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By David F. Smith, F. A. Hartgen

"Incidental to a cooperative investigation with the Carnegie Institute of Technology and the International Combustion Engineering Corporation on the burning characteristics of a powdered coal and the powdered semi-coke therefrom, the U. S. Bureau of :alas has determined the relative temperatures at which rapid self-heating occurs in these two fuels. Determinations were made on various screen sizes of the two fuels. Chemical analyses on different sizes were made in the bureau's Coal Analysis Laboratory, of which H. M. Cooper is in charge. The true densities were determined b the method given in Bureau of Mines Technical Paper 8.4The apparatus used in the determination of the temperatures for rapid self-heating was similar to that used by Wheeler A 10-gram sample of the fuel was placed upon a screen in a glass tube enclosed in a vertical electric furnace. The tube was surrounded with sand. One thermocouple -as imbedded in the sand and another in the fuel. Measurements of the temperatures were obtained at regular intervals with a recording potentiometer, as the furnace temperature was uniformly raised. Dry air was passed down through the fuel samples at a uniform rate of 123 c. c. per minute; the temperature of the air was substantially that of the furnace."

Oct 1, 1929

By A. J. Miscoe, W. M. McKewan

A unique machine for inducing bending fatigue in wire ropes was built at the U.S. Bureau of Mimes' Pittsburgh Research Center. This machine can produce nine levels of degradation through repetitive cycling of long samples of wire ropes of the types used in the mining industry. This report provides an analysis of the results of the first wire rope to be fatigued on this machine. These results have indicated that as a wire rope accumulates bending cycles, its strength first decreases because of wear and then in- creases due to cold working of the wires. As the amount of cold working increases, more and more of the embrittled wires break and the strength of the rope decreases rapidly. In this test, application of several of the regulatory retirement criteria to various sections of the rope suggests that there may be some inconsistency among them.

Jan 1, 1993

By James V. Kelly

During the winter of 1946 and the spring of 1947, the Bureau of Mines conducted an investigation and drilling program in the vicinity of the village of Fairplay, Wis. Fifteen diamond drill holes totaling 2,457.6 feet of bore were completed. This work was part of a general study of the zinc-producing area of southwestern Wisconsin and had the particular purpose of investigating a structural trend, determined by the Federal Geological Survey, in an area some distance from known ore bodies or active mines.

Jan 1, 1948

By D. E. Fogelson

In a factorial experiment, blasting caps were detonated in three sizes of shotholes in mortar with three types of stemming--dry sand, wet sand, and hydrostone. Free-surface displacement pulses were recorded with a capacitive-displacement gage at a distance of 15 inches. The effects of decoupling and the type of stemming on the amplitude and the duration of the displacement pulse were determined. Both the amplitude and the duration of the displacement pulse were significantly decreased by increasing the decoupling, but they were little affected by the type of stemming.

Jan 1, 1965

By Richard H. Spencer, Warren G. Bender

Since the passage of the Coal Mine Health and Safety Act of 1969, the Bureau of Mines has made many advances in mine communications. These efforts have resulted in the following developments and demonstrations: • Surface-to-surface electromagnetic transmission of baseband voice signals through overburdens as deep as 600 feet. This transmission was achieved with equipment from the Interim Mine Rescue and Survival System Program, and demonstrated that baseband voice communications could be obtained through these overburdens in the absence of mine-generated noise; that is, when the mine power system was shut off. However, during mine operational conditions, the mine-generated noise proved to be so large that effective baseband voice communications to the desired depths could not be effected. • The development of beacon transmitters for locating trapped miners. This work was again the outgrowth of the Interim Mine Rescue and Survival System. Extensions of this work have led to reliable detection and location of trapped miners to depths of 1000 feet. The system, which makes use of a loop antenna deployed where the trapped miner is located, uses low-duty-cycle, tone-burst transmission. Portable tuned receivers and loop antennas are used on the surface to determine the location of the trapped miner. An extension of this work has led to a call-alert paging system concept, wherein a transmitter, similar to that used in the trapped miner system, is used to audibly and/or visually alert key mine personnel carrying pocket receivers that they are wanted at the nearest mine telephone. In addition, a roof-bolt paging system has been developed, wherein commercial paging and mine carrier phone equipment are used in conjunction with a long-wire "roof bolt" antenna to page individuals and relay to them short voice messages.

