Search Documents

To separate complex mineral mixtures according to their dielectric properties. Approach Develop a laboratory-scale continuous dielectric separator to separate mineral mixtures by exploiting their difference in dielectric properties. How it Works Dielectric separation is de-fined as the separation of particles based on their dielectric properties. The uniqueness of the Bureau's continuous separator, called the ?Rotating Drum Dielectric Separator,? is that it contains a high-voltage electrode con-figuration. The drum electrode consists of a series of coaxial parallel wires mounted on the outside surface of an Insulated cylinder. The screen electrode Is a wire mesh, quarter cylinder positioned outside and coaxially with the drum electrode. The drum electrode is placed in a liquid of dielectric constant K with the liquid level just above the drum's axis. The screen electrode is completely Immersed

Jan 1, 1981

By S. D. Maksimovic

The use of vertical surface degasification boreholes with bleeder systems and the use of a timbered bleeder system to degasify gob areas were studied by the Bureau of Mines. This report describes three gob degasification studies conducted in the Pittsburgh coalbed. One study was conducted to determine the number of panels degasified with one large borehole. The study showed that the borehole provided degasification for three panels. Another study was conducted during the retreat of a 35-acre panel with a single-entry and a two-entry bleeder system and a large surface borehole. A major portion of methane emitted from the panel was carried away by the bore-hole, leaving the bleeder entries relatively free of methane. The last study was made to determine the effectiveness of a timbered bleeder system. The bleeder entries successfully degasified the gob area when enough entries were available and adequate pressure was available to force the air through roof falls.

Jan 1, 1980

By J. E. Hamak

This publication contains analyses and related source data for 144 natural gas samples from 19 States. Of the total samples, 139 were collected during calendar year 1990. The remainder were collected earlier, but releases granting permission to publish were not received until 1990. All samples were obtained and analyzed as part of the U.S. Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free-market economies. This survey has been conducted since 1917. The analyses were made by mass spectrometer and chromatograph.

Jan 1, 1991

By Charlie Wyche

The principal minerals produced in the Dominion of Fiji in 1982 were unrefined gold, silver, and tellurium. The combined value of these commodities was about $16 million,2 representing over 85% of the total value of mineral output. Cement, sand and gravel, and quarry products were the other minerals produced in Fiji. Despite the small part played by minerals in Fiji's economy, exploration on land and in the coastal areas was carried out by several international mining companies representing Australian, British, Canadian, West German, and U.S. interests. At the end of 1982, 30 prospecting licenses covering 2,300 square kilometers were issued. Most licenses were for copper, zinc, gold, and silver. Total expenditure on mineral exploration was $3.5 million.

Jan 1, 1984

By R. R. Wells, W. W. Agey

"INTRODUCTION Oxide manganese ore from the Sheep Mountain property was of intermediate grade (23.0 percent manganese) and contained silica as the major impurity. The deposit from which the ore was taken is known as the Sheep Mountain manganese property and is 8 miles west of Durkee, Oreg. Test work was done in the metallurgical laboratories of the Bureau of Mines at Salt Lake City, Utah, on representative samples cut from a 290-pound shipment of crushed ore submitted by the Oregon State Department of Geology and Mineral Industries and reported to be typical of the Sheep Mountain deposit.ACKNOWLEDGMENTSThe authors wish to acknowledge the assistance of R. S. Doan, former assistant director of the Bureau of Mines, under whose supervision the manganese program was initiated in 1940, and, the valuable suggestions made to them by S. R. Zimmerley, now chief, Salt Lake City Division, Metallurgical Branch. Acknowledgment also is made to H. G. Poole and C. H. Schack for their suggestions and contributions to the organization and prosecution of the work of the Ore Dressing Section. Microscopic work on the ores and many ore-dressing products was done by L. G. Evans -and the late. B. E. Head. Our appreciation is extended also to H. E. Peterson, chief chemist, and members of the analytical staff for the many analyses made of the ores and ore-dressing products."

