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By Walter D. Holland

This document is one of a series of instruction guides developed to help instructors present health and safety training courses to workers in the metal and nonmetal mining industry. This course is intended to provide above ground metal and nonmetal mining employees with training which will assist them in performing their work safely and healthfully. A document entitled, "Airborne Contaminants in Above Ground Metal and Nonmetal Mining and Processing Work Areas," is used as a manual for the students during the course. The unique features of the teaching guide are thumb rules for recognizing hazardous situations, candidate contamin¬ants for each work area and descriptions of control devices and work procedures.

Jan 1, 1977

By Thomas M. Kohler, Gerald L. Finfinger, Gregory M. Molinda

The Bureau of Mines has completed an investigation of the effectiveness of methane drainage in the Lower Sunnyside Coalbed at Kaiser Steel Corp.'s Sunnyside No. 1 Mine in Utah. Most of the previous at- tempts to drain methane gas using long horizontal holes were conducted in the Eastern Coal Province. From the high degree of success realized in these efforts and the large body of knowledge gained from associated research, it seemed natural to extend the technology to western coalfields. Previous work had indicated that properties affecting gas drainage were variable in the Sunnyside Coalbed. In an attempt to characterize these properties, four degasification holes were drilled from the out- side entries of an advancing section. The holes were drilled to lengths of 780, 1,680, 1,315, and 1,047 ft and produced initial flow rates of 50,000, 180,000, 340,000, and 240,000 f t3/d, respectively. A total of over 300 million f t3 of commercial-quality gas has been removed from the Sunnyside Coalbed. The four holes have reduced face emissions by 78 pct.

Jan 1, 1986

By Laxman S. Sundae

Laboratory tests were conducted at the U.S. Bureau of Mines to determine the effects of roof-bolt drilling parameters on penetration rate in sandstone using tungsten carbide alloy (WC-Co) and polycrystalline diamond compact (PDC) drill bits. During the tests, water pressure of 552 kPa was found to be adequate for removing the cuttings from the tops of drill holes. Test results show that for both types of bits, penetration rate increased when thrust was raised from 227 to 1,588 kg. When water pressure rose from 554± 120 to 1,344±350 kPa, the effect on penetration rate was not significantly different. Conventional WC-Co bits became dull when one or two holes were drilled, after which the penetration rate dropped dramatically. Microscopic examination shows that the cutting edges of PDC bits also become somewhat dull, but at a much lesser rate than WC-Co tips. Microscopic examination also reveals that the wear mechanism of WC-Co and PDC bits is quite different, which may explain the longer life of the PDC bits.

Jan 1, 2010

By A. L. Engel

This report is a compilation of results of brief preliminary tests on sulfide ores that contained gold and silver and, in some cases base metals. It is a companion paper to a recent similar report on oxide ores. Simple treatment methods employing the least possible equipment sometimes produce satisfactory results on marginal ores and in small-scale operations. Investigations of typical ores from newly discovered or recently explored mining districts have been made in continuation of a long-established part of the hydrometallurgical and ore-dressing program of the Reno station, Bureau of Mines. The purpose of such investigations is to encourage the search for and development of mineral resources and particularly to assist in the economical exploitation of low-grade and marginal ores as well as the conservation and recovery .of values in products that were discarded from former operations because of inability to treat them profitably. Several of these investigations have been limited to preliminary tests of samples from prospecting operations, whereas same involved samples of old dumps or tailings piles. The test work in these cases was not extensive enough to warrant publication as individual reports, but is of considerable interest inasmuch as it indicates the possibilities as well as the limitations of treating the respective materials. The samples were representative of the districts from which they wore obtained, so this information should be helpful in the future development of these districts.

Jan 1, 1951

By Foster Fraas

This Bureau of Mines report describes a method for separating minerals at magnetic susceptibilities within the diamagnetic susceptibility range. The maximum feed rate varies directly with the square root of the lower limit of permissible susceptibility, while the lower limit of permissible susceptibility varies inversely as the square of the magnetic field strength. Minerals may be separated at particle sizes smaller than possible on conventional dry-type magnetic separators.

