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By W. E. Webb

This report describes a method the Bureau of Mines devised for measuring the dielectric constant and loss tangent of low-loss minerals at microwave frequencies. Determina-tion of these properties makes it possible to predict the effects of using microwave heating in potential mineral processing applications. The method uses a test cell and radio-frequency (RF) impedance analyzer with automated data acquisition and analysis. In this initial phase of microwave heating research, the Bureau measured dielectric constants and loss tangents at frequencies between 100 MHz and 1 GHz. The objective was to establish a reliable data base for use in predicting the effects of microwave heating on minerals. Comparison with previously measured data showed the Bureau's measurement method to be accurate to within ± 3 pct. This report describes the method and discusses the preliminary results of the Bureau's investigations. Typical comparative data are included.

Jan 1, 1986

By Ronald Branstetter

Gaseous and particulate exhaust emissions from 20 diesel engines in service at five underground mines were measured with high accuracy instrumentation. The engines that were tested were checked for faults or maladjustments. The vehicle and engine maintenance organization was studied at each mine and an idealized maintenance program was devised. Faults were induced in a new diesel engine to determine their effect on the characteristics of the exhaust emissions. The results, conclusions and recommendations from this investigation are presented in this final report.

Jan 1, 1983

By Lulie H. Crump

U.S. supply and demand data for petroleum and natural gas liquids, by States and regions, were tabulated for the years 1960 and 1965. Estimates arcs provided of State-by-State quantitative data for the petroleum and natural gas liquids industry that can be integrated into State, regional, and national energy balances by source, form, and consumer sectors, and used for determination of interstate and interregional energy flows. Tables 1-4 show the estimated total supply of petroleum available for consumption and the supply's distribution among the major consumer demand sectors (household and commercial, industrial, transportation, and electricity generation). To obtain summary figures for the major proportion of refined products by States, individual tables were compiled for the six major products (tables 5-16). To enable comparison of petroleum data with those for other energy forms, conventional volumetric data in barrels were converted to their British thermal unit (Btu) equivalents. Interregional shipments of crude petroleum and theoretical flow patterns for petroleum products are shown in figures 1-4.

Jan 1, 1969

By Daryl R. Tweeton

This Bureau of Mines publication provides information to assist in selecting a lixiviant (leach solution) for in situ uranium leaching. The cost, advantages, and disadvantages of lixiviants currently used and proposed are presented. Laboratory and field tests are described, and applications of geochemical models are discussed. Environmental, economic, and technical factors should all be considered. Satisfying environmental regulations on restoring groundwater quality is becoming an overriding factor, favoring sodium bicarbonate or dissolved carbon dioxide over ammonium carbonate. The cheapest lixiviant is dissolved carbon dioxide, but it is not effective in all deposits. Technical factors include clay swelling by sodium, acid consumption by calcite, and the low solubility of oxygen in shallow deposits. Laboratory leaching tests can provide useful data. However, they can be misleading if, for example, the ore is allowed to oxidize before testing or if distilled water instead of formation water is used for making solutions for permeability tests. Geochemical models presently are more useful for indicating trends in solubility than in reliably predicting concentrations.

Jan 1, 1981

By John Paul Gries

This Bureau of Mines study outlines the history of 11 major metal ore deposits or districts that are relatively new discoveries. The oldest operation is the White Pine mine, where major exploration was initiated in 1929. Discovery (delineation of ore bodies) dates range from 1948 to 1976. All but two of the deposits, Quartz Hill in Alaska and Flambeau in Wisconsin, are or shortly will be in major production.

