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By Howard J. Pincus

The purpose of the study is to investigate the effects of fracture filling and associated alteration on the mechanical behavior of rocks. Results are presented for specimens from the Climax and Henderson mines in Colorado and the San Manuel mine in Arizona. The rock types studied from each location are from 1) Climax, medium-grained - granite, fine-grained granite, granite porphyry, schist, and gneiss; 2. Henderson, rhyolite porphyry; 3. San Manuel, quartz monzonite and quartz monzonite porphyry. A description of the rocks was made including: color, texture, mineral composition, composition and fabric of fracture fillings, density and porosity. Unconfined and triaxial compression tests were run on the Climax and San Manuel specimens. Sonic relocities were measured during the compression tests; Shore sceleroscope hardness was measured before the compression tests. Tentative conclusions are that some relation appears to exist between compressive strength and the following properties and features for all the specimens: dynamic Young's modulus, sonic velocity, density, rock composition, and composition and fabric of fracture fillings - veinlets. There appears to be some relation between compressive strength and Shore scleroscope hardness and porosity for quartz monzonite (San Manuel). A relation appears to exist between compressive strength and texture for schist and between com¬pressive strength and extent of failure on fracture fillings for fine-grained granite, schist, and gneiss (Climax). We plan to perform additional analyses of data collected so far and data yet to be collected in the next few months, with emphasis placed on devising a practical index of alter¬ation that can be used in the field. Limitations on interpretations arise from such factors as heterogeneity of the rocks studied, the small range of confining pressures used, and other factors presented in the text.

Jan 1, 1973

By Gergely Markos

Uranium mill tailings represent a potential threat to the human habitat by containing large amounts of radioactive and chemically toxic substances in high concentrations. These: undesired components enter the human habitat in various pathways such as by erosion and water or air transport. The main objective of this investigation was to evaluate the actual movement and model the potential movement of contaminants by seepage of water from the tailings into the subtailings soil. This report represents various models of the movement of contaminants using both theoretical approaches and empirical evaluation of data available from other investigations. The data consist of field measurements and laboratory determi¬nations of major and trace cations, the dominant anions, pH, and Eh of moist solids, extracts, and waters from the tailings and surroundings. Evaluation and interpre¬tation of data were accomplished by using Eh-pH diagrams, various statistical methods and the WATEQFC computer program. Data analyses show that the critical area of investigating movement- is the interfaces between tailings and the external environment. The chemical differences at interfaces seem to result in a sink system for contaminants. The tailings-soil¬-water system shows extreme complexities because of chemical and physical hetero¬geneity of the system preventing the use of a single comprehensive model to represent real conditions. The validity of the simplifying assumption used has been shown and increasing complexity has been built into the models. Analogs of these models can be used for evaluation of similar systems.

Jan 1, 1981

By William H. Pomroy

Spontaneous combustion fires involving high-sulfide-content ores are a relatively infrequent yet serious safety hazard in mining. They are also the cause of lengthy mine shutdowns because they typically occur in areas of a mine where abundant fuel material is present but which are inaccessible for fire fighting. This Bureau of Mines report describes research to design, fabricate, and test in the laboratory and field a system that warns of spontaneous combustion fires in metal mines. Overall performance of the detection system was found to be satisfactory, in that the system was capable of reliably detecting low levels of combustion products believed to indicate the preflaming stage of spontaneous combustion in metal mines. Installation of similar systems in mines with a high risk of spontaneous combustion is recommended. Principal operating problems and recommended corrective actions are also discussed.

