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By V. A. Sernov

"One of the ways to increase the bearing capacity of a piled foundation is to take into account soil resistance in the base of the raft. Piled raft is similar to shallow foundation and can transfer significant part of the load into the base. It allows reducing number of piles in the foundation or shortening their length. As a result building terms and foundation costs reduce considerably. However, nowadays in Belarus there is no reliable and suitable in design practice methods of calculation of piled-raft foundations. In order to devise such methods we have analyzed the results of piled foundation tests fulfilled by various authors up to date and have carried out series of field and laboratory investigations in Minsk. The most important results of the investigations are provided in the article. Methods of analysis of piled-raft foundations are described.INTRODUCTIONPile foundations of late years are used extensively in connection with the increased number of storeys and load increment on the soil. Often pile foundations are applied in comparative favorable ground conditions at the surface of the base. In such cases the increase of the bearing capacity of foundations and the reduction of construction cost are questions of primary importance for designers. One of the ways to increase the bearing capacity of a piled foundation is to take into account soil resistance in the base of the raft. Piled raft is similar to shallow foundation and can transfer significant part of the load into the base. It allows reducing number of piles in the foundation or shortening their length. As a result, building terms and foundation costs are reduced considerably. However, nowadays there is no reliable and suitable in design practice methods of calculation pile foundations with bearing rafts. In order to devise such methods we have analyzed the results of piled foundation tests fulfilled by various authors up to date and have carried out series of laboratory and field investigations.Long before the constitution of the first piled-raft foundations in the Soviet Union there were attempts to consider soil resistance in the basis of isolated and strip grillages. Such bases can be considered as separate fragments of the piled-raft foundation. Prof. A. A. Bartolomey had tested more than 70 pile foundations of natural size in different ground conditions. The length of piles was 3 12 m (?????????? 1995). The observed results show that the raft carries about 10 12% of the total load applied when length of piles is over 9 m and space between piles is a=3d. Bearing capacity of the raft is about 35 40% when the length of piles is 5 8 m and a=6d. Prof. Golubkov has tested 2 prismatic piles (cross section: 350x350 mm, L=3800 m) and 2 pyramidal piles (cross section: head - 600x600 mm, foot – 100x100 mm, L=3000 m). One of the piles was tested with a raft and the other one without a raft. Significant influence of the raft on total bearing capacity was determined, the more the settlement was the more it influenced on the raft. Bearing capacity of the raft was 27,5% in foundation with prismatic pile and 42% with pyramidal pile (???????? et al. 1971)."

Jan 1, 2016

By Steven W. Schmauch

The Sugarloaf RARE II area (No. 5296) covers 11,100 acres in the northern part of the White Mountain Range, in the Inyo fictional Forrest. It is in Nevada, about 45 mi north of Bishop, California. A mineral survey was conducted by On U.S. burro of Mines in 1982 and by the U.S. Geological Survey in 1980-1982. The Bureau reviewed pertinent literature, searched Esmeralda and Mineral County mining records, obtained current claim information from the administrative agencies, and contacted claim owners. Thirty-six properties were examined, and 674 samples were taken from them to help assess win oral resources and potential. The Geological Survey evaluated the regional mineral potential by geologic, geochemical, and Geophysical surveys.

Jan 1, 1983

By Antoine Fournier, Karen St. Seymour

"Responding to market developments, interest in locating deposits of wollastonite has grown significantly. The many occurrences in the Grenville marbles of Quebec can be grouped into disseminated type and discordant vein-type deposits. Disseminated-type wollastonite occurrences have the disadvantages of lower grade, the need for more elaborate mineral separation, and failure to meet ""long grain"" technical specifications. Vein-type deposits have better grades and technical characteristics; exploration should be focussed on these and in the contact-metamorphic aureoles of fluid-rich intrusions. SOMMAIREEn réactions aux nouveaux de bouches, l'interet pour les gîtes de wollastonite a crû de façon marquée. Les nombreux indices sis dans la province de Grenville au Québec peuvent être regroupes en deux catégories soit: les indices dissémines et les indices en veines discordantes. Les indices dissémines ont le désavantage d'être moins enrichis, de requérir une séparation minéralogique plus complexe, et leur wollastonite ne possède pas le degré d'acicularité voulu. Les indices en veines sont plus enrichis en plus de rencontrer les critêres techniques; les efforts d'exploration devraient se porter vers ce type de gites et aussi, sur les auréoles métamorphiques de contact d’intrusions riches en fluides."

