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By John J. Moore

This paper discusses the application of a video technique to construct stability diagrams for the combustion synthesis of ceramic-metal composites. Several model exothermic combustion synthesis reactions have been used to investigate the effect of the reaction parameters, eg. stoichiometry, green density, etc, on the stability of the propagating combustion reaction front and subsequent product morphology. The effect of varying the reactants and their stoichiometry to provide a range of reactant and product species ie. solids, liquids and gases, in the synthesis of both dense and expanded (foamed) ceramic and ceramic-metal composites was also investigated with respect to their corresponding combustion front stabilities.

Jan 1, 1993

By Heinrich Ries

Fullers' earth is a clay-like substance, which has the property of decolorizing or clarifying oils. An ultimate chemical analysis shows it to differ from most ordinary clays in having usually a high percentage of combined water and a low amount of alumina. There is probably a large amount of hydrous silica present. Fullers' earth possesses little or no plasticity, and in order to work properly has to be ground very fine. A chemical analysis is of little value at present in determining its quality; only a practical test suffices. Up to about two years ago all of the fullers' earth used in this country was imported from England; but about that time deposits were discovered in Florida, "† and since then rumors of its occurrence have been coming from all parts of the country. Next to the Florida deposits of fullers' earth, those of South Dakota are the most extensive thus far discovered in this country. The earth was first discovered near Fairburn, Custer county, and other deposits have since been prospected at Argyle, Minnekahta and other localities. Fairburn.—One of the first deposits located and opened up is five miles southeast of Fairburn, Custer county. The mine is a mile from the Fremont, Elkhorn and Missouri Valley Railroad, and the section exposed shows, beginning at the top: Feet. Micaceous sandy clay,......... 6 Fullers' earth,..........9 Micaceous sandstone,......... The fullers' earth passes upwards into the sandy clay, but in its purer portions it is a yellowish, gritty clay, with a somewhat

Jan 1, 1898

By WenCai Li, Yong Ren, Shuai Niu, Xin Hong

"Temperature measurement is very important in metal smelting process. Many devices are used to realize non-contact temperature measurements. Compared to conventional thermocouple, infrared temperature measurement has it's unique advantages. However, using an infrared temperature measurement at the top of the furnace can not obtain the desired optical signal because of disturbance from slag layer, high-temperature gases and other effects. A real time thermometry system with dual-wavelength radiation was presented to get optical signal emitted from molten metal through bottom-blowing nozzle. Taking into account the advantages and disadvantages of bottom-blowing devices, a MHP (Multiple Hole Plug) bottom-blowing device was used, through which the optical signal was transferred to the infrared thermometer by use of optical fiber. After conversion and analysis in real-time, the result was displayed and recorded in computer. After calibration, it could be a good predictor of temperature trend in a metallurgical process. IntroductionAt the refining stage of steelmaking, in order to achieve predetermined chemical composition and temperature, high-temperature molten steel is refined in a furnace such as converter. Because the refining process involved with chemical components and reaction velocities in the furnace rely on the temperature of steel, it is necessary to know the temperature accurately in real time during the process. And temperature measurement is also helpful for the end-point judgment. The temperature in the refining process changes quickly, for instance, in a converter, 300t molten steel is processed in only about half an hour.At present, traditional way of temperature measurement is using a thermocouple probe mounted on a lifter called a sub-lance. The thermocouple is immersed in molten steel and its temperature is measured during the short period until the thermocouple is fused. Accurate and reliable temperature can be obtained by this method, but in consideration of the discontinuous measurement and the costs, missing the end-point temperature may sometimes occur.According to the above background, a method in which a temperature-sensing element such as a thermocouple is immersed directly in molten steel is not suitable for the continuous temperature measurement because materials having such stability are not available. Therefore, radiation thermometry is promising. There have been some reports on radiation thermometry through an observation nozzle through the bottom or side of a refining furnace [1, 2]."

