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By J. M. Riley

The Bureau of Mines investigated a promising new technology for recovering A1203 from alunite to support the Bureau's alumina miniplant project. Results are presented for a study of the technical feasibility of treating alunite crushing and grinding reject fines for recovery of A1203. Alunite pellets having sufficient strength and resistance to degradation were produced by combining fines and coarse alunite with a KOH binder. The best pellets were prepared, in a laboratory pelletizer, by adding 1 pct KOH as a 5-pct solution to a mixture of 40 pct alunite dust (98 pct minus 65 mesh) and 60 pct coarse alunite (minus 20 plus 65 mesh). Calcines suitable for K2SO4 and A1203 recovery were produced by reducing dehydrated alunite pellets with sulfur in a laboratory shaft furnace for 4 h at 600° C, followed by air oxidation of the reduced calcine for 1 h at 600° C. This report presents design calculations, schematic diagrams, and discussions of the essential features of a proposed process research unit (PRU)--a continuous, 6-lb/h alunite shaft furnace--for studying the process.

Jan 1, 1983

By D. Hinton, M. McCawley, R. C. Lantz, F. Pisano, C. Stanley

"INTRODUCTION Aerosols (5 um have not been shown to be consistently generated and characterized in inhalation chambers. Particle deposition in the lungs however may occur with particles as large as 25 um(1). Therefore, in order to closely simulate the atmosphere of an underground coal mine where the distribution is bimodal, with modes at S and 15 um (2), particles much greater than <1 um must be characterized for uniform mixing and size distribution within these chambers. The Hazelton Animal Exposure Chamber has been chosen because it has been best characterized for smaller particles (<1 um) (3), and is the major type used by most inhalation toxicology institutes such as Lovelace Inhalation Toxicology Institute and Battelle Northwest Laboratory.BACKGROUNDPreviously published studies on the inhalation of solid aerosols have attempted to characterize the distrition of particles of <2 um in diameter. There are no published reports of extensive work characterizing either the size distribution of particles <1 um or the concentration throughout the exposure chamber (Table 1).Table 1 shows the variability and sizes of several aerosols <1 um in diameter used in five previous chamber studies.Discussion of Previous StudiesThe study done by Bauermash, Bryan, Dickinson, and Burke (4)stated two major concerns in the development of the 6.5 ft. diameter chamber. The first was that a quantity of animals could be exposed to the same concentration regardless of the location of the animal, and second was that the chamber could be easily cleaned and decontaminated. The solution to the first concern required a circular chamber with the contamination air entering the chamber somewhere along the central axis. The animals could then be changed during exposure time so that each animal was exposed throughout the total volume."

Jun 1, 1988

By Robert C. Gabler

Evaluation of incinerated sewage sludge as a secondary resource for aluminum, phosphorus, and minor constituents such as copper and zinc was initiated as part of the Bureau of Mines secondary resource program. The elemental composition of sludge ash for 14 plants in 11 U.S. cities was determined. Comparing industrialized cities with cities where most of the sewage is domestic, significant differences in heavy metal content were noted. Various parameters were investigated affecting the extraction of metals and phosphorus from a typical industrial city sludge ash and from a Palo Alto, Calif., sludge ash with a high precious metal content. Three extraction-recovery procedures for metals and phosphorus using sulfuric acid leaching, ion exchange, and various precipitation techniques were investigated. The last procedure developed was a combination approach using a three-stage countercurrent sulfuric acid leach that recovered most of the economic values from the sludge ash and also removed the leachable fraction of elements of environmental concern.

Jan 1, 1979

By John S. Berber

Acids, neutral oils, and pitch were produced by distillation of low-temperature lignite tar and processed to upgrade them into more valuable products: The acids were separated from the distillate and catalytically dealkylated to produce phenol, cresol, and xylenol. Aromatic and naphthene fractions of the neutral oil were converted into phthalic and maleic anhydrides by catalytic hydrodealkylation and vapor- phase oxidation. Paraffins and n-olefins from the neutral oil were processed into alkybenzene sulfonate, a biodegradable substance. Aromatic materials from the neutral oil were also extracted with organic compounds and the extract hydrogenated under pressure to produce jet fuel. The pitch was processed by various means to change its characteristics and make it suitable for similar applications as high- temperature tar pitch, including preparation of carbon black and metallurgical electrodes. In most cases, products obtained from the low-temperature tar were examined for physical and chemical characteristics and for potential commercial utility. Information obtained from this research would be helpful if a new coal- chemical industry based on tar utilization were established.