Jan 1, 1969

By John C. Machisak

INJURY data and experience, with related employment statistics, at coal mines in the United States for 1958 are presented in this publication under the following general sections: (A) General injury experience: Tables 1 to 6: Current data on number of injuries, degree of injury, frequency and severity rates, average severity, and related employment and production data by work location. (B) Selected injury experience: Tables 7 to 38: Current data on principal agencies of injuries, distribution of injuries by part of body injured, days of disability, extent of hand and machine loading, experience by employment and production groups, and various other operating factors and physical conditions related to the occurrence of injuries at the Nation's coal mines. (C) Injury experience by States: Tables 39 to 43: Current data on injuries, their causes, rates of occurrence and severity; employment and production data by work location, by States. (D) Major disasters: Table 44: Data on major disasters from 1949 to 1958. A major disaster is defined as a single accident in which, or as a result of which, five persons or more are killed instantly or die at any time thereafter. (E) Historical coal-mine-fatality experience: Tables 45 to 49: Data on fatalities and their causes at bituminous coal, lignite, and anthracite mines from the earliest records through 1958.

Jan 1, 1961

By William R. Roy

Seven coal-related waste samples (mining, cleaning, and gasification) were characterized chemically and mineralogically. Laboratory extracts of each sample, using a variety of different extraction methods, were used in both acute and chronic bioassays. A coal slurry sample (coarse fraction) and two coal cleaning refuse samples were chemically and mineralogically similar, and generated acidic water-waste systems, both in the laboratory and in the field. Acidic laboratory extracts and field samples of acid mine drainage in the area where the solid samples were collected, tended to be in equilibrium with some type of CaSO4 phase and with maghemite. The chemical composition of the extracts was sensitive to the method used to generate the extracts, but generally had the same prevalent chemical character as the field samples. The acidic wastes contain appreciable quantities of soluble Al, Mn, Ni, SO4, and Zn as indicated by both laboratory extraction and field data. Long-term extractions suggest that some constituents (Al, Fe, SO4) continued to be released by the acidic wastes after 22 weeks with no apparent associated change in pH. Two mine spoil samples, essentially shale, tended to generate water-waste systems that were neutral in pH and consequently released lower quantities tit potential pollutants than the acid wastes. The gasification residue was compositionally similar to coal-fired power plant slag and fly ash and generated moderately alkaline extracts with low concentration of soluble potentially toxic constituents. All of the solid wastes contained a variety of organic compounds, many of which are on the EPA Priority Pollutant List. However, these compounds were essentially insoluble in aqueous media. Each extract was tested for acute toxicity with tour species of freshwater aquatic organisms; green sunfish (Lepomis cyanellus), fathead minnow (Pimephales promelas), a crustacean (Daphnia magna), and a snail (Physa anatina). The extracts of the two mine spoil samples and of the gasification residue were not toxic to any of the organisms while the extracts from the acidic refuse and slurry samples were acutely toxic to all of the organisms. For all cases, pH was significantly correlated to mortality while Al, Fe, Mn, Ni, and Zn were significantly correlated to mortality in specific instances. Data from 96-hour LC-50 determinations showed that dilutions up to 1:1000 were necessary to eliminate mortality. The most toxic extracts were those with the lowest pH which necessitated the largest amounts of dilution to eliminate mortality. Chronic bioassays with the same test organisms were investigated with leachate samples from a relatively unweathered refuse sample and an older, more weathered refuse sample. The unweathered refuse sample generated a leachate that was acutely toxic while the leachate from the weathered refuse sample was not acutely toxic. No detrimental chronic effects were noted in organisms exposed to dilutions of the non-toxic leachate while low concentrations of the acutely toxic leachate produced lower hatchability for the Lepomis cyanellus and Pimephales promelas eggs, increased mortality with chronic exposure for Lepomis cyanellus, Daphnia, Physa, and reduced weight gain for Physa. Dilutions of a toxic, high-Fe leachate resulted in the precipitation of ferric hydroxide that was implicated as the major causative factor accounting for the physical and physiological toxic effects exhibited by all of the test organisms in these acutely sublethal concentrations. The toxicity of this leachate demonstrates the potential effects that these types of wastes can have on the aquatic ecosystem if they enter a receiving water in a natural setting.

