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By M. A. Hammer

In this study by the Federal Bureau of Mines Pennsylvania anthracite from the Eastern Middle field was oxidized by concentrated nitric acid at steam-bath temperature for 24 to 1,000 hours. The quantitative data obtained include yields of nitric-acid soluble and insoluble products and the distribution of carbon and ash in each. The acid-insoluble residues were examined for solubility in aqueous sodium hydroxide. With a sodium hydroxide concentration of at least 1 normal, a portion of the residue could be extracted in the form of a true solution. With lower alkali concentrations, peptization occurred. Alkali solubility of the residue increased with length of oxidation. However, when expressed in percentages of original coal weight, the alkali solubility remained essentially constant after 192 hours of oxidation. This suggests that the alkali-soluble products are converted to acid-soluble products at the same rate as the original coal substance is converted to alkali-soluble material. Microscopic observations of the peptization of the acid-insoluble residues revealed a gross micellar physical structure. The action of nitric acid is apparently not restricted to the surface of a coal particle. The acid penetrates the particle through the pore structure, dissolving some of the ash and altering the bonds between the coal micelles. The bond alteration, as indicated by ultimate analyses, involves the physical and chemical adsorption of the components of nitric acid. Some of the altered bonds are not thermally stable; this instability is shown by the complete loss of peptizing ability when the acid-insoluble products are heated above 200° C. This loss is accompanied by the evolution of water, oxides of nitrogen, and hydrocyanic acid.

Jan 1, 1961

By G. W. Jones

In a previous report,6/ results were given that showed the amount of natural ventilation in a manhole having a capacity of 74.1 cubic feet when the number of ventilation openings in the cover was varied from no openings to a maximum of 48. The result s showed that the ventilation (air changes per day) in the manhole was proportional to the area of the openings in the cover, and also that the number or area of the openings was the factor that chiefly affected the ventilation.

Jan 1, 1937

By J. M. Pugliese

The Bureau of Mines, in support of its overall goal of helping to meet future U.S. demand for minerals, undertook this study to aid the quarry entrepreneur and/or operator in developing quarries near urban areas. In response to increased environmental concerns, the quarry operator often must take steps beyond those required in the last decade toward gaining permits for quarrying near metropolitan areas. Following the steps suggested in this report should increase the chances to obtain the permits to open and develop a quarry. Each task and question in the general plan flow diagrams are described in detail, with the flow diagrams aimed at the goal of acquiring the necessary permits. The appendixes include (1) types of projects for which Environmental Impact Statements (EIS's) may be prepared and Federal agencies responsible for preparing them, (2) State contacts for information regarding environmental impact assessment requirements and mining and mineral land reclamation laws, (3) a checklist of environmental inventory factors, (4) a tabulation of different regulations that affect mining in Michigan and the number of townships and counties that have each of the listed regulations, and (5) environmental logic associated with site selection. A central recommendation is that the quarry entrepreneur and/or operator coordinate plans at the beginning with local government officials (such as township supervisors and/or city and county planning board members), State and Federal officials, and public groups that will be affected.

Jan 1, 1979

By Clarence Karr

THE BUREAU OF MINES is investigating methods for upgrading tar produced by the low-temperature carbonization of bituminous coal. This survey was undertaken to compile information needed for identifying the ether constituents of low-temperature tar. Physical properties are listed for 1,024 aromatic ethers. The compounds include cyclic and noncyclic, polyfunctional and monofunctional ethers with oxygen joined directly to either one or two aromatic rings. Alkyl groups up through butyl are included. The compounds are divided into 37 groups ranging in complexity from alkoxybenzenes to dibenzopyrans. Compounds containing aromatic ether groups are important constituents of the neutral oxygen components of low-temperature tar. For example, at Morgantown, W. Va., the Bureau of Mines has identified and determined the amounts of benzofuran, 2-, 3-, 5-, 6-, and 7 -methylbenzofuran, diphenyl ether, dibenzofuran, 2,3-dimethyldibenzofuran, and two other dimethyl-dibenzofurans in the neutral oil from a low-temperature bituminous coal tar (103, 104).3

