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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 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

This report, the second in an annual series, summarizes information on latest technological developments and advances, and identifies trends in mining and metallurgy based on a review of activities in the minerals industry in 1971. Exploration and mining data obtained from an annual canvass are presented for 1971 and are compared with similar data obtained over the past decade.

Jan 1, 1973

By Henry C. Meeves

The Bureau of Mines investigated the silver production potential of the Leadville (California) mining district, Lake County, Colo., in 1966-67. The mining history of the district, the ground conditions encountered in mining, and the mine-support methods used are reviewed. The drainage problem is discussed in detail. An initial objective was to establish the existence of potential silver resources minable by low-cost open-pit methods, particularly in the silver-bearing manganese halos surrounding the major deposits. The report concludes that under present conditions, development of the deposits in the area is not economically feasible; however, a pioneer rotary noncore drilling program demonstrated that this type of exploration is technically feasible. Potential reserves of silver and associated metals are estimated. Possible mining methods for recovery of the reserves are discussed. Future production possibilities from the various subareas of the district are analysed, considering optimum operating size. Consolidation of small individual holdings for unit operation is recommended. Type of operation, amount of rehabilitation, size and type of concentrating plants required, drainage and other mining problems, and metal price trends are discussed as they bear on economic feasibility of development.

Jan 1, 1970

This field guide is designed for use in planning pollution control and reclamation activities on small sand and gravel operations. Its purpose is to assist operators in selecting environmentally desirable pollution control and reclamation procedures based upon their particular mining situation. The guide includes information on interpreting physical and cultural factors that must be considered in planning and implementing a mining and reclamation program, achieving environmental protection objectives, and improving community/industry cooperation. Included as appendices are a summary of state laws and a list of additional readings on the subject.

Jan 1, 1981

It is a pleasure to submit to the National Critical Materials Council (Council) some of my thoughts concerning the important tasks which lie before you. It long has been my belief that America's economic health and national security may depend to a substantial degree on whether we have available to us an adequate supply of critical and strategic materials at reasonable cost. To the extent the Council can contribute to the identification and implementation of wise public policies which facilitate the achievement of that goal, we and our children should be grateful. Even before assuming office, President Reagan warned of the danger of undue dependence on imported materials essential to the Nation's defense and economic well-being. After his election, he appointed a transition task force on strategic and critical materials, and he later directed the Cabinet Council on Natural Resources and Environment to prepare .a National Materials and Minerals Program Plan and Report to Congress, which he forwarded to the Congress in April 1982. In 1984, my predecessor, Secretary Clark, established the National Strategic Materials and Minerals Program Advisory Committee, popularly known as the "Mott Committee" because of its distinguished chairman, retired Admiral William C. Mott.

Jan 1, 1986

By Jeffrey A. Shibe

A prototype Fire Safety Evaluation System has been developed and is ready to be evaluated by a Peer Consulting Panel and for performing field tests. The system can be used to determine combinations of widely accepted fire safety equipment and under-ground coal mine features that provide a level of safety equivalent to those required by the Code of Federal Regulations-Title 30 for underground coal mines. In this evaluation, equivalent safety performance is gauged in terms of overall level of safety provided rather than by a component by component comparison.

Jan 1, 1987

By C. C. Popoff

The growth of the aluminum-smelting industry in the Pacific Northwest, resulting from national defense requirements, emphasized a need for local sources of alumina to supplement the alumina production shipped from the East. Because supplies of foreign bauxite were being interrupted and our domestic bauxite reserves were inadequate, it was necessary to expedite the investigation of other possible sources of alumina during World War II. A program of investigation of high-alumina clay deposits in the Northwest was carried out jointly by the Federal Geological Survey and the Federal Bureau of Mines. As part of this program the Cowlitz clay deposits near Castle Rock, Wash., were explored by the Bureau of Mines in 1942-43. These deposits are near railroads, tide-water, and Bonneville Power Administration lines and within 22 to 100 miles of 4 aluminum-reduction plants.

Jan 1, 1955

By J. W. Adams

This report surveys the efforts of six contractors to the U.S. Bureau of Mines with regard to their electromagnetic noise measurement programs. What has been done, what is planned, and evaluations and recommendations are given for each contractor. The main observation is that to date there is not sufficient knowledge of electromagnetic interference in mine environments to design a reliable communication system. This knowledge should be available by the end of June 1972 if certain planned programs are completed successfully. A major effort of this report is to establish parameters to be measured, units to be used, and workable formats for data presentation. This is given in Appendix A. Some details concerning equipment, procedures, locations, and sample data are included in Appendix B.

