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By J. L. Reuss

The Bureau of Mines investigated the technical feasibility of smelting copper concentrates containing chalcocite (Cu2S) and native copper using nonpyritic sulfur-bearing materials to aid matte formation. The procedure consisted of combining various proportions of commercial chalcocite concentrate, smelter slag, fluxes, and matte-forming constituents to produce charges of comparable compositions. The mixtures were charged in fire-clay crucibles and smelted in an induction furnace at 1,300° C. The research proved that either sulfur or gypsum can replace pyrite as a matte-forming material, and that gypsum produces an exceptionally high-grade copper matte. The addition of small quantities of metallic iron to the nonpyritic smelting charge furthers the removal of sulfur, improves the recovery of copper, and makes it possible to utilize gypsum as the exclusive flux and matte-forming ingredient, thereby eliminating the necessity of adding limestone.

Jan 1, 1968

By R. F. Waters

Laboratory-scale selective volatilization methods developed by the Bureau of Mines to recover germanium and gallium concentrates from coal fly ash and phosphorus furnace flue dust are summarized. In the better experiments between 85 and 98 percent of the germanium was recovered as the lower oxide and as sulfides, and between 75 and 97 percent of the gallium was recovered as the lower oxide and as the trichloride. Grades of the condensates were inconsistent and varied between a few tenths of a percent and 8 percent, depending on the method used. In the primary extractions of germanium alone the degree of enrichment surpassed 100 to 1, and for gallium the best ratio was 30 to 1. Upgrading of condensates by vaporization retreatment and by leaching and precipitation is discussed. An appreciable degree of mechanical preconcentration by attrition scrubbing and elutriation was possible on two fly ash samples.

Jan 1, 1967

By Wallace W. Key

Mineral raw materials produced in California, other States, and foreign countries were purchased for consumption in quantities valued at over $60 million at 800 of the 1,200 chemical plants operating in California in 1960, according to questionnaires completed by company officials. These and other data received from mineral consumers, producers, dealers, and Government agencies formed the basis for this the first of a series of reports designed to present the intricate features and relationships controlling mineral raw material supply and demand in California industries. The results of this study indicated certain changes in use patterns of minerals in chemica 1 manufacturing; a shift in requirements from metals to nonmeta ls, from inorganics to organics, from natura 1 to synthet ic materia ls , and from distant to local sources of supply.

Jan 1, 1965

By T. A. Evans

The Bureau of Mines conducted a Laboratory and pilot-plant investigation of the flotation of iron sulfides from zinc-lead mill tailings near Platteville, in south-western Wisconsin, at the North Central Experiment Station, Minneapolis, Minn. The procedures used and the results obtained in this investigation are described in this report. Samples for laboratory tests were obtained from each mill in the district, namely, Calumet & Hecla, Inc., Eagle-Picher Co., Vinegar Hill Zinc Co., and Tri-State Zinc, Inc. The sample fat pilot-plant work was obtained from the Davis Mining Enterprises mill.

Jan 1, 1957

By Bruce Cantrell, K. L. Rubow

"INTRODOCTIONMeasurement of the contribution of diesel exhaust to respirable aerosol in mine environments has become increasingly important because of current concerns over the occupational health effects resulting from exposure to diesel emissions. In response to this, the U.S. Bureau of Mines is developing and evaluating new sampling methods for measuring diesel aerosol in underground mines. Two such techniques are being studied by the Bureau, size selective sampling and Chemical Mass Balance (CMB) modeling. These techniques use measurable physical or chemical characteristics of a mine aerosol sample to infer the amount of diesel particulate material contained in the sample.Size selective sampling is being adapted for measurement of diesel aerosol by the Particle Technology Laboratory (PTL) of the University of Minnesota under sponsorship by the Bureau. 1 It is based on the premise that diesel and mineral dust aerosol can be physically separated by size and collected during sampling using inertial impaction. An independent effort by the National Institute for Occupational Safety and Health to develop a size selective sampling technique was also sponsored by the Bureau.The second technique, CMB modeling, is being developed by the Bureau as an alternative measurement technique to referee the results obtained using size selective sampling.3 It compares measured trace element ""finger prints"" of aerosol sources with similar profiles of mine aerosol samples. From these, the portions of the sample contributed by each source can be determined. Results of these investigations in underground coal mines have confirmed that diesel and coal dust aerosol are of different size and can be measured separately using size selective sampling techniques.A major difference in diesel usage among underground mines is the requirement for exhaust gas cooling systems in coal and gassy noncoal mines. Nongassy mines usually employ limited exhaust conditioning in the form of catalytic converters, which have limited effect on primary exhaust particulate. The cooling system in most general use in gassy mines is the water scrubber. This device has little effect on most of the gases but removes particulate material from the exhaust. 5 Because of this, exhaust aerosol characteristics in nongassy mines are expected to be different. To see if size selective sampling techniques can be used in such mines, the Bureau and the University of Minnesota conducted a second study in three metal and nonmetal mines, two nongassy and one rated as gassy."

