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By Nabil A. Bibawy

An improved method for preparing gravimetric standard gas mixtures of helium-4 in nitrogen has been developed by the U.S. Bureau of Mines. A single-pan 12-kg analytical balance that has a sensitivity of 3 mg is used to prepare the mixture. The balance will accommodate a cylinder having a volume of approximately 4 L that weighs approximately 5 kg. The method has been improved to a precision of ±O.04 pct by performing four successive dilutions, by improved handling of gases in the manifold, and by using an improved analytical method to select high-purity gases.

Jan 1, 1990

By David A. Benjamin

In 1986, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied part of the 24,600-acre Orejana Canyon Wilderness Study Area (OR-001-078), in order to evaluate its identified mineral resources. The study area, located in Harney County, 76 mi northeast of Lakeview, OR, is underlain by Miocene basalt, rhyolite flows, tuffs, and tuffaceous sedimentary rocks. No mines, prospects, or claims were found within the study area. According to the U.S. Bureau of Land Management, the tuffaceous rocks have a moderate favorability for the occurrence of diatomite and a low favorability for zeolite resources. Also, the rhyolite flows have a low favorability for the occurrence of perlite resources. However, U.S. Bureau of Mines' studies indicate that no metallic or nonmetallic resources are present in the study area.

Jan 1, 1987

By H. F. Weaver

The 18th National First-Aid and Mine Rescue Contest was held in the Memorial Auditorium, Buffalo, New Vork, October 5, 6, and 7, 1959. The meet was sponsored by the Federal Bureau of Mines and the Joseph A. Holmes Safety Association, in cooperation with State mine inspection agencies, management and labor of the mineral extractive industries, and other safety minded groups. The Arrangements Committee, as authorized by the General Committee, made a11 the necessary arrangements for conducting the 1959 contest. Members of the Arrangements Committee were: Harry Gandy, Jr. (chairman), National Coal Association; James B. Benson, Southern Coal Producers' Association; Charles Ferguson, United Mine Workers of America; George C. Trevorrow, Bituminous Coal Operators' Association; and James Westfield, Federal Bureau of Mines.

Jan 1, 1960

By D. S. Kingery

Recent Federal coal-mine inspections have revealed some good and some definitely hazardous practices and systems for transporting; handling, and storing lubricants in and about coal mines. Improper storage or handling of. lubricants in coal mines has caused disastrous mine fires or, by supporting combustion, has made fires from other sources more difficult to fight. Careless handling of grease and oil around electrical equipment wastes much oil and permits entrance of grit and foreign substances into the working parts, which causes excessive wear and increases the possibility, of electrical ignition.

Jan 1, 1943

By E. D. Gradner

During 1924 a number of lives were lost and other men incapacitated by the toxic effects of gases produced in blasting in massive sulphides. In one mine, three men working in a raise were caught by gases from blasting a drift round in massive sulphide on the level. The round in the drift was shot ahead of time and it was necessary for the three men to travel through the gases to the intake air course. Two of the men lost their lives, and the third was injured, apparently for life. Other men at this same mine have been caught in the gases at blasting time and seriously injured. At a second mine, the gases from blasting in sulphides appear to be very dangerous, and it was necessary to send a number of men who were caught in such gases to the hospital. One man who was seriously gassed has not recovered in over a year is time. Another man similarly gassed soon died of influenza.

Jan 1, 1926

By S. H. Lorain

The Minah silver-lead mine in the Wickes district, Jefferson County, Mont., produced substantial quantities of silver-lead ores in the 1890's. The mine has been abandoned since the "silver panic" of the early 1900's. As a part of the Bureau of Mines: program to develop new sources of lead to overcome the growing shortages of that metal, a development project was started at the Minh mine in April 1946 and continued until June 1947, during which 5,600 feet of angledozer trenching and. 1,093 feet of core drilling were completed on the main vein and nearby parallel veins: As a result of this work, interest in the property was stimulated and private operators are now engaged in reopening the mine. This report discusses the past history, geologic setting, and the recent and early operations of the mine.

Jan 1, 1948

By G. W. Luxbacher

This volume describes the use of the Penn State Mine Ventilation Simulator (PSU/MVS) to model existing mine ventilation systems and, in addition, to evaluate the effect of system modifications. Ventilation survey methods designed to insure computer input data of sufficient accuracy for simulation purposes are covered in comprehensive detail, including quantity and pressure measurement and fan performance testing. The development of input data from ventilation survey results is discussed and illustrated by the use of an actual field survey. Two programs, written in FORTRAN IV with WATFIV, are presented to calculate airway head losses from altimeter pressure measurements. An existing coal mine ventilation system is analyzed and modifications to the system are simulated and evaluated. In addition the application of the PSU/MVS to non-coal mines is briefly discussed. An extensive bibliography on ventilation surveying and simulation is included.

