Search Documents

By John J. S. Sebastian

A laboratory-scale investigation was made of the basic problems involved in developing a ceramic heat exchanger to operate at high temperatures for using nuclear heat from gas-cooled process-heat reactors. Technical data were obtained on transferring heat by forced-convection from helium to air in a single-tube vitreous-alumina heat exchanger. Coolant air was passed through the annulus parallel with, and either concurrently or counter to, the flow of helium inside the tube. The data obtained pertain to removing heat from the helium. Average inside film coefficients were determined at mean surface temperatures of 200° to 1,570° F., inlet-gas temperatures of 1,450° to 2,665° F., and Reynolds numbers up to 560. The gas-to-surface temperature ratios were varied from 1.05 to 7.6. The tabulated results are shown in the appendix at the end of this report. The film coefficients of heat transfer were correlated by taking into account the physical properties of the helium at the average fluid temperature. With experimental conditions pointing to a laminar flow, the Nusselt number was found to decrease as the ratio of gas-to-wall temperature was increased to a value of 3. However, within the range tested, gas-to-wall temperature ratios above 3 did not affect the Nusselt number, regardless of the value of the Graetz number. Thus, beyond this point any increase in this ratio ceased to influence the heat-transfer relationship.

Jan 1, 1962

By Frank A. Peters

With the current renewed interest in advancing the technology for producing alumina from domestic raw materials, revisions of previous cost estimates to provide planning data are urgently needed. Completely new cost estimates on a 1973 basis are included for four alumina-from-clay processes and one alumina-from-anorthosite process. These estimates are based on new or previously calculated material balances, recalculated heat requirements, and new equipment designs. The use of larger and more modern equipment has permitted a significant reduction in labor requirements as well as equipment costs. Chemical prices, labor rates, and utility rates typical of late 1973 are used in these cost estimates. In addition to the revised cost estimates, all 21 previously published alumina evaluations compiled by the Bureau of Mines were updated to show the effect of inflation using an inflation index and late 1973 chemical prices, labor rates, and utility rates.

Jan 1, 1974

Legislation and Government Programs.-On February 4, 1977, the Occupational Safety and Health Administration (OSHA) issued its final environmental impact statement on the occupational use of inorganic arsenic.2 The statement examined the ramifications of the original proposed standard published in the Draft Environmental Impact Statement (DEIS).3 The DEIS proposed to limit the exposure of employees to no more than 4 micrograms of arsenic per cubic meter of air as determined on an 8-hour-time-weighted average basis; or a ceiling limit of 10 micrograms of arsenic per cubic meter of air based on a 15 minute sampling period. The purpose of the proposed regulation is to reduce the risk of smelter workers developing lung and skin cancer as a result of exposure. A comprehensive study compiled by the Committee on Medical and Biologic Effects of Environmental Pollutants concluded that "there is strong epidemiologic evidence that inorganic arsenic is a skin and lung carcinogen in man."' In April 1977, the Environmental Protection Agency (EPA) served notice to ASARCO Incorporated that its Tacoma copper smelter and associated arsenic-producing facilities were in violation of State laws which limit sulfur dioxide and particulate matter emissions. This notice followed the Washington State Pollution Control Hearing Board overturning a prior ruling by the Puget Sound Air Pollution Control Agency (PSAPCA) which had permitted a 5-year variance from the State of Washington air quality standards. In December 1977, ASARCO appealed in court the decision of the Hearing Board.

Jan 1, 1980

By Thomas R. Bur

The strain and pressure gage methods for evaluating the relative performance of explosives in rock were compared. This comparison was based on a study of the responses of strain and pressure gages to explosion-generated seismic waves. Several explosives) representing a wide range of detonation pressures) were used. In general the relative performance of these explosives) as determined from amplitude) impulse parameter) and energy parameter measurements) is the same if the compressive portion of the strain pulse and the comparable portion of the pressure pulse are considered. Other similarities and differences of the two methods are also discussed.

Jan 1, 1967

By W. E. Anable

The Bureau of Mines studied the purification of commercially available vanadium in the 100-kw electron-beam furnace. Purification studies were conducted on a 100-gram button scale by melting and holding the liquid vanadium at temperatures ranging from 2,060° to 2,080° C at pressure of 5(10)-5 torr for periods ranging from 5 to 20 minutes. The effect of doping vanadium with carbon and metallic additions was determined. This study demonstrated that hydrogen was readily removed to 3 ppm or less, oxygen and carbon were reduced to less than 100 ppm each, and the metallic impurities were reduced Co the range of 10 to 500 ppm. The nitrogen content was not reduced in any of the buttons; rather, the nitrogen concentration generally increased as samples were held for successively longer periods. Oxygen was removed much faster and more completely when vanadium was doped with small carbon additions or one of several dopes prior to melting.

