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By W. M. Myers

The U. S. Bureau of Mines conducted an investigation to determine the cause of the deterioration of Portland cement during storage and transportation , and to discover a means of preventing it . All available printed sources of information on this subject have been examined and a bibliography has been compiled . The subject has also been discussed with the leaders in the cement industry ; the present report is the result of their cooperation , and is based principally on information thus obtained . Deterioration of Portland cement during storage over any considerable period of time has long been noted ; closely related to it is deterioration of cement during transportation, which involves not only the time factor of storage but also exposure to varied climatic conditions . Deterioration in both cases is due to hydration of the cement by absorption of moisture from a humid atmosphere , or by exposure to actual rain-fall . After hydration cement possesses no cohesive power ; the degree of deterioration is directly proportional to the degree of hydration . The amount of deterioration of Portland cement during storage has been accurately determined in an investigation by the Structural Materials Research Laboratory , in cooperation with the Portland Cement Association . Cement stored in a shed in cloth sacks retained 80 per cent of its original strength after three months storage ; 71 per cent after six months ; 61 per cent after one year ; and 40 per cent after two years . The deterioration of Portland cement during storage and transportation was noted particularly in France during the World War . Information concerning cement used by the American Expeditionary Forces was furnished by Lt. Col. H. S. Spackman and Major E. C. Eckel , U. S. R. , who had charge of practically all matters concerning cement used by the A. E. F. The cement used by the A. E. F. came from the following sources : 42,000 tons was French , Swiss , and Spanish cements ; 120,000 tons was English cement ; 55,000 tons made in plants operated by the A.E.F .; 500 tons ( Not over) from America . Deterioration was most marked in cement from the first source .

Jun 1, 1922

By W. J. Fene

A comprehensive study of all bituminous coal-mine fatalities occurring in Pennsyl¬ vania during the 5-year period, 1926-1930, was made to try to determine the factors that in¬ fluence accidents which cause these fatalities. During this study some two thousand reports of fatalities were reviewed, and pertinent information as to causes and influencing factors were tabulated therefrom. These tabulations are discussed in detail, and in some instances recommendations are made with a view to reducing the hazards in certain classes of these accidents.

Sep 1, 1931

By Diana K. Schimmelpfennig

Assessment of revegetation success on mined lands is a difficult, time consuming task and has been the subject of a number of controversies. Present regulations require that both plant cover and aboveground plant biomass be measured for use in making that assessment. Of these two variables, biomass is the most time consuming to measure and requires destructive sampling, a most undesirable requirement on fragile, recently revegetated areas. On the other hand, plant cover can be estimated using the point-frame method which is relatively nondestructive. In addition, vegetation can be sampled more uniformly with the point frame and in less time if species composition measures are to be made. A study was done to evaluate the predictability of aboveground biomass production on revegetated mined sites and adjacent native prairies using plant cover estimates made with the point frame method. The predictability of biomass production by cover estimates bears on the need for both measurements in assessing revegetation success. In general, a positive, statistically, significant correlation was demonstrated between plant cover (estimated by the point frame) and aboveground biomass (estimated by the harvest method) regardless of community type (mined or native), species composition, diversity or level of biomass production. However, the latter did have their effects on the relationship and must be accounted for in any predictive equations (that is to say, the predictive equations must be considered site-specific). Considering the relationship observed between the two parameters, cover estimation may be a sufficient indicator of revegetation success, especially where time and minimization of disturbance are critical.

