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By N. M. Safaya

Moderate to acute deficiency of plant available phosphorus is very common in western coal mine spoils and topsoils. Although some of the spoils are known to contain seemingly adequate amounts of total phosphorus, the plant available phosphorus is so low that it constitutes a serious plant growth limiting factor in the mined lands. For the revegetation of these spoils, the use of species, varieties and ecotypes exhibiting greater efficiency for P uptake and utilization, or conversely, lesser susceptibility to P deficiency would be highly desirable. To identify such plants, quick and adequate methods of screening germplasm should he available. In the present growth chamber study several plant species were screened using continuous flow culture and spoil culture systems to provide information on their relative susceptibility. In flow cultures, P was maintained at 0.25, 2.5, and 25 moles; while in spoil cultures it was applied at 0, 25, and 75µg/g to a P-deficient spoil. Phosphorus deficiency symptoms appeared in alfalfa cultivars, birdsfoot trefoil, emerald crownvetch and yellow sweetclover within 7-10 days upon transfer of their seedlings to U.25 or 2.5 µM P solutions. Burning bush and Russian thistle, found abundantly as pioneering species on mine spoils, showed no deficiency symptoms; their shoot dry matter yield in the 0.25µM P treatment was 24% and 36%, respectively of their maximum yield obtained with 25 µM P. However, the percent increase in the dry matter yield of legumes with 0.25 µM P ranged from 7-13% over their maximum yield. With the increase in solution P concentration, the root dry weight ratio in the legumes increased from an average of 0.22 to 0.43, while in the weeds from 0.14 to 0.30. The low susceptibility of Russian thistle to P deficiency was also demonstrated in the spoil culture experiment. Legumes showed greater response to P-fertilization on the spoil than did the two weeds. With increasing concentrations of P in the solution, the root weight ratio of all the species decreased. At 25 µM P, weeds invested only 14% of their total dry matter yield in the root fraction, where as legumes and grasses invested as much as 24% and 33% respectively. Weedy species averaged higher P concentrations than the legumes and grasses. The mean P concentrations of alfalfa cultivars were the lowest among legumes. In general, P concentrations increased with the increase in P supply. In the flow culture system, P supply increased the Ca levels of legumes. The mean Mn concentrations were highest in the weedy species. The increases in P supply decreased Zn levels in all of the species. File effects of P fertilization on the tissue concentrations of Mn and Zn in spoil culture were similar to that of flow culture system. From this preliminary study, it may be concluded that the continuous flow culture system is efficient in rapid screening of a large number of species under controlled conditions for their efficiency in adapting to mineral stresses.

Jan 1, 1982

By J. Roth

The purpose of the present study is to increase the safety of explosive storage. This was accomplished by: a) review of the histories of recent and past magazine explosions to define causes and trends; b) observation of present-day explosive storage conditions and practices at active mines; c) examination of existing Federal regulations on explosive storage to determine whether they address all conceivable safety problems, whether they contain redundant or obsolete standards, and whether their intent is clearly stated; d) recommendation, for safety improvements and for revision and clarification (if necessity) of governmental regulations. Magazine explosions are rare. A recent increase in magazine explosion frequency must be attributed to a large increase in deliberate (criminal or malicious mischief) explosions. Fires of various origins account for the remaining explosions of the past decade. During 1884-1926 several lightning-generated explosions occurred in non-metal magazines, but none recently. It appears that the contents of a well-constructed, metal magazine are immune to direct lightning strikes, regardless of whether the magazine is grounded or not grounded. Grounding a metal magazine cannot be harmful, but it may well be superfluous. Magazines were observed at 34 widely separated mines and storage problems were discussed with personnel at these mines. In general, storage conditions and practices were found to be satisfactory. Usually, only small quantities of explosives are stored on mine property since most explosives are brought in by suppliers when needed. MSHA and BATF standards on explosive storage appear to cover safety aspects adequately. However, certain revisions are recommended to clarify some of these standards and to reduce inconsistencies in their enforcement.

Jan 1, 1983

By J. R. Thoenen

This circular is part 6 of the third paper (entitled "Excavation") of a series summarizing the technical problems involved in the production and preparation of sand and gravel. Part 1 discussed the use of power shovels, draglines, and excavator cranes; part 2, power scrapers, slackline cableway excavators, and hydraulic monitors; part 3, hydraulic, clamshall, ladder, and diaper dredges; part 4, haulage equipment, particularly industrial cars with locomotive or hoist as the motive power; part 5, conveyor belt, motor truck, pump and pipe line, towboat and barges, and aerial-trams haulage. This circular discusses the application of these various types of equipment to the different types of sand and gravel deposits and contains a reference bibliography. It completes the discussion of excavating problems.