Jan 1, 1992

By Andrea Koschinsky

Ferromanganese crusts have traditionally been considered a potential ore for Co, whereas ferromanganese nodules have typically been considered a potential ore for Ni and Cu. However, both nodules and crusts sequester high concentrations of many metals (Table 1) from sediment pore waters and seawater, many of which are essential for high-tech applications. The resource potential of these rare and valuable metals is poorly known and they are the subject of considerable current research. The need for adequate and dependable supplies of these metals is essential for the development of new technologies. The rare-earth elements have recently received much attention in the scientific and popular press because of their use in so many high-tech applications and because more than 95% of the production comes from China (e.g., Service 2010); consequently, there is concern about the possibility of a significant decrease or even curtailment in exports from China. The lack of a primary source and the inadequate supply of Te have prohibited the development of a Cd-Te photovoltaic solar-cell industry (Hein et al. 2010). Inadequate supplies of many of the elements listed in Table 1 are limiting the development of key high-tech industries, forcing the use of alternative metals that [ ] may result in less efficiency or less favorable properties for a product. The rare-earth elements, Te, and other elements listed in Table 1 occur in high abundances in marine hydrogenetic and diagenetic ferromanganese deposits. Here, we look at the mechanisms by which these rare and valuable metals are incorporated into different genetic types of marine ferromanganese deposits.

Jan 1, 2010

By John R. Bitler

The Bureau of Mines conducted this study to provide information concerning the availability of and the demand for construction-mineral aggregates in the Baltimore, Md., Standard Metropolitan Statistical Area (SMSA). The demand is discussed with reference to the area's current consumption and estimates of the area's demand for aggregates through 1990. Estimates of aggregate supply are presented in conjunction with an examination of the geology of the area, the availability of substitutes, and the effect of transportation costs. A discussion of the constraints affecting aggregate availability precedes the conclusions and recommendations. The availability of aggregates is subject to geologic, economic, and political constraints. As of January 1974, an estimated 20,100 million tons of stone was available to meet the demand projected through 1990 (188.7 million tons). An estimated 139 million tons of sand and gravel was available to meet the demand projected through 1990 (84.3 million tons). Several alternative actions are available within the area to insure the adequacy of the stone supply and to increase the supply of sand and gravel: (1) The establishment of special mineral resource zones; (2) the application of sequential land use techniques; and (3) the exploration of previously undeveloped regions.

Jan 1, 1975

By P. J. Urso

"This paper discusses the mining problems encountered at the Fording River coal mine to date, and how they have been solved. All of the production now comes from surface mining, but underground hydraulic mining is planned and briefly described. Other facets of the operation, including markets, equipment and personnel, are covered. IntroductionFording Coal Limited was formed in 1968 to mine and market metallurgical coal resources held by the company in the East Kootenay region of southeastern British Columbia. The company, at its Fording River operations, holds approximately 48,000 acres of coal lands, having an estimated 2.0 to 3.0 billion long tons of metallurgical coal in place. (Although not a point for further discuss ion in this paper, the company also holds approximately 1.0 million acres of mineral rights. These consist primarily of coal in Alberta, potash and coal in Saskatchewan, and minor industrial mineral holdings of limestone, salt and bentonite in the three western provinces.)Fording Coal is owned 60% by Canadian Pacific Investments Ltd. and 40% by Cominco Ltd. Inasmuch as Cominco itself is owned approximately 54% by CPI, it is seen that the effective CPI ownership of Fording is about 82%. The company, originally staffed and managed by Cominco, has been independent since January, 1978, with its own board of directors, management, staff and employees.The company's head office is in Calgary, Alberta. The Fording River operations are located approximately 45 miles north of the Crowsnest Pass, near the Alberta/British Columbia boundary, only 95 air miles and 200 road miles from Calgary.A contract was signed in 1969 with the Japanese steel mills to provide 45 million long tons of metallurgical coal over IS years, commencing in 1972 at an annual rate of 3 million long tons per year. Despite some start- up difficulties, the mine and plant facilities achieved their rated capacities in 1975, producing and shipping at the 3-million-Iong-ton level. The coal specifications are shown in Table I."