Nov 1, 1947

By F. W. Davis

For some years this subject has been of interest to metallurgists. Previous to the War some work was done in :Belgium. on the enrich.ntSnt of the blast with oxygen i.."'l. connection with the smelting of iron orei.; in the blast furnace. In the United States, the late .J. E. ,Joh."lson, .Jr., \ve.s :interested in the possible use of 0J1.:ygen for metallurgical operations ar.:i cerried on some experic:.ental work along these lines pre..,,-ious to his de.e.hft Dr. F. G. Cottrell, formerly Director of the :Bureau of Mines, De7?,H''(;:,-of,,:a:t: of the Interior, and now Direc'cor of the Fixed lifi trogen Itesearc:l-1 La -:c r;a.-o='Y, Depart­ment of .Agriculture, first directed. the Eurec:ru 1 s attention to this subject. When it first began this work, the Director of the Burea.t1. of Mines, beca11se of his interest in this investigatio:::i, asked :Mr. M. H. Roberts: Vice-President of the FraU:din Railway Supply Company to select an Advisory Corr:nittee to work with the BJ::eau on tl1is subject; it also asked Mx-. Robez·ts to act as Cha.irman of this C<)1.,_1l!lHtce. T!le personneJ. of the Comrnitee which was selected. by r. Roberts is as follows:

Jul 1, 1923

By G. P. Sturm

This work was undertaken by the Bureau of Mines in cooperation with the Environmental Protection Agency to determine photochemical specific reactivities of emissions from automobiles using leaded-premium-and regular-grade fuels and prototype lead-free fuels of comparable octane quality. Emissions were photoirradiated in a 100-ft3 environmental (smog) chamber constructed of aluminum and Pyrex glass at three sets of initial hydrocarbon (HC) and oxides of nitrogen (NOx) concentrations. Reactivity was measured and expressed in terms of rate-of-NO formation (RNo2) and dosages of oxidant, peroxyacetyl nitrate (PAN), peroiypropionyl nitrate (PPN), and formaldehyde (HCHO). The results indicate that the evaporative emission samples and the evaporative plus exhaust emissions samples from the lead-free fuels have, in general, higher reactivities per gram than those from the leaded fuels. For the samples containing only exhaust emissions, the only trend observed was the lower specific reactivity exhibited by the leaded premium fuel exhaust. These differences in specific reactivity are taken to reflect the differences in hydro-carbon composition of the fuels and their evaporative and exhaust emissions rather than any difference in lead content per se.

Jan 1, 1973

By B. Z. Zhong, T. Ong, W. E. Wallace, W. Z. Whong, Z. W. Gu, M. J. Keane

"Abstract-Diesel emission particles (DEP) from an engine operating on the Federal Test Procedure VDC were dispersed in an aqueous mixture of dipalmitoyl lecithin (DPL). a major component of pulmonary surfactant and saline and were tested for genotoxicity using the unscheduled DNA synthesis (UDS) assay with autoradiography techniques in cultured Chinese hamster lung cells. A DEP sample from the same source was dispersed in dimethyl sulphoxide (DMSO) and subjected to the same assay. Both dispersions (in DPL and DMSO) were found to induce UDS in a dose-related manner. After separation of the sample into supernatant and sediment fractions. the activity of the DEP sample was found to reside in the supernatant fraction for the DMSO-dispersed sample; and in the sedimentary fraction for the surfactant-dispersed sample. These findings further indicate that genotoxic activity associated with DEP inhaled into the lung may become bioavailable through the dispersion properties of pulmonary surfactant components.INTRODUCTIONTHE mutagenicity of diesel emission particles (DEP) has been studied intensively (LEWTAS and WILLIAMS, 1986). Carcinogenic effects of diesel exhaust in exposed animals have been reviewed (NIOSH, 1988) and an evaluation of carcinogenic risks to humans from diesel engine exhausts has been published (IARC, 1989). Using components of pulmonary surfactant such as dipalmitoyl lecithin (D PL), dipalmitoyl phosphatidylethanolamine (DPPE) or dipalmitoyl phosphatidic acid (DPPA) dispersed in physiological saline, we have previously shown that diesel soots express mutagenic activities in the Salmonella histidine reversion assay system and in the sister chromatid exchange assay using the cultured Chinese hamster lung (V79) cells. Mutagenic activity of diesel soots dispersed in DPL, DPPE and DPPA was quantitatively comparable to and in some cases greater than, the activity expressed by an equal mass of soot extracted by dichloromethane-dimethyl sulphoxide (DCM-DMSO) (WALLACE et al., 1989).Unscheduled DNA synthesis (UDS) is accepted and frequently included, as one of the tests in the battery of assays used to assess carcinogenic-mutagenic potential -of chemicals (MITCHELL et al., 1983). In this study, induction of UDS in V79 cells by DEP, dispersed in the major component of pulmonary surfactant DPL, was carried out. The purpose of this study is to validate the suggestion generated from our previous work that mutagens associated with inhaled particles may be dispersed or solubilized in the phospholipid component of pulmonary surfactant and become active in such a phase (WALLACE er al., 1989) and to test the fractionated DEP sample using UDS assay for a more complete evaluation of its genotoxicity."

