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By J. M. Stuve

Provisional values for the heat of formation of europium trichloride and europium sesquioxide were determined by solution calorimetry utilizing europium metal of more than 99-percent purity. The resulting values for the heats of formation of Eu203 (cubic) and EuCls (hexagonal) were -386,970 ±l,200 cal/mole and -218,740 ±650 cal/mole, respectively, measured at 298.15° K.

Jan 1, 1965

By Jacob N. Frank

A factorially designed, hydraulic fragmentation experiment using a high-pressure water jet was conducted on concrete blocks. Three levels of pressure, standoff distance, and impact angle and two levels of traverse time and surface condition were used. Three variables were measured: depth of penetration, volume of material removed, and width of slot. Three stepwise linear regression equations were developed from the jet parameters and the physical properties of the concrete. The three basic equations, describing the significant jet parameters and physical properties, were developed into 15 predictor equations, five for each variable investigated. Direct regression equations were also developed for each variable investigated to show the result of increasing or decreasing each significant variable. Energy efficiencies were developed for the experiment and for each significant factorial variable.

Jan 1, 1971

Provide coal mine shafts/slopes with an optimum coal mine shaft fire and smoke protection system composed of reasonably-priced, reliable hardware. Approach Accident and injury data indicate that a relatively low percentage (5%) of underground coal mine fires occur in shafts or slopes. Nevertheless, shaft or slope fires are extremely serious because they block critical escape routes for miners. That also can happen when combustion products resulting from fires in other mine areas contaminate shahs and slopes. Seeking the optimum configuration for a shaft/slope fire and smoke protection systems, the Bureau of Mines gathered data on the performance of existing fire detection devices and signal telemetry systems In several mines, and analyzed the generic protection needs of the U.S. underground coal mining industry. The optimum system developed by the Bureau provided an adequate number of detectors, a wide area of coverage, and an extensive data acquisition, analysis, display, and storage capability. This system. recommended for fabrication and in-mine testing, consisted of a microcomputer-controlled master panel located in the test mine's slope hoist room, and four remote units. Two of the remote units were placed on the surface atop upcast ventilation shafts, a third was situated underground near the slope bottom, and a fourth was installed at the slope top in intake air.

Jan 1, 1986

Increase the safety of underground mine workers by minimizing hazards associated with rerailing mine cars after derailment. Background and Approach A serious operational problem in underground mines is the task of rerailing mine cars. Current rerailing practices are not only hazardous but are inefficient as well. Most methods involve pulling the derailed car back onto the track with a locomotive. This causes damage to the road bed and is not effective on curves or in situations where the car's wheels are too far from the rails. Jacks, wooden props, and pry bars are also used to raise or lower cars back onto their tracks but methods involving these tools require much strenous manual effort by mine workers, thus posing possible serious injuries. The problem is further compounded by the cramped, narrow confines of the underground mine environment which allows no space to permit use of cranes or other surface railroad rerailing techniques. The Bureau of Mines, aware of these problems, investigated improvements in current underground rerailing methods. Through a cooperative effort with Hoesch MFD, a system was designed and modified that can be easily carried into the mine by workers and quickly assembled at the derailment site. The system is hydraulically and pneumatically powered rather than reliant upon manual operation.

Jan 1, 1986

By M. M. Jones

A procedure for the spectrophotometric determination of uranium has been developed in support of minerals research being conducted by the Bureau of Mines. Uranium is separated from the sample by tributylphosphate extraction from acid solution containing added aluminum nitrate and (ethylene dinitrilo)-tetraacetic acid solutions. The colored uranium-dibenzoy1methane complex is developed in the organic phase by adding an ethanol solution of dibenzoylmethane buffered with triethanolamine. Absorbance is measured at 410 nanometers, and the response is linear up to at least 100 micrograms U30S in the aqueous aliquot taken for analysis. Aliquots containing as little as 8 micrograms U30S may be analyzed with relative errors no greater than ±5 percent. For aliquots containing at least 35 micrograms U308, relative standard deviation at the 95-percent confidence level is about ±2.2 percent. Appropriate procedures are given for analyzing a wide variety of samples.

Jan 1, 1980

By Robert H. Lambeth

The Madison RARE II study area has four prospects with identified resources. These are listed in table 1 and are described in the following text. A high potential for Sillimanite exists at the Placer Creek occurrence (fig. 1, no. 7) and potential for phosphate rack in all areas underlain by the Phosphoria Formation. Some prospects exhibit minor potential for copper, lead, zinc, silver, and gold in the southern portion and very minor potential in the northern portion. Deposits in the northern end also have low potential for rare earth, asbestiform anthophyllite, or kyanite group minerals (including sillimanite).

