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By P. T. Bloomer

Introduction Mining of the orebody of the Sullivan mine, which is owned and operated by the Consolidated Mining & Smelting Company of Canada, Limited, has reached a point where pillar extraction is rapidly becoming a major part of the operation. Very few of the larger pillars have been completely extracted; consequently, this paper contains much that is theory and expectation. Due to early mining methods and the physical characteristics of the Sullivan deposit, similar conditions may not exist in other older mines facing the problems of pillar extraction, but it is thought that the methods employed and those contemplated may be of general interest. History The Sullivan orebody, which is at Kimberley in the Fort Steele mining division of the East Kootenay district of British Columbia, was discovered in May, 1892, by Messrs. Sullivan, Smith, Cleaver, and Burchett. After passing through the hands of several owners the property was optioned in 1909, and purchased in 1910, by The Consolidated Mining and Smelting Company of Canada, Limited. Early mining was highly selective, the objective being a clean, high-grade silver-lead ore. By 1923 the difficulties of milling the very complex ore had been overcome and the first unit of a concentrator was completed with a capacity of 2,500 tons daily. Capacity was increased by stages to the present rate of 8,500 tons per day. Concentrates are shipped over the Canadian Pacific railway ? to the Company smelter at Tadanac, British Columbia, for final treatment. Approximately 45,000,000 tons of ore has been mined to date.

Jan 1, 1948

By D. K. Fountain

"High metal prices and advanced technology in open-pit mining methods have resulted in considerable interest in the development of large, low-grade mineral deposits. Brenda Mines Limited is presently testing such a deposit of copper-molybdenum mineralization near Penticton, British Columbia.The mineralization of economic interest at Brenda has a total metallic sulphide content of between 1 and 1.5 per cent. This sulphide content approaches the limits of detectability of standard geophysical methods. How-ever, due to a favourable geological environment, it has been possible to utilize the Induced Polarization Method to outline the mineralization at the Brenda property."

Jan 1, 1968

By G. S. Barry

INVESTIGATIONS to date have shown that, should there be the need or the appropriate economic stimulus, Canada's mineral resources are sufficiently extensive to allow considerable expansion of its non-fuel mineral industry, during the remaining part of this century and possibly beyond (1, 2). The availability of sufficient capital will be one of the critical factors which will determine whether this potential will be fulfilled. The following analysis centers on the capital requirements of the Canadian non-fuel mineral industry under one set of basic assumptions of capacity growth, cost of new and replacement capacity, rates of depletion and depreciation of mines and plant, and the cost of exploration and infrastructure. Mindful of the fact that exploration and development will not thrive in Canada unless a very positive approach is taken, the writers make no apologies for being "optimistic" about long-term production prospects. Furthermore, in the event that world demand does escalate as anticipated and the forecast realistically attainable levels of Canadian production are not reached, then Canada will not have reaped the full range of economic benefits available, and opportunities will have been lost. Projections for Canadian production between 1976 and 2000 are essentially based on the forecast published in the 1974 paper, "Towards a Mineral Policy for Canada - Opportunities for Choice (3), with some updating on the basis of recent developments.

Jan 1, 1977

By T. Haubold, K. Ortner, T. Jung, D. Roth-Fagaraseanu, C. Mattern

Application of integrally bladed disks (blisks) is of increasing interest in compressors of aero engines. Blisks are preferred due to their potential for size and weight reduction, for increased performance and for reduced manufacturing costs compared to conventionally bladed disks. Erosion of the blisk aerofoils in service reduces engine performance, and can result in short shop visit cycles. This significantly increases the life cycle cost of these components, particular when considering that eroded aerofoils can't be exchanged easily for blisks during refurbishment. Shop visit cycle times can be extended and maintenance costs can be reduced through the application of an effective protective coating. The ongoing development of an erosion resistant coating and deposition process suitable for coating complex blisk geometries is described here. The coating is a multilayered W /TiB2 system exhibiting superior erosion resistance compared to known single- and other multilayer concepts. A modified sputter process is used to enable coating even of blisk geometries with shadowed surface to competitive recurring cost.