Jan 1, 1982

By Masami Hayashi

Cost evaluations were made for five processes for producing 100,000 tons of electrorefined copper per year from a chalcopyrite concentrate. The processes were (1) conventional smelting with all furnace gases vented to the atmosphere; (2) conventional smelting with converter gases routed to an acid plant and reverberatory gases vented to the atmosphere; (3) conventional smelting with converter gases routed to an acid plant and reverberatory gases to a citrate system plant; (4) conventional smelting with all furnace gases routed to a citrate system plant; and (5) a modified smelting process in which the concentrate is roasted before being charged to the reverberatory furnace, with roaster and converter gases routed to an acid plant. The total fixed capital costs of the plants were estimated as (1) $56.7 million, (2) $77.4 million, (3) $87.2 million, (4) $73.9 million, and (5) $77.0 million, respectively. Total S02 removal from stack gases as sulfuric acid or sulfur for each process was (1) none, (2) 66 percent, (3) 99 percent, (4) 98 percent, and (5) 78 percent. Assuming no credit for byproduct sulfur or sulfuric acid, total operating costs per pound of electro-refined copper produced were estimated as (1) $0.081, (2) $0.103, (3) $0.119, (4) $0.111, and (5) $0.103, respectively.

Jan 1, 1974

By G. R. Hopkins

The average gravity of the total crude petroleum produced in the United States during; the year 1927 was 32.2° A. P. I., or 0.864 in terms of specific gravity. A similar study, made by the U. S. Geological Survey in 1921, gave the average gravity at that time as 32.0.° To one who is accustomed to thinking of crude petroleum in terms of Oklahoma-Kansas and North Texas trades it may be surprising that the average gravity for the entire country is no higher than 32.20. The chief reason for this apparent discrepancy lies mainly in California production, which in 1927 amounted to over 25 per cent of the total, but which had an average gravity of only 24.10. A factor of less importance was Arkansas, which, though on the decline as a producing State, exerted a material effect by reason of its average gravity of 21.6°, the lowest for any State. In view of the heavy production of light crude in the Seminole area of Oklahoma during 1927, it would appear that the average gravity should have shown more than a 0.2 per cent gain over 1921. That this did not occur was due to the fact that in the interim between 1921 and 1927 important heavy oil discoveries were redo, notably the Smackover field of Arkansas.

Jan 1, 1929

By H. E. Powell, T. E. Hill, W. A. Calhoun

The object of this investigation was to determine the effectiveness of certain cationic flotation collectors , Ethomeens , in recovering fine particles of lead minerals from mill tailings at a grade equal , at least , to that of the mill feed ( 1.7 percent lead ) . The Ethomeens , derived from tertiary amines having one fatty alkyl group and two polyoxyethylene groups attached to the nitrogen , were evaluated by bench- scale flotation tests . The 14 Ethomeens tested consisted of four groups : Coco amine , soybean amine , tallow amine , and stearyl amine . The best results were obtained with coco amine C / 12 , soybean amine S/ 15 , tallow amine T / 12 , and stearyl amine 18/20 . From a feed containing 0.23 percent lead , rougher concentrate grades of 2.12 to 3.89 percent lead were obtained , with recoveries of 17.3 to 27.5 percent of the total lead . Some of the lead mineral particles recovered had diameters of less than 1 micron . In comparative tests , the Ethomeens , or polyethoxylated amine types of cationic surface active agents , were more selective than conventional xanthate collectors for flotation of slimed lead minerals .

Jan 1, 1964

By Parry. V. F.

"INTRODUCTION Coal is a compressed mass of heterogeneous, macerated, metamorphosed plant remains that have collected in the earth's crust. Probably no two beds of coal have identical properties, and different parts of the same bed may vary considerably when measured by some of the many empirical tests that have been developed to classify or differentiate the properties of coal. Because of this great variability in properties, the commercial processing of coal to produce coke and byproducts has developed largely as an art based on experience, rather than as a science. Much empirical chemical research, however, has been and is being conducted on coal carbonization, and this work is of practical value in obtaining larger yields of gas and byproducts and in the improvement of the physical properties of the coke.Both ultimate and proximate analyses have been used for correlating purposes. 3/ In the United States the proximate analysis is used for the classification of coal according to rank and grade. The proximate analysis can be employed usefully in the coal—carbonization industry because separation of the combustible matter of coal into volatile matter and fixed carbon is, in fact, a small carbonization test conducted on 1 gram of coal heated in a platinum crucible.Small—Scale Laboratory Coking Tests,Many empirical tests have been devised for determining the coking properties and measuring the yield and quality of gas and byproducts obtainable from various coals. These tests, made on samples ranging from 25 grams (about 1 ounce) to 5 kilograms (11 pounds), furnish information that is roughly proportional in practical value to the size of the sample carbonized. However, the cost of the carbonization test also increases with the amount of the sample, so that for preliminary surveys of a number of coals, samples of 25 to 1,000 grams usually are employed."