Jan 1, 1990

By M. C. Malamphy

The report of work accomplished on the United States Bureau of Mines' bauxite project in Pulaski and Saline Counties, Ark., is presented in this volume and in a series of Reports of Investigations immediately following this volume. This first volume covers the project as a whole, whereas the subsequent volumes contain maps of local areas and deposits developed, together with logs of the drill holes and descriptions of the separate deposits. The Arkansas bauxite project was initiated in December 1941 and continued for 4 years. The first 5 months were spent in studying the problems presented and in geophysical exploration, Core drilling began in May 1942 and ended in May 1945. The project was one of the larger and more important of those undertaken by the Bureau of Mines for the purpose of developing domestic sources of supply of critical and strategic minerals necessary for National defense and for the successful waging of modern mechanized warfare. Some of the results of the Bureau's bauxite exploratory work have been made available to the public through the medium of press releases, transactions of technical societies, and government publications. More information has been supplied to government agencies upon request and to land owners and mine operators of the deposits concerned in the form of maps showing locations of all holes drilled on the property and logs with chemical analyses of' all cores recovered. In October 1946, the factual data were made avail-able to .the public in manuscript form in an-"open file" at the office of the State geologist, R. B. Foxhall, Little Rock, Ark., and at the office of the. Bureau of Mines in Washington. For the purpose of providing a background for the presentation of the factual data obtained, the history of bauxite is reviewed briefly. Information relative to past production and reserves of bauxite in Arkansas also is given. A resume of the development of the industry in Arkansas, the exploration and mining methods employed, the various uses to which the bauxite is put, and a brief outline of the geology of bauxite in Arkansas complete the -background.

Jan 1, 1948

By Charles S. Allbright

To develop a method for predicting the stability of a fuel during long-term storage from rapid aging tests at 200° F, the Bureau of Mines determined the stabilities of three gasoline base stocks and an alkylate blending stock in both sealed storage and aerated storage at 110° F for periods extending to 32 weeks. Stabilities of samples containing gasoline-additive compounds were compared by aging, using two methods--rapid aging in a bomb at 200° F for intervals up to 16 hours and storage at 110° F. The additives used were an uninhibited tetraethyllead motor mix, N,N'-di-sec-buty1-p-phenylenediamine and 2,6-di-tert-butyl-4-methylpheno1. Results were related by graphs that enable predictions of gum and sediment formation during storage from data obtained in bomb tests. A premium-gasoline base stock and the alkylate proved to be stable, but the two regular-grade gasoline base stocks were found to be unstable. Addition of the diamine antioxidant improved the stability of both of the regular gasoline base stocks, while the phenol antioxidant improved only one of them. The presence of the tetraethyllead decreased the storage stability of all four fuels, both with respect to formation of gum and precipitation of inorganic sediment. The rapid test at 200° F appears to offer promise as a basis for a method of predicting gasoline stability in long-term 110° F storage.