Jan 1, 1973

By W. K. Collins

Engineered scavenger compounds (ESC&apos;s) developed by the U.S. Bureau of Mines are a novel class of compounds that selectively can recover a desired element from a solid or molten alloy. Lithium titanate (L2Ti307 or Li2O?3Ti02) is used as an ESC to recover lithium (Li) from aluminum-lithium (Al-Li) alloys. X-ray diffraction measurements have shown that Li2Ti307 undergoes a phase change during scavenging from an orthorhombic structure to a hexagonal structure. This change is due to the incorporation of lithium in the matrix of the material and the effect of temperature. Although both phases are metastable, the hexagonal phase that forms during the scavenging of lithium from Al-Li alloys appears to be the more stable phase. Recovering lithium from the ESC by electrodeposition does not cause the structure to revert to the orthorhombic phase. The orthorhombic and the hexagonal structures of Li2Ti307 have similar scavenging capacities for lithium. This report proposes a new mechanism for the phase transformation.

Jan 1, 2010

By Lucia Kuizon

In 1986 and 1987, at the request of the U.S. Forest Service, the U.S. Bureau of Mines studied the Diamond Peak area comprising 183,000 acres in the Challis and Targhee National Forests in order to evaluate its identified mineral resources. More than 3,000 mining claims were located in three mining districts between the years 1882 and 1986. Approximately 230 mining claims in and the 150 claims adjacent to the study area were current in 1986, when Bureau of Land Management mining records were researched for this study. A total of 1,270 samples were collected from these sites (30 were for alluvial placer). Results of the investigation help determine the suitability of the study area for inclusion into the National Wilderness Preservation System. Lead-, silver-, zinc-, copper-, and gold-bearing minerals occur as veins and replacement bodies in shear and fault zones in Precambrian and Paleozoic calcareous Sedimentary rocks that have been complexly folded and faulted. Total production from the three mining districts in the study area was more than 150,000 tons of ore between 1901 and 1982. Approximately 11,600 tons of subeconomic resources consisting of lead, silver, zinc and copper were identified within the area. Over 37,500 tons of lead and zinc subeconomic resources were identified just outside the area. In addition, lead-, silver-, and zinc-mineral resources were identified at 4 mines within 2 miles of the study area. Iron mineral resources were also identified just outside the area.

Jan 1, 1991

By E. H. Denny

The presence in the Cripple Creek district, Colo., of irrespirable gas or gases, generally known to consist mainly of nitrogen and carbon dioxide, has been recognized by members of the mining industry in that region almost since underground mining was begun there; the occurrence, origin, and possible control of these gases have been discussed in several articles cited at various places in this report. Similar gases have also been studied in other metal-mining districts, as later discussed. In March, 1925, there were two fatalities from rock-strata gases in the shaft of the Index mine, near Cripple Creek. Two men repairing the bell or signal line preparatory to reopening the shaft were lowered into irrespirable gases and died. Their bodies were recovered by rescue crews from the United States Bureau of Mines and .the Portland mine, Victor, Colo. These crews found it necessary to use oxygen breathing apparatus. In October of the same year a miner was trapped on the 6 level of the Midget mine by an influx of gases that filled the shaft to a point above that where he was working. Oxygen breathing apparatus was again used by Bureau of Mines employees, who were in the vicinity, and the man was brought out in time to save his life. These two fatalities and one near fatality seemed to show that additional investigation of the gases and methods of control might be warranted. Accordingly, field and laboratory studies were begun by the authors of this report after a visit to the district by M. van Siclen, then engineer in charge, mining research division, Bureau of Mines, and after conferences with the Mine Owners&apos; Association of Cripple Creek and with J. T. Joyce, metal-mine commissioner of the State of Colorado. The mine operators of the Cripple Creek district and the State mine commissioner&apos;s office gave whole-hearted cooperation in this work.

