Maschineller Streckenvortrieb im Bergbau — Entwicklung und Probleme

ZusammenfassungMaschineller Streckenvortrieb im Bergbau — Entwicklung und Probleme Die für den Bergbau verwendeten Vortriebsmaschinen, ursprünglich in den flachen und ungestörten Lagerstätten Nordamerikas entwickelt, erweisen sich in jenen Formen für die komplizierten Verhältnisse des europäischen Bergbaues meist als ungeeignet. In Europa sind eigene Wege der Entwicklung beschritten worden, die den Verhältnissen der größeren Druckhaftigkeit, Veränderlichkeit der Lagerstätten und Streckenprofile sowie der selektiven Gewinnung besonders Rechnung tragen. Hiedurch haben sich eigene Maschinenformen bei den Vollschnittmaschinen und besonders bei den Teilschnittmaschinen herausgebildet. Die Maschinen sind leistungsfähig und flexibel, doch werden die Streckenprofile häufig nach Gegebenheiten der Lagerstätte und betrieblichen Notwendigkeiten bestimmt, so daß nicht immer eine optimale Anpassung an die Druckverhältnisse erreicht wird. Zunehmend jedoch wird das Gebirgsverhalten mitberücksichtigt und die Profile werden dementsprechend ausgeführt. Probleme bestehen weiterhin beim frühzeitigen Einbringen des Ausbaues, bei der Orientierung der Maschinen, beim Wegfüllen in geneigten Strecken und bei quellendem Gebirge. Die Entwicklung geht aber weiter, Verbesserungen sind zu erwarten.

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SummaryMechanical Tunnel Driving in Mines — Development and Problems Heading machines for mining purposes have originally been developed in the flat, regular deposits of North America but are in that form hardly applicable to the complicated conditions of European mines. In Europe separate developments have taken place which allow better for the conditions of greater ground pressure, for the variation of deposits and drift cross sections as well as for the selective breakage and removal of minerals. Thereby particular machine types have been developed among the full-cut machines and especially among the partial-cut machines. They exhibit good performance and flexibility; however, drift profiles are often determined according to the conditions of the deposit or according to operational requirements so that not always an optimum adjustment to the rock pressure is reached. To an ever increasing extent, however, the rock pressure is being considered and profiles are selected accordingly. Difficulties still arise with respect to the early placement of support, muck removal in inclined openings, and in swelling ground. As the development does not-appear to be completed, improvements in these areas are still to be expected.

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RésuméCreusement mécanique des galeries de mines — développement et problèmes Les machines de creusement employées dans les mines ont été mises au point à l'origine pour les couches horizontales et uniformes de l'Amérique du Nord, mais le plus souvent elles se trouvent impropres aux conditions complexes des mines Européennes. En Europe on a pris des chemins particuliers qui tiennent compte spécialement des conditions de pressions plus grandes, de la variabilité des gisements et des sections des galeries, et de l'exploitation sélective. Pour cela, on a mis au point des machines particulières, non seulement pour l'attaque globale mais aussi pour l'attaque ponctuelle. Les machines ont de bonnes performances et sont adaptables, mais les sections des galeries sont déterminées fréquemment par les conditions de gisement et par la nécessité d'exploiter de manière à atteindre l'adaptation optimale aux contraintes des roches. Pourtant le comportement des roches est de plus en plus considérée pour le choix des sections. Il existe encore des problèmes pour l'application précoce du soutènement, pour l'orientation des machines, pour le chargement dans des galeries inclinées, et pour les matériaux gonflants. Comme le développement ne paraît pas complet, on peut s'atteindre encore à de nouveaux progrès.

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Vortrag, gehalten beim XIX. Geomechanik-Kolloquium im Oktober 1969 in Salzburg.

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Mit 11 Abbildungen     

The past star-formation rate and the initial mass-function in the solar neighbourhood

The present-day mass function and the kinematical data of the nearby stars are discussed as constraints on the time-behaviour of the star-formation rate and of the initial mass function during the evolution of the galactic disk. A recently suggested dependence of the initial mass-function slope on the heavy element abundance can not be excluded from this study. The average past star-formation rate is in the order of the present-day rate.Paper presented at a Workshop on The Role of Dust in Dense Regions of Interstellar Matter, held at Georgenthal, G.D.R., in March 1986.     