Jan 1, 1984

By R. L. Solmer

During 1959-61, the Bureau of Mines investigated the strain and deformation induced in rock and concrete linings around mine openings by retreat panel caving at the Climax Molybdenum mine. Two concrete-lined slusher drifts on the Phillipson level of the mine were instrumented with both electrical strain gages and extensometers. Changes in strain and deformation were recorded over an 18-month period during the undercutting and caving of the mining panel. General agreement was found between the strain and deformation measurements and the hypothesis that the vertical component of the stress field on the openings is almost completely removed by undercutting. This phenomenon is a possible explanation for the structural failures that occur in the slusher drifts during the undercutting cycle.

Jan 1, 1965

By D. K. Deardorff, Laurance L. Oden, H. Kato, M. I. Copeland

The equilibrium relationship of hafnium and tantalum was studied to facilitate alloy and property investigations . The data obtained are presented graphically as the equilibrium diagram . Alloys were prepared from high - purity components by nonconsumabletungsten- electrode arc melting . Data for the equilibrium diagram were obtained by optical pyrometry , metallography , X- ray diffraction of heat treated specimens , X- ray diffraction using a high- temperature camera , and differential thermal analysis . During the investigations , a casting apparatus was constructed , and the existing melting - point apparatus was improved . The bcc allotrope of hafnium forms a continuous series of solid solutions , called beta , with tantalum which exhibit a minimum melting point at 20 wt pct tantalum and 2,110 ° C. At 24 wt pct tantalum and 1,050 ° C , hafnium- rich beta decomposes in a monotectoid reaction to yield alpha and tantalum- rich beta . The monotectoid isotherm extends from 5.5 to 60 wt pct tantalum . The twophase region , in which hafnium- rich and tantalum- rich beta solid solutions are immiscible , rises to a maximum temperature of 1,265 ° C at 38 wt pct tantalum . The solubility of hafnium in tantalum decreases from 40 wt pct at the monotectoid temperature to 20 wt pct at 750 ° C.

Jan 1, 1964

By John E. Pahlman

The Bureau of Mines conducted column-leaching tests on 25 domestic Mn ores to determine the feasibility of extracting Mn by in situ or heap leaching with dissolved sulfur dioxide (S02) solutions. The ores tested were obtained from deposits in Arizona, Arkansas, California, Colorado. Maine, Minnesota, Nevada, and South Dakota. Dissolved S02 was found to be effective for leaching Mn; extractions greater than 90 pct were obtained with solution application rates of 1 mL/min from uncalcined, minus 2.5-plus 1.3-cm ore pieces. Leaching these ores with solutions containing only 5-wt-pct S02 and no added H2S04 resulted in Mn being selectively extracted over Fe except when Fe was present as goethite or siderite. Ca solubilization was inhibited by controlling the solution application rate (1 mL/min). The rate of leaching was found to be principally dependent upon the rate at which the leaching solution can penetrate the ore, since the solubilization of Mn upon contact with S02 was observed to be rapid. Despite low water permeabilities of the ores (as low as 10-2 to 10-4 darcy). greater than 90 pct of the Mn was extracted from even the largest ore pieces tested (approximately 10 cm in diameter). It appears, therefore. that leaching Mn opens up the pores, allowing penetration of the leach solution into the ore pieces.

Jan 1, 1988

By K. B. Rojiani

Surface mining activities disturb large tracts of land resulting in the potential for greatly increased downstream sediment loads. The Surface Mining Control and Reclamation Act of 1977 places increased emphasis on the protection of the environment from the adverse effects of surface mining operations. Surface mining activities must be planned to minimize disturbance to the hydrologic balance, erosion and sediment contributions to receiving streams. Sediment ponds must provide a sediment storage volume equal to the accumulated sediment volume from the drainage area as determined by the Universal Soil Loss Equation (USLE) or other empirical methods established by the regulatory authority. It has thus become extremely important for the mining industry to secure more accurate estimates of potential erosion losses and sediment yield. Accurate estimates of sediment yield are required for the planning, design and successful operation of sediment control systems such as detention ponds and other alternative control structures and for evaluating the effectiveness of land management practices. The principal soil loss prediction procedure available for use is the LISLE. The USLE procedure is inadequate for use in predicting soil loss from surface mine regions for a number of reasons. These include: 1. The USLE was developed to estimate average average annual loss from agricultural soils. It cannot predict accurately soil loss for specific storm events. In surface mine regions a major portion of the soil loss occurs during the initial six months to one year of active mining. Accurate estimates of soil loss over short periods are thus required for the design of control structures. 2. The slope length and gradient factors used in the USLE were obtained from data or cropland having slopes ranging