Jan 1, 1977

By Maria I. De Rosa

The U.S. Bureau of Mines performed experiments to determine the hydrogen cyanide (HCN) concentrations and smoke particle characteristics during the combustion of flexible polyurethane foams and other nitrogen-containing materials, for the development of a test parameter. The experiments were conducted in an approximately 2O-L furnace at set furnace temperatures of 250° and 1,000° C for a 14-min duration, with an airflow through the furnace of 10 L/min. The variables studied as a function of time were the gaseous and aerosol HCN concentrations, the smoke particles average diameter (dg) and particle concentration (no), and the product of the smoke particle diameter and concentration (dgno). Carbon monoxide, carbon dioxide, and oxygen concentrations, sample mass weight loss, and furnace temperatures were also studied; analyses of nitrogen and cyanate content of the material were carried out. Results show that dgno correlates directly with the HCN concentrations, which depend on the nitrogen and cyanate contents of the material.

Jan 1, 2010

By A. J. Barry

Two methods of testing anchorages of headed expansion-type mine roof bolts were investigated by the Federal Bureau of Mines to determine whether they are acceptable for general use. In both methods a load was applied to a tightened bolt with a hydraulic jack. A total of 80 tests, 40 using each method, was conducted in 4 test areas in 3 commercial coal mines. Electric resistance strain gages were used in all tests to indicate true bolt load as the bolt was tightened and when an additional load was applied with the hydraulic jack. The results indicate that: 1. The relationship between the true bolt load and the jack load will vary according to the test method until the two loads become equal. The bolt load-jack load relationship below this point can be determined only with strain gages. 2. The point at which the two loads become equal can be estimated by noting the load when the hardened washer becomes loose in one method, and when the bearing plate becomes loose from the roof in the other. It also can be approximated for either method of testing by noting the load when the first abrupt change in the slope of the jack load-bolt displacement curve occurs. 3. The anchorage characteristics of the test bolt can be determined from the data obtained from either method by examining the slope of the jack load-bolt displacement curve above the point at which the true bolt load is equal to the jack load.

Jan 1, 1960

By W. D. Mcmillan

"Magnetic surveys made by the Missouri Bureau of Geology and Mines in 931 and 1932 disclosed a large positive anomaly about a mile south of Bourbon, Mo. 3/ Electrical resistivity measurements made by the Division of Geophysical Exploration of the Bureau of Mines in the winter of 1942-43 indicated that the source of this anomaly was in the pre-Cambrian rhyolite at a depth of more than 1,400 feet. 4/In order to determine the character of the material that caused the magnetic anomaly, which might be either a body of magnetite or a large intrusive of basic rock, the Bureau of Mines drilled four holes to depths of 1,800 to 2,300 feet. Magnetite in rhyolite porphyry was encountered at 1,600 to 2,000 feet, and this is doubtless the main source of the magnetic anomaly, although it is possible that additional iron ore exists at greater depth.Hole 1 was apparently located southeast of the source of the anomaly and encountered only small stringers of magnetite. Hole 2 penetrated four mineralized zones having a total thickness of 125.7 feet and an average weighted content of 43.52 percent iron and 31.62 percent silica. These zones were tested again by a deflection hole, 2A, which gave nearly identical indications. Hole 3, 500 feet north of hole 2, penetrated 58 foot of mineralized rhyolito containing an average 43.4 percent iron.Metallurgical tests showed that the silica in the ore is tightly locked with the magnetite. After grinding to minus 100 mesh, a 66 percent iron con¬centrate with 7 percent silica was obtained by flotation."

Oct 1, 1946

By P. M. Daling

The objectives of this study were to examine a representative cross section of formal safety analysis techniques developed for the nuclear and aerospace industries, to recommend those methods that would be suitable for application to the mining industry, and to include those methods in a user's manual. Volume II of this report, the user's manual, describes several methods that were determined to be immediately transferrable to the mining industry. The handbook gives detailed instructions on appropriate application and utilization of the methods. Other techniques will require further development before they can be effectively transferred to the mining industry.

Jan 1, 2006

By L. Cheng

This report describes a laboratory investigation of the effectiveness of low-pressure steam and a steam-water spray sequence for the collection of airborne respirable (<10 µm) coal dust. Comparison of present results to previous results obtained with water spray alone indicates that the use of steam in a steam-spray sequence increases the collection efficiency by about 14 percent over that obtained by water spray alone. However, the use of steam to collect airborne dust requires cooling the steam-dust mixture in order to achieve condensation of the steam, and steam does not appear to be an attractive approach for collecting airborne dust in underground coal mining operations.

