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By H. G. Iverson

Solid state reactions of manganese with silica were investigated in high-temperature tests. Reactions of 0.5 to 4.0 moles manganese (Mn) with 1 mole silica (SiO2) at 1,100° C and of 2.0 Mn:SiO2 mole-ratio mixtures at 1,000° to 1,150° C yielded products consisting of a slag phase and a metallic phase. At 1,100° C, the slag phase from reactions of the low Mn:SiO2 mole-ratio mixtures was composed of SiO2 and rhodonite (MnSiO3), and the slag phase from the high Mn:SiO2 mixtures was composed of MnSiOs and tephroite (Mn2SiO4). The metallic phase from the corresponding low Mn:SiO2 mole-ratio reactants consisted of two manganese silicides, Mn5Si3 and Mn3Si; from the high Mn:SiOg mixtures, it was Mn and the manganese silicide (Mn5Si). For the higher mole ratios of MnSiO2 the manganese content in the metallic phase increased, while the manganese and silica contents of the slag phase remained nearly constant. The slags did not contain free or uncombined manganese oxide (MuO). For the 2.5 to 4.0 Mn:SiO2 mole-ratio mixtures reacted at 1,100° C, the maximum quantities of silica reduced and of the manganese in the slag appeared to become asymptotical at about 41 and 48 percent, respectively. A brominating procedure was developed that was highly selective in removing the metallic constituents from the reaction product, leaving the slag phase as residue. X-ray diffraction patterns were obtained on prepared silicides Mn5Si, Mn3Si, and MnSi.

Jan 1, 1967

By Lee J. Raabe

A specialized loading system for tensile and fatigue testing of wire rope was constructed and installed in the U.S. Bureau of Mine Wire Rope Test Facility in Bruceton, Pennsylvania. The computer-controlled closed-loop servo-hydraulic test system which can apply up to 800,000 pounds of force on the rope while stretching it up to 30 inches will be used in the development and verification of hoist rope retirement criteria for ropes in the 1 to 2 ½ in. diameter range. Characteristics and capabilities of the system are discussed.

Jan 1, 1984

By James H. Gary

Data regarding the composition and physical properties of Florida land-pebble phosphate-waste slime are presented, and the feasibility of dewatering and beneficiating the slime by several different methods is discussed. Chemical analyses, electron micrographs, and X-ray diffraction data showed that principal constituents of the slime included quartz, attapulgite, and flaorapatite. Viscosity of the slime changed with pH; thixotropic, Newtonian, and rheopectic states were observed as the pH increased. Use of various flocculating agents was not effective in improving thickening properties of the slime. Dewatering tests using pressure filtration showed that temperature influenced the filtration rate more than pressure; the filtration rate at 165° C was tenfold that at room temperature. Selective flotation of the slime, using two different processes, gave promising results. About 25 pct of the phosphate was recovered in a concentrate assaying 31 pct P205, Other tests demonstrated that the slime could be successfully fractionated at 20-microns using a hydrocyclone. In hydrometallurgical tests about 80 pct of the phosphorus and alumina were chemically extracted from the slime using sulfuric acid. Limited bacteriological studies made of the slime showed that several types of microorganisms were present and grew in the material despite the presence of fluorine-bearing minerals.

Jan 1, 1963

By Tuncel M. Yegulalp

This final report contains the results of all work performed under BOM Grant J0333905. A preliminary systems analysis of coarse-particle coal slurry pipelines as a haulage method for longwall mining systems was performed. Two exhaustive literature surveys on state-of-the-art longwall mining and slurry transport technologies were prepared. Two representative longwall systems were designed, one with conventional haulage and one with slurry haulage. These two systems were then compared on the bases of cost, safety, and reliability. The conclusions were that for the case of a two-face longwall mine, a coarse slurry transport system does not have a clear-cut cost advantage over a conventional (conveyor-hoist) system. However, indications were that a cost advantage could occur under different analytical conditions such as: (1) a larger scale mine, (2) if intangible benefits were quantified, and (3) if new generation technology rather than currently available technology were applied to the study. Budget and time constraints prevented exploration of these conditions.

