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By F. P. Haver

Because of increasing concern with air pollution, the Bureau of Mines has developed a hydrometallurgical procedure to obtain elemental sulfur from chalcopyrite (CuFeS2) by means of the following reaction: CuFeS2 + 3FeCl3 ? CuCl + 4FeCl2 + 2S. Under optimum conditions, 99.6 percent of the copper and 71.6 percent of the iron were extracted in 2 hours from a typical mill concentrate containing 75 percent CuFeS2 and 15 percent pyrite (FeS2). At the same time, 68.2 percent of the sulfur in the concentrate was oxidized to the elemental form. The leach was highly selective; gangue minerals, including pyrite, were not attacked, thus accounting for the relatively low recoveries of iron and sulfur. To obtain these results, the concentrate was ground to 98.9 percent minus 325 mesh, and 300 grams was treated with 1 liter of boiling ferric chloride (FeCl3) solution. The FeC13/CuFeS2 ratio was 2.7. Cement copper containing 99.9 percent copper was recovered from the leach solution by cementation on sponge iron. Excess iron, dissolved during leaching and cementation, was removed from the stripped solution by crystallization. Ferrous chloride (FeCl2?4H2O), obtained as a byproduct, was converted to high-purity ferric oxide (Fe203) and HCI by an oxidizing roast. The hydrochloric acid was then electrolyzed to obtain chlorine, which was used to regenerate the leach solution. The leach residue, which contained ~50 weight-percent elemental sulfur, was treated with an organic solvent to recover the sulfur and cyanided to reclaim gold and silver.

Jan 1, 1971

By Oliver Bowles

Limestone, including dolomite, is the most widely used of all rocks - nearly 300 million tons annually in the United States alone. It occurs in some form in every State and is produced in thousands of localities. Because of its attractiveness, substantiality, and durability it is employed extensively as a building stone. In crushed and broken form it is used for concrete aggregate and railroad ballast and in highway construction, metallurgy, agriculture, and a host of chemical and industrial processes. This paper proposes to furnish general information on the origin and occurrence of limestone and dolomite, chief production centers, major uses, and methods of quarrying and preparing stone for market. Footnote references will guide the reader to sources of more complete information.

Jan 1, 1956

By Aleksandar D. Bugarski

Three types of uncatalyzed diesel particulate filter (DPF) systems, three types of high-temperature disposable filter elements (DFEs), and one diesel oxidation catalytic converter (DOC) were evaluated in underground mine conditions for their effects on the concentrations and size distributions of diesel aerosols. Those effects were compared with the effects of a standard muffler. The experimental work was conducted directly in an underground environment using a unique diesel laboratory developed in an underground experimental mine. The DPF systems reduced total mass of aerosols in the mine air approximately 10-fold for light-load and 20-fold or more for high-load test conditions. The DFEs offered similar reductions in aerosol mass concentrations. The efficiency of the new DFEs significantly increased with accumulation of operating time and buildup of diesel particulate matter in the porous structure of the filter elements. A single laundering process did not exhibit substantial effects on performance of the filter element. The effectiveness of DPFs and DFEs in removing aerosols by number was strongly influenced by engine operating mode. The concentrations of nucleation mode aerosols in the mine air were found to be substantially higher for both DPFs and DFEs when the engine was operated at high-load modes than at low-load modes. The effects of the DOC on mass and number concentrations of aerosols in mine air were relatively minor when compared to those of the DPF and DFE systems.

