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By Li. S., C. Sili

Abstract. Study on nonlinear damage localization process of rocks under water chemical corrosion is a more interesting topic in rock mechanics research world widely. It is very important in estimating long term stability of rock engineering, design of nuclear waste repository and its performance estimation, geothermal and petroleum development. This paper reports that new development of study on the topic, including methodology, results of meso-mechanical test, real-time CT scan test and acoustic emission test, temporal fractal behaviors, neural dynamic modeling and chemical-induced damage law, etc. This paper also discusses the research directions of the topic in the near future. Zusammenfassung. Untersuchung zum durch die chemische Corrosion induzierten Schaedigungsprozess ist einer der Trends im Gebiet der Felsmechanik. Sie ist zugleich ein sehr wichtiges Forschungsprojekt u.a. fuer geotechnische Langzeitstabilitaetsanalyse, Langzeitsicherheit eines Endlagers, Erdwaerme- und Erdoelfoerderung. Dieser Aufsatz stellt die neusten Entwicklungen in den folgenden Teilgebieten zusammen: Untersuchungsmethoden, Laborversuchsergebnisse der Mikromechanik, der Computer-Tomographie und der akustischen Emission, zeitabhaengige Fraktaleigenschaften, Modelle fuer die Nervendynamik sowie Modelle fuer chemie-induzierte Schaedigungen. Zum Schluss werden kuenftige Forschungsschwerpunkte bzw. –richtungen diskutiert. Résumé L’étude du processus de la localisation de l’endommagement du à l’érosion chimique est un thème d’actualité pour la mécanique des roches. Elle est également un sujet de recherche d’importance dans l’évaluation de la stabilité à long terme des ouvrages rocheux, l’analyse du system de stockage des déchets nucléaires et l’évaluation de son comportement, l’exploitation de l’énergie thermique et pétrolifère, etc. Cet article présente le développement actuel dans ce domaine, incluant la méthodologie d’étude sur le processus de la localisation de l’endommagement dû à l’érosion chimique, l’analyse des essais mécaniques avec l’observation microscopique, du balayage en temps réel (CT), et de l’émission acoustique. On aborde ainsi modèle des caractéristiques fractural du temps, le modèle de la mécanique dynamique neural, ainsi que la loi de comportement d’endommagement dû à l’effet chimique. Enfin, les perspectives relatives à ces études sont présentées et discutées.

Jan 1, 2003

By C. W., Davie

"DEFINITIONDiatomaceous earth consists almost entirely of the silicious remains of minute flowerless aquatic plants known as diatoms. The name diatomaceous earth, therefore, is to be preferred to others such as trade names, inappropriate terms, or names correctly applied to some other product. The following names should, therefore, not be used for diatomaceous earth,-- kieselguhr, infusorial earth, diatomite, celite, moler, bergnehl, English rottenstone, tripoli, tripolite, fossil earth, desmid earth, white peat, tellurine, randanite, ceyssatite, or any trade name.FORMATIONDiatoms live in practically all kinds of water, fresh or salt, hot or cold, still or running and under different conditions of depth and pressure. These minute plants assimilate inorganic salts from their environment and produce skeletons of silica much as mollusks secrete lime and form their Shalls. When the diatoms die they settle to the bottom together with anything else which may be present, such as sand, clay or volcanic ash. The organic matter gradually disappears leaving the silicious skeletons of the diatoms which, with impurities, make up the deposits of diatomaceous earth. These deposits which are still being foamed at the present time and which were produced throughout very different epochs, were more prolifically formed in the Tertiary, so that the thickest beds so far discovered are of that Age."

Nov 1, 1925

By Clark P. Mangelsdorf

The report consists of two parts. In Part I is a state-of the-act study of roof truss technology as of January 1979. Included are a history of the truss concept, a review of analysis techniques, a record of hardware available and equipment used in its installation and numerous examples of user experience. Part II is concerned with a study of the role of friction in the behavior of a roof truss. The appendices include laboratory tests by the author.

