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By George E. Blandford

A deterministic model to assess the hydrologic impact of small watersheds subjected to unsteady storm events is presented. The overland flow model is based on the kinematic wave approximation coupled with a Green-Ampt infiltration equation. The Green-Ampt infiltration parameters are estimated using the USDA-ARS parameter estimation technique which is based on soil moisture-tension data. A Galerkin finite element formulation of the kinematic wave approximation is presented for the deterministic analysis of overland flow on small watersheds. The finite element formulation includes linear, quadratic and cubic Lagrangian one-dimensional spatial elements. A linear time variation is assumed which includes both explicit and implicit time marching algorithms, depending on the choice of the time weighting parameter. The implicit time algorithms result in a system of nonlinear equations which are evaluated using a modified Newton-Raphson iteration scheme. Initial solution estimates are generated using a linear finite difference procedure. The coupled infiltration overland flow model is tested using storm data for impervious surfaces, a laboratory soil flume, and two natural, USDA-ARS experimental watersheds.

Jan 1, 1983

By Charles Vaught

The purpose of this study was to determine mine workers' state of fie-fighting preparedness and the technology being used to detect and respond to underground coal mine fires. To investigate this problem, 214 underground coal miners were interviewed by U.S. Bureau of Mines researchers. Frequency distributions of workers' responses are presented in this report, along with segments of narrative accounts, to profile miners' fire-fighting capabilities. The data indicated that much variability exists from mine to mine and that there are several important changes operators may undertake in order to make miners better prepared to deal with fire underground: select appropriate sensors, establish and test a warning and communication protocol, construct a system capable of delivering hundreds of gallons of water per minute for sustained periods, institute formal fire preparedness audits, develop case studies of events that occur at an operation to use as teaching and assessment tools, and provide structured practice that can be incorporated into fire drills.

Jan 1, 2010

By J. M. Mutmansky, C. Lee

"This paper outlines some of the work associated with a research study into the relationship between the characteristics of coal mine dust and the incidence of coal workers' pneumoconiosis (CWP). The project involves study of the chemical, mineralogical, and morphological characteristics of the dust. Early stages of the study have dealt primarily with the size analysis and elemental composition of airborne dust in continuous miner sections. This paper outlines the procedures and findings of the elemental analysis portion of the study.Most of the previous elemental analyses of coal were made available in the quest for information on the combustibility of coal dust or on causal agents and prevalence of CWP. However, no extensive studies have been performed to date, primarily due to the limitations of the analytical methods. A review of the analytical methods for elemental characterization of coal and coal dust particles is presented. TI1e comparisons are made based on the sample mass required, the sample preparation required, the destructivity of the test, and the capability of providing an easy multi-element analysis. The reasons for selecting the proton-induced x-ray emission spectroscopy (PIXE) method are outlined.The PIXE method was applied to both the airborne coal mine dust and channel samples collected from seven continuous miner sections in six different mines. Channel samples of the coal, roof and floor were collected and analyzed. Airborne dust sampling was performed using multi-stage cascade impactors and permissible 2.0 I/min pumps. Sampler locations were fixed in the sections with respect to the continuous miner and roof bolter or with respect to the intake and return airways. Sampling times varied from 45 minutes to 6 hours, depending on the dust concentration.The statistical analysis of the resulting elemental data is presented. Of particular importance are the analyses of the variation of elemental composition with size and the variation in elemental composition over the working section. One interesting finding is outlined showing the multivariate statistical analysis of the trace elements and its implications in the identification of the dust sources. The paper concludes with an analysis of the ramifications of the elemental data to related medical studies."