Jan 1, 1968

By C. W. Owings

Available literature published or abstracted in 1953 and 1954 relating to dust prevention and suppression has been summarized and reviewed in this report, and un-published information also is included to outline current practice for those interested in dust control in and around mines, tunnels, and quarries. More and more companies are realizing the value of controlling dust by incorporating suitable methods and devices in the planning stage. In preparation and crushing plants preliminary tests have been made of the fine materials to determine the best type of dust-control equipment to use, and the details of the quantities of air, the number of sprays, the dust-allaying fluids, and the location of hoods or enclosures have been determined in advance. Such planning has paid for itself in more effective control. Similar planning in a tunnel resulted in healthful conditions and low dust concentrations.

Jan 1, 1956

By J. W. Town

Studies were made by the Bureau of Mines to determine the influence of textural features on the beneficiation of phosphate minerals (pellets) from selected bed and composite samples representing different rock types of the Western Phosphoria Formation. The particle size of the samples was reduced by attrition grinding to minus 20-, 28-, or 48-mesh depending on ore grade and gangue matrix. Sizing of the ground material showed that the phosphate pellets would concentrate in the plus 200-, 270-, or 325-mesh size fractions sufficiently so that the phosphate content was above the 31.5 :cent P2O5 required for acidulation. The phosphate content of essentially pure phosphate pellets was shown to range from 33 to 39 percent P2O5. Microscopic identification of the particles in each size fraction showed that the phosphate was either in the pellet form and readily liberated or so intimately associated with the gangue matrix that size reduction necessary Co obtain liberation was impractical.

Jan 1, 1967

By N. O. Johnson

This is one of a series of-Information Circulars dealing with mining and milling methods and costs at mines in various districts in the United States. The Hog Mountain gold mining district is of the northern edge of Tallapoosa County, in the east central part of the State of Alabama. The district is equally close to Goodwater and to Alexander City, both stations on the main line of the Central of Georgia Railroad. From Alexander City the mine is reached by 13 miles of graded road, traveling in a northeast direction. In dry seasons the road is good; in wet weather it is bad but passable. Improvements are being made constantly on the road, so that in the near future the gravel road should be good under all weathered conditions.

Jan 1, 1936

This information circular describes research the Bureau of fines has conducted to improve technology for recovering precious metals from low-grade resources. Many of the reported findings are recent, and some of the work described is ongoing. Topics discussed include cyanidation of carbonaceous gold ores to enhance gold recovery, a new method for precipitating mercury during cyanide leaching of gold ores, a staged heap leaching process to generate suitable solutions for direct electrowinning of gold, the use of anion-exchange resins to recover gold from cyanide solutions, and precious metals recovery from electronic scrap.

Jan 1, 1986

By H. W. Kilau

The U.S. Bureau of Mines is evaluating water spray additives for the purpose of improving respirable dust control during coal mining operations, with particular emphasis on the longwall shearer. Recent field tests of surfactant-polymer reagents at two production longwall operations have shown favorable respirable dust reductions compared with water sprays containing no additive. Gravimetric dust samples obtained by a technician downwind of the shearer while following or preceding the machine showed dust reductions in the range of about 40% to 60% for some of the reagent formulations compared with using water alone. Three polymers were tested: two polyethylene oxide compounds of different molecular weight and hydroxypropyl methylcellulose (HPMC). All were effective for dust reduction, and two were cost effective when used in combination with sodium di(2-ethylhexyl) sulfosuccinate surfactant. How-ever, the use of these reagents requires the longwall operator to be more aware of headgate dust control. Experimental evidence indicates that dust captured by reagent-treated sprays at the shearer can be reemitted in the headgate area if stagcloader-crusher sprays and other dust controls are inadequate.

