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By F. R. Cattoir

This Bureau of Mines study investigated molten salt electrorefining for beneficiating low-grade, high-carbon ferrochromium products which can be readily produced from domestic chromite concentrates. A second objective was to refine commercial ferrochromium into low-iron chromium products. Electrorefining of both types of ferrochromium in molten CaC12-NaCl-CrC12, CaCl2-MgC12-CrCl2, or KC1-LiCl-CrCl2 electrolytes produced chromium-iron products with virtual elimination of other impurity elements and some lowering of the iron content, Over 90 percent of the chromium present in the feed materials was recovered. The electrodeposited products were upgraded further by magnetic separation techniques into chromium containing less than 5 percent iron. The technical feasibility of preparing a premium chromium product from a low-grade, high-carbon ferrochromium made from domestic chromite was demonstrated. Chromium virtually free of carbon, oxygen, and silicon from high-carbon ferrochromiums was produced. In addition, the amenability of three commercial grades of ferrochromium to electrorefining and magnetic separation for preparing chromium metal containing less than 5 percent iron was determined.

Jan 1, 1969

By E. C. Lane

This paper on the physical and chemical properties of crude oils from California fields is one of a series of reports on the oil-producing districts of the United States. The paper includes a short discussion of results, tabular data, and individual analyses of 16 California crude oils. Analyses of other oil from California have been published in Reports of Investigations 25954/, 26085/, 28466/, and 30747/. The samples were obtained by members of the San Francisco office of the Bureau of Mines. The collecting of the samples vas facilitated by the courtesy of representatives of oil companies in California.

Jan 1, 1937

By E. C. Lane

This paper on the physical and chemical properties of crude oils from California fields is one of a series of reports on the oil-producing districts of the United States. The paper includes a short discussion of results, tabular data, and individual analyses of 16 California crude oils. Analyses of other oil from California have been published in Reports of Investigations 25954/, 26085/ 28466/, and 30747/. The samples were obtained by members of the San Francisco office of the Bureau of Mines. The collecting of the samples vas facilitated by the courtesy of representatives of oil companies in California.

Jan 1, 1937

By W. H. Oppelt

To provide a relatively structurally stable form of dried lump lignite, two North Dakota lignites from Mercer County were dried by the Fleissner process in an atmosphere of saturated steam at 200, 300, and 370 p.s.i.a. pressure, corresponding to steam temperatures of 382°, 417°, and 437° F., respectively. Two series of experiments were made at each test pressure with the individual lignites. In one series, the autoclave was preheated to the processing temperature before charging the lignite; in the other the lignite was charged into the autoclave at room temperature. In each case, heat losses were determined by blank tests of steam consumption over a similar operating cycle with the empty autoclave. The degree of moisture removal and net steam consumption were calculated from material balances. The amount of water removed as a liquid from the two North Dakota lignites during the heating and steaming periods was compared with results calculated from previously published data on drying Austrian lignite and Australian brown coal. These lignites, covering a wide geographical area, had original moisture contents ranging from 35 to 49 percent. The Austrian lignite and Australian brown coal are considered to be of Miocene Age, and the Dakota lignites belong to the Paleocene.

Jan 1, 1955

By Stephen M. Jasinski

The development and industry adaptation of advanced technologies have led to many important uses for bismuth and its compounds. Bismuth-base alloys are essential for manufacturing jet engine turbine blades, lenses, and various safety devices, such as fire-protection sprinklers. The addition of bismuth to iron, steel, and aluminum imparts properties to these metals that makes them useful in diversified applications. Bismuth is also used widely in medicine, pigments, and electronics. The United States relies heavily upon imports from South America and Europe to meet its demand for bismuth, which is recovered chiefly as a byproduct of lead processing.

Jan 1, 1992

By E. Chin

Although Japan is a major producer of crude steel, it is poor in industrial raw materials. This Bureau of fines report describes Japan's raw material needs for chromium, cobalt, manganese, nickel, and tungsten to produce ferroalloys and alloy steels. Japanese imports of these ores or metals by quantity and source are given for 1972-81, inclusive, to indicate (1) the changes in the consumption and supply pattern, and (2) the degree of Japan's dependence on foreign sources. This report also describes measures implemented by Japan to reduce the risk- of supply interruption, and discusses the possible implications of supply shortages.

