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By Jalna R. Zatko

Coal-clay waste slurries were dewatered in laboratory-and small-scale continuous tests by the Bureau of Mines using polyethylene oxide (PEO) as a flocculant. Dewatering from a nominal 7-wt-pct solids to over 50-wt-pct solids was accomplished using 0.5 lb of PEO per ton of feed in small-scale continuous tests. Parameters such as pH, initial solids content, and PEO concentrations were investigated. Water recovered from dewatering was reused as dilutant for PEO solutions.

Jan 1, 1982

By J. W. Paul

This report is the second of a series of papers on coal-mining methods and costs which are being prepared by the U. S. Bureau of Mines for the purpose of placing before those interested in the industry a knowledge of the mining methods employed in this particular mine, and cost data on the several operations pertaining to removing the coal from the face into the railroad cars at the tipple with economy and safety. The methods employed are influenced by the natural local conditions, with respect to the thickness of overburden, frequency of local "wants," and the means employed for roof support, and its control

Jan 1, 1929

By R. H. Bedford

"The El Dorado copper mine is situated in the foothill copper-zinc belt of California, which traverses the western slope of the Sierra Nevada with unusual persistence from Butte County to Kern County, a distance of more than 300 miles. Although this area contains such important past producers as the Penn mine, Union, and others, a great part of the current production has been derived from smaller properties, which depend largely on premium metal prices for economical operation. The El Dorado mine is in the latter group, which constitutes an important source of metal in a national emergency.Exploration by the Bureau of Mines by means of eight diamond-drill holes Indicated narrow, intermittent lenses of copper ore along structures boo feet in length. The copper occurs in massive sulfides composed of chalcopyrite, pyrite, pyrrhotite, and minor quantities of bernite. The sulfides have evidently replaced tuffs, which are interbedded with the Mariposa slates and shales.H. A. Weiler and Hal T. Hall, owners of the El Dorado copper property, requested an examination by the Bureau during the latter part of 1914. In December of that year an engineer of the Bureau of Mines visited the mine and recommended the project work undertaken. The purpose was to aid the owners in bringing the property into production of copper and zinc, which at that time was critically essential to the war industries.Complete factual data obtained by the exploration are embodied in this report.In its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G, Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. R. S. Dean, assistant director.Acknowledgment is made to A. O. Johnson, chief, Reno Division, Mining Branch, and Lowell B. Moon, chief, Mining Branch, for their aid and direction."

Jun 1, 1946

By Erie C. Donaldson

Gas-displacement tests were made in Berea Sandstone and Arbuckle Lime-stone cores to determine the relative permeabilities to gas, oil, and water for two-and three-phase dynamic systems. Three-phase relative permeabilities were obtained by displacing oil and water from the core with gas and measuring the flow rates of the three fluids simultaneously. It was found that relative permeabilities to fluids in a porous medium are affected by the saturation distributions of other fluids in the medium as well as by their own saturation distributions.

Jan 1, 1966

By Paul M. Tyler

The enormous deposits of greensand in New Jersey and elsewhere in the United States, many of them close to important octant industrial centers, constitute a perpetual challenge for research chemists to convert them into a commercial asset of national importance. Following the introduction of more concentrated fertilizers, comprising synthetic mixtures of more soluble salts, the quantity of greensand used directly upon the soil has diminished, but deposits of such material still have at least potential value locally for use not only as fertilizer but also as a water softener. An annotated bibliography of the already extensive Literature on greensand, virtually complete to about the end of 1929, has been issued by the Bureau of Mines3/, and the commercial aspects as well as the technology of greensand utilization are discussed in available publications, The purpose of the present circular, therefore, is merely to provide a brief outline of certain general essential considerations for use in appraising the potential value of a greensand deposit in any given locality.

Jan 1, 1934

By Eric R. Bauer

This Bureau of Mines manual is intended to provide a better understanding of ground movement and the technology available for measuring it, The manual deals with convergence, strata separation, lateral roof movement, stress, and support load in underground mines. The instruments that measure these ground control parameters are described in detail. Step-by-step procedures for selecting the appropriate instrument are presented, which consider such factors as approximate cost, installation procedures, data collection, and data interpretation; and an instrument selection worksheet is provided to facilitate the instrument selection process. Actual instrument case studies and a list of instrument suppliers are presented in the appendixes.

