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This paper examines the limits and pressures imposed on South African deep-level mining technology by changing economic and socio-political constraints that have obliged mining engineers to adapt their practices of "getting gold out of the ground." Initially employing straight-forward arguments about the importance of means for achieving ends, the paper eventually raises questions that complicate our understanding of practices that underlie simple conceptions of mining technology. [ABSTRACT FROM AUTHOR]

The term NATM was introduced by Rabcewicz during a lecture at the Geomechanics Colloquium in 1962. In this lecture, he summarizes the development of tunnelling methods and insight into mechanical processes in the ground over the last decades, and points out the positive experience made with a combination of shotcrete and rock bolts instead of the traditional timber or steel supports. Building on experience and development around the world, it has been Austrian engineers who have systematically developed and applied the method. In the beginning technological questions played a major role, but it was also clear that traditional design methods were no longer applicable. Thus it was still unavoidable to rely heavily on experience and observation. The importance of measurements for observing the system behaviour has been acknowledged, and techniques have been developed considerably further since then. Parallel to gaining more experience with the method in all kinds of ground conditions, contractual practices have also been further developed with the aim of establishing rules, which allow fair compensation of the contractor in spite of all the inherent uncertainties. In Austria, tunnel design practice has been standardized by the introduction of a guideline. Some of the factors contributing to the success of the method are the awareness of the client of his responsibilities, appropriate site organization, qualified engineers and miners, practically oriented research and education, as well as extensive exchange of experience. Der Begriff NÖT wurde von Rabcewicz geschaffen, der ihn erstmalig beim Geomechanik Kolloquium 1962 verwendete. In seinem damaligen Beitrag fasst er die während der letzten Dekaden entwickelten Tunnelbaumethoden und die Vorstellungen über die Mechanik der Vorgänge im Gebirge zusammen. Aufbauend auf vorliegenden Erfahrungen und Erkenntnisse haben überwiegend österreichische Ingenieure diese Methode entwickelt und umgesetzt. Standen anfänglich Probleme einer praktischen Umsetzung im Vordergrund, so war doch klar, dass die traditionellen Planungsgrundsätze der Vergangenheit angehörten. Deswegen musste man sich noch überwiegend auf Erfahrungen und Beobachtungen stützen. Von Anfang an wurde die Bedeutung von Messungen zur ingenieurmäßigen Erfassung des Gebirgsverhaltens erkannt und deren Weiterentwicklung laufend vorangetrieben. Parallel zur erfolgreichen Anwendung der Methode in allen Gebirgsarten wurden auch Vertragsmodelle entwickelt, die eine faire Vergütung bei wechselhaftem und unvorhersehbarem Gebirgsverhalten ermöglichen. Zur Gewährleistung einer strukturieren geotechnischen Planung wurde eine eigene Richtlinie erarbeitet. Für den Erfolg der Methode sind entscheidungswillige und sachkundige Auftraggeber, eine entsprechende Baustellenorganisation, qualifizierte Ingenieure und Mineure, eine praxisorientiere Forschung und Ausbildung und schlussendlich ein intensiver Erfahrungsaustausch notwendig. [ABSTRACT FROM AUTHOR]

The calculable magnitudes of the anomalous magnetic field from simple 2D sources and their gradients and Laplacians appear as ratios that can be synthesized in functional forms, corresponding to the different source shapes. Field components and first-order derivatives are involved in the inversion procedures presented. The structural index and source depth are estimated independently of each other. The applied functions allow magnetic profiles and magnetic maps to be shape- and depth-converted with immediate imaging of the inversion results. The contours of these functions outline elongated loops around the 2.5D anomaly axis on magnetic maps. The width of the loops reflects the depth and structural index N of the source in the scale units of the inverted map. Model and field tests illustrate the effectiveness of this approach for fast automatic inversion of large sets of magnetic data for depth, shape, length and location of simple sources. [ABSTRACT FROM AUTHOR]

The article focuses on the emergence, professionalization and education of a British-based mining and metallurgical elite in the years between 1851 and 1914. The last few years have witnessed a growing appreciation among students of international business of the extensive British involvement in overseas mining in the late nineteenth and early twentieth centuries. In examining the leading role of the "City of London," in mining finance and speculation, J.J. Van Helten has shown that between 1880 and 1913, some 8,408 companies were registered in Great Britain for mining and mine exploration abroad. Many of these companies were of little consequence, and it is hard to estimate with any precision the amount of cash actually invested. Nonetheless, it is clear that the overseas mining investment boom was of great consequence and that Australia, Africa, Europe, Asia, North America and South America all proved attractive to British mining entrepreneurs and investors. British-owned companies, for example, accounted for 60 per cent of the world's output of gold in 1898, and by 1914, 20 of the world's largest copper mines, a quarter of the tin output of the Straits Settlement and Malay States and 60 per cent of the Chilean nitrate industry was owned and controlled by British-based firms.

The article reports that a mining engineer from Great Britain has been accused of economic crimes and was believed to have stole and smuggled titanium, uranium, and iron ore.