Dec 1, 1939

By Martin Hertzberg

The early and reliable detection of the self-heating of combustible substances in mines is of considerable importance to the mining community. This Bureau of Mines report describes the results of a variety of studies of incipient combustion and its detection. Heated samples of coal, wood, and various polymers were used to evaluate the relative sensitivities of several types of detectors. The laboratory results indicate that submicrometer particulate detection is the most universal and sensitive method. Carbon monoxide detection was as sensitive as submicrometer particulate detection for pyrolyzing coal but was relatively insensitive to pyrolyzing wood or plastics. The conventional type of ionization smoke detector was the least sensitive for coal and of intermediate sensitivity for wood and plastics. Self-heating experiments with Pittsburgh seam coal piles of varying particle sizes gave ignition temperatures of 170° C for 4-to 7-µm dust, which increased monotonically with particle size. The measured heating rates were compared with data from an adiabatic calorimeter to obtain preexponential rate constants. The preexponential rate constants varied linearly with the surface area per unit mass of sample as would be expected for heterogeneous surface oxidation. The propagation behavior of ignition waves and the overall self-heating appears to depend critically on the magnitude of the convective flows induced, which counteract the depletion of oxygen in the void spaces of the pile. Classical theories of thermal ignition require substantial modification to be applied reliably to such cases.

Jan 1, 1977

By C. A. Herbert

This paper sets forth the hazards of accumulations of explosive mixtures of methane and air due to inadequate ventilation, the causes of which are discussed as follows: 1. Lack of well-maintained air courses. 2. Air losses due to leaky stoppings, trap doors, and overcasts. 3. Faulty mining methods. 4. Poor supervision. A modified plan of room-and-pillar panel mine development is suggested, which, it is believed, will eliminate many off the hazards of gas accumulations inherent in the present method of mine development. It is also suggested that some water-proofing agent be used on the roof of permanent air-course entries in conjunction with roof bolting to eliminate the detrimental effect of the moisture-laden atmosphere during summer and thus prevent serious roof falls.

Jan 1, 1953

By D. Harrington

"In at least three out of every four working faces in metal mines there is no attempt made to cause air circulation other than by use of compressed air, and in at least nine cases out of ten the compressed air is released merely by opening, or partly opening, the valve and allowing the compressed air to escape through open air hose used to convey the compressed air to the drilling machines. Usually no blowers are in use during periods of drilling, as the exhaust from the drill provides cool, comparatively fresh air for the driller; however, in some instances, the compressed-air line is provided with a tea connection, which permits taking air for the drill from one side of the tee, and air for ventilation through a separate hose used as a blower, simultaneously with drilling.Table 1 contains temperature and humidity data as to compressed-air blowers from open end of air hose at 36 working places in eleven metal mines of four States, embracing the mining of gold, silver, copper, lead and zinc ores, and at horizons ranging from 500 feet below the surface to as low as 4900 feet.It is noticed that the ordinary air surrounding the worker at the face gives an average wet bulb temperature of 81.7° F. for the 36 working faces, with 84.7° F. dry bulb and 87.2 per cent relative humidity. The average wet bulb tem¬perature of 36 readings at these working faces of compressed air at the end of the,hose as the air issues from the hose was 67.4° F., or 14.3 degrees lower than the average wet bulb readings of the air of the working places; however, the average dry bulb temperature of the 36 readings of compressed air as it issued from the end of the hose was 79.7° F., or only 5 degrees less than that of the general air (84.7°); the relative humidity was 51.1 per cent as against 87.2 per cent for the surrounding air. Readings were taken in five raises, seven crosscuts, ten drifts and 14 stopes.It will be noted that the velocity or movement of the general atmosphere at each of the entire 36 working faces, was found to be practically imperceptible; this might readily be inferred since compressed air is rarely used on blowers if there is adequate circulation of the general air of the place. Where rook temperatures could be obtained readily, they are shown; it is noticeable that the dry bulb temperature of the air of the working place varies little from the rock temperature, and that the dry bulb temperature of the compressed air as it issues from end of air hose varies only a few degrees from the temperature of the surrounding rock; in some instances the dry bulb temperature of the compressed air as it issued from the end of the air hose was higher than the rock temperature or the dry bulb temperature of the surrounding air."