Jan 1, 1980

By J. W. Rutter, K. T. Aust

The temperature dependence of the rate of grain boundary migration was measured in bicrystals of zone-refined lead containing from 20 to less than 1 ppm by wezght of tin. The apparent activation energy in the temperature range from 320" to 200oC is markedly dependent upon the solute tin concentration and upon the orientation relationship of the grains adjacent to the grain boundavy. The quantitative experimental observat~ons are compared with the predictions of various theories of grain boundary migration. In previous work.&apos;?&apos; the mobility of individual grain boundaries was studied as a function of impurity concentration and type of boundary. Grain boundary migration occurred at the expense of dislocation arrays which were introduced into the specimen during solidification. Boundary mobility in zone-refined lead at 300°C was markedly decreased by small additions of tin. 0.004 wt pct being sufficient to decrease the rate of grain boundary migration by a factor of 1000. The mobility of grain boundaries having polar orientation relationships near 38 and 22 deg about <Ill>, and 28 deg about <100>, was much less sensitive to tin concentration in the range studied. As a result, these boundaries have relatively high mobilities. The present paper is a continuation of the above study. Data are now presented on the temperature dependence of the motion of individual grain boundaries in zone-refined lead as a function of solute tin concentration and orientation relationship of adjacent grains at the grain boundary. The experimental observations are compared with the predictions of a number of theories of grain boundary migration3-8 which, prior to the present experimental investigation, could not be critically evaluated. EXPERIMENTAL PROCEDURE The striation or lineage structure of melt-grown single crystals of zone-refined lead, containing various additions of tin, was utilized to provide a driving force for grain boundary migration, as previously described.1,2 Each grain boundary under study separated the striated single crystal from another grain which was introduced by localized plastic deformation and recrystallization of a small region of the sample. The speed of migration of grain boundaries in dilute alloys of tin in zone-refined lead was investigated as a function of 1) tin concentration from < 0.0001 to 0.002 wt pct, 2) temperature in the range of 200" to 320°C, and 3) orientation relationship of the adjacent grains at the grain boundary. The substructure driving energy available for grain boundary migration was estimated to be about 4000 ergs per cu cm, within a factor of two, from specimen to specimen.&apos; The specimen dimensions, and growth and alloying procedures for the preparation of striated single crystals of lead of known tin composition, were as described previously.&apos; Each bicrystal was carefully wrapped in aluminum foil, and annealed in a well-stirred salt bath consisting of 50 pct NaNO2 and 50 pct KNO3, for known periods of time at a series of constant temperatures (*2°C). The grain boundary positions, before and after each anneal, were determined by etching lightly in a solution of 5 pct nitric acid in methyl alcohol, in order to follow the motion of the boundary and determine its rate of migration. Thus, the rate of motion of the grain boundary in a single specimen was measured at various temperatures. The above procedure was carried out for each grain boundary in seventeen different bicrystal specimens.