Jan 1, 2010

By S. L. Weber, Y. H. Cheng, D. E. Banks, J. K. H. Ma

"The aggressive industrialization of America, the development of powered tools which generated massive amounts of respirable-sized dust particles, a latency period which may mask the relationship between exposure and development of disease, inadequate (or perhaps even careless) understanding of the relationship between dust exposure and disease, and respiratory protection which has later proven to be inadequate have resulted in a series of epidemics of silicosis which have caused the premature death of many workers.1-11 Emphasis on the regulatory control of dust levels in the workplace has greatly reduced the development of pneumoconiosis in the United States and in other developed as well as underdeveloped countries, yet the prevention of silicosis or coal workers' pneumoconiosis has not come close to being accomplished. Despite the public health perspective that pneumoconiosis arc totally preventable illnesses, there appears to be little evidence that this is the case.Cases of pneumoconiosis continue despite aggressive enforcement policies by regulatory agencies, attempts at dissemination of very readable materials aimed at workers and management 12.13 and respiratory dust exposure standards which are in place and appear, for the most part, protectivc.14- 16 It is more than frustrating for all parties associated with advocating workers' health to see reports of workers with aggressive silicosis. On another level, both the physician and the affected worker are helpless when a diagnosis of silicosis or coal workers' pneumoconiosis is made. Both realize that there is no proven way to affect the natural history of these progressive inflammatory and fibrotic processes. Neither is there any ""compassionate use"" therapy. What must be developed, at the very least, is a ""salvage therapy"" which has the potential to reverse, or at least dramatically lessen, the aggressive natural history of silicosis which develops over relatively short time periods. Because of the aggressive nature of silicosis (compared to coal workers' pneumoconiosis) attempting to develop a therapy for this illness should be a priority."

Nov 1, 1995

By L. J. Kane

Applications are described of various methods for determining the weight concentration and physical properties of solid and liquid impurities of gases in connection with problems encountered in synthesis-gas production. Of special interest among these methods may be listed: 1. A method developed for determining, the weight concentration of solid and liquid impurities in. hot, crude synthesis gas containing a high concentration of moisture. 2. A method developed for the same purpose but for highly purified synthesis gas or atmospheric air. 3. A method for obtaining a uniform dispersion of dry duet or, a microscope slide for particle-size determination or other purposes.

Jan 1, 1954

By Horace C. Porter, F. K. OVITZ

The various fuel investigations that were being carried on by the technologic branch of the United States Geological Survey were transferred by law on July 1, 1910, to a new federal bureau, the Bureau of Mines, that was authorized to continue the investigations and make public reports of the results. In consequence of this transfer, the following report is published as a bulletin of the new bureau. The United States Geological Survey had been engaged in analyzing and testing coals, lignites, and other mineral fuel substances under authority given by act of Congress. This work, now centered at the experiment station at Pittsburg, Pa., had its beginning in the operations of the coal-testing plant erected at the Louisiana Purchase Exposition in St. Louis, Mo., in 1904. The results obtained at that plant showed that the work of determining the fuel value of the coals and lignites in the United States with a view to increasing efficiency in their utilization would be incomplete if it did not include systematic physical and chemical researches into the processes of combustion. Hence in its later investigations the Survey carried on such re- searches, concentrating attention on those lines of inquiry which promised results of greatest economic importance. This bulletin is a report on an investigation of the volatile matter in several typical coals-its composition and amount at different tem- peratures of volatilization. As the investigation is still in progress and will doubtless include other coals than those already examined, the bulletin may be considered a preliminary report, stating the prob- lems studied, the methods used, and the results thus far obtained.

Jan 1, 1910

By N. C. Dunham

"The Bureau of Mines exploratory work on the Bear Lodge, Wyo., fluorite property wider the strategic minerals Program was completed in November 1944. Exploration consisted of surface trenching, shaft sinking, and drifting at shallow depth. Doak C. Cox of the Federal Geological Survey visited the area during the latter part of 1944 and napped the Bear Lodge property.The Bear Lodge property is situated in the Black Hilts National Forest in eastern Crook County, Wyo., 6 miles north of the community of Sundance (fig. 1). Sundance is 29 miles northwest of Upton, Wyo., a station on the Chicago, Burlington, & Quincy Railroad and 43 miles southwest of a siding on the Chicago & Northwestern Railroad, 3 miles south of Belle Fourche, S. Dak. U. S. Highway 14 passes through Sundance in an east-west direction. Sundance may be reached from the south over U. S. Highway 85 and Wyoming State Highway 585.The Bear Lodge property i a situated in the Boer Lodge Mountains in secs. 15, 22, and 23, T. 52 N., R. 63W., 6th P.M.The topography in the vicinity of the fluorite deposits consists essentially of rounded hills which slope gently to the valley floors. Near the north end of the Property the terrain steepens locally, and the canyon walls are Precipitous along the courses of several streams. There is an adequate supply of water and native timber for mining purposes. The average elevation near the deposits is 5,700 feet.The climate of the region is relatively moderate. The summers are usually warm, with frequent rainstorms. Temperatures often fall below zero during the winter months. Snowfalls are moderate to heavy.Fluorite occurrences in the Bear Lodge area have been known since 1914; however, fluorite was not discovered on the Bear Lodge property until 1943, when prospectors working on a nearby manganese deposit found fluorite mineralization in the limestone. No production has been recorded from the property."