Jan 1, 1982

By Thomas J. Peters

The U.S. Bureau of Mines studied the 3,500-acre Winegar Hole study area, Idaho, a legislatively proposed (101st U.s. Congress) addition to the Winegar Hole Wilderness, Wyo.; it adjoins the western boundary of the Wilderness at the Idaho-Wyoming border, about 15 m; east of Ashton, Idaho. The study was part of an Idaho Land Assessment Program to provide minerals information for land-use decisions, and ensure domestic mineral supplies. The study area is an east-west elongated, wooded plateau south of Falls River. Although the area is covered with surficial glacial deposits, it is probably underlain by volcanic flows; light-colored and mafic flow rock were noted in sparse outcrop. No mines, prospects, mineralized areas, or mineral resources were found in the study area during a literature and field search. The only nearby prospects include geothermal and rock aggregate (volcanic cinder) sites, and several placer claims. Although the Winegar Hole study area lies within a region of potential geothermal resources, no evidence of geothermal activity was observed. Rock in the area does not split into flat slabs, which could be useful as dimension stone, and would require crushing to be used 8S aggregate. Alluvium (placer) samples contain less than SO.01 per cubic yard gold (at a $350 per oz price); alluvial deposits are too small to contain gold resources.

Jan 1, 1992

This Information Circular from the National Institute for Occupational Safety and Health (NIOSH) documents and supplements the information presented in a series of workshops held during 2002 and 2003. The primary intended audience consists of all who are involved in developing and conducting miners? training. According to the Mine Safety and Health Administration (MSHA), mine operators reported 240,000 full-time equivalent workers and independent contractors reported 42,000 full-time equivalent workers working on mine property during the year 2000. Unfortunately, these workers have a relatively high risk of suffering serious work-related injuries and illnesses. The mining industry has the highest rate of occupational fatalities among all U.S. industries. The fatality rate is 30 deaths per 100,000 workers compared to 4.6 for all private industry(Morbidity and Mortality Week Report, 2001; NIOSH, 2002).Compared to workers in other industries, miners also have a relatively high rate of nonfatal lost-time injuries, and their injuries tend to be more severe (Bureau of Labor Statistics, 1999). Many miners are also exposed to significant health hazards, including coal and silica dust, diesel exhaust, and noise. More than 1000 U.S. miners die of lung disease each year(NIOSH, 1999).

Jan 1, 2002

By J. W. Walkiewicz

One of the objectives of the Bureau of Mines is to develop substitution technology for scarce materials. In accordance with this goal, alloys containing lanthanum, cobalt, copper, and magnesium were investigated for fabrication of rare-earth-cobalt (RE-Co) permanent magnets. A complete substitution of lanthanum for samarium and a partial substitution of copper for cobalt was accomplished. Magnets of La-Co and La-Co-Cu-Mg alloys were fabricated by powder metallurgy techniques and evaluated. A maximum intrinsic coercivity of 23.2 kOe was obtained with a La-Co-Cu-Mg alloy. In comparison, maximum values of 9.3 kOe and 11.6 kOe were obtained with La-Co and La-Co-Cu alloys, respectively. The substitution of copper and magnesium for part of the cobalt resulted in a large increase of intrinsic coercivity, similar to the results of Bureau research with mischmetal-Co-Cu-Mg alloys. Unlike the mischmetal-Co-Cu-Mg magnets, the La-Co-Cu-Mg magnets showed signs of physical deterioration on exposure to air. The effects of fabrication parameters on the magnetic properties of the La-Co-Cu-Mg alloys were also determined.

Jan 1, 1982

By H. E. Powell

The selective recovery of nickel and zinc from a waste phosphate solution by solvent extraction was investigated by the Bureau of Mines as part of a broad program to recover valuable metals and compounds from industrial wastes, and to reduce the associated land and water pollution caused by dumping these wastes. The waste, which resulted from the phosphation of automboile bodies, yielded 99 percent of both the nickel and the zinc by extraction with dinonyl naphthalene sulfonic acid (DNSA) and di-2-ethylhexyl phosphoric acid (EHPA), respectively. Dilute sulfuric acid was used to recover the metals and regenerate the solvents.

