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By W. L. Crentz

Before Korea was partitioned along the 38th parallel following World War II, the coal fields of South Korea, with the possible exception of the Samchok area, were not considered important to the industrial needs or Japan or Korea. Much of the demand for electric power in South Korea was met by hydroelectric installations north of the 38th parallel. Following cessation of hostilities between Japan and the' Allied nations in 1945, hydroelectric power continued to flow into South Korea from the north until 1949, when the North Koreans severed the power lines into South Korea, thereby forcing that section of the country to depend almost entirely upon coal to generate electric power.

Jan 1, 1953

By W. W. Adams

"A recent paper prepared by the writer summarized the results of an analysis of the accident records of 34 metal mines for the calendar year 1925. The present paper summarizes the results of a similar analysis of the accident records of 59 coal mines for the same year. This summary is based upon reports furnished to the Bureau of Mines, Department of Commerce, by operating companies that par¬ticipated in the National Safety Competition of 1925.The purpose of the Competition was to establish the lowest accident-severity rate, thus showing the smallest loss of time from accidents in proportion to total number of man-hours worked. The reports covered all lost-time accidents that occurred during the year, that is, all accidents that disabled an employee beyond the day or shift on which the accident occurred. Detailed information for each of the 59 coal mines is given in the appended table. Each mine employed at least fifty men underground; over half of than employed more than 200 men underground. Hence the accident records should be typical of those of large-scale mining operations in general where the company is devoting special attention to accident-prevention work. The mines covered by the reports are situated in eleven States: Alabama, Illinois, Indiana, Kentucky, Maryland, Ohio, Pennsylvania, Tennessee, Utah, Washington, and West Virginia.A tabulation of the reports covering the 59 mines showed an accident-frequency rate of 123 per million hours of ""exposure* and an accident-severity rate of 10.214 per thousand hours of exposure3. The total volume of exposure or employment was 29,117,561 hours, representing the equivalent of work of 12,000 men for three hundred 8-hour shifts. The records covered employment and accident above ground as well as underground, although they did not include stripping or open-pit mining. Accidents during the year resulted in 33 deaths, 1 permanent total disability, 28 permanent partial disabilities, and 3,510 temporary injuries. These accidents represented a loss of tine equal to 297,417 man days. In arriving at this lost-time equivalent, each fatality and permanent total disability was weighted at 6,000 lost days (see footnote 3), as specified in the scale adopted by the International Association of Industrial Accident Boards and Commissions; permanent partial disabilities were weighted according to nature of injury, in accordance with the scale adopted by the :Board; temporary injuries were weighted according to the actual number of calendar days during which the employee was incapacitated as a result of the injury."

Nov 1, 1926

By A. Soderberg

This paper describing the mining practice at the Utah Copper Co., Bingham Canyon, Utah, is one of a series being prepared by the Bureau of Mines on mining practices, methods, and costs in the various mining districts of the United States. The Utah Copper Co. operates the low-grade open-out copper mine at Bingham Canyon, Utah, which is 30 miles in a southwesterly direction from Salt Lake City. In addition to the mine the company operates two flotation concentrators, the Magma plant and the Arthur plant, which have a combined capacity at maximum metallurgical efficiency of 60,000 tons daily. The concentrators are at Magna, about 18 miles from the mine. The company operates its own standard-gage railway, known as the Bingham and Garfield Railway, between the mine and the mills (fig. 1). Concentrates are smelted at the Garfield smelter of the American Smelting and Refining Co., situated 4 miles from the mills.