Jan 1, 1979

By Suk han Jang

This paper describes the tower foundation design and construction experience for the 345kV Youngheung marine transmission line, which has been in commercial operation in Korea since July, 2004. This transmission line was designed and constructed to meet the rapidly increasing power demands of metropolitan areas and supply stable, bulk electric power from the Yonghung thermal power plant into metropolitan areas. This transmission line passes over the west sea, Lake Sihwa and over land. In order to successfully complete this project, and to safely support the tower during severe maritime conditions, several types of tower foundation such as Pad and Chimney foundation, Pier (Cylindrical) foundation, R.C.D foundation, Jacket pile foundation and Steel pipe pile + concrete mat foundation were developed and used. As the world?s first and longest marine transmission line, the 345kV Yonghung marine transmission line operates successfully, thanks to several high-tech civil engineering technologies and KEPCO?s accumulated experience.

Jan 1, 2007

By H. P. LeVan

The aced for reliable reserves of the essential element, manganese, has been a continuing concern of the Federal Government for more than three decades. Because of the increasing vulnerability of outside sources of supply efforts have been intensified to find a means for beneficiating United States domestic deposits. The deposits of most interest would of necessity be near, or have access to, suitable transportation to processing plants. The Georgia manganiferous iron deposits represent some 10 million tons4 of ore readily available to southern iron and steel industries, if a manganese recovery process capable of functioning in the presence of large quantities of iron can be developed. In addition, a successful method for beneficiating the Georgia ore could produce a significant quantity of high-grade iron concentrate. The Differential sulfatization process developed 47 the Bureau of Mines5 seemed to be well suited for this application, particularly because it results in low concentrations of iron in the leach liquors with relatively complete extractions of manganese. In this process, manganese in the presence of iron is preferentially reacted with sulfur dioxide at elevated temperatures and subsequently extracted with water.

Jan 1, 1962

By William G. Doepken

With most of the mining industry emerging from the deepest business recession in 50 years, primary attention must be given to surviving in a business climate where dominant foreign competition, depressed prices, and potential overcapacity hang heavy over much of the industry. While already shackled with regulatory constraints, restrictive work rules, and high labor costs, mine operators are faced with the difficult task of reducing costs and improving productivity while operating at less than full capacity. To counter these nearly over-whelming factors, the mining industry must continue at the national level to seek regulatory relief and a rational policy toward foreign competition from government-controlled mines. In addition, dialogue with labor organizations must continue to minimize the impact of labor costs, cost escalators, and antiquated work practices. Although national and international actions have a tremendous impact on the future of domestic mining operations, local actions by mine operators to dramatically improve mining productivity will strengthen the industry's competitive stance. Before any substantial progress can be made, however, mine operators must recognize and define areas that depress productivity and establish goals and measures for improvement. Once problem areas are defined, a combination of technological and motivational concepts can be applied to improve productivity. Timing of Improvements While there is an immediate need for productivity improvements, only certain concepts offer near-term improvement potential while others must, of necessity, fit into a mid-range or long-range time frame. Near-term solutions (immediate to one year) likely will involve motivational concepts - work incentives and training - coupled with available technological concepts that require little capitalized development or site testing. Mid-range solutions (one to three years), by contrast, will include technological improvements in mining equipment, techniques, and systems automation. These concepts require a longer period of capitalized development and site testing before use. Long-range solutions (three years or more), which include adoption of new mining methods and computerized control systems, will appear only after prolonged research and capitalized development programs. Motivational Improvements Developing motivational con-

Jan 11, 1983

By Horace T. Reno

This information circular surveys the iron are industry of the world. It presents a comprehensive statistical record through 1970 of the U.S. iron ore industry and world trade patterns. The supply position of the United States and the other principal industrial countries of the world are summarized; detailed information is given on iron are production, consumption, imports, exports, mine capacities, substitutes, properties, and uses. There is a generalized discussion of the technology of mining and smelting iron ore, with a selected bibliography on the current state of these arts. The circular contains a summary economic account of world iron are resources, and discussions of the structure of the domestic and principal foreign mining industries, iron are mine employment and labor productivity, research and development, legislation, government programs, and strategic factors.

Jan 1, 1973

By Harlan A. Walker

This paper on the mines of El Potosi Mining Co. is one of a series being prepared by the United States Bureau of Mines on mining practices, methods, and costs in the various mining districts of North America. Grateful acknowledgment is made of the helpful suggestions and criticisms offered by the management, together with the assistance of the mining staff in preparing maps and drawings and of C. L. Thornburg, mine geologist, in preparing the section on geology.