Jan 1, 1960

By T. Ranki-Kilpinen

In the flash smelting technique, developed by Outokumpu Oyj, off-gases with dust load are directed into the heat recovery boiler (HRB). As the temperature decreases, metallic sulphates become thermodynamically stable. Sulphation of oxidic particles initiates. The release of heat causes an increase in particle temperatures, and soft sulphated particles can stick to the heat transfer surfaces. Dust accretion may form and cause operational problems. The objectives of the project are to study sulphation reaction mechanisms and kinetics of flue- dust particles under HRB conditions, and get more information for the flue-dust treatment possibilities. The sulphation behaviour of synthetic Cu2O particles (37-53 pm) was studied using a fluid-bed reactor of laboratory scale. The experimental parameters in the latest campaign were oxygen and sulphur dioxide contents of 2.5-10 vol-% 02 and 40-60 vol-% SO2 respectively and temperatures of 600-660°C. Samples were examined microscopically (SEM+EDS) and chemical analysis were conducted. The sulphation rate was found to have a maximum at the certain temperature, which was dependent on the gas SO2 content. Regardless of the level of SO2, a rise in oxygen content promoted sulphate formation.

Jan 1, 2002

By Glenn Tobin

The overarching goal in modern drill and blasting operations is that of optimising mining operations to achieve higher levels of productivity, safety, profitability and sustainability. Air decking, a technique used in drill & blasting to optimise explosive product use while achieving a target rock fragmentation1, is a technique that when executed correctly is proven to achieve consistent results independent of rock strength and the position of the holes (single, multiple, vertical, slanted), as well as being proven to reduce super-fragmentation (under-size or fines) while able to achieve optimal fragmentation, especially in the stemming zone2. The ‘shock absorber effect’ if the air deck reduces ground vibration and air blast3. Additionally, the practice of loading explosive product directly in saturated ground without dewatering or lining prior is an increasing global trend.

Jan 1, 2012

By F. Selig, E. J. Couch

The following points serve to supplement the interesting theoretical study on forward combustion by Thomas, and may be of some general interest. The mathematical model presented by the author can be viewed as a first approximation to the problem of calculating the vertical burned height profile resulting from ignition of the interval | z |<h/2 in a very thick formation. However, the assumption of a given minimum combustion temperature T, would give a better approximation to the vertical burned profile if the burning height were not constrained to stay within the ignited layer. This follows from the fact that both fuel and oxygen are present in the adjacent region, |z|>h/2, and for certain combinations of process variables the temperature is sufficiently high for complete combustion to occur. In this case, the vertical coverage will first become greater than the ignited interval before cutting back to zero as the extinction limit is approached as shown in Fig. 1. Such growth of vertical coverage is possible if the minimum combustion temperature is less than the initial source temperature (r = rj) at the edge (z = h/2) of the ignited interval. But this latter temperature is equal to one-half the source temperature for the case of infinite burned height.&apos;,&apos; Thus growth will occur initially if The fact that the vertical burned height can be greater than the ignited interval complicates the picture considerably, as can be seen by referring to Fig. 1. Here burning occurs in Region A, whereas none was possible in the original mathematical model. At the same time, there is no combustion in Region B, contrary to the assumption of burning in the entire layer |z|<h/2. This apparent inconsistency suggests that the vertical coverage derived from this simple model does not adequately represent the vertical height of the burned zone. A more compatible model will result from the actual stepwise calculation of the burning length (as a function of time) that would give rise to the specified combustion temperature. This problem can be more conveniently attacked by using the temperature distribution, given by the author&apos;s Eq. 12, expressed in the integrated form:

