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By R. L. Montgomery

Heats of solution of cerium metal and cerium (III) chloride in hydrochloric acid were measured. The standard heat of formation of the aqueous cerium (III) ion at 25° C is -166.1 ± 0.3 kcal/mole. Heats of solution of cerium (III) chloride in hydrochloric acid are consistent with the existence of a complex CeC1++ having a stability constant of 1 and a heat of complexing of 5.4 kcal/mole.

Jan 1, 1962

By J. B. Gayle

The Bureau of Mines sole-heated oven has been used for studying coal expansion for some 20 years. During the period before 1940 emphasis was placed on studies of the mechanism of coal expansion and the effects of variations in operating conditions on the results. Since 1940 emphasis has shifted to a survey of the expansion properties of various coking coals. Because additional information concerning a number of unsolved problems in connection with the earlier studies appeared highly desirable, this investigation of the use of sole-heated ovens for studying coal expansion was undertaken. The principal findings, in order of their discussion in the text, may be summarized as follows. 1. Expansion results for binary blends of coking coals exhibit nonadditive behavior, both positive and negative deviations from additive behavior being noted, depending on the particular coals tested. Additive behavior can be achieved, however, either by charging the blend components in separate layers (which indicates that the observed phenomena are not characteristic of the particular expansion oven used) or by testing relatively coarse sizes of coal (which suggests that the effects of crushing on the expansion properties of coking coals may be even more complex than is generally recognized).

Jan 1, 1959

By d&apos, Kathleen J. Amico

THIS SUMMARY appears in Minerals Yearbook volumes I and III, which cover mineral production in the United States, its island possessions, the Canal Zone, and the Commonwealth of Puerto Rico, as well as the principal minerals imported into and exported from the United States. The several commodity and area chapters contain further details on production. A summary table comparing world and U .S. mineral production also is included. Mineral production may be measured at any of several stages of extraction and processing. The stage of measurement used in the chapter is normally what is termed ?mine output." It usually refers to minerals in the form in which they are first extracted from the ground, but customarily includes for some minerals the product of auxiliary processing operations at or near mines.

Jan 1, 1965

By Frank A. Peters

This description of process evaluation techniques used by the Bureau of Mines for studying proposed processing techniques has been prepared to provide those interested in using these studies with an understanding of the methodology. The methods used for preparing both capital and operating cost estimates are described. Each step in preparing the evaluations is described. Types of equipment costs are shown and factors used in the estimates are defined. Uses of the estimates are suggested and several examples are included. The accuracy of various types of estimates is discussed, along with an explanation of the reason for selecting the type used in the Bureau's process evaluation studies.

Jan 1, 1987

By d&apos, Kathleen J. Amico

THIS SUMMARY appears in Minerals Yearbook volumes I and III, which cover mineral production in the United States, its island possessions, the Canal Zone, and the Commonwealth of Puerto Rico, as well as the principal minerals imported into and exported from the United States. The several commodity and area chapters contain further details on production. A summary table comparing world and U.S. mineral production also is included. Mineral production may be measured at any of several stages of extraction and processing. The stage of measurement used in the chapter is normally what is termed "mine output." It usually refers to minerals in the form in which they are first extracted from the ground, but customarily includes for some minerals the product of auxiliary processing operatons at or near mines.

Jan 1, 1963

By R. D. Leitch

The pollution of streams by acid mine drainage has become of great importance in the past few years in certain regions of the United States. Large quantities of acids are used in a discharged from other industries than mining, notably in tube, sheet, tin-plate and era hell inn works. These are usually less important then coal mines as a source of acid drainage, because of their more limited distribution throughout the States most affected by acid waters and their relatively smaller numbers. Streams are naturally alkaline and are, therefore, able to take care of rather large quantities of acid wastes, but when such enormous quantities as are often found in mining districts enter the streams, the natural alkalinity is quickly overcome. When a neutral or almost neutral condition has been reached, the further addition of a relatively slight quantity of acids will cause a great difference in the quality of the water.