Jan 1, 1934

A brief review is given of the history of the Colliery to date together with the reasons for the development of an additional seam.Investigations into the quality of the coal ami its suitability for the production of metallurgical coke and determination of the economic mining limits and coal reserves are discussed. The commencement of mining operations and the inter-seamarrangements necessary for the disposal of coal won are described with the stages in the opening out of the seam itself and the reasons for the installation of a 48-in. trunk conveyor belt. Choke and manning of face equipment are considered and also the work of secondary development and pillar extraction.It is concluded that with modern face equipment and conveyor belt lines, concentrated mining followed by immediate extraction of pillars is practicable and is giving excellent results at Burwood Colliery.INTRODUCTIONBurwood Colliery, the total holding of which now comprises some 3,140 acres of land and 1,450 acres of sea leases, has mined the Borehole Seam since 1883. The early work took place from Nos. 1 and 2 shafts at Glenrock Lagoon and later on at Nos. 3 and 4 shafts at Whitebridge to which the centre of operations shifted in 1893, shaft sinking at this latter area having commenced in 1888.As all the early operations were confined to the Borehole Seam, reserves of coal on this horizon had been considerably reduced by the mid 1930's, so a cross measure drift was driven to the Victoria Tunnel Seam which is about 300 ft. above the Borehole Seam, and fully mechanized coal winning commenced from the second seam in 1938. Subsequently this cross measure drift was extended to the Borehole Seam and complete mechanization of the south-west sections of this seam achieved by 1945.Four track mounted mechanical units were put into operation in the latter area and these worked in a southerly and...

Jan 1, 1958

By C. Lemire, A. Biscaro

Ferro-alloys are sold according to the size grading specifications of users. Fines are produced during crushing and the amount produced depends on the crushing process and the physical characteristics of the ferro-alloy. The market value of fines has declined. Market demand is very weak and in some extreme cases is nonexistent. An induction furnace melt process has been developed to solve this problem. The process feasibility has been demonstrated on a small scale with charges of approximately 2.5 kg. The piloting was carried out using a 100 kW furnace with a metal liquid capacity of 140 kg. The operating parameters were determined during the pilot process. The procedures were defined and the equipment required for melting fines produced at the client's site was sized. With the production of ingots, the client can now recover the full value of ferro-alloy fines.

Jan 1, 2004

By Koichi Kobayashi

Performance-based approach to design of structures including foundations was adopted after enforcement of the revised Building Standard Law in Japan in 2000. The use of piled-raft foundation is favorable for medium-rise buildings in soft ground because of its good performance. In the design of the piled-raft foundation (Architectural Institute of JAPAN2002), vertical load is usually carried by the raft foundation, while the pile is primarily meant to control settlement of the structure. Shaft friction is expected to be larger in a nodular pile(Karkee, et.al., 1998) since it has larger surface area than a straight pile, and such piles are frequently used in piled-raft foundations. Since few structures with piled-raft foundation exist currently, the settlement characteristics of piled-raft foundation have not been fully clarified. To design piled-raft foundations with better confidence, the mechanism of vertical bearing capacity and the spatial distribution of settlement should be clarified, for which the actual behavior of the building-foundation system needs to be evaluated. This paper presents observations of settlement of a building with a piled-raft foundation at a soft ground site. The building is a steel structure covering an area an 766 m2, and consists of two-storey office block and one-storey warehouse block. The filled ground of about 5-m thickness at the ground surface is underlain by approximately 4-m thick alluvial sand layer below which lies about a 17-m thick alluvial clay layer with SPT N-value less than 2. The piles used in the piled-raft foundation are 12-m long nodular piles with nodal diameter of 500 mm (pile shaft diameter is 400 mm). The bored pre-cast piling method (Karkee, et.al., 1998) was used to install the piles. To evaluate the foundation settlement, the method of analysis of three-dimensional frame system, utilized widely in Japan, was adopted in combination with the foundation system. Basic assumptions were: (i) total ground settlement is evaluated as the sum of immediate settlement and consolidation settlement, (ii) immediate settlement is evaluated from the Mindlin?s solution in which strain dependency of shear modulus of soil is considered, (iii) settlement in clayey layers is evaluated by the one-dimensional consolidation theory, and (iv) shear spring between soil and pile shaft is represented by a hyperbolic function. The applicability of the method of analysis was verified by comparison with results of field monitoring of building settlement.