Jan 1, 2006

By G. De Gregoriis, G. E. da Mota, H. P. Dias, J. E. M. Blasques

In recent years, like many other smelters around the world, Albras has been increasing line current. The necessary adjustments to the work practices and process variables need to be made on all potlines, which in this case means on 960 cells at the same time. It was a challenging task to adjust the process parameters to the new amperage. In July 2003 potlines 2, 3 and 4 were running at 1 73 kA and the goal at that time was to reach 180 kA. Preliminary trials with 180 kA were performed on a group of 10 boosted cells on potline 3 in order to investigate possible operational problems. It was decided to increase the amperage in three steps accompanied by continual evaluation of the state of the process. In July 2004 the target of 180 kA was achieved with good operational results. This paper presents the overall results, the parameter adjustments made during the amperage increase in the booster group and how the increase was implemented on the other potlines.

Jan 1, 2006

By G. H. Gale, M. A. F. Fedikow, L. B. Dabek

Abstract-Rare earth element (REE) data are reported for ores, sulfide-bearing rocks and host rocks from massive sulfide deposits and barren sulfide facies iron formations in Proterozoic volcanic rocks of the Flin Flon-Snow Lake area, Manitoba. Some of the rare earth elements (e.g., Eu), are selectively leached in zones of intense alteration and redeposited together with the sulfides and silicates in the uppermost parts of the alteration zones and at the rock-water interface. Chondrite normalized REE profiles of layered sulfide ores and exhalites proximal to the deposits typically have positive europium anomalies and are enriched in light REE. In contrast, barren sulfide facies iron formations exhibit negative or ‘normal’ Eu profiles. REE data are useful to explorationists in determining the presence of ‘off-hole’ metal-bearing sulfide zones, in distinguishing metal-poor sulfidic layers related to ‘economic’ hydrothermal activity from barren sulfide facies iron formation and in some instances as a means of establishing ‘ore-equivalent’ strata.

Jan 1, 1997

By Corrie Pitzer

Safety performance in many companies and even industries has stalled in the last decade. Accidents rates are improving but more slowly and yet, serious accidents and fatality rates are not: in fact, these rates of more serious incidents have plateaued or deteriorating. In more dramatic cases, organizations that had ?exemplary? safety statistics, suddenly had a catastrophic or multi-fatality event occurring. Popular books such as In Search of Excellence of Peters and Waterman or Good to Great of Jim Collins created many delusional ?secrets? or recipes, to achieve great performance and yet, most of those ?great? or ?excellent? companies have now declined in their performance, some dramatically and some have fallen from grace, like Fanny Mae, a company Jim Collins identified as a ?great? one, that had to be bailed out in the latest financial crisis. These organizations share several ?delusions? about managing a business, and often, these delusions are created by academics, consultants and authors of popular books about (safety) management. More damaging however is that safety management is defined by a set of key practices or axioms: a focus on human error, compliance to rules and regulations, creating consistency of systems and actions, reacting to accidents and incidents and on prevention of those, measuring safety with performance metrics and rewarding employees on those measurements. All of these axioms contain the seeds of destruction, and they create conditions and dynamics that precede the disaster - and ironically, they are all 'good things' we do in safety management. For example, a mere focus on safety in the business, and the measurement of it, create a culture of repression of mistakes and incidents, leading to a situation where the organization knows incrementally less and less of risks and risktaking behaviour - until the day it all coincides destructively! This paper discusses seven such safety delusions and how they impact on the views and safety management approaches. They are: ??The delusion of (risk) control, that risks can actually be identified, analyzed and mitigated. ??The delusion of compliance, that mere compliance to rules will safeguard the business ??The delusion of consistency, that standard operating procedures will ensure safe operations ??The delusion of predictability, that accidents and trends tell us everything about the risks of the future ??The delusion of human error, that people are the weakest link and that it can actually be dealt with through discipline and enforcement. ??The delusion of statistical trends, that safety is measurable with statistics ??The delusion of invulnerability, that we have achieved high levels integrity and capability to deal wit risks. Organizations that suffered catastrophes all share some or all of these delusions and this paper traces how these played a role in many disasters, ranging from the Titanic, Challenger, Piper Alpha, Bhopal, BP Deepwater Horizon and many more.