Surface representations reproducing given digitized contour lines

In the practice of administrative or engineering geosciences, the problem of deriving a digital surface representation from a map displaying contour lines of the interesting quantity is quite often encountered. First, alpha-numerical data are retrieved from the map by digitizing these contour lines pointwise into polygons. However, common gridding algorithms are known to fail at adequately reproducing the input contour lines due to the inhomogeneous and anisotropic areal distribution of the sites of the data sampled from given contour lines. Therefore, we suggest a new algorithm; the basic elements of its first stage are a constrained Delaunay triangulation of the data sites honoring their natural neighborhood relationship—i.e., whether they belong to the same contour line or not, and linear interpolation according to this triangulation of the data domain. In a second stage, a Bezier-Bernstein or simplex B-spline representation is easily achieved if a C₁ or C₂ smooth representation is required. At this stage, also, discontinuities of the function or its first directional derivatives with known locations in the data domain may be represented, provided this additional information has been taken into account when the triangulation was performed. The algorithm is numerically stable and efficient, and allows external interaction by the user to introduce his/her additional knowledge of the phenomenon to be studied, which may not be explicitly inherent in the available data.     

Coral Recruitment and Regeneration on a Maldivian Reef Four Years after the Coral Bleaching Event of 1998. Part 2: 2001–2002

Abstract.  This paper is the follow-up study to a quantitative inventory of stony corals on a Maldivian reef after the bleaching event of 1998 [Loch, K., W. Loch, H. Schuhmacher & W. R. See, 2002; P.S.Z.N.: Marine Ecology, 23 (3): 219–236] covering the years 2001 and 2002, thereby extending the observation period from 1999 to 2002. Data collection was performed as previously in transects on the reef flat, Acropora tables at the reef rim, Porites lobata blocks and one Diploastrea heliopora colony. While between 2000 and 2001 the transects showed a noticeable increase of living scleractinian colonies of 6.1 per m² of reef surface per year, this had slowed to 0.7 per m² per year by 2002. Likewise, the colonisation of dead Acropora tables had changed from a yearly increase of 14.4 colonies per m² of table surface between 2000 and 2001 to a decrease of 9.4 between 2001 and 2002. The main constituent of the regeneration in transects as well as on Acropora tables was Pavona (Agariciidae), whereas Pocilloporidae and Acroporidae were almost completely missing. A new immigrant was Tubastraea micranthus . Continuous growth of regenerates on Porites presented a columnar form, and the growth rate of D. heliopora was reduced between 2001 and 2002. The influence on reef ecology in terms of coral substrate, species differentiation, growth rate changes, interaction with other organisms and the overall prospect of the reef development on a longer timescale is outlined.     

Investigation of the geochemical impact of CO2 on shallow groundwater: design and implementation of a CO2 injection test in Northeast Germany

A small scale and temporally limited CO₂ injection test was performed in a shallow aquifer to investigate the geochemical impact of CO₂ upon such aquifers and to apply and verify different monitoring methods. Detailed site investigation coupled with multiphase simulations were necessary to design the injection experiment and to set up the monitoring network, before CO₂ was injected over a ten-day period at three injection wells, at a depth of 18?m below surface level into a quaternary sand aquifer located close to the town of Wittstock in Northeast Germany. Monitoring methods comprised groundwater sampling and standard analyses, as well as trace element analyses and isotope analyses; geoelectrical borehole monitoring; passive samplers to analyse temporally integrated for cations and multi-parameter probes that can measure continuously for dissolved CO₂, pH and electrical conductivity. Due to CO₂ injection, total inorganic carbon concentrations increased and pH decreased down to a level of 5.1. Associated reactions comprised the release of major cations and trace elements. Geoelectrical monitoring, as well as isotope analyses and multi-parameter probes proved to be suitable methods for monitoring injected CO₂ and/or the alteration of groundwater.     