Jan 1, 1979

By R. B. Anderson

SULFUR poisoning of iron catalysts in the Fischer-Tropsch synthesis was investigated at the Bureau of Mines, because synthesis gas produced from coal contains sulfur compounds. Tests of two typical iron catalysts with synthesis gas containing known concentrations of H2S were made to determine catalyst life as a function of sulfur concentration to ascertain the type of gas purification required. Fixed beds of activated steel turnings and a fused iron oxide catalyst were investigated in sulfur poisoning tests at 21.4 atmospheres with IH2+100 gas containing 6.9, 23, or 69 mg S as H2S per cubic meter (0.3, 1.0, and 3.0 gr per 100 cu. ft.). In tests of reduced catalysts at constant temperatures, more than 80 percent of the activity was lost when 0.5 mg S/g Fe was introduced. Poisoning of nitrided or carbided fused iron oxide catalysts to a given extent required more than twice as much sulfur than for the corresponding reduced catalyst. When the synthesis temperature was increased to compensate for loss in activity, tests of the fused iron oxide catalysts at constant productivity could be continued for 19 to 98 days. The tests were terminated by clogging of the reactor, presumably caused by carbon deposition. One objective of the present work was to determine if synthesis gas, purified by the Bureau of Mines' hot-potassium carbonate process for removing H2S, OOS, and CO2, is suitable for synthesis on iron catalysts. The sulfur content of the gas purified by tills process is in the range of concentrations used in the present work. In constant-productivity tests of nitrided fused iron oxide catalysts with synthesis gas containing 6.9 mg S/m3, catalyst lives are nearly long enough for serious consideration of tills mode of operation. However, factors relating to selectivity and stability of the catalyst indicate that this type of operation is impractical for a commercial process. On this basis additional gas purification, such as iron oxide boxes following a hot potassium carbonate scrubber, is desirable.

Jan 1, 1965

By E. D. Gardner

The Bureau of nines, in cooperation with the mining companies of the Southwest, is conducting an investigating to ascertain the safest and most economical explosives to use in metal mines, and to ascertain the best methods of blasting under various conditions. A part of this investigation has been a study of drilling and blasting drift rounds in metal mines. This paper covers one phase of work on drift rounds and discusses the methods of loading the individual holes of the rounds. The blasting tests, on which this paper is based, were made at the Copper queen Branch of the Phelps Dodge Corporation at Bisbee, Arizona.

Jan 1, 1927

By S. C. Termes

To help develop the basis for new fine-particle separation methods, the Bureau of Mines has investigated the use of cross-linked starches containing four chelating groups--carboxylate, iminodiacetate, dietha-nolamine, and xanthate--as flocculants for selected metal oxide and hydroxide mineral fines. It was found that those starches capable of interacting with the mineral surface by a chemisorpti,on mechanism (as indicated by zeta potential measurements) produced the highest recover-ies and'grades of the metal oxide or hydroxide when flocculated from a binary mixture with quartz. The effects of pH, dispersing agent, stirring rate, stirring time, and starch dosage on selective flocculation were studied for binary mixtures of hematite and chromite with quartz. Floc strength becomes important in achieving maximum recoveries by mechanical postflocculation separations.

Jan 1, 1985

By John D. Spencer

Research on the development of new and improved methods for the discovery and production of oil and gas and production of fluid fuels from coal continued to be the major thrust of the Bureau of Mines energy research program during 1973. Crude oil recovery from tar sands and oil shale also retained a high priority in this work. Complementing this program were numerous studies aimed at accomplishing the objective of increased energy output with greater safety and minimum harm to the natural environment. This report summarizes research objectives and results and itemizes formal publications of the Bureau of Mines on energy and related subjects.

Jan 1, 1974

By Edmund Newton

The Haile mine has been the outstanding gold-mining operation and the largest single producer of gold in the Appalachian region. Gold was discovered at the Haile in 1827, previous to the present operation, production has been nearly $4,500,000 (gold at $20.67 per ounce.) from somewhat over a million tons of ore, with an average extraction of about 70 percent. The Haile property, now operated by Haile Gold Mines, Inc., is in the southern part of Lancaster County, South Carolina, 3-1/2 miles northeast of the town of Kershaw and 55 miles north of Columbia, the State capital. (See fig. 1.) The corporation has a lease and purchase contract on 1,805 acres, covering the present productive area. In addition, it holds lease contracts on 1,500 acres additional adjacent to this area.

