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By R. O. Pynnonen

Tunnel-driving is recognized as a hazardous occupation; adequate support of roof and sides for preventing accidents from falling material is usually one of the most important safety problems. Where extraordinary conditions of sand and water are found, this problem becomes even more difficult. Tunneling at the Tioga No.2 mine was stopped when a 22-foot bed of water-saturated, fine gray sand was encountered. The tunnel, designed to house an ore-conveyor belt, was being driven from both ends. Driving was extremely difficult at both the upper and lower faces when the sand horizon was reached. A distance of 178 feet remained between the faces. Heavy pressures deformed the steel-supporting rings at the upper face, and there was an inrush of mud and sand at the lower face.

Jan 1, 1958

By Donald R. Irving

THIS CHAPTER is new to the Minerals Yearbook and will appear regularly hereafter. Its purpose is to present statistics that reflect technologic trends in the minerals and metals industries (except fuels). Much useful information has been collected annually through the Bureau of Mines mineral commodity and employment and injuries canvasses. However, these data must be supplemented by further data to permit evaluation of the type, direction, and rate of technologic change, which are vitally important in long-term mineral planning. In addition to, and fully as important as, expanding the available data is the need to ascertain that the various items collected are obtained from identical reporting units, to enable direct comparisons to be made.

Jan 1, 1960

By E. G. Valdez

Iron foundries that melt automobile scrap produce flue dusts averaging about 32 percent zinc and 6 percent lead. Some is sold to smelters, but because of the meager return and difficulty in handling, most of the dust is discarded. As part of the Bureau of Mines program to find uses for mineral wastes, research was initiated to develop an economical process to recover zinc and lead from the flue dust. Research encompassed the extraction of zinc and lead by fuming, leaching, and agglomeration. Controlled vacuum fuming of zinc to produce Prime Western zinc and a lead-rich residue was the most effective method for treating the dust. This process involved two distillations, or fumings, with carbon and methane as reductants, and resulted in recovery of 91.4 percent of the zinc in a Prime Western grade product, and 98 percent of the lead. Hydrometallurgical techniques involved several leaching methods, but the simultaneous extraction of iron, manganese, and copper resulted in contamination of the solution and made the zinc recovery processes too complicated. Agglomeration was done by pelletizing or briquetting the dust for possible use as feed to a zinc smelter.

Jan 1, 1975

As a basis for recommendation and for instruction of bureau engineers the considered opinion of the bureau is expressed in "decisions" of its Mine Safety Board, approved by the Director. Ten of these decisions were discussed, in Information Circular 6091.3 Decision No. 11, approved by Scott Turner, Director, on February 28, 1929, is as follows: "In the interest of safety, the Bureau of Mines, Department of. Commerce, recommends that in coal mines, haulage and (or) hoisting be kept in intake air as far as possible." As in the case of previous mine-safety decisions, the subject matter covered by this decision has frequently come to the attention of the Bureau of Mines through the reports of its mining engineers on explosion disasters and in accident-hazard investigations.

Jan 1, 1929

By L. B. Pankratz

The Bureau of Mines conducted heat-content measurements above 298.15° K for dehydrated analcite (NaAISi2O6) to 1,000°K, kaliophilite (KA1Si04) to 1,800° K, and leucite (KAlSi206) to 1,800° K. Heat content and entropy increments were tabulated, and the heat content data, were given in equation form. A first order transition was noted for kaliophilite near 810° K with a heat absorption of 160 cal/mole. Leucite had a second order transition which became complete near 955° K. In this transition a crystal change occurred from tetragonal (low-temperature form) to cubic (high-temperature form).

Jan 1, 1968

By Willard L. Hunter

The separation of tantalum and columbium by solvent extraction was under-taken as part of the Bureau of Mines research program to improve methods for extracting, separating, and reducing these elements to metal. The diethyl ketone aqueous HCl-HF system was one of several systems studied to determine the effect of metal and acid concentrations in aqueous solutions upon the transfer of tantalum and columbium into selected ketones. The tantalum-columbium oxide mixture used in this investigation was obtained by chemical extraction from Geomines slag. The investigation showed that tantalum 99.4 percent pure and columbium 97.2 percent pure can be produced by the selective transfer of tantalum into diethyl ketone from a solution of 2-N HF and 1-N HC1. The relatively low acid concentration necessary for tantalum transfer and the excellent selectivity of the system recommend its use for the separation of tantalum and columbium.