Jan 1, 1985

By D. H. Platt

Bauxite, the principal source of aluminum, has been mined from deposits in Saline and Pulaski Counties, Ark., since 1899; war needs have greatly stimulated production. Many of the ore deposits are basin-shaped and either outcrop or are covered by a shallow-depth overburden at their peripheries; these are mined by stripping and open-pit methods. When stripping becomes economically impracticable, incline shafts or slopes are sunk on the dips of the deposits, and underground mining is done on the retreat, using a room-and-pillar method.

Jan 1, 1945

By T. J. Williams

Researchers at the U.S. Bureau of Mines monitored rock mass response to mining of an experimental underhand longwall stope in Hecla Mining Co.'s LUCKY Friday Mine, Mullan, ID. This stope design, the Lucky Friday underhand longwall (LFUL), was proposed as a means of controlling rock bursting while also allowing increased mechanization of mining operations. Instruments were specifically manufactured to monitor three geomechanical factors (backfill performance, ramp stability, and rock mass response) that directly affect the success of stope design. Despite considerable difficulties with instrument installation and survival in the harsh mine environment, especially within the stope fill, sufficient information was collected to suggest that the LFUL method was successful in achieving project goals. This conclusion, in addition to favorable economic and operational evidence, led the mine to adopt the method throughout the mine. Indeed, this study and mining experience suggest that underhand longwall mining could be considered a feasible mining method for rock-burst-prone ground throughout the Coeur d'Alene District. Further Reports of Investigations (RI) in this series present in-depth analyses of the effects of backfill on rock bursting and calibration of a stope numerical model.

Jan 1, 2010

By C. H. Elder

A 5-hole pattern was drilled from the surface at a site near Oak Grove, Jefferson County, Ala., to degasify the gassy Mary Lee coal bed in advance of mining. Gas and water production was monitored for 1 year, 4 months to allow gas flow to stabilize fully. A thickened water stimulation treatment was designed and applied in one hole of the pattern to evaluate this degasification technique for the Mary Lee coalbed. A gas production rate of 70,000 fts/day after stimulation treatment indicates that the use of vertical boreholes coupled with hydraulic fracturing in advance of mining the Mary Lee coalbed would provide for more rapid degasification and could provide a possible source of natural gas.

Jan 1, 1974

By G. W. Jones

The operation of combustion engines of various types at high altitudes and other combustion processes at reduced pressures have made it desirable to determine limits of flammabilities -under these conditions. Experiments carried out by the Bureau of Mines have shown that although natural gas-air mixtures become more difficult to ignite as the pressure is reduced below atmospheric, with a suitable source of ignition the limits of flammability are as wide at 175 mm mercury absolute as they are at atmospheric pressure.

Jan 1, 1949

By H. E. Peterson

A study was undertaken by the Bureau of Mines to develop a simple, reliable test for field detection of selenium in rocks and soils. Two methods are described for qualitative detection of selenium, dependent upon its form of occurrence and the presence of interfering constituents in the sample. Both methods involve fusion of the sample in a test tube to form elemental selenium that will volatilize and condense as a red deposit on the cooler upper portion of the test tube. The methods are sensitive to 10 parts per million, (p.p.m.) equivalent to 0.001 percent, and can be made semiquantitative by using suitable standard samples. INTRODUCTION Although selenium is widely distributed in the United States, the known deposits are either so small or so low grade that they cannot be processed economically for selenium alone-4/ At present, commercial production is a byproduct of the smelting and refining of base-metal ores, particularly copper.5/ About 0.75 pound of selenium is recovered per ton of electrolytic copper, and small amounts are recovered by special treatment of assorted smelter dusts and fume products. Since selenium is a strategic metal in short supply, new sources are being sought by both Government and private interests.