Jan 1, 1962

During the period January 1, 1977 through July 31, 1977, 5 percent (264,000 tons) of U.S. capacity was closed due to power curtailments in the Pacific Northwest because of the shortage of water. During July, one plant in Tennessee cut production by 50,000 tons annually due to a power reduction by the Tennessee Valley Authority. Full capacity production was resumed at a West Virginia smelter during September. If demand for aluminum is strong it seems likely that aluminum supply during the remainder of 1977 and in 1978 will be tight. The price was increased 3¢ per pound to 51¢ per pound effective March 28, 1977, and by an additional 2¢ per pound to 53¢ per pound, effective July 5, 1977. New projects and expansion of existing facilities are planned by Australian aluminum companies over the next 2 to 3 years. The companies listed have committed themselves to spending approximately A$801 million: Alcoa of Australia Ltd. -New alumina plant at Wagerup, south of Perth. Darling Ranges bauxite is located near the proposed project. A$650 million. Coma 1 co Industries Pty. Ltd. -Increase bauxite mining capacity and upgrade or replace other facilities at its Weipa mines on Cape York Peninsula region of Northern Queensland. A$81 million. Alcan Australia Ltd. -Expansion program that will increase capacity of the Kurri Kurri aluminum smelter north of Sydney about 50 percent, and improvement of other facilities at the plant. A$70 million.

Jan 1, 1977

By A. W. Hall

A nuclear method was developed for continuously and automatically deter-mining the moisture content of coal flowing through a bin. Fast neutrons from a 1 curie americium-beryllium source penetrate the coal, are thermalized (slowed down) by hydrogen in the moisture, and are counted by a thermal neutron detector. The difference between the number of these thermal neutrons and those thermalized by dry coal (in a reference drum) is a measure of the moisture content of the coal. A materials handling system was developed and in tests at a commercial coal preparation plant, moisture in coal was monitored continuously within 0.2 percent of values determined by conventional means. The meter responded rapidly to change in moisture content, making it adaptable to automatic process control, and was operated for 1 year without malfunction or recalibration. Shielding of the source by the coal kept the neutron flux level at the bin wall less than 1 milliroentgen per hour, a safe level for personnel.

Jan 1, 1973

By Louis A. Panek

Determining the change of stress in rock based on measurements of the deformation of a drill hole is a procedure that is increasing in popularity. A closely related procedure involves the applicat10n of this principle to determine the existing stresses in a rock medium, by cutting free (core drilling) an annulus containing the drill hole. In this Bureau of Mines report, expressions are derived from which one can calculate the stress ellipsoid--the three-dimensional change of stress, or the existing three-dimensional stress field, as the case may be. Study of these equations shows that the stress components in three dimensions can be determined by measurements in only two drill holes, and yields general principles that are useful in planning an efficient program of drilling and measurement. Procedures are given for calculating the least squares estimates of the stress components and their standard errors, and for evaluating or comparing calculated values by means of standard statistical inferences.

Jan 1, 1966

By Constantine C. Popoff

This report reviews and analyzes, by a simple analytical and logical reasoning, the conventional methods of reserve computations of mineral deposits described in various domestic and foreign publications. It brings together, formulates, and evaluates the principles underlying interpretation of exploration data; and ties such principles to the proposed classification of methods. The material is discussed in sufficient detail to allow general application.

Jan 1, 1966

By Terry J. Kreidler

In recent years, west-central Arizona and adjacent California have become the focus of geologic and exploration attention because of its excellent exposure of detachment-fault terrane. Detachment faults, normal faults with nearly horizontal fault planes, are the result of regional extension. Rocks on the lower plate consist of mylonitized intrusive, metasedimentary and crystalline rocks highly altered to chlorite; upper plate rocks comprise sedimentary, volcanic, metasedimentary, and metavolcanic rocks. The movement of the detachment fault causes the rocks on the upper plate to be severely fractured and brecciated thus making them Ideal conduits for mineralizing fluids. Mineralization favored the more reactive sedimentary and volcanic rocks of the upper plate. Three gold deposits, located in upper plate rocks, are currently being mined along the Colorado River corridor: the Picacho Mine near Yuma, Arizona, 70 mi south of the study area; the American Girl Mine In southeastern California, 60 mi southwest; and the Copperstone Mine near the southern end of this study area. Samples from the above three mines were used to create a geochemical model of detachment-related gold deposits. Antimony, arsenic, barium, copper, mercury, molybdenum, manganese, tungsten, and zinc all occur In the mine samples in concentrations at least three times greater than found elsewhere in similar rock types. Samples taken by the Bureau from the wilderness study areas contain similar anomalous concentrations of the same elements as well as elevated concentrations of several other elements Including: lead, fluorine, cerium, uranium, and samarium.