Jan 1, 1961

By Jami M. Girard

INTRODUCTION Slope stability accidents are one of the leading causes of fatalities at U.S. surface mining operations. The Spokane Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) is currently conducting research to reduce the fatalities associated with slope failures and other unexpected failures of ground. The purpose of this paper is to introduce various warning signs of slope instability so operators are better able to recognize hazards. The most common slope monitoring equipment and practical methods of installation are discussed as well as the limitations of these systems. CONSEQUENCES OF SLOPE FAILURES Unexpected movement of ground causes the potential to endanger lives, demolish equipment, or destroy property. Between 1995 and 2001 (2nd quarter), 34 fatalities were caused by ground instability. This accounts for approximately 15% of all surface mine fatalities (Figure 1). These figures include fatalities classified by the Mine Safety and Health Administration (MSHA) as “fall of face or highwall,” “powered haulage,” “equipment,” and other MSHA accident categories, where the primary cause of the accident was unanticipated movement of the ground. This includes fatalities resulting from bench and highwall failures, rock falls, waste dump and stockpile failures, and the collapse of unknown underground workings. [ ]

By Dhaval Patel, Kim Witte, Charles Vaught, Michael T. Stephenson, Steve Booth-Butterfield, Cynthia Zuckerman, Brian L. Quick

This longitudinal field study was designed to encourage Appalachian coal miners in West Virginia and Pennsylvania to engage in hearing-protection behaviors. Method: Participants were mailed postcards that featured either a positive, negative, or neutral message on the outside of the postcard and a message encouraging hearing protection behaviors on the inside. The first posttest measurement of the effectiveness of the persuasive messages was conducted about a week after the postcards were mailed. The delayed posttest measurement was conducted six weeks later. Results: Responses from 307 coal miners revealed that the positive or neutral messages generated significantly more self-reported hearing protection behaviors than the negative message. Identical results were obtained in a delayed posttest assessment of miners' self-reported hearing protection behaviors. The positive message was also more effective than either the neutral or negative message in preventing defensive mechanisms from emerging over time. Impact on Industry: Positive and neutral messages were convincingly more than negative messages in facilitating self-reported hearing protection behaviors among coal miners. Similarly, the positive messages kept defensive processes at bay. Keywords: Hearing protection; Hearing loss; Coal miners; Campaign; Messages

By John C. Edwards

Chapman-Jouguet detonation calculations were carried out for pentaerythri-tol tetranitrate (PETN), TNT, and ammonium nitrate-fuel oil (AN-FO) explosives using the compressibility form of an equation of state of hard spheres based upon Percus-Yevick (PY) theory, and a chemical equilibrium detonation code called TIGER. Similar calculations were also carried out with the Becker-Kistiakowsky-Wilson (BKW) equation of state. For PETN, the BKW equation gives somewhat better agreement with experimental values of detonation velocity and pressure. However, in terms of experimental temperatures and concentrations of the minor product species (NO), the predictions of the PY equation are shown to be more satisfactory. Similar comparisons of experimental and theoretical results for TNT and AN-FO indicate that the PY equation has general utility in predicting the detonation properties of condensed explosives at moderate loading densities (Po < 1.3 g/cm3).

Jan 1, 1974

By Arcy P., D&apos Banister

Several gold-antimony geochemical anomalies were outlined near Stibnite, Idaho, using the humus sampling technique. Several hundred reconnaissance humus samples were collected and analyzed by a combination fire-assay atomic absorption method. The results partially outlined several gold-antimony anomalies and are very encouraging for further work in this part of Idaho.

