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By H. E. Powell

This study was made to determine the capabilities and limitations of the hydrocyclone for separating quartz sand from impure clays, Optimum operating conditions for beneficiating typical subgrade clays were determined. Estimates are furnished for installation and direct operating costs of hydrocyclones in such separations. Laboratory models of commercial hydrocyclones were used to beneficiate a suite of fire clays including plastic, semiflint, and flint types, all of which were contaminated with quartz in amounts ranging from 3 to more than 62 percent. Results show that this technique is not limited to a single type of clay but is applicable to clays ranging from plastic through flint, Under proper conditions use of this technique will result in good separation of the sand and good recovery of a useful clay mineral concentrate. Rejection of quartz from the clays investigated ranged from a low of 82.4 percent with an alumina recovery of 71.2 percent to a high of 99.0 percent with an alumina recovery of 85.6 percent.

Jan 1, 1963

By Robert W. Geehan

The Bureau of Mines has been developing deposits of critical and essential minerals in the United States since 1939. A preliminary examination of the Union lead mine was made in November 1944 and January 1945 by W. T. Benson, a Bureau of Mines engineer, who recommended development by diamond drilling. The Bureau conducted a drilling project at the mine from February 12 to May 16, 1947. The property is in sec.12, T. 17'N., R. 19 E., Mount Diablo Base and Meridian, in. southern Washoe County, Nev., about 15 miles south of Reno. The Union lead mane, also known 4s the Commonwealth mine, has been an intermittent producer of zinc-lead-silver ore since 1860. During World War II, ore was shipped to smelter& near: salt Lake City, Utah. The Bureau drilled 21 diamond-drill holes having a total length of 1,549 feet and 20 long percussion-drill holes with a total length of 359 feet. The program was designed to test for horizontal and vertical extensions of the ore body and to prospect for parallel ore bodies. As a result of this program, extensions of the ore zone were established, but no parallel ore-bearing structures were found. The areas drilled were limited by drill sites available.

Jan 1, 1950

By W. J. Wuest

This U.S. Bureau of Mines report presents an overview of ground control considerations associated with cutter roof failure. Many of the relevant U.S. and international research studies since the late 1940's are reviewed, and summaries of recent design guides are included. Factors affecting cutter roof, such as underground stress field and rock structure around the entry, are described. Strata control techniques are also outlined. These techniques are divided into three sections: artificial support, mine structure design, and multiple-seam extraction. Other subjects covered in the report include monitoring and prediction, effect of geologic features, and mapping of adverse mining conditions. The emphasis of this report is on practical considerations; theoretical discussions are minimal.

Jan 1, 1994

By Alex C. Smith

This report describes laboratory studies conducted by the Bureau of Mines on the spontaneous combustion of U.S. coals. Approximately 11 pet of U.S. underground coal mine fires are attributed to spontaneous combustion. The relative self-heating tendencies of 24 coal samples were evaluated in an adiabatic heating oven. Minimum self-heating temperatures (SHT's) in the oven ranged from 350 C for a lignite and high-volatile C bituminous (hvCb) coal, to 1350 C for two low-volatile bituminous (lvb) coals. An empirical expression was determined predicting a bituminous coal's minimum SHT in the adiabatic oven based on the coal's dry ash-free oxygen content. Several factors that can affect the self-heating process were also evaluated. The self-~eating tendency of a coal increased when the coal was dried and exposed to humidified air, and was dependent on the particle size and oxygen concentration of the air. A new moderate-scale apparatus is described, in which the self-heating tendencies of larger coal samples, 3 kg, can be evaluated. The minimum SHT's of two coals were determined and the results were in good agreement with those found in the adiabatic oven. Finally, results of a test in the moderate-scale apparatus indicated a strong dependence of the self-heating rate of a low rank coal on the moisture content of the air.