Jan 1, 1992

By P. G. Guest

Many of the gases and vapors used in anesthesia form explosive mixtures with oxygen or air. Sources of ignition for these mixtures always have existed, in operating and anesthetizing areas. When ether was first introduced, candles and gas-lights and coal stoves caused fires and mild explosions of the vapor-air mixtures. Today the chief causes of ignition are electrical. Fires and explosions are still much too frequent; and, because many of the mixtures are rich in oxygen, the explosions sometimes are very violent. Obvious sources of ignition, such as electric-power sparks and arcs in open motors, switches, and receptacles, as well as exposed incandescent wires and hot plates, usually are recognized by hospital personnel and corrected. A source of ignition that is not so obvious to many is static electricity. Until quite recently the presence of this hazard in a large majority of anesthetizing areas was not even suspected. However, numerous explosions -many of them fatal to patients -have been attributed, with good reason, to sparks from static electricity. In this paper the authors present facts to show the prevalence of static electricity in the average hospital anesthetizing area, and the degree to which this easily developed electrical form of energy constitutes an explosion hazard. An effort is made throughout to explain how static electricity behaves, why it is a hazard, and why certain safety measures are needed and recommended. Following the introduction and a short general discussion of static electricity, which incorporates a glossary of pertinent electrical terms, an account is given of inspections and tests made in a number of hospitals. This account includes many suggestions that should be useful to any person who plans to make similar inspections and tests. However, a comparison of materials and equipment used with those described in the report will reveal, in many cases, the potential dangers and obviate the necessity for tests. The hospital work was supplemented by considerable laboratory research designed to determine the spark energies required to ignite anesthetic-gas mixtures and the exact amount of time involved in developing the usual static charges. The results of this research are reported and the implications examined. The paper concludes with a general discussion of static and related hazards in anesthetizing areas and of the most urgent preventative measures.

Jan 1, 1952

By L. J. Kane

Conventional methods for determining the size of dust suspended in a gas require that agglomerates (clusters of particles) first be broken into particles, but in evaluating industrial dust-removing equipment the size of the agglomerates as they actually exist in the gas stream is far more important. This paper presents results of an investigation by the Federal Bureau of Mines to develop methods for determining the size of dust agglomerates suspended in a gas stream. The studies are part of the Bureau's continuing research on synthetic liquid fuels. The size and size-distribution of agglomerates as they exist when the gas reaches the filter was determined by using a membrane filter in conjunction with a dust count under a microscope. A membrane filter is a cellulosic sheet about 150 microns thick containing millions of holes per square centimeter--holes of uniform diameter that run directly through the sheet without interconnection.

Jan 1, 1960

By Thornton L. Neathery

Geologic investigation of a mineralized zone in eastern Alabama indicates that large quantities of talc and soapstone are scattered over a wide area close to the surface. Laboratory experiments show that this material may be upgraded to a high-quality talc. A market survey indicates that the talc deposits may be of current and long-range interest. The anthophyllite asbestos which is associated with the talc does not appear to occur in sufficient quantities to be considered as a primary commercial source.

Jan 1, 1967

By Raja V. Ramani

The potential usefulnuss of reclaimed surface-mined land has received much attention in recent times. This attention is partially due to the establishment of federal environmental reclamation standards but concern for achieving better land uses has also been shown by interested members of the mining industry. In an effort to develop a procedure for evaluating postmining land use potentials, specific mines in various regions of the U. S. were studied to determine the extent of current mined-land planning and to discover characteristics that are regional in nature. As part of this investigation, a 430-acre surface mine in Clear-field County, Pennsylvania has been studied. Established site planning principles have been applied to the case study site including formation of a data base, development of alternate land use plans, and evaluation of the economic, environmental, and social impacts of the land use alternatives. Key factors affecting site realization have been identified along with positive suggestions for applying land use planning processes to mined-land planning.

Jan 1, 1983

This report presents the results of reconnaissance-level investigations of the mill refuse disposal systems for 15 plants throw-heat the conterminous United States. The sites visited represent a cress section f the copper, iron, lead and zinc, and phosphate industries' practices in the field of fine-grained refuse disposal. The reconnaissance-level investigations were carried out to gather supplemental data to tae in-depth studies of Kennecott's Magma and Phelps Dodge's Morenci tailings deposits and Kennecott's Chino leaching dump. The various sites visited were classified according to the different systems and techniques used by the mining industry. The probable effects and relationships between site conditions and disposal methods were determined and evaluated to the extent feasible by a reconnaissance level investigation.

