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1	Sulfur Isotope Abundances and Base Metal Zoning in the Heath Steele B-1 Orebody, Newcastle, New Brunswick Lusk, John 01 1900 (has links) <p> S^32/S^34 ratios have been determined between some coexisting sulfides from the Heath Steele B-1 orebody and five other stratiform deposits in the Bathurst-Newcastle area, New Brunswick, and in crushed ore samples and pyrites from three across deposit profiles in the B-1 orebody. Zn, Cu, Pb and Ag abundances have been established across the orebody. Fractionations of S^32/S^34 ratios between coexisting sulfides have been determined in heating experiments at temperatures of 350 to 500°C and isotope effects measured in aqueous precipitation and exchange experiments at 25°C. S^32/S^34 fractionations between given coexisting sulfides from all the sulfide deposits are found to show only small variations. Isotope exchange is generally rapid in dry sulfide systems. Metal sulfides in aqueous solutions are slightly enriched in S^32 relative to the H2S with which they precipitate or communicate. It is concluded that the sulfide deposits have been regionally metamorphosed. The origins that have been proposed for the deposits so far are discussed and a model is suggested to explain the sulfur isotope and base metal abundances in the B-1 orebody.</p> / Thesis / Doctor of Philosophy (PhD)
2	Numerical Investigation of Rock Support Arches Rentzelos, Theofanis January 2019 (has links) The Garpenberg mine, owned by the Boliden Mining group, has established a trial area at Dammsjön orebody in order to examine the possibility of increasing the productivity of the mine. The mine uses the rill mining method with a current rill height of 15 m. In order to increase the productivity, the mine is examining the possibility of increasing the height of the rill. The trial area is located at 882 m depth surrounded by dolomite on the hangingwall and quartzitic rock on the footwall side. Rock support arches have been installed, in addition to the regular support pattern, to test their effectiveness on stabilizing the ground around the drifts. The arches have been installed in every 6 m and every 3 m in different parts of the test area. Rock samples from the trial area were brought to the university laboratory for testing. The data gathered from the laboratory tests along with the data from the monitoring of the trial area were used to develop a calibrated numerical model. A three-dimensional (3-D) model was therefore created, by using the FLAC3D numerical code. After the calibration of the model a parametric study was conducted for different rill heights and different arch spacing to investigate the performance of the arches. Specifically, the case of no arch installation along with the cases of an installed arch every 6 m and 3 m were tested, for the rill heights of 15 m, 20 m, 25 m and 30 m. The study concluded that the arches assisted in reducing the ground convergence in the production drift. The results also showed that the total height of the rill bench yields regardless of its height. After the yielding, the rockmass can no longer support itself and caves under its own weight. The larger the rill height, the larger the volume of loose rock that has to be supported and thus, higher the convergence. Furthermore, it was also observed that, significant amount of convergence in the production drift occurred during the drifting of the top drive and less during the stoping of the rill bench. This indicates that, the timely installation of the arches is an important criterion for their performance. rock mechanics rock engineering rock support arches artificial pressure arches mining FLAC3D numerical investigation numerical modeling Dammsjön orebody model calibration rockbolt perfomance ground support field measurements displacements rock support yielding rock mass yielding point load test rill mining method Avoca mining method Boliden rill bench parametric study μηχανική πετρωμάτων μεταλλευτική υπόγεια έργα υποστήριξη σηράγγων μετατοπίσεις διαρροή βραχομάζας παραμετρική ανάλυση Ακαδημία Αθηνών bergteknik Geotechnical Engineering Geoteknik

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Sulfur Isotope Abundances and Base Metal Zoning in the Heath Steele B-1 Orebody, Newcastle, New Brunswick

Numerical Investigation of Rock Support Arches