Search Documents

By David Hoadley, Kenneth R. Maser, Ashok B. Boghani, James E. Billar, D. Randolph Berry, Mackenzie Burnett, Robert H. Trent

C 6 Automatic Elevator Control Systems An automatic elevator control system, consisting of position sensing devices and a control unit, can be used to control an emergency mine hoist. While automatic elevator control systems are assembled from standard components, they are typically custom designed to suit a given customer's application. Various manufacturers contacted indicated that the price range, less installation, for a simple two-stop control system begins at approximately $2500 and can increase depending upon the type of components used, shaft depth, the type of mechanical drive used, and the maximum operating speed A partial list of elevator control manufacturers follows. They should be contacted for further details. Marshall Elevator Company Pittsburgh, P A 412 -431 -1340 Armor Elevator Company, Inc. Louisville, KY 502-361 -7181

Jan 1, 1976

By Manuel Gomez

Areal distributions for ash, total sulfur, and sulfur forms were developed for the top 12 inches, the middle section, the bottom 8 inches, and the total seam of Pittsburgh coal in southwestern Pennsylvania. The sulfur and ash exhibit an apparent high local variability. As a general rule, both the sulfur and ash show high concentrations in the top 12 inches and in the bottom 8 inches of the seam relative to the concentrations observed in the middle section of the seam. The high-low sulfur and ash concentrations in the top 12 inches of the seam are not coincident with the high-low sulfur and ash concentrations in either the middle section or the bottom 8 inches of the seam. With respect to sulfur and ash, it is suggested that the top and bottom sections of the Pittsburgh coal may reflect both a syngenetic and epigenetic origin. Present data support the belief that paleotopography controlled Pittsburgh seam deposition. Evidence is presented to show that channels were cut at various times into the semilithified sediments that buried the Pittsburgh seam. In this channeling process, portions of the Pittsburgh coal may have been eroded away. Following channel development, the lower part of the Pittsburgh sandstone filled the complex system of braided channels to produce the "want areas" encountered in present mining operations. In localized areas of the Pittsburgh seam, impingement of Pittsburgh sandstone may be responsible for the lateral displacement of the coal. Information of this type becomes important in the assessment of exploration data, in the development of a quality control system for mine output, and in mine life planning.

Jan 1, 1974

By Kenneth M. Earl

The purpose of this investigation was to obtain subsurface information on the John Burdette barite-fluorite deposit, Garrard County, Ky. The deposit was intersected in each of five inclined diamond-drill hales aggregating 1,163 feet. All holes were drilled from the hanging wall of the deposit; the inclinations varied from minus 41° to minus 75°. Disseminated metallic sulfides were noted in the drill cores from holes 1, 2, 4, and 5. The deepest drilling was hole 5, which intersected the deposit at approximately 490 feet down dip. Visual inspection of the cores did not indicate mineralization of economic importance; therefore, no chemical analyses were conducted. Condensed logs of diamond-drill cores are included in this report. All drill cores were shipped to the Bureau of Mines core library in Minneapolis, Minn., for future reference,

Jan 1, 1959

By W. E. Wallace, V. Castranova, P. Hathaway, F. H. Y. Green, E. D. Recad, V. Vallyathan, M. J. Keane

Inhaled particle contact with pulmonary surfactant in the hypophase lining pulmonary alveoli was modeled in vitro by exposing two respirable sized dusts, kaolin and silica quartz, to lecithin, a major component of pulmonary surfactant, emulsified in physiologic saline. Lecithin adsorbs to the dusts upon incubation at 37º C and suppresses their cytotoxicity as measured by pulmonary macrophage and erythrocyte assays, suggesting that pulmonary surfactant provides a defense system against prompt cell membrane lysis by inhaled dusts. Subsequent pulmonary macrophage phagocytosis and lysosomal enzyme digestion of the coated dusts was modeled in vitro by incubation with phospholipase A2 for one hour. With increasing lipase activity, silica hemolytic potential was restored to native silica levels. Kaolin was retoxified to levels far in excess of native kaolin hemolytic potential. Elution, thin layer chromatography and phosphate assay of treated dusts indicate most lecithin on silica is digested to lysolecithin and desorbed, silica retoxification being due to surface and adherent lysolecithin effects. Most lecithin on kaolin is not digested in this same time; that which is results in adherent lysolecithin which is responsible for the kaolin retoxification. Digestion with phospholipases A2 and C together produces only weakly retoxified kaolin. Results suggest that surface adsorption properties which control the adherence of prophylactic surfactant distinguish the pathogenic potentials of quartz, kaolin and mixed dust.