Jan 1, 1940

By G. F. Kuncir

The analysis summarized herein evaluates the Bureau of Mines Program for Advancing Mining Technology Oil Shale in terms of the economic benefits which may be derived for the Nation as a result of its successful research and development efforts. On the basis of postulated oil shale production scenarios, benefit-cost ratio indicators are computed for the program elements as they apply to surface, underground, and modified in situ oil shale mining systems. Eight value indicators are used to measure the Program's beneficial impact on the future oil shale industry in relation to planned research and development costs. These are: capital cost savings, operating cost savings, labor savings, environmental quality maintenance cost reduction, reduction in production costs, byproduct production benefits, total production benefits, and additions to recoverable reserves. Program costs are aggregated from 1974 through 1987 and major benefits are accrued from 1982 through 2040. Both cost and benefit streams are discounted to mid-1975 present value.

Jan 1, 1977

By Daniel G. Di Canio

Reference information and user instructions for Version 3.0 of the Accident Cost Indicator Model (ACIM) software package are presented. ACIM estimates the tangible costs of occupational injuries, illnesses, and fatalities in the United States mining industry.

Jan 1, 1983

By J. L. Johnson

The U.S. Bureau of Mines investigated the recovery of tin and silver from the Coal Creek deposit in the Talkeetna Mountains, AK. Approximately 5 million st of reserves grading 0.2 pct Sn with silver credits of 0.2 tr oz/st have been delineated by drilling. A 10-to 25-pct Sn gravity concentrate was produced by treating the minus 20-mesh ore with a spiral, then regrinding to minus 65 mesh and tabling. Sulfide contamination in the gravity concentrate was as high as 60 pet. Sulfide flotation of this concentrate produced tailings containing 40 to 50 pet Sn. Overall recovery was 76 pct for tin but only 5 to 10 pct for silver because of losses during sulfide flotation. Other methods tested to clean the concentrate included cassiterite flotation, gangue flotation, nitric acid leaching, and wet and dry magnetic separation. Tin beneficiation tests on the minus 325-mesh fraction included cassiterite flotation, vanning, sulfide flotation, and fuming. The bench-scale and locked-cycle tests were used to estimate the mass flows for a 1,000-st/d plant.

Jan 1, 2010

By Howard B. Hamilton

Laboratory performance of mercury filled current limiting devices (CLD) used for high speed switching of DC circuits (600 volts and below, up to 1000 amperes) using a system involving a parallel connected vacuum switch with CLD and an additional series connected vacuum switch was verified in USBM Contract #HO 357079. This report details analytical work and field experimental tests to predict and control voltage surges associated with the high switching speed associated with the switching system. It also details tests conducted to demonstrate the fault current limiting ability of the CLD. Problems associated with designing a fault current limiting system are discussed.

Jan 1, 1978

By C. Özgen Karacan

Methane emissions from the active face areas and from the fractured formations overlying the mined coalbed can affect safety and productivity in longwall mines. Since ventilation alone may not be sufficient to control the methane levels on a longwall operation, gob vent boreholes (GVB), horizontal and vertical drainage boreholes, and their combinations are drilled and used as supplementary methane control measures in many mines. However, in most cases, the types of degasification wellbores chosen are decided based on previous experiences without analyzing the different factors that may affect this decision. This study describes the development of an expert classification system used as a decision tool. It was built using a multilayer perceptron (MLP) type artificial neural network (ANN) structure. The ANN was trained using different geographical locations, longwall operation parameters, and coalbed characteristics as input and was tested to classify the output into four different selections, which are actual degasification designs that US longwall mines utilize. The ANN network selected no degasification, GVB, horizontal and GVB, and horizontal, vertical and GVB options with high accuracy. The results suggest that the model can be used as a decision tool for degasification system selection using site- and mine-specific conditions. Such a model can also be used as a screening tool to decide which degasification design should be investigated in detail with more complex numerical techniques.