Apr 1, 1946

By Robert H. Peters

Several significant problems associated with employee turnover among underground miners are described in this Bureau of Mines report. Although a vast amount of research has been conducted on turnover among employees in nonmining industries, there has never been an attempt to empirically investigate the causes of turnover among underground miners. This report presents the results of empirical research on employee turnover in other industries and describes and critiques the research methods that have been used to investigate turnover. Using the findings on employee turnover in other industries and known data about miners and the mining industry, a conceptual model of the factors that cause turnover among miners was generated. This model, which is expected to provide a basis for later empirical studies, is presented. Several recommendations for controlling miner turnover are also presented.

Jan 1, 1986

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

The panic bars (and associated linkage's and electrical circuitry) that are defined in this document are a machine operator-actuated control for the emergency deenergization of the tram motors on Self-propelled, electric and diesel face equipment; including haulage equipment such as shuttle cars. There are nine basic types of panic bars (and several variations) that are recommended in this document, but all of the panic bars are characteristically of the "fire door" type that is frequently encountered on outside exit doors of many public and soma commercial buildings. It is also the intent of the following panic bar designs that, when emergency brakes are added to the face equipment machinery for which they are required, that they be designed and hooked up so that actuation of the panic bar will result in automatic application of the emergency brakes (immediately following the deenergization of the tram motors). The following panic bar design requirements are a restatement of the proposed requirements defined in the Federal Register, requirements cited in 'Guidelines for the Design and Installation of Devices for Deenergization of Self-Propelled Electric Face Equipment/Automatic Emergency Brakes" by C. E. Lester and J. D. Greenhalgh of MESA, and Bendix recommendations that were formulated as a result of discussions with personnel at the various machine manufacturers and underground coal mines that we surveyed, discussions with G. L. Judy (our consultant), etc:

Jan 1, 1974

By E. J. Gleim

[THE ORGANIC act under which Federal Bureau of Mines was established provided for the investigation of the safe use of electricity in mines. Each Congress appropriates funds for conducting this investigation. As part of this investigation, electrical apparatus used in mines is studied to determine if its operation and use might introduce a hazard. From this study, certain safety standards have been developed. These standards, established with the aid of both the manufacturer and user of such apparatus, are published in schedules, and apparatus that complies with the requirements set forth these schedules is classified as "permissible." This term is defined to designate apparatus as "completely assembled and conforming in every respect with the design formally approved by the Bureau of Mines." In the judgment of the Bureau, the manufacturers of such apparatus have adhered to certain minimum standards of safety in supplying a product that when properly used and maintained is safe for operation in mines where flammable gas or coal dust may accumulate. This work of the Bureau of Mines for increasing safety does not make it obligatory for manufacturers of mine equipment to produce only that of permissible classification. Before the effective date of the Federal Mine Safety Code,5 the Bureau sought to promote safety by recommending that mine operators install permissible equipment in gassy mines as a preventive measure against gas and dust explosions initiated by electrical equipment. For some years, the mining laws of several States have prescribed the conditions under which permissible equipment must be used. The Federal Mine Safety Code requires that ?all new electric face equipment and replacements of equipment purchased for mines where nonpermissible equipment is now being used shall be of a permissible type approved by the United States Bureau of Mines,]

Jan 1, 1955