Jan 1, 1957

By J. H. Johnson

The report references reports and publications from 1975 to the present related to diesel underground mine air quality research undertaken by Michigan Technological University. Research results obtained on this contract are summarized in 5 different sections as follows: Section 1 - Development of a Systematic Approach to Monitoring, Data Analysis, and Interpretation for Diesel Mine Air Quality Control, Section 2 - Experimental Evaluation of LHD On-Board Air Quality Control Systems, Section 3 - Development of a Portable Self-Contained LHD Tailpipe Emissions Measurement Apparatus for NO , N0, CO, CO , and Particulate Matter, Section 4 Quantitative Analysis of Diesel and Coal particulate Matter by Laser Raman Spectro¬scopy and Section 5 - Development and Application to Detector Tubes of a Laboratory Method to Assess Accuracy of Occupational Diesel Pollutant Concentration Measurements.

Jan 1, 1985

By A. D. Garman

This paper presents one of a series of digests of foreign mining legisla- tion and court, decisions which is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate mines in various foreign countries. This interpretation of the laws of Latin America has been prepared from the best available information in Washington, but is released subject to correction and amplification, if necessary, by the proper American diplomatic and consular officers, to whom it is being referred through the courtesy of the Department of State. Individual abstracts of the laws of each of the countries herein discussed have been prepared and published separately. This general summary is presented for the use of mining engineers and investors whose interests extend over the borders of a single country. It is also designed to bring out certain general principles of mining law and, so far as feasible, to indicate the trend of mining legislation in South and Central America. In order to gain perspective, the details of legislation are not com- pletely covered in this paper, but an effort has been made to bring out essential differences as well as points of similarity in the laws of the various countries. The course of legislation is first traced chronologically and the points discussed are then arranged in tables in somerhat greater detail. .Si. With a very few exceptions the existing mining legislation of Spanish America is a development, of the Spanish "Law Decree of Bases" (more briefly referr- ed to as the "Decree-Bases") of 1868. This in turn was influenced, particularly in its classification of minerals, by the French law of April 21, 1810.

Jul 1, 1930

By Thomas J. Peters

In 1978, the U.S. Bureau of Mines and the U.S. Geological Survey completed a joint mineral survey of the Chemise Mountain and King Range study areas as mandated by the Federal Land Policy and Management Act of 1916, Public Law 94-579. The U.S. Bureau of Mines examined all identified mineral prospects and deposits; the results of these examinations are included in this report. The U.S. Geological Survey studied the regional geology, geochemistry, and geophysics; the results of these studies are available in USGS Map MF-1196. No mineral resources were identified in either the Chemise Mountain or King Range study areas; however, a high-grade silver and base-metal occurrence, and minor manganese resources were identified in between the two study areas, within the King Range Conservation Area. The only mining activity in either area was a placer gold prospect on Honeydew creek in the northeastern part of the King Range study area. Three samples from this prospect contained no gold. The Chemise Mountain and King Range study areas are in a mountainous region along the coast of northern California, 230 road miles north of San Francisco, and 70 miles south of Eureka by way of U.S. Highway 101, through Garberville and Redway. The Chemise Mountain study area consists of 3,941 acres; it includes the 2,598-ft Chemise Mountain, and the cliff-lined seacoast southeast of Shelter Cove. a resort and fishing village. The King Range study area consists of 39.764 acres northwest of Shelter Cove, and includes the northwest-trending King Range with elevations above 4,000 ft. The Chemise and King Range study areas are underlain by deep-water marine sandstones, shales, and minor pillow basalts of the Late Cretaceous and early Tertiary Franciscan Subduction Complex. Mineral production was 1,650 tons of manganese ore within a manganiferous bed overlying pillow basalt at the Queen Peak mine southeast of the King Range study area. However, no significant manganese resources were found in the Queen Peak area. The Point Delgada area, directly south of the King Range study area, has prospects with high grade copper, lead. silver, and zinc. Exposures are inadequate to estimate resources; however, the metals may be associated with Franciscan volcanism (volcanogenic). The Chemise and King Range study areas may contain similar economic silver-rich, base-metal deposits.

