Search Documents

By I. A. Jacobson

In a closely controlled laboratory retorting system for oil shale, a relationship was developed by the Bureau of Mines between the temperature in the retort and the weight ratio of ethylene to ethane in the gases produced. Reciprocal temperature was shown to be directly proportional to the log ([ethylene]/[ethane]). From this relationship a number, called retorting index, was developed. The retorting index has the dimension of temperature, but its magnitude depends on both temperature and residence time for the reactants in the heated zone in the oil-shale retort. The slopes of the lines relating reciprocal temperature and the logarithm of the ethylene-ethane ratios are nearly constant for each of the retorting processes for which data have been presented. The retorting index should be a valuable tool to control the operation of oil-shale retorts, either aboveground or in situ. If an optimum operating condition can be established, the maintenance of the optimum or the departure from it should be easily monitored by use of the index.

Jan 1, 1974

By N. E. Hanna

To be authorized for use in coal mines, explosives and blasting devices must pass certain safety tests prescribed in schedule 1F,3/ on the basis of extensive practical and theoretical research by the Explosives Testing Station of the Federal Bureau of Mines. An explosive or blasting device that passes these tests is placed on the active permissible list. As this list is constantly revised, it has been the practice of the Bureau of Mines periodically to publish the names of explosives and blasting devices that have been added to the active list, as well as those that have been transferred to the inactive list; changes in brand names also are reported. This circular covers all permissibles including additions, transfers, and changes made between December 31, 1945,4/ and December 31, 1951.

Jan 1, 1952

By Alfred E. Schwaneke

An improved maximum-bubble-pressure system using the Sugden twin-capillary method for measuring the surface tension and density of molten metals is described. Improvements include (1) internally ground capillary tips, (2) electronic pressure transducers, (3) micrometer adjustment of immersion depth for density measurements, (4) valuing arrangements to allow operation at other than atmospheric pressure, (5) temperature range to 1,100° C, and (6) recorder readout of pressures. Data for surface tension of mercury from 20° to 300° C are given.

Jan 1, 1970

By Samuel R. M. Burton

This Bureau of Mines report describes a method for determining parts per million (ppm) of helium-4 (He-4) in helium-3 (He-3) to an accuracy of ±5% by mass spectrometry. Gravimetrically prepared primary standards were used for the calibration of a Dempster 1800 magnetic sector mass spectrometer. A comparison between a 2.49% He-4 in hydrogen mixture and a 2.49% He-4 in He-3 mixture shows that He-3 can be replaced with hydrogen as a diluent for standards with comparable mass spectrometry sensitivities for He-4. Using hydrogen as a diluent allows analysis of He-3 samples for He-4 when He-3 for preparation of standards is not available and also conserves the rare He-3 isotope. Standards of He-4 in Hz were prepared for calibration of the mass spectrometer for quantitative determinations of He-4 in the 2-to 100-ppm range. A minimum detectable limit of 2 ppm He-4 is obtained by this method.

Jan 1, 1989

By Harry R. Nicholls

As part of the pre- and post - shot mine examination at Project GNOME , acceleration data were recorded underground from a series of chemical explosive shots . The cube root of the charge weight was used to scale acceleration and distance because charge weight was not constant . Regression analysis of particle acceleration - distance data gave the following propagation equation : A W1 /3 = 5.10 x 105 ( R / W¹ / 3 ) −2 .43 The quantity A W1 /3 is scaled particle acceleration expressed in g's - lbs¹ / 3 , and R/W1 /3 is scaled distance expressed in ft / lbs¹ /3 Data obtained from the nuclear explosion were scaled and fall within one standard deviation of the calculated propagation law for the smaller shots . Cube root scaling laws were adequate to group acceleration data from explosive charges varying by a factor of more than 1 x 10 in charge weight and over shot - to - gage distances varying from 100 to 46,000 feet . Data obtained from a series of small tests provided sufficient data from which reliable predictions of acceleration could be made for the large nuclear explosion .

