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By R. R. Sayars

"Carbon monoxide is a gas slightly lighter than air, with which it diffuses readily to make a homogeneous mixture. It will burn and has a wide explosive range, that is, an explosion is possible when the air contains from 15 to 73 per cent of the gas3. This explosive range is about the same as that for hydrogen and over nine times As Tide as that for marsh gas (methane). Like air, it has neither color nor taste and has no odor in concentrations usually encountered, therefore it cannot be detected by the ordinary senses with which men are endowed. It is produced by burning carbon containing fuels, no coal, wood, gasoline, etc., whenever not enough air or oxygen is supplied to burn and oxidize the fuel completely.The human race has probably been exposed to this gas since men first began using fires in confined or sheltered places. The poisoning as usually encountered is an acute condition resulting from breathing atmospheres con¬taining this gas. A number of eases described in the ancient literature Indicate that carbon monoxide was a frequent cause of death by accident, suicide and is a means of punishment or torture. A quotation by Lewin from Aristotle who lived in 384-322 B.C., states that ""animals collapse from harmful odors as men gets a severe headache and often dies through charcoal vapors"". The Roman knew that smoke was poisonous, and used the greenest most smoke-producing wood to put persons to death. The occurrence of carbon monoxide increased in frequency through the years until at the present time it is found in the home as well as in many industries. The following table gives the approximate percentage of carbon monoxide found in gases from various sources of poisoning.4"

Apr 1, 1924

By Robert A. Jankowski

The Bureau of Mines has recently identified five major factors that contribute to high respirable dust levels on the six U.S. longwall faces having the most difficulty complying with Federal dust standards: (1) a poorly structured cutting sequence, (2) a poorly designed external water spray system, (3) marginal waterflow to the cutting drums, (4) minimal controls at the stage loader and crusher, and (5) the lack of effective controls for dust generated during support advance. The results of this survey illustrate the need to address all the major sources of longwall dust generation and the need for mine operators to implement a variety of control procedures to assure compliance. The Bureau of Mines will continue to assist mine operators in implementing improved dust controls and will work to identify and evaluate controls for dust generated during support advance.

Jan 1, 1983

By James C. Cawley

The Bureau of Mines has empirically determined ignition probability versus current for resistive circuits in an 8.3% methane-air atmosphere. Simple ignition probability, defined as the number of ignitions divided by the total number of sparks, was determined, and the corresponding currents were recorded. The experiment was designed to minimize the probability of not observing an ignition that should occur during a series of tests. For resistive circuits in 8.3% methane-air mixtures, the experimental results indicate that ignition was not achieved below 2,000 rnA at 20 V dc, 350 rnA at 30 V dc, 150 rnA at 40 V dc, and 175 rnA at 50 V dc. The simple probability of ignition corresponding to these currents is esti-mated to be, respectively, 1.0 x 10-6, 1.7 x 10-7, 3.0 x 10-7, and 1.0 x 10-5 The ignition mechanism seems to break down below this point, implying that a threshold current value exists below which spark ignition does not occur.

Jan 1, 1987

By Bruce D. Sartwell

A program was written which utilizes a remote teletype input to a time- sharing computer to plot charged particle or X-ray energy spectra which are stored in the memory of multichannel analyzers. The program, written in FORTRAN V, accepts the data printed out by the pulse height analyzer on paper tape and then, after reading these data tapes into the computer, plots on the teletype the desired energy spectra on a scale automatically adjusted for the maximum number occurring in the data. The program is flexible enough so that the researcher can subsequently expand or contract the vertical (intensity) or horizontal (energy) scales. With a slight modification, the program will accept data printouts from scalers or analog to digital converters. The program also includes a feature for integrating the energy peaks obtained by pulse height analysis.

Jan 1, 1970

By Byron M. Bird

"The prevailing practice of washing unsized coal, 1/2-inch and finer, to 1/8-inch and finer, on a table is subject to certain limitations which are commonly overlooked. In some instances good results are obtained by this method, but often the opposite is true and the efficiency of the washing operation is low. Although the separation taking place on a concentrating table is not fully understood, the actual distribution of particles of various sizes and specific gravities was determined a number of years ago by ore-dressing investigators. Hence this paper consists of an analysis of an old problem by new methods. The experimental data on which the discussion is based were obtained in the course of coal-washing investigations conducted by the U. S. Bureau of Mines at the Northwest Experiment Station in cooperation with the University of Washington and with certain coal operator: of that State.Experimental WorkThe general method of study has been to take a large number of zonal products from the table, and separate them according to specific gravity and size into their component parts. The table used is one of the standard commercial sizes with a diagonal deck. The coal to be washed is split into representative portions, which are stored in separate bins. One portion is used for ""timing as"" the table; the products are collected continuously in the same turned to the feed bin, and thus a closed circuit is completed. When the despite conditions on the table are obtained, coal is fed from one of the re. After the table is operating smoothly the entire product is minute; such a sample is sufficiently large to represent accurately the work of the table and at the same time to minimize the effect of beginning at the end next to the head motion, separate samples are made for each foot along the edge of the deck."

