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By Jack E. Fraley

Poor lubrication reduces the life of wire hoist ropes when they are used in corrosive environments. Although lubricants are added to ropes during the manufacturing process, these lubricants can deteriorate during use, and it is often necessary to add more lubricant to both the interior and exterior of the rope while it is in service. The U.S. Bureau of Mines evaluated the effectiveness of synthetic lubricants, using electromagnetic nondestructive testing (NDT) to measure deterioration in ropes while they were in service. For nonpressurized lubricant applications, synthetic lubricants appear superior to petroleum-based lubricants in their ability to penetrate to the interior of a rope. Therefore, the synthetics offer better wear and corrosion protection.

Jan 1, 1990

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 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

By Michael J. Sapko, Samuel P. Harteis, Eric S. Weiss

The Pittsburgh Research Laboratory (PRL) of the National Institute for Occupational Safety and Health (NIOSH) recently conducted full-scale explosion experiments; these experiments evaluated the strength characteristics of various seal designs used for safely isolating worked-out areas in underground coal mines. Large-scale explosion tests were conducted within the multiple entry section of PRL’s Lake Lynn Experimental Mine (LLEM) employing the only currently accepted test method endorsed by the Mine Safety and Health Administration (MSHA) for seal design in American mines. These explosion tests are labor-intensive, expensive to conduct, and can interfere with other critical underground safety and health research programs conducted by NIOSH. Therefore, the PRL has developed an alternative seal evaluation method, based on a hydrostatic pressure loading concept, that can facilitate the in-situ testing of seals in an operating mine. Two chambers within LLEM and one within the Safety Research Coal Mine (SRCM) were used for hydrostatic pressure loading various seal designs. The results from tests in these chambers compare favorably with those from the large-scale explosion tests in the multiple entries. Preliminary size-scaling relationships for predicting the strength of standard seal designs as a function of entry size is also presented. In addition to testing seal designs at the required 20 psi static pressure level, the new facilities also allow for the determination of the seal’s ultimate failure pressure. This new approach shows promise as an alternative evaluation method for improving mine sealing technologies which, in turn, will enhance the safety of the underground personnel.

By F. N. Kissell

The Bureau of Mines has successfully used sulfur hexafluoride (SF6) as a tracer gas to measure mine air flows under conditions where conventional methods have failed. SF6 was employed experimentally to measure accurately recirculation of return into intake air caused by leakage through an old stoped area, to check for potential leakage from an adjacent mine, to trace 10,000 cfm of “lost” air from an intake airway, and to measure transit air time through uranium mines. It proved useful as a means of accurately measuring airflow volumes in airways of large cross section and very low flow velocity, and in determining the recirculation resulting from underground cooling plants.

Jan 1, 1974

By J. E. Emmerling

The Federal Bureau of Mines investigated dust suppression obtained with three different water-spray nozzle systems during underground continuous coal mining at the face. The nozzles were the "regular" nozzle normally used by the mine, and high-efficiency and low-efficiency nozzles selected on the basis of an airborne capture theory of respirable dust by spray drops. The high-efficiency nozzle used one-third less water than the others throughout the testing. Results depended on the type of cutting operation at the face. The sump-downshear operation appeared to involve a significant amount of capture of airborne respirable dust. The same amount of dust was measured when using the high-efficiency and regular nozzles. The dust levels when using the high-efficiency nozzle were about 20 pct less than those measured when using the low-efficiency nozzle. The sump-upshear operation seemed to involve a predominance of other aspects of dust suppression, such as impaction of spray drops onto the face. Compared with the downshear operation, there was a significant reduction in dust levels for a total face operation when using the regular nozzle; dust levels when using the regular nozzle were about 15 pct lower than those measured when using the high-efficiency nozzle.

