Search Documents

By G. W. Jones

[A survey of the Ii terature reJ.l....ting to iE;li tion temperatures of acet-ylene-air and acetylene-oxygen mixtures reveals rather '.'fide disagreement in the reported results. In SO!':1e instances the i ition temperatures of acet?-ylene-air mixtures were reported to be lower than those of acetylene-oTjgan mixtlU'es, which is contrary to experience 'tri th other combustibles. ':10 clea.r up some of t!le reported discrepancies, the authorn have icvestigated the igni tion temperatures of acetylene both in air anri oxygen, and their results are presented in this report.]

Jan 1, 1941

By G. W. Marks, A. H. Roberson

"Previous investigation 4/ has demonstrated that some of the aliphatic amines are suitable absorbents for 302, This paper reports the results of physical studies of a number of such amines with the object of determining which is most favorable as an absorbent.Monoethanol amine, diethylene triamine, and triethylene tetramine appear to be the most promising of all the amines studied, and most of this report has been devoted to studies of the physical properties of their aqueous solutions, which contain varying amounts of SO2.PURITY OF MATERIALSAll of the amines used were of commercial grade, because the primary object of this research was the investigation of a proposed works process rather than the accumulation of scientific data.The aminoethyl derivitives of ethylene diamine, namely, diethylene triamine, triethylene tetramine, and tetraethylene pentamine, only recently have been produced commercially. The chemistry of aliphatic amines is complex, and these newer derivitives have not been investigated, completely. Chemically pure material is not on the market, and since definite physical standards have not been published, one could not be assured of a pure product even if the commercial material was refined.The compilation of physical constants for the pure amines would involve much time—consuming effort without materially enhancing the value of this paper, as this work was not devoted to the development of fundamental standards."

Oct 1, 1938

By Sara Jane Boles

The purpose of this Bureau of Mines investigation was primarily to isolate and examine the effect of liquid content upon the apparent porosity and bulk density of compacts pressed from high-purity, fused aluminum oxide, and, secondarily, to study the actual mechanism by which the liquid content affects the bulk density. No attempt was made to approach the theoretical maximum density of the oxide by introducing additives, particle packings, or similar variables; instead this study is an intercomparison of the bulk densities obtained as functions of the water contents of the compacting mixtures. Water content was varied from 7 percent to 25 percent, on a total-weight basis. The data gathered indicated a well-defined optimum water content for obtaining minimum apparent porosity and maximum bulk density, under the conditions of the experiment. During the course of this study, a number of additional variables in the forming process were discovered and are introduced in this report, although a thorough evaluation was found to be beyond the scope of this present investigation.

Jan 1, 1963

By David Gearhart, Thomas Barczak

Hydraulic cylinders a re used in several roof support systems, such as longwall shields and mobile roof supports, to provide critical ground control Many state-of-the-art hydraulic support systems operate at pressures as high as 7,000 psi to provide the necessary support capacities. Pressure in the upper stages of multi-stage cylinders can be intensified by a factor of 2 or 3 providing pressures of 20,000 psi or greater. A proper understanding of the operation of these high pressure systems is necessary to safely maintain and repair these support systems. Likewise, the performance characteristics need to be fully understood to evaluate the impact of design parameters on the capability of the support to maintain effective ground control. This paper examines the basic operating principles of state-of-the-art hydraulic cylinders and discusses relative issues pertaining to. (1) setting loads, (2) support stiffness, (3) yielding behavior, (4) errors in assessing support loading, and (S) hydraulic failure mechanisms and how to detect them

By W. H. Oppelt

The continuous gasification of lignite in an externally heated alloy-steel re-tort was investigated by the Bureau of Mines, Grand Forks, N. Dak., from 1945 to 1951. The main objective of the long-term experimental program was to obtain data on the mechanical performance of this type of gasification retort, particularly the alloy-steel heat-transfer surface of the retort, when operated on large pilot-plant scale. At the same time, extensive experimental data were obtained concerning the effect of process variables and the effect of a limited number of design modifications on gasifier performance. In the period covered by this progress report 4 pilot-plant runs totaling 2,879 hours of operation were completed with the rolled-plate, 310-alloy reaction tube. Over 30 million cubic feet of gas, having H2-CO ratios from 2.1 to 4.4, was made by the partial gasification of 636 tons of 1-1/2-by 3/8-inch natural lignite. Rates of gas generation were from 8,200 to 14,300 cubic feet per hour. Three of the four runs were carried out with the lowered gas offtake or continuous-annulus design modification of the gasification retort. In the final run of the series, gasification of lignite from seven different mines in North Dakota and Saskatchewan, Canada, was investigated at similar combustion-space temperatures and lignite and steam feed rates.