Mar 1, 1989

By Henry M. Harris, John E. Kelley, Thomas D. Roberts

A penetrometer apparatus for measuring viscosity of glass at temperatures up to 1,450 ° C was developed for use in establishing the viscosity coefficients required for high- temperature forming of ceramic materials . The major advantage of the method is that it can be used with samples of almost any shape or size without the necessity of forming or measuring shapes to close dimensional tolerances . Also , it has proved accurate in the range of 106 to 109 poises , a gap between the normal limits of other methods . The device , which operates on a single penetrometer principle , was used to determine the absolute viscosity coefficient of substances in centimeter - gram- second units of poises instead of relative penetration - rate units as with other penetrometers . Penetration of the viscous sample was sensed with a linear , variable differential transformer . The output of this transformer was recorded versus time , and the penetration rate was used in calculating the viscosity coefficient . The general equation relating penetration rate and viscosity coefficient was found to be 11 = F ( ln L/a 0.72 ) 2 π UL · where is the viscosity coefficient in poises , F is the penetrator load in dynes , L is the penetration depth in centimeters, a is the penetrator radius in centimeters and U is the penetration rate in centimeters per second . The penetrometer was tested using a standard viscosity sample of sodalime - silica glass obtained from the National Bureau of Standards ( NBS ) . Values obtained at several temperatures all agreed within 10 percent with comparable data calculated from the Fulcher equation derived by NBS for this glass . Equivalent accuracy was obtained with other glasses used to evaluate the apparatus .

Jan 1, 1964

By M. M. Fine

"INTRODUCTION One of the principal activities of the Bureau of Mines during the recent war was to help to increase the supply of strategic and critical minerals. Fluorite was one of the most critical of the nonmetallic minerals because of the increased demand for it as a flux in basic open-hearth and electric steel furnaces and as a raw material for the production of artificial cryolite used in the aluminum industry. Wartime developments in the technology of hydro-fluoric acid, such as the use of the anhydrous acid as a catalyst in high-octane-gasoline production and the use of organic fluorides as carriers for insecticides, also increased the demand for acid-grade fluorspar. 2/ In 1943 the consumption of acid-grade fluorspar was advancing at a more rapid rate than production and was only slightly less than production during the latter half of the year.The outlook for the postwar market for fluorspar is encouraging. Steel production is expected to remain high until the domestic demand for commodities not manufactured during the war is satisfied. The uses for hydrofluoric acid also are expected to increase under the impetus of war-initiated research. In consideration of these and other factors some authorities predict a new peacetime demand for fluorspar equal to 60 to 75 percent of the war production, 5/ 6/ and others believe that the fluorspar industry will be permanently expanded. 7/"

Dec 1, 1947

By W. H. Carrington, A. C. Richardson

"INTRODUCTION The Powhatan mine of the Franklin Coal Mining Co. is located in the western part of Jefferson County, Ala., on the Louisville and Nashville Railroad, 40 miles west of Birmingham. The Mary Lee bed at this point yields coal with fair coking qualities, but with an ash content as mined so high as to prohibit its use in the production of metallurgical coke. At present the entire output of the mine is washed in single-compartment jigs and marketed as locomotive and domestic fuel.Figure 1 gives a typical seam section of the Mary Lee bed at the Powhatan mine. This section shows that the bed is divided by rock partings into three benches. In many parts of the mine, particularly in the older workings the roof rock is so weak that it can not be held without excessive timbering. This condition has restricted the operation in many parts of the mins to the middle and bottom benches of coal. The 6 inches of draw rock between the top and middle benches is very strong and makes an excellent roof requiring only a normal amount of timbering to support it. In the newer workings of the mine the character of the rock above the top bench is strong and it is believed that in the future it will be possible to work all three benches. This study was undertaken for the purpose of determining the washing characteristics of the Mary Lee bed at Powhatan and the effect on these characteris-tics of including or omitting the coal from the top bench. It was also the purpose of the study to show whether it would be possible to produce a washed product sufficiently low in ash to be used for the manufacture of metallurgical coke. This paper is one of a series of reports on the washability of Alabama coals which is being prepared by the U. S. Bureau of Mines and tin University of Alabama. With the cooperation of the coal producers of Alabama. It contains the results of screen sizing and float-and-sink tests of representative samples of run-of-mine coal, and the results of table tests on the minus 3/16-inch sizes of the raw coal."