Jan 1, 1967

By Raymond M. Stateham

A portable, handheld infrared scanner has been used to detect abnormal surface temperature on dumps of flood-generated trash near Wilkes-Barre, Pa. Three of eight dumps examined had thermal anomalies on the surface, indicating temperature buildup at depth. The anomalies found with the scanner were verified by measurements with a thermocouple probe or a carbon monoxide detector. One week after the investigation was completed, open fire broke out at the site of one of these thermal anomalies; about 6 weeks after the investigation, a thermal anomaly in another dump was verified when a trench was excavated in the dump.

Jan 1, 1973

By D. A. Reynolds

THIS PAPER gives results of an investigation of the composition and carbonizing properties of coals from the Beckley bed, Caretta No. 5 mine, Susanna, McDowell County, and Glen Rogers No. 2 mine, Glen Rogers, Wyoming County, W. Va. The investigation included BM-AGA carbonization tests at. 800° and 900° C. and various chemical and physical tests designed to evaluate agglutinating, plastic, and expanding properties of coal. Both coals were of low-volatile bituminous rank, and each was blended with 70 and 80 percent high-volatile A coal from the Pittsburgh bed, Warden mine, Allegheny County, Pa. The Beckley bed was 39 to 58 inches thick at three points in the Caretta No. 5 mine, and the coal was 39 to 49 inches thick. The carbonizing sample contained 83.0 percent fixed carbon on the dry, mineral-matter-free basis. It contained 3.1 percent moisture, 15.8 percent volatile matter, 72.4 percent fixed carbon, 0.7 percent sulfur, and 8.7 percent ash, as carbonized. The ash softened at 2,680° F. The free-swelling index was 7;i, and the agglutinating value was 7.7. This sample fused weakly in the Gieseler plastometer; its blends with 70 and 80 percent Pittsburgh coal attained maximum fluidities of 830 and 600 dial divisions per minute, respectively. The single coal yielded 83.0 percent coke at 900° C. Yields of other carbonization products per ton of coal at 900° C. were: Gas, 9,950 cubic feet; tar, 3.5 gallons; light oil, 1.36 gallons; and ammonium sulfate, 16.3 pounds. Blending with Pittsburgh coal lowered the yield of coke and raised the yields of other products significantly. Caretta coal yielded strong, blocky coke at 900° C., 89 percent of which was plus-2-inch size. Strength indexes of 900° C. coke from 30:70 blends of Caretta No. 5 and Pittsburgh and of Pocahontas No. 3 and Pittsburgh coals were, respectively: 2-inch shatter, 68 and 53; 1%-inch shatter, 90 and 85; 1-inch tumbler, 50 and 53; and %-inch tumbler, 62 and 65. The specific gravity of the 900° C. gas from Caretta No. 5 coal was 0.272, and the heating values were 491 B. t. u. per cubic foot and 2,440 B. t. u. per pound of coal. The blends yielded much richer gas. Yields of tar acids and bases (0.09 and 0.04 gallon per ton, respectively) were within the normal ranges for low-volatile coals. Caretta No. 5 coal expanded 7.5 percent in the sole-heated oven at a charge density of 55.5 pounds per cubic foot. The blends containing 70 and 80 percent Pittsburgh coal contracted 4.8 and 7.5 percent, respectively.

Jan 1, 1953

By D. G. Kuehn

Studies were conducted by the Bureau of Mines to determine the positive ions and neutral species produced in glow discharges of gas streams containing 1.0 percent NO in helium, 29 percent dry air in helium, and 1.06 percent NO in N2, Mass spectrographic measurements were conducted for gas pressures from 2.3 to 10.0 torr and dc currents from 10 to 20 mAo Ion species observed included NO+, N2 +, O2 +, N+, and 0+ with lesser amounts of He+, He2+, and N02+. Variations in various ionic and neutral species with discharge duration were interpreted to be consistent with an electrically induced dissociation of NO to produce N2 and O2. No nitrogen oxides were observed to form in glow discharges of the helium-air mixture.