Jan 1, 1982

By M. K. Quinn, N. P. Reddy, A. W. Khair

"An analysis of coal fragmentation due to the action of a continuous miner is presented. Underground coal cutting by a drum-type continuous miner was simulated in the laboratory using a specially designed unique automated rotary coal cutting simulator (ARCCS). The rotary coal cutter provided the versatility of varying the operating and in-situ parameters to provide information on the effects of generating 37 pm (0.0015 in) particles. In these tests, coal blocks with an approximate dimension of 50.8 x 35.6x 20.32 cm (20x 15x 8 in) were first subjected to confining pressures equivalent to in-situ conditions. The blocks were then cut by the rotary cutting head of the ARCCS, thus simulating the action of the continuous miner in underground coal mining. During the tests under a particular set of in-situ and operating parameters a number of other parameters such as (1) penetration of bit into coal, (2) penetration resistance (thrust and cutting pressures), (3) rotating velocity of' cutting head, and (4) acoustic emission activity in the coal block were monitored. During the test, all the cut products were collected for size distribution analysis. After each cutting cycle the fractured surfaces were photographed and a velocity survey was conducted using a sonic technique. At the end of each experiment the cutting paths of the bits in coal were photographed using a camera attached to an optical microscope.The results led to a better understanding of the mechanisms of the fragmentation process during coal cutting and the effect of operating parameters, in-situ conditions and coal type on the size distribution of the cut product:"

Jan 1, 1989

By J. S. Browning

The Bureau of Mines investigated the concentration characteristics of high-clay sylvinite ores from potash companies operating in the Permian basin near Carlsbad, N. Mex. These ores, containing 14 to 19 percent K20 and 3 to 5 percent clay slimes, cannot be effectively processed by current commercial flotation methods because of their high clay content. A solution to this problem was shown to be the use of two-stage moderate scrubbing conditions for clay disaggregation and removal as opposed to strenuous attritioning. Bench-scale beneficiation techniques for recovering potash minerals by flotation from the scrubbed material resulted in acceptable product grades and recoveries. By using a coarse grind, emphasis was placed on production of premium granular and coarse products. Flotation results showed that concentrates of 59.6 to 60.4 percent K.0 values can be obtained. Continuous pilot plant beneficiation techniques for recovering potash minerals by flotation resulted in concentrates containing 58.8 to 59.8 percent K20 with recoveries of 69.7 to 81.4 percent of the K20.

Jan 1, 1975

By Charles Findlay, Stephen Krickovic, J. E. Carpetta

As one of its projects for degasification of major panels of coal prior to mining within them, the Bureau of Mines conducted methane emission studies during development of a set of three headings 1,800 feet in a major coal panel (2,700 by 3,500 feet) which had been completely isolated by sets of main headings for 12 months in the Federal No. 2 mine (Pittsburgh coalbed) in northern West Virginia. Similar emission studies were conducted in the development of two sets of main headings in virgin coal areas nearby. Comparing the two sets of data indicated that the isolated coal panel had been degasified by approximately 70 percent.

Jan 1, 1973

By R. B. Schluter

The objective of this Bureau of Mines investigation was to determine the effects of adding manganese compounds and ores to iron ore pellets. Manganese dioxide, carbonate, sulfate and chloride, plus six manganiferous ores from the Minnesota Cuyuna Range were tested as additives to increase the manganese content of iron ore pellets. One to 5 percent manganese, as a compound or ore, was added to five magnetite concentrates and one hematite concentrate. These concentrates were ballad, indurated (1,300° C), and tested for reducibility. Manganese sulfate and chloride were unsatisfactory additives causing cracking and degradation of the pellets during reduction. Manganese dioxide, carbonate, and the ores were satisfactory additives. The additives increased pellet compression strengths with a corresponding loss of reducibility, as compared to the pellets without manganese additions. The changes in compression strengths and reducibility were caused by the formation of Jacobite spinel and slag within the pellets. However, when the induration temperature was lowered from 1,300° to 1,200° C the reducibility and compression strengths were comparable to the pellets without manganese additions indurated at 1,300° C.