Jan 1, 1983

By P. T. Brooks

A process for extracting 69 percent of the vanadium from weathered Nevada dolomitic shale containing about 1 percent V205 was developed on a laboratory scale by the Bureau of Mines. The process essentially is comprised of salt roasting, leaching with dilute sulfuric acid, solvent extraction, and precipitation of vanadium as ammonium metavanadate. Carbonaceous unweathered shale was less amenable to treatment. A preliminary cost estimate for mining and processing 1,500 tons per day of weathered shale indicated a production cost of about 1 dollar per lb of V205. Considering recent sales at nearly $1. 75 per lb of contained V205, larger scale testing to obtain more definitive process design and evaluation data may be warranted.

Jan 1, 1974

By Edward W. Parsons

Conventional rock-bolt anchors often fail when installed in weak formations. The purpose of this work was to develop an anchor that would utilize an explosive charge to secure anchorage in any type of rock. Laboratory work to develop a rock-bolt anchored by explosive forming was initiated using rock-bolt models which had a drilled explosive chamber and were composed of various metals. This was followed by the use of several types of seamless tubing which were expanded with a water-coupled explosive capsule. By attaching a length of solid bolt to the anchor tube, a prototype explosive-anchored rock bolt was made. More than 150 laboratory models were expanded during this phase of development, During two field tests in underground mines (A and B) and one in an open- cut mine (C), 87 explosive-anchored bolts, 9 slot-and-wedge bolts, 2 bolts anchored with expanding grout, and 28 expansion-shell bolts consisting of three types of shells were installed and subjected to pull tests. The field tests were run to determine the effects of variables such as the amount and placement of the explosive charge, design changes in the bolt, and the effect on anchorage of different pull-test techniques. The field tests revealed the following: Mine A. The explosive-anchored rock bolt was feasible, but changes were necessary in bolt materials and in some details of bolt design. Mine B. The design and materials of the bolt gave excellent results in hard fractured rock, but no information was obtained concerning variations in the dimensions of the anchor unit or in the explosive charge. Nine C. Varying the explosive charge to produce a beaded surface on the bolt tube and tightening of the anchored bolt before pull-testing were found to increase significantly the anchorage obtained in soft ground.

Jan 1, 1963

By Joseph Gersic

In 1989-90, the Bureau of Mines appraised selected high resource potential areas containing gold, rare-earth-element, or pegmatite deposits in or near the Black Hills National Forest. Available mineral resource data were used to construct mine and mill models and to compute discounted cash-flow rate-of-return analyses. Using this information, the economic feasibility of possible operations and probability (in the nonmathematical sense) of exploration and development within the next decade were assessed. High exploration and development probabilities are forecast for gold deposits around existing and permitted mine areas near Lead-Deadwood and west of Galena. The area east of Galena has low to moderate exploration and development probability; the Rochford area has low to high exploration probability and low to moderate development probability; the Keystone area has low to moderate exploration probability and low development probability; the Medicine Mountain area has moderate to high exploration and low to moderate development probabilities. Exploration probability in the Bear Lodge Mountains area is high for rare-earth elements and gold; development probability is low. Exploration probability for gold in the Mineral Hill area is low to moderate; development probability is low. The current level of activity associated with pegmatite mining in the Black Hills would probably not change significantly in the next decade; both exploration and development probabilities are low to moderate.

Jan 1, 1990

[In presenting this list of permissible explosives and blasting devices, the Bureau of Mines desires to call attention to pages 17 and 23, outlining the conditions in use under which, and only under which, the explosive or blasting device is permissible. In view of publications recounting trade practice favoring the use of a blasting device without stemming, particular emphasis is placed upon condition 4 on page 17 and condition 2 on page 23. An explosive or a blasting device enumerated in the permissible lists of thin Bureau is not permissible in use unless it is properly confined with clay or other incombustible stemming.]

Jan 1, 1941

In presenting this list of permissible explosives and blasting devices, the Bureau of Mines desires to call attention to pages 17 and 23, outlining the conditions in use under which, and only under which, the explosive or blasting device is permissible. In view of publications recounting trade practice favoring the use of a blasting device without stemming, particular emphasis is placed upon condition 4 on page 17 and condition 2 on page 23. An explosive or y blasting device enumerated in the permissible Lists of thin Bureau is not permissible in use unless it is properly confined with clay or other incombustible stemming.