Jan 1, 1926

By Clete R. Stephan, Mark J. Schultz, William A. Slivensky, Eric S. Weiss, Kenneth W. Jackson

he Pittsburgh Research Center (PRC)~ and the Mine Safety and Health Administration (MSHA) are participating in a research program to evaluate the strength characteristics and air leakage resistance of seals and water trap designs for use in underground coal mines. This program is being conducted at PRC's Lake Lynn Laboratory near Fairchance, Fayette County, PA. Seals designed with a 40-cm-thick polymer (polyurethane) and aggregate core between two dry-stacked (no mortar) concrete block walls (coated on out by sides) withstood a 138-kPa pressure pulse while maintaining acceptable air leakage rates. Similar seal designs utilizing a 97-cm-thick, 91-kg/m7-density, polymer-only core did not survive; however, a 5 1 -cm-thick, 203-kg/mi-density, polymer-only core seal successfully withstood the explosion pressures. Evaluations of cellular concrete seal designs have shown that a two-pour slurry injection technique did not adversely affect the strength of the 1.2-m-thick seals when subjected to a 138-kPa pressure pulse. Two seal designs utilizing low-density cementitious block have also been evaluated with successful results. In addition to seal strength tests, various 15- and 30-cm-diam U-shaped water trap pipes and a water trough design were evaluated under explosion conditions and were shown to be inadequate when evaluated under worst-case conditions. Simple modifications to the various water trap designs were successfu1 in preventing the passage of explosion flame through the trap.

Jan 4, 1996

By D. R. Tesarik

An instrumentation and numeric modeling study was conducted by the Bureau of Mines at the Magmont Mine in Bixby, MO. An isolated section of this room-and-pillar mine was monitored with borehole and closure extensometers during a pillar recovery program to determine stress redistribution. In situ stress measurements were taken in the rib before pillar extraction began. Sample cores from the boreholes were taken for analysis of the properties of the host rock in the laboratory. The extensometers recorded no measurable displacements during most of the operation. Two-dimensional, finite-element; three-dimensional, finite-element; and three-dimensional displace-ment discontinuity codes were used to model the area of study. The finite-element models were run with two initial stress conditions, i.e., stress due to gravity only and stress obtained by in situ measurements. Horizontal stresses in the models reduced the calculated factor-of-safety in the mine back by up to a factor of 10, but did not have a significant effect on calculated pillar stability.

Jan 1, 1989

By C. K. Rose

A hydraulic scaling rig was placed in operation at the Bureau of Mines oil-shale mine near Rifle, Colo., in 1953. The rig consists of a self-leveling platform mounted on a hydraulic-powered boom. The boom is mounted on the bed of a diesel truck. The equipment provides a movable work platform from which two men can work in safety and comfort while barring loose rock from the backs and walls of the rooms, pillars, and haulageways. INTRODUCTION As a part of its synthetic liquid fuels program the Bureau of Mines has developed a mine in the richer oil-shale beds of the Green River formation near Rifle, Colo. An important part of the work of the Oil-Shale Mining Branch is investigation of techniques for low-cost mining of oil shale on a commercial basis. It is evident that scaling loose rock from the high backs and walls of the mine represents a portion of the direct mining cost. This paper describes the development of a scaling rig for operation in the upper heading of the mine, which is 39 feet high.

Jan 1, 1954

By Phyllip Worley, Frank E. Chase, Christopher Mark

The Harris No. 1 Mine, located in Boone County, WV, has been longwalling the Eagle Coalbed for over 30 years. Harris has experienced numerous interactions associated with the extensive room-and-pillar and longwall mining operations which have been conducted in the overlying No. 2 Gas Coalbed. The problems have included roof falls, excessive rib sloughage, and gateroad and bleeder entry closure. A detailed evaluation of the multiple seam experiences at Harris No. 1 Mine was conducted as part of the National Institute for Occupational Safety and Health (NIOSH) nation-wide multiple seam mining case history data base. One observation from the Harris gateroad case histories was that smaller, critically loaded, upper seam pillars seemed to cause more severe ground conditions than did wider pillars. The LaModel program was used to investigate this supposition, and the results confirmed that “critical” sized pillars do transmit the highest amounts of stress to adjacent seams. In addition, the data suggest that the probability of a major multiple seam mining interaction increases when the depth of cover is 1,000 ft or greater and when the Eagle seam pillars have a Analysis of Longwall Pillar stability factor less than 1.50.

By John J. Mulligan

The Bureau of Mines sampled a gold-bearing schist series 50 miles east of Nome near Bluff, a dormant mining camp on the southern shore of the Seward Peninsula, Alaska. Gold is unevenly distributed through a section of a schist series that extends from the coast northward 4,500 feet. In this section the schists dip westward 20 to 38 degrees and have an outcrop width of about 1,000 feet and a normal width of about 500 feet. An intensely fractured zone within the schists averages 0.015 to 0.017 ounce of gold and 0.03 to 0.05 ounce of silver per ton for outcrop widths of 200 to almost 500 feet. The grade of the remainder of the schist series ranges downward to scant traces. Gold eroded from these schists collected in solution channels in metalimestones to form the Daniels Creek placers, which also extend from the beach southward under the sea for an unknown distance. The lode sources of the gold placers elsewhere in the southern Seward Peninsula may be similar schists that occupy a similar position in the metasedimentary series.