By J. E. Schaefer

A summary of oil and gas development in Ohio for 1936 is necessarily brief and, in some details incomplete, owing to the lack of a central state agency for the collection of data and statistics on well drilling and production. The information used in this report was compiled from the records of the several companies operating in the state. Drilling activity in Ohio increased during 1936 as compared to the two preceding years. During the year 1157 wells were completed, as compared to 1022 wells in 1935 and 1055 wells in 1934. However, in spite of this increase in drilling activity, both oil and gas production declined for the year. Activity by Fields Trenton Sand Field.—The Trenton sand field is located in 15 counties of northwestern Ohio, trending from Toledo on the north, south and west through Findlay into Indiana. About 40 years ago the Trenton field was one of the most important oil-producing fields in the United States, but it has declined to a position of minor importance. During the year 1936 there were 52 completions in this field—29 gas wells, 19 oil wells and 4 dry holes. Clinton Sand Field.—The Clinton sand is by far the most important gas-producing field in the state. Production is located in small pools separated by nonproducing areas, on a band of varying width reaching from Cleveland on the north to Lawrence County on the Ohio River on the south. During 1936 a small pool of patchy character was developed in Butler township, Knox County. Seventeen wells were completed in the Clinton sand, of which 13 were gas wells and 4 were dry holes. The average initial production secured per well drilled, including dry holes, was 1,288,000 cu. ft. The average depth of the Clinton sand was 3000 feet. A gas well was completed in lot 9 of Franklin township, Tuscarawas County. Production was found in the first Clinton sand at a depth of 4354 ft. The initial open flow after shot was 828,000 cu. ft. and the rock

Jan 1, 1937

By R Hindstr÷m

The demand for iron ore has increased dramatically in the last years and is forecast to remain on a stable high production level for years to come. ItÆs expected that the world economy is facing a stable continuous growth of iron ore to two billion tonnes and more over the next decades (Beddows, 2007). Furthermore it is expected that the existing and known high-grade ore resources will decline, and the iron ore industry will be forced to implement more and more advanced beneficiation plants. As a consequence of the more complex beneficiation requirements, there will be a need for modern solutions for iron ore dewatering that are reliable mechanically as well as cost effective and with high capacity per unit at the same time. Conventional vacuum filtration methods have been the most prevalent in fine iron ore dewatering. Product quality needs, lower ore grades, complex mineralogy and energy costs have resulted in iron ore producers seeking better solutions for dewatering, in particular pelletising feed. New advanced filtration methods have been introduced to the market. This paper describes how these modern methods are answering the needs of the industry. Performance of advanced dewatering technologies (pressure filtration and ceramic capillary action filtration) for iron ore applications has been studied, and the findings are based on both industrial and pilot scale experiences on different materials. For example, the results show that the cake moisture content of iron ore pelletising feed can be optimised more effectively by using modern filtration technologies. By selecting the most suitable and adjustable equipment, the effects of variations of feed material on downstream processes can be minimised and the possibilities of processing more difficult raw materials to high-quality pellets are better. The Larox Corporation develops, designs and manufactures industrial filters and is a leading technology company in its field. Larox is a full service solution provider in filtration for separating solids from liquids. As such, this paper compares the new developments in this market area with the prevailing known vacuum filtration technology, but focuses on a comparison between capillary action filters and rotary vacuum disc filters (RVDF). The trade name CeramecG is used to differentiate the Larox filter from the generic term.

Jan 1, 2007

By AIME AIME

ORGANIZATION of The Federated American Engineering Societies was effected at the organizing conference of national, local, state and regional engineering and allied technical organizations at the Cosmos Club, Washington, D. C., June 3 and 4. Thus is brought into being the greatest national engineering society in the world. The object of the organization is to further the interests of the public through the use of technical knowledge and engineering experience, and to consider and act upon matters common to engineering and allied technical professions. Prominent engineers from all parts of the country, representing more than 75 engineering societies, with an aggregate membership of more than 125,000, participated in the organization. The constitution as adopted by the conference, calls for the creation of s managing body to be known as the American Engineering Council, and its executive board. The belief was expressed that the entire organization would come to be spoken of as the American Engineering Council. The council is to coordinate the activities of state councils and of local affiliations whenever these activities are of national or general importance or may affect the general interests of engineers. Representation in the council is to be according to membership of the component societies.