Jan 1, 1975

By Laurance L. Oden

The Bureau of Mines studied three processes for preparing NaAl(OH)2C03) the intermediate compound which is calcined to produce alkalized alumina: (1) Mixing of Na2 C03 and of A12 (S04)3 solutions, (2) digestion of aluminum hydroxide in solutions of Na2C03 and NaHC03 at 90° C, and (3) addition of CO2 at 25° C to caustic solutions of aluminum to precipitate aluminum hydroxide followed by digestion at 90° C. The first process had the highest raw material consumption and washing requirements, and successful application of process 2 depended upon the availability of active aluminum hydroxide. Process 3 was the most effective, considering both process technology and raw material requirements. Procedures were also investigated for washing, filtering, drying, and calcining precipitates. Analytical methods included X-ray diffraction, atomic absorption spectroscopy, differential thermal analysis, and thermogravimetric analysis.

Jan 1, 1969

By Michael D. Fenton

The modest mineral industry of Afghanistan continued to suffer adversely from internal disorders that were essentially the result of the continued presence of elements of the armed forces of the U.S.S.R. Despite press reports near yearend intimating that the Soviets might reduce troop strength in Afghanistan, there were no indications of any significant numeric reductions. Indeed, there were clear demonstrations of heightened military actions along the Afghani-Pakistani border, including bombing raids on settlement sites for Afghanis within the territorial limits of Pakistan, actions hardly demonstrative of conditions indicative of Soviet withdrawal.

Jan 1, 1988

By Earl C. Lane

This is the second of a series of reports on a survey of petroleum products manufactured on the Pacific Coast from California crude oils. California crudes differ in many characteristics from the petroleum produced in other parts of the United States, and the claim has been made that some of the present federal Specifications for petroleum products tend to discriminate against California products. The purposes of the present survey are to determine what particular specification requirements California petroleum products characteristically fail to meet, how widely the products deviate from these requirements, and if possible to show whether the fault lies with the specifications or the products, or along what 'lines investigation to determine the question should proceed. The first report* of the series gave the physical and chemical properties of gasoline and mineral spirits made from California crudes. The present report deals with lubricating oils. Sixty-one samples of lubricating stocks and finished commercial products were generously donated by four of the large refining companies of California. Fifteen samples of automobile lubricating oils, made in California from California crudes, were purchased in the open market. Nine samples of lubricating oils mode from Gulf Coast crude were contributed for comparison by a company in Texas. The refining companies have continued the helpful and cordial cooperation shown by them in connection with the earlier work of the survey.

Jan 1, 1923

By Kevin Michael, David C. Byrne

In previous issue of Spectrum (October 1999, 16/4), a system of measuring the attenuation provided by insert-type hearing protectors was described, That report described experiences using the FitCheck (Michael & Associates, Inc.) system in a pilot project involving the steel industry during 1998.[ ]

By Eugene Baker, Joseph Cervik, Albert Sainato

In Europe, water infusion is used widely to reduce generation of respirable dust during mining. Its use in the United States is limited to a few plow operations in the Pocahontas No. 3 Coalbed. This Bureau of Mines report describes the technology for infusing water in to a longwall panel and reports the results of a recent demonstration in the Lower Sunnyside Coalbed that achieved dust reductions averaging 58 pct. Because water infusion increases moisture content of the coalbed, face air velocities in excess of 500 ft/min (2.5 m/s) are possible, further diluting dust levels before dust entrainment occurs. An economic analysis shows a 23-pct reduction in operating costs when coal production is increased by changing from unidirectional mining to bidirectional mining with water infusion.

Jan 1, 1983

By P. A. Bloom

Arsenic-containing flue dusts are currently being stockpiled by several nonferrous smelters in the United States. These stockpiles are a source of environmental concern since the dusts can be transported by wind and contain water-soluble arsenic. The stockpiles also represent an alternate source of metals. To provide a quality environment, the Bureau of Mines investigated a process to make environmentally acceptable the discard of arsenic obtained from the treatment of arsenical flue dust. The process includes (1) leaching arsenic from a lead smelter copper dross flue dust, (2) fixing arsenic as an insoluble compound, and (3) recovering other metal values. Overall results of acid-leaching tests on lead-smelter flue dusts showed that H2S04 dissolved 80 to 90 percent of the As, Zn, and Cd, and up to 86 percent of the In. Pb, Ag, and Au remain in the residue, which can be recycled to the smelter. Indium was recovered from the strong acid leach solution by solvent extraction; arsenic was fixed in a stable form by precipitation with Fe2(S04)3 and CaO or CaC03.