Jan 1, 1971

By J. H. Jansky, P. W. Jeran, G. L. Hassett, M. C. Irani

This Bureau of Mines report tabulates methane emissions from U.S. bituminous coal mines with daily emission rates of at least 100,000 cfd according to States, counties, and coalbeds. Most of the methane emitted is from mines in the Appalachian States. Total daily emissionin 1975 was 216.3 MMcfd, compared with 227.0 MMcfd in 1971 and 214.5 MMcfd in 1973. Thirty counties in nine States had daily methane emissions of 1 MMcfd or more, These emitted 93 percent of the total methane. The highest emissions were from Monongalia County, W. Va,, which accounted for 18.9 percent of the total. This was followed by Marion County, W. Va., 9.6 percent; Buchanan County, Va., 8.5 percent; Jefferson County, Ala., 6.1 percent; and Washington County, Pa., 5.9 percent. The Pittsburgh coalbed emitted 45.7 percent of the total methane, followed by the Pocahontas No. 3 coalbed with 12.9 percent. The report lists 196 mines, of which 60 had daily methane emissions of 1 MMcfd or more. Included in this compilation are the identification and thickness of the coalbed, methane emission, coal production and ventilation rates, number of drifts, shafts, and slopes used for ventilation purposes, shaft depth, age of mine, and gas-to-coal ratio.

Jan 1, 1975

By E. Morrice

High-purity lanthanum metal was prepared by electrolysis of La003 in a LaF3-LiF-BaF2 bath at 950° C. The requisite bath temperature for the deposition of molten metal was maintained by supplying the heat as current directly to the electrodes. A current efficiency of about 60 percent was obtained. The lanthanum nodules contained carbon and oxygen as major impurities. The total impurity content was from about 0.1 to 0.2 percent.

Jan 1, 1962

By C. Melvin Lepper

To provide the U.S. mining and energy industries with information in the selection of seismic detectors for high-resolution applications, the Bureau of Mines evaluated 35 velocity detectors (geophones) and 9 accelerometers. It was found that velocity detectors with natural frequencies from 10 to 100 Hz were effective for seismic studies in the 5-to 600-Hz spectrum and that accelerometers were most effective in the 100-to 1,000-Hz range. Although the accelerometers described in this report performed about equally with the better velocity detectors tested, the accelerometers showed higher output voltage levels at higher frequencies, which is an advantage. It is important that a seismic detector and its intended purpose be matched properly to achieve the intended results in high-resolution applications. There are many factors that could affect proper matching, thus careful selection of the best detector for a particular application must be exercised.

Jan 1, 1981

By W. A. Cole

This report covers the preliminary phase of an investigation of clays, shales, and certain rocks in Wisconsin to determine the feasibility of processing lightweight aggregate in the State. The study was extended to include rotary-kiln testing of a limited number of shale samples, and to an appraisal of the Maquoketa shale resources in eastern Wisconsin. A total of 45 samples of clays, shales, and other argillaceous rocks of Wisconsin were tested. The lower Maquoketa shale is the only material found to date that offers possibilities as a source of material that can be processed in a rotary kiln for lightweight aggregate. Bedrock occurrences of the Maquoketa shale are found in the eastern and southwestern parts of the State. The populous southeastern region of Wisconsin presents a large potential marketing area for lightweight aggregate. For this reason special study was directed to the Maquoketa shale in the eastern district.

Jan 1, 1961

By R. L. Schmidt

The Methane Control and the Respirable Dust Groups at the Twin Cities Mining Research Center (TCMRC) cooperated recently in obtaining production samples of approximately 1 ton each, from the loading conveyors of a ripper, a borer, and a loading machine in conventional development headings. These samples were sized, in four stages, from plus 4 in to minus 10 µm. The conventional product had the least fines of the three production methods. The borer product had more fines than did the ripper product, but it also had a greater amount of large pieces. All three products, as sampled, had essentially the same amount of minus 10-µm particles. Photomicrographs and surface?-area comparisons were made. Gas -adsorption, surface-area determinations on particles under 37 µm give essentially the same value. Surface-area calculations, assuming spherical particles and no porosity, give a smaller area to the conventional product.