May 1, 1921

By D. K. Deardorff

The purpose of this work was to investigate the hafnium-carbon phase diagram. Alloys used to study this system were prepared from high-purity components by both consumable-and nonconsumable-electrode arc melting. Data for the diagram were obtained on the alloys by metallography, optical pyrometry, thermal analysis, heat treatment, and X-ray diffraction. The data indicate that a carbide compound occurs over considerable range of composition, and that one of each of the following types of reactions occurs in the hafnium-carbon system: Peritectoid, peritectic, and eutectic. The maximum melting temperature of hafnium carbide is 3,840° C at 49 to 50 atomic percent carbon, and the composition range of hafnium carbide at temperatures of 2,150° to 2,380° C is from 37.0 to 48.5 atomic percent carbon. The hafnium a-S transformation temperature is raised on alloying with carbon from 1,750° to 1,890° C, where a peritectoid reaction isotherm occurs. Alloying hafnium with carbon increases the hafnium melting temperature from 2,190° to 2,250° C, at which temperature a peritectic reaction occurs. Hafnium carbide and carbon react at 3,055° C to form a eutectic of 68.3 atomic percent carbon.

Jan 1, 1967

By Earl T. Hayes

For several years the Northwest Electrodevelopment Laboratory of the Bureau of Mines, in cooperation with the Air Materiel Command, U. S. Air Force, has been studying zirconium alloys. A preliminary survey of these alloys has been completed and reported as a Bureau of Mines Report of Investigations. 4/ Originally the purpose was to determine the suitability of zirconium alloys in medium-temperature applications. However, data also were obtained on other properties of these alloys, and later the scope was broadened to include amore detailed investigation of a selected group. The zirconium-titanium system was one of those chosen. The Bureau of Mines has been instrumental in the commercial development of both of these metals and has constructed pilot plants for the production of titanium at Boulder City, Nev., and for zirconium at Albany, Oreg. Both elements are in subgroup A, fourth series of the periodic table, and therefore have many properties in common. Since both have similar atomic structures and lattice dimensions the possibility of extended mutual solubility seemed likely. Inc transition-point diagram of Fast indicated that the two metals are completely miscible in all proportions in both the alpha and beta forms.

Jan 1, 1951

By Charles M. McCulloch

This Bureau of Mines report discusses the principles of using computers to draw maps and plot geologic data of mining areas. The types of maps that can be drawn by a computer are reviewed, using as examples two separate areas where poor roof and gas emissions caused mining problems. Such maps can be used not only to help identify problem areas, but also to predict areas where problems could occur, thus giving mine operators time to work out solutions prior to mining. The average cost of a computer-drawn map for a mine property is less than $100, including computer time and man-hours for data preparation.

Jan 1, 1976

By W. M. Dressel

A simple, reliable field test for beryllium in rocks has been developed by the Rolla Metallurgy Research Center of the Federal Bureau of Minas. A small portion of the pulverized rock is fused with a sodium carbonate-sodium hydroxide flux in a wire loop. The fused mass is dissolved in water, a few drops of quinizarin solution are added, and the solution is viewed under ultraviolet light. A pink-to-orange fluorescence reveals the presence of beryllium in a sample containing as little as 0.013 percent beryllium (0.26 percent beryl). INTRODUCTION New and potential uses for beryllium make necessary a more intensive search for this metal, which is so similar to aluminum in its chemical reactions that it is not separated from aluminum in ordinary chemical analyses. The principal ore mineral of beryllium is beryl, a beryllium-aluminum silicate, which contains only 5 percent beryllium. This mineral is so similar to quartz in appearance that it is not always possible to distinguish one from the other in the field. While the distinction may be made easily with a petrographic microscope, few prospectors have access to such an instrument, and fewer still know how to use it.