Jan 1, 1941

By Louis A. Panek

Determining the change of stress in rock based on measurements of the deformation of a drill hole is a procedure that is increasing in popularity. A closely related procedure involves the applicat10n of this principle to determine the existing stresses in a rock medium, by cutting free (core drilling) an annulus containing the drill hole. In this Bureau of Mines report, expressions are derived from which one can calculate the stress ellipsoid--the three-dimensional change of stress, or the existing three-dimensional stress field, as the case may be. Study of these equations shows that the stress components in three dimensions can be determined by measurements in only two drill holes, and yields general principles that are useful in planning an efficient program of drilling and measurement. Procedures are given for calculating the least squares estimates of the stress components and their standard errors, and for evaluating or comparing calculated values by means of standard statistical inferences.

Jan 1, 1966

By A. L. Engel

This report describes results of laboratory-scale experimental treatment of nine ores containing gold and silver, including samples of products of previous plant treatment, from ore deposits in California and Nevada. The samples treated were taken by engineers of the Bureau of Mines during investigations of these ore deposits. The information reported is of interest for development of the mining districts represented or in future Investigations of similar ores from other sources. The treatment methods were as simple as possible. More complicated treatments were tried when required, The applicability of the methods and their limitations in treating the ores are shown by the data in this report. The following treatment methods were employed in the experiments described: Screen analyses were made to determine distribution of values in various screened-sized portions of crushed ore, or to determine optimum size to which a particular ore should be crushed or ground to liberate values, and some-times to determine residual values in various-sized portions of treated material.

Jan 1, 1961

By T. A. Hendrickson

The Bohemia district, situated about 30 miles southeast of Cottage Grove, Oreg., in the Calapooia Range, has been the major producer of lead and zinc in Oregon. Sporadic production has been Maintained from the district since its early discovery about 1858. In 1942, a selective-flotation mill was built at the Champien mine, which operated for only a short time and was forced to close because of the war and lack of labor. The Champion mill reportedly has been operated as a custom mill for the treatment of ore from the Musick and Helena mines, located in the district sometime in the past. This report summarizes the results of laboratory ore-dressing studies made on ore samples from the Musick and Helena Mines.

Jan 1, 1951

By H. Kenworthy

A zinc-pyrite ore from the Gray deposit in Jo Daviess County, Ill., was successfully concentrated on a laboratory scale. Initially, drill cuttings were submitted for separation of zinc and iron concentrates. Subsequent to mine development, a large sample of coarse ore was submitted to ascertain its amenability to sink-float treatment to produce a low-grade zinc-iron concentrate and discard a clean tailing. The samples of ore were submitted to the Rolla Metallurgical Branch by the Mining Division of the Federal-Bureau-of Mines. They were obtained during the recent war as a part of the extensive government program to increase metal production through exploration for new mineral deposits and investigation of old mineralized areas. The first sample consisted of about 3,000 pounds of drill cuttings collected, during the Bureau?s churn and diamond- drilling program. The second sample was taken at a later date, after Tri-State Zinc, Inc., had opened the deposit and commenced milling the ore. This sample consisted of a ?ton-of mill feed crushed through 2 inches and collected over a period of 3 days.