Jan 1, 1964

Studies on coal mine drainage sludge densification have led to the following conclusions: 1. Coal mine waters containing iron principally in the ferrous (Fea+) state can be treated by a modification of the commonly practiced lime neutralization process to yield a ferromagnetic sludge. The sludge, presumably composed in large part of a hydrated ferrosoferric oxide (Fe304.xH20), is much denser and faster settling than the ordinary "yellowboy" sludge obtained by lime neutralization and aeration at ambient temperatures. 2. The magnetic sludge preparation technique involves (quantitative) precipitation of iron (largely as Fe(OH)2) by the addition of hydrated lime to a pH of 8.5, separation of the resulting sludge from the aqueous phase, and heating of the sludge concentrate to at least 80 C (176 F), preferably higher, followed by mild aeration. 3. Magnesium, present as Mg2 in most coal mine drainage waters, inhibits the formation of the magnetic sludge. This inhibition can be adequately minimized by keeping the pH below 9.6 during lime addition (thus avoiding the coprecipitation of Mg(OH)2) and by separating the sludge from the bulk of the aqueous phase before the heating step, as indicated in (2) above. 4. Aluminum, commonly present in coal mine drainage waters, also inhibits the formation of the magnetic sludge. This inhibition is of practical significance when the molar ratio of aluminum/total iron is greater than 0.18. Below this value, sludges are still appreciably magnetic, but are bulkier and slower settling than those obtained when aluminum is absent. Unlike magnesium inhibition, aluminum inhibition cannot be minimized by the scheme indicated above, since aluminum precipitates as Al(OH)3 near pH 4 and remains dispersed within the sludge. 5. The limitation on aluminum content is probably the most serious restriction affecting the feasibility of the magnetic sludge process as presently conceived. Nevertheless, a limited review of available water quality data has indicated that, in terms of relative acid and iron loadings, a significant number of major coal mine discharges in the eastern Ohio River basin may be amenable to treatment by a magnetic sludge process. 6. Data from tests on the use of magnetic seeding materials indicate that seeding did not enhance the formation of a magnetic sludge under the experimental conditions employed.

Jan 1, 1971

By R. J. Shanley

This report presents a computer code that has been developed by the Bureau of Mines for isolating naturally occurring clusters of data plotted on the unit hemisphere and testing these clusters against a probability distribution which admits elliptical symmetry about its mean. A listing of the computer code is provided along with an example output illustrating the delineation and analysis of clusters in fracture orientations measured in a porphyry copper deposit.

Jan 1, 1975

By Wm. C. Dean

The location of trapped miners from their seismic signals will be in- accurate if we assume the P-wave propagation velocity is a constant. P- wave velocities are anything but constant in regions about mines, so some calibration is necessary to obtain more accurate seismic locations. The reference event method compares the time arrivals of signals generated by the miners with those previously recorded from a reference or calibration event in the vicinity of the miners. This method locates the miners' position relative to the calibration source. Hence, the location of the miners is absolute if the reference event position is known absolutely, usually from surveys and mine maps. Advantages resulting from the system, besides greater accuracy, are locations independent of the velocity model assumed, the same solution from the full array and from any subset of four or more seismometers in the array (three if the miners' depth is known), fewer seismometers required, and no complex computers required for analysis. VELA Uniform experience shows that the accuracy of locations of teleseismic explosions and earthquakes is improved by an order of magnitude over locations computed from average travel time curves. Each calibration event is applicable only over a limited range. We recommend a field test of the method at a mine to measure its location accuracy, the range of effectiveness for each calibration event, the number of seismometers needed, and the number of reference events required per mine. From these experiments we could decide whether the reference event method was useful and, if so, what form a practical rescue system would take.

Jan 1, 1974

By A. D. Garman

This paper presents one of a series of digests of foreign mining legislation and court decisions which is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate mines in various foreign countries. This interpretation of the laws of Guatemala has been prepared from the best available information in Washington, but is released subject to correction and amplification, if necessary, by the proper American diplomatic and consular officers to whom it is being referred through the courtesy of the Department of State.

Oct 1, 1929

By E. O. Bennett

Various methods of making leakage tests have been tried during a study of losses in the transmission of natural gas. This work has been carried on by the Bureau of Mines in cooperation with the Natural Gas Association of America. Results of tests show that the "shut-in pressure-drop" method described by Rawlins2 is the most accurate and reliable; therefore its use is recommended. This paper describes a graphic method for computing the rate of leakage from the fall in pressure and change in temperature determined by the "shut-in pressure-drop" method of testing. METHOD OF MEASURING PRESSURE DROP The gas is "shut in" the line to be tested and is not allowed to escape except through existing leaks. The leakage causes the pressure in the line to fall. The change in pressure is obtained with a dead weight gage. Approximate results may also be obtained from readings on a good spring test gage. Numerous tests show that the dead weight gage is more sensitive to small changes in pressure than spring gages.

Jan 1, 1926

By Lippe D. Sadwin

A high-speed streak camera method for making equation of state measurements (shock and particle velocities) on samples of rock under dynamic load conditions is described. Experimental data are given for tests on 12 samples representing 5 rock types. Analysis of these data shows that the method is practical and that good reproducibility of results can be obtained. The pressure range covered in the tests was from 1 to 50 kilobars.

Jan 1, 1966

By E. J. Matson

The Little Castle Creek chromite deposit was examined in February and May 1941, respectively, by W. O. Vandenburg and O. H. Metzger, engineers of the Bureau of Mines. The Federal Geological Survey started a magnetometer survey of the area in November 1940 and completed its work during April and May 1941. Field work by the Bureau of Mines was conducted during May and June 1941. The purpose of the Bureau of Mines investigation was to search for a continuation of the chromite mineralization. The property at one time was the largest chromite producer in California.