Jan 1, 1975

By Deborah A. Kramer

An economic and technical evaluation of a proposed process to recover alumina by leaching calcined kaolinitic clay with sulfurous acid is presented in this Bureau of Mines report. After the insoluble portion of the clay has been removed by leaching, monobasic aluminum sulfite is precipitated from the pregnant leach solution by partial hydrothermal decomposition. Further heating completes the decomposition to an impure alumina hydrate. This intermediate is purified in a modified Bayer process, which includes dissolving the alumina hydrate in a caustic solution at high temperature and pressure, then decreasing the temperature and pressure to precipitate alumina trihydrate. Calcining the trihydrate produces the alumina product. A cost estimate was prepared for a plant producing 1,000 tons of alumina per day, 350 d/yr. The estimated operating cost is approximately $475 per ton of alumina. This is substantially higher than a comparable estimated operating cost for the Bayer process of $250 per ton of alumina. The proposed process does not appear economically attractive, even as a method to modify a current Bayer processing plant to use a kaolinitic clay feed. High capital costs and high energy requirements make the process prohibitively expensive.

Jan 1, 1983

By Peter H. Toepfer

Hydraulically emplaced, classified mill sands long have been used for stope fill. Entrained water drains rapidly from this type of fill through openings between the sand grains. Slimes are removed to facilitate drainage of the water, thereby lowering dangerous hydrostatic pressures in the fill. Use of unclassified mill tailing as practiced at the Dayrock mine is a recent development and represents a fundamentally different approach to the problems of inhibiting the development of hydrostatic pressures within the stope fill. At the. Dayrock mine, mill tailing is used to form a densely packed fill of sand and slime particles relatively impervious to additional water.

Jan 1, 1952

By O. C. Blade

"INTRODUCTION This report on the properties of motor fuels sold through service stations in the United States is a continuation of a series of reports made in accordance with a cooperative agreement between the Coordinating Fuel Research (CFR) Committee of the Coordinating Research Council (CRC) 3/ and the Bureau of Mines of the United States Department of the Interior. The first of these reports presented data on motor gasolines sold during the winter of 1935-36.4/ Further reports were issued describing motor gasolines sold during the succeeding sum¬mers and winters to and including the summer of 1941.4/ No reports were made on motor gasolines sold during the winter of 1941-42 and during the summer of 1942. However, starting with the winter of 1942-43, the semiannual reports were resumed.!The present report presents analytical data for 4,544 samples, represent¬ing the products of 124 companies. The samples represented in this report were obtained during December 19146, January and February 19-(. As in previous surveys, the companies covered Ly the survey include both large and small suppliers. Conforming to former reports, the data cover three groups of samples - regular-price, premium-price, and third-grade gasolines.As the number of analyses submitted for samples of third-grade gasoline are not considered adequate to represent this type of motor fuel, data for the analyses have not been averaged, but the individual items are tabulated. The number of samples, items, and brands comprising each group is as follows: Regular-price, 2,368 samples, 319 items, and 113 brands; premium-price, 2,172 samples, 289 items, and 106 brands; third-grade, 4 samples, 4 items, and 4 brands. The meanings of these terms as used in the surveys are as follows:"

Aug 1, 1947

By Richard S. Gaps

The Derby and Alexander Claim, located within the Tunnel Ridge Wilderness Study Area (WSA), has placer gold resources. No lode deposits are known within the area, but lode gold deposits are found within 1 1/2 mi of the WSA. In additon, rock units which contain lode gold deposits north of the WSA are found within the northern portion of the study area. INTRODUCTION The Tunnel Ridge Wilderness Study Area (WSA), CA-030-402, encompasses 4,623 acres of BLM administered public land in Trinity County, California, about 35 mi west-northwest of Redding (fig. 1). Major access to the Tunnel Ridge vicinity is by U.S. Highway 299. Ac-cess to the WSA boundary is by a secondary paved road from Junction City and several light duty dirt and gravel roads (fig. 2). The WSA is on the southwest slope of Weaver Bally Mountain. The topography is rugged with moderate to steep slopes; elevations range from about 1,600 ft to 5,900 ft.