Jan 1, 2014

By D. Nutakor

This paper presents the results of a study conducted on a slope failure that occurred in the Q7 mining cut at Rio Tinto's Bingham Canyon Mine. The slope failure occurred in a weak rock mass with an estimated rock mass rating of 25%. The failure mechanism was of the circular type, involving ten 15-m (50-ft) benches and covered a total width of 152 m (500 ft). The analysis used Adam Technology's photogrammetric method with a two-dimensional rock fall simulation program (RocFall software) to design a 3-m- (1 0-ft-) high berm located 7 m (24 ft) from the toe of the failed mass. Back and predictive analyses were performed on a cross-section through the slide using Slope/W software, resulting in flattening the interramp angle (IRA) from 44° to 38°. This design modification produced a factor of safety (FOS) of 1.14. Sensitivity analysis involving FOS vs. pore water pressure showed that FOS is sensitive to water saturation. A dewatering system using a series of horizontal holes drilled below the slide and dewatering holes drilled from a drainage gallery has since been established to improve the stability of the slope. Throughout the one-year period since this investigation, no significant slope movement has been detected by the slope stability radar, and mining is in progress below the failure.

Jan 1, 2012

By Keith A. Heasley

At this point in time, approximately 800 M tonnes (880 M tons) of coal are mined each year in the United States. Forty percent of this coal or approximately 320 M tonnes (350 M tons) is taken from underground coal mines, and from this subtotal 16% or 50 M tonnes (55 M tons) is from longwall panels (1). If, for the sake of argument, an aver- age extraction thickness of 1.5 m (5 ft), an aver- age extraction ratio of 50 percent and an in situ density of 1360 kg/ms (85 lb/ft3) for this coal are assumed, then the 320 M tonnes (350 M tons) of underground coal translates to over 310 km2 (76,000 acres) that is undermined each year. Con- sidering that the total U.S. production of under- ground longwall coal to date is approximately 345 M tonnes (380 M tons), then a total of approximately 165 km2 (41,000 acres) (considering 100% extraction) has been directly undermined by longwall coal production in the United States. If the angle-of- draw is considered, the total area affected by longwall subsidence in the United States is probably twice the above value or 330 km2 (82,000 acres) . In the future, a number of other miscellaneous factors seem likely to multiply the number of potentially damaging situations that occur due to longwall coal mining. First, the overall production of coal in the United States is expected to gradually increase. This factor is further com- pounded by both the fact that the percentage of the overall production due to underground mining is bound to increase, since the vast majority of U.S. reserves (68%) are only recoverable by underground methods, and the fact that the percentage of the underground production of coal that is recovered by longwall mining is drastically increasing (1). Finally, as the nicest underground reserves are depleted, the remaining reserves will tend to be deeper, which increases the affected surface area, and under denser population concentrations, which increases the likelihood and severity of possible damages. Overall, considering the number of factor which are biased towards increasing the amount of undermined acreage, it appears that there must certainly be a corresponding increase in the number of possible damaging situations due to longwall-induced, ground subsidence.

Jan 1, 1986

By Walter Loel

THE application of aerial photographs to all phases of geologic mapping is set forth, indicating the advantages to be gained in different types of country and under varying climatic conditions. Methods of field and office procedure are given from a geological point of view, as well as suggestions regarding the best methods of aerial mapping for different uses and under varying field conditions, including the study of submarine geology. Aerial photographs with accompanying geologic maps are shown to illustrate the appearance from the air of different geologic features under varying climatic and topographic conditions.

Jan 1, 1938

By C. R. Tang

Due to the current lack of sufficient occupational hazards supervisory staff in China, an occupational hazards supervision regulatory framework is proposed, based on the cloud. Data on respirable dust, noise, heat, toxic and hazardous substances and protection facilities are uploaded to private cloud computing data and service centers to build an occupational hazards supervision system. This system promotes occupational hazards governance. Complex reports are generated. Through the establishment of an occupational hazard supervision data threshold, the dynamic regulation of occupational hazards is accomplished. The main characteristics of this approach are low cost, ease of expansion and maintenance, and strong performance.

Aug 1, 2013

By L. St-Georges

In aerospace and transportation industries, severe problems are related to fatigue failure. Aluminium is frequently used in these industries to optimize the solidity and minimise the weight of the structures. Nevertheless, the fatigue life of aluminium alloys is limited and specific efforts have to be made to reduce the vibratory stresses in the mechanical parts. When riveted, the life of the sheet metal structures can be increased compared to welded structures, due to the energy dissipated by the friction between the rivets and the sheet metal and the sheets themselves. In the past decade, a new tool was developed to assemble aluminium structures; the friction stir welding. With this new technique, fatigue life of the aluminium welded joints can be increased by a factor from two to ten. However, less energy can be damped by the friction between the components and increased vibratory stresses may occur. In this investigation, the potential of the friction stir welding to create damped aluminium sheet metal structures is evaluated.