Jan 1, 1974

By N. S. Dalal, J. F. Mega, X. Shi, V. Vallyathan

Several studies have suggested that pulmonary toxicity to asbestos and silica may be mediated through oxidant-induced cell injury. We have reported recently that surface radicals associated with freshly fractured silica may be an imponant factor in cell injury and induction of pulmonary disease. Although the generation of oxygenated radicals in dust-cell interactions has been demonstrated, there are no data correlating the toxicity of a dust with the level of oxygen radical generation by the dust during its interaction with phagocytic cells. In the present study, we have investigated the in vitro generation of oxygen free radicals from human neutrophils and rat alveolar macrophages stimulated with freshly fractured silica, aged silica, amosite, crocidolite, chrysotilc, and a nontoxic dust, barite. Electron spin resonance (ESR) with the aid of a spin trap phenyl-N-ten-butyl nitronc (PBN) was used to measure the oxygen radicals generated during phagocytosis of the dusts. The relative toxicity index and ESR peak heights, on an equal surface area basis and normalized to barite as one, showed a direct relationship. The normalized toxicity indices and peak heights were: silica, 3.5 versus 2; chrysotile, 4 versus 2; crocidolite, 11 versus 8; and amosite, 26 versus 13. Addition of hydroxyl radical scavengers such as catalase, dimethyl sulfoxide, 1,3 dimethyl-2-thiourea (DMTU), sodium benzoate, and mannitol prevented the radical generation. Carmustine, a glutathione reductase- glutathione peroxidase inhibitor, caused a 5-fold increase in the radical generation. These results indicate that a nontoxic dust such as barite generates toxic oxygen radicals at a minimal level that can be quenched by the normal cellular defense system. For toxic dusts such as silica, amositc, chrysotile, and crocidolite, the potential for oxygen radical generation is enhanced by their surface propenies, physical dimensions, and the surface-based radical-generating redox sites. The enhanced radical generation may impair the cellular defense system, resulting in cell injury. Use of scavengers, chelators, and potentiating agents suggests the membrane-based oxidase system as the probable primary source of the radical-generating system. The data presented herein suggest the generation of oxygen free radicals as an important primary event in silica- as well as asbestos-induced cell injury.

Mar 1, 1992

By Donna L. Anderson

This information circular documents the status of a laser-based guidance system to track and control the tramming maneuvers of a continuous mining machine. The work is part of a multiple project effort at the U.S. Bureau of Mines to develop technology for computer-assisted mining systems. The system includes stationary offboard laser-scanning sensors that report the angular coordinates of retroreflective targets on the mining machine. A microcomputer system processes the angular coordinates, determines position and heading, handles requests for data, and controls tram maneuvers of a continuous mining machine. This report describes the hardware for the sensor and computer systems and the software algorithms for continuous miner position and heading determination, closed-loop tramming, and data request handling. Improvements made to the system since previous documentation include the rewriting of the software on a stand-alone real-time microcomputer system, the implementation of real-time programming techniques, the use of a new version of the laser sensor, and the design and development of explosion-proof enclosures for the lasers and corresponding power supply.

Jan 1, 1991

By V. E. Edlund

Laboratory batch flotation tests were conducted on copper converter slags to evaluate the relative merits of recovering copper from slow-cooled versus water-quenched slags. Three slags containing 1.6, 5.0, and 6.6 percent copper were used. More than 90 percent of the copper was recovered in a rougher concentrate leaving a 0.2- to 0.3-percent copper tailings when treating slow-cooled slag. Lower recoveries and higher copper tailings ranging from 0,5 to 0.6 percent copper were obtained from quenched slag. Grindability studies were made on the respective heat-treated slags. Quenched slags proved more difficult to grind than slow-cooled slags. Cost studies showed that (1) the cost of slow cooling and crushing off-sets any advantages of higher copper recoveries from slow-cooled slag, and (2) water-quenched slag, which requires no crushing preparatory to grinding, could be treated more economically. Costs based on processing 1,000 tons of slag per day would be $1.85 per ton for quenched slag versus $2.37 per ton for slow-cooled slag.

Jan 1, 1971

By N. R. Dixon

This report summarizes all work performed under U.S. Bureau of Mines Contract No. J0395028, "Noise Control of Rubber-Tired Front-End Loaders Used in Surface Mining. " Two loaders, a Caterpillar 988 and an International H-400B, were chosen for this program, and the noise sources and acoustic paths that contribute to the operator's noise exposure were identified. Retrofit noise control treatments were designed and installed on these loaders, and noise reductions of more than 10 dBA at the operator position were achieved on both machines. The retrofit packages are low cost and have been field tested in two mines for more than two years. The results of the program were communicated to the mining industry through a series of noise control workshops and a field manual. The workshops were given in nine states across the U.S. and more than 440 manuals were distributed An audio/visual slide presentation was also developed which the program.

