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By C. H. Schack

Extractive metallurgy techniques currently employed to recover silver from primary ores and secondary scrap were reviewed and evaluated to identify and delineate metallurgical problems whose resolution would increase the supply of silver from domestic materials. The survey revealed that practically all primary silver is recovered by froth flotation concentration of various types of ores, followed by smelting and refining of the separate lead, copper, and zinc concentrates. Silver losses during the complex processing are, with rare exception, inconsequential. Furthermore, any silver production gain from base metal ores, which contribute about two-thirds of the total primary silver, is directly dependent no improvement in the market for the base metals. Statistical data on new and old silver scrap are wholly inadequate to make reliable conclusions about scrap processing problems and the possibility of increasing the recovery of silver from the many forms of secondary silver-bearing materials. The available information indicates (1) that efficient silver reclamation practices are employed by the larger users of silver, and (2) that recovery of additional secondary silver involves solution of problems of collection rather than of processing. Several possibilities exist for limited increases in silver production from primary ores by improvement in metallurgical practices. Specifically, research is needed to (1) solve the problem of recovering silver from the copper ores of the Copper Range district, Michigan; and (2) devise economically feasible methods for recovery of silver from presently marginal or submarginal ores char because of grade, location, and frequently complex nature cannot presently be exploited by conventional techniques.

Jan 1, 1965

The mineral Industry, following the economy as a whole, experienced little growth in 1992. However, with modernized plants, efficient workforces, and lower operating costs, the industry is well positioned to take advantage of possible improvement in the national economy during 1993. In addition to the significant 1992 events highlighted below, important events, trends, and issues within individual mineral industries are addressed in the commodity sections that follow. The value of processed materials of mineral origin is estimated to have been about $310 billion in 1992. The value of U.S. raw nonfuel minerals production in 1992 is estimated at approximately $32 billion, a 3% increase over 1991. The value of domestic minerals production has increased in all but 4 of the last 32 years.

Jan 1, 1993

Jan 1, 1882

Most of the Indian coking coals are medium coking and of very high ash content. Beneficiation of these coals is a must for their utilisation in coke making. During washing while the ash content of the coal is reduced, the same is expected to affect the reactive-inert ratio and the proportion of various petrographic constituents in the clean coal. This will affect the coking behaviour, including the expansion characteristics, of such coal. An increase in expansion behaviour of coal increases the wall pressure and may damage the battery wall. Therefore, close monitoring of coking properties along with drop in ash is necessary for smooth use of the coal in coke ovens. An effort is, therefore, essential to understand the impact of washing on its coking properties. The studies were carried out with captive coals of Tata Steel, India. Three medium coking coal samples namely, VII A, VI A and XI SEB seam coals of West Bokaro Colliery were used for the study. The coal samples after washing to different ash levels were subjected to the following analysis: proximate, crucible swelling number (CSN), LT GK test, dilatometer and plastometer tests and petrography. The experimental data were then analysed to assess the relationship of various coking properties of the coal with its ash content. The studies clearly show that there is a strong impact of beneficiation of the coal on its coking behaviour. The impacts are more at lower level of ash in the clean coal. In general, the coking properties increase with a decrease in ash. This is primarily due to an enrichment of vitrinte materials in the clean coal and an increase in the reactive-inert ratio in the coals. However, the most important impact of the lowering ash is on the increase in the swelling nature of the coal. The coals with lower ash become highly expanding in nature. This may be very critical from operations of coke ovens point of view, especially stamp charged coke ovens. Necessary precaution should be taken in selecting the other coal blend constituents when these coals are beneficiated to a very low level of ash content.

Jan 1, 2014

By H. Foster Bain

I. INTRODUCTION. By H. FOSTER BAIN.+ THE recently aroused public interest in the conservation of our natural resources has peculiar importance to mining-men, since they deal with resources which are stored products. Within certain limits, the fertility of a worn-out soil may be restored, deforested areas can be replanted, one year's wasted water-supply is followed by another; but coal and ores, once taken out, cannot be mined again, and should therefore be conserved with especial care. This means, however, not that mining should be restricted, but that it should be done most economically and with the minimum of waste.