Jan 7, 1975

By Mark S. Stagg

Blast-induced ground vibrations from surface coal mine, quarry, and construction blasting were measured and analyzed for frequency content and duration characteristics. Eighteen commercially available ground vibration measurement systems were evaluated in the field and laboratory for linearity, accuracy, and crosstalk. Buried, surface, and sandbagged transducer placement methods were compared, along with peak and vector-sum measurements. The recommended minimum frequency ranges for ground vibration instrumentation are 2 to 150 Hz for coal mine and quarry blasting, and 5 to 200 Hz for construction and excavation blasting. When higher or lower frequency vibrations are possible, as in construction blasting or for a quarry shot close to a residence, care should be taken to insure proper choices of instrumentation and vibration criteria. Several instruments operating in these ranges are available, and all but one of the seismographs tested fell within ±3-dB accuracy limits (+41 pct, -29 pct). Waveform recordings of all three ground vibration components are recommended as the peak amplitude and frequency may vary among the three. Peak or vector-sum readings are adequate if only amplitude levels are desired. The soil density matched box should be anchored or buried, particularly for high-frequency, high-amplitude construction blasting.

Jan 1, 1980

By K. J. Liles

The Federal Bureau of Mines conducts a comprehensive test program on clay and shale at the Tuscaloosa Metallurgy Research Center. All samples are subjected to standard preliminary ceramic tests, which include firing formed briquets at temperatures ranging from 1,000° to 1,250° C to identify firing range and colors, and quick-firing to determine bloating characteristics. Materials that shop potential as structural products are further tested after either extrusion or dry-pressing. If the quick-fire test is positive, bulk samples can be fired in a rotary kiln to evaluate their potential as light- weight aggregate A number of miscellaneous tests also can be conducted if requested. These tests determine properties such as refractoriness (pyrometric cone equivalency), oil-bleaching characteristics, oil absorbency, viscosity for drilling-mud applications, sand-bonding properties for foundry usage, and pelletizing characteristics.

Jan 1, 1977

By Linneas Laage, Thomas Weber, William Pomroy

"Underground mine fires can significantly influence mine ventilation airstreams, in some cases throttling or even reversing airflows. As a result, the performance of a metal and nonmetal mine stench fire warning system, which depends on the ventilation to carry the vital warning signal, under fire conditions is different from performance under nonfire conditions. The safety of underground miners can be jeopardized if the warning signal is delayed. This Bureau of Mines report describes research to investigate fire and stench warning system interactions. A computer model is presented that permits quantitative analysis of stench warning signal delays as a function of fire location and intensity. The results of a case study involving computer simulations of stench distribution in a hypothetical mine network subject to various fire exposures are also discussed. This case study illustrates a technique for identifying the areas within a mine that are subject to unacceptable warning signal delays, thereby enabling preemptive action by mine personnel, such as redeployment of stench injectors. INTRODUCTIONFires are an ever-present threat to the safety of underground miners. Since the smoke and toxic gas produced by a mine fire can be spread rapidly by the mine's ventilation system, mine evacuation must be accomplished as quickly as possible in the event of fire. In metal and nonmetal mines, the most common means of passing the fire warning signal to each miner is the stench system. The typical stench system utilizes ethyl mercaptan, a highly odoriferous organic compound, injected on the surface into the compressed and/or ventilation airstreams. Upon smelling the stench, workers evacuate the mine according to an emergency preplan.Although the stench system has been used successfully for over 60 yr, it has several serious shortcomings, owing to certain chemical properties of ethyl mercaptan and to certain performance characteristics and limitations of present injection systems.Recent Bureau research succeeded in upgrading the overall safety and effectiveness of the stench system through the use of a superior stench odorant and the development of improved stench injection equipment (1).4 This research has also investigated a specialized computer simulation model capable of calculating the precise concentration of stench in any mine ventilation network branch at any time after stench release (2). An adaptation of the computer model now enables the analysis of stench system and ventilation system interactions under the influence of a mine fire."

Jan 1, 1987

By M. C. Irani

The Bureau of Mines, in cooperation with the Mine Safety Appliances Co., has developed a continuous-recording methanometer utilizing a catalytic combustion detector. The methanometer, which is presently operating at 22 exhaust fans at 14 mines in the Eastern coalfields, is reliable and simple to install, operate, and maintain. The instrument and the details of its installation and calibration are described. Analytical data obtained by infrared spectrophotometer and gas chromatograph are presented to substantiate its re liability.