Jan 1, 2006

By S. J. Aresco

The Bureau of Mines has been active in promoting the purchase of coal for Government use under specifications that define the requirements in terms of heating value of the coal, expressed in British thermal units, and the composition as shown by proximate analyses. To these, when required, are added the ash-softening temperature, the free-swelling index, and the Hardgrove grindability index. Under most of these specification contracts the bidders guarantee the quality of the coal, and that guaranteed by the successful bidder becomes the standard of his contract. The deliveries are sampled in accordance with instructions4 issued by the Bureau of Mines; the samples are analyzed in the Bureau laboratory to determine whether the coal is of the quality guaranteed by the contractor; if it is not, a price adjustment is made. Analyses of the delivered coal and tipple samples (samples collected at mine tipples as coal is being loaded into railroad cars or trucks) provide valuable data for use in evaluating future bids. In addition, the continuous sampling of coal as delivered is a check on the practical results obtained in burning the coal.

Jan 1, 1966

By R. R. Wells

As a part of the strategic mineral program, examining engineers of the Bureau of Mines collected samples several manganese properties in Colorado. As all of the ores were too low-grade to be acceptable to manufacturers of ferromanganese, beneficiation studies were required .to determine the amenability of the ores to concentration. Manganese in the form of impregnations in sedimentary beds is found in the Denver plains area a few miles east of the Rocky Mountain front. Deposits are reported to occur intermittently over a distance of more than 200 miles. The manganese oxides occur in beds of conglomerate or arkosic sand, generally accompanied by limonite. The Manganese and iron oxides,, however, usually are found in separate layers. Three samples were submitted for beneficiation tests, two samples from Buckley Field bombing Yang, Arapahoe County, and one from near Franktown, Douglas County.

Jan 1, 1952

By Steve Kral

The mining industry has waited a long time for the resurgence in commodity prices and demand for its products that it is now experiencing. Base and precious metals prices have reached levels not seen before. Coal prices have also shot up. And there are encouraging signs in the uranium market. China’s nearly out-of-control economic growth is said to be the leading driver for much of this resurgence. But demand for energy, metals and building materials in the United States and elsewhere are also major factors. The result is that expansions and new mines for nearly every commodity are in the works.

Jan 1, 2005

By W Mahoney, F Clement, E Saraiva

Prefabricated waterproofing sheet membranes are extremely complicated to install in underground sections with complex geometries and, despite being already subjected to quality tests in the factory, the installed membrane often exhibits leakages due to different reasons. Main sources of leaks are the required high amount of welding seams and damages caused during installation of reinforcement, as well as overstretching and poorly installed secondary concrete linings. Also the design of the tunnel lining is strongly influenced and limited by the use of prefabricated waterproofing sheet membranes. The use of sprayed waterproofing membranes for more than a decade has contributed to durability and serviceability, as well as to increasing sustainability of tunnel linings. The presented sprayed waterproofing membrane MasterSeal 345 is an advantageous alternative to prefabricated waterproofing sheet membranes under typical tunnelling conditions, especially in geometrically complex areas, such as in lay-by niches, cross passages and crossover caverns, where installation of conventional waterproofing membranes is inherently difficult, and locating leaks is challenging. This membrane has been successfully used in underground projects with different waterproofing design concepts and under diverse hydro-geological and environmental conditions for over a decade. It provides tunnel designers with different options and optimisation for the design of the tunnel concrete lining. Additional advantages to owners, contractors and designers from the use of the sprayed membrane include flexibility in the design, increased productivity and flexibility in working programming, as well as improved logistics, resulting in significant program and cost savings and reduced long-term maintenance costs. This paper describes the key features of this sprayed waterproofing membrane, its application range and limitations, the waterproofing concept, design options and related benefits. Further, guidance for membrane application and quality control and a summary of two recent project references in the United Kingdom and in Switzerland are provided.CITATION:Saraiva, E, Clement, F and Mahoney, W, 2014. The use of sprayable waterproofing membranes in underground structures – concept, design options, benefits and limitations, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 323–332 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By David E. Siskind

The Bureau of Mines has studied the fracturing and associated damage occurring in the vicinity of blastholes from five shots fired in the shale pillars in the White Pine copper mine, White Pine, Mich. Four types of explosives (AN-FO, commercial extra dynamite, ammonia gelatin dynamite, and a low-density, low-velocity permissible) were used. Cores were taken from the blast region and examined by ultrasonic and petrographic techniques. Pulse wave velocities were measured across the core diameters, and thin sections showing cracks and changes in lithology were examined in an attempt to establish zones of damage. Cores from the blast regions and areas near pillar free faces were found to have abnormally low pulse velocities. Petrographic study of the thin sections showed that the negative velocity anomalies were caused by cracks in the cores. Crushing and extensive fracturing prevented meaningful measurements on core fragments from the immediate blast vicinities. Compositional, changes and other rock nonuniformities, such as joints and preexisting fractures, tended to mask detailed damage differences among the four explosives; however, the two most energetic explosives (extra dynamite and ammonia gelatin dynamite) produced damage zones two to three times as large as the AN-FO and low-velocity permissible explosives.