Jan 1, 1983

By J. D. Davis

THIS REPORT gives results of an investi¬gation of the carbonizing properties of coals from Pittsburgh bed, Jamison No. 9 mine, Marion County, W. Va., and from Upper Freeport bed, Bull Run No. 1 mine, Preston County, W. Va. The study included Bureau of Mines-American Gas Association tests at 800° and 900° C. and various chemical and physical tests designed to evaluate the plastic, expanding, and agglutinating properties of coal. A blend of each coal was carbonized in the 500-pound slot oven. The carbonization sample of Pittsburgh coal contained 2.7 percent moisture, 35.8 percent volatile matter, 54.4 percent fixed carbon, 7.1 percent ash, and 0.9 percent sulfur. It contained 60.9 percent fixed carbon on the dry, mineral-matter-free basis and had a heating value of 14,780 B. t. u. per pound on the moist, mineral-matter-free basis. It therefore ranks as high-volatile A bituminous and was blended with low-volatile Pocahontas No. 3 coal. Upper Freeport coal contained 2.8 percent moisture, 27.7 percent volatile matter, 60.9 percent fixed carbon, 8.6 percent ash, and 1.0 percent sulfur, as carbonized. It contained 69.5 percent fixed carbon on the dry, mineral-matter-free basis and therefore ranks as medium-volatile bituminous. It was blended with high-volatile A Pittsburgh coal from Allegheny County Pa.

Jan 1, 1952

By H. F. MILLE, Charles A. Kumke

This paper describes mining operations at the Iron King mine of the Shattuck -Denn Mining Corp. in Yavapai County , Ariz . It is one of a series being prepared by the Mining Division of the Bureau of Mines on mining practices and methods in various mining districts of the United States . The mine and surface plant of the Iron King mine are situated in secs . 15 and 21 , T. 13 N. , R. 1 E. , about 20 miles by State highway 69 east by southeast from the city of Prescott and 1 mile southwest of the mining town of Humboldt on the Prescott -Mayer branch of the Atchison , Topeka & Santa Fe Railroad (fig . 1 ) . A l-mile truck haul brings the mill concentrates (lead and zinc ) to bins on a siding of this line at Humboldt ; the silver -gold bullion is handled separately . Some of the oldest residents in the vicinity of Prescott claim that the original location for the Iron King mine was made in 1880. The earliest recorded production was in 1906-1907 . During the first World War the mine produced fluxing ore for the Humboldt smelter . In 1936 the property was purchased under tax sale , and a mill (140-ton capacity ) was erected in 1938. The capacity of this mill was increased to 225 tons the following year , and a cyanide plant was added in 1940 to treat mill tailings . In 1942 the Shattuck -Denn Mining Corp. purchased the property . A new working shaft was sunk , mine development was speeded , and mill capacity was again increased . The predominating locally formation of this district is a pre -Cambrian schist known as Yavapai schist . The Iron King deposit , which carries gold, silver , lead , zinc , and copper , occurs as a series of lenses in a sheared zone of the pre -Cambrian schist . Down to the 600 -foot level the ore was mined and drawn by the shrinkage method . The cut -and -fill method was adopted for the lower levels . Waste rock for stope fill was provided by block-caving an area on the 600 level . Main haulage drifts were driven in the firm footwall , and crosscuts were driven across the mineralized zone at 100 -foot intervals . Grab samples taken from each car of every working place and channel samples cut every 5 feet in development work are considered sufficient for estimating ore reserves .

Jan 1, 1950

By D. F. Walsh

A study of damping capacity was made on a number of magnesium-base alloys, commercial types and experimental compositions. Hardness and tensile properties were determined, and the microstructure of each alloy was examined. Alloys of low yield strength, in general, possessed high damping ability. A correlation was established between damping capacity and composition.

Jan 1, 1962

By C. A. Herbert

Coal-mine explosions in the United States during the past 10 years ranked third among the causes of coal-mine fatalities and constituted 16.1 percent of the total fatalities. In Indiana, however, during this same period the percentage of fatalities from this cause was much higher than the average percentage for the entire country. It is only through knowledge of the factors that have led to these past explosions that intelligent steps may be taken to prevent similar occurrences in the future. Although information concerning many of the earlier explosions is lacking, an attempt has been made to tabulate the information available in the hope that it may be of assistance in calling attention to some of the principal causes of explosions in Indiana.