Dec 1, 1995

By T. A. Lang

The objective was to develop a Program Plan of analytical studies and tests for determining (1) the optimum installation tension of a coal mine roof bolt, (2) the most valid bolt support theory or theories, and (3) the most valid roof failure theory or theories. On this basis a comprehensive literature search was made and significant material dealing with coal mine roof behavior, roof bolting and roof support was collected, reviewed, classified and analyzed. Emphasis was given to the influence of rock reinforcement on the control of deformation, stress field modification and mine roof stability. An assessment was made of the effect of various parameters including bolt tension, bolt pattern and time of installation, on the effectiveness of rock reinforcement systems, and equations developed for bolt tension as a function of these parameters, and rock properties. From these studies, a major program plan of tests and studies was developed for verifying and validating the most tenable theories of roof behavior and roof support and for determining optimum bolt installation tension.

Jan 1, 1979

By David C. Oyler, Paul B. Stubbs

The Bureau of Mines and United States Steel Corp. are conducting a joint project to monitor formation pressures at a large (23-well) coal- bed gas drainage field near Oak Grove, AL. Three monitor holes were drilled in late 1981, and pressure monitoring began in December 1981. The Bureau of Mines direct method was used to obtain gas content data from cores taken in the monitor holes. Comparison of the 1981 gas con- tent data from the monitor holes with initial gas content values obtain- ed from the production wells in 1977 indicates a 50-pct reduction in ad- sorbed gas content inside the pattern and a 29-pct reduction at one point 500 ft outside the pattern. The combination of pressure and gas content data has also allowed an in situ isotherm curve, relating the formation pressure to adsorbed gas content, to be developed for the area of the production wells. From the current rate of pressure decline (1 lbf/inz per month), the observed changes in gas content, and the isotherm curve, it appears that most of the early gas production came from within the pattern, but since 1981 (and possibly earlier) most of the gas produced has been migrating to the wells from outside the pattern area.

Jan 1, 1985

By J. B. Gayle

Numerous investigators have studied the addition of inert4 substances to coking blends. Generally, the results have yielded trends applicable only to the particular coals and inerts studied. Recently, somewhat more general results were obtained for cokes produced from blends containing added inerts, using the sole-heated oven. The present investigation represents an extension of this work to include a wider range of inerts and to determine the applicability of the various conclusions to cokes produced with the Tuscaloosa oven. The results indicated that an increase in dry-coal charge density of 1 pound per cubic foot (p.c.f.) caused a corresponding change in the hardness (1/4-inch tumbler index) of Tuscaloosa oven cokes of 0.9 percentage points. This value compares favorably with the value of 0.7 determined previously for the sole-heated oven and Bureau of Mines-American Gas Association (BM-AGA) retort.

