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By James D. Noll, M. Eileen Birch

A monitoring method for diesel particulate matter was published as Method 5040 by the National Institute for Occupational Safety and Health (NIOSH). Organic and elemental carbon are determined by the method, but elemental carbon (EC) is a better exposure measure. The US Mine Safety and Health Administration (MSHA) proposed use of NIOSH 5040 for compliance determinations in metal and nonmetal mines. MSHA also published a rule making for coalmines, but no exposure standard was provided. A standard based on particulate carbon is not considered practical because of coal dust interference. Interference may not be a problem if an appropriate size-selective sampler and EC exposure standard are employed. Sub micrometer dust concentrations found in previous surveys of nondieselized, underground coal mines were relatively low. If a large fraction of the sub micrometer dust is organic and mineral matter, sub micrometer EC concentrations would be much lower than sub micrometer mass concentrations. Laboratory and ?eld results reported here in indicate the amount of EC contributed by sub micrometer coal dust is minor. In a laboratory test, a sub micrometer EC concentration of 31µg m 3 was found when sampling are spirable coal dust concentration over three times the US compliance limit (2mg m3). Laboratory results are consistent with surveys of nondieselized coal mines, where EC results ranged from below the method limit of detection to 18µg m 3 when size-selective samplers were used to collect dust fraction shaving particle diameters below 1.5µm sub micrometer EC concentrations were ?7µg m3. In dieselized mines, sub micrometer EC concentrations are much higher.

By G. E. McElroy, A. S. Richardson

"Experiments in the determination of friction factors for fan-pipe installations were carried on in a Butte mine during the fall and winter of 1922-23, under a cooperative agreement between the Bureau of Mines and the Anaconda Ccpper Mining Co. The results have been summarized in a separate paper,*** and this report, which is one of several giving more detailed data, discusses the methods used and the application of the results to fan-pipe practice.The use of canvas and galvanized-iron pipe, 8 to 20 inches in diameter, with small fans, usually electrically driven blowers, is an important factor in the ventilation of metal mines and is increasing in coal mines and long tunnels. In the Matte district the standard installation is an electrically driven small blower fan and 8 to 16 inch canvas pipe.The application of available data on friction losses in sheet-metal pipe to mine installations was doubtful, and very little has been published on canvas pipe, except general statements that the friction looses are greater than in galvanized-iron pipe. Experiments by Weeks and others,**** who determined friction losses under laboratory conditions for a few typical materials used in mine equipment, supported the statements.In 1918, one of the authors (Richardson) conducted tests for the Anaconda Copper Mining Cc. on the friction losses in canvas-pipe systems and the beet type of centrifugal blower for use with such pipe lines. He obtained the average total resistance per unit of length in use, without reference to the variable conditions of the lines. The results were of great value in developing more efficient equipment for average service conditions, and indicated that average friction losses for the commercial canvas tubing then used by the company were equal to or lees than these given for galvanized-iron pipe. Later on, the particular canvas tested was discarded for a heavier and more service-material."

Oct 1, 1923

By David Schlain, C. B. Kenahan, F. X. McCawley

The electrodeposition of protective coatings of tungsten from a sodium and lithium borate - tungstate - tungstic oxide fused salt electrolyte was investigated . Soluble tungsten anodes were employed . Deposits were made on molybdenum , Carpenter 20 stainless steel , Inconel , and nickel . An atmosphere of argon was maintained around the electrolytic cell , and the electrolyte was stirred by rotating the cathode . Thick deposits of tungsten (up to 26 mils ) were made at a temperature of 900 ° C and cathode current densities of 0.3 to 0.4 ampere per square inch with high current efficiencies . The effects of variations in temperature , current density , electrolyte agitation , and tungstic oxide content of the electrolyte and of the presence of impurities such as moisture , air , iron , and nickel were investigated .