Jan 1, 1987

By Manuel Gomez, V. F. Parry, John B. Goodman

"INTRODUCTION The need for an accurate and precise analytical method for determining moisture in coals of high water content has been recognized by the coal industry as well as the fuel technologist. Interest in this particular phase of coal technology extends back to the early work of German investigators on the brown coals of Central Europe. Studies by these workers led to the establishment of a direct immiscible liquid-distillation method 4/ as the accepted moisture determining technique in European laboratories. Direct moisture determining methods, those methods that utilize various techniques to drive off the water from a given sample of coal and either collect the water in a calibrated receiver or selectively trap the water driven off in a suitable absorber, have found little favor in the United States. They have been treated merely as research tools.5/ The problem of moisture determination in low-rank coals of the United States has not been given much consideration because such coals contribute only about 2 percent of the total United States production. With renewed activity in low-temperature carbonization and with the growth of interest in coal and coal-tar hydrogenation, the American coals of lover rank containing 20 to 40 percent bed moisture will be subjected to extensive investigation. If the low-rank coals of the United States are to be accurately appraised, the need for qualitative and quantitative analytical proceeded becomes more pronounced. These coals, especially the lignites of Texas and North Dakota, are highly susceptible to oxidation, a process that proceeds to a greater or less extort when low-rank, high-moisture coals are treated by oven-drying methods. The extent of this atmospheric oxidation has been described and evaluated by numerous workers. 7/In many respects, the problem of moisture determination in low-rank coals, those found in the United States and the high-moisture coals of Central Europe, is similar. Conversely, the problem of moisture determination assumes a different aspect when the coals of the eastern and the middle-west sections of the United States are considered. Present methods, the loss in weight gravimetic-type procedures, serve adequately to test these low-moisture coals. The determination of moisture in coals containing 20 to 40 percent water should be approached from a direct method rather than from an indirect gravimetic-type procedure because of the oxidative tendencies of these coals and the demonstratrated inability of a loss-in-weight technique to remove all the water in a given sample of coal."

May 1, 1953

By J. P. Barkley

"The accompanying tabulation gives the results of a series of operating tests on two types of small stokers. One was an inclined, natural-draft, moving-grate, overfeed ""hand-stoker"" fired and manipulated by hand; the other was. a horizontal, forced-draft, stationary-grate, underfeed, mechanical unit-stoker operated by an electric motor. These were installed as shown by the accompanying sketches (figs. 1 and 2) under horizontal return tubular boilers of a nominal rating of 150 bl.h.p. each.The steam load carried by these boilers was a rather typical heating load. It was fairly constant and of about 30 bl.h.p. throughout the summer months, with small variation between day and night. During the winter months the daily variations were dependent upon the outside temperature. The boilers were banked a considerable part of the night.As noted in the table, two kinds of coal were used. The size of one kind was run-of-mine and the other 11/4 inch nut and clack. These coals from two different mines of the New River district both caked considerably during burning, the nut and slack more than the other. Analyses of the coal were as follows:"

Jun 1, 1929

By Joseph J. Wallace

The 1952 Annual Report of the West Virginia Department of Mines lists seven beds that are being mined in Mingo County, of which the Cedar Grove is the most important. The Cedar Grove, Alma, and Coalburg contain the largest remaining known reserves. 2. Known measured and indicated reserves in all beds, based on a minimum thickness of 14 inches and 1,800 tons per acre-foot of coal in place, are estimated at 3,007 million short tons as of January 1, 1953. Of this total, 2,396 million short tons is in beds 28 inches and more thick. Areas in each bed were omitted from the estimate because available data relative to the bed characteristics are too meager for making an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves.

Jan 1, 1954

By D. C. Dahlin

The U.S. Bureau of Mines investigated the magnetic susceptibility of minerals as a function of mag-netic field strength to determine how it might affect the potential for high-field magnetic separation as an alternative to other separation technologies. Single-mineral concentrates were prepared from specimens from the same deposit to compare magnetic susceptibilities of minerals that occur together and from specimens from different deposits to compare magnetic susceptibilities of like minerals. A vibrating-sample magnetometer with a superconducting magnet capable of producing a magnetic field of 7.16 x 106 Aim (90 kOe) was used to measure the magnetic moment of the samples. The data were then converted to specific magnetic susceptibility data and plotted as a function of magnetic field strength. Cursory studies were also completed on the effects of iron content and oxidation roasts on magnetic susceptibility in high fields. The results showed that magnetic susceptibility is essentially constant in magnetic fields above those needed to saturate ferromagnetic constituents. Although magnetic susceptibility is influenced by iron content and by thermal treatment, the changes are not large enough to influence separations in fields above 1.59 x 106 Aim (20 kOe).