Jan 1, 1930

By Dayton C. Bolin

This paper is one of a series being prepared by the United States Bureau of Mines describing quarrying methods and costs at stone quarries throughout the United States. These papers are designed to disseminate technical information regarding the methods used. The cost tabulations represent operating expenditures only and not total production costs. It is recognized that publication of total production costs might in many instances cause embarrassment to individual producers as well as to the industry as a whole. On the other hand, operating costs are essential to the technical discussion and study of the methods employed. The attention of the reader is specifically called to this differentiation in order that no misunderstanding of the scrope of the cost tabulations shall ensue. ACKNOWLEDGMENT The author wishes to acknowledge the assistance of J. R. Thoenen, mining engineer, United States Bureau of Mines, in the preparation of this paper. Acknowledgment is also made to E. R. Lederer, vice president in charge of the company's operations, through whose kindness the preparation of this paper was made possible. E. T. Eubank, superintendent of the quarry, and J. A. Hodges, quarry foremen, gave much of their time to this work. The cost data were compiled by the company's chief clerk, J. von Carlowitz.

Jan 1, 1931

By A. W. Fahrenwald

"About two years ago the Bureau of Mines, Department of the Interior, and the University of Idaho undertook an investigation of classification in its relation to table concentration of Idaho ores. The cooperation of the management of the Bunker Hill & Sullivan Co. in placing at our disposal their West Mill and facilities as desired, offered an unusual opportunity for studying the field of hindered classification in its practical and economic relation to table concentration.It has been shorn theoretically, and demonstrated experimentally, that ore products are more easily and economically concentrated on tables if the natural feed, consisting of various minerals and of all sizes of particles of each mineral, be classified or grouped into a series of products in which the mineral particles of greatest density are small in diameter relative to the diameter of the mineral particles of lesser density. Products in which the maximum difference in diameter of light and heavy minerals occurs are to be obtained only by true hindered settling classification. To our knowledge there has never been a really good hindered settling classifier used in practice and the present tendency seems to be to by-pass any attempt at such classification.After a careful study of the nature of hindered classification and of the requirements for hindered settling in practice, a classifier has been developed that takes fullest practical advantage of the widely known, but generally only meagerly understood, condition of hindered settling so well analyzed a number of years ago by Dr. Richards.The present paper presents briefly some of the more important practical results accruing through the investigation."

Jun 1, 1924

By D. L. Sawyer

The Bureau of Mines studied alumina extraction from uncalcined, kao-linitic clay at temperatures from 1000 to 2500 C using 20-or 27-wt-pct-HCI concentrations and with an acid-to-clay ratio of from 0.8 to 1.4 times stoichiometric. Autogenous digestion pressures ranged from atmospheric pressure to about 900 psia. Extraction of 96 pct of the alumina was obtained by HCI leaching at temperatures and leaching times that varied from 1000 C for 120 h to 2000 C for 15 min. Hydrochloric acid stoichiometry of the reaction A1203'2Si02'2H20 + 6HCI + 2AICl3 + 2Si02 + 5H20 was studied at different temperatures and leaching times in a 750-mL tetrafluoroethylene-polymer-lined autoclave. A combination of high temperature and 20 wt pct excess HCI promoted rapid and almost quantitative extraction of alumina (99 pct in some tests). Additional Bureau data obtained with 35-mL tantalum bombs and leach-ing tests with added fluoride are also provided. At high temperatures, the addition of fluoride did not result in a significant improvement over HCI alone and was deleterious to the filtering properties of the digest residue.

Jan 1, 1985

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

By D. Harrington

Approximately 6,000 coal mines are operated in the United States. All of them have in some degree the elements that are likely to contribute to an explosion, hence it is surprising that explosion disasters are not more frequent and that many mines have been operated for years and finally worked out and abandoned without experiencing an explosion. The absence of coal-mine explosions does not always indicate that effective efforts have been made to prevent them but rather that the nine has been fortunate in that the combination of circumstances necessary to cause an explosion has not existed. In view of present knowledge of the methods of preventing explosions, disasters are inexcusable and discredit the mining industry. The methods of preventing mine explosions are known to experienced, well-informed persons engaged in coal mining, yet despite this knowledge far to many coal-mine operators continue to use practices and methods that they should know have resulted in numerous explosions. Moreover, many mine workers persist in following past procedure irrespective of consequences and in breaking safety rules or indulging in practices almost certain eventually to result in disaster. Continued failure to apply known common-sense methods of accident and explosion prevention unquestionably will cell for ultimate enforcement of law.

