the parts-per-billion range. The instrument is used for analyzing pure gases, laboratory-prepared standards, and atmospher-ic samples. Accuracy at the 95-pct confidence level in the 50-to 20,000-ppb range is within ±2 ppb or ±0.4 pct, whichever is greater. The minimum detectable helium-4 concentration is calculated to be 5 ppb. The analyzer consists of a modified helium leak-detector mass spec-trometer, a laboratory-built sample inlet system, and a liquid-nitrogen-cooled charcoal trap. A programmable integrator and event-control module make automatic operation possible. The portability of the analyzer allows it to be used in the field.

Jan 1, 1984

By G. R. Friggens

A nuclear method for continuously monitoring the coalbed and ash levels and void formation in commercial-scale, fixed-bed, pressurized gas producers is proposed. Measurement of gamma ray transmission through the coalbed is the basis of the method. The coalbed level is monitored by detecting the trans-mission of gamma rays from a 1 to 2 Ci Co-60 source positioned on the outside wall of the vessel. Coal bridging or, alternatively, ash level is monitored by a 10 Ci Co-60 source at the center of the coalbed. Source activities and geometries are calculated for a 12-foot-ID producer designed to operate at 350 psi. Source capsule and detector specifications and operational safety are also discussed.

Jan 1, 1973

By H. B. Carroll

The Bureau of Mines investigated the adaptability of the Meteorology Research Inc.2 (MRI) nephelometer and the Sinclair-Phoenix smoke meter for use in routine, analytical, smog-chamber experiments and to compare their responses to aerosol during these experiments. Both instruments' sampling systems were modified--smaller size sample input systems were studied using the nephelometer and a secondary sample system was added to the smoke meter to allow measurement of Aitken or condensate nuclei. Both instruments were easily adapted for use with small smog chambers and both displayed good precision and sensitivity to aerosol. A correlation was shown to exist between the two instruments' responses to aerosol. This correlation makes it possible to report the Sinclair-Phoenix measurements in visibility and/or mass units if desired.

Jan 1, 1973

By E. G. King

Cerium and thorium sulfides have found use as crucible materials for melting certain radioactive metals. However, thermodynamic treatment of these sulfides has been hampered by lack of experimentally derived entropy values. This Bureau of Mines report describes heat-capacity measurements between 51° and 298° K, and entropy evaluations at 298.15° K, for cerium monosulfide (CeS), cerium sesquisulfide (Ce2S3), and thorium disulfide (THS2). The entropy values, with Literature results for the heats of formation, are used to obtain free energies of formation at 298.15°K. MATERIALS The samples used in this work were supplied by Prof, Leo Brewer of the Department of Chemistry, University of California. The methods of preparation and some of the physical and chemical properties of these sulfides were given by Eastman and coworkers.3 4/ Chemical analyses, conducted in our laboratory, gave the following results:

Jan 1, 1959

By J. J. Cummins

Green River oil shale previously extracted by benzene was heated at 150°, 200°, 250°, 300°, and 350° C for 0.5 to 360 days to determine the rate at which kerogen degrades to thermal products, the types of thermal products formed, and the effect of prolonged low-temperature heating (preheating) upon subsequent assay yields. Thermal decomposition of kerogen at 150° to 350° C is treated as a first-order reaction. The specific reaction rate for kerogen decomposition increases from 2.2 X 10-4 per day at 150° C to 2.0 X 10-1 per day at 350° C. The calculated kerogen activation energy is 19 kcal. Variations in the rate of formation of individual type components of the pyrolytic products were found. Carbon balances show an increase in the amount of kerogen converted to bitumen and oil (from assay of preheated oil shale) as the temperature of preheating increased from 150° to 350° C. Total product from shale preheated at temperatures of 150° and 200° C gave less than 100 percent of Fischer assay yields while the total products from shale preheated at temperatures of 250° to 350° C gave greater than 100 percent of Fischer assay yields.

Jan 1, 1972