Apr 1, 1933

By M. M. Fine

This Bureau of Mines report describes the theory, experimental procedures, and the results obtained to date in the development of the Bureau's process for magnetically roasting iron ores using scrap iron as a means of reduction. Since magnetic separation is an operational step common to magnetic taconite plants, the preliminary research studies emphasized only the novel magnetic roasting step. The studies included the use of automobile scrap, ferrous reductants such as borings and turnings, and prereduced pellets. Technical feasibility of the process was demonstrated both on a bench- and pilot-scale. Quality magnetic concentrates with recoveries of over 90 percent were obtained from a direct shipping ore containing 59.5 percent Fe and from fine grained semitaconites with about 30 percent Fe.

Jan 1, 1966

Researchers with the National Institute for Occupational Safety and Health (NIOSH) have developed a training module to educate both new, inexperienced miners as well as veterans on important issues related to self-rescue and escape procedures. These include: (1) physical and environmental conditions that can be encountered in a mine after a major explosion, (2) knowledge of emergency meeting locations and escape routes, (3) the importance of using self-rescuers, even in seemingly clear air, to keep the lungs isolated from contaminants, and (4) why miners should not go off to look for others who are missing. In addition, the module may stimulate miners to think about and discuss mine explosions and the devastating effects of such an event.

May 1, 2009

By R. Hogg, T. F. Dumm, L. G. Austin, M. Yekeler

"Dedicated to Professor Kurt Leschonski on the occasion of his 60th birthdayAbstractThe kinetics of batch grinding quartz from a feed of 600 by 425 Jim to a product of 80% less than 10 µm have been determined using screening and laser diffractometer sizing for size analysis. The specific rates of breakage decreased by a factor of about three when the material became less than about 100 µm in size, but the primary breakage distribution function also changed to give proponionately more fine material, so that the grinding efficiency expressed as the development of surface area (B.E:T.) per unit of energy input did not decrease. Analysis of the shape of the particles in the 2S x 38 µm size range showed that particles of this size produced by roll crushing or by 8 minutes of grinding of a 42S x 600 µm feed were not different but at long grinding times the particles were rounded. This suggests that the breakage mechanism changes to give more chipping and abrasion and less disintegrative fracture. As the material approached the ultrafine size range it adhered to the mill case and there was no further size reduction. However, a technique for striking the mill case to dislodge the particles was successful in allowing further grinding to 400Jo by weight less than 2 µm.1 IntroductionIt has long been known that it is difficult to accomplish ultrafme grinding in a tumbling ball mill. It has been reported [12, 13] that there is no further size reduction after some hours of grinding cement clinker in laboratory ball mills. Austin and Bagga (1] and Shah and Austin [16] have given an analysis of the kinetics of dry grinding in a laboratory ball mill, introducing the concept of a slowing-down factor K, which is the ratio of the specific rates of breakage at some long time of grinding to the normal specific rates of breakage. They showed that this factor decreased as fine material accumulated in the mill charge. Cottaar and co-workers [8-10] showed that the movement of solid in a dry laboratory ball mill was influenced by the fineness of the solid and by the presence of air, and that evacuation of air from the mill caused particle sedimentation and low rates of breakage.The concept of the slowing-down factor has also been used in wet grinding [17, 18]. At very .high slurry concentrations it appears to be correlated with a steady decrease of mill power caused by the build up of a layer of deposit sticking to the mill case. This reduces the effective mill diameter and, eventually, the balls start to adhere in the layer and centrifuge. A decrease of mill power always indicates less lifting and tumbling of the media and, hence, less breakage. However, slowing-down of breakage rates was also observed at lower slurry concentrations where there was no change in mill power."