Jan 1, 1970

By Oscar Lee

"Flotation is generally regarded as a process that is only applicable to metallic minerals. However, its scope is now known to be greater than this, because some of the nonmetallic minerals are floatable, such as graphite, sulphur, and fluorite. Recent observations show that limestone may be added to the list of floatable nonmetallic minerals. Such work is being done on a laboratory scale at the Southern Experiment Station (Tuscaloosa, Ala.) of the Bureau of Mines, Department of Commerce, where experimental magnetic concentration of the low-grade iron ores of the Birmingham district is in progress. Certain experiments have demonstrated that the limestone may be floated from the magnetic log-washer tailing, and then incorporated in the iron concentrate.If the loss of lime could be prevented, some ores though low in iron and high in insoluble contain enough lime to make their concentrates self-fluxing. Since this loss in the magnetic log-washer can not be avoided, the Time must be recovered from the tailing by some method and added to the magnetic iron concentrate before sintering. Then the resulting concentrate will be self-fluxing.While seeking a suitable means of treating the tailing for recovery of lime, flotation was tried. It was at once evident that this method had possibilities, during the early part of the investigation, soap solution made from a common soap was used as a flotation reagent. The froth obtained was a fairly good lime concentrate. This result was an important clue, and led to tests with the use of such reagents as oleic acid and sodium oleate. Later, cresol, creosote, coal tar and other similar flotation reagents were tested in combination with the oleic acid and soap solutions. As a result, oleic acid and cresol used together were found to be satisfactory.The tailing from the magnetic log-washer is in excellent physical condition fur flotation. The iron ore had been ground in a ball mill to 100 mesh for magnetic concentration. Hence the bond between the lime carbonate and the other constituents of the tailing was well broken."

Apr 1, 1926

By Harry W. Campbell

A mineral survey conducted by the U.S. Bureau of Mines in 1984 identified no mineral resources or prospects with mineral development potential in the Pit River Canyon Wilderness Study Area (WSA). Basalt suitable for aggregate and fill is in the WSA but rock of this nature is abundant in the region and closer to potential markets.

Jan 1, 1984

By Roy L. Wilfong

Surface area measurements were conducted on cadmium sulfide powders following thermal treatments at temperatures up to 500° C and treatment times up to 1 week. Thermal treatments at temperatures up to 300° C produced no significant changes in the surface area of the powders even after 1 week of exposure. At 500° C some decomposition of the cadmium sulfide occurred.

Jan 1, 1970

By J. P. Rider

Average production from longwall mining operations in the United States has risen from approximately 800 tons per shift in 1980 to over 4,600 metric tons per shift in 1999. Such a large increase in production has the potential to generate significantly more dust. Previous NIOSH research has shown that, on average, respirable dust levels generated by the shearer accounts for 50% of the airborne dust generated during longwall mining. Ventilating air and water are primary controls being used in an effort to reduce longwall dust levels. Longwall operators are applying more air and water than ever before and have expressed concern over reaching maximum practical limits for these controls. Full-scale laboratory tests are being conducted to evaluate the impact on shearer-generated dust levels for changes in face air velocity, water quantity at the shearer, water spray pressure, spray system design, mining height and cutting direction. Results of this research should identify the most appropriate control levels for various operating conditions. In addition, general recommended dust control practices for longwall mining will be discussed. KEYWORDS Longwall, coal dust

Apr 1, 1975

By R. E. Peterson

The Bureau of Mines has undertaken beneficiation investigations on samples representing large tonnages of oxidized taconites in order to develop and evaluate applicable technologies for producing iron oxide concentrates from these materials. Information derived from the investigations can be used to expand the domestic iron raw-materials base and to establish the impact these taconite deposits may have on future national iron ore requirements. This report describes a process that includes reduction roasting, magnetic separation, and flotation, applied to a western Mesabi Range sample taken near Coleraine, Minn. The sample contained 36.8 pct iron and 46.0 pct silica, and represented 0.5 to 1 billion tons of crude material. An average of 962 lb/hr of oxidized taconite was roasted with 33 lb/hr of lignite in a 35-foot-long rotary kiln. Pulverized lignite and natural gas maintained the kiln operating temperature at 850° C. The roasted taconite was beneficiated by magnetic separation and cationic flotation in a 900-lb/hr pilot plant and yielded a product analyzing 68.1 pct iron and 4.6 pct silica, and containing 82.4 pct of the iron in the kiln feed.