Jan 1, 1964

By Deno M. Pappas

The purpose of this Bureau of Mines study of U.S. roof and rib (roof- rib) accident statistics and related accident costs is to define current accident trends (1980-84) associated with fatal and nonfatal roof-rib fall accidents. Data were retrieved from a data base containing all recorded U.S. mining accidents, then sorted and normalized utilizing a computer software program. The statistics indicate that roof-rib accidents have significantly declined in the 5-yr study period. Moreover, they indicate that there have been increases and/or patterns of roof-rib accidents associated with specific mine characteristics, such as seam height, mine size, geographic location, and seasonal variations. Also, roof-rib injury characteristics produced pattern changes involving worker activity, lost workdays, types of injury, and severity of injury. A conservative estimate indicates that there has been a 30% adjusted increase in the cost of a roof-rib accident over the 5-yr study period.

Jan 1, 1987

By Ludwig Schmidt

The consumption of gasoline in the United States varies materially with the seasons; during some of the summer months it exceeds the rate of production and in the other seasons the production of gasoline exceeds the consumption, The usual practice of the larger refiners is to store surplus stocks during the winter season in order to meet the heavy demands during the summer months. The following table shows the stocks of gasoline at refineries on the last day of April for the past five years: 1919 593,616,170 gallons 1920 643,5526644 " 1921 747,222,900 " 1922 892,567,766 " 1923 1,336,417.871 "

Jan 1, 1923

By H. R. Babitzke

The purpose of this investigation was to evaluate the potential of columbium-hafnium alloys as structural materials for use at elevated temperatures. The work described in this report was conducted to determine the properties of columbium-hafnium alloys and to select the more promising ones for further improvement. Properties determined in this report were machinability, hardness, workability, tensile strength, and oxidation resistance. Ten ingots, ranging from 100 percent columbium to 70 atomic-percent hafnium, were prepared and subjected to tests. The test results showed that the alloys with 33 and 50 atomic-percent hafnium were superior in workability, strength, and oxidation resistance. For the alloy series tested, the strength and hardness values increased with the increasing hafnium content. Maximum values were reached with 50 atomic-percent hafnium. The oxidation resistance was poorest at the 1 atomic-percent hafnium level but improved with increasing hafnium content through 70 atomic-percent. Eight of the ten ingots were fabricable at room temperature. The two remaining ingots, those with 5 and 10 atomic-percent hafnium, required hot-working.

Jan 1, 1962

By J. C. Duchon

The use of extended workdays or compressed workweeks (regular shift lengths exceeding 8 h) is attracting growing interest in many industries using continuous operations. While extended workdays promise increased worker satisfaction due to more days off, including weekends and holidays, there are legitimate concerns about the potential effects on the health and safety of such a schedule. The U.S. Bureau of Mines (USBM) conducted a study at a Canadian underground copper, lead, and zinc mining operation that was designed to study the safety and performance implications of extended workdays. Measures were taken before and after a change from the old 8-h continuous schedule to the new 12-h continuous schedule, including behavioral performance measures to analyze perceptual-motor changes, continuous heart-rate monitoring and aerobic capacity to measure physical fatigue, a variety of self-report questionnaires to measure perceived adaption and satisfaction with the new schedule, and pulmonary-respiratory measures to examine air contaminant exposure. Based upon the overall acceptance of the new schedule by the workers and lack of change in fatigue-sensitive behavioral and physiological performance measures, this study recommends that the mine retain the 12-h schedule. However, certain precautionary measures are suggested to insure the safety of the workers.

Jan 1, 2010

By Greenwald, H. P

The Bureau of Mines has been conducting experiments on the explosibility of coal-dust in the experimental mine for more than 17 years. The results have been published from time to time3, and a forthcoming technical paper4 will summarize the results and discuss them in some detail. The present paper will be limited to a statement of the more important facts that these researches have discovered.

Apr 1, 1929

By R. Dell Davidson

This report contains the results of the work performed by Dayton T. Brown. Inc., Testing Laboratories, Bohemia, New York, under the Department of Interior, Bureau of Mines, Contract J0166089 entitled "Performance Testing of Air-Line Linking Components." The objectives of the program consisted of the following: 1. To conduct engineering tests that will provide data to recommend the performance criteria for air hose and piping connections. 2. To determine the requirements for restraining devices which are used to comply with MESA Health and Safety Standards 55, 56, 57,13-21.