Jan 1, 1983

By Jr. Jacobson

Thermal reactions of l-methylpyrrole, l-butylpyrrole, and l-isopropyl-pyrrole were investigated by a flow method in the temperature range of 4500 to 5750 C. Those of I-butylpyrrole and l-isopropylpyrrole were also investigated in the 3400 to 4000 C range in a static system. The I-substituted pyrroles isomerize by an irreversible reaction to 2-substituted pyrroles. A reversible isomerization reaction shifted the alkyl group from the 2-to the 3-position on the pyrrole ring. All of the isomerization reactions are homogeneous, unimolecular, nonchain, first-order reactions having similar mechanisms and transition states. There is decomposition and cleavage of the longer alkyl side chain when it is in either the 2-or 3-position giving, as products, pyrrole, 2-and 3-methylpyrrole, 2-and 3-ethylpyrrole, pyridines, and hydrocarbons. The decomposition reactions appear to be by free-radical mechanisms. Pyridine homologs are formed by the expansion of the alkylpyrrole: butylpyrrole produces pyridine, and isopropylpyrrole produces 3-methylpyridine. Approximate Arrhenius equations are given for the formation of the decomposition products.

Jan 1, 1966

By Manuel Gomez

Areal distributions for ash, total sulfur, and sulfur forms were developed for the top 12 inches, the middle section, the bottom 8 inches, and the total seam of Pittsburgh coal in southwestern Pennsylvania. The sulfur and ash exhibit an apparent high local variability. As a general rule, both the sulfur and ash show high concentrations in the top 12 inches and in the bottom 8 inches of the seam relative to the concentrations observed in the middle section of the seam. The high-low sulfur and ash concentrations in the top 12 inches of the seam are not coincident with the high-low sulfur and ash concentrations in either the middle section or the bottom 8 inches of the seam. With respect to sulfur and ash, it is suggested that the top and bottom sections of the Pittsburgh coal may reflect both a syngenetic and epigenetic origin. Present data support the belief that paleotopography controlled Pittsburgh seam deposition. Evidence is presented to show that channels were cut at various times into the semilithified sediments that buried the Pittsburgh seam. In this channeling process, portions of the Pittsburgh coal may have been eroded away. Following channel development, the lower part of the Pittsburgh sandstone filled the complex system of braided channels to produce the "want areas" encountered in present mining operations. In localized areas of the Pittsburgh seam, impingement of Pittsburgh sandstone may be responsible for the lateral displacement of the coal. Information of this type becomes important in the assessment of exploration data, in the development of a quality control system for mine output, and in mine life planning.

Jan 1, 1974

By William I. Nissen, Richard Havens

Continuous flotation studies were made at a 50 - lb - per - hr feed rate to confirm the effectiveness of a batch - scale procedure for concentrating phenacite and bertrandite minerals from Mount Wheeler ores that contained , in percent , 0.47 , 0.78 , and 4.7 BeO . The procedure for selective froth flotation of the beryllium minerals from a gangue composed chiefly of calcite , fluorite , and mica comprised closely controlled preconditioning with sodium fluoride and sodium hexametaphosphate in a series of small mechanically agitated tanks and use of a mixture of oleic acid with kerosine , fuel oil , or turpentine as a collector . It was difficult to adapt the laboratory flotation procedure to continuous operation . The principal problem of achieving adequate conditioning to depress calcite and fluorite ultimately was resolved by conditioning in series . Thereafter , three ore samples of different grades treated on a continuous basis yielded concentrates containing from 12 to 25 percent Beo from these relatively complex and difficult ores . Recoveries , on a BeO basis , ranged from 75 to 88 percent . Losses , which primarily were due to incomplete liberation , probably could be lowered in a commercial operation .

Jan 1, 1964

By H. F. Yancey

The development, manufacture, and sale of small coal stokers suitable for domestic use has provided a new industry in the United States at a time when badly needed. Sales of domestic stokers have doubled each year for the past 4 rears, until in 1936 probably more than 90,000 such units were put into use. According to reports of the Bureau of the Census 79,543 residential stokers were sold in the first 10 months of 1937 by 109 manufacturers. This rapid expansion has made itself felt in the coal-mining industry. The smaller sizes of coal, either in a sized or slack condition, are in greater demand; as a result, preparation practices at the mines have had to be revised so that, in many instances, lump coal is being crushed to meet the demand for stoker coal. This situation in turn has necessarily resulted in a realignment of price schedules for the different sizes. One of the first underfeed stokers small enough for domestic use was developed at Seattle, Wash., in 1912; in 1916, a small overfeed stoker was developed at Seattle. These two types are generally considered to represent the beginning of the present domestic stoker industry in the United States. A careful inquiry as to the number of domestic stokers now installed in the Seattle area, made by C. R. Pate, who was detailed to this duty by the Works Progress Administration, indicated that probably 7,000 domestic stokers are being used in this area for residential heating. Most of these stokers axe of the overfeed type, although in the past 2 years the underfeed type has made rapid gains.