Jan 1, 1955

By R. C. Annear

This report describes open, sublevel, and shrinkage stoping at the Greenwood mine, operated by Inland Steel-Co. The iron ore mine is in Marquette County, Mich., about 6 miles southwest of Ishpeming (fig. 1). The Greenwood is one of three active underground hard-ore mines on the Marquette range, the others being the Cliffs-Shaft and the Champion mines. The operation reflects an achievement in exploiting small, difficult-to-mine hard-ore bodies lying beneath a 200-foot overburden of glacial drift, which is partly water bearing. This report can indicate only briefly the efforts of personnel in overcoming adverse conditions in mining more than 2 million tons of ore, 80 percent of which was in lump form, for open-hearth production of steel. Significant data presented include descriptions of the principal mining methods employed, sublevel and shrinkage stoping; percent aged mining costs for the entire year 1957, covering both direct mining costs and general expenses; and performance records in units of labor, power, and supplies.

Jan 1, 1960

By E. G. King

The Bureau of Mines made experimental determinations of the heats of formation of forsterite and chrysotile at 298.15° K. The heat capacities of two polymorphs of serpentine, chrysotile and antigorite, were measured over the temperature range from 50° to 298° K and the entropies at 298.15° K were evaluated. The heat content of antigorite above 298.15° K was measured to 850° K. These thermochemical data were combined with other pertinent data to give heat and free energy of formation values at high temperatures. Free energy values are given for the reaction, forsterite + water = brucite + serpentine at different temperatures and pressures.

Jan 1, 1967

By M. L. Glenn

The Bureau of Mines is conducting research on substitutes for chromium-containing alloys in order to conserve imported critical and strategic materials. Part of this research concentrates on finding low-chromium substitutes for heat-resisting stainless steels for the temperature range 600° to 800° C. Ferritic alloys are emphasized that have oxidation resistance provided by chromium contents as low as 10 pct and stress rupture strength provided by the precipitation of the chi(X)-phase intermetallic compound, (Fe36Cr12 (Mo, Ti)10). Initially, research was concentrated on selecting an alloy composition having a minimum chromium content with strengthening provided by the X-phase. An Fe-(10-12 pct)Cr-6 pct Mo-(1.5-2.0 pct)Ti alloy was selected. After the alloy selection, the tensile, stress rupture, and oxidation properties were determined. Stress rupture properties were found to be similar to those of 304 stainless steel. However, the alloys possessed brittleness during both stress rupture and tensile testing, possibly as a result of too high a content of molybdenum and titanium. Higher than expected oxidation rates were found that may be caused by the high molybdenum content.

Jan 1, 1984

By Andrew M. Leszcykowski

In 1984, personnel from the U.S. Bureau of Mines examined the 9,550-acre Yatahoney Creek Wilderness Study Area (WSA) for mineral resources. This study area, in southwestern Idaho, is underlain by tuffs and basalt of Tertiary age. Owyhee County mining records and U.S. Bureau of Land Management records, and other references were examined prior to the field study. There are no known mines, claims, or prospects in or near the WSA. No evidence of mineral deposits or occurrences was observed. Oil and gas leases or lease applications are in the southern portion and northeast corner of the WSA. Although placer gold exists in the Owyhee River drainage, there are insufficient deposits of gold-bearing gravel in the Yatahoney Creek WSA to enable mining. INTRODUCTION The U.S. Bureau of Mines (USBM) and the U.S. Geological Survey (USGS) conduct mineral surveys of designated wilderness study areas (WSAs) 1/ to ensure mineral values that may be present are considered in wilderness recommendations. The USBM examines known mines, prospects, and mineralized sites, and the USGS performs geologic mapping, and geochemical and geophysical surveys on an areal basis.