Jan 1, 1978

By M. J. Reasor, M. DiMatteo, J. M. Antonini, K. Van Dyke, Z. Ye

"The inhalation of silica has been shown to produce a dramatic inflammatory and toxic response within the lungs of humans and laboratory animals. A variety of cellular and biochemical parameters are used to assess the silica-induced lung injury. The purpose of this paper is to introduce the use of luminok:Jependent chemiluminescence as a new method to study inflammation in both phagocytic cells and lung tissue recovered from silicaexposed animals. Chemiluminescence, or the emission of light, accompanies the release of reactive forms of oxygen when phagocytic cells are challenged. In this study, male Fischer 344 rats were intratracheally instilled with either silica (10 mg/100 g bw) or saline vehicle. One day after the instillations. a marked increase in the chemiluminescence was observed in the lung tissue and bronchoalveolar lavage cells recovered from the silica- treated animals when compared with the saline controls. The light reaction was markedly decreased by either superoxide dismutase or N-nitro-Larginine methyl ester hydrochloride. Superoxide dismutase is involved in the enzymatic breakdown of superoxide anion. while N-nitro-L-arginine methyl ester hydrocholoride, a nitric oxide synthase inhibitor, prevents the formation of nitric oxide. When superoxide anion and nitric oxide react. they form the highly oxidizing substance peroxynitrite. This study then implicates peroxynitrite as an agent that may be responsible for some of the oxidant lung injury that is associated with silica exposure. The use of luminol-dependent chemiluminescence may prove valuable as a method to measure the earliest events in the inflammatory process. and may be an adjunct in studying the mechanisms that produce inflammation. - Environ Health Perspect 102(Suppl 10):37-42 (1994) IntroductionResearch on inflammation has not produced a method that links the initial events of the process to the controlling events. Rather, a variety of parameters are measured that are the result of and not the basis of the inflammatory reaction. Parameters such as tissue weight, edema, blood flow, enzyme and protein release, or production of metabolites (prostaglandins, leukotrienes) have been used extensively. A method is needed that could be applied to cells of a particular type, groups of cells of different types, and even tissue, in an attempt to study the kinetics of the inflammation as well as being sensitive enough to monitor the early events of the process . Since inflammation is so complicated, the relationship between the control of the initial events and the oxidation process has never been explained nor studied in any derail."

Dec 1, 1995

By A. B. Needham

Graphite is a raw .material of considerable importance in both waxy and peace. Two types of graphite, classified according to particle size as flake and fines, are used, but the former is in much greater demand. The principal wartime use of graphite is in the manufacture of crucibles for melting brass and special alloys of copper and steel. Other uses in both peace and war are as lubricants, for foundry facings, and in paints, electrodes, batteries, motor and generator brushes, and a variety of other commodities. . This paper describes the operations of the Southwestern Graphite Co. of Los Angeles, Calif., which produces both flake and fine graphite from a property in Burnet County, Tex.

Jan 1, 1946

By W. H. Ode

Because trade increased among various nations after World War II, the Coal Committee of the Economic Commission for Europe established a Classification Working Party in 1949 to develop an International system for classifying coal. Although national classification systems existed, they had been developed in accordance with characteristics of domestic coals without reference to coals of other countries. Terms for describing similar or identical coals differed in each nation. This caused confusion in evaluating coals shipped in international trade and also hampered exchange of technical information on problems of coal utilization. Experts4/ participating in the classification project early in their work agreed that two systems should be formulated, one for the higher rank coals or so-called "hard" coals in European terminology and the other one for the lower rank coals, the latter designated mainly as brown coals and lignites in the various countries. Rank refers to the degree of metamorphism (progressive alteration) in the natural coalification series from lignite and brown coal to anthracite. The system for classification of hard coals was published late in 1956 as a document of the United Nations.5/ Results of a study for applying this system to American coals were published in 1958.6/