Jan 1, 1981

By A. B. Hooker, L. C. IlsLey

The greatest hazard of early mining was from explosions of methane ignited by open lights . With the advent of safety lamps and forced ventilation this hazard was greatly reduced until the application of electricity to modern mining not only multiplied the sources of gas ignition but the accompanying , machines and haulage systems increased the amount of explosive dust , through which a methane explosion is more liable to become a major mine disaster , and thus greatly furthered the need of adequate ventilation to keep down the concentrations of methane . Adequate ventilation is still the best preventive of such explosions . However , even with a well laid out and controlled ventilating system the amount of air passing through entries and rooms is liable to vary within wide limits because of open doors , falls of rock , or other accidental causes . The percentages of methane under normal conditions should therefore be kept so small that they will not be increased to explosive proportions by short interruptions in ventilation . Mine ventilation and methane detection are inseparable safety precautions . The increasing importance of ventilation necessitates more accurato determinations of the methane concentrations throughout the mines . This paper discusses in detail some of the steps in the development of methane detection and specially notes the more accurate detectors now available . One of the earliest means of detecting methane was by a candle . About 1835 , John Buddle , Sr. , a noted mining man of his period , when questioned by a Parliamentary Committee as to the safety of using candles , replied :

Jun 1, 1933

By Harry Dobroski, Larry G. Stolarczyk

Medium-frequency (MF) techniques have been successfully .[pplied] to the problem of radio voice communications in both coal and metal and nonmental mines. Long range is achieved by taking advantage of existing mine conductors that carry and propagate the signal over vast areas. It is very likely that in the near future such systems will become the referred method for general mine communications. MF techniques can also be applied to the areas of in-mine control and monitoring. Preliminary work in this area is described. In a western mine, locomotives are being operated under MF remote control in a loading operation. In several eastern mines, MF has been evaluated as a method for monitoring the status of devices in remote areas of the mines. All control and monitor information uses existing mine conductors.

By F. M. Carlson

Comparisons are made between the results of the Buckley-Leverett and Kern solutions, which describe immiscible displacement of oil by gas in a linear system and the results obtained from a less restrictive numerical model. This model takes into account the effect of compressibility of the oil and gas and the effect of allowing changes in the amount of gas in solution in the oil. These effects are best exemplified by imposing large pressure drops across the system. With these large pressure drops, comparison of the model solution with the Buckley-Leverett solution reveals that the Buckley-Leverett solution provides estimates of recoveries at breakthrough of the gas that are too low. In contrast to the model, the Kern solution predicts breakthrough recoveries that are too high. A modification to the Kern solution is presented to facilitate more accurate predictions of recovery at gas breakthrough for gas injection at pressures higher than the saturation pressure of the oil.

Jan 1, 1974

"It is evident that the incidence of coal worker's pneumoconiosis (CWP) or black lung disease varies in different coal producing regions of the United States. Many people have hypothesized about the reasons for the differing occurrences. Because underground coal mining involves many mining methods under changing geological conditions, several factors may be involved in contracting CWP such as: the amount of quartz in the respirable dust, the trace elements in the respirable dust, the rank of the coal that produced the respirable dust (bituminous, anthracite), the amount and size of respirable dust, etc.Recognizing the uniqueness of underground coal mining and CWP, research investigations involving seam characteristics, mining system and worker position are being conducted in the center to establish standard procedures for characterizing some coal properties that may be involved in workers contracting CWP. This has been accomplished by the in-mine sampling of airborne dust at various worker locations and mining system configuration and by performing laboratory analyses of mined material (coal and rock) taken from the mines. (FIGURE 49 and 50)The investigations includes a method of classifying coal seams according to their potential to generate respirable dust. It includes statistical analyses of the size and locational variations of the elemental compositions of respirable coal mine dust in operating underground mines from seams located in the eastern, midwestern, and western United States, and is currently completing research which is investigating the relationship between the elemental compositions of respirable dust sampled near a continuous-mining machine and a laboratory-produced respirable dust."

Nov 1, 1988

By F. W. Penn

An aircraft auxiliary power unit (APU) was used as an exhaust source for evaluation and refinement of sampling and analytical procedures for gas turbine engines. The unit was also used to determine the emission characteristics of APU&apos;s in service and to study the effect of fuel composition and combustor design on exhaust emissions. Carbon monoxide, carbon dioxide, oxides of nitrogen, hydrocarbons, aldehydes, particulate loading, and odor were measured at engine operating modes representing the duty cycle encountered in airline operation. Analyses showed good repeatability, and adequate sensitivity was attained in these experiments. Smoke opacity measurements were not taken owing to the lack of a high-sensitivity smokemeter. Results showed that the minimum emission levels occurred with the standard combustor and Jet A fuel. Emission rates were highly dependent on test mode, but emission patterns as a function of test mode were similar for all fuels and combustors tested. A comparison of three identical design production combustors showed a variation in average emission rates of less than 5 pct.

Jan 1, 1973