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By Arcy, D&apos Banister

The productive potential of the Nation's principal active and inactive silver mining districts has been evaluated, using 1964 economic conditions and assumed silver prices ranging up to $3 per ounce. On this basis, the United States has an estimated 5 billion ounces of unmined silver, excluding minor byproduct silver in gold deposits. Approximately 3.5 billion ounces are contained in deposits requiring higher silver prices to be economically minable, and about 1.3 billion ounces are in currently operating mines. An analysis of silver consumption trends since 1954 indicates that the free world industrial market will climb to nearly 800 million ounces annually by 1985. U.S. industrial silver consumption has been projected to increase at an annual rate of 4 percent from 1965 to 1985. Average annual increase for the remainder of the free world has been 8.1 percent since 1953; this is expected to level off with an estimated average increase of 5 percent to 1975 and 4 percent from 1976 to 1985. Foreign silver production has, in the past, exceeded consumption, but in 1960 the supply deficit was over 100 million ounces. U.S. production, also traditionally exceeding demand, was suddenly overtaken at the start of World War II. By 1964 the annual deficit, excluding coinage, was over 84 million ounces. World coinage requirements of silver are fast declining and expected to total only 25 million ounces annually by 1985. In fact, coins are already becoming major short-term source of silver to fill the large deficit between industrial demand and current production. The larger, long-term deficit (to 1985, the limit of this study) must be balanced by silver from the hoards and new production from silver deposits. Eventually all of the deficit must be met by new production or silver prices will rise until consumption is greatly curtailed. To balance free world supply and demand, it is estimated that the free world must produce an additional 85 million ounces by 1975 and 375 million ounces by 1985. The estimated proportion expected from U.S. deposits is 17 million ounces by 1975 and 74 million ounces by 1985.

Jan 1, 1969

By J. J. Pfeiffer, J. W. Myers, A. A. Orning

A study was made of the feasibility of using washery refuse in the manufacture of lightweight aggregate for building materials . Preliminary caking and burning tests showed that the refuse could be converted into lightweight aggregate but that refuse passing a No. 14 U.S. Standard screen could not be used without additional processing . The aggregate was prepared by pelletizing the refuse and burning out the carbonaceous material on a chain- grate in a refractory - lined furnace . A small stationary - grate furnace was used to study the process variables involved and establish optimum ignition and combustion conditions . Maximum ignition rates were obtained at air rates of approximately 200 lb per sq ft hr , but air rates of 450 or higher were required in the burnout period to obtain temperatures high enough to sinter the ash . The data obtained from this unit were used as a guide in the operation of the chain- grate furnace . In the chain - grate furnace , satisfactory results were obtained by using primary air rates of 200 lb per sq ft hr in the ignition zone and 500 lb per sq ft hr in the burnout zone . The ignition- zone air was preheated to 500 ° F , but the air for burnout was not preheated . A total of 2-1/2 tons of aggregate was prepared in this unit and made into experimental block . A commercial development based upon the results of this study yielded a product which met the ASTM specifications C 130-42 for lightweight aggregate , and blocks made from the aggregate were of good color , durable , and light - inweight .

Jan 1, 1964

By F. P. Haver

Primary lead is produced in the United States by the pyrometallurgical smelting of lead sulfide (galena, PbS) concentrates, which poses sulfur dioxide and lead air pollution control problems. The Federal Bureau of Mines has investigated an alternative hydrometallurgy procedure that does not generate gaseous sulfur oxides and diminishes the potential for the escape of lead into the atmosphere. The procedure involves leaching galena flotation concentrates with ferric chloride (FeC13) solution to obtain lead chloride (PbC12) and elemental sulfur as expressed by the following chemical reaction: PbS + 2FeC13 ? PbC12 + 2FeCl2 + S°. At 100° C, over 99 pct of the PbS in the concentrate is converted to PbCl2 in less than 15 min. The leach solution, composed of brine (NaCl) containing slightly more than the theoretical required amount of FeC13, dissolves the PbC12 as it is formed, leaving a residue of elemental sulfur plus gangue. High-purity PbC12 (>99.9 pct) crystallizes from the leach filtrate on cooling and is electrolyzed in a low-temperature, fused-salt cell to obtain corroding-grade metal (>99.94 pct Pb). Spent leach solution (FeC12) is regenerated for further use by reaction with the chlorine obtained in the electrolysis of lead chloride. Other values, such as Ag, Cu, Zn, and S°, are recovered by additional treatment of either the leach solution or leach residue.

