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By L. A. Morley

Volume IV of the final report examines the problem of indirect contact of overhead high-voltage power lines by mining personnel. This refers to the contact of energized lines by workers through some intermediate conductor such as a metallic tool or a piece of high-reaching mobile equipment, thus the term "indirect contact." The shock hazard presented by such contact has been a major cause of electrical fatalities associated with mining operations. The report volume is divided into three major areas. The first gives a general background of overhead lines, basic characteristics, and associated hazards, and continues to describe presently used techniques and devices which attempt to alleviate the contact problem. The second area narrows the discussion to the mining industry by presenting a detailed analysis of 39 overhead-line contact accidents in mining since 1970. The third major section uses the information from the first two areas to formulate recommendations to prevent these accidents and subsequent electrocutions at mining operations.

Jan 1, 1982

By Arnold C. Love

This report discusses current research by the U.S. Bureau of Mines on the effects of whole-body vibration (WBV) and shock on underground mobile equipment operators. The highlights of a comprehensive literature review of WBV, shock, and seating are presented. Factors discussed include health and physiological effects, comfort, performance, and fatigue. Vibration data were collected from shuttle cars and ramcars at several underground coal mines in Pennsylvania, Ohio, and Illinois. The data were formatted so that they could be used to drive the Bureau's motion platform, and to compare them with ANSI S3-1979, Guide for the Evaluation of Human Exposure to Whole-Body Vibration. Human subject testing in the Bureau's vibration research laboratory evaluated the effects of two different seat angles and of the presence or absence of vibration and of foam padding on heart rate, blood pressure, and subjective discomfort. Only vibration significantly increased heart rate and systolic and mean blood pressures. Vibration and a steel seat had a significant effect on subjective discomfort. The apparatus used for these tests and the experimental procedures are described in detail. Recommendations are made for additional research on the exposure of underground mining machine operators to WBV and shock.

Jan 1, 2010

By Robert J. Brennan, Edward R. Navrocky, John W. Buch

In an effort to establish a highly productive mechanized mining system for anthracite beds pitching between 10 ° and 20 ° , for which conventional mobile equipment is not adaptable , the Bureau carried out an experiment in longwall mining using an Anderton- type drum cutter loader and friction - type yielding steel roof supports . The roof- support system proved to be inadequate for breaking the overhanging roof at the break line supports , with the result that the roof broke over the solid coal . The accompanying subsidence destroyed the continuity of the roof in the work area , and the project was discontinued .

Jan 1, 1964

By D. M. Lewis, J. K. H. Ma, Y. Rojanasakul, J. Y. C. Ma, J. H. Kang, V. Castronova