Jan 1, 1960

By Ann G. Kim

Studies on the initiation and propagation of mine fires have dealt almost exclusively with coal. It has been assumed that the self-heating potential of carbonaceous shales and coal wastes is relatively low. However, in abandoned coal mines and waste banks, initiation and propagation of fires may be strongly dependent on the self-heating tendency of these materials. The purpose of this study was to compare the self-heating probability of carbonaceous shales and coal wastes to that of coals. This study utilized a modified differential thermal analysis method, in which the combustion furnace temperature was the reference to which the sample temperature was compared. Based on the distribution of the maximum temperature differential and the sample heating rate, a self-heating probability value (SHPV) was calculated that corresponded to observed self-heating behavior. In this study, several of the carbonaceous shales and one coal waste had relatively high SHPV. The SHPV did not correspond directly to heating values or to differences in sulfur concentration.

Jan 1, 2010

By J. R. Thoenen

In June 1929 the Bureau of Mines issued a 13-page information circular entitled "Mineral Wool," which was one of the first publications to present to the public Rome technical aspects of the mineral-wool industry. Since then several articles on the subject have appeared in the technical press as well as in publications of State organizations. Inquiries for information on mineral wool have continued to be received by the Bureau of Mines in large number, and in 1935 it was decided to make a field survey of the plants then producing and to collect therefrom technical data to be compiled in a paper for nubile distribution. With the cooperation of the industry, this survey was made, and Information Circular 6984, Mineral Wool, was published in January 1930. The issue was exhausted after a few months, and requests for copies continued to come to the Bureau. As opportunity arose, further field studies were made in American as well as Canadian plants. The present circular contains the essential information in Information Circular 6994 together with date from later field studies.

Jan 1, 1939

By Bernadette C. Michalski

Mineral raw materials, labor, capital, and technology form the basis of industrial production. The augmentation of one or all of the elements--labor, capital, and technology--will result in industrial growth. Thus, an increase in the labor force would increase output. A similar result would be achieved by expanding capital investment and supplying labor with more equipment. Finally, industrial growth can be achieved by introducing more productive methods and techniques born of technological advancement. The Soviet Union has employed these elements in many patterns to catapult from an agricultural to an industrial economy in four decades. The early history of the Soviet Union was marked by limited capital and borrowed technology, forcing the Soviets to concentrate on an abundant labor reserve to support the industrial program. The source of this reserve was the rural population. In [1928], 80 percent of the working population was employed in agriculture. This figure dropped to 43 percent by 1956, whereas industrial employment in the same period increased from 8 to 31 percent.3/