Jan 1, 2009

By E. P. Youngman

Before the World War the use of zirconium and its compounds was largely experimental and confined almost wholly to Germany and Austria . Occasionally small lots of zirconium ore had been produced in the United States ( 1,000 pounds in 1869 , 26 tons in 1883 , and 3,000 pounds in 1903 ) and used (with monazite ) in the manufacture of various lighting devices , especially incandescent gas mantles ; but it was not until 1906 that the discovery of the natural zirconium oxide in large quantities near Sao Paulo , Brazil , first gave promise that a zirconium industry eventually might be developed . Edward Rietz , who worked the Brazilian deposits , interested German chemists in extending the use of zirconium , and by 1911 trade journals were listing German firms as manufacturers of compounds or products derived therefrom . For a time zirconia was one of the various oxides used in the Nernst lamp . It was used also for crucibles and hearths as refractory material ; in the manufacture of chemical utensils ; in enamels ; in the place of bismuth subnitrate for defining Röntgenray pictures of the stomach ; as a pigment ; in medicine ; and in a number of other ways . The Germans were credited also with producing a remarkable zirconium steel , which , it was claimed , was much superior to other alloy steels . During the World War the United States Government investigated the possibilities of zirconium , as well as those of other steel -hardening elements , and a large automobile manufacturer actually purchased a substantial quantity of ore with the purpose of employing zirconium in automobile steels . Immediately after the armistice the Government ceased its investigations ; but despite the difficulties experienced by various investigators in reaching concordant results , interest in the use of zirconium as a steel -hardening agent , as well as in other uses of the element and its compounds , continued . In 1918 the Foote Mineral Co. , which had been interested in zirconium for several years , was exploiting the deposit in Brazil formerly worked by the Germans and was supplying zirconia in the form of ore , brick , and cement for refractory and other purposes . About the same time the Electro Metallurgical Co. , which before the entrance of the United States into the war was experimenting with zirconium alloys , supplied in tonnage quantities the demand for these alloys . In 1919 it was reported that American manufacturers , after several years of research, were producing in commercial quantities pure zirconium oxide , which was finding a place in the manufacture of small refractory articles , scorifying dishes , crucibles , tubes , and one- piece furnace linings . In 1920 the lowering of the price of zirconium metal powder ( because of improved metallurgical methods ) promised the production of the metal on a semicommercial scale . In 1924 the Titanium Alloy Manufacturing Co. introduced a new opacifying agent , " Opax , " made from zircon . A year or two later some of the large pottery manufacturers became interested in the use of zirconium oxide as an opacifying agent , the increased production of titanium pigments having resulted in the production of zirconium as a by-product at a price that could compete with tin oxide . In 1928 it was reported that the industrial use of zirconium oxide was increasing steadily in the manufacture of brick , crucibles , and other refractory products , such as high- temperature cements . However , the reluctance of producers to install additional and more suitable

Jun 1, 1931

By Robert I. Fujimoto

The work described was conducted to develop standards for the application of wire rope clips on wire rope. These standards include optimum number of clips and clip nut torques for wire rope sizes 1/4 through 2-1/4 inches, when used for forming an eye attachment in wire rope. Wire rope test specimens with clip attachments were load tested on tensile testing machines to determine an effective combination of clip nut torques and number of clips for each size of wire rope to develop efficiencies above 90 percent of the catalog ultimate rope strength.

Jan 1, 1973

By Donald J. Frendzel

The post-World War II expansion of the Soviet petroleum industry has established the U.S.S.R. as a major oil-producing nation and has led to Russian reentry into the international petroleum trade. The rapid growth of Soviet petroleum production will allow the U.S.S.R. to displace Venezuela as the world's second largest oil-producer in 1960 and to narrow further the gap between Soviet and U.S. crude-oil production. U.S.S.R. crude oil output was only a tenth of U.S. production in 1946, but it will be more than a third at the end of 1960 and more than half in 1965. The Soviet Seven-Year Plan (1959-65) for oil provides for substantial increases in petroleum production, refining, storage, and distribution facilities. Crude oil production and primary distillation capacity are to double, considerable storage capacity is planned, and pipelines for crude oil and petroleum products are to increase threefold. According to the Soviets, the initial phases of this plan (1959 and 1960) have been completed successfully. However, this progress has been achieved with difficulty.