Jan 1, 1920

By R. A. Horn, S. M. Telfer

"Canada has a per capita GDP second only to Japan among the G7 countries and a positive trade balance which ranks third among the world&apos;s major economies. International trade represents a very large part of the national economy and as a proportion of GDP is larger than that of all the other G7 countries with the exception of Germany. On the negative side the Canadian current account deficit relative to the size of the economy is significantly worse than that of all major industrial countries, due mainly to the cost of servicing an immense foreign debt and to a large and worsening negative trade balance in manufacturing.The outflow of money may be reduced by increasing the productivity and competitiveness of those sectors of the economy in which Canada already has a leading competitive position and which have the potential for further growth. The mining industry is uniquely qualified in this respect in that Canada is the western world&apos;s largest producer of metals and mineral products and has the geology and the exploration skill to replenish reserves assuming that an adequate level of investment is maintained. In 1989 the minerals industry contributed $8 billion to the country&apos;s balance of payments and with the exception of forestry is the only sector of the economy which has shown consistently increasing foreign earnings over the long term.In recent years there has been a decline in exploration in Canada and a significant increase in countries such as Chile. The demand for hard currency to finance the development of the newly emerging capitalist economies of the CIS and Eastern Europe is also driving these countries to seek foreign investment to allow them to exploit their natural wealth more efficiently. Canada is therefore facing growing international competition for risk capital and in the future its trade surplus will probably decline in the face of lower cost foreign production.Canada rightly exercises a high level of environmental control on its mining operations; however a significant deterrent to investment is the fundamentally unjust application of the many provincial and federal environmental laws, under which a mining company, even if it takes every measure to protect the environment, runs the risk of eternal and unlimited future liability. If this situation is not rectified the effect will be an increase in global pollution as mines in countries with more lax application of law and regulations controlling environmental damage replace those of Canada. Tax benefits and incentives are a more efficient means than arbitrary regulations in minimizing environmental damage."

Jan 1, 1994

By C. H. Herty Jr, C. H.

FEW subjects have attracted the attention of metallurgists more than oxygen in steel. From the days of Mushet and Ledebui interest in this subject has been increasing, and as additional knowledge has become available, the problem has naturally grown more complex. Instead of using the simple term "oxygen" we now distinguish between iron oxide, silicates of various kinds, oxysulfides, oxygen as gas and oxygen in solid solution in steel. There are five general methods for determining oxides in steel: hydrogen reduction; vacuum fusion; various wet-extraction methods, including electrolytic methods; methods depending on volatilization of the iron away from the oxides; and metallographic methods. For oxygen in solid steel each of these methods has both advantages and disadvantages. The hydrogen-reduction method is of no use on steels above about 0.20 per cent. carbon; 1 furthermore, it gives only FeO and possibly some MnO. The vacuum-fusion method2 is expensive and gives total oxygen, with the exception of some A1203, and does not differentiate between the various oxides in which the oxygen exists. Most of the wet-extraction methods3 give only the more insoluble oxides SiO2 and A1203, though the iodine method gives MnO to an uncertain degree (information that may be more misleading then no information

Jan 1, 1957

By Kang-Hyun Lee, In-Mo Lee, Byung-Kyu Kim, Parkm Jinho, Seoung-Won Lee

"In this study, the TBM Resistivity Prediction (TRP) system is developed for predicting the location, thickness, permittivity ratio and electrical conductivity of anomalous zones ahead of tunnel face using the measured resistivity of the ground. The applicability of the developed system was verified by performing field tests at a construction site in which an EPB-shield TBM is used for tunnelling work. In the first field test, it was found that the rock around the tunnel face had the same resistivity and permittivity with the rock ahead of the tunnel face indicating no anomaly ahead of the tunnel face. In the second test, a stronger zone 5-m thick was predicted ahead of the tunnel face based on lower permittivity than that of the rock around the tunnel face. The ground condition assessed by the newly developed TRP system matched well with that either predicted from geophysical exploration or directly obtained from drilling boreholes or from daily observed muck conditions. INTRODUCTION During tunneling work, the emergence of unpredicted zones of relatively weaker or stronger ground can lead to delays in construction work or an increase of construction cost. Predicting anomalous zones ahead of tunnel face in advance can thus prevent time and economic loss. For these reasons, various methods to predict the ground condition ahead of the tunnel face have been studied and developed. Prediction methods using various kinds of equipment include tunnel seismic prediction, ground penetrating radar, electromagnetic surveys based on electronic antennas, and electrical resistivity surveys conducted by analyzing electric currents in the ground ahead of the tunnel face (Ryu et al. 2008). However, most of the prediction methods are only applicable to conventional tunneling job sites, which feature free access to the tunnel face. In mechanized tunneling projects, accessibility to the tunnel face is very limited because the tunnel face is occupied by the TBM."