Jan 1, 2010

By J. M. Kuchta

Experimental data are presented on the autoignition temperature (AIT) characteristics of the hydrocarbon jet fuel, JP-6, in various oxygen-nitrogen atmospheres under conditions of constant volume and constant pressure. AIT's of this fuel in air varied little with fuel injection pressure but increased greatly with decreasing fuel content at low fuel-air-ratios. They also increased with decreasing oxygen content of the fuel vapor-oxidant atmosphere. Consistent with thermal ignition theory, the ignition temperatures increased with decreasing initial pressure, ignition delay, and vessel radius; expressions are given which define the observed variation of AIT with these variables for JP-6 fuel vapor-air mixtures. The significance of autoignition temperature data obtained using various ignition criteria is discussed to show the usefulness of such data in evaluating fire and explosion hazards. In addition, data are presented on the extent of oxidation that occurs prior to autoignition of this fuel in air at various temperatures.

Jan 1, 1965

By W. K. Sawyer

Resistivity, porosity, permeability, and saturation data were obtained on core samples from the Big Injun, Clinton, Gordon, Bradford Second and Third, and Venango Second oil sands and formation factor-porosity relationships were derived using the general form of Archie's equation F = aø-m, where F is the formation factor, ø is the porosity, and a and m are constants that depend on characteristics of the rock. It was found that a and m varied significantly between sands, as did the exponent in the Archie relation I = Sw-n, where I is the resistivity index and S, is the water saturation. The average exponent, n, determined from all data was 50 percent greater at residual oil saturation than at residual water saturation. Samples from each sand exhibited differences in directional resistivity and/or permeability. The Bradford Third sand data showed correlation between resistivity and permeability anisotropy.

Jan 1, 1971

By Lewis M. McNay

The Bureau of Mines located and examined 292 burning coal refuse banks throughout the Nation's coal-producing regions in 1968. These coal waste fires, extending over 3,200 acres, produce poisonous, acrid gases and particulate matter that pose a threat to health and safety in the surrounding areas, damage vegetation, and cause the deterioration of nearby structures and buildings. Methods of extinguishing coal refuse fires are discussed, and an approach to eliminating future occurrences of these fires is presented.

Jan 1, 1971

By J. R. Thoenen, B. H. Clemmons, A. H. Reed

"INTRODUCTION AND SUMMARYOverall red-ore reserves in the Birmingham, Ala., area were estimated in 1910 by E. F. Burchard 4/. Since then mining has progressed into areas classed by Burchard as ""unavailable for exploitation"" under conditions existing at that time. This is understandable when it is considered that red iron ore was valued at $1.19 a gross ton at the mine in Birmingham in 19102/ and by 1948 had risen 300 percent; 6/ that skips had replaced cars in slope haulage; that mechanical loading and rubber-tired haulage had replaced hand loading and mule or locomotive haulage; and that other more efficient mining methods had been introduced. Intensive study during the intervening 40 years has been given to ways and means for upgrading the low-grade ores in the area and combining or blending them with raw red and brown ores for improved blast-furnace feed.It is reasonable to expect that future progress in mining efficiency and increased knowledge of the beneficiation characteristics of marginal ores will permit extraction of red-iron minerals now considered uneconomic.The Bureau of Mines has undertaken to restudy iron-ore reserves of the Birmingham area to determine what tonnage and grades of mineral are present; what is necessary to make them amenable to mining; what further advancement is possible in beneficia¬tion methods; and where increased production may be obtained in the area if and when required. This study has been underway for the past 2 years, but research into the beneficiation of marginal ores has been in progress at the Southern Experiment Station for the past 30 years. Many results of that research have been adopted in commercial practice in the area. Other results have not been published but are pre¬sented here in condensed form as an important factor in assessing marginal deposits with respect to their importance as ore reserves.An interim discussion of the salient features of past history and progress, as well as the data developed during the years of research in beneficiation at this station and the present field investigation, will make for a better understanding of the present position as well as be useful in evaluating future potentialities. Discussion in this paper is confined to the main Birmingham Basin area, which contains the largest concentration of hematite ores in the district."