Jan 1, 1987

By Lawrence G. Houk

Monazite sand is the only commercial source of cerium, other rare-earth metals and thorium. Although used in rather small quantities, it is essential to many industries. The United Unites is entirely dependent upon British India and Brazil for its supplies. Monazite sand or sand imported under the tariff classification for monazite was shipped to the United States in greater quantities, in 1940 than ever before. About 75 percent of our imports was from British India and most of the remainder from Brazil. If need be, Brazilian production can be expanded to supply all of our essential requirements, and the theater of war expands in the Pacific Brazil may supersede India as the principal source. PHYSICAL PROPERTIES The mineral monazite is generally honey yellow or may vary from greenish yellow to clove brown. The grains are small and resinous in luster, and range from subtranslucent to opaque. The specific gravity varies

Jan 1, 1943

By A. C. Fieldner

The annual reports of the research and technologic investigations conducted by the Bureau of Mines on the occurrence, properties, mining preparation, and uses of coal, of which the present report is the seventh,4/ are intended to be brief summaries of progress. They are guides to the current work and publications of the Bureau but do not replace the more complete reports published by individuals and groups of workers on specific problems. The annual reports present the results of tests, often in advance of publication in other forms, but original contributions in research are reserved for initial publication by their authors. A survey of the accomplishments of the Bureau in research and technologic work on coal during the 5 year period 1935-40 has been made available in the form of a bibliography.5/ This supplements a similar bibliography on this subject that covers the first 25 years of the Bureau, 1910-35.6/

Jan 1, 1943

By Bruce Maxwell

The deformation modulus of coal mine pillars theoretically can be reduced by drilling holes in advance of the mining face. This reduction of modulus along the edge of the pillar has the effect of decreasing the stress concentration in the roof; control of roof caving is thereby predicted. Initial field work indicated that a high horizontal stress field existed at the field test site: Subsequent field work was undertaken to confirm the high horizontal stress field and to attempt to relieve the horizontal stress in the immediate roof. A method of softening pillars in conjunction with normal mining activity was developed. Instruments to measure horizontal roof strain, roof parting, roof tilt at the rib, and changes in vertical and horizontal stress in the roof and in the coal were used. These instruments were installed in both softened and unsoftened entries and in locations to indicate the effect of vertical slots in the roof. Significant stress reduction due to pillar softening was indicated, but the effect of this reduction on roof stability was not established. The vertical roof slots relieved the horizontal stress in the immediate roof very effectively, and observations of roof conditions indicated that the slots definitely improved roof stability.

Jan 1, 1977

By S. F. Mauser

This report describes the study of factors which affect medium voltage (661 - 1000 volts) trailing cable splices used in underground coal mines. Improvements in quality, dependability, and design of splice kits and shop splices are presented in the study results and recommended guidelines and regulations. Recommended research programs are included which describe approaches for development of the recommended guidelines and regulations for medium voltage trailing cable splices. The basis for the conclusions and recommendations presented in this report is included in three appendices which describe a survey, splice examination, and general requirements development prepared during the progress of this study.

Jan 1, 1977

By Grace N. Broderick

U.S. supply and demand data for coal, by States and regions, were tabulated for the years 1960 and 1965. Estimates are provided of State-by-State quantitative data for the coal industry that can be integrated into State and regional energy balances by source, form, and consumer sectors, and used for estimates of interstate and interregional energy flows. The tables give an estimated total supply of coal available for consumption, and also report the distribution of the supply among the major consuming sectors (household and, commercial, industrial, transportation, and electricity generation). To enable comparison of coal data with those for other energy forms, tonnages were converted to British thermal units (Btu). Future energy analysis studies could be facilitated by changes in the categorization of information collected on the coal industry. The data shown are based primarily on Bureau of Mines source material.

