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By Hillary W. St. Clair

This report gives the results of an experimental study of the progressive changes that occur in particle size and size distribution when a homogeneous and isotropic mineral is subjected to crushing by impact. The mineral used in the study was uniformly sized quartz, which was crushed in a simple drop¬-weight machine that applied impact energy up to about 100 kg-cm per g. Screen analyses of the crushed products were analyzed by the method of moments to determine the mean size, variance, skewness, and kurtosis. Analysis of the data from these experiments shows that the mean size of the crushed product is a function of the energy input and the initial size. The size distribution is functionally related to the degree of size reduction. As the mean particle size is decreased, at first there is a corresponding increase in the variance and decrease in the skewness, But, as size reduction is carried further, each tends eventually to approach a steady value, and the form of the size distribution becomes stable.

Jan 1, 1972

By Charles E. Whieldon, C. I. Pierce

Data on the oilfields in Mahoning , Columbiana , Carroll , Jefferson , and Harrison Counties , Ohio , were collected from scattered sources and compiled to make the information readily available to operators who may be interested in conducting secondary - recovery operations in the area . General geology , oil production , oil - productive acreage , core data , reservoir calculations by townships , and miscellaneous data and reference material are presented .

Jan 1, 1965

By E. S. Shedd

The Bureau of Mines investigated electrowinning and tapping lanthanum metal from lanthanum oxide in a fluoride bath. The electrolyte was composed of LaF3, BaF2, and LiF. Metal containing 0.2 percent impurities was produced at a rate of over 2 pounds per hour. Principal impurities were carbon, aluminum, and silicon. Low-carbon metal was produced by continually discharging the carbon oxide gases and maintaining 0.1-atmosphere pressure. Anode reactions and cell design were found to be important factors in cell operation. Both frozen electrolyte skulls and tungsten metal crucibles proved satisfactory for collecting the metal and did not react with the molten lanthanum.

Jan 1, 1966

By H. E. Powell, T. E. Hill, W. A. Calhoun

The object of this investigation was to determine the effectiveness of certain cationic flotation collectors , Ethomeens , in recovering fine particles of lead minerals from mill tailings at a grade equal , at least , to that of the mill feed ( 1.7 percent lead ) . The Ethomeens , derived from tertiary amines having one fatty alkyl group and two polyoxyethylene groups attached to the nitrogen , were evaluated by bench- scale flotation tests . The 14 Ethomeens tested consisted of four groups : Coco amine , soybean amine , tallow amine , and stearyl amine . The best results were obtained with coco amine C / 12 , soybean amine S/ 15 , tallow amine T / 12 , and stearyl amine 18/20 . From a feed containing 0.23 percent lead , rougher concentrate grades of 2.12 to 3.89 percent lead were obtained , with recoveries of 17.3 to 27.5 percent of the total lead . Some of the lead mineral particles recovered had diameters of less than 1 micron . In comparative tests , the Ethomeens , or polyethoxylated amine types of cationic surface active agents , were more selective than conventional xanthate collectors for flotation of slimed lead minerals .

Jan 1, 1964

By S. H. Ash

The paramount responsibility of Government is to protect the general welfare. One of the chief functions of the Bureau of Mines is to investigate and publicize methods of increasing safety and efficiency in mining operations. In an industrial civilization, energy resources constitute the foundation of a sound economic structure (14).4/ Coal is only one source of energy, but it provides more than half the energy consumed in the United States.

Jan 1, 1946

By R. E. Tremoureux

This paper describing the methods and costs of quarrying limestone at Sloan, Nev., is one of a series of similar papers being prepared for and published by the Bureau of Mines on this industry in the United States. These papers are designed to disseminate information regarding the methods used. The cost tabulations represent local operating expenditures only and not total production costs. It is recognized that publication of total production costs might in many instances cause embarrassment to individual producers as well as to the industry as a whole. On the other hand, operating costs are essential to the technical discussion and study of the methods Employed. The attention of the reader is specifically called to this differentiation in order that no misunderstanding of the scope of the cost tabulations shall ensue. The quarrying operations at Sloan are interesting not only from a technical viewpoint and because of the magnitude of the deposit, but also because the quarry is located in a desert region far removed from the centers of population where lime is used. The quarry and plant are in Clark County, Nev., 20 miles west of Las Vegas, which is the nearest town to the site of the Boulder Canyon Dam. Sloan is on the main line of the Union Pacific Railroad connecting Salt Lke City and Los Angeles. The latter city is 280 miles from Sloan and it is the shipping, point for all supplies.