Jan 1, 2006

By Timothy J. Rohrbacher

This report presents a U.S. Bureau of Mines study that incorporates coal mining factors, coal recovery factors, and economic factors into the definition of an economically recoverable coal resource. The relationship between these factors to the Energy Information Administration's estimate of U.S. coal resources-the "Demonstrated Reserve Base"-is discussed. The Boltsfork 7 1/2-minute quadrangle in eastern Kentucky was selected as the study area. Results indicate that of the original 280.2 M tons of resource in the quadrangle, only 99.8 M tons (35.6%) is recoverable at a mining cost of $25 per ton or less.

Jan 1, 1994

The U.S. Bureau of Mines (USBM) was established in the public interest to conclude inquiries and scientific and technologic investigations on mining and the preparation, treatment, and utilization of mineral substances; to promote health and safety in the mineral industries; to conserve material resources and prevent their waste; to further economic development; to increaseee efficiency in the mining, metallurgical, quarrying, and other mineral industries; and to inquire into the economic conditions affecting those industries. The organic act of the Bureau, as amended by Congress and approved February 25, 1913, made it the province and duty of the U.S. Bureau of Mines to "disseminate information concerning these subjects in such manner as will best carry out the purposes of this Act." In accordance with this directive, USBM reports the findings of its research and investigations in its own series of publications and also in articles that appear in scientific, technical, and trade journals; in proceedings of conventions and seminars; in reference books; and in other non-USBM publications. The number of these reports, the wide range of subjects they cover, and the variety of mediums in which they appear make this kind of list both necessary and valuable. This edition describes reports and articles published during calendar years 1992 and 1993. It supplements the 50-year list of Bureau publications from July 1, 1910, to January 1, 19602; and these 5-year lists of publications and articles: from January 1, 1965, to December 31, 1969\ from January 1, 1970, to December 31,19745, from January 1, 1975, to December 31, 19796, from January 1, 1980, to December 31,19847, and from January 1, 1985, to December 31, 19898?.

Jan 1, 2007

By G. Song

"SynopsisAccording to the overlying rock strength and thickness of 10 shallow coal seams in China, the strata are classified into four types: weak and laminated strata (hereinafter referred to as WL), weak and massive strata (WM), strong and laminated strata (SL), and strong and massive strata (SM). The four types of strata, together with longwall panel height (M), panel length (L), and seam depth (H) are factors that influence the loads on hydraulic power supports. Principal component analysis was used to study the seven influencing factors. It turns out that seam depth (H) is multicollinear with WL, WM, SL, and SM. Thus the enumerated seven factors are divided into two models. In Model 1, six factors; panel height, panel length, and layer thickness of the four type strata are involved. In Model 2, three factors; panel height, panel length, and seam depth are included. Using multivariate regression analysis, two equations to calculate loads on supports are obtained for each model. The equations were applied to shallow coal seams. The equation of Model 1 is more accurate than that of Model 2, but Model 2 could be further used in deep coal seams. The equations were coded through VB programming to simplify the calculation.IntroductionTo ensure coal production in the long term, the focus of coal mining has been gradually shifted to the western areas of China in recent years due to rich coal resources in this region. Most of the coal seams in this area are shallow but the support loads are abnormally high. In these circumstances, the chock loads estimating methods used in the past do not work. If the rated working resistance of a support is larger than needed, the shield is unable to fully perform, while a lower working resistance would lead to accidents like shield crushing or even casualties. This problem is frequently found in shallow coal seams such as Shenfu-Dongsheng, Yulin, Tuha, Lingwu etc. (Zhang, 2011). Thus, to ensure safety and efficiency during mining, the estimation of support loads and selection of supports are of great significance."

Jan 1, 2015

æSustainabilityÆ is one of those words that has gained more usage in popular discourse than in the dictionary. In fact it is not in many dictionaries at all. Typically, given this, it also seems to mean different things depending on whose lips it emerges from. It is now like a code word in that if people say it, you donÆt have to think about its meaning; it is just æthereÆ and is taken for granted. This is a problem for the mining industry as we are now using the term too and to be effective in what we do, we need to have a reality check and see how those outside who have views on us (æstakeholdersÆ maybe) use it. The core issue seems to be æsustainability of whatÆ: the industry?, a company?, the global environment?, particular ecosystems?, the community? At these levels, the term seems almost meaningless. If we do not even agree on what it is, at least broadly, our communication and possible partnerships for going forward will be difficult to say the least. One reference to æsustainÆ in my thesaurus is: æTo keep from failing during stress or difficultyÆ. This may be a clue to something approaching a common notion. I suggest that to use æsustainabilityÆ we make the following assumptions:that we are talking about human activity aimed at making a living that has an impact on the natural and social environment; that humans must make a living (though what this needs to include is problematic); that the impact of particular activities has been problematic to date and needs to be monitored, altered, stopped, etc; that there is stress on both social and natural environments; and that change can be effected in order that particular activities such as mining minimise their negative effects and maximise their positive. This is why we are taking part in sessions such as this one today. Two more initial observations: First, it strikes me that even with the above assumptions laid out, æsustainabilityÆ and æsustainable developmentÆ are too abstract and general as concepts. We have to break these high and mighty ideals down into workable, bite-size chunks, into practical ways of dealing with the world outside our sites and companies. Second, sustainability, on both sides of the fence, too often focuses on nature and environment as though they are independent of people and community. I would argue, perhaps provocatively, that sustainability is primarily a people issue and has to be tackled as such. I want to look at the overall climate for business today and how it has responded before I return to what we can and need to do as the mining industry to make æsustainabilityÆwork.