Shadows in S/NB-events of jovian decametric emission

Narrow-band (NB) events in dynamic spectra and their relation with short (S-) bursts are an unresolved enigma of the jovian decametric emission. This paper is focused on the S/NB-structure with timescales between 0.03 s and 0.3 s. It is shown that the characteristic dash-line appearance of such narrow-band radiation in the dynamic spectrum could be considered as a result of superposition of numerous shadows events. To reproduce such shadows, the concept of the modulator is proposed. The modulator is an activating or amplifying agent, which drifts in the dynamic spectrum toward lower frequencies to stimulate the generation process in the radio source. After the source interaction, the modulator is shielded; one cannot stimulate the emission afterwards. Hence, the S/NB-emission shadows a certain region of the spectrum. This ‘shadow effect’ regularizes the random S-bursts or NB-oscillations into realistic structures in the synthetic spectrum. The resemblance between the real and the synthetic spectra is shown with 2D-correlation analysis.     

Wandel auf dem Gebiet der Gesteinsmetamorphose

Zusammenfassung Der Konzeption der metamorphen Tiefenzonen vonBecke undGrubenmann wurde im Jahre 1915 die Konzeption der metamorphen Fazies vonEskola gegenübergestellt. Während die Fazieslehre neutral und hypothesenfrei ist, postuliert die Tiefenzonengliederung vonGrubenmann feste Korrelationen zwischen Temperatur, allseitigem Druck und Stress bei der Metamorphose. Es wird gezeigt, daß diese Abhängigkeit nicht besteht, daß die Intensität der Metamorphose nicht von der Tektonik abhängig ist, und daß es keine Stress- und Antistressminerale gibt.Ein überblick über den heutigen Stand der metamorphen Fazies wird gegeben, wobei insbesondere Angaben über die Temperaturgrenzen von Fazies aufgrund der neuesten Experimente gemacht werden. Es wird nachgewiesen, daß die maximalen Drucke sowohl bei niedrigtemperierter als auch bei hochtemperierter Metamorphose um 10 000 Atmosphären betragen haben. Regionale Metamorphosen können bei jeweils sehr verschiedenen Temperatur-Druckverteilungen erfolgt sein, wodurch verschiedene Typen, verschiedene metamorphe Faziesserien entstanden sind.

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The concept of depthzones byBecke andGrubenmann is contrasted withEskola's concept of metamorphic facies. While the concept of metamorphic facies is neutral and free from any hypotheses, the concept of depthzones postulates a firm correlation between temperature, pressure and directed pressure (stress) during metamorphism. It is shown that this correlation does not exist, that the grade of metamorphism is not dependent on tectonics, and that stress minerals and antistress minerals do not exist. A brief survey is given of the present state of metamorphic facies. Physical conditions, based on most recent experimental investigations, are stated and graphically represented in Fig. 3.The maximum pressures in metamorphism of crustal rocks have been about 10 000 atmospheres, both when very low temperatures and rather high temperatures were effective. Regional metamorphism has taken place under the condition of very different pressure-temperature relations (geothermal gradients) thus having produced different types of metamorphism, or different metamorphic facies series.--qr (Becke Grubenmann) (Eskola). . , , , - , , . .

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Résumé En 1915 la conception du faciès métamorphique d'Eskola fut opposée à celle des zones métamorphiques de profondeur deGrubenmann. Le système du faciès ne part pas de suppositions hypothétiques tandis que la division en zones de profondeur queGrubenmann établit postule pour le métamorphisme des correlations invariables entre température, pression isotrope et stress. On démontre qu'un tel rapport fixe n'existe pas, que l'intensité du métamorphisme ne dépend pas de la tectonique et que des minéraux de stress et d'antistress n'existent pas.Une vue d'ensemble sur la situation actuelle des recherches portant sur les faciès métamorphiques est présentée et par là des données sur les limites de température des faciès sur la base des expériences très récentes sont fournies. Il est démontré que les pressions maximales qui sont atteintes au cours du métamorphisme non seulement à basse température mais encore à haute température se montent à 10 000 atmosphères environ. La métamorphisme régional s'est produit sous des conditions très différentes de pression et de température. Ainsi naissent des types différents de faciès métamorphique.

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Plenarvortrag auf der Geowissenschaftlichen Tagung in Berlin am 8. Oktober 1967.