Jan 1, 1992

By Richard W. Watson

Card-gap and projectile impact sensitivity data are presented for a wide variety of explosive compositions tested at the Bureau of Mines in more or less standard test geometries. The results of both tests are in good agreement in that they provide the same sensitivity ordering for different subclasses of explosives. Least sensitive were homogeneous liquids that did not exhibit a tendency to undergo low-velocity detonation, ammonium nitrate-fuel oil, and most cast military explosives. Of intermediate sensitivity were pressed and powdered military explosives, cast pentolite, permissible and non- permissible water-based explosives, and one commercial two-component explosive. The most sensitive were permissible and nonpermissible dynamites and explosives susceptible to low-velocity detonation.

Jan 1, 1973

In spite of advances in measurement techniques and an explosive increase in the volume of research, our understanding of human strength remains in its introductory stages. It is clear that muscle strength is a highly complex and variable function that depends on a large number of factors. It is not surprising, therefore, that large differences in strength exist not only between individuals, but even within the same individual tested repeatedly on a given piece of equipment. The issue is compounded by the fact that correlations of strength among different muscle groups in the same individual are generally low, and tests of isometric strength do not necessarily reflect the strength an individual might exhibit in a dynamic test. As a result of these and other influences, great care needs to be exercised in designing, evaluating, reporting, and interpreting muscular strength assessments. Traditionally, tests of muscular strength were in the domain of the orthopaedist, physical therapist, and exercise physiologist. Such tests are also an important tool for the ergonomist, however, because of the high strength demands on workers in manual materials-handling tasks. In some cases, task demands may approach or even exceed the strength that an individual is voluntarily willing to exert in a test of strength. In such cases, evidence suggests that the likelihood of injury is significantly greater than when the task demands lie well within an individual's strength capacity. Because the relationship among strength capabilities, job demands, and musculoskeletal injury has been established, it is apparent that tests of muscular strength may benefit the ergonomist both in designing jobs and in ensuring that individuals have sufficient strength to safely perform physically demanding jobs. Several strength assessment techniques have been employed for these purposes, each possessing unique characteristics and applicability to job design and worker selection procedures. Our main purpose has been to elucidate these strengths and weaknesses, so that tests of strength may be properly applied in designing jobs and selecting workers. One of the crucial points we have emphasized is that any test of strength used in job design or worker selection must be directly related to the demands of the job.(1) For example, if an occupational lifting task has a high dynamic component, a test of isometric strength is not likely to provide the data necessary for proper design of the job. Of course, dynamic strength tests would also be misapplied in assessing a job requiring isometric exertions. Another potential pitfall is using tests of strength on isolated muscle groups and assuming that they are indicative of whole-body strength. For example, one might mistakenly assume that dynamic trunk extension strength represents a person's capability to perform a lifting task. However, an individual's lifting capacity may be entirely unrelated to trunk extension strength. It may, instead, be limited by an individual's arm or leg strength, depending on the task being performed. A final point on strength assessment should be made. An individual's strength capability cannot be considered a fixed human attribute. Strength training regimens can increase an individual's strength capability by 30%-40%. Whether

Jan 1, 1998

By Michael J. Magyar

The Federal Bureau of Mines has developed a hydrametallurgical method to recover aluminum, aluminum oxide, and fluxing salts from aluminum salt slags. The slag is leached with water at room temperature to produce a saturated brine slurry. Screening of the slurry yields an aluminum-rich fraction that can be returned to the dross furnace. The remaining slurry is vacuum filtered, yielding a clear brine solution and an aluminum oxide filter cake. Evaporation of the clear filtrate produces a high-purity fluxing salt for reuse in the dross furnace. Over 80 pct of the metallic aluminum is recovered in the aluminum-rich oversize fraction, while essentially all the fluxing salts are recovered by evaporation. This report contains the final results of an investigation on a process research unit scale, an economic evaluation of the method, and recommendations to further improve the process.

Jan 1, 1979

1. PURPOSE The Temporary Face Support System (TFSS) consisting of beams, posts and carrying-emplacing equipment was developed to provide temporary supports between the working face and the permanent roof supports. 2. GENERAL DESCRIPTION The system consists of: ? A Beam And Post Carrier And Deployer (BAPCAD), a self-propelled machine that carries as well as emplaces the beam-and-post sets. ? Lightweight mechanically self-deploying posts designed to safely support a load of 10,000 pounds each. ? Lightweight constant strength beams (bars) capable of sustaining an approximate equally distributed load of 8500 pounds. Note. All referenced figures and drawings are found at the back of this manual.