Jan 1, 1976

By Eric H. Brown

One of the best methods by which the results of accident-prevention work can be measured for any particular period is to keep an accurate record of the accident experience, which may then also be compared with the experience of others. The purpose of this report is to compare records of the salt-mining companies operating in Louisiana, and their assistance in making available their accident records is gratefully acknowledged. PRODUCTION Four companies produce salt in Louisiana -Avery Salt Co., Avery Island; Jefferson Island Salt Mining Co., Jefferson Island; Myles Salt Co., Weeks; and Carey Salt Co., Winnfield. Three of these companies operate within 30 miles of each other in the southern part of the State, and the other operates in the central part.

Jan 1, 1938

By R. B. Stotelmeyer

Mineral resources, or a potential for their discovery, occur at 34 localities in the Glacier Peak Wilderness and adjacent areas of the north Cascade Range of Washington (see plate). Eighteen of the mineral deposits are in the established Wilderness, four are in or partly in contiguous RARE II (Roadless Area Review and Evaluation) lands recommended by the Forest Service for addition to the Wilderness (A, D and G6031.), three are in adjacent RARE II lands excluded from wilderness consideration, and nine are in nearby roaded areas excluded from the RARE II inventory. Mineral commodities that might be produced from the Wilderness and recommended additions are gold, silver, copper, lead, zinc, molybdenum, arsenic, cadmium, tungsten, cobalt, limestone (marble), pumice, and volcanic cinders. Mineral production from adjacent lands might include most of these commodities, plus antimony, decorative stone, pyrite, silica, and garnet.

Jan 1, 1982

VOLUME II Volume II, in conjunction with Volume I, is a general guide to the selection of cost-effective methods of site data acquisition in all geologic environmental, and socio-political circumstances. The judgement of a generalist or trained specialist must be relied upon in the final analysis to design the optimum program for a specific site.

Jan 1, 1976

By A. W. Hall

A nuclear method was developed for continuously and automatically deter-mining the moisture content of coal flowing through a bin. Fast neutrons from a 1 curie americium-beryllium source penetrate the coal, are thermalized (slowed down) by hydrogen in the moisture, and are counted by a thermal neutron detector. The difference between the number of these thermal neutrons and those thermalized by dry coal (in a reference drum) is a measure of the moisture content of the coal. A materials handling system was developed and in tests at a commercial coal preparation plant, moisture in coal was monitored continuously within 0.2 percent of values determined by conventional means. The meter responded rapidly to change in moisture content, making it adaptable to automatic process control, and was operated for 1 year without malfunction or recalibration. Shielding of the source by the coal kept the neutron flux level at the bin wall less than 1 milliroentgen per hour, a safe level for personnel.

Jan 1, 1973

By Haskiel R. Shell

Methods of chemical analysis of clays for the following constituents are presented: moisture, ignition loss Fe2O3, TiO2, P2O5, CaO, MgO, Na2O, K2O, total. carbon, carbonate carbon total sulfur, soluble salts, and soluble sulfate. In these procedures the attainment of accuracy has been the primary consideration sample was taken to insure accuracy, with ordinary precautions. The procedures may therefore be somewhat somewhat and will not be suited for routine work on samples for which the approximate analysis is already known and in which the need for accuracy is not very exacting. However, the method shod be as a set of detailed directions, that have been tested and shown to yield accurate results with clays and other aluminum silicate minerals. Among these minerals are clays of all types, bentonite bauxite, shale, brick; soil, calcined refractory, and sand. Although some of the methods are Unusual, no particular claim is laid to originality. The material was drawn frail many sources, put together and tested.

