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By Frank D. Lamb

Four samples of manganese-bearing material from the Aroostook County, Maine, deposits were tested at the Eastern Experiment Station of the Bureau of Mines at College Park, Md., to determine their amenability to beneficiation by ore-dressing methods. The samples represented material from the Maple Mountain-Hovey Mountain deposit, the Dudley farm, and the Burnham farm and contained 11 to 14 percent manganese. None of the tests produced appreciably enriched concentrates suitable for further treatment for the production of ferromanganese. The intimate association of the manganese minerals with iron and siliceous minerals requires extremely fine grinding to liberate the manganese minerals in these ores and prevents efficient concentration by physical means.

Jan 1, 1953

By R. C. Hickman

"INTRODUCTION The largest known deposits of ilmenite and rutile in Virginia are in Amherst and Nelson Counties. Other deposits occur in the State, but their extent is not known. One of the most promising of the latter is the deposit in Roanoke County on the T. M. Bush and the H. L. Hutchins property near Roanoke. A geophysical survey was made of the deposit, followed by core drilling. In April and May 1946, four holes were drilled, totaling 822 linear feet.ACKNOWLEDGMENTSIn 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, Oliver C. Ralston, chief, analyzes samples and performs beneficiation tests.The project was under the immediate supervision of Mitchell H. Kline, chief, Raleigh Division, Mining Branch,. Bureau of Mines."

Aug 1, 1947

By William G. Pariseau

Elastic-plastic finite-element simulation of cut-and-fill stoping in deep, narrow veins shows substantial quantitative agreement with field measurements of stope closure and fill pressure made at two mines in the Coeur d'Alene mining district of northern Idaho. The simulation procedure, validated by field data, was used in an analytical study of vein-wall closure and sill-pillar stress as influenced by fill modulus, rock modulus, and premining stress. Ratios of closure and pillar stress in the filled stopes to closure and pillar stress in the unfilled stopes are used as prediction indices for fill performance. In general, the support capability of fill increases dramatically as the ratio of fill modulus to rock modulus approaches 1. A significant reduction in closure .from the open stope--up to 75 percent--occurs with a relatively low-quality 10-ksi-modulus fill (rock modulus of 1,000 ksi). However, a higher quality fill is needed to achieve a substantial reduction in pillar stress from that of the open stope. A 100-ksi-modulus fill reduces pillar stress in both the 36-foot and l6-foot pillars (vein width is 10 feet) by about 50 percent relative to the open stope.

Jan 1, 1976

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 T. I. Weston

This is one of a series of papers being prepared for and published by the United States Bureau of Mines, describing mining and milling methods and costs at crushed-stone plants throughout the United States. These papers are designed to disseminate technical information regarding the methods used. The cost tabulations represent operating expenditures only and not total production costs. It is recognized' tat publication of total production costs might in many instances cause embarrassment to individual producers, as well as to the industry as a whole. However, operating costs are essential to the technical discussion and study of the methods employed. The attention of the reader is specifically called to this differentiation in order that no mis-understanding of the scope of the cost tabulations shall ensue. ACKNOWLEDGMENTS The author wishes to acknowledge the assistance-of F. W. Horton, mining engineer, United States Bureau of Mines, in the preparation of this paper.

Jan 1, 1933

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 B. R. Eichbaum

To develop technology to assure an ample supply of zinc and to reduce environmental pollution, the U.S. Bureau of Mines investigated alternatives to the roast-leach process for treating complex sulfide concentrates. Previous studies proved that low-grade zinc sulfide (ZnS) concentrates could be leached using chlorine-oxygen to produce zinc chloride (ZnCI2). The process involves high energy requirements for evaporating the pregnant solution to produce anhydrous ZnCl2 needed for electrolytic cell feed. An efficient hydrometallurgical process would facilitate treatment of lower grade ores than can be used in conventional processing and would render roasting unnecessary. An alternative method was devised for recovering ZnCl2 from solution. Zinc diammine chloride [Zn(NH3)2CI2] was precipitated from solution by adding ammonium chloride (NH4CI) and sparging with ammonia (NH3) to a pH of 6 to 7.5. The spent solution was treated with calcium hydroxide [Ca(OH)21 at 60° to 80° C for 1 to 4 h to remove remaining zinc and NH3. The Zn(NH3)2CI2 was heated to 300° to 400° C to remove NH3 and produce anhydrous ZnCI2. A possible flowsheet was devised and is included.