Jan 1, 1973

By Frank G. Breyer

C ONDITIONS have not been favorable for new developments in any line. It has been a period, how- ever in which recent developments have been subjected to the severest tests. Those which have been able to hold their own in the severe competition of 1932 must be considered fully proved commercial processes. The continuous vertical-muffle retort plant at Palmer- ton is reported to have been in operation at practically full capacity throughout the year. The high quality of metal produced and the low operating costs are factors which have kept this plant running when many of the older furnaces were shut down. The plant at Meadow- brook, W. Va., is also reported to have been in steady operation throughout the year. Average retort life is said to be better than two years with about three-quarters of the original retorts still in operation after 2 ½ years.

Jan 1, 1933

By W C. Shakespeare

The Ontario Committee on Taxation is making a comprehensive study of taxation in the Province of Ontario, and in this connection has received representations concerning mining taxation from a number of interested parties. Some of the more important recommendations on mining taxation are reviewed in this article. Introduction FOLLOWING the appointment of the Federal Royal Commission on Taxation, the Ontario Government, effective in November, 1962, appointed the Ontario Committee on Taxation to review taxes and revenues available to the Province of Ontario and its local governments, to co-operate with the Royal Commission on Taxation and with any other bodies of enquiry appointed by other provincial governments, and to make such recommendations as it sees fit to the Prime Minister of Ontario and the Executive Council. The members of the Committee are: MR. L. J. SMITH, F.C.A., Toronto, (Chairman) MR. ERIC HARDY, Toronto DR. R. CRAIG MCIVOR, F.R.S.C., Hamilton MR. CARL A. POLLOCK, Kitchener MR. R. BREDIN STAPELLS, Q.C., and Toronto. Like its Federal counterpart, the Royal Commission on Taxation, the Ontario Committee has held public hearings, has received written

Jan 1, 1965

By Ayumi Yoshioka

Os componentes automotivos em geral devem atender a especificações rigorosas de propriedades mecânicas, requisitos de limpeza inclusionária, entre outros. Enxofre e alumínio são dois elementos adicionados ao banho líquido, que têm papel importante na obtenção destas propriedades, mas que dificultam o processo de produção por lingotamento contínuo por favorecer a formação de partículas sólidas de alto ponto de fusão, que podem prejudicar a limpeza inclusionária e provocar a obstrução das válvulas de lingotamento. O objetivo do presente trabalho é analisar e classificar as inclusões de corridas do aço DIN 38MnSiVS6 em escala industrial e avaliar estes resultados em conjunto com os dados de processo de aciaria e com os resultados de simulação termodinâmica utilizando o software FactSage 6.4. Foi observado que as corridas apresentaram tanto sulfetos de cálcio quanto espinélios, mas as primeiras, associadas a uma fração líquida menor na escória, tiveram uma correlação mais perceptível com a má lingotabilidade.

Aug 17, 2017

By M. Dupuis

Recently, a new approach to controlling alumina feeding in a H.H. cell has been proposed [1, 2 and 3]. This approach, labeled In Situ aluminium cell control, is based on a correlation between the slope of the cell voltage during a no feed observation period and the dissolved alumina concentration in the bath. Once the dissolved alumina concentration has been estimated, a primary calibration surface uniquely relating the dissolved alumina concentration and the anode-cathode-distance (ACD) to the cell voltage is used to estimate the cell ACD. Once both the alumina concentration and the ACD have been estimated at the end of the observation period, a PID controller can be used to regulate the rate of alumina feeding using only the normalized cell voltage to calculate the error between the estimated dissolved alumina concentration and a target value. The In Situ aluminium cell control algorithm has now been tested with the Dyna/Marc [4, 5 and 6] cell simulator demonstrating that it should be possible to control a H.H. cell in this manner with less variation in the dissolved alumina concentration and other process variables producing a prediction of improved cell current efficiency and power efficiency.