Jan 1, 1969

By Maria I. De Rosa

The U.S. Bureau of Mines conducted a study to determine if correlations exist between the chlorine or nitrogen contents of materials and the hydrogen chloride (HCI) or hydrogen cyanide (HCN) concentrations evolved during the thermal decomposition of these materials. Hydrogen chloride, hydrogen cyanide, and carbon monoxide (CO) were found to be the primary toxic gases evolved during the combustion process. The experiments were carried out in a 20-L furnace with 1-g samples. The furnace temperature, rising from ambient, was set at 1,000 °C with an airflow of 10 L/min. The variables measured were the gas loads (milligrams per gram) of HCI, HCN, CO, and CO2 (carbon dioxide); CO and CO2 concentrations as a function of time were also measured. Other variables included the average concentrations of submicrometer smoke particles and particles' average diameter, mass of particulates, sample and furnace temperatures, and sample weight loss. The data indicate that there are significant correlations between the percentage of chlorine or nitrogen contained in the original samples and the HC1 or HCN concentrations evolved during the combustion of the materials. These correlations may be used to predict and evaluate a material's toxic hazard during combustion.

Jan 1, 2010

By A. T. Coumbe

During 1953-55, 31,105 miles of pipe for transporting crude petroleum and refined products was laid in the United States, a total slightly below that of the prior 3-year period, according to data compiled by the Bureau of Mines, United States Department of the Interior. The added mileage consisted of 22,571 miles of new pipe, representing about 2,163,807 tons of steel, plus 8,534 miles of secondhand pipe, equivalent to about 419,849 additional tons of steel. During the 3-year period, 13,069 miles of pipe was taken up. By January 1, 1956, the Nation had 188,540 miles of pipeline, an 11-percent gain over the 1952 total of 170,504 miles. The greater use of larger diameter pipelines indicated in recent surveys has continued, as the mileage for sizes 12 inches and over increased from 13 percent of the total mileage at the close of 1952 to 16 percent 3 years later. Crude-oil trunklines 12 inches and over in diameter gained 24 percent during 1953-55, and these larger lines represented 30 percent of the total mileage compared with 25 percent at the close of 1952. Furthermore, the mileage for crude-oil lines less than 12 inches in diameter declined 2 percent and made up only 70 percent of the 1955 total against 75 percent n the previous survey. Product Lines 8 inches and over increased 43 percent from 1952 through 1955 and composed 70 percent of the total mileage compared with 66 percent in 1952.

Jan 1, 1956

By James C. Barker

The Bureau of Mines evaluated the tin development potential of the uplands between the Kanuti and Hodzana Rivers from 1978 through 1980. Chemical and petrologic data indicate that local granitic intrusions are generally similar to "tin granites" that contain tin deposits elsewhere. The tin mineral cassiterite (SnO2) was identified in chlorite-rich greisen from the Sithyiemenkat pluton. Greisen zones are located near the intersections of high-angle, linear structural features, and samples contain up to 0.23 pct Sn. One bedrock exposure of greisen is 10 to 15 ft wide. Although some lode mineralization is present, the deeply eroded nature of the region suggests larger tin-bearing cupolas may have existed prior to erosion. Extensive stream gravel deposits have not been affected by glaciation, and potential exists for placer tin deposits. Especially favorable is a large semiclosed basin drained by the Kanuti Kilolitna River. Heavy mineral concentrates collected from surface alluvium in the Kanuti Kilolitna River valley contained up to 51.2 pet Sn (0.02 to 0.4 lb/yd3 Sn), up to 5 pct W, up to 0.4 pct Cb(Nb), and up to 0.1 pct Ta. The concentration of heavy minerals is expected to in- crease with depth. Detailed mapping and extensive surface and subsurface sampling will be needed to quantify the mineral development potential of the lode and placer tin deposits in the uplands.