Jan 1, 1991

By Hsin Wei Wu

A real-time Diesel Particulate Matter (DPM) monitor has been developed on the basis of the successful National Institute of Occupational Health and Safety (NIOSH) designed Personal Dust Monitor (PDM) unit. The objectives of a recently completed Australian Coal Association Research Program (ACARP) study were to modify the PDM to measure the submicrometre fraction of the aerosol in a real-time monitoring underground instrument. Mine testing focused on use of the monitor in engineering evaluations to determine how conditions can be improved. Studies, including a selection during Longwall (LW) moves as described in this paper, demonstrated how DPM concentrations from vehicles fluctuate under varying ventilation and operational conditions. Correlation between the current SKC DPM measurement system and real-time DPM monitors were conducted and results from six mines show a correlation between elemental carbon (EC) and the new monitor DPM mass ranging from .51 to .81 with R2 >.90. These differences are suspected to be due to variations from mine to mine in aspects such as mine atmospheric contamination, vehicle fleet variations, fuel type, engine maintenance, engine combustion efficiency, engine behaviour or interference from other submicrometre aerosol. Real-time monitoring readily reflects the movement of individual diesel vehicles and allows pin-pointing of high exposure zones such as those encountered where various vehicles work in areas of constrained or difficult ventilation. DPM monitoring approaches that have been available for some time based on shift average monitoring do not readily allow successful engineering evaluation exercises to determine acceptability of pollution levels. Identification of high DPM concentration zones allows efficient modification of mine ventilation, operator positioning and other work practices t o reduce miners? exposures without waiting for laboratory analysis results.

Jan 1, 2010

By C. J. Thompson

Two sulfur compounds--the 2,2,5-trimethyl- and the 2,2,5,5-tetramethyl derivatives of thiacyclopentane--were identified in Wilmington, Calif., crude oil, using microdesulfurization and gas-liquid chromtography techniques.

Jan 1, 1963

By P. C. Good

Work was done to determine conditions necessary for efficient electrodeposition of aluminum from fused chloride electrolytes. Aluminum was deposited from a molten chloride salt electrolyte over a temperature range of 150° to 750° C. At lower temperatures in a heat-resistant glass cell, aluminum was deposited on stainless steel and on aluminum cathodes. The deposit was recovered in the form of light, feathery dendrites that could not be consolidated. At 750° C, molten aluminum was deposited at cathode current efficiencies as high as 90 to 100 percent on titanium diboride cathodes and in molten aluminum cathodes. Nitride-bonded silicon carbide was the best cell material, although porcelain was also used. The electrolyte consisted of a mixture of sodium and potassium chlorides in 1 to 1 mole ratio, containing aluminum chloride in concentrations ranging from 2 to 30 weight-percent in cells holding up to 1,000 grams of electrolyte. Generally favorable results were attained in studies made at temperatures greater than the melting point of aluminum.

Jan 1, 1966

By R. D. Leitch, J. G. Calverley

"INTRODUCTION Although many investigators have provided information on the strength and other properties of concrete the published literature cites few data on the effect of mixing cement with acid mine waters or on acid resistance of concrete in contact with mine waters. Most of the reported work on the effect of impure waters has dealt with the resistance of cement specimens to ""sulfate waters,"" that is, waters or soils with a relatively high sodium sulfate content. The ""Merriman test"" is used commonly to determine the corrosion resistance of cements for 28 days, but it does not seem certain that a cement having a high sulfate resistance in the Merriman or similar tests necessarily will show correspondingly great resistance to the sulfates of iron and, particularly, to sulfuric acid, which usually are present in acid mine waters. Extensive use of cement mortar for laying up masonry stoppings in coal and other mines and for constructing concrete mine haulageways and shaft linings, coal-storage and other retaining walls, highway bridges, culverts, and many other types of construction where it is difficult to obtain fresh water for mixing or where the structures are later exposed to contact with acid waters makes it important to know the effect of these conditions on cement and whether there is a cement better suited for such work than ordinary portland cement.CONDUCT OF THE INVESTIGATIONFor a short time early in 1935 the opportunity to obtain at least some additional information on the effect of acid mine water on cements was presented by the Relief Works Division, which provided money for irregular and indefinite employment for several months. Purchase of apparatus or material was not permitted under this arrangement, and indefinite duration of the work, intermittent employment, and finally complete cessation of the work prevented planning for extensive investigation of this particular problem."