Jan 1, 1932

By F. S. Crawford

Interesting data on electric blasting and sinking of the Montreal No. 5 shaft of the Montreal Mining Co., Montreal, Wis., were obtained during the sinking of the last 877 feet of this shaft. Several unusual features and safety practices are also to be found in the Montreal mine. The Montreal shaft was sunk 2,156 feet from August 16, 1921, to May 1, 1924, and 877 feet from October, 1927, to June, 1928. The first section of the shaft was supported with steel sets spaced 5 feet on centers; and instead of lagging the walls were covered with three-eighths of an inch of gunite where Greenstone was encountered, and where quartz-slate was found (from the surface to the 12th level) the walls were lagged with tamarack lath treated with carbolineum, a preservative.

Jan 1, 1929

By Joseph A. Conway

This paper is one of a series dealing with the mining and crushing methods and costs of the nonmetallic industries, prepared under the sponsorship of and in cooperation with the U. S. Bureau of Mines,. The quarrying methods described in this paper are those used at the Monocacy trap rock quarry which annually produces from 450,000 to 500,000 tons of crushed stone. This property is located 3 miles east of Birdsboro at Monacacy, Pa., and is one of the three quarries operated by the John T. Dyer Quarry Co. Throughout the paper an effort is made to explain the various methods used and the cost of operation.

Jan 1, 1931

By E. R. Cole

This Bureau of Mines investigation was prompted by the need forr a stable anode for electrowinning metals, particularly zinc and copper, from acid solutions. The polarization behavior of Pb-Ag (1 pct Ag) anodes in H2SO4 and fluoride solutions was determined as the first step in the development of such an anode. A Luggin capillary, dc power supply, high-impedance voltmeter, and other equipment standard to an electrochemical laboratory were used in this study. It was determined that during polarization, a relatively hard, stable coating of Pb02 was formed on the surface of the lead-silver anode and the rate of formation of this coating was considerably enhanced by the presence of fluoride ions in solution. Subsequent investigations at the Bureau of Mines Rolla Research Center resulted in the development of a Pb02-coated titanium (Pb02-Ti) anode. Results of this effort were presented in Bureau of Mines Report of Investigations 8111. Additional data resulting from extensive testing of the Pb02-Ti anodes, as well as process improvements and innovations, are included in this report. The anodes were considered generally unsatisfactory for zinc electrowinning because of lower conductivity, higher oxygen overvoltages, and shorter in-cell life as compared with the Pb-Ag anodes now being used in industry. However, the PbO2-Ti anodes were used successfully to oxidize waste chromium solutions and to electrowin copper.

Jan 1, 1981

By J. R. Hauger, P. A. Romans, W. J. Niebuhr

With suitable instrumentation and techniques it is possible to determine the presence of tantalum in columbium to 20 ppm . This paper discusses the selection of X- ray spectrographic instrumentation and describes a technique for accomplishing the low level determination of tantalum . An ion- exchange method of separating tantalum from columbium is also described .

Jan 1, 1964

By Kathleen M. PH. D. Kowalski

This paper discusses human judgment and decision-making under stress. The authors review selected recent literature across various disciplines and suggest a definition of stress within the context of decision-making during the management of emergencies. They also discuss fieldwork by the Pittsburgh Research Laboratory, NIOSH, which explores traumatic incident stress, the relationship between previous training and performance under stressful conditions, and human behavior in underground mine fires. The authors assert that stress is one of the factors that decision-makers must contend with in most life-or-death situations. They suggest that a better understanding of individual's judgment and decision-making activities while under stress would yield a better understanding of how people reach the choices they make in emergencies. This enhanced understanding would be of enormous value to emergency managers, researchers, and policymakers.

