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The problem of separating the constituents of a mixed gas has assumed increasing importance to chemical technology during the last several decades. Metallurgical practice, dealing mostly with the application of gases as fuel, such as for the oxidation or reduction of ores, has not often confronted an important need for such separations. If theory occasionally has indicated advantages in the use of purified or separated gases, as for example the "dry" blast for the iron furnace or oxygen-enriched blast for a variety of smelting operations, the economics of the proposals has not often been satisfactory. It has seemed evident that the practice of the chemical plant was too expensive with regard to installation or material costs, or both, for the needs of the basic smelting industries and indeed was applicable commercially to metallurgical purposes only when the metals in question were especially valuable or pure. This bulletin deals with a new mechanical means of attacking the problem of separation. Although it is improbable that any one type of separation could hope to find universal application, the method described is to be regarded as an alternative to conventional means that has attractive possibilities in certain instances. It extends the number of methods previously available by one that has not before been applied commercially and that utilizes a well-known property of gases that never has received effective technologic attention.

Jan 1, 1940

By C. A. Komar

The Bureau of Mines is investigating possible applications of acoustic energy at sonic and ultrasonic frequencies in petroleum production. A phase of this work involves measuring sound velocity through petroleum reservoir rocks. References and abstracts were prepared as a bibliography to make available to others some of the material obtained from a literature search covering the past applications and the present uses of sound. Laboratory and theoretical studies of the various parameters that influence the velocity of sound in porous media account for the wealth of information now available. Velocity of propagation of sound waves in porous sediments as a function of depth is a quantity frequently measured. Velocity logging systems, capable of measuring speed of sound waves in underground formations penetrated by wells, have been developed for interpretative studies. The close relation between acoustic velocity and porosity makes it possible to determine porosity from velocity logs. Most velocity log interpretation in terms of porosity is based on a formula developed by Wyllie and others known as the time-average relation.

Jan 1, 1963

By Daniel E. Sullivan

This Bureau of Mines publication examines the potential impact on minerals of the tariff and nontariff agreements that resulted from the Tokyo Round of the Multilateral Trade Negotiations, which were conducted under the auspices of the General Agreement on Tariffs and Trade. These agreements will affect minerals by reducing tariff levels and by changing rules by which they are traded internationally.

Jan 1, 1981

The first metal-mine accident-prevention course was prepared and published in 1942-45 as a series of seven miners' circulars (Nos. 51-57). The scope of the course has been broadened, revised, and brought up to date, and it is being published as a similar series of seven miners' circulars on accident prevention in metal and nonmetallic mines. These circulars are: 1. Accident Statistics (Miners' Circular 51), dealing with general statistics on accidents and injuries at metal and nonmetallic mines, including causes, costs, and the uses of investigations and reports of all accidents.

Jan 1, 1957

By C. C. Stevenson, Thomas Varley, E. P. Barrett, ROBERT H. BRADFORD

The art of treating ores by the chloride volatilization process is still in the experimental stage. The process has not been sufficiently developed along metallurgical lines to warrant a definite statement as to the exact place it will occupy in the industry. The basic theory of the process has received the attention of prominent metallurgists for 20 years, and considerable research and experimental work have been carried on. Much of the experimental work done has never been published; if the accumulated results were made known, they would greatly aid,. the further development of the process. This bulletin aim~ to bring the salient features of the process to the attention of metallurgists for the purpose of furnishing information to and receiving comments from interested parties with the ultimate hope that the process will be a commercial success. If commercially utilized, the process will fill a long-felt want in metallurgy, especially in the treatment of oxidized and semioxidized or" carbonate" ores of copper, lead, and silver. Such ores are difficult to treat by gravity concentration or by flotation: in the former their tendency to slime upon crushing and their being of lower specific gravity than the sulphide minerals cause serious losses; in the latter much has been done in sulphidizing oxidized ores and subsequently recovering the artificial sulphides by flotation. Difficulties in proper sulphidizing and the low recoveries obtained have not balanced the cost of the treatment in many plants and in very few has it proved successful. Evidently there is a big void to fill in the treatment of these ores. No radical changes in present methods are forecast, but it is obvious that chloride volatilization can have a distinct place as a method of treatment for ores that are not readily amenable to present methods. In many plants it might replace concentration methods, especially where part of the mineral content in the ores exists in forms other than sulphides.