Jan 1, 2002

By A. T. Haile

Detailed monitoring of the response of the rock mass between rockbolt reinforcement units subjected to a simulated seismic source has been successfully conducted. This work has shown the increase in amplification of the Peak Particle Velocity (PPV) with distance from a rock bolt unit, and, a minimum PPV for rockburst damage for the given site characteristics. This understanding, at this site, will allow the design of a suitable rock bolt spacing to prevent unravelling of the rock mass between the rock bolt units for a given level of seismicity. Or, alternatively, an estimation of the requirement for a suitable fabric support system, for the anticipated level of seismicity, can be made.

Jan 1, 2001

By J. J. Brummer

The possibility of diamonds occurring in Canada was first raised by W. H. Hobbs in 1899, who concluded: "that the apex of the fan of diamond distribution probably lies somewhere in the strip of the territory bordering James Bay on the east." This was based on the occurrence of diamonds in surficial sediments at various locations south of the Great Lakes. There are two recorded discoveries of drift diamonds in Ontario: (a) the Peterborough Diamond, 33 carats in size, poorly documented and found sometime before 1920;and (b) the Jarvi Diamond, 0.255 carat, found during 1971 in Sheraton Township near Timmins . Both discoveries were in surficial sediments and their source(s) have not been located. During 1960, Selco Exploration Company Ltd. started a heavy-mineral sample program of river gravels in the James Bay Lowlands of Ontario. This was continued by Canadian Rock Company Ltd. (1962-1963) and the Ontario Division of Mines (1973). The surveys discovered the presence of kimberlite minerals in gravel samples from streams draining the Moose River Basin. A total of 53 pyrope grains, four magnesian ilmenites and one grain of chrome diopside were identified from 32 sample locations. A study of the distribution of these minerals suggested the kimberlite source rocks to be located along the north margin or within the Kapuskasing gravity "high" in the area immediately south of James Bay. The Jarvi Diamond, found on an esker east of Timmins, could well have originated from this area. During 1965, an esker was sampled by the Geological Survey of Canada, and the results attracted attention to the area south of Lake Abitibi. At 9 out of 34 sites sampled along the Munro esker, Lee recorded the presence of pyrope garnets and very minor chrome diopside.

Jan 1, 1978

By P Rowe

New Zealand Steel's Taharoa titano-magnetite mine, south of Auckland, set two national load records when it transported around 2000 t of mining equipment three kilometres overland on time, under budget and without safety incident. It was the first time in New Zealand that four platform trailers were assembled end-to-end to transport a load. It was also the first time that a single load of 1000 t was transported on platform trailers. The need for the relocation of all equipment was realized five years ago. It took two years of planning and specialist advice to relocate the mine's 250 t dredge, 500 t surge bin, 1000 t concentrator plant and ancillary equipment from the Southern Mining Region across a specially designed haul road to the Central Mining Region. The project was carried out during a six-week shutdown in early 2001. Two dry docks were constructed, one at each end of the relocation route. The equipment was floated into a dismantling pond that was interconnected with the dry dock in the Southern Region. Through pumping, the water levels were controlled to allow transfer of the separated units from the dismantling pond into the dry dock. Once drained, sets of self-elevating platform trailers were used to transport the main units, one at a time, between the dry docks. Five prime movers were used to pull the loads. At the receiving end, the units were off-loaded in a dry dock interlinked with ,the first mining pond. The equipment was relocated because the reserves in the Southern Mining Region were mined out. A natural watercourse û the Wainui Stream û defines the northern boundary of the Southern Region and the objective became to relocate the mining plant to the other side of the stream and re-establish in the Central Region. The project team selected the trailers as the most effective means of transporting the equipment, particularly given the non-invasive means of crossing the Wainui Stream. Negotiations with prime contractor Tranzcarr Heavy Haulage Ltd commenced in mid-2000. The remainder of 2000 was spent in developing concepts with the contractor, detailed designing, preparing the dry docks, haul road and initial mine plan for the Central Region. These activities occurred with no conflict to the normal site production.