Jan 1, 1974

By Owen W. Terry

During the summer of 1943 the Bureau of Mines conducted an investigation and program of churn drilling on the McIlhon and adjoining Pearson land in the Mineral Point district of Iowa County, Wis. Sixteen holes, aggregating 1,570 feet .of bore, were completed. The work was undertaken as part of a general investigation of the zinc-and lead-producing area of southwestern Wisconsin at a time when great effort was being made to increase the production of Metals important to the war program. The Bureau's drilling program supplemented a previous drilling pro-gram conducted by the Vinegar Hill Zinc Co., and demonstrated the presence of a strongly mineralized zone at relatively shallow depths.

Jan 1, 1948

By P. J. Colbassani

Samples of mine atmospheres collected by Federal coal-mine inspectors during their inspections and investigations of coal mines, in accordance with provisions of the Federal Coal Mine Safety Act (66 Stat. 692; 30 U. S. C., sees. 451-483) are analyzed routinely by chemical methods at Bureau of Mines laboratories. When samples collected in open workings of nongassy coal mines at points not less than 12 inches from the roof, face, or rib contain 0.25 percent or more methane, the act requires the operator, during operation of such mine, to comply with the provisions of sec. 209, Title II, of the act, which pertain to gassy mines. The methane con-tents of such samples are determined by a physical method based on infrared absorption spectrometry to provide an independent check on analytical results obtained by chemical methods. This information circular describes the equipment and procedures used by the Bureau for determining low concentrations of methane in coal mine atmospheres by infrared absorption spectrometry. ACKNOWLEDGMENTS The authors are indebted to Dr. R. A. Friedel, Chief of Spectrometric Section, Branch of Coal-to-Oil Research, Bureau of Mines, for suggesting the analytical method and for furnishing valuable advice and assistance, and to J. A. Queiser of his staff for making exploratory measurements by this method; to Dr. M. G. Zabetakis of the Division of Explosives Technology for his assistance during the conduct of preliminary experimentation; and to L. B. Berger, Chief, Branch of Health Research, under whose guidance the equipment was procured and the work conducted.

Jan 1, 1958

By J. G. Stuart, A. W. Cipkins, R. H. Thompson

Preliminary safe distances for blasting wiring from typical electromagnetic sources are presented. The distances are for underground coal mines and electromagnetic sources in the frequency range below 10 MHz. The distances are based on measurements performed at 3 locations in each of 3 coal mines. The measurement apparatus, measurement procedure, measurement results and the rationale used in the calculation of the safe distances are all described. The safe distances presented are dependent on the measurement results and their interpretation. More measurements are clearly necessary to establish the validity of the suggested distances.

Jan 1, 1985

By N. E. Hanna

An investigation was made of pressure pulses produced by unconfined explosive blasts in underground openings. Four tests were made with TNT or modified amatol charges ranging in weight from 60 to 2,000 pounds; each test involved either single or multiple charges. Pressure-time profiles were obtained using mechanical self-recording pressure gages. The cube-root scaling law for peak pressure was found to be valid within about 1 tunnel diameter; at greater distances, the pressures obtained along direct paths were generally higher than this scaling law would indicate.

Jan 1, 1968

By Sean Gallagher

The vast majority of ergonomics research has addressed the demands of work in standing or sitting postures, and understandably so. However, many workers (for example, underground miners, aircraft baggage handlers, plumbers, agricultural workers, mechanics, and others) are often required to adopt postures such as kneeling, stooping, squatting, or lying down for significant periods of the work day.

Jan 1, 2005

By Richard F. Hewlett

Engineers at the Bureau of Mines Denver Mining Research Center have been a research program investigating the theory and application of mine sampling. Part of this program is an investigation of the efficiency of sampling methods that involves development of sampling-method theory through simulating ore-deposit samples and assays, using - electronic digital computer. Theoretical developments are checked against actual ore-deposit sampling, assay, and production data by the commonly used polygonal and triangular methods of computing grade and tonnage of ore reserves. To speed the computing procedures, a program has been developed utilizing a medium-size digital computer for computing ore reserves by the polygonal method. This program calculates nine prismoids per minute at a total cost of $0.21 per prismoid. The complete program, written for an augmented IBM 650 computer, is described in detail; it can be used without change for computing ore reserves for a low-grade deposit. Modifications necessary to convert the program to compute ore reserves for virtually any other type of deposit or grouping of ore horizons also are given; however, the program is limited to using only vertical drill-hole data.