Jun 1, 1988

By P. M. Gruzensky

In view of some of the outstanding properties of chromium, considerable effort has been made in recent years to prepare the high-purity metal in ductile form. The object of this investigation was to obtain such metal by electrolysis of chromic acid solutions and to determine the conditions that yield optimum results. The apparatus is described, as well as the parameters that received consideration. Ion-exchange resins were employed to remove cation impurities from the electrolyte. Tensile specimens prepared from the electrodeposits by arc melting, press forging, swaging, and drawing, were ductile at room temperature. INTRODUCTION Metallic chromium displays an exceptionally high resistance to corrosion, oxidation, and wear at elevated temperatures. Although these properties are utilized to some extent when chromium is alloyed with other metals, such as in stainless steels, high-chromium alloys and pure chromium are not employed as engineering materials because of a serious lack of ductility and impact resistance at room temperature. Because high-chromium alloys appear promising as refractory metals for applications such as in gas turbines, much interest has been shown recently in the preparation of uniformly ductile chromium and in determining which factors contribute to its brittleness.

Jan 1, 1957

By H. L. Gibbs

A portable radon monitoring instrument capable of making on-the-spot measurements of the radon gas content of uranium mine atmospheres was designed and constructed. The monitor was tested in the laboratory and in operating uranium mines. Good correlation was obtained between the monitor readings and radon measurements made on mine atmosphere samples taken in radon bottles.

Jan 1, 1973

By R. H. Storch

This report describes work done as part of a Bureau of Mines program to appraise the titanium-mineral resources of Idaho. The work included both field reconnaissance and a spot churn-drilling program. Much general information was available, as a result of earlier work done under the Western Radioactive Minerals Exploration Program conducted between 1950 and 1954 by the Bureau of Mines for the United States Atomic Energy Commission. This particular exploration provided data as to the quantity of ilmenite (TiFe03) and accessory black-sand mineral concentrates in a number of placer deposits; however, at that time no tests were made to ascertain if the ilmenite was of marketable grade. The spot churn drilling was begun in the Gold Fork area of Long Valley, Valley County, Idaho (fig. 1), in August 1956 and was completed during October of the same year. Eleven holes (designated as the GF series on fig. 2) 35 to 45 feet in depth, aggregating 425 feet, were completed during this period. Data from other exploration drilling in 1951 was used in this report. The 13 holes in the G series shown in figure 2 were drilled by the Bureau of Mines for the United States Atomic Energy Commission; the 7 holes of the DH series were drilled by the Bureau of Reclamation. The 20 holes, ranging from 16 to 140 feet in depth, totaled 1,625 feet. The combined number of all samples recovered was 422. Those taken in 1956 were composited for each drill hole and sent to the Bureau of Mines laboratory in Albany, Oreg., for analyses.

Jan 1, 1958

By Norwood B. Melcher

This report describes preliminary experiments by the Federal Bureau of Mines on the practicability of adding raw pellets of taconite concentrate to blast furnace feeds. The usual industrial practice is to harden the pellets by heating before they are charged to the furnace. The Bureau research demonstrated that raw pellets could be successfully smelted in an experimental furnace with no significant change in coke consumption and only a moderate increase in dust losses. The dust loss was 43 pounds per ton of metal for an all-pellet charge, compared with 7 pounds per ton for an all-sinter charge. Raw taconite pellets undergo only slight degradation during charging to the furnace if 1 percent bentonite is used as a binder. INTRODUCTION Fines and concentrates must be consolidated or agglomerated into larger masses before they can be smelted in a commercial blast furnace. Such agglomeration is usually done by sintering, pelletizing, nodulizing, or briquetting. Sintering has been the more common practice, but with the advent of taconite concentrates pelletizing is increasing in importance.