Jan 1, 1940

By F. E. Brantley, D. M. Yergensen, D. A. Martin

Fluidized - bed roasting was investigated as a means of decomposing gypsum and gypsum mixtures to produce a gas rich in sulfur dioxide and a lime or portland cement residue . Ninety- eight percent desulfurization of gypsum in a 10 - inch fluidized- bed reactor took 1.5 hours at an operating temperature between 1,200 ° and 1,225 ° C. A cement- type residue was obtained but had to be refired at 1,450 ° C before mortar prepared from it met the physical specifications for cement .

Jan 1, 1963

By R. L. Soderberg

Large open stopes mined by vertical crater retreat or sublevel s are sometimes backfilled with uncemented sand to support the stope walls and alleviate rock bursts. The failure of bulkheads in two different mines prompted a research project at the Bureau of Mines to prevent a recurrence of these failures. A series of laboratory tests with drains and sand filters was conducted to measure the bulk-head pressures when adequate drainage was maintained. Results showed that bulkhead pressure was reduced to near zero while drains were in operation, as compared to full hydrostatic pressure when drains were blocked or drainage was restricted. A relatively simple, free-draining bulkhead was shown to be adequate.

Jan 1, 1985

By L. B. Berger

Each winter brings its toll of deaths and serious accidents from the deadly gas, carbon monoxide. Newspapers carry warnings to the public of the dangers of this gas, and frequent now items retort the finding of persons dead or unconscious from the effects of carbon monoxide, yet these accidents continue. Either those warnings are not read, or they are unheeded by people who feel that "It can't happen to me." It can happen to you - carbon monoxide is no respecter of persons, as evidenced by items appearing daily in newspapers all over the country. Carbon monoxide has been a threat to human safety as long as man has used fire to keep himself warm and to cook his food. The burning of any fuel that contains carbon may produce carbon monoxide. This is true of solid fuels such as coal, coke, and wood; of liquid fuels such as oil, gasoline, and kerosene, and of gaseous fuels such as natural or manufactured gas. In the process of combustion the carbon in the fuel unites the chemically with tat oxygen of the air to form carbon dioxide (CO2), however, if the supply of air is not adequate, combustion is incomplete and carbon monoxide (CO) will be formed.

Jan 1, 1943

By Donald O. Rausch, Robert H. Merrill, David W. Wisecarver, S. Jackson Hubbard

Results are reported for stress - relief borehole - deformation measurements made in three underground openings near open - pit mines in the Ruth mining district , Nevada . A total of 134 deformation measurements were made in 8 boreholes . These measurements determined the regional stresses in the horizons above , below, and at the elevation of nearby open - pit mine floors ; knowledge of these stress conditions is considered essential information relative to certain aspects in the designing of stable pit slopes . The determinations indicate that the stresses in the district are due to the gravitational load of the overburden in a confined stress field .

Jan 1, 1964

By K. K. Kershner, J. G. Donaldson

This investigation was conducted to obtain data on optimum conditions for chloridizing metal sulfides . Salt- roasting galena at 450° C for 8 hours chloridized 75 percent of the lead ; in an equal time of treatment at 750° C , the process chloridized 42 percent of the zinc in sphalerite . Hydrogen chloride at 500° C completely chloridized galena in 15 minutes , and at 600° C converted all of the zinc in sphalerite to the chloride in 4 hours .