Jan 1, 1986

By Susan Brink

The U.S. Bureau of Mines is investigating the potential of in situ leach mining a variety of Cu, Mn, and Au-Ag ores. Geologic characterization of ore samples from laboratory leaching experiments is conducted both prior to and after leaching to assess the effects of leaching on the chemistry, mineralogy, and texture of the rocks. The identification and chemical compositions of ore, gangue, and reaction products are determined by a combination of techniques such as reflected and transmitted light microscopy, X-ray diffraction, electron diffraction, electron microprobe analysis, and backscattered electron imaging with scanning electron microscopy. The distribution of the desired metal in various mineral phases can be illustrated using elemental X-ray maps. The potential of reactive gangue minerals to rob Cu from leach solutions is investigated with the aid of transmission electron microscopy. Porosity and permeability are measured to determine how effectively the host rock can transmit leach solution. Textural relationships between ore, gangue, secondary reaction products, and fluid channelways are determined by petrographic examination and are documented by optical photomicrographs and secondary electron imaging. Representative sample selection is described, and several epoxy impregnation and sample mounting techniques are discussed.

Jan 1, 1991

By Frank J. Perzak

This report describes a U.S. Bureau of Mines study on the hazards of large-scale conveyor belt fires in underground coal mines, as a function of both air velocity and distance from belt surface to gallery roof. The fire hazards considered were smoke obscuration, toxic effects of carbon monoxide (CO), and elevated air temperatures downstream of the fire. All of these hazards scale with the ratio of fire intensity to ventilation airflow. These hazards were all found to be greater at the lower belt-to-roof distance, owing to the greater fire intensities that resulted. The hazards of smoke obscuration and elevated CO levels were greater at lower air velocities. Smoke obscuration was found to be the earliest hazard, reaching critical levels before the stage of belt flame spread. Critical levels of CO and downstream air temperatures were not reached until the later stages of flame spread. Fire growth rates during rapid flame spread were much greater than rates measured during the early stages of belt burning. Data were analyzed to determine the early-warning capability of fire sensors. Smoke sensors provided the earliest warning, followed closely by CO sensors. Thermal sensors did not exhibit any early warning capability.

Jan 1, 2010

By J. V. Scalera

Because of U.S. dependency on imported critical metals, the Bureau of Mines has conducted research to evaluate the possible substitution of nitrided low-alloy steels for higher chromium-containing alloys. The corrosion data for nitrided steels are limited primarily to the Soviet literature. The objective of this study was to determine the corrosion properties of six commercially nitrided low-alloy steels in a 5-wt % NaCl solution at pH 4. Weight-loss tests indicated that, in deaerated test solutions, most of the nitrided steels were less corrosion resist-ant than nontreated steels. However, electrochemical tests indicated that under more oxidizing conditions, nitrided materials are converted to a passive state with a significantly reduced corrosion rate. Elec-trochemical tests performed in an aerated environment confirmed the passivity of the samples in an oxidizing environment.

Jan 1, 1984

By L. C. Karrick

The Bureau of Nines has received many inquiries on the subject of assaying oil-shales, both from individuals who desire to wake their own assay while in the field, and also from Commercial assayers and investigators. The present paper describes the assay retort used by the Bureau of Mines. in the research work on oil-shales now in progress at the Intermountain Experiment Station of the Bureau at Salt Lake City, Utah, and at the Colorado cooperative oil-shale laboratory, Boulder, Colorado. This retort, which was developed through experimentation in the bureau's laboratories, has been found to be convenient in use and. capable of yielding reproducible results. M. J. Gavin, Oil-Shale Technologist, gave valuable assistance in preparing the subject matter for publication and made many helpful suggestions during the experiments made by the writer in the course of the development of the assay retort. L. A. Anderson, research "fellow" University of Utah, assisted in the preliminary development of the assay retort.

Jan 1, 1921

By W. D. Mcmillan

"Magnetic surveys made by the Missouri Bureau of Geology and Mines in 931 and 1932 disclosed a large positive anomaly about a mile south of Bourbon, Mo. 3/ Electrical resistivity measurements made by the Division of Geophysical Exploration of the Bureau of Mines in the winter of 1942-43 indicated that the source of this anomaly was in the pre-Cambrian rhyolite at a depth of more than 1,400 feet. 4/In order to determine the character of the material that caused the magnetic anomaly, which might be either a body of magnetite or a large intrusive of basic rock, the Bureau of Mines drilled four holes to depths of 1,800 to 2,300 feet. Magnetite in rhyolite porphyry was encountered at 1,600 to 2,000 feet, and this is doubtless the main source of the magnetic anomaly, although it is possible that additional iron ore exists at greater depth.Hole 1 was apparently located southeast of the source of the anomaly and encountered only small stringers of magnetite. Hole 2 penetrated four mineralized zones having a total thickness of 125.7 feet and an average weighted content of 43.52 percent iron and 31.62 percent silica. These zones were tested again by a deflection hole, 2A, which gave nearly identical indications. Hole 3, 500 feet north of hole 2, penetrated 58 foot of mineralized rhyolito containing an average 43.4 percent iron.Metallurgical tests showed that the silica in the ore is tightly locked with the magnetite. After grinding to minus 100 mesh, a 66 percent iron con¬centrate with 7 percent silica was obtained by flotation."