Jan 1, 2008

By E. V. Cilento, K. A. DiGregorio, R. C. Lantz

"An electro-optical method was used to quantify superoxide (SO) release from single rat pulmonary alveolar macrophages (PAM) exposed in vitro to respirable quartz and kaolin dusts and in vivo to quartz. Release was determined by measuring the reduction of nitroblue tdrazolium (NBT) to a diformazan precipitate at 550 nm from video-recorded images of individual cells. In vitro exposure to 0.025 or 0.05 mg/ml kaolin for 40 minutes resulted in no significant differences in either the total diformazan produced (max) or the maximum rate of diformazan production (R)./n vitro exposure to 0.025 mg/ml c1uartz decreased max 38 percent while no significant change was found using 0.05 mg/ml. However, R was decreased 31 percent and 24 percent for the low and high dose, respectively. In contrast, PAM obtained from animals exposed in vivo to quartz dust for two or four weeks in inhalation chambers exhibited increased production of diformazan. However, only PAM analyzed three days post-exposure showed significant increases, while PAM from animals sacrificed ten or 31 days post-exposure were not significantly different from control. The combined in vitro and in vivo quartz results might suggest that there is an initital acute response to exposure that decreases the ability of PAM to produce SO, followed by recruitment of production of PAM with increased SO producing capability. It appears that removal of animals from the source of exposure permits PAM to return to control levels of SO production by31 days. Whether this would be true for chronic exposure remains to be elucidated.IntroductionPulmonary alveolar macrophages (PAM) protect the lungs by phagocytizing foreign debris and bacteria.(1) This process involves ingestion as well as destruction of foreign matter. Phagocytosis usually is accompanied by a respiratory burst which increases cellular oxygen consumption leading to the release of highly reactive oxygen metabolites.(2) These agents have been implicated in the killing of bacteria by phagocytes, but they have also been shown to be toxic and,have been linked to cancer, emphysema, arthritis, diabetes, and other diseases.(3) Toxic effects may be a result of 1) an abnormally low production of metabolites, resulting in damage to lung tissue by the respired bacteria and/or dusts; or 2) an abnormally high production resulting in direct damage to lung tissue by metabolites themselves."

Mar 1, 1989

By T. H. Jeffers

To help maintain an adequate supply of minerals to meet national, economic, and strategic needs, the Bureau of Mines investigated the feasibility of extracting copper from coarse native copper ore with ammoniacal ammonium carbonate solution by a simulated in situ leaching procedure. A 5.9-metric-ton (6.5-ton) sample of minus 30.5-centimeter (12-inch) conglomerate-type ore analyzing 1.96 percent copper was leached in a column for 556 days with a solu-tion that contained, in grams per liter, 2.2 NBs and 1.9 CO[3=]. The copper extraction was 71.4 percent, and reagent consumptions were, in kilograms per metric ton of ore, 1.1 NBs and 0.85 CO[3=] (in pounds per ton of ore, 2.2 NH3 and 1.7 CO[3=]). The pregnant leach solutions contained about 1.4 grams per liter copper, which was readily extracted from these low-tenor liquors with a 1:19 mixture of an organic extractant and kerosine. Copper was stripped from the loaded organic with depleted electrolyte containing 150 grams per liter H2S04, and the copper was recovered by electrowinning with antimonial lead anodes. Conditions also were established for minimal lead transfer to the cathode copper.

Jan 1, 1979

By Thomas L. Vandergrift

This U. S. Bureau of Mines (USBM) report evaluates three stress-transfer-modification concepts for their potential in reducing longwall gate road stresses and closures. In each of the three concepts - packwalling, gob infilling, and entry filling -support structures are constructed on the headgate side of the panel parallel with or inby the face line. When the headgate becomes the tailgate of the adjacent panel, these structures are in place to accept stresses transferred from the mined-out panel. Using the USBM nonlinear boundary-element program MULSIM/NL, baseline models of typical longwall stress transfer behavior were developed for both intermediate depth and deep mining conditions. These models were verified by comparing model results with field measurements and observations. The stress-transfer-modification concepts were then incorporated into the deep baseline model to quantify the effects of each concept on tailgate closure. Modeling results indicated that entry filling is the most effective concept in reducing tailgate escapeway closure. Using only 18 m3 of a weak fill per meter of face advance (7.3 yd3 per ft of face advance), tailgate escapeway closure was reduced by 33%. By improving the quality of the fill, similar results were achieved using 50% less volume.

Jan 1, 2010

By Katherine Harding

Basic concepts of matrix algebra and manipulations of matrices are presented in such a way that little competence in mathematics is required. Examples are always included to illustrate concepts and techniques. The paper is divided into six sections. The first four sections are devoted to some of the more basic concepts of matrix algebra, whereas the last two sections are concerned with specific applications.

