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By Richard S. Olsen

Prior work by the Bureau of Mines demonstrated a feed preparation method that eliminates the formation of slime during leaching of calcined kaolinitic clay and makes leached residues fast settling and easy to filter. Nitric acid leaching rates determined for calcined kaolinitic clay prepared by this method were found to correspond to a zero-order reaction model for both batch and continuous, stirred-tank leach-ing. A rate constant of 0.136 min-1 was determined. Separation of solid residues from the reacted slurry was examined, and filtration rates were determined. Permeabilities of the flocculated, leached residues were around 51 darcys, or 5.0 x 10-7 cm2 for laminar flow through 4-ft-deep beds.

Jan 1, 1983

Improve the performance of waterjet nozzles used for water-jet-assisted cutting to optimize rock cutting efficiency. Approach The performance of a longwall shearer equipped for water-jet-assisted cutting was evaluated during an earlier study (Tech News No. 277). Waterjet nozzles were used to direct the solid streams of water that impacted the rock near the tip bits. The maximum water pressure that could be delivered to the nozzles was about 6,000 psi. Due to the "break up" of the solid stream of water, some of this pressure was lost before the water reached the rock. The pressure could have been increased by moving the nozzle closer to the bit tip but) moving the nozzle too close increases the possibility of damage to the nozzle. Study Results A test apparatus was built to measure water pressure at the location of water jet impact (see illustration). The target, a tungsten carbide plate with a 0.013 inch diameter orifice, was placed at the location of water jet impact. A pressure transducer, used to monitor impact water pressure, was positioned under the plate. Water pressure at the nozzle was maintained at 6,000 psi. The distance between the nozzle and target was varied from 2 to 5 inches.

Jan 1, 1988

By W. W. Adams, T. D. Lawrence

The National Safety Competition , a safety contest conducted annually by the Bureau of Mines , United States Department of the Interior , to promote safety at mines and quarries , has just resulted in the award of safety trophies , known as the " Sentinels of Safety" , for 1939. Awards were made to a bituminous- coal mine in Wyoming , an anthracite mine in Pennsylvania , a metal mine in Michigan , and a nonmetallic -mineral mine in Alabama ( all being underground mines ) and to anopen-cut mine in Minnesota and a stone quarry in Michigan. The awards signify that the recipients won first place in their respective groups in an accident-prevention contest by operating during 1939 with the smallest loss of time in proportion to the total number of man-hours worked at the mine or quarry . Each of the trophy-winning companies for 1939 operated his property without a disabling injury to an employee , except at the anthracite mine , whose record , while not free of accidents , was better than that of any other mine in the anthracite group . The " Sentinels of Safety" trophy is a bronze statue of a mother and infant welcoming the father safely home after his day's work in the mine . Six trophies were provided by THE EXPLOSIVES ENGINEER magazine to be awarded annually by the Bureau of Mines . These trophies remain in the custody of the mining companies for 1 year , after which the trophies are transferred to the winners of the succeeding year's contest . A replica of the trophy is provided for permanent retention by the company surrendering the bronze trophy . In addition to the award of the safety trophies for 1939 , each man employed at a winning mine or quarry receives from the Bureau of Mines a certificate of honor in recognition of his part in helping his company to win the trophy . Companies ranking second , third , fourth , or fifth in their respective groups , and all mines and quarries whose records were free of disabling ( losttime) injuries and showed at least 30,000 man-hours worked during the contest year were awarded certificates of honorable mention . Mines and quarries that won the " Sentinels of Safety" trophies for 1939 and those that were awarded certificates of honorable mention are indicated in the following paragraphs .