Jan 1, 1974

By Oliver Bowles

The wire saw, introduced by the Bureau of Mines about two years ago, has revolutionized slate quarrying in Pennsylvania. The success of the saw since its early accomplishments has become greater and greater as the equipment has been perfected and skill acquired .in its use. In the first test made, a cutting rate of 9.7 square feet per hour was attained; in the next four cuts, made early in 1927, the average rate of cutting was increased to 12.8 square feet per hour; in 1928 a maximum of 34 square feet per hour had been attained, with a general average of about 20 to 25 square feet, The wire saw is now regarded as essential equipment in practically all of the quarries in the Bangor, Pen Argyl, and Windgap districts. The wire saw consists of a three-strand steel cable of 3/16 or 1/4 inch diameter running as an endless belt. The driving pulley is a 40-inch double-groove cast-iron sheave. A tension pulley supported by a frame mounted on wheels may travel back and forth on a short track. A weight of 800 to 2,000 pounds gives the desired tension on the wire. The driving units consist of electric motors with direct-drive compactly enclosed gear reduction, or double-belt speed-reduction units; the former is preferred. Silent chain and. pinion gear reductions are used to a limited extent. The travelling speed of the wire is about 15 feet per second. The driving and tension equipment are shown in Figure 1, A.

Jan 1, 1929

By W. Miola, R. V. Ramaoi

"The MSHA prescribed method for the determination of quartz in airborne respirable-dust samples from underground coal mines is the P-7 method, a combination of /ow-temperature, radio-frequency ashing (LTA) and infra7 red analysis (IR). There is no prescribed procedure for quartz analysis in bulk samples of coal and host rock. Dispersive infrared (IR), Fourier-transform infrared (FTIR) and X-ray diffraction (XRD) methods are most commonly used for the analysis of quartz in powders. Several aspects of the experimental procedures, such as the preparation of the analysis sample from bulk samples, ashing techniques, scanning procedures, peak measurement location, calibration techniques, sample amounts, size consist and data interpretation, affect the results from each of the methods differently. Significant differences in analytical results obtained from X-ray diffraction (XRD) and infrared spectroscopy (IR) on the same samples are reported. All studies point to the need for reliable quartz analysis methods.In a recent research program, a procedure for preparing bulk-coal and host-rock samples for quantitative quartz analysis was developed. Further, the results from X-ray diffractometry and infrared spectroscopy for quartz content on identical samples were compared. Calibrations with pure and mixed standards were used to assess the influence of particle-size distribution, matrix and calibration on the analytical results. In this paper, several issues concerning the measurement of quartz in the samples of coal, host-rock and airborne respirable dust from mines are outlined and quantified. IntroductionThe literature on coal-mine airborne-dust control has identified a need for a better understanding of the sources, mechanisms and amounts of quartz in mine airborne respirable dust (Althouse, 1984; Jankowski, Nesbit and Kissel, 1985; Ramani 1988; Qin, 1988; Bhaskar and Xu, 1990; Bhaskar and Li, 1992; Ramani, Qin and Miola, 1991 ). To understand the quartz content in the source materials, bulk samples of coal and host rock must be analyzed. Establishing an analysis procedure for determining the quartz content in bulk-coal and host-rock samples is necessary for identifying the sources of quartz in mines; for establishing the relationships between the quartz contained in the source and in the airborne dust; and for controlling the content of quartz in the mined product and in the airborne respirable dust."

Dec 1, 1996

By P. J. Coleman

Research in the field of mining safety and health in the United States plays an important part in protecting the lives of miners. The National Institute for Occupational Safety and Health (NIOSH) Mining Program conducts surveillance, studies and developmental work aimed at improving the safety and health of miners. With recent reviews of the Mining Program by the National Academy of Sciences and the Mining Program response (NIOSH, 2008), the importance of setting goals, conducting high quality engineering and scientific research and evaluating the outputs, outcomes, relevance and impacts of these projects has been reemphasized. Surveillance of reported injuries is a first step in deciding on research directions and in designing specific projects. Groups of injuries often share features and attributes that suggest common causes and may respond to similar preventive efforts. Identifying groups of injuries also serves to prioritize intervention efforts. The Mine Safety and Health Administration (MSHA) Accident and Injury database (MSHA, 2008) provides individual case reports of mining injuries, illnesses and certain no-injury accidents (events such as roof falls that stop mine production or miners? activities for more than one hour). This database is an indispensable resource for researchers and stakeholders needing information on the statistics of these events. From an epidemiological perspective, research projects target groups of miners at risk due to specific patterns of work, equipment, mine settings and the management of safety and health in their mines. Incidence rates are provided by the MSHA data for selected variables, such as surface/underground location, standard industrial classification and state. While incidence rates are the preferred measure for all variables, denominators are not typically available; for example, to more clearly under-stand the data about injury by occupational type, it would be necessary to conduct demographic surveys. A current survey of the demographics of the mining industry should be complete by 2010, which will allow incidence rates to be developed for a number of variables such as age, occupation and experience. This survey will provide the first update of its kind since the first survey was conducted in 1985.