Jan 1, 1923

By Ralph B. Youtz

This paper describing mining methods at, the Eighty-Five mine of the Calumet and Arizona Mining Co., Valedon, N. Mex., is one of a series being prepared by the United States Bureau of Mines on mining methods, practices, and costs in the various mining districts in the United States. The Eighty-Five mine is in southwestern New Mexico, 3 miles southwest of Lordsburg, Hidalgo County (see fig. 1). The mine produces normally 7,000 to 8,000 tons per. month of silicious copper-gold-silver ore, and employs approximately 200 men underground and 40 on-the surface. Mining is done by shrinkage and cut-and-fill methods.

Jan 1, 1931

By Oliver Bowles

The manufacture of lime is one of the oldest industries. Plants are distributed widely and furnish an essential raw material for numerous industries. The use of lime by the building trades, in agriculture, and in hundreds of manufacturing and chemical processes has created demands for a large production and has necessitated exhaustive research on methods of manufacture and uses. The bibliography of lime is an extensive one, but for the most part each publication has dealt with only certain operations. The purpose of this paper is to present a general picture of the industry as a whole. The abundant literature has been abstracted and quoted freely, and the National Lime Association has rendered valuable assistance in furnishing data for certain sections. Publications containing more detailed information on the various branches of the industry are referred to in the footnotes and in the bibliography.

Jan 1, 1936

By J. W. Lyman

The U.S. Bureau of Mines investigated methods of separating valuable rare-earth materials from Fe in neodymium iron boron (NdFeB) magnet scrap. A selective oxidation treatment of the scrap oxidized the rare-earth portion while leaving elemental Fe. Magnetic and leaching procedures were tried for separating the metallic Fe and rare-earth oxides, but the extremely fine grain size of the oxidized scrap prevented recovery by either technique. The best separation of rare earths from bulk NdFeB magnet scrap was obtained by dissolution with H2S04 followed by precipitation of recyclable rare-earth salts. By precipitating neodymium-alkali sulfate double salts as an intermediate that can be converted to a variety of useful products, many materials-handling and economic disadvantages found with direct precipitation with fluoride or oxalate were avoided. Iron was removed from magnet leach solutions by precipitation as a jarosite, eliminating a major disposal problem. Research was also conducted with contaminated mixed SmCo5 and NdFeB swarf. Using a flotation-leaching technique allows the SmCo5 to concentrate in the froth, while the grinding-medium contaminant sinks and is removed as tailing. The NdFeB is dissolved by H2S04 during the process.

Jan 1, 2010

By D. G. Willard

The U.S. Department of Interior, Bureau of Mines has evaluated the potential resource and annual availability of cobalt from 27 deposits or districts in 11 market-economy countries. More than 95 pct of primary cobalt production from market-economy countries, mainly byproduct output from copper and nickel operations, was analyzed. Approximately 1,200,000 mt of cobalt is potentially recoverable at the demonstrated resource level. Very large additional resources exist, especially in laterite deposits, but are at the inferred level. The producing operations evaluated in this study are expected to produce about 19,000 mt of cobalt in 1989, significantly less than the available capacity of about 31,000 mt. More than 14,000 mt per year of cobalt is produced from copper-cobalt deposits in Zaire and Zambia, of which 11,000 mt can be produced at a copper price of $O.60jlb or less with a O-pct discounted cash-flow rate of return (DCFROR). Approximately 4,400 mt of cobalt is produced annually from nickel-cobalt deposits in six countries, of which about 1,800 mt (in Canada and Brazil) could be produced at a nickel price of $1.50jlb or less at a D-pct DCFROR. Approximately 200 mt per year of cobalt is produced from a cobalt mine in Morocco. Most of the evaluated nonproducing operations and prospects that could potentially produce cobalt as a principal product or byproduct would require a total cost (including a 15 pct-DCFROR) significantly exceeding January, 1989 market prices of the principal commodities. Principal-commodity dependence, transportation routes, cobalt toxicity, and other issues that could affect the availability of cobalt are addressed herein.