Jan 1, 1960

By Paul Hatmaker

A primary, function of the Bureau of Mines is to encourage elimination of waste and the most profitable use of mineral raw materials. In line with this objective the Bureau has frequently stressed the importance of waste utilization at stone quarries. From time to tine studies both technical and economic in character have been made of problems pertaining to the most efficient use of natural, stone, particularly that which may be classed as a by-product of the higher grades of dimension stone. Every quarry producing ornamental or building stone yields large quantities of material that for one reason or another is unsuited for high-grade products, even though a great deal of work has been expended upon it more or less unavoidably. It is obviously good judgment to sell this odd-sized or off-grade stone at whatever price can be obtained rather than to spend more money to place it on the waste dump. In many cases, however, a really profitable side line has been developed.

Jan 1, 1933

By Robert A. Jankowski

The U.S. Bureau of Mines, in cooperation with the Mine Safety and Health Administration (MSHA) and the mining industry, has identified and demonstrated the effectiveness of several improved face ventilation techniques for longwall mining systems. These include the following: identifying improved techniques for measuring face ventilation parameters on longwall sections, installing curtains at the intake end of the longwall face to maximize usage of the primary airflow, identifying optimum face airflow rates for maximizing dilution effects, and coursing the primary face intake from tailgate to headgate to minimize outby airflow contamination. Application of these techniques throughout the mining industry should reduce the health hazard associated with excessive exposure to respirable coal mine dust.

Jan 1, 1993

By Louis A. Panek

An improved centrifugal-testing apparatus has been designed and built in the Bureau of Mines laboratory at College Park, Md., which is unique in that it incorporates the use of resistance gages to measure directly the strains in a rotating model without testing it to failure. Owing to this feature, a more rapid testing method can be used; furthermore, model materials need not be restricted to those of the prototype. The behavior of any structure in which strains of significant magnitude are produced by its own weight may be studied in a small model subjected to simulated gravity loading. The model is rotated in a centrifuge to induce in it centrifugal forces, which, like the gravitational forces in the full-size structure, act on the volume elements and are proportional to the masses thereof. Centrifugal testing is, therefore, applicable to the design of mine openings and to the study of similar ground-control problems. It constitutes an experimental method for determining the state of strain in a structure for which analytical methods are excessively laborious or even impossible. In previous applications of centrifugal testing by other investigators, the models usually were tested to failure, and the analysis was made from-the type of break produced. The models were made of the same materials as the proto-type, and the test results were applied only to the particular prototype represented by the model. Beam deflections were measured from photographs of the rotating model, but no means was employed either to determine the actual distribution of stress in the model or to determine quantitatively the degree of restraint imposed on the ends of the loaded model beam, that is, to determine whether the loaded model behaved as a beam with rigidly fixed ends or as some other type of beam. With the apparatus described, it is possible to determine the state of strain, and thus the boundary conditions, in a rotating test model weighing up to 90 lb., which can be subjected to centrifugal forces up to about 2,600 times the force of gravity. The load-strain relationship, applicable directly to the prototype, can be determined from a Single model test. The test results can be presented as quantitative relations between the loads, strains, and dimensions and mechanical proper-ties of the structural members and can be applied to any prototype, whatever its component materials, that satisfies the similarity requirements.

Jan 1, 1952

By H. J. Kelly

[This investigation of the refractory properties of seven Pacific Northwest chrome ores and concentrates has shown that five of the ores and one of the concentrates are suitable for making refractories and that all may be used in combination with high-grade chromite. The specific objectives of the investigation were to determine the inherent physic al and chemical characteristics, to shapes using each of the chrome ores and concentrates, to compare the refractory qualities of the laboratory-prepared with commercial chrome refractories. As far as possible, standard tests were used as criteria.]