Jan 1, 1990

By Robert W. Geehan

A preliminary examination of the Dayton iron deposit was made in 1941 and 1942 by Paul E. Pesonen and O. H. Metzger, engineers of the Bureau of Nines. Trenching and sampling were recommended, to be followed by core drilling if favorable results were obtained. The Bureau of Mines conducted a project at the property from June to December 1942. The deposit is in sec. 6, T. 17 N., R. 23 E.; sec. 31, T. 18 N., R. 23 E.; sec. 36, T. 18 N., R. 22 E.; and sec. 1, T. 17 N., R. 22 E., M. D. B. & M., about 15 miles west of Lahontan Reservoir in Lyon and Storey Counties, Nev. It lies at an altitude of about 4,500 feet north of the Carson Plains, in the foothill section of mountains that rise to about 7,000 feet to the north of the property. The deposit may be reached by driving 12.5 miles northeast of Dayton over U. S. Highway 50, thence northerly 2.7 miles over a dirt road to the property. The climate is hot and dry in summer, with occasional thunderstorms some of cloudburst variety, and frequent high winds. Winters are usually moderate, with light snowfall and some subfreezing temperature.

Jan 1, 1949

By N. A. C. Smith, D. D. Stark

"Sulphur is apparently a normal Constituent of crude petroleum, but in most crudes is present in percentages of less than one-half of one per cent. Some crudes, however, contain more, and occurrences have been reported of heavy asphaltic oils with as much as five per cent of sulphur.Occurrences of Sulpher-bearing CrudesIn North America, the fields rest of the Mississippi River are almost entirely free from sulphur oils, the time oil from Northern Ohio and Indiana, and the Potrolia crude in Ontario, being practically the only ones which contain sulohur in amounts over 0.5. per cent. In the Mid-Continent district the production of high sulphur crude in general is small and unim¬portant. The two main excentions are the Healdton field in Oklahoma and the El Dorado field in Arkansas, both of which produce oils with considerable sulphur content. In the Wyoming field, one sand, the Ember Sandstone, pro¬duces a crude of high sulphur content, and it is probable that this crude rill be of considerable importance as production increases. At present, however, very little crude is produced from this formation. In the Gulf Coast conditions are irregular, some crudes being low in sulphur and others comparatively high. The same is largely true of California. The crudes of Mexico contain notable amounts of sulphur, and as they have been of great commercial importance in this country, a typical sample of light Mexican crude was selected for the present study. It is probable that the results obtained poly also (but to a lesser degree) to other sulphur-bearing oils. An analysis of this crude will be found in Table 3, also analyses of other typical sulphur-bearing crudes from different sections of the United States."

Mar 1, 1924

By M. R. Geer

This report presents the results of washability examinations of seven coals from the principal coal-producing fields of Montana. A complete performance test of the Baum-type jig operated at one of the mines is included, as are the results of cleaning tests made on two of the coals in a dense-medium pilot plant. The coals examined from the Red Lodge, Bull Mountain, and Forsyth fields are comparatively easy to clean. Ash contents of 5 to 10 percent can be obtained at yields of washed coal ranging from 90 to 95 percent. The coal from the Great Falls field, however, could not be cleaned readily to less than 14 percent ash, and the rejection of impurity would amount to over 25 percent. The two coals treated in the dense-medium pilot plant were characterized by sharp separation of impurity, high recovery efficiency, and satisfactory reduction in ash content.

Jan 1, 1955

By N. A. Eilertsen

This report describes field investigations conducted in 1953 of two occurrences of manganese and a separate magnetic anomaly in the Southern manganese district of Aroostook County, vicinity of Houlton, Maine -the Pierce deposits, in Hammond Plantation Township; the Burnham anomaly, also in Hammond Plantation; and the Nickerson-Farm prospect in Hodgdon Township. The manganese occurs in a thinly laminated sedimentary rock containing manganiferous carbonate interlayered with fine-grained metamorphosed sediment, rich in chlorite or hematite. The surrounding rocks are mostly dark gray-green slates. Samples composited for metallurgical testing from the Pierce deposits and the Nickerson-Farm prospect assayed 9.0 to 12.3 percent of manganese. More than 90 percent of the manganese could be extracted with sulfuric acid, but in most instances 30 to 40 percent of the iron was also extracted. Leaching tests indicated that, after being reduced in a hydrogen stmosphere at 600° C., about 85 percent of the manganese could be selectively extracted by a solution of ammonia-ammonium carbonate with iron extraction of only 14 percent.