"Tetrandrine is a bisbenzylisoquinoline alkaloid which has been shown to exhibit antifibrotic activity against silicosis. Tetrandrine is characterized by its strong binding to alveolar macrophages and inhibition of particle-induced respiratory burst activity in these phagocytes. In contrast, tubocurine and tubocurarine are structurally similar to tetrandrine but exhibit little effect on fibrosis or activation of alveolar macrophages. The objective of the present study was to test the effect of tetrandrine on macrophage production of monokines in response to occupational dusts, and to determine tetrandrine's effect on monokine-medicated cell growth using a mouse thymocyte proliferation assay and lipopolysaccharide (LPS) as a positive control. Stimulation of alveolar macrophages by respirable silica dust resulted in a release of monokines which caused a fourfold increase in thymocyte proliferation. Coal dust, on the other hand, had no effect on macrophage production of this cytokine. Tetrandrine was found to exhibit a dose-dependent inhibition of monokine release from both silica and LPS-stimulated alveolar macrophages. In experiments where thymocytes were directly treated with tetrandrine, a dose-dependent inhibition of thymocyte proliferation was noted with both interleukin-1- (IL-1) specific and nonspecific mitogenic (concanavalin A) actions. In contrast to the inhibitory potency of tetrandrine, tubocurarine was found to have no effect on either the production of monokines by LPS-stimulated alveolar macrophages or IL-I-mediated thymocyte proliferation. These results provide a correlation between the ant:fibrotic effect of tetrandrine and inhibition of macrophage activation. INTRODUCTIONThe pathogenesis of chronic pulmonary fibrosis caused by inhalation of occupational dusts has been associated with abnormal activation of alveolar macrophages such as the release of various cytokines capable of inducing fibroblast proliferation and collagen synthesis. These macrophage-derived cytokines include interleukin-1 (IL-1), tumor necrosis factor (TNF), platelet-derived growth factor (PDGF), transforming growth factor-B (TGF-(B), macrophage derived growth factor (MDGF), and interferon [1, 2].Interleukin-1 is a major macrophage-derived cytokine that has been shown to exhibit multiple biological effects on a variety of target cells. It is known to cause leukocyte [3, 4] and endothelial cell activation [5, 6], and to affect the synthesis and maintenance of the extracellular matrix by stimulation of fibroblast proliferation [7-9], synthesis of collagens [10] and gluco-saminoglycans [11], and prostaglandin E2 production [12]. In addition, IL-1 plays an important role in the initiation of an immune response through its direct activation of lymphocytes and stimulation of the production of other cytokines, such as interferons and hemopoietic colony-stimulating factors, needed for the expression of an immune response [13]. As a major cytokine in the immune-inflammatory sequela, IL-1 is also produced by epidermal, epithelial, lymphoid, and vascular tissues after infection, injury, or antigenic challenge [14]. Agents such as lipopolysaccharide (LPS), phorbol myristate acetate (PMA), immune complexes, and particulates are known to activate the synthesis and release of IL-1 by monocytes and macrophages [15]. These substances also trigger intracellular signals leading to altered arachidonic acid metabolism. Although the mechanism is still not clear, prostaglandins have been shown to suppress IL-1 translation via the induction of cyclic adenosine-monophosphate (CAMP), whereas leukotrienes produce a positive signal for IL-1 production [13]."

Mar 1, 1992

By David Schlain

A small alumina reduction cell with a graphite crucible and boron nitride liner was developed by the Bureau of Mines as the initial phase of a study of the reactions which occur in the reduction of alumina by the Hall-Heroult process. Operating conditions in the cell such as temperature, time, current density, electrolyte composition, and electrode materials may be varied easily. Aluminum was produced in the cell at a current efficiency of about 75 percent and a cell voltage of 2.7 volts. Although the data are not wholly conclusive, the operation of the cell did not appear to be greatly affected by large changes in temperature, electrode spacing, current density, and alumina concentration in the electrolyte.

Jan 1, 1963

By Donald F. MacDonald

This report aims to discuss, from the viewpoint of the mining geologist, the bearing of topographic and geologic conditions on cer- tain problems that arose in the construction of the Panama Canal. T+ is published by the Bureau of Mines as a contribution to engineer- ing liters ure because it presents information that shows how geology and topography must be considered by the mining engineer in plan- ning excavations and in removing loose material and solid rock in the safest and most efficient manner. The printing of this bulletin has been approved by the governor of the Panama Canal, as it was impracticable for the Panama Canal to give this information to the general public in any of its publications. The "sword cut" of Goethals and his men did not sever the Isth- mian barrier; it merely clove the hills to a depth of 40 feet above sea level. This cut and the great areas of low valleys at both ends of it have been covered with fresh water to the 85-foot level. This high-level lake held by dams at either end, the 85-foot locks, by which ships enter it, and the dredged approaches from the two oceans constitute the Panama Canal. In the preparation of accurate estimates concerning the cost of large excavations information regarding the geologic conditions, as obtained by a study of natural features, is necessary. Drill holes and test pits will furnish supplementary geologic information, but without a gen- eral knowledge of the geologic conditions it will not be possible for the constructing engineer to answer such questions as the following: (1) What rock units will be encountered in the excavation and in what proportion? (2) What will be the cost of drilling each for blasting (3) How far apart and how deep must the drill holes be to efficiently break the rock of each to the proper size-not too fine nor yet too coarse? In this connection jointing, fissuring, bedding, toughness, and other physical characteristics must be considered (4) How steep will the slopes of the excavation stand, and to what extent will they wash and trench on exposure to the atmosphere? (5) What proportion of the material to be excavated is of such physical character that it may be utilized in any other part of the project, such as in concrete construction, road making, wharves, breakwaters, riprap work, etc.