Jan 1, 1970

By M. K. Larson, B. G. White

Researchers at the National Institute for Occupational Safety and Health (NIOSH) are investigating the causes and mechanisms of roof failure in underground mines. It is expected that a better understanding of these causes and mechanisms will lead to better layout and support designs that will help prevent accidents and fatalities associated with fall of ground. Two numerical experiments were conducted by NIOSH researchers using the Fast Lagrangian Analysis of Continua (FLAC) computer modeling program with a strain-softening continuum to simulate fracture zones. Two models, one of a round hole in a plate and one of a rectangular opening, were constructed and boundary conditions were applied to simulate far-field shear. The Particle Flow Code in Two Dimensions (PFC2D) computer program was used to look at the effects of far-field shear in generating fractures around an underground opening, but these models are preliminary until boundary conditions, strengths, and stiffnesses are matched to the FLAC models. Results showed that shear zones propagated from the opposite corners of openings in directions that appeared to be determined by opening shape and far-field stress. Tensile failures also formed and extended away from these shear zones. The consistent direction of shear deformation with respect to far-field shear provides a plausible explanation for preferred directions of shear as seen in geologic environments.

By R. H. Nafziger

As part of its program to help decrease the dependency of the United States on foreign imports of nonfuel minerals and to devise technology for the efficient and economic use of domestic resources, the Bureau of Mines smelted and sulfation-leached an ilmenite from northern Minnesota. The objective was to assess the feasibility of preparing chlorination-grade titanium feedstock. The concentrate was smelted with woodchips, coke, and soda ash in 91-kg-and 1-metric ton (mt)-capacity electric arc furnaces to form Ti-rich slag and commercial-grade pig iron. The slag contained from 67 to 77 wt pct titanium oxides and from 1.8 to 7.2 wt pct iron. Sulfation occurred in a 4.5-kg/h moving-bed reactor using S02-air mixtures at temperatures of 8000 to 8500 C to form soluble salts of the Ca, Mg, Mn,and Na impurities, which cause plugging of fluidized-bed chlorinators. Subsequently, the sulfated slag was leached in acid to remove the soluble sulfates. The final product from small-scale testing contained up to 95.5 wt pct Ti02, a minimum of 0.6 wt pct Fe, and a minimum total of 0.3 wt pct of the four impurities of interest. The final product meets charge specifications for chlorination. However, more large-scale testing is necessary.

Jan 1, 1987

By J. S. Tosh

An equilibrium study of the system potassium carbonate, potassium bicarbonate, carbon dioxide, and water has been conducted with solutions of 20-, 30-, and 40-percent equivalent potassium carboaate concentrations. These equilibrium data cover the operating range of the hot carbonate scrubbing system for removing carbon dioxide from gas mixtures. Such data are necessary to establish the limits of purification and are used to design absorption and regeneration towers. Values of K in the relationship K = (KHCO3)2/(K2CO3)PCO2 were determined for higher temperatures of 70" to 140° C. and greater concentrations, I 20 to 40 percent, than employed by previous investigators. For the 20- and 30-percent concentrations, K is constant at a given temperature; thus, once K has been determined the equilibrium pressure of carbon dioxide can be calculated for any conversion. Variation of & values with changing conversion was observed with the 40-percent solutions, so that equilibrium calculated pressures are less reliable from average K values.

Jan 1, 1959

By T. A. Gray, L. M. Crayne, P. Glogowski, Trevits. M. A.

Of the 19 major mine fire events (including thermal events) that have occurred in the last 6 years (2000-2005), it is estimated that remotely constructed mine seals could have been used at 65% of the events to control or suppress the fire. Underground observations of seals that have been remotely installed during mine fire events show that they often do not fully achieve mine roof-to-floor and rib-to-rib closure. Unfortunately, the inability to reliably close the mine void has limited or precluded the regular use of this technology. The National Institute for Occupational Safety and Health is conducting full-scale underground experiments at the Lake Lynn Experimental Mine to identify and remedy existing remote sealing technology shortcomings, to develop novel technologies, and to transfer the new or improved technologies to the mining industry. This paper will discuss the remote mine seal testing program and will provide the results of the in-mine experiments. Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health.

By George J. Conroy

This Bureau of Mines publication describes several fault locators and methods, including time domain reflectometers, a frequency domain reflectometer, tone generators, an infrared method, the Murray loop method, and high-voltage "click" methods. The Bureau of Mines has been conducting research into these methods for several years, to improve mine safety and facilitate production through rapid, safe location of trailing-cable faults. The problems encountered in practical applications are discussed, and schematic diagrams of several instruments fabricated by the Bureau are presented. Since no present single method of locating trailing-cable faults is universally applicable, a kit composed of several of the more promising fault locators is advisable.