Jan 1, 1971

By Robert Louis Adams

A general discussion of the structure of the junk automobile recycling system shows that the generation of stripped automobile hulks and scrapped automobiles is price inelastic. As a result, it is extremely difficult for the price mechanism to automatically achieve an equilibrium that will prevent the accumulation of excessive automobile wrecker inventories and vehicle abandonment by the last owners of scrapped cars. The new shredder processing technology and the new portable flattener technology have altered the structure of the junk automobile recycling system. The shredder technology has increased the demand for processed automobile scrap. This increased demand is reflected in higher prices paid for hulks by scrap processors. The portable flattener has reduced the transportation cost of shipping hulks to processors. The two new technologies have eliminated, at least potentially, the net cost of shipping stripped hulks so frequently incurred by wreckers in the past. The elimination of this cost eliminates the economic incentive for excessive wrecker inventories. Unfortunately, the incentive for last owners to abandon their cars does not appear to have been eliminated by the new technologies. The last owner of an automobile with no spare parts value is still likely to incur a cost by delivering his automobile to the recycling system. Although a subsidy payment is probably unnecessary to reduce excessive wrecker inventories, such a payment might be one solution to the problem of automobile abandonment. However, there are a wide variety of subsidy programs that could be introduced. Before any Federal subsidy program is introduced to reduce automobile abandonment, it is recommended that the program be tested on a limited basis in many different parts of the country.

Jan 1, 1973

By Keith Harris

The U.S. economy grew moderately in the second quarter of 1985 with real gross national product (GNP) recording a seasonally adjusted annual growth rate of 2.0%, up from the 0.3% growth of the previous quarter but significantly below the 7.1% growth of the second quarter of 1984 (table I). Personal consumption expenditures grew 5.3%, with purchases of durable and nondurable goods rising 7.4% and 5.1 %, respectively; nonresidential and residential fixed investment--the two components of fixed investment--grew 11.8% and 5.6%, respectively; and Government spending rose 3.6%. However, these gains were tempered by a major decline in the growth of business inventories (from $19.1 billion to $8.3 billion) and the continuing growth of the net export deficit (from -$28.4 billion to -$33.3 billion). While the high value of the dollar compared with other currencies has been a major cause of the expanding trade deficit, its value, as measured by the monthly Federal Reserve Board (FRB) multilateral trade-weighted dollar index, has declined over 17 index points from its February peak to 140.94 in July. The July dollar value was still high historically. The rate of inflation, as measured by the fixed-weighted price index for GNP, remained low at 4.1%, down from 4.3% in the first quarter, and employment continued to grow at a rate sufficient to keep up with new additions to the labor force. Civilian unemployment has remained steady at 7.3% over the past 6 months. Industry Statistics The FRB recently revised its index of industrial production and changed the base year from 1967 to 1977,1/ The revised total index shows a 0.1 % higher annual growth rate between 1967 and 1984 than the previous index. In the slower growing or declining industries, such as metal mining, primary metals, and fabricated metals, however, downward revisions in the indices and rates of growth have occurred. The previous and revised annual rates of growth between 1977 and 1984 for several of the sectors of interest to the mining industry are shown in table 2.

Jan 1, 1985

By Robert H. Peters

Groundfall accidents have been the leading cause of fatalities in the underground coal mining industry for many years. Statistics from the Mine Safety and Health Administration (MSHA) indicate that approximately half of the victims of these fatal accidents were in an area where no devices had been installed to support the mine roof. This report was prepared by the U.S. Bureau of Mines to provide guidance to operators of underground mines concerning the use of techniques that may help to keep miners from going under unsupported mine roof. The report is divided into two major sections. The first section reviews the findings from several areas of empirical research pertaining to strategies for convincing employees to avoid unsafe acts and/or adopt self-protective behaviors. The strategies are (1) incentives and feedback, (2) disciplinary actions, (3) training (primarily fear communications and behavioral modeling), and (4) nondirective techniques. This literature review has a broad focus and should be helpful in making decisions about how to encourage a wide variety of types of self-protective behaviors. The second major section of the report presents an analysis of each strategy's potential for keeping miners away from unsupported roof.

Jan 1, 1991

By E. H. BURROUCHS

This bulletin is the third of the series of yearly petroleum bibliographies being published by the Bureau of Mines. The two preceding, Bulletin 149 and Bulletin 165, were for the years 1915 and 1916, respectively. In arranging the references the same general scheme has been followed, but as in those bulletins, several changes and additions have been made in the classifica.tion, the more important being in the classes " Development and production " and "Refining and refineries." German periodicals for 1917 were not procurable and references to articles in those and in other foreign journals that were not available have been credited to the sources from which they were procured.

Jan 1, 1920

The Technology Transfer Seminar on Mine Communications held on March 21-77, 1973, at the Pittsburgh Mining and Safety Research Center, Bruceton, Pa., presented information about recently developed equipment, instruments, and techniques for use in mine communications systems. All of the basic ideas presented in the fine seminar are operational in the Bureau of Mines Safety Research Mine in Bruceton.