Jan 1, 1915

By R. V. Ramani, P. M. T. White, D. Sutton

Appendix I. Part 1: Description Of Geology & Reserves System Introduction The Ore Evaluation and Reserve programs have been developed to aid in the evaluation of coal deposits, both qualitatively and quantitatively. The "Weighted Moving Average" technique used provides considerable flexibility in dealing with diverse parameters with differing distribution characteristics. Determination of Model Constants "a" and "k" - Unit 1 The flexibility of the method in dealing with diverse value parameter distributions lies in its ability to cater to the individual characteristics of each. These characteristics are embodied in the values determined for constants "a" and "k", namely, local and regional variations in value distributions, respectively. The empirical method used attempts to optimize the "a" - "k" combination. Realistic values for "a" and "k" are entered into the program together with sample values for the required parameters and their respective coordinate location values. All the values within a specified radius from the point being evaluated are used to interpolate a value at that point. (Note, the interpolated point is the location of one of the boreholes, values of which are not used in the calcula¬tion.) 3n a similar manner, interpolated values are calculated for each borehole location and for each parameter. This is done for each possible combination of "a" and "k".

Jan 1, 1974

By D. E. Shanks

This U.S. Bureau of Mines (USBM) research simplified an earlier hydrogen chloride (HCI) leach-sparge process developed by the USBM to recover reduction-grade alumina from domestic kaolin clay. Improvements were made by decreasing the initial leaching acid concentration from 25 to 20 pet, decreasing the leaching time from 1 to 2 h to 15 to 30 min, eliminating the solvent extraction step for Fe removal, and eliminating the step to recover the AI content of the bleedstream circuit. A 10-cycle bench-scale experiment of the simplified process showed that the ferric chloride (FeC13) concentration built up to 9.3 g/L in the recycle stream. This did not interfere with any of the unit operations or final alumina product purity because Fe forms stable soluble chloride complexes when sparged with HCI and is easily washed from the large aluminum chloride hexahydrate (ACH) crystals. The reduced leaching time and acid concentration did not decrease Al extraction.

Jan 1, 2010

By M. L. Skow

Large tonnages of the manganese ores found in Aroostook County, Maine, are refractory to conventional mineral-dressing techniques and to the common chemical- extraction procedures. The Maple Mountain-Hovey Mountain ores are typical of this type. Because the most promising method of recovering the manganese from these ores has been a chloridizing roast in which the ground ore is in contact with gaseous hydrogen chloride, preliminary batch tests were made with a fluidized bed. On the basis of these tests, it was concluded that fluidization, with careful control of operating conditions, could be employed for this cloridization and warrants further study. Selective volatilization of the iron at 600° C. was unsuccessful. An operating temperature of approximately 950° C. was necessary for a practicable rate of volatilization of manganese chloride. Hydrogen chloride contents of 10 to 100 percent of the fluidized gas gave essentially equivalent manganese recoveries with an 80- minute retention time, For shorter periods reaction was more complete with the higher hydrogen chloride concentrations. At the 80-minute retention period the lower hydrogen chloride concentrations volatilized somewhat less iron and also improved the physical operation of the process. Fluidization gave results superior to comparable tests on chloridization in a fixed bed.

Jan 1, 1956

By Jarrell C. Grout

The Bureau of Mines has developed a computer program for use in solving nonlinear regression problems. The program is written in a general form so that, regardless of the functional relationship, the unknown parameters may be evaluated by either the Gauss-Newton or the Newton-Raphson methods of iteration. Variances and covariances of the parameters, as derived from the law for the propagation of errors, are also determined.