Jan 1, 1960

By Homer J. Ballinger

A multiple drill carriage or "jumbo," which is believed to be unique in both design and performance, was constructed and has been in use for the past year at the Bureau of Mines experimental oil-shale mine near Rifle, Colo. This jumbo mounts four long feed percussion drills and is so designed that two men can operate all four drills. Before the jumbo was placed in operation, a minimum of eight man-shifts was required to drill 72 fifteen-foot holes in headings 60 feet wide and 27 feet high. The sane round is now drilled by two men in about 6 hours. Over 500 feet of drilling per man shift is easily and consistently accomplished. Use of the jumbo has resulted in a 75 percent reduction in drilling labor and a substantially lower drilling cost.

Jan 1, 1950

By M. K. Larson, J. P. Dunford, E. G. Zahl, T. M. Brady

Researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health, Spokane, WA, have collaborated with three Western longwall coal mines in an on going effort to develop technologies that will aid in providing safe and stable working areas. The goal of the research described here is to develop a stress monitoring system that will provide immediate information to mine managers for making daily safety decisions as areas of poor ground are mined through. Initial work has focused on answering preliminary questions regarding the reliability and use of stress change patterns. Research is concentrated on monitoring horizontal stress because horizontal stress is transmitted over long distances through stiff strata, thus allowing an extended length of entry to be monitored. This paper presents an explanation of the concept, key results from field tests at two mine sites, and a proposed process for implementing a monitoring system. System design layouts, instrument use, data collection and interpretation methods, and processes to present findings to mine staff are described. Additional validation and correlation with actual failure mechanisms are required before this approach can be recommended at ongoing operations. However, initial results indicate that this approach shows promise in mines prone to bumps and roof falls associated with large stress changes. In particular, analyses of measured changes in horizontal stresses appear useful.

By G. M. Martinez

A cell concept adaptable to large-scale electrowinning of zirconium metal from zirconium tetrachloride was investigated by the Federal Bureau of Mines. Tests were made in twin cells, each 12 inches in diameter by 33 inches long. Electrowinning was performed in one chamber from which the electrolyte was transferred after electrolysis to the other chamber where it was renewed by the introduction of ZrC14 by direct sublimation. The formation of a salt plug in the connecting pipe provided a seal between the chambers. Optimum electrolyte composition, with respect to quality of the metal product (91 pct meeting ASTM standards except for the oxygen content) and current-carrying capability (about 350 amp) was determined to be 16.7 wt-pct NaF-83.3 wt-pct NaCl mixture plus ZrC14 equal to about 3 wt-pct zirconium. A twin-cell design incorporating the unit operations covered by this investigation is proposed.

Jan 1, 1976

By J. F. McIlwain

The Bureau of Mines investigated fumes generated by selected welding materials used in mines in order to help determine their relative hazard potential. The initial phases of the study have been completed. A welding-fume generation and collection apparatus was designed, assembled, and calibrated. Five brands of coated, AWS-type E308-16 stainless steel electrodes were tested. Total fume generation rates of 0.39 to 0.51 g/min were measured. Quantitative chemical analyses were conducted for all of the principal firms constituents. Two analytical schemes were used to determine levels of the Cr6+ and Cr3+ species contained in the welding fumes; comparable results were obtained. The Cr6+ was found to be the most hazardous constituent, leading to a maximum allowable total fume exposure of 1 mg/m3. Fume generation rates and fume constituent analyses will be derived for other groups of welding electrodes using similar procedures.