Jan 1, 1930

By William Y. Mo

This Information Circular provides a detailed background documentation of how the Bureau of Mines projects U.S. mineral demand to the year 2000. These statistical projections serve as a quantitative basis for contingency forecasting of the low, high, and probable U.S. demand for nonfuel minerals by end-use categories and are published in the Bureau of Mines Mineral Commodity Profiles and Mineral Farts and Problems series. Aluminum is used as an example in this study.

Jan 1, 1980

By S. E. Khalafalla

In support of its goal to maintain an adequate supply of minerals to meet national economic and strategic needs, the Bureau of Mines has investigated a novel hydrometallurgical system with sulfur dioxide. Differential leaching with dissolved SO2 of manganese, nickel, and cobalt from their hydrous oxides was found to be very rapid and efficient--almost instantaneous and quantitative. In this method a given weight of mixed oxides previously ground to minus 200-mesh is slurried with a leach solution containing a specified quantity of dissolved SO2 for 10 minutes at room temperature and ambient pressure. An empirical leaching parameter, R, is defined as the ratio of the number of SO2 moles in the leaching solution to the weight of the metal oxide charge. Plots of the variation of metal extraction with the ratio R generate a series of sigmoidal-shaped curves, each of which is characteristic of a specific metal extraction. A threshold value of R is required to initiate the leaching of a given metal from the mixed oxides. Once this threshold is reached, the metal recovery can increase to more than 95 pct in very short times. For increasing values of R, the extractability of various metals by SO2 follows the order: Mn > Ni > Co >> Fe, Al, Cu. Differences in the threshold R values permit a variety of metal separations to be made simply by adjusting the quantity of SO2 in the contacting solution. Success in this leaching system depends upon comminuting the sea nodules to less than 0.149 mm (100-mesh). Above this critical size, leaching is slowed due to the inaccessibility of inner particle reacting groups to the SO2 leaching agent. This results in nonselective extraction and less extraction of preferred metal values. At or below 0.149 mm, leaching by SO, is possible with all its attributes of selectivity, sensitivity, and rapidity. Leaching with HC1 solutions of the same pH level as dissolved SO2 yielded mixed, slow, and incomplete metal extractions. This observation rules out any interpretation based on hydrogen ion as the leaching agent. The leaching curves resemble the complexometric titration curves of heavy metals with specific coordination species.

Jan 1, 1981

By G. L. Oldright

As sponge iron is much like porous, coarse sand, it is a tempting material to use in place of coarse scrap iron as a precipitant of metals, for scrap iron is relatively awkward to handle and exposes only a small amount of surface to pregnant solutions. The results of the experiments described in this bulletin are largely a record of the behavior of sponge iron as a precipitant of lead and copper under laboratory conditions comparable to those that would obtain in a commercial plant were it attempted to secure the maximum contact of surface between solution and precipitant. Physically, the study is largely one of the rates of diffusion of the metal ions in the solutions and through the metallic coatings surrounding the sponge iron particles. The practical objectives are to remove completely the valuable metals from solution and at the same time to obtain a precipitate of good grade. In order to fulfill this latter requirement, the precipitant should be almost completely consumed. These practical ends are usually secured by having the two substances involved pass each other counter-currently-that is, in such a manner as to have the strongest precipitant in contact with the most impoverished solution, and vice versa. EXPERIMENTS WITH LEAD SOLUTIONS In nearly all of the schemes involving the leaching of lead from its ores the metal has been put into solution as the chloride, and fairly concentrated liquors have been employed. The solubility of lead under such conditions is comparatively small at best; the hot pregnant liquors from which the metal is to be precipitated are then made nearly saturated with respect to lead, and only a very small amount of acid is used. Therefore it was not as necessary to learn the behavior of the sponge iron in precipitating lead from solutions of widely differing composition as to learn under what conditions, and with what mechanisms, this precipitation might be carried out most readily.

Jan 1, 1928

By W. J. Fene

A comprehensive study of all bituminous coal-mine fatalities occurring in Pennsyl¬ vania during the 5-year period, 1926-1930, was made to try to determine the factors that in¬ fluence accidents which cause these fatalities. During this study some two thousand reports of fatalities were reviewed, and pertinent information as to causes and influencing factors were tabulated therefrom. These tabulations are discussed in detail, and in some instances recommendations are made with a view to reducing the hazards in certain classes of these accidents.