Jan 1, 1978

By Isaac A. Zlochower, Kenneth L. Cashdollar

The Pittsburgh Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) conducted a study of the explosibility of various metals and other elemental dusts, with a focus on the experimental explosion temperatures. The data are useful for understanding the basics of dust cloud combustion, as well as for evaluating explosion hazards in the minerals and metals processing industries. The dusts studied included boron, carbon, magnesium, aluminum, silicon, sulfur, titanium, chromium, iron, nickel, copper, zinc, niobium, molybdenum, tin, hafnium, tantalum, tungsten, and lead. The dusts were chosen to cover a wide range of physical properties-from the more volatile materials such as magnesium, aluminum, sulfur, and zinc to the highly "refractory" elements such as carbon, niobium, molybdenum, tantalum, and tungsten. These flammability studies were conducted in a 20-L chamber, using strong pyrotechnic ignitors. A unique multiwavelength infrared pyrometer was used to measure the temperatures. For the elemental dusts studied, all ignited and burned as air-dispersed dust clouds except for nickel, copper, molybdenum, and lead. The measured maximum explosion temperatures ranged from "-1550K for tin and tungsten powders to "-2800K for aluminum, magnesium, and titanium powders. The measured temperatures are compared to the calculated, adiabatic flame temperatures.

By John S. Berber

Tar produced as a byproduct from low-temperature carbonization of coal contains only small amounts of valuable lower boiling tar acids but relatively high percentages of high-boiling tar acids. These high-boiling tar acids are characterized by a high degree of alkylation and can be converted into the lower boiling homologs by catalytic treatment to remove the alkyl groups or decrease their chain lengths.

Jan 1, 1965

By Douglas Pollock, John Organiscak

Water spray characteristics, including droplet size and velocity, airborne dust capture potential, and induced airflow quantity for various spray nozzle designs were evaluated to provide basic information for improving spray applications. Water droplet size and velocity characteristics were initially measured by a Phase Doppler Particle Analyzer (PDPA) for hollow cone, full cone, flat fan, and air atomized spray nozzles at similar operating parameters. Airflow inducement and dust capture experiments were also conducted under the same operating parameters to examine any salient features of the spray nozzle type, droplet characteristics, induced airflow, and airborne dust capture. Test results indicate that there are trade offs between airflow inducement and dust capture efficiency. A spray nozzle with a wider discharge angle was observed to induce more airflow, but at reduced dust capture efficiencies. Increasing spray nozzle fluid pressure(s) generally reduced water droplet sizes with concurrent increases in droplet velocity, airflow inducement, and airborne dust capture. Placing a three-sided barrier around the spray nozzles normally reduced spray air induction and increased dust capture efficiency. A direct relationship between airborne dust capture efficiency and spray input power normalized per unit of airflow induced was ob- served. This information can be utilized to improve the performance of water sprays for reducing airborne dust levels.

By M. E. Tyrrell

Work in this investigation was undertaken by the Bureau of Mines to demonstrate how waste glass might be utilized to lower the required firing temperature and firing time of structural clay products. Mixtures of waste glass and common clays were formed by stiff-mud extrusion and fired to the temperature required to produce a body having 6 to 7 percent absorption. Substitution of glass for one-half of the clay in a red body reduced the firing temperature 500° F, which made possible a 30-percent increase in production; in a tan body, the firing temperature was reduced 400° F, which made possible a 23-percent increase in production.

Jan 1, 1972

By Wilton Johnson

Native asphalt was produced by four companies in two States, Texas and Utah. Bituminous limestone, used primarily as a paving material for street and road repair, was produced by one firm. R. L. White Co., Dabney Quarry, Uvalde County, TX. Gilsonite, a solidified hydrocarbon found only in Utah and Colorado, was mined by three firms: American Gilsonite Co., a division of Chevron Resources Co. (a subsidiary of Standard Oil Co. of California); Ziegler Chemical and Mineral Corp.; and Hydrocarbon Mining Co. (a subsidiary of Oberon Oil Inc., a Utah corporation), from properties in Uintah County, UT. Gilsonite is used for a variety of purposes including automobile bodysealer, light-weight aggregate for cement used in oil well drilling, asphaltic building board, protective coverings, anticorrosive paints, and roofing compounds. Gilsonite production in 1985 declined 57% owing primarily to reduced oil well drilling activity. The value per ton was essentially unchanged.

Jan 1, 1987