Jan 1, 2009

By Walter Kawa

The hydrogenation of phenyl ether, benzyl ether, and phenyl sulfide in the presence of iron catalysts was studied by the Bureau of Mines to gain a better understanding of the role of iron catalysts in the hydrogenation of coal. The carbon-oxygen and carbon-sulfur bonds in these compounds may be similar to some of the carbon-oxygen and carbon-sulfur bonds in coal which react during the early stages of liquefaction by hydrogenation. Experiments were made in batch autoclaves for 4 hours; hydrogen was at a pressure of about 540 atmospheres. In the hydrogenation of phenyl ether at 400° C, metallic iron catalyzed both hydrogenolysis (splitting-hydrogenation) and nuclear hydrogenation (addition of hydrogen to aromatic rings) reactions, Products were principally benzene and cyclohexane. The activity of metallic iron was decreased by adding carbon monoxide or a reactive sulfur-containing organic compound. Ferrous sulfide catalyzed the conversion of phenyl ether to benzene, phenol, and small amounts of cyclohexane. Hydrogenolysis of benzyl ether was catalyzed by metallic iron and to a lesser extent, by ferrous sulfide at 250° C. No nuclear hydrogenation was observed with either catalyst. Conversion of phenyl sulfide to benzene was nearly quantitative in experiments made at 250° C with equimolar quantities of phenyl sulfide and metallic iron or iron as ferric oxide. Conversions of metallic iron and ferric oxide to ferrous sulfide were nearly stoichiometric. No reaction of phenyl sulfide occurred in the presence of ferric oxide and water, and very little occurred in the presence of metallic iron and water. Ferrous sulfide also catalyzed the hydrogenolysis of phenyl sulfide to benzene, but conversion was lower than in experiments with metallic iron or ferric oxide. The activity of ferrous sulfide was increased by adding water and decreased by adding hydrogen sulfide. The results of this study suggest that ferrous sulfide is an active form of iron when iron is used as a catalyst for the hydrogenation of coal.

Jan 1, 1963

By C. B. Kenahan

A summary of Bureau of Mines research on recycling, reuse, and disposal of mineral-, metal-, and energy-based wastes is presented, accompanied by an extensive bibliography of related publications. The Bureau's waste recycling and disposal program is directed toward the following four main areas of research and development: (1) extraction of mineral, metal, and energy values from urban refuse; (2) upgrading and recycling of automotive and related ferrous and nonferrous scrap; (3) recovery, utilization, and stabilization of mine and mill processing wastes, and (4) recovery and reuse of values from industrial waste products. This publication updates Bureau of Mines Information Circular 8529, which was issued August 1971.

Jan 1, 1973

By M. Clair Smith

The Sweetwater, Castro, Trinidad, New London, and Hilltop chromite properties are situated within an area 8 miles long and 1 mile wide between San Luis Obispo city and Morro Creek, San Luis Obiso County, Calif. Development work at this group of mines was a part of a long-range project by the Bureau of Mines to develop strategic mineral reserves in the United States in accordance with the Strategic Minerals Act of 1939. The junior author of this report participated in the preliminary examinations made in 1941 of the chromite deposits that later in the same year were the subject of more intensive investigation under the immediate supervision of the senior author. The ore occurs in lenses and kidneys in masses of dunite contained in large poridetite areas. Production has boon in the form of lump ore and concentrates from disseminated ore. Work by the Bureau of Miner included surveying, mapping, trenching, sampling, and assaying. It is summarized separately in the text under the name of each mine investigated. The report gives a brief history of the district, describer the concentrating plant of the Castro Associates, and gives detailed results on sampling and assays at the various proportion.

Jan 1, 1951

By W. W. Simpson

The Bureau of Mines conducted research to determine the effects of potassium trithiocarbonate (KTTC), a degradation product of potassium ethylxanthate (KEX), on flotation of chalcopyrite and molybdenite. Small amounts of KTTC were identified in fresh and aged solutions of KEX using thin-layer chromotography. Hallimond tube flotation tests on pure minerals showed that KTTC acts as a weak collector for chalcopyrite. Both KEX and KTTC tend to depress molybdenite, but the depression effect is easily overcome by addition of a small quantity of fuel oil. The results of the Hallimond tube tests were confirmed in batch flotation tests using a porphyry copper ore.

Jan 1, 1983

By J. Vance Batty

Two methods were devised and evaluated for quantitatively measuring the amount of oleic acid on flotation products and in flotation waters. One method involved use of an organic solvent to remove carbon-l4-tagged oleic acid from mineral surfaces and flotation water phases with subsequent radio-metric analysis of the extracts. Studies showed this method to be slow and subject to large variations in accuracy and reproducibility. In the second procedure, tagged oleic acid was measured directly on the surfaces of dried mineral products. Oleic acid in the water phase was determined by adsorbing it on fine mineral, drying, and radiometric counting. Quantitative analysis of oleic acid on flotation products from bench-scale flotation tests with synthetic mixtures of ore minerals and quartz and with natural ores showed this method to be fast, accurate, and reproducible.