Jun 1, 1940

By D. H. Baker

This report, one of a series prepared by the Federal Bureau of Mines on the technology of titanium, describes the development of an electrorefining cell from which cathode deposits up to 30 inches long can be produced. Data show individual deposits to be homogeneous, comparable from top to bottom, and not varied in quantity or quality of metal over the entire length of the deposit. Investigations concerned with various diameter cathodes showed that cathode current efficiencies were materially reduced with cathodes less than 2 inches in diameter. Deposits produced on 1/2-inch-diameter cathodes showed cathode current efficiencies of 19 percent and on 1-inch cathodes, just over 22 percent, whereas deposits produced on 2- and 4-inch-diameter cathodes showed about 70-percent current efficiencies. A series of 20 deposits on 4-inch-diameter cathodes was produced under simulated production operation. The average current efficiency, based upon a divalent ion, was 72 percent with 11 1/2 pounds of metal produced per cycle of operation - 98.8 percent of which had a Brinell hardness number (B.h.n.) of 80 or less.

Jan 1, 1959

By W. W. Adams

luring the past two years the Bureau of ?,lines has been receiving from 100 to 150 coal mines in various States a report of each accident causing death, permanent total disability, permanent partial disability, or temporary disability lasting beyond the remainder of the day or shift on which the accident occurred. For each 100 accidents in these groups, there are perhaps from 35 to 45 accidents that do not disable the employee beyond the remainder of the day, and of these fraction-of-a-day accidents the Bureau has compiled no statistics. Information revealed by the reports is to the effect that falls of roof and coal in bituminous coal mines are responsible for 28 per cent of the temporary injuries to underground workers and 33 per cent of the days lost from all temporary injuries underground; they also indicate that falls caused 59 per cent of the deaths from all causes underground. Figures compiled by R. N. Hosler, of the Pennsylvania. Mine Rating Bureau, and covering accidents in bituminous; minis in that State, chow that 61 per cent of the deaths underground during the years 1917-1921 wore due to falls. Neither of these percentage figures includes deaths in major explosions; figures for all bituminous mines in the United States during the five years 1920-1024, inclusive of deaths in major explosions, show that 52 per cent of the deaths underground and in shafts were due to falls of roof and coal.

Jan 1, 1925

By Eugene T. Sheridan

The Bureau of Mines annually canvasses the peat producers in the United States and publishes economic data on the industry, based upon reports from producers. This publication lists all producers that reported commercial production to the Bureau for 1959. The companies named herein represent virtually all commercial producers of peat. A few companies, however, may not have been canvassed or failed to respond, as tine survey is voluntary For producers, arid the industry has many small operations that operate intermittently. No consideration was given to the quantities of peat produced and output of the various companies listed ranged from less than 100 tons to more than 50,000 tons, Peat is included in the Bureau's annual surveys of the mineral industries because, technically, peat is a fuel. Although none is used for fuel in the United States, peat is a potential source of energy and one of our large mineral resources. The domestic peat industry produces peat chiefly for use as a soil amendment. The industry has expanded rapidly during the past decade with active operations increasing from 45 in 1947-49 4/ to 105 in 1959. Output during this period has increased 218 percent, rising from 131,782 net tons to 419,460 net tons.

Jan 1, 1960

By F. N. Kissell, C. H. Elder, C. M. McCulloch

The applicability of the "direct method" for determining the methane content of virgin coalbeds was tested. Preliminary results indicate that the direct method, when applied to exploration cores, can be successfully used to estimate coalbed gas content and also approximately predict the total gas emission from a prospective mine located in the coalbed at the exploration site.

Jan 1, 1973

By Wallace E. Anable

This investigation by the Bureau of Mines was conducted chiefly on Cuban serpentine nickeliferous ores to determine whether these materials would be amenable to direct carbothermic reduction in an electric furnace to produce a low-carbon ferro-nickel. The project was carried out as one of several under a Memorandum of Agreement between the Bureau of Mines and the General Services Administration (Contract GS-OO-B (D)-152l). Two ore samples were received for this investigation. One was a mixture of nickeliferous serpentine from the North Ocujal, South Ocujal, and San Juan claims of the Nicaro Nickel Co. The other sample was a mixture of material from the Ramona and the Lorna Mulo claims of the Cuban Nickel Co. Most of the ore from the Ocujal-San Juan deposits and about 40 percent of the sample from the Ramona-Lorna Mulo deposits were calcined before smelting. The remainder of the sample from the Ramona-Loma Mulo deposits was smelted after drying to about 8 percent moisture. An arc-resistance, selective-reduction smelting technique was employed in these tests. Either bagasse alone or a mixture of bagasse and coke was used for reductants. No flux was used in the furnace charges.