Jan 1, 1983

By H. Kenworthy

The objective of this investigation was to evaluate the technical feasibility of smelting certain low-grade domestic iron ores in an electric furnace. Laboratory-scale experiments showed that a high recovery of iron in the form of pig iron can be obtained from east Texas ores containing less than 25 percent iron. The pig iron was amenable to standard-or electric-furnace-refining methods for producing steel. Car-bon, silicon, and phosphorus were the primary impurities removed in refining. Overall recoveries of iron as pig iron exceeded 95 percent, in contrast with commercial mineral-dressing recoveries on these particular ores of 50 percent of the iron as a 45-to 50-percent iron concentrate.

Jan 1, 1958

By H. C. Ko

Calorimetric determinations of low-temperature heat capacities and the standard enthalpy of formation were made by the Bureau of Mines for aluminum sulfide, A12S3. The standard entropy (S°), enthalpy of formation (?Hf°), and calculated Gibbs energy of formation (?Gf°) at 298.15 K are 27.93±0.05 call deg-mole, -155.6±0.9 kcal/mole, and -153.0±1.0 kcal/mole, respectively.

Jan 1, 1976

By C. W. Vierrether

Tailings from the Pea Ridge iron mine contain significant amounts of apatite, which has rare-earth element values associated with it. In association with the recovery of rare-earth minerals as a secondary resource, the U.S. Bureau of Mines conducted an investigation on the recover ability of the rare-earth minerals from these tailings. The mill tailings were subjected to a phosphate flotation to separate the apatite from other constituents. More than 70-pct recovery of the rare-earth values was achieved. Based on mineralogical characterization and prior analysis of rare-earth-bearing breccia pipe material at Pea Ridge, it is proposed that processing this phosphate concentrate on a vanner table would yield up to a 95-pct recovery of the rare earths in the concentrate, with the apatite reporting to the tailings. Intensive ore microscopy studies of the original tailings to the flotation products led to the identification of monazite, xenotime, and rare-earth-enriched apatite as the major rare-earth-bearing minerals in the tailings.

Jan 1, 2010

By Fred D. DeVaney

Copper sulphate is a common flotation reagent for blonde ores. Metallic iron also is present in the mill circuit, and a reaction between the iron and the salt would be in accord with well-known chemistry. The abundance of metallic iron in a flotation food may be noted by even perfunctory examination. First of all the mine contributes metallic iron, then the coarse-crushing machines add their share, and finally the fine-grinding medium its portion. If the grinding is with cast-iron balls the amount of metallics is greater than when steel is used. Thus it, is that much more metallic iron is present than would be indicated by noting the ball consumption. An estimate that the total amount of metallics is twice that supplied by the balls and liners might not be far amiss. That copper sulphate plates out on iron in an acid solution is well known, but since flotation is practiced commonly in solutions where acid has not been added this reaction has not been given sufficient thought.

Jan 1, 1929

By Gerald T. Homce

A system capable of monitoring mine electrical power systems and detecting impending component .failure could significantly improve power system safety and reduce unscheduled equipment downtime. Such monitoring would require a method of evaluating electrical parameters, calculated from terminal values, for indications of component deterioration. The U.S. Bureau of Mines has targeted electrical failure of squirrel cage induction motors and examined the use of mathematical models to aid in this evaluation. The initial stage of this work is complete, and has produced polynomial networks called adaptive learning networks (ALN's) that can detect and quantify winding insulation leakage simulated on laboratory motors. In this modeling process, empirical data from laboratory motors were used to select the electrical parameters most significant for assessing? motor conditions, and mathematical expressions relating these parameters to simulated deterioration were formed. ALN's developed thus far can process readily measured motor terminal information and quantify power and current levels of laboratory-simulated leakage to within 1% and 3% of full load values, respectively, for motors in the 10-to 150-hp size range. The next stage of this research is validation of these ALN's for actual motor failures; this stage is currently underway, using accelerated life testing of laboratory motors.