Jan 1, 1969

By H. P. Holmes

Tonnage quantities of hafnium metal have been prepared in Kroll-process equipment designed for producing zirconium. Some slight process modifications have been necessary, but overall operation is the same as for zirconium. Hafnium oxide is chlorinated in the presence of carbon and the resultant hafnium tetrachloride reduced by magnesium metal. Byproduct magnesium chloride is removed in a high-vacuum distillation step and the hafnium sponge metal crushed for further use. Arc-melted metal can be forged and rolled to sheet, but the best material produced to date would not be considered cold ductile. INTRODUCTION This investigation is part of the program for the production of pure metals from domestic and foreign ores that has been underway at the Bureau of Mines for several years. It was done in cooperation with the Atomic Energy Commission and the Bureau of Ships.

Jan 1, 1955

By Henry Kreisinger, WALTER T. RAY

This bulletin contains a statement of certain results that will be embodied in a report describing investigations of the combustion of fuel made by the United States Geological Survey and the Bureau of Mines in a specially constructed long furnace. The furnace forms part of the fuel-testing plant at Pittsburg, Pa., which was established and equipped by t.he Geological Survey, but passed under the control of the Bureau of Mines on July 1, 1910, when a t.ransfer of fuel-test.ing investjgations, authorized by act of Congress, became effective. The work discussed in this bulletin was done under the direction of the Geological Survey. The furnace was designed and built for an experimental study of the processes of combustiop, this study being part of a comprehensive plan for testing fuels to determine their heat value and the manner in which they can be used to best advantage. Although the main object of the researches made with the furnace by the Geological Survey was to examine critically the production of sensible heat by combustion along the path of the gases rising from the fuel, an interesting as well as important side problem developed in the study of the simultaneous dissipation of the heat through the walls and roof . of the furnace. Thus incidental data were collected on the temperature gradient through the walls at several places. These temperature data. (together with the heat conductivity of the material of the walls) formed the basis for calculating the heat dissipated through the walls. The object of this report is to present and discuss these temperature data. The discussion particularly concerns the air-space type of wall construction as compared with the solid brick wall or walls type, in which the air space is filled with some solid material of low heat conductivity. The conclusion of the authors, which perhaps will surprise some readers, is that, so far as loss of heat is concerned, a solid wall of brick or any ordinary material is preferable to a hollow wall of the same total thickness, especially if the air space in the hollow wall is near the furnace side. There is a general belief that l?ince air is a poor conductor of heat, air spaces built into the walls of a furnace will prevent or reduce heat dissipation through the wa.lls. Although there may be instances of furnace walls in which such construction reduces the rate of heat flow through them, yet as a rule the effect of the air space is just the opposite. While the heat does travel very slowly through the air by conduction, it leaps over the air space readily by radiation. Although this latter mode of heat propagation is common in nature, the laws governing it are not generall;y known and are seldom taken into consideration when furnace walls are being designed. It may be stated here that the quantity of heat passing through a. portion of a solid wall by conduction depends on the difference between the temperatures of the two planes limiting the portion of the wall. The quantity of heat that passes across the air space in the waH depends on the difference of the fourth powers of the absolute temperatUI: es of the surfaces inclosing Hie air space. It follows that, in case the heat. passes by conduction through the solid'portion of the wall, the loss remains approximately the same so long as the temperature of the two limiting planes remains constant, no matter what may be the temperature of the two planes. On the other hand, the heat passing across the air space by radiation increases rapidly with the temperatures of the inclosing surfaces, although the difference between these temperatures may remain constant. This feature will be shown by curves in the latter part of this paper and thoroughly discussed. The important point is that the air space, which is advantageous in the walls of a refrigerator because the temperatures are low, is objectionable in a furnace wall because the temperatures are high. It is customary to put air spaces in furnace walls between the firebrick linings and the common brick. Usually the fire-brick lining is only half a brick thick, which construction brings the air space too close to the furnace. The result is that the temperatures of the surfaces inclosing the air spaces are too high, and in consequence too much heat is radiated across the spaces. The heat passing through such walls would be much reduced if the air spaces were filled with brick, or, better, with some cheap nonconducting materials, such as ash, sand, mineral wool, etc. Even where the fire-brick lining is one brick thick (9 inches), the temperature in the furnace may be high enough to raise the temperatures of the air-space surfaces so much that the heat radiated across the space will amount to more than would the heat conducted through a filling, were the filling only common brick. This last statement is amply justified by the data here presented.