Jan 1, 1963

By P. E. Churchward

Rhenium sources and recovery methods were investigated by the Bureau of Mines to delineate potential resources of the metal. The only significant rhenium resource appears to be about 28,000 lb of rhenium contained in the domestic annual output of approximately 20,000 tons of byproduct molybdenite concentrates from porphyry copper operations. An estimated 70 to 80 pct of this rhenium is potentially recoverable by processing the rhenium-bearing fumes and dusts obtained during conventional roasting of molybdenite concentrate. At 70 pct recovery this would amount to 19,600 lb of rhenium. A more conservative estimate by the Committee on Refractory Metals of the National Research Council (1513 is that 12,000 lb of rhenium metal could be produced annually from current production of molybdenite from porphyry copper operations in the United States. A procedure was developed in the laboratory for recovering rhenium in the form of electrolytic flake by electrowinning the metal from a solvent extraction strip solution. The procedure included (1) water leaching of molybdenite roaster flue dust, (2) selective extraction of rhenium from the leach liquor by contacting it with a kerosine solution of a quaternary amine, (3) stripping of rhenium from the loaded organic solution by a perchloric acid solution, and (4) electrodeposition of rhenium from the loaded strip liquor. Raw material for the studies was flue dust containing 0.48 pct Re, 35 pct Mo, and 23 pct S in sulfide and sulfate form, and small amounts of numerous metallic impurities. Water leaching dissolved 85 pct of the Re and yielded a solution that was 13 in sulfuric acid and contained, 1 g/l Re and 16 g/l Mo. The solvent extraction strip solution that was electrolyzed for rhenium deposition was 1 molar in perchloric acid and 1 molar in ammonium sulfate and contained 13 g/l Re and 0.01 g/l Mo.

Jan 1, 1963

By R. Blickensderfer

Several thin film absorber stacks with spectrally selective characteristics were developed by the Bureau of Mines. The stacks consisted of a silicon thick film or a zirconium compound thin film on a reflective thin film of silver. The zirconium absorber films, with the general formula ZrCxOyNz, were prepared by reactively sputtering zirconium or zirconium carbide in argon with small amounts of oxygen, nitrogen, or both, or by oxidizing zirconium films in air. A few similar types of films were prepared from titanium. The short-wave absorptance over the solar spectrum, a(s), and thermal emittance at 600 K, e(600 K), of the solar absorber stacks were calculated from room-temperature reflectance data. The values of a(s) ranged from 0.47 to 0.93, e(600 K) from 0.49 to 0.034, and the ratio a(s)/e(600 K) from 1.7 to 34. The specimen with the best combination of properties, a ZrNx-Ag stack, had a solar absorptance a(s) of 0.85 and a ratio, a(s)/e(600 K), of 24. The effect of film thickness and composition on spectral selectivity was determined. An emissometer for measuring normal total emittance up to 800 K and a method for determining a (s), e(T) (hemispherical), and a(s)/e(T) using simulated solar radiation are described. A calorimetric method for measuring a(s) and e(T) (hemispherical) at elevated temperature is also described. Measurements made on several specimens agreed favorably with calculated values.

Jan 1, 1976

By Paul M. Tyler

The value of mica depends chiefly upon the size of the flat sheets into which it can be split and also upon whether it is clear or stained. Muscovite (white mica) and philogopite (amber mica) are the micas of commerce. Biotite (black mica) and other varieties are virtually unsalable. Vermiculite, an altered mica having the extraordinary property of expanding greatly when heated, preferably should not be classed commercially as mica. Mica is marketed as (1) cut or uncut block, (2) sheet, (3) splittings, and (4) wet or dry ground mica. In the United States, mica that will not yield flat films over about 1-1/2 inches square, or that is ruled, rumpled, or flawed in any way, can be sold only as scrap, its sole use being for making ground mica. Only sizes that will yield rectangles 1-1/2 by 2 inches or larger can be classed as sheet quality; slightly smaller sizes may be classed as punch, and under certain circumstances still smaller sizes, down to about 1 inch square, may be used for splittings, which are mostly a thousandth of an inch thick or even thinner. Splittings, however, are produced in large quantities only in British India, where labor costs very little. Even there the work is done mostly by children, who not only work cheaper but have a delicacy of touch that enables them to do the splitting faster and better. No mechanical process yet devised will permit ordinary splittings to be made economically in the United States.

Jan 1, 1938

By L. D. Schmidt

Now that the war is over, there is a great revival in popular demand to decrease pollution of the atmosphere in our cities. Great cities, such as Pittsburgh, are starting to enforce laws against violators of smoke ordinances. The substitution of low-temperature coke for bituminous coal in household heating is a most promising field for helping to eliminate the smoke nuisance. This Information Circular is written to assist in the very worth-while effort to reduce atmospheric pollution. Herein are de- scribed recent German developments in the production of low-temperature coke. Operating and cost data are given on German commercial-scale low- temperature carbonization plants.

Feb 1, 1947