Jan 1, 2010

By Barry W. Klein

The U.S. economy was considerably stronger in 1976 than in 1974 or 1975. Real gross national product (GNP) rose sharply in the first quarter of 1976 and then increased at a more moderate rate for the remainder of the year. The unemployment rate fell until June and then increased for moat of the remainder of the year, finishing at the same rate as it had started the year. The inflation rate continued to decline in 1976. Reasons for the relatively low rate (compared with those of 1974 and 1975) included small increases in food prices and only moderate increases in energy prices. Total U.S. output measured in terms of GNP increased 11.6% in 1976. Real GNP in 1972 constant dollars rose 6.2%. Inflation as measured by the implicit price deflator increased 5.1%. In real terms, gross private domestic investment for residential structures rose 22.7% in 1976 after declining 14.7%a in 1975; State and local Government expenditures increased 1.4% in 1976; and personal consumption expenditures for services rose 4.5%. The Federal Reserve Board (FRB) index of industrial production increased 10.2%.

Jan 1, 1978

By Oliver Q. Leone

Three electrorefining cells were designed to investigate various factors associated with the electrorefining of reject - grade titanium sponge . Operation of the cells provided information on cell design as well as on how design and operating variables affected the quality of the titanium product . A sodium chloride - titanium chloride electrolyte was used , and the electrolyte chambers had capacities ranging from 400 to 3,500 pounds of molten salt . Major factors investigated were electrolyte composition , temperature and useful life , effect of various cathode shapes and materials of construction , methods for removing cathode deposits , effect of current density and cell potential , and the mechanics of deposit growth and crystal morphology . One of the cells was in intermittent operation over a 4 - year period and produced 2 tons of refined titanium . A product with a hardness of 80 or less Bhn (Brinell hardness number ) was consistently and easily obtained . Some metal with a hardness of less than 60 Bhn was produced . In one of the cells in which the electrolyte was held at operating temperature with an internal heater an ac input of 25 kw maintained 3,500 pounds of electrolyte at 850 ° C , but with an external heater 35 kw was required to maintain 400 pounds at 850° C.

Jan 1, 1964

To address the safety of programmable electronics-based mining systems before this technology proliferates in the mining industry.

Jan 1, 1999

By R. V. Ramani, R. Bhaskar

"The control of respirable dust in mines has been given paramount importance due to the health and safety implications associated with fine dust. The understanding of the temporal and spatial behavior of dust has been recognized as essential for increasing the efficiencies of the existing control techniques and for developing new control strategies. Mining-related studies in this area are, in general, limited. They are also mostly experimental. Some mathematical and computer analyses have been attempted. In this paper, first a review of the mathematical studies performed in the last three decades in this area is presented. Second, a mathematical model for analyzing dust flow in mines is proposed. The model takes into account a number of factors affecting dust transport. It incorporates varying dust generation source strengths and dispersion, deposition, and coagulation of dust in mine airways. Finally, application areas for the model are discussed. A computer program based on the mathematical model has been developed. The program will output the dust concentration in the mine atmosphere as a function of time and distance from the source. The amount of dust deposited on the sides, roof, and floor of the airway is also determined.IntroductionAn airborne dust cloud is a complex system containing particles of varied size, density, shape and state of aggregation. The behavior of the particles is dependent on a number of complex physical mechanisms, often opposing in nature. The net interaction results in the ambient concentration. This size dependent behavior of particles contrasts with that of gases, an area quite widely studied.The term aerosol is used to describe clouds of microscopic and submicroscopic particles in air such as chemical smoke or particulate matter released from smoke stacks. An aerosol system can be regarded as an arbitrary element of volume filled with gas and suspended particles of possible highly variable physiochemical nature. The parameters that are used to describe an aerosol system include concentration, mass average velocity and particle mass and radius. In characterizing such systems, several assumptions are made. Among these is the assumption that particles are smooth, inert and rigid spheres. Again, for example, when the particles are in transport, the possibility of collision exists. As a result of the collision, the particles may coalesce to form larger particles. The probability of sticking is considered a known quantity (lady, 1970). In this paper, the application of the principles used in aerosol systems is explored for the study of the transport and deposition of fine coal dust in underground mines."

Jun 1, 1988