Jan 1, 1962

By T. Estelle Gardner

Heat-capacity measurements were made over the range 8° to 350° K on beryllium sulfate dihydrate and beryllium sulfate tetrahydrate using an adiabatic calorimeter. No anomalies were noted in the curve for either compound. Smooth values of heat capacity, entropy, enthalpy function, and free-energy function were calculated from the heat-capacity data at 10° K intervals and at 273.15° and 298.15° K. The entropy values calculated at 298.15° K were 39.01 ± 0.12 entropy units (eu) for the dihydrate and 55.68 ± 0.17 eu for the tetrahydrate.

Jan 1, 1967

This report is the 26th in a series summarizing Bureau of Mines research and technologic work on coal and related investigations and the 8th of these reports to be issued on a calendar-year basis.1 It reviews briefly work in progress during 1961, and it provides references to publications by Bureau personnel during 1961 and also to a few older papers that were not cited in prior reports of this series. Details about some of the researches mentioned may be obtained by referring to the publications cited in the footnotes or in the further list in the Bibliography; other phases of work are reported here for the first time and will be covered in more detail by later publications. The coal program of the Bureau of Mines extends over the wide range of applied and theoretical studies indicated by the table of contents of this report. Applied studies are conducted in connection with the development and evaluation of new mining techniques, and the effective processing and utilization of coal and coal products. Analyses of coal, technical advice, and other assistance to Federal agencies in connection with fuel and boiler-water problems, and health and safety activities are among the practical services handled by the Bureau, Fundamental research such as that on coal structure and on the properties of coal is conducted because it will, over a period of the, furnish an increasing general knowledge about coal; scientists and engineers may use this knowledge in solving problems in mining and utilization of

Jan 1, 1963

By G. R. Smith

Critical and strategic metals are often present in small quantities in low-grade domestic ores. When these ores are leached, the resulting solution usually contains the metals in very dilute quantities. Selective electrowinning from dilute electrolytes was investigated by the Bureau of Mines. A metal deposit containing 84 pct nickel was electrowon from the leach solution of a complex domestic ore bulk flotation concentrate originally containing approximately 2 wt-pct nickel. Key to achieving accelerated deposition rates, in the case of dilute solutions, is the rapid movement of the electrolyte through the electrowinning cell. Pure, synthetic nickel electrolytes were used to establish deposition parameters, and to optimize electrolyte velocity or mass transfer rates. Hydrodynamic and electrodeposition parameters for both the synthetic and leach electrolytes are presented and the experimental research described. Selective electrowinning appears to offer a viable alternative to physical separation methods to obtain separate metal "concentrates" from low-grade ores.

Jan 1, 1983

This report summarizes the results of several field tests conducted by Collins for the Bureau of Mines under contract S0122076 and contract H0232056. The field projects represent a part of Collins continuing effort on a broad study of coal mine communications. These experiments analyze the propagation characteristics of radio signals in a working coal mine environment. The intent of the program is to provide basic propagation loss characteristics by which we may evaluate various approaches to an integrated mine communications system. The goal of such a system is to satisfy both operational and emergency communications needs in the mine.

Jan 1, 1974

By Harry W. Campbell

A mineral survey conducted by the U.S. Bureau of Mines in 1983 identified no mineral resources in the Beaver Meadows, Blind Horse Creek, Chute Mountain, Deep Creek/Battle Creek, and North Fork of Sun River Wilderness Study Areas (WSA's). A prospect east of the Beaver Meadows WSA has low potential for lead resources. Sand, gravel, and limestone occurrences are numerous in the WSA's; however, similar or better quality materials outside the areas are abundant and more accessible to potential markets. Impure coal and titaniferous-magnetite occurrences are near the WSA's, but are not known to occur within these areas. In 1983, there were 7,025 acres leased for oil and gas within the five WSA's; no current mining claims were in or near any of the WSA's. Evidence of mining activity was found at only one prospect in the WSA's. It is inside the Deep Creek/Battle Creek WSA; no resources or resource potential were identified at this prospect.

Jan 1, 1984