Nov 1, 1908

By Jack L. Henry

The ternary system A14C3-AIN-Al203 has been examined to determine compositions which may display desirable high-temperature refractory properties. Powder methods were employed in the synthesis of all test compositions. Forming and sintering behavior was examined and hot-pressing parameters were measured. Several properties were studied for each composition of interest in the system. The properties included hydrolysis rate in moist air, elevated temperature oxidation rate, density, softening point, tensile strength, and rupture strength. In most cases equilibrium was not achieved, and the data are representative of a nonequilibrium system. Approximately 16 separate phases have been observed in the system. Forming behavior and selected properties of five compositions of interest were compared with those of aluminum oxide and aluminum nitride. None of the compositions compared favorably. Oxidation and vaporization appear to be serious drawbacks to the use of these compositions at elevated temperatures.

Jan 1, 1969

By David J. Hoadley

This report describes the development and limited testing of a semi-automatic, raise climber, Compact Service Hoist System designed for stope access in underground metal and nonmetal mines. Demonstrated capabilities of the system include a 1,000-lb payload capacity, control from the traveling cage and from up to three remote stations, operating in vertical or inclined raises 3 ft in diameter and up to 300 ft in length and a travel speed of 50 ft/min. The system has the capability of operating in crooked raises because the conveyance climbs two stationary wire ropes suspended down the raise. The drive unit is electrically powered with power and control signals supplied to the drive unit through an umbilical 'cable also suspended down the raise. The system has been designed for portability, ease of installation and minimum raise development. The hoist has been demonstrated successfully in an above ground test tower. This report provides a detailed description of the hoist design and its demonstrated performance to date.

Jan 1, 1985

LOCAL COMMITTEE OF ARRANGEMENTS. Major J. W. Powell, Chairman; F. P. Dewey. Secretary; S. F. Emmons, A. S. Hewitt, J. P- Hilgard, Charles Knap, and F. W. Taylor. THE opening session was held in the hall of the new National Museum, on Tuesday evening, February 21st. President Metcalf introduced General W. T. Sherman, one of the Regents of the Smithsonian Institution, who read the following address: ADDRESS OF GENERAL SHERMAN. MR. PRESIDENT AND GENTLEMEN : I have been invited to meet you here this evening to extend to you the cordial greeting of the regents of the Smithsonian Institution, and to assure you that they are most happy to have it in their power to place at your disposal this beautiful hall, dedicated to science and art. This National Museum is the property of the United States, of which the regents of the Smithsonian are simply the custodians, and the board has delegated to its secretary, Professor Baird, the right to extend its use to the National Academy of Sciences and like kindred societies, among which we are glad to class the Institute of Mining Engineers. It is eminently fit that you should meet here at this, the nation's capital, under a roof partly your own, devoted to natural sciences, and in the shadow of the Smithsonian, founded for the exclusive purpose of collecting and diffusing knowledge among men. Of all the workers employed on earth no single class seem to me more worthy the respect of their fellows than those who seek beneath the surface for the useful minerals and metals which contribute so largely to the wealth and comfort of mankind. In no branch of human industry does intelligence come so immediately in contact with labor. To the mining engineer chemistry, mineralogy, and geology are as reading, writing, and arithmetic to the merchant;