Jan 1, 2011

By Matthew S. Sanchez, Richard J. Lee, Matthew D. Zock, Drew R. Van Orden

"Current Environmental Protection Agency (EPA) risk models and asbestos fiber counting techniques for monitoring airborne exposures treat all fibers as being equivalent and ignore the effect of dimension on toxicity. While this may have been appropriate when modern analytical methods were not available, the measurement world is now fully capable of making the appropriate distinctions. The importance of width as a determinant of carcinogenicity has been recognized for nearly 30 years within the published literature. Stanton,1 in a landmark study of a suite of fibrous materials, found that durable mineral fibers with widths less than 0.25 mm and lengths longer than 8 mm were causally associated with the induction of tumors. Pott,2 in a later study, postulated a fiber toxicity model that agreed reasonably well with the Stanton findings, but extended the concept to include varying toxicity as a function of length and width. Wylie et al.3 reanalyzed samples used by Davis et al.4 and found that tumor generation was strongly and inversely correlated with fiber width. Crump5 testified increasing fiber length was correlated with disease occurrence. Lippman6 reviewed a number of studies and suggested that mesothelioma was closely associated with long, thin fibers. Berman et al.7 published a risk model, which found that disease was correlated almost exclusively with fibers longer than 40 mm and width less than 0.25 mm. Recently, Loomis et al.8 reanalyzed textile mill samples and found that aspect ratios greater than 40:1 were highly correlated with disease. Incorporation of width into risk models has been limited by the availability of data from operating asbestos plants and, in particular, the observation of an asbestos plant for which there is no observable mesothelioma. There have been only limited studies published on the dimensions of asbestos fibers, with a few serving as the primary references in other literature.9_13 A rare opportunity to collect detailed concentration and dimensional data of airborne crocidolite from an operating asbestos-cement plant using modern analytical procedures arose, providing a chance to supplement the existing literature on airborne fiber dimensions. The asbestos-cement plant is located in the eastern end of Cochabamba, Bolivia along Highway 4. Cochabamba is a relatively large city located in the Andes Mountains, approximately 250 km southeast of the capital La Paz. The city sits in a valley that runs east-west with mountains to the north and south. The crocidolite used in the products made at this facility is mined in central Bolivia, approximately 75 km northwest of Santa Cruz. The crocidolite is a fibrous magnesioriebeckite 14 (blue asbestos). Crocidolite fibers from Bolivia were the subject of prior reports suggesting the fibers are generally longer and thicker than crocidolite from Australia or South Africa.9 At the cement plant, the run-of-mine crocidolite was first pulverized using a hammer mill and then sieved on vibratory sieves to produce fibers of limited size ranges for use in the cement. The sieved crocidolite is mixed with other components, including recycled cement product, to produce a slurry that is vacuum filtered into sheet form. The sheets are then manually molded into a corrugated shape, air dried, and sawed (using circular saws) to accepted dimensions. The sawed sheets are cured in soaking pits for 28 days before being shipped to the consumer. Prior to shipping, the sheets are finished by a light hand sanding followed (at customer request) by applying one or more coats of paint. A detailed description of the cement plant and the industrial hygiene results can be found in Van Orden et al.15"

Jan 1, 2012

By A. T. Yu

There are compelling reasons for us to look to our Country's Western coal. Despite its inherent low BTU content, Western coal's low sulphur content provides a near-ideal answer to satisfy our in- dependent goals of clean air and self-sufficiency in energy. Vast reserves, thick seams and amenability to low-cost strip mining serve as a powerful economic basis for its viability as a primary and dependable source of energy for the coming decades. A major consideration, the solution of which may not be quite obvious, is transportation cost. These abundant deposits are remote from the utilities of the heavily populated eastern regions of the United States (Figure 1). A Western coal mine in Montana is likely 1500 miles or more from an eastern power plant. The comparable distance to an eastern coal mine may be only 200 miles. Thus, the question is: How can the haulage cost of our Western coal be substantially reduced to an acceptable level? If resolved, western reserves of coal will be one of the key solutions to satisfying our Nation's energy needs.

Jan 1, 1975

By M Breen

In 2009, George Fisher mine began to seriously consider the transition from pyrotechnic detonators to electronic detonators. Initially, the electronic detonators were used for complex crown shots or areas where ground conditions had the potential for excessive overbreak. After critically evaluating the potential safety benefits, production increases and ability to redesign stopes to better manage a thinly bedded hanging wall, the mine decided to embrace the technology.

Nov 8, 2011