Jan 1, 1957

By M. D. Schlesinger

Experimental data for coal hydrogenation are presented to show that when a vehicle oil produced from coal is present, coal is hydrogenated to the same high conversion whether molybdenum catalyst is impregnated on the coal or intimately mixed with the slurry. Differences in product distribution could be related to the severity of operating conditions. No minimum mixing time was established, but 2 hours was sufficient. Longer periods of mixing, to 14.75 hours, had no effect on the results. The hydrogenation conditions were in the pressure range of 8,500 to 10,000 p,s,i. at 400° to 500° C. Most of the experiments were made in duplicate. The results were obtained with molybdenum concentrations of 0.01, 0.1, and 1 percent. Al the mentioned pressure range and a time at temperature of 15 to 60 minutes, coal conversions higher than 98 percent were obtained.

Jan 1, 1962

By V. A. Danielson

The Bureau of Mines examined sources, consumption, and movement of iron and steel scrap in the southeastern States--Alabama, Florida, Georgia, Kentucky, North Carolina, South Carolina, and Tennessee. Officials of the scrap-processing and scrap-consuming industries were interviewed, data was obtained from the published literature, and a canvass was made by the Bureau of scrap consumers. The Southeast generated excess scrap which was shipped to domestic and foreign consumers in about equal proportion. Total 1963 demand in the Southeast was 3,336,000 net tons, of which purchased scrap was 75 percent, foreign exports 13 percent, and domestic exports 12 percent. Alabama, with 47 percent of the purchased scrap consumption in 1963, was the most important scrap-consuming State, and Kentucky, with 34 percent, was the second most important one. Southeast demand was 4.8 per-cent of the total U.S. demand. Projected 1980 consumption is 8,340,000 tons. Scrap prices showed a slight downward trend for the period 1953-63, although gross consumption increased slightly. A significant trend in processing scrap in the Southeast is the preparation of smaller bundles or "briquettes" weighing from 75 to 150 pounds, which are easier for consumers to handle and inspect. Another significant development is the "shredding" of automobile scrap which produces a dense, clean scrap especially desirable for use in electric furnaces.

Jan 1, 1967

By C. P. Haller, S. J. Aresco, R. F. Abernethy

The Bureau of Mines has been active in promoting the purchase of coal for Government use under specifications that define the requirements in terms of heating value of the coal, expressed in British thermal units, and the composition as shown by proximate analyses. To these, when required, are added the ash- softening temperature of ash, the free-swelling index, and the hardgrove grind- ability index. Under most of these specification contracts the bidders guarantee the quality of the coal, and that guaranteed by the successful bidder becomes the standard of his contract. The deliveries are sampled in accordance with instruc- tions issued by the Bureau of Mines; the samples are analyzed in the Bureau laboratory to determine whether the coal is of the quality guaranteed by the con- tractor and, if it is not, a price adjustment is made. Analyses of the delivered coal and tipple samples (samples collected at mine tipples as coal is being loaded into railroad cars or trucks) provide valuable data for use in evaluating future bids. In addition, the continuous sampling of coal as delivered is a check on the practical results obtained in burning the coal. The Government purchased approximately 5-1/4 million tons of coal in fiscal year 1953. In connection with these purchases, the Bureau analyzed 11,435 samples. These are published for the use of Government officials and the public. A series of publications has been completed on coal analyses by States, or, where production is small in any one State, by groups of adjacent States. In addition to analytical data showing composition and quality of coals of the States, the publications con- tain brief descriptions of the geological structure of the coal basins, typical mining conditions in the various districts, the principal economic data of the industry, and the relationship of mine or channel samples to delivered and tipple samples. The present publication covers many States but deals only with the analytical data of the coals. Previous publications in this series are: Bulletin 516, Analyses of Tipple and Delivered Samples of Coal (Collected During the Fiscal Years 1948 to 1950 Inclusive); Report of Investigations 4934, Analyses of Tipple and Delivered Samples of Coal (Collected During the Fiscal Year 1951); Report of In- vestigations 4972, Analyses of Tipple and Delivered Samples of Coal (Collected During the Fiscal Year 1952). Following are the Bureau of Mines technical papers published by States, with their numbers: Alabama, 347; Alaska, 682; Arizona, California, Idaho, Nevada, and Oregon, 696; Arkansas, 416; Colorado, 574; Illinois, 641; Indiana, 417; Iowa, 269 and 706; Kansas, 455; Kentucky, 308 and 652; Maryland, 465; Michigan, North Dakota, South Dakota, and Texas, 700; Missouri, 366; Montana, 529; New Mexico, 569; Ohio 344 (and Bulletin 499); Oklahoma, 411; Pennsylvania Bituminous, 590 (Supplement 645); Pennsylvania Anthracite, 659; Tennessee, 356 and 671; Utah, 345; Virginia, 365 and 656; Washington, 491 (Supplement 618); West Virginia, 405 and 626; and Wyoming, 484.