Jan 1, 1949

By J. L. Stauffer, L. Gaydos, L. M. Demers, D. C. Kuhn

"Eicosanoids and cylokines produced by the pulmonary alveolar macrophage (PAM) are key mediators for the defensive role this cell plays in neutralizing the inhalation of particulate dusts and foreign microbes. However, these factors are also mediators of inflammation and their uncontrolled release may cause the lung injury and liorotic changes observed in individuals exposed occupationally to mineral dust. In vitro studies have suggested a link between the production of certain eicosanoids and cylokines released from the activated PAM. To this end, we have studied the release of eicosanoids (PGE2, TXB2 and LTB4) and cylokines (IL-1 and TNF) by cultured PAM, obtained from healthy human volunteers by bronchoalveolar lavage under basal culture conditions and following acute exposure to provocative agents such as the endotoxin lipopolysaccharide (LPS) and mineral dusts including silica. Studies were also carried out in the presence of specific cyclooxygenase inhibitors. The addition of LPS (10 µg/ml) to the culture medium produced a significant increase in PAM release of the eicosanoids: PGE2 (3.5 fold over baseline), TXB2 (2.8 fold over baseline) and LTB4 (4 fold over baseline). LPS also elicited a 2.5 fold elevation in IL-1 from these cells and a 9 fold increase in TNF release. The cyclooxygenase inhibitor, ibuprofen, significantly inhibited the LPS-induced rise in PGE2, TXB2 and TNF but had only a modest suppressive effect on IL-1 release. Exposure of these cells to silica dust elicited a similar augmentation in eicosanoid and cylokine release which was neutralized by prior exposure of the cells to ibuprofen. These results suggest that the enhanced production of eicosanoids and cytokines by PAM exposed to endotoxins and/or mineral dusts may be linked and that inhibition of eicosanoid release is linked to the production of TNF. IL-1 release however is not effectively neutralized by cyclooxygenase inhibition.INTRODUCTIONThe initial pulmonary cellular response to inhaled mineral dust involves the elaboration of potent inflammatory mediators from the pulmonary alveolar macrophage (1). These mediators include the eicosanoids (oxygenated metabolites of arachidonic acid) and cytokines (intercellular peptides) which are released into the alveolar space by the interaction of mineral dust with the PAM surface membrane. The eicosanoids and cytokines promote local nonvascular and vascular smooth muscle contractility changes, elicit the recruitment of additional mononuclear cells into the alveolar space, and enhance the activation, growth and differentiation of lung fibroblasts (2). In this study we sought to examine whether eicosanoid release and metabolism are linked to cytokine release when PAM are activated upon exposure to endotoxin or mineral dusts. Modulation of these pathways through inhibitory pharmaceutical agents may help attenuate the Injurious effects caused by a sustained release of these proinftammatory intercellular factors (3). To that end, we have studied the in vitro effects of endotoxin and silica on eicosanoid and cytokine release from cultured PAM obtained from healthy human volunteers."

Mar 1, 1992

By R. A. Pallanch

This paper, which describes the milling practice at the Midvale concentrator, is one of a series being prepared by the Bureau of Mines. The Midvale concentrator, a custom lead-zinc selective flotation plant, is in Salt Lake County, Utah, on a flat site several hundred yards east of the Jordan River and about 200 yards south of the Denver & Rio Grande Western Railroad tracks leading to Bingham Canyon. The site is at an elevation of about 50 feet above the river, the highest available location, thus allowing maximum storage of tailings.