Jan 1, 1952

By Carl L. Bieniewski

U.S. molybdenum production increased fivefold from 18.2 million pounds in 1946 to 90.5 million pounds in 1966, and constituted 87.3 percent of the total free world supply in the 1946-66 period. Mining development in other free world countries in the next few years may reduce the magnitude of the U.S. position, although similar development planned for the United States may counteract some of the relative gains by those countries. In 1966 two-thirds of the reported molybdenum consumption in the United States by end uses was as an alloying element in steel. Molybdenum also has important use as an alloying element in iron and high-temperature alloys. Consumption of molybdenum metal for making fabricated parts has increased in the past few years, especially in the space and nuclear industries. Molybdenum compounds are used mainly for making pigment, catalysts, and lubricants. Based on producer reports of shipments of primary products to domestic customers, U.S. consumption of molybdenum increased from 16.5 million pounds of molybdenum in 1946 to 65.6 million pounds in 1966. U.S. molybdenum reserves are now estimated to be 5.9 billion pounds of recoverable molybdenum, an increase of 2.1 billion pounds above previous estimates. Molybdenum ores account for 71.4 percent of the reserves, copper ores for 22.3 percent and copper-molybdenum, tungsten, and uranium ores for 6.3 percent. Several methods for predicting future demand are illustrated and estimates of demand using these methods were made for 1975. Based on present capacities and announced company plans for future developments, estimates of annual production were made for 1967 through 1975 for the United States, Canada. Chile, Peru, and the free world. These data indicate that molybdenum production in 1975 for the free world is expected to be 246 million pounds with the United States producing 68.2 percent and Canada, Chile, and Peru 30.3 percent.

Jan 1, 1970

By William J. Campbell

This Bureau of Mines report describes a study conducted to determine the relationship of mineral habit to particle size and shape characteristics for prismatic, acicular, fibrous, and asbestiform varieties of tremolite. Particle measurements were made with the petrographic microscope at X 1,250 and the scanning electron microscope at magnifications up to X 10,000. All of the varieties of tremolite, upon Wiley milling, produced a significant percentage of particles that meet the Federal regulatory criteria for counting as asbestos fibers. However, only the asbestiform variety gave milled particles that fell into a size range of >10 µm in length and <0.5 µm in width; some medical scientists consider this range significant for production of adverse health effects.

Jan 1, 1979

By F. S. Wartman

The presence of magnetite, either dissolved or suspended as solid crystals, in slags from the copper reverberatory furnace is a frequently mentioned cause of an abnormally high copper content in those slags. The presence of this oxide in the slag is to be expected, since it is present in appreciable amounts in both converter slag and roaster calcine which comprise a considerable proportion of the furnace feed. Magnetite is also a product of some of the furnace reactions. These abnormal losses result in several ways. Magnetite is supposed to favor the formation and retention of copper ferrite, in the slag. Crystals of solid magnetite suspended in the slag are objectionable-because they make the slag less fluid and often entrap globules of matte. Frequently these crystals settle into a layer at the slab-matte interface which may have such mechanical strength as to create a false bottom and interfere with furnace operation by preventing separation of matte from slag. Magnetite may, by crystallizing on the furnace bottom, build the bottom to such a level that the furnace can no longer be operated.

Jan 1, 1928

By G. B. Atkinson

The Bureau of Mines investigated a method for increasing the leaching rate of bulk superalloy scrap to facilitate recycling and recovery of critical metals such as Ni, Co, and Cr. Three superalloys were investi- gated, the cast-nickel-base superalloy IN-738, the wrought-nickel-base superalloy Rene-41, and the cast-cobalt-base superalloy Mar-M-509. Superalloys melted with 20, 30, 40, and 50 pct Al metal to form inter- metallic compounds were easily crushed to a convenient particle size and reacted rapidly with acid solutions which dissolved the metals. For example, leaching 1/2-in pieces of unalloyed IN-738 with excess 6N HC1 at 95° C for 2 h dissolved about 0.5 pct, while leaching 10 g of minus 20-mesh 30 pct Al-70 pct IN-738 with excess 6N HC1 at 95° C for 2 h dis- solved 96.2 pct.

Jan 1, 1983