Jan 1, 2001

By Brad Thrall, Howard Bradley, Michael Samuels

"LOCATIONViceroy Minerals Corporation owns and operates the Brewery Creek heap leach gold mine located approximately 55 kilometers northeast of Dawson City, Yukon Canada. Dawson was home of the Klondike Gold Rush 100 years ago. Upon startup in November 1996, the Brewery Creek Mine was the northernmost operating heap leach gold mine in North America and one of the most northern in the world. Located at 64"" 02' latitude, the mine is less than 300 km south of the Arctic Circle. Access to the mine is available at Kilometer 14 of the Dempster Highway, linking Inuvik, NWT and the Klondike Highway, 40 kilometers east of Dawson City. The immediate vicinity is the only part of Canada not glaciated in the Wisconsin advance, which has resulted in an oxide ore deposit due to approximately 80,000 years of weathering - an area unique in Canada.DESCRIPTION OF OPERATIONSIn order to utilize heap-leaching technology successhlly in an extreme northern climate, a number of design features were incorporated into the process flow sheet to operate on a year round uninterrupted basis. Winter temperature may dip below minus 50 ""C, demanding an approach to mining and leaching that is different from heap-leach operations in more temperate climates. Because of the severe winter temperatures, the mine operates approximately 2 10 days per year, while the leaching process is continuous on a year round basis. Run of mine ore (ROM) is placed on the heap beginning in mid April until late October. Overall gold recovery is projected to be 78% over a 325 day leaching cycle with annual production levels of 2.3 million tonnes of ore placed on the pad, with an average of 75,000 ounces of gold recovered per year. The recovery process utilizes conventional sodium cyanide leaching, carbon adsorption, high pressure stripping, thermal reactivation and acid washing, and on-site smelting.HISTORYFollowing a comprehensive governmental and public review of the proposed project, a Class A Yukon Water license was issued in August, 1995. Construction started in 1995 and leaching commenced in October 1996.A Socio-Economic Accord with the Tron Dek Hwech'in First Nations provides for employment, contract, and scholarship opportunities for First Nations citizens."

Jan 1, 1999

By Raymond J. Pichette

"Aeromagnetic data can be useful in helping to delineate structures and rock types in gold exploration. Magnetic anomalies associated with Archean volcanic belts in northeastern Ontario can be quickly and effectively analyzed in profile form with the use of model curves. The model curves help to locate contacts between strata. They also help to estimate the magnetite content of the rocks and their depth beneath overburden.An aeromagnetic map of part of Catharine Township, Ontario has been analyzed with the aid of model curves. Several magnetic rock types, potential fault zones and areas of relatively thick overburden were delineated.IntroductionIn any exploration program, a good understanding of the stratigraphy, rock types and structure enhances the possibility of success. For example, environments which host gold deposits in the Abitibi Volcanic Belt may be characterized as follows (Jensen, 1980; Pyke, 1980):(I) They have major faults, especially as tectonic boundaries between volcanic piles which include mafic and ultramafic rocks and clastic sedimentary rocks or gneisses.(2) They have subvolcanic felsic intrusions.(3) They have extensive carbonitization, with or without carbonate and sulphide-facies iron formation.In all cases, delineation of structure and rock type should be a major objective in exploration. The analysis of magnetic data can be a useful tool in this task. This paper is presented with the purpose of describing the application of the magnetic method to gold exploration in Archean volcanic terrains.Magnetic AnalysisTotal-intensity magnetic contour maps can be used to discriminate rock units according to differences in magnetization. However, because of smoothing of texture resulting from the compilation procedure and the fact that survey lines are widely spaced, contours should not be directly used for quantitative analysis. A much more definitive means of magnetic analysis is provided by the use of the original profile or chart recordings. Model curves provide a basis for analyzing these profiles both accurately and rapidly."

Jan 1, 1982