Aug 1, 2013

By C. L. Emery, A. V. Corlett

"The stress equilibrium is disturbed in a body of rock by a mine opening and is restored by a redistribution of the stresses around the opening. The pattern of the redistribution of unilateral stress around an opening has been established by mathematical analysis and photoelastic measurements. The pattern for multilateral stress is found by superimposition of unilateral fields. The mathematical analysts do not use the elastic moduli as parameters and they are not significant in photoelastic work. The medium is isotropic. The concept of unilateral stress from vertical loading and the classical pattern of its stress distribution around openings does not explain commonly observed failures around the perimeters of mine openings. They show evidence of compression where tension is postulated.When it is recognized that few minerals and perhaps no rocks are Hooke Solids, most rocks must be St. Venant Solids. The components have varying degrees of elasticity and viscosity. The assembly will be-have elastically to rupture under shock loading, but when loaded short of rupture will adjust viscously to equilibrium. Similarly, the highly elastic components may initiate rupture before equilibrium can be established when stress is instantaneously relieved. Polycrystalline adjustments may produce permanent deformation. The mechanics of consolidation, especially in sedimentary deposits, ac-quire a stress component normal to the direction of compaction which can exceed that of the loading. It is one source of prestress. There are others. The principles of prestress design are based on the normal beam reactions, modified by a built-in compression in the lower chord. When the beam is loaded to design limits, the lower chord retains some compression and the whole beam depth is effective in compression. Some of the . common evidences of failure in compression over a mine opening can be duplicated in a prestressed experimental model.When the triaxial stress pattern is recognized and suitable measuring techniques are devised, mine design can be done on a rational basis."

Jan 1, 1959

By D. A. Rhys

"The Red Bluff porphyry is a tabular 2 km long north-west trending Early Jurassic quartz diorite to monzodiorite body that intrudes a folded Triassic greywacke sequence in the lskut River area, northwestern British Columbia. The porphyry is 500 m to 800 m northeast of the Snip orebody, which is a southwest-dipping shear-vein, termed the Twin zone that contains approximately 35 tonnes of gold.The intrusion associated with the mineralization is characterized by 0.3 cm to 4 cm phenocrysts of K-feldspar in a mediumgrained plagioclase porphyritic matrix. It is overprinted by pervasive sericite + quartz ± K-feldspar ± biotite (potassic) alteration characterized by intense stockworking of quartz veins containing magnetite--hematite bands. This assemblage is cut successively by quartz veins with minor iron-oxides and pyrite, and by younger pyrite veins with phyllic envelopes. The system is gold-rich but copper-poor, with typical grades between 0.25 g/t and 0.6 g/t Au, and 0.1% and 0.2% Cu. All styles of alteration and veining have similar abundances of these metals. Where southwest- and north-east dipping shear zones are developed in the porphyry, veins of all types are sheeted and foliation parallel. These sheeted zones are interpreted to be syntectonic. Asymmetric phenocrysts, folded veins and oblique foliations developed in the 130 haulageway of the Snip mine imply oblique normally-directed shear on the southwest-dipping foliation.The adjacent Twin zone is a high-grade auriferous shear-vein system that is internally banded with: (1) carbonate-chlorite-biotite veins, with textures indicating formation at least partially by wallrock replacement, and (2) dilatant quartz-sulphide veins. Veins commonly have potassic alteration envelopes that contain biotite ± calcite ± K-feldspar. The zone is highly deformed and schistose, with numerous kinematic indicators including shear bands, asymmetric folds, rotated porphyroclasts and oblique foliations that indicate a normally-directed shear sense which is parallel to that indicated by fabrics within the porphyry.Precious and base metal veins within 2 km or 3 km of the Red Bluff porphyry are zoned. Veins and shear-veins proximal to the intrusion, such as the Twin zone, are typically enriched in gold, copper and molybdenum, and have potassic alteration envelopes dominated by biotite. Distal veins usually contain relatively abundant zinc and lead and have sericitic alteration envelopes. Structures of both types have an Early Jurassic galena Pb-Pb isotope signature.The similarities in structural fabrics and alteration histories in both the Twin zone and the porphyry, the zoning of the vein systems in the area, and the apparently concordant Early Jurassic zircon U-Pb age from the porphyry and galena Pb-Pb dates from the Twin zone and surrounding vein systems suggest that intrusion, semi-brittle deformation and a large mineralizing hydrothermal system were closely related temporally and genetically."