Jan 1, 1980

By R. V. Ramani, R. Srikanth, R. Zhao

"A two-pan study was conducted to understand the factors affecting respirable dust generation potential or dustiness of coal seams. In the first part, the data from three prior comprehensive laboratory studies was analyzed to establish quantitative relationships between respirable dust generation potential and coal characteristics. This analysis indicates that respirable dust generation rate is positively correlated with Hardgrove Grindability Index (HGI), fuel ratio (fixed carbon/volatile matter), Vitrinite Reflectance (VR), and Level of Organic Metamorphism (LOM). In the second part, specially-designed single breakage experiments were conducted to determine the primary dust generation potential of 17 coal samples obtained from four continuous miner sections, three longwall sections, and the Penn State Coal Data Bank. The single breakage study indicates that primary dust generation rate is positively correlated with fixed carbon content, fuel ratio (fixed carbon/volatile matter), VR, and LOM. Since VR and LOM are strongly influenced by the process of coalification, differences in respirable dust generation rates in different coal seams may be explained by the thermal metamorphism of sedimentary organic matter during subsurface burial.Mineral particles in the range of one to five microns, if inhaled in sufficient amounts, lead to a number of lung diseases generally referred to as pneumoconiosis. A priori knowledge of the mechanisms and rates of fine particle generation during mining can aid in the development of more effective technology for controlling primary dust generation. Unfortunately, the data and knowledge currently available are not adequate for this purpose. In fact, a committee of the National Academy of Sciences on the measurement and control of dust concluded that the knowledge of the fundamental mechanisms by which coal mine dust is generated and a part of it is entrained in the mine atmosphere as respirable dust is not sufficient to clarify, let alone control, the processes involved (Anon., 1980). Under a research contract from the U.S. Bureau of Mines, Stecklein et al. (1982) have identified a number of fundamental research issues for understanding the coal fragmentation and entrainment processes.Reduction of dust generation is the best means of control since fine particles are difficult to control once they become airborne. Therefore, considerable research efforts have been directed to understand the factors influencing dust generation and entrainment, including machine design, water sprays, and ventilation. Laboratory studies have been conducted on the mechanical action of bits and machine power requirements (Evans and Pomeroy, 1966; Roepke, 1984). Since the physical characteristics of coal play an important role in the process of breakage, a number of laboratory studies have been conducted to study the relationship between coal characteristics and respirable dust generation (Baafi, 1977; Moore, 1986; Polat, 1990; Thakur, 1971). Several studies have been conducted on the relationships between coal characteristics and airborne dust concentrations (Hamilton and Knight, 1958; Khair and Xu, 1991; Organiscak and Page, 1993; Page et al., 1993). A limited number of studies have also been conducted on the relationships between coal characteristics and airborne dust concentrations in mines (Organiscak et al., 1990). Yet, no reliable method has been developed to rank coal seams according to their respirable dust generation potential. The conclusions derived from previous studies can be summarized as follows:"

Dec 1, 1996

By S. H. Brooks

"IntroductionThis preliminary report deals with the effect of oxygen pressure on the ignition temperature and combustibility of oils, it is the third of a series which will present the results of an investigation being made by the Bureau of Mines, on oxygen-oil explosions. The purpose of this research is to obtain technical data that will serve as a basis for safety precautions general outline of the problem has been given in the first report (Serial 2507).The present experiments have resulted in (1) a method for determining spontaneous ignition points of oils in an atmospheric of oxygen under pressure; and (2) the determination of these ignition temperatures for three typical oils, one being an animal oil (sperm), one a vegetable oil (linseed), and one a mineral oil (""Moiloil A"").These experiments on explosibility of oil were performed in order to discover the general nature of the phenomenon, especially the order of magnitude of the temperature necessary for spontaneous explosion (120°C. and upwards) and the effect of pressure variation (negligible as regards ignition temperature but important in relation to the violence of the explosion). A continuation oftests should provide a basis for selecting the safest lubricants for high pressure compression of gases particularly air and oxygen; and should be of value when devising new specifications for lubricants, both in the government departments and the compressed-gas manufacturing industry."

Dec 1, 1923