Jan 1, 1958

This Part describes a mine pager phone to public telephone interconnect sys tem that permits mine paging telephones to be selectively interconnected with the public telephone system, as illustrated by Figure 1. This interconnect concept was first conceived and demonstrated in breadboard form by H. E. Parkinson of Industrial Hazards and Communications, PMSRC, as one means for providing improved emergency and off-hours communications. The third-generation prototype unit described in this Part was designed and fabricated by Arthur D. Little, Inc. This unit is a small desk-top or wall-mounted unit that connects directly to both the public telephone line and the mine pager phone line, and requires no modifications to either the public dial telephone or mine pager phones. As part of this task, ADL also built, under a very compressed time schedule, a second-generation prototype unit suitable for reliable demonstration of the interconnect concept during the Bureau's technology transfer seminar on mine communications in March 1973. * A major objective of the design of the third-generation unit described in this Part was that it be compatible with present mine pager phone systems utilizing DC voltage on the mine phone line to activate the phone loudspeakers. Therefore, this unit was designed to operate in a push- to-talk, push-to-listen mode that accommodates the inherent design differences and operation modes of the mine phones of different manufacturers. Though this push- to- talk, push- to-listen mode of operation may seem slightly unusual at first sight, we have found it is easily learned by new users. However, mine phone manufacturers wishing to expand their product lines with such an interconnect system will probably find it to their advantage to customize the design of this system to their particular mine phones, thereby utilizing the unique attributes offered by their individual product lines. This customization should not be difficult, and Section III below suggests some of the features that can be easily added to future designs. Detailed parts lists and circuit schematics for the present third-generation proto- type system can be obtained from the system manual submitted to PMSRC and placed on public file.

Jan 1, 1974

By W. G. Pariseau

A U.S. Bureau of Mines case study of pillar recovery in high-grade ore near the Ross shaft at the Homestake Mine, Lead, SD, has demonstrated the usefulness of the finite-element method for evaluating shaft pillar mining plans and shaft stability. This report focuses on mine measurements and calibration of the two-dimensional computer model and is the second in a series of three Reports of Investigations describing the Ross shaft study. In this study, borehole extensometers and other instruments were installed to provide data for model verification and to monitor the shaft. Results of the recalibrated two-dimensional model (UTAH2) confirmed the premining stability evaluation. However, after mining began, concern was expressed because cracks and other signs of ground motion appeared at considerable distances from the area of active pillar mining. In part 3 of the study, an intensive three-dimensional modeling effort using UTAH3 was initiated. The results again showed that the observed effects were within expectations and that the shaft would remain safe. Three-dimensional analyses of alternative pillar mining scenarios indicated that more of the shaft pillar ore reserve could be recovered than previously thought.

Jan 1, 2010

By C. H. Fisher

[Many methods of analyzing tar oils for their tar acid and base content have bun employed in connection with both academic and. industrial investigations. Most of these analytical procedures are based on the diminution in volume caused by extraction with alkali and mineral acids (contraction method), although other methods haves been employed.4/ In many instances the adoption of an analytical method was not preceded by adequate study, and, as a consequence, the literature, on this subject is conspicuous for its contradictory claims and recommendations. It has bin shown in the, case of certain synthetic solutions5/ that large errors may result if the analysis is carried out by simple extraction with alkali and mineral acids.]

Jan 1, 1936

By R. W. Stahl

Gas accumulation and dust suspension are the major safety hazards in coal stockpiling and reclaiming operations. This report presents a schedule of safety precautions and plant design features devised by the Bureau of Mines to reduce danger from these and other sources.