Jan 1, 1995

By Jerry C. Tien, Yingjiazi Cao

"Coal spontaneous combustion (SponCom) is a natural phenomenon in underground operations, which can either happen naturally or be triggered by human activities. For underground operations, espe-cially in coal, SponCom can happen frequently as a result of air leakage, although its incubation period may vary depends on types of coal and surrounding environment, resulting in uncertainty in control. In China, most of the underground coal operations now use longwall mining method because of its superior safety, high productivity and efficiency. With an increased popularity, there is also an increasing necessity to study spontaneous combustion, its occurrence and management. There have been many theoretical analysis and experimental studies over the past half century hoping to understand the occurrence of coal combustion and its control measures to better understand the occurrence and to design controlling measures to limit the dam-age it causes. In this paper, research on coal spontaneous combustion fundamentals from these three aspects will be reviewed, gaps highlighted and possible directions for future studies. INTRODUCTION The history of anthropic development is the history of human's energy utilization progress. From the first usage of fire, people have been continuingly seeking energy resources on earth. Coal, as an abundant, economic and convenient source of fuel quickly became indispensable and made significant contribution to economic growth worldwide. With technology and societal development, people are becoming more and more coal-dependent, but at the same time, problems of fossil fuel combustion came into sight. In global coal mining industry, spontaneous combustion has now presented one of the most challenging safety issues, it is also believed that it has contributed significantly toward the climate change. It is essential that more effort be invested to examine the cause of SponCom and its control measures. Coal SponCom is a complex process, with both physical and chemical inter-actions among various interrelated factors such as local airflow distribution, ventilation pressure, methane emissions (if any), and physical surroundings underground. With the advent of powerful computers, simulation techniques and af-fordable modelling packages in recent years, significant advances have been made in understanding sponta-neous combustion. But because of the complex nature of combustion and varying underground conditions, there are still areas that need further examining. This paper will focus on illustrating the current research of coal spontaneous combustion and addressing research gaps and future study areas."

Jan 1, 2019

By Jean-François Dorion

In an underground mine rock reinforcement elements and surface support units are often exposed to conditions that make them susceptible to corrosion. These unfavourable conditions include high relative humidity, the presence of dust and various other particles in the atmosphere, splashing of water and gases from blasting and diesel equipment. The corrosion of support systems is often associated with a loss in capacity that can be a major safety and economic concern in underground mines. A support system is composed of several components such as bolts, mesh, plate, retaining nut, cable ties. Every individual component can deteriorate due to atmospheric or aqueous corrosion and consequently can damage the integrity of the support system. This paper reports the results of a 5-yr study on the loss in capacity of individual support and reinforcement components at selected underground hard rock mines. As part of this investigation corrosion coupons were installed at selected locations at participating mines. A number of these coupons were recovered at regular time intervals and analysed for any signs of corrosion and subsequently tested to quantify any loss in capacity. The testing of the corrosion coupons was complemented by similar tests on recovered mesh and friction bolt specimens from the site. The collected data have provided useful insights on the factors that contribute to the corrosion of support systems. This knowledge can aid in the selection of appropriate support strategies and a reliable assessment of the predicted useful life of a support system and the need for rehabilitation.