Jun 1, 1926

By S. M. Molloy

The postwar demand for insulating material such as mineral wool, in-creased in proportion to the rapid construction of new buildings, placing an enormous burden on the existing mineral-wool industry both in known sources of raw materials and in available plant facilities. In view of the increased demand on the industry, the Bureau of Mines in its Mississippi Valley Experiment Station" Rolla, Mo., undertook an investigation to aid the industry by establishing resources of raw materials through actual laboratory wool-blowing tests and by developing certain methods for evaluating the physical proper-ties of a mineral wool. As material was received from the public, laboratory-evaluation technique had to be developed, the results of which would reflect in the mineral-wool-industry standards. The methods of testing used by the mineral-wool industry, not only would have required a pilot-plant installation capable of producing a large tonnage of mineral wool, but each wool-blowing campaign would have been very expensive and necessitated considerable personnel and equipment. The present laboratory wool-blowing equipment can produce as high as eight wool-blowing campaigns a day. The nature, simplicity, and size of the physical testing equipment permit testing as small a sample of wool as 25 grams and give information as reasonably accurate as in a 40-pound bag of wool. The purpose of this report is to describe the laboratory method of production and the evaluation of the physical properties of small quantities of mineral wool. Considerable work has already been done, and the interest of the public and industry is measured in the number of samples being submitted for testing.

Jan 1, 1948

By J. Croeni

The search for new alloys for application in the atomic energy field had prompted investigation of zirconium-rare earth metal alloys by the Federal Bureau of Mines. In this instance the zirconium-dysprosium system was investigated by melting point, thermal analysis, resistivity, X-ray and metallographic methods. Results indicate a single eutectic system with a peritectoid reaction occurring at 890° C. The eutectic isotherm extends from 30 to 95-percent dysprosium at 1,280° C. Eutectic composition is located at approximately 70 percent dysprosium. Solid solubility of dysprosium in both alpha and beta zirconium is extensive. The extent of solid solubility of zirconium in dysprosium has not been determined. Although zirconium rich alloys exhibit a significant increase in hardness, they can be cold worked extensively. These alloys also appear adaptable to solution heat treatment. Additional investigations concerning corrosion resistance and other mechanical properties are necessary for satisfactory evaluation of these alloys. The superior corrosion resistance of zirconium and the nuclear cross-section characteristics of the rare earth metals have stimulated alloy investigations using zirconium as a base metal. Alloys combining these characteristics present a possible substitute for hafnium as a control rod material. In this particular study dysprosium was chosen as the alloying element, and several series of alloys were used to establish the equilibrium diagram.

Jan 1, 1960

By W. P. Diamond

Coalbeds exhibit a directional permeability, with the maximum permeability oriented parallel to the face cleat. Thus, the most efficient pattern of vertical degasification holes for a coalbed is dependent upon cleat orientation. Surface joints, infrared photolinears, and Ronchi grating photolinears were investigated as potential estimators of subsurface cleat orientation. Cleat orientations were measured in 18 mines, in the Pittsburgh coalbed in southwestern Pennsylvania and northern West Virginia to be used as a standard against which prediction techniques would be evaluated. Two cleat systems with a strong geographic segregation were measured in the study area: N 670 W -N 280 E (950 separation) for the north, and N 76° W -N 17° E (930 separation) for the south. Directional data obtained from the three techniques investigated yielded satisfactory regional predictions of cleat orientation. Analysis of surface joints was the only technique considered sufficiently reliable on a local basis. Prediction of cleat orientation is based on the pairing of the principal directional sets into all reasonable combinations of fundamental systems. The system or systems composed of the most dominant sets nearest to 90° separation are likely to be a reliable prediction of cleat orientation. The most dominant set of the system selected is likely to be the face cleat.

Jan 1, 1976

By W. K. Tolley

This report presents data collected during research by the Bureau of Mines on corrosion of grinding media. Corrosion rates of eight alloys commonly used in grinding media were tested in synthetic mill water using an ultrasonic grinding device especially designed for this work. Electro-chemical measurements showed variations in corrosion rates for these alloys between 9.8 mpy for medium-carbon steels and 0.14 mpy for high chromium white irons. Bureau data are discussed along with data from the literature to indicate that corrosion causes less than 10 pct of the wear of grinding media in commercial grinding mills. A comparison of corrosion rates for various types of grinding media shows that alloying elements and electrochemically active inclusions in steel affect the corrosion behavior of the media.