Jan 1, 1936

By Mark I. Copeland

A study was conducted to determine if commonly used alloying additions or coating materials can prevent the formation of a liquid-copper phase during the reheating of copper-containing steels. If so, the tendency of such steels to surface-crack during hot-working might be eliminated. Steel specimens were scaled by heating them either isothermally or in a programed manner that simulated industrial furnace practice. Metallographic examination of the heated specimens showed that molten fayalite (Fe2Si04) completely prevented the formation of liquid copper at the surface. Fayalite, which melts at 2,200° F (1,205° C), was formed by internal oxidation of the silicon contained in the steel. By forming complex molten oxides, coatings of borax glass were also effective in preventing the occurrence of liquid copper at the steel surface.

Jan 1, 1972

To develop more accurate means of measuring low ventilating air velocities in underground mines to facilitate compliance with ventilation standards. The Approach: A commercially available vane anemometer which produces an electrical, rather than a mechanical, output was coupled to electronic circuitry to produce the Bureau's Digital Low Velocity Anemometer (see photo). [ ] How It Works: The experimental instrument has a vane anemometer head which produces an electrical output signal with a frequency directly proportional to the rotating speed of the vane anemometer shaft. The commercially available ABBIRKO FLOWMASTER anemometer head was used in this instrument. In the signal conditioning circuits the electrical signal from the anemometer is converted into pulses, which are counted during either 3-second or 1-minute intervals, depending on the position of the operator's control switch. (Readout is either "instantaneous" or averaged for a period of one minute.) The number of pulses counted is then translated (integrated and divided by a constant) in the logic circuits to get average speed. Average air velocity in feet per minute is displayed in illuminated digits. (See simplified diagram of circuitry.)

Jan 1, 1975

By Laird Crocker

A goal of the Federal Bureau of Mines is to minimize the undersirable environmental conflicts and impacts associated with mineral processing operations. To help reach this goal the Bureau operated a citrate-process pilot plant for the removal of sulfur dioxide from lead smelter sintering machine waste gases to test the process. The process uses a carboxylate solution such as citric acid to absorb sulfur dioxide from waste gases. The absorbed sulfur dioxide is subsequently reacted with hydrogen sulfide to precipitate sulfur and regenerate the solution for recycle. Nominal capacity of the pilot plant was 1,000 scfm of 0.5 vol-pct sulfur dioxide gas. The pilot plant was operated for over 5,400 hr and produced about 55 net tons of sulfur. The operation demonstrated that (1) 99 pct of the sulfur dioxide could be removed from lead smelter sintering machining waste gases containing from 0.1 to 0.6 vol-pct sulfur dioxide, (2) sulfur precipitation and solution regeneration with hydrogen sulfide in conventional stirred vessels was readily controlled, (3) precipitated sulfur could be continuously recovered as a 99.S-pct-pure product by flotation and melting, and (4) 78 dry-vol-pct hydrogen sulfide gas could be produced from pilot-plant product sulfur, natural gas, and steam.

Jan 1, 1979

By G. S. Scott

In the course of the Bureau of Mines investigation relative to the causes, behavior, and control of anthracite-mine fires, attention was directed toward the correlation between the temperature of oxidation and the gaseous oxidation products in the range of temperatures between 100° and 350°C4/. These tests, made on a high-grade anthracite to determine the amount of oxygen consumed and the mounts of carbon dioxide, carbon monoxide, hydrogen and methane evolved when air was passed through samples of the anthracite at various elevated temperatures, showed that the gases evolved and their relative proportions vary with temperature, constitute a means for determining the probable temperature of the anthracite, and thus permit detection of incipient heating beers dangerous fire hazard exists. As the relationships mentioned are affected somewhat by the amount of previous oxidation of the coal, it was deemed desirable to know to what extent they might vary owing to this cause. It was also considered desirable to have a means for estimating the extent of oxidation from the gas analysis, as this would permit a more accurate estimate of probable temperature. Finally, it seemed desirable to know how much the composition of coal might vary over an extended period of oxidation, since this was previously suggested5/ as a possible means for estimating the probable maximum oxidation temperature to which a sample of coal had been subjected.

Jan 1, 1940

By Nutter R. S.

A methodology has been developed for qualitative safety hazard evaluation and quantitative reliability analysis of mine monitoring and control systems. Detailed application of these techniques were made to two commercial monitor/control systems and to a West Virginia University distributed microprocessor-based system. A controlled environmental test was conducted on a set of one of the commercial system's outstations. A software reliability evaluation methodology was also developed and applied.