Jan 1, 1955

By R. V. Lundquist, H. Leitch

The solubility characteristics of three calcium aluminates , 12Ca0 · 7A120½ 3Ca0 A1203 , and 4Ca0 A12 03 Fe2O3 , were determined in water and in solutions of NaOH and Na₂ CO₂ to more clearly define their role in relation to the recovery of aluminum by the lime sinter and the lime - soda sinter processes . The calcium aluminates were prepared by sintering stoichiometric mixtures of CaCO3 , Al2O3 3H20, and Fe 0 at 1,375 ° C. The rates and extent of aluminum extractions were determined . The aluminum extractions from the aluminates were dependent on the presence of carbonate ions in the leach solutions , temperature , time , leach solution composition , and solid - liquid ratio of the slurry . The aluminum extracted from the calcium aluminates in water and in NaOH solutions varied from 4.6 to 22.9 percent . Virtually , complete extraction could generally be obtained for 12Ca0.7A120 and 4Ca0.A12 03 • Fe₂ 03 ; in one instance it was obtained for 3Ca0.A1203 , when an excess of carbonate ions was present over that required for the conversion of all of the calcium in the aluminates into CaCO3 . In some cases of poor aluminum recoveries , extractions could be improved by regrinding and releaching the solid residues .

Jan 1, 1964

By Noel N. Moebs

Coal mine roof failure is categorized according to character, trend, or pattern of occurrence. Two principal categories of failure are proposed--geology related and stress related. Geology-related failure includes both lithology and structure. Each of several subcategories reflects the probable cause of failure and thereby provides a basis for the selection of appropriate techniques for reducing the incidence of failure. These control techniques, depending on local conditions, may include supplementary support, destressing, reduction of mine air humidity, or a change in the customary support methods.

Jan 1, 1986

By Oliver Bowles

[In an endeavor to promote greater efficiency in the lime industry, the United States Bureau of Mines is preparing a series of preliminary reports dealing with particular problems of the industry. Through the circulation of these reports, it is hoped that sufficient interest may develop among lime-plant operators to prompt them to discuss with the bureau their our experiences with these problems. By such an interchange of ideas, it is believed that conclusion may be reached which will be of practical benefit to try entire industry. The first report, "Stripping problems it Limestone quarries of the Shenondoah Valley", Serial No. 2401, was issued during October, 1922. This report t is the second of the series. It is hoped that may operators will contribute additions to the information now at hand.]

Jan 1, 1922

By K. K. Kershner

This report describes an investigation by the Bureau of Mines designed to provide background data for extending and improving the applications of chlorine metallurgy in extracting metals from ores. Optimum conditions are given tor chloridizing galena, sphalerite, and chalcocite by contact with chlorine gas. Petrographic and chemical analyses of the sulfides used in the experiments are listed. Graphs are furnished showing the extent of chloridization of each metal sulfide over the temperature range of the observations. In each case, the first tests were made with the reaction chamber at room temperature. This temperature was increased by regular increments in succeeding tests until the temperature was reached at which quantitative conversion of the sulfide to chloride was observed. The data are also plotted for screen-size fractions of the sulfide minerals investigated. Data show that the extent of metal chloride formation was affected by chloridization time, particle size of the sample, and usually, the temperature of the reaction chamber. At 300° to 400° C. an anomaly was noted for both galena and sphalerite. The temperature at which this anomaly was observed varied according to the particle size of the mineral. Comparisons are made between the chloridizing characteristics of the mineral sulfides and their chemically prepared counterparts.