Jun 1, 2012

By G. W. Sparkes

The use of CR-39 plastic polymer as a solid state nuclear track detector in the textural analysis of radioactive minerals in geological samples was first described by I.R Basham in 1981. CR-39 autoradiographs provide a detailed, high-resolution image of the in situ distribution of the radioactive minerals within geological samples on both the macroscopic and microscopic scales. This technique is an inexpensive and effective means of obtaining detailed textural information that provides insight into the style of mineralization, its relationship to primary and secondary structures in the host rock, and its association with particular geological features or mineral phases. Although this technique does not provide any information on the identity of the minerals responsible for the radioactivity, the resultant autoradiographs can be used to select regions for further detailed analysis such as petrography, microprobe analysis, or SEM imaging. This paper summarizes the procedure and outlines the appropriate time and materials required for both the exposure and etching of the CR-39 with respect to the intensity of the radioactivity emitted by the geological samples.

Jan 1, 2013

By K. Iturralde

The topic of this article is the automation and robotization in refurbishment processes of industrial buildings. The need to mold these production spaces is quite universal. Particularly in the regions with a high industrial development and with a lack of buildable land, there is a need to convert this kind of spaces into an improved production system. The latest developments can be a useful tool for achieving a more efficient way of reforming this type of construction. On the one hand we have the digital or computerized 3D Laser Scanning (Computer Aided Measurement) that allows an accurate 3D modeling of the entire building. On the other hand, the project management using BIM (Building Information Modeling) could provide an easy design of each of the elements of the refurbishment. Finally, through the production of construction elements using robotics as jig or for CNC (Computer Numerical Control) we achieve a neat production of each element. How can be all those technologies applied in the refurbishment or expansion of industrial buildings? The research takes a first approach and analyzes industrial buildings that can be called generic or not specialized. To narrow the field of refurbishment, three major factors are defined. The first is to minimize the bill of the energy consumption of the buildings. This could be done either insulating the envelope, reducing the waste-volume to be conditioned climatically or creating facilities for energy production. The second is that the refurbishment or expansion of industrial buildings should try not to interfere on the production process that takes place in the building. In other words, the assembly of the elements in the construction site should be quick and easy, causing the least of disturbance at the workplace. Finally, the research makes an approach towards a robot integrated industrial or productive building .

Aug 1, 2013

By Phillip J. Mackey, Gerardo R. F. Alvear F.

It is now 38 years since the publication of the first edition of "Extractive Metallurgy of Copper" by Professor W.G. Davenport and the late Professor A.K. Biswas. The text book would be issued in a total of five editions, soon became the standard for students and those in industry. Interestingly it was published at the onset of great change in the industry. This was a time when sulphur dioxide controls in the USA were introduced, and almost simultaneously, world oil shocks caused significant increases in the cost of fuel - all leading to efforts to adopt new technology and move away from the reverberatory furnace, which had no potential for sulfur capture and required large amounts of fuel. At the time of publication of the book, new processes such as the Noranda Process and the Mitsubishi Process were in their infancy, while flash smelting (which was first commercialized in 1949 at Harjavalta, Finland) had made significant in-roads in boosting copper output, with some 22 new flash smelters licensed by 1976. Computer technology and associated process control techniques were rudimentary compared to systems today, available physico-chemical data remained largely in tabulated format and needed to be manually entered into the main frame computers of the era, while modeling techniques common today had not yet been developed. The copper industry has therefore seen immense changes since the time of this textbook: world tonnage of smelted copper has risen from 7.34 million tonnes/year in 1976 to 16.7 million tonnes/year in 2012, over a two times increase. Technologies such as the El Teniente Process, or Top Submerged Lance technologies, typified by the ISASMELTTM, not commercialized at the time, now treat large tonnages of copper concentrate in a single furnace. Advanced heat and mass balance software and thermochemical modeling are now used extensively to examine chemical and physical characteristics for process design and to support process optimization. These changes in the industry have been chronicled in subsequent editions of the book. This paper looks at the issues and problems seen in 1976 and over the intervening years, and compares this with the challenges facing the industry with the available tools and technologies today. Some ideas looking into the future are also discussed in the paper.