Jan 1, 1968

By Ernest A. Curth

The Bureau of Mines studied pressure changes in coal pillars by using encapsulated hydraulic pressure cells to measure relative changes in stress developed during mining. The data indicate that (1) abutment stresses were detected when the pillar line is within 42 to 100 feet, (2) vertical pressure increases as coal is mined in the pillars, (3) at first pressure is higher at the edge of the pillar than in the core, but as mining progresses, the higher pressure is measured in the core of the stump, and (4) in the two instances where lateral pressures were measured, they remained lower than the vertical pressures during pillar extraction. The data also indicate that the mean vertical pressure increase, 6P, in a pillar is roughly related to the percent of pillar extracted, A, by the empirical parabolic equation

Jan 1, 1967

By Erie C. Donaldson

Gas-displacement tests were made in Berea Sandstone and Arbuckle Lime-stone cores to determine the relative permeabilities to gas, oil, and water for two-and three-phase dynamic systems. Three-phase relative permeabilities were obtained by displacing oil and water from the core with gas and measuring the flow rates of the three fluids simultaneously. It was found that relative permeabilities to fluids in a porous medium are affected by the saturation distributions of other fluids in the medium as well as by their own saturation distributions.

Jan 1, 1966

By R. W. Stahl

Coal mining has been revolutionized by the continuous miner. This machine has replaced, or has combined into 1, 3 former operations: Cutting, blasting, and loading. During the 25-year period before this machine was introduced, advances had been made in transportation, but the actual "coal getting" remained virtually the same. As frequently occurs, the multiple-purpose continuous miner introduced a new hazard--more rapid liberation of methane. The coal output formerly obtained from 10 to 20 working places might now be obtained from 1. It is true that circulation of air was generally increased; but the bulk of this machine virtually precludes continuous flow of air across the face, where gas may accumulate. Apprehension about this possible hazard led the Bureau of Mines to test face atmospheres during operation; and Report of Investigations 5288, Methane Buildup During Cutting and Continuous Mining Operations (published in 1956), presents proof that real danger may be present in many otherwise well ventilated mines.

Jan 1, 1958

By V. M. Benson

A simplified, routine method for determining lithium in lithium-bearing rock is presented. The sample is decomposed by repeated treatments with nitric, hydrofluoric, and perchloric acids. Since this procedure does not appreciably dissolve beryl, interference by beryllium (the principal interfering cation) is minimized for most samples. The salts are brought into solution with water and enough citric acid-ammonium citrate buffer is added to make the final volumetric dilution 0.20 M with respect to citrate. The addition of citrate greatly reduces anion interference in the hydrogen-oxygen flame, slightly increases the intensity of the lithium 671 millimicron emission line, and reduces the effect of most of the interfering cations to the extent that analytical separations are not necessary. The accuracy of results of single determinations of lithium in a pegmatite containing spodumene, lithium-bearing mica, and beryl are approximately equal to that obtained by other flame methods, INTRODUCTION This investigation was undertaken in Bureau of Mines laboratories to develop a reliable, rapid, routine analytical method for determining lithium in lithium-bearing minerals. The requirements of the procedure were that the method should be applicable to the analysis of a variety of lithium-bearing ores and test products, and the results would be reasonably accurate for materials containing 0.05 to 8 percent Li20.

Jan 1, 1961

By J. S. Hansen

In support of its objective to conserve mineral resources by minimizing premature failure of materials, the Bureau of Mines conducted a cooperative study with the U.S. Department of Energy on the erosion and abrasion resistance of hard materials for valves in coal conversion systems. This report describes a newly developed erosion-testing apparatus and presents data on the erosion resistance of over 200 materials. Erosion resistance of most metals was comparatively low. In contrast, ceramics and cermets such as B4C, WC, SiC, Si3N4, and TiB2, when fabricated to minimize porosity, displayed greater than five times the erosion resistance of metals. Coatings such as boron diffused into Mo and WC, chemical-vapor-deposited TiCN, and electrodeposited TiB2 were highly erosion resistant if applied in thicknesses ranging from 60 to 75 µm. Erosion resistance of cemented carbides was inversely related to metal binder content.