Jul 1, 1953

By Rethel L. Hubbard

Fourteen straight-run asphalts were prepared in the laboratory from bitumens obtained from three sources: (1) native bitumen from Rozel Point, Utah, (2). bitumen extracted from Athabaska bituminous sandstone at Canada, and (3) bitumen extracted from Edna bituminous sandstone outcropping in San Luis Obispo County, to seven asphalts with penetrations ranging from 19 to 287 at 77 F. were prepared from each of the bitumens. The yields of the prepared asphalts ranged from 74.5 percent for a 27-penetration asphalt from the Athabaska bitumen to 99.5 percent for a 271-penetration asphalt from the Rozel Point bitumen.

Jan 1, 1949

By Joel N. Van Sant

The rapidly expanding economy of the West, with its growth of heavy industry, and increased steel production, is primarily responsible for the refractory clay industry's concern over the adequacy of the clay supply in States of the Great Plains and Rocky Mountains. Hence, the investigation by the Federal Bureau of Mines of the occurrence and use of refractory clays in North Dakota, South Dakota, Nebraska, Wyoming, Colorado, Utah, New Mexico, and Arizona has been encouraged by the major consumers and producers of this commodity. The Wyoming investigation is a part of the national program devised to close gaps in the domestic supply of specific types of clays to determine their characteristics and properties and to provide information that will assist the refractory-clay industry. Forty-two locations of clay-bearing rock in 17 areas in Wyoming were examined (fig. 1). Location 3 was not examined during this survey. Its description was taken from an earlier report. Locations 20, 21, and 22 were previously reported but were, also, examined by the Bureau. No samples were collected from these locations because field examination indicated that the shales were not refractory grade. The Hulett, Aladdin, and Newcastle areas are discussed in the section on the Black Hills district; the other 14 areas are described separately.

Jan 1, 1961

By T. C. Davis

Nine organic derivatives of fluorine, silicon, boron, and aluminum were purified for thermodynamic studies using distillation, zone melting, and gas liquid chromatography, The unusual properties of these compounds required the development of special techniques for handling and purification. To determine purities of purified samples, new techniques for analyzing spectral data were developed.

Jan 1, 1965

By Daniel T. Rogers

The Bureau of Mines, in its alumina miniplant project to investigate alumina recovery from domestic, non bauxitic ores, has conducted research on the use of a hydrochloric acid leaching, gas sparging crystallization technology. An important element of this research is the efficient separation of undissolved, siliceous residue from AICI3 -bearing leach liquors by continuous, horizontal, countercurrent vacuum belt filtration. In an effort to calculate material balances quickly and to predict material balances based on different belt filtration configurations, the perfect-mixing-cells-in-series model (PMCS) for calculating material balances around belt filters was used. Because of the porous nature of the solids, the model produced erroneous material balances. Therefore a reliable model, the shrinking voids model, was developed postulating the presence of an unwashable voids liquor volume that decreases with decreasing liquor AICI3 concentration. This volume decrease postulation is equivalent to assuming that dilute liquors flow more freely, causing more voids liquor volume to become washable. Least-squares based computer programs are provided, which are useful not only in producing material balances from plant data but also in predicting balances for untested configurations using the same feed materials.

Jan 1, 1982

By Charles E. Green

This study was conducted to identify, evaluate, and develop procedures to minimize or eliminate safety hazards associated with the electrokinetic dewatering process, such as toxic and volatile gas emissions, electrical shock, accidental detonation of explosives, electrochemical corrosion of metal appurtenances, and possibly others. The identification, evaluation, and procedure development were based on pertinent literature, existing safety regulations, interviews with mine personnel, physical and mechanical properties of the electrokinetic dewatering process, and physical characteristics of the material to be dewatered. The electrokinetic dewatering process was described in detail. Potential safety hazards were identified and evaluated. Procedures and/or safety regulations were developed to minimize or eliminate the potential hazards. It was recommended that the electrokinetic dewatering process when used in deep metal mines be properly monitored to obtain additional information on other potential hazards that possibly exist.