Jan 1, 1974

By Philip C. Tully

[This bibliography contains 3,655 different citations to technical and scienfic literature on helium and alpha-particles, abstracted by 13 abstract service iblicatlons during 1964. Multiple subject classification increases the total number of entries to more than 5,800. Helium citations are listed by 22 major assifications, alpha-particles by 12]

Jan 1, 1970

Despite modest improvements in the performance of domestic interest rates and gross national product,1 fixed investment in domestic producers' durable equipment continued to weaken during the second quarter of 1982 and declined at a 12.8 percent annual rate compared with the first quarter.2 Large declines occurred during the second quarter in expenditures on many of the major mineral-consuming industries such as aircraft, computers, agricultural and construction machinery and mining and oil field equipment. These data appear to be consistent with the low level of business investment plans for 1982 reported in the DOC's Bureau of Economic Analysis survey of expenditures on new plant and equipment.3 Domestic and foreign industrial production and mineral industry production activities continued to decline in the most recent period because of weak demand conditions (Tables 1 and 2). The U.S. mining production index declined 7.7 percent between April and June as compared with 1.2 percent for total U.S. industrial production (Table 1).

Jan 1, 1982

By Frank E. Williams

This Bureau of Mines report describes 147 known fluorspar deposits in New Mexico and briefly mentions 54 miscellaneous occurrences for which little or no information was obtained. Most miscellaneous occurrences are minor and too poorly exposed to be considered more than prospects. History and production of fluorspar in New Mexico, type of deposition, mineralogy, uses, and grade specifications are discussed. Total mine production of fluorspar in New Mexico is nearly 641,000 tons of various grades of crude ore and hand-sorted material. Fluorspar deposits occur in 13 of the State's 32 counties. Grant, Valencia, and Luna Counties account for 86.4 percent of the total production. During the investigation, 141 deposits were visited. A total of 72 character samples was collected for assay, and 3 larger samples were collected for bench-scale metallurgical tests. Results of these metallurgical tests indicate that an acid-grade product can be obtained with 95 percent recovery of the CaF2 content of the crude ore.

Jan 1, 1966

By Frank E. Williams

This Bureau of Mines report describes 147 known fluorspar deposits in New Mexico and briefly mentions 54 miscellaneous occurrences for which little or no information was obtained. Most miscellaneous occurrences are minor and too poorly exposed to be considered more than prospects. History and production of fluorspar in New Mexico, type of deposition, mineralogy, uses, and grade specifications are discussed. Total mine production of fluorspar in New Mexico is nearly 641,000 tons of various grades of crude ore and hand-sorted material. Fluorspar deposits occur in 13 of the state's 32 counties. Grant, Valencia, and Luna Counties account for 86.4 percent of the total production. During the investigation, 141 deposits were visited. A total of 72 character samples was collected for assay, and 3 larger samples were collected for bench-scale metallurgical tests. Results of these metallurgical tests indicate that an acid-grade product can be obtained with 95 percent recovery of the CaF2 content of the crude ore.

Jan 1, 1966

By Thomas Fraser, E. A. Holbrook

The data in this bulletin were obtained during an investigation of screening practice by the University of Illinois engineering experiment station and the United States Bureau of Mines under a cooperative agreement between them and the State of Illinois Geological Survey Division. Earlier work on this subject includes a study of the general practice of coal preparation in Illinois, made in 1914 and published in 1916/ and an investigation of Illinois coal-w.ashing methods, results of which were published in 1912 in a bulletin 2 that contained complete information on the methods then in use for sizing washed coa 1.

Jan 1, 1925

By M. G. Wallis

This report presents the results of a study to develop a detailed mining method design based on longwall mining with sublevel caving. The method is applicable to low-dipping coal seams 20 or more feet thick such as are found in the western United States. The report covers (1) the development and description of the mining method, (2) evaluation of the engineering feasibility of the design, (3) estimates of productivity and recovery, and (4) an engineering cost analysis and economic feasibility evaluation of the mining method design.

Jan 1, 1977

The domestic mineral and material industry grew in some key sectors and declined in others during 1993; overall, the industry was poised at yearend for stronger growth in 1994. Metals production is expected to increase with anticipated growth in U.S. motor vehicle sales. There also may be increased demand for industrial minerals in 1994 based on domestic highway and building construction. Additional information on events, trends, and issues in the mineral and material industry is presented below and in the commodity sections that follow. Overall Industry Performance The value of processed materials produced from minerals in the United States during 1993 is estimated to have been about $326 billion, an increase of 5% compared with that of 1992. The estimated value of U.S. raw nonfuel minerals production in 1993 was $31.6 billion, about 1 % less than in the preceding year. The value of domestic minerals production has risen in 28 of the last 33 years.

Jan 1, 1994