Jan 1, 2014

By Chr. Krause

Within the scope the collaborative research centre 599 (Medical University of Hanover, University of Veterinary Medicine Hanover, University of Hanover) the behaviour of the degradation of magnesium materials as implants are investigated by using animal experiments (rabbits). Thus extruded cylindrical pins from the magnesium alloys MgCa0.8%, WE43 and LAE 442 were implanted intramedullary in the tibiadiaphyses. The implantation duration was 3 and 6 month. After the explantation 3 point bending tests were carried out to investigate the possible changes of the mechanical properties. Clearly changes in dependence of the implantation duration could be determined. The three magnesium alloys show a decrease of the mechanical resistance with an increasing implantation time. To evaluate the degradation process, wich is the reason for the changes, micrographs and element analyses (EDX) have been accomplished after the 3 point bending tests. The micrographs show for all used magnesium alloys corroded surfaces but no preferred corrosion on the grain boundarys. The element analyses show beside a layer which is rich in calcium and phosphorus an agglomeration of rare earth elements in this layer. With these results a using of magnesium alloys as a material for implants can be announced.

Jan 1, 2006

By A. Michalkow

DELN ITE Mines Limited is located in Deloro township, on the west end of the south break of the Porcupine Camp. Mining operations are currently being carried out on the downward extension of a system of quartz veins in an andesite zone. This zone has been followed from surface to the present bottom level of 5,250 feet. The changing mineralogy of the vein system has involved an increase in tourmaline content from the surface downwards, so that the veins at the lower levels are composed of dark brown quartz-tourmaline. The drilling problem presented by these extremely hard veins was partially alleviated by the development and adoption of a one-inch drill bit. All blast-hole drilling is now done with the one-inch bit, without any difference in hole spacing.

Jan 1, 1962

By Louis M. Perlman

CAN PRESENT TRENDS CONTINUE? Can population growth in the world keep going at the average rates of the last few decades, till, say, the year 2000? And beyond? At the same time, can we expect steady increases in mineral consumption per head, all over the world, as the living standards of many nations converge toward the living standards of North America? If they do converge? Does the total fund of world resources extend, with foreseeable techniques, to supplying the consequent demands for metals, non-metallic minerals and energy? Do we have the requisite economic and scientific techniques available to answer these questions? Certainly, we cannot forecast over decades with any certainty. There are many, of course, who seem to believe that by the simple fitting of trends, they can tell us something about the world and resource constraints in the year 2000, twenty-three years from now. It is significant that many studies of this sort have added sustenance to the 'doom-watching' fraternity of commentators. The reason is simple. The extrapolation of exponential trends into the distant future frequently leads to the most astounding and impossible scenarios. Another feature of exponential growth is the suddenness with which certain fixed limits are approached. It took world population two hundreds years to increase by 1/2 a billion, from 1650 to 1850. Yet some U.N. estimates suggest that the net addition to human population will be over 2 billion between now and the end of the century. Thus, the present world population would increase from a little under four thousand million today to rather over six thousand million in the year 2000.

Jan 1, 1977

By G. K. Quainoo

Investigation by researchers on the application of various thermo-mechanical process histories on 6000 series aluminum alloys have found improvements in mechanical properties of these alloys. However, natural aging, which is unavoidable in the automotive processing line, has been found to have deleterious effect on subsequent artificial aging properties in these alloys. In this study, the evolution of yield strength during natural aging modeled by Lloyd and Gupta has been adapted to investigate the effect of cold deformation on the natural aging kinetics in AA61 11 by means of tensile testing, differential scanning calorimeter (DSC) and scanning electron microscopy (SEM). Also, intermetallic particles in the alloy were extracted from the matrix and XRD performed on them to ascertain their composition and their role on the kinetics in the alloy. The results show that cold work effect on the natural aging kinetics of AA6111 is in very good agreement with the model proposed by Lloyd and Gupta. The kinetics of natural aging in AA6111 aluminum also decreases with increasing level of cold work. This is attributed to dislocations serving as sinks which consume quenched-in vacancies formed during the early stages of clustering. The phases of the intermetallic particles identified in AA6111 are those of a-A15Mn12Si7 and a-A15MnSi.