Jan 1, 1911

A symposium on the health hazards of respirable dust in the mining and milling of talc was held on May 8, 1973, in Washington, D.C. The results of medical effects on both human and animal subjects were presented. Methods for identification and classification of talc minerals were also presented. Analytical techniques discussed included X-ray diffraction, scanning electron microscope observation, electron probe, and optical microscopy.

Jan 1, 1974

By A. F. Baker

Tests were conducted in commercial foundries to determine the suitability of calcined anthracite as a cupola fuel. The calcined anthracite performed satisfactorily at two of the three foundries where iron-melting tests were conducted. Performance at the third installation was unsatisfactory because metal temperatures deviated widely and, in general, were lower than is desirable for the type of castings being made.

Jan 1, 1963

By Bruce Maxwell

The deformation modulus of coal mine pillars theoretically can be reduced by drilling holes in advance of the mining face. This reduction of modulus along the edge of the pillar has the effect of decreasing the stress concentration in the roof; control of roof caving is thereby predicted. Initial field work indicated that a high horizontal stress field existed at the field test site: Subsequent field work was undertaken to confirm the high horizontal stress field and to attempt to relieve the horizontal stress in the immediate roof. A method of softening pillars in conjunction with normal mining activity was developed. Instruments to measure horizontal roof strain, roof parting, roof tilt at the rib, and changes in vertical and horizontal stress in the roof and in the coal were used. These instruments were installed in both softened and unsoftened entries and in locations to indicate the effect of vertical slots in the roof. Significant stress reduction due to pillar softening was indicated, but the effect of this reduction on roof stability was not established. The vertical roof slots relieved the horizontal stress in the immediate roof very effectively, and observations of roof conditions indicated that the slots definitely improved roof stability.

Jan 1, 1977

By FREDERICK H. WILLCOX

In the past the blast-furnace industry was under the stigma of being one of the most prolific sources of killed or seriously inj ured and permanently disabled workmen of any of the industries of the country. In the popular mind, labor at blast furnaces was little less hazardous than mining, powder making, or railroad work. This impression wasbased not so much on definite knowledge of the number actnally injured and the causes of injury as on the spectacular nature of the accidents that from time to time were described in the press. As with a mine disaster or a railroad wreck so with many furnace accidents, the number fatally injured in such accidents constitutes only a minor proportion of the workmen who suffer more or less serious injuries. However, the reader of the daily paper receives a distinct impression-of frightful and sudden disaster which is apt to be associated henceforth in his mind with work at blast furnaces. It is true that in the past this impression has not been without warrant, for from the time of the advent of Mesabi ores, taller furnaces, and faster smelting, which begain in the early nineties, the newspapers have chronicled a large number of blastfurnace disasters. Blast-furnace men have never assumed to tolerate failures in construction or defective control of furnaces. But the admitted hazards of the work are many, and the slow development of improvements in the construction and control of the furnace and its auxiliaries have occasionally given rise to a tendency to accept as a part of the day's work not only the unforeseen and difficultly controlled accidents but accidents whose recurrence might be stopped by the adoption of suitable preventive measures. In the smelting of iron, even more than in many other industries, safety is inseparably related to efficiency in production, and. the accidents strictly incident to work about the furnace are proportional in some degree to the success with which obstacles to smooth working are overcome. This relation does not hold, however, in regard .to such accidents as are incident to hand labor, falls, falling and flying objects, machinery, and the use of hand tools.