Jan 1, 1991

By William C. McBee

Specialized sulfur concretes were developed by the Federal Bureau of Mines as a result of research for the beneficial utilization of sulfur in construction materials. Materials were developed for use in acid and salt corrosive environments where portland cement concrete has been found to deteriorate. Because the mineral aggregates also come into contact with the corrosive media, concretes were developed utilizing both limestone and quartz aggregates. The sulfur binder used with both aggregates was modified by reaction with 5 pct dicyclopentadiene to improve product durability. Sulfur quartz aggregate concrete was found to have moderately high strength characteristics (6,000 psi compressive) and was extremely resistant to chemical attack by both acid and salt solutions. Sulfur limestone aggregate concrete exhibited very high strength characteristics (9,000 psi compressive) and was extremely resistant to chemical attack of salt solutions. Both types of concretes maintained their strength and integrity after long-term testing in acid and salt solutions and exhibited considerable resistance to damage by the action of freezing and thawing. Potential uses include leach tanks, electrolytic cells, thickeners, bridge decking, industrial flooring, pipe, and tile.

Jan 1, 1979

1. Domestic Production and Use: In 1982, 13 companies operated 30 primary aluminum reduction plants, with 3 firms accounting for 55% of production. Washington, Oregon, and Montana accounted for 34% of the production; Texas, Louisiana, Missouri, and Arkansas 18%; Tennessee, Alabama, South Carolina, and North Carolina 14%; other central and eastern States 34%. Based on published producer prices, output of primary metal in 1982 was valued at over $5.5 billion. Aluminum consumption by 25,000 firms was centered in the East Central United States. Packaging accounted for an estimated 39% of domestic consumption in 1982, transportation 20%, building 14%, electrical 8%, consumer durables 8%, and other uses 11%.

Jan 1, 1983

By D. R. Tweeton

The U.S. Bureau of Mines, the University of Arizona, Sandia National Laboratories, and Zonge Engineering and Research Organization, Inc., conducted cooperative field tests of six electromagnetic (EM) geophysical methods to compare their effectiveness in locating a brine solution simulating in situ leach solution or a high-conductivity plume of contamination. The brine was approximately 160 m below the surface. The testsite was the University's San Xavier experimental mine near Tucson, AZ. Geo- physical surveys using surface and surface-borehole, time-domain electromagnetic (TEM) induction; surface controlled-source audiofrequency magnetotellurics (CSAMT); surface-borehole, frequency- domain electromagnetic (FEM) induction; crosshole FEM; and surface magnetic field ellipticity were conducted before and during brine injection. The surface TEM data showed a broad decrease in resistivity. CSAMT measurements with the conventional orientation did not detect the brine, but measurements with another orientation indicated some decrease in resistivity. The surface-borehole and crosshole methods located a known fracture and other fracture zones inferred from borehole induction logs. Surface magnetic field ellipticity data showed a broad decrease in resistivity at depth following brine injection.