Jan 1, 1967

By W. L. Schmidt

The effect of a water-repellent film in sandstone cores on the effective permeability-saturation relationship was investigated as part of a cooperative research program between the Bureau of Mines and the American Gas Association. The repellent film was formed by the reaction of methyltrichlorosilane3 with the connate water in the core. Other researchers have reported on the use of silicone chemicals to alter the flow characteristics of porous media (1-3, 5-7, 9, 10).4 The previous studies, however, dealt almost entirely with oil-water or oil-gas systems and not with water-gas systems. The primary purpose of this study was to determine the feasibility of using silane to retard the influx of water into natural-gas storage wells and to determine the necessary requirements for achieving this result. The success or failure of silane treatment as a remedial measure depends on its effect on gas-production rate and attendant water production.

Jan 1, 1961

By James P. Bennett

In this Bureau of Mines study, portions of four acidproof bricks (two red shale and two fireclay) were exposed to 20 wt pct RCI at 900 C for periods of 30 days. Three different techniques were selected to deter-mine volume expansion of these materials after exposure. Linear expansions ranging from about 0.02 to 0.12 pct were noted from Ta pin and dilatometer measurements. The use of strain gages to measure expansions was not successful. The red shale and fireclay brick with the lowest apparent porosities had the lowest expansions. Expansion data obtained by direct measurement of samples exposed for 30-day periods or by dilatometric measurement of autoclaved samples ex-posed for 2 h were comparable. This suggests the use of an accelerated autoclave exposure procedure for determining volume expansion effects of ceramic materials in acid environments.

Jan 1, 1985

By Ronald D. Hill, Elmore C. Grim

The removal of overburden often exposes pyritic materials (iron disulfide). As shown in equations 1 and 2, the oxidation of this material results in the production of ferrous iron and sulfuric acid. The reaction then proceeds to form ferric hydroxide and more acid, as shown in equations 2 and 4. [ ] Consequently a low pH water is produced (pH 2-4.5). At these pH levels, the heavy metals such as iron, manganese, copper, and zinc are more soluble and enter into the solution to further pollute the water. Water of this type supports only limited water flora, such as acid-tolerant molds and algae; it will not support fish life, destroys and corrodes metal piers, culverts, barges, etc., increases the cost of water treatment for power plants and municipal water supplies, and leaves the water unacceptable for recreational uses. The amount, and rate of acid formation, and the quality of water discharged are a function of the amount and type of pyrite in the overburden and coal, time of exposure, characteristics of the overburden, and amount of available water(l). Crystalline forms of pyritic material are less subject to weathering and oxidation than amorphic forms. Since oxidation by oxygen is the primary reaction during early acid formation, the less time pyritic material is exposed to air, the less acid is formed. Thus, a positive preventative method is to cover pyritic materials as soon as possible with earth, which serves as an oxygen barrier. In terms of mining, this step is accomplished by current reclamation techniques and small open pits.

Jan 1, 1974

By Sara J. Davenport

Hydrogen sulfite has been listed (1)3/ as a possible hazard in 50 occupations, many of which are in the mineral industries. The effects of its occurrence in the petroleum industry made themselves felt more than two decades ago, resulting in a comprehensive study (2) of the toxic gases from Mexican and other high-sulfur petroleum products. The mining industry, likewise, has had cause to guard against this gas. Enough hydrogen sulfide has been found in coal and some noncoal mines during normal operations to cause severe eye irritation, some serious illness, end even fatalities. It is usually a product of the decomposition of sulfur compounds and may be produced by burning explosives containing sulfur; the gas in harmful qauntities is formed by the use of block blasting powder or by the use of dynamite in blasting sulfide ores. Hydrogen sulfide is readily soluble in water, and enough may be released from water streams in coal and noncoal mining to cause fatal poisoning it is found sometimes in stagnant water underground, particularly where ventilation currents are absent, and great care must be exercised when accumulations of such waters are disturbed, as exposure to comparatively low concentrations of the gas evolved therefrom has caused fatal accidents.

Jan 1, 1945

By K. K. Kelley, L. B. Pankratz

The heat contents of four silicate minerals -- akermanite , cordierite , gehlenite , and merwinite --were measured from 298 ° to around 1,700 ° K by the dropping method . The results were compiled into tabular and equation forms suitable for thermodynamic calculations . The heat contents of these compounds are nearly additive with respect to their constituent oxides .

Jan 1, 1964