Jan 1, 1961

By Donald James Butler

Problems resulting from underground mines in three inactive mining districts in Colorado were investigated. The purpose was to determine how these problems could be reduced or eliminated in new closings -- essentially by benefitting from lessons of the past. Mines in Leadville, Westcliffe and the Cripple Creek-Victor districts were evaluated. Two basic types of problems were found to exist in the districts: environmental degradation and hazardous conditions. Environmental problems result largely from acid and toxic drainage from the runes and from leaching of surface waste rock piles and mill tailings impoundment. The acid drainage contributes high levels of metals to streams and deposits sediment in the stream bottoms. Erosion of waste piles is a lesser problem. Hazardous conditions from open or improperly sealed mine shafts and adits, mine subsidence pits, and from deteriorating and unsafe surface structures are common to the three districts. These problems become worse with the ravages of time and vandalism. Engineering solutions which would correct or reduce many of these problems are presented. These recommendations should also be applied to new mine closures, however, more basic changes are needed to effectively implement improved mine closures. The changes must take place in the areas of legislation, mining practices and education. Legislated regulations should realistically reflect the needs of both the mine operators, protection of the environment and the best interest of the general public. Benefits should be provided for compliance with regulations instead of penalties being assessed for noncompliance. Hazardous conditions and environmental problems associated with mines can be alleviated through improved mine design and effective cloning procedures. Education should provide an appreciation by the general public of past and present problems facing mine operators. This will result in an improved mining climate which, in turn, will insure a continuing supply of minerals to meet increasing needs.

Jan 1, 1983

By D. E. Welcome, T. W. McDowell, R. G. Dong, S. F. Wiker

Workers using vibrating hand tools have the potential for developing health problems associated with repeated forceful actions and exposures to hand-transmitted vibration. Hand-arm vibration syndrome (HAVS) and other hand-arm system disorders have been associated with such exposures.1-2 To better assess health risks, comprehensive evaluations of these exposures must include quantitative assessments of hand-tool coupling forces; unfortunately, no standardized method for quantifying hand forces exists. Handle instrumentation may be ill-suited for some field environments. Psychophysical force-recall techniques may provide alternatives to handle instrumentation. A thorough understanding of the effects of vibration and other factors on force-recall accuracy and reliability is important before such methods are applied in risk assessments. Methods In this study, the effects of vibration and other factors on the accuracy of psychophysical force-recall were explored in two experiments. Twelve male subjects participated in the first experiment. The second experiment employed 20 participants (10 female, 10 male). In each experiment, participants applied specific grip and push forces to an instrumented handle mounted on a shaker system. Participants were exposed to sinusoidal vibration at frequencies that ranged from 0 Hz to 250 Hz. Three levels of applied force (low: grip = 15 N/push = 25 N, medium: grip = 30 N/push = 50 N, and high: grip = 45 N/push = 75 N ) and two levels of vibration magnitude (low: ANSI 4-8-hr limit and high: ANSI <0.5-hr limit)3 were examined. During the vibration exposure period, participants were provided with visual feedback while they attempted to “memorize” the applied grip and push forces. At the conclusion of the vibration exposure/force memorization period and a controlled rest period, the participants tried to duplicate the grip and push forces on a non-vibrating handle without the aid of visual feedback. The effects of different vibration frequencies, vibration magnitudes, and grip and push force levels were tested in a random order from trial to trial. Results Participants tended to overestimate grip and push forces. Depending on exposure conditions, error means ranged from 2 N to 10 N. The ANOVA revealed that force-recall errors for exposures between 31.5 Hz and 63 Hz were significantly higher than those at other vibration frequencies (p < 0.05). The frequency effect is depicted in Figure 1. Error means were greater when participants were exposed to the higher vibration magnitude (mean = 9.1 N, 95% CI = 8.2-10.1 N) when compared with the lower vibration magnitude (mean = 4.9 N, 95% CI = 3.9-5.8 N) (p < 0.05). The effect of vibration magnitude is shown in Figure 2. The average error for

Jan 6, 2006