Jan 1, 1984

By J. B. Gayle

This investigation was conducted by the Federal Bureau of Mines to compare the selectivities of diverse flotation reagents and also of flotation and float-sink methods of separation. Flotation tests, using sodium chloride, an alcohol-type frothing agent, and a kerosine-pine oil mixture as reagents, were made on seven coking-coal samples representing four different beds. The results indicated equivalent selectivities relative to sulfur rejection when entrapment effects were minimized by recleaning the various products. Selectivities relative to ash rejection were also equivalent for some coals; for others, the selectivities of the reagents tended to increase in the order sodium chloride, alcohol-type frother, and kerosine-pine oil. Float-sink tests on these same coals generally gave results indicating better selectivities than those obtained in flotation tests at comparable levels of recovery.

Jan 1, 1960

By K. C. Dean

During the investigation of the occurrence of manganese deposits in western United States, the Bureau of Mines collected 2-ton samples from three oxide manganese ores in the Columbia and Elberta Mining Districts, Tooelo and Juab Counties, Utah. To determine the amenability of these ores to standard ore-dressing methods: of concentration, extensive laboratory tests were made. The Wildcat property, one of those sampled, is 7 miles east of Fairfield, Tooele County, Utah. The ore is described as a replacement deposit and occurs along fracture and bedding planes of shale and limestone. Experimental work was done on a sample taken from a stockpile at the mouth of the shaft. The Wildcat manganese ore is intermediate in grade (25.7 percent manganese) and contains clay as the principal gangue constituent. A high-grade product was obtained with high recovery of Manganese by simple washing.

Jan 1, 1949

By C. J. Walker

The Bureau of Mines undertook a theoretical and laboratory study to determine the feasibility of using ethylene as a tracer for natural gas in underground gas-storage reservoirs. The study indicated that ethylene was a useful gas tracer in underground gas storages. Tracer losses were not excessive. Laboratory tests were conducted at pressures as high as 500 psia in both wet and dry consolidated-sandstone cores, evaluating tracer loss with gas blends containing natural gas with different concentrations of ethylene tracer. Under certain conditions losses were less than 17 percent.

Jan 1, 1966

By H. Kenworthy

The objective of this research was to develop methods and determine conditions under which metallic sulfides with lower boiling points than sphalerite may be removed from zinc sulfide concentrates by volatilization. A higher percentage of extraction of lead, cadmium, and germanium than is common in current practice was sought. The investigation, conducted by the Metallurgical Branch of the Minerals Technology Division, Region VI, showed that, under proper conditions, it is possible to remove over 90 percent of the lead, cadmium and germanium as an enriched sublimate. The uses of lead, and cadmium to a lesser extent, are well-known. Although germanium was discovered in 1886 by C. Winkler, commercial use has been achieved only in recent years. The amount consumed per manufacturer unit is so small that the price of germanium may still be quoted by the gram. The electronic industries have been the chief consumer of this semiconductor. Germanium is sold largely to the fabricator as a dioxide for reduction to metal and subsequent processing into wafers for use in diode and triode electronic tubes. Extensive research at Purdue University during World War II led to the first practical use of germanium.

Jan 1, 1952

By John W. Finch

The present epoch in human history has been variously described as the age of coal, of oil, of iron and steel, and of power. All agree, however, that it is a great industrial period. Power is of course the vital force in the industrial organism; but power is derived chiefly from mineral fuels or from harnessed and controlled water - also a mineral substance although usually not so classified by industry. However, the latent energy of fuels cannot work for men until it is changed to active energy by combustion and until this active energy is converted into motion. This motion is just as indispensible as the energy itself. Likewise, the latent energy of water cannot be utilized until it, too, is converted into motion; out the mechanisms and devices for converting latent energy into motion, as well as the structures in which they are operated, would not be possible without metals and other minerals. Consequently, minerals are fundamental in industrial civilization.

Jan 1, 1938

By P. Kovalchik

The Bureau of Labor Statistics (BLS) classifies hearing loss as a separate illness category. Hearing loss accounted for 11% of all illnesses in 2005 (U.S. Department of Labor Bureau of Labor Statistics, 2006a). According to occupational data for coal mining provided by the Mine Safety and Health Administration (MSHA) from 2000 to 2005, operators that exceeded 100% noise dosage were from only seven types of machines: auger miners, bulldozers, continuous mining machines, front end loaders, roof bolters, shuttle cars (electric) and trucks (Title 30 CFR Part 62, 2000-2005). Roof bolting machine operators rank second among all underground machine operators that exceed 100% noise dose. There are approximately 600 underground coal mines with 3,930 roof bolting machine operators (U.S. Department of Labor, Mine Safety and Health Administration, 2005; U.S. Department of Labor Bureau of Labor Statistics,