Jan 1, 1982

By I. L. Nichols

The Bureau of Mines is investigating vanadium recovery from various domestic resources. A low-grade carnotite ore sample containing 0.34 pct V20S and 0.04 pct U30S was leached, and the results were compared with those of similar leach tests using a mill-grade sample containing 1.26 pct V205 and 0.19 pct U308. Experiments on the two ore samples included agitation leaching, pugging, salt-roast leaching, and autoclave leaching. None of the leaching methods investigated showed any significant advantage over another except autoclaving, which reduced the leach time but at the expense of greater acid consumption. Typical of the experimental results attained are the data gathered from the agitation leaching tests. Agitation leaching of the mill-grade ore with 100 lb/ton H2S04 resulted in extractions of 94 pct U308 and 33 pct V205. To increase the vanadium extraction from 33 to 91 pct required concentrations of 300 lb/ton H2S04 and 10 lb/ton NaC103. Complementary agitation leach tests on the low-grade ore required 200 lb/ton H2S04 to extract 94 pct U308, and 300 lb/ton H2S04 and 10 lb/ton NaC103 to extract 90 pct V205.

Jan 1, 1983

By W. M. Myers

Jet is a substance of organic origin and has been defined by the U. S. Geological Survey as a "dense black lignite, taking a good polish, and sometimes used for jewelry". Jet is characterized by the lustrous, intense black surface it displays when polished. It is due to this property that the expression "jet black" is so commonly used to imply intense blackness.

Jan 1, 1923

By J. D. Dixon

This Bureau of Mines report describes a technique for determining the confining pressures that must be provided for stabilizing underground openings in incompetent rock. The technique is adapted for use with a nonlinear finite-element computer code, NONSAP, to obtain stabilization pressures for linear or nonlinear stress distributions in the rock media around the excavation. This analysis permits a point-wise calculation of active rock pressures that depend on the values of shear stress and strength along the excavation surface. The approach is applied to the solution of several sample problems. The results show that both the magnitude and the distribution of stabilizing confining pressures are significantly influenced by rock and joint strengths, joint orientation, and biaxial nature of the load field.

Jan 1, 1976

By D. Harrington

The experience of the past 2 years has demonstrated clearly that mine explosions with heavy loss of life can be prevented. The investigations of the Safety Division of the United States Bureau of Mines disclose that during the fiscal year 1934 there were only 28 deaths from mine explosions in the United States, and during the fiscal year 1935 there were 54 deaths, a very favorable reduction when compared with an average death toll of 265 from this cause during the 20-year period prior to 1929. Although the frequency of occurrence of explosions has not decreased greatly during the past 7 years, there has been a marked decrease in severity, indicating that the coal-mining industry is taking more effective precautions to prevent the spread of explosions. A number of large coal-producing States, which in past years have experienced numerous disastrous explosions, have been free from such disasters for continuous periods of as much as 5 years or even longer. A study of several hundred mine explosions occurring in the United States during the past 10 years or more indicates that the factors mainly responsible for these explosions are inadequate or defective ventilation and disregard of the hazards from explosive gas. Both of these factors are subject to control, and if controlled it is safe to say that deaths from explosions would be reduced to a negligible number as relatively few explosions are now initiated by dust.

Jan 1, 1936

By A. G. Galaitsis

This report summarizes the work performed under the USBM Contract No. J0245001. The purpose of this work was to expand and improve the scope and accuracy of the method developed under USBM Contract No. J0113056 for the prediction of the number of overexposed workers in the mining industry. A significant portion of the noise data were acquired during mine visits-that took place in the-course of this contract. These data were obtained with time-resolved dosimeters which among other things store a time history of the sampled noise for an eight hour work period. The remainder of the noise data have been obtained from MSHA files and from other BoM-sponsored projects. The report reviews the prediction model, discusses the model's assumptions and approximations, describes the function of the developed software, offers typical examples on the use of the software and includes plots of the newly acquired noise data records.

Jan 1, 1986

By David S. Yantek

Miners in underground coal mines experience prolonged exposure to high noise levels, often with A-weighted sound levels in excess of 90 dB. Field tests have shown that the continuous miner conveyor is a dominant noise source. This paper will identify the most significant noise-radiating surfaces on the continuous miner tail section using vibration levels and surface areas to estimate the sound power levels of each surface. In addition, using five test cases, this study will examine the effects of three engineering noise controls on the surface-averaged vibration levels and average sound levels measured with four microphones located two meters from the tail section. The noise-radiating surfaces of the conveyor’s tail section include the top and bottom decks, the sideboards, and the flex plates. Emphasis is placed on the changes in the estimated sound power levels in the 500 – 2500 Hz 1/3-octave bands since this frequency range accounts for 80-85% of the sound energy near the tail section. The results show that the bottom deck is the most significant noise radiator for the untreated miner. Installing a coated bottom deck reduces the estimated sound power level radiated from the bottom deck by 11 dB and the average sound level by 2 dB. Using a coated tail roller results in reductions of the estimated sound power levels for individual components from 1 to 4 dBand reduces the average sound level by 2 dB. Coating the slide plate has little effect on both the estimated radiated sound power levels and the average sound level. The test results indicate that modifications that reduce flex plate vibration and reduce energy transfer from the tail roller into the tail section will be effective in reducing noise when combined with a coated tail roller and coated return deck.