Jan 1, 1961

By Russell R. Trengove

The Bureau of Mines developed by core drilling the Cove Meadow copper property, also known as the Patterson property, from May 6, 1949, to August 6, 1949. It is in the Cove Meadow mining district, northwestern Humboldt County, Nev., 102 miles northwest of Winnemucca. The purpose of the work was to determine possible reserves in a mineralized shear zone in andesite that has been partly explored by several surface cuts and two shallow underground workings. Production from this zone to August 1, 1,949, was 98 tons of hand-sorted copper ore assaying 5.1 percent. The development work performed by the Bureau of Mines comprised a study of the geology, mapping the area, sampling the outcrops, and exploring by diamond drilling the shear zone adjacent to the fault. Seven holes were drilled for a total of 1,246 feet. Mineral reserves indicated by the project are confined to a length of 500 feet along the strike.

Jan 1, 1950

By Philip C. Good

The Bureau of Mines investigated the feasibility of utilizing low-grade phosphatic shale as a feed for phosphoric acid production. Present practice in the phosphate mining operations of southeastern Idaho is to remove and either stockpile or waste low-grade phosphatic shales as the high-grade phosphate beds are selectively mined. Acid digestion studies were performed on uncalcined shale and on shale calcined to remove free carbon to determine phosphoric acid quality, yield, and amenability to filtration. The untreated shale, containing 21.4 pct P205, was digested with sulfuric acid in a single-tank reactor to yield phosporic acid and gypsum residue. Although 96 pct P205 recovery was attained in digesting uncalcined shale, only the calcined product gave satisfactory filtration rates. Calcined shale yielded phosphoric acid recovery of about 93 pct of the contained P205. It was higher in impurities than commercially prepared acid derived from high-grade western phosphate rock. An acid filtration rate of 745 lb P205/ft2/day was attained. This value is lower than the rate of 900 lb P205/ft that is generally considered to be acceptable in industrial production of phosphoric acid from high-grade phosphate rock.

Jan 1, 1981

By D. E. Shanks

As part of its effort to produce cell-grade alumina from clay, the Bureau of Mines investigated the hydrogen chloride gas-sparging crystallization of aluminum chloride hexahydrate (ACH) from aluminum chloride liquor, to provide information for optimizing the crystallization operation. Four parameters important in controlling the crystallization of the aluminum chloride hexahydrate and the concentration of impurities, particularly phosphorus and magnesium, in ACH crystals are (1) aluminum chloride concentration in the feed solution to crystallization, (2) hydrogen chloride gas flow rate, (3) temperature, and (4) concentration of phosphorus and magnesium also in the feed solution. Parameters 1, 2, and 3 affect crystal formation. The combined effects are very important because the phosphorus and magnesium concentrate in the crystals during the early stages of crystal growth. Aluminum chloride hexahydrate of cell-grade purity was crystallized from saturated aluminum chloride solutions containing less than 0.003 wt-pct P205 and 0.010 wt-pct MgO. Crystallization temperatures less than 600 C decreased crystal purity.

Jan 1, 1981

By R. M. Ray

The Bureau of Mines evaluated five commercial badge-type carbon monoxide dosimeters. Color changes in the badge reagent indicated the presence of carbon, monoxide. Possible effects of ambient conditions on dosimeter response to CO during or after coal mine fires or explosions were studied. Temperature and humidity changes did not change dosimeter sensitivity to CO. Contaminant gases such as CO2, N02, S02, and H2S had effects that varied with brands of dosimeters ranging from no effect to increased sensitivity to CO. Dosimeters tested after 6 months of storage showed an increase in failure rate as high as 25 percent. Tests were conducted to determine the effects on dosimeter time-for-color change caused by observer&apos;s sight (colorblind); lighting, and coal dust on dosimeters. No significant effects were observed. Observer variance was the most pronounced factor observed in all tests.