Jan 1, 2016

A mining companyÆs approach to managing the risk of theft of explosives and initiating devices should be underpinned by an organisation-wide policy developed with internal and external consultation. It should be based on the principles of sound proactive risk management, planning, monitoring and remedial action. This paper aims to provide mining (and construction)organisations with the rationale and many of the tools they need to control explosive security risks. As with all legislative compliance, they are best managed by incorporating the statutory and legal requirements into company policies, management systems and plans, operating procedures and culture. This is the approach that has been adopted in this paper. Trends we should expect: more prescriptive legislation and stricter government regulations; enhanced enforcement and more prosecution; more sophisticated detection systems, eg airports; additional compliance costs; additional vigilance on record keeping; improved risk awareness and risk communication; wider use of explosives policies, management systems and plans; and additional security staff with investigative skills.It should be noted that mining companies will be required to play their part in reducing the likelihood of explosives, intended for mining purposes, being wrongfully used to threaten, hold to ransom or to injure individuals or members of the public or to produce property damage. This will be done by putting in place safeguards to reduce the risk of theft of explosives while they are under their control. On that basis, this is a business risk assessment rather than a hazard risk assessment. A conclusion of this paper is that mining companies can and should play their part in reducing the supply of explosive materials that can then be used for illegal activities. In fact, mining companies have always had this duty, but now the stakes are higher û æcomplacency no longerÆ.

Jan 1, 2004

By D. Harrington

My acquaintance with rock, dusting as a preventive of wide spread explosions in coal mines dates from the fall of 1914 and the spring, summer and fall of 19.1.5 when I had an opportunity to observe the staging (both before and after) of several of the explosions in the Experimental Mine at Pittsburgh and saw violent explosions stopped by rock dust, also saw violently explosive coal dust made insensitive by use of rock dust to ignition or to propagation or spreading of an explosion. From this work I became a convert to rock dusting though I had previously been a firm believer in watering methods and am yet a firm believer that watering, methods have a well defined place in promoting the health and safety of our coal miners. In 1916, while in the Bureau of Mines service, I made an underground study and a report to the Bureau on the first extensively rock dusted mine, in the United States, the Delagua Mine of the Victor American Fuel Company near Trinidad, Colorado, there being then some ten miles of entry in that mine which had been kept well rock-dusted for at&apos; least four years The dust used was " adobe" or surface soil screened from sweepings of the dry surface wagon roads through a screen with one-eighth inch openings, the dust giving about 20% through 200 mesh and about, 10% of approximately 1/8-inch size. The material was collected during dry weather by contract at $1.00 per ton (sacked) and was accumulated in summer and stored for winter and spring use. The dust was scattered through haulage entries by hand or by an electrically operated blower and was held on shelves along the ribs or between and on timber caps with from 1/4-inch to 2-inch thickness of the rock dust. The cost of maintaining the 10 miles of entry well dusted was about $1,500.00 per year or $150.00 per mile per year. Total cost of &apos;the rock dusting over a four-year period was about $6,000.00, about 2,500 tons of dust being used and 2,000,000 tons of coal produced; the above cost included about 1,200 days labor dusting at $2.50 per day, 2,500 tons of rock dust at $1.00. per ton and miscellaneous labor, material, repairs, power cost, etc., amounting to about $500.00. The cost per ton of coal produced for keeping 10 miles of entry rock dusted being about 3/10c. In addition to the rock dusting, some sprinkling was done, chiefly in the interior of the mine, costing about 2/5c per ton; and due to spilling of coal and sifting of coal .dust through loose cars on the entry floors, the floors of haulage roads were kept sprinkled between and just outside-the rails. Total cost of sprinkling and rock dusting was about .7/10c per ton much less of course than the same work would now cost. Between January, 1916, and July, 1924, my duties in the Bureau of Mines allowed me, to follow up and make underground inspections and reports on more than 20 coal mine explosions and fires in a number of states of the union and in this work a large number of samples of road, rib, and other dusts were taken to ascertain the effect of moisture, roof and floor dirt, etc., upon the propagation or the stopping of the explosion; also a large part of my work was to obtain evidence pro and con as to influences affecting the disasters and very prominent among those influences were the occurrence or use of water, water drippers, or ponds, as well as of sand, roof or floor rock or dust on floor, ribs, etc. The Dolomite explosion near Birmingham, Alabama, in November, 1922, and the Dawson No. 1 Mine Explosion at Dawson, New Mexico, in February, 1923 (at both of which I made underground inspection and report) both starting on main intake haulage road and both in mines which had fairly elaborate watering systems, convinced me that at least as far as freezing can occur on main intake air courses which also act 2s main .haulage ways, rock dusting is likely to be much more dependable than sprinkling. In making up the report on the Dawson Explosion to the Bureau of Mines (copy of which also