Jan 1, 1940

By Graham W. Marks

This report is the fourth of a series concerning the development of spectrochemical methods for the analysis of ore samples and related Metallurgical materials by the total-energy method. In this report, the application of this method to the determination of thallium is discussed. This element lies in group III of the periodic tale; one other Clement of this group; indium, has already been investigated.

Jan 1, 1949

Alabama ranked 19th in the Nation in nonfuel mineral value1 in 1994, down from 18th in 1993, according to the U.S. Bureau of Mines. The estimated value for 1994 was $576 million, a 2.5% increase over that of 1993. This followed a 3.5% increase in 1993 over that of 1992. The State accounted for a little less than 2% of the U.S. total. Nonfuel mineral production in Alabama consisted entirely of industrial minerals; no metals were mined in the State. Bauxite materials mined in the State are a natural mixture of bauxitic clay and bauxite having very low iron oxide content and are primarily used to make refractory (high temperature resistant) products, rather than in the production of primary aluminum. In descending order of dollar value, the top four mineral commodities produced in Alabama were crushed stone, portland cement, lime, and construction sand and gravel. These commodities accounted for almost 88 % of the State's total non fuel mineral value, while crushed stone and portland cement together represented almost 65 % of the total. In estimated mineral production for 1994, Alabama remained first in common clays and first of only two States that produced bauxite; third in lime, kaolin clays, and fire clays; seventh in portland cement and salt; and was one of the top seven States that produce bentonite clays. The State dropped from third to fifth in masonry cement. Production of talc and pyrophyllite resumed in 1994. Compared with 1993, the value of crushed stone, lime, construction sand and gravel, common clays, kaolin clays, fire clays, bauxite, and talc and pyrophyllite increased. Decreases occurred in portland cement, masonry cement, industrial sand and gravel, and dimension stone.

Jan 1, 1995

By H. C. Hamontre

[The Bureau of Mines well-bore caliper was designed to provide an instrument that could be operated through 2-inch tubing, which 'a used particularly in many input wells on water-flooding projects of eastern, Kansas and northeastern Oklahoma. It should find wide application elsewhere under many other conditions where it has not been possible previously to make caliper logs with the larger probes used on other instruments. The caliper has three additional advantages over other instruments of this type: (1) It measures 4 radii (up to 18 inches) 90° apart with an accuracy of ± 1/4 inch; (2) the measuring arms can be opened and closed at will by remote control; and (3) it is run and operated on a single-conductor, armored electric cable (Amergraph, type 1-H-0). The caliper probe is 1-3/4 inches in diameter and approximately 6 feet in length. The electrical control and measuring circuits are encased in a stainless-steel tubular case. Measuring arms, made of 5/16-inch aluminum tubing, are attached near the lower end of the instrument. Distances the arms are extended are indicated t the surface by a meter calibrated to read directly in inches. Depths at which the radii measurements are taken are indicated by a wireline depth indicator on the cable-reeling. The instrument is not affected by pressure or temperature, it can be run open hole or under pressure through a lubricator. This paper describes and illustrates the instrument and outlines the operating procedures. A bibliography at the end of the report gives references to articles and patents on the development and use of other well-bore calipers.]