Sep 1, 1931

By H. E. Hilliard

A method was investigated for detecting and counting filamentous iron bacteria in open recirculating cooling systems. It is simple and fast and does not require trained microbiologists. Samples from 26 systems were examined. Cells were cultivated on commercially prepared ready-to-use media. Cultures grew well on this medium and were identified as filamentous iron bacteria by microscopic examination and by their ability to deposit iron using the prussian blue reaction.

Jan 1, 1976

By R. W. Stahl

An award is a form of recognition given for superior performance in a special field of endeavor. Each year awards are given by the Joseph A. Holmes Safety Association and the National Safety Council to mineral industries&apos; mines, quarries, and plants that have worked a specific number of man-hours without a lost-time injury. These awards have a dual significance in that they prove that efficiency can be attained without injury to persons. Safety awards do not result from luck or good fortune but do result from sincere desire coupled with sufficient effort and cooperation to achieve a desired goal.

Jan 1, 1963

By R. B. Tippin

The heavy liquid separation (HLS) process was investigated by the Bureau of Mines to develop a means of concentrating minerals from natural ores, Various spodumene ores were tested in a 0.4-inch diameter cyclone using pure tetrabromoethane (TBE) as the heavy liquid. Studies were initiated to examine the influence of (1) pulp density (2) feed grade, (3) cyclone pressure, (4) cyclone apex opening size) (5) cyclone vortex finder opening sand (6) mineral particle size on the separation efficiency. Each of these factors was found to affect the heavy liquid separation in some degree; the mineral particle size exhibited the greatest effect and the ore feed grade the least. Conditions necessary to yield an 85 percent spodumene concentrate with an 85 percent recovery were determined to be: 70 psig pressure, 10 percent solids, 0.08-inch apex opening, 0.11-inch vortex finder opening and a minimum amount of minus 200-mesh fines in the feed. Operation of multiple cyclones in series resulted in spodumene concentrates assaying over 90 percent and indicated mineral recoveries exceed-in 90 percent.

Jan 1, 1967

By Oliver Bowles

"Conservation of slateWaste slate is a problem of outstanding importance in the slate industry, for a very large proportion of all slate quarried is thrown on the waste heap. While many uses for waste slate have been found, the demand calls for merely a fraction of the present supply of unused material. If the slate industry is to increase in prosperity, the producer's energy must be directed toward the development of ways and means of reducing waste to the lowest possible point. The Bureau of Mines of the Department of the Interior has devoted much study to this problem and a recent bulletin ** contains a detailed discussion of the waste problem.Attention has recently been directed toward an improved method of cutting slate in quarries, a method that promises to reduce greatly the percentage of waste material. The method has been introduced since that bulletin was published, and this supplementary paper covers the details of the process.A reversion in method,In connection with this new mode of operation history is repeating itself in a very interesting way, for the old quarry bar used years ago with steam drills, and later discarded in favor of the channeling machine .and the hammer drill, has been salvaged from the scrap heap, and again put to active use. The occasion for its employment is an attempt to improve quarry methods by the substitution of drilling for channeling or blasting."

Oct 1, 1923

By J. V. Scalera

Because of U.S. dependency on imported critical metals, the Bureau of Mines has conducted research to evaluate the possible substitution of nitrided low-alloy steels for higher chromium-containing alloys. The corrosion data for nitrided steels are limited primarily to the Soviet literature. The objective of this study was to determine the corrosion properties of six commercially nitrided low-alloy steels in a 5-wt % NaCl solution at pH 4. Weight-loss tests indicated that, in deaerated test solutions, most of the nitrided steels were less corrosion resist-ant than nontreated steels. However, electrochemical tests indicated that under more oxidizing conditions, nitrided materials are converted to a passive state with a significantly reduced corrosion rate. Elec-trochemical tests performed in an aerated environment confirmed the passivity of the samples in an oxidizing environment.