Jan 1, 1882

By T. Lane Carter

(Canal Zone Meeting , October , 1910.) INTRODUCTION. IT is a curious fact that while in our Transactions there are papers dealing with mining-districts in all parts of the world, in Europe, Asia, Africa, and Australia, there is not one which describes the mining possibilities of Nicaragua; our near neighbor. To be most interested in distant objects, like the moon, .and to neglect what lies at our feet, appears to be a trait of human nature. The neglect of Nicaragua is not confined to the American Institute of Mining Engineers. In no other transactions am I :able to find papers dealing with mining in Nicaragua, some parts of which are as much in need of discovery and research as the North Pole.. I hope this paper will be the precursor of many others to be printed in our Transactions, dealing not only with the mining possibilities of Nicaragua, but with the whole of Central America, where there are vast areas awaiting skill and capital for their development. Much of this capital and skill should come from the United States in the future, although it is probable that European capitalists, when they appreciate fully the possibilities, will investigate more and more the mining-resources of Nicaragua and other Central American republics. Fig. 1 is a sketch-map of Nicaragua showing the principal mining-districts. II. HISTORY. Mining in Nicaragua did not begin yesterday. It was commenced by civilized man when the Spanish conquerors penetrated into the interior and forced the natives to procure the precious metal for them. It is strange that the Spaniards did not find more gold, and work on a scale as extensive as in Colombia and other parts of South America. Probably in Nicaragua the Indians covered up most of the rich prospects

Dec 1, 1910

By D. Robert Weir, M. J. H. Ruscoe, R. M. Berezowsky, M. A. Clegg

The metallurgical processing involved in the produc-tion of the new Canadian one dollar coin is reviewed starting with the hydrometallurgical production of pure nickel powder, followed by the powder metallurgy process for the production of nickel strip and coinage blanks, and concluding with the Aureate bronze electroplating and heat treatment procedure. Coinage requirements are then reviewed with regard to economic, public acceptance, and service requirements. Finally the properties of Aureate nickel coinage are presented in the light of the many and varied coinage requirements, and it is concluded that the new Canadian dollar coin exceeds the requirements admirably.

Jan 1, 1990

By Hazel Lyman Nickel

Daring to try where others had failed, Herbert and Lou Henry Hoover translated from the Latin the principal (and first) textbook on the mining and metallurgical profession, De Re Metallica, 1556, which had been in use for two centuries and then had lain dormant for 350 years in a language unreadable except by a chosen few. Thus the Hoovers enriched the English tongue with a vitally important contribution to history in the fields of mining, metallurgy, and chemistry. To them it was a joint hobby, because they were actively interested in the beginnings of the mining profession in which they had both been trained. Illuminating the years of toil to perfect this translation shone their ideal of service to humanity, since, in the Preface, they refer to their task as "a labour of love", which had to find the moments for its execution in night hours, weekends, and holidays, extending over a period of about five years. And they add: "If the work serves to strengthen the traditions of one of the most important and least recognized of the world's professions, we shall be amply repaid". While a student at Stanford University, during the years of 1891-95, Herbert Hoover had become familiar with a copy of this Latin mineralogy classic, De Re Metallica, a rare book in the private library of Dr. John C. Branner, at that time head of the department of geology and mining. Another Stanford student in geology was also examining and studying the ponderous volume of twelve 'books'. She was Miss Lou Henry, of Monterey, who graduated in 1898, and the following year became Mrs. Herbert Hoover. Interwoven through the tapestry of their life experiences gleamed the silver thread of their interest in this mediaeval Latin textbook. Just nine years lacer, the Hoovers had commenced their translation, while they were in temporary residence in London after the seething years in China under the shadow of the Boxer rebellion.