Jan 1, 1949

By H. H. Yancey

In this information circular is presented a summary of the more important articles that nave appeared in the literature pertaining to the experimental work and to the commercial operation of the froth-flotation and Trent processes as applied to the cleaning of fine coal.

Jan 1, 1933

By Ronald T. Mayerle

In 1986, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied a 20,500-acre part of the 104,085-acre Rincon Wilderness Study Area (OR-002-082) in order to evaluate its identified mineral resources. The wilderness study area is located in Harney County, OR, about 12 miles west from Fields. No mineral resources were identified within the study area. A literature search found no records of mining or minerals exploration, nor did a ground search find any evidence of mining-related activity. Of seven alluvial samples taken from the major drainages of the study area, all were barren except one. This sample, taken from a dry streambed along the southern boundary, contained $0.07 gold per cubic yard; however, this small amount of gold is of no economic significance, and the source is probably outside the study area. The Pueblo-Steens mining district extends to within 4 miles east of the study area. No evidence of geological environments similar to those that were responsible for the formation of resources or occurrences of metals and nonmetals within the district is known within the study area.

Jan 1, 1987

By Elbridge W. Gresseth

Rock deformational structures in a deep mine were analyzed by petrofabric techniques to learn (1) the relative magnitude and direction of the principal stresses involved in tectonic deformations prior to mining, (2) the preferred orientation of rock planar discontinuities which define rock anistropy prior to mining, and (3) the relationship of mining-induced rock failure to inherent rock stresses and inherent rock anisotropy. Rock fabric elements used for petrofabric analysis consisted of bedding planes, faults, joints, fractures, foliation, sericite plane (001), quartz axis [0001], quartz deformation lamellae, and microfractures. Structures and structural symmetries from different areas within the mine and from different scales of observation were compared to learn the nature of rock anisotropy and the orientation of the principal stresses defined by rock deformations. Analysis of such fabric as regional and macroscopic faults, b-c joints, quartz [0001], sericite (001), and microfractures, indicate that during the epochs of tectonic deformation, the maximum and minimum principal stresses were horizontally oriented and acted along northwest and northeast axes, respectively. This condition of regional stress appears to have continued during folding and the associated period of faulting. The most recent tectonic deformation represents a rotation of the minimum principal stresses into a vertical position, as shown by the development of a tensile joint system, quartz deformation lamellae, and microfractures. Good interscale correlation and statistical homogeneity of tectonic fabric indicate a stress field homogeneity in this area during tectonic deformation. Rock physical anisotropy is genetically associated with tectonic fabric and consists of preferentially oriented planar discontinuities intersecting along a nearly vertical axis. The mining-induced deformations were correlated with the inherent rock anisotropy which either directly controls or greatly affects their development. This phase of rock deformation shows a greater degree of stress field heterogeneity than was the case with tectonic deformations This is explained as a result of nonconfinement afforded by underground openings and the increase in ground stresses due to mining activity"

Jan 1, 1968

By Merle L. Bowser

An alinement (steering) sensor for continuous mining machines has been developed under a Bureau of Mines contract. A laser source in the entry projects a beam parallel to the centerline of the entry. The beam is optically shaped to a narrow, vertical fan and illuminates an array of optical sensors bunted on the mini machine. These sensors interpret the location of the beam into meter readings of heading (angle) error and lateral displacement errors. The system, which was tested for 5 months in an operating mine, appears to be fundamentally sound, and with some modification, should be applicable to remote or automatic guidance of continuous miners and other machines.