Oct 1, 1946

By N. L. Wimmler

"INRODUCTIONSedimentary deposits of titaniferrous magnetite occur at various localities in the eastern foothills of the Teton Ranse in Deer Lodge County, Mont. The Choteau deposit was examined by a Bureau of Mines engineer in August 1942. An exploration project was recommended.Core drilling exploration was begun in June 1945; it was concluded in August 1945, Seventy-six holes were drilled. This report presents the data obtained by the Bureau of Mines exploration.ACKNOWLEDGMENTIn its program of exploration of mineral, deposits, the Bureau of Mines has as its primary objective, the more effective utilization of our mineral resources to the end that they make the greatest possible contri¬bution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, Chief, conducts preliminary examination, performs the actual exploratory work, and prepares the final, report. The. Metallurgical Branch, R. G. Knickerbocker, Chief, analyzes samples and performs beneficiation tests. Both of these branches are under the supervision of Dr. R. S. Dean, Assistant-Director. The field work was supervised by Earshel W. Newman, engineer in charge of the Helena Field Office. D. B. Hoiekvam was the project engineer; he provided most of the data used in the preparation of this report."

Dec 1, 1946

By Timothy J. Rohrbacher

This report presents a U.S. Bureau of Mines study that incorporates coal mining factors, coal recovery factors, and economic factors into the definition of an economically recoverable coal resource. The relationship between these factors to the Energy Information Administration's estimate of U.S. coal resources-the "Demonstrated Reserve Base"-is discussed. The Matewan 7-1/2 minute quadrangle in eastern Kentucky was selected as the initial study area. Results indicate that of the original 1,193 million tons of resource in the quadrangle, only 89 million tons (7.5%) are economically recoverable at a cost of $25 per ton or less. At the current production rate of 5.3 million tons per year, this represents only 16.8 years of remaining reserves.

Jan 1, 1993

By Raghoottma S. Pandurangi, Mohindar S. Seehra

"The interaction of amorphous 1ilica particles with several hydrogen bonding agents (H2O, C2H5OH, C7H2NO) was investigated by monitoring the changes in the bulk and surface IR vibrational modes of silica using photoacoustic spectroscopy. It is argued that the intensity of the silanol band at 3747 cm-1 provides (an inverse) quantitative measure of the interaction or surface groups, along with the shift in the broad hydroxyl band, the interaction following the order C7H2NO > C2H5OH > H2O. Index Headings: Silica; Surface vibrational modes; Photoacoustic spectroscopy; Hydrogen bonding agents.INTRODUCTIONThe use of m spectroscopy to study the adsorption on solid surfaces is well documented in the literature.1 2 For example, hydroxylation of a clean silica surface results in the formation of the free silanol group Si-OH, with a sharp IR band near 3747 cm-1• Further hydroxylation produces a broad band near 3500 cm-1, which is believed to result from various hydrogen-bonded silanol bands leading to a multilayered surface structure of few nm.3-5 Earlier studies had indicated a relationship between the surface silanol band and various chemical activities of silica such as cytotoxicity, 7- 9 catalysis, 10-12 and others.13 Recent studies from our group14-in which the intensity of the silanol band and cytotoxicity of silica, heat-treated at various temperatures up to 1095°C, were investigated have provided a strong correlation between cytotoxicity and intensity of the silanol band.Coating of silica by PVPNO (polyvinyl-2-pyridine N-oxide with the empirical formula C7H8NO), a strong hydrogen bonding agent, is known to reduce the cytotoxicity of silica, presumably by chemically blocking the silanol groups from phospholipids.15 This interaction of the hydrogen bonding agents with the silica can be studied by m spectroscopy, and Knozinger16 and Rouxlet and Semples11 have used transmission m spectroscopy to study the effect of various chemicals on the surface IR modes of silica. However, one of the major disadvantages of transmission IR spectroscopy is that the sample preparation (grinding and mixing with KBr and pelletizing) usually distorts the surface modes (see, e.g., Ref. 14) and there is always a doubt about the effect of the sample preparation on the measured properties. In recent years, photoacoustic (PA) spectroscopy has become the technique of choice for studying the IR spectra of samples in their natural state, since no sample preparation is necessary.18•19 Moreover, according to a recent paper, 20 the relative intensity of the surface modes in PA spectroscopy of silica particles is much higher than that in transmission FT-IR spectroscopy. Consequently PA spectroscopy is ideal for studying the surface chemistry. In this work, we have used PA spectroscopy to investigate the interaction of three hydrogen bonding agents (C7H8NO, C2H50H, and H20) with the silica surface by monitoring changes in the surface m modes. Our results show that the surface IR modes get perturbed to a larger extent than the bulk IR modes in interaction with the hydrogen bonding agents. Moreover, whereas in the earlier studies, the shift of the broad silanol band near 3500 cm-1 was used as a measure of the interaction with hydrogen bonding agents,16•17 here we show that the relative decrease in the intensity of the sharp silanol band near 3747 cm-1 also serves as a quantitative parameter for the relative surface coverage and surface modification. Details of this work are given below."