Jan 1, 1960

By Joseph H. White

In its investigations looking to the improvement of health condi- tions and the increase of efficiency in the mining industry, the Bureau of Mines, in cooperation with the Bureau of Public Health, is studying sanitary conditions in and about mines with the intent of pointing out how those conditions that are a menace to the health of the miner may be most efficiently removed or remedied. An out- line of sanitary betterment work at mining villages in the Birming- ham district of Alabama has already been published by the bureau," and in this bulletin are presented suggestions on the planning of mining towns and the construction of miners' houses. The bulletin does not pretend to be a treatise on the so-called "housing problem," and mentions sociologic issues only incidentally. It is assumed that the influence of proper shelter on health is understood and that not a lack of appreciation so much as a lack of knowledge of the best remedies is responsible for many of the undesirable conditions that exist at mining towns. The purpose of this bulletin is to supply facts on the building of well-lighted, well- ventilated, warm, attractive, and economical houses for miners, these houses being assumed to be units of an industrial village or town the building and management of which are under the control of a corporation, so that special conditions hold which do not apply to houses built and owned by individual miners. From this it is not to be inferred that the company-controlled town is the best system or the only one in vogue. The discussion of this side of the subject in all its phases is too involved to be included in this paper. One element in favor of the company-controlled town is its possible immediate responsiveness. Hence this assumption. Also the assumption is made that a-new isolated town is being built, and hence the selection of the site, the arrangement of the streets, and the situation of the houses are discussed before the house itself is treated, for one of the most important factors in obtaining an economical sanitary house is a well-selected town site. Many of the suggestions, however, may be applied in improving conditions in existing towns, in building new houses in old towns, or in repairing old houses. Emphasis must be laid on the fact that as a rule a mining village has a shorter life than a manufacturing town. Economy is emphasized frequently because the discussion is predi- cated upon the assumption that the miner himself is to pay for all that he gets. House rent will doubtless be expected to bring in a reasonable return on all money invested in streets, sidewalks, water supply, sewer system, and houses; in other words, the town is to be run on a business and not on a paternal or charitable basis. "Fair and reasonable" precludes, of course, the idea of excessive returns. Some companies do not consider it good policy to realize as high a rate of interest as an independent realty company would be war- ranted in realizing. Under some circumstances part of the town improvements might be charged as "expense of the industry," that is, to the consumer. The isolation of a mining town introduces a unique responsibility. As the miners are practically obliged to rent the company houses, the officials of the company ought to scrutinize all expenditures in- volved so that house rent may be reduced to a minimum. In a way the town builders are placed in the position of trustees. They deter- mine, within certain limits, what proportion of a man's wages shall be spent on house rent. This consideration should restrain fanciful and unnecessarily expensive building; the other extreme should like- wise be avoided. True economy should be distinguished from cheap- ness. Ugly, insanitary, uncomfortable shacks should not be built even if, because of their cheapness, there is a demand for them from tenants. The obligation of the industry to society as a whole as well us to the tenant ought to forbid this. A cheerful, strong, healthy, virile race will not rise out of the filth and squalor of cheap hovels. An insanitary environment often does its damage slowly and silently; vitiated air does not, like mine gas, announce its deadly work by an explosion. As Talbot⚫ says: Health depends in part on freedom from infection. The probability of obtain- ing that freedom will be greatly increased by maintaining the body at a high state of vigor, or "vitality," as it is popularly called. This implies the promo- tion of all agencies which have to do with the physical well-being as well as with the control of sources of infection. Many men realize that in building houses for their workmen they are invested with a peculiar responsibility that must be wielded wisely, and in large developments they call into consultation the land- scape architect, the sanitary engineer, and the building architect, as well as the mining engineer.

Jan 1, 1914

By James P. May

Operating mine haulage trucks near the crest of stockpiles and waste dumps is a potentially hazardous practice often resulting in a localized slope failure and a dump point accident. The U.S. Bureau of Mines has developed a computer code (INSLOPE3) based on the kinematic method of limit analysis which determines an admissible truck weight (upper bound value) for varying distances from the slope edge. The program considers the material strength parameters, slope geometry, and inertial forces induced by vehicle braking. The program can be utilized to assist in the determination of safe operating distances for a haulage truck from a slope edge, the development of safe vehicle operating procedures, and the admissible weight for a static concentrated loading near the crest of an otherwise stable slope. This report provides information on the use of INSLOPE3, interpretation of the results for mining applications, and instructions for acquiring a copy of the software.

Jan 1, 1991

By Gary P. Sames

The Bureau of Mines recently initiated a study of geologic features that contribute to roof instability in western U.S. underground coal mines. The purpose of the study is to provide information for use in ground control planning and safety hazard reduction in that region, where mining activity has been increasing. Hazardous geologic conditions were surveyed in selected underground coal mines in Utah and Colorado, and both depositional and structural features were identified as potential ground hazards. Although the conditions found do not differ in kind from hazardous geologic conditions in the Eastern United States, they do differ in intensity of occurrence and relative importance. Three depositional features dominate where unstable roof occurs in western underground coal mines: paleochannel deposits, crevasse splay deposits, and flood basin deposits. Three structural features identified as hazardous, but not so widespread or common as the depositional hazards, are faulting, jointing, and igneous intrusions. This survey establishes a foundation for future studies aimed at reducing and preventing ground control accidents in western coal mines.

Jan 1, 1988