Jan 1, 1934

By A. A. Cochran

The objective of the research was to determine the final distribution of cerium additions to steel, their effect on sulfide inclusions, and the usefulness of radiotracer methods in investigating steel problems. Fifty-gram heats of steel were prepared that contained either cerium 141 and nonradioactive sulfur, or sulfur 35 and nonradioactive cerium. These steels were studied by autoradiography, measurements of their surface radioactivities, optical microscopy, and chemical analysis. Samples of the crucibles were analyzed quantitatively for cerium or sulfur by radioactivity counting methods. The addition of cerium to steel melts reduced the size and number of iron sulfide inclusions in the resulting steel. A significant fraction of the sulfur and most of the cerium penetrated into the MgO crucible during the melting operation, The cerium inclusions in steel were identified as cerium sulfide. Radiotracer methods were found to be versatile and highly sensitive.

Jan 1, 1963

By Danny A. Riley, James R. Sanger, Hani S. Matloub, Michael Agresti, David Rowe, Lin-Ling Zhang, Yuhui Yan, Paula Galaviz, Judith Marchant-Hanson, Ji-Geng Yan

Until now there has been controversy about which tests should be performed to diagnose early Hand-Arm Vibration Syndrome (HAVS). Initial screening questions, especially about tingling and numbness, routinely given to patients prior to examinations proved to be a very important tool in the diagnostic process1, 4. However, standardized tests that are simple, quick, valid and reliable are needed to support a diagnosis of HAVS. Purpose: To find the most valid and reliable tests to diagnose HAVS. Material and Methods Five major tests were performed on Group I and Group II. Group I: Control group of 12 volunteers including students, nurses, secretaries and physicians with no history of using vibrating tools (age 20 to 50y, mean age 38.5y; 5male, 5 female.) Group II: 12 workers (age 17 to 65y, mean age 39y; 9 male, 3 female) were sent by a local trade union with a history of using vibrating power tools on their jobs for varying amounts of time (mean 12.2y, from 0.5 to 35y.) Pre-enrollment survey showed that each had more than 4 complaints commonly associated with use of vibrating tools (including numbness, tingling, weakness, pain, finger color or nail changes, temperature change, and difficulty moving.) 1. Sensory nerve conductive tests: Amplitude and nerve conductive velocity (NCV) were evaluated. 2. Cold Stress-Temperature recovery time tests were done on the index finger of the dominant hand following these steps: Confirm water bath is within 4-5º C. Place the finger temperature probe on pad of the index finger of the dominant hand. Record temperature every 15 seconds. Place subject’s hand in the cold- water bath for exactly five minutes. Record temperature every 15 seconds for ten minutes. 3. Blood test: Venous blood was taken by a 21-gauge needle with the yellow collection tube adapter. S-ICAM, Sera Thrombomodulin, Norepinephrine levels were evaluated by Henderson Research Centre, Canada. 4. Finger Sensory Evaluation: Semmes-Weinstein monofilament test and 2-point discrimination tests were performed on bilateral fingers. 5. Digital blood pressure test: blood pressure was measured in bilateral index fingers. Results 1. Median nerve sensory conductive amplitude from palm to wrist : GI: mean 96 ± 31µm; GII: mean 43± 30µm; for dominant hands. GI vs GII: P<0.001

Jan 6, 2006

By R. V. Lundquist, A. E. Morris, E. L. Singleton

This experimental research was performed to determine rate - of - reaction constants on the MnO - C and Mn , C₂ - 3MnO systems at 1,100 ° , 1,150 ° , and 1,185 ° C. Reactions were conducted at atmospheric pressure under controlled flow of purified helium through the furnace chamber . The weight - loss method defined reduction percentages , and reaction products were identified by X- ray methods . The system Mn0 - C followed a linear reaction rate , and experimental results produced an apparent activation energy of 55.8 kcal per mole of Mn0 . The system Mn, C - 3Mn0 followed a parabolic rate of reaction law and yielded an apparent activation energy of 114.4 kcal per mole for the reaction .

Jan 1, 1964

By A. L. Engel

This report is a compilation of results of preliminary tests on scheelite (tungsten) ores and tailings. These investigations were made to assist in establishing satisfactory treatment methods for small-scale concentrator operations, or to indicate a. method for conserving previously lost mineral values in old tailings, if possible. A discussion of test procedures is included, as it was felt that this would add to understanding the results reported under the several projects. The treatment of scheelite ores has become more or less standardized. Important differences occur in textures of ores from various mining districts. However, and this must be considered when planning ore-dressing operations. In most of the present investigations, only a limited amount of work was done, usually just enough to answer a specific question in regard to a particular ore or concerning local conditions. Two methods of treatment included gravity concentration, magnetic separation, and flotation.

Jan 1, 1952