Jan 1, 1975

By Ronald D. Hill, Elmore C. Grim

1. Potential groundwater pollution resulting from large-scale surface mining in western states should be evaluated. 2. Criteria should be developed for the design, construction, operation, and abandonment of sediment ponds for maximum removal of suspended solids. 3. Methods should be developed for reducing suspended solids discharges from surface mines to less than 30 milligrams per liter. 4. A manual should be developed in the form of guidelines for sediment and erosion control planning and implementation. These guidelines must be designed to cover all phases of the coal surface mining operation (i.e., before, during and after mining). 5. A mine road manual should be developed for use by surface mine operators and State and Federal Agencies. Erosion, water control, and dust control should be covered in detail. 6. The block-cut, head-of-hollow fill, and mountain-top removal methods and techniques of contour mining should be evaluated, designed, and ultimately demonstrated in steep, mountainous terrain. Designs should be prepared for single and multiple seam applications. The demonstrations must show that these mining systems will secure rapid achievement of reclamation require¬ments and provide maximum, safe, economic coal recovery in an environmentally safe manner. 7. A Blasting Manual should be developed for use by industry and enforcement agencies. Stress should be placed on how to keep vibration levels and air blast pressures well below accepted safe criteria. Also, methods that can be used to control noise should be listed. 8. Investigations should be conducted on the effect of continued vibrations from blasting on structures that are near quarries. 9. Additional guidelines need to be developed for sampling and analysis of overburden material and associated coals for trace elements and noxious strata. Samples are extremely sensitive, and the source and manner of their collection, handling, storage, and treatment, as well as the techniques of analysis, need to be developed and described. This information can be used to predict possible future problems.

Jan 1, 1974

By E. L. Rawlins

A previous report4 has explained that pipe lines for the transmission of natural gas should be buried to minimize temperature fluctuations because when excessive the latter decrease accuracy in measuring gas volume and increase leakage of gas due to expansion and contraction in the pipe joints. These effects are governed by the rapidity of the temperature fluctuations and by the total variation over a period of time. The temperature of gas flowing through a pipe line depends to a large extent, upon the temperature of the ground adjacent to the pipe; hence, fluctuation of the ground temperatures at various depths determines the economic depth at which pipe lines should be buried. Scope and Purpose of Report This report covers a record of the daily atmospheric temperature fluctuations at Bartlesville, Okla., for 12 months and a-similar concurrent record of the temperature variation 1, 2, 3, and 4 feet below the surface of the ground.

Jan 1, 1928

By James A. Powell

The theory of electromagnetic fields indicates such fields could be used to detect and locate trapped miners. To be useful, the hardware of the system must meet a number of requirements, including small size, intrinsic safety, and rugged construction. Such hardware has been built, and the system has been tested by the Bureau of Mines and its contractors. These tests indicate that the electromagnetic method provides a practical means to locate miners in emergencies.

Jan 1, 1976

By G. S. Price

This paper, which describes the milling practice at the Page concentrator of the Federal Mining and Smelting Co., is one of a series being prepared by the Bureau of Mines. The Page mine and mill are located on Silver Creek, 3 miles west of Kellogg, Idaho, and 1 mile south of United States Highway No. 10. Supplies and concentrates are hauled by truck over an automobile road which connects Highway No. 10 with the property. The concentrator has capacity to treat 300 tons of ore per day and utilizes all-flotation methods of treatment. Power is supplied from the main line of the Washington Water Power Co. which runs from Spokane, Wash., to Kellogg, Idaho. Water is obtained from the mine and also from a well which is situated 1 mile distant from the concentrator and about 600 feet in elevation below the concentrator.

Jan 1, 1932

By Richard A. Winters

In 1987, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied the 6,022-acre Spring Basin Wilderness Study Area (OR-005-009) in order to evaluate its mineral resources. The study area is in Wheeler County about 13 miles southwest of Fossil, Oregon. No mineral resources were identified. The area is underlain by volcanic flows, domes and sediments ranging in composition from olivine basalt to rhyolite of the Clarno and John Day Formations. There are three mining claims in the study area, all apparently located for lapidary material. Samples of agate were of poor quality. Four of 13 alluvial samples, two inside and two adjacent to the area, contained gold; content ranged from 0.0000097 to 0.00416 troy ounce per cubic yard. About 23 percent of the Wilderness Study Area is covered by oil and gas lease applications.

Jan 1, 1988