Jan 1, 2010

By Stanley P. Jacobsen

Samples of fine coal refuse were obtained from 11 coal preparation plants throughout the United States. These samples were characterized by ash analysis, particle size, and mineral composition. From the characterization, geographical locations, and the dewatering equipment being used by the plants, five sites were selected for obtaining bulk fine refuse samples. The selected coal preparation plants were using for final dewatering thickeners followed by: a vacuum disc filter, a filter press, a belt press filter, a centrifuge, and a settling pond. None were using thermal drying. The moisture content of the final cake varied from approximately 23% to 50% depending upon the feed material, flocculant addition, and the type of equipment. The filter press gave the lowest moisture content followed by a belt press and then either a centrifuge or vacuum filter. The centrifuge products were all dried to an approximate 5% moisture in a thermal dryer.

Jan 1, 1981

By G. R. Palmer

Preliminary studies by the Bureau of Mines were conducted to determine the feasibility of a multiple-compartment, ion-exchange (MCIX) column simulator for examining the effect of multiple-orifice plates in the column. A rectangular, five-orifice, three-compartment, MCIX simulator with a cross-sectional plate area of 0.66 ft2 was used for the investigation. Orifices with open areas of 1, 3, and 5 percent were used with various operating conditions. The study was separated into three separate sections: (1) solution flow effect, (2) fluidization effect, and (3) resin transfer effect. The solution flow and fluidization studies showed that for solution flow rates of about 3 gpm/ft2, a I-percent open area plate functioned best, while at solution flow rates of 9 and 15 gpm/ft2, the best open areas were 3 and 5 percent, respectively.

Jan 1, 1981

By A. W. Frolli

This paper, describing the mining and reduction methods and costs at the Oceanic quicksilver mine, is one of a series of similar reports being prepared by the Bureau of Mines on various mines in the United states. The property, which is owned and operated by the Anglo American Mining Corporation, Ltd., is 5 miles east of Cambria, San Luis Obispo County, Calif. It lies in a region of steep hills and sharply incised canyons on the west slope of the Santa Lucia Range at an elevation of about 500 feet above sea level. The climate is ideal for living and operating conditions. A 40-mile paved highway connects the mine with San Luis Obispo, the nearest convenient railroad town.

Jan 1, 1937

By R. J. Heemstra

A method was developed for calibrating photographic emulsions and retrieving working curves for emission spectrography. The values obtained from a digital readout or a recorder chart of a comparator-microphotometer are converted to light intensity values using an emulsion characteristic curve derived from a quartic polynomial preliminary curve. The characteristic curve, consisting of Seidel transform versus the logarithm of intensity, is split into two cubic polynomials at the zero value of the transform, resulting in eight emulsion calibration coefficients. These methods allow use of the calibration curves even at very small and very high intensities, thus extending the range of analysis. Use of a small computer allows rapid calculations. A computer program was written to formulate, code, and file each working curve along with its statistical error. Proper coding of the input data permits the direct printout of the concentration of the elements under investigation.

Jan 1, 1970

By David C. Minton

This paper describes in detail the cost of equipping and developing the Golden Belt mine, Yavapai County, Ariz. These costs should be typical of the average small gold mine in central Arizona which has been equipped with used machinery a, a minimum of capital expenditure. The conditions of remoteness, transportation, water, and power supply are about average for properties in the Bradshaw fountains and that vicinity. There are several mines in the district in the process of development and several dormant properties that might be opened in the future. The Golden Belt group of claims was taken over by the present management in May, 1931. Although some active development has been carried on in recent years, resumption of work at the old property required entire rehabilitation of the equipment and camp. As the water level had not been reached, there was no problem of dewatering. In the presentation of costs in this paper an evaluation of the cost of equipment and development work as taken over by the Golden Belt Mines, Inc., has been made. Enact data, however, on previous exploration and construction costs are lacking. The total cost of equipping and developing the mine to its present stage has been obtained by adding the disbursements of the present management to the above-mentioned evaluation. These costs do not include the cost of replacing camp, equipment destroyed by fires, of unsuccessful milling experiments, management, or obsolete equipment on the property.

Jan 1, 1933