Jan 1, 1917

Five conclusions that emerged from ADL's Contractor Noise Measurements Assessment done for the Bureau of Mines and the 7 December 1971 Bureau of Mines Contractors' Round Table Meeting in Boulder, Colorado were: ? a limited amount of good data has been obtained for characterizing the noise environment for electromagnetic (EM) coal mine operational/emergency communications systems; ? significant noise date gaps still exist; ? suitable instrumentation and data analysis methods are available for filling these data gaps; ? the immediate and most important data gaps should be filled by means of a timely field measurement effort that is purposely limited in scope and duration; ? this field measurement effort should preferably be carried out by a team knowledgeable and experienced in coal mine EM noise measurements.

Jan 1, 1972

By Bernadette Michalski

Although hydrocarbons accounted for more than 60% of Bahrain's income and more than 80% of export earnings, this island nation sustained one of the more diversified economies in the Gulf Region. The availability of low-cost natural gas for electric power has fostered the development of a significant aluminum refining and manufacturing industry with emphasis on vertical integration. The Bahraini iron pelletization plant, closed since 1986 due to financial problems, was scheduled to reopen by early 1989. Commodity Review Metals.-Aluminum.-Aluminium Bah-rain Bsc (Alba) attained record high production levels in 1988 taking advantage of favorable aluminum prices, which averaged over $2,000 per ton as compared with less than $1,500 per ton in 1987. Net aluminum production was nearly 13,000 tons over design capacity. Fewer standard ingots (52,081 tons as compared with 79,685 in 1987) were produced as Alba concentrated on higher value added products such as rolling ingots (42,324 tons as compared with 32,125 tons) and extrusion billets (60,934 tons as compared with 46,618 tons).

Jan 1, 1990

In this U.S. Bureau of Mines report, two drill-split mechanical excavation mining system concepts are described, casted, and cost compared with conventional drill-blast mining systems. The concepts for the two drill-split mechanical excavation mining systems presented are (1) a method for steeply dipping narrow veins 0.6 to 1.2 m wide and (2) a longwall method for fiat-lying tabular ores. In the proposed systems, 70 to 80 pet of the ore is disposed of underground as backfill. For sortable ores, face area crushing, sorting, and direct stowage of run-of-mine waste and low-grade ores are proposed. The underground sorting and stowing of waste reduce materials handling, processing, and waste disposal costs by reducing the quality of ore transported to the surface by 70 to 80 pet (by volume). Because many of the tools and techniques proposed for use in these systems have little or no historical mining industry use, cost assignations are heavily influenced by engineering judgments and presented as prefeasibility-level cost estimates. These estimates, presented as discounted-cash-flow-rate-of-return (DCFROR) values, show the proposed systems to be at least as profitable as, and in some cases 50 pet more profitable than, conventional drill-blast mining.

Jan 1, 1994

By H. W. Kilau

The Bureau of Mines evaluated synthetic fluorspar as a substitute for natural fluorspar flux in basic cupola ironmaking. The synthetic fluor-spars tested were prepared from waste fluosilicic acid generated during the processing of fluorapatite ore. The cupola trials showed the synthetic products to be the equivalent of natural fluorspar from an operational standpoint. However, wet scrubber sampling showed that substantial losses of volatilized fluorine occurred from the cupola during operation. The losses during synthetic fluorspar trials considerably exceeded those from natural fluorspar trials. Laboratory viscosity testing, using a high-temperature rotational viscometer, confirmed this finding and indicated that fluorspar volatility in slags is related to slag basicity. Synthetic fluorspar is accordingly recommended more for highly basic cupola operation (>1.3 basicity) than for neutral or acid operation, because of the increased potential for pollution and baghouse filter detezioration"

Jan 1, 1989