Jan 1, 1982

By B. W. Madsen

As part of a program to maintain an adequate supply of minerals and metals to meet national economic and strategic needs, the Bureau of Mines conducted research to determine the diffusion coefficients for ferric ions in synthetic copper leach solutions. Determination of ferric ion diffusion coefficients in typical dump leach solutions is necessary for predicting leaching rates of copper from large-scale leaching operations and for optimizing concentrations of ferric iron in solutions to maximize leaching efficiency. Derivative chronopotentiometry, an electroanalytical technique, was used to determine ferric ion diffusion coefficients. The diffusion coefficient decreased dramatically with increasing concentration of iron in solution. An empirical model was used to relate the ferric ion diffusion coefficient to the total amount of sulfate in solution. Measuring the diffusion coefficient dependence on temperature yielded an activation energy of 5.5 kcal/mole of ferric ion. Activity coefficients of ferric ions as a function of concentration were calculated from diffusion coefficient data.

Jan 1, 1981

By J. W. Paul, A. C. Fieldner

"In cooperation with the New York and New Jersey State Bridge and Tunnel Commissions, the Bureau of Mines has just completed the construction of an experimental tunnel in the Bureau's experimental mine at Bruceton, Pa., near Pittsburgh, Pa. The purpose of this tunnel is to make a final study of the ventilation problems arising in the adequate ventilation of vehicular tunnels for automobiles and trucks, especially the 9000-foot tubes that are being designed. to handle the traffic between New York City and New Jersey under the Hudson River.Chief engineer, Clifford M. Holland, of the Tunnel Commissions has shown that there are three principal problems involved in planning the ventilation of this tunnel, namely - (1) The amount and composition of exhaust gases from motor vehicles; (2) The dilution necessary to render these exhaust gases harmless; (3) Determination of coefficients of airflow and horse-power required in ducts, bends and openings.Composition of automobile exhaust gases.The answer to the first problem was obtained by making road tests on 101 automobiles and trucks at the Pittsburgh experiment station. These machines were taken from service without any previous adjustment so that the composition and amount of the exhaust gas may be taken as representative of actual operating conditions prevailing in the tunnel. A report covering the results of these tests was submitted to the chief engineer of the Tunnel Commissions, on November 1, 1920, and 411 be published in the report of the commissions. Several papers a have also been published in the technical journals summarizing the important results as regards tunnel ventilation and also with reference to gasoline losses in present-day motor car operation due to the general use of unnecessarily rich mixtures"

Oct 1, 1921

By D. J. MacDonald

The Bureau of Mines has carried out investigations on a method for producing zirconyl sulfate solution from zircon sand, comprising (1) reacting zircon sand with molten NaOH, (2) leaching the resultant fusion frit with water to remove sodium silicate and to convert sodium zircon-ate to hydrous zirconium oxide, and (3) leaching the hydrous zirconium oxide from unreacted sand with hot, dilute H2S04 to produce crude zirconyl sulfate solution. The following conditions were found to be suitable: reacting 0.6 kg of NaOH per kilogram of zircon sand for 10 min at 600° C; leaching the frit with 3 to 4 liters of water per kilogram of solids; leaching the residue with 5.1 liters of water and 1.25 liters of 98-pct H2S04 per kilogram of original solids for 10 min at 90° C; and filtering or decanting to recover unreacted zircon sand. A preliminary cost estimate is included.