Jan 1, 1949

By W. L. EGY, GEORGES. RICE, L. M. JONES, J. K. CLEMENT

This report has been prepared, not only for the purpose of recording the results of the first series of coal-dust tests conducted in the experimental mine of the Bureau of Mines, but also to place before the mining public a description of the mine and an account of the objects sought in its establishment. Soon after the organization of the technologic branch of the United States Geological Survey, J. A. Holmes, then chief of the branch, concluded that for the solution of various problems relating to the causes and prevention of mine explosions it would be best to carry on large-scale tests in a mine rather than in a surface gallery. The idea of utilizing the underground passage of a mine for making explosion experiments did not at' first meet with general approval among investigators in this country or abroad. Many thought a mine passage was not a proper place in which scientific tests could be conducted, as great difficulty in controlling conditions was expected. However, after all arguments for and against such an investigation had been carefully considered, plans for opening an experimental mine were definitely adopted by the Bureau of Mines in 1910, and an allotment of funds was made to carry out the project. The first endeavor was to find an existing mine suitable for the purpose, but the mines offered by owners were either worked out, were wet, had poor roofs, or presented complications of various kinds, so that it was finally decided to open a mine if a site could be obtained having natural conditions that would fill the various requirements. A most desirable location was found on property of the Pittsburgh Coal Co., near Bruceton, Pa. The president of this company, Mr. W. K. Field, the general manager, Mr. G. W. Schluederberg, and the chief engineer, Mr. E. J. Taylor, rendered every possible service in

Jan 1, 1913

Several primary ingot producers have introduced price changes for July. Howmet Aluminum Corp., Revere Copper and Brass, Inc. and the Anaconda Co, will increase late-July prices of 99.5 percent unalloyed aluminum ingot by 3 cents to 56 cents per pound, Prior to this, Kaiser Aluminum and Chemical Corp. had advanced June ingot values by 4 cents to 57 cents and Consolidated Aluminum Corp., 4.5 cents to 57.5 cents. Domestic merchants held June quotes at a range nearing 50-50.8 cents per pound. ANTIMONY Although NL Industries, since April of this year, stopped publishing prices for RMM and Lone Star antimony grade, values of domestically-refined antimony in alloy are being made available to industry, The current price of this material is $1.75 per pound of antimony contained in alloy, New York dealer-marketed metal was available in June at $1 -13-$1 .20 per pound. Important industrial uses of antimony are for flame retardants, storage batteries, chemicals, pigments, rubber, plastics, glass, ceramics and machinery.

Jan 1, 1978

By W. F. RITTMAN, E. W. Dean

This report presents the results of an investigation conducted by the Bureau of Mines for the purpose of assisting in the establishment of a satisfactory standard method for the analytical distillation of petroleum, a problem of great importance to the petroleum industry. Experiments were performed for the purpose of studying the charac- teristics of methods typical of those in use; comparative studies were made of the efficiencies of the principal types of fractionation ap- paratus available to the petroleum chemist; and the characteristics of a type of apparatus that the results of the experiments seemed to indicate was best adapted to the purpose were investigated in detail. Also, some experiments were made to determine the effect of cracking as a factor in the analytical distillation of petroleum in still heads.

Jan 1, 1916

By Alan K. Burton

Massive increases in the productive capability of open pit nines after World. War II were in a large part made possible by the introduction of ever larger trucks and the supply of a seemingly bottomless ocean of inexpensive and readily accessible oil. Over a period of about 25 years, a variety of technological developments permitted a tenfold truck payload increase, from about 32 tonnes (35 tons) to 320 tonnes (350 tons). There is no, doubt that this was a remarkable achievement resulting in impressive benefits of scale as well as the ability to control what would otherwise have become an intolerable traffic congestion problem in today's large open pit mines. It became fashionable and economically possible during this time to mine large quantities of low grade material and to tolerate very high stripping ratios. As tine has gone by and as easier to get at and higher grade deposits have been depleted, ore grades have tended to decline while stripping ratios have increased. The alternative to reduced revenues has been an ever increasing demand to step up production which in turn has led to a continuing demand for ever larger and larger trucks. While a larger truck has had the effect of reducing the cost of the operator per unit of material moved and of reducing traffic congestion, it has not specifically addressed the subject of fuel cost.