Jan 1, 1965

By Charles L. Kimbell

World political events that occurred subsequent to yearend 1989 but that bear heavily on the global mineral industry have been of such significance that they cannot be disregarded, and certainly they contribute to any type of "outlook?. However, to write of them simply as "forecasts" in an "outlook" section of this study would be to unjustly pretend to status as prophets. Thus, this section covers events that have occurred not as predictions but rather as history. The section also includes an element with some broad statistical information, but this is included last rather than first for two reasons: the information is subject to considerable re- vision as additional data become available and as preliminary returns are corrected; and the authors view it as less important than the events that govern the statistics. The Near East and the Crisis There.- Of all 1990 political events influencing the world's mineral industry, the Iraqi invasion of Kuwait and the remarkable events that followed this aggression must head the list. The almost immediate imposition of economic sanctions, involving embargoes on shipment of virtually all goods into and out of Iraq, caused severe dislocations in the production and trade of mineral commodities, not only within the region itself, but with a ripple effect, into other world areas as well.

Jan 1, 1992

By W. Miola, R. V. Ramaoi

"The MSHA prescribed method for the determination of quartz in airborne respirable-dust samples from underground coal mines is the P-7 method, a combination of /ow-temperature, radio-frequency ashing (LTA) and infra7 red analysis (IR). There is no prescribed procedure for quartz analysis in bulk samples of coal and host rock. Dispersive infrared (IR), Fourier-transform infrared (FTIR) and X-ray diffraction (XRD) methods are most commonly used for the analysis of quartz in powders. Several aspects of the experimental procedures, such as the preparation of the analysis sample from bulk samples, ashing techniques, scanning procedures, peak measurement location, calibration techniques, sample amounts, size consist and data interpretation, affect the results from each of the methods differently. Significant differences in analytical results obtained from X-ray diffraction (XRD) and infrared spectroscopy (IR) on the same samples are reported. All studies point to the need for reliable quartz analysis methods.In a recent research program, a procedure for preparing bulk-coal and host-rock samples for quantitative quartz analysis was developed. Further, the results from X-ray diffractometry and infrared spectroscopy for quartz content on identical samples were compared. Calibrations with pure and mixed standards were used to assess the influence of particle-size distribution, matrix and calibration on the analytical results. In this paper, several issues concerning the measurement of quartz in the samples of coal, host-rock and airborne respirable dust from mines are outlined and quantified. IntroductionThe literature on coal-mine airborne-dust control has identified a need for a better understanding of the sources, mechanisms and amounts of quartz in mine airborne respirable dust (Althouse, 1984; Jankowski, Nesbit and Kissel, 1985; Ramani 1988; Qin, 1988; Bhaskar and Xu, 1990; Bhaskar and Li, 1992; Ramani, Qin and Miola, 1991 ). To understand the quartz content in the source materials, bulk samples of coal and host rock must be analyzed. Establishing an analysis procedure for determining the quartz content in bulk-coal and host-rock samples is necessary for identifying the sources of quartz in mines; for establishing the relationships between the quartz contained in the source and in the airborne dust; and for controlling the content of quartz in the mined product and in the airborne respirable dust."

Dec 1, 1996

By Stephen A. Hare, O&apos

Powder metallurgy processing of commercial Raney nickel powders was examined. The typical angular particle shape, in conjuction with aluminum present in a eutectic phase, facilitated interlocking leading to excellent green strength after compaction. Density and porosity as influenced by the compacting pressure were studied over the range of 37.5 to 207 meganewton per square meter (MN/m2). Sintering in an inert atmosphere from 575° to 850° C caused a volume increase which is attributed to a solid state reaction between Al and Ni2Al3 phases. The reaction is 3Al + Ni2Al3 ? 2NiA13. A thermal pretreatment of 70 hours at 700° C was required to prevent this reaction from occurring during sintering. Density and porosity as a function of compacting pressure and sintering temperature were determined after a thermal pretreatment of the powder.

Jan 1, 1976