Jan 1, 2007

By G. S. Hume

Research thrives on ideas, and the theoretical considerations of today are either the discarded notions or the proven facts of tomorrow. The progress made in the past fifty years in the acquisition of knowledge of petroleum geology is no less astounding than is the tremendous increase in the production of oil on the North American continent from 61 million barrels in 1897 to 1,917 million barrels in 1947, an increase of 3,300 per cent, with production of natural gas expanding from less than 400,000 Mcf in 1897 to approximately 4,500,000,000 Mcf, or an increase of 11,000 fold in the same period. In the search for and discovery of the oil and gas fields that have yielded such prolific wealth, no idea has had a more profound effect than has the ?anticlinal? theory of oil accumulation, propounded in 1844 by Sir William Logan, the founder of the Geological Survey of Canada, after noting the position of oil seepages on the crests of anticlines in Gaspe peninsula. Sir William apparently was not much impressed with his own idea at this time, but after the Drake well discovery in 1859 and the publication by Henry D. Rogers, of Glasgow University, formerly of the Pennsylvania Geological Survey, of a paper in which he pointed out that the seepages in Pennsylvania were on anticlines, T. Sterry Hunt, an associate of Sir William Logan on the Geological Survey of Canada, published a reasonably comprehensive statement of the anticlina theory in the Montreal Gazette on March 1st, 1861. Hunt recognized the fact that the oil ?being lighter than the water which everywhere penetrates the rocks below the water level, naturally rises and accumulates along the crown of these anticlines". This was a recognition of the fact that gas, oil, and water in an anticlinal structure separate according to buoyancy or specific gravity. For some years the anticlinal theory does not seem to have attracted much attention, but when I. C. White in 1883 revived it and put it to practical use by prospecting for 'anticlinal' oil an gas structures in Pennsylvania, West Virginia, and Kentucky, its real value not as a theory but as a fact became widely recognized. Even today, the search for anticlines as oil and gas structures is being vigorously continued. In the past fifty years, however, it has become widely recognized that petroleum and natural gas collect in many different types of structures, and these have become known by the general name of 'traps'. About 1890, terrace structures were highly regarded because it was thought certain oil fields in Pennsylvania, New York, and Ohio were directly related to them. However, as Wilson (2, p. 437) has pointed out, it is recognized to day that ?'wherever the surface evidence is complete and dependable, other factors (than the terrace structure) are found to be in control'.

Jan 1, 1948

By József L. Margitfalvi

Different Au/MgO catalysts modified with Mn, and Fe were prepared by precipitation-deposition. The catalysts were characterized by XRD, FTIR, Temperature Programmed Reduction (TPR) and CO chemisorption and were tested in CO oxidation in the temperature range of 243-523 K. The catalytic tests using both Temperature Programmed Oxidation (TPO) technique and time on stream (TOS) experiments revealed the high activity of catalysts prepared. In TPO experiments the modification by Mn significantly increased the activity above 300 K, however in the subambient temperature range the activity decreased considerably. Catalysts modified by iron did not show any decrease in the activity below 300 K, while the activity at high temperature increased significantly. Catalysts modified by Mn, Fe showed higher activity, selectivity and stability in preferential CO oxidation, carried out in the presence of hydrogen than the unmodified Au/MgO catalysts. Results of in situ FTIR spectroscopy on both the base Au/MgO and the iron modified catalyst unambiguously revealed the formation of ionic gold in the presence of CO/O2 mixture. The formation of this species was strongly hindered in catalyst modified by manganese. Results obtained strongly support the need for the formation of "metal ion - metal nanocluster" ensemble sites. These sites are involved in the activation of the CO molecule prior to its reaction with atomic oxygen. It is suggested that at subambient temperature these ensemble sites contain mainly ionic forms of gold, while at higher temperature iron or manganese ions are involved in CO activation.

Oct 1, 2003