Jan 1, 2008

By Deno M. Pappas

The objective of this Bureau of Mines investigation was to identlfy and evaluate alternative binder materials for use in stabilizing and consolidating highly fractured roof along longwall faces and gate roads. The desirable characteristics of a stabilization material were defined, and an extensive search was conducted to find materials satisfying these characteristics. Of 20 materials originally scrutinized, 9 were chosen for laboratory analyses. The laboratory tests evaluated bond strength and tensile strength under both dry and wet conditions. An optimum material was not found. The laboratory analyses indicated two possible candidate materials for longwall stabilization: high-aluminous cement and two-component epoxy; however, the tensile strength of the high-aluminous cement was mediocre, and the epoxy cement is toxic, flammable, and fairly expensive. The potential market demand for an effective and economical stabilization macerial is discussed in the appendix.

Jan 1, 1988

By S. H. Ash

The United States Bureau of Mines has published relatively little on the flooding and unwatering of coal and metal mines. Bulletin 229, Fifty-Nine Coal-Mine Fires, published in 1927, contains several instances of the flooding of mines or sections thereof to extinguish fires but does not describe their unwatering. Report of Investigations 2649, Explosion Hazards Incidental to Unwatering Coal Mines, published in 1924, warned against the possibility of gas accumulations in flooded mines and indicated the precautions to be taken. Report of Investigations 2255, An Unusual Hazard in Reopening Long-Flooded Timbered Metal Mines, published in 1921, told of methane being pocketed and the danger thereof. The flooding of mines originates in many ways. At some mines flooding followed reopening after what was thought to be permanent abandonment; also, explosions have caused some mines to be flooded. Extinguishing fires, accidental encountering of underground streams or flooded old workings, and caves of strata admitting water from underground workings, water-bearing strata, or surface accumulations have also flooded all or parts of mines. Unfortunately, un watering often necessitates much study and causes apprehension largely because experiences in similar situations are not generally known, as few descriptions of successful or unsuccessful methods are available. The job has sometimes been contracted for outside the local management involved and has become a matter of record for the contractor only. As the cost-plus contract system often employed in the past is now known to be expensive, careful managements elect to handle the problem themselves, in line with the general policy of cutting expense where possible. This report describes specific in-stances of successful unwatering by operators.

Jan 1, 1933

By C. L. Klingman

In extracting helium from natural gas at Bureau of Mines helium plants, a continuous analysis of the helium content of inlet and outlet gas streams is required to determine extraction efficiency. An analyzer, using established principles of gas chromatography to effect the analysis, has been developed by the Bureau of Mines to meet this need. It will record the helium content of inlet or discharge gases from helium-extraction plants every five minutes, continuously, without the attendance of an operator. A 25-inch column of activated charcoal is used as a partitioning agent; nitrogen is the carrier gas; and a hot-wire, thermal-conductivity cell is the detector. A 1.0 mv, strip chart indicates the unbalance of the detector cell, Sample size is 0.37 cc, and carrier gas flow rate is 75 cc, per minute. Significant improvements in helium extraction have been demonstrated by using the chromatograph in three helium-extraction plants.

Jan 1, 1961

By J. E. Tress

The Bureau of Mines prepared submicron tungsten powder by reducing tungsten hexachloride with hydrogen. The particle diameters of the resulting tungsten powders ranged from 0.015 to 0.046 micron. Within the limits of the variables investigated, no clear-cut correlation was found between process conditions and final size of the powder. Oxygen was the major contaminant in the product; being present both as an adsorbed gas and as suboxides of tungsten. Studies showed that the powder yielded compacts of approximately 45 per-cent of theoretical density when compacted mechanically. Low-temperature sintering produced more rapid densification in these compacts than in compacts prepared from conventional powders. Adding up to 20 percent ultrafine powder to conventional tungsten powder caused an increase in density upon compaction with maximum densification occurring at approximately 12 percent ultrafine powder.

Jan 1, 1966

By D. G. Lee

Diesel particulate matter (DPM) often contains small amounts of metal as a minor component but this metal may contribute to adverse health effects. Knowledge of the mechanism for particle formation as well as the size preference of the trace metals is critical to understanding the potential for health concerns. To achieve this, the size and the composition of each particle should be optimally measured at the same time. Single particle mass spectrometer (SPMS) would be the best tool for this objective. In this paper, we therefore will introduce new findings about the mechanism and distribution of the trace metals in DPM, derived from a study where an SPMS was used to analyze freshly emitted DPM. KEY WORDS : Single particle mass spectroscopy, Diesel particulate matter, Characterization, Metal contents

Jan 1, 2006