Jan 1, 1931

By Kevin A. Rider, Bernard J. Martin

Reaching movements are planned and subsequently executed [1] using visual and somatosensory feedbacks [2], where absence of visual feedback is known to increase endpoint variability [3]. Visual occlusion decreases the ability to make rapid online compensatory movements, which results in initial radial deviations that are highly correlated with radial dispersion at the target. Perturbations of rapid, visually-guided reaches are compensated on-line and result in endpoint dispersions poorly correlated with initial deviations, emphasizing the strong effect of visual feedback in temporally-constrained reaching tasks. In control conditions (no vibration), these uncompensated, rapid reaches serve as estimates of the individual’s intended trajectory. When ride motion is present, trajectories of rapid, visually-occluded reaches provide a measure of the natural biodynamic response of the cantilevered spine-arm-hand linkage. These intended movement trajectories and the biodynamic response (vibration feedthrough) are used to predict the effect of ride motion on the performance of rapid reaching tasks. Goals of this study are to investigate the influences of vehicle motion on human reaching and pointing, and to reveal movement strategies used in visually-occluded reaching tasks. Methods A six degree of freedom human-rated Ride Motion Simulator (RMS) was used to generate a dynamic vehicle environment. Participants performed discrete, rapid pointing tasks to targets presented on three touchpanel displays under stationary and random whole-body vibration. Reach instructions included successfully reaching identical circular targets (Ø = 0.25”) with the right index fingertip as fast as possible. Targets were presented on resistive-touch displays mounted approximately 60 cm from the participant’s nasion. The touchpanel displays were located in the forward and lateral directions at eye level, and forward at 45° of elevation. These displays measured the spatial error of the reach destination. A ten-camera VICON motion capture system recorded the upper body kinematics of the participant. Reflective markers were placed on the participant’s torso, head, and arms. Initial kinematics of the fingertip (i.e. time and magnitude peak tangential velocity) and tangential velocity at target were used to estimate the planned endpoint of the reach. Results and Discussion Ride motion resulted in increased endpoint variability compared to reaches performed in the stationary condition. Reaches to the elevated touchpanel consistently resulted in the largest variability across all motion conditions, suggesting that a vehicle occupant would not be capable of accurately activating a control in that location. Principal axes of endpoint ellipses were along and perpendicular to the direction of fingertip movements. Example graphs of endpoint variability with ellipses containing 95% of the data points are shown in Figure 1. These ellipses

Jan 6, 2006

By Donald O. Capstick

A mineral survey of a 13,525-acre portion of the 21,875-acre Owyhee Canyon Wilderness Study Area in northern Nevada was conducted by the U.S. Bureau of Mines in 1984. Two samples from sand and gravel deposits in the study area contained minor placer gold typical of the Owyhee River area. The gold-bearing gravels are too low grade or of insufficient volume to support commercial placer mining operations. The sand and gravel deposits might have minor local construction uses.

Jan 1, 1986

By L. W. Brandt

Studies of liquid-vapor equilibria of gas mixtures at the Bureau of Mines Amarillo Helium Plant Laboratory require that the equilibrium cell be maintained uniformly at any desired temperature from approximately room temperature to -320° F. The temperature-control system must also tolerate a substantial heat input, in the form of warm gas flowing into the cell, without loss of control. Temperatures between the sublimation temperature of carbon dioxide (-109° F.) and the boiling point of liquid nitrogen (320° F.) are usually obtained by methods utilizing a hydrocarbon liquid bath cooled by liquid nitrogen.4/5/6/7/ Owing to the fire hazard attending such baths, a safer method of temperature control was desirable.

Jan 1, 1955

Enable prospective in situ leach mine operators to evaluate the economic potential of an ore body by using a user-friendly, computerized in situ copper oxide leach mining cost model. Background As part of its research on in situ leach mining technology, the Bureau of Mines produced a 5-volume contract report that mining companies can use to design an in situ mining operation for copper oxide deposits. Written for the Bureau by the Science Applications International Corporation (SAIC) in 1988, the generic design manual also contains a computerized cost model for evaluating the economic feasibility of in situ leach mining for any specific copper oxide deposit. The cost model is to be used with Volume II of the contract report. But because of certain complexities associated with running it, the Bureau found that the model could be improved by making it more user friendly. Approach The approach taken by Bureau researchers to make the original model more user friendly was to incorporate a HELP function to define input parameters, and to enable the display of output on the monitor. An accompanying handbook, U.S. Bureau of Mines Information Circular (IC) 9284, contains further details on running, the 1990 model.

Jan 1, 1991

By Richard L. Lewis

This is a discussion of the application of the zonal harmonic series to problems involving dipole sources in the vicinity of spherical boundaries. The application of a formal zonal-harmonic series solution to directly obtain numerical results involves two distinct problems: namely, the convergence of the series solution and the accurate calculation of the special functions involved in the series solution. Some interesting techniques will be introduced which help to improve the convergence properties of the series solution.

Jan 1, 1973

By Robert H. Merrill

A method of determining the strength of a mine roof layer in place is described in this report. The method was tested on a limestone roof layer 50 feet wide, 100 feet long, and 20 inches thick. In place measurements were accomplished by introducing air under pressure into a separation between the layer and the overlying roof, and as pressure was increased, the corresponding strain and deflection of the roof layer were measured until the roof failed. The ultimate strength of the roof agreed with the tensile strength of the roof rock (modulus of rupture) as determined in the laboratory; the modulus of elasticity as measured in place did not agree with the laboratory-determined values; the deflection and tensile strain in the layer in place showed good agreement with the theory of a body-loaded beam clamped at both ends. This procedure for determining the strength of a mine-roof layer is safer and less costly than successively widening a roof to failure. For example, it would have been necessary to mine the room to a width of 114 feet and a length of 228 feet to produce failure in this roof layer. The method is not necessarily limited to limestone; any thinly bedded rock type can be tested by this procedure when there is an open parting over the mined area.

Jan 1, 1958