Jan 1, 1938

By Robert H. Ridgway

This paper presents the results of the second in the series of annual canvasses on the consumption of ferrous scrap and pig iron in the United States, inaugurated in 1935 by the Bureau of Mines and published in Report of Investigations 3329. The study was undertaken in response to requests from trade organizations and others for detailed statistics on this phase of the iron and steel industry. Thus, for the first time, producers, buyers, sellers, and consumers of iron and steel scrap have had an accurate statistical picture of this important raw material As originally contemplated, the study was to be continued on an annual basis, but, owing to budgetary limitations for the fiscal year 1937-38, the Bureau may be unable to conduct the canvass for 1937.

Jan 1, 1937

By H. F. Yancey

The development, manufacture, and sale of small coal stokers suitable for domestic use has provided a new industry in the United States at a time when badly needed. Sales of domestic stokers have doubled each year for the past 4 years, until in 1936 probably more than 80,000 such units were put into use, According to reports of the Bureau of the Census 75,543 residential stokers mere sold in the first 10 months of 1937 by 108 manufacturers. This rapid expansion has made itself felt in the coal-mining, industry. The smaller sizes of coal, either in a sized or slack condition, are in greater demand; as a result, preparation practices at the mines have had to be revised so that, in many instances, lump coal is being crushed to meet the demand for stoker coal. This situation in turn has necessarily resulted in a realignment of price schedules for the different sizes. One of the first underfeed stokers small enough for domestic use was developed at Seattle, Wash., in 1912 in 1916, a small overfeed stoker was developed at Seattle. These two types are generally considered to represent the beginning of tie present domestic stoker industry in the United States. A careful inquiry as to the number of domestic stokers now installed in the Seattle area, made by C. R. Pate, who was detailed to this duty by the Works Progress Administration, indicated that probably 7,000 domestic stokers are being used in this area for residential heating. Most of these stokers axe of the overfeed type, although in the past 2 years the underfeed type has made rapid gains.

Jan 1, 1938

By John H. Hild

The topography of the Jamestown fluorspar area is rough and ranges from 6,400 to 8,000 feet in altitude. Some fluorspar was mined as early as 1870, but mining really did not begin in earnest until 1940, and up to July 1947 it is estimated that 272,500 tons of fluorite was mined and milled. In 1947 the General Chemical Co. was mining fluorite and milling it in a 200-ton-a-day mill at Valmont, 7 miles east of Boulder, and the Ozark-Mahoning Co. was milling ore in a 100-ton-a-day mill at Jamestown, using ore mined, by H. M. Williamson & Son. These fluorite deposits comprise veins in a granite country rock. The Bureau of Mines drilled eight holes, aggregating 2,579.1 feet, on the Blue Jay vein; four holes, aggregating 1,434 feet, on the Chancellor; and one 350-foot hole on the Nations Treasure. Fluorite of a minable grade and width was found in 10 of the holes drilled. In this report the location and accessibility, physical, features and climate are described and a brief history of the district is given. The deposits and character of the ore and sampling and analyses are described, mine workings are outlined, and work performed by the Bureau of Mines is summarized. Diamond drill logs are shown in appendix I, and 'Sample analyses are tabulated in appendix II.

Jan 1, 1949

By Robert K. Koch, Henry E. Blake

Laboratory tests were made to determine if aluminum fluoride of commercial grade could be synthesized by reacting alumina hydrate with dilute ( 25 to 75 grams per liter of fluorine ) aqueous fluoride solutions . • Products containing up to 90 percent aluminum fluoride ( A1F ) were synthesized by reaction of alumina trihydrate ( A120 3H2O) with either dilute hydrofluoric acid ( HF ) or ammonium fluoride ( NHF) solutions , the ammonium fluoride solution resulting from ammonia ( NH ) desilication of a hydrofluoricfluosilicic acid ( HF - H₂ SiF ) solution . Fluorine recoveries of over 80 percent were obtained with either type of solution . The hydrated precipitates of AlF, and ( NH4 ) , A1F ( ammonium aluminum fluoride ) obtained by reacting hydrated alumina with these solutions were subsequently converted to anhydrous AlF, by controlled heating .

Jan 1, 1964