Jan 1, 1979

By James C. Barker

Yttrium and rare-earth element. pegmatite dikes are associated with a peralkaline granitic and nephelene syenite complex near Dora Bay on southern Prince of Wales Island. Mineralized dikes were mapped and sampled during USBM investigations in 1987 and 1988. Coarse-grained pegmatite dikes, which emanated as late-stage magmatic fluids from the intrusion, further evolved into vein-dikes and ultimately silica-rich veins. The dikes can be traced up to two miles along a north-south zone. Lithophile elements exhibit a pronounced zonation in vein-dikes and veins that are distal to the Dora Bay complex with increasing values correlating with increasing distance from the complex. The pattern of mineralization suggests very late stage magmatic fluids containing the incompatable lithophile elements were injected into a preexisting north-south fracture zone. REE mineralogy exhibit fine-grained intergrowths of principally thalenite and bastnaesite with lessor monazite and eudialyte. Euxenite contains most of the columbium values and zircon is commonly associated with the dikes. Estimates of inferred and hypothetical resource tonnage range from 1.7 X 1C6 to 8.5 X 106 st for two deposits. Contained RED (including yttrium) averages 0.5 pct and ranges up to 2.0 pct. Deposits are of polymineralic composition and about half of this resource comprises the heavy yttrium subgroup.

Jan 1, 2011

By John A. Organiscak

[Fugitive Just is generated alone unpaved mire reads from intermittent equipment traffic. Typically, the majority of such traffic consists of trucks hauling either mine product or waste [rum the surface mime pit and/or the processing plant. Fugitive dust generated along these unpaved mine roads includes particles of all sizes which become airborne. The potential hazards include the deleterious effects to human health of inhaled dust, traffic visibility hazards and environmental impacts on the localized area by the larger-sized visible airborne dust. Two held surveys were recently conducted to quantify fugitive dust generation and dispersion from truck traffic on unpaved and untreated mine haulage roads For these surveys., airborne glow sampling was conducted at multiple sampling fixations away from an unpaved haulage road at a limestone quarry/plant and at a coal mine preparation plant lo measure the size characteristics, concentrations. and dispersive behavior of the dust cloud generated from truck traffic- Results show that at least 80% of the airborne Just generated by haul trucks was larger than 10 µm- Airborne respirable, thoracic, and total dust concentrations all decreased and approached background concentrations 30.5 in (100 feet) from the road This report describes the average and instantaneous peak dust levels that were measured tip to 30.5m (100 feet) Iron the haulage road. Keywords: Unpaved mine road, fugitive dust, silica.]

Jan 1, 2008

Argentina follows Venezuela and Mexico as the largest producers of crude petroleum and natural gas in Latin America. Argentina 1S practically self-sufficient in fuels, but relies substantially on imports for its supply of copper, iron ore, ferroalloys, sulfur, and fertilizers. Mining activity is limited and is in an incipient stage of growth, considering the country's potential for mining. Most nonfuel mineral output in 1979 consisted primarily of minerals used for construction, while only 9% are other nonmetallic, and 2% are metallic minerals. Argentina is Latin America's major producer of boron minerals and uranium (yellow cake). Mineral exports consist primarily of borates, uranium concentrates, and of late, some tin. These exports have in the past been shipped mostly to Great Britain. London banks have been involved in arranging financing for St. Joe Minerals Corp. IS planned development of the El Pachon copper deposit (see map), and were being counted upon to also back the development of large copper and manganese projects. The following is a review of Argentine mineral production in 1979: (For 1981, the production of boron minerals is put at 167,000 metric tons and uranium at 300,000 metric tons.)