Jan 1, 1990

By K. L. Erickson, Gerald A. Munson

"The need for spodumene as a source of lithia for war purposes led to the exploitation of the Edison pegmatite deposit 1-1/2 miles southeast of Keystone, S. Dak. The operation was conducted during 1943 and 1944 by the Lor Mining Co., Rapid City, S. Dak. Spodumene concentrates in the ratio of 15:1 were recovered by hand picking from a sorting belt. This method was expensive and wasteful of spodumene, owing to the small size of the crystals.Data4/ obtained by the Bureau of Mines indicates that blunging with hydroflouric acid or sodium hydroxide is a prerequisite to selective flotation. Results of tests by Denver Equipment Co., Denver, Colo., indicate that economic recoveries can be obtained in an alkaline circuit after desliming.At the request of the Lor Mining Co., K. L. Erickson, metallurgical engineer, was permitted to work in the pegmatite research laboratory to verify previous investigations and to determine problems that might be involved in commercial milling. The ensuing investigation indicated that electrolytes in the mill water produced a profound inhibiting action on the flotation of Edison spodumone.An investigation of mill water from various sources showed that some waters are suitable for the process and others are not. Subsequent testing showed that all of the available waters are suitable after treatment. The flotation of the Edison spodumene in an alkaline circuit after desliming and using oleic acid as collector is efficient and economical when the water does not contain impurities.In its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B.Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches arc under the supervision of Dr. R. S. Dean, assistant director.As the work was of a practical nature, samples from possible mill-water sources in the southern Black Hills were obtained, and commercial softening and demineralizing methods were investigated. Data on various waters tested are given in table 1."

Jun 1, 1946

By J. R. Ross

Techniques for recovering scandium from uranium plant iron sludges and from wolframite concentrates are described. The best procedure found comprised (1) dissolution with sulfuric acid, (2) preliminary concentration by solvent extraction with a primary alkyl amine, (3) further enrichment and purification by a combination of ion exchange, solvent extraction, chemical precipitation, and calcination. Recovery of scandium from these raw materials, which contained 0.058 and 0.14 percent scandium, ranged from 83 to 90 percent in products analyzing 99.6 to 99.9 percent scandium oxide.

Jan 1, 1965

By G. E. McElroy

This report discusses the construction and use of an all-pressure psychrometric chart in which the requirements of simplicity of appearance and absolute accuracy have been waived, to a certain extent, to provide for the rapid determination of psychrometric data and for the rapid solution of air-conditioning problems of major interest to the mining industry. Many mines in which air-conditioning problems are important are situated at elevations far above sea level and embrace great differences in elevation - in excess of 8,000 feet in certain mines - throughout their airflow circuits. Under these conditions, the effects of variations in the pressure of the atmosphere upon the physical properties of the mixture of air and water vapor of which it is composed are considerable and should be taken into account in the solution of problems. The simple types of psychrometric charts in common use, such as the Carrier, Bulkeley, Hill, and Goff (American Society of Heating and Ventilating Engineers Guide), are not generally suitable, in that they are drawn for a single barometric pressure - 29.92 inches mercury.

Dec 1, 1947