Jan 1, 1982

By David A. Monaghan, Kenneth R. Maser, Adi R. Gurdar, D. Randolph Berry

APPENDIX A - PNEUMATIC TRANSPORT OF FLY ASH 1. Introduction Two types of pneumatic transport of fly ash are critical to the success of (1) Transport of fly ash from the fly ash truck to the entrance to the borehole. Depending on the surface topography, this may be horizontal, decential and ascential. (2) Vertical downflow of fly ash through the borehole. All fly ash trucks have limited pressure with which they can pump the fly ash. Thus, the pressure drop in the fly ash hose will define the maximum length for pumping and consequently the maximum distance that the fly ash truck can be parked from the auxiliary blower. The same relationships describe the flow of the dilute fly ash-air mixture produced by mixing with the auxiliary air from the blower and thus define the selection of the pipe diameter. These are im¬portant considerations in the proper selection of the location of the passages to be sealed and the type of surface preparation required. The flow characteristics of fly ash down the borehole determine the selection of the minimum borehole diameter and the blower pressure. This appendix presents theoretical analyses of these flow regimes and summarizes the limited experimental data obtained during the field tests at Grant Town, described in Section 8.4. The analysis for the borehole flow is presented first as it is of greater interest to the program. This is followed by a discussion of the horizontal flow.

Jan 1, 1973

By B. D. Hanson

The U.S. Bureau of Mines has developed an interactive computer program which enables the user to identify the effect of cutting system changes on relative dust generation and forces for continuous miner drums. The program simultaneously evaluates machine and coal seam parameters, and those parameters which the user can control. One or more of these parameters may be changed to determine their individual or collective effect on relative dust generation and cutting forces. The program is written in the BASIC programming language. A complete program listing is included along with user instructions and sample outputs.

Jan 1, 1989

By T. A. Sullivan

Research undertaken by the Bureau of Mines in 1938 has resulted in the development of titanium from a laboratory curiosity to a commercial metal. Along with processes for producing the metal, it was necessary for the Bureau to develop methods for analyzing the metal, raw materials, and intermediate products. Some of the methods developed have been published.3 4 5/ General Services Administration (GSA) was responsible for purchasing titanium metal under Defense Production Act contracts with commercial producers. GSA designated the Federal Bureau of Mines to analyze this metal and establish its compliance with Government specifications. A substantial quantity of tin was found in some of the samples analyzed, and in July 1957 tin was added to the list of impurity elements to be determined. The specifications limited the amount of tin in titanium sponge to a maximum of 0.10 percent. A program was immediately initiated to investigate methods and techniques for determining tin in the range of 0 to 1.0 percent. A method accurate at the 0.10 percent level was necessary, as this level was the critical range for acceptance or rejection of the metal.

Jan 1, 1960

By S. J. Hussey

A jig tailing with gold content ranging from 0.33 to 0.43 oz/ton was leached in weak cyanide solution with extractions of up to 97 pct in 24 hours. By countercurrent batch leaching studies and laboratory pilot plant operation, minus 10- plus 20-mesh and minus 6- plus 16-mesh coconut carbon were loaded to 700 oz/ton of Au. Minor silver in the ore reported in the carbon in amounts of up to 100 oz/ton. Gold adsorption rate data and an equilibrium adsorption curve for minus 10- plus 20-mesh carbon at ambient temperatures were developed and used in the successful application of a cascade design theory. The work was performed as a part of the overall Bureau of Mines research effort to help maintain an adequate domestic supply of metals by making improvements in mineral-processing technology.

Jan 1, 1979

By Theodore Christos

The Bureau of Mines sponsored an investigation of the thermal oxidative degradation characteristics of certain solvents and hydraulic fluids used in underground mining operations. The following halogenated solvents were studied in view of their usefulness and their flame retardant property: tetrachloroethylene, C12C = CC12; 1, 1, 2-trichloroethane, CIH2CCHC12: and trichloroethylene, C12C = CHC1. The hydraulic fluids studied were representative of five groups approved by the Mine Safety and Health Administration for underground operation, namely: glycol-water solutions, mineral oil-water emulsions, synthetics other than phosphate esters, synthetic phosphate esters, and mixtures of phosphate esters with mineral oils and other ingredients. It was observed that the partially halogenated solvents present a greater potential toxic hazard than the fully halogenated materials, due not only to the easy production of hydrogen chloride but also to their ease of oxidation leading to the formation of phosgene and carbon monoxide. The pure phosphate esters exhibited the best thermal oxidative stability of the five groups of hydraulic fluids tested. A fluid containing phosphate esters mixed with mineral oils and other unidentified ingredients appeared to be the most hazardous On the basis that it produced very toxic acrolein and phosphine.

Jan 1, 1980