Jan 1, 1981

By C. H. Schack

Extractive metallurgy techniques currently employed to recover silver from primary ores and secondary scrap were reviewed and evaluated to identify and delineate metallurgical problems whose resolution would increase the supply of silver from domestic materials. The survey revealed that practically all primary silver is recovered by froth flotation concentration of various types of ores, followed by smelting and refining of the separate lead, copper, and zinc concentrates. Silver losses during the complex processing are, with rare exception, inconsequential. Furthermore, any silver production gain from base metal ores, which contribute about two-thirds of the total primary silver, is directly dependent in improvement in the market for the base metals. Statistical data on new and old silver scrap are wholly inadequate to make reliable conclusions about scrap processing problems and the possibility of increasing the recovery of silver from the many forms of secondary silver- bearing materials. The available information indicates (1) that efficient silver reclamation practices are employed by the larger users of silver, and (2) that recovery of additional secondary silver involves solution of problems of collection rather than of processing. Several possibilities exist for limited increases in silver production from primary ores by improvement in metallurgical practices. Specifically, research is needed to (1) solve the problem of recovering silver from the copper ores of the Copper Range district, Michigan; and (2) devise economically feasible methods for recovery of silver from presently marginal or submarginal ores that because of grade, location, and frequently complex nature cannot presently be exploited by conventional techniques.

Jan 1, 1965

By G. M. Carr-Harris

"THE SUBJECT of permanent molding has received a great deal of attention in the technical press as illustrated by the many excellent articles in the bibliography which follows. In general, this covers the period 1940-1958 and is merely representative of what is available. Numbers in •brackets refer to items in the bibliography.It may be desirable at the outset to give a few definitions covering those terms directly related to this subject. The following is a definition of permanent-mold casting as given by J. W. Meier in a paper, ""The Non-Ferrous Metals and Alloys"", read before the Ottawa Valley Chapt.er of the American Society for Metals:""Permanent Mold Casting is used where a large number of castings of the same part are required and higher mechanical properties, greater density and closer tolerances are essential. Since metallic mold s are very expensive, the number of castings must be sufficient to, defray, at least partially, the added expense. Molds are usually made from a good quality cast iron, 1but other mold materials, such as the aluminum and copper alloys, graphite, ceramics, etc., are being used in certain cases. Important factors in permanent mold casting are the mold temperature; the proper mold dressing; and, as in all other casting methods, the mold geometry, that is to say, the design of spruces, gates, risers and vents""."

Jan 1, 1960

By William R. Hardwick

Present information indicates that a copper deposit can be safely fractured with a nuclear explosive and the copper successfully recovered by the in-situ leaching method. The process is not yet at the stage where it can be presented t ) the mining industry as a technique proven in all its aspects, but it is a method with high success potential. Unknown factors must be evaluated by a full-scale test before the economics or the extent of the use of the method by the mining industry can be predicted. Preliminary calculations indicate that the cost of fracturing a copper deposit nuclear explosives may range from l.8 to 55.2 cents per ton or in some case: less than a cent per pound of recoverable copper. Copper may be recovered at less cost than by conventional methods. Deposits with 4 pounds of recoverable copper may be economic and production from a deposit may begin in less than half the time required for conventional methods.

Jan 1, 1967

By BRETTMANN TRACY

Jan 1, 2000

By D. Harrington

Dust diseases are much before the public at present, but little reliable information on the subject is readily available to the layman; even those rated as experts usually have a more or less theoretical conception of these diseases, their causes, remedies, and prevention. Until recently little attention has been given to prevention, and the usual attitude of the engineer, upon whom the main reliance for prevention ultimately must devolve, has been to let "sleeping dogs lie" or, more definitely, to "let well enough alone." However, the "laissez faire" attitude no longer is tenable; in the past few years numerous conditions have caused those engaged in industry, including mining, to study the subject with a view to ascertaining the facts upon which to formulate remedial measures, primarily preventive. This bulletin is an attempt to assemble information in convenient form on effects of breathing dusts, largely in the mining and allied industries. The literature on this subject is so extensive that no attempt has been made to include all published material or all types of dust diseases but only to assemble some of the more outstanding data on several aspects of the subject, especially with reference to silicosis.

Jan 1, 1937