Jan 1, 1976

By W. H. Tomlinson

One of the more important functions of the Federal Bureau of Mines is conservation of the life and health of employees of the mineral and allied industries. Since its very beginning the Bureau has encouraged competition between mine rescue and first-aid teams as a means of stimulating interest in safety and accident-prevention work. In addition to sponsoring competition on a national and international scale during the past 45 years, the Bureau has also assisted State mining departments, mining companies, and mining organizations in holding State, district, company, and other local meets. This assistance includes providing instructors to train teams, judges, and other contest officials. The Bureau has also furnished problems and outlines for working them, judges I discount sheets (scorecards), contest rules, and problem judges. In fact, Bureau representatives participate in nearly all State, district, and company contests and have bad complete charge of some contests.

Jan 1, 1956

By Theodore R. Jolley

The estimated recoverable reserves in the area in the vicinity of Eska 2 mine are, 699,300 tons in the Chapin and Emery bas of the Maitland group. Those recoverable reserves are in the area between the Eska fault zone and Jonesville fault and extend down dip from the outcrops. No reserves were developed by the Eska 2 entry or by drill hole 14-16 in the Eska fault zone. The small quantity of reserves in the vicinity of the Eska 2 mine is insufficient to justify development of a now, modern .nine in this area. The estimated recoverable reserves in the area east of aka Creek are 974,500 tons in the Eska, Shaw, and Martin beds of the Eska group. Most of those reserves occur in the south limb of the syncline. It will be necessary to practice subjacent mining methods to recover these reserves in the Eska group. The Eska bed developed by the diamond drilling in this area comprises coal end few thin partings. The Shaw and Martin beds comprise two bunches of coal separated by partings, and the product from full-bed mining will require thorough preparation.

Jan 1, 1952

By W. L. Hunter

The research on this report was conducted to obtain information on the feasibility of producing ferro chromium of varying silicon and carbon contents from domestic chromite. Concentrates from the Mouat deposit were chosen because they typify the chromite found in the Stillwater complex, the largest domestic reserve, and are similar in composition to other extensive North American and foreign deposits. Batch-smelting tests designed to produce high-, medium-, and low-carbon ferrochromium were made in single phase and three-phase, electric-arc, steelmaking furnaces. Agglomeration studies were made in a rotary kiln. Continuous smelting tests were made to yield data on the production of high-carbon ferro chromium and low-carbon ferrochromium-silicon. The carbon content of high-carbon ferrochromium was lowered to the medium-carbon range by oxygen injection. Mouat stockpile concentrates were nodulized in a gas-fired rotary kiln using quartz, limestone, and fluorspar additions in the proportion necessary to flux the slag. The nodules were smelted in a continuous test using coal, coal char, and mixtures of the two consecutively as reductants.

Jan 1, 1961

By Arthur Crowfoot

This paper describing t o concentrating practice of the Phelps Dodge Corporation, Morenci Branch, at Morenci, Ariz., is one of a series of articles on concentrating methods and posts being prepared by the Bureau of Mines. The Morenci concentrator, locally known as No. 6 concentrator, treats 5,000 dry tons of ore per 24-hour day by primary tabling followed by two stages of flotation treatment, at 48-mesh size and 65-mush size respectively.

Jan 1, 1931

By L. B. Pankratz

Thermodynamic data on the elements and oxides were reviewed, evaluated, and compiled at the Bureau of Mines Albany Research Center. Values for Cp°, S°, H° - H°298, - (G° - H°298)/T, ?HP, ?Gf°, and log K are given in tabular form. Cp°, H° - H°298, ?Hf°, and ?Gf° are also expressed algebraically. Examples of calculations using these data are given.