Jan 1, 1954

By Maria I. De Rosa

The U.S. Bureau of Mines performed experiments to determine the embedded hydrogen chloride (HCI) and smoke particle characteristics during combustion of polyvinyl chloride (PVC) and chlorinated mine materials for development of a test parameter. The experiments were conducted in an approximately 20-L furnace at set furnace temperatures of 250° and 1,000° C, for a 14-min duration, with an airflow through the furnace of 10 L/min. The variables studied, as a function of time, were hydrogen chloride embedded on smoke particles, hydrogen chloride concentrations in the gas phase, smoke particle average diameter (dg) and particle concentration (no), and product of smoke particle diameter and concentration (dgno). Other variables included carbon monoxide (CO), carbon dioxide (CO2), and oxygen (O2) concentrations; sample mass weight loss; and furnace temperatures. Results show that there is a correlation between embedded hydrogen chloride, hydrogen chloride gas concentrations, and inverse of the smoke particle diameter-concentration product (1/dgno); the higher the hydrogen chloride gas concentrations, the higher the embedded hydrogen chloride, the higher the 1/(dgno) values. These correlations will enable development of a simple test parameter to assess the toxic hazard that these materials pose during fire.

Jan 1, 2010

By G. H. Keith

The Bureau of Mines determined the mechanism(s) involved in observed anomalous changes in mechanical properties of vanadium-base alloys. Tensile properties of electrorefined and commercial-purity vanadium-base alloys containing up to 5 atomic percent molybdenum or titanium were measured between 77° and 673° K. Snoek oxygen and nitrogen peak heights were measured to determine the changes in dissolved interstitial content caused by increasing quantities of solute. In addition, changes in lattice parameter were followed wit: precision X-ray techniques. Softening, observed in alloys containing titanium, is explained by the formation of a second-phase titanium compound with oxygen or nitrogen. However, because of partitioning of titanium between compound formation and solid solution formation, about five times the stoichiometric amount was required for complete reaction. Addition of 1 percent titanium drastically lowered the strengthening due to strain aging, at 673° K, and 2 percent titanium essentially eliminated it. All alloys were ductile at 77° K. Variations in the tensile properties of the molybdenum-containing alloys are explained by variations in the amounts of interstitial impurities present. The molybdenum did not react with these impurities and had no effect on strengthening due to strain aging. Commercial-purity vanadium alloys containing more than 2 percent molybdenum were brittle at 77° K.

Jan 1, 1969

By Mary S. Esfandiary

This is a revision of a directory of coal research organizations throughout the world that was first published in 1961 as Bureau of Mines Information Circular 8008. Because of the wide acceptance of the first edition, a revision which would supply up-to-date information on coal research and which would facilitate communication among organizations of similar interest seemed important. This compilation includes the names and activities of organizations of various types-government, university, private, and industry. The areas of investigation that each organization is engaged in are indicated in broad terms: Analysis and constitution, mining and geology, preparation, briquetting, combustion, high- and low-temperature carbonization, gasification, conversion to solid and liquid fuels, and health and safety. Publications issued by and describing the work of each organization are cited; almost all of the organizations also publish results of their investigations in the technical press. Selected technical and trade publications that publish information on the science and technology of coal and are not published directly by any of the organizations listed are cited in the pages following the list of organizations in each country.

Jan 1, 1966

By John B. Bennett

In this report estimates are presented of the impact of the passage of five recently proposed "acid rain" bills on electric utility costs for coal-burning utilities servicing the domestic aluminum smelting industry, and on the costs of production for affected aluminum smelters. As aluminum smelting is an energy-intensive industry, domestic increases in electricity prices could affect the industry's competitiveness. Energy costs in U.S. aluminum smelting are compared to aluminum smelting energy costs in the rest-of-the-world. Governmental policies affecting these energy costs are discussed.

Jan 1, 1988

By James H. Gary

Data regarding the composition and physical properties of Florida land-pebble phosphate-waste slime are presented, and the feasibility of dewatering and beneficiating the slime by several different methods is discussed. Chemical analyses, electron micrographs, and X-ray diffraction data showed that principal constituents of the slime included quartz, attapulgite, and flaorapatite. Viscosity of the slime changed with pH; thixotropic, Newtonian, and rheopectic states were observed as the pH increased. Use of various flocculating agents was not effective in improving thickening properties of the slime. Dewatering tests using pressure filtration showed that temperature influenced the filtration rate more than pressure; the filtration rate at 165° C was tenfold that at room temperature. Selective flotation of the slime, using two different processes, gave promising results. About 25 pct of the phosphate was recovered in a concentrate assaying 31 pct P205, Other tests demonstrated that the slime could be successfully fractionated at 20-microns using a hydrocyclone. In hydrometallurgical tests about 80 pct of the phosphorus and alumina were chemically extracted from the slime using sulfuric acid. Limited bacteriological studies made of the slime showed that several types of microorganisms were present and grew in the material despite the presence of fluorine-bearing minerals.