By G. L. Gates

The waters used to waterflood the Wilmington oilfield were studied by the Bureau of Mines, in cooperation with the city of Long Beach, Calif. Increases in the pressure of the injection wells indicated that they were being plugged by materials suspended in the waters. This study was made to identify the suspended materials, determine their origin, and find methods of preventing their formation. The suspended oil-coated materials were iron sulfide, barium sulfate, calcium carbonate, clay, and sand (or silica). Results indicated that the sulfide, which was as high as 90 milligrams per liter, was the product of sulfate-reducing bacteria. The injection of ocean water increased the sulfate content of the waters in the petroleum reservoirs from 3 to 250 milligrams per liter, thereby furnishing sulfate for growth of the bacteria. The waters were supersaturated with barium sulfate. Laboratory tests showed that sulfide could be removed from the waters by adding iron at a cost of 1 to 2 mills per barrel. The solubility of iron sulfide and calcium orthophosphate in the injection waters was also determined.

Jan 1, 1975

The objective of this study was two-fold: 1. To perform a world literature search pertinent to the analysis, selection and design of hoisting systems and their components and to codify the search into a literature compendium. The search resulted in a technical data file of over 1500 hard copy items. The compendium index was also suitable for establishing a comprehensive computer-loaded data base on the subject. 2. To develop a comprehensive system of guidelines to cover salient aspects of analysis, selection and design of electrical, mechanical and structural components of a hoisting system with a view to establish parameters for maximum safety and efficiency of operation, installation and revision of the system. 3. (a) In-shaft equipment design and specification criteria are considered as they influence guideline preparation. (b) A comprehensive review of hoist electric drives and controls as applied to mine hoists is set forth with special reference to duty cycle calculations and their effect on electrical component selection.

Jan 1, 1988

By Max J. Spendlove

The secondary copper industry is comprised of numerous enterprises which collectively employ many of the recovery and refining processes now used in primary plants as well as many other processes that are unique to the industry. Effective methods are used for identifying and segregating all types of scrap according to widely accepted standard classifications. Segregated scrap and waste materials usually require some preliminary processing to remove both valuable and deleterious associated constituents. Smelting, melting, alloying, and pyrorefining are common methods used for producing secondary metal, but operating techniques usually differ from primary metal operations because of the difference in physical and chemical properties of the respective raw materials. Some copper scrap is converted to copper chemicals rather than to refined metals or alloys. Recovery efficiencies of all processes are reasonably high, and the quality of products meets rigid specifications.

Jan 1, 1961

By Anthony E. Szczuka

The purpose of this design note is to document the data that has been received from manufacturers, coal companies, training centers, government agencies, etc., that pertains to the completion of the Concept Feasibility Study For Training Equipment Designed to Improve Coal Productivity. Revision A documents additional data that has been received. ACKNOWLEDGEMENTS We wish to express our appreciation to the companies, mines, government agencies, unions, and contractor agencies listed herein that furnished the documented data. In most cases, it was furnished willingly and free of charge. In the few cases where the data was purchased, MDEC IRAD funds were used.

Jan 1, 1976

By F. D. DeVaney

Manganese-bearing deposits f the Leadville, Colo., district are of two distinct types. Manganosiderite, a combined or intimately mixed ferrous and manganous carbonate, occurs in unaltered zones as the predominant mineral. From 50 feet below the surface to as deep as 900 feet, psilomelane and wad, both black manganese oxide minerals, are found in intimate contact with hematite and limonite. A typical analysis of the black oxide ore shows 20.08 percent Fe, 18.64 percent Mn, 15.91 percent insoluble, 14.91 percent moisture, 0.94 percent Zn, and 2.13 percent Pb. A considerable tonnage of the oxide ore has been mined for production of spiegeleisen and for other purposes.

Jan 1, 1940

By F. D. DeVaney

Manganese-bearing deposits of the Leadville, Colo. district are of two distinct types. Mangano siderite, a combined or intimately mixed ferrous and manganous carbonate, occurs in unaltered zones as the predominant mineral. From 50 feet below the surface to as deep as 800 feet, psilomelane and wad, both black manganese oxide minerals, are found in intimate contact with hematite and limonite. A typical analysis of the black oxide ore shows 20.08 percent Fe, 19.64 percent Mn, 15.91 percent insoluble, 14.91 percent moisture, 0.94 percent Zn, and 2.13 percent Pb. A considerable tonnage of the oxide ore has been mined for production of spiegeleisen and for other purposes.

Jan 1, 1940