Jan 1, 1983

By Jr. Hardy, H. Warren Shen

"A study is presently underway by the authors to investigate the character of the bit-coal interaction during coal cutting and its influence on the size and shape distributions of the generated dust. An important aspect of this on-going project is the development of acoustic emission (AE) criteria which would make it possible to carry out remote monitoring of coal cutting operations. The on-going AE studies are fundamental in form and were undertaken to evaluate the general feasibility of AE monitoring techniques using simplified coal breakage and cutting procedures. The present paper will focus on the test facilities, experimental techniques, and results associated with linear, single-bit cutting. An AE-transducer, attached directly to the bit, detected AE signals during the cutting process.Experiments have been carried out on seven specimens of coal obtained from the USBM experimental mine at Bruceton, Pennsylvania. Three separate cuts were made for each of two bit angles (10 and 45 degrees) and two bit velocities (0.085 and 0.169 cm/sec), for a total of 12 separate cuts. Data associated with resulting particle size distribution and AE characteristics (major dominant frequency components) will be discussed. Data analysis has also been underway using a computer-based pattern recognition system known as ICEPAK (Intelligent Classifier Engineering Package). This program is able to evaluate over 100 features of an AE event and to make objective comparisons between AE signals associated with different loading or cutting parameters. The results to date show that AE generated during some of the test conditions can be recognized by ICEPAK with a recognition rate of 90% and higher while other conditions cannot at present be separated with a suitable recognition rate. Further analysis of the experimental data is presently underway.The reduction of the severity, and eventual elimination, of Coal Workers' Pneumoconiosis (CWP) depends on gaining fundamental understanding in a number of major areas. These include dust generation and entrainment, transportation, suppression, medical effects of dust, and possible treatment. At present a project is underway by the authors to investigate the character of the bit-coal interaction during coal cutting and its influence on the size and shape distributions of the generated dust. An important aspect of this on-going project is the development of acoustic emission (AE) criteria which would make it possible to carry out remote monitoring of coal cutting operations. Suitable on-line analysis of monitored AE data would allow engineers to evaluate factors such as shearer bit conditions and cutting efficiency, and to quantify the particle size and shape distribution of the generateddust. The on-going AE studies are fundamental in form and were undertaken to evaluate the general feasibility of AE monitoring techniques using simplified coal cutting procedures. To date experiments have been carried out on coal under uniaxial compression, linear single-bit cutting, and cutting using a laboratory-scale, single-bit shearer. A brief outline of the overall study has been presented in an earlier paper (Hardy, Shen and Kimble, 1995). This paper will consider the linear single-bit cutting studies in more detail.It is generally accepted today that most solids emit low-level seismic signals when they are stressed or deformed. In this paper this phenomenon will be referred to as acoustic emission (Hardy 1972, 1981, 1989). In essence, the measurement of AE activity in a field or laboratory structure is relatively simple. A suitable transducer is attached to the structure, the output of the transducer is connected to an associated monitoring system, and the AE signals occurring in the structure, due to internal or external stress, deformation, and failure are suitably acquired, pre¬processed and recorded."

Jan 1, 1998

By D. E. Seizinger

Analytical methods for oxygenates in exhaust gases were studied, and emissions of these compounds from automotive engines were measured with and without an oxidation catalyst in the exhaust system. Hydrocarbons, simple mixtures of hydrocarbons, and a single gasoline were used as fuels. With the more complex gasoline, successful analysis was possible only with exhaust from the catalytic system which preferentially converted and thus removed interfering hydrocarbon species. However, it was shown that an estimate of the oxygenate yield from gasoline used in a noncatalytic system can be synthesized from data obtained with simple fuels. Such synthesized data were used for comparison of noncatalytic with catalytic systems. Compared with those of previous studies, results of this work indicate that the action of the catalyst introduced no new oxygenates and reduced both the carbonyl and the total of oxygenates. It is concluded that the compositional character and class distribution of oxygenates in exhaust from catalytic systems may differ significantly from the composition and distribution for oxygenates not subjected to catalytic conversion. The findings also support previous estimates that noncarbonyls may constitute a significant fraction of exhaust oxygenates and may warrant attention in procedures for measurement of the oxygenates.

Jan 1, 1973

By Henry M. Harris

The Bureau of Mines investigated a glass containing approximately 17 percent lithia and 83 percent silica to establish a method of devitrifying cast and rolled shapes. Glass shapes with high strength were made by melting, forming, and rapid cooling of the composition, and the shapes subsequently were converted to a crystalline condition by heat treatment. The best devitrification schedule included rapid cooling of the glass to below 300° C, followed by reheating at a rate of 50° to 400° C per hour, depending on the size of the shape, followed by a of 60 to 70 hours at 500° C and another period of 15 hours at 800° C. attempts to use faster heating rates or slow cooling to accomplish devitrification in deformation of the shapes. The crystalline shapes had flexural strengths that averaged over 33,000 psi, achieved with an annealing time of 60 to 70 hours at 500° C.