Jan 1, 1949

By G. S. Scott. R. L. Grant

Ammonium nitrate (NH4NO3), a white crystalline chemical compound composed of 35 percent nitrogen, 60 percent oxygen, and 5 percent hydrogen, has again attracted attention, due largely to the recent catastrophe on April 16 and 17, 1947, at Texas City, Tex. The fire and subsequent explosion on the steamship Ocean Liberty, outside the harbor of Brest, France, on July 28, 1947, has fur- ther increased the interest in the properties of ammonium nitrate. As a result of the Texas City disaster, several laboratories have undertaken research to determine more certainly what causes ammonium nitrate to detonate and under what circumstances. This is not the first time that ammonium nitrate has been involved in a disaster, and its properties reviewed from the standpoint of safety. The disaster at Oppau, Germany, in 1921, which involved an equimolec- ular mixture of ammonium nitrate and ammonium sulfate, prompted an intensive study in Europe and in America. In the United States the properties of am- monium nitrate are now of especial concern because very large quantites are being manufactured and shipped in interstate commerce and abroad. Many an- monium nitrate factories, which were built during the war, will manufacture increasing amounts of this compound for use as a fertilizer. It is the purpose of this report to present a brief summary and biblio- graphy of the published experimental facts about the properties and behavior of ammonium nitrate. The reader is referred to original publications for greater details of the investigative work, and for theoretical discussions. This report also includes a survey of ammonium nitrate fertilizer of the type involved in the Texas City explosions. In the past, authorities have not always agreed on the degree of hazard involved in the manufacture and handling of ammonium nitrate, as the following quotations from the literature indicate: Munroe (82) quoted the following from Turner's Chemistry (a book pub- lished in 1835): "When this salt is exposed to fire, it liquefies, emits aqueous vapor, dries and detonates." Berthelot (14) in his book, Explosives and Their Power, 1983, wrote: "Ammonium nitrate from the point of view of its volatility, and cn account of many considerations, may be regarded as a typical explosive substance."

Jun 1, 1948

By S. H. Ash

A CLAY, sand, and gravel deposit known as the "buried valley" of the Susquehanna River is situated in the Northern field of the anthracite region of Pennsylvania near Wilkes-Barre. The presence of this buried valley and the uncertainty regarding the extent and physical condition of the water-bearing valley-fill deposits have made great care necessary in mining operations to avoid breaking the strata between the mine workings and the valley-fill deposits to the extent that inundation of the mine workings would follow. The principal factor that threatens to cut short the life of the anthracite industry, to curtail production, and to affect the economic structure of the people and business dependent on anthracite for their livelihood is inundation of anthracite mines (6,7).3

Jan 1, 1950

By David E. Swanson

The U.S. Bureau of Mines undertook a basic investigation of collimated abrasive water-jet behavior because a more complete understanding of the fundamental process may lead to further technical advances. Laboratory experiments used 2-mm water-jet nozzles and new entrainment apparatus to analyze collimated abrasive water jets operating under varied conditions. Maximum water pressure was 69 MPa to permit use of conventional hoses with a burst-to-operating-pressure ratio of 4. Nozzle and induction line pressures, abrasive induction rates, and jet reactive thrust forces were recorded for each operating condition. Average jet velocity and power were determined from component mass flow rates and reactive thrust force measurements. Relative velocity and cross-sectional distribution of abrasive particles were determined using impact analysis techniques. Other jet characteristics were determined photographically. Properties of free water jets, collimated water jets, and collimated air-water jets were determined for comparison.

Jan 1, 1989

By Robert H. Ridgway

This circular outlines salient facts regarding the pyrites industry of the United States and the world. It is founded chiefly upon published information available in the literature of the subject. The United States Bureau of Mines has in its files additional and more detailed data upon many of the subjects presented very briefly here, and will endeavor to assist the mineral industries and the public by giving further information in response to individual inquiries. The bureau will welcome comments, criticisms, and contribu- tions of data that may assist in making later editions of this circular of information more accurate, or may aid in developing more fully the files pertaining to pyrites.

Sep 1, 1931

By Patricia J. Leonard - Mayer

A Bureau of Mines surface resistivity method has been used to determine the joint strike and coefficient of anisotropy of jointed , nearsurface formations at five study areas . The field studies demonstrate the use of rotated , or azimuthal , Wenner-Lee arrays for determining the strike of predominant joint sets . The results of the field studies include the following : in a formation having a predominant , vertical joint set , the maximum value of the apparent resistivity ( pa ) occurs in the same direction ( azimuth ) as the joint strike ; the polar coordinate graph of pa for such a formation is approximately elliptical ; the coefficient of anisotropy ( ^ ) can be calculated from the field data , and values of λ for jointed formations are in the same range of values reported for layered formations ; values of λ are higher at mined sites than at unmined sites . The azimuthal resistivity method and horizontal profiling were used at a site in Pennsylvania to delineate a zone of intensely jointed and fractured bedrock that provided a flow path from a surface stream to a mine . Analysis of the data has been based on a simple model of a jointed formation having a single joint set ; the success achieved to date indicates the need for a more complex model and additional field data .

Jan 1, 1983