Jan 1, 1963

By A. B. Needham

Graphite is a raw .material of considerable importance in both waxy and peace. Two types of graphite, classified according to particle size as flake and fines, are used, but the former is in much greater demand. The principal wartime use of graphite is in the manufacture of crucibles for melting brass and special alloys of copper and steel. Other uses in both peace and war are as lubricants, for foundry facings, and in paints, electrodes, batteries, motor and generator brushes, and a variety of other commodities. . This paper describes the operations of the Southwestern Graphite Co. of Los Angeles, Calif., which produces both flake and fine graphite from a property in Burnet County, Tex.

Jan 1, 1946

By Larry A. Haas

A major problem encountered in dump leaching operations is the plugging of both the dump and the piping by precipitated iron compounds. Bureau of Mines research to obtain basic data on agitation leaching and dump leaching methods has shown that the addition of organic chelating reagents can significantly enhance the lixiviant permeability through the ore and the concentration of the metal values in the liquor. For example, the addition of 5 giL citric acid (CA) to a conventional sulfuric acid lixiviant almost doubled the fluid flow rate through 5-cm-diameter laboratory columns containing copper ore. After 185 h of per-colation leaching, the metal concentrations with (and without, in parentheses) CA were 1.7 (1.5) giL Cu, 200 (70) ppm Mn, 160 (40) ppm AI, and 6 (3) ppm Co. The enhancement of metal concentrations with chelating reagents such as CA was confirmed by determining the solubil-ity of several metal ions as functions of pH and chelating reagent con-centration. When ferric ions became insoluble at pH values above 3, the concentrations of other ions also decreased. The addition of che-lating reagents kept iron, as well as the other dissolved metals, in solution even at pH values as high as 5. Citric acid was a more effective chelating reagent than gluconic acid, oxalic acid, or sodium lignin sulfonate.

Jan 1, 1985

By Mary S. Esfandiary

This is a revision of a directory of coal research organizations throughout the world that was first published in 1961 as Bureau of Mines Information Circular 8008. Because of the wide acceptance of the first edition, a revision which would supply up-to-date information on coal research and which would facilitate communication among organizations of similar interest seemed important. This compilation includes the names and activities of organizations of various types-government, university, private, and industry. The areas of investigation that each organization is engaged in are indicated in broad terms: Analysis and constitution, mining and geology, preparation, briquetting, combustion, high-and low-temperature carbonization, gasification, conversion to solid and liquid fuels, and health and safety. Publications issued by and describing the work of each organization are cited; almost all of the organizations also publish results of their investigations in the technical press. Selected technical and trade publications that publish information on the science and technology of coal and are not published directly by any of the organizations listed are cited in the pages following the list of organizations in each country. Information that would improve coverage and accuracy of the next revision of the publication will be welcomed by the Bureau of Mines.

Jan 1, 1966

By G. S. Scott

[In the course of the investigation the Bureau of Mines is carrying on to determine the causes, behavior, and control of mine fires, the detection of incipient heating underground in the mines and above ground in refuse banks has received consideration. A report has been published5/ describing apparatus and tests made on anthracite to determine the amount and composition of the a oxidation products when normal dry air was passed through it at temperatures varrying from 100° to 350° C. These tests showed that the amount of evolved gases and their relative proportions varied with the temperature. From these results, graphs were prepared by which the temperature at which the coal was oxidized could be estimated thus giving a possible means of detecting incipient heating.]

Jan 1, 1938