Jan 1, 1979

By G. St. J. Perrott, G. W. Jones

"In cooperation with The Edison Electric Illuminating Co. of Boston, Mass., a survey was conducted in 1929 and 1930 by the United States Bureau of Mines to determine the general hazards of combustible gases and vapors in manholes and other underground openings owned by this company. The territory served approximates 650 square miles and includes 46 cities and towns. The transmission and distribution systems are on overhead construction and underground wires and cables run in underground conduits and manholes. There are 17,000 manholes on the system, and also an area in Boston proper served by the Edison tube system. These conduits and manholes are laid in various types of streets from the most modern type of cement roadbed to the older type of loose macadam. The conditions as found could be considered as typical of any public utility in the electric-light and power field. The survey extended over a period of about a year beginning in June, 1929, and ending in July, 1930, and during this time 1,765 different manholes were tested and a total of 4,068 tests were made.Previous to starting the actual survey, one of the writers, G. W. Jones, spent considerable time in Boston determining the best methods of practical· test procedure. In this work cooperation was given by John Campbell, superintendent, special service department, who for a number of years has been making a study of explosions in underground street areas and preventive measures in Boston and various cities.After this preliminary investigation the tests were continued by employees of the Edisun Company. Copies of all records of tests were forwarded to the United States Bureau of Mines Pittsburgh Experiment Station so that the writers were in close touch with the progress of the survey, and changes could be made in the test procedure whenever deemed necessary."

May 1, 1931

By Robert L. Lagace

The purpose of the work reported herein was to investigate whether available telephone multiplexing equipment offered a means to rapidly upgrade the traffic-handling capacity of present mine telephone systems and provide for selective calling for safer and more efficient mine operation. Common sense was used to decide whether or not an item could be termed "available." Since conventional telephone gear is not designed to interface pager phones for example, existing shelf items would require adapters to compatibly interface these two types of gear for independent operation over the present single twisted pair used in mines. These and similar small items were allowed, but if a system required any extensive design work to adapt it for the mines, we ruled it "not available."

Jan 1, 1975

By O. E. Traubert, E. G. Meiter

"The daily sulphur dioxide content of the air at the Pittsburgh Experiment Station of the Bureau of Mines was determined by the bureau at the request of Committee D-14 on Screen Wire Cloth of the American Society for Testing Materials. The purpose of the investigation was to obtain data for use in interpreting screen-corrosion tests, which were conducted simultaneously and jointly by the committee4 and the Bureau of Mines.The plan of this investigation was to vale a single daily determination, except on Sundays and holidays, of the SO2 content of the atmosphere at the exposed test screens, for a period of one year. No attempt was made to determine the variation during the day, except on the morning of October 15, 1927, when the atmosphere was unusually foggy and smoky. Several successive determinations were made on that date to ascertain changes in the SO2 as the morning haze disappeared. The SO2 determinations were begun on August 11, 1927, and continued until August 11, 1923.The Pittsburgh Experiment Station of the Bureau of Mines is in a residential section about 3 miles east of the central or main business district of Pittsburgh. The air samples were taken on the roof above the auditorium, or the center rear of the building. This was also the place where the pieces of screen were placed for corrosion tests. The height was about 40 feet above ground level. Several sources of considerable smoke and SO2 are in the immediate vicinity. On the west side of the building is a double-track railroad. At this point the line runs through a cat below the level of the building. The horizontal distance between the air-sampling position and the railroad tracks is about 400 feet, and the vertical distance about 70 feet. The power plant for the Bureau of Mines building is about 250 feet south of the sampling position. About 1000 feet farther to the south are the engineering building and power plant of Carnegie Institute of Technology, and 1/4 mile to the southwest is the power and heating plant for the Carnegie Library and Museum. About 1 to 2 miles farther south and also southwest"

Jun 1, 1930

By A. J. Barry

A practical method has been developed and field tested which provides an estimate of the bearing capacity of mine roof and floor. The relationship between penetration of the strata and imposed loads is determined by in situ tests. Information of this type is needed to determine the maximum allowable pressure that may be applied by self-advancing supports on roof and floor of a longwall face without causing a punching type of failure.

Jan 1, 1970