Jan 1, 1925

By Corale L. Brierley

Accumulations of microorganisms in the in-situ leaching environment are believed responsible for plugging of the orebody and thus decreasing uranium extraction. To assess the contribution of microbial growth to this problem, packed columns of ore and core specimens were leached in the laboratory. Samples collected at four in-situ uranium mining operations revealed pseudomonads, xanthomonads, Bacillus sp. and Micrococcus sp. in numbers of 105 cfu/ml. These microorganisms, inoculated into simulated leaching conditions, decreased permeability in two uranium ores by one order of magnitude in 20 days. Hydrogen peroxide (0.2 g/l) alleviated microbial plugging in the laboratory. Periodic injection of hydrogen peroxide through the production well into the orebody may reduce microbial plugging problems in the field.

Jan 1, 1982

By Justin Simmons, Michael Arnold, Bob Faulhaber

"In order to remodel an existing beach resort on the Gulf of Mexico, an existing three story structure, founded on stepped tapered piles, was to be replaced by a ten-story building with service rooms on a daylight basement level, conference rooms on the next levels and up-scale hotel rooms on the upper levels. The new building was founded on augered-cast-in-place (ACIP) piles. The pile caps and the basement required excavations between nine and fifteen feet (three to five meters) below ground surface.BAUER Foundations Corp. (BFC) successfully used Cutter Soil Mixing (CSM) to install the support of excavation walls. This technique allowed for the adjustment of the wall alignment during execution in order to avoid existing and new piles and other underground obstructions. Nearly 1600 – 16-inch (400 mm diameter) ACIP piles were installed to an average depth of 71.5 feet (22m) below ground surface (BGS) by BFC to support the new hotel structure. Initial grout overages in piles were excessively high and ground stability issues were encountered in some pile locations. By identifying specific areas of concern BFC was able to modify the approach to ACIP installation, effectively mitigating the ongoing risks and successfully completed the project.PROJECTMarriott Hotels began the $300 million renovation and upgrade of their Marco Island Marriott Beach Club Hotel in Marco Island, FL to JW Marriott status in May 2015. The renovation included the demolition of a portion of their existing hotel tower, and the construction of a new 10-story hotel tower consisting of 94 new guest rooms and a 10,000 SF (900 m2) ballroom, among other amenities. As is typical with hotel construction, time was of the essence. The schedule was the driving factor of this project as the owner had already booked events in their new ballroom starting in January of 2017.BFC provided the client with a deep foundation package that included the installation of 1562 Augered Cast-In-Place (ACIP) piles supporting the new tower, and the design and construction of approximately 36,500 SF (3,400 m2) of soil-mixed retaining wall for support of excavation (SoE)."

Jan 1, 2017