Jan 1, 2010

By Boyd Guthtrie

[Methods of distilling topped crude oils and distillates under vacuum, accompanied by good fractionation, have taken a place of major importance in the refining industry. In the refining of petroleum products it is generally desirable to produce a distillate of good quality, and this objective is attained by fractionation of a high degree. The laboratory and commercial practice have proved chat by varying the amount of fractionation the quality of the distillate car be changed, and refiners are cognizant of the advantages of good fractionation. Distillation-under high vacuum, however, is a relatively new practice in petroleum refining, and only during the last few years has there boon an indication that that this method ray become a general practice in the industry. Vacuum distillation offers many advantages over older methods of distilling petroleum products. Vacuum combined with steam distillation, for example, is replacing straight-stream distillation because the quality of the products of vacuum and, steam distillation surpasses that of those produced by straight-steam distillation. Although the injection of varying amounts of steam in a vacuum unit is common practice, the amount of steam used is becoming less as the vacuum within the unit is increased. This report describes tie construction of a visible-action laboratory batch still and fractioning; column and. gives curtain data pertaining to the operation of the apparatus under vacuum for the production. of lubricating distillates. The apparatus was designed and built to produce lubricating distillates under as nearly ideal conditions as possible, in order that a subsequent study of the characteristics of the distillates could be made.]

Jan 1, 1932

By George S. Rice

This bulletin traces the growth in the belief in the explosibility of coal dust, summarizes the experiments and mine investigations that have established this belief, and gives the present status of pre- ventive measures. It has been prepared in accordance with the pro- visions of the acts of Congress authorizing investigations relating to the causes of mine explosions, and contains references to and descrip- tions of experiments made at the Federal testing station at Pittsburg, Pa. This station was inaugurated under the United States Geo- logical Survey, and was transferred to the Bureau of Mines on the establishment of the latter on July 1, 1910. Only within comparatively few years has the dry dust of bitumi- nous and lignitic coals been generally recognized as an explosive agent more insidious, threatening, and deadly to the miner than fire damp. Fire damp carries its own flag of warning-the "cap" in the safety lamp-but coal dust, though visible, does not attract attention until present in large quantities. Fire damp is of local occurrence, and except in notable and very exceptional cases is controllable by careful manipulation of ventilating currents. If by mischance a body of fire damp is ignited in a mine, the force of the explosion may be terrific, but the effect is local unless dry coal dust is present, or unless (as it very rarely happens) an explosible mixture of methane gas and air extends through large areas of the mine. In a dry mine dust accu- mulates everywhere, and the blast from the ignition and combustion of bituminous dust may traverse miles of rooms and entries and wreck structures at the entrance to the mine. The comparative potential destructiveness of gas and of bituminous dust is strikingly shown by the history of the Pennsylvania anthracite mines. These mines not infrequently have large inflows of gas, and the resulting mixtures of gas and air have sometimes been ignited, yet no such wide-sweeping explosions have taken place, despite the presence of dry anthracite dust, as have happened in excellently ventilated bituminous mines.

Jan 1, 1911

By Daryl R. Tweeton

The Bureau of Mines is investigating possible applications of geophysics to monitor leachate during in situ mining. Tomographic reconstruc-tion of seismic or electromagnetic crosshole data appears applicable. The tomographic program BOMTOM (Bureau of Mines tomography) was written and then used to investigate reconstructions with synthetic travel time data. The calculations confirmed that without constraints, crosshole data do not provide unique solutions. The solution is not determined solely by the data, but is also influenced by the velocity guesses starting the iterative solution procedure. The effectiveness of constraints in combatting nonuniqueness was examined. The requirement that the velocity not vary laterally at the top and bottom of the pixel grid was effective. This constraint is realistic when the top and bottom of the grid represent dry and saturated re-gions, respectively. Limiting the maximum velocity improved reconstructions, but may not be applicable in practice. BOMTOM uses the simultaneous iterative reconstruction technique (SIRT) with straight ray paths. The program is efficient in use of memory, and can be run on a personal computer. A source code in FORTRAN is listed. A source code in BASICA and compiled executable codes in both languages are available from the Bureau's Twin Cities (MN) Research Center.