Jan 1, 1984

By R. H. Nafziger

The Bureau of Mines evaluated 18 domestic titaniferous materials with widely varying compositions, mineralogy, and physical properties in electric-arc furnaces, Techniques were devised to recover both the titanium and iron values contained in these materials so that the reliance of the United States on foreign sources of higher grade ilmenites and rutile might be decreased. Most of the tested titaniferous materials responded well to lower grade or byproduct reductants, such as bituminous coals, charcoal, and coke breeze. Sufficient slag fluidity was realized by maintaining from 8 to 12 wt-pct iron in the slags; no contaminating fluidizers were required. Fluid slags containing up to 79, 70, and 54 wt-pct Ti02 were realized from east coast ilmenites, a rock ilmenite, and a titaniferous magnetite ore, respectively. A carbon-lined furnace shell is recommended for minimum slag contamination. Good results also were obtained during extended submerged-arc furnace tests.

Jan 1, 1980

By R. G. Nelson

This report covers investigations of the Bureau of Mines for the period of June 15, 1952, to June 15, 1953, on a research project for the Materials Laboratory, Wright Patterson Air Force Base, Dayton, Ohio. The primary purpose of this investigation was to make high-purity chromium-base alloys having room-temperature ductility and high-temperature strength. The Nonferrous Metals Branch of the Bureau of Mines, Albany, Oreg., has, during the past 7 years, developed on a laboratory scale a hydrogen treatment method for making high-purity chromium that can be fabricated into thin sheet and wire. This material can be bent at room temperature. The object of this investigation was to use this material to develop improved chromium-rich alloys for high-temperature uses.

Jan 1, 1955

By George H. Holmes

The water situation in Nevada mineral and related industries is described in this report. It contains information on the sources and adequacy of supply to current operators, requirements and uses, quality and costs, geography, hydrography, precipitation and evaporation characteristics, and Nevada water laws. Also, information is given on the water requirements of one public utility powerplant, and the source and consumption of water in four major cities. Water distribution at 24 operations is shown on schematic waterflow diagrams. The mineral industries of Nevada in 1962 used 8.6 billion gallons of new&apos; water and reused 3.8 billion gallons for a total usage of 12.4 billion gallons. The copper industry was the major water user. The 1962 value of all mineral production in Nevada was $85.5 million. The large amount of water required to maintain thin high production is obtained principally from ground-water sources in alluvial valleys and the permeable rock formations of some mountain ranges. Some water is also obtained from perennial streams and springs. Sources of water utilized by existing industry ire near most mineral industry operations; however, seven companies are forced to pipe water distances ranging from 2 to 8 miles. Although water supplies of presently operating companies are adequate at most operations, several companies resort to large-scale reuse of water as a matter of conservation and economics. Acquisition of water by new operators is possible but takes considerable negotiation. Water rights, surface and underground, are controlled by the State. The quality of the water is satisfactory for most purposes. Analyses of 19 samples, listed in the appendix, show the range in water quality at various plants throughout the State. Costs of delivering new water to current operations range from 2 to 26 cents per 1,000 gallons with an average of 10 cents per 1,000 gallons for power and maintenance. No firm costs for recirculating water were available; estimated costs range from 1.5 to 2.5 cents per 1,000 gallons. The mineral-product value of the entire Nevada mineral industry in 1962 was equivalent to $10 per 1,000 gallons of new water and $26 per 1,000 gallons consumed. Projection of the 1962 water requirements of the Nevada mineral industry indicates that the demand For new water will increase from 8.6 billion gallons in 1962 to 11.9 billion gallons in 1980, a 43-percent increase. Water requirements in the year 2000 are estimated as 14.8 billion gallons, an increase over 1962 water demand of 78-percent.

Jan 1, 1966

By Martin H. Stanczyk

The Bureau of Mines studied continuous closed-circuit attrition grinding of a coarse commercial filler-grade kaolin to produce paper-coating-grade clay having a particle size analysis of at least 70 percent minus 2-micron equivalent spherical diameter (esd). The coarse clay, containing about 12 percent minus 2-micron-esd material, was ground in a Bureau-developed 10-inch-diameter attrition grinder in closed circuit with a 5-foot-diameter bowl classifier. In the best test, a finished product containing 82.7 percent minus 2-micron-esd material was obtained when grinding 20 pounds of raw clay per hour at percent solids with a 100-percent circulating load. Energy consumption was about 341 kilowatt-hours per ton of clay feed, or 487 kilowatt-hours per ton of minus 2-micron-esd material produced. Closed-circuit grinding gave some-what greater particle size reduction and lower energy consumption than either batch or continuous open-circuit grinding.

Jan 1, 1965