Jan 1, 1982

By Walter E. Lewis

A mothod of cutting St. Poter sandstono by streams of water under pressuro from nozzles and pumping the resulting, sand to the surface has roduced the cost of storm-sowor construction in the Minneapolis-St. Paul aroa. The hydraulic tunneling method, has boon in uso since 1934, and it is adaptable only to the lower part of tho St. Potor, sandstone, which lios within or just abovo the ground-wator levol. Tho upper part of the formation, immediately bolow tho Plattoville limestone, 18 comonted and camot bo mined by hydraulic mothods. The tunnel oporation observed in this instance is a main storm sowor starting at tho Mississippi Rivor below the 10th Avenuo SE bridge and will be drivon 6,000 foot at a grado of 1 foot por thousand undor the city of Minneapolis to Konnody and Arthur Stroots NE. A lateral storm sowor, which branchos from the main sovor at 8th Street SE, will oxtond from 10th Avonuo SE to 15th Avonuc SE. Tho tunnele are being drivon with the floor approximately at ground-wator lovol. All waters ontoring the main storm sower vill drain into the Mississippi Rivor. Tho main storm sewer cross soction is excavated to a roughly hox- agonal shapo 10 foot high by 10 foot wido at the contor. The upper half of the tunnol soction is solidly lined with either timber or stool. After all oxcavation is completed, the tunnel will be finished with a concrete circular lining 8 feet in inside diameter. The lateral storm sewer is excavated to a 5-1/2-foot by 7-1/2-foot section and will event- ually be finished with concrete to a modified horseshoe-shaped section 6 feet by 4 feet. Where the back or walls are considered unsafe during excavation, the upper half of the tunnel is lined solidly with timber. The equipment used by the Sower Division, City of Minneapolis, has been selected to meet a number of applications in storm-sewer work with diversified usage in mind. The sand pumps used on this job are rubber-lined, designed to work against a head of 100 foet. Either 4-inch or 6-inch diameter suction and discharge openings may be used. Other equipment, such as pipe, mine rail, flexible hoses, compressors, and general surface shop equipment, is drawn from a contral warohouse. It may be either new or used, depending on what is available at the warehouse. Much of the pipe and mine rail has been used for many years on several different tunnol jobs.

Jul 1, 1950

By Noel N. Moebs

Five LANDSAT lineaments in the coal mining region of southwestern Pennsylvania were investigated by the Bureau of Mines to determine their geologic character, relation to subsurface conditions, and the means of discriminating one from another. The investigation included earth resistivity and very low frequency (VLF) electromagnetic traverses, soil moisture sampling, and a correlation with coal mine roof conditions. The lineaments could not be detected by the methods used, suggesting that they might be a surface phenomenon unrelated to subsurface geologic structures or roof stability in coal mine workings beneath.

Jan 1, 1987

By Frank A. Peters

An evaluation is made of a lime-soda sinter process for extracting alumina from clay. In this process, alumina is extracted by sintering clay with soda ash and limestone and then leaching the sinter with a dilute sodium carbonate solution. The sodium aluminate solution formed during leaching is separated from the residue and treated with lime in autoclaves to remove dissolved silica before alumina trihydrate is precipitated with carbon dioxide. The tri-hydrate is then calcined to a-alumina. Two options, dry grinding and wet grinding, are used in the sintering step. The fixed capital costs for plants producing 1,000 tons of alumina per day are $72 million for the dry grinding option and $66 million for the wet grinding option on a Marshall and Stevens chemical equipment index basis of 240.0. Specific geographic locations of plant and raw material sources are not assigned, but, since this process requires large quantities of both lime-stone and clay, the plant site is considered as variable with relation to the clay mine and limestone quarry. A nomograph is given to find operating costs at various delivered costs of clay and limestone. If the plant is located nearer the limestone quarry so that the delivered cost of clay is $2 per ton and the delivered cost of limestone is $1 per ton, the operating costs are $76.47 and $71.61 per ton of alumina for the dry grinding and wet grinding options, respectively. On the other hand, if the plant is located nearer the clay mine so that the delivered cost of clay is $1 per ton and the delivered cost of limestone is $2 per ton, the operating costs are $80.15 for dry grinding and $75.34 for wet grinding.

Jan 1, 1967

By John Ward Smith, Neil B. Young

Shale specific - gravity to oil - yield relationships were developed for black shales of the New Albany Formation of Kentucky from data collected on core samples representing the complete section of the formation in three counties . Linear equations for estimating oil yield from measured specific gravity and for estimating specific gravity from measured oil yield were shown to be applicable within small error limits to all the sites tested . Variation in pyrite content is the largest source of error .

Jan 1, 1964