Jan 1, 1985

By John G. Parker

Many of the so-called minor metals are derived as byproducts from the processing of lead and zinc concentrates in which they occur as minor constituents. Concentrates from some lead-zinc mineral deposits are more enriched in metals such as cadmium, arsenic, bismuth, silver, and selenium than are others, and these sources offer a continuing, assured supply of certain of these metals. Despite the age of the data collected, the Bureau of Mines feels it to be highly desirable to publish due to its relevance to the objective of the study which was to ascertain the flow of minor metals from certain smelter feeds Efforts to trace these metals through the complicated lead and zinc processing steps included trying to ascertain losses and mode of loss of these metals. Losses of some metals in processing may be surmised as occurring in gaseous and other emissions, or possibly in slags and residues.

Jan 1, 1979

By Paul R. Thomas

The Bureau of Mines evaluated the impact of the depletion allowance upon the economic availability of copper from domestic deposits. The potential long-run percentage depletion deduction, cumulated over the life of the properties, was estimated at approximately $2.5 billion for producing properties and up to $11.7 billion for nonproducers. The income transfer, in the form of higher Federal income tax payments if the allowance were repealed, was estimated at $1.5 billion for producing properties and up to $8 billion for nonproducers. The percentage depletion allowance, through its role in determining Federal income tax liability, was found to be very significant in affecting profitability. Repeal of the allowance could result in major domestic copper availability reductions at all price levels, now and in the future, as a result of reduced profit margins for current producers, and postponement of development decisions for nonproducers. It was demonstrated that a 50-percent reduction in the percentage depletion rate applicable to copper would also result in a significant decrease in profitability for nonproducing properties. For producing properties, the percentage depletion rate on copper was shown to be less significant than the income limitation that is placed upon the total amount of the depletion deduction. Repeal of the minimum Federal tax provision was shown to be significant in enhancing profitability for both producing and nonproducing deposits. The report concludes that the percentage depletion allowance operates as an important method of capital recovery and production incentive.

Jan 1, 1982

By James Westfield

A brief résumé follows of recent activities of the Division of Coal-Mine Inspection that have had a favorable effect on health, safety, and the reduction of injuries at coal mines: 1. The Federal Mine Safety Code for Bituminous Coal and Lignite Mines of the United States was issued originally by the Director of the Bureau of Mines on July 24, 1946, after consulting with management and labor representatives of the coal-mining industry. The code has been used by Federal coal-mine inspectors while inspecting bituminous-coal and lignite mines as a basis for determining the existence of unhealthful and unsafe conditions and practices in these mines. A revised code was issued by the Secretary of the Interior on October 8, 1953, after further consultations with representatives of management and mine workers and was incorporated by reference in the 1952 and subsequent bituminous-coal wage agreements. The agreement of May 29, 1946, between the Secretary of the Interior, acting as Coal Mines Administrator under authority of Executive Order 9728, and the United Mine Workers of America, covering bituminous-coal and lignite mines in Government possession, charged Federal coal-mine inspectors with the responsibility of making periodic investigations of the mines and reporting to the Coal Mines Administrator any violations of the Federal Mine Safety Code. Federal coal-mine inspectors also had temporary authority to close mines found to be imminently dangerous, but such authority (under Executive Order 9728) was removed on June 30, 1947, when Government control of the mines was terminated.

Jan 1, 1958

Lignite constitutes approximately 97 percent of the near-surface coal resources in Texas. The most significant bituminous resources are in the north-central and southern parts of the state. Coal reserves in Texas are estimated to be 13.7 billion tons, about three percent of U.S. coal reserves. The average thickness of coal seams mined in Texas is approximately eight feet. Texas gained primacy when its regulatory program was conditionally approved February 16, 1980; the program was fully approved June 18,1980. The state's Abandoned Mine Lands program was approved June 23,1980.

Jan 1, 1992

By Hillary W. St. Clair

The purpose of this investigation was to determine the practicability of refining crude aluminum-silicon alloy or aluminum scrap containing silicon and iron by selective dissolution in zinc of the aluminum from the alloy followed by distillation of the zinc from the aluminum.

Jan 1, 1949