Jan 1, 1965

By E. J. Matson

The Little Castle Creek chromite deposit was examined in February and May 1941, respectively, by W. O. Vandenburg and O. H. Metzger, engineers of the Bureau of Mines. The Federal Geological Survey started a magnetometer survey of the area in November 1940 and completed its work during April and May 1941. Field work by the Bureau of Mines was conducted during May and June 1941. The purpose of the Bureau of Mines investigation was to search for a continuation of the chromite mineralization. The property at one time was the largest chromite producer in California.

Jan 1, 1949

By Robert L. Lagace, N. Albert Moussa

The objective of this project was to perform a preliminary study to determine the desirability/practicality of burying the communication cables in underground mines in order to protect then from the effects of fires and explosions We conducted discussions with Government and industry specialists on the physics of mine fires and explosions, mine disaster fighting, rescue, and investigation activities, and on nine operations. In addition we examined published experimental work and selected detailed NSHA accident reports on fires and explosions in underground mines. We found the overall desirability /practicality of cable burial must be regarded at this time as highly questionable, because of its benefit limitations to special sceneries, its practical operational shortcomings, and the availability of alternative cable protection options.

Jan 2, 1982

A revolutionary development in blasting materials has occurred in the past 5 years. Ammonium nitrate, sensitized by the addition of a few percent of No. (class) 2 diesel fuel or other suitable petroleum product, has been adopted as a low-cost, efficient blasting agent2/ by a wide variety of mining and heavy construction operations. Moreover, ready availability of the component supplies throughout the Nation and ease of their formulation into effective blasting agents have made it possible for the blaster himself to pre-pare the mixes at the site of use. Although these field-mixed products have partly or wholly displaced explosives such as dynamites in some applications, there are other blasting operations where the fuel-sensitized ammonium nitrate agents do not appear to be well adapted. Important safety characteristics are inherent in ammonium nitrate-based blasting agents prepared under competent factory control, or when field mixed under equivalent close control--as long as the hazards they present are clearly understood and respected. This publication attempts to summarize knowledge of those hazards and to incorporate practical ways to cope with them. A series of safety recommendations thus is presented. These recommendations cover the preparation, storage, transportation, and use of field-mixed ammonium nitrate blasting agents.

Jan 1, 1960

By Oleg Terichow

Electrophoretic mobility measurements were made by the Bureau of Mines on samples of a Florida phosphate slime to determine the optimum conditions of coagulation and settling in an aluminum sulfate solution. Addition of anthracite to promote mutual coagulation demonstrated the practicability of heterocoagulation by reduction of the repulsive effect of double layers. By proper selection of the electrolyte and its concentration, the reduction of the double layers to a net zero point of charge causes the predominance of Van der Waals' forces of attraction leading to the coagulation and rapid settling of both particle systems, as is predicted by the Derjaguin-Landau-Verwey-Overbeek theory of colloidal stability. Confirmation was found in the microfiltration tests where a modified Carman equation was applied to evaluate the specific filter bed resistance.

Jan 1, 1975

By M. J. Spendlove, P. P. Zapponi

"INTRODUCTION In carbothermic processes for the production of magnesium, magnesium oxide is reduced by carbon according to the following equation:(1) MgO + C = Mg(g) + CO.The reaction is virtually complete at temperatures above 2,000° C. but reverses rapidly at somewhat lower temperatures. To produce magnesium by this reaction, therefore, it is necessary to cool the gas very rapidly to a temperature at which the rate of the reverse reaction becomes negligible. Several media for quenching the gas have been proposed, among which are hydrogen, natural gas, liquid hydrocarbons, and molten metals of low melting point.The results of a preliminary investigation on the use of molten lead as the quenching medium are summarized in this report. The work was done in 1941, when the threat of war made it imperative to investigate every process that offered possibilities for rapid expansion of domestic production of magnesium. Although the results were encouraging, other processes appeared to offer better prospects for immediate wartime development, so the work was not continued. Shortly before the investigation was completed, several patents on the use of low-melting metals for absorption of magnesium vapors appeared, 4/"

Jun 1, 1947