Jan 1, 1986

By Michael J. Beus

This Bureau of Mines report describes field investigations conducted in the Coeur d'Alene mining district of Idaho to obtain data on rock stress and physical properties. The resulting information has been utilized as input to detailed finite-element analyses to establish structural design criteria for deep-vein mine shafts. Measurement techniques include the Council for Scientific and Industrial Research biaxial and triaxial strain cells, the U.S. Geological Survey solid-inclusion probe, and the Colorado School of Mines dilatometer. Physical property testing was conducted in the laboratory on core obtained from each test site. Limited in situ physical property tests were also conducted. Reason-able success was obtained with the CSIR equipment, which was considered the most suitable for stress measurement in the study area. Test sites ranged in depth from 1,200 to 7,700 feet and are described in detail. The stress data were reduced by least-squares linear regression techniques to enable prediction of vertical and horizontal stresses to 7,500 feet. Ratios between the horizontal stresses as utilized for shaft design varied considerably, and a hydrostatic condition is the exception, based on Bureau measurements. Physical properties also varied widely, due to the complex geologic structure. Analyses of the data in terms of the tectonic history of the area show reasonable correlation. Data from previous rock mechanics investigations from the Coeur d'Alene district were also compiled and presented as part of this report to justify any generalizations regarding stress conditions and physical properties of the district as a whole.

Jan 1, 1980

By D. A. Elkins

Design plans and detailed cost estimates of mining and treating ore from Maggie Canyon deposit by two alternative methods which can be used in the event of a sudden need to exploit this resource are given . Lower costs are estimated for the operation employing oil - emulsion flotation . The total capital investment required for this operation is estimated at $ 11,750,000 . Assuming an 85 percent recovery in mining , 55.6 pct of the manganese in the ore reserve would report in 153,333 tons of ferromanganese containing 75 pct manganese . The production cost for the 5 - year operation would be about $ 245 per ton of ferromanganese . The total annual operating cost would be approximately $ 7.5 million , distributed , in pct , as follows : Mining 11.9 , milling 24.4 , sintering 9.9 , smelting 47.2 , hauling ore and sinter 2.8 , and general offices 3.8 . Recovery and costs are both higher for the operation employing dithionate leaching . In this operation the required investment is about $ 17,220,000 . Manganese recovery would be 67.6 pct in 186,160 tons of ferromanganese . Production cost would be about $ 284 per ton of ferromanganese . The total annual operating cost would be about $ 10,575,000 , distributed , in pct , as follows : Mining 8.4 , milling 44.4 , sintering 7.4 , smelting 34.7 , hauling ore and sinter 1.3 , and general offices 3.8 . Potential process modifications might reduce the operating cost of the first operation by as much as 7 pct and that of the second operation by as much as 9.5 pct , but exploitation of the deposit by the techniques studied is not economical today .

Jan 1, 1964

By Michael S. Miller

In 1986 and 1987, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied the nine separate parcels that comprise the 4,330-acre South Warner Contiguous Wilderness Study Area in order to evaluate their identified mineral resources. The nine parcels are along the east side of the South Warner Wilderness. They are, from north to south, the Granger, Milk, Cottonwood, Owl, Hornback, Eagle, Emerson, Barber, and Van Riper parcels. The Wilderness Study Area is underlain by basaltic, andesitic, and rhyolitic volcanic rocks and by sand and gravel deposits. Low-grade metamorphism is widespread in the volcanic rocks, with quartz, zeolites, datolite, chlorite, and calcite locally abundant in veins and amygdules. The rocks have been displaced by the mountain-front Surprise Valley fault and by crosscutting high-angle faults.