Jan 1, 1982

By Robert Torbin

The objectives of the Continuous Shaft Lining (CSL) System are to reduce the costs, safety hazards, and time currently required in lining mine shafts with concrete. The CSL will line machine bored shafts downward from the shaft collar on a continuous basis using an inverted, pressurized slipforming technique. The technique for slip-forming downwards has been demonstrated and refined under this program. The approach taken involved laboratory scale testing of key features of the CSL concept. These feature tests included concrete distribution, concrete sealing, concrete slipforming and development of a reliable concrete mix. Based on these results, a full scale above-ground test facility and CSL were designed and fabricated. The objectives of these tests were to demonstrate the viability of the basic concept; to establish operating limits; and to provide input data and information for the design of a second generation shaft lining system. The results of the program have led to a CSL design and operational philosophy which will need to be tested in an underground environment before industry will accept the technology. However, the next generation CSL promises to meet all the original program technical objectives.

Jan 1, 1983

By R. A. Cattell

The peacetime activities of the Bureau's petroleum and natural-gas program have been reoriented to serve the needs of a national-defense program. When the United Nations sent troops to Korea after the North Korean Army crossed the 38th parallel in the latter part of June 1950, the Bureau's coordinated national program on petroleum and natural gas, with each major project forming an essential member of its framework, was carefully reviewed by those in charge of the work. As a matter of fact, the era of normalcy in which the petroleum and natural-gas research of the Bureau of Mines prospered during the fiscal year 19502/ was no sedative to the need for alertness on a national-defense front. The program, although conducted along peacetime lines in general, was scanned critically and repeatedly during that period to see where - if the need should arise -the emphasis could be shifted from peace to defense or war. Judging from the experience of two wars, it would not be long before the Bureau would be asked to use its trained technical personnel in applying techniques already learned in peacetime research to the requirements of munition and fuel needs of national defense. Near the end of January 1951, petroleum and natural-gas engineers of the Bureau of Mines began a comprehensive study of reservoir conditions in the Canyon Reef fields of Scurry, Borden, and Kent Counties, Tex. This work was preceded by published analyses of crude oils from Scurry County as early as April 1950. Well-informed persons in industry have estimated that these fields hold reserves that will yield 3 to 6 billion barrels of stock-tank oil. Although generally accepted good operating practices have been followed, engineering tests have shown that the natural energy, except in some favorable parts of the reservoir, will not be adequate for obtaining a high percentage of recovery. Correct information regarding the extent and availability of this vast reservoir of hydrocarbons is therefore of great concern to the Petroleum Administration for Defense in carrying out its responsibilities under the Defense Production Act.

Jan 1, 1952

By Ludwig Schmidt

Large quantities of gasoline are lost each year by evaporation from bulk-storage station tanks. The rate of evaporation from bulk-station tanks is influenced by two principal factors: First, the vapor pressure of the gasoline in the tank; and second, the amount of "breathing" of the tank. The vapor pressures of the gasoline govern the amount of the gasoline vapor in the air-vapor mixture above the gasoline in a tank at a given temperature. This is one of the principal factors in determining the total pressure of the air-vapor mixture within the tank. The "breathing" of the tank is caused by the inflow of air from the atmosphere during certain periods of the day and the expulsion of the air-vapor mixtures at other times, caused by atmospheric variations. The pressure built up within a tank and the amount of gasoline in the air-vapor mixture are both a direct function of the temperature existing within the tank. Therefore, two of the most common methods for reducing evaporation losses from bulk-station tanks are: (1) The use of vapor-tight tanks equipped with relief valves and operated at 1 or 2 ounces of pressure and about 1/2-ounce vacuum; (2) reducing the temperature of tanks and their contents by painting them a light color, by insulation, and in some instances by using water sprays. Water sprays, although effective, usually are too expensive to operate economically. In order to determine and compare the effects of various colors, insulation, and pressure in reducing the evaporation losses of gasoline held in storage in bulk-storage tanks, the Bureau of Mines made observations from May 29 to October 15. 1930, on five horizontal tanks of 12,000-gallon capacity each, which were erected at the plant of Black. Sivalls and Bryson Manufacturing Co., Kansas City, Mo. This report gives in detail the results of these evaporation tests.

Jan 1, 1931