Jan 1, 1972

By S. E. Khalafalla

The Bureau of Mines has used colloidal solutions of magnetite in a magnetic field to segregate nonmagnetic materials such as nonferrous scrap metals and to concentrate precious minerals. Conventional magnetic separation relies on the inherent magnetic susceptibility of the material to be separated and may be designated as magnetic separation of the first kind the medium of separation rather than the separated particles are made magnetizable, a new system of gravity separation results. In this new magnetic separation of the second kind, a magnetic fluid rather than air or water acts as the separation medium. The same force that attracts magnetic objects in separations of the first kind also attracts the entire separation medium in separations of the second kind, thereby creating a reactionary force of equal magnitude in the opposite direction. This force, sometimes called the levitation force, can be made to segregate nonmagnetic particles in a flowing stream according to their specific gravity. The technique has been applied to segregate nonferrous metals from automobile and appliance shredders and mixed scraps. The system has also been used to upgrade diamondiferous jig concentrates from certain river gravels in order to facilitate the sorting and recovery of their diamond content.

Jan 1, 1981

By H. Kim, R. W. Plummer, T. J. Stobbe

"The probability of developing coal workers' pneumoconiosis (CWP) varies among miners in different geographic areas, coal seams, and jobs. Many studies have revealed the correlation between mineral content and the frequency and severity of CWP development still remains controversial. Furthermore, the mineral content and its variability in different areas is unknown.Since mineral content is expected to vary from location to location within a mine, between mines, between coal seams, and over time, this information will be valuable in understanding the variations in CWP incidence, as well as in establishing the appropriate kinds of dust to use in toxicological research programs studying CWP.Size-selective airborne dust samples were collected using 4-stage cassette impactors at 9 different locations in each of five coal seams. These coal seams were the Upper Freeport, Pittsburgh, Kittaning, Coal Burg, and Pocahontas. Mineralogical analyses were done by a x-ray powder diffraction photographic technique.Common minerals found in coal mine dust were illite, calcite, kaolinite, quartz, siderite, dolomite, gypsum, anhydrite, and pyrite. The distribution of minerals in interand intra location samples will be reported. Early results on the mineral content show wide variations between locations.in a mine and between coal seams, and small, but significant, variations between particle sizes.INTRODUCTIONIn spite of its long history of incidence, and the large amount of research conducted on it, coal workers' pneumoconiosis (CWP) is still prevalent among coal miners and needs further research to develop effective preventive and remedial measures. Although the dose-response relationship between simple CWP and coal mine dust has been established (1), the causal agent(s) and the mechanism(s) involved in the progression of simple to complicated CWP are not yet defined. Many plausible hypotheses have been made to explain the mechanisms involved in the disease progression however none of them is satisfactory. In addition, the source of variation in occurrence of CWP among miners in different geographic areas (2), rank of coal seam (3,4), and job (5) remain unsolved."

Jan 1, 1988

By J. J. Demeter

Anthracite from the four producing regions in Pennsylvania was both ashed in the laboratory and burned on a chain-grate stoker to determine the sulfur-retention properties of its ash. The retention of sulfur in laboratory-prepared anthracite ash was shown to be related to ashing temperature and to the amounts of sulfur and calcium present in the coal. At the usual laboratory ashing temperature of 750° C sulfur retention ranged from 0.8 to 13.2 percent of the total coal sulfur. Sulfur retention in the ash was negligible, o to 0.3 percent, at 1,200° C, which is the thermal decomposition temperature of calcium sulfate; thus calcium sulfate does not form and cannot serve as a sulfur-retaining agent. In several tests the anthracite was mixed with 6 or 10 percent dolomite prior to firing in the chain-grate stoker. The dolomite did not improve sulfur retention owing to the high temperature in the fuel bed. Sulfur retention was, however, related to the unburned carbon in the ash. The relationship of the percentage of original coal sulfur retained in the ash (Y) to the percentage of the original carbon in the coal remaining in the ash (X) is expressed by Y = -0.579 + 0.914X. The percentage of sulfur retained is almost directly proportionate to the percentage of original coal carbon in the ash.

Jan 1, 1968

By John J. Henn

An evaluation is presented for an ammonium sulfate leaching process designed to extract manganese from Cuyuna, Minn., and Aroostook, Maine, deposits. In this process the manganese and iron in the ore are reduced to MnO and Fe 3 0 4 in a shaft furnace; the reduced ore is then leached with ammonium sulfate solution forming soluble manganous sulfate while leaving most of the iron undissolved. After filtration, the manganese and some impurities are precipitated from solution as carbonates which are then pelletized and calcined to form a product composed mainly of Mn3O4. The plants are designed to produce 100 tons per day of manganese contained in a product that is suitable for the production of ferromanganese. A byproduct credit, together with the extra processing cost, is included for the Cuyuna ore processing plants because Fe2O3 may be recovered for use in blast furnaces. The estimated operating costs per ton of manganese, excluding income taxes and return on investment, are: [ ] The process with or without byproduct recovery, when treating Cuyuna or Aroostook ores, is not economically competitive with ores available at $71.43 per ton of contained manganese.

Jan 1, 1968