Jan 1, 1988

By Curt D. Jr. Edgerton

This study was made to determine trends in fresh water usage by California petroleum refineries, to Forecast fresh water requirements to 1975, and to evaluate water conservation practices. Statistical data used in the study were obtained largely from published sources and from records of selected companies. An adequate sampling of the State's refining capacity was obtained, and the data were extrapolated to the total California refining capacity. A breakdown of the data was then made on the basis of the following refining regions: (1) the Los Angeles Basin and Southern Coastal region, (2) the Southern San Joaquin Valley, and (3) the San Francisco Bay area. An unpublished forecast of crude oil input to refineries by a major oil company operating on the West Coast was used as a basis for predicting fresh-water usage. The 1963 fresh water intake by California petroleum refineries was 84 million gallons per day. This is expected to increase to 128 million gallons per day by 1975. The fresh-water to crude-oil ratio is increasing in all regions except the Southern San Joaquin Valley. At present, the supply of fresh water available to almost all of the State's petroleum refineries, mostly from surface sources and company-owned wells, is adequate, although shortages may develop within the foreseeable future. Present conservation methods are centered around the following four objectives: (1) minimum intake of fresh water of the lowest possible quality commensurate with sound technologic practice; (2) optimum recirculation (3) proper treatment before discharge; and (4) substitution of air cooling for water cooling.

Jan 1, 1965

By E. P. Carman

This: report gives data on the installation and operation of a packaged-unit heat-pump installation in a residence in McLean, Va., a suburb of Washington, D. C. The original equipment, installed in January 1947, was one of the first of 50 experimental Marvair units manufactured by the Muncie Gear Works, Inc., Muncie, Ind. The compressor unit of this installation was replaced by the company in September 1947, with a modified commercial model. The commercial unit and the original pump and fan accessories have been used as the sole means of heating (and cooling in summer! the. residence for the subsequent five winters and summers. The conclusions and data given herein, therefore, cover 6 winters sad 6 summers of heat pump operation, including 1 winter when temperatures averaged below normal for 2 months and the following summer when temperatures were above normal.

Jan 1, 1953

By E. W. Dean

A previous report of the Bureau of Mines* has supplied data for the physical and chemical properties of samples of crude petroleum produced in the eastern fields of the United States. It was issued as a preliminary chapter of a bulletin which is to cover the results of a survey of the entire country. The present report is a second preliminary chapter including figures that are available for the producing fields of the Rocky Mountain district. Work is being continued. with a series of samples from the States of Kansas and Oklahoma which will be described in a third preliminary chapter, to appear at a subsequent date. Acknowledgments. The obtaining of samples was rendered possible through the courtesy of representatives of a number of producing and refining companies operating in the Rocky Mountain district. The Bureau hereby acknowledges its appreciation of the hearty spirit of cooperation that was universally encountered.

Jan 1, 1921

By L. H. Adami

Heats of formation were obtained for four anhydrous crystalline sodium borates by hydrochloric acid solution calorimetry. The heats of formation at 298.15° K from the elements are NAB02, -233.2 ±0.6 kcal/mole; Na2B07, -786.4 ±1.0 kcal/mole; NaB305, -549.9 ±0.8 kcal/mole; and Na2B6013, -1,412.5 ±2.0 kcal/mole, The heats of formation from the constituent oxides are NaB02, -31.5 ±0.8 kcal/mole; Na2B407, -78.8 ±1.3 kcal/mole; NaB305, -44.1 ±0.8 kcal/mole; and Na2B8013, -96.7 ±1.5 kcal/mole.

Jan 1, 1968

By A. T. Coumbe

The first national survey covering sales of fuel oil by States and principal uses was made in 1926 by E. B. Swanson of the Bureau of Mines (then under the U. S. Department of Commerce) under a cooperative agreement with the American Petroleum Institute. This annual study, covering the market for fuel oil, was made through 1930 with the financial help of the institute bat has since been continued by the Bureau up to the present time. The scope and coverage of the survey have gradually changed over the years as new uses for fuel oil have been found and new products have come into importance resulting in market expansion. Range oil (No. 1 fuel oil or kerosine) came into use for cooking and space-heating daring the depression era in New England, and it was first reported as a total in the 1931 survey. In 1934 the sales were compiled on a State basis. State totals for distillate fuel oil, Diesel fuel, and residual fuel-oil sales were first shown for 1934 and by principal uses and States in 1937. Kerosine deliveries by States and main uses were also released for the first time in 1937.

Jan 1, 1952