Jan 1, 1974

By Wilbert T. Malenka

A modified factorial experiment was used to determine the effect of operating factors in hydraulic mining of anthracite. Seven basic factors at various levels were considered. The significant factors were found to be pressure-volume, pattern, and jet traverse speed. Mining data were programed for computer, and a prediction equation was determined from printout information based on the hydraulic "jumbo" operating parameters and characteristics of anthracite, The source of error is discussed. The prediction equation is general in nature and might be useful in delineating performance characteristics in the design of equipment and/or more effective utilization in a medium with characteristics similar to those of anthracite.

Jan 1, 1968

By J. J. Shields

This study by the Federal Bureau of Mines concerns different methods of face haulage used with various types of continuous-mining machines, mobile-loading machines, and track-mounted equipment under varying roof and bottom conditions and in coalbeds of varying thicknesses. This report is the ninth in a series on mechanical mining in bituminous coal mines. Reference to the reports previously published is made in appendix III, p. 106. Use of modern mining equipment in bituminous coal mines has resulted in increased productivity at the face. This especially is true where continuous-mining machines are used, and the supervision is good. Previous methods and equipment for moving coal from the face became inadequate and had to be improved to restore balance to the mining systems. Sometimes new equipment was needed to improve the face haulage, and in some instances, a new combination of existing equipment was used. Detailed studies of face haulage methods were made at 13 mines in Pennsylvania, West Virginia, Ohio, and Illinois to compare their effectiveness and to describe fully the conditions under which each method was used.

Jan 1, 1960

By David J. Kusler

This study is an appraisal of the feasibility of recovery and the possible chemical and physical uses of the limestone from the Greenbrier Formation in western West Virginia. Data on minability, occurrence, quality, and markets were obtained from published and unpublished sources and by a limited mail survey combined with personal contacts. The estimated costs of recovery by deep mining techniques are considerably higher than competitive surface and shallow subsurface operations. Compositional in formation available for this study was limited but indicated the suitability of the limestone for most physical uses and some chemical process uses in appraisal of the uses and demand reveals that immediate markets may be difficult to establish, but for some uses long-term prospects may be encouraging, especially if the quality of limestone would be suitable for lime manufacture or use as metallurgical fluxstone.

Jan 1, 1968

By I. Liebman

The Bureau of Mines conducted research to develop triggered barrier systems for protection against gas explosions that can occur in underground coal mines during the use of continuous miners. Several extinguishing agents were tested in barriers at a simulated mine face. Water, powered by pressurized nitrogen, was found to be efficient in stopping fully developed gas explosions, but it had little effect against the explosion during its incipient stage. Hybrid combinations of currently known extinguishants, however, were successful against incipient explosions. Three hybrids that were developed and tested consisted of Halon 1301, combined with either an aqueous foam solution, water, or a dry chemical powder. The three hybrids were found to be more efficient than any constituent alone. Results of the tests point to a synergism between the hybrid components, and indicate that the Halon aids in dispersing its constituent and also converts the aqueous foam solution into a stable fine foam and the water into fine drops.

Jan 1, 1978

By A. J. Farstad

Recent advances in microcomputer technology have opened the way for systems which can track the location of underground mining personnel from the surface. A computerized system has been designed which is capable of not only tracking the location of the miner but also of monitoring underground parameters, communicating between work stations and sounding alarms when underground conditions are judged to be unsafe. For the system described herein, the locations of the underground personnel are detected by a network of underground terminals which routinely emit RF pulses to interrogate miniature transponders worn by the miners. Each transponder is uniquely programmed to delay its response in such a way that the RF terminal can identify the individual transponders by the time slots in which the responding pulses are received. The underground terminals are then interrogated by the host computer on the surface which keeps a running account on underground mine conditions and personnel. The underground portion of the system is designed to operate even during mine emergencies, deriving its power from rechargeable battery supplies which are float charged during normal operation. Nine mines were visited on this program and the industry reaction to the system was generally favorable. By slanting the system design for daily use in the mine, the chance of its acceptance by the industry is enhanced. Furthermore its likelihood of being operational in the event of an emergency is significantly increased.

Jan 1, 1981

By E. E. Ungar

Criteria applicable to noise in coal cleaning plants are presented, and the generally applicable noise control principles and approaches are discussed. The operating characteristics and equipment of coal cleaning plants are described. Considerations entering in the selection and design of noise control means are delineated, and specific means for equipment noise reduction are described. The limited utility of acoustically absorptive materials in plant spaces is indicated, administrative means for reducing worker noise exposure are pointed out, and ear-protective devices are described briefly. The reduction of plant noise reaching nearby communities is discussed. Programs leading to quieter machines an coal cleaning plants are suggested.

Jan 1, 1974