Jan 1, 1961

By W. W. Adams

"A gratifying decrease is noticeable in the number of men killed in the coal minas of the United States during the past six months as compared to the quantity of coal produced.During July last year, when 221 men lost their lives, the production of coal was over 50 million tons. In January, 1920, the production had increased to 56 million tons, or 11 per cent, while the fatalities, instead of increasing proportionately, actually decreased to 166, or nearly 15 per cent. Nor is this decrease a mere accident or coincidence peculiar to the month of January, as may be seen from the following table.From the figures shown above it may be observed that the average monthly production for January and the five months immediately preceding, was 49,500,000, or only 2 per cent below that for July, while the average number of men killed was 183, or a decrease of over 17 per cent."

Mar 1, 1920

By R. C. Hickman

Preliminary evidence indicated that the Chattanooga Shale might constitute a potential vast low-grade source of uranium. Investigation by core drilling indicated that while the Chattanooga Shale may constitute a resource for the future, the very low (0.006 percent) average uranium content is not economic when compared with the relatively higher grade western ores. A total of approximately 12,000 feet of test drilling was done in 72 drillholes, and large samples were mined for extractive and metallurgical testing. An experimental mine site was selected on the basis of the drilling project.

Jan 1, 1967

By Vladimir Adamek

This paper describes the Bureau of Mines development of a novel subsidence prediction methodology suitable to the mining and geologic conditions in the Northern Appalachian Coal Region. It describes the computation of vertical and horizontal movements, inclination, curvature, and horizontal strains. The substance of this method is the separation of the effects of lithology by introducing a correlation between hypothetically homogeneous overburden and existing lithologic conditions, while providing for different mining conditions, i.e., underground geometry and overburden thickness. The effects of lithology have been expressed in the form of a variable subsidence coefficient within the subsidence trough. The subsidence co-efficient is considered a constant for other predictive methods. Field data from 16 test sites at 11 Bureau longwall panel studies were used in the analysis. For each panel, the characteristics of the variability of the subsidence coefficient were defined. Regression analysis of the subsidence coefficients from all test sites on their locations relative to the edges of their respective panels yielded a third-degree polynomial equation. The results from additional longwall panel studies, not included in the regression analysis, were used to prove the validity of this method. To facilitate the use of this precalculatlon methodology, a computer program was written in BASIC for use on a personal computer.

Jan 1, 1987

By Charles L. Kimbell

While the statistical summary focuses on 1991 data, this update and outlook section draws on information available to the author as of the date of final preparation in early 1993. For all the press notoriety associated with the shift in the Near East crisis from the defensive posture of Desert Shield to the restoration of Kuwaiti sovereignty through Desert Storm, this was not the dominant event governing global economic thinking in 1991 and the first half and more of 1992. From the global perspective, the momentous political changes in the area that was the U.S.S.R. and in the smaller emerging transitional economy states of Eastern Europe will have even greater current and long-lasting effects on world mineral industry activities than the crisis in the Near East.

Jan 1, 1993

By Earl R. Maize

This is the first of a series of reports dealing with development of a method of strengthening bituminous-coal-mine roof. Later reports will describe the progress made with injecting high cohesive and adhesive bonding agents into bedding planes and mine tests of roof strata strengthened by the bonds formed. The concept of strengthening roof strata in coal mines by inserting steel rods in the form of bolts has been widely accepted by the coal industry. The benefits of increased production and safety derived from this type of roof support has more than justified the increased cost of roof bolting. However, not all coal-mine roof structure is amenable to this type of support, and failures occur owing to the heterogeneity and variable character of mine-roof strata.3/

Jan 1, 1957